Elimination of phenol from refineries effluents using electrocoagulation method

The crude oil industry is a major source of water pollution because of huge volumes of refining effluents discharged into the aquatic environment. This effluent consequently consists of substances that causes harm to the aquatic environment and depletes the aquatic population due to depleted oxygen. This study investigated the application of various treatment procedures and materials to reduce the effects of refining process effluent on water. The current study proposes to employ the electrocoagulation (EC) method in the removal of phenol contamination from refining effluent utilising aluminium electrodes. Continuous flow studies have been carried out in order to remove phenolic chemicals from refinery effluent effects of experimental factors such as electrical current density (ECD), distances between electrodes (DE), and treatment durations (TD) while phenols were eliminated were examined. The results show that the EC method reduced the phenol level in petroleum refinery discharge. The EC unit decreased the phenol level by 57% using aluminium as electrodes. The-optimal removal efficiency was found at 120 TD with an ECD of 6 mA/cm2 and a DE of 20 mm.

Effect of the Current Density in the Electrical Resistance Sintering Technique to Fabricate a β-Ti-Nb-Sn Ternary Alloy for the Biomedical Sector

The electrical resistance sintering is a fast method to fabricate metallic samples in the field of metallurgy and it was used to obtain the Ti-Nb-Sn alloy to be applied as biomaterial, variyng different electrical current densities (11, 12 and 13 kA). The powders were obtained by mechanical alloying, then they were compacted at pressure of 193 MPa during 700 ms. The structure and microstructure of the powders and the samples was evaluated by x-ray diffraction, by Field Emission Scanning Electron Microscopy and electron back-scattered diffraction. The mechanical properties were evaluated by microhardness assay and corrosion resistance was made in Ringer Hartmann’s solution at 37ºC. The samples are formed by α, α” and phase β. The % of phase β in the samples obtained at 11, 12 and 13 kA was 96.56, 98.12 and 98.02 respectively. The peripheral zone present more presence of microporosity than the central zone. The microstructure is also formed by bcc-β grains equiaxial, and the samples obtained at 12 kA present better homogeneity of the microstructure. The grain size increased with the increase of the electrical current density. The microhardness are in the range of 389-418 HV and decreased with the increase of electrical current density. Corrosion tests proved excellent corrosion resistance of the alloys (0.24-0.45 µA/cm2). The standard deviation of kinetic parameters of the samples at 11 and 13 kA were very higher, related to the lack of homogeneity of the microstructure.

Development of an Oxygen Pressure Estimator Using the Immersion and Invariance Method for a Particular PEMFC System

The fault detection method has been used usually to give a diagnosis of the performance and efficiency in the proton exchange membrane fuel cell (PEMFC) systems. To be able to use this method a lot of sensors are implemented in the PEMFC to measure different parameters like pressure, temperature, voltage, and electrical current. However, despite the high reliability of the sensors, they can fail or give erroneous measurements. To address this problem, an efficient solution to replace the sensors must be found. For this reason, in this work, the immersion and invariance method is proposed to develop an oxygen pressure estimator based on the voltage, electrical current density, and temperature measurements. The estimator stability region is calculated by applying Lyapunov’s Theorem and constraints to achieve stability are established for the oxygen pressure, electrical current density, and temperature. Under these estimator requirements, oxygen pressure measurements of high reliability are obtained to fault diagnosis without the need to use an oxygen sensor.

Wireless retina implant with large visual field

We present the concept of a novel epiretinal prosthesis, consisting of a foil-based, miniaturized electronics with wireless optical energy and signal transmission and integrated electrostimulation. The aim is achieving a wideangle projection to create a large visual field. The implant having a diameter of 14 mm consists of a mosaic-like array of thinned silicon-based photodiodes combined with a polyimide foil. This thin implant, realized on a flexible foil for the first time, adapts to the curvature of the eye. Thin-film stimulation electrodes on the foil are electrically connected to the photodiodes. The influence of the electrode geometry on the electrical current density at the location of electrostimulation is investigated by computer simulations. First experiments towards realization of via holes in a 10 μm thick polyimide layer were successful and led to vias with inclined sidewalls and rounded openings. This shape is advantageous concerning uninterrupted conductor paths leading from the photodiodes to the stimulation electrodes.

Electro Sinter Forging (ESF)

Electro sinter forging (ESF) represents an innovative manufacturing process dealing with high electrical currents. Classified in the category of electrical current assisted sintering (ECAS) processes, the main principle is that Joule heating is generated inside the compacted powder, while the electrical current is flowing. The process is optimized through the analysis of the main process parameters, namely the electrical current density, sintering time, and compaction pressure, which are also evaluated as process fingerprints. The analysis was conducted on commercially pure titanium powder. Small discs and rings were manufactured for testing. The influence of the process parameters was analysed in terms of the final material properties. The relative density, microstructures, hardness, and tensile and compressive strengths were analysed concerning their validity as product fingerprints. Microstructural analyses revealed whether the samples were sintered or if melting had occurred. Mechanical properties were correlated to the process parameters depending on the material. The different sample shapes showed similar trends in terms of the density and microstructures as a function of the process parameters.

Electrodeposition of Copper/Carbonous Nanomaterial Composite Coatings for Heat-Dissipation Materials

Carbonous nanomaterials are promising additives for composite coatings for heat-dissipation materials because of their excellent thermal conductivity. Here, copper/carbonous nanomaterial composite coatings were prepared using nanodiamond (ND) as the carbonous nanomaterial. The copper/ND composite coatings were electrically deposited onto copper substrates from a continuously stirred copper sulfate coating bath containing NDs. NDs were dispersed by ultrasonic treatment, and the initial bath pH was adjusted by adding sodium hydroxide solution or sulfuric acid solution before electrodeposition. The effects of various coating conditions—the initial ND concentration, initial bath pH, stirring speed, electrical current density, and the amount of electricity—on the ND content of the coatings were investigated. Furthermore, the surface of the NDs was modified by hydrothermal treatment to improve ND incorporation. A higher initial ND concentration and a higher stirring speed increased the ND content of the coatings, whereas a higher initial bath pH and a greater amount of electricity decreased it. The electrical current density showed a minimum ND content at approximately 5 A/dm2. Hydrothermal treatment, which introduced carboxyl groups onto the ND surface, improved the ND content of the coatings. A copper/ND composite coating with a maximum of 3.85 mass% ND was obtained.