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Concept of Smart City: First Experience from City of Riga
No full textGrowing concern of smart city development and urban resilience has become increasingly embedded in urban planning, national security and energy policy. One of the main city documents focused on actions and measures to be implemented in City is Sustainable Energy Action Plan. Taking into account specifics of modern cities and future city development at Smart City level the existing Sustainable Energy Action Plans should be enhanced. Nowadays it is necessary to bring existing standalone energy actions at cross sector level in order to ensure urban resilience. Currently there are 3414 cities across the Europe and eastern partners which already have developed Sustainable Energy Action Plan. The paper draws attention to areas with high impact to smart city development. In terms of Smart Cities the most powerful actions are those which directly affect at least these three sectors - energy, ICT and transport.
Paper provides some Good Practice examples from city of Riga. The losses of the heat transmitted to consumers by JSC "Rigas Siltums" - main heat supplier of Riga have been decreased by 667 thous. MWh or 2.45 times in comparison to year 1996/1997. Following the completion of reconstruction of the boiler houses, construction of a biofuel fired water heating boiler, construction of the biofuel fired cogeneration plant, installation of flue gas condensers for biofuel fired boilers at the DHP the share of biofuel utilisation within the fuel balance of the JSC „RĪGAS SILTUMS” will reach 20.4% in fiscal year 2013/2014. The total energy produced from renewable energy sources since 01.01.1996 until 8.04.2014 is 920463.107 MWh.
The project “Heat meters automatic remote reading system” proved to be a successful and reliable solution for the control and accounting of consumed heat, as well as related tasks enabling “online communication” with 8000 individual heating units throughout the Riga city.
Development and introduction of electric cars and filling station infrastructure in Riga was one more step on the way to the SMART CITY status. Despite a fairly long payback period electric cars are quite beneficial solution for some companies whose activities are related with vehicles’ high mileage within the city as LLC “Rigas Satiksme”
Determination of Parameters to Model Seafarers' Supply in Latvia
No full textShortage of seafarers is important topic as maritime industry plays a key role for economy of the European Union. According to the latest assessment of economic value of shipping industry in 2012, the EU shipping industry is estimated to have directly contributed €56 billion to GDP, employed 590,000 people, and generated tax revenues of €6 billion. During recent years increasing attention is paid to the education and training of seafarers as the seafarers and their knowledge are essential to sustainable development of the maritime cluster, as indicated in the maritime strategy of European Union. Indicative estimates suggest there were almost 38,000 students/cadets in maritime academy – type training across the EU and Norway in 2012, a 11% increase from 2004. Understanding of current trends in the pool of seafarers is prerequisite for successful implementation of the strategy. Main obstacle for assessment of effectiveness is lack of possibilities to monitor contribution from maritime education institutions to current state of European seafarers’ pool. The aim of this article is to show parameters which should be taken into account to model seafarers’ supply in future. The parameters are discussed on the basis of information from the Seamen Registry of Maritime Administration of Latvia
Porous Mullite Ceramics Doped with ZrO2
No full textMullite (3Al2O3.2SiO2) phase is the important stabile crystalline phase in the alumosilicate system. Mullite ceramics with high porosity serve as a heat insulator and filters, as well as can be used in constructional and thermal engineering. Zirconia ceramics also are excellent candidate for high temperature applications, because of high melting point (2715oC), good corrosion resistance and high mechanical properties. The glass phase of Al2O3-SiO2-ZrO2 system begins to form only from 1750 to 1850oC, which is higher than, for example, case of Li2O, Na2O and MgO. Therefore, the ZrO2 is used as modification additive and influences the properties of mullite ceramic
Lignocellulosic Biofuels and Grass Plants Used in Production of Pellets
No full textUse of plant biomass in energy production is one of the preconditions to compensate growing shortage of fossil energy resources. The research covered production of pellet samples and testing of quality parameters thereof. Objective of the study was research of hemicellulose indicators in osier and poplar pellets, lignin content in perennial crops (depending on fertiliser types, norms), parameters characterising pellet mixtures, evaluation and optimisation thereof depending on proportions of pellet components, as well as characterisation of lignocellulose parameters
Apparatus and Selective Solvents for Extraction of Triterpenes from Silver Birch (Betula pendula Roth.) Outer Bark
No full textA method and apparatus for obtaining triterpene extracts and betulin from pelletized birch bark (fraction 0.4-2.0 mm), extracting with petroleum ether (PE140) (boiling temperature range 100-140ºC) at a boiling temperature was developed. In the extraction unit, the process was carried out in a flowing through type reactor in the flow of distilled solvent in the intensive mass exchange regime. The change in the solubility of betulin and other triterpenes of outer birch bark (OBB) in PE140 at varying temperature was used to realise the process. During the process, betulin in the purified crystal form precipitates in the intermediate crystalliser making up 40‒50% of the total amount of extractives, with the total betulin, lupeol concentration of 90‒93 wt.% o.d. crystals. Decreasing the temperature of the solution remaining in the unit’s evaporator, betulin – lupeol crystals with slightly decreased content of betulin, but increased content of lupeol settle. The intensive mass exchange extraction unit can be used also for OBB extraction with polar solvents (alcohols, acetone). The extraction time of pelletized (0.4‒2.0 mm) OBB in polar solvents did not exceed 3‒5 h. However, the action of the intermediate crystalliser was less efficient, therefore required cooling jacket temperature should be lower than 10ºC. The mother liquor, remaining after isolation of triterpenes from the extract, was collected in the evaporator. It contained about 38‒40% of lupeol (wt.% o.d. mother liquor extractives) and can be used for obtaining of pure lupeol
Alternative Financial Timeseries Risk Indicator Estimation by using North-East Volatility Wind Effect
No full textThis paper illustrates alternative indicator for risk estimation. This indicator
is beneficial for financial market instability prediction on early stages. Alternative
risk measure is based on North-East Volatility Wind Effect and its helical (spiral)
structure investigation in frequency domain. Research is based on regularity research of spiral (helical) structure of obtained Fourier coefficients. According research alternative risk measure for financial time series is acquired. This measure could be used for volatility indicator forecasts
Analysis of the Factors Influencing Investments in Intellectual Capital
No full textThe role of intellectual capital investments on company level is increased in last thirty years. According to OECD data tangible assets investments decreased and intangible assets investments increased. Despite of these trends the amount of intellectual capital investments is not significant in Latvia. The aim of the paper is to describe the aspects for the research and survey development in order to prepare sound theoretical basis, as well as to describe and validate solid development of the research. To achieve the aim the previous research and scientific literature are studied and entrepreneurs from certain sectors of national economy are interviewed. In the result of the current research a questionnaire for entrepreneurs was developed and a data base of respondents was created
Influence of the Carbonate-Free Clay Calcination Temperature and Curing Conditions on the Properties of Alkali-Activated Mortar
No full textAlkali-activated materials (AAMs) are one of the most perspective alternatives to the traditional Portland
cement based materials. AAMs could reduce the environmental pollution and greenhouse gas emission due to the lower
heat consumption in production (up to 80% compared to the ordinary Portland cement). In the current research alkaliactivated
mortar was developed from the locally available low-carbonate Illite clay. Experimental work consisted of Illite
clay calcination at different temperatures and regimes (from 500-800°C) and incorporation of the obtained material into
the mixture of alkali-activated mortar. Four curing regimes were applied to alkali-activated mortar. The results indicate
that hardened mortar properties are mainly affected by curing temperature and regime and the compressive strength up to
28.8MPa could be achieved for the mortar samples aged 2 months
Providing Quality of Shredded Carrots during Storage by Treatment with Ozonated Water
No full textThe objective of the current research is to evaluate the quality changes of shredded carrots treated with 2 ppm ozonated tap water for 60 s ± 1 s. Treated carrots have been packed in several materials (hermetically sealed by breathing polymer film BOPP PropafilmTM P2GAF, cellulose based biodegradable NatureFlex NVS and Polilactid BIO-PLA Containers) and stored at the temperature of + 4 C ± 1 C for 10 days. Main quality parameters using standard methods have been analysed: total carotenoids and β-carotene, total phenolic, antioxidant capacity, soluble solids, mass loses, moisture, pH, firmness, colour, CO2 and O2 and microbiological parameters. Testing of the samples has been carried out before packaging and during storage. In the present research it has been proved that is possible to maintain the chemical composition of shredded carrots during storage by treatment of carrots with ozonated tap water; as a result, the shelf-life of shredded carrots can prolong till 10 days
Riverbed Layering Impact on Scour at the Abutments
No full textThe damage of the engineering structures caused by scour leads to considerable economical and envi-ronmental losses. The local flow modification and its changes in time during the floods, as well as local geological conditions, as riverbed layering, type and the shape of the structure are the reasons of the in-creased value of the scour depth. The difference in stratification of the riverbed near structures can be one of the reasons of abutment failure because of the scour formation. Although the problem is very topi-cal, the scour at stratified riverbed conditions at the abutments has not been studied wellThe differential equation of the equilibrium for bed sediment movement in clear-water is used and a method for scour calculation in time at abutments is elaborated. The method is confirmed by test results. When the first layer of the bed model is scoured out, the process is continuing in the next layer, but under new hydraulics parameters. Local velocity at the abutments is decreasing in time, at steady flow, but critical one is increasing or decreasing depending on the grain size diameter in the layer. Scour depth, lo-cal and critical velocities development in time under different open-flow conditions, contraction rate of the flow, thickness and sequence of the layers, as well comparison with tests, are presented in Figures