• Title/Summary/Keyword: 여과성능

Search Result 388, Processing Time 0.025 seconds

Effect of Water Wash and Dry Temperature in Homogeneous Precipitation Method on the Manufacture of Mn-added Barium Hexaaluminates (균일용액침전법에서 수세여부와 건조온도가 망간이 첨가된 바륨헥사알루미네이트의 제조에 미치는 영향)

  • Park, Ji Yun;Kim, Seo Young;Rhee, Young Woo
    • Korean Chemical Engineering Research
    • /
    • v.59 no.3
    • /
    • pp.435-442
    • /
    • 2021
  • Mn-added Barium hexaaluminates were manufactured by homogeneous precipitation method using Urea. The effects of water wash and dry temperature were analyzed by thermal weight analysis, X-ray diffraction analysis, and scanning electron microscopy. Catalysts that went through the filtration step only produced pure hexaaluminate images compared to those that went through the water wash step. During the drying process, it seems that the remaining urea helps dehydration of the precursor and affects the phase shift of gibbsite to boehmite, which is easy to convert to pure hexaaluminate. The catalyst WO200 gave the best performance in the methane combustion reaction, and NOx was not emitted in the reaction for all catalysts. Hexaaluminates were found to affect reducing the highest CO emissions.

Performance Evaluation of Combined Sewer Overflow Treatment using Filtration Pilot Device (파일럿 여과장치를 이용한 합류식하수관 월류수 처리성능 평가)

  • Lee, Jun Ho;Shin, Young Gyun
    • Journal of Korean Society on Water Environment
    • /
    • v.35 no.5
    • /
    • pp.409-417
    • /
    • 2019
  • In this study, a $480m^3/day$ pilot device was constructed through laboratory experiments based on the Ministry of Environment manual. The purpose of this study was to analyze the characteristics of CSO treatment and backwashing characteristics by applying the pilot device to the field. The purpose of this study was to acquire the basic data necessary for the design and operation management of the real scale filtration type non-point pollution control system. The filtration was conducted while maintaining the linear velocity of 20m/hour. The CSO treatment efficiencies of the pilot devices were 0.4-76.1%(mean 49.0 %), SS 51.4-91.6%(mean 77.8%), COD 22.2-59.4% (mean 38.3%) and TP 14.5-52.6%(mean 38.1%),respectively. The correlation coefficient between SS and the turbidity of influent water was 0.90, higher than that of CSO. To operate the treatment system effectively, the turbidity can be easily measured in real time as the monitoring item is the most appropriate because SS is the main target substance of the non-point source. As a result of analyzing the adsorbent treatment characteristics of PP filter material applied to this pilot device, the average particle diameter range of influent was $4.6-40.1{\mu}m$(mean $21.2{\mu}m$) and the treated water was $0.9-24.5{\mu}m$(mean $6.4{\mu}m$), respectively. Particles of approximately 10m or less are leached out, and so it is necessary to compensate for the raw water containing micro particulate matter.

Skin Barrier Improvement Effect of Exosomal Nanovesicles Derived from Lactic Acid Bacteria (유산균 유래 엑소좀 유사 나노베지클의 피부 장벽 개선 효과)

  • Wang, Hyesoo;Lee, Kwang-Soo;Kang, Yong-Won
    • Journal of the Society of Cosmetic Scientists of Korea
    • /
    • v.47 no.2
    • /
    • pp.171-178
    • /
    • 2021
  • In this study, exosomal-like nano-vesicles derived from probiotics were isolated and various physiological activities were evaluated on the skin. This study show that Lactococcus lactis subsp. lactis (LL) are incubated, and then isolated LL derived exosomal nanovesicles (LVs) at the range of 70 ~ 200 nm by high-pressure homogenizer and ultrafiltration. The vesicle numbers were an average of 1.81 × 1011 particles/mL. This study finds out the bacterial nanovesicles' beneficial effect on the skin. Fibrillin (FBN1) gene expression increased by 23% in fibroblast cells. Fibronectin (FN1) and filaggrin (FLG) gene expression increased by 65% and 400% in keratinocytes. We could see that cornified envelope (CE) formation ability was increased by 30% compared to the control group. Furthermore, collagen type I alpha 1 (COL1A1) protein expression increased by 83% compared to the UV-irradiated control group. These results suggest that LVs could help skin barrier improvement and used as an ingredient for cosmetics or pharmaceuticals.

Enhancing Adhesion between Polyphenylene Sulfide Fabric and Polytetrafluoroethylene Film for Thermally Stable Air Filtration Membrane (열안정 공기 여과막용 폴리페닐렌 설파이드 원단과 폴리테트라플루오로에틸렌 필름 사이의 접착력 향상)

  • Jin Uk Kim;Hye Jeong Son;Sang Hoon Kang;Chang Soo Lee
    • Membrane Journal
    • /
    • v.33 no.4
    • /
    • pp.201-210
    • /
    • 2023
  • Dust filter membranes play a crucial role in human life and various industries, as they contribute to several important aspects of human health, safety, and environmental protection. This study presents the development of a polysulfone@polyphenylene sulfide/polytetrafluoroethylene (PSf@PPS/ePTFE) composite dust filter membrane with excellent thermal stability and adhesion properties for high-temperature conditions. FT-IR analysis confirms successful impregnation of PSf adhesive onto PPS fabric and interaction with ePTFE support. FE-SEM images reveal improved fiber interconnection and adhesion with increased PSf concentration. PSf@PPS/ePTFE-5 exhibits the most suitable porous structure. The composite membrane demonstrates exceptional thermal stability up to 400℃. Peel resistance tests show sufficient adhesion for dust filtration, ensuring reliable performance under tough, high-temperature conditions without compromising air permeability. This membrane offers promising potential for industrial applications. Further optimizations and applications can be explored.

Flat Sheet Polybenzimidazole Membranes for Fuel Cell, Gas Separation and Organic Solvent Nanofiltration: A Review (평막형태의 폴리벤지다미졸 분리막의 연료전지, 기체분리막, 유기물분리용 나노여과막으로의 응용: 총설)

  • Anupam Das;Sang Yong Nam
    • Membrane Journal
    • /
    • v.33 no.6
    • /
    • pp.279-304
    • /
    • 2023
  • Polybenzimidazole (PBI) based membranes have evolved in literature as a popular membrane material for various applications in the past two decades because of their high temperature thermal durability, strong mechanical and tensile properties, high glass transition temperature (Tg), ion conduction ability at elevated temperature (up to 200℃), oxidative or chemical durability along with robust network like structural rigidity, which make PBI membranes suitable for various potential applications in chemically challenging environments. Ion conducting PBI based membranes have been extensively utilized in high temperature proton exchange membrane fuel cells (HT-PEMFC). In addition, PBI based membranes have been vastly utilized for the development of gas separation membranes and organic solvent nanofiltration (OSN) membranes for their unique characteristics. This review will cover the recent progress and application of various types of flat sheet PBI based membranes for HT-PEMFC, gas separation and OSN application.

Nitrification Performance of a Moving Bed Bioreactor (MBBR) at Different Ammonia and Hydraulic Air-Loading Rates under Seawater Conditions (해수 조건에서 총암모니아성 질소 부하량과 수리학적 공기 부하량에 따른 유동상 여과조의 질산화 성능 평가)

  • Jaegeon Lee;Younghun Lee;Jeonghwan Park
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.56 no.6
    • /
    • pp.870-877
    • /
    • 2023
  • The purpose of this study was to assess the efficiency of nitrification based on ammonia loading rates and hydraulic air-loading rates in a moving bed bioreactor (MBBR) under seawater conditions. The goal was to provide foundational data for the design of these bio reactors. At an ammonia loading rate of 0.2 g TAN·m-2 surface area·day-1, the influent TAN concentration was determined to be 1.76±0.33 mg·L-1, which is below the safe concentration for fish survival (2 mg·L-1). Considering operational aspects, the optimal ammonia-loading rate was derived. Subsequently, experimental results for nitrification efficiency at the optimal ammonia-loading rate revealed that the optimum hydraulic air-loading rate was 1.8 L·air·m-2 surface area·min-1. This condition resulted in the lowest concentrations of TAN and NO2-N in the influent water, thus establishing the optimal hydraulic air-loading rate. A regression equation was derived for the ammonia-removal rate (Y) based on the ammonia-loading rate (x) and expressed as a 0.5-order equation (Y=ax0.5+b). Specifically, for TAN concentrations of 0-6 mg·L-1, the regression equation Y=0.1683x0.5-0.13628, was established.

Clustering Method based on Genre Interest for Cold-Start Problem in Movie Recommendation (영화 추천 시스템의 초기 사용자 문제를 위한 장르 선호 기반의 클러스터링 기법)

  • You, Tithrottanak;Rosli, Ahmad Nurzid;Ha, Inay;Jo, Geun-Sik
    • Journal of Intelligence and Information Systems
    • /
    • v.19 no.1
    • /
    • pp.57-77
    • /
    • 2013
  • Social media has become one of the most popular media in web and mobile application. In 2011, social networks and blogs are still the top destination of online users, according to a study from Nielsen Company. In their studies, nearly 4 in 5active users visit social network and blog. Social Networks and Blogs sites rule Americans' Internet time, accounting to 23 percent of time spent online. Facebook is the main social network that the U.S internet users spend time more than the other social network services such as Yahoo, Google, AOL Media Network, Twitter, Linked In and so on. In recent trend, most of the companies promote their products in the Facebook by creating the "Facebook Page" that refers to specific product. The "Like" option allows user to subscribed and received updates their interested on from the page. The film makers which produce a lot of films around the world also take part to market and promote their films by exploiting the advantages of using the "Facebook Page". In addition, a great number of streaming service providers allows users to subscribe their service to watch and enjoy movies and TV program. They can instantly watch movies and TV program over the internet to PCs, Macs and TVs. Netflix alone as the world's leading subscription service have more than 30 million streaming members in the United States, Latin America, the United Kingdom and the Nordics. As the matter of facts, a million of movies and TV program with different of genres are offered to the subscriber. In contrast, users need spend a lot time to find the right movies which are related to their interest genre. Recent years there are many researchers who have been propose a method to improve prediction the rating or preference that would give the most related items such as books, music or movies to the garget user or the group of users that have the same interest in the particular items. One of the most popular methods to build recommendation system is traditional Collaborative Filtering (CF). The method compute the similarity of the target user and other users, which then are cluster in the same interest on items according which items that users have been rated. The method then predicts other items from the same group of users to recommend to a group of users. Moreover, There are many items that need to study for suggesting to users such as books, music, movies, news, videos and so on. However, in this paper we only focus on movie as item to recommend to users. In addition, there are many challenges for CF task. Firstly, the "sparsity problem"; it occurs when user information preference is not enough. The recommendation accuracies result is lower compared to the neighbor who composed with a large amount of ratings. The second problem is "cold-start problem"; it occurs whenever new users or items are added into the system, which each has norating or a few rating. For instance, no personalized predictions can be made for a new user without any ratings on the record. In this research we propose a clustering method according to the users' genre interest extracted from social network service (SNS) and user's movies rating information system to solve the "cold-start problem." Our proposed method will clusters the target user together with the other users by combining the user genre interest and the rating information. It is important to realize a huge amount of interesting and useful user's information from Facebook Graph, we can extract information from the "Facebook Page" which "Like" by them. Moreover, we use the Internet Movie Database(IMDb) as the main dataset. The IMDbis online databases that consist of a large amount of information related to movies, TV programs and including actors. This dataset not only used to provide movie information in our Movie Rating Systems, but also as resources to provide movie genre information which extracted from the "Facebook Page". Formerly, the user must login with their Facebook account to login to the Movie Rating System, at the same time our system will collect the genre interest from the "Facebook Page". We conduct many experiments with other methods to see how our method performs and we also compare to the other methods. First, we compared our proposed method in the case of the normal recommendation to see how our system improves the recommendation result. Then we experiment method in case of cold-start problem. Our experiment show that our method is outperform than the other methods. In these two cases of our experimentation, we see that our proposed method produces better result in case both cases.

Effects of Alkalinity on the Nitrification Capability of Nonwoven Fabric Filter Bioreactor (부직포 여과막 생물반응조에서 알칼리도가 질산화 성능에 미치는 영향)

  • Bae, Min-Su;Ahn, Yoon-Chan;Jang, Myung-Bae;Cho, Yun-Kyung;Cho, Kwang-Myeung
    • Journal of Korean Society of Environmental Engineers
    • /
    • v.29 no.7
    • /
    • pp.783-792
    • /
    • 2007
  • To investigate the effects of alkalinity on the nitrification capability of the nonwoven fabric filter bioreactor(NFBR), an experiment was performed for 641 days at a hydraulic retention time of approximately 11 hours by changing the influent concentration of $NH_3-N$ from 54 mg/L to 1,400 mg/L and alkalinity from 43 mg/L to 10,480 mg/L. The MLSS concentration reduced from an initial value of 2,650 mg/L down to 830 mg/L, then increased up to 8,340 mg/L. Though the volumetric loading rate varied in a range of $0.120\sim3.130$ kg $NH_3-N/m^3-day$, the F/M ratio showed a narrow range of $0.067\sim0.414$ kg $NH_3-N/kg$ MLSS-day. The average nitrification efficiency at each experimental stage resulted in the range of $35.2\sim100%$, and the maximum nitrification rate was 2.970 kg $N/m^3-day$ or 0.489 g N/g MLVSS-day. The nitrifiers' fraction of the MLVSS increased up to 100% from an initial value of 7.1% and the biofilm formed on the nonwoven fabric filter showed a very low nitrifiers' fraction of mere 2.2%. The growth yield of the MLSS and the alkalinity consumption rate were computed to be 0.117 g VSS/g N removed and 7.08 g alkalinity/g $NO_x^--N$ produced, respectively. Results of the research suggest that NFBR could be an adequate process for nitrification of wastewaters with high ammonia concentrations.

A Study on Fouling Characteristics and Applicability of Fouling Reducer in Submerged MBR Process (침지형 MBR공정에서 파울링 특성과 파울링 완화제의 적용성에 관한 연구)

  • Park, Jun Won;Park, Hong June;Kim, Min Ho;Oh, Yong Keol;Park, Chul Hwi
    • Journal of Korean Society of Environmental Engineers
    • /
    • v.35 no.5
    • /
    • pp.371-380
    • /
    • 2013
  • Though MBR process has many advantages, the greatest risk factors in operating MBR process are occurrence of membrane fouling and decrease of flux. It is very difficult to find exact mechanism due to complex influence by many effects, although there have been recently many studies of membrane fouling. The purposes of this study are firstly evaluating bioreactor of lab-scale and micro-filtration hollow fiber membrane, secondly investigating correlation between foulants affecting membrane performance and membrane fouling, and lastly evaluating various parameters affecting fouling and applicability of membrane fouling reducer. This study found that TMP was increasing rapidly and showed 0.32 bar and the average of flux was 88 LMH. EPS concentration tends not to change much above MLSS concentration (6,000 mg/L). However, EPS concentration variation is wide below MLSS concentration (6,000 mg/L). Also, from results of membrane surface condition and element analysis using SEM/EDX, carbon and fluorine were founded to be the highest percentage in membrane because of characteristics of membrane material. In operating continuously, inorganic fouling was generated by increase of these inorganic substances such as $Al^{3+}$ and $Mg^{2+}$. Lastly, the best filtration performance was obtained for 0.03 mg MFR/mg MLSS by results of particle size, zeta potential, $SCOD_{cr}$, EPS and MLSS concentration.

The Effect of Filter Media on the Biofiltration of Air Contaminated by Toluene (톨루엔으로 오염된 공기의 생물학적 여과에 대한 필터용 담체의 영향)

  • 홍성도;한희동;명성운;최호석;김인호
    • KSBB Journal
    • /
    • v.16 no.6
    • /
    • pp.603-608
    • /
    • 2001
  • In this study, we studied on the remeval of toluene vapors in a lab-scale biofilter. Biofiltration was performed in a column fed downflow with contaminated air at ambient conditions. The column was packed with mixture of Peat and Calstene(5:3 vol. Ratio), Synthesized media, Bark and Wood chip, which were inoculated with microbial population of selected stains(Pseudomonas. putida, KCCM 11343, ATCC 12633). The microorganisms were immobilized on the bed medium and then biofilm were formed. The biofilter was operated under the conditions of various inlet toluene concentrations for 180 days and treated up to the elimination capacity of maximum 40 g/㎥hr at the inlet load of 30 g/㎥ hr with percentage removals of 20∼90% and gas retention times between 1 and 2 min. The pressure drop was very negligible through the biofilter columps because its value of 0.054 cmH$_2$O/m was much less than others. The effect of operating conditions such as flow rate, inlet toluene concentration and moisture contents on the performance of the biofilter was sequentially investigated in this study.

  • PDF