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Development of Poly(Vinyl Alcohol) Cryo-Systems with Medicines and Their Comparative Study of Antimicrobial Activity and Cytotoxicity
No full textThe aim of the work was to develop the poly(vinyl alcohol) cryogel systems (PVAGS) with plant extracts (PPe) and simple conventional medicine (Cm), and compare their antimicrobial activity, biocompatibility and cytotoxicity. The stability of gels systems with and without medicines was determined, the gel content and swelling degree were calculated. In vitro studies of PVAGS, with and without medicines, microbial contamination risk – the colonization level of the microorganisms and adhesion activity for the use of gel materials for the wound care were detected. PVAGS biocompatibility and cytotoxic properties were examined on cell lines
Capacitor Activated Self-Excitation System of Synchronous Generator
No full textIn this paper the self-excitation system of synchronous generator based on capacitor discharge through excitation winding is described. The system comprises three-phase synchronous generator with connected in star scheme stator winding with neutral wire and independent excitation winding. When revolution speed of synchronous generator is at proper level then signal is passed to electronic charging generator and capacitor is gradually charged up to necessary voltage. When voltage level is proper high electronic generator is stopped and signal is passed to thyristor control unit which generates firing pulses to all thyristors simultaneously and capacitor is discharged in oscillating way through excitation winding arising proper excitation current which provides self-excitation of synchronous generator. In the paper operation of system, calculation of processes and results of experimental investigation is described
Perspectives of Rural Development in Latvia
No full textThe proportion of rural population is decreasing not only in
Latvia, but all over the Europe. It is forecasted that along with
a further increase in agriculture’s productivity the number of
jobs in Latvian rural areas will continue to shrink. Therefore
questions arise on the future of rural population. We are going
to outline the perspectives of the rural development based on
theoretical considerations, Scandinavian experience and an
example of a rural municipality – Durbes novads – in Latvia
Governance and Socioeconomic Performance
No full textThere are wide discussions on the causes of the differences in the economic performance. Recent studies have stressed out the crucial role of institutions – formal and informal constraints that shape human interaction. The aim of this article is to evaluate the influence of governance – traditions and institutions by which authority in a country is exercised –on the socioeconomic development. To measure the level of governance we used World Bank’s Worldwide Governance Indicators and such indicators as GDP per capita, unemployment, life expectancy at birth, public expenditure, school enrolment (tertiary) and GINI index. The analysis was done by calculating correlation and regression coefficients. It covers up to 202 countries on the world scale and 34 countries on the European scale. The results of the analysis approve that governance plays an important role in state’s socioeconomic performance. Investments in the governance and especially government effectiveness will bring socioeconomic benefits to the state and its inhabitants
Elastomer/Nanographite Composites for Mechanical and Chemical Sensing
No full textblack composites we can achieve excellent piezoresistivity effect [1] as well as
chemoresistivity effect [2] for these composites. In this study we attempt to design
polyisoprene matrix composites with promising more sophisticated fillers – thermoexfoliated
graphite (TEG) as well as multiwall carbon nanotubes with high (LMWCNT) and low
(SMWCNT) aspect ratio for their application in design of new sensitive polymer composites.
TEG has been synthesized in Department of Physics of Kyiv National Taras Shevchenko
University. Powders of LMWCNT and SMWCNT have been bought from Cheap Tubes Inc.
Polyisoprene/TEG and polyisoprene /MWCNT composites were prepared in Institute of
Technical Physics of Riga Technical University. Firstly each filler party was dispersed in
chloroform in one vessel by ultrasonic homogenizer. Secondly polyisoprene and necessary
additives, zinc oxide and sulphur were dissolved in chloroform in another vessel by magnetic
stirring. After the definite filler dispersion was added to polyisoprene solution and the mixture
was mixed by magnetic stirring for 24 hours. From the obtained raw mixture chloroform was
evaporated. Finally the mixture was vulcanized under pressure of 30 atm at 150oC for 15
minutes. The acquired nanocomposite samples were electrically conductive and showed the
ability to change the electrical resistance under the influence of mechanical force and volatile
compound vapours as well
Interaction of Main Stakeholders in an Innovation Process
No full textAn economy is a system for coordinating the productive activities of many people. In a market economy that coordination usually takes place without any coordinator: each individual makes his or her own choices. Yet those choices are by no means independent of each other: each individual’s opportunities, and hence choices. Therefore it is useful to analyze the individual choices, behaviour, possible strategies and outcomes of individuals who interact each other in the innovation system. Situations and actions of stakeholders in the definite circumstances can be conflict or cooperative, depending on their interests. Therefore it is necessary to analyze the current situation of stakeholders and their interaction in the innovation process using game theory
Synthesis and Studies of New Cationic Amphiphilic 1,4-Dihydropyridine Derivatives Containing Styrylpyridinium Moieties
No full textSynthesis of new cationic amphiphilic 1,4-DHP derivatives containing styrylpyridinium moieties, studies of self-assembling, fluorescent and antioxidant properties
Feasibility of Reinforcing Birch Plywood with Hemp Fibres
No full textThe present paper reflects searches for solving the problems of enhancing the strength of plywood, reinforced with hemp fibres. A radical possibility of obtaining a new environmentally friendly material with enhanced strength characteristics is shown. The modern developing society has faced the problem of ever increasing demands for the energy intensity of production and the limited potentialities of meeting them. Recently, the worldwide demand for the sources of natural renewable resources has grown, governed by the energy saving and environmentally friendly technologies of their production, and the feasibility of their processing to environmentally friendly, biodegradable materials with a high added value due to the decrease of material and energy costs. One of such resources is hemp, which is rather profitable, requires much less amounts of artificial fertilisers than other cultures, has a favourable effect on the agroecosystem, improves the soil structure, and inhibits weeds, pests and diseases. Hemp fibre is one of the strongest natural fibres and its characteristics (high tensile strength, wet state strength, etc.) make it technically feasible for the production of different industrial products.
It is shown that the reinforcement of birch five-layer plywood by hemp textiles with a cell size of 8 mm makes it possible to produce an environmentally friendly composite material. Optimal ratios of the components and the binder for producing a composite material of birch plywood, reinforced by hemp textiles, with enhanced mechanical characteristics in bending σbend up to 13.2 % and modulus of elasticity up to 10.3 % have been found. The given composite material can be used for the production of curved-glued furniture and other goods from plywood
Necessary Amount of Spray Water for Optimal Flue Gas Condenser Operation
No full textA calculation model was developed to determine optimal flue gas condenser operation modes in evaporation and condensation zones. One of optimization parameters that could be changed is amount of water to be spayed into flue gases. Optimal amount of spraying water was determined in various boiler operation modes
AAS "BTA" apdrošināšanas pakalpojumi nekustamā īpašuma jomā
No full textMājoklim cilvēka dzīvē ir liela nozīme - tā ir vieta, kur cilvēks jūtas labi un droši, tā ir viņa patvēruma vieta no ikdienas rūpēm, kur pēc garās darbadienas atgūt spēkus. Lai māja tiktu labi uzturēta un labi sakopta, tiek pieaicināti profesionāli mājas apsaimniekotāji vai apsaimniekošanas firmas.
Pētījuma mērķis ir izpētīt un apkopot AAS "BTA" piedāvāto nekustamo īpašumu apdrošināšanas pakalpojumu klāstu un pilnveidot to tālāku attīstību