Seawater evaporation and purification powered by solar energy are considered as a promising approach to alleviate the global freshwater crisis, and the development of photothermal materials with high efficiency is imminent. In this study, cellulose nanofiber (CNF)/MXene/Ni chain (CMN) aerogels were successfully synthesized by electrostatic force and hydrogen bond interaction force. CMN10 achieved a favorable evaporation rate as high as 1.85 kg m− 2 h− 1 in pure water, and the corresponding evaporation efficiency could be up to 96.04%. Even if it is applied to seawater with multiple interference factors, its evaporation rate can still be 1.81 kg m− 2 h− 1. The superior seawater evaporation activity origins from the promoted separation of photoexcited charges and photothermal conversion by the synergy of Ni chain and MXene, as well as the water transport channel supported by the 3D structure frame of CNF. Most importantly, CMN aerogel can maintain water vapor evaporation rates above 1.73 kg m− 2 h− 1 under extreme conditions such as acidic (pH 2) and alkaline (pH 12) conditions. In addition, various major ions, heavy metals and organic pollutants in seawater can be rejected by CMN10 during desalination, and the rejection rates can reach more than 99.69%, ensuring the purity of water resources after treatment. This work shows the great potential of CMN aerogel as a high-efficiency solar evaporator and low-cost photothermal conversion material. Cellulose nanofiber (CNF)/MXene/Ni chain (CMN) aerogels demonstrated high evaporation of water from sea water.

In this study, a two-stage electrostatic precipitator (ESP) was developed using a novel automatic dry cleaning device to reduce the ultrafine particles in subway stations. Collection efficiency was evaluated with a pilot scale ESP (1.2m× 1.2m) and the scale of the test duct was half of the subway air handling unit. The maximum collection efficiency for 0.3 μm particles was 96.9%. In addition, we studied a method of automatic dry cleaning for maintenance of the ESP. The cleaning efficiency was analyzed according to the cleaning flow rate for each particle loading amount to achieve a recovery rate over 90%. In addition, we derived the equation to estimate the reduction in collection efficiency according to the particle loading amount. It was confirmed that the performance of the contaminated ESP was restored to the initial state by the automatic dry cleaning in this study and that the electrical energy consumption was 5 times lower compared to utilizing conventional water cleaning.

본 연구에서는 강화되는 황산화물 및 입자상물질의 배출규제를 만족시키기 위한 후처리장치로 습식전기집진기에 대한 실험적 연구를 수행하였다. 실험을 위해 선박용 중유(HFO, 황함유량 약 2.1%)를 연료로 사용하는 선박용 4행정 디젤엔진(STX-MAN B&W)을 활용 하였으며, 연돌에 설치된 습식전기집진기 입/출구에서 측정을 실시하였다. 미세먼지 측정을 위해서는 광학식 계측기(OPA-102) 및 중량농 도측정방식(Method 5 Isokinetic Train)을 이용하였으며, 황산화물 계측을 위해서는 FT-IR(DX-4000)을 사용하였다. 엔진부하는 50%, 75%, 100%로 변화시키면서 실험을 실시하였다. 실험 결과로, 엔진부하가 50%에서 100%로 변화함에 따라 미세먼지 저감 효율은 모든 부하 조건에서 94~98% 정도의 높은 저감 효율을 나타내었다. 추가적으로 습식전기집진기 퀜칭존에서 배기가스의 온도를 낮추는 과정 중 세정액에 의한 이산화황(SO2) 저감을 확인할 수 있었으며, 저감율은 엔진부하에 따라 55%~81%로 확인되었다.

본 논문에서는 정전기 흡착패드를 구성하는 곡면형 전극의 기하학적 엄밀성을 고려하기 위해 정전기 문제에 대하여 CAD에서 사 용하는 NURBS 기저함수를 직접 사용하는 아이소-지오메트릭 해석 기법을 도입하였다. 정전기 흡착력을 곡선 접촉면에서 구하는데 법선 벡터의 영향이 크므로 엄밀한 기하형상을 고려하는 아이소-지오메트릭 해석이 강점을 갖는다. 수치 예제를 통해 곡면과 평면에서 반복 구조의 유무에 따른 파라메터 연구를 수행하여 곡면형 전극의 흡착력이 좋은 성능을 가짐을 보였다. 정전기 흡착력의 성분을 분석하였을 때 정전기 흡착력의 차이는 법선 성분 전기장의 증가로 인한 것으로 파악되었다. 결론적으로 곡면형 전극에서도 전극 사이 거리가 가까워지는 아래로 볼록인 경우가 가장 성능이 좋고, 위로 볼록인 경우에는 성능이 가장 낮음을 보였다.

The purpose of this study was to develop synbiotic materials and to apply them to the puffed grain products using electrostatic spraying technology. Lactic acid bacteria were isolated from Kimchi and selected through tests of acid resistance, bile salt resistance and γ-aminobutyric acid (GABA) content. The isolated Lactobacillus brevis CFM21 produced highest GABA production up to a concentration of 926.42 μg/mL when grown in MRS broth containing 0.8% MSG. The possibility of coated grains as a prebiotic material was evaluated Confocal laser scanning micro scopy (CLSM). Rice bran extract containing 2% dextrose, 2% soytone, 0.2% potassium chloride, 0.6% MSG was produced 524.77 μg/mL of GABA. Citrus sinensis oil showed the highest antibacterial activity against Clostridium perfringens Electrostatic spray showed much higher effectiveness than conventional spray in coating the puffed grain product through CLSM. Applying Rice bran culture and Citrus sinensis oil to puffed grain product using electrostatic spray could contribute to promote intestinal health of consumers.

전 세계 90 %의 인구가 WHO의 연평균 미세먼지 노출 기준(10 ㎍/㎥)을 초과한 공기를 흡입하고 있다. 전 세계적으로 육상뿐 만 아니라 해양에서 발생하는 질소산화물에 대한 규제를 통해 2차 오염물질, 초미세먼지 저감에 대해 노력하고 있으며 국내에서는 선박에서 미세먼지 발생의 주요한 원인인 황 함유량 저감과 환경친화적 선박의 개발 및 보급 등을 통해 깨끗한 해양환경 조성을 위한 노력을 하고 있다. 디젤엔진 유해 배출가스 저감을 위한 기술 중 압력 손실이 적고 높은 집진 효율 및 NOx의 제거와 유지 관리의 장점이 많은 전기 집진기의 수요와 중요성이 증가하고 있다. 본 연구는 총톤수 999톤급 선박의 2,427 kW 선박용 디젤엔진의 미세먼지 저감을 목적으로 개발된 전기 집진기를 예지보전단계에서 고장모드영향분석을 통해 장비 품질을 높여 선박 내에서의 내구연한을 높이고자 위험 우선순위 도출하였다. 위험 우선순위는 고장모드 241(poor dust capture efficiency)이 RPN 180으로 가장 높았다. Collecting electrode 에서 가장 많은 고위험 고장모드를 검출하여 집중관리 부품으로 관리해야 할 필요가 있었으며 원인으로 진동과 핀 풀림으로 인한 유 격 불량이 가장 많이 검출되었다. 핀 풀림 역시 근본적으로는 선체 또는 장비에서 발생하는 진동이 원인이 되어 발생할 수 있는 사항이기 때문에 핀 풀림이 발생하는 개소에 보완이 필요하겠다.

Porous metals demonstrate not only excessively low densities, but also novel physical, thermal, mechanical, electrical, and acoustic properties. Thus, porous metals exhibit exceptional performance, which are useful for diesel particulate filters, heat exchangers, and noise absorbers. In this study, SUS316L foam with 90% porosity and 3,000 μm pore size is successfully manufactured using the electrostatic powder coating (ESPC) process. The mean size of SUS316L powders is approximately 12.33 μm. The pore properties are evaluated using SEM and Archimedes. As the quantity of powder coating increases, pore size decreases from 2,881 to 1,356 μm. Moreover, the strut thickness and apparent density increase from 423.7 to 898.3 μm and from 0.278 to 0.840 g/cm3, respectively. It demonstrates that pore properties of SUS316L powder porous metal are controllable by template type and quantity of powder coating.

Al2O3-SiC ceramic composites are produced using pressureless sintering, and their plasma resistance, electrical resistance, and mechanical properties are evaluated to confirm their applicability as electrostatic-discharge-safe components for semiconductor devices. Through the addition of Mg and Y nitrate sintering aids, it is confirmed that even if SiC content exceeded 10%, complete densification is possible by pressureless sintering. By the uniform distribution of SiC, the total grain growth is suppressed to about 1 μm; thus an Al2O3-SiC sintered body with a high strength over 600 MPa is obtained. The optimum amount of SiC to satisfy all the desired properties of electrostatic-discharge-safe ceramic components is obtained by finding the correlation between the plasma resistance and the electrical resistivity as a function of SiC amount.

Microstructure evolutions of thermosetting resin coating layers fabricated by electrostatic spray deposition (ESD) at various processing conditions were investigated. Two different typical polymer systems, a thermosetting phenol-formaldehyde resin and a thermoplastic polyvinylpyrrolidone (PVP), were employed for a comparative study. Precursor solutions of the phenol-formaldehyde resin and of the PVP were electro-sprayed on heated silicon substrates. Fundamental differences in the thermomechanical properties of the polymers resulted in distinct ways of microstructure evolution of the electro-sprayed polymer films. For the thermosetting polymer, phenol-formaldehyde resin, vertically aligned micro-rod structures developed when it was deposited by ESD under controlled processing conditions. Through extensive microstructure and thermal analyses, it was found that the vertically aligned micro-rod structures of phenol-formaldehyde resin were formed as a result of the rheological behavior of the thermosetting phenol-formaldehyde resin and the preferential landing phenomenon of the ESD method.

A single-stage electrostatic precipitator (ESP) was evaluated in terms of its performance in removing dust in subway tunnels. A wire-to-plate type ESP was tested in a small-scale wind tunnel. The effects of wire-to-wire spacing (2040 mm) and the material connecting wire-to-wire on the performance of ESP were investigated, with varying applied voltage and airflow velocity. A narrower wire-to-wire spacing showed higher collection efficiency at the same applied voltage. Lower electrical resistivity of material connecting wire to wire was more effective. Ozone generation in subway tunnel applications was insignificant.

In this study, we numerically analyzed flow and particle transport near the electrostatic precipitator in the tunnel according to train runs. When there was no train running, flow field was formed by a precipitator. Flow emitted from precipitator blocks the path along the tunnel, and therefore most contaminated air passes through the precipitator and can be cleaned. On the other hand, flow pattern during the train run was affected by train induced wind. A strong straight flow was generated at the front of train, and back flow was formed in the opposite line. When a train runs upward only (train start from suction section to blow section), the subway train transports contaminated particles along the tunnel. For downward train runs only case, the cleaned air reentered the contaminated section with train wind. Both train runs case showed combined flow and particle concentration pattern of both single train runs.

In this study, the odor causing in the under-fired charbroiling restaurant was reported in literature investigation,pilot test and field experimental verification. The charbroiling restaurant causes odor complaints of Neighbors soefficient reduction method is requested. Acetaldehyde, ammonia, sulfur compound and the oil mist of white smokeare found to cause odor from the charbroiling restaurant. Pilot test results show that in the removal efficiency ofodor, Electrostatic Precipitation was 67.4%, absorption was 81.2%, adsorption was 74.2% and the ElectrostaticPrecipitation & Adsorption the hybrid system with 85.7% respectively. In the same condition of the hybrid system(Electrostatic Precipitation & Adsorption), the odor removal efficiency were higher when the design parameterssuch as the discharge voltage and current were high. The process efficiency were higher when as the implanterpole was cylindrical. However, the process efficiency rapidly reduced due to the contamination of the processcomponent or material, as the operating time of the equipment is increased. Therefore, fixed maintenance and repairof the equipment is found to be are very important, for long term operation. Therefore, as the experimental resultof this study, applying hybrid system removed odors caused in under-fired charbroiling restaurant which areunregulated, is more effective device that settle civil complaints and preserve environment.

Particle collection efficiency and air cleaning capacity were tested for the two-stage electrostatic precipitator for use in indoor air cleaning systems. A wire-plate type ionizer was used as a particle charger and a dielectric film consisted of polypropylene (or polyethylene) coated metals and zigzagged metal electrodes was used as a particle collector in the electrostatic precipitator. Both particle collection efficiency and air cleaning capacity increased as increasing the applied voltage on the charger and the collector, and furthermore, as increasing the collector film width (i.e. collection area). Air cleaning capacities estimated by the product of particle collection efficiency and air flow rate were quite well consistent with the experimental ones with a proportional constant of 0.964. Ozone concentrations emitted from the charger at the applied voltages of 5.0 and 5.2 kV were less than 0.05 ppm, indoor ozone standards of UL 867-2002, KS C 9314 and SPS-KACA002-132. For the air flow rate of 11.7 m³/min, the applied floor area of 48.2 m² could be obtained when 5.2 kV and 6.0 kV were applied on the ionizer and the collector, respectively and the collector of two 15 mm polyethylene dielectric films was used.

Numerical analysis was conducted to characterize the particle charging quantities in the charging cell of a 2-stage parallel-plate electrostatic precipitator with respect to particle size. The numerical method took into consideration of particle charging rate equations and particle equations of motion, allowing the locally varying non-uniform electric field and ion number concentration along the particle trajectory. The charging rate model developed by Lawless (1996) was used in the present study. According to the present study, the numerical results showed good agreement with the available experimental data.

Electrostatic spinnings were performed with the solutions of PAN/DMF to be nanofiber webs. The diameter of the fibers ranged from 200 nm to 1000 nm depending on the PAN concentration and on the applied DC voltage. The nanofibers were oxidatively stabilized and subsequently carbonized up to 1000℃ with carbonization yield of 40%. The bulk electric conductivity of the carbonized web increased form 6.8×10-3S/cm to 1.96 S/cm while the carbonizaton temperature increased from 700℃ to 1000℃.

대면적 정전 접합 장치를 고안 및 제작하여 Si과 glass를 정전 접합시켰다. 여러 온도에서 정전 접합 후 접합 면적을 측정하였으며 접합이 이루어진 경우 그 접합 면적이 90%를 넘었다. 접합시 전류를 측정하여 접합 강도와의 관계를 살펴보였다. 잔류 공공을 생성시키는 원인은 재료의 표면 거칠기 차이나 전극의 모양보다는 불순물 입자에 의한 것임이 밝혀졌고 같은 크기의 불순물 입자에 대한 공공의 크기는 접합 온도가 높을수록 감소하였다. 정전 접합에 미치는 불순물의 영향을 공공의 크기 및 불순물 입자의 크기를 측정하여 살펴보았다.