ARTIFACTS ON EEG: IDENTIFICATION AND DIFFERENTIAL DIAGNOSIS

Artifacts produced in the course of electroencephalographic studies (EEG) is a defect of the recording. Modern equipment detects electroencephalographic extremely small values of changes of bioelectric potentials, and therefore the true EEG recording may be distorted due to the impact of various physical (technical) and / or physiological artifacts. Often this makes it very difficult for her explanation and interpretation. The purpose of this article is demonstration of the most typical artifacts that appear during EEG recording to increase the knowledge of doctors conducting EEG study. It is shown that almost all of EEG artifacts have specific (unique) features that allow to experienced doctors separate them from the main record. Therefore, even during the study on the modern diagnostic equipment EEG-technician and doctors must recognize the recorded artifacts, doing its best efforts to remove them from the main recording of EEG

On the Determination of the Gear Teeth Wear Using an Inductive Sensor

A problem to measure the teeth wear of rotating gear wheels and a possibility to create simple, reliable and inexpensive mobile systems of diagnostics allowing to record the wear in the course of use are presently relevant. The paper presents implemented technical solutions as a result of work. The aim of the work was to prove experimentally that it is possible to measure the teeth wear of a gear wheel using a passive inductive sensor and a positioning disk. The technique to determine the wear uses a phase-chronometric method developed at BMSTU.To reach the objective, an experimental installation was designed and made. Works are performed, and experimental results of used stationary inductive sensors of passive type to measure the ferromagnetic gear wheels wear of reducers in use are received. The technique for defining the points at the output signal of the inductive sensor, which correspond to the specified points of the tooth profile and, in particular, to the profile points on a pitch circle of the tooth of gear wheel has been developed. Experiments allowed us to define the main dependences of signal parameters on the sizes and arrangement of the sensor magnet with respect to the passing tooth in the course of rotation, as well as on the number of the sensor coil turns, speed of gear wheel rotation, and on the gap size between the end face of the sensor and the top of a tooth.The technique for positioning the sensor with respect to tooth has been deve loped. In particular, it allows us to position a sensor at any point of the involute, including also a point of the profile on a pitch circle. This is necessary to adjust the sensor. The conducted researches allowed us to develop a technique for exact measuring system adjustment to a hitch circle of the gear wheel and to develop for this purpose a system of diagnostics and measurement of teeth wear with the wheel being rotated. The results of work performed at the JSC ELARA in Cheboksary city allowed us to develop a design and make a pilot batch of standard ind uctive sensors, which can be used in mechanical engineering in systems of diagnostics of reducers in a diversity of machines and mechanisms.</p

Calculation of the quantity of oxygen required for maintenance of the predetermined temperature of steel during its boiling period in a steel-melting arc furnace

The article provides а mathematical model of steel smelting in a steel-melting arc furnace with provision for calculation of necessary quantity of oxygen for maintenance of preset temperature of steel when arcs are switched off It shows that oxygen supply during the arcs disconnection period secures energy consumption reduction