NOPR Collection:

Continuous carbon nanotube-polycarbonate composite fibers through melt spinning

Fri, 01 Aug 2014 00:00:00 GMT

Title: Continuous carbon nanotube-polycarbonate composite fibers through melt spinning Authors: Das, Soma; Saha, Mitali; Sarkar, Sabyasachi Abstract: Among the many potential applications of carbon nanotubes (CNT), its usage to strengthen polymers has been paid considerable attention due to the exceptional stiffness, excellent strength and the low density. This has provided numerous opportunities for the invention of new material systems for applications requiring high strength and high modulus. In this paper, composite fibers of polycarbonate (PC) and multiwall carbon nanotubes (MWNTs) are prepared in dimethyl formamide (DMF) using melt mixing-coagulation technique followed by melt spinning at 220°C. The spinning of the coagulated PC-MWNTs is done at various draw ratios and the resultant fibers are studied by optical microscope, SEM and AFM. The mechanical properties of the composite fiber are determined and it is found that the addition of 1-1.5 wt% of MWNT increased the tensile strength of the polymer fiber from 900 MPa to 1890 MPa and Young’s modulus from 1372 MPa to 2060 MPa. The results show that the mixing of MWNT with the polycarbonate matrix, above its melting point followed by coagulation in water might have developed a strong interfacial bonding between functionalized MWNTs and PC. Page(s): 477-481

Development of sustainable construction material using construction and demolition waste

Fri, 01 Aug 2014 00:00:00 GMT

Title: Development of sustainable construction material using construction and demolition waste Authors: Dakwale, V A; Ralegaonkar, R V Abstract: Construction and demolition of old structures generates large quantity of masonry waste in urban areas. This waste is generally diverted towards landfill. In the present study, a sustainable construction material (brick) using construction and demolition (C&D) waste is developed. Cement and fly ash are used as binder and C&D waste is used as fine and coarse aggregates.
Construction and demolition waste bricks (eco-bricks) of size 230 mm × 90 mm × 90 mm are developed for the six different compositions (BR90-1 to BR90-6). Physico-mechanical tests (block density, compressive strength and water absorption) are carried out as per Indian standards and embodied energy for the considered compositions is estimated. The test results are compared to commercially available fly ash bricks. The eco-bricks that achieved the least embodied energy is considered as the best combination of sustainable construction material. Amongst the various trials carried out the brick BR90-6 with the ratio of binder, fine aggregate and coarse aggregate as 1:2.75:2.25 exhibit compressive strength and water absorption within the limits of Indian standards with minimum self weight and embodied energy. The developed sustainable product can be practically implemented over any specific location by the manufacturer which serves the purpose of solid waste management. Page(s): 451-457

Investigation of complex modulus of asphalt mastic by artificial neural networks

Fri, 01 Aug 2014 00:00:00 GMT

Title: Investigation of complex modulus of asphalt mastic by artificial neural networks Authors: Yan, Kezhen; You, Lingyun Abstract: This study investigates the complex modulus of asphalt mastic by using artiﬁcial neural networks (ANNs). The complex modulus of asphalt mastic samples are determined by using dynamic shear rheometer (DSR). Seven ﬁller-asphalt ratios (F/A) are considered in this study: 0.0, 0.4, 0.6, 0.9, 1.2, 1.5, 1.8 by the weight of asphalt binder. In ANN model, the asphalt mastic temperature, frequency and F/A are the parameters for the input layer where as the complex modulus is the parameter for the output layer. The variants of the algorithm, such as the Levenberg-Marquardt (LM), scaled conjugate gradient (SCG) and Pola-Ribiere conjugate gradient (CGP) algorithms are used in this study. A tangent sigmoid transfer function is used for both hidden layer and the output layer. The statistical indicators, such as the root-mean squared error (RMSE), the coefficient of multiple determination (R²) and the coefficient of variation (COV) are utilized to compare the predicted and measured values for model validation. Results indicate that the LM algorithm appears to be the most optimal topology. It is also demonstrated that neural networks is an excellent method that can reduce the time consumed and can be used as an important tool in evaluating complex modulus of asphalt mastic. Page(s): 445-450

A comparative study on engine performance and emissions of biodiesel and JP-8 aviation fuel in a direct injection diesel engine

Fri, 01 Aug 2014 00:00:00 GMT

Title: A comparative study on engine performance and emissions of biodiesel and JP-8 aviation fuel in a direct injection diesel engine Authors: Yamik, Hasan; Solmaz, Hamit; İçingür, Yakup Abstract: Biodiesel is one of the most important renewable energy sources for diesel engines. Studies have been carried out on different kinds of renewable fuels such as raw vegetable oil, waste cooking oil and biodiesels derived from various vegetable oils. In addition research on biodiesel has gained momentum in recent years because of the increasing environmental issues caused by fossil fuels and depletion of oil reserves. However, problems such as high viscosity, low lower heating value and increase in NO_x emissions due to oxygen content are limiting the scope of biodiesel application. JP-8 is a kerosene-based aviation fuel. JP-8 is a strategically important fuel due to properties such as lower cold filter plugging point and high lower heating value. There are some application problems on existing internal combustion engines because of the low cetane number of JP-8. In this study, diesel, sunflower methyl ester and JP-8 fuel blends are tested in a direct injection diesel engine and the possibility of the use of biodiesel and JP-8 together is investigated. As a result of tests carried out at full load conditions, engine performance and exhaust emissions are compared with those for diesel fuel. By using 25% JP-8 and 75% sunflower methyl ester, engine torque decreased by 3% and brake specific fuel consumption increased by 3.9%. Although it has been ascertained that the NO_x emissions increased, smoke emissions decreased. As a result it has been determined that biodiesel and JP-8 can be used together. Page(s): 438-444