Synthesis and Characterization of Carbon Nanofiber with Reinforced Polymer Resin Matrix Composite

Polymer composite with reinforced fiber is a remarkable development in the field of engineering materials. The applications of composite materials have significantly increased in Defense, Aeronautical and Automobiles because of its specific modulus and high strength characteristics. In composite material development, nano particles reinforcement and nano fiber reinforcement are the most recent methods developed. In this research electrospun carbon nanofiber reinforced mat with polymer epoxy resin composites was prepared. X-ray diffraction, scanning electron microscope and ultrasonic scanning were used to study the morphology and the defect on the specimens for analyzing the structural conditions of the samples for determining the mechanical properties. The result clearly indicates that the Carbon Nanofiber (CNF)/ Polyvinyl Alcohol (PVA) mat improves the flexural strength of the epoxy resin and that 0.015% CNF in PVA gives a better mechanical strength.

Synthesis of Few-Layer Graphene on Copper Using a Low-Cost Atmospheric Thermal Chemical Vapour Deposition System with Methane and Forming Gas

Graphene has attracted wide interest across a range of applications due to its electrical, mechanical and optical properties. The use of a low-cost, table-top chemical vapour deposition system to deposit few-layer graphene onto copper is reported in this work. Characterisation of the graphene is performed using Raman spectroscopy and atomic force microscopy. The results show that few-layer graphene can be deposited at 1000 °C using CH4 as a carbon precursor, and 5% H2, 95% N2 forming gas as a diluent. The effects of deposition temperature, deposition time, and forming gas addition on graphene film quality was studied experimentally. An increase in graphene quality was observed when forming gas was added during deposition.

Study of Mechanical Properties on Bi-Directional E-Glass Fiber with Epoxy Resin Multi Walled CNT Nanoсomposite

Now a days composite material plays an important role in many industrial applications due to their excellent mechanical properties. Presently researchers are making composite materials using various filler materials to characterize the wear behavior of the composite which is used as a machine component in various industrial applications and in machine house hold articles for daily use to highly sophisticated applications. This is due to the proven fact that composite materials acquire higher strength to weight ratio. In this investigation Nano composites of E-Glass fiber/Multi walled carbon nano tube were prepared by the technique of hand layup. The glass fiber used for current investigation is E-glass fiber bi-directional of 45 degree orientation. The composite material samples were prepared in the form of a plate with a thickness of 4 mm. The fabricated composite materials were cut into analogous profiles as per ASTM for tensile and flexural testing analysis. This investigation reveals that the growth of Multi Walled Carbon Nano Tube (MWCNT) particles improves considerably the mechanical properties even if the fabrication is done by manual method like the technique of hand layup.

Synthesis and Characterization of SiNW-MnO2 Core-Shell Structure

A simple and low temperature approach has been used for the deposition of manganese oxide (MnO2) film and nanoparticles on silicon nanowires (SiNWs). Firstly, SiNWs were grown using hot wire chemical vapour process (HWCVP) technique via Vapor-Liquid-Solid (VLS) mechanism using Sn as a catalyst and then electrophoretic deposition method (EPD) was used to deposit MnO2 on them. Since SiNWs have good electron transportation and high aspect ratio, the role of SiNWs is thus for improving the electrical conduction and the surface area for MnO2 for its application in a desired form. First the deposition parameters were optimized on a transparent conductive oxide (TCO) coated glass substrate to control the thickness of the MnO2 film and then it was synthesized on SiNWs. The deposition of MnO2 has been confirmed by FEG-SEM and EDX. This structure of MnO2-SiNWs could be useful for various applications.

Experimental Analysis on Vapour Compression Refrigeration System Using Nanolubricant with HFC-134a Refrigerant

This paper investigates the reliability and performance of a refrigeration system using nanolubricant with 1, 1, 1, 2-Tetrafluoroethane (HFC-134a) refrigerant. Mineral Oil (MO) is mixed with nanoparticles such as Titanium Dioxide (TiO2) and Aluminium Oxide (Al2O3). These mixtures were used as the lubricant instead of Polyolester (POE) oil in the HFC-134a refrigeration system as HFC-134a does not compatible with raw mineral oil. An investigation was done on compatibility of mineral oil and nanoparticles mixture at 0.1 and 0.2 grams / litre with HFC-134a refrigerant. To carry out this investigation, an experimental setup was designed and fabricated in the lab. The refrigeration system performance with the nanolubricant was investigated by using energy consumption test. The results indicate that HFC-134a and mineral oil with above mentioned nanoparticles works normally and safely in the refrigeration system. The refrigeration system performance was better than the HFC-134a and POE oil system. Thus nanolubricant (Mixture of Mineral Oil (MO) and nanoParticles) can be used in refrigeration system to considerably reduce energy consumption and better Coefficient of Performance (COP).

Excitonic Quasimolecules in Quasi-Zero-Dimensional Nanosystems

The possibility of occurrence of the excitonic quasimolecule formed of spatially separated electrons and holes in a nanosystem that consists of CuO quantum dots synthesized in a silicate glass matrix. It is shown that the major contribution to the excitonic quasimolecule binding energy is made by the energy of the exchange interaction of electrons with holes and this contribution is much more substantial than the contribution of the energy of Coulomb interaction between the electrons and holes.

Thiolated Carbon Nanotubes/CdSe Quantum Dot Based Hybrid Solar Cells with Improved Long-Term Stability

In this work, the development of room-temperature solution-processed hybrid solar cells based on carbon nanotubes (CNT) - CdSe quantum dot (QD) hybrid material incorporated into a layer of conjugated polymer poly [2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta [2,1-b;3,4-b′] dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)], PCPDTBT, has been demonstrated. Incorporation of multi walled CNTs helps to improve the long-term efficiency of the solar cells in respect of power conversion efficiency (PCE) and short-circuit current density (Jsc) compared to QD only based devices. For the formation of the hybrid material hexadecylamine (HDA)/ trioctylphosphine oxide (TOPO) capped CdSe QDs were attached to CNTs by engineering the interface between CNTs and CdSe QDs by introducing thiol functional groups to CNTs. Initial PCE values of about 1.9 % under AM1.5G illumination have been achieved for this hybrid CNT-CdSe photovoltaic device. Furthermore, the long term stability of the photovoltaic performance of the devices was investigated and found superior to CdSe QD only based devices. About 90 % of the original PCE remained after storage in a glove box for almost one year without any further encapsulation. It is assumed that the improvement is mainly due to the thiol-functionalization of the CNT interface leading to a strong binding of CdSe QDs and a resulting preservation of the nanomorphology of the hybrid film over time.

Microstructure-Property Correlations of Multifunctional Si-Fe Nanocomposite

Multifunctional Si-Fe nanocomposites with varying atom percent of Fe were prepared by the high energy ball milling technique. Presence of pristine Fe and Si as separate entities in the nanocomposites was confirmed through the analyses of their Mössbauer spectrum and, x-ray diffraction patterns. The average grain size of Si has been found to be 40nm and the superparamagnetic Fe particles in the nanocomposite systems has been found to increase with increase in milling time. Transmission electron microscopic images revealed discontinuous distribution of Fe in the Si matrix. The Si-Fe nanocomposites exhibit both magnetic and photoluminescence properties at room temperature. The photoluminescence intensity was found to decrease with increase in Fe content in the nanocomposite samples, however, saturation magnetization and retentivity increases. Thus it is imperative that by adjusting the composition of Si-Fe nanocomposites their properties can be tailored to suit the desired requirements for applications in electronic devices.

Investigations on Microwave Assisted Synthesis and Characterization of Bi2WO6 Nanoparticles

Bismuth tungstate (Bi2WO6) nanoparticles were synthesized by microwave assisted method. The prepared nanoparticles were investigated by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), UV-visible spectroscopy and dielectric studies. The formation of Bi2WO6nanoparticles was confirmed by X-ray diffraction (XRD). The morphology of Bi2WO6nanoparticle was characterized using scanning electron microscopy SEM. The optical properties were studied by the UV-Visible absorption spectrum. The dielectric properties of Bi2WO6nanoparticles were studied. The activation energy was calculated from AC conductivity studies.Key words: Bi2WO6nanoparticles, XRD, SEM, TEM, UV analysis, Dielectric studies and AC conductivity studies

Polydisperse Low Diameter ‘Non-Toxic’ Silver Nanoparticles Encapsulated by Rooibos Tea Templates

This work reports the synthesis of ‘non-toxic’ polydisperse, low diameter silver nanoparticles (AgNPs). Rooibos extracts at temperatures 25 °C, 30 °C, 50 °C, 70 °C and 90 °C were used. The effect of different extraction temperature on the % yield and nature of the AgNPs were investigated. The characteristics of the ‘green synthesis’ processed AgNPs were evaluated through UV-Vis spectroscopy, high resolution tunnelling microscopy (HRTEM), X-ray diffraction (XRD) and EDX techniques. Results indicated an increase in extraction temperature leads to more polyphenol extraction, increase in the AgNP % yield and greater absorbance. A yellow to brown to dark brown colour change observed during the synthesis indicated AgNPs formation. UV-Vis results indicated the AgNPs surface plasmon peaks at 440, 447, 450, 460 and 489 nm for the 25 °C, 30 °C, 50 °C, 70 °C, 90 °C respectively. SEM results revealed spherical nanosized particles with dense cores and lighter outer region with mean diameters for AgNPs ranged between 4.4-5.8 nm. EDX results indicated prominent Ag peaks at 3.10 keV. XRD results showed vaguely defined amorphous polyol peaks at below 2θ = 27°. The sharp peaks at 2θ = 38°, 45°, 66° and 77° which were assigned as 111, 200, 220 and 321 corresponded to the face-centred cubic crystalline silver phase.