Measuring Setup for Investigation and Visualization of the Percolation Phenomenon in Non-Оrdered Models of Metal-Dielectric Nanocomposites

The study uses the phenomenon of high voltage partial discharge to investigate the phenomenon of percolation and visualisation of the percolation channel. The phenomenon of partial discharges is very similar to the quantum tunneling phenomenon observed in metal-dielectric nanocomposites. In both cases the flow of alternating current occurs in the absence of direct contact between the metallic phase particles.A measuring stand was developed and constructed to test models of metal dielectric nanocomposites using high voltage partial discharge. The stand consists of a 110 kV high voltage transformer, a voltage regulator protecting the constant rate of high voltage rise, a measuring system consisting of a measuring probe, voltmeters and a computer. The communication between the measuring probe and the voltmeter was made in digital technology with the use of fiber optic technology, which allowed the meter to communicate with the computer without any errors and eliminated the interference caused by a strong electromagnetic field resulting from the use of high voltage.Systems modelling metal-dielectric composites were built, consisting of metallic elements in the form of disks, randomly distributed on the surface of the dielectric matrix. The number of disks was increased in series of 40 in each. The maximum number of disks was 1520. The dependence was determined of one of the important parameters characterising an partial discharge, i. e. the initial voltage, at which an electric current starts to flow between electrodes, on the concentration of the metallic phase. On the basis of these results, a percolation threshold was established for a matrix with a random distribution of metallic phase elements, the value of which is about 50 %. Films and pictures of partial discharges with visible percolation channels were taken with the camera with which the stand was equipped.

Calculation of the accuracy of a control head of a simplified design for dimensional control of parts

The metrological scheme of the control head of a simplified design is presented, its kinematic accuracy is analyzed. It is shown, that the effectiveness of the use of the head of this design, i.e., the accuracy of control, when controlling tolerances, in the manufacture of the part depends on the choice of the length of the measuring probe. Keywords part, size, control, measuring probe, kinematic accuracy, metrological scheme. [email protected]

Effect of processing of bovine milk on gastrointestinal symptoms and intestinal pressure in sensitive individuals

Over the last years, the consumption of unpasteurised milk has increased in popularity in the Western countries, despite the known risks associated with food-borne pathogens. Some people appear to experience milk-related gastrointestinal symptoms even when tested negative for lactose intolerance and milk allergy. In such cases, processing of milk, most often homogenisation or heat treatment, has been suggested to be involved in the induction of the gastrointestinal symptoms. Commercial milk is generally homogenised for the purpose of physical stability. Homogenisation reduces the size of fat droplets. Breaking of the fat globules creates new interface, which is covered with denaturated proteins. Further denaturation level of the proteins depends on the severity of the heat treatment. In this study entity, the effect of processing of bovine milk on the gastrointestinal symptoms in self-reported milk sensitive individuals was tested in two separate double blind crossover trials. Tested milks included raw milk (unprocessed), pasteurized milk, pasteurized and homogenized milk, and UHT treated and homogenized milk thus including milks at both end of commercially approved liquid milks in Finland. All milks came from the same herd of cows, which nulled the effect of genetic background and feeding of the cows. Ingestible pH-, pressure and temperature measuring probe was used to investigate gastrointestinal pressure. Self-reported diaries were used to measure perceived gastrointestinal symptoms. Additionally inflammation markers were studied from the plasma. In the first trial no significant difference was found in the amount of gastrointestinal symptoms or in the intestinal pressure after the consumption of native and processed milk. However, the obtained results on pressure in the large intestine (P = 0.068) as well as reported symptoms (P = 0.103) suggested that further studies in this area were needed. However, in the second trial where pasteurised, pasteurised and homogenised, and UHT -treated and homogenized milks were compared, the amount, severity or duration of the reported symptoms did not differ. This study demonstrates that the ingestible pressure-, pH and temperature measuring probe provided a novel possibility to study intestinal pressure in nutrition trials. The results of the present studies do not support the hypothesis that cows’ milk processing would induce gastrointestinal symptoms in milk sensitive but lactose tolerant subjects.

An electromechanical impedance-instrumented corrosion-measuring probe

Corrosion of metallic structures widely existed in multiple industries, such as oil and gas, civil infrastructure, aerospace, mechanical, mining, and processing. Current available corrosion-monitoring methods are based on different sensing principles, which have their own advantages, and some drawbacks that may limit their application on some aspects. This article presents an electromechanical impedance-instrumented corrosion-measuring probe for corrosion monitoring. The proposed probe is fabricated by attaching a circular lead zirconate titanate patch onto a metal rod. Compared to other electromechanical impedance-based corrosion-monitoring methods, the probe is capable of isolating the influence of structural complexity, variations in loading and boundary conditions. Five probes were fabricated in the experimental study and three of them were subjected to accelerated corrosion tests to mimic the corrosion-induced mass loss damage. Results showed that the peak magnitude of the conductance signatures was reduced with the increase in corrosion amount. The variations in the conductance signatures were quantified by three statistical quantifying metrics, that is, root-mean-square deviation, mean absolute percentage deviation, and correlation coefficient deviation. All these metrics increase with the increase in corrosion amount, which can be used as an indicator of the corrosion process. This study proves that the proposed corrosion-measuring probe is effective in monitoring corrosion and shows promising application potential. This research also serves as a proof-of-concept study to demonstrate the capability of the electromechanical impedance technique in monitoring mass loss due to corrosion.