• Title/Summary/Keyword: early-strength

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An Experimental Study on the Effect of Reduced Slag and Gypsum on Concrete at Low Temperature(-5℃) (저온(-5℃)에서의 환원슬래그 및 석고가 콘크리트에 미치는 영향에 관한 실험적 연구)

  • Kim, Hyeong-Cheol;Choi, Hyun-Kuk;Min, Tae-Beom;An, Dong-Hee;Choi, Si-Hyun;Lee, Han-Seung
    • Journal of the Korea Institute of Building Construction
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    • v.17 no.3
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    • pp.279-285
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    • 2017
  • In this study, the development of concrete preventing initial frost damage and durability about that were evaluated by using anti-aging agent and admixture(reduced slag). As a result of experiment, initial hydration heat was increased by $C_{12}A_7$ of reduced slag components but it was not effective to development of strength. Also fluidity decreased with increasing replacement of reduced slag. This suggested that fluidity was low by rapid setting due to absent of gypsum in reduced slag components. In case of CR2G specimen that added 4% gypsum, the flow ability was higher than plain. It is considered that concrete developed using reduced slag should use $SO_3$. Result of durability experiments, the durability decreased with increasing replacement amount of reduced slag.

The change of East Asian Monsoon to $CO_2$ increase

  • Kripalani, R.H.;Oh, J.H.;Chaudhari, H.S.
    • The Korean Journal of Quaternary Research
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    • v.20 no.1 s.26
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    • pp.9-27
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    • 2006
  • The East Asian (China, Korea and Japan) summer monsoon precipitation and its variability are examined from the outputs of the 22 coupled climate models performing coordinated experiments leading to the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4) following the multi-model ensemble (MME) technique. Results are based on averages of all the available models. The shape of the annual cycle with maximum during the summer monsoon period is simulated by the coupled climate models. However, models fail to simulate the minimum peak in July which is associated with northward shifts of the Meiyu-Changma-Baiu precipitation band. The MME precipitation pattern is able to capture the spatial distribution of rainfall associated with the location of the north Pacific subtropical high and the Meiyu-Changma-Baiu frontal zone. However precipitation over the east coast of China, Korea-Japan peninsular and the adjoining oceanic regions is underestimated. Future projections to the radiative forcing of doubled $CO_2$ scenario are examined. The MME reveals an increase in precipitation varying from 5 to 10 %, with an average of 7.8 % over the East Asian region at the time of $CO_2$ doubling. However the increases are statistically significant only over the Korea-Japan peninsula and the adjoining north China region. The increase in precipitation may be attributed to the projected intensification of the subtropical high, and thus the associated influx of moist air from the Pacific to inland. The projected changes in the amount of precipitation are directly proportional to the changes in the strength of the subtropical high. Further a possible increase in the length of the summer monsoon precipitation period from late spring through early autumn is suggested.

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Linkage the Development Strategy of Local Government to Spatial Decision Support System (지자체 발전전략과 공간적 의사결정지원체계의 연계 방안 연구)

  • Park, Ji-Man;Hwang, Chul-Sue
    • Journal of the Korean association of regional geographers
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    • v.15 no.5
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    • pp.671-687
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    • 2009
  • This paper aims to link the development strategy of a local government(Guri-si, Kyunggi-do) to a spatial decision support system that is in the early stages of implementation and testing. Spatial Decision for a local governmental authority typically involves multiple stakeholders. To any specific regional problem, stakeholders often have various levels of knowledge and experiences about it, that yield conflicting views. In this point of view, the enhanced access to information can bring the decision process to solve the problem throughout more public participation. Recently, Urban development study was required to improve the decision making of public participation form. This study aim to investigate an analysis local government of Guri-si, can be supported as the suggestion of decision making system. Guri-si has been argued that it would improve citizen's life quality intent theme 'by historical tourism in general dimension' promote region identity, environment friendly and transportational strength, by reflecting various plan of urban development and it executed strategy. There are increasing interest in citizen participation and practical using of policy decision making to respond to uncertain environment and systematic exploration of local government. Focused on the contents of public participation decision making, it is important to investigate how to analysis urban development strategy and geographic information relationship for useful. The paper concludes with a discussion of current issues encountered during development and implementation of spatial decision making(or support) system for the local administrative authority.

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The Effects of Negative Pressure and Drain Spacing in the Horizontal Method for an Early Settlement of Dredged and Filled Grounds (해안준설매립토의 조기안정을 위한 수평배수공법에서 부압과 배수재 배치간격의 영향)

  • 김수삼;한상재;김병일;김정기
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.15 no.1
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    • pp.1-10
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    • 2003
  • In this paper, the laboratory test results with middle-sired ,soil box test in modeling the in-situ installing of horizontal drains are discussed the estimation of the optimum negative pressure. The test was carried out in the different vacuum pressure conditions together with the measurement for the settlement and volume change of drained water by the installed drains during the consolidation process. After the test, the water content was measured to both directions of lateral distance from the drain and depth of the soil, to find out the distribution of ground improvement and strength enhancement. From the analysis on the distribution of water content, the gradual application of vacuum pressure to higher level by pre-determined stages starting from low vacuum pressure is found to be effective and desirable. In the comparison of the degrees of consolidation with elapsed time, the calculated value by the prediction method based on the Barren's conventional theory showed a good agreement with the measured value. With this, It is positively considered that the applicability of the prediction method based on Barren's theory to the practical design of horizontal drains can be justified such as in the calculation of drain spacing and consolidation period.

Ligament Reconstruction for Subluxation of the Trapeziometacarpal Joint of the Thumb (무지의 대능형중수간 관절의 아탈구에 대한 인대 재건술)

  • Park Jin Soo;Chung Yung Khee;Yoo Jung Han;Na Kyong Soo
    • Journal of Korean Orthopaedic Sports Medicine
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    • v.3 no.2
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    • pp.134-140
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    • 2004
  • Purpose: The reconstructive surgery of the anterior oblique ligament has been recommended for patients with unstable carpometacarpal joints. We reviewed retrospectively the functional results of two patients who had been treated by6 using a harvested portion of the tendon of flexor carpi radialis as a substitute for the anterior oblique ligament. Materials and Methods: In two patients with a instability of the trapeziometacarpal joint because of a rupture of the anterior oblique ligament, reconstruction was carried out using a slip of the tendon of flexor carpi radialis and the patients had been followed up for two years. Results: The results after a follow-up of two years that both of them had significant relief from pain and symptoms. The mean grip strength recovered to 90$\%$ of the controlateral side. patients felt that they had subjective improvement and would have undergone the operation again. Conclusion: Increased awareness of this lesion can lead to an early and clear diagnosis, so that the patient may be advised adequately.

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Analysis of Crash Load in Crash Impact Test for Fuel Tank of Rotorcraft (항공기용 연료탱크 Phase I 충돌충격시험 충격하중 분석)

  • Kim, Hyun-gi;Kim, Sung Chan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.6
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    • pp.3736-3741
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    • 2015
  • Crash impact test is conducted to verify the crashworthiness of fuel tank. Success of the crash impact test means the improvement of survivability of crews by preventing post-crash fire. But, there is a big risk of failure due to huge external load in the crash impact test. The failure of crash impact test can result in serious delay of a entire rotorcraft development because of the design complement and re-production of the test specimens requiring a long-term preparation. Thus, the numerical simulations of the crash impact test has been required at the early design stage to minimize the possibility of trial-and-error in the real test. Present study conducts on the numerical simulation of phase I crash impact test using SPH supported by crash simulation software, LS-DYNA. Test condition of MIL-DTL-27422 is reflected on analysis and material data is acquired by specimen test of fuel cell material. As a result, the crash load on the skin material, overlap area and metal fitting is estimated to confirm the possibility of acquisition of the design load for the determination of the overlap area and adhesive strength.

Modeling Study on Deterioration of Stone Monuments Constructed with Silicate Rock by Acid Rain (규산염질 암석으로 구성된 석조문화재의 산성비에 의한 손상 임상연구)

  • Do, Jin-Young;Cho, Hyen-Goo
    • Journal of the Mineralogical Society of Korea
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    • v.23 no.1
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    • pp.63-71
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    • 2010
  • The artificial rains having different pH and weathering simulation test were performed for Gyeongju Namsan granite and dacitic tuff to predict the role of acid rain in the deterioration of stone monuments located in Gyeongju area. The pH 4.0 rain reacted with the fresh granite showed near neutral pH at the early stage due to the hydrolysis of minerals in the rock surface. But the pH changed back to the initial pH in the later stage. On the other hand, the pH 5.6 rain showed the neutral pH for a longer time than the experiment with pH 4.0 rain, reflecting slower reaction of minerals due to the weaker acidity. When the pH 5.6 rain reacted with the weathered granite, the water showed neutral pH longer than the case of the fresh granite. The similar tendencies were observed in the experiment of dacitic tuff, except that the pH 4.0 rain reacted with dacitic tuff took a longer time to go back to the initial pH as compared with the case of granite. These results may due to the differences in mineral composition and texture of two rocks. Dacitic tuff contains more fine-grained or glassy groundmass than granite and is more reactive with weaker acid rain. It was predicted that the weight loss and strength decrease rate of dacitic tuff would be approximatetly twice relative to those of granite in the same experimental environment.

A Study on Continuous Monitoring Reinforcement for Sales Audit Using Process Mining Under Big Data Environment (빅데이터 환경에서 프로세스 마이닝을 이용한 영업감사 상시 모니터링 강화에 대한 연구)

  • Yoo, Young-Seok;Park, Han-Gyu;Back, Seung-Hoon;Hong, Sung-Chan
    • Journal of Internet Computing and Services
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    • v.17 no.6
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    • pp.123-131
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    • 2016
  • Process mining in big data environment utilize a number of data were generated from the business process. It generates lots of knowledge and insights regarding implementation and improvement of the process through the event log of the company's enterprise resource planning (ERP) system. In recent years, various research activities engaged with the audit work of company organizations are trying actively by using the maximum strength of the mining process. However, domestic studies on applicable sales auditing system for the process mining are insufficient under big data environment. Therefore, we propose process-mining methods that can be optimally applied to online and traditional auditing system. In advance, we propose continuous monitoring information system that can early detect and prevent the risk under the big data environment by monitoring risk factors in the organizations of enterprise. The scope of the research of this paper is to design a pre-verification system for risk factor via practical examples in sales auditing. Furthermore, realizations of preventive audit, continuous monitoring for high risk, reduction of fraud, and timely action for violation of rules are enhanced by proposed sales auditing system. According to the simulation results, avoidance of financial risks, reduction of audit period, and improvement of audit quality are represented.

Changes in the Concept of Disability and its Implications for Social Work Practice (장애개념의 변화와 사회복지실천 현장 함의)

  • Kim, Yong-Deug
    • Korean Journal of Social Welfare
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    • v.51
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    • pp.157-182
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    • 2002
  • This study attempts to identify the changes in social reactions to disabilities in general, and to research the contextual implication of these changes in social work practice in Korea. In the early years after the Industrial Revolution, disability was conceived as social unfitness and it was assumed that the cause and responsibility could be attributed to people with disabilities. But, in the midst and late 20th century, social responsibility for people with disabilities was argued and generally accepted. As the results of these changes, conceptual models explaining disabilities have changed gradually; there has been a transition, so called, from individual model to social model. In a similar vein, WHO has refined the definition and classification of disability. Related to these changes, social welfare service paradigm for people with disabilities has shifted. This paradigm shift can be explained with the perspective of strength approach, empowerment approach, case management and independent living model. In Korea, 1998 Act on welfare for people with disabilities meant that social service for the disabled were categorized with, namely, residential service, community rehabilitation service and vocational rehabilitation service. Recently, the extent of these services has been rapidly broadened. In these situation, this study researched to identify the implications on social work practice in the context of changes in social response, conceptual model, definition and also service paradigm. Such as the followings are enumerated for the implications: disabled person's participation in assessment process, development of assessment tools focusing on social and environmental perspectives, reinforcement of information service helping self-determination, supporting on formal and informal helping network, expanding self-help programs and, finally, a shift from displacement model to support model.

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Development Stages and Characteristics of Place-Based Industry-Academic Cooperation Projects: The Case of Universities Participating in the LINC+ Project (대학-지역 연계형 산학협력 사업의 발전단계와 특성: LINC+사업 참여대학을 중심으로)

  • Lee, Jong-Ho;Jang, Hoo-Eun
    • Journal of the Economic Geographical Society of Korea
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    • v.22 no.1
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    • pp.96-109
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    • 2019
  • As the role of universities as a civic university contributing to regional development has been emphasized, industry-academic cooperation projects are increasingly focused on quadruple helix interactions of university, government, business and civic society. Drawing upon focus group interviews, we divided place-based industry-academic cooperation projects into four different types and stages of development, according to two indicators of network participation and network strength. Although the proportion of projects that were in the early stages of development was overwhelmingly high, some universities developed a close cooperative system with the local community to enhance the effectiveness of the industry-academic cooperation projects and to implement them in an advanced stage. These findings suggest that the LINC+ project, which has been criticized for its policy effectiveness, will not only contribute to enhancing policy effectiveness through place-based projects but also enhance the role of universities as the main body of regional innovation.