15,711 research outputs found
Sintering of Titania Ceramics and Bioactivity Assessment
The wide range of application of titania (TiO2) ceramics in many technological fields is related to its characteristics, such as high refractive index, good stability in aggressive environments, high hardness and biocompatibility. Bioactive materials form a bone-like apatite layer on their surfaces in the living body and bond to living bone trough apatite layer. Bioactivity of such a material can be enhanced tailoring surface morphology. The apatite forming ability on bioactive materials can be evaluated in simulated body fluid (SBF).
This work aims at presenting the effects of particle size of raw material on the sintering process and formation of bone-like apatite on sintered ceramic in SBF.
Reducing powder particle size to nanometer level (15 nm) green compact sintering begins at 450 °C. At the same conditions of thermal treatment smaller particle size of anatase powder leads to formation of smaller grain size of obtained TiO2 ceramic. Bioactivity of ceramic is enhanced using nanopowder as raw material
Iedzīvotāju viedoklis par teledarba attīstības iespējām Latvijā
Laika posmā no 2012.gada 27.jūnija līdz 2012.gada 21.oktobrim INTERREG IVC projekta „MICROPOL – attālinātie darba centri ārpus metropoļu reģioniem” ietvaros Rīgas Tehniskās universitātes Tautsaimniecības un reģionālas ekonomikas institūts, sadarbojoties ar Limbažu un Balvu pašvaldībām, īstenoja aptauju, lai noskaidrotu iedzīvotāju viedokli par attālinātā darba izmantošanas iespējām, it īpaši novērtējot šādas darba formas attīstības iespējas Limbažu un Balvu novados
Reindustrializācijas nozīme reģionu attīstībā Latvijā
Rūpniecības atjaunošana un reindustrializācija pēdējos gados ir kļuvusi par aktuālu tēmu gan valdības, gan uzņēmēju, zinātnieku un pētnieku paustajos viedokļos. Lai novērtētu reindustrializācijas nozīmi reģionu attīstībā Latvijā tika izpētīta rūpniecības attīstība un nozīme tautsaimniecībā dažādos Latvijas pastāvēšanas periodos. Rūpniecības uzņēmuma izveidošana reģionā veicina tā konkurētspēju, paaugstina sociāli ekonomiskās attīstības līmeni - rodas jaunas darba vietas, samazinās bezdarba līmenis, palielinās iedzīvotāju ienākumi, kas tiek tērēti par precēm un pakalpojumiem, radot multiplikatora efektu dotajā reģionā
Self-tuning Core-less Serial Resonant DC/DC Converter for Powering Loads on Rotating Shafts
To feed sensors on different turning or rotating shafts of electrical motors, like servo, stepper or DC motor shafts, pan/tilt and different robotic system rotating parts, especially where rotations are up to 3600 and more turns of rotation, conventional wire loop cannot be applied. The same problem also lies with data transmission from sensor. The article describes a way to transfer energy wirelessly from stationary part to rotating (moving) part to solve the problem with power supply and proposed topology allows wireless data transmission, allowing significantly reduce total systems overall complexity and price
Environmental Aspects and Operation Mode of Small Hydropower
The use of renewable sources must be balanced with environmental aspects. Especially it relates to the use of river water flow. Environmental requirements are hard to achieve on large hydropower. Much hydro are built and yet can be built on small rivers, usually building the dams which create small lakes and prevent movement of fauna along the river. In places of large inclination of river channel the dam can be substituted by water ducts, such as pipes. The movement of water in the pipe meets resistance and some part of water pressure is lost. There is little resistance to movement of water by laminar flow of water but this flow exist by small velocities of water. So it can be counted on turbulent flow. By a given diameter of pipe the maximum power can be get when 1/3 of the water pressure is used on water movement in the pipe. The cost of pipe is proportional to pipe length multiplied by the root of fifth degree of the pipe length. Artificial rapids can be made which reduce pipe length. Such a hydro must be connected to a grid. It operates in the rhythm of the river
The Analysis of Fire Risk Assessment Methodology of Petroleum Product Transhipping Terminal
Over time, disasters and consequences have made the
society review the implementation of prevention measures at the
facilities where large-scale emergency situations can potentially
occur. The study examines data on causes and effects of fires and
industrial accidents. Fire risk assessment methodology is based
on the combined use of several techniques: checklist method,
expert method and effect analysis method. The combination of
methods allows carrying out both fire hazard qualitative and
quantitative evaluation
Electric Arc Hazards
This article aims to analyse the electric arc exposure
hazards to human health and to develop proposals for
improvement of safe operation of electric equipment in
organizations. The study is carried out on the situation in the
field of regulatory documents governing the safe operation of
electric equipment; moreover, recommendations are also given.
It is concluded that the standard IEC 61482-1-2 (LVS EN 61482-
1-2) is adapted in the Republic of Latvia, which puts forward the
requirements to protective clothing against electric arc exposure,
but this standard only takes into account the spectrum of
partially served electric devices. It is, therefore, necessary to
introduce the international standard IEC 61482-1-1, which takes
into account the actual short-circuit current magnitude and
environmental layout of electric devices
Risk Reduction Possibilities Considering Equipment, Working Environment and Human Factor in Road Construction
In modern road construction the work becomes even
more intensive, requires maximum attention and concentration;
therefore, practice and experience have been examined in the
organization and implementation of labour protection measures.
The objective is to study to what extent the road construction
workers are influenced by dust containing crystalline silica that
occurs in the process of asphalt concrete milling, based on
Latvian and foreign studies. Additionally, the analysis is
provided and the assessment of risk factors that occur during the
milling process: noise, vibration and ergonomic risks
Tabakas izstrādājumu lietošanas izmaiņas Latvijā saskaņā ar Pasaules Veselības organizācijas Vispārējo konvenciju par tabakas uzraudzību
Tabakas izstrādājumu lietošana ir globāla problēma ar nopietnām sekām sabiedrības veselībai,kas prasa visplašāko starptautisko sadarbību saskaņotai rīcībai, ar mērķi ierobežot tabakas izstrādājumu izplatību un nelikumīgu tirdzniecību. Ir nepieciešama vienota tabakas pieprasījuma samazināšanas stratēģijas ieviešana. Latvijas likumdošanas izmaiņas tabakas kontroles jomā atbilst PVO Konvencijas prasībām, tomēr ir nepieciešams kontroles pasākumu efektivitātes izvērtējums un pilnveidošana
Characterization of Lactose Consumption during the Biogas Production from Acid Whey by FT-IR Spectroscopy
The consumption of lactose in acid cheese whey
anaerobic fermentation process under fed-batch conditions was
studied. During fermentation for 100 hours the biogas production
(CO2 and CH4) was analyzed online. Among the standard analyses
FT-IR spectroscopy was used to follow the consumption of lactose by
bacteria. The absorption bands at 990, 894 and 787cm-1 in the 2nd
derivative spectra were shown to be characteristic for lactose and
were used to follow the lactose conversion. It was shown that acid
cheese whey lactose was converted by bacteria in first 7 hours. In the
spectra of 17, 18 and 95 hour fermentation samples lactos
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