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.

This article presents the results of studies of the chemical composition of the fish meat while using as a feed additive zeolite of Chankanay origin. The research was conducted during 2011-2013 at the Department of Veterinary-sanitary examination and hygiene of the Kazakh National Agrarian University and at the laboratory of JSC ‘Kazakh Academy of Nutrition’ LTD ‘NUTRITEST’. The material of study was the zeolitic tuff of Chankanay deposit (Almaty region) and two-year trout Oncorhynchus mykiss. For the research we used feed by recipes of GosNIORH - 12-80. The chemical composition of fish meat was determined by a set of methods: moisture by drying at 105 °C, fats by Soxhlet, total protein by modified Kjeldahl method (ISO 937:1974), and minerals by incineration in a muffle furnace. Calorie content of meat was determined by Alexandrov’s formula: X = C - (F+A) ´ 4.1 + F ´ 9.3. Fatty acid composition of fish meat was determined by gas-liquid chromatography. Thus, the results are the indirect evidence that zeolites added to primary diet for growing fish, do not adversely impact proteolytic enzyme systems of fish, that is, have no negative effect on fish organism.

Invention of light weight cellular wood material (CWM) with a trade mark of Dendrolight is one of the most important innovations in wood industry of the last decade. Currently CWM has been used as core material for sandwichpanels. These three layer panels are used in furniture industry and have wide non-structural applications. The aim of the research was to define the thermal properties of CWM and evaluate various wall envelopes where solid wood cellular material is used. There were 4 specimens of cellular wood material manufactured with nominal dimensions thickness 120 mm, length and with 600 mm to determine thermal conductivity and thermal transmittance according to standard EN 12667:2002. The specimens were manufactured of four layer 112 mm thick Scots pine (Pinus sylvestris L.) CWM double faced with 4 mm thick high-density fiberboard (HDF). Adhesive used in the bonding process was polivinilacetate Cascol 3353. Each direction (parallel, perpendicular) was represented by two specimens. Common procedure to evaluate the energy efficiency of building envelope is to calculate thermal transmittance in static conditions. The influence of the cellular material orientation to its thermal properties was investigated. Coefficient of thermal conductivity was determined for both material directions of CWM (l0 =0.0977 W∙m-1∙K-1 l90=0.148 W∙m-1∙K-1), combining the test method of EN 12667:2002 and calculation method of standard EN 6946:2008. To calculate thermal transmittance of various wall envelopes calculation software in JavaScript environment was created. Various compositions of external walls were assessed, thermal transmittance of these structures were calculated according to standard EN 6946:2008.

Economic importance of Silver birch in Latvia has been increasing in last decade, triggering scientific research, dedicated to improvement of this species, including tree breeding. Bulk of progeny trials will reach the evaluation time in next few years; therefore, decisions for further tree breeding activities have to be made. The aim of our study is to evaluate profitability of silver birch breeding, based on current situation in the year 2010 and circumstances in Latvia and assess the factors that might notably influence the result. Analysis considers all available breeding material and links between tree breeding, seed orchards and end product – forest stand, regenerated with improved plants in order to evaluate profitability of different alternatives based on differential approach. Results reveal that differential benefits from forest regeneration with selected birch material in comparison to natural regeneration, in areas with highest site indexes (Ia-II) with 3% interest rate and at least part of the stands managed in order to maximize yield of large diameter trees at age of final felling, are positive. The highest profitability can be reached if selection of best individuals is done based on clonal testing, genetic gain is maximized and combined with proper silvicultural praxis and annual planting area (utilization of seeds from selected trees) are maximized.

Avian metapneumovirus (AMPV), formerly known as avian pneumovirus (APV) is epizootic agent of turkey rhinotracheitis (TRT) and swollen head syndrome (SHS) in turkeys and chickens. The infection primarily affects the upper respiratory tract of young birds (broilers), while also decreases egg production of adult hens. Thus, the development of infection in susceptible birds of any age can cause serious economic losses. The purpose of this study is to test serums from broilers and hens for the presence of antibodies against the avian metapneumovirus. In this series of studies 317 serum samples taken from one 1 day to 75 weeks old birds were tested. Thus, on the basis of serological tests of blood serum and of chicken flocks and broilers, we had a preliminary diagnosis on the presence of avian metapneumovirus infection. Serological studies of unvaccinated against avian metapneumovirus infection bird flocks using the ELISA method showed antibody titers on average at 22 859 ± 4133. Avian metapneumovirus infection in birds was accompanied by a decrease in egg production of chicken flocks by 8.0 - 12.8%.

This article summarizes data of determining a therapeutic dose of a new immunocorrecting drug, dermatocytoglobulin, developed by the authors of this study. It has been established that this drug has a therapeutic immunocorrecting effect on allergic dermatitis. Subjects of the study cattle, horses, of Raimbek – Commercial Diary Farm, 56 dogs and 35 cats admitted to a veterinary clinic. It has been established that administration of dermatocytoglobulin in trial groups reduces autoantibody titers until their elimination on the 12th day, dose of 0.2 cm3 per 10 kg while autoantibody titers in control groups were identified on the 30th day.

The growing popularity of wooden panels renders this market segment increasingly competitive. The article describes a new type of fibre boards e.g. the furniture production, developed in cooperation with ATB (Leibniz-Institute for Agricultural Engineering Potsdam-Bornim) by using a new method of raw material preparation and specific production technologies of ATB. The main raw material is preserved hemp (Cannabis sativa) stalks. The samples are made of raw materials with different wet-preservation time and varying types of binder. For the first time there is used main raw material with short time wet-preservation. Samples that are 8 mm thick correspond to a medium-density fibreboard and that are 16mm thick correspond to a low-density fibreboard, fitting in its mechanical properties to standard BS EN622. On ATB’s experimental processing line 1,200x800x8 mm and 1,200x800x16 mm size board samples are produced and the tests are performed to determine such parameters as bending strength, thickness swelling and thermal conductivity according to EU standard methods.

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.

The added value of woodworks is determined by the surface quality because it is the first one seen and evaluated by the client. In the production process it is quite problematic to evaluate woodworks surface quality because of large production capacity, and the processed material can be instrumentally tested with a definite time shift. In production most frequently the surface quality is evaluated visually, which is not quite precise. At the same time during the mechanical processing of wood noise is caused by cutting tools as they gradually wear out. The same reasons influence the increase of noise and the quality of woodwork surface. The essence of the problem is to analyze the registered increase of the noise level at a definite workplace and simultaneously follow the surface quality of the processed material – roughness and wear-out of the cutting instrument. The objective of the paper is to research the method of the noise level data collecting and application in order to evaluate wooden product surface quality during wood processing by milling machines. It would provide an opportunity to update the management processes of massive woodworks, supervise the surface quality of woodworks, reduce costs and increase the added value.

The Duration of Load (DOL) effect is the combined influence of the mechanical loading history and climatic history on the strength of materials. DOL effect is one of the most important characteristics of wood and wood-based materials. The material degradation or damage induces strength reductions. Creep is one of the most important effects of DOL. Creep is a phenomenon that negatively affects functional compliance, behaviour and strength of timber structures in extended years of exploitation. The creep phenomenon is affected by surrounding temperature, relative humidity, timber moisture content and other factors. The study aimed to establish a correct factor system for accurate prediction of long-term deformations of timber structures that is corresponding to environmental conditions and timber properties in the region of Latvia. The experimental research was made in Jelgava, Latvia, and represents timber beam four-point long-term loading in bending with variable cross section height-span length ratio under uncontrolled climatic conditions. There were 12 timber beams with two different span lengths – 1.32 m and 1.50 m used. The timber beam cross section dimensions: height – 60 mm, width – 30 mm. The timber beams were not dried and the moisture content at the start of the experiment varied from 19% to 33%. The applied load values – 0.40 kN and 0.31 kN. Moisture content fluctuations and negative air temperature accelerated creep development and intensity. Prediction of final long-term deformations should rate not only the type of timber material and service class but the strength class, too.