As worldwide trends are changing gradually and sustainable resources economy and reduction of hazardous emissions are coming to the forefront, several industry sectors are forced to revalue their resource consumption. The main emphasis is currently placed on the recycling of by-products. One of the methods, definitely, includes burning of by-products to generate power, however it is not always the most efficient one. By-products must be used in the manner that ensures that they provide high added value for the operation of the company and are environmentally friendly. This research focuses on the use of the by-products of birch (Betula) veneer manufacturing, in order to obtain thermal insulation material. The following characteristics of the wood fibre insulation material were determined: thermal conductivity, water absorption, vapour permeability, and prototype reaction to fire. The characteristics of the obtained wood fibre thermal insulation material: thermal conductivity 0.038 W•mE-1•kE-1; water absorption 12 kg•mE-2; the conformity of the material even to D fire reaction class was not determined. The principal conclusion: the wood fibre thermal insulation material conforms to the requirements set for thermal insulation materials.

Apples are the most popular and common fruits in Latvia. Storage technology is crucial to preserve fruit quality as long as possible. Choosing the appropriate gas content of the storage environment can prolong storage life two to three times for apples. The aim of the research was to compare six different type of apple grown in Latvia, which was stored in diverse conditions. All experiments were performed at Latvia State Institute of Fruit-Growing through 2011 – 2012. For fruits before storage, 1-methylcyclopropene (1-MCP), which blocks the emission of ethylene, was used. Apples were stored in a cooler and in ULO type plastic bags in a modified environment with two different gas contents. The temperature of the environment was +2 ±1 °C with 90% relative humidity. Changes in physicochemical (soluble solids, total acids and flesh density) indexes were examined before and during the storage. The results showed 1-MCP has a positive effect on quality preservation of fruit. Fruits stored in ULO type plastic bags (gas content: 1.5% O2 and 2.5% CO2) had the best results in preservation of physico-chemical indexes. Examination of results revealed that physico-chemical indexes changed the most in samples stored in the cooler.

The objective of this study is to evaluate the performance of models developed by Repola (2006) to estimate the vertical changes of the basic density of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies [L.] Karst), and birch spp. (mainly Betula pendula Roth) stemwood in the forests of Latvia and to develop a model for the estimation of average knot-free stem density with bark (SD) using diameter at breast height as an independent variable. The study material comprised a total of 81 spruce, 102 pine, and 105 birch stems representing a wide range of tree growing conditions in Latvia and covering all age classes. The knot-free stemwood density (SWD) of pine and birch demonstrate strong vertical dependence along the stem, while for spruce the variation pattern was less pronounced and seemed to be nearly constant along the stem. The SWD estimated by Repola’s models was 4.3% lower for spruce, but 3.4% higher for pine and 2.2% for birch comparing to average values obtained in this study. Sigmoidal regression equations constructed in our study explained 67%, 27% and 54% of variations for predicting SD for pine, spruce and birch, respectively. Birch stemwood has a highest basic SWD – 470 kg mE-3, followed by pine – 397 kg mE-3 and spruce – 385 kg mE-3. According to our results, the birch bark turned to be denser than the birch stemwood, being vice versa for the studied coniferous species.

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.

The aim of this study was to detect radiodensity of a medial coronoid process of elbow joints with a medial coronoid disease and normal elbow joints in dogs. The study includes 91 large and giant breed dogs at the age from 6 to 30 months. Medial coronoid disease was diagnosed in 65 dogs and 26 dogs had normal elbow joints. Computed tomography was performed with Philips MX – 16 CT scanner and imaging data analysis performed using Horos v.2.2.0 software. CT technical data included 140 kVp, 250 mAs, 1 second rotation time and 0.75 slice thickness. The density of a medial coronoid process (MCP) was measured by two unrelated measurement methods. The study describes Hounsfield unit values in different areas of MCP in normal elbow joints and in medial coronoid disease affected joints. In 91.8% cases, MCP subchondral sclerosis observed with MCP fragmentation or fissure. We conclude that both bone density measurement methods are suitable for veterinary diagnostic imaging and can be used to evaluate canine elbow joints.

Vegetable oils are essential providers of energy to a human body; they play important role as a foodstuff. During processing and storage of vegetable oils, they may undergo molecular changes adverse to the human organism affecting the quality of the oils. The content of fatty acids of fresh rapeseed, linseed and hemp oils and of the mixture of rapeseed (800 g kgE-1) and linseed (200 g kgE-1) oils was determined by the method of gas chromatography (GH). Alpha - , delta - and gamma - tocopherols were analyzed in the vegetable oils by the methods of the highly effective liquid chromatography (HPLC). The hemp oils contain the indispensable polyunsaturated fat acids: linoleic acid - 53.0%, and linolenic acid - 23.2%. Such proportion of the fatty acids (3:1) is considered optimal in the nutrition. When using both hot and cold pressure technology for the obtaining of oil, it is possible that the polycyclical aromatic hydrocarbon - Benzo[a]pyrene - may be created and influenced the quality of the oil. The environment also affects the content of the lead in the oils. The density of the various vegetable oils at the temperature of 20 +- deg C proved to be within the limits of 0.917 and 0.942 kg dmE-3.