Abstract: In this work we have studied the electro-optical effect of two types of ferronematic nanoparticles. The first sample doped with magnetic material Fe3O4 and the second sample doped with a ferroelectric material SbSI. The difference in the two types of material that has been vaccinated led to different values of electro-optic properties because of the different susceptibility of materials. We have noticed that the material SbSI was more responsive to the applied electric field due to the nature of the constituent material (electric material) than the Fe3O4 ferromagnetic. The response time for the material SbSI is less than the response time of the ferromagnetic Fe3O4, that led to make the material SbSI best in the optical switch applications.
Abstract: Functionalized Multi-Walled Carbon Nanotubes (MWCNTs-OH) network with thickness 4μm was made by the vacuum filtration from suspension (FFS) method. The morphology, structure and optical properties of the MWCNTs film were characterized by SEM and UV-Vis. spectra techniques. The SEM images reflected highly ordered network in the form of ropes or bundles with close-packing which looks like spaghetti. The absorbance spectrum revealed that the network has a good absorbance in the UV-Vis. region. The gas sensor system was used to test the MWCNT-OH network to detect NH3 gas at room temperature. The resistance of the sensor was increased when exposed to the NH3 gas. The sensitivities of the network were 1.3% at 14ppm, 3.3% at 27ppm and 6.13% at 68ppm. The sensor is specifically sensitive to NH3 gas and does not affect by the amount of ambient air.
Abstract: Hybrid metal matrix composites are being widely investigated for use in light weight, high strength applications. In the present study, Aluminium alloy Al7075 was reinforced with B4C and TiO2 at 4% and 2% weight fractions respectively. The powders of the reinforcements were ball milled for uniform distribution in the Al matrix, and later fabricated by stir casting technique primarily due to simplicity and economy of the method. The specimen were prepared as per ASTM standards and later subjected to hardness, double shear, wear and impact tests and the results were compared with that of pure aluminium specimen fabricated by the same method. The hardness, shear strength, impact strength of the composite were found to be higher than pure aluminium by 4.97%, 32.28% ands 6.41% respectively.
Abstract: Today we are facing a great problem due to the synthetic compounds, as most of them are not environmentally friendly. Natural fibers are the fibers which are obtained from the nature and these fibers are environment friendly. So the use of natural fiber is increasing day by day in different sectors. But natural fiber has some limitations for widely use, one of them is the hydrophilic nature. So it cannot be widely used. That is why we need to incorporate them with low mechanical property synthetic compounds, widely known as composite materials. When we are using natural fiber with polymeric materials by forming composites, the fiber properties greatly influence the strength or mechanical properties. So researchers are trying to reduce this weakness of the natural fiber reinforced composite materials. One of the widely used methods for the improvement of tensile properties is the application of radiation (gamma and UV). The control use of gamma and UV-radiation increases the tensile properties in some extent for the use of materials in practical applications. The reason of this increment in tensile properties is the high energy radiation making crosslink among the molecules. In all the respect of fiber reinforced composite highest tensile properties are observed at a certain dose of gamma and UV-radiation.
Abstract: The thermal properties such the coefficient thermal expansion, α (CTE) of fused borosilicate syntactic foam was determined using dimensional changes of a temperature gradient plot. The CTE was measured and found to be achieved the value lower than the vinyl ester resin matrix when mixing with different weight percentages of the glass microballoon ranging from 2 wt.% to 10 wt.% using a thermomechanical analyzer (TMA). These results showed that it has a strong relationship with the syntactic foam physical properties such density, radius ration,cavity porosity and matrix porosity. Experimental results showed that the CTE decreases when glass microballoons are added into the composites measured at different temperatures ranging from 30 °C to 70 °C. The CTE from the experimental results were also analysed using Turner’s modification model for composites for its suitability for thermal expansion of syntactic foams.
Abstract: Concrete is the most undisputable material being used in infrastructure development throughout the world. Natural sand is a prime material used for the preparation of concrete. Nowadays river erosion and other environmental issues have led to the scarcity of river sand. The reduction in the sources of natural sand and in the cost of concrete production has resulted in the increased need to find new alternative materials to replace river sand, so that excess river erosion is prevented and high strength concrete is obtained at lower cost. The aim of the study is to minimizes the cost and achieve sustainable development of concrete pavement. Cement, sand and aggregate are basic needs but the new alternative materials that is used foundry sand which is generated by metal casting industry and in the tiles industry, about 15%-30% production goes as waste, these are partially replaced by river sand. The fine aggregate has been replaced by used foundry sand accordingly in the range of 10%, 20%, 30%, 40% & 50% by weight and also same for tiles dust for M-20 grade concrete. Concrete mixtures are produced to make (6 in × 6 in × 6 in) cube for compressive strength test at 7, 14, 28 days and (4 in × 4 in × 20 in) beam for flexural strength test at 28 days curing period, tested and compared in terms of compressive and flexural strength with the conventional concrete. Maximum compressive and flexural strength are found for 20% replacement of used foundry sand (FA2) and for 10% replacement of tiles dust (TA1) with respect to the conventional concrete (A0). By using alternative materials, the strength of concrete was increased significantly and for showing cost effectiveness a concrete pavement from Talaimari MOR to Kalpona Cinema Hall was designed for 4500 commercial vehicles per day. The pavement thickness required for conventional concrete is 28 cm whereas the pavement thickness required for concrete FA2 and TA1 are 22 cm and 24 cm respectively. Since the thickness of pavement slab is reduced, the cost of pavement construction is reduced almost 22% and 15% for concrete FA2 and concrete TA1 respectively.