• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.292-299
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• 2022

This study was conducted to analyze physical and chemical properties of horticultural substrates and response of hydroponically grown two cultivars of 'Namcheon' and 'Somirang' perilla by four different substrates: coir (chip:dust = 5:5), perlite, granular rockwool, and commercial mixed substrate (cocopeat:peatmoss:vermiculite:perlite: zeolite = 50:25:10:10:5). There were no significant differences in EC and pH according to substrates. Container capacity was the greatest in granular rockwool, and it showed appropriate levels in mixed substrate and coir. Air space was higher in coir and perlite than the other treatments. Bulky density reached a proper standard in all substrates excepting coir. The leaf length and width of 'Namcheon' indicated the most in mixed substrate, though the value of 'Somirang'was greatest in coir substrate. The leaf weight of both cultivars was highest in mixed substrate, and relatively low in coir and perlite. The total yield of leaves was separated by two groups: higher group, which are mixed substrate and granular rockwool, and lower group, which are coir and perlite. There was a large gap by 28% between these two groups. Therefore, this study suggests that substrates with high water holding capacity such as mixed substrate or granular rockwool are most suitable for the hydroponic cultivation of perilla, which require sufficient moisture supply to the root zone.

• Korean Journal of Heritage: History & Science
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• v.45 no.1
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• pp.86-101
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• 2012

The constituting rocks of Multi-storied Round shape stone Pagoda of Unjusa Temple are lithic tuff and rhyolite tuff breaccia which show green or grey and also rock fragment with poor roundness are present in the structure. lithic tuff is composed of feldspar and quartz which are glassy texture and cryptocrystalline and also micro crystalline are scattered. phenocryst quartz and feldspar in the substrate composed of feldspar and opaque minerals are found in rhyolite tuff breaccia. dust, exfoliation, cavity, fracture and crack are observed in all the stone of the pagoda and the result of Infrared Thermography shows partial inter cavities have developed severely which may cause further exfoliation. In addition, a great deal of various grey, green, and yellow brown lichen as well as bryophyte are present at the upper part of eastern and western roof stone located above the third floor. Discolors remarkably shown at stereobate and roof stone are identified as inorganic pollutants such as manganese oxide, iron oxide and iron hydroxide. The stone of the pagoda of the Chemical Index of Alteration (CIA) and the Weathering Potential Index (WPI) are 55.69 and 1.12 respectively and this corresponds to a highly weathered stage. The measured values, average ultrasonic velocity 2,892m/s, coefficient of weathering 0.4k and compressive strength $1,096kg/cm^3$, suggest that the rock strength and durability are weakened.

• Journal of Conservation Science
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• v.25 no.2
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• pp.179-196
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• 2009

The Gaetaesajiseokbulibsang (Treasure No. 219) consists of light gray and coarse to medium-grained granodiorite with feldspar phenocrysts in part. Magnetic susceptibility of the rock material was measured as 12.06(${\times}10^{-3}$ SI unit), being different from the granite($0.19{\times}10^{-3}$ SI unit) in the Mt. Cheonho. This indicates the raw material has been supplied from the outside. As a result of deterioration assessment, exfoliation of the Right Buddha, cement and dust of the Main Buddha were estimated as 35.2%, 21.1% and 25.0%. The ultrasonic velocity was measured as 2850.2m/s(Main Buddha), 2648.4m/s(Left Buddha) and 2644.5m/s(Right Buddha). The compressive strength calculated from the velocity showed low in the Right Buddha among three and the all pedestal parts which corresponds to the result of deterioration assessment. The indoor mean temperature and relative humidity of the shelter were $13.7^{\circ}C$ and 79.0%. It is evaluated that the indoor microclimate was stable and the shelter functioned to reduce climatic fluctuation of the outdoor. However, water condensation was occurred on the surface of the pedestal part during spring and summer, and freezing in winter season might also be done. These factors were probable to be a main cause of the surface exfoliation of the Triad Buddha Statues. Therefore, dehumidification and heating system in the shelter should be applied to prevent further deterioration.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.6
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• pp.589-604
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• 2021

Waterjets for rocks have various advantages of the non-contact and eco-friendly excavation using only water and abrasive. To overcome the problems (e.g., dust and noise occurrence) of the conventional drilling methods, waterjet excavation methods are broadly used. It is advantageous to operate a couple of nozzles in order to increase the waterjet excavation efficiency. When multiple nozzles are used, it is essential to analyze the excavation performance and shape according to the nozzle operation method. In this study, nozzle angle, horizontal distance between nozzles, and standoff distance were defined as nozzle operating parameters and the excavation performance and shape were analyzed. As a result of the experiment, when the nozzle angle and standoff distance are increased, the excavation depth is decreased and the effective depth tends to be increased. In addition, based on the experimental results, the excavation shape criteria required for nozzle insertion were proposed and optimal nozzle operating parameters were derived according to the criteria. This study result is expected to be used as useful basic research in the future development of multiple waterjet nozzles for rock drilling.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.1
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• pp.42-50
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• 2009

Samples of subway dust were collected by the air filter system of 30 subway stations on Daegu subway line 1 in January 2008. Samples were sieved below 100 ${\mu}m$, and 14 elements were analyzed using ICP after acid extraction. Results obtained from the source assessment of trace elements using enrichment factor showed that Ca, Fe, K, Mg, Mn, Na, V were influenced by natural sources such as weathered rock and resuspended soil, while Cd, Cr, Cu, Ni, Pb and Zn were influenced by anthropogenic sources such as fuel combustion and waste incineration. Concentrations were remarkably higher in components from natural sources than in components from anthropogenic sources. Anthropogenic sources were significantly affected by indoor dusts than outdoor dusts. Results of pollution indices of heavy metals indicated that indoor dusts were more contaminated with heavy metal ions than outdoor dusts. The correlation analysis among trace elements indicated that components were much correlated in the order of natural sources-anthropogenic sources, anthropogenic sources-anthropogenic sources, natural sources-natural sources in both indoor and outdoor dusts. Trace element components of outdoor dusts were largely correlated than those of indoor dusts. In addition, indoor dusts were significantly affected by outdoor dusts rather than depth from the surface or the average daily number of subway passengers.

• Journal of Korean Society of Forest Science
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• v.101 no.3
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• pp.387-394
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• 2012

The study was conducted to develop an effective forest resources use models for an alternate use of abandoned quarry by an attitude survey. According to the result of survey, a pessimistic view due to dust, noise pollution, and forest damage was 5% higher than an affirmative view by economic benefits from the development of quarry. The 42% of the respondents preferred the alternate use of abandoned quarry and the 25% of the respondents wanted an art and cultural space. The optimum size of alternate use was 5-10 ha (43%) with the requirement of nearby residents (32%). According to the SWOT analysis for abandoned quarry, the strength factors were an effective use of land, the content development of modern industrial inheritance + cultural and art fusion, attraction for nearby city and visitors, a harmony of beauty landscape and clean environment, and a sustainable increase of domestic and foreign visitors with the 5-day-work week. The opportunity factors were the improvement of traffic networks through KTX and local highway, the creation of the new growth engines with the establishment of artistic creation belts, the providing of unique cultural and art space through grafting of tour and education, the creation of local income through stone processed goods, and the vitalization of local development through eco-city. The weakness factors were a psychological remoteness and backwardness, and the weakness of staying tour infra. The threat factors were a poor financial support for sustainable development in nearby quarry and a modify of legal and institutional system for the alternated use of abandoned quarry. The developed restoration models for the alternate use in abandoned quarry are classified to a sculpture park, a waterfall and lake park, a rock-climbing, a sports park + forest park, a native botanical garden, a culture and art park, a complex park, a water storage site, a water storage site to extinguish forest fire, a geriatric hospital, an agricultural facility, and a school site types etc. The results suggest that the alternate use in the abandoned soil and stone quarry is needed to establish facility use models with consideration of user's preference.