• Korean Chemical Engineering Research
• /
• v.59 no.3
• /
• pp.399-409
• /
• 2021

In order to utilize dolomite as a calcium/magnesium compound material, it was prepared highly reactive calcined dolomite(CaO·MgO) using a microwave kiln (950 ℃, 60 min). The experiment was performed according to the standard of the hydration test (ASTM C 110) and hydration reactivity was analyzed as medium reactivity (max 74.1 ℃, 5 min). Experiments were performed with calcined dolomite and salt (MgCl₂·6H₂O) (a) 1:1, (b) 1:1.5, and (c) 1:2 wt% based on the hydration reaction of calcined dolomite. The result of X-ray diffraction analysis confirmed that MgO of calcined dolomite increased to Mg(OH)₂ as the salt addition ratio increased. After the separating reaction, calcium was stirred at 80 ℃, 24 hr that produced CaCl₂ of white crystal. XRD results, it was confirmed calcium chloride hydrate (CaCl₂·(H₂O)x) and CaO of calcined dolomite and salt additional reaction was separated into CaCl₂. And it was synthesized with Ca(OH)₂ 99 wt% by NaOH adding reaction to the CaCl₂ solution, and the synthesized Ca(OH)₂ was manufactured CaO through the heat treatment process. In order to prepare calcium carbonate, CaCO₃ was synthesized by adding Na₂CO₃ to CaCl₂ solution, and the shape was analyzed in cubic form with a purity of 99 wt%.

• Korean Journal of Environment and Ecology
• /
• v.35 no.6
• /
• pp.621-631
• /
• 2021

The purpose of this study is to survey and analyze acorn production and characteristics of the Quercus acuta Thunb. according to the need for information on seed supply and seedling cultivation during the restoration of warm broad-leaved forests. For the survey, a total of 30 seed traps with a surface area of 1 m² were set up, 3 in each of 10 quadrats (8 in Wando, 1 in Haenam, and 1 in Jindo). The acorns that fell in the seed trap at the end of each month were collected from August to December each year between 2013 to 2016. The collected acorns were then classified into sound, damaged, decayed, or empty grade, and the number of acorns produced was calculated. In the case of sound acorns, acorn traits, such as length, diameter and weight of acorns without cupule, were measured. Duncan's multiple tests of acorn production and characteristics were conducted for comparative analysis of the annual average values with the values by year, stand, month, and treatment plot. The annual number of acorn dropped into the seed traps in each quadrat from 2013 to 2016 was 5-350 acorns/3 m² in 2013, 17-551 acorns/3 m² in 2014, 5-454 acorns/3 m² in 2015, and 14-705 acorns/3 m² in 2016. There was a large difference in acorn production between the quadrats, presumably attributed to the difference in the amount of light received due to the density of trees in the square. Annual acorn production per area was 335,000 acorns/ha in 2013, 932,000 acorns/ha in 2014, 556,000 acorns/ha in 2015, and 1,037,000 acorns/ha in 2016. That was a sharp variation of acorn production in the two-year cycle. As the fluctuation in the production of Q. acuta showed simultaneity between stands, it is judged that Quercus acuta Thunb. had a clear cycle of fruitfulness and fruitiness between forest objects. September showed the biggest amount of fallen acorns and largest damage from insect pests, indicating that preventing early fall of acorns could increase the fruiting period and enable mass production of sound acorns. There was no significant difference between annual average acorn length in each region. In the case of the acorn diameter and weight, the average values of acorns from Haenam were significantly higher than those from Wando and Jindo. There was no significant difference in the average annual acorn characteristics by month, and the average annual acorn length, diameter, and weight in November were 19.72mm, 12.23mm, and 1.64g, respectively, the highest between August and November.

• Journal of the Korean GEO-environmental Society
• /
• v.23 no.9
• /
• pp.33-40
• /
• 2022

Sedimentation and pH neutralization has been investigated as preteatment of acid contaminate water. The settling and neutralizing process derive more effective degradation efficiency as the pre-treatment process before the removal process of adsorption, volatile, biodegradation, or oxidation. Settling velocity, uniformity coefficient, coefficient of curvature, and grain size index can define in the sedimentation process for characteristics of the soil. The stainless steel sieve has been used to separate each particle size of the dry soil by assembling in order of 4, 10, 20, 40, 80, 100, and 200 mesh sizes. The soil from Gamcheon Port in Busan drops upper side of the sieve and shakes back and forth to separate each different size of the particle. The 1L of Imhoff cone and 200 mL of the mass cylinder were used as settling tanks to calculate settling velocity. Stokes' equation was used to figure out the average density of dry soil with a value from settling velocity. In the results, the average particle density and lowest settling velocity were 1.93 g/cm³ and 0.11 cm/s, respectively. These values can detect the range of settling points of sediment to prevent chemical accidents. In pH neutralization, the initial pH of 2, 3, 4, and 5 of nitric acid and sulfuric acid are used as an acid solution; 0.1, 0.01, and 0.001 M of sodium hydroxide and calcium hydroxide are used as a base solution. The main goal of this experiment is to figure out the volume percentage of the acid solution becomes pH 7. The concentration of 0.001 M of base solution exceeds all the conditions, 0.01 M exceeds partially, and 0.1 M does not exceed 5 v/v% except pH 2. Calcium hydroxide present less volume than sodium hydroxide at pH neutralization both sulfuric and nitric acid.

• Journal of Bio-Environment Control
• /
• v.31 no.2
• /
• pp.133-141
• /
• 2022

Bulbophyllum auricomum Lindl. is a rare orchid and has flowers with an attractive fragrance. The present study investigated the tissue culture method for micropropagation. Capsules derived from artificial self-pollination were obtained for the best seed germination in MS basal medium. Plant growth regulators (1.0 mg·L^-1 of BAP and 2.0 mg·L^-1 of NAA) were affected by callus induction from subcultured pseudobulb explants. For the callus subculture, different natural plant extracts were tested in 11 treatment media. Among them, MS medium with 150 mL·L^-1 of coconut water was generally effective in fresh weight (1.75 ± 0.08) and (3.01 ± 0.20) of callus proliferation and PLBs induction at 1 and 2 months, respectively, followed by an MS combination of 30 g·L^-1 of banana and 20 g·L^-1 of potato extract. The results of a comparative study of different MS mediums containing plant growth regulators with a natural extract combination and MS medium supplemented with natural extract only showed that MS medium supplemented with a combination of natural extracts (150 mL·L^-1 of coconut water) and plant growth regulators (2.0 mg·L^-1 of BAP and 1.0 mg·L^-1 of NAA) obtained the highest shoot regeneration (3.37 ± 0.17) and (6.41 ± 0.68) after 1 month and 2 months of culturing, respectively.

• The Korea Journal of Herbology
• /
• v.37 no.5
• /
• pp.89-96
• /
• 2022

Objectives : This research was performed to analyze the components in the different parts of Lythrum salicaria L. and to compare which parts of L. salicaria L. are appropriate for food development. Methods : L. salicaria L. was extracted in 20% EtOH at 100 ℃ for 4 hours. Cytotoxicity was investigated in 3T3-L1 cells after treatment of 10-500 ㎍/ml L. salicaria L. for 24 hours. Total polyphenol content (TPC) was estimated using 1 N Folin-ciocateu reagent. 2,2-Diphenyl-1-picryhydrazyl (DPPH) radical scavenging activity was estimated using DPPH reagent and gallic acid. The chemical composition was analyzed by high-performance liquid chromatography (HPLC). 1) Results : The half maximal inhibitory concentration (IC50) in the extracts of the whole plant, aerial parts, and root parts was 350 ㎍/ml, over 500 ㎍/ml, and 150 ㎍/ml, respectively. The TPC in the extracts of the whole plant, aerial parts, and root parts was 527.1 mg/g, 422.6 mg/g, and 781.1 mg/g, respectively. The averages of vitexin contents in the aerial parts, and root parts were 256.7 ± 154.9 ㎍/g and 266.1 ± 63.2 ㎍/g, respectively. The averages of TPC in the leaves, roots, flower stalks and stems were 224.0 ± 53.7 tannin acid (TA) mg/g, 221.8 ± 70.2 TA mg/g, 249.8 ± 34.4 TA mg/g, and 67.7±8.9 TA mg/g, respectively. The averages of DPPH radical scavenging activity in the leaves, roots, flower stalks, and stems were 282.01 ± 43.3 gallic acid equivalent (GAE) 𝜇mole/g, 260.16 ± 44.1 GAE 𝜇mole/g, 288.0 ± 9.3 GAE 𝜇mole/g, and 97.6 ± 10.7 GAE 𝜇mole/g, respectively. Conclusions : There were no significant differences in the content of components or antioxidant activity in the aerial parts compared to those in the whole plant of L. salicaria L. Furthermore, the root parts had low extract yield, cytotoxicity, and quality control problems, therefore our results suggest that the use of the aerial part of L. salicaria L. would be the most appropriate for food development.

• Resources Recycling
• /
• v.31 no.5
• /
• pp.67-76
• /
• 2022

The furniture industry has a high possibility to create value-added and a high potential to create new occupations due to the characteristics of the industry, which mainly consists of small and medium-sized enterprises (SMEs). However, the used furniture, which has sufficient reuse value, is also crushed and used as solid refuse fuel (SRF) recently. Besides, the number of waste treatment companies continues to decrease, and it occurs congestion of wood waste. As a way to solve the issue, a business model development of remanufacturing used furniture can be suggested as an alternative due to its high circular economic efficiency. Remanufacturing business including furniture industry creates positive effects in various aspects such as economic, environmental and job creation. In other words, remanufacturing is an effective recycling way to reduce input resources and energy in the production process. The results of economic analysis show that the expected annual revenue from the single worker furniture remanufacturing site was 104 million won which is 3.11 times more than the average income of a single-worker household in Korea and its B/C ratio was estimated about 30 which means high business feasibility. Revenue through furniture remanufacturing also showed 320 times higher than that of SRF production from the perspective of weight. In addition, it is shown that the GHGs reduction from the furniture remanufacturing is 2.2 ton CO₂-eq. per year, which is similar to the amount of GHGs absorption effect of 937 pine trees or 622 Korean oak trees annually. Thus the results of this study demonstrate that it is important to adopt an appropriate recycling method considering the economic and environmental effects at the end-of-life stage.

• Journal of Wetlands Research
• /
• v.24 no.3
• /
• pp.204-212
• /
• 2022

The LID technique began to be applied in Korea after 2009, and LID facilities are installed and operated for rainwater management in business districts such as the Ministry of Environment, the Ministry of Land, Infrastructure and Transport, and LH Corporation, public institutions, commercial land, housing, parks, and schools. However, looking at domestic cases, the application cases and operation periods are insufficient compared to those outside the country, so appropriate design standards and measures for operation and maintenance are insufficient. In particular, LID facilities constructed using LID techniques need to maintain the environment inside LID facilities because hydrological and environmental effects are expressed by material circulation and energy flow. The LID facility is designed with the treatment capacity planned for the water circulation target, and the proper maintenance, vegetation, and soil conditions are periodically identified, and the efficiency is maintained as much as possible. In other words, the soil created in LID is a very important design element because LID facilities are expected to have effects such as water pollution reduction, flood reduction, water resource acquisition, and temperature reduction while increasing water storage and penetration capacity through water circulation construction. In order to maintain and manage the functions of LID facilities accurately, the current state of the facilities and the cycle of replacement and maintenance should be accurately known through various quantitative data such as soil contamination, snow removal effects, and vegetation criteria. This study was conducted to investigate the current status of LID facilities installed in Korea from 2009 to 2020, and analyze soil changes through the continuity and current status of LID facilities applied over the past 10 years after collecting soil samples from the soil layer. Through analysis of Saturn, organic matter, hardness, water contents, pH, electrical conductivity, and salt, some vegetation-type LID facilities more than 5 to 7 years after construction showed results corresponding to the lower grade of landscape design. Facilities below the lower level can be recognized as a point of time when maintenance is necessary in a state that may cause problems in soil permeability and vegetation growth. Accordingly, it was found that LID facilities should be managed through soil replacement and replacement.

• Journal of Bio-Environment Control
• /
• v.31 no.3
• /
• pp.180-187
• /
• 2022

In order to select suitable light in a plant factory, electric energy use efficiency and light use efficiency should be considered simultaneously to consider operating costs as well as quantitative and functional aspects. The growth characteristics, electric energy use efficiency, light use efficiency by light intensity, LED ratio, and photoperiod conditions were compared together. Light intensity is 60, 130, 230, and 320 µmol·m^-2·s^-1 treatments, and light quality is the mixing ratio of red light and blue light 8:2, 6:4, 4:6, and 2:8 treatments. Photoperiod is 9, 12, 15, and 18 hours treatments based on the daytime. In the light intensity experiment, the growth rate increased as the light intensity increased, but there was no significant difference in the light use efficiency. When comparing the leaf fresh weight per power consumption, only the 320 µmol·m^-2·s^-1 treatment group showed significantly low efficiency, and there was no significant difference in the other treatments, so 230 µmol·m^-2·s^-1, which produced the most, was the most efficient. In the light quality experiment, the ratio of red light and blue light was measured to be high at the same time as the growth rate and light use efficiency in RB 8:2, and there was no significant difference in color difference and flavonoids content, so a Red:Blue ratio of 8:2 was the most suitable condition. In the photoperiod experiment, the longer the photoperiod, the higher the growth rate. However, there was no significant difference in the growth rate over 12 hours of daytime, so 12 hours considering the light consumption efficiency was a suitable condition. Based on the above results, LED light environmental conditions for perilla growth in plant factories were light intensity, light quality, and day length of 230 µmol·m^-2·s^-1 or more, 8:2, and 12 hours or more, respectively.

• Pediatric Infection and Vaccine
• /
• v.28 no.3
• /
• pp.133-143
• /
• 2021

Purpose: This study aimed to determine the incidence of central line-associated bloodstream infection (CLABSI) in the neonatal intensive care unit (NICU), evaluate the patients' clinical characteristics, and identify the etiologic agents for guidance in prevention and treatment. Methods: A retrospective chart review study of infants classified as having CLABSI was conducted at the NICU of Seoul National University Bundang Hospital from January 2016 to December 2020. Results: Of the 45 infants, 53 had CLABSIs within a follow-up period of 18,622 catheter days. The incidence of CLABSIs was 2.85 per 1,000 catheter days. The most common catheter type was a peripherally inserted central catheter (n=47, 81%). A total of 57 pathogens were isolated, of which 57.9% (n=33) were Gram-positive bacteria, 36.8% (n=21) were Gram-negative bacteria, and 5.3% (n=3) were Candida spp. The most common pathogens were Staphylococcus aureus (n=12, 21%) and coagulase-negative staphylococci (n=12, 21%), followed by Klebsiella aerogenes (n=8, 14%). The median duration of bacteremia was 2 days, and 19 episodes showed bacteremia for 3 days or more. The mortality rate of infants within 14 days of CLABSI was 13.3% (n=6). Conclusions: This study analyzed the incidence of CLABSI and the distribution of pathogens in the NICU. Continuous monitoring of CLABSI based on active surveillance serves as guidance for empiric antibiotic use and also serves as a tool to assess the necessity for implementation of prevention strategies and their impact.

• Korean Journal of Poultry Science
• /
• v.50 no.1
• /
• pp.1-13
• /
• 2023

The study was carried out to investigate the effects of dietary combined supplementation of antioxidants as catechin and vitamin C on growth performance, meat quality, blood profiles and stress responses of broilers exposed to high temperature. For this experiment, a total of 360 21-day-old male Ross 308 broilers were used. Treatments were assigned with 6 replicates per treatment and 10 birds per replicate in a 2 × 3 factorial design with vitamin C (0, 250 mg/kg) and catechin (0, 600, 1,200 mg/kg). The heat stress environment was maintained at temperature 32±1℃ and relative humidity 60±5% for 24 hours until the end of the experiment. The supplemented antioxidants had no significant difference in weight gain, feed intake and feed conversion ratio (P>0.05). The content of total cholesterol in blood had no interaction, but decrease (P<0.01) in the supplemented catechin group. Also, the supplementation with catechin showed increase in the SOD activity of blood, and lower corticosterone and IgM levels of broilers. The contents of HSP70 and MDA in liver decrease (P<0.05) with the supplementation of antioxidants, and HSP70 showed an interaction between groups. DPPH radical scavenging ability in breast meat increased (P<0.01) in catechin, but meat quality did not show difference according to treatments. Respiratory rate decreased (P<0.05) in catechin, but no interaction with vitamin C. In conclusion, the combination of vitamin C and catechin can alleviate stress under high temperature, such as HSP70 and MDA, but further study on the optimal supplemental level is needed.