Influence of ZrO2, SiO2, Al2 O3 and TiO2 nanoparticles on maize seed germination under different growth conditions

The focus of this investigation is to evaluate the phytotoxicity of selected metal oxide nanoparticles and microparticles as a function of maize seed germination and root elongation under different growth conditions (Petri plate, cotton and soil). The results of seed germination and root elongation experiments reveal that all the growth conditions show almost similar results. Alumina (Al₂ O₃) and titania (TiO₂) nanoparticles significantly reduce the germination percentage, whereas silica (SiO₂) nanoparticles and microparticles enhance the same. The results of nanoparticles and microparticles of zirconia (ZrO₂) are found to be same as those of controls. Root elongation is enhanced by SiO₂ nanoparticles and microparticles treatment, whereas inhibition is observed with Al₂ O₃ and TiO₂ nanoparticles and microparticles. The X‐ray fluorescence spectrometry data of the treated and control seed samples show that seeds uptake SiO₂ particles to a greater extent followed by TiO₂, Al₂ O₃ and ZrO₂. In addition, the uptake of nanoparticles is found to be greater than that of microparticles. Thus, the tested metal oxides penetrated seeds at the nanoscale as compared with the microscale. This study clarifies phytotoxicity of nanoparticles treated in different growth substrates and highlights the impact of nanoparticles on environment and agricultural systems.Inspec keywords: zirconium compounds, silicon compounds, aluminium compounds, titanium compounds, nanoparticles, nanobiotechnology, botany, toxicologyOther keywords: metal oxide nanoparticles, maize seed germination, phytotoxicity, microparticles, root elongation, growth conditions, Petri plate, cotton, soil, X‐ray fluorescence spectrometry, environment systems, agricultural systems, ZrO₂ , SiO₂ , Al₂ O₃ , TiO₂      

Effect of Chemical Composition on Texture Using Response Surface Methodology

This study explores the effect of annealing temperature and chemical composition on crystallographic texture evolution of commercially pure aluminium alloy sheets using response surface methodology (RSM). The orientation of the crystal structure in Euler space using Bunge notation has been studied to know the behavior of the metal and estimate its volume fraction. The experimental procedure involves texture analysis with respect to annealing temperature and chemical composition in correlation with the results of formability and use of RSM. The effect of important input parameters, namely, annealing temperature and chemical composition (impurities) was used for predicting the numerical models using the volume fraction of texture output from the crystallographic study using Design Expert 8.0.7.1, trial software. Also this study explains the effect of individual chemical components, namely, iron, silicon, and copper in evolution of texture components. The volume fraction of Cube {1 0 0} 〈0 0 1〉, Bs {1 1 0} 〈1 1 2〉, and S {1 2 3} 〈6 3 4〉 components increase, whenever iron and copper content increase and silicon component decreases.     

Experimental and Prediction of Abrasive Wear Behavior of Sintered Cu-SiC Composites Containing Graphite by Using Artificial Neural Networks

Experimental investigations were undertaken to determine the abrasive wear behavior of various percentages of Cu-SiC-Gr hybrid composites. Wear tests were carried out using a pin-on-disc type machine using various input parameters like load, sliding distance, and sliding velocity with various SiC abrasive papers of grit size 80, 220, and 400, having an average particle size of 192, 102, and 45 μm. Neural networks are employed to study the tribological behavior of sintered Cu-SiC-Gr hybrid composites. Optical microscope, scanning electron microscope (SEM), X-ray diffraction (XRD), and energy-dispersive spectral observations are used to evaluate the characteristics. The proposed neural network model used the measured parameters, namely, the weight percentage of graphite, abrasive size, sliding speed, load, and sliding distance, to predict the wear loss of the composite. In order to improve the accuracy and obtain better results, an artificial neural network (ANN) with a genetic algorithm (GA) function was used. Optimization of the training process of the ANN using a GA is performed and the results are compared with the ANN trained without a GA. The predicted values from the proposed networks coincide with the experimental values.     

Effect of initial preform geometry and friction on the cold deformation behaviour of sintered titanium carbide composite steel

Cold upsetting experiments were carried on sintered titanium carbide composite steel preforms in order to assess their deformation characteristics. The effect of aspect ratio and frictional constraints on deformation behaviour have been investigated thoroughly. Cylindrical compacts with different aspect ratios were prepared, sintered and upset forged at room temperature. The above cold deformation work was carried out using 1.0 MN capacity Universal Testing Machine. Cold deformation experiments were carried out in several steps. Dimensions such as height, contact, and bulged diameters and densities were measured for each test. In general, each compact was subjected to an incremental compressive loading in steps of 0.005 MN until fine cracks appeared on its free surface. Effect of various upsetting parameters, namely, axial strain, axial stress, Poisson’s ratio on the densification has been studied.     

Effect of geometric work-hardening and matrix work-hardening on new constitutive relationship for aluminium–alumina P/M composite during cold upsetting

The densification and strain hardening behaviour during cold deformation of sintered aluminum–3.5% alumina powder metallurgy preforms were investigated by constitutive model and experimental data obtained with no and with subsequent annealing. The mechanisms most likely involved in the constitutive model, namely, densification and strain hardening were studied. The effect of geometric and matrix work hardening on the various constants involved in the constitutive model, namely, instantaneous density coefficient, instantaneous strain hardening index, instantaneous strain rate sensitivity and instantaneous strength coefficient were discussed in detail.     

Effect of SiC particle size and content on strain-based pore closure rate studies on Al–SiC P/M composites during cold upsetting

A series of laboratory-scale powder metallurgical upsetting experiments was conducted during cold upsetting on sintered Al–SiC composites. Aluminium–silicon carbide composites containing 5%, 10%, 15% and 20% SiC of four different particle sizes, namely 50, 65, 120 and 180 μm, were completely investigated. The pore closing rate and the formability strain index value were evaluated and discussed in terms of matrix and geometric work hardenings. Three novel strain-based pore closure rate indices were proposed and analysed for all the above said preforms, and their variations with respect to their relative density were plotted and discussed.     

Electropolymerized bilayer coatings of polyaniline and poly(N-methylaniline) on mild steel and their corrosion protection performance

Polyaniline (PANI) and poly(N-methylaniline) (PNMA) have been electrodeposited on mild steel from oxalic acid bath using cyclic voltammetric technique. Pretreatments like passivation and primer polymer coatings were required for effective coating. Differently stacked composite polymer layers on the metal surface by layer-by-layer approach have also been obtained and their properties have been compared with their corresponding copolymer coatings. FTIR study confirms the formation of electroactive polymer compounds on mild steel. Evaluation of these coatings in 3.5% NaCl solution by potentiodynamic polarization and electrochemical impedance spectroscopy reveals significant corrosion resistant behavior. Relatively higher corrosion protection is exhibited by copolymer coatings and composite-bilayer coatings than the corresponding homopolymer coatings. The composite metal–PANI–PNMA layer shows higher stability and better protection than the metal–PNMA–PANI layer.     

Effect of mechanical properties on wrinkling limit diagrams for Aluminum 5086 alloy annealed at different temperature

This article deals with the wrinkling limit diagrams for Aluminium 5086 alloy sheets having thickness of 2.00 mm annealed at three different temperatures namely 200, 250 and 300 °C. The study pertains to deep drawing into cylindrical cups through conical die using a flat bottom punch. When a conical die is employed, the need for a hold down or clamping ring is eliminated. However, this enhances the propensity of the blank to fail by wrinkling or buckling, particularly in the early stages of a drawing process in which thin sheet blanks are used. It is proved by these researchers and others that the onset of wrinkling takes place when the ratio of strain increments (dε_r/dε_θ) or the ratio of strain (ε_r/ε_θ) reaches a critical value during the drawing process. These values which could be determined experimentally over which the wrinkling takes place has been shown in the form of wrinkling limit diagrams for the above grade at different annealed temperatures. An attempt is also made to develop the wrinkling theory that predicts the wrinkling based on results obtained in the form of wrinkling limit diagrams established for the above grade at different annealed temperatures. Further it was observed that the annealed sheets having high n-value, high R-value and high UTS/σ_y ratio improve the resistance against wrinkling.     

Some studies on stresses and strains of aluminium alloy during extrusion-forging at room temperature

The present investigation has been undertaken to evaluate some aspects on extrusion-forging during cold upsetting using a suitable die using aluminium alloy (H9-6063) solid cylinders subjected to different geometrical conditions such as approaching angles namely, 35°, 45°, 50° and 60°, with two different initial protrusion heights namely 8 mm and 10 mm. During the experiments, three geometries such as barreled cylinder, truncated cone part and protruded part or extruded parts were observed. The calculations were made on the assumption that the volume constancy principle holds on and the curvatures of the barrel were in the form of a circular arc. Further, it is established that the protrusion height increases with the increase in the approaching angle for a given extrusion load. The relationship was also established between the various bulge parameters namely the hoop stress, the hydrostatic stress and the stress ratio parameters. In this work an attempt has been made to establish a relationship between the approaching angle and protrusion height and to establish a relationship among various height strains and stress ratio parameters.