scholarly journals Methods of Research of Foil Bearings in START-STOP Cycle in the Presence of Working Medium

2019 ◽  
Vol 23 (4) ◽  
pp. 41-51
Author(s):  
Bartosz Moczulak ◽  
Wojciech Miąskowski
Keyword(s):  
Test Chamber ◽  
Test Cycle ◽  
Time Intervals ◽  
Sliding Bearings ◽  
Foil Bearings ◽  
Working Cycle ◽  
Automatic Mode ◽  
Working Medium ◽  
Stop Test ◽  
Selection Of

AbstractA method for testing sliding bearings with an elastic bearing liner was presented in the paper with a focus on the issue of selection of particular time intervals of the START-STOP test cycle. Then, results of the tests carried out according to the selected material combinations were presented. The working cycle of foil bearings tested on the test stand was performed in an automatic mode at the set number of sequences start-work-rundown-stop. Due to the highest use of sliding bearings during start and rundown of a machine, this type of tests is essential for selection of relevant sets of material for bearing elements. The article also presents the use of a thermo-visual camera for identification of additional thermal loads and manners of temperature stabilization in the test chamber.

scholarly journals Methodology of Testing Foil Bearings in the Start-Stop Cycle in the Presence of a Working Medium - Stabilization of Temperature in the Test Chamber

2020 ◽  
Vol 24 (3) ◽  
pp. 63-72
Author(s):  
Bartosz Moczulak ◽  
Wojciech Miąskowski
Keyword(s):  
Temperature Increase ◽  
Test Chamber ◽  
Time Interval ◽  
Flexible Shell ◽  
Specific Time ◽  
Test Cycle ◽  
Sliding Bearings ◽  
Foil Bearings ◽  
Working Medium ◽  
Stop Test

AbstractThe article presents the methodology of testing sliding bearings with a flexible shell, focusing on the issue of temperature increase during experiments for a specific time interval of the START-STOP test cycle. Selected material pairs, used in previous studies, were used in the experiment. The stand used for tests in the start-stop cycle was developed under the project POIG.01.03.01-00-027 / 08-00 at the Faculty of Technical Sciences UWM in Olsztyn.

scholarly journals Classifying the Biological Status of Honeybee Workers Using Gas Sensors

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 166
Author(s):  
Jakub T. Wilk ◽  
Beata Bąk ◽  
Piotr Artiemjew ◽  
Jerzy Wilde ◽  
Maciej Siuda
Keyword(s):  
Gas Sensors ◽  
Laboratory Tests ◽  
Test Chamber ◽  
Ambient Air ◽  
True Positive Rate ◽  
True Positive ◽  
Positive Rate ◽  
Parameters Of Accuracy ◽  
Selection Of

Honeybee workers have a specific smell depending on the age of workers and the biological status of the colony. Laboratory tests were carried out at the Department of Apiculture at UWM Olsztyn, using gas sensors installed in two twin prototype multi-sensor detectors. The study aimed to compare the responses of sensors to the odor of old worker bees (3–6 weeks old), young ones (0–1 days old), and those from long-term queenless colonies. From the experimental colonies, 10 samples of 100 workers were taken for each group and placed successively in the research chambers for the duration of the study. Old workers came from outer nest combs, young workers from hatching out brood in an incubator, and laying worker bees from long-term queenless colonies from brood combs (with laying worker bee’s eggs, humped brood, and drones). Each probe was measured for 10 min, and then immediately for another 10 min ambient air was given to regenerate sensors. The results were analyzed using 10 different classifiers. Research has shown that the devices can distinguish between the biological status of bees. The effectiveness of distinguishing between classes, determined by the parameters of accuracy balanced and true positive rate, of 0.763 and 0.742 in the case of the best euclidean.1nn classifier, may be satisfactory in the context of practical beekeeping. Depending on the environment accompanying the tested objects (a type of insert in the test chamber), the introduction of other classifiers as well as baseline correction methods may be considered, while the selection of the appropriate classifier for the task may be of great importance for the effectiveness of the classification.

Counseling Parents of Children With Behavior Problems: The Use of Extinction and Time-Out Techniques

PEDIATRICS ◽  
1977 ◽  
Vol 59 (1) ◽  
pp. 78-85
Author(s):  
Ronald S. Drabman ◽  
Greg Jarvie
Keyword(s):  
Problem Behaviors ◽  
Inappropriate Behavior ◽  
Time Intervals ◽  
Alternative Behavior ◽  
Home Setting ◽  
Time Out ◽  
Behavior Response ◽  
Disciplinary Problems ◽  
The Family ◽  
Selection Of

The pediatrician is the professional most frequently sought out for advice concerning disciplinary problems with children in the home. Behavioral psychologists have advocated the use of contingent ignoring and time-out procedures to help reduce problem behaviors; however, practicing pediatricians have found that these two procedures are often not successful. In fact, sometimes the two procedures seem to exacerbate inappropriate behavior. This paper documents the difficulties found in using the ignoring and/or time-out procedures in the home setting. Potential pitfalls in the use of ignoring, including not specifying the target behavior, not taking a baseline, inadvertently, intermittently reinforcing the inappropriate behavior, response bursts, spontaneous recovery, and not reinforcing an appropriate alternative behavior, are described. In addition, several pitfalls in the use of the time-out procedure, including selection of isolation area, inappropriate selection of time intervals, interference from others in the family, and escape attempts on the part of the child are discussed. For each potential problem a remedy is suggested.

Application of precision chronometric technologies for monitoring deviations in the internal combustion engine operation

2021 ◽  
Author(s):  
E.T. Plaksina ◽  
A.B. Syritsky ◽  
A.S. Komshin
Keyword(s):  
Internal Combustion Engine ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Internal Combustion ◽  
The Arctic ◽  
Diagnostic Systems ◽  
Time Intervals ◽  
Angle Sensor ◽  
Engine Operation ◽  
Working Cycle

The article considers the main methods of internal combustion engine diagnostics. A method based on measuring the time intervals between the phases of the working cycle of the mechanism is described. An algorithm for measuring the time intervals from the formulation of the problem to the proof of the efficiency of this method on an internal combustion engine has been determined. The installation of the angle sensor on the crankshaft of the experimental bench engine VAZ 21126 is shown. The basis for the construction of a mathematical model of the crankshaft is presented and the main factors influencing its movement are identified. A criterion has been established according to which the misfire is determined most accurately. The results obtained can be used for developing diagnostic systems for internal combustion engines, as well as engines operating in extreme conditions, for example, beyond the Arctic Circle, on ships, etc.

scholarly journals Adaptive multivariable relay protection of reconfigurable distribution networks

2019 ◽  
Vol 139 ◽  
pp. 01048
Author(s):  
Mikhail Sharygin ◽  
Vladimir Vukolov ◽  
Anton Petrov
Keyword(s):  
Distributed Generation ◽  
Hardware Implementation ◽  
Human Factor ◽  
Dynamic Change ◽  
Relay Protection ◽  
Distribution Networks ◽  
New Methods ◽  
Automatic Mode ◽  
Relative Selectivity ◽  
Selection Of

Version of relay protection construction of relative selectivity is proposed, which allows increasing its technical perfection and reliability in microgrids with distributed generation sources. This is done by increasing the dimension of the measurement space along arbitrary axes, introducing new methods of recognizing emergency modes, as well as automating the selection of response parameters. Hardware implementation of protection is described. Recommendations for calculating the settings of multidimensional protection and an example of calculation are given. Protection coordination is carried out by using graphical-analytical methods in automatic mode. Automation of the calculation, elimination of the human factor will make it possible to apply the method for adaptation of protection in the conditions of dynamic change of microgrid topology.

Vibroacoustic Study of Abrasive Wear of Multilayered Sliding Bearings

2019 ◽  
Vol 822 ◽  
pp. 662-668
Author(s):  
Andrey Vladimirovich Tikalov ◽  
Leonid Vladimirovich Yefremov
Keyword(s):  
Abrasive Wear ◽  
Friction Model ◽  
Sliding Bearings ◽  
Grain Sizes ◽  
Vibroacoustic Diagnostics ◽  
Selection Of

The article substantiates consistent patterns of wear at the example of microcutting materials in sliding bearings in dependence to grain sizes of abrasive cloths and hardness of bearing layers received with the use of vibroacoustic diagnostics and the method of artificial bases (MAB) in testing on the SMC-2 frictional machine. These patterns can be helpful for the assessment of quality and selection of materials for products [1,2], selection of the friction model [3], and selection of abrasive cloths for the diagnostics of the latter and assessment of the running-in period for the top coating.

scholarly journals Electrochemical Behaviour of Tocopherols: Possibilities of Their Simultaneous Voltammetric Detection

2021 ◽  
Vol 11 (17) ◽  
pp. 8095
Author(s):  
Granit Jashari ◽  
Gylxhane Kastrati ◽  
Lucie Korecká ◽  
Radovan Metelka ◽  
Milan Sýs ◽  
...  
Keyword(s):  
Electrochemical Behaviour ◽  
Simultaneous Detection ◽  
Lithium Perchlorate ◽  
Electrochemical Technique ◽  
Naturally Occurring ◽  
Wave Voltammetry ◽  
Working Medium ◽  
Voltammetric Detection ◽  
Medium Selection ◽  
Selection Of

An electroanalytical study for possible simultaneous detection of three naturally occurring isomers of vitamin E (α, γ, and δ-tocopherol) was performed. This research includes several optimization steps, such as selection of electrode material, composition of working medium, selection of electrochemical technique, and parameters of square-wave voltammetry (SWV), to reach a well-defined recognition of peaks. A glassy carbon electrode, 99.9% acetonitrile containing 0.1 mol L−1 lithium perchlorate, SWV at the potential step of 1 mV, potential amplitude of 25 mV, and frequency of 25 Hz were decided as the most suitable working conditions. Nevertheless, the corresponding anodic peaks were not sufficiently separated due to their overlapping. Thus, four standard evaluation methods (polynomial or linear baseline, zero base, and deconvolution) were compared, and the last-mentioned method was chosen as optimum. Similar linear ranges from 3.0 × 10−6 to 1.0 × 10−5 mol L−1 were obtained for α, γ, and δ-tocopherol, characterized by determination coefficient of 0.998, 0.985, and 0.994, quantification limits of 11.28, 2.70, and 3.67 × 10−6 mol L−1 and detection limits of 3.72, 0.89, and 1.21 × 10−6 mol L−1, respectively. A recovery from 72.0 to 128.5% for different concetration ratios of tocopherols has been achieved. This recovery range is in the accordance with values reported for liquid chromatography.

scholarly journals Evaluation of Various Maintenance Strategies for Reliability Assessment of Thermal Power Plants

2017 ◽  
Vol 7 (3) ◽  
pp. 617
Author(s):  
Sima Zarei ◽  
Peiman Ghaedi-Kajuei
Keyword(s):  
Power Plants ◽  
Probabilistic Models ◽  
Thermal Power ◽  
Electrical Power ◽  
Detailed Comparison ◽  
Deterministic Models ◽  
Time Intervals ◽  
Continuous Service ◽  
Deterministic And Probabilistic Approaches ◽  
Selection Of

In recent years, the world has had a phenomenal economic growth due to the acquisition of innovative technologies and globalization. In the meantime, electrical power plants are regarded as a fundamental element in industrial and production, and any deficiency in supplying may lead to significant financial detriment. Regard to the deep dependency of modern lifestyle to electricity, providing a high-quality and reliable electricity for consumers has taken on paramount importance. The reliability of a power plant depends on the configuration of elements and the reliability of each utility. The reliability, continuous service, flexibility in operation, simplicity, maintenance, development availability, meeting required standards etc. constitute the decisive factors for selection of a utility. Hence, each component of a power system must maintain the adequate level of reliability. In general, the maintenance approaches are classified into two parts: 1- The maintenance which must be carried out within determined and specified time intervals; 2- The maintenance which must be performed when required or in emergencies. To evaluate the maintenance and its effect on reliability, two types of deterministic and probabilistic approaches are presented. In this paper, a comprehensive description of both models is issued, and a detailed comparison is drawn. The results obviously show that the probabilistic models have considerable priority to deterministic models regard to their abilities for maximization of reliability or minimization of costs.

The Volvo-Turbo Experimental Gas Turbine

1962 ◽  
Author(s):  
S. O. Kronogard
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Short Description ◽  
Reduction Gear ◽  
Working Cycle ◽  
Power Turbine ◽  
Relative Arrangement ◽  
Selection Of

This paper gives a brief description of the Volvo experimental turbine, its working cycle, its basic components and their relative arrangement as well as some of the basic thinking behind the selection of the same. The paper also gives a short description of the new concept of a dual-geared power turbine, the combined reduction gear and high-speed hydrodynamic retarder, as well as some other new features incorporated.

scholarly journals Selection of integration time intervals for quartz OSL decay curves

2010 ◽  
Vol 5 (6) ◽  
pp. 657-666 ◽  
Author(s):  
Alastair C. Cunningham ◽  
Jakob Wallinga
Keyword(s):  
Integration Time ◽  
Time Intervals ◽  
Selection Of
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