• Journal of Welding and Joining
• /
• v.20 no.1
• /
• pp.47-54
• /
• 2002

Powder type Ag system insert metals were manufactured by ball milling process. The variables of milling process such as milling media, revolution speed and powder/ball weight ratio were constant except the milling time. The milling times were selected for 24, 48 and 72 hours. The insert metals made by milling process were evaluated by performing scanning electron microscope, x-ray and DSC(differential scanning calorimetry) analysis, and further in terms of wettability test. The selected insert metals that have the good characteristics compared to commercial insert metals were applied to make the brazed joints of the steel/steel and the steel/WC superhard particles. The characterizations of those brazed joints were also conducted by microstructural observations, shear tensile tests and microhardness measurements. The results indicated that milling time of 48 hours for making powder type insert metals was the best condition showing the small amount of oxides residue, low wetting angle and stable microstructure. The brazed joints that applied the 48 hours milled insert metal were very sound condition indicating the shear tensile value of $2.29{\times}102$ MPa and the microhardness of 138VHN. Further, the amount of the porosity was appeared to be lower than that of the commercial insert metals.

• Journal of the Korean Dietetic Association
• /
• v.25 no.1
• /
• pp.44-58
• /
• 2019

Predicting the number of meals in a foodservice organization is an important decision-making process that is essential for successful food production, such as reducing the amount of residue, preventing menu quality deterioration, and preventing rising costs. Compared to other demand forecasts, the menu of dietary personnel includes diverse menus, and various dietary supplements include a range of side dishes. In addition to the menus, diverse subjects for prediction are very difficult problems. Therefore, the purpose of this study was to establish a method for predicting the number of meals including predictive modeling and considering various factors in addition to menus which are actually used in the field. For this purpose, 63 variables in eight categories such as the daily available number of people for the meals, the number of people in the time series, daily menu details, weekdays or seasons, days before or after holidays, weather and temperature, holidays or year-end, and events were identified as decision variables. An ensemble model using six prediction models was then constructed to predict the number of meals. As a result, the prediction error rate was reduced from 10%~11% to approximately 6~7%, which was expected to reduce the residual amount by approximately 40%.

• Journal of Biosystems Engineering
• /
• v.35 no.4
• /
• pp.244-249
• /
• 2010

This study was conducted to define the optimal Lycium chinense miller washing method for developing the Lycium chinense cleaner and we analyzed the Lycium chinense miller washing characteristics for removing pesticides and microorganism according to washing methods; habitual washing method, air bubble washing method and nozzle spray washing method. The results were summarized as follows; 1. In case of measuring physical properties according to the varieties, maximum yield strength of Hokwang was 2.562 kgf, minimum yield strength of Hokwang was 0.269 kgf and average yield strength was about 1 kgf. 2. In case of measuring change of bacteria according to washing methods, the number of bacteria of non-washing method was more than the number of bacteria of habitual washing method or mechanical washing method and the number of nozzle spray washing method was least. 3. Ahjoksiseuteurobin of 0.218 ppm was detected in the untreated sample, 0.051 ppm was detected in the habitual washing method, 0.047 ppm was detected in the air bubble washing method and 0.034 ppm was detected in nozzle spray washing method. Every amount detected were less than 2 ppm that is reference value and the detected amount was least in case of nozzle spay cleaning method. Cypermethrin of 0.772 ppm was detected in the non-cleaned sample, 0.089ppm was detected in habitual washing method, 0.26 ppm was detected in the air bubble washing method and 0.292 ppm was detected in the nozzle spray washing method. Every detected amount of Cypermethrin were less than 5 ppm that is reference value and the detected amount was least in case of habitual washing method.

• Korean Journal of Agricultural Science
• /
• v.49 no.2
• /
• pp.317-330
• /
• 2022

Recently, the policy regarding climate change in Korea and overseas has been to promote the utilization of forest biomass to achieve net zero emissions. In addition, with the implementation of the unused forest biomass system in 2018, the size of the Korean market for manufacturing wood pellets and wood chips using unused forest biomass is rapidly expanding. Therefore, it is necessary to estimate the total amount of unused forest biomass that can be used as an energy source and to identify the capacity that can be continuously produced annually. In this study, we estimated the actual forest area that can be produced of logging residue and the potential amount of unused forest biomass resources based on GT (green ton). Using a forest functions classification map (1 : 25,000), 5th digital forest type map (1 : 25,000), and digital elevation model (DEM), the forest area with a slope of 30° or less and mountain ridges of 70% or less was estimated based on production forest and IV age class or more. The total forest area where unused forest biomass can be produced was estimated to be 1,453,047 ha. Based on GT, the total amount of unused forest biomass potential resources in Korea was estimated to be 117,741,436 tons. By forest type, coniferous forests were estimated to be 48,513,580 tons (41.2%), broad-leaved forests 27,419,391 tons (23.3%), and mixed forests 41,808,465 tons (35.5%). Data from this research analysis can be used as basic data to estimate commercial use of unused forest biomass.

• The Korea Journal of Herbology
• /
• v.24 no.4
• /
• pp.63-67
• /
• 2009

Objectives : Quality control for imported medicinal herbs is duty for regulation, however to the best of our knowledge there has been no report regarding quality control of imported ones. Therefore, this study investigated the data of imported ones for monitoring quality issue. Methods : These data are categorized according to item, the amount of import, country, inspection item, suitability, and incongruity reason based on the 248 results performed by KIOM. Results : China is the number one country for import with the value of 73%. Inspected medicinal herbs were 139 species, among them Poria is ranked as top for requested number and the amount of import. The amount of import is similar between high ranking 20 species and low ranking 119 ones, showing high ranking ones are major. The incongruity ratio was 7.7% from the total number of inspected items, the reason for incongruity was excess of tolerable amount of Cd residue. Conclusions : From the data, it is effective way to focus on high ranking herbs for evaluating imported herbs for quality control. The study of mechanism on Cd accumulation and its decrease is essential for environmental matter. And identification and storage for mixed used and easily decomposable herbs are remained for further study. Our study might be small step for showing guideline for proper quality control.

• Journal of Korean Society of Forest Science
• /
• v.102 no.1
• /
• pp.82-89
• /
• 2013

Harvest is one of the major disturbances affecting the soil carbon (C) dynamics in forests. However, researches on the long-term impact of periodic harvest on the soil C dynamics are limited since they requires rigorous control of various factors. Therefore, we adopted a modeling approach to determine the long-term impacts of harvest interval, harvest intensity and post-harvest residue management on soil C dynamics by using the Korean Forest Soil Carbon model (KFSC model). The simulation was conducted on Pinus densiflora S. et Z. stands in central Korea, and twelve harvest scenarios were tested by altering harvest intervals (50, 80, and 100-year interval), intensities (partial-cut harvest: 30% and clear-cut harvest: 100% of stand volume), and the residue managements after harvest (collection: 0% and retention: 100% of aboveground residue). We simulated the soil carbon stock for 400 years for each scenario. As a result, the soil C stocks in depth of 30 cm after 400 years range from 50.3 to 55.8 Mg C $ha^{-1}$, corresponding to 98.1 to 108.9% of the C stock at present. The soil C stock under the scenarios with residue retention was 2.5-11.0% higher than that under scenarios with residue collection. However, there was no significant impact of harvest interval and intensity on the soil C stock. The soil C dynamics depended on the dead organic matter dynamics derived from the amount of dead organic matter and growth pattern after harvest.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.45 no.6
• /
• pp.918-922
• /
• 2016

The objective of this study was to determine the antioxidant and anti-proliferative activities of methanol, ethanol, acetone, and ethyl acetate extracts from oats (Avena sativa L.). Total polyphenol contents of extracts were analyzed by Folin-Ciocalteu assay. The antioxidant activities of extracts were determined by 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities and reducing power. The anti-proliferative activities of colon (HCT116), lung (NCI-H460), and breast (MCF7) cancer cells were investigated. Among solvents, methanol extract showed the highest amount of total polyphenols, which was 8.2 mg gallic acid equivalents/g residue. High levels of ABTS radical [12.1 mg Trolox equivalent antioxidant capacity (TEAC)/g residue] and DPPH radical (4.4 mg TEAC/g residue) scavenging activity and reducing power ($A_{700}=0.39$) were found in methanol extracts. Moreover, methanol extracts indicated higher anti-proliferative activities against HCT116 (69.5%), NCI-H460 (75.2%), and MCF7 (84.8%) cells compared with other extracts. The results show that methanol was the best solvent for extraction of antioxidant and anti-proliferative compounds from oats. Moreover, notable antioxidant and anti-proliferative activities of oats could have significant health benefits.

• Journal of Life Science
• /
• v.34 no.3
• /
• pp.191-198
• /
• 2024

To verify the nutritional value and safety of larvae fed with a soymilk residue-added food source, we compared and analyzed the nutritional components of and harmful substances in Tenebrio molitor larvae reared on wheat bran. Crude protein content based on dry weight was 1.2 times higher in the 10% soymilk residue-fed group (SR) (54.0%) than in the wheat bran-fed group (WB) (43.5%). Dietary fiber also tended to be 1.9 times more in the SR (4.9%) than the WB (2.5%). Among unsaturated fatty acids, the linoleic acid content was found to be 1.1-fold higher in the SR (32.9%) than in the WB (29.0%). Potassium, which was the most abundant among the macro minerals, was 1.1-fold more abundant in the WB (1,074.5 mg/100 g) than in the SR (1,014.0 mg/100 g). Among the micro minerals, zinc content was 1.2-fold higher in the SR (14.5 mg/100 g) than in the WB (11.9 mg/100 g). The results of the analysis of hazardous substances in the WB and SR revealed that the amount of heavy metals met the standards for heavy metals in edible insects, and food poisoning-inducing bacteria such as Escherichia coli and Salmonella spp. were not detected in all groups. These results indicate that mealworm larvae fed with 10% soymilk residue have abundant nutrients and are safe for intake. Thus, food sources with added soymilk residue has the potential to be used as feed ingredients.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.29 no.6
• /
• pp.579-585
• /
• 2009

The multifrequency eddy current testing(ECT) have been proposed various frequency mixing algorithms. In this study, we compare these approaches to frequency mixing of ECT signals from steam generator tubes; time-domain optimization, discrete cosine transform-domain optimization. Specifically, in this study, two different frequency mixing algorithms, a time-domain optimization method and a discrete cosine transform(DCT) optimization method, are investigated using the experimental signals captured from the ASME standard tube. The DCT domain optimization method is computationally fast but produces larger amount of residue.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 1998.10a
• /
• pp.521-526
• /
• 1998

This study was initiated to build runoff plots, install soil and water quality monitoring systems and collect background data from the plots and soils to assess runoff the nonpoint source pollution and soil physical change in mountainous soils. Eleven 3 $\times$ 15 m runoff plots and monitoring systems were installed at a field of National Alpine Agricultural Experiment Station to monitor soil physical change, and discharge of nonpoint source pollutant. Corn and potato were cultivated under different fertilizer, tillage and residue cover treatments. The soil has a single-layered cluster structure that has a relatively good hydrologic properties and can adsorb a large amount of nutrient. 11 runoff plots were treated and monitored with respect to physical property of the soil, runoff and sediment discharge.