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        검색결과 642

        41.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The utilization of carbonaceous reinforcement-based polymer matrix composites in structural applications has become a hot topic in composite research. Although conventional carbon fiber-reinforced polymer composites (CFRPs) have revolutionized the composite industry by offering unparalleled features, they are often plagued with a weak interface and lack of toughness. However, the promising aspects of carbon fiber-based fiber hybrid composites and hierarchical composites can compensate for these setbacks. This review provides a meticulous landscape and recent progress of polymer matrixbased different carbonaceous (carbon fiber, carbon nanotube, graphene, and nanodiamond) fillers reinforced composites’ mechanical properties. First, the mechanical performance of neat CFRP was exhaustively analyzed, attributing parameters were listed down, and CFRPs’ mechanical performance barriers were clearly outlined. Here, short carbon fiber-reinforced thermoplastic composite was distinguished as a prospective material. Second, the strategic advantages of fiber hybrid composites over conventional CFRP were elucidated. Third, the mechanical performance of hierarchical composites based on carbon nanotube (1D), graphene (2D) and nanodiamond (0D) was expounded and evaluated against neat CFRP. Fourth, the review comprehensively discussed different fabrication methods, categorized them according to performance and suggested potential future directions. From here, the review sorted out three-dimensional printing (3DP) as the most futuristic fabrication method and thoroughly delivered its pros and cons in the context of the aforementioned carbonaceous materials. To conclude, the structural applications, current challenges and future prospects pertinent to these carbonaceous fillers reinforced composite materials were elaborated.
        8,000원
        42.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Acrylonitrile–butadiene–styrene (ABS) terpolymer was compounded with short carbon fiber (CF) and carbon nanotube (CNT) using a micro-extruder followed by the injection molding process. Composite samples were fabricated with loading ratios of 20 wt.% CF and 0.1, 0.5 and 1.0 wt.% of CNT. Mechanical, electrical, thermo-mechanical, thermal, melt-flow, and structural investigations of ABS-based composites were conducted by performing tensile, impact, hardness, and wear tests, conductive atomic force microscopy (AFM), dynamic mechanical analysis (DMA), thermal gravimetric analysis (TGA), melt flow rate test (MFR), scanning electron microscopy (SEM) characterization techniques, respectively. According to mechanical test data of resultant composites including tensile and impact test findings, CNT additions led to the remarkable increase in tensile strength and impact resistance for CF reinforced ABS composites. The formation of synergy between CNT nanoparticles and CF was confirmed by electrical conduction results. The conductive path in ABS/CF composite system was achieved by the incorporation of CNT with different loading levels. SEM micrographs of composites proved that CNT nanoparticles exhibited homogeneous dispersion into ABS matrix for lower loadings.
        4,300원
        43.
        2022.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this present investigation, machinability studies on novel aluminum composite with hybrid reinforcements of copper-coated 4% carbon fibers (CFs) and 3% nanoclay in AA6026 matrix fabricated by compocasting method is performed. Step drill bit and multifaceted drill bit are used by adopting central composite design (CCD) in response surface methodology (RSM). The outcomes show that, with a rise in rotational speed surface irregularities, resultant force and material removal rate (MRR) intensifies, and with the additional rise in rotational speed, all the outputs decrease considerably. High MRR, resultant cutting force, and surface roughness are obtained with multifaceted carbide drills, compared with a step drill. Desirability function is used to maximize the MRR and minimize the resultant cutting forces considering the constant surface roughness of 3 μm. The optimal values are rotational speed of 1285 rpm, feed rate of 60 mm/min with the step drill bit, producing an MRR of 0.0439 kg/sec and a resultant cutting force of 185.818 N. The second-order empirical models are developed for outputs, which are fed into the non-traditional metaheuristic Evaporation Rate-based Water Cycle Algorithm (ER-WCA) therefore the lower objective value is achieved with step drill of 51.7421. It is found that using a step drill the machinability performance of this hybrid nanocomposite is well improved than the machining with other drill bits. This composite fulfills the norms of 2000/53/CE-ELV European environmental directives.
        5,400원
        44.
        2022.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Rapid development of carbon nanotubes (CNTs) reinforced to polymer composites has been recently noticed in many aspects. In this work, the latest developments on fatigue and fracture enhancement of polymer composites with CNTs reinforcement with diverse methods are thoroughly compiled and systematically reviewed. The existing available researches clearly demonstrate that fatigue fracture resistance of polymer composites can be improved accordingly with the addition of CNTs. However, this work identifies an interesting research gap for the first time in this field. Based on the systematic reviewing approach, it is noticed that all previously performed experiments in this field were mostly focused upon studying one factor only at a time. In addition, it is also addressed that there were no previous studies reported a relationship or effect of one factor upon others during examining the fatigue fracture of carbon nanotubes. Moreover, there was no adequate discussion demonstrating the interaction of parameters or the influence of one parameter upon another when both were examined simultaneously. It is also realized that the scope of the conducted fatigue fracture studies of carbon nanotubes were mainly focused on microscale fatigue analysis but not the macroscale one, which can consider the effect of environment and service condition. In addition, the inadequacy of fatigue life predicting models via analytical and numerical methods for CNT-reinforced polymer composites have also been highlighted. Besides, barriers and challenges for future directions on the application of CNT-reinforced polymer composite materials are also discussed here in details.
        4,600원
        45.
        2022.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This article presents recent advancements in the development of flexible piezoresistive strain sensors based on carbon nanotubes (CNTs)–polymer composites, with particular attention to their electromechanical properties. Various fabrication approaches and material preparation of CNTs–polymer composites with improved piezoresistive performance are introduced. Moreover, the article presents the working principle of the piezoresistive sensors in terms of the tunneling effect and disconnection-reconnection mechanism. The sensing performances of recently reported applications are studied. This work also reveals that the CNTs–polymer composites have great potential for flexible, skin-mountable, and wearable electronics applications. Finally, possible challenges for the future developments of CNTs–polymer composites are discussed.
        4,600원
        46.
        2022.05 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Corrosion is a natural, inevitable process, and is one of the world's most serious problems. Losses incurred due to corrosion are extremely expensive for society. Several technological strategies have been explored and implemented to address these losses. The use of inhibitors to prevent corrosion is a common and efficient method to reduce corrosion losses. This review covers Al and Al-composite corrosion inhibitors in chloride-containing solutions, because of their popularity in a broad array of industrial applications. A vast number of studies in the literature detail the common tendency of Al and Al-composites with reinforcements to deteriorate. Accordingly, it is worthwhile to employ inhibitors to protect them, as discussed in the present work. The emphasis is on selecting the smartest corrosion inhibitor and evaluating its performance. According to the study, the most commonly used corrosion inhibitors are 1,4-naphthoquinone (NQ), 1,5-naphthalene diol, 3-amino-1,2,4-triazole-5-thiol (ATAT), ammonium tetrathiotungstate, clotrimazole, amoxicillin, antimicrobial and antifungal drugs. Electrochemical impedance spectroscopy (EIS), potentiodynamic (PDP), and weight loss were among the most commonly used modern electrochemical technologies to test inhibitors’ efficacy under environmental conditions.
        4,000원
        47.
        2022.05 구독 인증기관·개인회원 무료
        In this study, for thermal neutron absorption, an aluminum metal composite in which B4C particles were uniformly dispersed was prepared using stirring casting and hot rolling processes. The microstructure, thermal neutron absorption rate, mechanical properties and dispersibility of the reinforcement of the prepared B4C/Al composite were analyzed. The composite in which the 40 μm sized B4C particles were uniformly dispersed increased the tensile strength as the volume ratio of the reinforcement increased.
        49.
        2022.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        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.
        4,500원
        50.
        2022.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        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.
        4,000원
        51.
        2022.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The current study was intended to synthesize and characterize the physical, chemical, and mechanical properties of carbon/ carbon (C/C) composites using the chemical vapor infiltration (CVI) process. To that end, carbon fiber felt (CF) was used as a preform, and methane and hydrogen were employed as reactive and carrier gases, respectively. After deciding on the optimum temperature (1050 °C), the composite samples were produced at different times (0–195 h). Then the samples were studied for their phase and microstructure characteristics using XRD, SEM, FESEM, FTIR, and Raman spectroscope. The results showed that by increasing the CVI process time up to 195 h, the density of the produced samples increased from 0.20 to 1.62 g/cm3, and the specific surface area decreased from 58.78 to 0.23 m2/ g. Also, by increasing the process duration, the deposition rate decreased due to the reduction of the available surface for carbon deposition. In other words, due to the increase in density, and decrease in both porosity and specific surface area, the thermal conductivity coefficient and the bending strength of the samples increased. The composite specimens’ SEM images of the fracture surface indicated a weak interface between the carbon fibers and the carbon layer developed by the CVI process. The structural analyses showed that the morphology of carbon growth during the CVI process was initially laminar, but changed to rough-laminar (RL) with the higher duration of the CVI process.
        4,800원
        52.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Carbon xerogels (CXs) with three-dimensional (3D) structure, unusual surface, physical, electrical and mechanical properties and their electrically conductive polymer polypyrrole (PPy) composites were synthesized as electrode materials for supercapacitors. The effect of different resorcinol/formaldehyde (R/C) ratios, whether solvent exchange with or without acetone and polypyrrole addition on the physicochemical (FTIR, XRD, BET, SEM and TGA) and electrochemical properties (CV, 1000 cycles) of the synthesized materials were investigated. It was observed that the R/C ratio and the solvent exchange process prior to drying affect the specific surface areas and the pore size distributions, thereby positively affecting the specific capacitance. PPy film thickness was observed to be effective in the specific capacitance of the electrode in PPy composite synthesis. Among the synthesized materials, the highest specific capacitance values belong to polypyrrole/carbon xerogel composites. As a result of the analysis and calculations, it was found that the highest specific capacitance belongs to CX2/PPy composite with 599 Fg− 1 at 5 mVs− 1. CX2/PPy composite has been found to have a capacitance retention rate of 80.30% at the end of 1000 cycles.
        5,800원
        53.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        위성 해수면온도 합성장은 수치예보모델의 입력 자료 및 지구온난화와 기후 변화 연구에 활용되는 중요한 자료이다. 본 연구에서는 2007년부터 2018년까지 6종류의 위성 해수면온도 합성장 자료를 수집하여 한반도 주변 해역에서 각 해수면온도 합성장 자료의 공간 분포 특성을 분석하였다. 기상청 해양기상부이 실측 수온 자료와 해수면온도 합성장 자료의 시계열을 비교하고 오차의 최대값 및 최대값이 나타나는 시기를 분석하였다. 황해 연안에 위치한 덕적도와 칠발도 부이에서 위성 해수면온도 합성장과 실측 수온의 차는 1년주기 또는 반년주기의 높은 변동성을 보였다. 포항 부이 에서는 강한 용승에 의해 냉수대가 발생한 2013년 여름철에 높은 수온 차가 나타났다. 해수면온도 자료의 시계열을 활용하여 스펙트럼 분석을 수행한 결과, 일별 위성 해수면온도 합성장은 약 1개월 이상의 주기에서는 실측 자료와 유사 한 스펙트럼 에너지를 보였다. 반면 위성 해수면온도 합성장과 실측 수온의 스펙트럼 에너지의 차는 시간 주파수가 증 가할수록 증가하는 경향을 보였다. 이는 위성 해수면온도 합성장 자료가 연안 부근 수온의 시간적 변동성을 적절하게 표현하지 못하였을 가능성을 시사한다. 위성 해수면온도 영상의 해양 전선은 공간 구조와 강도의 측면에서 위성 해수면 온도 합성장 자료 간 차이점을 보였다. 해수면온도 합성장에서 표현되는 공간 규모 또한 공간 스펙트럼 분석을 통해 조사하였다. 그 결과 고해상도 해수면온도 합성 영상이 저해상도 해수면온도 영상보다 상대적으로 중규모 해양 현상의 공간 구조를 더 잘 표현하였다. 따라서 실제 중규모 해양 현상을 보다 구체적으로 표현할 수 있는 위성 해수면온도 합성장 생산을 위한 고도의 기술 개발이 필요하다.
        4,600원
        54.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 Mori-Tanaka 방법 및 멀티스케일 접근 방법을 적용하여 CNT의 굴곡성을 고려한 CNT-복합재 보강 콘크리트 보에 대한 균열해석을 수행하였다. Ad-hoc Eshelby 텐서에 기반하여 CNT의 굴곡성을 기하학적으로 고려하여 폴리머와 합성 하는 방법을 적용하였다. 멀티스케일 방법이 기반하여 CNT 함유량 및 굴곡성 변화에 따른 복합재의 탄성계수 및 강도변화를 추정하였다. 본 해석모델은 기존 문헌과 비교검증하였다. 본 연구에서 도출한 결과는 CNT 함유량과 CNT 굴곡성의 상호관계를 도시하였다. CNT 보강 복합재 구조물의 해석에 있어서 CNT 굴곡성의 중요성을 입증하였다.
        4,000원
        57.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Because of depletion of fossil fuel from the earth curst and increase of environmental concerns, in search of an efficient alternative to the traditional carbon black (CB), a biochar known as rice husk carbon (RHC) has been examined here as a filler material to develop the EPDM composite. In this regard, the ball milled RHC was further treated with ultrasonic wave and used with or without its surface treatment by the silane coupling agent [i.e., 3-mercaptopropyl triethoxysilane (3-MPTMS)]. Among the RHC, ultrasonic treated RHC (UHC) and silane treated UHC (USHC), the EPDM composite of USHC showed nearly similar tensile strength to that of the CB (e.g., CB: 33.88 kgf/cm2, USHC: 31.38 kgf/cm2 at 20 wt% filler loading) with an enhanced elongation at break (e.g., CB: 206%, USHC: 342% at 20 wt% filler loading) and surprisingly much less compression set value (CB: 40.87%, USHC: 18.95% even after 40 wt% of filler loading). Compared to RHC, the UHC also showed its better performance next to the USHC. In addition to presence of both the carbon and silica in RHC and additional silica within the flexible aliphatic chain in USHC, the disintegration of RHC by ultrasonic treatment towards its narrow particle distribution, smaller particle size, and increased surface area is considered very much effective to develop the corresponding high performance EPDM composites. Thus, the use of waste material, i.e., rice husk through the ultrasonication of RHC followed by its surface treatment can be used as a potential filler material to prepare the environment friendly and cost effective high performing composites to be used in different efficient end products, and motivated further for industrial upscaling.
        4,000원
        58.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, Ti-Mo-EB composites are prepared by ball milling and spark plasma sintering (SPS) to obtain a low elastic modulus and high strength and to evaluate the microstructure and mechanical properties as a function of the process conditions. As the milling time and sintering temperature increased, Mo, as a β-Ti stabilizing element, diffused, and the microstructure of β-Ti increased. In addition, the size of the observed phase was small, so the modulus and hardness of α-Ti and β-Ti were measured using nanoindentation equipment. In both phases, as the milling time and sintering temperature increased, the modulus of elasticity decreased, and the hardness increased. After 12 h of milling, the specimen sintered at 1000oC showed the lowest values of modulus of elasticity of 117.52 and 101.46 GPa for α-Ti and β-Ti, respectively, confirming that the values are lower compared to the that in previously reported studies.
        4,000원
        59.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근 대규모 토목 및 건축 구조물 증가 추세로 건설 부재의 고강도 및 경량화에 대한 수요가 높아지고 있다. 기존 시멘트 경량 복합체의 경우 단위 체적 중량이 낮아 강도 저하 문제가 발생할 수 있다. 보통 경량화를 위해서 시멘트 복합체를 배합할 때 일반 경량골재와 고무재질의 경량골재, 플라스틱 펠릿 등 다양한 인공 경량골재를 적용한 시멘트 복합체로 경량화를 확보할 수 있다. 이 중에서도 시멘트 복합체의 인공 경량골재로 플라스틱을 사용하면 상대적으로 골재 자체의 강도를 확보하면서 경량화를 꾀할 수 있지만 재료의 매끄러운 표면 특성으로 인해 시멘트 페이스트와 부착하는 데 불리한 부분이 있고 이는 콘크리트 골재 또는 시멘트 복합체 골재로서의 사용에 있어 단점이 된다. 띠라서 이번 연구에서는 기존 연구에서 플라스틱 골재 로 가장 적합한 유형으로 확인된 PP, PE 두가지 유형의 플라스틱 골재와 강섬유, 양생방법을 변수로 하여 실험을 진행하였고 실험 결과 플라스틱의 비중이나 표면 재질뿐만 아니라 강섬유의 혼입유무, 양생방법에 의해서 시멘트 복합체의 물리적 특성이 변화된다는 것을 확인하였다.
        4,000원
        60.
        2021.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In recent, fiber-reinforced composites have been widely used in many fields because of their excellent performance. In order to manufacture lightweight, high-performance, and inexpensive composites various laminated structures were designed. Six types of hybrid composites were fabricated with glass/basalt/aramid fibers by VARTM process. The effect of the laminated structure on the mechanical properties of composites was investigated through impact energy, tensile and bending strength. Compared to other conditions more higher impact energy was obtained when the aramid fibers were in the center position and more higher bending strength was obtained when the fibers are laminated in the order of increasing bending performance from top to bottom. The laminate structure did not affect tensile strength which mainly depends on the property of fibers.
        4,000원
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