The investigation on the lightweight of automobiles has been underway in commercial vehicles as well as passenger cars due to global warming and strengthening of European emission standards. In this study, the V-arm were developed for lightweight parts using aluminum alloy instead of steel with high pressure die casting processing. This study has focused on lightweight adaptive concept design. Several models of V-arm were designed and analyzed for the fluidity and solidification. V-arm was produced with ADC12 by high pressure die-casting process. The mechanical properties of developed V-arm were measured; such as tensile strength, elongation, shear strength, and durability. The possibility of mass production with the light weight aluminum V-arm substitute from the steel. The weight was reduced about 38% from 16kg to 9.98kg. The productivity was improved with decreasing the process from 8 to 5 by All-in-0ne process using high pressure die-casting.

Sludge transporting pipes in wastewater treatment plant are easy to be clogged with struvite when the digested sludge and dehydrated filtrate are transported through the pipes, which lowers the efficiency of sludge treatment system in a WWTP. pH is one of the most important factors in struvite formation, and carbon dioxide separated from biogas can be used to control pH and struvite formation. By controlling pH, the amount of dehydrating agent can be reduced by about 10%, which saves the budget for facility maintenance. As CO2 is reused and dehydrating chemicals are saved, the approach can contribute to global warming gas reduction.

F-containing TiO2 nanopowders are synthesized using simple wet processes (precipitation-based and hydrothermal) from ammonium hexafluorotitanate (AHFT, (NH4)2TiF6) as a precursor to apply as a photocatalyst for the degradation of rhodamine B (RhB). The surface properties of the prepared samples are evaluated using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). The results confirm that the synthesized anatase TiO2 has sphere-like shapes, with numerous small nanoparticles containing fluorine on the surface. The photocatalytic activity of F-containing TiO2 compared with F-free TiO2 is characterized by measuring the degradation of RhB using a xenon lamp. The photocatalytic degradation of F-containing TiO2 exhibits improved photocatalytic activity, based on the positive effects of adsorbed F ions on the surface.

In the industrial fields, the process capability index has been using to evaluate the variation of quality in the process. The traditional process capability indices such as Cp, Cpk, Cpm, and C┼pm have been applied in the industrial fields. These traditional process capability indices are mainly applied in the univariate analysis. However, the main streams in the recent industry are the multivariate manufacturing process and the multiple quality characteristics are corrected each other. Therefore, the multivariate statistical method should be used in the process capability analysis. The multivariate process indices need to be enhanced with more useful information and extensive application in the recent industrial fields. Hence, the purpose of the study is to develop a more effective multivariate process index (MCpI ) using the multivariate inverted normal loss function. The multivariate inverted normal loss function has the flexibility for the any type of the symmetrical and asymmetrical loss functions as well as the economic information. Especially, the proposed modeling method for the multivariate inverted normal loss function (MINLF) and the expected loss from MINLF in this paper can be applied to the any type of the symmetrical and asymmetrical loss functions. And this modeling method can be easily expanded from a bivariate case to a multivariate case.

본 연구는 통합공정일정계획(Integrated Process Planning and Scheduling; IPPS)의 최적화를 위한 계산 효율성이 높은 탐욕적 휴리스틱과 유전알고리즘(Genetic Algorithm; GA)을 결합한 하이브리드형 유전 알고리즘을 제안한다. IPPS는 기존의 공정계획과 일정계획을 동시에 풀고자 하는 NP-Hard 문제이다. 특히, 본 연구에서 다루는 IPPS는 tool related constraints가 포함된 것으로서 전통적인 GA는 수행도중 infeasible schedule을 빈번히 발생시킨다. 제안하는 방법의 아이디어는 전체적인 schedule의 구조에 영향을 미치는 operation의 sequence와 machine의 결정은 GA의 procedure를 따르고, 목적함수의 부분계산이 가능한 tool과 Tool Access Direction(TAD)는 greedy heuristics을 통하여 infeasibility를 해소하자는 것이다. 이를 통하여 계산시간의 급격한 증가 없이 또는 기존에 비해 계산시간을 감소시키면서 좋은 품질의 해를 구할 수 있다. 본 연구에서 제안하는 알고리즘은 benchmark problems을 이용하여 성능을 평가한다.

1970년대 중반 석유 파동 이후 대체 에너지 개발에 대한 관심이 커지면서 그 중에서 혐기성 공정에서 발생하는 바이오가스 생산과 활용 기술 개발에 대한 연구가 진행되고 있다. 바이오 가스의 주성분은 50-70%CH4/30-40%CO2으로 이루어져 있고 이 때 메탄을 > 95% 순도로 농축하면 도시가스와 자동차 연료로 사용이 가능하다. 바이오가스의 정제기술로 막 분리법은 낮은 에너지 소모량, 이동성 및 쉬운 작동성 등의 장점을 가지고 있다. 본 연구에서는 바이오가스를 95% 이상의 메탄으로 농축하기 위해 폴리설폰 중공사막과 다단 분리막 공정을 이용하였다. 분리막 공정에서 압력, 온도, 막면적 등 다양한 공정 변수에서 95% 이상의 메탄 순도를 얻기 위한 연구를 진행하였다.

이온전도성 분리막을 이용한 산소 제조 기술은 효율적으로 산소를 제조할 수 있으며, 산소부화 연소기술, 순산소 연소기술 등에 적용 범위가 넓다. 고온에서 운전하는 특성상 열적, 화학적으로 안정적이어야 하며, 특히 이산화탄소 재순환기술을 적용하기 위해서는 이산화탄소 내성이 필수적이다. 본 연구에서는 높은 투과성능을 가지는 Ba0.5Sr0.5Co0.8Fe0.2O3-δ를 상전이 및 소결법으로 중공사막을 제조하였으며 표면을 페롭스카이트-플로라이트 이중상 물질로 개질하여 이산화탄소 내성을 갖도록 하였다. 제조한 분리막을 산소 분리 모듈에 적용하여 부피당 면적에 따른 투과도 및 산소 유량 변화를 관찰하였다.

본 연구에서는 이산화탄소 포집 및 물 재이용을 위한 통합 시스템으로서 정삼투 공정의 적용 가능성에 대한 평가를 수행하였다. 해당 통합 공정은 이산화탄소 배출 저감을 위해 화력발전소에 적용되고 있는 습식 이산화탄소 포집설비에 정삼투 기반 공정을 추가함으로써 이산화탄소 포집뿐만 아니라 물 재이용 및 냉각수 생산을 동시에 달성할 수 있다. CO2를 흡수한 5M의 모노에탄올아민(습식용매)을 유도용액으로 적용한 결과 40 LMH (FO mode) 및 85 LMH (PRO mode)라는 매우 높은 수투과도를 얻을 수 있었다.

본 연구에서는 시판되는 탄소전극의 제조에 활용되는 활성탄의 형태가 아닌, 활성탄소섬유를 이용하여 축전식 탈염공정에 적용할 탄소전극을 제조하였다. polyvinylidene fluoride (PVDF)를 지지체로 사용하며 활성탄소섬유를 배합한 후 시판되는 그라파이트 시트에 캐스팅하여 탄소전극을 제조한 다음 염 제거 효율을 평가하였다. 활성탄소섬유의 입자 크기를 달리하였고 용매와 고분자 지지체 그리고 활성탄소섬유를 80 : 2 : 18, 80 : 5 : 15의 배합비율로 전극을 제조하였다. 축전식 탈염공정 운전조건으로 흡착전압, 시간, 탈착전압, 시간, NaCl 공급액의 농도와 유속 등을 달리하여 제조한 활성탄소섬유전극의 성능을 평가하였다.

정삼투막(Forward osomosis, FO) 공정은 차세대 해수담수화 기술 중 하나이 다. FO 공정은 운영에너지나 막오염의 장점에도 불구하고 유도용액의 분리회수 등의 문제로 실증화 단계에 어려움이 있다. 따라서 현재 FO 공정에 대해서는 FO를 단독으로 사용하기보다 RO 전단에 FO 공정을 두어 이용하는 hybrid 시스 템으로 이용하려는 연구가 많이 진행되고 있다. 본 연구는 유도용액의 분리회수 가 필요하지 않은 FO-RO 공정에서의 성능 지표 중 하나인 투과유량을 늘리기 위해 공정 운전 조건 중 유도용액의 유량변화에 따른 성능을 평가하였다.

In this study, various physical cleaning methods such as physical washing and osmotic backwash, were conducted to understand membrane fouling properties by employing real secondary wastewater effluent (SWWE). In addition, microfiltration (MF) and ultrafiltration (UF) pretreatments were compared to maximize removal of organic matter and to control membrane fouling efficiently. Organic foulants deposited on the active layer of FO membrane were observed by fouling behavior test. The relationship between concentrations of natural organic matter and membrane fouling was also investigated from the bench-scale FO tests.

기후변화에 따른 영향으로 전 세계적으로 물부족 문제는 지속적으로 증가할 것으로 예상된다. 이러한 물부족 문제를 해결하기 위하여 다양한 대체수자원 확보기술이 개발되고 있으며, 그 중에 해수담수화 기술이 가장 활발하게 도입되고 있다. 최근 새로운 개념의 해수담수화 기술이 검토되고 있으며, 그 중 막증발법(Membrane distillation, MD) 기술이 활발하게 연구되고 있다. 국토교통부 국가연구개발사업으로 진행 중인 “Global MVP 연구단”에서는 세계 최대 규모인 400 m³/일 규모의 복합탈염 플랜트를 구축하고 있으며, 국산 중공사 막증발 모듈을 이용하여 새로운 개념의 복합탈염 설계기술과 구축기술을 확보하고자 현재 다양한 연구를 진행 중에 있다.

Membrane distillation (MD) has shown the potential to further reduce the volume of coal seam gas (CSG) reverse osmosis (RO) brine. However, despite its potential, the lack of appropriate MD membranes limits its industrial use. Therefore, this study was aimed on the fabrication of a robust membrane for the treatment of real CSG RO brine via an air gap MD (AGMD) process. Here, graphene/polyvinylidene fluoride (G/PVDF) membranes were prepared through a phase inversion method. Surface characterization revealed that all G/PVDF membranes exhibited favorable membrane properties having high porosity and liquid entry pressure, and suitable pore size. AGMD test results indicated a high water vapor flux of 20.5 L/m²h. Long-term AGMD operation revealed the robustness of G/PVDF membrane with superior performance compared to commercial PVDF membrane.

In this study, the effect of chemically enhanced backwash(CEB) coping with algal(Heterosigma Akashiwo) inflow was evaluated in the seawater desalination pretreatment process using ceramic membrane. In order to confirm the possibility of long-term filtration operation, the recovery rate of transmembrane pressure(TMP) due to the CEB using NaOCl was examined. When the membrane flow rate was 83.3 LMH, the TMP was maintained within 200 kPa for 84 hours in seawater influent. As the algal counts of 30,000 cell/mL were injected into the influent of seawater, however, the TMP rapidly increased and exceed maximum value. Membrane fouling caused by the algae was very poorly recovered by usual physical backwash. The CEB was performed for 30 min(3 min circulation / 27 min immersion) with 300 mg/L of NaOCl. As a result of the CEB application, it was possible to maintain a stable operating of filtration during 10 days and the average recovery rate of TMP by the CEB was 98.1%. It has been confirmed that the CEB using NaOCl is very effective in removal of membrane fouling by algae, resulted in stable membrane filtration for the long-term operation.

This study investigated the effect of the grinding media of a ball mill under various conditions on the raw material of copper powder during the milling process with a simulation of the discrete element method. Using the simulation of the three-dimensional motion of the grinding media in the stirred ball mill, we researched the grinding mechanism to calculate the force, kinetic energy, and medium velocity of the grinding media. The grinding behavior of the copper powder was investigated by scanning electron microscopy. We found that the particle size increased with an increasing rotation speed and milling time, and the particle morphology of the copper powder became more of a plate type. Nevertheless, the particle morphology slightly depended on the different grinding media of the ball mill. Moreover, the simulation results showed that rotation speed and ball size increased with the force and energy.

This paper seeks to present a multi-control method that can contribute to effective control of the production line with multiple bottleneck processes. The multi-control method is the production system that complements shortcomings of CONWIP and DBR, and it is designed to determine the raw material input according to the WIP level of two bottleneck processes and WIP level of total process. The effectiveness of the production system developed by applying the multi-control method was verified by the following three procedures. Raw material input conditions of the multi-control method are as follows. First, raw materials are go into the production line when the number of the total process WIP is lower than established number of WIP in total process and first process is idle. Second, raw materials are introduced when the number of WIP of two bottleneck processes is lower than the established number of WIP of each bottleneck process. Third, raw materials are introduced when the first process and in front of bottleneck process are idle even if the number of WIP in the total process is less than established number of WIP of the total process. The production line with two bottleneck processes was selected as the condition for production environment, and the production process modeling of CONWIP, DBR and multi-control production method was defined according to the production condition. And the optimum limited WIP level suitable for each system was obtained by applying a genetic algorithm to determine the total limited number of WIP of CONWIP, the limited number of WIP of DBR bottleneck process, the number of WIP in the total process of multi-control method and the limited number of WIP of bottleneck process. The limited number of WIP of CONWIP, DBR and multi-control method obtained by the genetic algorithm were applied to ARENA modeling, which is simulation software, and a simulation was conducted to derive result values on the basis of three criteria such as production volume, lead time and number of goods in-progress.

A study on the decolorization method of salt-fermented anchovy sauce using activated carbon was carried out. The anchovy sauce filtered with a diatomaceous membrane after heating at 85℃ for 20 min was reacted with 3.0% (w/w) activated carbon with pH 4.5 at 55℃ for 2 hr. The color difference value and turbidity related to the decolorizing effect showed excellent improvement results with a difference of 23% and 88%, respectively. The overall taste and color preference of decolorized anchovy sauce were significantly increased in shrimp sauce by 0.4-0.5 points (p<0.05). In order to minimize the precipitation of amino acid during storage, 1% silicon dioxide or gelatin was mixed and filtered after the activated carbon reaction. Turbidity, as index of sedimentation, was improved by 15% at 30℃ for 2 weeks. The recycle system with activated carbon coated membrane filter reduced the processing time and cost on decolorization of anchovy sauce. When the concentrated anchovy sauce was recirculated, the amount of total protein as an indicator of taste compounds was increased by 125%, which is 1.8% compared to the conventional 0.8%, indicating that it is highly useful as a liquid seasoning.