• Title/Summary/Keyword: urban characterization

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Durability of high performance sandcretes (HPS) in aggressive environment

  • Benamara, Dalila;Tebbal, Nadia;Rahmouni, Zine El Abidine
    • Advances in concrete construction
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    • v.8 no.3
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    • pp.199-206
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    • 2019
  • High performance sandcretes (HPS) are new concretes characterized by particles having a diameter less than 5 mm, as well as very high mechanical strength and durability. This work consists in finding solutions to make sandcretes with good physico-mechanical and durability properties for this new generation of micro-concrete. However, upgrading ordinary sandcrete into high performance sandcrete (HPS) requires a thorough study of formulation parameters (equivalent water/binder ratio, type of cement and its dosage, kind and amount of super plasticizer, and gravel/sand ratio). This research study concerns the formulation, characterization and durability, in a sulphate environment, of a high performance sandcrete (HPS), made from local materials. The obtained results show that the rheological properties of fresh concrete and mechanical strength differ with the mineralogy, density and grain size distribution of sands and silica fume used.

Thermal Characteristics of Daegu using Land Cover Data and Satellite-derived Surface Temperature Downscaled Based on Machine Learning (기계학습 기반 상세화를 통한 위성 지표면온도와 환경부 토지피복도를 이용한 열환경 분석: 대구광역시를 중심으로)

  • Yoo, Cheolhee;Im, Jungho;Park, Seonyoung;Cho, Dongjin
    • Korean Journal of Remote Sensing
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    • v.33 no.6_2
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    • pp.1101-1118
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    • 2017
  • Temperatures in urban areas are steadily rising due to rapid urbanization and on-going climate change. Since the spatial distribution of heat in a city varies by region, it is crucial to investigate detailed thermal characteristics of urban areas. Recently, many studies have been conducted to identify thermal characteristics of urban areas using satellite data. However,satellite data are not sufficient for precise analysis due to the trade-off of temporal and spatial resolutions.In this study, in order to examine the thermal characteristics of Daegu Metropolitan City during the summers between 2012 and 2016, Moderate Resolution Imaging Spectroradiometer (MODIS) daytime and nighttime land surface temperature (LST) data at 1 km spatial resolution were downscaled to a spatial resolution of 250 m using a machine learning method called random forest. Compared to the original 1 km LST, the downscaled 250 m LST showed a higher correlation between the proportion of impervious areas and mean land surface temperatures in Daegu by the administrative neighborhood unit. Hot spot analysis was then conducted using downscaled daytime and nighttime 250 m LST. The clustered hot spot areas for daytime and nighttime were compared and examined based on the land cover data provided by the Ministry of Environment. The high-value hot spots were relatively more clustered in industrial and commercial areas during the daytime and in residential areas at night. The thermal characterization of urban areas using the method proposed in this study is expected to contribute to the establishment of city and national security policies.

Purification and Characterization of Extracellular Temperature-Stable Serine Protease from Aeromonas hydrophila

  • Cho, Soo-Jin;Park, Jong-Ho;Park, Seong-Joo;Lim, Jong-Soon;Kim, Eung-Ho;Cho, Yeon-Jae;Shin, Kwang-Soo
    • Journal of Microbiology
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    • v.41 no.3
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    • pp.207-211
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    • 2003
  • Extracellular protease, from Aeromonas hydrophila Ni 39, was purified 16.7-fold to electrophoretic homogeneity with an overall yield of 19.9%, through a purification procedure of acetone precipitation, and Q Sepharose and Sephacryl S-200 chromatographies. The isoelectric point of the enzyme was 6.0 and the molecular mass, as determined by Sephacryl S-200 HR chromatography, was found to be about 102 kDa. SDS/PAGE revealed that the enzyme consisted of two subunits, with molecular masses of 65.9 kDa. Under standard assay conditions, the apparent $K_{m}$ value of the enzyme toward casein was 0.32 mg/ml. About 90% of the proteolytic activity remained after heating at 60$^{\circ}C$ for 30 min. The highest rate of azocasein hydrolysis for the enzyme was reached at 60$^{\circ}C$, and the optimum pH of the enzyme was 9.0. The enzyme was inhibited by the serine protease inhibitor, phenylmethylsulfonyl fluoride (PMSF), by about 87.9%, but not by E64, EDTA, pepstatin or 1,10-phenanthroline. The enzyme activity was inhibited slightly by Ca$\^$2+/, Mg$\^$2+/ and Zn/supb 2+/ ions.

Characterization of bromine and chlorine in the closed combustion system (연소 반응기를 이용한 브롬 및 염소의 함량 측정에 관한 연구)

  • Choi, Ki-In;Kwon, Duck-Jun;Bae, Sung-Jin;Lee, Dong-Hoon
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.21 no.6
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    • pp.274-279
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    • 2011
  • In this study, we investigated the analytical methods for bromine (Br) and chloride (Cl) with oxygen combustion bomb, using a halogen-containing polymer materials. On measuring Cl content, it showed less reproducibility of the results applying Mohr method or potentiometric titration method than those applying acid-base titration method. In both Br and Cl tests with an oxygen combustion bomb, their concentrations in the absorption and cleaning solution with distilled water were much higher than those in the combustion gas. On the other hand, the concentration level of Br measured by the oxygen combustion bomb method were a little bit lower than those measured by XRF or combustionion chromatography.

Characterization of Atmospheric Concentrations of Volatile Organic Compounds in Industrial Areas of Pohang and Gumi Cities (포항과 구미의 대규모 산단지역 대기 중 휘발성 유기화합물 농도 분포 특성에 관한 연구)

  • Baek Sung-Ok;Kim Soo-Hyun;Kim Mi-Hyun
    • Environmental Analysis Health and Toxicology
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    • v.20 no.2 s.49
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    • pp.167-178
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    • 2005
  • This study was carried out to evaluate the temporal, spatial, and seasonal variations of VOC, and to characterize the VOC concentrations in two large industrial complexes located in Pohang and Gumi cities. Twenty -four hours continuous sampling of selected VOC was made with STS 25 sequential tube samplers and double-bed adsorbent tubes. Air samples were collected every three hour interval for 7 consecutive days in each site during summer and winter. VOC were determined by thermal desorption coupled with GC/MS. A total of 27 VOCs of environmental concern were determined, including aliphatic, aromatic and halides. Generally. concentrations of toxic VOC were higher in Gumi than Pohang, and VOC levels in industrial areas were typically several-fold higher than those in residential areas. The most abundant VOC appeared to be toluene for both cities. However, chlorinated VOC were higher in Gumi than Pohang, while aromatic VOC were more abundant in Pohang than in Gumi. Two cities showed relatively different variations of VOC concentrations within a day. It is likely that traffic related sources are major factors affecting the VOC in Pohang, and industrial solvents usages are important sources in Gumi. These results imply that the occurrence and levels of atmospheric VOC are strongly dependent on the type of industries in each city. Therefore, in order to develop any control strategies or to establish the priority rankings for VOC in large industrial complexes, the type of industries and the occurrence of VOC in the atmosphere should be taken into consideration.

A Study on the Demand of Development in the Villages of Rural Areas - Focused on the Analysis of Preliminary Plans about Rural Community Development Project - (농촌지역 마을의 개발수요에 관한 연구 -농촌마을종합개발사업 예비계획서 분석을 통해-)

  • Cho, won-seok;Yoo, Young-Mo
    • Journal of the Korean Institute of Rural Architecture
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    • v.13 no.3
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    • pp.21-28
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    • 2011
  • This paper was able to indicate to the results the following thing that attempted a required potential development demand, through the contents and cost analysis in Rural Community Development Project. Nowadays, Rural Areas comparatively have a lot of development demands related to improvements environmental of residence life and construction of Urban-Rural Exchange Facility, on the other and, there is comparatively a few facilities demands regarding agriculture production. Demand is cold storage facilities and agricultural products direct sale facilities expansion to be able to raise value added of agricultural products as facilities related comparatively a little agriculture production, and an improvement of residence life comparatively has a lot of repair environmental uninhabited house repair, river-front and the roadside, rest shelter creation demands. However, that should be forecasted so that aging of rural, population decrease and development demand is caused by a lot of issues such as maintenances operation of many Urban-Rural Exchange Facilities and a similar program and content has a lot of them in bilateral adjacent zones. Therefore, in the future plan shall attempt efficiency operating facilities and a program through characterization and network of zone so that facilities and program can have complementary relation in the adjacent zones. And item development and an investor are necessary regarding new labor force supply for continuous value maintenance of space and returning to the farm that there were the reverse agriculture production and Amenity which are an rural village. Furthermore, developmental plan of rural village is necessary through the demand analyses that a citizen wishing for things.

A Study on the Port Space Typification and Characterization Based on FBCs (Form Based Codes를 기반으로 한 항만공간 유형화 및 특성분석)

  • Hwang, Sun Ah;Kim, Jong Gu
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.37 no.1
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    • pp.255-268
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    • 2017
  • A lot of city have different characteristics in their location, space and environment each other. These characters are the factors showing inherent placeness of each space, and those factors should be reflected sufficiently in urban planning and development. Nonetheless, there are many parts that are not actually reflected in the plan, and this creates a space of unexpected arming. Especially, port area in a port city has strong characteristics of culture, history, geography and environment of the city concerned so it must make more creative and unique space. Therefore, it is considered that not only the physical factors but also the social factors should be actively reflected to highlight the place character of the port space. In this paper we are to construct the factors forming the placeness of port space based on the Form Based Codes rising as a flexible urban planning method in order to avoid rigidity of existing use district zoning system, and establish the placeness character of each port area.

Backward estimation of precipitation from high spatial resolution SAR Sentinel-1 soil moisture: a case study for central South Korea

  • Nguyen, Hoang Hai;Han, Byungjoo;Oh, Yeontaek;Jung, Woosung;Shin, Daeyun
    • Proceedings of the Korea Water Resources Association Conference
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    • 2022.05a
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    • pp.329-329
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    • 2022
  • Accurate characterization of terrestrial precipitation variation from high spatial resolution satellite sensors is beneficial for urban hydrology and microscale agriculture modeling, as well as natural disasters (e.g., urban flooding) early warning. However, the widely-used top-down approach for precipitation retrieval from microwave satellites is limited in several hydrological and agricultural applications due to their coarse spatial resolution. In this research, we aim to apply a novel bottom-up method, the parameterized SM2RAIN, where precipitation can be estimated from soil moisture signals based on an inversion of water balance model, to generate high spatial resolution terrestrial precipitation estimates at 0.01º grid (roughly 1-km) from the C-band SAR Sentinel-1. This product was then tested against a common reanalysis-based precipitation data and a domestic rain gauge network from the Korean Meteorological Administration (KMA) over central South Korea, since a clear difference between climatic types (coasts and mainlands) and land covers (croplands and mixed forests) was reported in this area. The results showed that seasonal precipitation variability strongly affected the SM2RAIN performances, and the product derived from separated parameters (rainy and non-rainy seasons) outperformed that estimated considering the entire year. In addition, the product retrieved over the mainland mixed forest region showed slightly superior performance compared to that over the coastal cropland region, suggesting that the 6-day time resolution of S1 data is suitable for capturing the stable precipitation pattern in mainland mixed forests rather than the highly variable precipitation pattern in coastal croplands. Future studies suggest comparing this product to the traditional top-down products, as well as evaluating their integration for enhancing high spatial resolution precipitation over entire South Korea.

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Development of Integrated Management System Based on GIS on Soft Ground (GIS 기법을 이용한 연약 지반 시공 관리 시스템의 개발)

  • Chun, Sung-Ho;Woo, Sang-Inn;Chung, Choong-Ki;Choi, In-Gul
    • Journal of the Korean Geotechnical Society
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    • v.23 no.7
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    • pp.37-46
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    • 2007
  • In the practice of preloading method for soft ground improvement, field engineers need information of ground properties, construction works and field monitoring on ground behaviors of the site. So, integrating all these informations into one database can provide more efficient way for managing and utilizing the data for construction management. In this study, integrated system for construction management of ground improvement sites under preloading is developed. The developed system consists of database (DB) and application program. The database contains all collected data in a construction site and processed data in the system with their geographic information. All informations in the database are standardized from the result of data characterization. Application program performs various functions on managing and utilizing information in the database; pre- and post- data processing with graphic visualization of output, spatial data interpolation, and prediction of ground behavior using field measuring data. And by providing integrating informations and predictions over entire project area with comprehensible visual displays, the applicability and effectiveness of the developed system for construction management were confirmed.