Investigating the pulse short electric arc milling of Ti6Al4V alloy

In this study, characteristics of Ti6Al4V alloy are studied by pulse short electric arc milling (SEAM). In this regard, the influence of SEAM parameters on the material removal rate (MRR), relative electrode wear rate (REWR) and surface integrity of Ti6Al4V is studied. A wide variety of processing parameters, including different voltages, frequencies, duty cycles, flushing pressures, electrode rotation speeds and electrode feed rates are considered in the investigation. Scanning electron microscope (SEM), energy dispersive spectrograph (EDS) and micro-hardness analysis are applied to analyze results. Moreover, a multi-channel data acquisition system is used to measure gap voltage and gap current. Obtained results cover the variation of MRR, REWR, surface roughness (Ra), average re-solidified layer thickness and average heat-affected zone thickness with different processing parameters. Furthermore, the electrode surface morphology and chemical composition of the negative growth of REWR are studied. Based on the obtained results, the microstructure of the re-solidified layer and heat-affected zone of the workpiece cross-section is confirmed. This study provides a technological basis for the high-quality pulse SEAM technology of difficult-to-machine (DTM) materials to enter the semi-finishing field.

Voltammetric Sensing System for the Detection of Cholesterol Based on the Ni-Bisurea-Pyrographite Composite

Cholesterol plays a crucial role in the human body. High cholesterol level in blood is a marker of CVDs. Therefore, cholesterol determination techniques are necessary for clinical practice. Currently used cholesterol determination techniques involve enzymes or expensive and complicated equipment. Electrochemical techniques are widely spread in test-systems and sensors construction. Novel modification procedure for enzymeless cholesterol determination is suggested in this study. The electrochemical behavior of cholesterol on modified electrode was studied with the usage of cyclic and differential pulse voltammetry. Obtained concentration range is linear from 0.1 up to 100 mM a conditions close to physiological (pH=6.86) with a quantification limit of 0.01 mM. Besides, the electrode surface morphology and pH-effect were studied. The developed technique is promising for the rapid determination of total cholesterol in blood.

SODIUM LAURYL SULFATE EFFECTS ON ELECTROCHEMICAL BEHAVIOR OF POSITIVE ACTIVE MATERIAL AND COMMERCIAL POSITIVE PLATES IN LEAD-ACID BATTERY

Sodium lauryl sulfate (SLS) is an anionic surfactant used in many applications such as cleaning and hygiene products, electroplating, etc. For the first time, effects of SLS as an electroyte additive on electrochemical behavior of positive active material and commercial positive plates have been studied by cyclic voltammetry (CV), eletrochemical impedance measurements. The electrode surface morphology after 20 cycles of CV was studied by using scanning electron microscopy (SEM). Results show that SLS additive significantly improves the conversion reactions of positive active material and therefore enhances charge/discharge capacity. By increasing SLS concentrate, crystalline structure of positive active material changed. The effects of SLS on kinetic parameters of positive electrode reactions are also discussed in this paper. The results showed that SLS is promising for use as electrolyte additive for lead- acid batteries.

Electrochemical Disintegration of Activated Sludge Using Ti/RuO2 Anode

Electrochemical process is one of the most effective methods to enhance sludge disintegration. In this study, Ti/RuO2 anodes were prepared by Pechini’s method and the electrode surface morphology was characterized by FESEM and EDAX. The effects of various operating conditions were investigated including initial pH value of sludge, sludge concentration, electrolysis time and current density. The study showed that the removal efficiencies of TS, VS, TSS and VSS increased with the increase of pH in the alkaline range, electrolysis time and current density but decreased with the increase of initial sludge concentration. The application of electrochemical process using Ti/RuO2 electrodes enhanced the sludge disintegration for possible subsequent biological treatment.