• 한국연소학회:학술대회논문집
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• 한국연소학회 2004년도 제28회 KOSCO SYMPOSIUM 논문집
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• pp.227-234
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• 2004

For gaseous fuel combustion with inherent $CO_2$ capture and low NOx emission, chemical-looping combustion(CLC) may yield great advantages of savings of energy to $CO_2$ separation and suppressing the effect on environment. In chemical-looping combustor, fuel is oxidized by metal oxide medium (oxygen carrier particle) in a reduction reactor. Reduced particles are transported to oxidation reactor and oxidized by air and recycled to reduction reactor. The fuel and the air are never mixed, and the gases from reduction reactor, $CO_2$ and $H_2O$, leave the system as separate stream. The $H_2O$ can be easily separated by condensation and pure $CO_2$ is obtained without any loss of energy for separation. The purpose of this study is to demonstrate inherent $CO_2$ separation and no NOx emission and to confirm high $CO_2$ selectivity, no side reaction (i.e., carbon deposition, hydrogen generation) by continuous reduction and oxidation experiment in a 50kWtb chemical-looping combustor. NiO/bentonite particle was used as a bed material and $CH_4$ and air were used as reacting gases for reduction and oxidation respectively.

• KIEAE Journal
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• 제13권6호
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• pp.113-120
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• 2013

Many countries over the world have taken many discussions and endeavors on environmental improvements of energy savings and greenhouse gas emission reductions for solving global climate change problems. In Korea, pre-considerations of environment-conscious factors in buildings have been taken to be critical with new constructions and renovation markets. In this situation, the Korean Green Building Certification(KGBC) system to induce the diffusion of sustainable buildings was introduced in 2002 and developed as an improved version of the G-SEED(Green Standard for Energy and Environmental Design) system in 2013 after major revisions. This research examines the importance of assessment criteria on apartment buildings to certify green buildings using the AHP(Analytic Hierarchy Process) method and suggests a new direction on certification assessment standards from the AHP result. In order to apply the AHP method, the survey via e-mail was conducted to design staffs in domestic architectural firms. As a result, assessment criteria such as ecological environment, indoor environment, and energy & environment pollution among 7 main ones proved to be important on assessing the G-SEED system for apartment buildings, while criteria such as land use & transportation, material & resource, water circulation management, maintenance management did relatively unimportant.

• 소성∙가공
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• 제24권5호
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• pp.340-347
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• 2015

Multi-pass shape drawing is used to manufacture long products of arbitrary cross-sectional shapes. This process allows smooth surface finishes and closely controlled dimensions of the cross-sectional shape. Tube shape drawing for hollow type products provides material savings and weight reduction. The intermediate die shapes are very important in multi-pass tube shape drawing. In the current paper, the design method for the intermediate dies in a tube shape drawing process is developed using a die offset for corner filling (DOCF) method. Underfill defects are related to the radial velocity distribution of each divided section in the deformation zone. The developed intermediate die shape design was applied to the two-pass tube shape drawing with fixed mandrel for manufacturing a hollow linear motion (LM) guide rail. The proposed design method led to uniform and steady metal flow at each divided section. FE-simulations and experiments were conducted to validate the effectiveness of the proposed method in multi-pass tube shape drawing process.

• 농촌지도와개발
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• 제14권2호
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• pp.417-436
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• 2007

The purpose of this study was to prepare for developing rural house remodeling techniques utilizing the traditional residence factor. The study was carried out through both literature research and on-site research. The traditional residence space factors were identified through literature research and on-site research was carried out through analysis of the rural house remodeling cases. The results of this study was as follows ; 1) Traditional space factors were derived by literature research i. e. space arrangement (topography, direction, plane arrangement), exterior factors; walls, madang, interior factors; roofs, ondol, floors, colours. 2) The traditional residence factor utilizations of remodeling were applied a result through investigation case and analysis. Five rural houses in Namsa village, Danseong-myeon, Sangcheong-gun, Gyeongsangnam-Do were analyzed as remodeling cases including traditional residence factors. There were limitation of budget problems and material selection in the traditional residence factor utilizations of remodeling. The researchers have chosen target rural houses which applied for traditional residence factors to remodel the rural houses, and the most important factor to consider was harmony with rural unique characteristics. The researchers suggested considerations should be placed on development with energy savings and convenience in rural house remodelling.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.561-564
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• 2004

Steel sheet pile can be alternative material for bridge abutment for. The steel sheet pile bridge abutment is new and replacement bridge abutment due to its aesthetically attractive and cost effective. Use of embedded steel sheet piling brings savings in dead load, provides a compliant retaining wall, and permits speedier construction. In addition, for replacement bridge projects, traffic interruption can be minimized. It is hoped that this study will encourage designers and constructors to consider a steel substructure option more frequently during the conceptual and preliminary design phases of projects and thereby to take advantage of the potential to construction more efficiently. In this paper, an analysis of stress and strain for steel sheet pile bridge abutment was conducted. From the analysis results, the stress and strain characteristics of steel sheet pile bridge abutment with variations of steel sheet pile parameters is suggested.

• KIEAE Journal
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• 제13권4호
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• pp.63-68
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• 2013

On the electricity consumption in Korea, the lighting sector takes about 17% of annual total electricity consumptions. In the midst of higher interests on energy conservation measures, design and choice of energy-saving lighting fixtures have been more important. With growth of technology-intensive industries like advanced material, semiconductor, and biotechnology from the 1980s, needs for clean room and thus illumination at clean rooms have been increased. In this paper, development, specification, and features of a Teardrop LED(hereinafter TD LED) lighting fixture as replacement of Teardrop florescent lighting one that has been popularly installed at clean rooms were presented. Also we performed the economic analysis of return on investment(ROI) about energy savings by the installation of the TD LED lighting fixture at a new-built clean room. The economic analysis showed that the new-developed TD LED lighting fixture would be able to withdraw the initial installation cost within 4 years. Lastly, improvement directions and development plans of the next TD LED lighting fixture for wider applications at clean rooms were described.

• Architectural research
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• 제16권3호
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• pp.93-100
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• 2014

Existing BIM(Building Information Modeling) based energy evaluation tools cannot be utilized enough for the potential performance of BIM because most of them have not provided the integrated model for energy evaluation, assessment of the material, cost of the construction, and so on. This research aims to propose and develop a new application, EcoBIM, to support an integrated evaluation of the energy and cost efficiencies of the design alternatives within the design process. The proposed application functions as a BIM-based evaluation system that calculates energy-savings performance as well as the construction cost of the alternatives at the design stage. This study mainly focuses on the possibilities of developing the proposed technology. We also suggest an advanced design process using the proposed system, corresponding to changes of national regulations in Korea. This study deduce that EcoBIM can allow architects to make suitable decisions regarding energy- and cost-efficient designs. The proposed design process will allow architects not only to check the eco-friendly performance of design alternatives but also predict the operation cost in a certain period in the future. EcoBIM can prevent large-scale design changes required to obtain environmental certification and enable the owner to make an informed decision about the initial investment of construction according to the result of the analysis of the energy requirement at the design stage.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.231-237
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• 2000

A15052/AFRP laminates were developed principally to obtain a material with good fatigue strength, in which possible cracks would grow very slowly. Weight savings of more than 30% should be attainable in practice. Also, the crack bridging fibers could still was carry a significant part of the load over the crack, thus the COD and stress intensity factor was reduced at the crack tip. A15052/ AFRP laminates consists of three thin sheets of 5052-H34 aluminum alloy and two layers of [0] unidirectional aramid fiber prepreg. The cyclic-bending moment test was investigated based on applying the five kinds of bending moments. The size of the delamination zone produced between 5052-H34 aluminum alloy sheets and fiber-adhesive layers was measured from ultrasonic C-scan pictures taken around the fatigue crack. In addition, the relationship between the cyclic-bending moment and the delamination zone size was studied and the effect of fiber bridging mechanism was also considered.

• 한국세라믹학회지
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• 제26권4호
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• pp.575-582
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• 1989

The effects of raw material feeding procedures and gelation temperatures on zeolite synthesis are investigated. Thus, the synthesis of zeolite 4A from sodium aluminate and sodium silicate solutions is chosen as a model reaction, for which equi-molar hydrogelation is performed with variation of feeding procedures and gelation temperatures. The formation of crystal nuclei, often being referred to as precursors, is induced under different conditions, the variation being examined by means of viscosity and water contents. The final products of zeolite 4A are evaluated by XRD, SEM morphology, particle size analysis and cation exchange capacity. Evidence shows that the viscosity of the initial products and their water contents are markedly influenced by the feeding methods of the reactant materials and by the gelation temperature. Further, it is found that the gelation at an elevated temperatures near 7$0^{\circ}C$ can be made possible through modification of mixing procedures. This provides convenient means of controlling the particle size of the final products. In this regard, a continuous flow-type mixing technique is proposed, which is demonstrated to be superior to the conventional batch-type mixings. The significance of this finding may lie in savings of equipment as well as energy costs, especialy on a large scale commercialization of zeolite production.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2009년도 추계 학술논문 발표대회
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• pp.31-34
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• 2009

Large outrigger elements tie the concrete core to perimeter columns, significantly increasing the building's lateral stiffness as well as its resistance to overturning due to wind. The outriggers are deep elements, and large tie forces are resisted by top and bottom heavy longitudinal reinforcing and vertical ties. To reduce construction costs, all primary reinforcing bars in outrigger levels are SD500. Further, concrete strengths of 80MPa have been specified for outrigger elements. However, the reductions in the amount of concrete and reinforcement steel are more increased in tall building. With these backgrounds, 80MPa high strength concrete outrigger system using post tension method is developed. Significant economic savings can be made by reducing the element sizes and material content. The developed outrigger system is designed using strut-and-tie models. In addition, four 1/4-scale test specimens were selected from the same prototype structure. The results from the tests are confirmed that the structural behaviors of the developed outrigger member have better capacities than those of a conventional method.