• Asian Journal of Turfgrass Science
• /
• v.23 no.2
• /
• pp.279-286
• /
• 2009

This study was carried out to utilize the waste heat from office building for turfgrass culture on a roof garden. Heating system had been installed in the middle of soil profile on the turf areas in the garden plots. The results showed that the installation of heating system increased the shoot density, turfgrass quality, coverage rate, and root length compared with the control plots. The surface temperature of heating plots reached at $10.9^{\circ}C$ when the control plot showed $0^{\circ}C$, however, the soil moisture content was decreased 1.9% by the heating system. When the height of the snow accumulation reached over a 15cm, the it took only 4 days to melt out completely, while the height did not changed those period at the control plots. When the water temperature in boiler increased to $60^{\circ}C$ from a proper temperature of $55^{\circ}C$ in turf growth, the desiccation from leaf tip was started to occur caused by drought stress. More detail research should be followed in stress physiology in turf management in roof garden operation.

• Journal of the Korean Geotechnical Society
• /
• v.25 no.2
• /
• pp.45-54
• /
• 2009

The electrical characteristics of soils have been used for investigating soil properties. The purpose of this study is the development and application of the electrical resistivity cone probe (ERCP) for the evelation of the porosity in the field with high precision. The shape of the probe tip is a cone shape to minimize the disturbance during penetration. In addition, the four terminal pair configuration is adopted to minimize the electrical interference. The electrical resistances are continuously measured during penetration of the ERCP using penetration rigs with 0.33 mm/sec penetration rate at Incheon and Busan sites. With the measured resistance profile and electrical resisivity of electrolyte of undisturbed samples, soil porosity profiles are obtained by using Archie's law. The empirical coefficients for the Archie's law are obtained based on the electrolyte extracted from the undisturbed samples. The estimated porosity profiles show similar trends to those of in-situ penetration tests such as SPT, CPT, and DMT. This study suggests that the ERCP may be an effective tool for the porosity estimation in the field with minimum disturbance.

• Structural Engineering and Mechanics
• /
• v.14 no.3
• /
• pp.287-306
• /
• 2002

The assessment of structural performance of transfer structures under potential seismic actions is presented. Various seismic assessment methodologies are used, with particular emphasis on the accurate modelling of the higher mode effects and the potential development of a soft storey effect in the mega-columns below the transfer plate (TP) level. Those methods include response spectrum analysis (RSA), manual calculation, pushover analysis (POA) and equivalent static load analysis (ESA). The capabilities and limitations of each method are highlighted. The paper aims, firstly, to determine the appropriate seismic assessment methodology for transfer structures using these different approaches, all of which can be undertaken with the resources generally available in a design office. Secondly, the paper highlights and discusses factors influencing the response behaviour of transfer structures, and finally provides a general indication of their seismic vulnerability. The representative Hong Kong building considered in this paper utilises a structural system with coupled shear walls and moment resisting portal-frames, above and below the TP, respectively. By adopting the wind load profile stipulated in the Code of Practice on Wind Effects: Hong Kong-1983, all the structural members are sized and detailed according to the British Standards BS8110 and the current local practices. The seismic displacement demand for the structure, when built on either rock or deep soil sites, was determined in a companion paper. The lateral load-displacement characteristic of the building, determined herein from manual calculation, has indicated that the poor ductility (brittle nature) of the mega-columns, due mainly to the high level of axial pre-compression as found from the analysis, cannot be effectively alleviated solely by increasing the quantity of confinement stirrups. The interstorey drift demands at lower and upper zones caused by seismic actions are found to be substantially higher than those arising from wind loads. The mega-columns supporting the TP and the coupling beams at higher zones are identified to be the most vulnerable components under seismic actions.

• Journal of Korean Society for Atmospheric Environment
• /
• v.19 no.6
• /
• pp.701-717
• /
• 2003

The objective of this study was to extensively estimate the air quality trends of the study area by surveying con-centration trends in months or seasons, after analyzing the mass concentration of PM-10 samples and the inorganic lements, ion, and total carbon in PM-10. Also, the study introduced to apply the PMF (Positive Matrix Factoriza-tion) model that is useful when absence of the source profile. Thus the model was thought to be suitable in Korea that often has few information about pollution sources. After obtaining results from the PMF modeling, the existing sources at the study area were qualitatively identified The PM-10 particles collected on quartz fiber filters by a PM-10 high-vol air sampler for 3 years (Mar. 1999∼Dec.2001) in Kyung Hee University. The 25 chemical species (Al, Mn, Ti, V, Cr, Fe, Ni, Cu, Zn, As, Se, Cd, Ba, Ce, Pb, Si, N $a^{#}$, N $H_4$$^{+}$, $K^{+}$, $Mg^{2+}$, $Ca^{2+}$, C $l^{[-10]}$ , N $O_3$$^{[-10]}$ , S $O_4$$^{2-}$, TC) were analyzed by ICP-AES, IC, and EA after executing proper pre - treatments of each sample filter. The PMF model was intensively applied to estimate the quantitative contribution of air pollution sources based on the chemical information (128 samples and 25 chemical species). Through a case study of the PMF modeling for the PM-10 aerosols. the total of 11 factors were determined. The multiple linear regression analysis between the observed PM-10 mass concentration and the estimated G matrix had been performed following the FPEAK test. Finally the regression analysis provided source profiles (scaled F matrix). So, 11 sources were qualitatively identified, such as secondary aerosol related source, soil related source, waste incineration source, field burning source, fossil fuel combustion source, industry related source, motor vehicle source, oil/coal combustion source, non-ferrous metal source, and aged sea- salt source, respectively.ively.y.

• Journal of the Korean Geotechnical Society
• /
• v.17 no.6
• /
• pp.245-255
• /
• 2001

Existing cut-and-cover tunnels are designed regardless of cut-slope under the assumption that the overburden weight of backfill soil acts on tunnel arch and the earth pressure at rest acts on tunnel walls. However, actual earth pressures acting on the tunnel lining depend on open-cut size composed of cut-slope and cut-width, and thus the tunnel lining shows a different structural behavior. This study investigated the effect of cut-slope on structural behavior of the cut-and-cover tunnel lining as follows; Firstly, a comprehensive numerical analysis method using FLAC2D code was used and verified by field measurements of tunnel profile. Secondly, based on the verified numerical analysis technique, earth pressure acting on the lining, and displacement and sectional force developed on the lining were estimated with various shapes of cut-slopes$30^{\circ}\;, 456{\circ},\; 60^{\circ},\; and\;75^{\circ}%). Numerical analysis results indicate that the steeper cut-slope shows the more displacement and moment of the tunnel lining.

• Asian Journal of Atmospheric Environment
• /
• v.5 no.2
• /
• pp.86-96
• /
• 2011

The positive matrix factorization (PMF2) and multilinear engine (ME2) models have been shown to be powerful environmental analysis techniques and have been successfully applied to the assessment of ambient particulate matter (PM) source contributions. Because these models are difficult to apply practically, the US EPA developed a more user-friendly version of the PMF. The initial version of the EPA PMF model does not provide any rotational capabilities; for this reason, the model was upgraded to include rotational functions in the EPA PMF ver. 2.0. In this study, PMF and EPA PMF modeling identified ten particulate matter sources including secondary sulfate I, vehicle gasoline, secondary sulfate II, secondary nitrate, secondary sulfate III, incinerators, aged sea salt, airborne soil particles, oil combustion, and diesel emissions. All of the source profiles determined by the two models showed excellent agreement. The calculated average concentrations of $PM_{2.5}$ were consistent between the PMF2 and EPA PMF ($17.94{\pm}0.30{\mu}g/m^3$ and $17.94{\pm}0.30\;{\mu}g/m^3$, respectively). Also, each set of estimated source contributions of the PMF2 and EPA PMF showed good agreement. The results from the new EPA PMF version applying rotational functions were consistent with those of PMF2. Therefore, the updated version of EPA PMF with rotational capabilities will provide more reasonable solutions compared with those of PMF2 and can be more widely applied to air quality management.

• Journal of Korean Society for Atmospheric Environment
• /
• v.17 no.2
• /
• pp.119-131
• /
• 2001

A total of 328 ambient PM-10 samples was collected by a PM-10 high volume air sampler during the periods of February 1997 to February 1999 from Kyung Hee University at Suwon Campus. The samples were analyzed for their bulk chemical compositions(Cu, Fe, Pb, Zn, Al, $Na^{+}$, $NH_{4}^{+}$, $K^{+}$, $Ca^{2+]$, $Mg^{2+}$, $Cl^{-}$, $NO_{3}^{-}$, and $SO_{4}^{2-}$ by both an atomic absorption spectrophotometer and an ion chromatograph. The purpose of this study was t develop a receptor methodology for quantitative assessment of PM-10 sources. The data obtained from this study were ex-tensively examined using the target transformation factor analysis(TTFA) and the chemical mass balance (CMB). When TTFA was initially applied seasonal basis. five sources(such as automobile-related, sulfate-related, incine-ration, soil and combustion-related) were identified both during winter and fall. Since the total number and the type of sources were resolved by TTFA for the four seasons, CMB was employed to cross-check the results of TTEA. The total of six source categories identified by TTEA was intensively investigated on the basis of source profiles acquired from various source libraries established both in Korea and abroad. The results of this study showed the applicability of two popular receptor models as a new methdology for quantitative assessment PM-10 sources in Korea. Seasonally segmented data sets with the combined application of TTFA and CMB yielded a physically reasonable source apportionment result and provided a mean to increase the number of potential sources. Furthermore, this study suggested the possibility of the CMB application to ambi-ent data from Korea after identifying potential sources through traditional factor analysis.

• Asian Journal of Atmospheric Environment
• /
• v.4 no.3
• /
• pp.189-197
• /
• 2010

An orchestrated attempt was made to analyze samples of bulk and individual particulate matters (PM) collected at the Gosan ground-based station on the west coast of Jeju, Korea. A two-stage filter pack sampler was operated to collect particles in both large (> $1.2\;{\mu}m$) and small size fractions (< $1.2\;{\mu}m$) between the Asian dust (hereafter called "AD") storm event and non-Asian dust period. Elemental components in bulk and individual particles were determined by PIXE and synchrotron XRF analysis systems, respectively. To assess the transport pathways of air parcels and to determine the spatial distribution of PM, the backward trajectories of the Meteorological Data Explorer (Center for Global Environmental Research, 2010) and the NOAA's HYSPLIT dispersion-trajectory models were applied. In line with general expectations, Si and other crustal elements in large size particles showed considerably higher mass loading on AD days in comparison with non-AD days. Computation of the crustal enrichment factors [(Z/Si)$_{particle}$/(Z/Si)$_{desert}$ sand] of elements in large size particles (> $1.2\;{\mu}m$) allowed us to estimate the source profile and chemical aging of AD particles as well as to classify the soil-origin elements. On the basis of a single particle analysis, individual AD particles are classified into three distinct groups (neutralized mineral particles, S-rich mineral particles, and imperfectly neutralized particles).

• Journal of Microbiology and Biotechnology
• /
• v.12 no.2
• /
• pp.249-257
• /
• 2002

Pseudomonas fluorescens GL20 is a plant growth-promoting rhizobacterium that produces a large amount of hydroxamate siderophore under iron-limited conditions. The strain GL20 considerably inhibited the spore germination and hyphal growth of a plant pathogenic fungus, Fusarium solani, when iron was limited, significantly suppressed the root-rot disease on beans caused by F. solani, and enhanced the plant growth. The mechanism for the beneficial effect of strain GL20 on the disease suppression was due to the siderophore production, evidenced by mutant strains derived from the strain. Analysis of the outer membrane protein profile revealed that the growth of strain GL20 induced the synthesis of specific iron-regulated outer membrane proteins with molecular masses of 85- and 90 kDa as the high-affinity receptors for the ferric siderophore. In addition, a cross-feeding assay revealed the presence of multiple inducible receptors for heterologous siderophores in the strain. In order to induce increased efficacy and potential in biological control of plant disease, a siderophore-overproducing mutant, GL20-S207, was prepared by NTG mutagenesis. The mutant GL20-S207 produced nearly 2.3 times more siderophore than the parent strain. In pot trials of beans with F. solani, the mutant increased plant growth up to 1.5 times compared with that of the parent strain. These results suggest that the plant growth-promoting P. fluorescens GL20 and the genetically bred P. fluorescens GL20-S207 can play an important role in the biological control of soil-borne plant diseases in the rhizosphere.

• Journal of Microbiology and Biotechnology
• /
• v.12 no.1
• /
• pp.71-76
• /
• 2002

Soil samples were screened for actinomycete strains capable of producing phospholipase D, and a strain, Streptomyces sp. YU100, showing a high transphosphatidylation activity was isolated. This strain secreted phospholipase D in a culture broth after 12 h of cultivation, and its productivity continued to increase for 36 h of fermentation. In addition, its transphosphatidylation rate of phosphatidylcholine to phosphatidylserine was almost $68\%$ within 1 h. The morphological and chemotaxonomical characteristics showed that this strain could be classified as a number of the Streptomycetaceae family, particularly due to the spiral form of its spore chain consisting of 60-70 smooth spores $(0.75{\times}1.0{\mu}m$) on an aerial mycelium, FA-2c type of fatty acid profile in the cell wall, and LL-DAP component in the cell wall peptidoglycan. A phylogenetic analysis of the 16S rDNA provided a clue that the strain YU100 was actually a member of the genus Streptomyces, because the determined sequence exhibited a higher homology with Streptomyes sp. ASB27, S. peucetius JCM9920, and S. griseus ATCC10137. A dendrogram based on the 16S rDNA sequences also showed a phylogenetic relationship between the strain YU100 and these strains. However, the strain YU100 has not yet been assigned to a particular species, because of absence of any other classified species with a high matching score.