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The Mechanics of the Shearing Process Studied by FEM-Analysis with Experiments
No full textAxisymmetric shearing experiments have been conducted on aluminium alloys in an equipment mounted in a mechanical press. In addition previous experiments reported in literature performed many years ago are considered. The experiments have been reproduced by building representative FEM-models of shearing. The shearing conditions in the shear zone for different shearing conditions are analysed and it is concluded on how the deformation conditions are in the experiments. The investigation has brought forward new understanding of the deformational behavior in shearing processes
Land for Agriculture and Field Land in Latvia: Market Review
No full textThe Latvian Law on Agriculture and Field Land Development Part 1 reds that Agriculture is a branch of the National Economy that provides for the agricultural production and appertaining services, while Field Land is the rest of the Latvian territory, excluding cities, towns and neighbourhood centres. Agriculture in Latvia is one of the economics` main sectors that provide production of agricultural produce, forms typical country scenery, provides working places for country inhabitants
Synthesis of 2,6-Bis-(1,2,3-Triazolyl)-Substituted Purine Nucleosides
No full textSynthesis and chemical reactivity of novel type of bis-triazolyl purine nucleosides is discusse
Зависимость коэффициента восстановления ударной системы от ее геометрических параметров
No full textБольшое практическое значение имеет задача определения коэффициента восстановления в контактных задачах, когда необходимо избежать повторного переходного процесса во время контакта. Цель данной работы - получить эффект, соответствующий пластичному удару, чтобы в системе не произошел повторный отскок. Для балки используется система с распределенными параметрами
Liquid Metal Target Prototypes for EURISOL Project: Goals And Future Challenges
No full textPoster is dedicated to the concepts of the EURISOL multi megawatt liquid metal target. One of the possible versions could be
windowless target concept. Windowless target concept has the ability to withstand the extremely high loads in the terms of
hydraulic shocks, thermal loads, cavitations, reliable work and adequate lifetime of the target. Meantime this concept hasn’t been
studied much, which give scientific and technological challenge for the scientists and engineers to enforce it. Development of the
windowless target concepts is overseen along with comparison with classical targets. Theoretical considerations and numerical
simulations are viewed. Experimental developments and future concepts of low pressure crossflow targets are shown at the poster
Crystal Chemical Peculiarities of 6-Aminoquinolinium bis(citrsto)borate Dihidrate Structure
No full text6-Aminoquinolinium bis(citrato)borate dihydrate [(6 NH2C9H6NH)(C6H6O7)2B]•2H2O (I) has been synthesized for the first time. The single crystals have been obtained and the full X-ray diffraction analysis of the title compound has been carried out. The structural units of the compound I crystal are large complex bis(citrato)borate anions possessing a spiran structure, 6-aminoquinolinium cations and two molecules of crystallization water. In complex anion two citric acid molecules are bidentately coordinated to the boron atom via the O atoms of central carboxyl and α-hydroxyl groups. The complex anion has pseudosymmetry C2. In 6-aminoquinoline molecule is protonated the nitrogen atom of the heterocyclic ring. The non-hydrogen atoms in 6-aminoquinolinium cation (except the nitrogen atom of the amino group) are coplanar within the limits of 0.039(3) Å. There are eight hydrogen bonds of the O─H…O, N─H…O type in the crystals. Crystal structure obtained for compound I have been compared with the corresponding data for investigated crystalline hydrates bis(citrato)borates of 7-, 8-hydroxy- and 8- and 4-aminoquinolinium cations. X-ray diffraction analysis data allow to elucidate the influence of the mono-substituted quinolinium cations on the complicated crystal structures of bis(citrato)borates crystal hydrates.
C21 H25 N2O16B, triclinic: P-1 (No. 2), a = 9.346(2) Å, b = 11.326(3) Å, c = 12.646(3) Å, = 97.46(2)º, = 106.59(2)º, = 101.66(2)º, V = 1231.1(5) Å, Z = 2, ρcalc = 1.544 g/cm3, ρexp = 1.529 g/cm3, R = 0.0449, Rw = 0.0795, T = 293 K
Ozonation of Activated Sludge in Periodic Reactors
No full textCombining ozonation with aerobic wastewater treatment by using pre- and post-ozonation or other schemes is a known method for improving purification of industrial wastewaters. The application of mentioned methods is usually restricted due to the need of high ozone doses that significantly increases the cost of the purification process. The method of combining of ozonation and aerobic bio-oxidation into single integrated process, described in the current paper, has been found to improve wastewater purification efficiency when small ozone doses are applied. It is demonstrated how small ozone doses improve the performance of the aerobic bio-oxidation process over the conventional aerobic bio-oxidation process. Results revealed that the measurement of mixed liquor suspended solids (MLSS) is not suitable for evaluation of the activated sludge concentration in bioreactor. The measurement of ATP concentration proved to be superior over the MLSS concentration, as its response to ozone attack was immediat
Pragmatic Aspects of Scientific Technical Text Analysis
No full textThe present article focuses on the contemporary tendencies in the
development of scientific technical vocabulary. The rapid scientific and
technological progress results in the development of special language,
which in turn requires the application of new methods of linguistic
analysis and the study of pragmatic aspects of the scientific technical
vocabulary. Analysis of contextual meaning of words they acquire in the
process of meaning shift and extension is of considerable theoretical and
practical importance. The results obtained may be used both as empirical
data for creation and updating of linguistic corpora and as a medium for
further study of meaning transfer and meaning extension in the process of
development of the language in any specific scientific technical domain,
thus contributing to a better understanding of these complex processes
Solar Collectors’ Operation Methods Effect on System Efficiency
No full textA control system has been designed for controlling the circulation pumps of a solar collector system
depending on weather conditions.
To achieve the maximum efficiency of a solar collector system it is necessary to provide the optimum
heat flow rate. Decrease in speed of heat flow leads to increasing heat losses in the pipes, especially
between the solar collector and the accumulation tank. At the same time, increased flow rate reduces
the efficiency of the heat exchanger, so the coolant flow will go at high temperatures thus causing
increased energy losses.
The operation modes of solar collector systems were investigated at the Institute of Physical
Energetics (IPE) solar energy testing polygon for different parameters. The most common types of
solar collector operation modes were studied and compared: based on time, on the difference between
the input and output temperatures of the heat carrier, on the solar radiation intensity, as well as
control techniques in various combinations. The theoretical and practical advantages and
disadvantages of using each control technique were analyzed and recommendations given as to the
efficiency improvement
Research of the Wind Energy Resource Distribution in the Baltic Region
No full textGovernmental support and the availability of large unpopulated areas on the coasts of the Baltic
countries make attractive the use of these lands for siting large wind power plants (WPP).
Studies in the area of wind energy resource distribution are carried out by the IPE with collaboration
with the VeU. The observations of wind speed were made using the measuring complex NRG
LOGGER 9200 Symphonie.
The results of long-term observations on the wind energy density fluctuations at heights of 10 to 60 m
in the area on the Baltic Sea coast of Latvia are presented in the form of tables, bar charts and
graphs.
The wind speed distribution is analysed. The coefficients of approximating functions for two areas of
different terrain types have been calculated, and extrapolation results for the distribution curves of
wind speed and energy density obtained.
The acoustic noise level distribution around a planned WPP has been modelled