The forests in Latvia occupy 49.9% of territory and they have significant economic, ecologic and social functions. The notion ‘forest value’ is frequently understood as the value of wood only but non-wood values are often neglected because there are methodological and practical difficulties to estimate them in monetary terms. The list of forest plant non-wood product (FPNWP) groups potentially important for Latvia was made and the significance of them in Latvia’s national economy was estimated. To obtain the information about FPNWP in Latvia (kinds, amounts, value, own-consumption) the public opinion poll was carried out. 77% of the residents of Latvia aged 18 - 74 have gathered the nature products in Latvia in 2010. The most significant FPNWP are mushrooms, wild berries of family Ericaceae - Vaccinium myrtillus L., Vaccinium vitis-idaea L., Oxycoccus palustris Pers. and birch sap. The contribution of FPNWP in the Latvia’s national economy in 2010 was 66.8 million LVL, including 8.9 million LVL for the products sold in the market or exchanged among households.

According to a respective European Directive, it is now very important to use biofuels in transport as much as possible. Despite that, many studies on the use of biofuels in vehicles are done; the general increase in the share of biofuels in total fuel consumption is mostly achieved by compulsory admixture of biofuel to fossil fuel. In order to perform further studies on the use of biofuels in the existing vehicle fleet in Latvia, it is necessary to define the more widespread vehicle fuel system. In previous studies, the most widespread car fuel systems in Latvia were identified. Overall, 91588 trucks are registered in Latvia as per 01 January 2010, and only 51431 of them are suitable for road traffic. Some trucks of specific brand and model year are more popular and widespread in Latvia than others, and many trucks at the same time have similar or same fuel systems. The objective of this study is to determine the most widespread engine fuel systems for trucks in Latvia. The study is based on the analysis of the Road Traffic Safety Authority data, specific truck model manuals and information provided by car dealers.

ICOEUR (Intelligent Coordination of Emergency Operation and control of European and Russian Power Grid) is a project within which it is planned to develop the European and Russia, Belarus, Ukraine and the Baltic States energy optimal combination approach. Participate in the project 22 partners from 11 countries, including the Institute of Physical Energetic and Riga Technical University of Latvian. The project is implemented by the European Commission and the Ministry of Education (co-financing). One of the project topics is 330kV and 750kV electric ring-S.Pēterburga Moscow-Baltic-Belarus-Smolensk-Moscow modelling and features analysis. Research are made by authors with long-standing operational and technology management experience in static and dynamic stability estimates for the 330kV and 750kV electric ring as well as the development of technology management solutions, introduced the energy specialists, eliminating many situations of emergency. Longer period of time were carried out wiring and electrical parameters of the experimental tests in order to approximate the parameters used in the estimates of their real value. In paper described and analyzed a large power system operational and technological management of underlying problems, which are based on experience and requirements for electricity and electrical parameters. Energy research with dangerous emergency pre-assessment requires a well-ordered and an adequate mathematical model of the system, which would provide both stationary and dynamic electric mode estimates. A major requirement of dynamic electric mode estimates were special programs to check against emergency automation of complex causes efficiency in emergency situations, removing or restricting them to determine the effects the amount of power-generating capacity and changes in consumer load shutdown. Specific program was used iteration method. With a special program step by step was changed emergency automation of complex effects in addition to the quantity or set to automatic emergency centre, providing a stable after emergency treatment.

Environmental pollution with trace elements is considered as one of the most important environmental problems. Analysis of trace element accumulation in sedimentary phases of lakes may reflect the overall regional pollution level, but analysis of trace element accumulation patterns in sediment profiles can help to reconstruct the history of anthropogenic impacts. The aim of this study was to analyse trace element concentrations in the sediments of Lake Engure in Latvia and analyze factors influencing their availability. The metal concentrations in sediments of Lake Engure are at background levels, especially in comparison to metal concentrations in West European countries. However, analysis of element concentration changes in sedimentary profiles gives information about trends of recent accumulation (within the last 300 years) and the balance between natural and human induced accumulation processes. | Vides piesārņojums ar mikroelementiem tiek uzskatīts par vienu no svarīgākajām vides problēmām. Šī pētījuma mērķis bija analizēt mikroelementu koncentrāciju no Engures ezera sedimentiem Latvijā un analizēt faktorus, kas ietekmē to pieejamību. Ezera nogulumu slāņu analīžu rezultāti var sniegt vērtīgu informāciju par ezera attīstības gaitu, kā arī dabiskajiem un antropogēnajiem procesiem un to mainību ezeru sateces baseinā. Pētījuma iet varos tika ievāktas nogulumu serdes, kas laboratorijā tika sadalītas 1 cm biezos slāņos. Šiem paraugiem tika veikts datējums pēc 210Pb, analizēts organisko vielu, karbonātu un metālu saturs. Engures ezeram raksturīgi ļoti heterogēni sedimentu uzkrāšanās apstākļi, ko raksturo atšķirīgs ezera nogulumu slāņu dziļums un to fizikāliķīmiskās īpašības, piemēram, nogulumu analīzes liecina, ka ezera dienvidu un centrālajā daļā pie Dzedrupes ietekas pēdējo 100 gadu laikā ir pieaudzis karbonātu saturs, bet pie Mērsraga kanāla to koncentrācija nav būtiski mainījusies. Metālu koncentrācijas Engures ezera nogulumos vērtējamas kā ļoti zemas, īpaši, salīdzinot ar Rietumeiropas ezeriem. Zemais smago metālu saturs nogulumu augšējos liecina par nelielu antropogēno slodzi, kā arī var norādīt uz dabisku ģeoķīmisko procesu izmaiņām ezera sistēmā pēc Mērsraga kanāla izbūves 1842. gadā.

A method of bioethanol dehydration and a scheme for its realization are offered. The proposed method includes mash distillate rectification and simultaneous water adsorption in the pouring or downwards moving moist adsorbent layer, by feeding the mash distillate vapour flow and the flow of the adsorbent in the rectification and adsorption block, as well as the used adsorbent removing and regenerating of the adsorbent in the adsorbent regeneration unit for reuse in bioethanol dehydration. The active granular adsorbent is used as the adsorbent, which during the feeding in the rectification and adsorbing block is moistened with alcohol solution - intermediate product of the overazeotropic concentration dehydration process, and then the action of moistened adsorbent on dehydrated alcohol vapour injected in the middle of the block is provided, but the water from the used granules is separated by evaporating it in the granule regeneration block. The intermediate product of dehydration process - overazeatropic concentration alcohol solution, necessary for the moistening of adsorbent granules, is removed from the rectification and adsorption block zone, where the alcohol level of intermediate liquid is in range from 97.5 to 98.5 volume percent, by filtering intermediate liquid from the wet adsorbent granules.

40 % of energy in Latvia is foreseen to be produced in 2020 from renewable resources. Fast development of biogas production, as most perspective, started in recent years. The Ministry of Economics of Latvia planned for 2011 quotas for producing 467 000 MWh electricity from biogas with increased tariffs. 58 new biogas plants will be built. The owners are mostly farmers, which have big farms and land. The proposed technologies and equipment suitable for the local conditions of Latvia are analysed. The advantages and disadvantages are presented, conclusions and proposals are elaborated.

One of the perspectives of rural development is the production of biofuels. One of the biofuel production problems is a significant quantity (about 10 %) of a by-product – glycerol occurrence. This problem is offered to solve by adaptation of bacteria Zymomonas mobilis, which is notable for ethanol production facilities. To be able to process glycerin into ethanol using Z.mobilis bacteria, the bacteria must be modified, because its natural form cannot process glycerin. At the same time computer modelling analysis is required, to assess specific modification affectivity in interconnection with other processes in bacteria. The computer model, which describes two genes of - bacteria E.Coli GlpF and GlpK insertions and expressions in bacteria Zymamonas mobilis, describes conversion of glycerol into bioethanol in Z.mobilis bacterial cell. Biochemical reactions and the process regulation network are too complicated, to be able to predict the system response without extensive computer modelling by changing any of its components. The first phase of the model creation was creation of a structure model based on biochemical reactions. The second phase of model creation is stoichiometry analysis. The stoichiometry analyzed the possible steady states and reactions flux. Using the databases KEGG, SABIORK, BRENDA, ChEBI are defined reactants, reactions. Stoichiometry analysis of biochemical network of Zymomonas mobilis adaptation for glycerol conversion into bioethanol was created using program COBRA Toolbox.

Development of higher education in Latvia is influenced by external and internal factors. Therefore, all the EU enactments related to higher education shall be considered in Latvia. It is certain that until now not all legal and regulatory enactments of the Republic of Latvia and other countries, for example, Lithuania and Estonia, confirm to the EU documents. In this paper, the author summarises the general situation in the structure of Latvia's higher education and indicates the tendencies of Latvia's higher education in connection with the European Union. This matter is very pending, since during the previous years all the countries had to accept and confirm the Bologna Declaration documents in order to follow the set aims and to put them in practice. The study concentrates on some main aspects: to evaluate the situation of higher education structure in Latvia and to propose realistic development tendencies while being within the European Union Area.

The article focuses on the research results of differences between the number of dwelling houses and the total area of housing fund in the regions of Latvia. The aim of this paper was to compare and describe development of the housing fund in the regions. The investigation has showed that the development of housing fund was multiform in various regions of Latvia. The reasons for these differences are well-being and the standard of living, the economic development in the regions and other causes. The unemployment that caused migration from one region of Latvia to another with higher well-being has changed the quantity of residents or emigrants. The issues of development of the housing fund in various regions of Latvia still have not been analysed and described widely in scientific literature. The research was carried out employing the method of abstract - logical analysis, the graphical methods, the historical research as well as other well-known methods of economic research.

The current work is dedicated to electrochemical impedance spectra analysis of the fine and coarse airborne particulate matter sampled on the glass fibre filters in Riga city air. The cyclic voltammograms, impedance spectra and double layer capacitance spectra of particulate matter were obtained after the pre-treatment of samples. The equivalent circuit method and the statistical method were used for impedance spectra analysis. Analyzing the impedance spectra, it was concluded that the impedance of both – fine and coarse particles heated in N2 flow does not change by aerosol mass concentration variations. On the other hand, the impedance of particulate matter heated in O2 flow increases, by increasing PM10 mass concentration. Describing the spectra of double layer capacitance, it was observed that the double layer capacitance of aerosols heated in N2 flow did not change, by mass concentration and size variations. However, by increasing mass concentration of coarse aerosols heated in O2 flow, the double layer capacitance reduced. | Pētījumā veikta elektroķīmiskās impedances un dubultslāņa kapacitātes spektru analīze Rīgas pilsētvides gaisa smalkajām un rupjajām aerosolu daļiņām, kas uzkrātas uz stikla šķiedras filtriem. Veicot frakcionēto aerosolu daļiņu ņemšanu vienādu stundu skaitu, smalko daļiņu daudzums bija krietni augstāks par rupjo daļiņu daudzumu gaisā. Pēc aerosolu daļiņu paraugu karsēšanas dažādas vidēs tika uzņemtas cikliskās voltamperogrammas, impedances spektri un dubultslāņa kapacitātes spektri. Kvalitatīvu impedances spektru uzņemšanai izmantoja „sviestmaizes” veida elektroķīmisku šūnu. Pēc uzņemtām voltamperogrammām tika noteikti nepieciešamie parametri aerosolu daļiņu paraugu impedances mērījumiem. Impedances spektru analīzei izmantota ekvivalento shēmu metode un statistiskā metode. Mērījumu precizitāte un ticamība pirms analīzes pārbaudīta ar Krāmera-Kroniga testu. Analizējot impedances spektrus, tika konstatēts, ka gan smalkajām, gan rupjajām, slāpekļa vidē karsētām aerosolu daļiņām impedance nemainās, mainoties daļiņu masas koncentrācijai. Savukārt, gaisā karsētiem paraugiem impedance pieaug, pieaugot rupjo daļiņu masas koncentrācijai. Analizējot dubultslāņa kapacitātes spektrus tika novērots, ka dubultslāņa kapacitāte slāpekļa plūsmā karsētām aerosolu daļiņām nemainās, mainoties daļiņu izmēram un masas koncentrācijai, bet pieaugot skābekļa plūsmā karsēto, rupjo aerosolu daļiņu masas koncentrācijai, dubultslāņa kapacitāte samazinās. Kopumā iegūtie dati liecina par ogles, galvenā aerosolu daļiņu komponenta, virsmas rakstura nemainīgumu, mainoties aerosolu daļiņu izmēram un masas koncentrācijai. Analizējot impedances spektrus augsto frekvenču apgabalā tika noteikta nehomogēna, bez noteikta poru izmēra, trīsstūrveida vai rombveida stikla šķiedru filtra uzbūve.