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Liquidity and Mechanical Properties of Concrete by Fluidity Retention Agent Mix Rate Change (유지제 혼입율 변화에 따른 콘크리트의 유동성 및 역학적 특성)

  • Park, Byung-Kwan;Choi, Sung-Yong;Pei, Chang-Chun;No, Dong-Hyun;Han, Min-Cheol;Han, Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.89-92
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    • 2008
  • This research analyzed the basic characteristics of unhardened concrete and the compression strength characteristics of hardened concrete according to liquidity retention agent mix rate change to improve the liquidity fluidity retention performance of high performance concrete, and produced the following results. The moment fluidity retention agent is added according to fluidity retention agent mix rate change, which increased fluidity retention agent mix rate, slump flow decreased, and in the case of slump flow according to the progress time change by the fluidity retention agent mix rates, the more fluidity retention agent mix rate increased, the lower slump flow change rate became. The moment fluidity retention agent is added according to fluidity retention agent mix rate change, fluidity retention agent mix rate increased compared to non-mixture of fluidity retention agent, and the air amount by progress time change by the fluidity retention agent mix rates slightly increased, however target range is still met and unit volume mass is inversely proportional to air amount. Compression strength according to age progress by the fluidity retention agent mix rates was shown to increase slightly with increase in fluidity retention agent mix rate, and yet the difference was not significant.

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Design Healthcare Mobility Agent Module in Sensor Network (센서 네트워크에서 헬스케어 이동성 에이전트 모듈 설계)

  • Nam, Jin-Woo;Chung, Yeong-Jee
    • Journal of Korea Multimedia Society
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    • v.11 no.4
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    • pp.544-553
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    • 2008
  • The general sensor network uses bundle method to collect fixed information from sensor node. However, this method is difficult to actively cope with major sensing objects in healthcare environment including status and position change of person and change of surrounding environment. In order to support the healthcare environment, certain information should be provided in accordance with the change of status of person and surrounding circumstance and also must cope with the change of network type by movement of person. This paper analyzes LEACH protocol which guarantees effectiveness of network as it constitutes clusters between Agilla model that is a representative multi agent middle ware and surrounding nodes. Based on the result of this analysis, it suggests LEACH_Mobile protocol which guarantees node mobility that is the weakest point of LEACH protocol. Moreover, it designs mobility agent middleware which supports dynamic function change of node and mobility agent module which supports dynamic function change of mobile node as components of LEACH_Mobile routing module. In addition, it is definitely increase performance which in mobile node of transfer data rate through LEACH_Mobile protocol of simulation result.

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An Analysis of Concrete Characteristics by Admixing Agent and Additive Contents According to the Change of Unit-Water (단위수량 변화에 따른 혼화제 종류 및 첨가량별 콘크리트의 특성 분석)

  • Ryu, Hyun-Gi;Woo, Jong-Kwon;Cho, Myeong-Ken
    • Journal of the Korea Institute of Building Construction
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    • v.7 no.4
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    • pp.139-144
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    • 2007
  • The purpose of this study is to analyze concrete characteristics by admixing agent and additive contents according to the change of unit-water to identify its effect on compressive strength. First of all, as for flesh concrete, overall unit-water showed a tendency to decrease as component inclusion rate of admixing agent was increased. In addition, air content showed a tendency to increase by increasing WR, WB, NP series admixing agent contents, on the other hand, the change of air content was gentle by around $1.5{\pm}0.5%$ for S, T, M series agents. Bulk density showed an inverse proportion to the change of air content. As for hardened concrete, expression rate of 3-day age compressive strength was generally decreased for S, T, WR, WB, NP, M series admixing agent component. Also, expression rate of 7-day age compressive strength showed an excellent record for S, M series agents, and expression rate of 28-day age compressive strength showed a tendency to increase more than plain on the whole.

Physicochemical Analysis according to Temperature Changes of Iopamidol and Ioversol Formulation Contrast Agents (Iopamidol과 Ioversol 제제 조영제의 온도변화에 따른 물리화학적 분석)

  • Han, Beom-Hee
    • Journal of radiological science and technology
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    • v.43 no.4
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    • pp.273-280
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    • 2020
  • In this study, the P contrast agent of Iopamidol, which is a nonionic iodide contrast agent most commonly used as a vascular contrast agent in medical institutions, and the O contrast agent of Ioversol, were studied. The physicochemical changes according to the temperature change were compared and analyzed using the Bruker Avance 500MHz Nuclear Magnetic Resonance Spectrometer owned by the Korea Basic Science Institute (KBSI). There was no physical or chemical change in the O contrast medium of Ioversol formulation in temperature change. However, in the P contrast agent of Iopamidol, a doublet peak began to appear in the 1.1 ppm region of the sample at 60℃, and the doublet peak was clearly observed in the sample at 80℃. As a result of this study, 1H-NMR analysis revealed that the P contrast agent of the Iopamidol formulation was dissociated from chemical bonds as it rose to a high temperature of 60℃ or higher, resulting in the formation of foreign substances. It was evaluated that the O contrast agent of Ioversol formulation had physico-chemical stability than the P contrast agent of Iopamidol formulation. As shown in this study, it is necessary to analyze the physical and chemical changes of contrast agents according to various environmental factors.

A Proposal to Change Welfare Policy Principles for Agent Orange Exposed Korean Veterans (고엽제 피해자에 대한 국가 보상 현황 및 보훈 정책 원리 수정 제안)

  • Chung, Injae
    • Journal of Environmental Health Sciences
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    • v.40 no.2
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    • pp.157-170
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    • 2014
  • Objectives: Agent Orange TCDD has been related to serious diseases among Korean veterans who were exposed to it. Decades after the end of the war, however, its effects are still being debated. The object of this study was to examine various unmet needs raised among Agent Orange exposed veterans and their families and to find grounds of a new welfare policy for providing alternative legislation. Methods: Literatures concerning Agent Orange, TCDD, the associated diseases, compensation for veterans and Supreme Court sentencing were searched using PubMed, ProQuest, press news and relevant homepages. Results: Agent Orange exposed veterans are eligible for various benefits from the government, including disability compensation for diseases associated with exposure. The Ministry of Patriots and Veterans Affairs has classified certain diseases into two categories, Agent Orange sequela diseases and sequela suspect diseases and has provided differential benefits based on separated laws. Big differences exist in benefits to veterans and their families between the two laws. The absence of definite standards to classify the Agent Orange associated diseases was confirmed by recent Supreme Court sentencing which ruled in favor of US manufacturers. Conclusion: It appears that the evidence for cause and effect of Agent Orange related diseases would never be perfect. The results suggest a need to change welfare principles from presumptive or indefinite disease basis to exposure experiences combined with integrated disability evaluation. We propose to extend eligibility by enacting a new law for Agent Orange exposed Korean veterans.

Effect of Water Content Change of Soft Clay on Strength of Solidification Agent Treated Soil (연약점토의 함수비 변화가 고화처리토의 강도에 미치는 영향)

  • 김광빈;이용안;이광준;김유성
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.553-560
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    • 2002
  • The improvement effect of soft ground is estimated by unconfined strength mainly. The unconfined strength of solidification agent treated soil is likely to vary with ununiformed mixing ratio and water content change of in-situ ground place by place. So, it is unreasonable to apply a solidification agent mixing ratio obtained from laboratory test results on all over the soft ground. In this study, it was analysed how the unconfined strength would be effected by the water content of soft ground. For this study, a series of unconfined compressive tests are peformed on various water content soil samples. The test results showed that the strength was fallen to 30∼80% by two times increase of water content approximately, This means that strength of solidification agent treated soil is influenced greatly by water content of raw soft ground and mixing ratio of solidification agent. It was suggested that the method how to decide the mixing ratio with soft ground water content.

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Drying shrinkage and Pore Structure of Blast Furnace Slag Concrete Mixed Alkaline Stimulation (알칼리 자극제 혼입 고로슬래그 콘크리트의 건조수축과 공극구조)

  • Park, Ji-Woong;Lee, Gun-Cheol;Gao, Shan
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.32-33
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    • 2016
  • This purpose of this study is to find the properties of pore structure and length change of blast furnace slag cement added alkali powder stimulant on shrinkage reducing agent presence. In length change, the specimen added alkaline stimulant was smaller than normal blast furnace slag concrete. And the specimen added shrinkage reduction agent was confirmed to show smaller rate of length change than the length. In MIP analysis of 1day-age, 0.1㎛ subsequent pore amount of the specimen added alkaline stimulant was significantly smaller value the normal blast furnace slag concrete specimen.

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An Experimental Study on the Water Repellent Property of Mortar Applied Water Repellent Agent of Inorganic Polymer Type (무기질 폴리머계 흡수방지재를 도포한 모르터의 발수성능 평가에 관한 실험적 연구)

  • 김영삼;양승도;유재강;오상근
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.31-36
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    • 2002
  • Recently, more interests in surface treatment of structure with water repellent agent are steadily increased, But, investigation of its properties such as protection, durability, morphology of micro structure is not sufficient. Therefore, This paper is aimed for the investigation of water repellent property and change of morphology of micro pores in mortar that is treated by water repellent agent(Inorganic polymer based material). Water repellent property, water absorption coefficient, air permeability, porosity and the observation of micro structure was investigated in different water repellent agent type. The test results indicated that water repellent treated mortar showed low absorption coefficient and air permeability(breathing effect). This is why inorganic polymer is coated at the wall of capillary and micro pores, also, the volume of micro pore is reduced without the change of morphology in micro structure.

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Policy Diffusion in The Beer Game

  • Duggan, Jim
    • Korean System Dynamics Review
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    • v.5 no.2
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    • pp.175-197
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    • 2004
  • The research studies the classic beer game simulation model from a new perspective. It does so by providing each agent with two ordering policies, and creating a set of rules that allow an agent to change its policy. Such a change is triggered based on an agent's confidence in their own performance, and on the relative confidence of their nearest neighbour. The overall effect is that policy diffusion can occur, where, under certain circumstances, an agent will mimic the behaviour of its neighbour, if it believes that its neighbour is performing better. The motivation behind this research is to provide an experimental base upon which the decision making strategies of business agent can be studied.

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Influence of Cure Accelerator Content on Change of Crosslink Density by Thermal Aging in Natural Rubber Vulcanizates Filled with Silica (실리카로 보강된 천연고무 가황물의 가교 밀도 변화에 가황촉진제 함량이 미치는 영향)

  • Choi, Sung-Seen;Nah, Changwoon
    • Journal of Adhesion and Interface
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    • v.3 no.2
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    • pp.30-39
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    • 2002
  • The effect of cure accelerator content on the change in crosslink density by thermal aging was studied for silica-filled natural rubber (NR) vulcanizates. Influence of silane coupling agent was also investigated. N-tert-Butyl-2-benzothiazole sulfenamide (TBBS) and bis-(3-(triethoxysilyl)-propyl)-tetrasulfide (TESPT) were used as a cure accelerator and a silane coupling agent, respectively. The crosslink density increased by thermal aging and the increasing level became larger as the aging temperature increased. The degree of crosslink density change of the vulcanizates without the silane coupling agent was larger than that of the vulcanizates containing the silane coupling agent. For the vulcanizates silane coupling agent, the activation energy for the crosslink density change decreased with increase of the cure accelerator content in the vulvanizate.

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