• Clean Technology
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• v.27 no.4
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• pp.332-340
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• 2021

With the recent reinforcement of emission standards, it is necessary to make efforts to reduce NOx from air pollutant-emitting workplaces. The NOx reduction method mainly used in industrial facilities is selective catalytic reduction (SCR), and the most commercial SCR catalyst is the ceramic honeycomb catalyst. This study was carried out to reduce the NOx emitted from steel plants by applying De-NOx catalyst coated on metallic monolith. The De-NOx catalyst was synthesized through the optimized coating technique, and the coated catalyst was uniformly and strongly adhered onto the surface of the metallic monolith according to the air jet erosion and bending test. Due to the good thermal conductivity of metallic monolith, the De-NOx catalyst coated on metallic monolith showed good De-NOx efficiency at low temperatures (200 ~ 250 ℃). In addition, the optimal amount of catalyst coating on the metallic monolith surface was confirmed for the design of an economical catalyst. Based on these results, the De-NOx catalyst of commercial grade size was tested in a semi-pilot De-NOx performance facility under a simulated gas similar to the exhaust gas emitted from a steel plant. Even at a low temperature (200 ℃), it showed excellent performance satisfying the emission standard (less than 60 ppm). Therefore, the De-NOx catalyst coated metallic monolith has good physical and chemical properties and showed a good De-NOx efficiency even with the minimum amount of catalyst. Additionally, it was possible to compact and downsize the SCR reactor through the application of a high-density cell. Therefore, we suggest that the proposed De-NOx catalyst coated metallic monolith may be a good alternative De-NOx catalyst for industrial uses such as steel plants, thermal power plants, incineration plants ships, and construction machinery.

• Research in Mathematical Education
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• v.7 no.1
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• pp.41-58
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• 2003

This study firstly examined 18 prospective secondary mathematics teachers' understanding of the nature of definitions and the use of the dynamic geometry software Sketchpad to not only improve their understanding of definitions, but also their ability to define geometric concepts themselves. Results indicated that the evaluation of definitions by accurate construction and measurement enabled students to achieve a better understanding of necessary and sufficient conditions, as well as the ability to more readily find counter-examples, and to recognize uneconomical definitions, and improve them.

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.939-942
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• 1998

This paper presents the process on the construction for the remote distribution pole transformer monitoring system. Especially, this system uses CATV cable as communication media which is located in KEPCO's main distribution line. It has four major components such as sensor for measuring secondary voltage and currents of distribution transformer, RF modem for data modulating/de-modulating, communication media for sending/receiving of data, and pc server for monitoring the results of sensing or computing information. This paper also describes the configuration of these each component's configuration and its functions.

• The Korean Journal of Ecology
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• v.25 no.1
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• pp.9-17
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• 2002

Human activities greatly affect the environment causing its degradation. Urban development and road networks construction cause main impacts on ecosystems and particularly on vegetation cover: road constructions induce complete degradation of the vegetation cover and often leaves a hare land, sometimes without even a soil cover. Reconstitution of vegetation cover is necessary to limit superficial erosion and land slipping on the road, towards a reintegration of the site in the neighbouring landscape. Many approaches have been studied over the last 30 years aiming at this reconstitution of vegetation cover. At frost, the main purpose of land reclamation was to create a new ecosystem. At this time, the environment created was rather a "garden" with a new soil adapted to the plantation of "decorative" species. Then, in early 90′s many studies on the restoration ecology concept rather focused on adapting the vegetation to the existing conditions on the site, as in a side road embankment for example. Nowadays, we notice a large tendency towards the use of such adapted native species instead of industrially produced seeds. In southern France, our team have led research on the potentials of those local species for their use in revegetation processes with hydro-seeding. We therefore developed an approach combining the use of different types of species: Industrially produced, native and wild cultivated species. This method integrates the benefits of using available low costing seeds that are already used on large scale projects with better adapted species, issued form the cultivation of native species and seed production for their use on smaller scale and more costly but more effective results. The use of wild cultivated species seeds was developed in order to limit the cost and reduce harsh natural seed withdrawal in the natural environment In the case of the use of native species. Besides, the use of such seeds allowed a larger geographical scale of use than with local native seeds. In addition, our team began two years ago a research project in Lebanon aiming at the Introduction and development of the revegetation techniques in Lebanon. In fact, this country bared since 20 years the consequences of urban pressure on its environment especially by the development of quarries and road networks. Therefore, pioneer work is necessary to aim at the adaptation of these techniques to the local environment.

• Journal of the Korea Institute of Building Construction
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• v.12 no.1
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• pp.122-132
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• 2012

Establishing a success model of a specific information system is critical to understanding the mechanism of IS success, the various dimensions of IS performance, and the factors and their causal relations in IS success. As one of the key IT applications, the project management information system (PMIS), particularly the web-based PMIS (Web-PMIS), has played a significant role in construction management processes in Korea. However, there have been few research attempts made to construct a Web-PMIS success model. This study primarily aims to propose a Web-PMIS success model based on DeLone and McLean's IS success model, and to discuss whether or not the D&M IS success model can be applied to the construction Web-PMIS. A questionnaire was sent out to Web-PMIS users (construction managers and constructors), and 253 completed questionnaires were received. Through multi-regression analysis, it was confirmed that it is statistically acceptable to apply the D&M IS success model to the Web-PMIS. However, the explanatory power of the model is not sufficient, and some of the model factors are not statistically significant enough. Relying on the statistical analysis results, this study also discusses the development direction for the Web-PMIS success model.

• Korean Institute of Interior Design Journal
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• no.25
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• pp.155-161
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• 2000

'Transparency', which has been an important topic of architectural discourse in the recent past, is playing an even greater role in architectural expression nowadays. The purpose of this study is to define the prevailing conceptions about transparency and to discover the various modes of this design effect in architectural space. By using partial or complete of transparency in a structure, designers are able to express themselves more profoundly. The perception between exterior and interior, transformation of day into night and conditions arising from spatial overlapping create an atmosphere which deepens the quickly of architectural design. Transparency can present as void what in reality is solid. Following the period of de-construction, transparency has asserts itself in late part of the century and transparency can be considered synonymous with modernistic and refers to structure that are optically luminant or pleasant in its simplicity. Along with advancement of climate control, construction and design technologies and new material with versatility should combine to even further the diversity of transparency in architectural expression.

• Geomechanics and Engineering
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• v.15 no.3
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• pp.899-910
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• 2018

Terrace deposits are often encountered in portal areas and tunnels with low overburden. They are challenging to excavate considering their great mechanical and spatial heterogeneity and a very high stiffness contrast within the ground. Terrace deposits are difficult to characterize, considering that samples for laboratory testing are almost unfeasible to obtain, and laboratory tests may not be representative due to scale effects. This paper presents the approach taken for their characterization during the design stage and their posterior validation performed during construction. Lessons learned from several tunnels excavated on terrace deposits on the Bogota-Villavicencio road (central-east Colombia), suggest that based on numerical simulations, laboratory testing and tunnel system behaviour monitoring, an observational approach allows engineers to optimize the excavation and support methods for the encountered ground conditions, resulting in a more economic and safe construction.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.136-141
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• 2000

Concrete has been used for many years as a composite material that has excellent mechanical properties and durability for construction. However, concrete ia a poor electrical conductor, especially under dry conditions. Concrete that is excellent in both mechanical and electrical conductivity properties may have important applications in the electrical, electronic, military and construction industry (e.g for de-icing road from snow). The purpose of this investigation is to improve the electrical conductive of cement mortar preparared with graphite as filler. From the test result, as the ratio of graphite/cement increased, fluidity, fluidity and strength decreased but resistivity decreased. The resistivity of electrical conductive cement mortar is effect by water/cement ratio and water content of specimen. From this study, it is enough to assure the use of graphite as a conductive filler for electrical conducive cement mortar.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2007.04a
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• pp.137-139
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• 2007

Recently, the research on durability of concrete proceed rapidly in the building industry. Deterioration due to do-icing salts occurs in practice in bridge structure, dike, barrier and similar structure. This paper reports the results of effect of chlorides on the freeze-thaw properties of concrete bridge deck in winter. The case fresh water condition where the concrete will receives a freez-thaw effect compared to decrease of durability quotient a lot occurs is a possibility of knowing from brine condition.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10b
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• pp.933-938
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• 2000

Concrete has been used for many years as a composite material that has excellent mechanical properties and durability for construction. However, concrete is a poor electrical conductor, especially under dry conditions. Concrete that is excellent in both mechanical and electrical conductivity properties may have important applications in the electrical, electronic, military and construction industry(e.g. for de-icing road from snow). The purpose of this investigation is to improve the electrical conductive of cement mortar preparared with coke dust, graphite, carbon black and carbon fiber as filler. From the test result, as the content of electrically conductive material increased, fluidity and strength decreased but resistivity decreased. The resistivity of electrical conductive cement mortar is effect by water/cement, and aggregate. Cement mortar containing carbon fiber has the best electrical properties considering strength. From this study, it is enough to assure the use of carbon fiber, carbon black and graphite as a conductive filler for electrical conductive cement mortar.