Carbon fiber and its composites are increasingly used in many fields including defence, military, and allied industries. Also, surface quality is given due importance, as mating parts are used in machineries for their functioning. In this work, the turning process is considered for Carbon Fiber Reinforced Polymer (CFRP) composites by varying three important cutting variables: cutting speed, feed, and depth of cut. Correspondingly, the surface roughness is measured after the completion of turning operation. As well, a prediction model is created using different fuzzy logic membership function and Levenberg–Marquardt algorithm (LMA) in artificial intelligence. Later, the surface roughness values from the developed models are compared against the experimental values for its correlation and effectiveness in using different membership functions of fuzzy logic and ANN. Thus, the experimental results are analyzed using the effect graphs and it is presented in detail.

One-step hydrothermal reduction method was used to prepare three-dimensional carbon fiber brush-based graphene–platinum (CFB/Pt–G) composites to improve the electrocatalytic oxygen reduction activity of cathode materials for seawater oxygen-dissolved battery. Characterization results show that the reduced graphene oxide of as-prepared graphene–platinum composite displays the few-layer folded structure. In addition, Pt nanoparticles with the polycrystalline structure dispplay a preferential growth along the crystal plane of (111) and are mainly distributed around the defect cavities of folded graphene. Electrochemical results show that the diffusion-limited current density of CFB/Pt–G composite tested with 1600 rpm/min in 3.5% NaCl solution reaches 5 mA/cm2, while that of CFB/G is only 2.64 mA/cm2. Battery discharge results show that the maximum volume power density of CFB/Pt–G–Mg battery with a stable open voltage of 1.73 V is 81 times as much as the commercial seawater battery SWB1200.

Polyacrylonitrile (PAN)-based carbon fibers (CFs) and their composites, CF-reinforced plastics, have garnered significant interest as promising structural materials owing to their excellent properties and lightweight. Therefore, various processing technologies for fabricating these advanced materials using thermal energy have been intensively investigated and developed. In most cases, these thermal energy-based processes (heat treatment) are energy and time consuming due to the inefficient energy transfer from the source to materials. Meanwhile, advanced processing technologies that directly transfer energy to materials, such as radiation processing, have been developed and applied in several industrial sectors since the 1960s. Herein, general aspects of radiation processing and several key parameters for electron-beam (e-beam) processing are introduced, followed by a review of our previous studies pertaining to the preparation of low-cost CFs using specific and textile-grade PAN fibers and improvements in the mechanical and thermal properties of CF-reinforced thermoplastics afforded by e-beam irradiation. Radiation processing using e-beam irradiation is anticipated to be a promising method for fabricating advanced carbon materials and their composites.

Fibrous supercapacitors (FSs), owing to their high power density, good safety characteristic, and high flexibility, have recently been in the spotlight as energy storage devices for wearable electronics. However, despite these advantages, FCs face many challenges related to their active material of carbon fiber (CF). CF has low surface area and poor wettability between electrode and electrolyte, which result in low capacitance and poor long-term stability at high current densities. To overcome these limits, fibrous supercapacitors made using surface-activated CF (FS-SACF) are here suggested; these materials have improved specific surface area and better wettability, obtained by introducing porous structure and oxygen-containing functional groups on the CF surface, respectively, through surface engineering. The FS-SACF shows an improved ion diffusion coefficient and better electrochemical performance, including high specific capacity of 223.6 mF cm2 at current density of 10 μA cm2, high-rate performance of 171.2 mF cm2 at current density of 50.0 μA cm2, and remarkable, ultrafast cycling stability (96.2 % after 1,000 cycles at current density of 250.0 μA cm2). The excellent electrochemical performance is definitely due to the effects of surface functionalization on CF, leading to improved specific surface area and superior ion diffusion capability.

This study was carried out to investigate the proper wattage and installation distance for the efficient use of nano-carbon fiber infrared heating lamp (NCFIHL), a heating device advantageous for heating energy saving, when the production of watermelon plug seedlings in the plug seedling nursery in winter season. Six small beds were divided into plastic film, and 700 W and 900 W nano-carbon fiber infrared heating lamps were installed at 100 cm above the bed. 1 lamp at central (control), 60 cm interval (2 lamps), and 40 cm interval (3 lamps) heating lamps were installed in each bed inside the greenhouse. All treatments, except the control, were set to keep the night air temperature at 20℃ after lighting the NCFIHL. The leaf temperature showed a tendency to increase fast as the install distance was narrow. The leaf length and leaf width tended to increase as the installation distance of the 700 W heating lamp was narrow. The compactness was high in 700 W heating lamp with 40 cm of installation distance. Therefore, in consideration of maintaining the set temperature at night, installing 700 W electric lamps at 40 cm was an efficient power and installation distance for watermelon grafted seedlings considering economic feasibility.

본 연구에서는 비용매 유도 상분리법을 이용하여 폴리에테르이미드 계열의 중공사형 분리막을 제조하였다. 제조 된 중공사막의 모폴로지 조절을 위해 첨가제로는 THF, Ethanol, LiNO3를 사용하였다. 또한 높은 수소분리막의 개발을 위해 모폴로지와 기체투과성능을 특성평가를 통해 방사조건을 최적화하였다. 그 결과 THF의 함량이 증가할수록 수소/이산화탄소 선택도가 증가하였다. 하지만 trade-off 관계로 인하여 투과율은 감소하였다. Ethanol을 첨가하였을 때는 finger-like 구조를 나타냈고, LINO3를 첨가하였을 때 Sponge 구조를 보였다. 특히, PDMS 코팅층을 최적화한 중공사막의 경우, 투과율은 40 GPU, 수소/이산화탄소 선택도는 5.6을 나타냈다.

이 연구는 바잘트 섬유시트로 전단보강한 철근콘크리트 보의 전단경간비에 따른 구조물의 구조적 거동을 실험을 통해 확인하였다. 철근콘크리트 보의 전단보강은 무보강, 45도, 90도, U형보강을 변수로 두었으며 전단경간비에 따른 실험결과 U형으로 보강하였을 때 철근콘크리트 보의 전단보강효과가 높음을 확인하였다.

Cu matrix composites reinforced with chopped carbon fiber (CF), which is cost effective and can be well dispersed, are fabricated using electroless plating and hot pressing, and the effects of content and alignment of CF on the thermal properties of CF/Cu composites are studied. Thermal conductivity of CF/Cu composite increases with CF content in the in-plane direction, but it decreases above 10% CF; this is due to reduction of thermal diffusivity related with phonon scattering by agglomeration of CF. The coefficient of thermal expansion decreases in the in-plane direction and increases in the through-plane direction as the CF content increases. This is because the coefficient of thermal expansion of the long axis of CF is smaller than that of the Cu matrix, and the coefficient of thermal expansion of its short axis is larger than that of the Cu matrix. The thermal conductivity is greatly influenced by the agglomeration of CF in the CF/Cu composite, whereas the coefficient of thermal expansion is more influenced by the alignment of CF than the aggregation of CF.