Journal of the Society of Cosmetic Scientists of Korea
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v.39
no.2
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pp.149-158
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2013
L-ascorbic acid, the representative antioxidants, has a great effect on skin whitening, collagen synthesis, and anti-aging, but has low oxidative stability during storage. Therefore, in this study, thermal and oxidation properties of L-ascorbic acid under various storage conditions (powder, aqueous phase, changes of temperature, UV-irradiation, and inflow of external air etc.) were investigated. And the storage stability of ingredient was validated in the double-spaced pouch by analysing oxidation properties under each storage conditions (powder phase and blended with essence). In oder to analyze the thermal properties, TGA, DSC, and FT-IR analysis were carried out and UV-visible spectrophotometer & redox titration were used in parallel for oxidation property analyses. From the result of experiment, L-ascorbic acid was oxidized fast when it contained lots of metallic ion, hydroxy ion in aqueous solution under high temperature, UV-irradiation & inflow external air, whereas it was not oxidized for a long time when it was stored as pure powder although it has same condition as heating up, UV-irradiation & inflow external air. Based on this result, retention period of cosmetics which is using L-ascorbic acid, less stable material in oxidation can be innovatively increased when using double-spaced pouch that is designed and produced for separating storage of active ingredients.
Magazine of the Korean Society of Agricultural Engineers
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v.35
no.2
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pp.92-103
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1993
A sunday system with a horizontal bin-type composter was constructed and operated to evaluate its composting performance for four days for each test in October, 1992. A sundry system is one of popular systems for composting livestock manure, of which main benefit is to utilize unlimited, clean, and free solar radiation. A rectangular concrete bin(composter) with dimension of 300cm(length) X90cm(width) X60cm(height) was bedded alternatively with four lanes of aeration pipes and heating pipes, and was insulated at three walls with 50mm styrofoam. Each aeration pipe of a diameter of 25mm had 4mm perforated holes at every 15cm longitudinally, and supplied air of about 2m$^3$/min to the composter to maintain aerobic condition . A stirrer rotating at 1 rpm made one round trip every 20 minutes on the conveying chain along the the length of the composter. Five tests (Test 1~Test 5) were implemented to evaluate the composting effectiveness of a sundry system with a horizontal bin-type composter. Treatments of two levels of the mixture ratio of swine manure and paper sludge cakes(manure : paper sludge cakes= 1 : 4 and 1 : 2) and two levels of the water content(W/C ; 70% and 50%) were made to test the significance of the physicochemical properties for decomposition of the mixture materials. Temperature, C/N ratio, water content, microbial activity of the composting materials were taken measurements to evaluate its performance with the lapse of composting time for tests. A small-scale sundry system with a bin-type composter did not appear to be an appropriate system for composting livestock manure. Since heat generation by the composting materials could not overcome heat loss due to areation in a small-scale composter, a proper thermal enviroment could not be maintained to propagate massively thermopilic microorganism relatively in a short period of time. Different from the result of Chol et al.(1992) 6), a temperature variation of the composting materials did not show the peak clearly and C/N ratio didn't lower with time as expected. Mesophilic microoragnism seemed to play an important role for decomposition of the mixture materials. A sundry system with a bin-type composter may be good for a large-scale livestock farm household which may produce enough animal manure. Therefore a decision should be made very carefully to choose a system for composting livestock waste.
The mutagenicity of the thermally oxidized soybean oils was investigated. Each oil sample was taken after 0, 8, 16, 24, 32, 40, and 48 hours of heating at a temperature of $180{\pm}3^{\circ}C$, and was used to study the changes of peroxide value(POV), acid value(AV), iodine value(IV), conjugated dienoic acid content(CDA content, %), and fatty acid composition. Another set of samples was fractionated into non-oxidized and oxidized fractions by column chromatography using silica gel. The mutagenicity of the samples taken from the thermally oxidized oils as well as the non-oxidized and oxidized fractions was investigated with the Ames test. Bacterial tester strains used in the present study were the histidine auxotrophic strains of S. typhimurium TA100, TA1535 and TA 102 for the detection of base pair, and TA98 and TA1537 for frame shift mutations. Each set of samples was dissolved in tetrahydrofuran and tested at doses ranging from 0.05 to 5 mg/plate. The oxidized fractions increased significantly the number of $His^+$ revertant colonies of TA100, TA1537 and TA102, thereby showed mutagenic activity on these strains. However none of the oil samples taken within the 48 hours oxidation period showed any mutagenic activity with and without metabolic activation.
Seasoning gochujang sauces were prepared with 0, 10, 20 and 30% concentrated heating chopped garlic (garlic base) and analyzed. These seasoning gochujang storage for 40 days at $37{\pm}1^{\circ}C$ and examined for changes in their physicochemical properties. Hunter color L and b-value of seasoning gochujang were decreased slowly till 20 days of storage then increased afterward. The highest pH of the seasoning gochujang was pH 5.22 in the 30% garlic base added group. The titratable acidity increase significantly till 40 days of storage. As the adding ratio of garlic base increased, reducing sugar content was decreased. The amino-nitrogen content was continually decreased during aging up to 40 days. ABTs radical scavenging activity was increased as garlic base addition level was increased. The activity was decreased with passing by storage period, and below 50% at 40 days storage.
Number of crop residues generated at large amount in agriculture can be utilized as substrate in methane production by anaerobic digestion. Greenhouse vegetable crop cultivation that adopting intensive agricultural system require the heating energy during winter season, meanwhile produce waste biomass source for the methane production. The purpose of this study was to investigate the methane production potential of greenhouse vegetable crop residues and to estimate material and energy yield in greenhouse system. Cucumber, tomato, and paprika as greenhouse vegetable crop were used in this study. Fallen fruit, leaf, and stem residues were collected at harvesting period from the farmhouses (Anseong, Gyeonggi, Korea) adopting an intensive greenhouse cultivation system. Also the amount of fallen vegetables and plant residues, and planting density of each vegetable crop were investigated. Chemical properties of vegetable waste biomass were determined, and theoretical methane potentials were calculated using Buswell's formula from the element analysis data. Also, BMP (Biochemical methane potential) assay was carried out for each vegetable waste biomass in mesophilic temperature ($38^{\circ}C$). Theoretical methane potential ($B_{th}$) and Ultimate methane potential ($B_u$) off stem, leaf, and fallen fruit in vegetable residues showed the range of $0.352{\sim}0.485Nm^3\;kg^{-1}VS_{added}$ and $0.136{\sim}0.354Nm^3\;kg^{-1}VS_{added}$ respectively. The biomass yields of residues of tomato, cucumber, and paprika were 28.3, 30.5, and $21.5Mg\;ha^{-1}$ respectively. The methane yields of tomato, cucumber, and paprika residues showed 645.0, 782.5, and $686.8Nm^3\;ha^{-1}$. Methane yield ($Nm^3\;ha^{-1}$) of crop residue may be highly influenced by biomass yield which is mainly affected by planting density.
In this study, the research objects are gilt plated silver-iron nails excavated from the west of the tombs in Neungsan-ri, Buyeo. A gilt plated silver-iron nail was fabricated by combining silver and iron via heating and then gilding amalgam on top of this combination, demonstrating that this ancient artifact that can be replicated using current technology. Since the metal (Au, Ag) surface of these gilt plated artifacts are covered with iron oxide, which slips into the cracks and scratches of the artifacts as well, desalination is essential. Based on the results of the preliminary experiment, the research objects were classified into grades A, B, and C, according to the degree of corrosion and then desalinated using an alkali solution (NaOH, Sodium Sesquicarbonate of 0.1 M) at 60℃. The results demonstrate that the more serious is the degree of corrosion, the more is the amount of Cl- detected. Further, more Cl- was released when NaOH was used than when sodium sesquicarbonate was used, for all grades except Grade A. Furthermore, the more serious is the degree of corrosion, the longer is the desalination period and the reaction with NaOH for all grades except Grade A. A comparison of the Fe composition of the surface before and after desalination shows that Fe composition is the use of NaOH resulted in a smaller increase compared with the use of sodium sesquicarbonate, for all grades except Grade B. However, four of the nails were damaged owing to NaOH (Grade B 3ea, Grade C 1ea) during desalination. Thus, Cl- ions are more stably released when sodium sesquicarbonate is used than when NaOH is used.
Journal of Environmental Analysis, Health and Toxicology
/
v.21
no.4
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pp.220-228
/
2018
$PM_{2.5}$-bound mercury (PBM) was monitored at weekly intervals for three years (from 2014 to 2016) at an urban (Seoul) and rural site (Baengnyeong) in South Korea. The average PBM concentrations in $PM_{2.5}$ samples over the entire sampling period were $12{\pm}11pg/m^3$ and $36{\pm}34pg/m^3$ for Baengnyeong and Seoul, respectively. Seasonal differences were pronounced, with concentrations being highest in winter due to local meteorological conditions (high gas-particle coefficient due to low temperature and low mixing layer height in winter) as well as seasonal factors, such as coal combustion for heating purposes in China. In Baengnyeong, the significant positive correlation of PBM with $PM_{2.5}$, air pollutants, and heavy metals suggested that coal combustion in China might be the most important source of ambient mercury in Korea. In winter, no correlation of PBM with $PM_{2.5}$, air pollutants, and heavy metals was seen in Seoul. Furthermore, Seoul showed higher $PBM/PM_{2.5}$ and $Pb/PM_{2.5}$ ratios in winter due to the strong atmospheric oxidation-reduction reaction conditions as well as local and regional PBM sources. We conclude that immediate attention must be given to addressing PBM levels in Korea, including considering it as a key component of future air quality monitoring activities and mitigation measures.
Journal of the Korean Society for Geothermal and Hydrothermal Energy
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v.19
no.3
/
pp.1-13
/
2023
Hydronic heated road pavement (HHP) systems have been well established and documented to provide road safety in winter season over the past two decades. However, most of the systems run on asphalt, only a few are tested with concrete, and there rarely is a comparison between those two common road materials in their performance. The aim of this study is to investigate the thermal performance of the concrete HHP systems, including surface temperature variations of experimental pavements in winter season. For preliminary study a small-scale experimental system was installed to evaluate the heat transfer characteristics of the concrete HHP in the test field. The system consists of 3 concrete slabs made of 1 m in width, 1 m in length, and 0.25 m in height. In these slabs, circulating water piping was embedded with different pipe depths of 0.08 m (Case A), 0.12 m (Case B), and 0.20 m (Case C) and same horizontal space of 0.16 m. Heating performance in winter season was tested with different inlet temperatures of 25℃, 30℃, 35℃ and 40℃ during the entire measurement period. Overall, the surface temperature of the concrete HHPs remained above 3℃ in all experimental conditions applied in this study. The results of the surface temperature measurement with respect to the pipe depth showed that Case B was the highest among the three cases. However, the closer the circulating water pipe was to the pavement surface, the greater the heat exchange rate. This results is considered that the heat is continuously accumulated inside the pavements and then the temperature inside the pavements increases, while the amount of heat dissipation decreases as the temperature difference between the inlet and outlet of circulating water decreases. In this preliminary test the applicability of the concrete HHP on road deicing was confirmed. Finally, the results can be used as a basis for studying the effects of various variables on road pavements through numerical analysis and for conducting large-scale empirical experiments.
Journal of the Korean Association of Geographic Information Studies
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v.27
no.3
/
pp.43-59
/
2024
This study focuses on identifying the impacts of the Nowon resource recovery facility in Seoul, Korea, on the real transaction price of apartments in the neighboring areas between 2006 and 2022, and the spatial extent of the impact. Resource recovery facilities, which generate electricity and heating energy while disposing of waste, are typical unwanted facilities that have a negative impact on neighboring property prices. As direct landfilling of household waste is banned in Seoul from 2026 and nationwide from 2030, the demand for the expansion of waste incineration facilities, including resource recovery facilities, is expected to increase rapidly. In addition, social disputes related to the decline in neighboring property prices are expected to increase. This study analyses the impact of the Nowon resource recovery facility on surrounding apartment prices over a 17-year period since 2006 using hedonic price models for apartments, and finds that the Nowon resource recovery facility consistently has a negative impact on nearby apartment prices, the spatial extent of the impact is at least 1,000 meters from the facility, and the intensity of the negative impact weakens as the distance from the facility increases. The results of this study differ from recent studies finding that the spatial extent of the impact of resource recovery facilities in Seoul on surrounding property prices is limited within 500~600 meters, suggesting that a broader approach is needed to systematically manage social conflicts that are expected to increase with the growing social demand for resource recovery facilities.
The thermal filter press dewatering(TFPD) technology to improve the dewaterability through increasing the inner vapor pressure, lowering the filtration viscosity and forming the porosity easily within cake as applying the heat at the sludge layer was developed in this study. The hot water with temperature of $95^{\circ}C$ and pressure of $1.2kg_f/cm^2$ was supplied to the heating plate equipped between filter plates with plate size of $470{\times}470mm$ and material of polypropylene. Sludge was dewaterd by supplying pressure of $5kg_f/cm^2$ and then by squeezing pressure of $15kg_f/cm^2$. As a results of estimating the characteristics of thermal dewatering to consider the initial water content and organic content to be influenced by a period of water shortage and rainwater, the dewatered cake water content was about 35 wt% and dewatering velocity was $4DSkg/m^2{\cdot}hr$ under the rainwater period, and the dewatered cake water content was about 50 wt% and dewatering velocity was $1.5DSkg/m^2{\cdot}hr$ in the case of sludge of water shortage season. These results was superior to the mechanical dewatering performance with water content of 70wt% and dewatering velocity of $0.9DSkg/m^2{\cdot}hr$. On the base of the results of TFPD, energy consumpted to deal with DS(Dry Solid) of 1kg was estimated by 300 kJ. It was analyzed that the energy consumption of TFPD was decreased about one third with comparison to the dryer system. Dewatering velocity of this technology was faster than the one of mechanical dewatering equipment and it was easier to product low water content cake. Therefore, this technology was recognized that dewaterability was predominant because of the fast of dewatering velocity and production of low water content cake, and also this known as economical efficiency was excellent because of low energy consumption in comparison with dryer.
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