• Journal of Environmental Science International
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• v.30 no.3
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• pp.245-255
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• 2021

In this study, we evaluated the effect of the type of sewage sludge (digested, non digested) on drying efficiency according to the polymer injection rate. The drying characteristics were shown using a near-infrared ray (NIR) and a microwave. As a result of the drying characteristics with NIR at a polymer dose ratio of 8%, the heating up period is up to 6 minutes after the start of the drying experiment. Afterwards, the constant rate drying period of the digested sludge (A, C and G sites) was 6 minute → 18 minute, showing a rapid decrease in moisture. On the other hand, non digested sludge (B, D, E, F, H, I, J and K sites) showed gradual drying characteristics compared to digested sludge until complete drying (10%). As the polymer dose ratio of 10% and 12%, the heating up period for digested sludge is up to 6 minute after the start of the experiment. Afterwards, the constant rate drying period of the digested sludge was 6 minute → 20 minute, showing a rapid decrease in moisture. On the other hand, the heating up period of non digested sludge was up to 10 minute after the start of the experiment, and the constant rate drying period was 10 minute → 22 minute, which was shorter than digested sludge. As a result of the drying characteristics with microwave at a polymer dose ratio of 8%, 10% and 12%, the constant rate drying period the digested sludge was 4 minute → 20~22 minute, showing a rapid decrease in moisture. On the other hand, non digested sludge of the constant rate drying period was 4 minute → 22~30 minute, which was longer than digested sludge.

• Journal of Naturopathy
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• v.9 no.2
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• pp.57-61
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• 2020

Purpose: Purpose: This study was to study the effect of foot bathing on menopausal symptoms and sleep disorders in female subjects in their 50s with menopausal symptoms. Methods: After 12 weeks of foot bath therapy three times a week, pre- and post-menopausal signs were measured. Results: Subjects with hot flashes, heart discomfort, sleep problems, depression, irritability, anxiety, physical and mental fatigue, sexual problems, urination problems, vaginal dryness, and joint and muscle discomfort significantly improved after than before(p < .001). Subjective sleep quality, sleep incubation period, sleep duration, sleep disturbance score, sleep drug use, and sleep dysfunction significantly decreased after foot bath than before(p < .001). Habitual sleep efficiency increased considerably. Conclusions: The subjects showed overall improvement in menopausal symptoms and sleeping quality after a foot-bath. Therefore, foot bath therapy is evaluated as a natural healing therapy suitable for improving menopausal symptoms and sleep.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.522-522
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• 2023

지하수 시스템의 방출은 저지대 강에서 건조기에 흐르는 하천 유지유량의 원천이 된다. 수자원 분야에서 분포형 모형이 도입되며 수문 분석의 고도화가 이루어지고 있는 오늘날에도, 아직 대수층 깊이 등 지하수관련 매개변수에 대한 연구는 미진한 실정이다. 본 연구는 분포형 모형의 지하수 관련 매개변수 중 지형자료에 해당하는 대수층 깊이의 물리적인 분포형태를 예측하고, 지하수 모의결과를 검토하여 해당 기법의 적용성을 확인하였다. 본 연구에서는 북측의 미계측 유역을 포함한 소양강 유역을 연구대상 지역으로 설정하였고, 정밀한 분포형 모형인 GSSHA(Gridded Surface Hydrologic Analysis)를 활용하였다. 대수층 깊이 추정 방법은 크게 세가지 시나리오로 구분하여 모의를 진행하였다. 유역의 지하수 데이터를 통해 도출된 대수층깊이 등분포(시나리오1), 지표 고도와 대수층 깊이의 선형 반비례 관계를 가정한 선형 회귀식(시나리오2), 동일한 가정을 두고 Log차원에서 회귀식을 적용한 경우(시나리오 3). 위 3가지 시나리오를 통해 산정된 유출량과, 지하수 수위 등을 소양강댐 유입량 자료 및 유역 내 6개 지하수 관측소를 대상으로 결과를 비교하여 적용성을 확인하였다. 시나리오별 유출량 모의 오차평가 결과, 관측 첨두 유량을 가장 잘 반영하고 있는 기법은 일반적으로 선행 연구에서 많이 활용하고 있는 등분포형 기법으로 분석되었으며, 과소·과대 모의된 정도를 나타내는 지표와 모형의 효율성을 나타내는 지표는 선형 회귀분석 기법이 가장 우수한 결과로 분석되었다. 따라서, 대수층 깊이를 등분포하여 모의하던 기존 방식에 비해 지면고도-대수층깊이 간의 반비례 관계를 적용하는 방식이 지하수 모의에 있어서 보다 합리적일 것으로 판단된다. 향후 임의의 인자와 대수층 깊이간의 정밀한 회귀관계를 도출한다면 더욱 합리적이고 신뢰성 높은 결과를 얻을 수 있을것으로 기대된다. 또한 유역 단위의 지하수 모의가 정밀하게 이루어진다면 최근 많은 관심이 집중되는 하천 유지유량과 건기 유출 등의 연구 분야에도 많은 기여를 할 수 있을 것으로 기대된다.

• Korean Journal of Food Science and Technology
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• v.54 no.1
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• pp.66-74
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• 2022

To improve the solubility of β-carotene, three types of β-carotene-loaded nanocapsules were prepared using chitosan (CS) and two cross-linkers, sodium tripolyphosphate (TPP) and hyaluronic acid (HA), alone or in combination (CS-TPP, CS-TPP-HA, and CS-HA). The entrapment efficiency of all nanocapsules significantly increased with an increase in TPP and HA, with the efficiency ranging from 95% to 99%. The solubility of β-carotene was significantly improved by CS nanoencapsulation before and after lyophilization and during storage. CS/HA nanoencapsulation significantly improved (by 11-fold) the water solubility of β-carotene. In particular, CS/HA nanoencapsulation was the most effective in terms of not only the solubility of β-carotene, but also the redispersibility ratio. Therefore, CS/HA encapsulation could be useful for improving the solubility of poorly soluble active ingredients, such as β-carotene.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1D
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• pp.57-65
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• 2008

Joint of concrete pavement contributes to improvement of pavement performance by preventing occurrence of random cracking due to drying shrinkage and temperature changes of concrete slabs at early age. However, saw-cutting operations performed prior to sufficient concrete hardening develop micro-cracking of the concrete near the joints, which may develop to long-term distresses due to repetitious traffic and environmental loadings. To reduce the distresses, the joint crack inducers with heights of 100 mm, 150 mm, and 220 mm and the joint cracking slots with various depth were installed at a test section to investigate occurrence of the joint cracks and their behaviors over 5 months. As the results, higher efficiency of the crack inducing and larger behavior of the joint cracks were observed for the taller joint crack inducer. Higher efficiency of the crack inducing and improvement of the joint performance are warranted by additional investigation and reformation of the joint crack inducer.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.218-219
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• 2022

The Korea Institute for Advancement of Technology and the Ulsan ICT Promotion Agency are building an electric smart ship using a full range of ICT with advanced technology, and are expected to demonstrate it in 2022. For the demonstration of onboard ship equipment, it needs to develop a demonstration procedure. There are 4 types of onboard equipment preferentially selected for the development of the demonstration test procedure which are an electronic chart display and information system, a ship RADAR system, a voyage data recorder, and a ship energy efficiency monitoring system. This paper describes the demonstration procedure based on the equipment standard for the electronic chart display and information system among 4 selected types of demonstration equipment, and also the verification test checklist and template is introduced.

• Microbiology and Biotechnology Letters
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• v.37 no.3
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• pp.231-237
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• 2009

This paper aimed to develop a solvent extraction and purification process to recover high-purified ${\beta}$-carotene from recombinant Escherichia coli. Cells harvested from the culture broth were treated through numerous steps: dehydration, solvent extraction, crystal formation and separation. To optimize the extracting condition, experiments were carried out to investigate the effect of cell disruption, temperature, organic solvents, solvent-biomass ratio on the yield of ${\beta}$-carotene extracted from cells. The result indicated that no significant differences of extraction yield were observed from cells with or without step of cell disruption. Among different extracting solvents, the highest extraction yield of ${\beta}$-carotene, 30.3 mg-${\beta}$-carotene/g-dry cells, was obtained with isobutyl acetate at solvent-biomass ratio 25 mL/g-dry cells at $50^{\circ}C$. Notably, in case of acetone, the extraction yield was quite low when using acetone itself, but increased almost up to the highest value when combining this solvent and olive oil. The purity of ${\beta}$-carotene crystals obtained from crystallization and separation was 89%. The purity degree was further improved up to 98.5% by treating crude crystals with additional ethanol washing.

• Microbiology and Biotechnology Letters
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• v.42 no.2
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• pp.162-169
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• 2014

In the course of study for the development of functional food using red beans (azuki beans, Phaseolus radiatus L.), the ethanol extracts from raw-red bean (RRB) and boiled-red bean (BRB) were prepared, and the components and various biological activities of both were compared. It was observed that the extraction yield, and the total polyphenol content, of the BRB were 1.2 times higher than that of the RRB. However, the contents of total flavonoid, total sugar and reducing sugar in the BRB were 30, 27.9 and 30.8% respectively when compared with those of RRB. In relation to antioxidative activity, both RRB and BRB exhibited moderate DPPH anion, ABTS cation, and nitrite scavenging activities and reducing power, though in all cases RRB demonstrated stronger activities than BRB. The extracts of RRB and BRB did not reveal any antimicrobial activities. In a ${\alpha}$-amylase inhibitory activity assay, RRB was higher than BRB, while BRB showed higher ${\alpha}$-glucosidase inhibitory activity than RRB. A strong and particular activity was observed in an anti-thrombosis activity assay of RRB. The extract of RRB demonstrated strong inhibitions against prothrombin and blood coagulation factors, with moderate thrombin inhibition. However, the extract of BRB did not exhibit any significant anti-thrombosis activity. Our results indicate that RRB has different, but useful biological activities, and loss or elimination of the biologically active substances in RRB occurs during the production of BRB. Therefore, to develop more functional foods from red beans, a study of suitable boiling, heating and drying processes is essential, and the efficient re-use of boiled waste water from the boiling process is necessary. These results could be applied to the further development of functional red bean beverages and sweat red bean pastes.

• Korean Journal of Food Science and Technology
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• v.40 no.2
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• pp.123-128
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• 2008

The MRLs (maximum residue limits) of DDT (DDD and DDE) in fresh ginseng, dried ginseng, and steamed red ginseng are set as low as 0.01 mg/kg, 0.05 mg/kg, and 0.05 mg/kg, respectively. Therefore, this study was undertaken to develop a simple and highly sensitive analysis method, as well as to reduce interfering ginseng matrix peaks, for the determination of DDT isomers (o,p'-DDE, p,p'-DDE, o,p'-DDD, p,p'-DDD, o,p'-DDT, and p,p'-DDT) in fresh ginseng, dried ginseng, and steamed red ginseng at the 0.01 mg/kg level. The method used acetonitrile extraction according to simultaneous analysis, followed by normal-phase Florisil solid-phase extraction column clean-up. The purification method entailed the following steps: (1) dissolve the concentrated sample extract in 7 mL hexane; (2) add 3 mL of $H_2SO_4$; (3) vigorously shake on avortex mixer; (4) cetrifuge at 2000 rpm for 5 min; (5) transfer 3.5 mL of the supernatant to the Florisil-SPE (500 mg/6 mL);and (6) elute the SPE column with 1.5 mL of hexane and 10 mL of ether/hexane (6:94). The determination of DDT isomers was carried out by a gas chromatography-electron capture detector (GC-${\mu}$ECD). The hexane and ether/hexane (6:94) eluate significantly removed chromatographic interferences, and the addition of 30% $H_2SO_4$ to the acetonitrile extract effectively reduced many interfering ginseng matrix peaks, to allow for the determination of the DDT isomers at the 0.01 mg/kg level. The recoveries of the 6 fortified (most at 0.01 mg/kg) DDT isomers from fresh ginseng, dried ginseng, and steamed red ginseng ranged from 87.9 to 99.6%. The MDLs (method detection limits) ranged from 0.003 to 0.009 mg/kg. Finally, the application of this method for the determination of DDT isomers is sensitive, rapid, simple, and inexpensive.

• Food Engineering Progress
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• v.14 no.2
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• pp.166-172
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• 2010

The extraction of polyphenol and flavonoid from citrus peel was performed by the ethanol, sugar, hot water (80$^{\circ}C$), and subcritical water extraction methods. The maximum yields of total polyphenolic compounds (27.25${\pm}$1.33 mg QE/g DCP, QE and DCP indicate quercetin equivalent and dried citrus peel, respectively) and flavonoids (7.31${\pm}$0.41 mg QE/g DCP) were obtained by subcritical water extraction (SWE) with operating conditions of 190$^{\circ}C$, 1300 psi, and 10 min. The yields by SWE were over 7.2-, and 8.5-fold higher than those of total polyphenols (3.79${\pm}$0.73 mg QE/g DCP) and flavonoids (0.86${\pm}$0.27 mg QE/g DCP) obtained using the ethanol extraction, which showed the highest extraction efficiency among tested conventional methods, respectively. Antioxidant activities of extracts obtained by different methods showed no significant differences. However, the relative antioxidant yield per 1 g dried citrus peel by SWE (190$^{\circ}C$, 10 min) was over 9.5-fold higher than that by the ethanol extraction.