• Journal of the Korean Geographical Society
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• v.39 no.4
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• pp.495-513
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• 2004

The shape of land surface work as a cradle for various environmental processes and human activities. As spatially distributed process modelings become increasing important in current research communities, a classification system that delineates land surface into characteristic geomorphological units is a pre-requisite for sustainable land use planning and management. Existing classification systems are either morphometric or generic, which have limitations to characterize continuous ecological processes over the landscape. A new classification system was developed to delineate the land surface into different geomorphological units from Digital Elevation Models(DEMs). This model assumes that there are pedo-geomorphological units in which distinct sets of hydrological, pedological, and consequent ecological processes occur. The classification system first divides the whole landsurface into eight soil-landscape units. Possible energy and material nows over the land surface were interpreted using a continuity equation of mass flow along the hillslope, and subsequently implemented in terrain analysis procedures. The developed models were tested at a 12$\textrm{km}^2$ area in Yangpyeong-gun, Kyeongi-do, Korea. The method proposed effectively delineates land surface into distinct pedo-geomorphological units, which identify the geomorphological characteristics over a large area at a low cost. The delineated landscape units mal provide a basic information for natural resource survey and environmental modeling practices.

• Journal of the Korea Concrete Institute
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• v.26 no.3
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• pp.277-285
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• 2014

The purpose of this study is to investigate experimentally the variation factors range having influence on the rheological properties of the combined self-compacting concrete according to materials quality, weighting error and site conditions. Two types cement (blast-furnace slag cement and belite cement), lime stone powder as binder and the optimum mix proportions in the preceded study are selected for this study. Also, variations for sensitivity test are as followings; (1) Concrete temperature 3 cases (2) Surface moisture of sand 5cases (3) Fineness modulus of sand 5cases (4) Specific surface of lime stone powder 3cases (5) Dosage of chemical admixture 5cases. Slump flow ($650{\pm}50mm$), 500 mm reaching time (($7{\pm}3sec$), V-type flowing time ($15{\pm}5sec$) and U-box height (min. 300 mm) are tested for sensitivity. As test results, the variations range for quality control are as followings. (1) Concrete temperature; $10{\sim}20^{\circ}C$(below $30^{\circ}C$) (2) Surface moisture of sand; $base{\pm}0.6%$ (3) Fineness modulus of sand; $2.6{\pm}0.2$ (4) Dosage of chemical admixture; $base{\pm}0.2%$ (5) Specific surface of lime stone powder $6000cm^2/g$. Compared with two types cement including based belite cement (binary type) and based slag cement (ternary type), the combined self-compacting concrete used belite cement type is most stable in the quality control because of high contents for lime stone powder and $C_2S$. It is to propose a control scheme of the combined self-compacting concrete in the actual construction work.

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.1056-1063
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• 2012

Recent rapidly growth in nanotechnolgies is promised novel benefits through the exploitation of their unique industrial and biomedical applications. With increasing utilization of nanomaterials in consumer products, the potential release of nanomaterials into the environment and their impacts on the ecosystem and human health have been the issues of concern. Nanomaterials that was exposed unintentionally in environment might be accumulated in various environmental media, and finally it will be influenced to human and ecosystems. Therefore, it is important to understand the fate and behavior of nanoparticles for understanding effects on environmental media (air, water, and soil phase). Therefore, in this work, we investigated the several cases for environmental exposure of nanomaterials and suggested the direction of further research. In workplace, exposure to air media is dominant, but finally waste and wastewater was moved to the water and soil phase. In addition, we found the existing sewage treatment plant was not suitable to remove completely nanomaterials in wastewater flow. To deeper study, environmental monitoring tool must be developed additionally and we suggested the several analyzing method for aged and pristine physicochemical properties of nanomaterials exposed into environmental media. This review for nanomaterials' exposure to environmental media will be helpful to investigate the environmental fate of nanomaterials and define the suitable treatment method for nano-waste.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.12
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• pp.209-218
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• 2012

Recently, the Field Programmable Stateful Logic Array (FPSLA) was proposed as one of the most promising system integration technologies which will extend the life of the Moore's law. This work is the first proposal of the FPSLA design automation flow, and the approaches to logic synthesis, synchronization, physical mapping, and automatic placement of the FPSLA designs. The synchronization at each gate for pipelining determines the x-coordinates of cells, and reduces the placement to 1-dimensional problems. The objective function and its gradients for the non-linear optimization of the net length and placement density have been remodeled for the reduced global placement problem. Also, a recursive algorithm has been proposed to legalize the placement by relaxing the density overflow of bipartite bin groups in a top-down hierarchical fashion. The proposed model and algorithm are implemented, and validated by applying them to the ACM/SIGDA benchmark designs. The output state of a gate in an FPSLA needs to be duplicated so that each fanout gate can be connected to a dedicated copy. This property has been taken into account by merging the duplicated nets into a hyperedge, and then, splitting the hyperedge into edges as the optimization progresses. This yields additional 18.4% of the cell count reduction in the most dense logic stage. The practicality of the FPSLA can be further enhanced primarily by incorporating into the logic synthesis the constraint to avoid the concentrated fains of gates on some logic stages. In addition, an efficient algorithm needs to be devised for the routing problem which is based on a complicated graph. The graph models the nanowire crossbar which is trimmed to be embedded into the FPSLA fabric, and therefore, asymmetric. These CAD tools can be used to evaluate the fabric efficiency during the architecture enhancement as well as automate the design.

• The Journal of Sustainable Design and Educational Environment Research
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• v.16 no.3
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• pp.69-76
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• 2017

Indoor Air Quality(IAQ) affects physical and mental state of person who is residing indoor. Also, it manages daily life condition of Indoor Air in the building. According to the study, office workers spend 23 hours and 12 minutes, about 97% of his/her day indoor. Therefore, Indoor air quality affects not only the health of the person whose staying inside for a long hours but also the productivity and efficiency of work. This study conduct investigations on employees' awareness of indoor air quality of office in university. By doing so, we are able to determine current situation and provide basic data of improvement for derived problems. As a result, most of the respondents were not satisfied with ventilation and moisture which are elements of Indoor Air Quality. These led people to struggle with symptoms of health. Therefore, to improve the indoor air quality of a university office, it is necessary to exchange the air six times an hour according to recommendation of Refrigeration and Air Conditioning Engineers (ASHRAE)in the United States. Also, plan for Ventilation system that consider temperature, humidity and air flow indoor shall be provided for high quality conformability. furthermore, It is necessary to consider the multilateral in factors of generation of revenue through health care savings of workers and improvement of productivity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.1
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• pp.73-78
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• 2012

Excessive intake of trans fats is known to be a risk factor for cardiovascular diseases. Previously, we have shown that green tea extract (GTE) lowers the intestinal absorption of lipids and lipid-soluble compounds in rats. This study was conducted to investigate a possible role of GTE on the lymphatic absorption of elaidic acid, a major trans fat in the diet. Adult male Sprague-Dawley rats with lymph duct cannula were infused via an intraduodenal catheter at 3.0 mL/hr for 8 hr with a lipid emulsion containing $180.0{\mu}mol$ elaidic acid, $400.0{\mu}mol$ triolein, $20.7{\mu}mol$ cholesterol, $3.1{\mu}mol$ ${\alpha}$-tocopherol, and $396.0{\mu}mol$ sodium-taurocholate with or without (control) GTE in a 24 mL PBS buffer (pH, 6.4). Simultaneously, lymph was collected hourly for 8 hr via the lymph duct cannula. There was a significant difference in lymph flow by GTE. Also, the lymphatic absorption of elaidic acid for 8 hr was significantly lower in rats infused with GTE than in those not infused with GTE. Similarly, GTE infusion decreased the lymphatic outputs of cholesterol, oleic acid, and phospholipids, compared with the controls. These findings provide clear evidence that GTE has an inhibitory effect on the intestinal absorption of elaidic acid and other lipids. Our work here provides the foundation for further studies to examine and evaluate dietary strategies to ameliorate dietary trans fats from the diet.

• Journal of Bio-Environment Control
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• v.23 no.4
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• pp.356-363
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• 2014

This work was conducted to investigate the field growth and yield of the sweetpotato (Ipomoea batatas) slips grown under different light emitting diodes (LEDs). Sweet potato cuttings of 3 cultivars ('Matnami', 'Shinhwangmi', and 'Yeonhwangmi') were cultivated under fluorescent lamp (FL) and several LEDs (PPF $150{\pm}5{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ at 20cm distance) in deep flow culture system for 20 days. The plants were acclimatized under sunlight for 10 days, and then cuttings (30cm length) were planted with $75{\times}25cm$ planting density on June 10th, covered with black vinyl film during growth period. Length and diameter of vine, number of root were excellent in the red plus blue (7:3) LED than the other treatments. At 30 days after planting, the survival rate in red plus blue (7:3) LED was significantly higher than that in FL and red LED, and it was not different among cultivars. Vine length, vine diameter, and number of node were not significant among LED light qualities and cultivars. After 120 days in the field cultivation, vine length, vine diameter, number of node, number of branch, and fresh weight of shoot were not significant among LED light qualities, but those except the number of branch showed significant differences among cultivars. Yield characteristics among LED light colors were not significant, but weight of storage root per plant, mean weight of storage root, and yield showed significant differences among cultivars. The yield per 10a in 'Matnami', and 'Yeonhwangmi' was significantly higher than that in 'Shinhwangmi'.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.8
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• pp.1051-1057
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• 2010

This paper proposes a method that involves a combination of FDM and FEM for analyzing casting process. At present, many numerical analysis methods such as FDM, FEM, and BEM are used for solving engineering problems. For a given problem, a specific method that is suited to the problem is adopted; in general, FDM or FVM is favored for problems related to fluid flow or heat transfer, and FEM is adopted in stress analysis. However, there is an increasing need for using a combined method for complex and coupled phenomena analysis. Hence, we proposed a method in which FDM and FEM are coupled in three-dimensional space, and we applied this method to analyze casting process. In the proposed method, solidification and heat transfer was analyzed by using FDM. The field data such as temperature distribution were converted into a format suitable for FEM analysis that was used for calculating thermal stress distribution. Using the proposed method, we efficiently analyzed the analysis process from the viewpoints of work and time.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.5
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• pp.375-380
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• 2017

This paper reports the results of an acceleration test to predict the contact-induced failure that could occur at the cylinder-to-hole joint for the fuel rod of a sodium-cooled fast reactor (SFR). To incorporate the fuel life of the SFR currently under development at KAERI (around 35,000 h), the acceleration test method of reliability engineering was adopted in this work. A finite element method was used to evaluate the flow-induced vibration frequency and amplitude for the test parameter values. Five specimens were tested. The failure criterion during the life of the SFR fuel was applied. The S-N curve of the HT-9, the material of concern, was used to obtain the acceleration factor. As a result, a test time of 16.5 h was obtained for each specimen. It was concluded that the $B_{0.004}$ life would be guaranteed for the SFR fuel rods with 99％ confidence if no failure was observed at any of the contact surfaces of the five specimens.

• Clean Technology
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• v.13 no.4
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• pp.266-273
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• 2007

The adsorption properties of the activated carbon-based adsorbents were studied to remove COS emitted from $SO_2$ catalytic reduction process on the integrated gasification combined cycle (IGCC) system in this work. Transition metal supported catalysts and mixed metal oxide catalysts were used for the $SO_2$ catalytic reduction. The mechanism of COS produced from the $SO_2$ reduction and the COS concentration s according to the reaction temperature were investigated. In this study, an activated carbon and a modified activated carbon doped with KOH were used to remove the very low concentration of COS effectively. The adsorption rate and the breakthrough time of COS were measured by a thermo gravity analyzer (TGA, Cahn Balance) and a fixed bed flow reactor equipped with GC-pulsed flammable photometric detector (PFPD), respectively. It was confirmed that the COS breakthrough time of the activated carbon doped with KOH was longer than that of an activated carbon. In conclusion, the modified-activated carbon having a high surface area showed a high adsorption rate of COS produced from the $SO_2$ reduction.