Unusual cases of suicidal electrocution using a homemade device

Background The common methods of suicide are hanging and poisoning. Suicidal electrocution using a homemade device is very rare. Victims usually possess knowledge of electrical circuits. Here, we report two cases of suicide by electrocution using a homemade device. Case presentation: Case 1: A retired electrical technician was found unresponsive in his bedroom, with two bare copper wires; one encircling the index finger of the left hand, and the other placed in the mouth. The other ends of the wires were connected to a wall plug supplying 220 V current. Forensic autopsy and microscopic findings attributed death to suicidal electrocution. Case 2: A 51-year-old-man was found dead in the bathroom with bare copper wires encircling both wrists and connected to a wall plug carrying 220 V current. Death scene investigation, necropsy, histological tests and toxicological screening indicated suicide by electrocution.

Experimental and Numerical Simulation Study of the Vibration Properties of Thin Copper Films Bonded to FR4 Composite

Printed circuit boards constitute the basis of most electronic devices and are mainly fabricated of thin copper films bounded to fiber epoxy laminates, such as FR4. Vibrational stress can induce device failure, and hence, studies addressing their modal properties have important applications. In this paper, cantilever samples made of bare copper bounded to FR4 have been studied to analyze, for the first time, the vibration behavior of specimens with different aspect ratios, with and without central holes of different diameters. Natural frequencies and damping ratios were determined experimentally and analytically using a finite element method for four groups of samples with a very good correspondence between both methods. The fundamental resonance frequency of all the specimens was found to be less than 40 Hz and the influence of a central hole was not significant to affect the modal properties.

Enhancement of Photoelectrochemical Cathodic Protection of Copper in Marine Condition by Cu-Doped TiO2

Photochemical cathodic protection (PEC) efficiency was enhanced by doping TiO2 with Cu (Cu/TiO2) through impregnation and reduction under hydrogen. The Cu loading was vaired from 0.1 to 1.0 mol% (0.1 Cu/TiO2, 0.5 Cu/TiO2, 1 Cu/TiO2). Then, up to 50 wt% Cu/TiO2 was mixed with TiO2 to form nanocomposite films. The film photocurrent and photopotential were measured under 1 mW/cm2 UV irradiation. The Cu/TiO2 film with 10 wt% of 0.5 Cu/TiO2 exhibited the highest photocurrent of 29.0 mA/g, which was three times higher than the TiO2 film. The underlying reason for the high photocurrent was the lower photopotential of film than the corrosion potential of copper for PEC. This film was also applied on copper terminal lug for anti-corrosion measurement by Tafel polarization in 3.5 wt% NaCl solution. The results showed that the photopotential of terminal lug coated with the film was −0.252 V vs. Ag/AgCl, which was lower than the corrosion potential of copper (−0.222 V vs. Ag/AgCl). Furthermore, the film can protect the corrosion of copper in the dark with 86.7% lower corrosion current (icorr) than that of bare copper.

Study of droplet dynamics and condensation heat transfer on superhydrophobic copper surface

Superhydrohobic surface for dropwise condensation is prepared using hotplate solution immersion method on copper substrate. The preprocessed bare copper plate is immersed in a solution consist of 0.004 - 0.008M ethanol (CH3?CH2?OH) and tetradecanoic acid (CH3(CH2)12COOH) then heating the plates in the solution at 30 - 50?C for 1 - 6 hours. The contact angle of water droplet on the prepared surface is measured using Low Bond Axisymmetric Drop Shape Analysis (LBADSA), which gives the maximum contact angle of 168? and average value of 166? ? 2?. The maximum contact angle is obtained by adjusting the composition of the solution, temperature of the solution and immersion time to 0.006M, 45? and 4 hours respectively. The various superhydrophobic surfaces are prepared by changing constituents of solution, hotplate temperature and processing time respectively. Further dynamic behavior of water droplet on the prepared surfaces like jumping effect and rolling effect is presented in this work. In addition, experimental work is carried out on the prepared surface for dropwise condensation and the obtained results are compared with condensation on bare copper plate produces higher heat transfer coefficient.

Electrical Discharge Machining Characteristics of ECAP Copper Electrode

Enormous research work has done on the electrode wear in spark erosion machining such as hybrid electrical discharge machining process, introducing various methods such as ultrasonic vibration in electrode, rotating the electrode, developing new electrode material (alloys and composites) and surface coated electrode etc,. Equal Channel Angular pressing is one such technique which makes tool material harder through grain refinement and ultimately enhances the tool life. The work material is AISI H13. For this research work, two copper electrodes are prepared, out of which one copper electrode has undergone equal channel angular pressing process. The most influencing parameters of spark machining like current, pulse on time and pulses off time are chosen for this study. The experiments are conducted using bare copper electrode and equal channel angular pressed copper electrode based on the box Behnken approach. The observations are analyzed for the machining characteristics in terms of rate of machining, rate of tool erosion and surface coarseness. Finally, it is found that ECAP processed copper electrode has lesser wear rate and better surface finish than bare copper electrode.