• Journal of Radiation Protection and Research
• /
• v.34 no.4
• /
• pp.190-194
• /
• 2009

Gamma spectral results for macroalgae samples taken from the environment of Ulchin nuclear power plants in Korea (east coast), showed 766 keV peaks, which were identified as $^{95}Nb$ by several research institutes. After the enhancement of liquid radioactive waste disposal facility at Ulchin NPP site, the $^{95}Nb$ amount in the liquid radioactive waste outflow has drastically reduced, but the expected reduction in $^{95}Nb$ specific activity from environmental samples did not actually show up on gamma spectroscopy. Detailed re-investigation revealed that along with 766 keV peak, other peaks (63, 92 and 1001 keV) from $^{234}Th-^{234}mPa$ decay series were also detected on spectroscopy, and that the measured half lives of the four peaks were very close to known half life of $^{234}Th-^{234}mPa$ decay series, which is 24.1 day. The measured gamma yield ratios of 766 keV peak to 1001 peak were very close to known ratio 0.35 for $^{234}mPa$. It is concluded that 766 keV peaks on gamma spectroscopy of Ulchin NPP environmental samples were mainly from $^{234}mPa$, which is one of naturally occurring radionuclides.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.4 no.2
• /
• pp.82-89
• /
• 2009

According to the great city development and the rapid growth of redevelopment project, waste concrete emission has been increased. Waste concrete powder is one of the by-product originated from the recycling of the waste concrete. The more making high quality recycled aggregate to use aggregate for concrete, the more waste concrete powder is producted relatively. Therefore, to realize the total recycling of waste concrete, development of recycling technology for waste concrete powder need very much. This technical note present the discharged process and the various properties of waste concrete powder. As the results, on the average, the maximum particle-size of waste concrete powder is less than $600{\mu}m$, and oven-dry density is less than $2.5g/cm^3$. And waste concrete powder contains more than 50% of $SiO_2$, 30% of CaO and 10% of $Al_2O_3$. Thus qualities of waste concrete powder is lower than those of high quality raw material for concrete. However, if it is processed by grading to the purpose, it will be used as resource of raw materials for construction field.

• Journal of the Korean Electrochemical Society
• /
• v.2 no.4
• /
• pp.183-189
• /
• 1999

A study on the destruction of organic cation and anion exchange resins by electro-generated Ag(II) as a mediator was carried out to develop the ambient-temperature aqueous process, known as Ag(II)-mediated electro-chemical oxidation (MEO) process, for the treatment of a large quantity of spent organic ion exchange resins as the low and Intermediated-level radioactive wastes arising from the operation, maintenance and repairs of nuclear facilities. The effects of controllable process parameters such as applied current density, temperature, and nitric acid concentration on the MEO of organic ion exchange resins were investigated. The cation exchange resin was completely decomposed to $CO_2$. The current efficiency increased with a decrease in applied current density while nitric acid concentration and temperature on the MEO of cation exchange resin did not affect the MEO. On the other hand, anion exchange resins were decomposed to CO and $CO_2$. The ultimate conversion to CO was about $10\%$ regardless of temperature. The destruction efficiencies to $CO_2$ were dependent upon temperature and the effective destruction of anion exchange resin could be obtained above $60^{\circ}C$.

• Applied Biological Chemistry
• /
• v.51 no.1
• /
• pp.11-16
• /
• 2008

The extraction conditions for resveratrol production from grape fruit stem, which is a by-product of grape processing, were optimized to develop high-functional grape-based products. Additionally, the bioefficacy of grape fruit stem extract (GFSE) as an antioxidant agent was evaluated. Resveratrol was extracted using various experimental conditions such as extractant type, extractant concentration, raw material-extractant ratio, extraction time and temperature, and the results were analyzed using a statistical program (SPSS). The resveratrol yield was the highest when 80% ethanol with a raw-material-extractant ratio of 1:10 (w/v) was used. In addition, the optimal temperature and time were selected as $60^{\circ}C$ and 90 min, respectively. When the antioxidant activity was analyzed and expressed as DPPH radical scavenging activity and SOD-like activity, the antioxidant activity of GFSE was higher than that of BHT, BHA and L-ascorbic acid. Finally, it was found that GFSE could be used as a raw material for the production of high antioxidant agents.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.20 no.4
• /
• pp.35-43
• /
• 2016

Recently, the pipeline system for waste transportation has been increasingly constructed as new solution for the waste collection and disposal system by constantly increasing domestic waste which issued as social problem. The pipeline system is constructed through long distance, so proper long-term monitoring system is necessary which available to detect the damage location for the effective maintenance. In this paper, the experimental study is carried out to evaluate the applicability of optical strain gauge sensor based on FBG for the long-term monitoring system. Three test parameters such as pressure leaking, blockage and deformation are considered as typical damages for real-scale pipeline test specimen. In order to measure flexural and volumetric strain and temperature, three FBG sensors are installed at each monitoring sections. From the test results, this study suggested effective methods of sensor installation and arrangement. Also the sensor spacing for the design of monitoring system using FBG sensor is derived by the correlation of distances from deformation between sensor responses.

• Journal of the Korean Society of Groundwater Environment
• /
• v.6 no.3
• /
• pp.120-125
• /
• 1999

This study was carried out to enhance the efficiency of bioleaching of heavy metals. copper and zinc from the soil samples obtained from mine tailings in Cho-il Mine located in Dan-Yang, Choong-Buk. The effects of medium (9 K) composition on the leaching efficiency were investigated by changing concentrations of the dominant components. phosphorus, nitrogen source. and energy source which are the most important factors governing the growth and multiplication of microorganism. The results of the bioleaching test at different phosphorus concentrations of medium, 0 mM. 3.0 mM, and 6.0 mM showed that leaching efficiency for zinc and copper was 98.8% and 47.5% respectively at 0 mM and decreased at higher phosphorus concentration 6.0 mM. In the bioleaching test of zinc and copper at 0 mM, 45 mM, and 90 mM nitrogen concentrations, the Highest efficiency of 85% and 46.4% was obtained for zinc and cooper respectively at 45 mM and the lower efficiency observed for 90mM nitrogen addition. The zinc and copper leaching with variation of energy source dosage showed the highest removal efficiency, 93% for zinc in the absence of energy source and 46.4% for copper at 160mM energy source.

• The Korean Journal of Soil Zoology
• /
• v.7 no.1_2
• /
• pp.17-21
• /
• 2002

Food waste which had been mixed with night soil sludge and composted for 21 days (mixing ratio = food waste/paper mill sludge : 1, w/w) was supplied to the 5 g of Eisenia fetida popualtion at various temperatures (5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 31, 32, 33, 34, 35$^{\circ}C$). The biomass of earthworms one month after feeding at 20-32$^{\circ}C$ was about two times more than that of the introduced earthworms, increasing rate of which was much higher than them at the other tested temperatures . There were decreases at temperatures below 7$^{\circ}C$, and less increases at temperatures of 8-10$^{\circ}C$ in biomass. Earthworms could not survive at temperatures at 34$^{\circ}C$ and 35$^{\circ}C$. Feeding rates of earthworms were much higher at 20-32$^{\circ}C$ than them at the other tested temperatures, and there were no differences among them at temperatures of 20-32$^{\circ}C$. But at 3 months after feeding, the biomass and feeding rate of earthworms decreased severely even at 20$^{\circ}C$ and 30$^{\circ}C$, which was supposed to be due to the long term effect of salts, especially sodium chloride (NaCl) in the food wastes.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.31 no.1 s.49
• /
• pp.121-125
• /
• 2005

Most of the cells, specially in the skin, free radicals and reactive oxygen species induced aging, accompanying with diseases. The pinaceae family is very familiar plant with Korean spirit. However, those plants were not estimated for natural products in manufactural process. We employed 4 different plants, Pinus koraienis S et Z. Pinus banksiana LAMBERT. Pinus rigida MILL. Pinus densiflora S. et Z. in pinceae family. The ethanol extracts were prepared for three different parts of plant, wood, bark and leaf, respectively. In this study, we carried out free radical and superoxide radical scavenging assay to investigate the anti-oxidative activity The bark and leaf part of plants showed similar anti-oxidant effect. L-ascorbic acid and $\alpha$-tocopherol at $10{\mu}g/mL$. Also we tried to investigate inhibitory effects of elastase activity in in vitro experiments on pinaceae plant extract as a matters for functional cosmetics. Among those plants, the bark of Pinus rigida MILL. and Pinus densiflora S. et Z. showed inhibitory effect. The cell viability was evaluated with MTT assay. The potential relationship was shown between the cell viability and anti-oxidant effect because the anti-oxidant effects were positively correlated wvith the cell growth in MTT assay. As the results in our experiments, we expect the potential activities of pinaceae as a material of functional cosmetics.

• Korean Journal of Soil Science and Fertilizer
• /
• v.44 no.5
• /
• pp.903-915
• /
• 2011

Recently, anaerobic methane production of agricultural waste biomass has received increasing attention. Until now domestic BMP (Biochemical methane potential) studies concerned with agricultural waste biomass have concentrated on the several waste biomass such as livestock manure, food waste, and sewage sludge from WWTP (Waste water treatment plant). Especially, the lack of standardization study of BMP assay method has caused the confused comprehension and interpretation in the comparison of BMP results from various researchers. Germany and USA had established the standard methods, VDI 4630 and ASTM E2170-01, for the analysis of BMP and anaerobic organic degradation, respectively. In this review, BMP was defined in the aspect of organic material represented as COD (Chemical oxygen demand) and VS (Volatile solid), and the influence of several parameters on the methane potential of the feedstock was presented. In the investigation of domestic BMP case studies, BMP results of 18 biomass species generating from agriculture and agro-industry were presented. And BMP results of crop species reported from foreign case studies were presented according to the classification system of crops such as food crop, vegetables, oil seed and specialty crop, orchards, and fodder and energy crop. This review emphasizes the urgent need for characterizing the innumerable kind of biomass by their capability on methane production.

• Korean Journal of Remote Sensing
• /
• v.37 no.2
• /
• pp.233-243
• /
• 2021

Photovoltaic panels are hazardous electronic waste that has heavy metal as one of the hazardous components. Each year, hazardous electronic waste is increasing worldwide and every heavy rainfall exposes the photovoltaic panel to become the source of heavy metal soil contamination. the development needs a monitoring technology for this hazardous exposure. this research use relationships between SAR temporal baseline and coherence of Sentinel-1 satellite to detected photovoltaic panel. Also, the photovoltaic plant detection tested using the difference between that photovoltaic panel and the other difference surface of coherence. The author tested the photovoltaic panel and its environment to calculate differences in coherence relationships. As a result of the experiment, the coherence of the photovoltaic panel, which is assumed to be a permanent scatterer, shows a bias that is biased toward a median value of 0.53 with a distribution of 0.50 to 0.65. Therefore, further research is needed to improve errors that may occur during processing. Additionally, the author found that the change detection using a temporal baseline is possible as the rate of reduction of coherence of photovoltaic panels differs from those of artificial objects such as buildings. This result could be an efficient way to continuously monitor regardless of weather conditions, which was a limitation of the existing optical satellite image-based photovoltaic panel detection research and to understand the spatial distribution in situations such as photovoltaic panel loss.