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Protasov A. The professional training features for NDT graduate students

Friday, 22 July 2011 17:31 administrator
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The Non-Destructive Testing (NDT) specialists carry out a quality exam for various kinds of products, conduct inspection of potential accident industrial objects, and provide their safe exploitation. Such branches of industry as aviation, ground transportation, nuclear power stations, and civil engineering can’t even exist without NDT specialists. All people need high quality products, to be protected from terrorism and technogeneous catastrophes. Thus, NDT specialists are desired in any society. Today Ukraine has a lot of objects and constructions which were built many years ago. Such objects as hydroelectric plants, dams, bridges, inflammable stores, and many others need to be inspected for evaluation of their safety. So, the problem of NDT specialist preparation is very important for Ukraine which had Chernobyl catastrophe in the past.

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Last Updated on Friday, 22 July 2011 17:34
 

Protasov A., Gordienko Y., Zasimchuk E. Multilayer thin film sensors for damage diagnostics

Friday, 22 July 2011 17:15 administrator
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The new innovative approach to damage diagnostics within the production and maintenance/servicing procedures in industry is proposed. It is based on the real-time multiscale monitoring of the smart-designed multilayer thin film sensors (MTFS) of fatigue damage with the standard electrical input/output  interfaces which can be connected to the embedded and on-board computers.

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Protasov A., Ongirska N., Eremenko V. Electronic devices

Wednesday, 21 September 2011 10:45 administrator
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“Electronic devices” is the main subject in students training to be experts in electronics. Students need a good knowledge in the solid-state physics, contact phenomenon, and circuit theory to study “Electronic devices”. The main task of this subject is to teach students to use various tips of modern semiconductors and integrated circuits in different function devices.

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Protasov A., Sineglazov V. Estimation of defects geometric parameters with a thermal method

Friday, 22 July 2011 17:50 administrator
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The problem of estimation of flaws' parameters has been realized in two stages. At the first stage, it has been estimated relationship between temperature difference of a heated sample's surface and geometrical parameters of the flaw. For this purpose we have solved a direct heat conduction problem for various combination of the geometrical sizes of the flaw. At the second stage, we have solved an inverse heat conduction problem using the H - infinity method of identification. The results have shown good convergence to real parameters.

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Sokurenko V., Molebny V. Damped least-squares approach for point-source corneal topography

Saturday, 23 July 2011 14:24 administrator
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An optimization algorithm to be used in point-source corneal topographers is developed for the reconstruction of the topography of aspheric corneal surfaces. It is based on the damped leastsquares technique. The reconstructions obtained with a topographer comprising 48 or 90 point sources for corneas having different forms (spherical, conicoidal, complex) and apical radii (5–16 mm) were simulated numerically. Zernike polynomials up to the seventh radial order were used for the description of the shape of the anterior corneal surface. With no noise, i.e. uncertainty in the position of the image of each object point, it is shown that this approach allows reconstruction of the surface with a root-mean-square (RMS) error of <5 · 10^7 lm for the elevation map and 3 · 10^7 diopter for the refraction map. With noise, to get an averaged surface elevation RMS error of <1 lm, or an averaged refraction RMS error of <0.25 diopter, each spot must be located (in the image plane) with an error <1 lm.
Keywords: cornea, elevation map, least squares, point source, refraction map, topography.

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Last Updated on Saturday, 23 July 2011 14:26
 

Tymchik G., Diorditsa I., Murakhovskyy S., Tymchik R. Co-ordinate position of sensor in mass of cutting tool

Thursday, 22 November 2012 11:51 administrator
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Tymchik G., Diorditsa I., Murakhovskyy S., Tymchik R. Co-ordinate position of sensor in mass of cutting tool. – XIV International PhD Workshop OWD 2012, 20–23 October 2012.

Mathematical research which leads to is considered in the article, necessity of location of sensor in the direction of maximal action of vibroacoustic wave in-bulk toolpiece for the receipt of effective informative signal from the area of metal-workingness.

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Last Updated on Monday, 30 March 2015 09:12
 

Tymchik G., Filippova M., Demchenko M. Correcting the position of piezoelectric transducers during acoustic control of the stressed-strained rolled sections

Wednesday, 02 November 2016 08:59 administrator
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Tymchik G., Filippova M., Demchenko M.  Correcting the position of piezoelectric transducers during acoustic control of the stressed-strained rolled sections

With the increasing pace of construction, there is a growing need for the development and use of new methods and means to ensure their integrity, reliability, performance efficiency, safety, which will make it possible to conduct in a short time diagnostics of critical elements of constructions.The main indicator of technical condition of a building, which is responsible for its performance, is the stressedstrained state (SSS) of structural elements. As the bearing elements of modern buildings of civil and industrial purpose, metal structures (MS) are used, made of welded and rolled shaped sections (SS) [1–4].
All structural elements of steel SS of MS work on bend. Maximum values of stress occur in places of the largest bend. To provide for reliability, when designing MS, the permissible values of stresses are calculated that would not lead to the occurrence of critical stresses in the areas of maximum concentration. However, a change in SSS of a building’s MS is caused by several factors: change in the purpose of a facility, reorganization of a technological process with a change in technological lines in the building, operation of facility beyond the limits of design modes, natural disasters, and changes in regulatory requirements. 
To ensure integrity of a structure, it is necessary to carry out current control of the technical condition by identifying real values of the stresses in places  of their concentration [5, 6]. Therefore, of particular importance is the development of operational methods of non-destructive control, which would allow diagnosing the value of SSS of SS with high reliability.
The relevance of the work is in a comprehensive study of the impact of SSS and the SS geometry on the change in the measurement base for the entire nomenclature row of SS, which will enable designing means for diagnosing SSS of SS under operation conditions.
Keywords: piezoelectric transducer, stressed-strained, structural element,  stressedstrained state, acoustic testing

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Last Updated on Wednesday, 02 November 2016 09:18
 

Tymchik G., Filippova M., Demchenko M. Analysis Of Acoustic Diagnostics Errors Of Stress State For Shaped Profiles Of Metal Structures

Thursday, 20 October 2016 10:18 administrator
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Tymchik G., Filippova M., Demchenko M. Analysis Of Acoustic Diagnostics Errors Of Stress State For Shaped Profiles Of Metal Structures

Abstract. The article is devoted to analysis of the errors that occur when acoustic diagnostics of stress state for shaped profiles of metal structures. The analysis of methods for acoustic diagnostics of stressed state of shaped profiles was conducted using mirror-shadow method and areas, causing the occurrence of errors, were revealed. The analysis of tool, methodical and subjective errors that accompany acoustic diagnostics of stress state of shaped profile allowed offering recommendations for their reduction and increasing the reliability of diagnostics results. The necessity of reducing the total error for determining the stress state caused by factors accompanying acoustic diagnostics of shaped profiles was shown. Application of automation during the acoustic diagnostics of stress state for shaped profiles of metal structures was proposed. This will significantly increase the reliability of the data by reducing human intervention in the process of measurement and processing results. Technical and methodological solutions were proposed that will reduce the impact of the total error on the result of acoustic diagnostics of stress state for shaped profiles using the mirror-shadow scanning method.
Keywords: total error, acoustic diagnostics, stress state, shaped profiles.

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Tymchik G.S., Diorditsa I.M., Skytsyuk V.I., Vysloukh S.P., Diorditsa A.M. Determination Of Cylindrical Shape Parts With Solid Processing In Automatic Mode

Saturday, 12 November 2011 15:13 administrator
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Tymchik G.S., Diorditsa I.M., Skytsyuk V.I., Vysloukh S.P., Diorditsa A.M. Determination Of Cylindrical Shape Parts With Solid Processing In Automatic Mode. ­– XII International PhD Workshop OWD 2010, 23-26 October 2010

The article is devoted to problems associated with geometric precision production cylindrical parts on lathes with systems of CNC. The possibility of a high view of cylindrical shapes using a complex adaptive system working process.

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Tymchik G.S., Diorditsa I.M., Skytsyuk V.I., Vysloukh S.P., Diorditsa A.M. Research of Properties of Surface of Detail

Thursday, 26 March 2015 09:58 administrator
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Tymchik G.S., Diorditsa I.M., Skytsyuk V.I., Vysloukh S.P., Diorditsa A.M. Research of Properties of Surface of Detail. – Innovations and Technologies News, Nr.3(11), 2011, Latvia.

The article is devoted to problems associated with geometric precision production cylindrical parts on lathes with systems of CNC. The possibility of a high view of cylindrical shapes using a complex adaptive system working process.

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Last Updated on Friday, 27 March 2015 12:07
 
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