Lithuanian University of Agriculture

www.asu.lt
Kaunas, Lithuania

Aleksandras Stulginskis University is a university in Lithuania, in Akademija, west of Kaunas. It was renamed from Lithuanian University of Agriculture in 2011. Wikipedia.

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Rupsys P.,Lithuanian University of Agriculture
AIP Conference Proceedings | Year: 2015

A system of stochastic differential equations (SDE) with mixed-effects parameters and multivariate normal copula density function were used to develop tree height model for Scots pine trees in Lithuania. A two-step maximum likelihood parameter estimation method is used and computational guidelines are given. After fitting the conditional probability density functions to outside bark diameter at breast height, and total tree height, a bivariate normal copula distribution model was constructed. Predictions from the mixed-effects parameters SDE tree height model calculated during this research were compared to the regression tree height equations. The results are implemented in the symbolic computational language MAPLE. © 2015 AIP Publishing LLC.


Bhandari S.,Lithuanian University of Agriculture
CEUR Workshop Proceedings | Year: 2017

Opportunistic network is a new class of wireless network. This network is based on store-carry-forward mechanism. An architecture and functionality are different from another wireless network such as wireless sensor network or mobile ad hoc network. Unlike mobile ad hoc network opportunistic network do not need end to end path between source and destination nodes for providing communication between them. In this paper, methodology for enhancement in opportunistic network is proposed and implement by using network simulation. Multi-hop relay technique and Virtual-ID used together to enhance the performance of opportunistic network and at last performance of opportunistic network is analyzed by using three different cases in opportunistic network. Copyright © 2017 held by the authors.


Balezentiene L.,Lithuanian University of Agriculture | Streimikiene D.,Mykolas Romeris University | Balezentis T.,Lithuanian Institute of Agrarian Economics
Renewable and Sustainable Energy Reviews | Year: 2013

Both strategic and environmental factors make biomass an important energy source and element of sustainable energy policy. The establishment of a reasonable energy crop-mix, indeed, involves various uncertain data. This paper, therefore, offers a multi-criteria decision making framework for prioritization of energy crops based on fuzzy MULTIMOORA method which enables to tackle imprecise information. Given the appropriate energy crop-mix should exhibit both climatic suitability and low environmental pressure, we have defined the indicator set covering respective linguistic and numeric indicators. Accordingly, the set of alternatives were constructed from energy crops suitable for the Lithuanian climate. The fuzzy MULTIMOORA method was employed for data fusion and prioritization. As a result, the prospective species for energy crop-mix were suggested. © 2012 Elsevier Ltd.


Streimikiene D.,Vilnius University | Balezentis T.,Lithuanian Institute of Agrarian Economics | Balezentiene L.,Lithuanian University of Agriculture
Renewable and Sustainable Energy Reviews | Year: 2013

The aim of the paper is to assess energy technologies in road transport sector in terms of atmospheric emissions and costs and to indicate the most competitive and environmentally friendly transport technologies. The main tasks of the paper are: to develop the multi-criteria framework for comparative assessment of energy technologies in road transport and to apply MCDM methods for the transport technologies assessment. One of the MCDM methods, viz. the interval TOPSIS method, is employed in order to tackle the uncertain criteria. The assessment framework allows comparing road transport technologies in terms of their environmental and economic impacts and facilitates decision making process in transport sector. The main indicators selected for technologies assessment are: private costs and life cycle emissions of the main pollutants (GHG; particulates, NOx, CO, HCs). The ranking of road transport technologies based on private costs and atmospheric emissions allowed prioritizing these technologies in terms of environmental friendliness the lowest costs. However the extent, capacity, and quality of road infrastructure affects the overall level of transportation activity, which in turn affects how much energy is consumed by vehicles and the amount of greenhouse gases (GHG) emitted. The paper presents the impact of transportation infrastructure on GHG emissions from road vehicles and policy implications of performed assessment. © 2012 Elsevier Ltd.


Raslavicius L.,Lithuanian University of Agriculture | Bazaras T.,Kaunas University of Technology
Energy | Year: 2010

In this article, diverse liquid biofuels of the first generation were compared as partial or infant substitutes for fossil diesel fuel applied in cogeneration plant of the average capacity of 340 kW. The study concentrates on agricultural and economic conditions as well as legislative basis distinctive to Lithuania. At the laboratory of the Lithuanian University of Agriculture Institute of Agro-Engineering an experimental diesel engine powered generator was fuelled with rapeseed oil methyl ester (pure and in the blend with fossil diesel and dyed diesel fuels) and rapeseed oil with excellent energy balances and emissions characteristics more favorable than fossil diesel. Detailed estimations were proposed in order to assess the economic feasibility of complementing renewable electricity and heat generated in the final output cycle. The carried out analysis showed, that good perspectives are forecasted for using diesel engines in cogeneration plants, if they run on rapeseed oil produced by farmers themselves. The operation of such a plant would realize 184960 € of annual income for sold electricity, allowing to pay annual depreciation expenses and exceed the production cost for thermal energy to be 0.033 €/kW h. This price lies under the established one by the centralized energy suppliers, accordingly 0.058 €/kW h. © 2010 Elsevier Ltd.


Raslavicius L.,Lithuanian University of Agriculture | Bazaras Z.,Kaunas University of Technology
Fuel Processing Technology | Year: 2010

By the method of data collation, research into changes in life histories (ignition delay plus time of combustion) of the compounded fuel droplets (diesel fuel-biodiesel fuel (RME)-bioethanol), as well as diesel engine D-144 brake specific fuel consumption rates was performed and obtained results being compared to diesel fuel by an analogous manner. An optimum composition of the multi-component blend B30+7.5E demonstrating specific fuel consumption rates and droplet combustion characteristics very similar to diesel fuel was derived. In comparison to B30, a newly derived combustible blend demonstrated fairly improved emissions of exhaust gases. For low load mode: smoke opacity (-10%), NOX (-2%), CO (-20%), and HC (-12.5%). For average load mode: smoke opacity (-10%), NOX (-2%), CO (-22%), and HC (-14.5%). For high load mode: smoke opacity (-18%), NOX (-2%), CO (-22%), and HC (-18%). © 2010 Elsevier B.V. All rights reserved.


Balezentiene L.,Lithuanian University of Agriculture
Allelopathy Journal | Year: 2012

Assessment of the total phenols content (TPC) and biochemical impact of H. sosnowskyi on perennial ryegrass (monocots) and winter rapeseed (dicots) seed germination was done ex situ. Aqueous extracts of 2-yr old H. sosnowslyi exhibited higher phytotoxicity than 1-yr. old plant extracts. The phytotoxic effects of H. sosnowskyi aqueous extracts on the germination depended extract concentration (0.02- 0.2%), plant age (1-year, 2-year), plant parts (shoot: stem, leaf, blossom, seed; root) and growth stage (rosette-ripening). The phytotoxicity of H. sosnowskyi determined extract was most strong at flowering stage due to highest TPC (30.42 mg ml-1). All parts of H. sosnowskyi produced phenolics, which inhibited the acceptor-species seed germination. The results suggested that invasive plant species may acquire spreading advantage in new territories through use of their allelochemicals to inhibit germination. Nonetheless, species evidence for allelopathic effects should not be restricted to analysis of the plant extracts in the lab, but also include research in natural environment.


Labeckas G.,Lithuanian University of Agriculture | Slavinskas S.,Lithuanian University of Agriculture | Mazeika M.,Lithuanian University of Agriculture
Energy Conversion and Management | Year: 2014

The article presents the test results of a four-stroke, four-cylinder, naturally aspirated, DI 60 kW diesel engine operating on diesel fuel (DF) and its 5 vol% (E5), 10 vol% (E10), and 15 vol% (E15) blends with anhydrous (99.8%) ethanol (E). An additional ethanol-diesel-biodiesel blend E15B was prepared by adding the 15 vol% of ethanol and 5 vol% of biodiesel (B) to diesel fuel (80 vol%). The purpose of the research was to examine the influence of the ethanol and RME addition to diesel fuel on start of injection, autoignition delay, combustion and maximum heat release rate, engine performance efficiency and emissions of the exhaust when operating over a wide range of loads and speeds. The test results were analysed and compared with a base diesel engine running at the same air-fuel ratios of λ = 5.5, 3.0 and 1.5 corresponding to light, medium and high loads. The same air-fuel ratios predict that the energy content delivered per each engine cycle will be almost the same for various ethanol-diesel-biodiesel blends that eliminate some side effects and improve analyses of the test results. A new approach revealed an important role of the fuel bound oxygen, which reflects changes of the autoignition delay more predictably than the cetane number does. The influence of the fuel oxygen on maximum heat release rate, maximum combustion pressure, NOx, CO emissions and smoke opacity of the exhaust is highly dependent on the air-fuel ratio and engine speed. Fuelled with blend E15B the diesel engine develops the brake thermal efficiency of 0.362, i.e. the same as a straight diesel running on slightly richer air-fuel mixture λ = 1.5 at rated 2200 rpm speed. Adding of the ethanol to diesel fuel reduces the NOx and the HC emissions for richer combustible mixtures whereas the influence of a higher ethanol mass content on CO emissions and smoke opacity depends on the air-fuel ratio and engine speed. © 2014 Elsevier Ltd. All rights reserved.


Labeckas G.,Lithuanian University of Agriculture | Slavinskas S.,Lithuanian University of Agriculture
Energy Conversion and Management | Year: 2013

The present work focuses on the performance and emissions characteristics of a diesel engine operating on synthetic diesel fuel produced according to the Alphakat (KDV) technology. The purpose of the research was to examine the influence of the fuel of a new origin on the autoignition delay, cylinder gas pressure, brake thermal efficiency (bte), brake specific fuel consumption (bsfc) and emissions characteristics when running the engine on normal diesel fuel (DF) and KDV synthetic diesel fuel (SDF) over a wide range of loads and speeds. The bench tests were conducted on a naturally aspirated, four-stroke, four-cylinder, direct injection (60 kW) diesel engine D-243. When KDV synthetic diesel fuel was used the autoignition delay increased by 4.3° crank angle degrees (CADs), the beginning of combustion occurred 4.2°later and the maximum cylinder pressure increased by 1.8% compared to conventional diesel operation. The relative standard deviation (RSD) of pmax was 3.5-1.4 times higher for corresponding loads at rated speed of 2200 rpm. The maximum brake thermal efficiency decreased by 1.6% and 4.0%, and the minimum bsfc values increased by 2.6% and 4.5% compared to the normal diesel running at respective 1400 and 2200 rpm speeds. The maximum NOx emissions were 3.0% and 12.8% higher when running on KDV fuel than those, 13.3 g/kW h and 10.9 g/kW h, generated by the normal diesel at speeds of 1400 and 2200 rpm. Respective ratios of the NO2/NOx were 4.6% and 4.0% for KDV synthetic fuel, and 4.8% and 2.9% for normal diesel fuel. The CO and HC emissions generated by KDV synthetic diesel fuel were 30.8% and 8.3% higher as against those, 2.6 g/kW h and 1.2 g/kW h, produced by the normal diesel running under full load at rated 2200 rpm speed. As beneficial trade off, KDV synthetic diesel fuel suggested the maximum smoke opacity 21.7% and 14.0% lower at respective speeds of 1400 and 2200 rpm. © 2012 Elsevier Ltd. All rights reserved.


Pilipavicius V.,Lithuanian University of Agriculture
Journal of Food, Agriculture and Environment | Year: 2012

The allelopathic-phytotoxic influence of quack-grass (Elytrigia repens) overground and rhizome biomass water extracts on grain germination and early growth of spring wheat (Triticum aestivum L. variety SW Estrad C2) was investigated in laboratory experiments. After grinding, 50 g air-dried plant part (overground or rhizomes) was stirred into 500 ml of distilled water and left for 24 h at room temperature. Filtered water extract was taken as a stock solution, which was applied in 2-, 5- and 10-fold dilution, distilled water application served as control treatment. The spring wheat grain germination was checked after 5 and 11 days of sprouting using 5, 10 and 15 grains per Petri dish as different concentration of recipient plant, also, after 11 days of sprouting spring wheat seedling and radicle lengths were measured. Elytrigia repens rhizome water extracts showed higher inhibitory effect on spring wheat grain germination and early growth than water extracts of overground part. Elytrigia repens overground part water extracts of low concentrations had tendency to increase spring wheat grain germination. Spring wheat grain germination decreased till 1.7 and 2.4 times in Elytrigia repens overground part and rhizome stock solution accordingly. Spring wheat grain sprouting time after 5 or 11 days showed similar tendencies of grain germination with slightly higher germination after 11 days of sprouting. Increasing concentration of recipient plant, spring wheat grain number from 5 to 10 and 15 grains per Petri dish, did not have essential influence on its germination. Elytrigia repens overground part and rhizome water extracts initiated spring wheat seedling length growth. Spring wheat grain radicle growth was inhibited only in Elytrigia repens overground part stock solution. Increasing concentration from distilled water to stock solution of Elytrigia repens rhizome water extract the radicle length of spring wheat regularly decreased.

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