Modern microelectromechanical systems (MEMS) are devices that incorporate microelectronic components and micromechanical structures on a single chip. Packaging is a mandatory stage in MEMS manufacturing. It ensures mechanical protection, sealing and transmission of electric energy and signals. The present work was aimed at developing a MEMS packaging method as a part of the consolidated manufacturing process. The method is developed on the example of a microwave MEMS switch. The switch manufacturing scheme includes conventional technologies used for producing gallium arsenide integrated circuits: optical lithography, liquid etching, electron-beam and magnetron deposition of metallic, resistive and dielectric films. The work presents a new inter-plate MEMS packaging based on a frame structure with a passivating film. The main purpose of the package frame layer is mechanical support for an upper layer of the sealing material. The frame layer should have the structure allowing for unimpeded removal of the sacrificial photoresist and be impermeable for the sealant. To satisfy the requirements stated, a metallic thin copper-film spatial frame was fabricated by galvanic deposition. The frame structure is a geodesic dome comprised of a complex network of triangle cells arranged in rows. The connected triangles create a self-supporting durable framework. The measurement and modeling results demonstrate that the round frame structure is more durable than a square frame with the same maximum cell dimensions. The stress-strain state for the round framework considerably alters depending on the number of rows of triangle cells. In addition to the mechanical support, the cell structure of the framework – with adequate selection of cell dimensions, solvent and sealant viscosities – allows for unimpeded penetration of the solvent (N-methyl-2-pyrrolidone, NMP) and removal of ma-P1225 photoresist sacrificial layers. At the same time, the layer structure is impermeable for the sealant (benzocyclobutene, BCB). The proposed MEMS switch packaging enables mass fabrication of GaAs integrated circuits in a single process, which expands their frequency range. The new plate-level packaging technology is absolutely compatible with MEMS fabrication technology without specific materials and equipment which reduces the dimensions and cost of MEMS.

Photonic integrated circuits constitute a vital component of contemporary telecommunications systems, facilitating traffic management and reducing energy consumption. However, the integration of these components presents a significant challenge in the form of high polarization sensitivity, which has the potential to limit the overall performance of the device. The objective of this study was to develop a design method and fabrication technology for polarization converters based on silicon nitride-on-insulator. The design of the polarization converters was optimised through the utilisation of finite element method simulations, conducted using the ANSYS Lumerical software. The device features an asymmetric rib waveguide, which facilitates efficient polarisation rotation. The technological implementation comprised plasma chemical vapor deposition of silicon nitride films, three-dimensional laser lithography, and reactive ion etching. A technological assessment determined that the reproducibility tolerance was ± 60 nm. To address this limitation, a mirrored section was incorporated into the polarization converter design, thereby increasing the allowable fabrication tolerance to ± 215 nm without compromising device performance. The optimised polarization converter exhibited a high level of polarization rotation efficiency, reaching 96.3 %, and an output power of 98.32 %. The utilisation of an asymmetric rib waveguide was pivotal in attaining these outcomes, facilitating the transfer of optical power from fundamental transverse electric to fundamental transverse magnetic modes. The incorporation of a mirrored section enhanced the device's manufacturability, maintaining performance despite geometric deviations. These findings highlight the robustness of the proposed design under typical fabrication constraints. This study presents a novel design and fabrication method for silicon nitride on insulator-based polarization converters. The proposed approach improves efficiency and stability. These results provide a foundation for future advancements in integrated photonics, with potential applications in telecommunications and beyond.

In this paper we present the results of the measurements and analysis of particulate emissions of vehicles using the conversion system to use both LPG and gasoline fuels. The vehicles (n = 10) were measured using two different methods at the idle mode. The results show that the total number of particles from LPG-fueled vehicles is 1-1.35 times higher than gasoline-fueled vehicles for both PM2,5 and PM10 in most cases. An increase of the metal components in PM of LPG-fueled vehicles compared to gasoline-fueled vehicles, which might be related to lubricant was observed.

The article presents the results of a theoretical study (literature review of publications), which allowed to establish the negative impact of welding aerosol (manganese and other elements) on the human body: you can use special welder protection equipment (ventilation and individual welder protection); reduce the quantitative and qualitative content of manganese welding aerosols (welding technology, power sources, modern welding materials); reduce the content of manganese in the human body, removing it with medicines. Experimental studies have shown that the use of an inverter power source, compared with a diode rectifier, contributes: to ensuring the drop-by-drop transfer of electrode metal to reduce the time of their formation by 46% and the transition by 28%; ensures the transition of alloying elements from welding materials to the weld metal by 6% and reduces its losses from the fusion line by 6% and HAZ by 3%; to reduce the intensity of education (g / min) SA and their components by 23%; to reduce the specific allocation of CA and their components by 23%.

The paper presents data of experimental research into the importance of protective surface coatings in welded products for MMA stability; heat field distribution patterns on their surfaces, and structure and phase composition of the welded metal. The study has revealed that a protective surface coating in a welded item in MMA has a positive effect on shortcut duration, increasing it by 5-11 %, raising its formation and transformation time by 10-12 %; 15% dimensional increase of a welded metal grain is registered as well, and a heat impact zone expands by 25%.

The study considers the theoretical and technological aspects of the friction units’ resource increasing made of ferritic-pearlitic gray cast iron. It is found that chemical and thermal treatment has the best combination of criteria by the integrated technical and economic analysis for the cast iron parts’ hardening methods. The methods of the cast iron hardening used in practice are not applicable in the real production conditions. It happens because of the technological processes’ complexity and the equipment. Alternatively, the hardened layer thickness does not exceed 0.3 mm. The study considers the main aspects of the new technology application for the surface hardening, The recommendations for its application are formulated. They depend on the intended service of the part. The technical level of the offered solutions is estimated in comparison with traditional technologies of cast iron hardening.

The use of computational methods allows us to significantly shorten the time required for researches and save welding and other consumables. In addition, the computational methods used in studies make it possible to demonstrate the obtained results with a high degree of accuracy. Computational methods are based on computer-aided mathematical modeling of welding processes. Mathematical modeling is applied specifically to develop models adequately describing various welding processes or interrelation between those processes. The article describes the model that demonstrates the distribution of temperature fields in butt joints during the arc welding with pulsed electrode wire feeding.

The paper presents results the research in the effect of power sources dynamic characteristics on stability of melting and electrode metal transfer to the weld pool shielded metal arc welding. It is proved that when applying inverter-type welding power sources, heat and mass transfer characteristics change, arc gap short-circuit time and drop generation time are reduced. This leads to reduction of weld pool heat content and contraction of the heat-affected zone by 36% in comparison the same parameters obtained using a diode rectifier.

Covered-electrode arc welding has been currently widely-spread in assembly and maintenance technologies, as soon as it is a reliable tool, which helps get safe permanent joints in critical structural systems applied in Arctic. It is of burning importance to further enhance accuracy in methods which assess the impact of dynamic properties of power supply equipment with various forms of energy conversion on a consumable electrode welding stability and quality. Literature review [1–11] confirms that objectives, aimed at improving critical (in terms of extreme work and low temperatures) metal structures reliability, demand innovative approaches, i.e.:

A research procedure and configuration of a welded sample are proposed to explore properties of welded metal using thermal microscopy facilities.

A technology of manufacturing surfacing with high-chromium special cast iron without heating is developed; the main directions for improving surfacing quality are outlined. It is proposed to replace manual arc welding with plasma surfacing using high-speed hard surfacing materials.

Experimental research has been carried out to determine quantitative content of solid and gas component of welding aerosol in mechanized gas-shielded welding with constant and pulsewise electrode wire supply. As a result, it has been established that the pulsewise electrode wire supply reduces the release of harmful components of welding aerosol (welding dust СО and SiO2) by 20-25% thanks to lower energy characteristics (the transfer frequency of electrode metal droplets and the time of their exposure to critical temperatures at a short-circuit).

The article presents the results of experimental studies showing that the use of an inverter power supply instead of a diode rectifier provides:: fine-droplet electrode metal transfer which reduces generation time by 46% and transfer time by 28%; transfer of alloying elements from welding materials into the weld metal which reduces its loss from the welding line by 6% and the heat affected area by 3%; reducing the emission rate of welding fumes and their components by 23%; reducing specific emission of welding fumes and their components by 23%.

The paper describes thermodynamic experiments to determine the optimal temperature and time modes for the carbide production process from the briquette charge comprising silica fume and brown coal semi-coke, conditions for chemical enriching of silicon carbide, its phase, chemical and granulometric compositions and particle morphology.

The paper outlines peculiarities of structure formation, phase and chemical composition in regard to heat content in molten electrode metal beads when pipe steel (steel 09G2S) welding using power sources with various energy characteristics. Mathematical calculations indicate an inverter power source provides minor heat content into the bead of electrode metal when welding. Experimental research has pointed at 4-9 % increase in impact strength of joints produced using an inverter power source in comparison with samples produced applying a diode rectifier. The following factors can possibly give rise to the increasing impact strength: difference in microstructures of weld joints, up to 50% shortening ferritic plates in metal of weld joint, change in dimensions of ferritic grains in the heat-affected zone by as much as 17.5 %, and decrease in the extent of heat-affected zone by 50%.

This paper presents peculiar properties of structure formation, phase and chemical composition while welding of low-alloy steel 09MnSi2-1 depending on the dynamic characteristics of power sources of different types. Proper selection of power sources enables to decrease burning of alloy elements in metal of weld (Mn by 14% and Si by 17% of the weight ratio), to obtain more homogenous structure of deposited metal, to reduce length of heat-affected zone by 50% and to improve impact strength by 4-9%.

This work presents peculiarities of forming a structure, phase and chemical composition while welding medium-carbon steels (Steel 45) depending on a heat content of molten electrode metal droplets when using welding power sources having different power parameters. It was experimentally established that the power inverter provides the decreased heat input into droplets of electrode metal during the welding process. This stimulates obtaining a fine-grained structure of the deposited metal and heat affected zone, reduces the extent of the HAZ that enhances working properties of welded joints.

The paper presents the results of studies improve efficiency of manual arc welding of austenitic steels. It is in arc welding of austenite steels the use of inverter power supply furthers obtaining more fine-grained structure of added metal and thermal impact zone, shortens thermal impact zone; that improves corrosion resistance of joint weld.

The given work considers the influence of the power supply type (diode rectifier DR-306 and inverter Nebula-315) upon the chemical composition, microstructure, mechanical properties of weld joints and upon health characteristics of the manual arc welding process.It has been ascertained that the power supply type has a significant influence upon the weld joints properties and health characteristics of the manual arc welding process. Using a new generation inverter power supply allows less heat input into the weld bead, thus, decreasing silicium and manganese burning, improving impact resistance of weld joints under low (negative) temperature and reduces the risk of respiratory diseases for the workers.