The existing methods only allowed to determine the dynamic or average characteristics of specific copies of gas temperature sensors as the airflow test results of a limited number of specific copies of gas temperature sensors were carried out on a certified airflow equipment. The actual operating conditions of aircraft gas temperature sensors significantly differ from those at airflow equipment. The aim of the study was to develop methods of recalculation of a test results of a limited number of gas temperature sensors that were received at certified airflow equipment and to get nominal dynamic characteristics of a particular type of gas temperature sensors in the anticipated operating conditions.

This study offers the algorithm for the identification of the nominal dynamic characteristics of gas temperature sensors that are used to measure the temperature of gases in aircraft gas turbine engines. The algorithm makes it possible to 1) register the transient characteristics of gas temperature sensors of a particular type at a predetermined rate of air flow, 2) calculate the heat transfer coefficient between the gas temperature sensors and the air flow at each airflow rate, 3) measure the average transient characteristics of the gas temperature sensors at each airflow rate, 4) set the parameters of the hyperbolic function of the nominal variables of the time constants of selected gas temperature sensors from the heat transfer coefficient. The heat transfer coefficient is calculated based on the expected operating conditions of the gas temperature sensors.

The result of the study was that the parameters of the hyperbolic function of the nominal variables of the time constants for the dynamic model of the second order gas temperature sensors were found. The developed method makes it possible to predict the dynamic performance of the specific types of gas temperature sensors in the expected operating conditions. 

The point optical smoke detector is currently the most effective means of fire detection at the early stage of its occurrence. The urgent task for this type of detector is to increase its sensitivity to «black» smoke and ensure resilience to the effects of electromagnetic interference and particle smoke origin.The objective of this work is to develop a structure and algorithm of point combined fire detector that provides high sensitivity to various types of fumes, detection rate and high noise immunity.

 The decision of the current objective is carried out using the proposed optical scheme of the dual-channel devices of smoke detection (for control of the radiation intensities scattered by smoke particles and passed through the smoke).

The design and algorithm of the combined fire detector comprising a dual-channel laser device of smoke detection and carbon monoxide detector is developed.

The results of the made detector tests indicate about its increased in comparison with the conventional single-channel point smoke fire detector sensitivity to various types of fumes and detection rate of fires. The high functional characteristics of the detector are provided with application additional channel of smoke detection (to intensity change of transmitted radiation through it) created by the requirements for unrestricted entry of smoke in the area of control and effective algorithm for processing of recorded signals. 

Today facilities with collimated radiation field are widely used as reference in metrological support of devices for neutron radiation measurement. Neutron fields formed by radionuclide neutron sources. The aim of this research was to study characteristics of experimentally realized neutron fields geometries on АТ140 Neutron Calibration Facility using Monte Carlo method.

For calibration, we put a device into neutron field with known flux density or ambient equivalent dose rate. We can form neutron beam from radionuclide fast-neutron source in different geometries. In containercollimator of АТ140 Neutron Calibration Facility we can install special inserts to gather fast-neutron geometry or thermal-neutron geometry. We need to consider neutron scattering from air and room’s walls. We can conduct measurements of neutron field characteristics in several points and get the other using Monte Carlo method.

Thermal neutron collimator forms a beam from radionuclide source with a significant amount of neutrons with thermal energies. From found relationship between full neutron flux and distance to neutron source we see that inverse square law is violated. Scattered radiation contribution into total flux increases when we are moving away from neutron source and significantly influences neutron fields characteristics. While source is exposed in shadow-cone geometry neutron specter has pronounced thermal component from wall scattering.

In this work, we examined main geometry types used to acquire reference neutron radiation using radionuclide sources. We developed Monte Carlo model for ²³⁸Pu-Be neutron source and АТ140 Neutron Calibration Facility’s container-collimator. We have shown the most significant neutron energy distribution factor to be scattered radiation from room’s walls. It leads to significant changes of neutron radiation specter at a distance from the source. When planning location, and installing the facility we should consider radiation quality requirements. 

In carrying out eddy current thickness measurement of two-layer conductive objects one from the interfering factors is the presence of variations in the value of the electrical conductivity of the material of the upper layer (coating) when moving from point to point on the surface of object of control or when passing from one object of control to another. The aim of this work is to evaluate the accuracy of determining the thickness of the conductive coating disposed on a conducting ferromagnetic basis, using the phase method of eddy current testing. The reason of the error is variation of the electrical conductivity of the material of coating.

Determination of the error is based on calculations using known analytical expressions for the loop with current of sinusoidal form arranged over the infinite half space with a covering as a thin layer. Selected in calculating electromagnetic parameters of coating and substrate approximately correspond to the case -chromium layer on a nickel base. Calculations are performed for different frequencies of current passed through coil.

It is shown that at reduction of frequency of the current passes through the coil the error is reduced. The value of the lowest possible operating frequency of the excitation current is determined by the condition of absence influence on the phase introduced into the superimposed transducer emf variations in the thickness of the basis.

To reduce the indicated error it is proposed to determine, on the basis of phase method at a relatively high frequency transducer current excitation, conductivity of the material of coating. After this, at a low frequency excitation current and using phase method, the coating thickness is determined, taking into consideration the previously determined value of the conductivity of coating. Also discussed ways to improve the accuracy of phase measurements in the MHz region of the excitation current frequency. 

Classification of technical means of physical exercise and sport taking into account the current state of sports science is one of the important tasks that allow planning the development of promising trends in training equipment technologies. Existing approaches to grouping technical means of physical training do not adequately take into account the biomechanical regularities of structuring exercises and their effectiveness. The aim of this work was to build a new approach to the classification of such devices taking into account the regularities above.

The article suggests the system of grouping means of physical training that includes picking out biomechanically substantiated levels of physical exercise structuring (psycho-informational, physiological and mechanical levels) as final targets, similar input levels of impact and the appropriate means. As a result, digital indexing of the above targets was proposed which allows to group and present the technical means in the form of matrix depending on the combination of the indexes and to determine promising trends in novel developments finding the blank areas in the matrix

In accordance with the proposed classification by the example of technical means of strength training, the concept of the biomechanical efficiency of the devices is introduced for the first time, for which specific numerical coefficients were introduced such as spatiality, inertia and energy dissipation.

The paper presents a qualitative analysis of the typical means of strength training in terms of biomechanical efficiency, which showed the prospect of engineering technical devices with many degrees of freedom using the friction method of creating the resistance when training.

Mass-production of different laser systems often requires utilization of the focal spot size method for determination of output laser beam spatial characteristics. The main challenge of this method is high accuracy maintenance of a CCD camera beam profiler in the collecting lens focal plane. The aim of our work is development of new method for placing of photodetector array in the collecting lens focal plane with high accuracy.

Proposed technique is based on focusing of several parallel laser beams. Determination of the focal plane position requires only longitudinal translation of the CCD-camera to find a point of laser beams intersection. Continuous-wave (CW) diode-pumped laser emitting in the spectral region near 1μm was created to satisfy the requirements of the developed technique. Designed microchip laser generates two stigmatic Gaussian beams with automatically parallel beam axes due to independent pumping of different areas of the one microchip crystal having the same cavity mirrors.

It was theoretically demonstrated that developed method provides possibility of the lenses focal plane determination with 1 % accuracy. The microchip laser generates two parallel Gaussian beams with divergence of about 10 mrad. Laser output power can be varied in the range of 0.1–1.5 W by changing the pumping laser diode electrical current. The distance between two beam axes can be changed in the range of 0.5–5.0 mm.

We have proposed method for determination of positive lens focal plane location by using of CCDcamera and two laser beams with parallel axes without utilization of additional optical devices. We have developed CW longitudinally diode pumped microchip laser emitting in the 1-μm spectral region that can be used in the measuring instrument that doesn’t require precision mechanical components for determination of focal plane location with 1 % accuracy. The overall dimensions of laser head was 70 × 40 × 40 mm3 and maximum power consumption was 7W per one laser beam. 

The aim of the present work is the theoretical justification of new refractive index determination technique for a homogeneous transparent plane dielectric layer. It uses intensity measurements for two polarizations of transmitting electromagnetic beam and does not take into consideration phase relationships and phase parameters of testing field at unknown thickness of a layer.

For this purpose, the layer transmission energy coefficients for two linear polarizations of an electromagnetic beam, orthogonal and parallel to the plane of incidence, are studied to be dependent on the layer thickness and its refractive index. We have found the function of energy transmission coefficients for these polarizations, which does not depend on the layer thickness and is characterized bIt is shown that this function provides the opportunity to determine the layer refractive index uniquely. It can be made analytically using the inverse function, and also with the help of experimental calibration technique for the initial function. The influence of losses on the method efficiency is investigated, and it is established, that the presence of absorption causes appearance of separated zones of refractive index variation, where the method becomes inoperative. However, at absorption index values of the order of 10–5 the method can be applied, but in the bounded domain of refractive index variation.

So, it is established that the proposed methods provides the opportunity to determine the refractive index of a plane dielectric layer under conditions of low and null value of absorption using the intensity measurements for two orthogonal polarizations of transmitting electromagnetic radiation. 

Currently, the use of probe electrometry in non-destructive testing is constrained by the complexity of measurement results interpretation. An output signal of electrometric probe depends on a number of physical and chemical parameters of surface including chemical composition variations, stresses, dislocations, crystallographic orientation of a surface, etc. The study aims to the use of probe electrometry methods for nondestructive testing and analysis of precision metal surfaces’ defects after different treatment or processing.

Control of surface defects of aluminum and its alloys was performed with a scanning Kelvin probe technique. The results of scanning were plotted in a form of contact potential difference (CPD) distribution map. Additionally, a histogram of CPD values distribution and statistical characteristics including the expectation of CPD mean value and histogram half-width were calculated either for the whole distribution or for each individual mode in a case of multimodal distribution.

The spatial CPD distribution of A99 aluminum and AMG-2 alloy surfaces after electrochemical polishing and diamond finishing was studied. An additional study was held for AMG-2 surface after the formation of 30 microns thick specific nanostructured alumina oxide surface layer. Higher quality surfaces have characterized as more homogeneous distribution of the physical properties (at half-width distribution histogram). Surfaces with higher mechanical strength and overall better mechanical properties found to have lower CPD values that correspond to higher electron work function and surface energy. The presence of the second mode in the CPD distribution histogram indicates the significant proportion of defect areas on the sample surface.

Analysis of visualized CPD distribution maps using defined criteria allows detecting and characterizing such defects as residual stress areas, areas with reduced microhardness, surface contamination spots, corrosion defects. This provides the possibility of rapid nondestructive testing and diagnostic of precision metal surfaces, in particular the starting substrates for sensitive elements and sensory devices manufacture. 

One of the main factors affecting the efficiency of oncology patients radiation therapy are time parameters (the amount of time that a patient spends in the therapy room) of the patient exposure session, because the patient treatment position depends on them, and thus the accuracy of delivery of the prescribed dose distribution too. The objective of this work was to define components that influence on the treatment session and to develop an algorithm that allows to determine the duration of the patient treatment sessions with the use of different methods of radiotherapy and tumor localization.

In order to determine radiation therapy session components, that cause the dominant influence on the session timing, the authors carried out a retrospective analysis of each fraction of the total sample of cancer patients treatment plans with most often irradiated with the use of linear accelerators in the NCCB localizations of tumors (more than 5200 fractions).

The appropriate algorithms were designed to assess the results of the analysis of time parameters of radiation therapy oncology patient session during its pre-radiation preparation. It allowed to take into account the individual characteristics of radiation treatment for each irradiation techniques that are the most useful in clinical practice of NCCB radiotherapy department.The components of radiation therapy sessions that caused dominant influence on session characteristics using methods of three-dimensional conformal radiation therapy (3D CRT), intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) were identified.

The characteristics of the linear accelerator and the irradiation plan that influenced the duration of these components (number of radiation fields, dose affecting devices placement, treatment table rotation, treatment field irradiation duration, verification of patient positioning, treatment parameters initialization) were defined. Average exposure time is established for each of the examined methods of radiotherapy and localizations of tumor (from 4 to 8 min for 3D CRT, from 4 to 8 min for IMRT for 3 to 4 min for VMAT). 

The productivity of researchers, as well as the value and quality of scientific publications are considered as properties that indicate the efficiency of the research activities of an organization. The purpose of the present work was to perform a bibliometric study of productivity of Belarusian National Technical University (BNTU) researchers and of the value and quality of their publications. The study as a whole was aimed at assessing the efficiency of research activities of the BNTU.

With the use of the Web of Science and Scopus databases we examined the productivity of the authors in 2011–2015 (including chronological structure of publications and their journal and publishers distributions, data on scientific cooperation, etc.), determined the average citedness of an article; the number of articles included in the 10 % most cited publications in the world in different subject areas of science and also the magnitudes of the «normalized citation» (the latter being compared with the ones for other universities)

The growth of number of published articles and the high value of publications of the University were detected (as reflected in the Web of Science database), as well as the high value of a number of publishing journals. The obtained data as a whole attests to the leading role of laser specialists of the BNTU, and the productivity data attests to the Instrumentation Engineering Faculty as making the greatest contribution to the publications of the BNTU published in the most authoritative sources.

The results of the study attests to a fairly high efficiency of research activities of the BNTU. A significant contribution to improving the mentioned efficiency are being made by the promotion of the University journals to the world information networks and by facilitating the creation of «visibility» of the specialists of the BNTU and the results of their research in the world information networks.