The Stirling engine type alpha is composed of two cylinders (expansion space E and compression space C), regenerator that forms the space between the cylinders and the buffer space (under the pistons). Before the start-up and as a result of long-term operation, the average pressure in the working space (above the pistons) and in the buffer space is the same. However, in the initial phase of operation, the average pressure in the working space is different then the average pressure in the buffer space depending on the crankshaft starting position (starting angle). This, in turn, causes a large variation in the starting torque. An additional unfavorable factor caused by a large variation in the course of the indicated torque is the rotational speed variation and the formation of torsional vibrations in the drive system. After some time, depending on the quality of the engine piston sealing, the average pressure in the working and buffer space will equalize. The occurrence of the above-described phenomenon affects the selection of the starting electric motor, which can be significantly reduced, when the crankshaft starting position is optimized (the starting torque is several times greater than the average torque occurring in the generator operation mode). This paper presents the analysis of the impact of the crankshaft starting position on the course of the indicated torque and the resulting start-up energy. Starting the engine at an unfavorable position of the crankshaft may, in extreme cases, increase the starting torque even three times.

In this paper the current status of microplasma devices and systems made in the LTCC technology is presented. The microplasma characteristics and applications are described.We discuss the properties of the LTCC materials, that are necessary for reliable operation of the sources. This material is well known for its good reliability and durability in harsh conditions. Still, only a few examples of such microplasma sources are described. Some of them have been developed by the authors and successfully used for chemical analysis and synthesis.

Two standardised grades of spheroidal cast iron determined in standard EN PN 1563 – 1997 as: EN-GJS-350 – 22LT (T = –40°C) and EN GJS 400 – 18LT (T = –20°C) are intended for work at low temperatures: –20 and –40oC. The main mechanical property of these cast iron grades is a high impact strength at a work temperature down to: –40°C. A series of controlled melts was performed to optimise the production technology of spheroidal cast iron, which in as-cast state is characterised by ferritic matrix (the best without any pearlite), fine precipitates of nodular graphite and high purity (without non-metallic inclusions). Variable structures of metal charges and various spheroidisation techniques (the modification methods) (slender ladle with a tight cover – Tundish technology as well as the technology with cored wire) were applied in the research. In order to obtain refinement of graphite precipitates and to achieve the ferritic matrix multistage inoculations of technologies were applied. Cast iron was subjected to refining to limit non-metallic inclusions since they decrease the impact strength. The production process of cast iron was controlled by the thermal derivative analysis at the stage of initial cast iron and after its secondary metallurgy (modification and inoculation). It was pointed out, that the reproducible production of cast iron for work at low temperatures was only possible when all elements of the technological process were strictly adhered to. It was pointed out, in the hereby paper, that: it should be strived to maintain Si content not higher than 2.50÷2.60%, which at producing spheroidal cast iron is sometimes difficult and requires using a lot of pig iron in the metal charge. For a fast assessment of the cast iron quality, concerning its impact strength, the proposed – in the hereby paper – index quality (IQu) can be applied. It is determined on the bases of measuring the cast iron hardness and propagation velocity of ultrasound wave.

In this paper a design of millimeter-wave six-port device for LTCC (Low Temperature Cofired Ceramic) technology is presented. Furthermore, problems with implementation of the project taking into account requirements of LTCC technology are discussed.

This paper conducts low temperature welding tests on Q460GJC thick plate (60 mm), and based on the basic theory of phase transformation structure evolution, a three-dimensional microstructure evolution analysis method for large welded joints is established, and the analysis of the evolution process of multi-layer and multi-pass weld structure under the low temperature environment of thick plates is completed. The comparison and analysis of test and numerical simulation results are in good agreement, which proves that the welding phase transformation model realizes the digitalization of metallurgical phase transformation in steel structure welding, and optimizes welding process parameters. It is of great significance to improve the quality of welding products and lay a foundation for predicting the performance of welded joints from the micro level.

Zinc oxide (ZnO) is a prominent n-type semiconductor material used in optoelectronic devices owing to the wide bandgap and transparency. The low-temperature growth of ZnO thin films expands diverse applications, such as growth on glass and organic materials, and it is also cost effective. However, the optical and electrical properties of ZnO films grown at low temperatures may be inferior owing to their low crystallinity and impurities. In this study, ZnO thin films were prepared by atomic layer deposition on SiO2 and glass substrates in the temperature range of 46-141℃. All films had a hexagonal würtzite structure. The carrier concentration and electrical conductivity were also investigated. The low-temperature grown films showed similar carrier concentration (a few 1019 cm−3 at 141°C), but possessed lower electrical conductivity compared to high-temperature (>200°C) grown films. The optical transmittance of 20 nm thin ZnO film reached approximately 90% under visible light irradiation. Additionally, bandgap energies in the range of 3.23-3.28 eV were determined from the Tauc plot. Overall, the optical properties were comparable to those of ZnO films grown at high temperature.

Proteases play a key role in cell defense mechanisms to cold-induced oxidative stress. Data on the relationship between cold stress, growth phase, and temperature preferences of the fungal strains isolated from different habitats are very scarce. Here, we report changes in the intra- and extracellular protease activity of three fungal Penicillium strains (two Antarctic and one temperate) under transient temperature downshift during exponential- and stationary growth phases. The results indicated enhanced enzyme levels in both growth phases depending on the degree of stress and strain thermal class. In order to explain the obtained data, we compared them with our previous results on the protein carbonyl content, accumulation of oxidative-stress biomarkers, and antioxidant enzyme defense in the same three fungal strains. The cell response was affected by the temperature preference of the strain, but not by the climatic distance between the locations of isolation.

In the present study, the mechanical properties and high-temperature sliding wear behaviour of the Al6082-SiC-TiO2 hybrid composite in different environmental conditions produced by the stir-casting process were investigated and distinguished with single-reinforced composites (Al6082-SiC and Al6082-TiO2) and matrix alloy. The microstructure of composites exhibited a reasonably uniform scatter of particles in the aluminium matrix with good bonding between the matrix-particle interfaces. The hybrid composite’s hardness and ultimate tensile strength showed higher hardness and tensile strength than matrix alloy and single-reinforced composites, whereas trends were reversed for the elongation. The impact test of the materials was conducted at different temperatures (room temperature, 0°C, –25°C, –50°C, and –75°C). The hybrid composite shows higher impact strength than the other materials, and impact strength decreases with temperature because ductility decreases with temperature. The fracture surfaces were examined to identify the fracture mechanism. The sliding wear test was conducted at different temperatures (room temperature, 100°C, 175°C, 250°C and 325°C) to distinguish the tribological behaviour of materials. The weight loss of the materials was increased with an increase in temperatures. The hybrid composite shows a lower weight loss than the other condition samples, irrespective of the temperatures. The wear surfaces were examined to predict the material removal mechanism.