Marine plankton is a key component of aquatic ecosystems. Development of modern and accessible tools for studying planktonic organisms is a relevant and important task. Aim of the study was to develop a device that would be highly accessible and useful for researchers of marine plankton. A prototype of a lensless microscope with an original design that utilizes digital holographic microscopy to visualize marine plankton is presented. Combination of an FDM-manufactured frame, a minimal set of optical and electronic components, and the ability to use open-source software makes it a viable alternative to conventional microscopes for studying planktonic organisms. The device is designed to work with both standard microscope slides and a flow cell, enabling automated sample processing and rapid analysis while, preserving the sample for subsequent conservation and in-depth examination using standard methods.

One of the key problems in the operation of fast neutron reactors cooled by a heavy liquid metal coolant is the formation and accumulation of various deposits. These deposits complicate the process of equipment restoring during repair work. This leads to a shorter work life and a lower efficiency of the equipment as a whole. Except of core destruction cases, the processes of formation and movement of impurities in a circuit with a heavy liquid metal coolant proceed rather slowly over time. So that time from request to receiving of complete information about the system status is an important aspect of its work. The purpose of the work was to control the composition, quantity and condition of impurities in all possible states (present as a solution in the heavy liquid metal coolant, passivated conglomerates on the inner surfaces of the contour, as well as on the free surface of the heavy liquid metal coolant). As well as the development of a set of devices that allows controlling of these processes. The paper considers the processes of mass transfer in the circuit, taking into account the influence of the resulting impurities affecting the state of the system. Sectoral control systems are proposed for use, which make it possible to quickly and reliably monitor impurities and their composition

A mathematical model of a passively Q-switched solid-state laser based on ytterbium and erbium codoped active media with transverse pumping by linear laser diode arrays has been developed. The gain in the laser is calculated using rate equations taking into account the space-time dependence of the pump radiation intensity in the laser element. The output laser characteristics, the pulse energy, the peak pulse power and the pulse duration, are calculated using analytical equations obtained for a passively Q-switched solid-state laser in the approximation of a "slow" saturable absorber. The model allows one to find the range of parameters of the active element, passive modulator, resonator, and pumping system at which the generation threshold is reached and the laser generates pulses with the required energy and duration. Modeling results were used for the experimental development of lasers with an active element based on phosphate glass doped by ytterbium and erbium ions. The energy and duration of the output light pulses were ≈ 1 mJ, ≈ 40 ns, and ≈ 2 mJ and ≈ 20 ns, depending on the content of ytterbium and erbium ions in the active element, as well as on the initial transmission of the passive modulator and the resonator parameters.

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The article describes experience of practical application of the differential thermoelectric tester "THERMO FITNESS TESTING". Description of the sensor design and results of differential thermoelectromotive force measurement for a large group of metals widely used in Russia are given. Usage of the "THERMO FITNESS TESTING" device to test the quality of R6M5 steel heat treatment is described. Dependence of thermoelectromotive force on the heating temperature which can be used for practical purposes was obtained. Usage the "THERMO FITNESS TESTING" to measure the thickness of a cemented (carburized) layer of 12KH2N4А steel is considered. Dependence of the thermoelectromotive force on the thickness of the cementation layer was also obtained.

Crack resistance of two types of glass was studied – cover glass (0.17 mm thick) and slide glass (2 mm thick) using an improved technique through the use of the probe methods, which makes it possible to increase the accuracy of determining the crack resistance of glass. Colorless silicate glass was used. Crack resistance was determined by the Vickers pyramid indentation method. Microstructure of glasses surface and deformation region after indentation were studied using an atomic force microscope. Mechanical properties of glasses were determined by nanoindentation. Surface relief of a glass slide is rougher than that one of a cover glass. Roughness Rz for a cover glass is less than for a slide glass. Specific surface energy value of 0.26 N/m is higher for the slide glass compared to the coverslip. One elastic modulus value E of the cover glass is 48 GPa, and that one of the slide glass is 58 GPa. The microhardness value H is almost the same for by the glasses and amounts to 6.7 GPa for a slide glass and 6.4 GPa for a cover glass. Atomic force microscope images of deformation region after indentation with a Vickers pyramid show that the first cracks appear at a load of 1 N on the slide glass, and at 2 N on the cover glass. At a load of 3 N, the cover glass is destroyed. Based on the results of crack resistance calculations it was found that critical stress intensity coefficient KIC values are 1.42 MPa∙m1/2 for a glass slide, and 1.10 MPa∙m1/2 for a cover glass.

Sources of pulsed photon radiation are widely used in science and industry. In this regard, there is a growing demand for dosimetry instruments capable of operating in these pulsed photon radiation fields. Until now there is no comprehensive methodology that describes the characteristics of reference fields of pulsed photon radiation required for calibration and verification of dosimetry equipment. The aim of this paper was to study the possibility of using a medical linear electron accelerator as a generating source of a reference pulsed photon radiation field. The paper investigates main characteristics of photon radiation field (namely, spectrum and average energy) generated by CLINAC in two modes of operation: 6 MV and 18 MV. Additionally it researches the possibility of attenuation of the CLINAC photon radiation intensity by a lead filter. The spectrum and average energy of the CLINAC photon radiation were calculated by means of Monte Carlo simulation in the Fluka program. The validation of the calculation was determined by comparing the attenuation coefficients calculated by the model with ones obtained experimentally by using real CLINACs. Experimentally, the attenuation coefficients were obtained by measuring the air kerma rate generated by the photon radiation fields of Varian VitalBeam and Varian iX CLINACs at a given point of space. Based on the simulation results, the Ḣ*(10) ambient dose equivalent ratio generated by CLINACs were calculated. It was found that the lead filter effectively attenuates the CLINAC photon radiation in terms of both air kerma rate and ambient dose equivalent rate to levels suitable for calibration of dosimetry equipment designed to measure pulsed radiation. It is shown that the lead filter significantly affects both the photon spectrum of the CLINAC and its average energy.

The highest quality and timely diagnostics of windings’ state of various types of electrical machines including of asynchronous motors’ windings is an impoitant task. Among the existing diagnostic methods currently the most promising are those ones based on methods for analyzing resonance processes occurring in electrical machines. The aim of the article was to assess the possibility of use resonant processes occurring in electrical machines for qualitative diagnostics of their windings state using the asynchronous motors example, to build mathematical models that allow describing defect formation in windings and to analyze the deviation of mathematical models relative to the results obtained.Analysis of the influence of the level of interturn resistances, the number of closed turns and the location of closed turns in sections on the phase-frequency characteristics of asynchronous motors windings of various classes has been carried out. Mathematical models of the phase-frequency characteristics are obtained, coefficients of polynomials are determined and the relative discrepancy between these mathematical dependences relative to the experimental data is estimated depending on the considered parameters characterizing defects in the coils’ windings of electrical machines.Obtained mathematical models and coefficients for them can serve as the basis for construction of automated control and diagnostic systems for checking of the windings state of electrical machines including assessing the residual life of their work.