• Steel and Composite Structures
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• v.31 no.4
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• pp.419-426
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• 2019

In this paper, buckling analyses of composite plate reinforced by Graphen platelate (GPL) is studied. The Halphin-Tsai model is used for obtaining the effective material properties of nano composite plate. The nano composite plate is modeled by Third order shear deformation theory (TSDT). The elastic medium is simulated by Winkler model. Employing nonlinear strains-displacements, stress-strain, the energy equations of plate are obtained and using Hamilton's principal, the governing equations are derived. The governing equations are solved based on Navier method. The effect of GPL volume percent, geometrical parameters of plate and elastic foundation on the buckling load are investigated. Results showed that with increasing GPLs volume percent, the buckling load increases.

• Steel and Composite Structures
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• v.41 no.6
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• pp.775-785
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• 2021

Analysis of nonlinear stability behaviors of composite magneto-electro-elastic (MEE) nano-scale shells have been represented in this reaserch. The shell is assumed to be under a transverse mechanical load. Composite MEE material has been produced form piezoelectric and magnetic ingradients in which the material charactristics may be varied according to the percentages of the ingradients. The governing equations including scale effects have been developed in the framework of nonlocal elasticity. It has been demonstrated that nonlinear stability behaviors of MEE nano-sized shells in electrical-magnetic fields rely on the percentages of the ingradients. Also, the efficacy of nonlocality parameter, magnetic intensities and electrical voltages on stability loads of the nanoshells have been researched.

• The magazine of the Korean Society for Advanced Composite Structures
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• v.6 no.4
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• pp.11-18
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• 2015

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.912-912
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• 2006

• Journal of Powder Materials
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• v.8 no.3
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• pp.210-213
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• 2001

$Si_3N_4$/TiN nano/nano-type composites were successfully fabricated by the combination of a mechano-chemical grinding (MCG) method and a short time sintering process, and their wear resistance was evaluated. Powder mixtures of $\alpha-Si_3N_4$and Ti were prepared using mechano-chemical grinding process and the resulting nanocomposite powder mixtures were consolidated using pulsed electric current sintering (PECS). TEM observation showed that the nano/nano-type composites consisted of homogeneous and very fine matrix grains with the size less than 100 nm. The obtained $Si_3N_4$-based nano/nano-type showed high wear resistance and electric discharge machinability.

• Journal of the Microelectronics and Packaging Society
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• v.19 no.4
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• pp.65-69
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• 2012

Composite coating can be manufactured during the electroplating with the bath containing a suspension of particles: ceramic, polymer, nanopowders. Improvement of hardness, wear resistance, corrosion resistance and lubrication properties are well-known advantage of composite coating. In this study, nano $TiO_2$ powder dispersed Ni composite plating was investigated. The improvement of surface hardness and photo decomposition effects can be expected in this coating. Zeta potential was measured with pH. The effect of ultrasonication time and types of ultrasonicator were studied to minimize the agglomeration of $TiO_2$ nanopowders in the electrolyte. Optimum conditions for nano $TiO_2$ dispersed Ni composite coating were $40mA/cm^2$ of current density, pH 3.5, and $50^{\circ}C$. At these conditions, $TiO_2$ nanoparticles contents in the Ni deposit was 15-20 at.%.

• Design & Manufacturing
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• v.10 no.3
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• pp.14-19
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• 2016

Thermally or electrically conductive filler reinforced polymer composites are extensively being developed as the demand for light weight material increases rapidly in industiral applications need good conductivity such as heat sink of the electronics or light. Carbon or ceramic materials like graphite, carbon nanotube or boron nitride are typical conductive fillers with good thermal or electical conductivity. Using these conductive fillers, the polymer composites in the market show wide range of thermal conductivity from approximately 1 W/mK to 20 W/mK, which is quite enhanced considering the thermal conductivity lower than 0.5 W/mK for most polymeric materials. The practical use of these composites, however, is yet limited to specific applications because most composites are still not conductive enough or too difficult to process, too brittle, too expensive for higher conductivity. For practical use of conductive composite, the thermal conductivity required depending on the heat releasing mode are studied first for simplified unit cooling geometry to propose thermal conductivities of the composites for reasonable cooling performance comparing with the metal heat sink as a reference. Also, as a practical design for heat sink based on polymer composite, composite and metal sheet hybrid structures are investigated for LED lamp heat sink and audio amplication module housing to find that this hybrid structure can be a good solution considering all of the cooling performance, manufacturing, mechanical performance, cost and weight.

• Journal of the Korean Electrochemical Society
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• v.8 no.2
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• pp.77-81
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• 2005

Porous-composite electrodes have been developed using silica gel, which reduce carbon aerogel usage with high cost. Silica gel powder was added to the carbon aerogel to simplify the manufacturing procedure and to increase the wet-ability, the mechanical strength and the CDI efficiency. Porous composite electrodes composed of carbon aerogel and silica gel powder were prepared by paste rolling method. Carbon aerosol composite electrodes with $10\times10cm^2$ are placed face to face between spacers, and assembled the four-stage series cells for CDI process. Each stage is composed of 45 cells. Four-stage series cells (flow through cells) for CDI process are put in continuous-system reactor containing 1,000ml-NaCl solution bath of 1,000 ppm. The four-stage series cells with carbon aerogel electrodes are charged at 1.2V and are discharged at 0.001V, and then read the current. Conclusively, removal efficiencies of ions using the four-stage series cells composed of carbon aerogel composite electrodes show good removal efficiency of $99\%$ respectively.

• Advances in nano research
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• v.8 no.1
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• pp.59-68
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• 2020

In the present study, buckling analysis of sandwich composite (carbon nanotube reinforced composite and fiber reinforced composite) Euler-Bernoulli beam in two configurations (core and layers material), three laminates (combination of different angles) and two models (relative thickness of core according to peripheral layers) using differential quadrature method (DQM) is studied. Also, the effects of porosity coefficient and different types of porosity distribution on critical buckling load are discussed. Using sandwich beam, it shows a considerable enhancement in the critical buckling load when compared to ordinary composite. Actually, resistance against buckling in sandwich beam is between two to four times more. It is also showed the critical buckling loads of laminate 1 and 3 are significantly larger than the results of laminate 2. When Configuration 2 is used, the critical buckling load rises about 3 percent in laminate 1 and 3 compared to the results of configuration 1. The amount of enhancement for laminate 3 is about 17 percent. It is also demonstrated that the influence of the core height (thickness) in the case of lower carbon volume fractions is ignorable. Even though, when volume fraction of fiber increases, differences grow smoothly. It should be noticed the amount of decline has inverse relationship with the beam aspect ratio. Among three porosity patterns investigated, beam with the distribution of porosity Type 2 (downward parabolic) has the maximum critical buckling load. At the end, the first three modes of buckling will be demonstrated to investigate the effect of spring constants.

• Korean Journal of Materials Research
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• v.33 no.4
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• pp.151-158
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• 2023

In this study, a new type of composite material combined with carbonyl iron, a relatively strong ferromagnetic material, was prepared to overcome the current application limitations of Prussian blue, which is effective in removing radioactive cesium. The surface of the prepared composite was analyzed using SEM and XRD, and it was confirmed that nano-sized Prussian Blue was synthesized on the particle surface. In order to evaluate the cesium removal ability, 0.2 g of the composite prepared for raw cesium aquatic solution at a concentration of 5 ㎍ was added and reacted, resulting in a cesium removal rate of 99.5 %. The complex follows Langmuir's adsorption model and has a maximum adsorption amount (q_e) of 79.3 mg/g. The Central Composite Design (CCD) of the Response Surface Method (RSM) was used to derive the optimal application conditions of the prepared composite. The optimal application conditions achieved using Response optimization appeared at a stirring speed of pH 7, 17.6 RPM. The composite manufactured through this research is a material that overcomes the Prussian Blue limit in powder form and is considered to be excellent economically and environmentally when applied to a cesium removal site.