• Membrane Journal
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• v.11 no.4
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• pp.152-160
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• 2001

The pretreatment for COD removal of acrylic wastewater and separation characteristics of ultrafiltration hollow fiber type module and reverse osmosis spiral wound type module with the variation of applied pressure and temperature were discussed. Thc optimum washing time of membranes was decided with long team operation and the degree of fouling was discussed with operating time. Permeate flux was decreased rapidly at 14 hrs and that of reverse osmosis membrane was indicated similarly. CaO find sand filter for the first step, neutralization process with treated acrylic wastewater as the second step, UF/RO processes were used as final strep. It was shown treat COD and TDS were below allowable discharge value with the result.

• Korean Journal of Materials Research
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• v.29 no.5
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• pp.277-281
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• 2019

The objective of this research is to evaluate the effect of adhesive types on dimensional stability of bamboo-oriented particleboard. The materials used in this research are bamboo tali(Gigantochloa apus J.A & J.H. Schult. Kurz), UF/MDI(8, 10, 12 % level), and MF, MDI, and PF at 7 % level. Particle and adhesive are mixed using a blending machine; then, mat forming and hot pressing processes are performed using adhesive-suitable temperature and time references. MDI resin is set at $160^{\circ}C$ temperature for 5 minutes. PF resin and MF resin are pressed at $170^{\circ}C$ for 10 minutes, and $140^{\circ}C$ for 10 minutes, respectively, while UF/MDI sets at temperature of $140^{\circ}C$ for 10 minutes. The results show that particleboard using PF resin produces the lowest thickness swelling value. The particleboard using UF/MDI resin also produces good response for thickness swelling value. Interesting things happen in that UF/MDI adhesive produces a thickness swelling value better than that of MDI resin. FTIR analysis on particleboard bonded by UF/MDI resin combination shows the presence of carbonyl group C=O vibration on multi substitution of urea at wave number of around $1,700cm^{-1}$.

• Journal of Dairy Science and Biotechnology
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• v.41 no.3
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• pp.149-156
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• 2023

Milk protein is often fractionated/concentrated by using various techniques in dairy industries. Among these techniques, ultrafiltration (UF) is particularly efficient at concentrating the casein fraction of milk protein. The objectives of this study were to produce casein hydrolysates by concentrating the casein fraction in skim milk using the UF technique and to investigate the chemical composition of the casein hydrolysates. The skim milk was concentrated using a UF laboratory test unit equipped with 10 kDa and 30 kDa membranes. After UF, the protein content of the milk was concentrated up to ~7.2% and the Ca was concentrated up to ~196 mg/100 g of milk. Trypsin was then added to the concentrated skim milk to produce the casein hydrolysates. The results of sodium dodecyl sulphate-polyacrylamide gel electrophoresis showed that the casein fraction was not present after hydrolysis, indicating that casein in the milk had been hydrolyzed. The Ca content in the casein hydrolysates was much higher (p<0.05) compared to Ca content in commercial casein phosphopeptides (CPP) indicating that was acidified during the manufacture of commercial CPP. In conclusion, it seems that casein hydrolysates containing large concentrations of protein and Ca can also be made from concentrated UF milk without acidification or renneting.

• Proceedings of the Membrane Society of Korea Conference
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• 1996.10a
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• pp.64-66
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• 1996

원수 중의 오염물의 양과 종류가 급격히 증가함에 따라 기존의 정수방법은 점차 그 한계를 노출하고 있다. 이러한 문제점의 대안으로 최근 막분리기술을 도입한 고도정수처리공정이 주목되고 있다. 역삼투(reverse osmosis)와 나노여과(nanofiltration)등의 분리막을 이용한 정수처리 공정에 대한 연구가 활발히 진행되어 왔으나, 경제성이 보다 큰 한외여과(ultrafiltration, UF)와 부날활성탄(powdered activated carbon, PAC)의 결합 시스템의 도입이 연구되고 있다. 따라서 본 연구에서는 PAC-UF 시스템의 유입수에 배경물질(background organic matters, BOM)을 포함한 이성분계에서 미량유기물의 경쟁적 흡착 거동을 고찰하였다.

• Proceedings of the Membrane Society of Korea Conference
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• 1997.10a
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• pp.135-136
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• 1997

1. 서론 : 친수성 고분자와 소수성 고분자를 blend한 것을 막재료로 뛰어난 투과 특성을 가진 고분자막을 개발하기 위하여 제막 및 UF 투과실험을 하였다. 이 blend막은 안정성이 있고, 기계적 강도가 뛰어나기 때문에 인공투석막으로서 상당히 흥미있는 막재료이다. 이런 관점에서 친수성 고분자로서 poly(vinyl-alcohol)[PVA]을 기본재료로 하여, 여기에 각종 소수성 고분자를 blend 시키는 막에 관한 검토가 필요하다.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.5
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• pp.684-690
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• 2002

The microcapsules containing fragrant material as functional compound were produced by in-situ polymerization. The prepolymer was made from urea-formaldehyde(UF) and melamine-formaldehyde(MF) as wall materials of microcapsules. The effects of wall material, dispersing agent and ratio of wall material to core material on the mean diameter variation were investigated. Thermal efficiency and release behavior of microcapsules were measured. The resultant UF and MF microcapsules are capable of preserving fragrant oil for long self-life.

• Proceedings of the Membrane Society of Korea Conference
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• 1993.10a
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• pp.77-78
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• 1993

쥬스제조시 청징공정에 있어서 UF의 응용은 현재까지 그리 주목받아 오지 못했다. 그러나 UF는 기존의 여과방법보다 더 간단하고 저렴한 기술이며 더 좋은 품질의 제품을 생산할 수 있다. 일반적인 사과쥬스 제조에 있어서 기존의 청징방법은 보통 2단계를 필요로 하는데 먼저 Pectinase와 같은 효소처리된 원료쥬스를 Decanter라는 회전진콩 여과기로 여과한 다음 가압여과기로 여과를 하게 된다. 이 두단계에 있어서 많은 양의 규조토가 필요한데 UF를 사용하여 청징여과를 하게 되면 규조토의 사용을 안하므로 생산비 절감 뿐만아니라 폐기물처리 문제까지도 해결해 준다. 도한 제품의 질, 특히 덫징도가 증가하며 수율도 높일 수 있고 노동비를 절감할 수 있으며, 효소는 막을 통과하지 않기 때문에 농축액에 축적되어 효소의 재사용에 따른 효소사용량 절감을 가져올 수 있다.

• Korean Journal of Agricultural Science
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• v.36 no.1
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• pp.11-18
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• 2009

The purpose of this study is to examine a proper amount of addition and a proper point for addition of titanium dioxide for the manufacture of E0 type of urea-formaldehyde resin (UF). The reduction of free formaldehyde from UF resin treated particle board was also investigated. $TiO_2$ content was 0.5%, 1% and 3% on the dry basis of UF resin. UV light was used to initiate reaction. The results of this study are as follows: 1. During UF resin manufacturing process, the second adding step of urea was proper point for $TiO_2$ addition. 2. 1 % addition of $TiO_2$ gave good values for the Eo type urea-formaldehyde resin. 3. There was no significant difference between physical properties of particle board, but the higher the adding content of titanium dioxide resulted in the lower the mechanical properties.

• Membrane Journal
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• v.9 no.1
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• pp.17-24
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• 1999

Milk was concentrated by commercial tubular membranes, The permeation rate reduction of hydrophilic membranes (sulfonated poly sulfone (SPSf), polyacrylonitrile (PAN), cellulose acetate (CA)) was found not to be large but hydrophobic membranes to be pronounced considerably, In the case of UF concentration total solids, proteins, fats and minerals were increased as concentrated but carbohydrates decreased. NF showed the same behavior except carbohydrates showing small reduction rate.

• Journal of the Korean Society of Marine Environment & Safety
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• v.4 no.1
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• pp.49-56
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• 1998

The Microfiltration and Ultrafiltration were used to treat effluent of secondary municipal wastewater treatment system(Sequencing Batch Reactor). The cross-flow hollow fiber, UF 500,000(NMWC) and MF 0.65$\mu$ membrane were selected as suitable membrane. Short term and long term fouling effect were measured as a factor of flux decrease and the fouling removal effect of mixing air bubble in the penetrant was studied. The removal of anionic sulfactants before and after formation of micelle with several kinds of oil were checked. The test results show that removal of TOC was 70~80%, TN 28% and TP 16%. The decrease of flux due to fouling were 85%(UF) and 90%(MF) after running of 100hrs. The removal of anionic sulfactants were 60~70% notwithstanding micelle or not.