• Title/Summary/Keyword: Marine Concrete

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The Relation between Narcissism and Alienations (자기애적 성격성향과 소외감과의 관계)

  • CHA, Ta-Soon
    • Journal of Fisheries and Marine Sciences Education
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    • v.14 no.1
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    • pp.27-42
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    • 2002
  • The psychiatry features of narcissism are molded by the outcome of a mismatch or lack of tension between the realistic self and the ideal self, and it is related to the problems of alienation. That is, the problems of alienation lead to the outcome of a mismatch between the realistic self and the ideal self by the unindividuality which lose a senses of the reality in all every things, and it make man to even more to give up the realistic self and to be alive powerlessness living. In this views, this study examined the relationship between narcissism and alienations or subfactors, and the concrete subscale of the Narcissistic Personality Scale which had a influence on the alienations to experientially investigate the relation between narcissism and alienations. Juveniles were administered both the Narcissistic Personality Scale and the Alienations Scale. The results showed a positive relationship between narcissism and alienations, and the alienations was influenced of the self-centeredness and the exploitation/Privilege subscale of the Narcissistic Personality Scale. Therefore, narcissists feel alienations too much, and the more a person has self-centeredness and exploitation/Privilege of narcissistic traits, the higher alienations is.

A Study on International Competitiveness Power of Higher Education (현대 고등교육의 국제경쟁력 강화 방안에 관한 탐색)

  • PARK, So-Young
    • Journal of Fisheries and Marine Sciences Education
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    • v.29 no.1
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    • pp.188-200
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    • 2017
  • The purposes of this study are to understand the international competitiveness of modern higher education and to search the tasks for strengthening international competitiveness of Korean higher education. I reviewed domestic and foreign trends for higher education and then analyzed the statistical status of Korea's higher education. And I proposed tasks for strengthening international competitiveness of Korean higher education. These included university specialization from an international perspective, securing excellent research resources, revitalizing international education cooperation, fair quality management of higher education institutions, learner-centered higher education reform. Subsequently it is necessary to systematically select the factors of international competitiveness of higher education and to propose concrete plans for improving international competitiveness of higher education.

A Study on the Grade Efficiency of Sturtevant Type Air Classifier (스터테반트 공기분급기의 분리효율에 대한 연구)

  • 정인기;박시우
    • Journal of Advanced Marine Engineering and Technology
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    • v.28 no.5
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    • pp.773-781
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    • 2004
  • This research was Performed to raise grade efficiency of Sturtevant type air classifier. to treat powder less than $74\mu\textrm{m}$ particle produced at the crushing process of the dry aggregates manufacturing system or concrete wastes recycling system. The experimental conditions were in the ranges. 0.85 to 5.15 $m^3$/s of primary air flow rate. 0.005 to 0.015 $m^3$/s of secondary air flow rate $30^{\circ}$ to $70^{\circ}$ of auxiliary blades angle. respectively. for 1.7~3.3 kg/min of the powder feed rate. It was found that the grade efficiency of the air classifier was increased as the baffle plate was attached at the expansion region. and the optimal operating conditions of the air flow rates and the blade angle were obtained. The fractional recovery curves from the experiments were well agreement with the theoretical one of Molerus model.

Rapid Chloride Penetration Test for Concrete Based on the Electrochemical Method (전기 영동법에 기초한 콘크리트의 급속 염소이온 확산 특성 평가)

  • Oh, Sang-Gyun;Park, Dong-Cheon
    • Journal of Navigation and Port Research
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    • v.34 no.10
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    • pp.787-792
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    • 2010
  • It is necessary to predict the penetration of chloride ions for designing RC construction in marine environments. However, it takes a long time to obtain chloride migration coefficients. Therefore, the rapid chloride penetration test (RCPT) is generally used to shorten the test time. But there is a difference between chloride migration coefficients determined by rapid chloride penetration tests and those based on exposure in marine environments. In this study, we evaluated the effect on the chloride ion migration coefficient caused by a change in voltage and NaCl concentration. We also compared the relationship between the chloride ion migration coefficient by RCPT and that by exposure in marine environments. As a result of the experiments, we found that there is only a small change in the experimental factors based on changes in voltage and NaCl concentration and since they are so small, we can conclude that they are in the range of experimental error and test results from chloride ion migration coefficients by RCPT and exposure were very different from each other. In the exposure experiments, when the water-cement ratio was increased, the smaller fine air gaps in concrete affected the chloride ion migration coefficient.

Characteristics of Eco-friendly Porous Concrete for Seawater Purification Using By-Products of Steel Industry (철강산업 부산물을 활용한 해수정화용 친환경 다공질콘크리트의 특성)

  • Han, Woonwoo;Lee, Byungjae
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.24 no.1
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    • pp.1-7
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    • 2020
  • As of 2018, Steel slag was generated approximately 24.23 million tons. Howeve, except blast furnace slag, steel slag is a typical by-product which does not have a clearly defined purpose in recycling. Thus, countries around the world are putting great efforts into developing a purpose for the recycling of steel slag. The vast habitat foundation of marine life has been destroyed due to recent reckless marine development and environment pollution, resulting in intensification of the decline of marine resources, and a solution to this issue is imperative. In order to propose a method to recycle large amounts of by-product slag into a material that can serve as an alternative to natural aggregate, the engineering properties and applicability for each mixing factor of environment friendly porous concrete as a material for the composition of seawater purification were in this study. Regarding the nutrient elution properties, it was clear that the nutrients continuously flowed out up to an immersion time by 8 months in natural seawater; the nitrogenous fertilizer displayed excellent elution properties in this regard.

An Analysis of Hydrophobic Characteristics of Concrete Surfaces by Antifouling Coating Agent using Cellulose Nonofiber and Alkyl Ketene Dimer (셀룰로오스 나노 섬유와 AKD를 활용한 방오 코팅제에 의한 콘크리트 표면의 소수 특성 분석)

  • Nag-Seop Jang;Chi-Hoon Noh;Hongseob Oh
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.11 no.2
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    • pp.120-129
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    • 2023
  • Marine structures are subject to damage not only from sea salt but also from the adhesion of marine microorganisms and suspended particles, which cause additional damages. In order to prevent this, periodic coating is employed in the case of vessels to maintain the necessary performance. However, it is true that periodic coating is difficult for concrete or steel support structures, and there is a risk of marine environmental pollution. In this study, authors developed an anti-fouling coating agent using eco-friendly materials that possess hydrophilic cellulose nanofibers and AKD(alkyl ketene dimer). To achieve a homogeneous mixture, the content of cellulose nanofibers was fixed at 1 %, and AKD, distilled water, and waste glass were mixed using a digital mixer and homogenizer. The contact angle of the prepared coated surface was observed to be over 130°, indicating sufficient performance even in a water droplet flow test with a 15° slope, suggesting self-cleaning capability. Furthermore, through the analysis of viscosity characteristics at different temperatures, it was confirmed that the application is feasible at room temperature. Microstructure analysis also verified that the coating agent is uniformly applied to the concrete surface.

Particle filter for model updating and reliability estimation of existing structures

  • Yoshida, Ikumasa;Akiyama, Mitsuyoshi
    • Smart Structures and Systems
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    • v.11 no.1
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    • pp.103-122
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    • 2013
  • It is essential to update the model with reflecting observation or inspection data for reliability estimation of existing structures. Authors proposed updated reliability analysis by using Particle Filter. We discuss how to apply the proposed method through numerical examples on reinforced concrete structures after verification of the method with hypothetical linear Gaussian problem. Reinforced concrete structures in a marine environment deteriorate with time due to chloride-induced corrosion of reinforcing bars. In the case of existing structures, it is essential to monitor the current condition such as chloride-induced corrosion and to reflect it to rational maintenance with consideration of the uncertainty. In this context, updated reliability estimation of a structure provides useful information for the rational decision. Accuracy estimation is also one of the important issues when Monte Carlo approach such as Particle Filter is adopted. Especially Particle Filter approach has a problem known as degeneracy. Effective sample size is introduced to predict the covariance of variance of limit state exceeding probabilities calculated by Particle Filter. Its validity is shown by the numerical experiments.

An Experimental Study for a Fatigue-Bond Behavior of RC Structures Considering a Reinforcement Corrosion and a Fatigue Loading (철근 부식 및 피로하중을 고려한 철근 콘크리트 구조물의 피로-부착거동에 관한 실험적 연구)

  • Jung, Ha-Tae;Choi, Seung-Won;Kim, Sae-Hoon;Kim, Ji-Sang
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.05a
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    • pp.274-277
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    • 2006
  • There are many structures attacked by chloride ions near a marine environment. And they are attacked by a salt of de-icing chemicals. So, the embedded reinforcement is corroded. In the same time, these are under a fatigue loading by a traffic loading in bridges. In previous studies, there are many researches that deal with a bond behavior under a monotonic loading according to the rate of a steel corrosion. But there are most cases that the steel corrosion and the repeated loading are acted on structures simultaneously. So, in this study, it is investigated a fatigue-bond behavior of RC structures under a steel corrosion and a fatigue loading. Main variables of the test are a corrosion of steel reinforcement and a level of stress.

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Classifying Seafloor Sediments Using a Probabilistic Neural Network (확률 신경망에 의한 해저 저질의 식별)

  • Lee, Dae-Jae
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.51 no.3
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    • pp.321-327
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    • 2018
  • To classify seafloor sediments using a probabilistic neural network (PNN), the frequency-dependent characteristics of broadband acoustic scattering, which make it possible to qualitatively categorize seabed type, were collected from three different geographical areas in Korea. The echo data samples from three types of seafloor sediment were measured using a chirp sonar system operating over a frequency range of 20-220 kHz. The spectrum amplitudes for frequency responses of 35-75 kHz were fed into the PNN as input feature parameters. The PNN algorithm could successfully identify three seabed types: mud, mud/shell and concrete sediments. The percentage probabilities of the three seabed types being correctly classified were 86% for mud, 66% for mud/shell and 72% for concrete sediment.

Corrosion Resistance of SD460 Reinforcing Rod by Ceramic Coating (SD460 철근의 세라믹 코팅에 의한 내식성 향상연구)

  • Park, Ki Y.;Lee, Jong K.;Hong, Seok W.
    • Corrosion Science and Technology
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    • v.8 no.4
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    • pp.157-161
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    • 2009
  • The corrosion resistance of reinforcing bar was studied to endure the marine environment during shipment. The red rust on the surface did not damage the adherence in the concrete structures, especially in highly alkaline environment, but made the consumer doubt of the quality. The passivation process by alkalization of the quenching water in the tempcore process failed to endure the long shipping period. The ceramic coating by sol-gel process improved the corrosion resistance without damaging the mechanical properties and adherence between concrete and reinfiorcing bar. Optimal concentration of the coating solution and coating temperature were tested. No additional energy was necessary for the coating process by spraying during cooling process, resulting simplified process and low cost. Salt spray test, cyclic corrosion test and atmospheric test were employed to confirm the resistance. The corrosion rates were presented by rating number and polarization resistance. The coating layer was examined by FIB, XRD and SEM etc.