Optimisation of grinding parameters for wheel loading and dressing
Grinding is a finishing process often used to produce desired surface roughness with required precision and quality. The performance of grinding wheel significantly depends on the nature of the wheel, morphology of the abrasive grits and the grinding parameters namely speed, feed and depth of cut. As the wheel is performing its grinding operation, its cutting surface is being loaded with metal particles of the workpiece. This wheel loading also affects the surface finish of the workpiece. Hence monitoring the grinding wheel loading and dressing at proper time intervals becomes mandatory to get the desired surface finish. In the quest of developing a low cost monitoring system, it is good enough to analyse the wheel loading on widely used metal specimens such as mild steel, HCHCr steel and aluminium under optimised cutting conditions using the conventional silicon carbide and aluminium oxide wheels for better evaluation of the results. In this work the grinding parameters are optimised by using ANOVA technique. A full factorial experiment was carried out at 5% level of significance, i.e. at 95% confidence level.
Determining the Effects of Machining Parameters and Modifier on Surface Roughness in Dry Turning of Al-20%Mg2Si-PMMC using Design of Experiments (DOE)
The machinability of particulate metal matrix composites (PMMC) is influenced by the matrix mechanical properties as well as size, distribution and volume fracture of reinforcement particles. In order to machine different PMMCs, especial machining conditions based on the type of operation must be considered. The main principle aim of this observation is to assess the effect of machining parameters involving cutting speed, feed rate and Strontium addition on surface roughness of Al-20%Mg2Si in-situ composite. In this study design of experiment (DOE) methodology was applied to design experimental trials and the results were analyzed using Analysis of Variance (ANOVA). The dry turning was done on ALPHA 1350S CNC lath machine with a new insert for each test to ensure accurate reporting. The results showed that the Mg2Si particles morphology such as size, shape and distributions have altered by Sr addition. The statistical analysis revealed that all main effects influenced the surface roughness. The predicted results are found to be so closer to actual results. Due to low proximity difference between predicted results and actual results with each other, based on confirmation tests, the predictive model is sufficient accurate at reliability of 95%.
Electrochemical detection of copper(II) at a gold electrode modified with a self-assembled monolayer of penicillamine
A penicillamine (PCA) self-assembled monolayer (SAM) was prepared on a gold electrode. It has been found that the modified electrode exhibited a selective response to copper ions. As demonstrated by cyclic voltammetric experiments, the SAM-based electrode showed an attractive ability to preconcentrate efficiently traces of copper(II) from solutions. Under optimum conditions, the anodic peak current was proportional to the concentration of Cu(II) in the range from 8.0 × 10−7 to 1.0 × 10−4 M with a detection limit of 4.0 × 10−7 M. Moreover, this modified gold electrode is also characterized by excellent repeatability, showing a relative standard deviation of 3.2% for nine successive measurements of 1.0 × 10−5 M Cu(II). The PCA/Au SAM gold electrode was used for the determination of Cu(II) in a tap water sample and the results showed a good agreement with the data obtained by atomic emission spectrometry.