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Magnesium AZ91/AlN-based surface composites have been synthesized using the friction stir processing (FSP) technique. The influence of particle addition during FSP on microstructural and mechanical properties has been investigated. Composite plates of 5, 10, and 15 vol. % AlN were synthesized using two-pass FSP with an axial force of 10 KN, a tool travel speed of 40 mm/min, and a tool rotation speed of 1200 rpm. The AZ91/AlN surface composites were analyzed microscopically with the use of an optical microscope, an x-ray diffractometer, and a scanning electron microscope. The prepared composites were tested for hardness and tensile strength. Micrographs taken in the stir zone revealed a consistent distribution of AlN particles throughout the AZ91 matrix. The AZ91/AlN surface composites were tested for hardness and tensile strength, and the findings showed that the AlN particles improved the mechanical properties without significantly decreasing ductility. The fracture surfaces of the composites were studied, and the mechanisms of fracture were identified. [ABSTRACT FROM AUTHOR]

The present study is an integrated approach of experimental and simulation processes to investigate the influences of the flushing on the wear, textural feature, heat dissipation, tool-tip temperature, and elemental contents of the electrical discharge machining-tool. The general heat transfer equation in cylindrical coordinates is used to explain the thermal phenomenon through the tool, where the boundary conditions are influenced by convective interactions and dimensionless numbers. The inter-electrode flushing is considered a micro-channel flow, and the used model is conceptualized from "Hazen–Poiseuille observation." It is observed that the adopted model has a prediction error of 8.503% and can accurately explain the thermal consequences of the process. The study reveals that tool wear is influenced by flushing velocity and flushing pressure. The tool-tip temperature reduces with the Reynolds number, and effectual expelling of the debris can be ensued with a flushing of a higher Reynolds number (Re). However, the increment of Re beyond 4500 provides rapid heat dissipation, which produces extensive residual stress and creates cracks on the surface. [ABSTRACT FROM AUTHOR]

Nariocrystalline CdS impregnated cellulose nanocrystals (CdS-Cellulose) were embedded in polyvinylidene fluoride (PVDF) matrix and free-standing flexible films of CdS-cellulose/PVDF nanocomposite were made by sol-gel technique. Effect of CdS loadings in cellulose embedded in the host matrix (PVDF) on the impedance properties was studied critically for the above samples. Dielectric constants were studied as a function of frequencies (1-100 kHz) at room temperatures. The dielectric constant increased significantly in CdS-cellulose/PVDF nanocomposite than that for pristine PVDF film. The higher values of dielectric constant as well as dielectric loss were obtained at lower frequencies. This may be caused due to contributions arising out of space charge, dipole, and electronic polarizations. At higher frequencies, only dipole and electronic polarization were seen to contribute significantly. The nature of the Cole-Cole plots could be seen to deviate significantly from one impedance semicircular arc before diverging after a frequency of 3,158, 2,147, and 1,925 Hz for CdS-cellulose/PVDF nanocomposite with increased loading of CdS. POLYM. ENG. SCI., 58:1419-1427, 2018. [C] 2017 Society of Plastics Engineers, INTRODUCTION Cellulose nanocrystals (CNCs) have received much attention as renewable, biodegradable, nontoxic, low cost nano materials with some remarkable properties. These include large surface to volume ratio, high tensile strength, [...]

This study is the first attempt to assess the presence of 16 priority polycyclic aromatic hydrocarbons (PAHs) enlisted by the US Environmental Protection Agency in PM2.5 and PM10 from industrial areas of Odisha State, India. During 2017–2018, bimonthly sampling of PM10 and PM2.5 was carried out for 24 h in the industrial and mining areas of Jharsuguda and Angul in Odisha during the pre-monsoon, monsoon, and post monsoon seasons. Highest mean concentration of ∑16PAHs in PM2.5 was observed during the post monsoon (170 ng/m3) period followed by pre-monsoon (48 ng/m3) and monsoon (16 ng/m 3) periods, respectively. A similar trend of ∑16PAHs was also observed in PM10 with higher levels observed during post monsoon (286 ng/m3) followed by pre-monsoon (81 ng/m3) and monsoon (27 ng/m3) seasons. Diagnostic ratios and principal component analysis suggested diesel, gasoline and coal combustion as the major contributors of atmospheric PAH pollution in Odisha. Back trajectory analysis revealed that PAH concentration was affected majorly by air masses originating from the northwest direction traversing through central India. Toxic equivalents ranged between 0.24 and 94.13 ng TEQ/m3. In our study, the incremental lifetime cancer risk ranged between 10–5 and 10–3, representing potential cancer risk. [ABSTRACT FROM AUTHOR]

The alternative dielectrics like vegetable oils, emulsions, and different organic solutions have captured the emerging research attentions, and few pieces of literature also discussed about their potentiality to replace conventional kerosene. However, observations of the existing literatures are limited up to the assessment of the primary responses like material removal rate (MRR), surface roughness (SR), hardness, etc., which are not sufficient to recommend them as a suitable one. Therefore, the present work intends to incorporate a little bit value-addition to the existing research by including their impacts on the crater-overlapping, debris-agglomeration, surface integrity, and recast-layer thickness of the EDM-surface. Here, the machining is performed on the titanium alloy 'Ti6Al4V' using a cylindrical copper tool with various flushing pressures, and the obtained outcomes are compared with that of conventional kerosene. Findings claim the presence of spikes, black spots, and discrete thermal defects with comparatively thinner recast thickness when bio-dielectric was used. Moreover, comparatively 20.75% higher MRR, 16.68% less SR, and 18.75% more tool wear rate (TWR) are noticed for bio-dielectric within the permissible range of the flushing pressure, but beyond this range, 4–6.5% reduction in MRR and 26.00–31.5% increment in TWR are observed. [ABSTRACT FROM AUTHOR]

Graphene oxide/PVDF composite free‐standing flexible films were prepared with different amount of GO fillers in PVDF matrix using sol‐gel technique. The films were characterized by Field emission scanning electron microscopy, X‐ray diffraction, Fourier transform infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS) and Raman studies. Results FTIR, XPS, and Raman were critically analysed for modulation of bonding ambience. The GO/PVDF composite films indicated films to be sp2 rich. Departure from centro‐symmetry of GO when embedded in PVDF matrix leading towards efficient nanogenerator application is discussed critically in the light of Raman and XPS studies. High output voltage was recorded for the unpoled film while the poled samples indicated very negligible output. A rectifying circuit was used to charge a capacitor which was discharged for supplying energy to trigger a red light emitting diode. A maximum a.c. output voltage of ±28V was recorded at microwatt power level. Increments in output voltages with increased GO loading in the PVDF matrix were observed. POLYM. COMPOS., 39:4205–4216, 2018. © 2017 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]