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Surface Texture Parameters Application for Nanocoatings
No full textSurface roughness is a quality indicator of the surface. Due to the introduction of the new standard ISO 25178-2:2012 nanocoating surface has begun to be explored in volume rather than through the profiles, as it was done previously. In this work surface 3D topography parameters of different coatings on the basis of TiAl were analysed in order to determine the highest quality coatings.
Age-Related Analysis of Structural, Biochemical and Mechanical Properties of the Porcine Mitral Heart Valve Leaflets
No full textThe aim of this study was to assess structural and biochemical differences in the
extracellular matrix of the fetal and adult porcine mitral heart valves in relation to
their mechanical characteristics. Using tensile tests it was demonstrated that the
material properties of porcine mitral heart valves progressively change with age. The
collagen content of the adult heart valve, as estimated by hydroxyproline assay,
increases three times as compared with fetal heart valves. Transmission electron
microscopy demonstrated that the diameter of collagen fibrils increased in adult heart
valves compared with fetal heart valves. The level of collagen cross-linking is lower
in the fetal heart valve than the adult heart valve. The reported age differences in the
material properties of fetal and adult porcine heart valves were associated with
increases in collagen content, the diameter of collagen fibrils and the level of collagen
cross-linking. These data lay a foundation for systematic elucidation of the structural
determinants of material properties of heart valves during embryonic and postnatal
valvulogenesis. They are also essential to define the desirable level of tissue
maturation in heart valve tissue engineering
Experimental Research of Assembly Features of Cylindrical Parts Set by Interference Fit
No full textTo design assembly automates for pressed parts the capacity of power needed for pressing-in shall be defined. Reserve of pressing power is necessary to provide the assembly of details with interference fit by pressing. The current method for calculation of the pressed part interference fit is not accurate enough considering that cylindrical details are a dimensional object; therefore, roughness parameters corresponding to real surface shall be defined. The demand for a more precise calculation method is facilitated by development and progress of mechanical engineering, which asks for more and more accurate equipment and resistant parts with high durability.
Multiple Frequencies Precise GNSS RTK System Research in Dynamic Mode
No full textHigh precision GNSS systems are widely used for geodetic measurement. Given research work presents the possibilities to use GNSS system with phase measurements and real time data correction to establish location of dynamic objects. Test was done by using specially equipped vehicle, which was equipped with high-precision two systems (GPS and GLONASS) phase meter Topcon GRS-1 and a real-time correction system, which used GSM GPRS data transfer forma
Metaphor in Terminology: Visualization as a Key to Term Perception
No full textMetaphor has recently gained extensive interest most probably due to developments in cognitive sciences and the study of language as the reflection of humans’ world perception. Metaphor is no longer reckoned as solely literary expressive means. Nowadays it is studied in a whole number of discourses, such as politics, law, medicine, sports, etc. with the purpose of the analysis and determining its role. The scientific language is not an exception. It might seem that metaphor cannot suit it; we would dare to draw a hypothesis that metaphor has indeed found its stable place in terminology.
In comprehension of metaphorically represented terms the stage of visualization plays a significant role. We proceeded on the assumption that this stage is the main in provision of better term comprehension and would try to exemplify it with metaphorically-oriented terms
An Insight into Contemporary Theory of Metaphor
No full textThe perception of metaphor has changed a lot since the end of the 20th century. Metaphor is no
longer considered to be a purely literary trope, the boundaries of its usage have shifted greatly. Metaphor nowadays is an expressive means studied in numerous f
ields, it is present in political,
economical, scientific, art and other discourses.George Lakoff and Mark Johnson were the pioneers
in ascribing completely new characteristics to metaphor and changing overall perception of
metaphor as being a solely liter
ary expressive agent. The report dwells upon the contemporary
studies of metaphor, its interpretation and reconsideration in modern linguistics. The approaches
to metaphor analysis and study proposed by various linguists are overviewed, too
The Source Domains Employed for Metaphorization of Transport Terms
No full textThe present research dwells upon the metaphorical representation of transport (car and railway) terms. The analysis is carried out on the basis of the study of certain English-Russian terminological dictionaries in the field of car and railway engineering. The research is aimed at identifying the most common source domains employed for metaphorical representation of the terms in the selected fields with the juxtaposition of the English and Russian counterparts. The most common source domains have been identified in the English language and the English and Russian counterparts have been compared in order to analyze the coincidence or difference in metaphorical representation
Functional Properties of Glass–Ceramic Composites Containing Industrial Inorganic Waste and Evaluation of Their Biological Compatibility
No full textA study has been carried out on the feasibility of using Latvian industrial waste (peat cool ash, fly ash, aluminium scrap metal processing waste, metallurgical slag and waste cullet glass) and raw mineral materials (limeless clay) to produce dense, frost resistant, chemically durable glass–ceramic materials by powder technology. Highly crystalline and dense products (density: 2.50–2.94 g/cm3, water uptake: 1.3–4.3%) were fabricated from different mixtures by sintering at temperatures in the range of 1060–1160 °C. Glass–ceramics were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and four point bending strength test. Chemical durability, soluble salt crystallization as well as biological tests were carried out in order to evaluate the environmental stability and possible toxicity of the materials. The novel glass–ceramics developed here can find applications as building materials, such as wall tiles and for manufacturing industrial floors
Reduction of Power Losses in Measurement Subsystem for Tapped-Inductor Based LED Driver
No full textThe shortage of energy resources as well as the increasing price of electrical power leads to new studies in the field of efficiency improvement for all kinds of electric devices. Lighting systems are not exception. Smart lighting systems are capable to reduce electrical power consumption significantly by the regulation of the illumination level in accordance with proper light regulation strategy. The main element of such a system is a lighting fixture with dimming possibilities. As the allast of lighting fixture affects the overall efficacy of the device, it is important to evaluate ballast at all
operation points (in the whole regulation range). Also the approach of the illumination level control
should be taken into account.
This paper considers tapped-inductor based driver (which is the key part of the ballast) for a dimmable LED luminaire. Brief description of tapped-inductor converters is given at the beginning of this article. The description of considered parameters is given in the following section. Next section of this paper presents search for the best configuration and topology among the family of tapped-inductor converters. Then the numerical calculations of the considered parameters as well as the results of experiments are summarized. Considerations on the construction of closed loop regulation also are given. Finally, the conclusions about the expediency of the use of tapped-inductor based LED drivers are given