scholarly journals REVEALING CHANGES IN THE SPACE OBJECTS MOTION DESCRIBED BY AUTOREGRESSIVE MODELS

2021 ◽  
Vol 2 (133) ◽  
pp. 79-88
Author(s):  
Oleksandr Sarychev ◽  
Bogdan Perviy
Keyword(s):  
Time Series ◽  
Autoregressive Models ◽  
Spacecraft Motion ◽  
Term Operation ◽  
Space Objects

The task of revealing changes in the non-functioning Sich-2 spacecraft motion is completed using autoregressive models and time series of TLE elements. The developed method is recomended to use for revealing changes in the movement of space objects during their long-term operation.

scholarly journals Models of space object motion based on time series of TLE-elements

2021 ◽  
Vol 2021 (1) ◽  
pp. 51-62
Author(s):  
O.P. Sarychev ◽  
◽  
B.A. Perviy ◽  
Keyword(s):  
Time Series ◽  
Mathematical Models ◽  
Statistical Method ◽  
Space Debris ◽  
Launch Vehicle ◽  
Object Motion ◽  
Autoregressive Models ◽  
Space Object ◽  
Space Objects ◽  
Time Determination

Timely detection of changes in the characteristics of space hardware objects during their long-term operation is one of the main tasks in the development and study of onboard systems that maintain the efficiency of their operation. This paper presents a statistical method for simulating the motion of space objects (spacecraft and used launch vehicle stages) in the class of autoregressive models. The method allows one to improve the quality of description and prediction of the motion of space objects based on simulating time series of their TLE-elements (two-line orbital element sets). The purpose of this work is to increase the accuracy of mathematical models of the observed motion of space objects in the problems of deorbit time determination, satellite collision prediction, and space debris cataloging. The paper presents a system for simulating the motion of space objects, which allows one to determine an optimal amount of learning samples in simulating time series of TLE elements, determine the order of autoregression and find an optimal model structure for each variable element, identify model parameters in conditions of unequally spaced observations, identify features of the time behavior of the root-mean-square errors of the constructed autoregressive models on the basis of dividing the initial time series of TLE-elements into successive learning intervals, and obtain predictive estimates of the values of variable elements. The proposed statistical method of space object motion simulation can be recommended to describe and predict the motion of spacecraft and used launch vehicle stages represented as time series of TLE-elements (which are publicly available and regularly updated). The application of the proposed statistical method will increase the accuracy of mathematical models of the observed motion of space objects in the problems of deorbit time determination, satellite collision prediction, and space debris cataloging.

scholarly journals AUTOREGRESSION MODELS OF SPACE OBJECTS MOVEMENT REPRESENTED BY TLE ELEMENTS

2020 ◽  
Vol 2 (127) ◽  
pp. 103-116
Author(s):  
Aleksandr Sarichev ◽  
Bogdan Perviy
Keyword(s):  
Time Series ◽  
Mean Square Error ◽  
Autoregressive Model ◽  
Autoregressive Models ◽  
Mean Square ◽  
Element Determination ◽  
Training Samples ◽  
Space Objects ◽  
The Mean

The developed method, which is a modification of the previously developed methods for constructing autoregressive models, is used to simulate the motion of space objects in the time series of their TLE elements. The modeling system has been developed that includes: determining the optimal volume of training samples in modeling time series of TLE elements; determination of the autoregression order for each variable (TLE element); determination of the optimal structure and identification of the parameters of the autoregressive model for each variable; identification of patterns of evolution of the mean square error of autoregressive models in time based on the modeling of time series of TLE elements according to the principle of "moving interval".

Analysis of crystallite size changes in a hematite and magnetite formed on steel used in the power idustry

2017 ◽  
Vol 1 (21) ◽  
pp. 65-73
Author(s):  
Monika Gwoździk
Keyword(s):  
Elevated Temperature ◽  
Oxide Layer ◽  
Cross Section ◽  
X Ray ◽  
Term Operation ◽  
Diffraction Line Profile ◽  
Crystallite Sizes ◽  
Scherrer Formula ◽  
Pipe Outlet

The paper presents results of studies on the crystallite sizes of oxide layer formed during a long-term operation on 10CrMo9-10 steel at an elevated temperature (T = 545° C, t = 200,000 h). This value was determined by a method based on analysis of the diffraction line profile, according to a Scherrer formula. The oxide layer was studied on a surface and a cross-section at the outer and inner site on the pipe outlet, at the fire and counter-fire wall of the tube. X-ray studies were carried out on the surface of a tube, then the layer’s surface was polished and the diffraction measurements repeated to reveal differences in the originated oxides layer.

Retention and expression of recombinant plasmids in suspended and biofilm-bound bacteria degrading trichloroethene (TCE)

1997 ◽  
Vol 36 (10) ◽  
pp. 1-8 ◽  
Author(s):  
James D. Bryers ◽  
Robert R. Sharp
Keyword(s):  
Biofilm Reactor ◽  
Bacterial Biofilm ◽  
Laboratory Evaluation ◽  
Recombinant Bacteria ◽  
Suitable Host ◽  
Term Operation ◽  
Open Environment ◽  
Recombinant Microorganisms ◽  
Extracellular Polymer

Exposure of plasmid recombinant microorganisms to an open environment, either inadvertently or intentionally, requires research into those fundamental processes that govern plasmid retention, transfer and expression. In the open environment, a majority of the microbial activity occurs associated with an interface, within thin biological layers consisting of cells and their insoluble extracellular polymer, layers known as biofilms. Current toxic wastewater or wastegas treatment reactors exploit bacterial biofilm systems for certain system operating advantages. Using recombinant bacteria within a biofilm reactor to degrade xenobiotic wastes requires finding a suitable host to harbor and express the desired plasmid phenotype. Suitable host characteristics include: the ability to produce copious amounts of biofilm, resistance to waste-related injury and toxicity, and the ability to retain and express the desired plasmid during long term operation. This paper reports on a laboratory evaluation of factors governing plasmid retention and the expression of trichloroethene (TCE) degradative capacity in both suspended and biofilm cultures.

Restoration of cylinder liners for automotive tractors engines in modern conditions

2020 ◽  
pp. 122-133
Author(s):  
Vyacheslav A. Denisov ◽  
Aleksandr Yu. Kostyukov ◽  
Roman N. Zadorozhniy
Keyword(s):  
Adhesion Strength ◽  
Electrode Materials ◽  
Research Purpose ◽  
Laboratory Studies ◽  
Term Operation ◽  
Operational Load ◽  
Operational Tests ◽  
Conducting Research ◽  
Cylinder Liners

One of the most promising technologies for restoring machine parts and cylinder liners is electric spark treatment as the most versatile technology that provides high-quality restoration of worn parts with wear up to 0.5 mm. (Research purpose) The research purpose is in developing a technology for restoring various cylinder liners by means of electric spark processing, selecting optimal modes and electrode materials that allow improving the quality of repair and increasing the post-repair life of the sleeve. (Materials and methods) It was taken into account when conducting research aimed at restoring the geometric parameters of the sleeve, that the coating must have sufficient adhesion strength to the surface of the sleeve under mechanical, thermal loads and long-term operation. Laboratory studies of the adhesion strength of electric spark coatings on the separation (adhesive) and on the cut, as well as tribotechnical studies of interfaces were conducted. Authors have found by analyzing the results of operational tests of restored and new cylinder liners the prospects for using electric spark treatment of worn parts, including diesel engine liners. (Results and discussion) It was shown by laboratory studies of the adhesion strength of electric spark coatings with a 0.2 mm thick BrMKc 3-1 electrode to the working surface of cylinder liners that their separation strength (adhesive) was 20-40 megapascals, and the shear strength (cohesive) was 50-80 megapascals. It was found that this provides the required functional strength of coatings with maximum operational load. The article presents the results of comprehensive research in graphs and tables. (Conclusions) The research conducted in the CCP "Nano-Center" of the FSAC VIM and operational tests in the 2nd bus fleet of Moscow confirmed the principal possibility of effectively restoring cast iron liners (blocks) using the technology of electric spark processing.

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