Recently, researches on light weight of vehicles have been actively carried out to reduce fuel consumption. Researchers have generally attempted to replace metal materials with composites, but these materials do not meet the required strength and rigidity of the vehicle and require a variety of design approaches. In this paper, deck assembly of truck was compared and compared with assembly using existing floor as Apitong, and it was verified by structural analysis and modal analysis. To do this, we measured the mechanical properties of the material through tests and evaluated the safety of the Deck Assembly through maximum equivalent stress, total deformation, and safety factor values. In addition, the fit of the hybrid deck assembly structure was evaluated by measuring the approximation of the analysis by single component assembly test.

In the present study, we develop a conductive copper/carbon nanomaterial additive and investigate the effects of the morphologies of the carbon nanomaterials on the conductivities of composites containing the additive. The conductive additive is prepared by mechanically milling copper powder with carbon nanomaterials, namely, multi-walled carbon nanotubes (MWCNTs) and/or few-layer graphene (FLG). During the milling process, the carbon nanomaterials are partially embedded in the surfaces of the copper powder, such that electrically conductive pathways are formed when the powder is used in an epoxy-based composite. The conductivities of the composites increase with the volume of the carbon nanomaterial. For a constant volume of carbon nanomaterial, the FLG is observed to provide more conducting pathways than the MWCNTs, although the optimum conductivity is obtained when a mixture of FLG and MWCNTs is used.

This investigates the microstructure and mechanical properties of Al hybrid material prepared by electromagnetic duo-casting to determine the effect of heat treatment. The hybrid material is composed of an Al-Mg-Si alloy, pure Al and the interface between the Al-Mg-Si alloy and pure Al. It is heat-treated at 373, 573 and 773K for 1h and T6 treated (solution treatment at 773K for 1h and aging at 433K for 5h). As the temperature increases, the grain size of the Al-Mg-Si alloy in the hybrid material increases. The grain size of the T6 treated Al-Mg-Si alloy is similar to that of one heat-treated at 773K for 1h. The interface region where the micro-hardness becomes large from the pure Al to the Al-Mg-Si alloy widens with an increasing heat temperature. The hybrid material with a macro-interface parallel to the tensile direction experiences increased tensile strength, 0.2% proof stress and the decreased elongation after T6 heat treatment. On the other hand, in the vertical direction to the tensile direction, there is no great difference with heat treatment. The bending strength of the hybrid material with a long macro-interface to the bending direction is higher than that with a short macro-interface, which is improved by heat treatment. The hybrid material with a long macro-interface to the bending direction is fractured by cracking through the eutectic structure in the Al-Mg-Si alloy. However, in the hybrid material with a short macro-interface, the bending deformation is observed only in the limited pure Al.

최근 우수한 유연성과 화학적 안정성 등을 가진 고분자 수지와 우수한 기계적 성질 등을 나타내는 무기 재료로 이루어진 나노 복합 시스템으로써 유-무기 하이브리드 코팅 필름에 관한 연구가 활발히 진행되고 있다. 아크릴레이트 단량체로써 사용된 o-phenylphenoxyethyl acrylate (OPPEA)는 1.576의 높은 굴절률을 나타내고, Bisphenol A ethoxylate diacrylate (BAEDA)는 굴절률은 낮지만 경화된 고분자의 경도를 향상시킨다. 또한, 무기 소재로써 사용된 지르코니아는 산화지르코늄으로써 우수한 내구성과 광학특성 등을 나타낸다. 본 연구에서는 광학 특성을 향상시키기 위한 목적으로 아크릴레이트 단량체 중 BAEDA의 함량을 조절하여 필름을 제조한 뒤 연필 경도계와 아베굴절계를 이용하여 광학 특성 변화를 확인하였고, UV-vis spectrophotometer을 이용해 투과도를 비교하여 최적의 조건을 확립하였다. 그리고 실란 커플링제인 γ-methacryloxypropyltrimethoxysilane (MPS)를 사용하여 지르코니아를 소수화 처리하여 아크릴레이트 단량체에 대한 분산성을 향상시키고, 개질 전후의 물에 대한 분산성 변화를 조사하여 물에 대한 친화력이 감소하였음을 확인하였고, FT-IR ATR spectrophotometer를 통해 MPS에 의해 도입된 1716 cm-1에서의 에스터 C=O 결합 peak의 존재를 통해 MPS에 의한 지르코니아 표면의 개질 반응이 진행되었음을 확인하였다. 또한, 지르코니아의 표면에 도입된 규소 원자의 존재는 X 선 형광법을 이용하여 확인하였다. 그리고 화학적으로 개질된 지르코니아를 아크릴레이트 단량체에 도입하여 광경화 필름을 제조하였을 때, 굴절률은 아크릴레이트 자체 필름보다 1.2% 향상되었음을 확인하였고, SEM/EDS mapping 분석을 통해 PET 필름에 코팅된 개질 후 지르코니아가 아크릴레이트 코팅층에 균일하게 분포되어 있음을 알 수 있었다.

A base isolation system is widely used to reduce seismic responses of low-rise buildings. This system cannot be effectively applied to high-rise buildings because the initial stiffness of the high-rise building with the base isolation system maintains almost the same as the building without the base isolation system to set the yield shear force of the base isolation system larger than the design wind load. To solve this problem, the mid-story isolation system was proposed and applied to many buildings. The mid-story isolation system has two major objectives; first to reduce peak story drift and second to reduce peak drift of the isolation story. Usually, these two objectives are in conflict. In this study, a hybrid mid-story isolation system for a tall building is proposed. A MR (magnetorheological) damper was used to develop the hybrid mid-story isolation system. An existing building with mid-story isolation system, that is “Shiodome Sumitomo Building” a high rise building having a large atrium in the lower levels, was used for control performance evaluation of the hybrid mid-story isolation system. Fuzzy logic controller and genetic algorithm were used to develop the control algorithm for the hybrid mid-story isolation system. It can be seen from analytical results that the hybrid mid-story isolation system can provide better control performance than the ordinary mid-story isolation system and the design process developed in this study is useful for preliminary design of the hybrid mid-story isolation system for a tall building.

A conductive additive is prepared by dispersing multi-walled carbon nanotubes (MWCNTs) on Cu powder by mechanical milling and is distributed in epoxy to enhance its electrical conductivity. During milling, the MWCNTs are dispersed and partially embedded on the surface of the Cu powder to provide electrically conductive pathways within the epoxy-based composite. The degree of dispersion of the MWCNTs is controlled by varying the milling medium and the milling time. The MWCNTs are found to be more homogeneously dispersed when solvents (particularly, non-polar solvent, i.e., NMP) are used. MWCNTs gradually disperse on the surface of Cu powder because of the plastic deformation of the ductile Cu powder. However, long-time milling is found to destroy the molecular structure of MWCNTs, instead of effectively dispersing the MWCNTs more uniformly. Thus, the epoxy composite film fabricated in this study exhibits a higher electrical conductivity than 1.1 S/cm.

SWRO-PRO hybrid desalination technology is recently getting more attention especially in large desalination markets such as USA, Middle East, Japan, Singapore, etc. because of its promising potential to recover a considerable amount of osmotic energy from brine (a high-concentration solution of salt, 60,000 – 80,000 mg/L) and also to minimize the impact of the discharged brine into a marine ecosystem. By the research and development of the core technologies of the SWRO-PRO desalination system in a national desalination research project (Global MVP) supported by Ministry of Land, Infrastructure, and Transport (MOLIT) and Korea Agency for Infrastructure Technology Advancement (KAIA), it is anticipated that around 25% of total energy consumption rate (generally 3 to 4 kWh/m3) of the SWRO desalination can be reduced by recovering the brine’s osmotic energy utilizing wastewater treatment effluent as a PRO feed solution and an isobaric pressure exchanger (PX, ERI) as a PRO energy converter. However, there are still several challenges needed to be overcome in order to ultimately commercialize the novel SWRO-PRO process. They include system optimization and integration, development of efficient PRO membrane and module, development of PRO membrane fouling control technology, development of design and operation technology for the system scaling-up, development of diverse business models, and so on. In this paper, the current status and progress of the pilot study of the newly developed SWRO-PRO hybrid desalination technology is discussed.

In the present work, a comparative study of the mechanical behavior of two series of elastomeric composites, based on carboxylated styrene butadiene rubber (X-SBR) and reinforced with rice bran carbon (RBC) and graphite, is reported. Hybrid composites of X-SBR filled with RBC-graphite were also investigated in terms of the cure characteristics, hardness, tensile properties, abrasion resistance, and swelling. It was observed that the cure times decreased with the incorporation of a carbon filler whereas the torque difference, tensile strength, tensile modulus, hardness, and swelling resistance increased compared to the neat X-SBR revealing a favorable characteristic of crosslinking. Dynamic rheological analysis showed that the G' values of the composites, upon the addition of RBC-graphite, were changed to some extent. This demonstrates that the presence of a strongly developed network of fillers will ensure a reinforcing characteristic in a polymer matrix.

Public transportation companies often classify customers into only two classes, i.e. first and second class. This segmentation largely ignores travelers’ needs and may leave heterogeneity within classes. Using a discrete choice experiment, this work investigates if the introduction of dedicated sections based on travelers’ characteristics can provide them additional value.

We examined whether hybrid consumers exist in the commodity food market by comparing food products in general, fresh pork and precooked pork patties using an online questionnaire (N=200). The same consumers changed their selection criteria depending on the type of commodity food product they were considering, reflecting hybrid consumer attitudes.

This paper presents experimental results for evaluating bond strength of FRP Hybrid Bars(HYB). In order to confirm the bond strength of HYB, direct bond strength tests were performed on 20 specimens. 20 specimens made of deformed steel bars were also tested for relative comparison. HYB and deformed steel bars were embedded in a concrete block with a size of 200 mm and different attachment lengths were applied depending on the diameter of the reinforcing bars. During the test, load and relative displacement(slip) were measured and the load-displacement behaviors of all specimens were analyzed from the measured results. The maximum bond strength of deformed steel bars were higher than that of HYB regardless of its diameter. However, after the maximum load, the deformed steel bars were more dominant than the HYB in the sudden load reduction tendency.

The ultimate goal of this development is a hybrid solar energy storage device. It supplies stable power to the load due to the emergency generator that compensates for the power shortage due to solar power generation. We have developed a stand-alone photovoltaic power generation and energy storage system with a dual inverter that extends the performance life of the PV system. It solves the problem of shortening the lifespan of battery due to repetition of charge / discharge of PV system and supplies stable power to load due to emergency generator that compensates for power shortage due to solar power generation, and furthermore, A stand-alone photovoltaic power generation system having a dual inverter for extending the life span and a control method thereof. We have also developed an optimized energy solution that enables us to save and use the remaining surplus power in the ESS to save energy through efficiency, optimization and substantial energy savings.

본 총설은 다양한 저널 게재 논문으로부터 분리막 및 광촉매의 혼성 정수/하수 처리 공정을 요약하였다. 이 총설에는 (1) 분리막 광촉매 반응기(membrane photoreactor, MPR), (2) 분리막 결합 광촉매 공정에서 막오염 관리, (3) 유기 오염 물의 분해를 위한 광촉매 분리막 반응기, (4) 정수처리용 막분리 공정과 광촉매 분해의 결합, (5) 휴믹산 분해를 위한 광촉매 및 세라믹 막여과의 혼성공정, (6) 활성슬러지 여과를 위한 한외여과의 막오염에 이산화티타늄 나노입자의 영향, (7) 정수처 리용 광촉매 및 정밀여과의 혼성시스템, (8) 선박 평형수 처리용 한외여과 및 광촉매의 혼성공정 및 (9) 분리막 및 광촉매 코팅 프로필렌 구의 혼성수처리 공정이 포함되어 있다.