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Offer and opportunities of logistics education in Latvia
2008
Radzele-Sulce, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
The goal of the research was to evaluate the opportunities in preparation of logistics specialists offered by Latvian universities and to formulate problem solutions. To achieve the goal, study programmes and course syllabuses offered by Latvian universities and colleges were analysed from the logistics perspective. Opportunities to acquire logistics knowledge offered in Latvia by distance, in further education and life-long learning programmes were reviewed. In the end, it was concluded that the development of logistics education in Latvia does not correspond to the speed of the development of logistics industry. Currently Latvia offers 4 Logistics study programmes, but only one study programme offers education corresponding to the professional standard – Manager of Logistics Department – as approved by the MoES. Latvia University of Agriculture currently has no logistics study programmes but different logistics subjects are included in the study programmes of 4 Faculties, therefore there are vast opportunities and it is necessary to develop the offer of logistics education, first by giving students the opportunity to choose specialisation in logistics in the Faculties in the study areas of which logistics is especially important and necessary – Faculty of Economics, Technical Faculty, Faculty of Forestry, Faculty of Food Technology, and Faculty of Agriculture.
Afficher plus [+] Moins [-]Forest change detection using knn (k-nearest neighbour)-based estimations of point-wise forest characteristics
2008
Jonikavicius, D., Lithuanian Univ. of Agriculture, Akademija, Kauno reg. (Lithuania)
This paper discusses the usability of non-parametric knn (k-nearest neighbour) method to detect changes in forest areas from satellite images. Spot Xi images acquired 1999, main forest characteristics from field measured sample plots and data of conventional stand-wise forest inventory from the year 1988 were used to estimate the grids of following forest characteristics: mean age of main forest storey, diameter, basal area, height, volume per 1 ha, as well as the percentages of coniferous, soft and hard deciduous tree species. The differences of grids, created using stand-wise forest attributes from the 1988 inventory and estimated using the k-nearest neighbour methods were experimented to detect changes in the forest. 68.7-75.5% of areas, classified as the potential felling areas, were detected to be clear cut areas or young stands less than 15 years according to the data of stand-wise inventory of year 2003. Different settings for the methods investigated are evaluated, too.
Afficher plus [+] Moins [-]The analysis of silver birch (Betula pendula roth.) stands in state and private forests in Latvia
2008
Zalitis, T., Latvia Univ. of Agriculture, Jelgava (Latvia)
In Latvia, birch is the second most widespread tree species; the share of birch is higher in private forests. The Forest Research Inventory that was launched in 2004 provides credible and up-to-date information about all forests of Latvia irrespective of the ownership. The data from first three years’ data base of this Project has been used in the present study. The aim of this study was to analyse birch stands in state and private forests concentrating on different aspects: mixture degree, origin of the stand, productivity and quality of the stand. 735 sample plots were selected from the database for the analysis. The proportion of the birch stands in the private forests was slightly higher than in the state forests. There were more mixed stands in the state forests than in the private ones. The standing volume was higher in the mixed stands while the opposite was true for the current annual volume increment of birch. The main regeneration method in both the state and private birch stands was natural regeneration from seed. Artificial regeneration was used only rarely in the private birch stands. The productivity did not differ significantly between the state and private forests; the same was true for the quality, expressed by the outcome of veneer logs. The stand quality differed significantly among site types, being the highest in the forests on dry mineral soils and the lowest in the forests on drained peat soils.
Afficher plus [+] Moins [-]Productivity of Norway spruce stands in state and private forests of Latvia
2008
Libiete, Z., Latvia Univ. of Agriculture, Jelgava (Latvia)
In Latvia, almost 50% of all forests are privately owned. Due to hard economic situation in the 1990ies, many private forests have suffered from illegal forestry operations and overexploitation. One of economically most important tree species for private forest owners is Norway spruce. In this study the productivity of state-owned and private spruce forests was compared, assuming that the stand productivity of private forests should be lower compared to those owned by the state. Data gathered in the Forest Resource Inventory in 2004, 2005 and 2006 was used for the analysis. Total standing volume of the dominant stand and the current mean annual volume increment (CMAI) of spruce were used as main productivity indicators. The mean values of the main stand characteristics were found to be rather similar in state and private forests. The only significant differences were discovered in the mean diameter and CMAI of spruce in 60-90 years old stands; in both cases the values were higher in private forests. Site type and mixture degree were tested as the possible influencing factors. Although there were differences in the site type distribution between state and private forests, the influence of this factor on the CMAI of spruce proved to be insignificant. It was found out that the CMAI of spruce depended significantly on the mixture degree. The proportion of mixed stands in the state forests was considerably higher than in the private forests; presumably therefore the value of the CMAI in the state forests was significantly lower.
Afficher plus [+] Moins [-]The effect of rainfall on activity of the sewage co-system in Riga
2008
Ziemelnieks, R., Latvia Univ. of Agriculture, Jelgava (Latvia) | Tilgalis, E., Latvia Univ. of Agriculture, Jelgava (Latvia) | Juhna, V., Latvia Univ. of Agriculture, Jelgava (Latvia)
The human influence on hydrological cycle has created many surface problems in the Riga city. Rainfall amount increases year after year as a result of global warming and bad water exchange. Solid covering of squares and greened areas is one of the most significant results of urban development causing larger rainwater runoff from the territories and calling for the necessity to drain rain water rapidly in a short time. This phenomenon is observed in the last years due to the fast construction development and simultaneous expansion and improvement of streets and court yards. The main problem matter is the still existing old sewage co-system which encounters difficulties to work with full capacity during long term rainfall. Thus justifiable steps have to be taken in order to discover new engineering solutions to prevent overflow of streets in Riga during rains. To enquire into the matter, rain intensity in Riga, influence of rainwater on streets, overflowing of collectors, and operation of pumping stations are studied in this paper. Rain intensity measurements during 1980-2006 in Riga have been aggregated. As acquired data shows, maximum rain intensity was observed on July 30 of 2005 when the rainfall was 49.4 mm during a 3-hour time, which caused overflowing of some streets, collectors, and pumping stations. Data on local and main pumping stations at the right bank of the river Daugava during various rainfalls suggest that pumping stations start to overflow during enduring rainfalls, 1-3 hours long and with average intensity of 0.1-0.4 mm minE-1 (Ziemelnieks, Tilgalis, 2008). Data gathered indicate, that it is necessary to separate sewage systems for everyday necessities from those for rainwater.
Afficher plus [+] Moins [-]Impact of the roughness coefficient for the hydraulic conductivity of regulated rivers
2008
Barvidiene, O., Vilnius Gediminas Technical Univ. (Lithuania) | Saulys, V., Vilnius Gediminas Technical Univ. (Lithuania)
The article presents hydraulic conductivity modelling results of the some regulated Southeast Lithuanian streams overgrown with woody vegetation. Possibilities to plan naturalization of the regulated streams are also presented in the article. The research of woody vegetation was carried out in the Neris river basin within the period of 2006 to 2007. Having evaluated the influence of hydraulic roughness (Manning coefficient of roughness) on hydraulic conductivity of the rivers Nemėža and Ž-2 streams it was established that the density of woody vegetation in the investigated section varied from 0.01 to 0.68 units m-2 in Nemėza stream and from 0.17 to 3.12 units mE-2 in Ž-2 stream. At the existing density of woody vegetation the hydraulic roughness coefficient n established by hydraulic calculations reached in 0.025–0.045 in Nemėža stream and 0.033–0.053 in Ž-2 stream. Under present hydraulic roughness coefficient assessed by natural investigations in all investigated streams sections, when spring flood discharge probability is 10%, water overflow indicator is positive; the water depth in the bed (zv) of the natural reaches was lower than the depth of a regulated stream (hG). The reserve of hydraulic conductivity in the investigated Nemėža stream section is lost when roughness coefficient reaches the limit of 0.080, in Ž-2 stream 0.060. When roughness coefficient reaches 0.170, water overflowing indicator is negative in all investigated sections of the streams.
Afficher plus [+] Moins [-]Investigations on ground water in the swine-breeding complex
2008
Miseviciene, S., Lithuanian Univ. of Agriculture, Kaunas (Lithuania). Water Management Inst.
The data on chemical composition of groundwater in the boreholes installed in the fields of a swine-breeding complex JSC Kontvainiai irrigated by liquid manure and in the production territory are presented in the article. This complex is situated on the Lithuanian coast, southeast of Klaipeda district. The data covers the period 2001-2005. It was established that the chemical composition of groundwater depends mainly on the soil. Ion sum was 2 times higher in the water of the well which was installed in the soil having a peat layer. The chemical composition of groundwater depended as well on its movement direction. As groundwater moves to the southeast, south and southwest from the fertilized area, the mineralization of water in wells 1 and 4 was the highest – 699 and 728 mg lE-1, respectively.
Afficher plus [+] Moins [-]Research of treatment of wastewater from milk collection stations in sand filter
2008
Askinis, S., Lithuanian Univ. of Agriculture, Kaunas (Lithuania). Water Management Inst.
Highly polluted wastewater accumulates in milk collection stations. Its biochemical oxygen demand (BOD5) ranges from 369 to 1388 mg O2 lE-1. The average contamination was 600 mg O2 lE-1. There was a comparatively small amount of biogenic materials in it: total nitrogen – 27.3, total phosphorus – 5.0 mg lE-1. When variations of wastewater amounts are high, sand filters of vertical filtration are successfully used for the treatment of household wastewater. Model investigations were carried out to establish the possibilities of using these filters in treating wastewater in milk collection stations. The efficiency of wastewater treatment with these filters was 99.3% by BOD5, 99.1% – by suspended solids, 91.2% – by total nitrogen and 98.8% – by total phosphorus. According to the research results dependency equations were made; they were used to calculate the amount of main contaminants in milk collection stations that infiltrated through a layer of silt of diff rent thickness. The calculations showed that wastewater treatment to permissible limits is ensured by filtration through 0.6 m thick layer of sand. The average treatment level by BOD5 in such a filter of vertical filtration would be 20 mg O2 lE-1 and the treatment efficiency – 95.9%. Treatment efficiency of total nitrogen would be 88.1%, total phosphorus – 96.9, suspended solids – 95.5%. Preliminary research in the model showed that sand filters of vertical filtration can be used to treat wastewater from milk collection stations.
Afficher plus [+] Moins [-]Modernisation of manure management technologies in large pig complexes of Lithuania
2008
Kazakeviciene, J., Lithuanian Univ. of Agriculture, Kaunas (Lithuania) | Struseviciene, S.M., Lithuanian Univ. of Agriculture, Kaunas (Lithuania). Water Management Inst.
Technologies of keeping livestock and management of manure pig complexes holdings built in the country under the Soviet regime no longer satisfy modern veterinary and environmental requirements. Conditions for the modernisation of such complexes were created as from 2000, when agricultural aid programmes (funds) appeared in Lithuania. Information about old and newly implemented manure management technologies, fertilisation value of manure, and quality of the drainage runoff from manure-fertilised fields has been collected in six large livestock companies. Analysis of collected data revealed that new livestock keeping, feeding and manure management technologies are more cost-effective in using energy and mineral resources and conform to the animal welfare, environmental protection and hygiene requirements that are becoming more and more stringent. As the traditional manure management in economic terms is quite expensive and has a significant impact on the environmental quality, academic community is looking for new manure processing methods. The global development of manure management technologies focuses on the manure processing in biogas plants. Biogas generated from liquid manure and animal waste in such plants is an alternative source of energy.
Afficher plus [+] Moins [-]Using of AnyLogic and ExtendSim in modelling of biofuel logistic systems
2008
Dukulis, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
Rising oil prices, national security concerns, the desire to increase farm incomes, and a host of new and improved technologies are propelling the European Union to set the directive for the year 2010 – each member state should achieve at least 5.75% biofuel usage of all used transport fuel. The report on the progress made in the use of renewable fuels shows that the average Member State of the EU has achieved only 52% of its target, and biofuels’ share in 2010 will not raise much above 4%. The prices of different biofuels are still not able to compete with oil based fuel prices. One of the possible ways how to solve this problem is to optimize biofuel supply chains using different methods of systems engineering. The aims of this investigation were finding out appropriate simulation tools for biofuel supply chain modelling, development of rapeseed oil supply chains for different production types, and modelling the developed supply chains. As the result of software survey, two packages were chosen – AnyLogic and ExtendSim Suite. Modelling studies showed that rapeseed oil supply chain is very sensitive, because changing just single parameters in a short scale, the actual cost price of 1 litre of oil changes considerably. Comparing the fossil diesel fuel prices with rape oil actual cost from modelling studies, the use of oil as a fuel for farm machinery seems to be profitable. Analysis of costs distribution shows that the greatest part is composed by rapeseed growing expenses.
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