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Research methodology of cutting processes of aspen wood Full text
2013
Abele, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Tuherm, H., Latvia Univ. of Agriculture, Jelgava (Latvia)
Machining of wood of soft deciduous trees is currently based on the knowledge about cutting of wood of hard deciduous and coniferous trees and has not developed a comprehensive research methodology of cutting processes. Therefore, the objective of the study is a development of methodology for longitudinal sawing with circular saw and straight milling that would be utilized with a purpose of acquiring further knowledge on wood cutting and the improvement of cutting tool designs. Sub-objective of the study is determination of duration of cutter’s wear periods when using developed methodology. For the purpose of solving problems regarding cutting process of soft deciduous wood, the optimization of cutting tools and cutting modes were carried out in conditions that comply with the tendencies of the practise. The cutting process was carried out by a computer numerical control machine and the data acquisition by electronic measuring instruments. Aspen (Populus tremula L.) wood was used for wood samples. The methodology was developed for sawing, which complements the authors previously described methodology of the milling process investigations. Initially, only the results of periods of cutter wear and cutting velocity effects on these periods when milling process is used were obtained. It was concluded that the methodology can be used for further investigations and the critical wear period begins two times later when cutting velocity increases twice.
Show more [+] Less [-]In-situ phytoremediation: a review of natural and chemically assisted phytoextraction Full text
2013
Kasiuliene, A., Aleksandras Stulginskis Univ., Akademija, Kauno reg. (Lithuania) | Paulauskas, V., Aleksandras Stulginskis Univ., Akademija, Kauno reg. (Lithuania)
There are about 3,000-4,000 heavy metal contaminated sites across Lithuania. According to Lithuanian legal framework, the only way to manage this pollution is ex-situ cleaning which requires excavation, transporting, storage place and later monitoring. This indicates the urgent need of innovative technologies that would be not only costeffective but also environmentally friendly and have a public acceptance. Such technologies are natural and chemically enhanced phytoextractions. Both technologies incorporate plants that can accumulate excessive amounts of heavy metals. During continuous phytoextraction plants accumulate heavy metals throughout all vegetation period and are harvested together with heavy metals when desired biomass is gained. At chemically assisted phytoextraction metal binding chelates are added to increase heavy metal uptake by plants. Since phytoextraction is considered as promising green technology, many efforts are laid to find the most suitable hyperaccumulator plants as well as ecologically safe chelating agents. This paper intends to overview latest researches done at phytoextraction field and look over this kind of remediation possibilities in Lithuania.
Show more [+] Less [-]The design guideline for therapeutic sensory gardens Full text
2013
Balode, L., Latvia Univ. of Agriculture, Jelgava (Latvia)
The research topic is sensory, healing, rehabilitation and horticultural gardens, and the related discourses. The first part of the paper describes the historic development of the rehabilitation and health gardens in Latvia. Then he research paper takes a look at the main aspects which dominate in the rehabilitation and sensory visual and functional garden sites in the world. The quest to create contemporary landscape sites for health reasons is still one of the main subjects to explore and find definitions for. The methodology used in this paper is descriptive, from the perspective of historical relaxation gardens and health sites. The aim of this research is to define the main development lines of health sites in Latvia, trying to answer such questions as: How we can start developing sensory gardens and what is needed for their development in the future? To achieve the goal, it is necessary to absorb the world experience and exchange best practices, find innovative solutions, and adapt advanced rehabilitation center area landscapes to individual needs. When creating the healing gardens, the aesthetic and functional criteria have to be applied. Depending on the availability of the natural environment, health and satisfaction will be enhanced.
Show more [+] Less [-]The effect of timber properties on the behaviour of bending elements under loading Full text
2013
Brokans, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
Timber structure is a very complex system with its own specific character that causes a lot of difficulties for designers to predict its precise behaviour under loading. Timber construction behaviour under load is affected by many factors that in most cases influence timber constructions in a negative manner. Part of these influencing factors are properties of material, the other are components of the environment where the timber construction is located. This paper presents the results of experimental research where seventeen softwood (Pinus sylvestris L.) timber beams of rectangular cross section were tested in four point bending under long-term load in uncontrolled microclimate conditions (unheated building, all year round weather in the region of Latvia). Values of mechanical properties (modulus of elasticity), physical properties (density, amount of latewood, number of annual rings in 1 cm of wood) were measured at the start of the test; while monitoring of moisture content of wood, relative humidity and air temperature were performed simultaneously for the whole period of test. It has been observed that the main factors that significantly influence timber beam behaviour during period under load in natural climatic conditions are modulus of elasticity (MoE), density of wood and number of annual rings per 1 cm of wood. Amount of latewood showed an insignificant impact on timber beam behaviour under load.
Show more [+] Less [-]Wind-wave relationship: a case of the Lithuanian coast of the Baltic Sea Full text
2013
Kasiulis, E., Aleksandras Stulginskis Univ., Akademija, Kauno reg. (Lithuania) | Punys, P., Aleksandras Stulginskis Univ., Akademija, Kauno reg. (Lithuania)
In this paper regression analysis was adopted to assess the wind-wave relationship between wind speeds and wave heights on the Lithuanian coast of the Baltic Sea. In the coastal observations register missing data of visual wave observations occur because of the fog, ice, evaporation or other meteorological phenomenon. There is also inconsistency in instrumental measurements of wave heights in the Lithuanian coast due to technical issues. First step to fill the gaps in the wave height data is to find a strong relationship between wind speeds and wave heights. In this study correlation coefficients for Nida and Klaipeda coastal hydrometeorological stations data both taking and not taking into consideration wind blowing directions were calculated. Every data set used in this study was treated separately and it was revealed that applying nonlinear regression the most common model for wind-wave relationship analysis on Lithuanian coast is DR-Hill model, while applying multivariable regression it is Full Cubic model. Relationship between wind speeds and wave heights always can be improved by removing swell waves from correlation.
Show more [+] Less [-]Grishanin factor as criterion for river stability estimation Full text
2013
Vaikasas, S., Aleksandras Stulginskis Univ., Akademija, Kauno reg. (Lithuania) | Baublys, R., Aleksandras Stulginskis Univ., Akademija, Kauno reg. (Lithuania)
The article presents the natural and regulated stream bed stability and self-regulation issues. River beds equilibrium patterns are defined by Lane principle, observed in natural beds, while this balance is disturbed in regulated ones which has been confirmed by research. Natural and regulated rivers stability was evaluated by beds hydrodynamic stability criteria. It showed that the investigated natural rivers bed is stable enough. Under accumulated silt particle sizes in natural river beds, the formation regularities of meanders were determined. The investigated river meanders patterns confirmed the formation of natural river meanders characterizing patterns. It was found that regulated Lithuanian streams through self-beds meandering are useful not only for the natural diversity formation, but also increase meandering bed sediments conveyance capacity and stability from 3 to 3.5 times. Adapting to these naturally occurring processes and using the extensive channel maintenance techniques, it is possible to force the disruption of regulated streams hydrodynamic equilibrium self-recovery and biodiversity. The aim of research - according to the selected river bed hydrodynamic stability criteria to perform comparative analysis of stability of regulated and natural streams.
Show more [+] Less [-]The cycles of phosphorus in crop rotations differing in fertilization Full text
2013
Guzys, S., Aleksandras Stulginskis Univ., Akademija, Kauno reg. (Lithuania)
The investigations were carried out during the period 2006-2011 in the land of the Water resources management institute of ASU, in the village of Lipliūnai on Endocalcari Endohypogleyic Cambisol (CMg-n-w-can). The base of investigations is 3 drainage systems, which contain cereals differing in fertilization and grass crop rotations. The aim of investigations is to determine the crop rotations differing in fertilization and these relations with cycles of phosphorus in agroecosystem. Higher productive was perennial grass crop rotation. In the conditions of cereal crop rotations this productive was 3-46% lesser. The highest concentration of P-PO4 3- in drainage water was received in the conditions of higher fertilization cereals crop rotation while highest concentration of total P was in the conditions of grass crop rotation. The concentration of P-PO4 3- in drainage water essentially depends on amount of mobile P2 O5 in soil, fertilization, productivity of field crops, drainage runoff as well as cumulative balance of P. The highest leaching of P-PO4 3- and total P by drainage was received under the conditions of higher fertilization cereals crop rotation. The leaching of P-PO4 3- essentially depends on fertilization, drainage runoff as well as cumulative and yearly balance of P. The application of all crop rotations was distinguished by positive P balance.
Show more [+] Less [-]Geographical trends in export market of Latvian fisheries production Full text
2013
Berjoza, A., University of Latvia, Riga (Latvia) | Paiders, Ju., University of Latvia, Riga (Latvia)
Since joining the European Union Latvian fish industry has undergone a serious process of change and reform. Not all of them were welcomed by people working in the industry or those related to it. Consequently, the reform backed by the European institutions and legislature changed the dynamics and consistency of Latvian fish industry. As of 2004 many Latvian fishing vessels were scraped and even greater number of smaller fishing boats followed the same fate. Fishing and processing of the catch for Latvian shore regions is not only one of common and basic occupations, but also provides a large spectre of other services, as fishing in general is a complex industry providing a lot of jobs for seashore residents, primarily in primary, and secondary sectors of economy, and in smaller extent in tertiary, more precisely in distribution, trade and food services. This paper focuses on a research conducted on the expansion of Latvian fish industry product export market from a spatial, geographic perspective and analyzes the volumes and directions of outflow of goods to the recipient countries worldwide in period from 2000 to 2011. The analysis was done using correlation of yearly cargo flows and the spatial relations of major export directions, by historic and modern economic tendencies of the industry. Results give a picture of modern trends in export market geography and its changes during the first decade of the new century that is the ongoing transformation of East-oriented processed goods market into diverse one, which in future will largely depend on Western countries.
Show more [+] Less [-]Food wastage problems in a perspective of eating habits: a review paper Full text
2013
Tokareva, T., Latvia Univ. of Agriculture, Jelgava (Latvia)
Even though thousands of people suffer from hunger each day, there are people that simply throw away their food, imposing serious environmental, social and economic consequences. Food waste concept, however, is not as strictly defined as it varies from research to research. The classification itself can be specific to certain regions and cultures, and it can even be affected by the eating habits of the researchers. This review paper aims to unify the theoretical knowledge of food wasting with examples from actual research, evaluating data from the perspective of eating habits and finding motives for such an action, such as family and friends’ influence, incomes, lifestyle, religion, mass media etc. Previously done studies show that people are less concerned about reducing food wastage when it comes to environmental and social problems, but are the most motivated if they see a real opportunity to save money.
Show more [+] Less [-]Influence of sowing type, time and rate on the buckwheat yield forming elements Full text
2012
Vilcans, M., Latvia Univ. of Agriculture, Jelgava (Latvia);Latvian Plant Protection Research Centre, Riga (Latvia) | Volkova, J., Latvian Plant Protection Research Centre, Riga (Latvia) | Gaile, Z., Latvia Univ. of Agriculture, Jelgava (Latvia)
There is a lack of an actual information concerning cultivation of buckwheat (Fagopyrum esculentum), on the best methods of sowing and seeding rates. The aim of the study was to investigate changes in the buckwheat yield forming elements depending on sowing type, time and rate. Trials were established in farm “Araji”, Kraslava area, during 2010. Previous crop was spring barley. Buckwheat cultivar ‘Aiva’ was used in the field trial. Sowing was done on six different dates – May 15, 20, 25 and 30, and June 4 and 9. Two different types of sowing were used – drill sowing, with 4 sowing rates 200, 300, 400, 500 fertile nutlets per 1 m2, and the column sowing with the three sowing rates 150, 250, 300 fertile nutlets per m2. Data analyses were run using MS Excel Two factor analyses of variance. Time of sowing and seed rate had a significant influence on the buckwheat yield forming elements. Evaluating the performance of plant density at column sowing, it was found that plants survival rate was higher than that in drill sowing. The highest individual productivity of the plant was observed in plots sown in columns. The yield of buckwheat was on average 30-50% higher in the plots that were sown from June 4th to 9th if compared to those sown from May 15th to 20th, i.e. earlier sowing times were not the most suitable for buckwheat sowing in 2010.
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