The interaction between short fibres and concrete in the post-cracking phase influences crack spacing and width in the composite. In order to perform analysis of deformation of a composite and the fibre displacement at the crack, single fibre was examined. A two-fibre model considering the distribution of fibre length and incomplete bonding was developed. Numerical analysis reveals that two-fibre model analysis is believed to be more accurate than that obtained from the single-fibre analysis. Comparing the solution of the single-fibre and two-fibre system shows that the latter gives a greater fibre displacement at the crack. The study was performed in the Department of Structural Engineering, year 2009/2010.

Informatics is profoundly reshaping social relations and changing pupils’ education. A goal was set to offer the pupils an integrated informatics learning content, orientated to develop an emotionally and intellectually equilibrated and harmonic personality. The aim of the paper is to characterize the integration in the content of the subject of informatics and research the realisation of integrated learning material in educational practice. Subjects in the school curricula provide concrete guidelines on knowledge, skills and attitudes that should be taught and what goals and purposes their education program follows. To establish the understanding of pupils on development of taste in integrated informatics subject, an educational experimentation was conducted. The data are obtained by using a pretest-post-test design and analysis of teaching-learning informatics in classroom. Pupils at Lielvarde secondary school were asked to involve for learning a new integrated informatics material for developing their understanding of taste. The method of analysis of aesthetic and pedagogical literature and data processing and analysis by Wilcoxon signed-rank Test and Chi-square test are used. Pupils undertook independent practical tasks at the computer with the aim of developing their knowledge and cognitive skills (understanding, selection, reflection). Learning integrated informatics material is a pedagogical condition for fostering the development of pupils’ understanding of taste. Learning integrated informatics material executed diverse practical tasks with choice of color match, ethnographic characters and making a portfolio which enriched pupils' experience of taste and effectuated as acquisition of their cognitive skills.

The aim of the study: to analyse the principle of exemplarity, comprehend its features and their usage in university exact courses learning practice. The principle of exemplarity is a means of arranging the geodesy study course programme according to the most essential notions of the course and students abilities and knowledge level at Latvia University of Agriculture. It is one of the cognitive learning didactical principles proponed by the German scientist Martin Wagenschein and recognised in a teaching/learning process particularly in natural sciences. The origination of the principle of exemplarity, its relevant features and experience of other countries are analysed in the article. The following notions of the principle are analysed in the article: coping with information quantity, comprehension of a course entity and epistemology, interdisciplinarity; usage of exemplar as a feature of entity criterion in obtaining particular knowledge and skills; traits of Socratic dialogue. The principle of exemplarity is combined with problem-based learning, project method and student-centred approach and is used and discussed particularly in Germany and Denmark. The principle features and the ideas of its usage are being assessed, worked in and implemented in the geodesy study course programme for the land survey speciality first year students. The programme is revised thematically determining the focal themes (exemplars) in laboratory works via which the principle of exemplarity can be the means of obtaining the course of geodesy successfully.

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.

Grain after enzymatic treatment, which is a starch-containing raw material, is used for ethanol production. Bioethanol production in Latvia began in 2006. Extraction of biofuels is a clean process, because the byproduct is used in various sectors of the economy. The bioethanol in Latvia was derived primarily from winter wheat, winter rye, and winter triticale. The objective of the research is to determine the different nitrogen fertiliser rates required for winter cereal crop yields and bioethanol outcome. The trials were carried out from 2005 to 2008 in Agricultural Science Centre of Latgale (Latvia). The method (ethanol outcome) is based on fermentation of saccharified cereal samples by yeast Saccharomyces cerevisiae followed by the calculation of ethanol outcome and speed of fermentation. The highest starch content was in winter wheat and winter triticale grain, but the lowest - in winter rye grains. A close negative correlation (p is less than 0.05) was found for winter triticale and winter wheat between the ethanol outcome and thousand grain weight. Production of bioethanol from rye starch content is used with full utilisation of grain. The winter wheat has the largest ethanol outcome from one hectare.

Precocity of fruit plants enables early obtaining of yield and income. But precocity can be influenced by drought. In some cases precocity is related to insufficient growth and insufficient yield in the succeeding years. The precocity of sour cherries was investigated in the trial established at the Latvia State Institute of Fruit Growing. Soil moisture treatments - woodchip mulch and drip irrigation as well as cultivars ‘Bulatnikovskaya’, ‘Desertnaya Morozovoi’, ‘Latvijas Zemais’, ‘Orlica’, ‘Shokoladnica’, ‘Tamaris’, and ‘Zentenes’ were used as trial factors. The flowering and yielding was observed in 2008 and 2009. Flowering, fruit set, fruit mass, and yield were characterized in order to evaluate precocity of cherries in different soil moisture treatment variants. The use of drip irrigation did not influence the yield of sour cherries, but the use of woodchip mulch decreased the yield in the third growing year. The cultivar ‘Tamaris’ was the most precocious, and the cultivar ‘Bulatnikovskaya’ was the most productive.

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.

This paper presents results of pressure oscillation investigation in hydraulic hitch-system of a tractor Claas Ares ATX 557 during the motion during artificial roughness road test. During experiments oscillation at different driving speed, tyre pressure and hitch-system oscillation damping (turned on/off) were investigated. Tractor hydraulic hitch-system was equipped with a pressure sensor Wika Transmitter ECO-1 and data processing software PicoLog. Results of experiments present maximum pressure peak of 210 bar in the tractor hydraulic system when hydraulic hitch-system oscillation damping system at driving speed 8 km·hE-1 is not used and system pressure peak reduces to value of 180 bar if the hydraulic hitch-system oscillation damping is used.

Barley is a key ingredient in beer production. The aim of the current research was to study the dynamics of vitamin C and vitamin E in flaky and hull-less barley grains during steeping, germinating, and kilning. The research was accomplished on hull-less barley (two lines – '3528' and '3537') and flaky barley selected in Latvia in 2009 with a germination capacity above 95%. The grains were steeped, germinated and kilned using traditional malt production technology. During research the vitamin content was analysed using standard methods: vitamin C by EN 14130:2003, and vitamin E by AOAC 971.30. The content of vitamin C increased during steeping in flaky barley grains till 0.23 mg 100 gE-1, but in hull-less barley grains: line '3537' till 0.47 mg 100 gE-1, and line '3528' till 0.30 mg 100 gE-1. During germination vitamin C content in flaky barley increased by 68%, in hull-less barley: line '3528' – by 82%, and line '3537' – by 57%. The content of vitamin C in the analysed malt samples was 0.35-0.38 mg 100 gE-1. The content of vitamin E in all barley samples was similar after grain steeping. The content of vitamin E was 3.9 times higher in flaky barley, but in hull-less barley lines: '3528' – 4.1, and '3537' – 4.5 times higher compared with its initial content after germination. After grain kilning, the content of vitamin E decreased in all barley grain samples. The results show that using some cultivars of hull-less barley for malt production, it is possible to obtain a higher content of vitamins C and E in the end-product.

Jerusalem artichoke powder (JAP) from Jerusalem artichoke (Helianthus tuberous L.) roots is a nutritive valuable product that can be used for a healthy product development. The influence of JAP on the quality and degree of liking of cakes was investigated. Sensory evaluation of cakes was realized in two stages: the first - to define the quality attributes of the cakes with JAP from the point of view of the experts, the second – to find out the consumers' views on the cakes, whose quality has been improved in accordance with the recommendations of the experts. As a control sample, the classic home cake was evaluated. Control sample was compared with the cakes, where the amount of wheat flour prescribed by recipe was partly substituted with JAP at different concentrations. Experts evaluated cakes and defined the highest acceptable concentrations of JAP in cakes. For the consumers it was offered to assess the cakes with JAP at concentration 30% and with different taste and aroma enhancers. Cakes with 30% of JAP additive were the most favoured by the sensory properties: aroma, texture, softness elasticity, porosity and softness, surface crust, appearance, colour, shape, and size. Results of analysis of variance showed that there no significant differences in the degree of liking between the cakes with JAP and the cakes with taste and aroma enhancer additives (p is greater than 0.05). There had been performed hardness analysis and colour measurement for cakes with JAP. The observed results declare high influence of aroma and taste enhancer on cakes structure and colour.