Membrane fabrication is a critical area that hampers forward osmosis (FO) technology from industrialization. Herein, electrospun poly(vinyl alcohol) (PVA) nanofiber (NF) was used as a support layer for thin film composite (TFC) FO membrane. The PVA NF was incorporated with sulfonated graphene oxide (sGO). The oxygenous-rich sGO enhanced the hydrophilicity and mechanical strength of PVA NF as revealed by contact angle and tensile strength measurements, and pure water flux. On this support, the active polyamide layer was formed through interfacial polymerization. Meanwhile, FO performance of sGO/PVA TFC membrane is currently being evaluated. This work was supported by NRF of Korea funded by the Ministry of Science and ICT (2016R1A2B1009221 and 2017R1A2B2002109) and Ministry of Education (2009-0093816 and 22A20130012051 (BK21Plus)).

In order to develop combination air filters for air conditioners, 2 types of charging section were constructed. One was the wire-plate type and the other was the scroll type. Each charging section was combined with the same electrostatic polypropylene (PP) media. NaCl aerosol particles with geometric mean diameter of 0.05∼0.16㎛, geometric standard deviation of 1.6∼1.9 and total number concentration of 1,700∼24,000 particles/㎤ were used to determine collection efficiencies of the combination air filters for air conditioners with respect to particle size. It was shown that the scroll type combination air filter has greater collection efficiencies and lower pressure drops than the wire-plate type one does.

본 연구는 영상의 노이즈 감소를 위한 복합필터 제안과 간 초음파영상에서 노이즈 제거를 통한 영상품질의 향상으로 정확한 영상 해석에 도움을 주고자 하였다. 실험은 ATS-539 다목적용 초음파팬텀을 이용하여 Gaussian blurring filter, Sharpening filter, Median filter의 조합으로 상위 7개의 복합필터를 선정하고 이를 간 초음파영상에 적용하였다. 그 결과 상위 7개 복합필터 적용하였을 때 SNR, CNR, MSR 값이 모두 증가하는 것으로 나타났다. 이 중 복합필터 1과 2가 가장 높은 값을 나타내었다. 또한 PSNR 30 dB이상, SSIM 1에 가까운 결과값을 나타내어 영상의 손실률이 적음을 알 수 있었다. 따라서 본 연구에서 제안한 복합필터의 적절한 적용은 정확한 영상의 판독과 해석에 도움을 줄 수 있을 것이다.

The removal characteristics of composite odor and malodorous substances using 33 biofilters in sewage treatment facilities were investigated. The geometry mean values of composite odor and odor quotient were reduced by 52.7% and 59.2% at the outlet of the biofilters, respectively. The removal efficiencies of the biofiltes for the composite odor and odor quotient show a significant difference statistically(p=0.000<0.05). The median value of odor quotient of sulfur compounds was reduced by 69.1% at the outlet of the biofilter and the odor quotient of the sulfur compound at the inlet and outlet of the biofilter shows a significant difference statistically(p=0.000<0.05); on the other hand, those of the NH3 and trimethylamine, aldehydes, VOCs and alcohols, organic acids do not.

A biofiltration system using activated carbon/polyurethane composite as solid support inoculated with Bacillus sp. was developed for treating a gaseous stream containing high concentrations of H2S. The effects of operating condition such as the influent H2S concentration and the empty bed contact time (EBCT) on the removal efficiency of H2S were investigated. The biofilter showed the stable removal efficiencies of over 99 % under the EBCT range from 15 to 60 sec at the 300 ppmv of H2S inlet concentration. When the inlet concentration of H2S was increased, the removal efficiencies decreased, reaching 95 and 74%, at EBCTs of 10 and 7.5 sec, respectively. The maximum elimination capacity in the biofilter packed with activated carbon/polyurethane composite media was 157 g/m3/hr.