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Influence of the hydraulic load on the wastewater treatment efficiency in the filters with different filter media
2010
Kazakeviciene, J., Lithuanian Univ. of Agriculture, Akademija, Kauno reg. (Lithuania) | Askinis, S., Lithuanian Univ. of Agriculture, Vilainiai, Kedainiai (Lithuania). Faculty of Water and Land Management. Water Research Inst.
In order to avoid the problem of stoppage in the filters of vertical filtration, we tried to search for the filter media which was coarse and could clean the wastewater to the allowable contamination level. For this purpose the dolomite chippings were chosen and the modelling investigation was performed. Two modelled filters taking 0.2 square m area each were equipped: one was filled with the sand and the other was filled with the dolomite chippings. The results revealed that the initial contamination of the wastewater had a much bigger influence on the wastewater cleaning process than the hydraulic load. The wastewater was cleaned with the efficiency of 95.9% and never exceeded the allowable level of 30 mg O2 LE-1 in the dolomite chippings filter during the trial with the hydraulic load 0.03 m**3 mE-2 dE-1. When the hydraulic load was doubled the efficiency of the wastewater cleaning process decreased to 80.5% and the dependence of the cleaning process on the initial contamination of the wastewater increased. In order to ensure the successful removal of the easily decomposing organic pollutants from the wastewater up to their allowable contamination level, the quantity of the pollutants in the untreated wastewater must not exceed 220 mg O2 LE-1.
Afficher plus [+] Moins [-]The influence of neogene lithology on the Lithuanian river hydrologic regime
2010
Litvinaitis, A., Vilnius Gediminas Technical Univ. (Lithuania) | Saulys, V., Vilnius Gediminas Technical Univ. (Lithuania) | Bagdziunaite-Litvinaitiene, L., Vilnius Gediminas Technical Univ. (Lithuania)
Due to the recently increasing frequency of extreme changes in river runoff regime, scientific literature deals with the characteristics of runoff formation. Works are carried out in analyzing climate changes and a lot of attention falls on land–use structures. Following thorough analysis of the lithological structure of river basins in separate costal zones, this article aims at evaluating river runoff formation characteristics. The basin lithological factor was calculated based on Quaternary map of Lithuania M 1:200000 and Lithuanian river map M 1:50000 using ArcGis software. In order to carry out more thorough analysis of the influence of lithology in given territories, sections of 0–20 m, 50–200 m, 200–500 m, 500–800 m, 800–1000 m and is greater than 1000 m were established, calculating the distance in meters from the riverbank. Eight river basins of typical lithological structure (sandy, loamy, argillaceous) were selected and examined. The period of the years 1960–2007 was analyzed as this period saw the greatest amount of precipitation (up to 33% probability), and relation between the runoff and precipitation was established as well as that with the lithological structure, established following the derivation of a hydromodule.
Afficher plus [+] Moins [-]The maximum runoff changes in Venta near Papile and Krazante near Pluskiai rivers
2010
Bagdziunaite–Litvinaitiene, L., Vilnius Gediminas Technical Univ. (Lithuania) | Vertelkaite, V., Vilnius Gediminas Technical Univ. (Lithuania)
Global warming undoubtedly influences the flow of rivers. It is essential to observe the climate changes, trace, analyse and forecast how they could influence the environment and, especially, how it can influence the flow of rivers. In this article two maximum flows of basins of two different rivers are analyzed: the river Venta (above Papile) and the river Krazante (above Pluskiai) during the period 1968–2008. Climatic parameters, such as the precipitation and the average air temperature, observed in the weather stations of Siauliai and Laukuva, influence the changes in flows the most. The correlation between the precipitation and maximum change of the flow was estimated though it was not strong: the ratio of correlation in the river Venta was 0.66, in the river Krazante the same ratio was 0.72. Significant negative trends of the both analyzed rivers during the spring period and significant negative trends of the river Venta during the period of winter have been established by the use of statistical analysis of the results obtained from a non-parametric Mann-Kendall test and linear regression test. This specific analysis is performed by using TREND programme. The collected data which were obtained to show that the most watery decade of the rivers Venta and Krazante were during the period 1978–1987, which formed 36% flow in the river of Venta and 35% in the river of Krazante for the whole period of forty years.
Afficher plus [+] Moins [-]Guideline for development of landscape spatial composition of the residential areas
2010
Ile, U., Latvia Univ. of Agriculture, Jelgava (Latvia)
The development of the multi-storey residential areas in the Baltic Sea region shows an inequality that changes the spatial environment of the territory. The major part of the city territory is occupied by the multistorey residential area that reveals multiple problems of the spatial environment. Therefore, it is necessary to resolve these problems by building new more multi-functional zones in the multi-storey residential areas that would further ensure the sustainable development of the spatial environment. To find the relevant data and material, a scheme of questions for analysis was developed. The scheme reflects all the necessary aspects for the analysis of the landscape composition in multi-storey residential areas. The analysis from the theoretical aspect with the usage of empirical methods determined the current state of the multi-storey residential areas in the Baltic Sea region. The paper presents the study of historical development and the causes of changes, as well as the current state and potential future development of the landscape composition of the multi-storey residential areas. It also reflects the development framework of the landscape composition. The multi-storey residential area that carries a great load of the multi-functional areas, needs an improvement, a renovation and needs to be reconstructed and developed according to all the mentioned characteristics of the spatial environment.
Afficher plus [+] Moins [-]Landscape classification of the Lielupe River valley - humans' use of river landscape and landscape elements
2010
Purs, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
Civilization has historically flourished around rivers. There exists invisible and visible social activity system in the river landscape. With the world's economical, technological and social development, a focus on meeting human needs is vital. There is a need of a reinterpretation of landscapes' functions and revision of archetypes. The proposed approach is search for design of lifestyle versus design for territory. The research is based on the Lielupe river case study. The aim of the on-going research is search for approach to solve individuals' role of the river landscape. The task of this paper is to identify types of individuals' use of river landscape. Data collection was performed both from individuals' prospectus of use of landscape and from the functional use of river as a landscape object supplementing data both ways. I investigated it by analyzing intuitive images, making of an observation of people's habits, behaviours and occupations, and by cartographic analysis. At this stage of research there were observed seventeen groups of functions in the landscape of the Lielupe river valley, characterized by wide range of actions, described by landscape elements, and organised in social groups. These data are assessed by grading of their influence on landscape and its participants. Sixteen marginal grades were detected. This highlights a high potential for development of river landscape with an individual's participation in it. The further investigation is to develop ergonomic and functional planning principles for each type of interest group to compromise the individuals' needs.
Afficher plus [+] Moins [-]Development of public art in the urban space: expressions and potential
2010
Alle, E., Latvia Univ. of Agriculture, Jelgava (Latvia)
The research deals with public art, and its related discourses. The particular focus of the paper is on investigating how public art can be a resistant or controversial part of the urban space. The first part of the paper describes the historic development of public art through time. Subsequently, the discussion goes on to the main aspects which dominate art in the public, urban space. We focus on the site-specificity realm, sculpture and installation, the role of public art in urban regeneration as well as influences in society. Today, it is argued that public art shifts its focus from object to process, from artist to audience, and that the artwork becomes part of city development policies, approaches to people’s everyday life. Currently the quest of contemporary public art becomes one of the main subjects to explore and find definitions for. The methodology used in this paper is descriptive, based in a historical point of view. The aim of this research is to find out the main development lines of public art, trying to answer questions such as: how is public art expressed in the urban space realm? What is its potential?
Afficher plus [+] Moins [-]Role of web browsing layout engine evaluation in development process of more usable web information system
2010
Vitols, G., Latvia Univ. of Agriculture, Jelgava (Latvia) | Arhipova, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
This paper focuses on evaluation of web browsing layout engines used as a backbone in web browsing software. Study of commonly used web browsers and Web information system developing languages has been performed. The role of web browsing layout engine evaluation in web information system development process is identified as a critical matter for bringing business processes online in a form of usable and accessible information system. By analyzing web browsing layout engines as a tool that renders elements on a particular Web page of web information system, key tendencies and emphasis for web information system developers are revealed and discussed.
Afficher plus [+] Moins [-]Intercultural communicative competence
2010
Araja, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Aizsila, A., University of Latvia, Riga (Latvia)
The aim of the study is to investigate and analyse the Model of Intercultural Communicative Competence in the Primary Schools. The investigation is based on the theoretical approach – scientific literature analysis of Intercultural Communicative Competence is done. According to that the Model of Intercultural Communicative Competence and the Competence assessment in the Primary Schools' Foreign Language (English) Lessons (for students aged 12-14) has been made. The Model of Intercultural Communicative Competence comprises Linguistic competence, Sociolinguistic competence, Discourse competence, and Intercultural competence. The developmental model of intercultural sensitivity consists of Ethnocentric stage (denial, defence, minimization), and Ethnorelative stage (acceptance, adaptation, integration). Intercultural methodology for teaching foreign languages includes Intercultural comparison, Intercultural didactics, and Intercultural Language awareness. Assessment of Intercultural communication competence shows culture understanding: empathy toward other (target) culture, ability to observe and analyse a culture, ability to communicate in the foreign (target) language.
Afficher plus [+] Moins [-]Development of critical thinking for medical students in chemistry course
2010
Kazusa, I., Riga Stradins Univ. (Latvia)
Placing emphasis on high level of responsibility, professionalism and tendency for improvement is expected from medical students. A continuous flow of information puts medical students in front of a choice between the already known and the new. It is therefore necessary to think flexibly and to be ready to verify information and admit mistakes – it is necessary to be able to think critically. While studying chemistry in Riga Stadiņš University, students have an opportunity to use critical thinking methods for certain purposes – investigation of laws of nature. Development of critical thinking therefore is an integral component rather than the goal of medical education. A complex education method with linked didactic methods was developed – the goals are development of critical thinking during practical work, development of study process organization skills, and critical analysis of information, situation modelling, self-assessment and self-dependence. In order for used didactic methods to work, levels of student qualification were taken in consideration and students were offered an opportunity to evaluate their work themselves. By adapting different forms of studying to each topic of theoretic course and practical work, it was possible to find the most effective as proven by student questionnaires. As research shows, the most effective didactic methods are: 1) special assignments where students have to verify given facts; 2) situations where students are directed towards intensified analysis of conditions of assignment; 3) mastering of science-based research principles which include promotion of theories, practical testing, result analysis, and conclusion drawing.
Afficher plus [+] Moins [-]Experimental investigation of solar energy collector on production capacity of hot water
2010
Jesko, Z., Latvia Univ. of Agriculture, Jelgava (Latvia) | Ziemelis, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
Pollution of atmosphere and decrease of fossil fuels stimulates people to search for an alternative energy sources for production of energy, both electrical and heat. In Latvia it is possible to use almost all alternative energy sources for production of energy, including solar energy that becomes more relevant year by year. Solar radiation in direct way makes no hazardous, but, as the intensity of solar radiation in geographical location of Latvia is comparatively low, the utilization of it demands relatively expensive equipment. Production of energy from other sources of energy also demands certain investments as well as the purchase of fuel, maintenance of equipment and presence of different manipulators. In practice several types of solar collector constructions with efficiency from 30 up to 75% exist and expenses vary in the wide range. The average number of sunshine hours in Latvia is about 1800 hours yearly. Nevertheless solar collectors for water heating in Latvia are used. Mostly flat-plate collectors are used whose efficiency often is not sufficient and water has to be additionally warmed-up. The aim of our investigation is to study operation of evacuated tube collector in conditions characteristic to Latvia. It is stated that it is feasible to use evacuated tube collector for water heating in Latvia, especially from March till October. During winter period solar collector can be used as additional energy source for water heating.
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