• Korean Journal of Heritage: History & Science
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• v.56 no.4
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• pp.160-189
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• 2023

The Cheonjeon-ri petroglyph is inscribed with shale formation belonging to the Daegu Formation of the Gyeongsang Supergroup in the Cretaceous of the Mesozoic Era. This rock undergoes thermal alteration to become hornfels, and has a high hardness and dense texture. Rock-forming minerals have almost the same composition as quartz, alkali felspar, plagioclase, calcite, mica, chlorite and opaque minerals, but calcite is rarely detected in the weathered zone. The petroglyph forms a weathered zone with a certain depth, and there is a difference in mineral and chemical composition between weathered and unweathered zones, respectively. The CaO contents of the weathered zone were reduced by more than 90% compared to that of the unweathered zone, because calcite reacted with water and dissolved. As a result of calculating the surface weathering depth for the petroglyph with the transmission characteristics of X-rays, depth of the parts in falling off and exfoliation showed a depth of about 0.5 to 1 mm, but the weathering depth in most areas was calculated to be about 3 to 4 mm. This can be proved by the contents and changes of Ca and Sr. The surface discolorations of the petroglyph are distributed with different color density, and the yellowish brown discoloration is alternated with a thin biofilm layer, showing a coverage of 79.6%. Therefore, periodic preservation managements and preventive conservation monitoring that can effectively control the physicochemical and biological damages of the Cheonjeonri petroglyph will be necessary.

• Clean Technology
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• v.29 no.4
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• pp.297-304
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• 2023

The rapid advancement of the high-tech electronics industry has led to a significant increase in high-concentration ammonia wastewater. Various methods have been attempted to reliably treat wastewater containing high concentrations of ammonia, but no successful technology has yet been developed and applied. In this study, the removal efficiency and characteristics of ammonia nitrogen was evaluated according to changes in temperature, air loading rate, and liquid loading rate using a closed circulation countercurrent packed tower type demonstration facility for wastewater containing high concentrations of ammonia generated in the high-tech electronics industry. The temperature was varied while maintaining operating conditions of a wastewater flowrate of 20.8 m³ h^-1 and an air flow rate of 18,000 Nm³ h^-1. The results showed that at temperatures of 45,50,55, and 60℃, the removal efficiencies of ammonia nitrogen (NH₃-N) were 87.5%, 93.4%, 96.8%, and 98.7%, respectively. It was observed that temperature had the most significant impact on the removal efficiency of NH₃-N under these conditions. As the air loading rate increases, the removal rate also increases, but the increase in removal efficiency is not significant because droplets from the absorption tower flow into the stripping tower. Even if the liquid loading rate was changed by ±30%, the removal rate did not change significantly. This does not mean that the removal rate was unaffected, but was believed to be due to the relatively high air load rate. Through demonstration research, it was confirmed that ammonia stripping is a reliable technology that can stably treat high-concentration ammonia wastewater generated in the high-tech electronics industry.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.17 no.1
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• pp.76-81
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• 2024

Recently, agricultural methods are changing from experience-based agriculture to data-based agriculture. Changes in agricultural production due to the 4th Industrial Revolution are largely occurring in three areas: smart sensing and monitoring, smart analysis and planning, and smart control. In order to realize open-field smart agriculture, information on the physical and chemical properties of soil is essential. Conventional physicochemical measurements are conducted in a laboratory after collecting samples, which consumes a lot of cost, labor, and time, so they are quickly measured in the field. Measurement technology that can do this is urgently needed. In addition, a soil analysis system that can be carried and moved by the measurer and used in Korea's rice fields, fields, and facility houses is needed. To solve this problem, our goal is to develop and commercialize software that can collect soil samples and analyze the information. In this study, basic soil composition measurement was conducted using soil composition measurement sensors consisting of hardness measurement and electrode sensors. Through future research, we plan to develop a system that applies soil sampling using a CCD camera, ultrasonic sensor, and sampler. Therefore, we implemented a sensor and soil analysis UI that can measure and analyze the soil condition in real time, such as hardness measurement display using a load cell and moisture, PH, and EC measurement display using conductivity.

• Korean Journal of Organic Agriculture
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• v.32 no.1
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• pp.75-90
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• 2024

Biochar is a solid substance with a high carbon content, as it is made out of biomass pyrolyzed under the condition of limited oxygen. This product has attracted attention as an environment-friendly soil amendment because it contributes to carbon neutrally and has improvement effects on the soil environment. This study conducted an experiment to evaluate soil physiochemical properties and microbial community changes in a melon greenhouse according to the applied amount of biochar to investigate the growth characteristics and yields of melons accordingly. In soil physical properties, an increase in the applied amount of biochar resulted in a decrease in bulk density and an increase in porosity of the soil, improving air permeability. In soil chemical properties, an increase in the applied amount of biochar led to a increasing of pH, organic matter and available phosphate content. In the growth characteristics of melons, there was a growing tendency of plant height, leaf length and leaf width according to the increasing application of biochar until 10,000 kg/ha. Moreover, melon yields also increased as the amount of biochar, 13~16% higher in 10,000 kg/ha biochar application than no treatment. Compared differences among microbial communities in the soil according to the application of biochar and found that plant beneficial bacteria dominated in biochar treatments. This study demonstrated the potential of biochar as an effective soil amendment in melon greenhouse by showing improvements in soil physicochemical properties and microbial communities.

• Journal of the Korea Organic Resources Recycling Association
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• v.18 no.3
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• pp.68-76
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• 2010

In the green house, the effect of the mixed material of vermicast and humic acid on the growth of young raddish was investigated. 5, 10, 15, 30 or 50 kg(a.i.) of solid type humic acid was mixed with 300kg(d.w.) of vermicast/10a, each of which was applicated to the soil. And the conventional treatment(600kg of conventional organic fertilizer/10a) and untreatment plot were rendered for comparison. In all the experimental plots treated with vermicast, the number of leaves, leaf length, leaf biomass, root length, root diameter, root biomass of young raddish were higher than those in untreated plot. And in the experimental plots treated with the mixed materials of vermicast and humic acid, growth rate of young raddish was equal to or higher than that in the conventionally treated plot. Fresh biomass of leaves per leol' raddish in the plot treated with 300kg of vermicast + 5kg of humic acid was 1.79 times higher than that in the untreated plot and fresh biomass of root was 2.08 times higher, which was much more effective in its growth rate than that in any other treated plots. There were no prominent changes in soil physicochemical properties after the leol' raddish harvest from the soil treated with vermicast and humic acid, though.

• Food Science and Preservation
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• v.16 no.6
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• pp.977-984
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• 2009

Campbell Early grapes, the major grape variety in Korea, contain 13 - 15% (w/v) sugar, which is lower than that appropriate for fermentation of red wine. Therefore, chaptalization with sucrose is usually used to increase the sugar level to an extent adequate to produce a wine containing about 12% (v/v) alcohol. In the present study, fermentation of freeze-concentrated Campbell Early grape juice at $25^{\circ}Brix$ was investigated using several industrial wine yeasts including Saccharomyces cerevisiae OC2, S. cerevisiae Fermivin, and S. cerevisiae W-3. During fermentation, changes in the levels of soluble solids, alcohol, total acid, and yeast viable counts were investigated. Alcohol content reached maximal levels after 9 days of fermentation, and was 12.6% (v/v) when the Fermivin strain was used and 13% (v/v) when each of the OC2 and W-3 strains was used. No significant between-strain difference was found, except for slightly slower alcohol production and sugar consumption, and a higher total acid content when strain OC2 was used. Changes in the yeast viable counts were similar during fermentation. The physicochemical characteristics of Campbell Early wine prepared using freeze-concentrated juice were investigated by measuring the levels of total phenolic compounds, organic acids, acetaldehyde, and minor alcohols and assessment of color values. Similar levels of soluble solids and total phenolic contents were observed in wines fermented by the three different strains, but a higher level of total acid was noted in OC2-fermented wine and a lower level of alcohol in Fermivin-fermented wine. The highest level of malic acid and the lowest level of lactic acid were detected in Fermivin-fermented wine. Although the wines showed variable levels of acetaldehyde and minor alcohols, the concentrations of these materials were much lower than those mandated by legal regulations promulgated by the Korean National Tax Service. Red and violet colors in OC2-fermented wine were darker than those of W-3-fermented wine. In sensory evaluation, W-3-fermented wine obtained the highest scores for color and flavor. However, the best taste score was reported for the OC2-fermented wine, whereas Fermivin-fermented wine was awarded the highest score in overall acceptance.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.5
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• pp.1457-1469
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• 2015

This study was undertaken to investigate the quality changes of salted-fermented anchovy meat made by varying the amount of salt during fermentation at $15^{\circ}C$. Anchovy (11.0-14.0 cm of length, 10.7-17.5 g of weight) added with 15-25% of salt was filled in a round form plastic container (i.d. $10.5{\times}11cm$), and then fermented at $15^{\circ}C$ for 110 days. The factors such as proximate composition, pH, color value (L, a, b), TBA value, amino-N content, salinity, hardness value, free amino acid content and sensory evaluation of salted-fermented anchovy meat were measured. Ash content, color value (redness), TBA value, amino-N content. salinity and hardness value of salted-fermented anchovy meat were increased, but color value (lightness), and moisture content were decreased during fermentation at $15^{\circ}C$. A salted-fermented anchovy meat added with 15% of salt was shown higher content of moisture, amino-N content and free amino acid, TBA value than those of 20 or 25% of salt. Ash content, salinity and hardness value were highest in a product added with 25% of salt. From the result of sensory evaluation, Addition amount of 15% salt and fermentation periods of 110 days were determined to be the most desirable palatability of salted-fermented anchovy meat.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.2
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• pp.269-276
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• 2016

This study was conducted to determine the inactivation effects of slightly acidic electrolyzed water (SAEW) on microorganisms attached to salted Chinese cabbage and food materials of kimchi, such as slice radish and green onion. In addition, changes in microbial and physicochemical quality of manufactured kimchi during storage at $4^{\circ}C$ for 4 weeks were investigated. Compared to the untreated control with tap water, total bacterial counts (TBC) of Chinese cabbage, slice radish, and green onion were reduced by 1.75, 1.68, and 1.03 log CFU/g at dipping times of 20 min, 5 min, and 10 min, respectively, upon treatment with 30 ppm SAEW at $40^{\circ}C$. Effect of microbial inhibition was higher in salted Chinese cabbage brined in 10% salt (w/v) of 30 pm SAEW at $40^{\circ}C$ than in untreated control with tap water, as indicated by 1.00 log CFU/g reduction. TBC of kimchi manufactured with materials treated with 30 ppm SAEW at $40^{\circ}C$ was not significantly affected compared to untreated control, although coliforms were remarkably reduced compared to the untreated control. At the beginning of storage (1 weeks), TBC and lactic acid bacteria (LAB) counts increased by approximately 9 and 7.66~8.18 log CFU/g, respectively, and coliforms were completely eliminated. The pH and acidity of kimchi at 2 weeks were 4.34~4.49 and 0.55~0.66%, respectively, and then slowly decreased. The texture (firmness) of kimchi decreased with storage time, but the difference was not significant. This combined treatment might be considered as a potentially beneficial sanitizing method for improving the quality and safety of kimchi.

• Korean Journal of Food Science and Technology
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• v.52 no.5
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• pp.560-563
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• 2020

Cold plasma has been applied to improve quality of food product; however, studies on its effects on microbial and physicochemical qualities of rice noodles are rarely conducted. In this study, changes in the quality characteristics of rice noodles treated by cold plasma were determined. Cold plasma was generated in a square-shaped plastic container (250 W, 15 kHz, ambient air), and dielectric barrier discharge plasma treatments were applied to rice noodle samples for 0, 10, or 20 min. Rice noodles inoculated with either Bacillus cereus or Escherichia coli O157:H7 were subjected to plasma treatment for 20 min, and the approximate bacterial count reduction were 4.10 and 2.75 log CFU/g, respectively. The Hunter color values of the sample were increased after cold plasma treatment. Peroxide values and thiobarbituric acid reactive substance (TBARS) were increased with an increase in cold plasma treatment time. Futhermore, lipid oxidation was enhanced. Although further studies are warranted to evaluate changes in chemical qualities, such as lipid oxidation of rice noodles, induced by cold plasma, the results suggest that cold plasma can improve the microbial and physical qualities of rice noodles.

• Korean Journal of Food Science and Technology
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• v.33 no.4
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• pp.444-450
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• 2001

Kochujang, fermented hot pepper paste, was treated with combined high hydrostatic pressure and heat. Viable cell counts and chemical compositions of Kochujang were determined as a function of high pressure processing conditions such as temperature, pressure and time, and during storage for 120 days at $37^{\circ}C$. Viable cell counts were decreased with the increase of temperature, pressure and time. Viable cell counts in the treated Kochujang were decreased up to $0{\sim}3$ log cycle with the temperature of $49{\sim}73^{\circ}C$, $0{\sim}3$ log cycle with the pressure of $380{\sim}680\;MPa$, and $2{\sim}5$ log cycle with the time of $10{\sim}70\;min$, compared with the untreated. pH, titratable acidity, amino nitrogen, reducing sugar and ethanol content in the treated Kochujang were comparable to the untreated regardless of the treatment condition. Hunter L, a and b values in the treated Kochujang were higher than those of the untreated. Viable cell counts were decreased with the increase of the storage period at $37^{\circ}C$. Viable cell counts in Kochujang treated at 380 MPa/30 min were decreased up to 2 log cycle from $1.8{\times}10^6\;to\;1.94{\times}10^4\;CFU/g$ after 120 days of storage, while those at 680 MPa/70 min were not detected after 60 days from the initial stage of $4.00{\times}10^1\;CFU/g$. pH, amino nitrogen and ethanol content were decreased, and titratable acidity were increased significantly as the increase of the storage period. Hunter L, a and b values also decreased significantly. The changes in physicochemical properties of Kochujang treated at 680 MPa/70 min were greater than those at 380 MPa/30 min.