• International Journal of Highway Engineering
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• v.13 no.4
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• pp.133-142
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• 2011

The objective of this study is to validate the number of gyrations of Superpave gyratory compactor(SGC) for compaction of hot-mix asphalt (HMA) and warm-mix asphalt(WMA) mixtures. Marshall compaction was also used for comparison purpose. The 13mm and 19mm aggregates of 1st class quality shape were used. A PG64-22 and a PG76-22 for HMA and a PG70-22 for WMA. Four compaction temperatures based on the suggested value were used for each binder using 100 gyrations for SGC and 75 blows per side for Marshall compactor. It was found that SGC compaction was somewhat better than Marshall compaction. The analysis of variance showed that two compactors were significantly different in air voids of 19mm mixtures at ${\alpha}=0.05$ level. The 13mm mixture did not show a significant statistical difference. When compacted at the temperature below a certain level, however, the compaction of two compactors were fond to be proor. Therefore, observing compaction temperature above the minimum level is important to secure proper compaction work. If the minimum temperatures were maintained, 100 gyrations, which was given for HMA of arterial road pavement by the Korean Guide, was found to be appropriate compaction, showing similar or better compaction work than 75 blows per side of Marshall compaction.

• Korean journal of food and cookery science
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• v.20 no.6 s.84
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• pp.695-707
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• 2004

As a result of the additiong of dietary polysaccharides, such as dextran, xanthan gum, gum guar, and gellan gum, differences were observed in the viscosities of the batter for Jeung according to the polysaccharides and theiramounts added, but the pH was not significantly different. The specific volume was highest, in Jeung-pyun with the addition of $0.1\%$ gum guar, at 2.08. The greater the amount of dextran added, the higher the observed specific volume, but the greater the addition of gellan gum, the lower the observed specific volume. The results wereas similar with regard to the expansion characteristics and air holes. As a result of analyzing the texture, the Jeung-pyun with the addition of 1.2 and $3.0\%$ dextran proved to be significantly lower than the control group in terms of hardness, gumminess and chewiness. In the sensory evaluation, the acceptability of Jeung-pyun with the addition of $0.1\%$ gum guar ranked highest, at 8.00, in overall desirability and that with the addition of gellan gum ranked lowest, regardless of the amount added. When 1, 5 and $10\%$ soybean were to Jeung-pyurl, the viscosities increased from those in the early stage in relation to the amount of added, the greater the addition of soybean, the higher the overall pH, but during the fermentation process. the pH decreased. In the group with the addition of $1\%$ soybean the best results infor specific volume, grain and air holes were observed to be the most desirable, proved to be the softest after analysinganalyzing for texture and ranked highest in the sensory scores.

• Particle and aerosol research
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• v.15 no.4
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• pp.191-202
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• 2019

In this study, performance (particle removal efficiency and breathing resistance) of several commercially available face masks (electrostatic filter masks (KF80 certified), a nanofiber filter mask (KF80 certified), and an uncertified mask) with their filter structure and composition were evaluated. Also, effects of relative humidity (RH) of incoming air, water and alcohol exposure, and reusability on performance of face masks were examined. Monodisperse and polydisperse sodium chloride particles were used as test aerosols. Except the uncertified mask filter, PM_2.5 removal efficiency was found to be higher than 90%, and the nanofiber filter mask had the highest quality factor due to the low pressure drop and high removal efficiency (nanofibers were arranged in a densely packed pore structure and contained a significant amount of fluorine in addition to carbon and oxygen). In the case of the KF80 certified mask, the removal efficiency was little affected when the RH of incoming air increased. When the mask filters were soaked in water, the removal efficiency of mask filters was degraded. In particular, the uncertified mask filter showed the highest removal efficiency degradation (26%). When the mask was soaked in alcohol, the removal efficiency also decreased with the greater degree than the water soaking case. The nanofiber mask filter showed the strongest resistance to alcohol exposure among tested mask filters. During evaluation of reusability of masks in real life, the removal efficiency of certified mask filter was less than 4% for 5 consecutive days (2 hours per day), while the removal efficiency of uncertified mask filter significantly decreased by 30% after 5 days.

• Korean Journal of Food Science and Technology
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• v.51 no.1
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• pp.29-34
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• 2019

In this study, a commercial production stepwise method for restorative rice with high quality and microbial safety was developed. The stepwise treatment method included steaming, refrigerated aging, and low temperature drying. The soaking rice was steamed twice at $90-100^{\circ}C$, and then, the rice was aged at $0-10^{\circ}C$, frozen at $-20^{\circ}C$, and dried at low temperatures with 5 m/s wind speed at $1-20^{\circ}C$ and 85% relative humidity. Applying the three steps improved sensory qualities compared with the conventional hot air drying and made storage at room temperature for 3 months possible. Specifically, the moisture content of the restorative rice was increased to 30%, which was 4.3 times higher than the 7% of the conventional air dried rice, and the rice grain shape was well maintained. The texture and appearance of the three-step rice were significantly improved (p<0.05) in a sensory evaluation.

• The Journal of the Acoustical Society of Korea
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• v.28 no.8
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• pp.781-789
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• 2009

The absorption coefficients of the materials used in a 1:50 scale model multipurpose hall were measured based on ISO 354 and related laws. The shape and materials for the scale model were evaluated based on reflective surfaces, variable acoustic elements and sound-absorbing quality (125Hz-1kHz average) of seats. The measured average absorption coefficients of audience seats, audience and orchestra were 0.64, 0.74 and 0,45, respectively, which were simulated with the combination of wood, absorption materials and foam board. Various mounting methods for absorption curtain and banner were considered according to the installation methods. The average absorption coefficient was measured as 0.42, 0.47 and 0.45 in the conditions of Type A mounting, E mounting with 0.9 m backing air cavity, and Type G mounting which is suspended at the ceiling, respectively. It was confirmed that the absorption coefficient was increased at low frequency by backing air gap. The finishing material of stage house was an absorption material covered with thin fabric, which aimed average absorption coefficient of 0.68 by using fiber glass board. Each part of the real materials was compared with those of 1:50 scale model and it was found that the absorption characteristics of both cases were similar.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.26 no.6
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• pp.33-50
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• 2023

This study is to propose the ecosystem service valuation method as a complementary or alternative tool to overcome the limitations of the contingent valuation method(CVM), typically used to assess social benefits in preliminary feasibility studies. With an increasing interest in natural and environmental restoration projects, we assessed social benefits with theses CVM and ecosystem service valuation method from a case of Janghang wetland restoration project and compared the extent of the two social benefits. For quantitative evaluation of ecosystem services, the biophysical quantity for each ecosystem service indicator was calculated and then converted into currency (KRW) units to estimate the economic value of ecosystem services. The four ecosystem regulating service indicators were selected including greenhouse gas capture/storage, air pollution, water quantity and quality regulation. The amounts of CO₂ sequestration and storage as a ecosystem's greenhouse gas regulating service in the study area were 73.04 tCO₂/yr and 5,867.53 tCO₂/yr respectively. The reduction of SO₂, one of air pollutant gases by ecosystems was calculated to be 180.27 kg/yr, the reduction of NO₂ to be 378.90 kg/yr, and the reduction of fine dust (PM10) to be 9,713.92 kg/yr. The amount of freshwater regulating service by the ecosystem was estimated to be 459,394,319ℓ/yr, and the amount of nitrogen in freshwater removed by the ecosystem was 78.00kg/yr. Study results show that the benefits derived from the CVM were KRW 227.8 billion over the 30-year analysis period and those from the ecosystem service valuation method were KRW 41.4 billion for regulatory services and KRW 148.8 billion for cultural services, totaling KRW 189.5 billion. With KRW 184.8 billion of the total costs, the benefit/cost ratio using the CVM was 1.23 and that with the ecosystem service valuation method was 1.03. This study implications include that the CVM and ecosystem service valuation method can be applied together to assess and compare social benefits for natural and environmental restoration projects.

• Journal of the Korea Concrete Institute
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• v.23 no.5
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• pp.541-550
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• 2011

Many researches have been performed on concrete with fly ash and bottom ash. However researches on concrete with pond ash (PA) and its application to RC (Reinforced Concrete) structure are limitedly carried out. This paper presents an applicability of PA concrete in construction of real size structure. Referring to the previous study, 2 domestic PA samples with normal performance are selected and 2 replacement ratios (25% and 50%) to fine aggregate are considered for 5 PA concrete structures consisting of column, slab, and wall. In order to evaluate the property of fresh concrete, several tests including air content, slump, and setting time are performed. Using cored out samples from hardened PA concrete structure, tests for strength, resistance to carbonation and chloride penetration are carried out and compared with control samples. Additionally, tests for rebound hardness, drying shrinkage, and hydration heat are performed for PA concrete structure. The test results showed that PA concrete has reasonable strength and durability performances compared to those of normal concrete. Therefore, its potential application to RC structure is promising. The PA aggregate can be more actively used for RC structures with better quality control for content of fly ash, bottom ash, and unburned carbon.

• Journal of Animal Science and Technology
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• v.50 no.1
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• pp.133-144
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• 2008

Four different pork patties were made with two levels, HP/FP-3% and HP/FP-6%, containing 3.0 and 6.0% HP(hot air dried sweet persimmon powder)/FP(freeze-dried sweet persimmon powder), respectively. After manufacture, the meat patties were packaged with  polyvinyl wrap and stored at 4℃ for 8 days. CTL(control) and HP-3% meat patties were significantly(p<0.05) higher in moisture content than the other samples. FP-6% was found higher in protein content than the other treatments. FP-3% had a higher fat content than other meat patty samples. However, ash contents were not found significantly(p>0.05) different among the meat patty samples. The value of pH, L* and a* values were decreased as the cold storage time increased in all treatments(p<0.05). WHC(water holding capacity) of CTL and HP-6% and cooking loss of HP-3% were significantly(p<0.05) decreased with increased storage period. The diameter and thickness of all meat patties decreased with increasing the storage period. VBN(volatile basic nitrogen) values of all meat patties were increased(p<0.05) with increased storage period. TBARS (thiobarbituric acid reactive substance) of treatments were higher than that of CTL during whole storage time. The number of microorganisms(Total plate counts, Escherichia coli.) were maintained below 4.61 log10 CFU/cm2 during the whole storage period. In sensory evaluation, treatment groups had higher(p<0.05) scores in aroma, flavor, color and overall acceptability.

• Journal of Nutrition and Health
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• v.49 no.1
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• pp.43-50
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• 2016

Purpose: This study was conducted to examine prerequisite-program performance of the hospital foodservice operation and develop measures for improvement of prerequisite-program performance. Methods: Data were collected through surveys administered to 168 hospital dieticians in the Seoul, Incheon, Gyeonggi-do, Daegu, and North Gyeongsang areas. Out of total questionnaires, 65 questionnaires were usable and the response rate was 38.7%. Statistical analyses were performed using the SPSS program (ver 20.0) for ${\chi}^2-test$ and one-way ANOVA. Results: According to the result of the prerequisite-program evaluation, the percentage of 'appropriate', 'needs to be improved', and 'inappropriate' was 44.6%, 47.7%, and 7.7%, respectively. The score for the 'inappropriate' group was significantly lower than that of the 'appropriate' group or 'needs to be improved' group on the food safety management (p < 0.001), preparation facility management (p < 0.001), water management (p < 0.001), and storage transportation management (p < 0.05) parts. Holding rate of foodservice facility and equipments in the 'appropriate' group were significantly higher than in the others on convection oven (p < 0.01), air conditioner (p < 0.01), three-compartment sink (p < 0.01), hot-holding equipment (p < 0.01), cold-holding equipment (p < 0.05), exclusive thawing refrigerator (p < 0.05), and sterilizer for sanitary shoes (p < 0.05) items. Conclusion: To improve the quality of hospital foodservice, foodservice managers and HACCP specialists should develop and implement a prerequisite-program and a HACCP plan considering the characteristics of the hospital foodservice operation.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.276-276
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• 2017

This study was examined to establish a conditions for producing Tteokbokki using dry-milling rice flour which can save manpower and labor time. Since the cost of producing rice flour milled in a wet condition is 500 to 700 won/kg, which is more than twice as much as that of 300 won wheat flour, it is necessary to directly make rice flour from raw rice. The dry-milling rice flour used in the experiment was produced by Air mill (Nara machinary co. ltd., Tokyo, Japan) from 5 rice cultivars (Samkwang, Dasan-1, Boramchan, Seolgaeng, Hanareum-2), which were cultivated in A-san in 2015 year. Their particle sizes were 50, 100 and $150{\mu}m$ for each cultivar, respectively. A control was a wet-milled rice flour milled with a roll mill after the rice was soaked in water for 4 hours. The moisture content of dry-milling rice flour based on cultivars was 11 ~ 12%, and added water up to 50~55% of dry-milling rice flour weight. The RVA characteristic of peak viscosity was the highest in Dasan-1 and Hanareum-2, the lowest in Seolgaeng. The setback value used as an indicator of aging was the highest in Dasan-1, therefore Dasan-1 was expected to be quick solidification, resulting in the low tendency of sensory evaluation. The damaged starch was high in Dasan-1 and Boramchan (p<0.05) compared to others. The Hunter color L were no significant among cultivars and b value increased in all cultivars of dry-milling rice flour compared with control. The hardness of dry-milling rice flour was higher than that of the control, especially Dasan-1 and Hanareum-2 were the highest. Based on the sensory evaluation, the best cultivars were Boramchan, Hanareum-2 and Samkwang. The overall preference of dry-milling rice flour was good in particle size of 50~100um.