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Modelling of unidirectional short-fibre reinforced concrete
2010
Skadins, U., Latvia Univ. of Agriculture, Jelgava (Latvia) | Brauns, J., Latvia Univ. of Agriculture, Jelgava (Latvia)
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.
Afficher plus [+] Moins [-]Thermal conductivity of experimental wall constructions of renewable insulating materials
2019
Visockis, E., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Pleiksnis, S., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Preikss, I., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Skujans, J., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Gross, U., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia)
Global scale environmental problems and economic issues are the main aspects what point out exigency to do research in the construction of renewable building materials. Renewable building materials are those materials that can be regenerated quickly enough and in theory, their production could be carbon-neutral. In order to evaluate the thermal efficiency of renewable materials in the framework systems of building envelope structures, test samples were made with the filling of renewable materials. The aim of the work is to find out the thermal conductivity coefficient of these natural composites and to compare them. Different size test samples were created for determination of thermal conductivity coefficient: 1.type as reference value: (width x height x depth) 290 x 290 x 30 mm; 2.type as experimental construction value (imitation of real wall construction): (width x height x depth) 980 x 980 x (165; 250; 345) mm. In this research as renewable insulating materials were used: maple leaves, legume (Galega orientalis), the composition of hemp shives (Bialobrzeskie) and sapropel with lime. A renewable insulating materials (also known as eco-thermal insulating) as alternative building materials discussed in this research work meets the requirements of the normative documents of the Republic of Latvia on sustainable construction principles. The analysis of results indicates significant difference among investigated materials – 0.040 W mE−1KE−1 lowest obtained value of thermal conductivity coefficient.
Afficher plus [+] Moins [-]Temperature distribution in wood floorings exposed to fire
2007
Buksans, E., Latvia Univ. of Agriculture, Jelgava (Latvia)
Wood construction elements are widely used in buildings and they can be used in construction elements such as roofs, floorings, windows and doors. As wood is combustible material, there are lot of fire regulations that should be fulfilled at the design stage of any building project. In Latvia, as in some other countries usage of wood in building constructions is limited. Wood materials are an ecologically friendly material and a renewable resource, and its usage should be promoted. The paper presents an overview of heat distribution in wood floorings exposed to standard heat fluxes which is different compared to wood members exposed to high heat radiation. Fire spread and self-ignition investigation on wood floorings is carried out in this research. The results show different kinds of the temperature distribution in the cross section of the wood member cross section depending on heat radiation and location of the temperature measurement point. Temperature distributions in wood during fire can be completely different in dependence on heat radiation and cross section of the wood member. The wood materials in floorings do not reach the self-ignition temperature during standard heat radiation.
Afficher plus [+] Moins [-][Analysis of export and import of the most important building materials (1995-1999)]
2001
Gusta, S. (Riga Technical Univ. (Latvia). Production and Entrepreneurship Inst.)
The article deals with the current situation in production of building materials and foreign trade in Latvia. Export and import of building materials are one of the most important factors influencing the production of building materials. The report analyses import and export development trends within two sections of the harmonized system: wood and articles of wood; the articles of stone, plaster, glassware and ceramics.
Afficher plus [+] Moins [-]Exercise yards and feedlots and their impact on the environment
2002
Puumala, M.(MTT Agrifood Research Finland, Vihti (Finland). Agricultural Engineering Research) | Uusi-Kaemppae, J. | Nykaenen, A. | Heinonen-Tanski, H.
Requirements concerning the welfare of production animals and the low profitability of beef cattle breeding have brought exercise yards and feedlots to Finnish farms. Depending on the use of the yard, there are different aspects that have to be taken into consideration. The structure of the yard, the surface material and the space allowance are important from the point of view of both animal welfare and environmental impact. Two exercise yards have been designed, constructed and monitored, together with two feedlot areas. Samples of runoff water, gravity water, subsoil and topsoil have been taken. Their nutrient concentrations and hygienic quality have been analysed. The behaviour of animals has been observed.
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