The paper presents the coupled electro-mechanical problem. In the numerical analysis of the issue, piezoelectric solid-to-shell transition elements were applied. They combine three-dimensional or hierarchical shell piezoelectric elements with piezoelectric first order elements. The mentioned first order of the element refers to the field of transversal displacements of an element. The mechanical field of the discussed piezoelectric elements may correspond to: the model of three-dimensional theory of elasticity, hierarchical shell models of higher orders or the first order shell model. The electrical field of the potential may be modelled with hierarchical dielectric first order models or higher in transverse direction or with a three-dimensional theory. Effectiveness of modification of algorithms of classical piezoelectric elements was assessed in this paper. To perform such an assessment, curves of convergence of hp method in model tasks are presented. Curves obtained with the use of classical and modified piezoelectric transition elements were set and compared.
In this paper, an outlook about the present of electrical aviation is given. The relatively small energy density of current battery technologies is adequate to build usable electric car, but not suitable for electric aircraft. Because of the very limited amount of energy available on-board, a couple of percent in efficiency can give significant increase in range and flight time, hence the development of more efficient propulsion system and E-motor is as important as the development of battery technologies. Current research results at the University of Dunaujvaros show, that building E-motors from amorphous materials is possible, and can easily increase the efficiency of high speed E-motors.
A short survey is reported on the advantageous and disadvantageous properties of soft magnetic glassy tapes to build stator and rotor elements for the increase of motor efficiency. The relative high saturation magnetization and the relative permeability of these alloy groups seem to be promising in this application field. On the other hand, the sample thickness (30 µm) displays limitations in terms of a filling factor. High hardness of tapes hinders the effectivity of mechanical shaping. Laser cutting can be successful as shaping method, presuming that the extension (thickness) of heat affected zone (HAZ) can be successfully reduced below 50µm, avoiding the brittleness evolution.
Assessment of the colour with the use of many parameters is used with reference to evaluation of the quality changes of products resulting from application of specific technological treatments. The paper investigates the effect of relations between parameters of irradiation of potato bulbs with UVC on selected coefficients of assessment of the colour of fries determined with CIE L*a*b* method. It was statistically significantly proved that UV-C radiation affected brightness of fries, change in colour, recognition of the difference in colour and intensity of the colour reception. Statistical analysis of results was carried out at the assumed level of significance α=0.05.
This paper presents research on the impact of printing speed on the strength of a manufactured object and is the next stage of the author's research on the impact of technological parameters of 3D printing on the strength of printed models. The tested universal specimens were printed using the FDM (Fused Deposition Modeling) method from PLA (polylactic acid, polylactide). The paper presents the maximum breaking force of the samples and the time of printing samples depending on the printing speed, which varied from 20 mm·s−1 to 100 mm·s−1. The research indicates that the strength of samples decreases with increasing speed. In the range of 50-80 mm·s−1, the strength of the specimens remined at a similar level, however, above 80 mm·s−1, it decreased significantly.
Eva Nedeliaková, Vladimíra Štefancová and Michal Petr Hranický
The provision of quality transport services is a prerequisite for the creation of an efficient organization that can meet the expectations and requirements of both the enterprise itself and its customers. From the railway enterprise's point of view, it is necessary to pay attention to the increasingly demanding requirements of its customers in railway passenger transport. This article focuses on identifying defects in rail transport processes that negatively affect ordinary operations. One of the most serious bottlenecks affecting railway transport reliability is the train delay, which fundamentally affects the perception of railway transport. At the same time, it emphasizes the need to apply individual tools according to the DMAIC cycle in order to achieve continuous improvement. The aim of the implemented Six Sigma methodology in railway enterprise is disciplined application of statistical problem-solving tools to recognize the gaps in the transport process and set out individual steps for their gradual removal.
Development investment capacity of farms depends on their potential and scale of production, and thus its revenue, which determines the scale of investment purchases. Most specialized farms have growth potential. Farmers take great interest in modernization and investing in new technologies, machinery and agricultural land, as confirmed by market analysis. Literature references offer information regarding the needs and investment opportunities of territorially diversified farms running conventional production, however the aim of the work is to determine the investment possibilities of organic farms with various production branches. The research included 50 farms certified as ecological producers. In order to answer the question which type of business has the greatest development potential, the examined facilities were divided into branch groups.
The objective of the paper was to determine the costs of production and production effectiveness of pellets made of sawdust and characteristics of logistics of raw material carriage and distribution of pellets. The scope of the paper covered the research carried out in the branch of DREWEX company located in Chotelek town (Świętokrzyskie voivodeship, Province of Busko Zdrój). Unit costs of pellets production were: 513.4 PLN∙t−1 for option 1, 423.3 PLN∙t−1 for option 2 and 393.3 PLN∙t−1 for option 3. The most favourable was option 3 when the pellets were produced on the technology line in the 3-shift system day and night. The average distance to seven cities from which sawdust was delivered was 43.6 km and the distance to which production was distributed to ten cities was on average 105.5 km.
The article is devoted to solving the fundamental and applied problem of nonlinear structural mechanics of machines by introducing into the drum two additional stop cylinders with supporting rollers at the end and adjustable length, providing a given elliptical or circular shape of a flexible shell with a smoothly variable geometry in the area of its contact with compacted pavement material. Compaction of soil, gravel and asphalt concrete in the sphere of road is not only an integral part of the technological process of the roadbed, road foundation and surface construction, but it is actually the main operation to ensure their strength, stability and durability. The quality, cost and speed of road construction, the possibility of using fundamentally new technologies, structures and materials is largely determined by the availability of modern road machinery.
The article presents an algorithm for calculating selected energy assessment indexes for grain driers. Particular attention was paid to the conversion of the equations obtained for the operating conditions of the drying process into equations allowing the calculation of indexes for the standard drying conditions. The indexes obtained allow a proper comparison of dryers operating in varied atmospheric conditions, as well as humidity and temperature of the dried material.