A study on mechanical behavior and damage assessment of short bamboo fiber based polymer composites

Now-a-days, natural fiber reinforced polymer composites are increasingly being used for varieties of engineering applications due to their many advantages. Among natural fibers, bamboo has been widely used for many such applications due to its availability. Since these composites are finding wide applications in highly dusty environment which are subjected to solid particle erosion, a study of their erosion characteristics are of vital importance. Generally solid particle erosion, a typical wear mode leads to material loss due to repeated impact of solid particles. For a composite material, its mechanical behavior and surface damage by solid particle erosion depends on many factors. Attempts have been made in this paper to explore the potential utilization of bamboo fiber in polymer matrix composites. Therefore, the present research is focused on the mechanical and erosion wear behavior of short bamboo fiber reinforced composites filled with Alumina (Al2O3) particulate. It further outlines a methodology based on Taguchi’s experimental design approach to make a parametric analysis of erosion characteristics. Finally, the morphology of eroded surfaces is examined using scanning electron microscopy (SEM) and possible erosion mechanisms are identified

Assessing Public Transit Accessibility and Equity of 10-County Atlanta Region using General Transit Feed Specification (GTFS) Data

From a conceptual understanding, though equity and accessibility are two fundamentally different issues but at the core, they possess an intricate relationship with each other when it comes down to the question of public transit (Talen and Anselin, 1998). Public transportation systems are usually aimed at serving two distinct groups of users ﾖ people who neither can afford a car nor have access to safe and convenient non-motorized alternatives, and people who independently choose not to drive but use public transit (Karner and Golub, 2015). Accessibility, often a debatable concern due to its widely differing reception, but continues to be at the center of contemporary transportation planning efforts. When it comes down to the provision of public transit service, it becomes even more crucial from equity concern as well. Transportation equity can be thought of as an effort to ensure that the service caters to the users irrespective of their spatial or socioeconomic background (Blanchard and et. al., 2017). Thus, it becomes more important for the captive riders who have no access to private automobile and thus no way either to travel by public transport or transit system (Langford, Fry and Higgs, 2012; Mavoa, Witten, Pearce and Day, 2009). However, due to its complexity and varying scales of recognition by various Metropolitan Planning Organizations (MPOs) and regional transportation authorities, FTA funded transportation improvement projects are being evaluated on widely varying accessibility matrices. This paper is intended to assess public transit equity by applying a spatially and temporally sound and resolved accessibility indicator suggested by Karner (2016) and demonstrate its utility with reference to 10-county Atlanta region

Process optimization and comparative analysis of EDM and EDD process in machining Al6063/10% SiC metal matrix composites

750-756In this work, a comparative investigation of electric discharge machining (EDM) and electric discharge drilling (EDD) has been presented to evaluate the performance measures for machining blind holes in Al6063/10% SiC metal matrix composites (MMCs). The work has been conducted with an aim of optimizing the material removal rate (MRR), tool wear rate (TWR), and surface roughness (SR). The input parameters chosen for machining are (i) discharged current, (ii) pulse-on time, and (iii) duty factor. The Taguchi’s L9 orthogonal array has been applied to design the experiments. The grey relational analysis has also been used to determine the optimal level of input parameters to achieve better results. Analysis of variances (ANOVA) has been applied to perform the statistical analysis of the experimental data. The results have shown that discharge current is the most influencing factor that affects the multiple performance characteristics in both EDM and EDD processes

Process optimization and comparative analysis of EDM and EDD process in machining Al6063/10% SiC metal matrix composites

In this work, a comparative investigation of electric discharge machining (EDM) and electric discharge drilling (EDD) hasbeen presented to evaluate the performance measures for machining blind holes in Al6063/10% SiC metal matrix composites(MMCs). The work has been conducted with an aim of optimizing the material removal rate (MRR), tool wear rate (TWR), andsurface roughness (SR). The input parameters chosen for machining are (i) discharged current, (ii) pulse-on time, and (iii) dutyfactor. The Taguchi’s L9 orthogonal array has been applied to design the experiments. The grey relational analysis has also beenused to determine the optimal level of input parameters to achieve better results. Analysis of variances (ANOVA) has beenapplied to perform the statistical analysis of the experimental data. The results have shown that discharge current is the mostinfluencing factor that affects the multiple performance characteristics in both EDM and EDD processes

Neural network modeling of forces in drilling of glass/epoxy composites filled with agro-based waste materials

649-658In this paper, the drilling behavior of a new class of composite materials has been experimentally investigated. The composite laminates have been manufactured using glass fibers, epoxy resin, and filler materials. The abundantly available agro-based waste materials (coconut coir, rice husk, and wheat husk) have been used as filler materials. The drilling experiments have been performed at several levels of feed (0.03 to 0.3 mm/rev.) and speed (90 to 2800 RPM) using different types of drill bits. The effect of these parameters on the drilling forces (axial thrust and torque) has been analyzed for all types of laminates under investigation. The artificial neural network-based models have also been proposed to compute the drilling forces. The fitness of the models has been measured in terms of mean percentage error between the predicted and actual values. From the investigation, it has been found that the drilling forces computed by the neural network models were quite close to the experimental values

Mechanical characterization of animal fibre-based composites

Horsehair-based composites have been prepared by reinforcing polylactic acid (PLA) using hot compression molding. The weight fraction of horsehair fibre in composites has been varied from 0% to 30 wt.% to investigate the effect of fibre loading on the mechanical properties and moisture absorption performance of the developed composites. The mechanical properties, such as strength and modulus (tensile and flexural), impact energy, and moisture absorption behaviour of the fabricated composites, are experimentally evaluated. The experimental results recommend that the composites reinforced with 20 wt.% horsehair exhibit superior mechanical properties as compared to other developed composites. The tensile strength and modulus, flexural strength and modulus, Charpy and Izod impact energy of the composites reinforced with 20 wt.% horsehair are improved by 9.52, 28.74, 7, 5.63, 398.11 and 379.31% as compared to, one-on-one, neat PLA. The findings also reveal that the percentage of moisture absorption of the developed composites increases with an increase in the fibre content in the developed composites.

Mechanical characterization of animal fibre-based composites

293-297Horsehair-based composites have been prepared by reinforcing polylactic acid (PLA) using hot compression molding. The weight fraction of horsehair fibre in composites has been varied from 0% to 30 wt.% to investigate the effect of fibre loading on the mechanical properties and moisture absorption performance of the developed composites. The mechanical properties, such as strength and modulus (tensile and flexural), impact energy, and moisture absorption behaviour of the fabricated composites, are experimentally evaluated. The experimental results recommend that the composites reinforced with 20 wt.% horsehair exhibit superior mechanical properties as compared to other developed composites. The tensile strength and modulus, flexural strength and modulus, Charpy and Izod impact energy of the composites reinforced with 20 wt.% horsehair are improved by 9.52, 28.74, 7, 5.63, 398.11 and 379.31% as compared to, one-on-one, neat PLA. The findings also reveal that the percentage of moisture absorption of the developed composites increases with an increase in the fibre content in the developed composites

Neural network modeling of forces in drilling of glass/epoxy composites filled with agro-based waste materials

In this paper, the drilling behavior of a new class of composite materials has been experimentally investigated. Thecomposite laminates have been manufactured using glass fibers, epoxy resin, and filler materials. The abundantly availableagro-based waste materials (coconut coir, rice husk, and wheat husk) have been used as filler materials. The drillingexperiments have been performed at several levels of feed (0.03 to 0.3 mm/rev.) and speed (90 to 2800 RPM) using differenttypes of drill bits. The effect of these parameters on the drilling forces (axial thrust and torque) has been analyzed for alltypes of laminates under investigation. The artificial neural network-based models have also been proposed to compute thedrilling forces. The fitness of the models has been measured in terms of mean percentage error between the predicted andactual values. From the investigation, it has been found that the drilling forces computed by the neural network models werequite close to the experimental values

A proline insertion-deletion in the spike glycoprotein fusion peptide of mouse hepatitis virus strongly alters neuropathology.

Fusion peptides (FPs) in spike proteins are key players mediating early events in cell-to-cell fusion, vital for intercellular viral spread. A proline residue located at the central FP region has often been suggested to have a distinctive role in this fusion event. The spike glycoprotein from strain RSA59 (PP) of mouse hepatitis virus (MHV) contains two central, consecutive prolines in the FP. Here, we report that deletion of one of these proline residues, resulting in RSA59 (P), significantly affected neural cell syncytia formation and viral titers postinfection in vitro. Transcranial inoculation of C57Bl/6 mice with RSA59 (PP) or RSA59 (P) yielded similar degrees of necrotizing hepatitis and meningitis, but only RSA59 (PP) produced widespread encephalitis that extended deeply into the brain parenchyma. By day 6 postinfection, both virus variants were mostly cleared from the brain. Interestingly, inoculation with the RSA59 (P)- carrying MHV significantly reduced demyelination at the chronic stage. We also found that the presence of two consecutive prolines in FP promotes a more ordered, compact, and rigid structure in the spike protein. These effects on FP structure were due to proline\u27s unique stereochemical properties intrinsic to its secondary amino acid structure, revealed by molecular dynamics andNMRexperiments.Wetherefore propose that the differences in the severity of encephalitis and demyelination between RSA59 (PP) and RSA59 (P) arise from the presence or absence, respectively, of the two consecutive prolines in FP. Our studies define a structural determinant of MHV entry in the brain parenchyma important for altered neuropathogenesis. © 2019 Singh et al. Published under exclusive license by The American Society for Biochemistry and Molecular Biology, Inc