Structural,thermal, mechanical and dynamic mechanical properties of cenosphere filled polypropylene composites

Polypropylene (PP)/cenosphere based composites were fabricated and characterized for their structural/morphological and mechanical properties such as tensile, flexural, impact and dynamic mechanical properties such as storage and loss moduli as a function of temperature. The morphological attributes were characterized by scanning electron microscopy (SEM) and wide-angle X-ray diffraction (WAXD) while the thermal characterizations were done by conducting differential scanning calorimetry (DSC) and thermo-gravimetric analysis (TGA). The morphological investigations have revealed a uniformly distributed/dispersed state of the cenosphere in the bulk PP matrix of the composites. The WAXD/DSC studies have revealed a decrease in crystallinity of the composites with increase in cenosphere content. Dynamic mechanical analysis (DMA) revealed an enhancement in the energy dissipation ability of the composite with 10 wt.% of cenosphere and an increase in the storage modulus up to ∼30% in the composites relative to the soft PP-phase. The tensile modulus increased up to ∼43% accompanied by a nominal decrease in tensile strength while the strain at break remained largely unaffected. The impact strength of the composites marginally reduced compared to PP indicating a low-cost material-concept with maximized stiffness–toughness combination. The theoretical modeling of the tensile data revealed appreciable extent of phase-adhesion despite the cenospheres lack any surface modification indicating better extent of mechanical interlocking and surface-compatibility between polymer and filler. Fractured surface morphology indicated that the failure mode of the composites undergoes a switch-over from matrix-controlled shear deformation to filler-controlled quasi-brittle modes above a cenosphere loading of 10 wt.% in the composites.     

Processing,characterization, and erosion wear characteristics of borosilicate glass microspheres filled epoxy composites

In spite of significant research done in the field of particulate filled polymeric composites, reports on polymers filled with glass microspheres have been extremely rare. In view of this, the present work includes the processing, characterization, and erosion wear response of a new class of epoxy composites filled with different proportions of borosilicate glass microspheres. Hand lay‐up technique is used for making these composites in a laboratory scale. Various physical and mechanical properties are evaluated under controlled laboratory conditions. It is found that while the tensile and flexural strength are marginally influenced, the impact strength is improved quite significantly. Besides, multifold enhancement in composite microhardness is also noticed. Erosion trials are made as per the experimental design based on Taguchi's L₁₆ orthogonal array. Parametric appraisal of erosion process is made and influential parameters affecting the wear rate predominantly are identified. The results indicate that erosion wear rate of these composites is influenced more significantly by impact velocity and filler content respectively compared to others factors. The eroded composite samples are studied using scanning electron microscopy and possible wear mechanisms are discussed. POLYM. COMPOS., 36:1685–1692, 2015. © 2014 Society of Plastics Engineers     

Experimental study of hydrous ethanol gasoline blend (E10) in a four stroke port fuel‐injected spark ignition engine

Performance, emissions and combustion characteristics of a port‐injected engine fuelled with hydrous ethanol gasoline blend (E10 ‐ 10% of hydrous ethanol by volume in gasoline) were compared with gasoline operation. Hydrous ethanol blend produced higher power output with lean mixtures at part throttle condition. Higher flame velocity and wider flammability limits of the blend resulted in lower cycle‐by‐cycle variations in indicated mean effective pressure as compared to gasoline. Hydro carbon emission was also lower due to the oxygen available in the fuel (E10), which enhanced the combustion rate. Higher latent heat of evaporation of the ethanol blend and water present in it resulted in lower in‐cylinder temperature, which in turn led to lesser NOx emissions. Thermal efficiency with the blend was higher in the leaner operating conditions than gasoline. Not much difference in performance, emission and combustion characteristics between neat gasoline and E10 were observed at full throttle operation. On the whole, hydrous ethanol blends can be used as a fuel with good performance and low emissions at part load condition. Copyright © 2012 John Wiley & Sons, Ltd.     

Erosive Wear Characteristics of Plasma-Sprayed Coatings of Glass Microspheres Premixed With TiO2 Particles

In this article, plasma-sprayed coatings of borosilicate glass microspheres (BGM) premixed with TiO₂ particles in different proportions are deposited at various input power levels of the plasma torch. Erosion wear characteristics of these coatings are investigated following a plan of experiments based on the Taguchi technique, which is used to acquire the erosion test data in a controlled way. The study reveals that the impact velocity is the most significant among various factors influencing the wear rate of these coatings. An artificial neural network (ANN) approach is then implemented taking into account training and testing procedures to predict the triboperformance under different erosive wear conditions. This technique helps in saving time and resources for a large number of experimental trials and successfully predicts the wear rate of the coatings both within and beyond the experimental domain. This article proposes an integrated application of ANN and Taguchi's experimental design for analyzing and predicting the solid particle erosion wear response of a new class of coatings.     

Triboperformance Analysis of Coatings of LD Slag Premixed with TiO2 Using Experimental Design and ANN

This article reports on the analysis of triboperformance in regard to the erosion wear of a new class of coatings by an integrated implementation of Taguchi's experimental design and artificial neural networks (ANNs). Plasma-sprayed coatings of LD slag premixed with TiO₂ in different weight proportions are deposited on metal substrates at various input power levels of the plasma torch. Solid particle erosion trials, as per ASTM G 76 test standards, are conducted on the coating samples following a well-planned experimental schedule based on Taguchi's design of experiments. An air jet–type erosion test rig capable of creating reproducible erosive wear situations is used. Significant process parameters predominantly influencing the rate of erosion are identified. The study reveals that the impact velocity is the most significant among various factors influencing the wear rate of these coatings. A prediction model based on an ANN is proposed to predict the erosion performance of these coatings under a wide range of erosive wear conditions. This model is based on the database obtained from the experiments and involves training, testing, and prediction protocols. This work shows that an ANN model helps to save time and resources that are required for a large number of experimental trials and successfully predicts the erosion wear rate of the coatings both within and beyond the experimental domain.     

Thermodynamic optimization of a coiled tube heat exchanger under constant wall heat flux condition

In this paper the second law analysis of thermodynamic irreversibilities in a coiled tube heat exchanger has been carried out for both laminar and turbulent flow conditions. The expression for the scaled non-dimensional entropy generation rate for such a system is derived in terms of four dimensionless parameters: Prandtl number, heat exchanger duty parameter, Dean number and coil to tube diameter ratio. It has been observed that for a particular value of Prandtl number, Dean number and duty parameter, there exists an optimum diameter ratio where the entropy generation rate is minimum. It is also found that with increase in Dean number or Reynolds number, the optimum value of the diameter ratio decreases for a particular value of Prandtl number and heat exchanger duty parameter.     

A comparative study on erosion characteristics of red mud filled bamboo–epoxy and glass–epoxy composites

Bamboo fiber reinforced epoxy matrix composites filled with different weight proportions of red mud (a solid waste generated in alumina plants) are fabricated. The mechanical properties of these composites are evaluated and are then compared with those of a similar set of glass–epoxy composites. The solid particle erosion characteristics of the bamboo–epoxy composites have been studied and the experimental results are compared with those for glass–epoxy composites under similar test conditions available in the published literature. For this, an air jet type erosion test rig and Taguchi orthogonal arrays have been used. The methodology based on Taguchi’s experimental design approach is employed to make a parametric analysis of erosion wear process. This systematic experimentation has led to determination of significant process parameters and material variables that predominantly influence the wear rate of the particulate filled composites reinforced with bamboo and glass fiber, respectively. The comparative study indicates that although the bamboo based composites exhibit relatively inferior mechanical properties, their erosion wear performance is better than that of the glass fiber reinforced composites. It further indicates that the incorporation of red mud particulates results in improvement of erosion wear resistance of both the bamboo and glass fiber composites.     

Runoff and Sediment Yield Modelling for a Treated Hilly Watershed in Eastern Himalaya Using the Water Erosion Prediction Project Model

The Water Erosion Prediction Project (WEPP) watershed model was calibrated and validated for a hilly watershed treated with graded bunding and water-harvesting tank in high rainfall condition of eastern Himalayan range in India. The performance of the model for the treated watershed was unacceptable with percent deviation of −45.81 and −38.35 respectively for runoff and sediment yield simulations when calibrated parameter values for the nearby untreated watershed were used. This was possibly due to differences in soil properties and average land slope. When soil parameters were calibrated for the treated watershed, the model performance improved remarkably. During calibration, the model simulated surface runoff and sediment yield with percent deviations equal to +6.24 and +9.02, and Nash–Sutcliffe simulation coefficients equal to 0.85 and 0.81, respectively. During validation period, the model simulated runoff and sediment yield with percent deviations equal to +8.56 and +9.36, and Nash–Sutcliffe simulation coefficients equal to 0.81 and 0.80, respectively. The model tended to slightly under-predict runoff and sediment yield of higher magnitudes. The model performance was quite sensitive to soil parameters namely, rill erodibility, interrill erodibility, hydraulic conductivity, critical shear stress and Manning’s roughness coefficient with varying levels. The WEPP model picked up the hydrology associated with bund and water-harvesting tank, and simulated runoff and sediment yield well with overall deviations within ±10% and Nash–Sutcliffe simulation coefficients >0.80. Simulation results indicate that in high slope and high rainfall conditions of eastern Himalayan region of India where vegetative measures are not adequate to restrict soil loss within the permissible limit, the WEPP model can be applied to formulate structure-based management strategies to control soil loss and to develop water resources.