bluuebunny/crossref_metadata_2025 huggingface dataset:
Physico-technical approach to design of composites from mineral and polymer technogenic resources
Authors: Noviks Gotfrīds
Published: June 2015

Artificial composite materials are currently being produced in large quantities, they are diverse and they are widely used in the economy. There have been extensive theoretical and experimental studies of different types of components, developed the calculation methods of composites production with predefined properties.

At the same time industry produces a lot of mineral and polymer waste, which are practically technogenic resources, but their use is currently at quite low levels. The paper examines the possibilities to use technogenic resources- mineral (such as ash and clay) and organic (polymers -PET containers) for producing qualitative composite materials. For this purpose theoretical analysis and calculations of the physical properties of components and process parameters that determine the operating characteristics of the composite material were carried out.

Composite-forming process efficiency determinative parameters were analysed: adhesion, the specific surface energy, specific free surface, adsorption capacity and the degree of dispersion of the particles.

The role of external factors in processing of composite were examined – temperature, concentration of components.

The characteristics of prepared samples of composites showed the possibility to use these waste for the development of qualitative products for different purposes.
Adaptive control of the indentation made by the drilling tool
Authors: Lengerov Angel
Published: June 2015

The objective of this study is to determine the advisability of introducing adaptive control of the indentation made by the drilling tool depending on the structural characteristics of the processed part.  In the cases when the adaptive control is economically advisable, the selection of the technological cycle and the speed of moving of the tool can be achieved by the implementation of the respective algorithm for optimization of the dimensions fed for drilling. 
Harmonization of piece-by-piece measurement methods in all stages of roundwood manufacturing processes
Authors: Miklašēvičs Ziedonis
Published: June 2015

In the sawmill industry in Latvia the roundwood represents about 70 % of the total production cost. The quantity measurements of the round wood are required throughout the logic chain of wood from forest to the sawmills but inspite of a large proportion of the total cost the term “true volume” of roundwood is equally actual for supplies and processors of wood.  The roundwood volume results differ measured the same load by measuring the diameters of log in short intervals using harvester measurement systems and in sawmills by measuring the diameters of log in short intervals using electronic 3D systems or measured manually using the most accurate method according to the requirements of standard LVS 82:2003 by measuring top and butt diameter.  This means that it is a great interest in industry to develop the measurement methods and systems to have a lower cost and more efficient algorithm to determine the wood volume.

The purpose of this study is to compare the wood volume calculation results made by the most accurate manual and automatic measurement methods and give the recommendations for minimizing difference between them.

The research is a continuation to the work done in the project „Harmonisation of piece-by-piece measurement methods of roundwood approved by Standard LVS 82:2003 „Apaļo kokmateriālu uzmērīšana” (Miklasevics, Z., 2013).
Soil erosion risk assessment at small catchments scale: comparison of GIS-based modelling and field survey data and its implication for environmental maintenance of rivers
Authors: Soms Juris
Published: June 2015

One of the limitations to implementation of effective measures to mitigate negative environmental and economic effects associated with soil erosion is the lack of data on the geographic distribution of erosion risk and potential erosion hotspots. Hence, experts and policy makers in many cases have no spatially referenced information on which to base their decisions. There is a trend approved by EU institutions and agencies to use soil erosion models which can be integrated into geographic information systems (GIS) environment in order to obtain data at different spatial scales and to assist such decision-making. Despite that, until now in Latvia only some studies on the GIS-based modelling of potential soil losses have been conducted. Considering that, in the study presented in this paper soil erosion risk assessment has been performed by the widely used Revised Universal Soil Loss Equation (RUSLE) model over five selected small catchments of the river Daugava valley. In order to validate the results of modelling and to assess if theory accords with a real situation, the theoretical data were compared with information gained from the field survey of the same catchments. Modelled potential soil loss from each of five catchments under study totals 0.25; 0.26; 0.42; 0.51 and 0.58 t ha-1 y-1 in average. However, results of the comparison indicate the discrepancies between modelled and measured values, i.e. the used empirical model underestimates the soil erosion risk. The recognition of this fact raises implication for appropriate environmental maintenance of rivers, due to possible underestimation of eroded material delivery to receiving streams and, subsequently, under-prediction of water pollution.
Variability of estimated contamination extent depending on calculation methods
Authors: Zinkutė Rimantė , Taraškevičius Ričardas , Gulbinskas Saulius , Stankevičius Žilvinas , Jankauskaitė Margarita
Published: June 2015

The aim of research was to analyse the changes of contamination extent (E, %) estimated using two methods of background calculation by eliminating anomalies outside the interval mean±2s or median±2MAD (s is standard deviation, MAD is median absolute deviation) and optional normalisation. Two methods were used for estimation of background values (B) and upper threshold values (T) of Ag, As, Ba, Co, Cr, Cu, Mn, Mo, Ni, Pb, Sn, U, V, Zn and selected major elements according to their contents in topsoil samples from football fields in less contaminated districts of Klaipėda. Then two different sets of B and T values were applied to the whole geochemical data set. After determination of two sets of concentration coefficients (Kk), four sets of enrichment factors were calculated: two simple (EF1) (normalisation by Al) and two complex (EF3) (normalisation by Al, K, Ti).  

Estimation of E using T values resulted in lower percentage compared to percentage of sites where Kk>1, EF1>1 or EF3>1, because the latter 3 indices depend on B values. Since all T values obtained by median±2MAD method are much lower (by 6-37.1%) than by mean±2s method, respective E is much higher: for 11 pollutants it is higher by more than 5% (range 6.3-34.2%). Since the absolute difference between B values estimated by two methods is much lower (only for Sn and Mn exceeds 5%) than the difference between T values, the influence of different B values on estimated E is much lower. Higher than 5% absolute difference between two sets of E estimated according to Kk>1 is observed for 5 pollutants, according to EF3>1 for 4 and according to EF1>1 only for 3 pollutants. So E estimated according to EF1>1 is least of all influenced by the method of determination of B values, besides, it usually gives the highest E.
Creep gantry quay and accounting environment in its reconstruction
Authors: Korovkin Vladimir
Published: June 2015

Quay gantry type calculates in the technical literature in the form of a frame with  hard rigel  and rigid stopping up of piles. To account for long-term durability of the structures in the plastic clay soils in the existing scheme is additionally used the equation of state of a Newtonian viscous fluid. In Its uses the coefficient of shear viscosity.

The author used the proposed of the early engineering universal method of calculating berthing quays with respect to the thin walls,    secured of anchor piles. In the design scheme not used lower  secured racks, and counts up the stiffness characteristics of the soil, clarifying the nature of the work structures.

To account for the operation of facilities in the plastic clay soils in the proposed scheme uses a different equation of state of a Newtonian viscous fluid. It uses the ratio of the coefficient of viscosity in compression of porous soil (coefficient of Trutona).This allows us to consider how long-term strength and displacement of the structure in time.

Considers the issues of contamination and turbidity in the reconstruction of the gantry bulwark.
Numerical simulation of urban berthing quays in a dense housing
Authors: Korovkin Vladimir
Published: June 2015

Calculation of pile quay gantry type as a frame with rigid crossbarand a rigid beam, is a special case of the decision method, presented by N. Gersevanov. This method was widely used in the technical literature and regulatory documents. Translation of manual calculation on the computer almost retained the existing design scheme.

Practical implementation of the engineering universal method offered early to calculation of mooring embankments in relation to a thin wall, is given by anchored inclined piles. In the calculation scheme bottom sealing is not used, and entered stiffness characteristics of the soil, clarifying the nature of the work structure.

The obtained simplified solution determines the lateral pressure in the silo variable width. Engineering calculations showed that pressure is redistributed on the sheet pilling wall and  the inclined piles  from external soil pressure.

Comparative calculations, taking into account the deformation characteristics of the soil showed a significant impact on efforts in the elements of the embankment compared to method N. Gersevanov.
Climate dynamics of the Beloe Sea catchment area
Authors: Nazarova Larisa
Published: June 2015

The climate of the Beloe Sea  catchment area (total size 717.7 km2, 714 of which belongs to Russia) is described. The territory is characterized by several geographic zones, thus substantial diversity of climatic conditions is observed. Climate variability in the region was studied using data from the longest available instrumental observations at weather stations (WS) and gauge sites of the Russian Federal Hydrometeorology and Environmental Monitoring Agency located in the study area, covering the period from the beginning of observations at the stations until 2012-2013. The data obtained were statistically processed with due regard to the research tasks. Modern observational data are analyzed to distinguish the changes in the climatic regime of the main parameters, i.e. air temperature, precipitation, sunshine length, etc. Since 1989, the stable increase of mean annual air temperature (1-2оC) over a climatic norm is observed. The most intensive warming is typical for the winter months. The analysis of changes in precipitation over the study area demonstrates the stable increase of annual sums, deviation of which from the climatic norm in the first decade of XXI century is about 50-100 mm
Assessing the potential of coniferous greenery from logging residues in Latvia using a system dynamics model
Authors: Muizniece Indra , Dace Elina , Blumberga Dagnija
Published: June 2015

Latvia is the fourth most forested country in Europe. 52 % of the country’s area is covered by forest lands. Approximately 41 % of the forests are composed of conifers that are the most harvested among the tree species in Latvia. Therefore, as a result of logging, large amount of coniferous residues are created and abandoned in forests.  There are several alternatives for sustainable use of coniferous residues. Still, the exact quantity of the resource is not known. Thus, it is not clear, whether its amount is sufficient for products’ manufacturing. The aim of the study is to assess the potential of the coniferous greenery from logging residues’ extraction in Latvia. A system dynamic’s model that allows simulation of complex forestry processes depending on various endogenous and exogenous factors has been built for this purpose. 
Research of dumps at construction sites in the urban area
Authors: Galitskova Yu.
Published: June 2015

The article deals with the problems of the construction waste formed in the course of demolition and construction of buildings in the city. The author presents results of investigations of construction sites located on the territory of Samara, gives the analysis of the construction waste composition and considers options for the use of the construction waste as a secondary resource in the manufacture of building materials.
The toxicity of Lake Onego sediments in connection with the natural and anthropogenic factors influence
Authors: Kalinkina N.M. , Sidorova A.I. , Galibina N.A. , Nikerova K.M.
Published: June 2015

The toxicity of the sediments detected in the northern bays of Lake Onego is determined by anthropogenic factors (pulp-and-paper industry and communal waste waters). Besides the toxic bottom sediments were observed in the central deep part of Lake Onego, which is connected to the geotectonic features of the area.
Amount of Air Ions Depending on Indoor Plant Activity
Authors: Siņicina Natālija , Skromulis Andris , Martinovs Andris
Published: June 2015

Literature sources and earlier researches state that plants may be able to produce a variety of air ions, including negative light ions. In this article, the regularity of influence of plants on the number of ions in the room is being proved, basing on a series of experiments performed with the following plants: Spathiphyllum, Scindapsus, Strobilanthes, Chlorophytum and Pinus mugo. It was concluded that plants, in general, are able to stabilize the indoor ion concentration and reduce its fluctuations. The plants help to increase the concentrations of negative ions and decrease the concentration of positive ones, however the optimal and “healthy” ion concentration was not reached. Plants without artificial illumination work more as ion reducers, not producers.
Anthropogenic Impact on the Macrophytes of Pskov Region Alkalitrophic Lakes
Authors: Sudnitsyna D.N.
Published: June 2015

In 2007 a research of the macrophytes species composition in three alkalitrophic lakes of Pskov region was conducted with the aim to reveal human impact of experimental activities on Fishery transformation, which were conducted in 1969-1972. The study displayed small changes in higher aquatic plants’ composition: the number of macrophytes species almost haven’t changed, dominant species of emergent vegetation belt maintained their positions, and locations of species listed in the Red Data Book were unchanged. The strong negative impact fishery activities made only on Charophyta stretches, which has disappeared or their areas were much reduced in studied lakes. One of the reasons of small changes is that the lakes belong to macrophyte type, which are more resistant to anthropogenic influences.
A geomorphological approach for enhancing environmental management and conservation of landforms as protected nature objects in the Upper Daugava spillway valley
Authors: Muižniece Evita , Soms Juris
Published: June 2015

This paper describes the application of geomorphological approach for environmental management and conservation of landforms. Specifically, we discuss the contribution of geomorphological field survey and adapted matrix methodology (in combination with understanding of geology) to identification, study and evaluation of those abiotic nature elements which represent geological and geomorphological heritage. We describe a case study carried out in that part of the protected landscape area “Augšdaugava” which encompasses the Upper Daugava spillway valley. The study programme reported in this paper was realized to perform inventory of landforms and geological features for recognition of objects of particular interest in terms of including them in the list of protected nature monuments. After the field reconnaissance and survey of such objects in situ, the assessment based on several criteria like scientific, aesthetic and paleogeographic value, type, rareness, integrity and representativeness was performed. Obtained data is sufficient to make a well-founded selection of the abiotic nature elements and components of geodiversity, including geological and geomorphological features, e.g. particular landforms as protected nature objects, and to substantiate the need for their conservation. Hence, the output of performed study can be used for enhancing environmental management and conservation of nature diversity and values in this region.
The Importance of Geoheritage and Geo Top of the Charts in Environmental Studies
Authors: Kepalaitė Ingrida
Published: June 2015

scientifically the following categories are excluded: biodiversity, geoheritage, geodiversity, geo tops, nature objects and others. They are important from the scientific, aesthetic, tourism, cultural points of view. The aim of environment sciences has to be to analyse the categories exhaustively and to determine the conditions of protection.
The Visualizations Methods of Geometrical Forms in teaching of Civil Engineering Students
Authors: Veide Zoja , Strozheva Veronika
Published: June 2015

Development of spatial representation (the ability to imagine three-dimensional objects using flat pictures or drawings), skills of the intuitive decision of spatial problems and more meaningful use of CAD software are essential for qualified education of students. Visualization of geometric problems helps students to understand and to solve the given geometric tasks. The paper describes types of visualization of geometrical objects from graphic exercises of compulsory subject “Civil EngineeringGraphics”. This course is specified for Civil engineering undergraduate 2nd year students of Riga Technical university.

Performance of a breadboard model, creation of the given model using ArchiCAD and using augmented reality (AR) software are included in the course "Civil Engineering Graphics” assignments. The examples of the tasks of 3D modeling in learning process are presented in this article. AR application allows faster understanding of complicated spatial problems and relationships and was used to entertain the students during the studies. Before mentioned approach was enabled to develop spatial skills of students, facilitate the students to obtain more practical experience in solving graphic exercises and was supposed enhance the quality of graphic education.

 
Bioenergy Resources in Latvia
Authors: Melece Ligita , Krievina Agnese
Published: June 2015

The paper presents results of study aimed to evaluate issues of current development of bioenergy in Latvia, taking into account restrictions, which may affect future progress of main biomass sources. These restrictions are based on latest European Union (EU) regulations and recommendations; and worldwide concerns of scholars on sustainability, particularly environmental (e.g. biodiversity, ecosystem resilience, carbon sequestration) of bioenergy (biomass) development. The appropriate qualitative and quantitative research methods have been used in the process of study. The results of examination suggest that biomass possesses one of the greatest potentials for further increasing renewables production, particularly in Latvia. The characteristics and perspectives of main biomass sources’ development are assessed for compliance with the EU latest regulations, recommendations and policies, particularly Common Agricultural Policy (CAP) 2014-2020, and they demonstrate    [reveal?] several limitations. The restrictions under the CAP regulations’ so-called ‘greening’ requirements mainly affect the production of energy crops, limiting monocultures’ growing. For some types of biomass production (e.g. energy cultures, wood biomass), several limitations or restrictions are considered, in particular, those related to environmental issues such as biodiversity, soil properties, agro-ecosystems and landscape. Forest origin, non-food plants (e.g. perennial grasses) and different kind of residues and waste could be the most important, perspective and sustainable biomass sources in Latvia. Besides, the dominance of a single bioenergy source would be unsustainable in the long run, and diversifying of the energy system is preferred.
Analysis of emergency situations on the process of thermal power plants using mathematical apparatus of Petri nets
Authors: Trashchenkov Sergey , Egorov Vladimir
Published: June 2015

Article is dedicated to the issues of accident scenarios analysis on the process of thermal power plants. The theoretical foundations of the graphical and analytical representation of Petri nets are shown. The article describes the steam cycle process and listing of its technology protections. A state model for power unit equipment and technological protections under the influence of changes in critical process parameters (steam’s temperature, pressure, level) is presented. Conclusions about the plans for further work in this direction are proposed.  
Development of Automated Approaches for Hydropower Potential Estimations and Prospective Hydropower Plants Siting
Authors: Arefiev Nikolay , Nikonova Olga , Badenko Nikolay , Ivanov Timofey , Oleshko Vyacheslav
Published: June 2015

Hydropower potential studies usually include estimation of hydropower resources and creating propositions for hydropower development on study area. The current paper describes authors’ study, dedicated to development of methodological approaches and software designed for solving problems stated above. Process automation is achieved by using geographic information systems (GIS) and additional programs (Python language was used).

Hydropower potential estimation is the key element for understanding future prospects of hydropower development within the study area. The latest large-scale hydropower potential studies of Russian territories were held in 1940-1980. In those times, such researches were carried out almost without any automation, so calculation process was time-consuming. As a result, only hydropower potential of large and several medium-sized rivers was estimated; hydropower potential assessments of small rivers were conducted only using approximate approach.

Nowadays, implementation of technologies and software products, such as geographic information systems, contributes to development of methodologies, which can be used to automate business-processes in different scientific disciplines, including processes of hydropower potential estimation and prospective hydropower plants siting. In comparison with former studies, GIS allow to reduce labor work significantly and to perform analysis of large study areas and large number of streams (including small rivers) in relatively short time using up-to-date topographical, hydrological and hydrographical information.

Authors have developed and tested methodological approach and GIS-tools for automated hydropower potential estimation. Re-estimation of hydropower potential was fulfilled by the authors for the most part of Russia. The data for more than 10 000 river’s was compared to the results of prior studies (data, such as river basin area, annual river flow, hydropower potential). The gross hydropower capacity of rivers and gross hydropower potential were estimated as 350 GW and  3,07*103 TWh respectively.

The next step in hydropower potential studies is prospective hydropower plants siting. Authors developed methodological approach and GIS-tools to automate this process. The GIS-tools provide comparison of site alternatives based on their hydropower parameters; transport, infrastructure, electricity network proximity; topographic situation and other factors affecting site suitability. Algorithm of automation and results of the search siting are presented.
Sustainable Development Perspectives for Latvian Regions
Authors: Ābeltiņa Anna , Zvirgzdiņa Rosita , Zariņa Vita
Published: June 2015

Regional economies is a relatively young branch of economics, whose theoretical aspects started  to develop in the 20s and 30s of the previous century, but gained vivid manifestation in the EU Regional policy. Since the Rome Treaty (1957), the need for a coordinated community solution to regional problems and the correction of regional imbalances was also recognised in EU political documents. The end of the twentieth century was the beginning of important international political processes marked by the start of a new way of thinking. This new way was sustainable development. Sustainable development is a concept that has to combine economic growth with such a use of natural resources that benefits the society as a whole. The long-term development has three dimensions: environmental, economic and social. In this paper, the attention will be devoted to the influence of these dimensions on the regional development.

The aim of this paper is to provide a new viewpoint, as it may seem, related to well-known things that include such economic concepts as regional development and sustainable development and to evaluate sustainable development in Latvian regions. To achieve the aim, the following tasks were selected: to evaluate the theoretical background of regional economy, to examine the main indicators of regional development, and to prepare a regional development forecast. The following research methodology was used: literature review, graphical method, focus group discussions and logically constructive approach – for making judgements and result analysis; synthesis method – to combine the elements in a unified system; social research methods – to obtain the primary information and to carry out its verification. Conclusions: the main reasons for misbalanced regional development are the differences in employment, levels of income and investment. The research proposes solutions to promote balanced regional development.  
The role of collaboration municipality ─ regional university in sustainable tourism development: Case study of Dagda county
Authors: Silinevica Irena
Published: June 2015

Research of different studies related to collaboration municipality ─ university allows to establish a fact that it is very important for both partners and has distinctive forms. The core questions of this research are as follows: Is the regional university significant player in regional sustainable tourism development? What forms of collaboration among regional university and municipality are possible? The aim of this research is to examine the experience of regional university in sustainable tourism development in regional area. This research is performed on the illustration of collaboration among regional university (Rezeknes Augstskola ) and Dagda county, which is one of the 19-th rural county in Latgale region. A new approach to the collaboration municipality ─ regional university is offered taking into account the possibilities of regional university in improvement of human resources capacity, in improvement of municipality administrative capacity, and in development of sustainable tourism products. The offered approach was set up by taking into account the interests of all stakeholders in this area.
Geoecological marketing of tourist - recreational zones of cities territories
Authors: Kononova Maria J.
Published: June 2015

Now, practically  in the all territory of the Russian Federation and, in particular, in it’s Northwest federal region we can say about The Russian  Renaissance with strongly pronounced elements of eclecticism. It’s no coincidence, as the nature-innovative potential forces to think about investment many means on development of the real estate and tourist-recreational zones as a whole. Answering repeating questions, where are the most dangerous areas for an investment of means and for the business organization, in particular, in St.-Petersburg, even more often you are surprised to such questions, understanding that danger can proceed, first of all, from a geoecological situation on cities territories. We don’t have reservations and/or divisions of administrative areas by a principle poor/rich and/or our and another's areas. You can feel genuine pride from comprehension of our deep tolerance. Means, it was possible to accept all the best, to learn to understand associates, to appreciate friendly relations, to live, without giving in to minute tendencies and the imposed stereotypes introduced by market relations.
Assesment of urban sustainable development: example of Rezekne city
Authors: Litavniece Lienīte
Published: June 2015

Since 90s of the 20th century sustainable development has become a global issue which is receiving increasing attention. Successful sustainable development is only possible from the bottom to the top, which means that the human and environmental mutual relations must be taken into account not only on a global scale as a whole, but also focus on the much smaller territorial units.

The role of the city as the administrative territorial unit has significantly increased in recent years, the acknowledgment for that can be found in the European Union Cohesion Policy, polycentric development policy, spatial planning policy, etc., in the figures of the rapid population growth in urban areas, about joining of separate scientific disciplines in order to study current issues in the cities.

In sustainable development studies special attention is paid to mega cities or capitals, which have the most significant impact on the environment, based on certain key indicators - CO2 emissions, the amount of municipal solid waste generated in cities, etc.

The planning documents, that provide a picture of the specific urban sustainable development priorities, play an important role in ensuring sustainable development.

The aim of the article is to explore the sustainable development strategies of the city of Rezekne for 2013-2030 in conformity with the five dimensions of sustainable development and to assess the development possibilities of Rezekne.

During the study the sustainable development strategy of Rezekne for 2013-2030 was evaluated, strategic aims, long-term priorities, and actions were established. As a result, it was concluded that they meet all five dimensions of sustainable development, but in the strategy for these actions, it is necessary to focus on the essence of the concept of sustainable development, that meets the needs of the present without compromising the ability of future generations to meet their own needs [1].

The evaluation of current performance shows that the strategy of planned targets may not materialize and as a result have a significant impact on sustainable development, so it is necessary to make appropriate adjustments in the operational plans.
Impact of the company’s main budgeting objectives on the evaluation of importance of financial and non-financial indicators
Authors: Kotane Inta
Published: June 2015

Financial planning forms a basis for the company’s management and determines the company’s objectives; the achievement of these objectives is measured using financial and non-financial indicators. The main budgeting objectives affect the importance of financial and non-financial indicators, thus, contributing to the achievement of the goals. The topicality of the research is determined by the fact that the financial and non-financial indicators have been examined by many authors; however, there exist problems regarding their practical application, since still there is no a consistent approach to the measurement and evaluation of both the financial and non-financial indicators. The study is based on the author's previous theoretical research on the application of financial and non-financial indicators in the evaluation of business performance; as a result, the author has established the sets of financial and non-financial indicators that were used in conducting the practical research.

                The aim of the current research is to determine the impact of the main company’s budgeting objectives on the evaluation of importance of financial and non-financial indicators on the basis of the opinion survey of Latvian business persons and top-level employees. The Internet survey was used in the research, applying a random sampling method.

The research results indicate that the opinions in the groups of respondents regarding the main company’s budgeting objectives differ, and the correlations exist among the main budgeting objectives. Comparison of the impact of the main budgeting objectives on the importance level of the financial and non-financial indicators shows that the possible impact is more significant regarding the importance of the financial rather than non-financial indicators.
Impact of Microbiological Fertilizer Baikal EM-1 on Onion Growth in Greenhouse Conditions
Authors: Grantina-Ievina Lelde , Stanke Lasma , Ergle Guna
Published: June 2015

The microbiological fertilizer Baikal EM-1 contains lactic acid bacteria, photosynthetic bacteria, nitrogen fixing bacteria, Saccharomyces yeasts and microbial cultivation media. The aim of the present study was to evaluate the impact of it on onion grown in controlled greenhouse conditions.

In summer 2014 two trials with this product were carried out on onions in greenhouse conditions. Before planting onion bulbs were soaked in water with added fertilizer and growth substrate was watered with the fertilizer according to the instructions of manufacturer. During the vegetation period plants were watered with the fertilizer several times. Identical treatment was performed with water in the control plots. Different treatment schemes and growth substrates (neutralized peat and substrate for vegetables) were used in both trials. The main difference of the used substrates was in the content of mineral nutrients that was higher in the substrate for vegetables. In the second trial additional fertilization with ammonium nitrate was applied three times during the vegetation period. At the end of the trials the yield of onion leaves was estimated, as well as the length of leaves and their chlorophyll content was measured.

At the first trial the obtained yield of onion leaves was increased by 6.4 % and in the second by 8.2 % due to treatment with Baikal EM-1 but these differences were not statistically significant in comparison to the control plots. In general, the fertilizer increased all other measured parameters as well, including average length of leaves by 4.6 % and 1.3 %, the chlorophyll content by 5.0 % and 1.5 %, in the first and second trial respectively, and percentage of onions developing leaves increased by 13.2 % in the second trial. Only the last parameter showed statistically significant differences in comparison to the control. Additionally the growth of the onion was more even in the control treatment. In conclusion, the microbiological fertilizer Baikal EM-1 gave positive impact on onions in greenhouse conditions.
Effects of crop rotation and field management methods on weed density and species composition in the southeastern part of Latvia
Authors: Ņečajeva Jevgenija , Mintāle Zane , Dudele Ieva , Isoda-Krasovska Anda , Čūrišķe Jolanta , Rancāns Kaspars , Kauliņa Ilona , Morozova Olga , Spuriņa Liene
Published: June 2015

Integrated weed management (IWM) is a complex approach to weed control that is based on use of several different methods complementing each other, instead of relying on one single method, like chemical weed control. Weed control methods that can be used as parts of IWM strategy include mechanical weed control, application of herbicides, low tillage, changes in the rate and application time of fertilizers, use of undersown crops and crop rotation. Weed surveys were carried out in 2013 and 2014 in the southeastern part of Latvia. The aim of this study was to assess the effect of crop rotation and other field management practices on weed density and weed species composition using the data collected in the surveys. Survey was carried out in the arable fields of conventional farms within four different size categories. One of the significant factors that explained the variation of weed composition within a field was a proportion of cereals in crop rotation within a four year period. Further surveys are required to estimate the effects of climatic variables. Density-dependence can also be important for practical management decisions for particular weed species and should be investigated.
Yield development of flax varieties and lines within variable environment in Latvia
Authors: Stafecka Inga , Stramkale Veneranda , Grauda Dace
Published: June 2015

Flax is the multiple purpose crop cultivated in temperate region. Seeds of oil flax recently became important constituent for many industrial applications, such as pharmacy, medicine, food production etc. and have high prospective for use in Latvia. Understanding the underlying processes that limit seed yield in flax is major with respect to enhancing the breeding of flax for yield improvements. The aim of study was evaluated 29 flax varieties and lines (including 20 Latvian origins) plasticity of seed yield production in changeable environmental conditions. The experiment was carried out in the Agricultural Scientific Centre of Latgale on field trials over the period 2010-2013. The aim of this study was evaluated plasticity in changeable environmental conditions for 29 flax varieties and lines (including 20 Latvian origins). According to 4 years results was to establish the nature of relation between seed yield and hydrothermal coefficient (HTC), and seed yield and another yield components of flax. Apart from the changing conditions highest seed yield were produced from a varieties ‘Lirina’ (2.54 h -1t), high seed oil content from variety ‘Amon’ (53.03%). Positive and significant relationships were found between seed yield and HTC ‘T30-28-6-94’(r=+0.98*), ‘German Serenade’ (r=+0.95*) and ‘Scorpion’ (r =+0.95*).
The Nutrient Concentration in Drainage Water in Fertilizer Experiments in Skriveri
Authors: Vigovskis Janis , Jermuss Aivars , Sarkanbarde Daina , Svarta Agrita
Published: June 2015

The paper describes the influence of long term (more than 30 years) fertilizer application to nitrogen, phosphorus, potassium, calcium and magnesium leaching through subsurface drainage in small experimental catchment. The effect of crop and cultivation practice on nutrient concentrations in drainage water is analyzed. This paper presents leaching data during 2011-2013 when spring oilseed rape (OSR), spring barley (SB) and perennial grasses (GC) were grown.

The research has been carried out at the Research Institute of Agriculture of Latvian University of Agriculture in the long-term subsurface drainage field established in Skrīveri in 1981 under the guidance of professor J. Štikāns. The long-term drainage field was established in the uncultivated gleyic sod-podzolic Hypostagnic Endogleyic Albeluvisol (Hypereutric), stw-ng-AB(he) loam that had not been used in agriculture for 20 years before. The experimental field was established with four rates of mineral fertilizers: without fertilizers, N45P30K45; N90P60K90 N135P90K135 calculated in form of P2O5 and K2O. Since 1994 a seven-year crop rotation has been organized: 1) winter triticale, 2) potatoes, 3) spring wheat, 4) spring oilseed rape, 5) spring barley + perennial grasses (red clover, timothy), 6) perennial grasses, 1st year of using, and 7) perennial grasses 2nd year of using. The total area (1.6 ha) of the experimental field was divided into 16 plots (15x50 m). Each plot was supplied with a seepage tile drain at the depth of 80-100 cm and an inspection well for drain water sampling and measurement of total water amount.

The nitrate nitrogen content in subsurface drain water was significantly affected by fertilizer rate and crop species. The concentration of nitrogen in drain water was significantly lower from non-fertilised plots than from other treatments and was considerably lower growing grass without autumn soil tillage than with conventional ploughing. Different fertilizer rates (applying 30, 60 or 90 kg ha-1 of phosphorus and no fertilizer) had no significant effect on phosphorus concentration in drain water. However, concentration of potassium in drain water depended remarkably (p<0.001) on fertilization rate and was lower from non-fertilized plots. Without autumn ploughing and providing vegetation potassium leaching was significantly lower. The use of fertilizers increased the subsurface water concentration of calcium and magnesium considerably.
Trends of the culinary herbs diversity research and their use in green plantations
Authors: Budrienė Aušra , Buzienė Idalija , Margelienė Jolanta , Markevičienė Laima , Maročkienė Nijolė
Published: June 2015

In recent times, due to the globalization the fashion of plant cultivation has been changing as well; imported, decorative acclimatized culinary herbs have been penetrating, therefore, new tasks to integrate them into the traditional plantations have been arising.

The main aim of the paper is to select culinary herbs for the design solutions having different purpose and adapted to different environmental conditions, to reveal the possibilities to use the best properties of these plants, to help the persons interested in the use of culinary herbs to decide on the proper plant selection, to provide recommendations on the combination and composition possibilities of these plants.

The authors of the article have analyzed and evaluated the research carried out in Lithuania related to the issues of culinary herb cultivation. In the Institute of Horticulture Lithuanian Research Centre for Agriculture and Forestry 24 species of culinary herbs are cultivated. By analyzing the culinary herbs cultivation technologies, plant bio ecology and morphology as well as priority propagation techniques have been evaluated; decorative properties of herbs and the possibility of their use in green plantations have been assessed.
Pyrolysis of wild cyanophyta from Chaohu lake for bio-oil
Authors: Chen Jun , Ci Juan , Lai Wei Xin , Min Yu Zhi , Jin Jie
Published: June 2015

To solve the environmental problems caused by the algae, pyrolysis experiment was studied to produce bio-oil with the wild cyanophyta from Chaohu lake for the first time. The results showed that the suitable temperature, carrier gas flow rate, and the smaller particle size were better for liquid products generation, the liquid (bio-oil) yield obtained maximum (66 %) at temperature of 450 oC, carried gas flow rate of 50 mL/min and particle size of less than 0.25 mm. The main ingredients of liquid product from cyanophyta pyrolysis consisted of hydrocarbons, nitrogenous compounds, acids and other organic compounds (such as alcohols, phenols esters and non-identified materials). Acid content was the highest and greatly affected by temperature. The content of hydrocarbons was about 15%.
Neurons vs Weights Pruning in Artificial Neural Networks
Authors: Bondarenko Andrey , Borisov Arkady , Alekseeva Ludmila
Published: June 2015

Artificial neural networks (ANN) are well known for their good classification abilities. Recent advances in deep learning imposed second ANN renaissance. But neural networks possesses some problems like choosing hyper parameters such as neuron layers count and sizes which can greatly influence classification rate. Thus pruning techniques were developed that can reduce network sizes, increase its generalization abilities and overcome overfitting. Pruning approaches, in contrast to growing neural networks approach, assume that sufficiently large ANN is already trained and can be simplified with acceptable classification accuracy loss.

Current paper compares nodes vs weights pruning algorithms and gives experimental results for pruned networks accuracy rates versus their non-pruned counterparts. We conclude that nodes pruning is more preferable solution, with some sidenotes.
Fuzzy multiple criteria decision making approach in environmental risk assessment
Authors: Radionovs Andrejs , Uzhga-Rebrov Oleg
Published: June 2015

Being able to evaluate risks is an important task in many areas of human activity: economics, ecology, etc. In case of a sufficient amount of source information the risk is evaluated using statistical methods. However, in reality the sufficiency of statistical data in risk assessment is more exceptional than normal. In such cases experts’ assessment make the only source of data. Experts are able to provide the necessary for analysis data due to their professional knowledge and experience. Certain amount of factors, which is to be evaluated by an expert (experts), significantly affects the process of experts’ assessment. If a big number of relevant factors occur, an expert may face a problem of defining links between “factors” and “outcome”. Fuzzy multiple criteria decision making approach can be used to solve the problem. Ecological risk assessment towards human health in case of gaseous substances escape at a chemical factory using hierarchical method and fuzzy multiple criteria decision making approach has been analyzed in the article.
Using the Concept of Fuzzy Random Events in the Assessment and Analysis of Ecological Risks
Authors: Uzhga-Rebrov Oleg , Kuleshova Galina
Published: June 2015

In many cases, the assessment and analysis of ecological risks is a complicated task, which is first of all related to obtaining reliable initial information. As a rule, ecological risks are due to unrepeated unique situations; from this it follows that sufficient statistical data on whose basis reliable evaluation of specific risks is made, are not available. On the other hand, unfavourable impacts on the external environment can affect the components of an ecosystem differently. The complexity of correlations among the components of an ecosystem significantly complicates an analysis of possible impacts on the components of a specific system.

When statistical data are missing or insufficient, experts who perform the required assessment on the basis of their knowledge and experience but often also using their intuition, are the only source of initial data. Here, however, the problem of reliability of expert evaluations arises. If other sources of information are missing, we have to accept subjective evaluations of experts as a basis, without an opportunity to evaluate the degree of their confidence.

In this kind of situation, it seems to be validated to introduce the extent of uncertainty into the evaluations of parameters of ecological risks. This can be accomplished by using fuzzy initial evaluations. This paper focuses on the concept of fuzzy random events and shows favourable chances of using that concept in the assessment and analysis of ecological risks. 
Factors Affecting Attrition among First Year Computer Science Students: the Case of University of Latvia
Authors: Borzovs Juris , Niedrite Laila , Solodovnikova Darja
Published: June 2015

The purpose of our study was to identify reasons for high dropout of students enrolled in the first year of the computer science study program to make it possible to determine students, who are potentially in risk. Several factors that could affect attrition, as it was originally assumed, were studied: high school grades (admission score), compensative course in high school mathematics, intermediate grades for core courses, prior knowledge of programming. However, the results of our study indicate that none of the studied factors is determinant to identify those students, who are going to abandon their studies, with great precision. The majority of the studied students drop out in the 1st semester of the 1st year, and the dropout consists mostly of those, who do not really begin studies. Therefore, one of the main conclusions is such that the planned activities of informing about the contents of the program should be carried out, and the perspective students should be offered a possibility to evaluate their potential to study computer science before choosing a study program. 