Lee J.,Sejong University |
Oh J.-I.,Land and Housing Institute |
Ok Y.S.,Kangwon National University |
Kwon E.E.,Sejong University
Energy | Year: 2017
This study systematically investigates simultaneous genuine roles of CO2 in pyrolysis process by comparing the susceptibility of pyrolysis of various biomass feedstocks (spent coffee ground, oak wood, corn stover, macroalgae, microalgae, cellulose, hemicellulose, and lignin) to CO2: 1) the enhanced thermal cracking of volatile organic carbons (VOCs) evolved from the thermal decomposition of biomass and 2) the direct reaction between VOCs and CO2. The identified roles of CO2 led to the enhanced generation of CO and the subsequent reduction of condensable tar. Even though the influence of CO2 on pyrolysis of various biomass and coal was universal, it exhibited a different magnitude due to the different susceptibility to CO2. This study also reports that the susceptibility to CO2 was contingent on the lignin content in biomass. © 2017 Elsevier Ltd.
Oh J.H.,Sungkyunkwan University |
Lee E.-J.,Sungkyunkwan University |
Oh J.I.,Land and Housing Institute |
Kim J.-O.,Hanyang University |
Jang A.,Sungkyunkwan University
Environmental Science and Pollution Research | Year: 2015
As cities are becoming increasingly aware of problems related to conventional mobile collection systems, automated pipeline-based vacuum collection (AVAC) systems have been introduced in some densely populated urban areas. The reasons are that in addition to cost savings, AVAC systems can be efficient, hygienic, and environmentally friendly. Despite difficulties in making direct comparisons of municipal waste between a conventional mobile collection system and an AVAC system, it is meaningful to measure the quantities in each of these collection methods either in total or on a per capita generation of waste (PCGW, g/(day*capita)) basis. Thus, the aim of this study was to assess the difference in per capita generation of household waste according to the different waste collection methods in Korea. Observations on household waste show that there were considerable differences according to waste collection methods. The value of per capita generation of food waste (PCGF) indicates that a person in a city using AVAC produces 60 % of PCGF (109.58 g/(day*capita)), on average, compared with that of a truck system (173.10 g/(day*capita)) as well as 23 %p less moisture component than that with trucks. The value of per capita generation of general waste (PCGG) in a city with an AVAC system showed 147.73 g/(day*capita), which is 20 % less than that with trucks delivered (185 g/(day*capita)). However, general waste sampled from AVAC showed a 35 %p increased moisture content versus truck delivery. © 2015 Springer-Verlag Berlin Heidelberg
PubMed | Sungkyunkwan University, Hanyang University and Land and Housing Institute
Type: Journal Article | Journal: Environmental science and pollution research international | Year: 2016
As cities are becoming increasingly aware of problems related to conventional mobile collection systems, automated pipeline-based vacuum collection (AVAC) systems have been introduced in some densely populated urban areas. The reasons are that in addition to cost savings, AVAC systems can be efficient, hygienic, and environmentally friendly. Despite difficulties in making direct comparisons of municipal waste between a conventional mobile collection system and an AVAC system, it is meaningful to measure the quantities in each of these collection methods either in total or on a per capita generation of waste (PCGW, g/(day*capita)) basis. Thus, the aim of this study was to assess the difference in per capita generation of household waste according to the different waste collection methods in Korea. Observations on household waste show that there were considerable differences according to waste collection methods. The value of per capita generation of food waste (PCGF) indicates that a person in a city using AVAC produces 60% of PCGF (109.58g/(day*capita)), on average, compared with that of a truck system (173.10g/(day*capita)) as well as 23%p less moisture component than that with trucks. The value of per capita generation of general waste (PCGG) in a city with an AVAC system showed 147.73g/(day*capita), which is 20% less than that with trucks delivered (185g/(day*capita)). However, general waste sampled from AVAC showed a 35%p increased moisture content versus truck delivery.
Lee H.H.,Dongyang University |
Chun Y.S.,Land and Housing Institute
Advanced Materials Research | Year: 2014
To improve the seismic performance of existing residential buildings, strengthening methods for T-shaped walls are evaluated through the performance tests. Almost damaged three specimens are strengthened by aramid fiber sheet and additional reinforcement. Cyclic lateral loads are applied to the top of the specimen with constant axial load. From these, strengthened wall by aramid fiber sheet and additional reinforcement shows the almost 100% strength and deformation capacity recovery comparing the undamaged wall. For the convenience of wall strengthening method in a residential state, using of aramid fiber sheet is recommended from this performance test results. © (2014) Trans Tech Publications, Switzerland.
Cho S.,Land and Housing Institute
A/Z ITU Journal of the Faculty of Architecture | Year: 2011
After World War II, Seoul and Tokyo had experienced similar urban problems as part of their rapid urbanization and had been developed western planning systems to modernize their urban structures. Seoul and Tokyo had very similar planning schemes for redevelopment, which consisted of legal urban redevelopment projects and subsidies under the Urban Redevelopment Law. The differences in their government operations system and application of development tools caused differences in their urban structures. This article describes each government's efforts and legal systems to illustrate the spatial transform of central areas in Seoul and Tokyo using documentary research and GIS data. This article is intended to address implications on the downtown redevelopment policies of Seoul and Tokyo. And to conclude, 2 Asian mega cities have lost many traditional urban structures under legal redevelopment project until 1990s. Fortunately their planning schemes are changing by making them aware of how redevelopment projects should make conserve traditional urban structures.
Chun Y.S.,Land and Housing Institute |
Chang K.K.,Korea University
Magazine of Concrete Research | Year: 2016
Special reinforced concrete coupling beams in high-seismic-risk regions require specific diagonal bundled reinforcement details that must be strictly followed to ensure proper structural performance. However, when these details are applied to coupled shear wall structures, the coupling beams' width must match the width of the walls, resulting in a complicated rebar layout and difficulty in on-site installation. Especially when applied with special shear wall structures, the joint between the coupling beam and the shear wall results in extremely complex reinforcement details that are almost impossible to install on site. With a view to overcoming such problems, this paper evaluates and reports on seismic resistance performance tests performed on coupling beams with a single diagonal reinforcement bar together with headed bars (DHB) reinforcement details, as a proposed alternative solution. Test results show that the test specimen HB75, in which the headed bars substituted for 75% of the capacity of the diagonal reinforcing bundled bars, had superior ductility and energy dissipation capability, as well as lower strength and stiffness degradation compared to other test specimens. Thus, this research indicates that the headed bars can be a practical alternative to hoops of diagonal bundled bars for confining concrete in coupling beams.
Kim Y.-R.,University of Nebraska - Lincoln |
De Freitas F.A.C.,Stress Engineering Services |
Jung J.S.,Land and Housing Institute |
Sim Y.,Land and Housing Institute
Construction and Building Materials | Year: 2015
This paper presents an experimental test method incorporated with a cohesive zone model to characterize viscoelastic fracture damage of asphalt binders and mastics. The testing presented herein is specifically aimed at identifying rate-dependent, non-constant fracture characteristics of ductile asphalt binders and mastics. Test results that are dependent on materials and specimen geometry such as the film thickness of asphalt binder/mastic are presented. The testing results were then incorporated with a viscoelastic cohesive zone model to identify the material-specific damage evolution characteristics and its mechanical impacts on the overall performance of asphalt mixtures by conducting computational microstructure model simulations. Test results and subsequent microstructure model simulations clearly indicate the significance of component-level material properties and their linkage to mixture performance. The experimental protocol incorporated with the cohesive zone model presented in this paper are expected to provide an efficient tool to evaluate damage-induced mechanical performance of mixtures with small-scale material properties. © 2015 Elsevier Ltd.
Lee K.,Land and Housing Institute |
Lee T.,Korea Land and Housing Corporation
2011 7th Asia-Pacific International Conference on Lightning, APL2011 | Year: 2011
This paper verified the electrical continuity of steelwork and tested the endurance of the steel bars' connection for lightning current in reinforced concrete apartments. It was proven that the steelwork in reinforced concrete apartment has electrical continuity with low resistance(below than 0.2 Ω. Also the installation of the steel bars as down-conductor must be very carefully implemented since it was proven that a poor connection between two reinforcement bars can easily cause serious damage of the concrete even with impulsive current of 50kA, 10/350 μs. © 2011 IEEE.
Lee J.-S.,The Seoul Institute |
Nam J.,University of Seoul |
Lee S.-S.,Land and Housing Institute
International Journal of Sustainable Transportation | Year: 2014
This study examines the impacts of the built environment measures based on two geographic scales, i.e., traffic analysis zone and one quarter-mile buffer on individual mode choice in the Houston metropolitan area. It is confirmed that they have significant impacts on mode choice in varying degrees. The models including the buffer-based measures are more reasonable than those with conventional zone-based variables for both home-based work and other trips. Finally, the elasticity estimates suggest the built environments are undervalued in the conventional transportation practices. Both land use and transport pricing measures should be considered complementary to control the demand for driving. © 2014 Copyright Taylor and Francis Group, LLC.
Chun Y.S.,Land and Housing Institute |
Chang K.K.,Seoul National University of Science and Technology
Applied Mechanics and Materials | Year: 2013
Damage detection of a structure has drawn much attention in the aspect of maintenance and safety. In these aspects, vibration characteristics of a building have been constantly used in order to obtain a damage index of the whole building, but practical methodologies have not been presented yet. This study proposes a practical methodology to detect damage of a structure by using only the first natural frequency and mode shape of a building. The validity of the proposed methodology has been verified by experiments and numerical analyses. A result of verification confirms degree and location of damage may be detected with a relatively small error by the proposed methodology. © (2013) Trans Tech Publications, Switzerland.