난류경계층이 유지되기 위한 에너지 공급은 경계층 내 구조물인 와류들의 상호작용으로 끊임없이 이루어진다. 이러한 난류 유동은 수송분야의 마찰저항 및 해양구조물의 침식 및 진동을 유발하기 때문에 유동 제어를 위한 연구가 활발히 진행되고 있다. 이러한 제어의 극대화를 위해서는 난류 에너지 전달이 어떻게 이루어지는지에 대한 메카니즘 규명이 필수적이고, 이를 위해서는 층류경계층 내 유동현상으로 파악하는 것이 명확하고 용이하다는 장점이 있다. 따라서, 본 연구에서는 층류경계층 내 평판에 반구를 설치하여 역압력구배을 발생시킴으로써 교란된 유동현상의 상호작용을 분석하였다. 즉, 반구를 둘러싼 목걸이 와류와 반구 표면의 유동 박리에 의한 후류영역에서 머리핀 와류가 생성되어 상호 유기적으로 영향을 주고받는다. 이 과정에서 목걸이 와류는 후류영역으로 높은 운동량의 유체를 유입시켜 머리핀 와류의 발생 주파수를 증가시킨다. 반구 전방에 구멍을 뚫어 국부적인 흡입제어로 목걸이 와류의 와도를 감소시킴으로써 그 영향이 완화되는 과정을 유동 가시화 및 열선유속계로 측정하여 정성 및 정량적으로 분석하였다.

This study investigated phosphorus removal from secondary treated effluent using coagulation-membrane separation hybrid treatment to satisfy strict regulation in wastewater treatment. The membrane separation process was used to remove suspended phosphorus particles after coagulation/settlement. Membrane separation with 0.2 μm pore size of micro filtration membrane could reduce phosphorus concentration to 0.02 mg P/L after coagulation with 1 mg Al/L dose of polyaluminum chloride (PACl). Regardless of coagulant, the residual concentration of phosphorus decreased as the dose increased from 1.5 to 3.5 mg Al/L, while the target concentration of 0.05 mg P/L or less was achieved at 2.5 mg Al/L for the aluminum sulfate (Alum) and 3.5 mg Al/L for PACl. Moreover, alum showed better membrane flux as make bigger particles than PACl. Alum showed a 40% of flux decrease at 2.5 mg Al/L dose, while PACl indicated a 50% decrease of membrane flux even with a higher dose of 3.5 mg Al/L. Thus, alum was more effective coagulant than PACl considering phosphorus removal and membrane flux as well as its dose. Consequently, the coagulation-membrane separation hybrid treatment could be mitigate regulation on phosphorus removal as unsettleable phosphorus particles were effectively removed by membrane after coagulation.

Soybean straw (SS)-based activated carbon was employed as a precursor to prepare carbon molecular sieves (CMSs) via chemical vapor deposition (CVD) technique using methane as carbon source. Prior to the CVD process, SS was activated by 0.5 wt% ZnCl2, followed by a carbonization at 500°C for 1 h in N2 atmosphere. N2 (77 K) adsorption-desorption and CO2 (273 K) adsorption tests were carried out to analyze the pore structure of the prepared CMSs. The results show that increasing the deposition temperature, time or methane flow rate leads the decrease in N2 adsorption capacity, micropore volume and average pore diameter of CMSs. The adsorption selectivity coefficient of CO2/CH4 achieves as high as 20.8 over CMSs obtained under the methane flow rate of 30 mL min–1 at 800°C for 70 min. The study demonstrates the prepared CMSs are a candidate adsorbent for CO2/CH4 separation.

홍삼 제조 부산물인 홍삼박은 항산화 등 생리활성을 보여줌에 따라 건강기능식품 소재로의 가능성이 높아가고 잇다. 본 연구에서는 홍삼박으로 부터 조산성다당체 추출하고 다당체중에서 항산화 능을 보여주는 산성다당체를 분리 및 정제를 하였다. 계속해서 FT-IR 및 NMR을 이용하여 분자구조적 특성을 분석하였다. 산성다당체의 추출은 10%(w/v) 홍삼박 용액을 원심분리기를 이용하여 불순물을 제거하고 ethanol, methanol, propanol, acetone 및 butanol을 이용하여 최적 용매를 선정하였고, 선정된 용매 ethanol을 이용하여 홍삼박 농도별 추출을 수행하였다. 산성다당체 추출 수율(11.95%) 및 양(11.8 mg/mL) 을 비교한 결과 홍삼박 용액 농도, 10%(w/v)를 최적 농도로 선정을 하였다. 이온교한수지를 이용하여 추출된 조산성다당체로부터 가장 높은 항산화 특성을 보여주는 산성다당체는 증류수로 용출 된 다당체이다. 계속해서 구조분석 결과 C-O, C-O-O-, 및 C-H 결합들과 anomeric C-6의 피크가 나타났고 C-1과 C-6의 피크들이 동일한 강도를 나타내는 것으로 보아 (1→6) glycosidic 결합이 존재함을 보여주어 전형적인 산성다당체의 특성 보여주었다.

PURPOSES : The objective of this study is to develop a methodology to estimate the minimum required separation distance (MRSD) between a vehicle and a bicycle when overtaking.METHODS: Three steps have been conducted to develop a methodology to estimate MSRD. First, a literature review has been conducted on the measurement of MSRD, and how it may be applied in Korea. Second, two assumptions have been made to develop a methodology to estimate the MSRD. The first assumption is that the maximum separation distance between a vehicle and a bicycle can be observed when they are at the same location longitudinally. In addition, it is assumed that the separation distance is invalid when the contra-flow exists. Finally, three cameras were installed at a height of 10 m to record the vehicle-bicycle interaction. Moreover, the vehicle trajectories as well as the separation distance were coded and analyzed. Through the hypothesis test and the interval estimation, the sample mean was tested and the confidence interval was estimated.RESULTS : 141 records of separation distance data were collected, and the hypothesis test demonstrated that the MSRD in Korea is significantly higher than other countries. In addition, the confidence interval of the population mean of MSRD is from 1.51 m to 1.65 m with 95% level of confidence.CONCLUSIONS: It is expected that the proposed methodology to estimate MSRD would be beneficial in studying road safety of vehicles and bicycles. Also, the proposed MSRD is expected to be designated in the act of road and transportation.

This study was performed to investigate the understanding and recognition status on separation anxiety in dogs. Most breeders(95% of the survey respondents) knew about separation anxiety in dogs, but they often neglected their dogs with no treatment and no taking care of them. Symptoms of separation anxiety are mental anxiety conditions, such as severely barking, disturbing house littered, defecation mistake and self-injury. Breeders may suffer the hardships with their dogs having separation anxiety. So the efforts are needed to reduce the occurrence of separation anxiety, and it is desirable for patients to seek animal behavior counseling, behavioral correction training, and medication therapy.

Rapid, simple, and sensitive detection of pathogen bacteria is a highly topical research area due to increasingly concerning of food safety and public health. Surface-enhanced Raman spectroscopy (SERS) is a promising and attractive technique offering fast, sensitive, comparatively low-cost, and in-suit detection of pathogenic bacteria. However, this technique requires the preparation step for reducing the noise derived from heterogeneous matrixes of food sample. Immunomagnetic separation (IMS) is widely used technique enabling separation and concentration of the target analyte. It can be used not only laboratory scale but also field diagnosis easily. Here, we synthesized gold-shelled starch magnetic microparticles (GS@SMMPs) for effective separation and concentration of Escherichia coli O157:H7, which were subsequently subjected to SERS integrated with gold-coated 3D-well substrate for bacterial detection in aqueous solution. GS@SMMPs were labelled by Anti-E. coli O157 monoclonal antibody through gold binding protein and staphylococcal protein G (GBP-SPG) fusion protein. In IMS experiment, the immuno-GS@SMMPs showed high capture efficiency over 90% to E. coli O157:H7, which resulted in 10 times decrease in detection limit in PCR assay. Through SERS assay, E. coli O157:H7 concentrated by immuno-GS@SMMPs were successfully detected even at an extremely low concentration of 101 CFU/ml the subjected to SERS. Moreover, by using sandwich method using SERS reporter consisting of GBP-SPG, we found that E. coli O157:H7 were able to be detected by SERS quantitatively through measuring the SERS intensity of GBP-SPG. This novel strategy combining SERS and IMS could be meaningful for extending the application in SERS for in-suit sensitive detection of pathogenic bacteria.

Blended membranes of hydrophilic polymers poly (vinyl alcohol) (PVA) and poly(vinyl amine) (PVAm) were prepared and crosslinked with glutaraldehyde. The characterization of membranes were done by using FTIR, XRD, DSC, SEM and swelling study. MB1.5 membrane was the best one in all since it exhibited higher separation index. By using blend membrane (MB1.5), the flux through a 65-mm film increased from 0.01 to 0.47 kg/m2h at an acetonitrile/water feed ratio between 20/80 and 5/95 w/w at 30°C while separation factor increased from the 5055 to 100.84 attributed to the higher hydrophilicity of blend membranes. On comparison of pervaporation data with water-acetonitrile vapor-liquid equilibrium data it was observed that the membrane acted as third phase to effectively break the azeotropes.

Carbon membranes can be applied to several process steps in natural gas, biogas or flue gas treatment. The significant more expensive inorganic membranes must have a higher separation performance compared to the polymeric membranes. Because of its resistance to solvents, pressure and temperature inorganic membranes have a chance in the marketplace. The predominant transport mechanism is molecular sieving (MSCM). Graphitic carbon do have lattice plane distances in the range of small gas molecules. Different steps in the production process allowed controlling the size of pores. High separation factors in gas mixtures were achieved. Reproducibility in the fabrication process is an unsolved problems. Carbon membranes showed a robust performance also in presence of impurities like H2O and H2S.

이산화탄소를 이용한 메탄올 합성반응과정에서 생성되는 물, 메탄올, 부탄올로 이루어진 혼합용액에서 제올라이트 분리막을 이용하여 물을 분리시키기 위해 투과증발실험을 진행하였다. 투과증발실험에서 사용된 분리막은 ㈜파인텍에서 합성된 제올라이트 분리막을 공급받아 사용하였다. 투과증발실험에서는 물을 분리하는 성능을 확인하기 위해 가스크로마토그래피 등의 실험장비와 성능지표 를 나타내는 계산식들을 사용하였다. 실험을 통해 물과 메탄올(분리계수 최대 250 이상), 물과 부탄올(분리계수 최대 1500 이상)의 혼합물에서 선택적으로 물 을 분리하는 것을 확인하였다. GMS (Generalized Maxwell Stefan) 이론을 적용 하여 2성분계의 투과증발 거동을 모사하였으며, 상수추정(parameter estimation) 을 통하여 제올라이트 비지지체의 흡착상수 및 확산상수를 구하였다.

Recently, Graphene Oxide (GO) has extensively studied as a membrane material due to its 2D structure and high CO2 sorption property, however, GO membrane still has challenging issues; low gas permeability to apply to practical system and low stability under dry condition. In this study, we introduced GO as a nanofiller in CO2-philic polymer matrix because GO has molecular sieving property and 2D structure. First, we mixed two kinds of PEO-containing polymers by controlling the ratio of free volume in polymer networks to increase the permeability, and then, we added GO in the mixed polymer matrix for improving the CO2/N2 selectivity. Finally, we fabricated GO-incorporated mixed matrix membranes with high CO2/N2 separation performance beyond the upper bound. High long-term stability and high CO2/N2 selectivity were also achieved in mixed gas system.

수소는 고부가가치의 신재생 수송원료이자 탄소자원화 화학제품 제조의 기초 원료로 사용할 수 있으며 이를 위해 경제성 있는 분리소재 및 분리공정기술이 중요하다. 본 연구에서는 철강부생가스 COG내 수소를 회수할 수 있는 건습식 방사법에 의한 비대칭 구조의 폴리이미드 중공사막의 제조를 연구하였다. 이를 위해 지환족 다이안하이드를 사용한 유기용매에 대한 용해성이 높은 폴리이미드 소재를 합성하여 수소, 메탄, 질소, 산소 등의 기체투과특성을 확인하였고 그 중 가장 수소 선택성이 높은 DOCDA-ODA를 이용하여 용해성 폴리이미드를 합 성하였다. 합성된 폴리이미드는 H-NMR, FT-IR을 통하여 합성이 성공적으로 이루어진 것을 확인하였으며 확보된 폴리이미드를 이용해 건습식 방사법에 의한 중공사막을 제조하였다.

This study is aimed to separation propylene and propane using membrane process. Membrane-based gas separation enables a chemical process to be low-energy consuming, if high olefin selective membrane is developed. In this study, facilitated transport membrane (FTM) is used for propylene/ propane separation. We prepared FTM module using PVP/AgBF4/TCNQ composite membrane on top of hollow fiber membrane. We developed simulation program predicting the membrane separation properties under operation conditions. Separation properties of FTM module for propylene and propane were obtained from the simulation program based on the pure gas permeation data. Based on the these results, it is predicted that an one-stage membrane process provides 99.5% of propylene at permeate side from a binary gas mixture of 95 vol% C3H6/5 vol% C3H8 supplied as a feed gas.

프로필렌은 석유화학제품의 기초 연료이며, Naphatha Cracker 에서 나오는 프로필렌/프로판 혼합물을 저온증류하여 생산된다. 저온증류를 이용하여 프로 필렌/프로판을 분리할 경우 많은 에너지가 소비되기 때문에 플랜트 규모가 작고 에너지 소비가 적은 막분리법이 대체법으로 연구되고 있다. 본 연구에서는 올레핀/파라핀 분리에 우수한 성능을 가지는 아민계 고분자를 이용하여 촉진수 송막을 제조하였으며, 이들의 프로필렌/프로판 분리특성을 알아보았다. 순수가 스 테스트를 통해 압력변화에 따른 투과도와 선택도를 구하였으며, 혼합가스 테 스트를 통해 stage-cut에 따른 투과측 프로필렌 농도 및 회수율 변화를 알아보 았다. 그 결과, 2bar, 25°C에서 95%의 프로필렌을 99.6%까지 농축 시킬 수 있음을 확인하였다.

Pebax 의 hard amide block 은 우수한 기계적 특성과 선택도를 제공하고 soft ether block 은 높은 투과도를 제공한다. 특히 ether block 은 CO2 의 투과도를 촉진시킨다. 또한 Pebax 기준으로 PEGDA 를 첨가하였을 때 첨가되는 PEGDA 분자량이 증가함에 따라 CO2/N2 선택도가 증가하는 것으로 알려졌다. 본 연구에서는 Pebax-2533 / PEGDA 혼합 막과 PES 지지체를 사용한 Pebax-2533 / PEGDA / PES 복합 막을 제조하여 비교한다. 제조된 막의 특성은 FT-IR, TGA, DSC, SEM 분석으로 확인하였으며 막의 CO2, N2 기체에 대한 투과도와 선택도 또한 확인하였다.

기존의 육상 및 근해에서의 석유 생산량은 점차 감소하는 추세로 심해에서 석유 및 가스 생산량이 증가하고 있는 추세이다. 심해용 해상 생산 설비가 필수적이나 육상에 비해 설치비용이 2배이상 들어가기 때문에 설치면적당 가스처리량이 높은 기체분리막이 주목 받고 있는 상황이다. 현재 외산 분리막이 중용되고 있으며, 이를 대체할 국산화 제품 개발이 필요한 실정이다. 따라서 본 연구에서는 폴리이미드계 고분자인 폴리에테르이미드 고분자를 사용하여 기체분리 막을 제조 하였으며, 투과도와 선택도를 높이기 위해 코팅제로 polyether black amide (PEBAX)를 사용하여 이산화탄소/메탄의 분리 정제 효율을 증가시키기 위한 연구를 진행하였다.

We present a facile, room temperature synthesis of poly(ethylenealt- maleic anhydride)-graft-poly(propylene glycol) (PEMA-g-PPG) graft copolymer-based CO2/N2 gas separation membrane with 100% conversion reaction without any further purification process. As confirmed by the Fourier transform infrared (FT-IR) and nuclear magnetic resonance (1H NMR) spectroscopy, the PEMA-g-PPG was successfully synthesized with 100% conversion of PEMA and PPG monomers. It was confirmed that the PEMA-g-PPG was amorphous and rubbery state according to the X-ray diffraction (XRD) and differential scanning calorimetry (DSC0 results. Therefore, PEMA-g-PPG/polysufulfone composite membrane exhibited high performance of CO2 permeability (99.1 Barrer) and selectivity (82.6 for CO2/N2 and 26.8 for CO2/CH4), surpassing conventional PEBAX block copolymer membrane.

본 연구에서는 올레핀/파라핀 분리용 NaY 제올라이트 분리막을 제조하기 위해서 알루미나 지지체 표면에 종결정을 진공여과법으로 코팅한 후 NaY 수열용 액을 이용하여 90°C-110°C에서 16-24시간 동안 이차성장 시켰다. 이때 올레핀 과 π-결합을 형성하는 Ag+ 이온을 NaY 결정 구조내에 포함된 Na+ 이온과 이 온교환시킴으로써 올레핀/파라핀 선택도와 안정성을 향상시키고자 하였다. 이온 교환된 NaY 제올라이트 분리막의 올레핀/파라핀 분리성능은 C3H6/C3H8= 90/10의 혼합기체를 이용하여 분석한 결과, 700 GPU의 투과도와 1.13의 선택도를 나타내었다. 낮은 선택도는 제조된 분리막에 비제올라이트 기공이 존재하기 때문으로 판단되었으며 향후 비제올라이트기공을 억제하기 위한 연구를 진행할 계획이다.

A ZIF-8 membrane was prepared via counter diffusion method. To control the diffusion rate, two supports with different pore structure were employed, conventional and modified α-Al2O3 disc; disc A and disc B. The ZIF-8 membranes are derived their name from the supports; ZIF-8-A and ZIF-8-B. While ZIF-8-A was grown at the surface of the disc A, ZIF-8-B was grown inside the disc B. At 200°C, ZIF-8-A and -B exhibited H2/CO2 separation factor (SF) of 6.69 and 8.21. In long-term thermal stability tests, both ZIF-8-A and -B were withstood their properties at 200 and 250°C for 72 h. At 300°C, SF of ZIF-8-A fell after ~2 h, however, that of ZIF-8-B dropped after ~10 h. To sum up these features, ZIF-8-B showed higher H2 selectivity and thermal stability than ZIF-8-A, since ZIF-8 membrane was synthesized inside of the support.