• Journal of the Korean Applied Science and Technology
• /
• v.37 no.4
• /
• pp.1041-1051
• /
• 2020

The technology of microbubbles and nanobubbles originated in Japan and Europe is applicable to various applications and its effects are diverse, attracting attention not only from many researchers but also from industry experts. In particular, nanobubbles have the advantage that they can be applied to products in the form of liquids, such as cosmetics, from the study that they can exist for more than several months in water. In this study, it was carried out the production of nanobubbles using bubble encapsulation technique and the experiment of skin permeability enhancement of active substances in cosmetics using nanobubble techniquethree. Nanobubbles were confirmed to affect the skin permeability increase of active substances, and up to 250% increase in skin permeability compared to non-bubbles-free materials(Caffeic acid, at 8 hour). It is expected that research results and industrial ripple effects can be expected not only in the cosmetic field, but also in fields applicable to the improvement of permeability by nanobubble techniques, such as areas related to drug delivery system.

• Applied Chemistry for Engineering
• /
• v.23 no.2
• /
• pp.143-147
• /
• 2012

Since the expansion of perlite occurs in a few second in high temperature, it is difficult to identify an expansion phenomenon through experiments. In order to explain this phenomenon, a numerical study has been carried out by setting a model that water vapour diffuses to a tiny bubble existing in perlite melts and then makes the bubble grow and perlite expand. When the bubble grew and the perlite expanded due to the diffusion of water vapour, the dynamic temperature of perlite decreased. Meanwhile, the dynamic pressure of bubble increased at the beginning as water vapour diffuses in melts, but rather decreased after a rapid expansion of bubble.

• Journal of ILASS-Korea
• /
• v.25 no.1
• /
• pp.15-20
• /
• 2020

This study aims to investigate injection rate and microscopic spray characteristics of diesel fuel containing fine air bubble (FBD). fine bubble was generated by cavitation theory using bubble generator. Fuel spray was injected into constant volume chamber and visualized by high speed camera. The injection rate data was acquired with bosch tube method. Injection rate of finebubble diesel was very similar with that of diesel. It showed slightly faster injection start by 5 ㎲ attributed to the low viscosity characteristics. In microscopic spray visualization, fine bubble diesel spray showed unsymmetric spray shape compared with diesel spray. It also showed very vigorous spray atomization performance during initial spray development. Improved atomization was also attributed to the low viscosity and surface tension of finebubble diesel fuel.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2017.04a
• /
• pp.133-133
• /
• 2017

최근 딸기 생산이 확대 되면서, 고품질 다수확이 가능한 딸기 우량묘에 대한 수요가 빠르게 늘고 있으며, 딸기 육묘에 관한 관심이 더욱 늘고 있다. 그러나, 육묘시 작물에 따른 포트 혹은 트레이 선정에 대한 연구는 거의 이루어지지 않고 있다. 또한, 마이크로버블의 세정 능력은 이미 산업현장에서 널리 알려져 있으나 이를 이용한 시스템 개발은 농업분야에서는 미비한 실정이다. 따라서, 딸기 육묘에 적합한 마이크로버블 시스템을 설계하여 실증 개발함으로써 딸기 육묘 농가의 자립능력을 제고하고, 딸기 육묘 생산시스템의 확대 하여 농가소득 증대에 기여하고자 한다. 실험방법은 생육에 적합한 육묘용 트레이를 선정하고, 마이크로 버블 시스템을 적용한 육묘와 기존 방법에 의한 육묘의 비교 실험하였다. 포트의 용량에 따른 뿌린 근부의 성장변화를 관찰하고, SEM 촬영을 통하여 딸기 뿌리근부의 조직의 치밀성을 확인하였다. 기존 저면관수의 경우 딸기탄저병 확산을 억제하지만, 반입에 의한 감염주의 발병을 억제하는 것은 아니다. 따라서 포트 및 트레이를 청결하게 관리할 필요가 있으며 이를 해결하기 위해 미세기포(micro-bubble)를 사용한 클리닝이 상당한 효과가 있는 것으로 확인하였다. 또한 조직의 치밀도을 측정하기 위해 딸기 육묘 조직을 SEM 촬영하여 분석하였으며, 미세기포를 이용한 딸기 육묘 방법이 기존의 딸기 육묘 방법에 비하여 조직이 치밀한 것으로 확인 되었다. 또한 배지량 및 육묘 트레이가 딸기 육묘의 성장에 영향을 미치며 제1액아가 １개밖에 발생하지 않는 포기가 많아지고 '눈 없는 포기'의 발생 현상들이 발생하고 있어 적정 육묘 트레이의 선택 및 배지량 조절하는 비교 실험을 통하여 해결하였다. 본 연구의 결과 개선된 육묘트레이를 사용함으로써 제1액아의 형성이 촉진되어 정과방 후의 제1액과 방의 수확량이 증대한다는 것에 의해서 １월 혹은 ２월부터의 수량이 증대되어 소득향상이 기대되며, 마이크로버블을 저면관수에 적용함으로써 트레이의 청결을 유지하여 병해를 예방하고 딸기모종의 조직을 치밀하게 함으로써 딸기의 우량육묘를 얻는데 기여 할 것으로 기대된다.

• Clean Technology
• /
• v.26 no.1
• /
• pp.13-21
• /
• 2020

Air pollutants in a subway are complexly caused by outdoor factors such as ventilating opening and indoor factors such as the movement of passengers on the subway. According to recent research results, most of the air pollutants generated in subway tunnels and stations are caused by indoor variables such as train movement. To control air pollutants such as particulate matter (PM), a prevention facility such as the electrostatic precipitator (EP) or bag filter collector was required in a subway station. In particular, the PM removed by the EP must be kept clean continuously to manage PM effectively. Therefore, a nano-bubbling washing system was developed in this study to clean a contaminated collecting plate in an EP at the main subway tunnel in Seoul. Removal efficiency compared with normal water and nano-bubbling water was likewise studied. As a result, the washing efficiency of collective PM increased in accordance with the increasing of injection pressure, with nano bubbling washing being 130.8% higher than tap water. According to increase in washing times, the maximum washing efficiency was 143.1% higher than tap water, but suitable washing times were less than 3 times. According to the results of the washing efficiency by variation of residence time, it was confirmed that the maximum residence time of nano-bubble water was maintained within 5 minutes.

• The Journal of the Korea Contents Association
• /
• v.19 no.6
• /
• pp.249-256
• /
• 2019

Lueco-crystal violet(LCV) is a very effective reagent used to enhance bloodstain. However, when the LCV is treated to the bloody fingerprint, the bubbling occurs, so that the minutiae and features of the fingerprint can be damaged. In this study, we studied a method to reduce the bubbling of LCV. As a result, the most effective method for reduction bubbling and enhancement bloodstain was to treat ethanol-based aminotriazole(AT) solution before LCV treatment.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.36 no.12
• /
• pp.1643-1651
• /
• 2012

Recently, with increasing standards of living and income, environmental pollution has attracted increased interest. On account of a revision to water pollution regulations, the improvement of sewage disposal efficiency was studied. One of the ways to improve the sewage disposal efficiency is to increase the dissolved oxygen content of water in the water treatment tank. In this study, we suggest a nozzle design using a spiral and a crash mode for generating micro bubbles and thus increasing the dissolved oxygen content of water. The micro bubbles through the spiral and crash flows are generated in the nozzle. In the design of the crash mode, the development goal with regard to the bubble size was not achieved. On the other hand, a bubble size of $0-50{\mu}m$ accounted for 79.3% of all bubbles in the spiral mode. This study should contribute toward increasing the sewage disposal efficiency.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.40 no.6
• /
• pp.912-917
• /
• 2011

The sterilization efficacies of various washing solutions on the surfaces of vegetables such as sesame leaves, lettuce, and mini-cabbage were investigated. The washing solutions were tap water (TW), microbubble water (MB), electrolyzed water (EW), and microbubble electrolyzed water (MB＋EW). After Escherichia coli and Bacillus cereus were artificially inoculated onto the surfaces of vegetables, each vegetable was washed for 1, 3, and 5 min with TW, MB, EW 100 (100 mg/L of available chlorine), EW 200 (200 mg/L of available chlorine), MB+EW 100, and MB＋EW 200. The washing efficacy of MB was slightly higher than that of TW, and EW was more effective than MB (p<0.05). In all instances, the sterilization efficacies of MB+EW 100 and MB+EW 200 were higher than those of EW 100 and EW 200 (p<0.05). Thus, MB+EW offers an effective means of reducing the studied microorganisms in a short time period. The MB＋EW washing method provides microbial reduction on the surfaces of various vegetables and enhances the microbiological safety of the vegetables.

• Transactions of the Korean hydrogen and new energy society
• /
• v.27 no.1
• /
• pp.121-126
• /
• 2016

Hydraulic performance of a micro-bubble pump has been analyzed by numerical simulation and experimental measurements. Flow recirculation apparatus between the pump inlet and outlet reserviors has been adopted to measure pump performance according to flow conditions sequentially. To analyze three-dimensional flow field in the micro-bubble pump, general analysis code, CFX, is employed. SST turbulence model is employed to estimate the eddy viscosity and compared the pump performance to k-${\varepsilon}$ model. Unstructured grids are used to represent a composite grid system including blade, casing and inlet casing. It is found that the numerical model used in the present study is effective to evaluate the pump performance. From the numerical simulation, low velocity region due to pressure loss is decreased where pump efficiency has maximum value. Detailed flow field inside the micro-bubble pump is also analyzed and compared.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.122-122
• /
• 2014

수중방전을 환경분야에 적용하기 위한 플라즈마 부상법이 개발되었다. 플라즈마 부상법은 물 속에서 발생시킨 플라즈마가 가지고 있는 주요특성 중 물리적 특징인 쇼크웨이브, UV조사, 버블생성 등과 화학적 특징인 OH라디칼 및 염소산화물 생성 등을 이용하여 물 속에 존재하는 용존성 및 입자성 물질을 부상분리 기법으로 제거하는 공법이다. 유기물을 제거하는 기작으로는 침전, 여과, 분해 등이 있고, 이를 구현하기 위한 공정으로 중력침강법, 부상분리법, 멤브레인법, 미생물법 등이 있다. 이 중에서 가압공기부상법은 침강법에 비해 부지면적을 적게 소모하고 처리시간이 50% 이상 감소되는 특징이 있다. 가압공기부상법은 물 속에 공기를 과포화시킨 후 노즐을 통해 재분사할 때 발생하는 압력차에 의해 미세기포가 발생함을 이용하여 유기물을 분리하는 공법이다. 그러나, 가압용 장비 및 반송수가 필요하고, 미생물분리는 불가능한 단점이 있다. 이에 본 연구에서는 미생물살균과 유기물 분리가 동시에 일어나는 플라즈마를 이용한 부상분리기법을 개발하였다. 본 연구에서는 난분해성 용존유기물인 휴믹산 100 mg/L의 플라즈마 공기부상법에 의한 제거능을 확인하였다. 용존성 휴믹산을 입자성 물질로 전환하여 플록을 형성시키고자 알루미늄설페이트(Al2(SO4) $3{\cdot}18H2O$)를 100 mg/L 주입하였고, 침출수와 같이 염도가 높은 물을 모사하고자 35 g/L의 염화나트륨을 첨가한 상태에서 방전을 실시하였다. 방전에 사용된 전원은 EESYS사에서 제작한 펄스형 고전압 전원장치를 사용하였고 최대 15 kW의 출력 중 6 kW의 전력을 인가하였다. 전극 한 개는 2 mm 텅스텐봉을 세라믹튜브로 감싼 구조로 총 사용전극은 28개이다. 전극 한 개당 대략 200 Watt의 전력이 소모되며 이 때 최대의 버블이 생성됨을 확인하였다. 전극 1개에서 생성되는 버블의 부피는 14 mL/min 로 측정되었다. 버블의 크기는 평균 70 um이고 가압공기부상법에서 최적공기크기로 제시하고 있는 40~80 um 의 버블은 약 80% 가량 생성된다. 본 연구에서 사용된 반응시스템에서의 물의 높이는 약 500 mm 이고 전체 40 L의 수조가 3개의 벽으로 분리되어 4개의 수조로 분리되었다. 각 수조는 하부에 7개의 전극을 포함하고 있다. 플라즈마 발생시 생성되는 기포는 약 1분 방전 후에 포화농도에 도달하며 방전종료 후 약 4분간 수체 내에 남아있게 된다. 이를 공정에 적용하여 1분 방전 및 4분 휴지의 순서로 플라즈마를 인가하였다. 휴믹산 용액의 유량을 2 lpm 으로 운전하였을 때 최종 처리율은 94% 이고 이때의 대장균 살균능은 99%이다.