Increasing the efficiency of non-destructive control of lamellar materials with single and double-layer structure is an urgent scientific and technical task. The aim of the work was to investigate the peculiarities of excitation and reception of plate waves (PW) in single-layer and two-layer materials by pulsed laser radiation in relation to detection of cracks in them and estimation of layer thickness at one-sided sounding. A methodology has been developed and experimental studies of the influence of moving the area of laser generation of PW over the surface of dural samples relative to the crack simulator of different depth with the subsequent reception of the signal at a characteristic angle of inclination have been carried out. A significant change in the structure of the wave front at localization of the moving wave source zone in the vicinity of the crack simulator was found, accompanied by a change in the ratio of extreme values of amplitudes of the received asymmetric mode A^extr up to 14–15 dB. At receiving the symmetric s₀ mode the value of A^extr does not exceed 3–4 dB. The interpretation of this effect is given. A method and scheme of thickness measurement of twolayer materials with metallized coating and non-metallic base (glass-textolite) is proposed and developed, where samples with copper coating and glass-textolite base of different thickness are used as an example. In this case, the velocity or propagation time of PW, between two small aperture (non-directional) transducers with an acoustic base of 43 mm, is used as an informative parameter. In this case, the estimated sensitivity of the measured circuit to changes in the thickness of the metal coating is of 0.5 μm, and the base – twice as much.

The topic of research stands on heavy liquid metal coolants is currently undergoing a rebirth. Experimental stands have been built, for example, LILLA SCK CEN (Center for Nuclear Research in Belgium, Mol). This is one of the most famous stands that uses heavy liquid metal heat carriers. But a sufficiently complete description of the equipment line-up and the application of specific solutions for monitoring and maintaining the operability of the stands at the heavy liquid metal coolants is not published in the open press. Most likely, this is due to the specifics of research where there is a sufficient amount of secrecy. The aim of the work was to conduct a comprehensive review of various equipment use in this field. This will make it possible to plan more efficient composition of new research stands at heavy liquid metal coolants and avoid unnecessary mistakes when operating them. Heavy liquid metal heat carriers of nuclear power plants such as lead, eutectic lead-bismuth alloy, lead-lithium, gallium alloys differ significantly in their physicochemical properties from traditional and well-studied, widely used water, sodium, as well as liquid salt heat carriers, potassium, gases (helium, etc.).

Development of rifle electronic simulators (i.e. for hand weapons and not using ammunition) is an important task, since the production of any type of small arms according to regulatory documents also requires the production of a simulator to instill aiming and firing skills. A family of electronic shooting simulators "STrIzh" of four levels of implementation: initial, basic, professional and special is described. Structural diagrams of different configurations are given, functional purpose and capabilities of each level of simulators are shown. The initial level allows independent assemble the simulator from publicly available elements (laptop, webcam, weapon layouts, IR LEDs), which can contribute to widespread use both in schools and at home, but is low in accuracy and manufacturabili (requires daily calibration). The basic level also allows independent assemble the simulator, and less publicly available elements (laptop, projector, mockup weapons, laser emitters, FHD camera), which allows to be used both in schools and in DOSAAF structures, and has acceptable accuracy and manufacturability (a weekly calibration is enough, but assembling a mock-up weapon with laser emitters requires adjustments). It is recommended to limit the special level to virtual reality simulators, including a helmet with a smartphone and a mockup of a weapon with its smartphone which also contributes to its public availability and widespread use. The simulator software algorithm should fully support all implementation levels with different configurations and include a multimedia shooting training system. Mathematical models of external ballistics of thrown equipment for Kalashnikov assault rifle, Makarov pistol, hand-held anti-tank grenade launcher 7 products are described in detail, taking into account changes in atmospheric factors (temperature, air pressure, wind force) and dispersion of various types of ammunition. The above review of rifle simulators and their experience revealed the main trends of improvement – use of virtual reality and training not only direct shooting skills, but also training in the eligibility of the use of weapons, safe handling of them and even tactical interaction in the group.

Results of use of the laser beam deflection technique for determination of thermo-optic coefficients (TOCs) of the Er³⁺-doped gadolinium-yttrium oxyorthosilicate crystal (Er³⁺:(GdY) SiO
– Er:GYSO) are presented. A 0.1 at.% Er-doped gadolinium-yttrium oxyorthosilicate crystal was grown by the Czochralski method under nitrogen atmosphere. Raw materials such as Er₂O₃, Gd₂O₃, Y₂O₃, and SiO₂ were weighed according to the formula (Er_0.001Gd_0.8995Y_0.0995)₂SiO₅. Optical properties of the biaxial Er:GYSO crystal are described within the frame of the optical indicatrix with orthogonal principal axes N_p , N_m , and N_g . To characterize the anisotropy of the TOCs a sample from the grown Er:GYSO crystal was prepared in a shape of a rectangular parallelepiped with dimensions of 7.0 (N_p ) × 8.0 (N_m ) × 8.5 (N_g ) mm³. Each face of the sample is perpendicular to one of the optical indicatrix axes Np , Nm and Ng . For determination of the TOCs the laser beam deflection technique for a material with a linear temperature gradient is used. Measurements are performed at the wavelength of 632.8 nm. The thermal coefficient of the optical path (TCOP) for the Er:GYSO crystal measured at the wavelength of 632.8 nm at different light polarization E and propagation direction k were obtained. The TCOP values are positive for all directions of the light propagation k // N_p , N_m, N_g . This means that the sign of the thermal lens which is directly related to the TCOP value will also be positive, and the positive thermal lens is then expected for N_p N_m-, and N_g-cut Er:GYSO. Applying an analysis of the thermal lensing the dn /dT value for Yb:GYSO is estimated to be 6.5×10^–6 K^–1.

The influence of temperature in the range from 20 to 100 °C on the specific surface energy and fracture toughness of standard silicon wafers of three orientations (100), (110) and (111) was studied. Silicon wafers were heated on a special thermal platform with an autonomous heating controller, which was installed under the samples. At each temperature, the samples were kept for 10 min. The specific surface energy γ after exposure to temperature was determined by atomic force microscopy (AFM). Fracture toughness during and after exposure to temperature was determined by indentation followed by visualization of the deformation region using AFM. It has been established that the specific surface energy γ of Si wafers with orientation (100) and (111) increases with increasing temperature from 20 to 100 °C, and for orientation (110) it increases at temperatures from 20 to 80 °C, and then decreases. The diagonal length d of indentation marks, performed both during the heating process and after heating, decreases by increasing the temperature from 20 to 100 °C. The crack length c decreases on silicon wafers during indentation during heating from 20 to 100 °C, and after exposure to temperature, the length increases. When the plates are exposed to temperature, the fracture toughness K_IC increases with increasing temperature: for orientation (100) – up to 1.61 ± 0.08 MPa·m^1/2, for (110) – up to 1.60 ± 0.08 MPa·m^1/2 and for (111) – up to 1.66 ± 0.04 MPa·m^1/2. A direct correlation was established between K_IC, measured during  exposure to temperature, and an inverse correlation between K_IC measured after exposure to temperature and specific surface energy for the (100) and (111) orientations. An inverse correlation was obtained by K_IC at the (110) orientation when exposed to temperatures of 20–40 and 80–100 °C, and after exposure, a direct correlation was obtained. At 60 °C there is no correlation. The results obtained can be used to improve the mechanical properties of silicon wafers used in solar cells and microelectromechanical systems (operating at temperatures up to 100 °C).

Monitoring of air pollutions is one of actual trends in the development of industrial and domestic instrumentation. There are sets of tasks for improving gas analytical instruments because of increasing demand for control of a concentration of explosive and toxic gases on a level with maximum allowable concentration. The aim of the paper was to investigate the methods of formation and elemental composition of indium oxide films modified with tin oxide on the surface of gas sensor elements as one of the promising compounds for improving the detection efficiency of explosive and toxic gases in the environment. The processes of formation of gas-sensitive films deposited on the surface of nichrome alloy information electrodes were studied in this article. Substrates of anodic aluminum oxide with area of 10 × 10 mm2 and a thickness of 45 ± 0,5 μm were chosen for research. Two layers on the surface of the samples were formed. The first layer was formed from NiCr alloy (Ni – 80 %, Cr – 20 %) with a thickness of ≈ 0.3 μm by ion-plasma sputtering. The second layer was based on indium oxide with addition of tin oxide with thicknesses from ≈ 0.3 μm to ≈ 1.0 µm and coated with sol-gel technology. Five samples of gas-sensitive films were formed with different methods of deposition and heat treatment. Scanning electron microscopy was used for study of films’ morphology and elemental compositions of samples. The most perfect continuous semiconductor films were obtained by multilayer applying of a sol-gel paste. When semiconductor films were processed at annealing temperatures of 700 °C and higher in vacuum so there was observed cracking of semiconductor films up to a layer of NiCr alloy. The developed surface of gas-sensitive films allows to reach high sensitivity and affectivity of semiconductor sensors for control of air gas composition.

Innovative production technologies, such as additive synthesis, is inextricably linked with the development of methods for assessing the quality of manufactured products. At the initial stage of introducing of new production methods into various industries, the most studied and widely used control methods are usually used. In most cases these are standard destructive tests. As an alternative to standard tensile tests used to evaluate the elastic and strength properties of polymer products produced using SLA-technology, the dynamic indentation method is studed in this work. Using the samples of the high-temperature photopolymer resin High Temp RS-F2-HTAM-01, the possibility of optimizing 3D printing methods and post-processing modes based on dynamic indentation data is shown. It has been shown that non-pigmented photopolymers are most susceptible to embrittlement due to their ability to transmit UV radiation into the volume of the synthesized material. It was found that the embrittlement of a polymer material has a lesser effect on the result of measuring its dynamic hardness than on its tensile strength. It has been established that post-curing of polymer products at high temperatures (up to 160 °C) and UV radiation with a power of 39 W can increase their strength and elastic modulus by 170 % and 85 %, respectively, compared to the state before treatment. It has been proven that the sensitivity of the dynamic indentation method to changes in the physical and mechanical characteristics of products obtained using SLA-technology under various types and modes of their post-processing is comparable to the sensitivity of standard tensile tests.

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