• Journal of The Korean Association For Science Education
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• v.34 no.2
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• pp.123-134
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• 2014

This study aims to develop and validate an instrument to measure students' attitude toward convergence. To do so, we have defined five constructs (i.e. knowledge about convergence, personal relevance, social relevance, interest and self-efficacy) of 'attitude toward convergence' based on literature review, developed items, and collected data from 233 11th grade science track students. The validity of these items have been evaluated by Messick's framework (1995) (i.e. content, substantive, structural aspects of validity), experts' review, Rasch analysis, and confirmatory factor analysis using structural equation modeling. Our results have confirmed the five constructs and 23 selected items have met the benchmark of item validity. Moreover, the theoretical model illustrating that the high level of attitude toward convergence increases the level of science motivation has also been supported by the data. The items developed in this study will be used to measure students' attitude toward convergence and to estimate the effect of learning program for convergence science.

• Journal of the Korean Institute of Landscape Architecture
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• v.48 no.3
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• pp.1-11
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• 2020

Urban parks are important spaces of ecological and socio-cultural value to citizens who lead busy lives in increasingly complex and densely populated megalopolises. However, creating and maintaining city parks takes the will of the authorities to put it into practice and provide the attendant financial resources. That explains why we are focused on the budget aspects for the Seoul Metropolitan City in relation to creating park spaces. Our findings were as follows: 1) The overall city budget has steadily increased, but the budget allocated to Green Seoul Bureau and new park development has decreased since 2011. 2) As for elected officials, the budget grew during the time of the first, third, and fourth mayors as the creation of parks was considered to be a major priority, but after the sixth popularly elected mayor, the budget was sharply cut. 3) About 10% of the budget was allocated to the parks managed by the self-governing districts, compared to the ones under the direct management of the city. Furthermore, the analysis of the average annual budget for each park and how long (in terms of year) the budget for each park is invested showed that it was classified into three different types of category. Local governments adhere to the principle that their budget must be compiled and expended for a single year, which makes it hard to establish and push ahead with a long-term plan. However, as parks and green areas should not be approached from a short-term perspective for performance but from a long-term perspective, securing the consistent amount of budget is essential. This study has significance in that it attempted to analyze the budget issues related to parks, which has not been studied in depth so far, but the subject in this paper was limited to the budget for Green Seoul Bureau. Therefore, further research is needed because the parks managed by the self-governing districts were not considered.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.11
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• pp.1716-1723
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• 2014

This study was designed to examine the change in physical properties of extruded brown rice-vegetable mix at different pregelatinized brown rice contents and $CO_2$ gas injection. Moisture content, screw speed and die temperature were fixed to 30%, 100 rpm and 60, respectively. $CO_2$ gas injection was adjusted to 0, 300, 600, and 800 mL/min. The content of vegetables (carrot, pumpkin, kale and Angelica keiskei) mix was fixed 5%. Pregelatinized and raw brown rice powder were blended as the ratio of 0/95, 30/65 and 50/45. Specific mechanical energy input decreased as pregelatinized brown rice ratio increased. Expansion index increased and the size and number of pores increased but density decreased with the increasing in $CO_2$ gas injection. Gelatinization degree increased as $CO_2$ gas injection increased. In conclusion, cold extrusion with $CO_2$ gas injection at $60^{\circ}C$ die temperature could be applied for Saengsik (uncooked food) making.

• Journal of Environmental Impact Assessment
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• v.24 no.1
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• pp.1-15
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• 2015

To mitigate the impacts of climate change on agricultural ecosystems, development of agricultural management for enhanced soil carbon sequestration is required. In this study, the effects of fertilizer types (chemical fertilizer and manure compost), cropping systems, and crop residue management on SOC(Soil Organic Carbon) sequestration were investigated. Summer corn and winter barley were cultivated on experimental plots under natural rainfall conditions for two years with chemical fertilizer and manure compost. Soil samples were collected conducted and analyzed for SOC for soil. To estimate long-term variation patterns of SOC, DNDC was run with the experimental data and the weather input parameters from 1981 to 2010. DNDC simulation demonstrated SOC reduction by chemical fertilizer treatment unless plant residues are returned; whereas compost treatments increased SOC under the same conditions and SOC increment was proportional to compost application rate. In addition, SOC further increased under corn-barley cropping system over single corn cropping due to more compost application. Regardless of nutrient input type, residue return increased SOC; however, the magnitude of SOC increase by residue return was lower than by compost application.

• Journal of the Korea Organic Resources Recycling Association
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• v.24 no.2
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• pp.67-74
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• 2016

This study was purposed to evaluate the characteristic changes of the solidified livestock manure fuel(SLMF) through the application of compression treatment process. The compression process led to an increase of VS/TS ratio (Volatile solids/Total solids ratio) and moisture removal effect of SLMF. The amount of leachate withdrawn from dairy cattle manure and Hanwoo manure by compression were 21~26%(w/w) and 15~20%(w/w), respectively. The specific gravity of the leachate of dairy cattle manure and Hanwoo manure were 1.01 and 0.99, respectively. The dehydrated cow manure was easily processed into ball-shaped solidified fuel. The drying time of the SLMF was proportional to the diameter of the solidified fuel. The highest heating value was observed in diameter range of 10~15mm SLMF. It is concluded that the higher heating value of 10~15mm SLMF was related with the amount of fibrous matter contained in the SLMF.

• Journal of the Korea Organic Resources Recycling Association
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• v.24 no.4
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• pp.105-112
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• 2016

The drying test was carried on the globular type cow manure pellet for use in solid fuel applications. The globular type cow manure pellet fuel was sorted according to size by rotatory sieves. The three kind of drying methods such as convection hot-air drying method, infrared ray drying method and superheated steam method were used to dry the globular type cow manure pellet. Among the three kind of drying methods, superheated steam method of dry time was the shortest. The apparent specific gravity and low calorific value of dried cow manure pelltes was about $250{\sim}350kg/m^3$ and above 3,000 kcal/kg respectively. The smaller the particle size of cow manure pellets, the less drying time was required. The time was required very less for drying smaller particle size cow manure pellet when compared to larger size. In the case of the same drying condition, it has been found that reducing the particle size of cow manure fuel pellet is an important factor for shortening the drying time of the livestock manure pellet.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.3
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• pp.37-44
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• 2020

The Project supporting organic fertilizer started in 1999 as a national policy. In farmhouse, over application of mixed organic compound fertilizer(OC) caused salt accumulation in plastic film house soil. To replace inorganic fertilizer with OC fertilizer, this study was investigated the effect of OC application on yield and soil chemical properties for lettuce cultivation in plastic film house. The OC fertilizer was applied at 50(OC50+N50), 100(OC100), and 150(OC150) % level of the basal amount of nitrogen fertilizer in soil testing recommendation. And these were compared to NPK(nitrogen, phosphat, and potash fertilizer) and PK treatment. The yield of lettuce in OC100 was similar to that of NPK treatment. In OC 50, 100 and 150 treatments, pH had a tendency to increase than that of NPK treatment. Nitrate nitrogen(NO₃-N) and electrical conductivity(EC) were similar to NPK treatment. These showed that nutrients from OC fertilizer were less likely to accumulate in soil than NPK. Also, use efficiency of nitrogen in OC100 treatment were similar to NPK treatment. These results suggest that OC application as the basal dressing at the 100% level could be best to prevent a nutrient accumulation of soil and to increase the yield and commercial quality for lettuce.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.417-422
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• 2017

One of the most frightening aspects of weapons of mass destruction (WMD) is their ability to cause death in very small quantities without being visible to the public. The military authorities are making considerable effort to ensure the survivability of the combatants in the event of NBC(Nuclear, Biological and Chemical) contamination. Therefore, in this study, modules were developed for the measurement of the positive pressure and for the detection of the chemicals used for the control of the various shut-off valves used in an NBC shelter. In addition, a high performance gas tight shut-off valve was developed that can overcome the disadvantages associated with manual manufacturing, such as the occurrence of defective products and high manufacturing cost. By applying the positive pressure measurement and chemical detection modules, this valve was able to be used to control the facility. The developed gas-tight shut-off valve maintained airtight characteristics at a pressure loss of 28[Pa] at the prescribed wind velocity and an internal pressure of 30[kPa]. It is expected to be possible to control the gas-tight shut-off valve through the remote measurement of the positive pressure, thereby ensuring the foreign independence of import substitution and defense related technology in the future. In addition, by installing these valves in all of the intake ports or exhaust ports connected to the outside of the NBC shelter, it is possible to prevent the damage resulting from the rapid inflow of the storm pressure caused by conventional weapons and nuclear explosions, thereby protecting the people and equipment in the shelter.

• Clean Technology
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• v.23 no.2
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• pp.133-139
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• 2017

Bio-based plastics containing the biomass content higher than 25 wt% have been considered as environment-friendly materials due to their effects on the reduction in the $CO_2$ emission and petroleum consumption as well as biodegradability after use. In this study, poly vinyl chloride, plant-derived plasticizers, by adding a biodegradable catalyst was observed a change in the biodegradability and physical properties. To produce the oxidative decomposition transparent bio film, which is broken down in the initial percent elongation and physical properties such as tensile strength, it was to test the safety of the product as a food packaging material. Poly vinyl chloride, primary plasticizer, secondary plasticizer, anti fogging agent, the combined stabilizer were mixed in a high speed mixer, then extruded using an extrusion molding machine, after cooling, winding, to produce a oxidative decomposition transparent bio film and the control film, with a thickness of $12{\mu}m$ through winder role. Mechanical properties tensile strength, elongation, and the maximum load elongation and biodegradation test. Transparent bio film produced by biodegradation catalyst is compared with the control film. Tensile strength and elongation of films were found to be no significant difference. Further, as a result of the biodegradation test for 45 days based on the ASTM D6954-04 method, biodegrability of film is 61.4%.

• Korean Journal of Food Science and Technology
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• v.25 no.3
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• pp.243-246
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• 1993

For extending the shelf-life of Yukwa (oil puffed rice cake) which is one of the most favorable Korean traditional rice snack, the Yukwa was packed in $O_2$ preventive container and substituted the air with $N_2$ gas or packed with $O_2$ absorbent (ageless sachet). The quality of Yukwa stored at $35^{\circ}C$ was evaluated by POV, AV and TBA including sensory evaluation. The POV of oil in Yukwa of $N_2$ substitute pack and absorbent sachet included were 5.3 and 11.9 meq/kg, respectively, while no packing (control) was 195.5 meq/kg after 90 days storage at $35^{\circ}C$. AV and TBA were also same trend but the gap with the control was not so big. The Yukwa, $N_2$ gas substituted, was better in quality than absorbent treatment in sensory evaluation and no difference was detected in quality of 90 days storage Yukwa at $35^{\circ}C$ with 15 days. The main reason for lower sensory score of absorbent treatment was that the $O_2$ absorbent also absorbed the flavor component of Yukwa.