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Internal stresses of biomass compositions
2005
Nulle, I.(Latvia Univ. of Agriculture, Jelgava (Latvia))E-mail:[email protected] | Kakitis, A.(Latvia Univ. of Agriculture, Jelgava (Latvia))
Relevant resources for biomass energy production are cereal straw residues and emergent vegetation from wetlands. This bulk herbaceous biomass is a material with low density. Density of briquetted straw and reed has been increased from 60 kg mE-3 to 1000 kg mE-3. The storage, dosage and mixing of biomass bulk materials before compacting are necessary, which requires working knowledge of the bulk properties of materials. The angle of repose of straw, reed and peat particles was investigated. It was stated that angle of repose of straw and reed varies between 45-55 degrees. The angle of repose of peat particles varies between 37-50 degrees. The stress ratio between horizontal and vertical stress is important for equipment design. This ratio was investigated for different size particles of straw, reed and peat. Stress ratio of straw particles varies between ~ 0.6-0.71.
Show more [+] Less [-]Steam water quality in the karst zone of Lithuania
2005
Rudzianskaite, A.(Lithuanian Univ. of Agriculture, Kaunas (Lithuania). Water Management Inst.)E-mail:[email protected].
The paper gives the data about the mineralization process (sum of ions) and the amount of nutrient ions (nitrogen, phosphorus) contained in water of two streams (basin areas 1.63 square km and 2.02 square km) located in soils of different texture in the karst zone. As the study results have shown, higher amounts of DIN (dissolved inorganic nitrogen) were determined under the conditions of higher humus content in the soil (more humus (0.8-3.0%) was observed in glacial lacustrine soils), uneven runoff distribution (when its formation process is interrupted), and increasing DIN concentrations in silt. N-NO3 purification coefficient in stream water was higher when the stream was flowing via non-drained wood-covered area, also under the conditions of higher air temperatures. TP (total phosphorus) concentrations contained in stream water mostly depended on large amount of precipitation (especially in summer) as well as on phosphorus contained in silt: higher P2O5 concentrations contained in silt determined lower TP concentrations in water (determination coefficient of the relation r**2=0.24-0.30).
Show more [+] Less [-]Accumulation of sludge during the treatment of wastewater from milk processing companies and its application as a soil fertilizer
2005
Steponavicius, A.(Lithuanian Univ. of Agriculture, Kaunas (Lithuania). Water Management Inst.)E-mail:[email protected]
The processing of milk in dairy companies produces a certain amount of wastewater and liquid wastes. During the treatment process of such wastes sludge is accumulated in treatment facilities. The sludge is a rather valuable soil fertilizer; however, apart from plant available nutrients, it also contains large amounts of pollutants. The paper analyzes the quality of wastewater treatment process performed in treatment facilities of dairy companies, and specifies the amounts of plant available nutrients contained in sludge accumulated during the treatment process of wastewater and liquid wastes. The amounts of heavy metals contained in sludge are compared with their maximum allowable concentrations determined in the environmental requirements for soil fertilization (Aplinkosaugos reikalavimai..., 2001). On the basis of the study results and normative documents of environment protection, the article presents optimal rates and regime for sludge fertilization as well as analyzes the agro-technical and qualitative characteristics of sludge spreaders made at the Water management Institute of Lithuanian University of Agriculture and used during the technological process of fertilization.
Show more [+] Less [-]Wastewater produced on dairy farms and its treatment efficiency in constructed wetlands
2005
Strusevicius, Z.(Lithuanian Univ. of Agriculture, Kaunas (Lithuania). Water Management Inst.)E-mail:[email protected] | Struseviciene, S.M.(Lithuanian Univ. of Agriculture, Kaunas (Lithuania). Water Management Inst.)
The paper presents the results of investigations on wastewater formation and its treatment in constructed wetlands (CW) with horizontal flow. The investigations were carried out on a dairy farm in the period of 1995-2004. On farmsteads containing cattle sheds, the pollution of wastewater is 2-3 times higher compared with domestic wastewater. The largest amount of slowly decomposing organic pollutants is retained during wastewater filtration via a septic tank (62.7% according to CODCr). During wastewater filtration through a horizontal CW, the amount of retained organic pollutants biochemical oxygen demand (BOD5) and chemical oxygen demand (CODCr) is 93.6%. During wastewater filtration through CW, nutrients (Ntotal and Ptotal) treatment efficiency on the dairy farms, where Ntotal concentration is 101.0 mg lE-1, is one the average 61.4% of nutrient load, and 41.4% of P where Ptotal concentration is 21.5 mg lE-1. The analyzed wastewater treatment facilities (septic tank + CW) are distinct for their buffering capabilities. They are affective enough, however due to limited P removal processes in sustainable natural environment, additional P-removal means are to be used in wastewater treatment facilities arranged on dairy farms.
Show more [+] Less [-]Investigation and evaluation of the state of protective belts and inflow of erosion products into drainage channels
2005
Ragauskas, S.(Lithuanian Univ. of Agriculture, Kaunas (Lithuania). Water Management Inst.)E-mail:[email protected]
As the result of the studies on the condition of protective belts of drainage channels (PB) have shown, due to improving maintained and mechanical damaged protective belts large amounts of erosion products contained in surface water inflows the channel bed. Disorderly condition of protective belts does not correspond to the requirements of environment protection. Mechanical damages are often related to unsustainable human activity in the adjacent zone of a drainage channel. According to the principles of soil occurrence in the channel bed, four groups of damages might be distinguished: soil entrance into the channel during the tillage of a protective belt; inflow of washout products from the basin; scours of protective belts and washout of turf flumes of surface water discharge. The most frequent damages enhancing the washout of flumes and inflow of erosion products are total or partial tillage of the protective belt of a drainage channel. From the point of view of erosion process, the inflow of erosion products from the basin is considered as the most dangerous damages, which is inevitable when the width of protective belt is insufficient, particularly in places with deep turf flumes arranged.
Show more [+] Less [-]Hydraulic capacity of vegetated drainage channels
2005
Poskus, V.(Lithuanian Univ. of Agriculture, Kaunas (Lithuania). Water Management Inst.)E-mail:[email protected]
The studies were carried out in two control profiles of the Graisupis ditch excavated 40 years ago and situated at the distance of 2.4 and 4.8 km from the outlet in the land of intensive farming in Kedainiai district. The study object contained mineral loam/sandy-loam soils on the flat relief. The areas of catchments in control profiles were 12.1 and 5.9 square km, the largest discharges of spring floods were 3.4 and 1.6 m**3sE-1. Cross-sectional parameters, grass characteristics and flow parameters were measured under the conditions of different discharges (6 replications in each control profile during the vegetation period and 4 replications in spring when the channel bed is clean). As the study results show, roughness coefficient of the grass-cowered channel bed increased up to 21 times, water tables were observed to be 20-40 cm higher, the outlets of the drainage were flooded up. Considering the average grass indices determined in control profiles, grass hydraulic resistance was calculated according to 4 formulas based on the scheme when grass cover resistance is estimated as the total resistance of separate obstructions. The difference of 22.3% between calculated results and natural measurements was determined. The formula estimating grass cover parameters as well as flow regime determined to be most suitable.
Show more [+] Less [-]Development tendencies of land market in Latvia in the framework of land use politics
2005
Dambite, D.(Latvia Univ. of Agriculture, Jelgava (Latvia))E-mail:[email protected]
Before Latvia initiated the transition to market oriented economies, large collective units, which had the right to use the land, used most of the land but were not necessarily the landowners. This situation provided a special starting point for the return to the market economy in the agricultural sector. The government of Latvia decided to implement restitution of land ownership rights to former owners basing on historical boundaries as a method to privatise and open the land market. There were two processes going on at the same time: the restitution of private ownership rights to land, and the break-up of collective productive units. The restitution processes are the starting point for the development of land markets. Moreover, it represents a necessary condition to open land market. However, the place at which this land market opening is occurring depends on the way each government implemented the land reform.
Show more [+] Less [-]Retail crediting in Latvia
2005
Ozolina, I.(Latvia Univ. of Agriculture, Jelgava (Latvia))E-mail:[email protected]
The necessity of the research is to determine by the fact in Latvia there is a strong growth in bank credit to the private sector like in several transition countries in Central and Eastern Europe. Its implications for macroeconomic development and financial stability can be ambiguous. The aim of the research is to find possible scenarios for positive credit (to private sector) growth implications for macroeconomic development and financial stability in Latvia. Attainment of the objective comprises analysis of available statistical data about Latvia, identification of factors affecting bank credit growth following up some recent researches and modelling scenarios how the credit growth could facilitate further economic development in Latvia. This paper presents only recent trends in bank credit to the private sector in Latvia and evaluates some of the factors affecting these trends. It does not provide updated practical models and scenarios because the research has been started only recently.
Show more [+] Less [-]Hedonic evaluation of wheat bread with berries marc
2005
Gailite, I.(Latvia Univ. of Agriculture, Jelgava (Latvia))E-mail:[email protected] | Strautniece, E.(Latvia Univ. of Agriculture, Jelgava (Latvia))
The aim of the present study was to investigate the application possibilities of berries marc in wheat bread making to improve its quality. Sensory evaluation was used to determine the liking degree of bread with berries marc. Twenty samples of wheat bread with raspberries, white currants, gooseberries and seabuckthorn marc were produced by using standard technology. A 9 point hedonic scale was used to find out the degree of liking. The sensory data were analyzed using analysis of variance (ANOVA) and Tukey's test. The results of hedonic scaling show that berries marc (5-10% of the flour mass) can be used in baking wheat bread.
Show more [+] Less [-]Beta-glucan in hydrolysed soluble and insoluble oat fractions
2005
Gramatina, I.(Latvia Univ. of Agriculture, Jelgava (Latvia))E-mail:[email protected] | Kreicbergs, V.(Latvia Univ. of Agriculture, Jelgava (Latvia))E-mail:[email protected]
Oats contain more beta-glucan (2-7%) than other croppers. Beta-glucan is the most essential water-soluble dietary fibre. It lowers cholesterine level in blood as well as stimulates elimination of carcinogens from the body. In order to enlarge possibilities of use of oats in a diet, they can be separated in water-soluble and insoluble fractions. The aim of the present study is to determine the amount of beta-glucan in hydrolysed oat soluble and insoluble fractions. Gelatinized, hydrolysed and steeped oatmeal prior to hydrolyse, which was separated in water-soluble and insoluble fractions, was used in experiments. Not more than 6% of gelatinized (non-hydrolysed) oatmeal dry matter dissolved in water. The outcome of fermentative hydrolysed dry matter of water-soluble oatmeal was 40-52%. The content of beta-glucan in soluble and insoluble oatmeal fraction was determined by using McClearly method. The content of beta-glucan fraction of gelatinized oatmeal decreased for 78% in comparison to the content of beta-glucan in oatmeal used in the experiments. The content of beta-glucan in the soluble fraction of hydrolysed oatmeal decreased for 8.1% to 9.2%, and increased for 35-42% in the insoluble fraction if compared with the content of beta-glucan in oatmeal.
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