황반원공 내에 감돈된 작은 가스방울로 인한 황반원공폐쇄 실패 1예

김진현(Jin hyun Kim),이권휘(Gwon Hwi Lee),이승우(Seung Woo Lee) 대한안과학회 2016 대한안과학회지 Vol.57 No.5

Purpose: To report a case of failed sealing of full-thickness macular hole associated with an entrapped microbubble in the hole after vitrectomy, peeling of the internal limiting membrane and C3F8 (14%) gas injection. Case summary: A 69-year-old female visited our clinic for decreased visual acuity in her right eye. The best corrected visual acuity (BCVA) was 20/200 in the right eye. The fundoscopy and spectral domain optical coherence tomography (SD-OCT) showed a full-thickness macular hole. She had a history of spine surgery and, thus was unable to maintain a prone position after surgery. The patient underwent pars plana vitrectomy, peeling of the internal limiting membrane and C3F8 (14%) gas injection in a sitting position postoperatively. Three weeks postoperatively, fundoscopy showed an entrapped microbubble within the macular hole, which was not sealed as observed on SD-OCT. We thought the entrapped microbubble within the macular hole prevented closure of the hole and removed it during the repeated surgery. At 2 weeks after the microbubble removal, fundoscopy and SD-OCT in the right eye showed the closure of the macular hole and the BCVA was improved to 20/40. Conclusions: We experienced a failed sealing of full-thickness macular hole due to an entrapped microbubble within the hole after macular hole surgery and observed the closure of the macular hole after removal of the microbubble. Based on our results, early microbubble removal operation should be considered in the treatment of an entrapped microbubble within the hole. 목적: 전층 황반원공의 치료로 유리체절제술, 내경계막제거술 및 비팽창가스를 주입하였으나 수술 후 황반원공 내에 감돈된 작은 가스방울로 인해 원공폐쇄가 실패한 증례를 경험하여 이를 보고하는 바이다. 증례요약: 69세 여성이 우안 시력 저하를 주소로 내원하였다. 우안 최대교정시력은 20/200이었고, 안저검사 및 빛간섭단층촬영에서전층 황반원공이 관찰되었다. 과거력상 허리 수술로 인한 통증으로 수술 후 안면하 자세가 불가능하였다. 수술적 치료로 유리체절제술, 내경계막제거술 및 비팽창가스를 안구 내에 주입 후 앉아 있는 자세를 하였다. 수술 3주 후 안저검사에서 황반원공 내에 감돈된 작은 가스방울을 발견하였으며, 빛간섭단층촬영에서 원공의 폐쇄가 이루어지지 않은 것이 확인되었다. 감돈된 가스방울에 의한 황반원공 폐쇄의 실패로 생각하여 재수술을 통해 이를 제거하였다. 수술 2주 후 안저검사 및 빛간섭단층촬영상 황반원공이 완전히 폐쇄된 것을 확인할 수 있었으며, 우안 최대교정시력은 20/40으로 호전되었다. 결론: 저자들은 황반원공 수술 후 황반원공 내에 감돈된 작은 가스방울에 의해 원공폐쇄 실패를 경험하였고, 이를 수술적으로 제거한 후 황반원공의 폐쇄를 확인할 수 있어 빠른 수술적 처치가 필요함을 알 수 있었다.

초음파와 microbubble 처리가 무지개송어(Oncorhynchus mykiss)의 혈청성분 및 선천성 면역에 미치는 영향

김진영 ( Jin-young Kim ),박종빈 ( Jong-bin Park ),박정수 ( Jeong Su Park ),김우성 ( Woo-seoung Kim ),김학수 ( Hak Soo Kim ),권세련 ( Se Ryun Kwon ) 한국어병학회 2019 한국어병학회지 Vol.32 No.2

Rainbow trout (Oncorhynchus mykiss) were treated with ultrasonic (40kHz) and microbubble. The organic serum components, glucose were decreased compared to control at microbubble single treat­ment (M) and ultrasonic treatment (UL), but glucose concentrations in fish serum of all experimental groups analyzed in this study were also within the normal range. The organic serum components, cholesterol and total protein were no significant change by ultrasonic and microbubble treatment. There were no significant changes in the lysozyme activity on ultrasonic and microbubble treatment. Serum bactericidal activity decreased on ultrasonic single treatment (UL) compared to the control (P<0.05), but the numbers of bacterial colonies were significantly lower than those in the negative (PBS). The results of this study indicate that ultrasonic and microbubble treatment did not have a critical effect on the serum composition and innate immunity of O. mykiss, and that it is a way to do not significant stress on the fish body as a countermeasure against sea lice.

Nek5000 기반의 마이크로 버블 유동저항감소 직접수치모사

김병천(Byeong-Cheon Kim),장경식(Kyoungsik Chang),이상욱(Sang-Wook Lee) 한국전산유체공학회 2021 한국전산유체공학회지 Vol.26 No.4

The microbubble generation technology in underwater vehicle is considered as one of the promising technique to reduce skin friction resistance. In the present work, microbubble dynamics were investigated in two-way coupled microbubble-laden turbulent channel flows with Nek5000 code based on the spectral element method. The Euler-Lagrange approach was adopted to predict the microbubble dynamics and to investigate the effect on flow field. The fully elastic collision model was implemented to consider the effect of wall-bubble interaction. To investigate the drag reduction effect of microbubble, turbulent flow in the channel at Re<SUB>τ</SUB>=135 was conducted with direct numerical simulation and a Lagrangian particle tracking approach. Three cases with different conditions in the bubble diameter and void fraction were considered.

분뇨처리를 위한 MBR공정에서 Microbubble의 적용

임지영(Ji Young Lim),김진한(Jin Han Kim) 유기성자원학회 2017 유기물자원화 Vol.25 No.1

본 연구에서는 고농도 유기성 폐수인 분뇨 처리를 위한 MBR 공정에 마이크로버블을 적용하여 처리효율을 검토하고, 안정적 운영의 가능성을 평가하고자 하였다. 연구결과, 마이크로버블을 분리막이 침지되어 있는 호기조에 직접 공급하였을 때에는 과도하게 스컴이 발생하여 처리공정의 안정적 운영이 불가능하였다. 생물반응조 전단에 마이크로버블을 공급하는 전처리조를 설치하여 고액분리와 유기물 산화를 실시한 다음 MBR 공정으로 처리한 결과 전처리조에서의 SS 제거율은 2kg, 4kg, 6kg, 그리고 8 kg CODCr/㎥ㆍday의 유기물 부하에서 각각 평균 74.3%, 82.8%, 75.0%, 52.1%를 나타내었으며, 전체 처리공정 처리수의 SS 제거율은 평균 99.4% 이상이었다. 또한 최종처리수의 TCODCr 제거율은 평균 94.0% 이상이었으며, SCODCr 제거율은 평균 74.1% 이상이었다. 한편, 마이크로버블을 호기조에 직접 공급할 경우 마이크로버블과 오염물질들이 함께 분리막에 부착되어 fouling 현상이 가속되는 현상을 확인할 수 있었다. 따라서, 분뇨와 같은 고농도 유기성 폐수 처리공정에는 SS 제거와 유기물 산화를 목적으로 생물반응조 전단에 마이크로버블을 적용함으로써 안정적인 처리가 가능함을 확인 할 수 있었다. In this study, the microbubbles were applied to the MBR process for night soil treatment, and the removal efficiency was estimated. As a result of the this study, when the microbubble was supplied directly to the aerobic tank in which the membrane was submerged, excessive scum was generated so could not stable operation of the process. The SS removal efficiencies in the pre-treatment tank were 74.3%, 82.8%, 75.0%, 52.1% on average at the 2 kg, 4 kg, 6 kg, and 8 kg CODCr/㎥, respectively. The mean removal efficiencies were more than 99.4%, 94.0%, 74.1% for SS, TCODCr, SCODCr by MBR process. On the other hand, when the microbubble are directly supplied to the aerobic tank, the microbubble and the scum are attached each other to accelerate the fouling. Therefore, it can be confirmed that stable treatment can be achieved by applying microbubble to the front of the bioreactor for removal of SS and oxidation of organic matters in high concentration organic wastewater treatment such as night soil.

벤튜리 노즐 제원에 따른 마이크로버블 발생 특성 평가

임지영(Lim, Jiyoung),김현식(Kim, Hyun-Sik),박수영(Park, Su-Young),김진한(Kim, Jin-Han) 한국산학기술학회 2015 한국산학기술학회논문지 Vol.16 No.9

본 연구는 lab-scale로 제작된 가압식 마이크로버블 발생장치의 버블크기 분포를 분석하여 장치의 최적 운전조건을 검토하고 벤튜리 노즐 제원에 따른 마이크로버블 발생 특성을 확인하였다. 실험결과, 실험실 규모의 가압식 마이크로버블 발생장치의 운전조건은 공기 주입율 0.3 LPM, 가압탱크압력 3 bar, 벤튜리 노즐을 수조와 직접 연결 하였을 때, 상대적으로 우수한 성능을 나타내었다. 벤튜리 노즐 제원을 달리한 마이크로버블 발생 특성에서는 노즐의 제원에 따른 버블크기 분포에 미치는 영향은 낮지만, 버블 발생의 성능적 측면에서는 노즐의 목 직경이 3-4 mm 일 때, D50이 54.98– 61.19 ㎛(D3L15, D4L15), 50 ㎛이하의 버블 분율은 각각 0.326, 0.345(D3L15, D4L15)로 상대적으로 우수함을 확인하였으며, 노즐 목 길이의 경우 목 길이가 20 mm인 노즐의 D50이 49.40–54.98㎛, 50 ㎛이하의 버블 분율은 0.447로서, 마이크로버블을 비교적 안정적 으로 발생시키는 것을 확인 할 수 있었다. This research was performed to review operating parameters, optimum condition and check characteristic of microbubble generation for using bubble size distribution according to venturi specification. Optimum operating condition have airflow rate 0.3 LPM, 3 bar(pressure tank) and connecting nozzle directly(without valve), it is advantageous to generate microbubble. In case of characteristic of microbubble generation according to venturi specification, effect that nozzle specification affects bubble size distribution is low impact. But considering performance aspects, when using nozzle that throat diameter 3-4 mm, D50 are 54.98– 61.19 ㎛(D3L15, D4L15), fraction of bubble less than 50 ㎛ are 0.326, 0.345. And it is superior to others. Besides, D50 and fraction of bubble less than 50 ㎛ of throat length 20 mm are 49.40–54.98 ㎛, 0.447, respectively And nozzle that throat length 20 mm is relatively tendency to generate microbubble stably.

단일반응기에서 마이크로버블-산소를 이용한 가축분뇨의 유기오염물질, 질소 및 인의 동시 제거

장재경,진유정,강석원,김태영,백이,성제훈,김영화 대한환경공학회 2017 대한환경공학회지 Vol.39 No.11

마이크로버블-산소를 이용한 물리․화학적인 방법에 의해 가축분뇨에 포함된 유기오염물질과 질소, 인 제거에 효과를 실험실 규모의 단일 반응기를 이용하여 알아보았다. 사용한 가축분뇨의 성상은 TCOD 36,894 ± 5,024 mg/L, SCOD 22,031 ± 2,018 mg/L, 암모니아성질소 4,150 ± 35 mg/L, 그리고 인산염인 659 ± 113 mg/L로 고농도의 유기오염물질과 영양염류를 포함하였다. 마이크로버블과 함께 사용한 기체로 공기를 사용하였을 때 보다 산소를 사용하였을 때, 그리고 산소의 공급량이 많았을 때 유기오염물질, 질소, 인 제거량이 증가하였다. 산소를 분당 600 mL 사용하였을 때 공기를 사용했을 때와 비교하면 TCOD 제거율은 2.5배, 인은 약 5.6배 높았다. 또한 반응 시간이 길수록 영양염류의 제거율은 점진적으로 증가하여, 암모니아성질소와인 제거는 각각 41.03 ± 0.20%와 65.49 ± 1.39%까지 제거되었다. 인 제거율을 증가시키기 위해 마이크로버블 적용 한 후 유출수를 응집침전을 시켰을 때, 인은 유입된 인 농도 대비 최대 92.7%까지 제거되는 것이 확인되었다. 그러나 유기오염물질(TCOD) 제거는 초기 6시간 이내에 28.7 ± 0.2%까지 제거되었으나 더 이상 제거되지 않았다. 이 연구 결과 마이크로버블-산소를 가축분뇨 뿐만 아니라 다양한 하․폐수처리장의 포기조에 적용하면 연계된 단위 공정에 부하를 줄일 수 있으며 또한 고품위의안정적인 유출수를 생산할 수 있는 방법으로 제시할 수 있을 것으로 판단된다. The effects of microbubble-oxygen physicochemical method for the removal of organic pollutants, nitrogen, and phosphorus contained in animal manure were investigated using a laboratory scale single reactor. The characteristics of used livestock manure were 36,894 ± 5,024 mg TCOD/L, 22,031 ± 2,018 mg SCOD/L, 4,150 ± 35 mg NH4-N/L, and 659 ± 113 mg PO4-P/L. It was confirmed that the amount of organic pollutants, nitrogen, and phosphorus removal was increased by the use of oxygen rather than air as the gas supplied with the microbubble, and by input of larger oxygen amount. When the oxygen was fed with 600 mL flow rate per minute, TCOD and phosphorus removal were 2.5 times and 5.6 times higher than those of air supplied. As the microbubble-oxygen reaction time was longer, the removal rate of nutrients increased gradually. The removal rates of ammonium and phosphorus reach to 41.03 ± 0.20% and 65.49 ± 1.39%, respectively, after 24 hours. When the coagulation treatment method was applied to increase phosphorus removal rate from the effluent of microbubble-oxygen treatment, the phosphorus was removed up to 92.7%. However, the removal rate of organic pollutants (TCOD) was as small as 28.7 ± 0.2% within the first 6 hours, and then the negligible removal of TCOD was recorded. This study suggests that microbubble-oxygen can be applied not only livestock manure but also aeration tank of various wastewater treatment plant, which can reduce the load on the associated unit process and produce stable high-quality effluent.

새로운 선회유동형 미세기포 발생기를 적용한 직접접촉식 막증류 공정의 성능평가

김유빈(Yu-Bin Kim),함민규(Min-Gyu Ham),김영득(Young-Deuk Kim) 대한기계학회 2017 대한기계학회 춘추학술대회 Vol.2017 No.11

In previous studies on DCMD process, it has been found that the microbubbles play a significant role in enhancing the heat and mass transfers in the liquid streams, leading to an improvement in the DCMD permeate flux. In this study, a novel swirling flow-type microbubble generator capable of supplying air is thus designed and fabricated for DCMD process. DCMD performance is evaluated for various operating conditions (i.e., air supply flow rate, feed temperature and flow rate) and geometrical (i.e., swirler length and nozzle tip size) conditions so as to demonstrate possibilities offered by the microbubbles. In order to analyze the microbubble characteristics generated by the microbubble generator, the probability distribution of microbubble diameter is inferred from these experimental measurements at assorted operation conditions. It is clearly evident that more microbubbles are generated at higher feed flow rates and lower feed temperatures, resulting in a higher DCMD permeate flux.

연구논문 : 미세기포를 이용한 Microcystis sp. 제거에 관한 연구

형성희 ( Sung Hee Hyung ),이갑두 ( Kap Du Lee ),박상원 ( Sang Won Park ) 한국환경과학회 2016 한국환경과학회지 Vol.25 No.3

This study carried out zeta potential measurements of the Microcystis sp. under various solutions condition and investigated the characteristics of Microcystis sp. through the size control of microbubbles to eliminate algae that causes problems in aquatic ecosystems and human activities. DAF process was adopted and several coagulants were used to remove the Microcystis sp. CCD Camera was used to measure and analyze the size of microbubble, and fluorescent microscope was used to observe the particle, algae species and community. Zeta potential behavior of the algae was analyzed by using ELS-Z. Lab-scale and pilot-scale experiments were conducted to test flotation process. Polyaluminium chloride(PAC) coagulant was used, and the removal efficiency of the algae was assessed through Chlorophyll-a analysis. In the Lab-scale experiment, 2.2 ppm, 11 ppm, 22 ppm, and 44 ppm of polyaluminium chloride was injected to coagulate the algae. The coagulated algae was floated by the microbubble. The microbubbles in the experiments were generated at a air pressure of 450~550 kPa. The microbubble size was controlled in 36 ㎛, 100 ㎛, and 200 ㎛, respectively by using different diffuser. The results of lab-scale experiments on flotation plant indicated that the average removal rate was about 90% or above for 11 ppm, 22 ppm, and 44 ppm of polyaluminium chloride. On the other hand, in the pilot-scale experiment, the removal efficiency was in the range of 85% to 95% in all dose ranges of polyalumium chloride and aluminium sulfate coagulants.

Simultaneous nitrification and denitrification by using ejector type microbubble generator in a single reactor

Young Ji-Young Lim,Hyun-Sik Kim,Soo-Young Park,Jin-Han Kim 대한환경공학회 2020 Environmental Engineering Research Vol.25 No.2

This study was performed to verify the possibility of nitrification and denitrification in a single reactor. In batch type experiment, optimal point of experimental conditions could be found by performing the experiments. When supply location of microbubbles was located at half of width of the aeration tank and operating pressure of 0.5 bar, it was possible for zones in the aeration tank to be separated into anoxic and aerobic by controlling air suction rate according to operating pressure of the generator. To be specific, the concentration of dissolved oxygen (DO) in zone 1 and 2 of the aeration tank could be maintained as less than 0.5 mg/L. Also, in the case of concentration of oxygen in zone 3 and 4, the concentration of DO was increased up to 1.7 mg/L due to effects of microbubbles. In continuous flow type experiment based on the results of batch type experiments, the removal efficiency of nitrogen based on T-N was observed as 39.83% at operating pressure of 0.5 bar and 46.51% at operating pressure of 1 bar so it was able to know that sufficient air suction rate should be required for nitrification. Also, denitrification process could be achieved in a single reactor by using ejector type microbubble generator and organic matter and suspended solid could be removed. Therefore, it was possible to verify that zones could be separated into anoxic and aerobic and nitrification and denitrification process could be performed in a single reactor.

Microbubble-cloud behavior Simulation to Improve Focused Ultrasound Heating Effect using an Ultrasound Contrast Agent

Kyoungwon Shin,Byeongcheol Yoo,Heungho Choi 대한전자공학회 2021 IEIE Transactions on Smart Processing & Computing Vol.10 No.5

The thermal effect ability of an ultrasound contrast agent (UCA) in high-intensity focused ultrasound (HIFU) therapy was evaluated. This was done using a thermal effect simulation program using a microbubble-cloud model and modified Pennes Bio-Heat Transfer Equation (BHTE). In order to design the proposed simulation program, a spherical microbubble-cloud model was developed. Next, the proposed simulation program was experimentally investigated by ultrasound phantom experiments using commercial HIFU equipment and UCA, and the change of thermal effect according to the microbubble-cloud population ratio was measured. The HIFU thermal effect simulations using the properties of UCA were compared with the phantom experiments, which provided concordant results.