Fuel distributor control of an internal combustion engine using Hilbert-Huang transformation

Article purpose: to consider the possibility of Hilbert-Huang transformation (HHT) use for vibration-acoustic control of a fuel dispenser operation in an internal combustion engine HHT was proposed by Norden Huang in 1995 to study the surface waves of typhoons. In recent years, the method has been actively used in geophysics, medicine, radio engineering, etc. Hilbert-Huang transformation makes it possible to extract information from signals about the rapid temporal changes of their spectral composition. HHT is the method of empirical mode decomposition of signals and Hilbert spectral analysis.The article presents the results of vibration-acoustic signal processing of an internal combustion engine using HHT. The series of experiments was carried out in a test laboratory on a motorized bench (eight-cylinder two-stroke engine). The measurements of vibrationacoustic signals were carried out for the periods when the engine operates in normal mode and when one of the cylinders is not working (the supply to the fuel dispenser is switched off). It was determined that the 9th empirical mode (Intrinsic mode functions) contains the basic harmonic components of a signal. When the fuel dispenser of one of the cylinders is disconnected, the asymmetry of the instantaneous frequencies distribution of the 9th IMF appears relative to their average value. During the analysis of their central third-order moment, it is possible to establish the state of the controlled object properly.Keywords: Hilbert-Huang transformation, empirical mode decomposition by ensemble, instantaneous frequency, third-order central moment, nondestructive testing, internal combustion engine, vibration-acoustic signa

Neural network analysis of vibration signals in the diagnostics of pipelines

The article is devoted to the improvement of heat network calculation and diagnostics methods. Currently used instruments have many shortcomings for the diagnosis of pipelines, including low reliability of defect detection and subjective decision-making. The authors created an experimental stand, which allows to conduct the diagnostics of pipelines by a vibration-acoustic method. They studied steel pipes filled with water, the surface of which 50x50 mm defect and the depth of thinning of 2 mm, 3 mm, and 5 mm. Using the vibrationacoustic sensors fixed on an outer surface, the vibration signals generated by the water flow in the pipe were obtained. In order to process the large volumes of data obtained as the result of experiments, it is proposed to use artificial neural networks. Among all considered types of neural networks, the authors prefer Kohonen's networks due to the best effectiveness of a defect determination. The program for an acoustic signal processing and analyzing through a neural network was implemented in LabView 8.5 work environment. Depending on the accuracy of a problem being solved, and the details of a training sample, the program is able to produce the results of sample classification of samples for a defect-free and defective pipes of different depth of damage. The results of the classification by Kohonen's trained neural network show good abilities for the analysis of unknown samples and a high degree of their recognition reliability.Keywords: diagnosis, corrosion, defect, pipelines, acoustic signal, neural networ

The conflictual dynamics of polities and ethnopolitogenesis

© Medwell Journals, 2016.The study puts forward the idea of relationship of polities dynamics with ethnogenetic dynamics that allows to suggest the existence of ethnopolitogenesis as a single process. The ethnogenetic dynamics is expressed by the fact that the ethnicity undergoes throughout its life a series of age phases, stable periods and phase transitions separating these periods-unstable crisis periods, for which is specific large-scale domestic conflicts and major military defeats of the state established by it. The ethnogenetic dynamics is determined by the population qualitative composition dynamics, i.e., by the dynamics of the proportion of the individuals of different energy types as the part of the ethnic group. It's developed a universal and invariant regularity with regard to polity types, ethnicities and historic epochs, linking the polity dynamics in its conflictual aspect with the dynamics of population quality, the numerical algorithm of ethnopolitogenesis. The following hypothesis is stated that at the bottom of the algorithm existence is the synchronization dynamics quality by climatic cycles associated with solar activity cycles

Population Characteristic of the Volga zander Sander volgense (Percidae) in the Kuibyshev reservoir

© 2016, Pleiades Publishing, Ltd.The analysis of the size composition, age structure, linear growth, and fecundity of the Volga zander Sander volgense has been performed in the Kuibyshev reservoir. To date, the growth rates of the species have decreased slightly compared to the 1970s. Over the period from 2000 to 2013, catch volumes of Volga zander tended to increase

Optimization of burning process of hydrocarbon fuels with varying specific heat of combustion

© Published under licence by IOP Publishing Ltd. This article explores the combustion of gaseous fuel in the case of an abrupt change of the specific heat of combustion. Analyzes the changes in the rate of heat when the fuel and air flows are constant. Defines the conditions for which retained the initial rate of heat release and optimal fuel-air ratio

Testing method for riveted connections using the free oscillation technique. Numerical simulation

© 2016, International Journal of Pharmacy and Technology. All rights reserved.The article presents the results of studies on the development of methods and diagnostic system for instrumental quality control of riveted connections using the automated free oscillation technique. Based on the analysis of the known non-destructive testing methods of a riveted connection, it has been concluded that application of the free oscillation technique is very promising for quality control in the manufacture and repair of the gas turbine engine’s stators in order to identify different types of defects. The free oscillation technique (FOT) relies on excitation of freely damped elastic oscillations in a test object or part thereof and analysis of parameters of these oscillations. The FOT informative parameter is the change in the spectrum of free elastic oscillations of test objects. In order to accelerate the development of certain testing methods, the numerical experiments were carried out to determine the natural frequencies of suitable and defective riveted connections. Following the numerical simulation results, the optimal method of attaching a test disc to blades and informative frequency ranges were determined; they indicate that some defects of riveted connections are available

Inspection of riveted connections by free oscillation technique.Inspection of riveted connections for “riveted wheel blades” at the production stage

© 2016, International Journal of Pharmacy and Technology. All rights reserved.The article presents the results of the production testing of the diagnostic system for quality instrumentation inspection for riveted connections with free oscillations technique. The test program consisted of four stages. In the first stage we selected guide cases which were new and spent a part of their resource having characteristic defects of riveted connections. In the second stage we formed reference spectra of inspected connections. At the third stage we established the relation between the numerical value of the Spearman correlation coefficient and the shear force of a blade. In the fourth stage, all tested connections were sent to additional riveting. Following the inspection with the free oscillations technique and on shear force, we have determined that shear force momentis constant and defective riveted connections were absent upon established rejectable quality levelis 0.75 of Spearman correlation coefficient. According to the tests results it is recommended to set the rejectable quality limit with regard to evaluation of Spearman correlation coefficient at 0.75that corresponds to 10 N m shear force moment of a blade. The developed inspection technique allows grading of riveted connection as “defected” and “fit” without unproductive manual inspection. Application of the technique allows quickly and with a high degree of certainty to reveal defective riveted connections in GTE guide cases what increases engine reliability and allows saving time and costs to determine the technical condition of gas turbine plants. The instrumental technique is implemented in the non-destructive inspection complex where the positioning of the inspected product, recording, analysis of vibro-acoustic signal and making conclusion on the conditions of a product is performed automatically, without operator intervention, that eliminates subjectivity in the decision-making