The objective of this study was to observe and evaluate the ability of innovative vascular prosthesis, made in Riga Technical University (RTU), to incorporate in a canine model. The research has been performed in Veterinary Medicine Faculty of Latvia University of Agriculture since July 19. 2011. The research was approved by the Food and Veterinary Service of the Republic of Latvia. The research is realized within the framework of European Social Fund co-financed project ‘Establishment of interdisciplinary research groups for new functional properties of smart textiles development and integrating in innovative products’ (ESF No 2009/0198/1DP/1.1.1.2.0./09/APIA/VIAA/148). RTU produced aortic grafts 5-8 mm in diameter and 8 mm to 18 mm long were implanted retroperitoneal in 9 female, 1-3 years old Beagle dogs. Once before and regularly after the surgery, abdominal aortic and vascular graft diameter was measured in cross sections. Blood pressure was measured before and regularly after the procedure. Results show no significant differences in aortic and graft diameter before and 12 months after the operation and there are no significant differences in systolic and diastolic blood pressure before and 6 months after the aortic surgery at a significance level α 0.05. The study shows that the innovative aortic prostheses do not change in diameter and abdominal aorta transplantation surgery does not cause significant variations in blood pressure. Study is continued to find out later reactions to synthetic vascular graft.

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.

The paper contains description of the working principles and evaluation of the operational parameters of the commercially available fuel conversion adapter, intended to adapt gasoline fuelled spark ignition (SI) engine for use of high ethanol content blended fuel, known as E85. Commercially available gasoline and E85 fuel were used as test fuels. Production automobile, equipped with 1.8 litre 4 cylinder SI port fuel injection (PFI) engine was tested on the roll-type eddy-current chassis dynamometer in wide open throttle (WOT) constant speed mode. High precision fuel consumption measurement system AVL KMA Mobile was used. Engine operating parameters, used for evaluation of the efficiency of the fuel conversion adapter was engine torque (T), engine brake power (Pb ), air/fuel equivalence ratio (λ), specific fuel consumption (SFC) and engine thermal efficiency (ηt ). Analysis of engine operational parameters showed successful operation of fuel conversion adapter with E85 fuel, resulting in increase of engine peak torque by 4.4%, increase of energy efficiency in whole tested engine speed range up to 6.1% but increase of specific fuel consumption by approximately 22%, when compared with the gasoline use.

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.

This research deals with tendencies of growth of Norway spruce Picea abies (L.) Karst. during last 50 years (1960 – 2010) in eastern part of Latvia emphasizing trendal specificity of active periods during the first (t1: 1960-1985) and the second (t2: 1986-2010) time interval. There have been 150 superior stand trees bored in six mixed pine-spruce Pinus sylvestris L. – Picea abies (L.) H.Karst. stands. An active period of factor’s impact is the time span when some meteorological factor (decade average, minimal or maximal temperature and sum of decade precipitation) influences an increase of annual ring width significantly. Comparing average temperatures from two weather stations included in this research the difference between interval t1 and t2 is approximately 1 °C. Active periods of temperature impact on growth of Norway spruce in eastern part of Latvia during last decades have changed not only their location but also an impact direction from positive to negative. Minimal and maximal decade temperatures are those mostly determinating the radial growth of Norway spruce in the eastern part of Latvia. Interval t2 is quite rich in active periods both from minimal and maximal decade temperature. Research results prove hypothesis about trendal shift of meteorological factors’ impact active periods due to climate change. An increase in decade precipitation level in winter caused annual ring growth positively both in the interval t1 as well as in t2.

Willow species are nowadays extensively studied. Species are being investigated to evaluate their use and role in various sectors of national economy. The use of willows in short rotation coppice (SRC) for biomass and energy production has a priority in the European Union policy. There are many countries that have grants and financial aid system for so-called ‘green energy’ production. Willow species also have other economically and ecologically important features: resistance to contaminants, strong root system, high tannin contents, decorative, etc. Willow SRC systems are used for phytoremediation and in wastewater purification, in combination with biomass production. There are several countries of Eastern Europe researching adequacy of the willow SRC for the farmland contaminated by radionuclides segregated from the Chernobyl nuclear power plant disaster. Willows are used for quarry restoration, water sludge treatment, erosion control etc, but the most important field at the moment is the biomass production.

The study represents results of theoretical evaluation of forest biomass available for solid biofuel production in pre-commercial thinning in Latvia. The study is based on the National forest inventory (NFI) data; calculations are done for each NFI plot separately. The calculation is done in three steps – selection of the NFI sample plots, which fulfils criteria for the pre-commercial thinning, development of the diameter distribution table, setting the criteria of the thinning intensity, calculation of extractable biomass. Thinning from below (removal of the smallest trees) is considered in calculation. Two types of biomass are accounted – full tree (aboveground biomass) and stem-wood (stem biomass). The study demonstrates that pre-commercial thinning could become an important source of forest biomass in Latvia (15400 GWh of primary energy according to current situation in forests); however, dimensions of trees and harvesting conditions might be challenging for production. The most of the potential biofuel resources are located in stands with average tree higher than 8 m; therefore, it is reasonably to develop and introduce technologies applicable for production of partially delimbed trees.

Machining of wood of soft deciduous trees is currently based on the knowledge about cutting of wood of hard deciduous and coniferous trees and has not developed a comprehensive research methodology of cutting processes. Therefore, the objective of the study is a development of methodology for longitudinal sawing with circular saw and straight milling that would be utilized with a purpose of acquiring further knowledge on wood cutting and the improvement of cutting tool designs. Sub-objective of the study is determination of duration of cutter’s wear periods when using developed methodology. For the purpose of solving problems regarding cutting process of soft deciduous wood, the optimization of cutting tools and cutting modes were carried out in conditions that comply with the tendencies of the practise. The cutting process was carried out by a computer numerical control machine and the data acquisition by electronic measuring instruments. Aspen (Populus tremula L.) wood was used for wood samples. The methodology was developed for sawing, which complements the authors previously described methodology of the milling process investigations. Initially, only the results of periods of cutter wear and cutting velocity effects on these periods when milling process is used were obtained. It was concluded that the methodology can be used for further investigations and the critical wear period begins two times later when cutting velocity increases twice.

Heavy metals are worldwide spread pollutants in soils of functioning as well as abandoned industrial territories, landfills, military areas with its historical contamination, and other sites contaminated by industrial activities. Development of soil and groundwater remediation technologies is a matter of great importance to diminish the hazardous impact of pollution to humans and environment. Sustainable solution can be found for remediation of industrial areas using the stabilization/solidification (S/S) technology, which refers to binding of waste contaminants to a more chemically stable form. Geotechnical properties of soil treated with Portland cement (PC) can be improved when municipal solid waste incineration (MSWI) ash is used as the combined additive. Ash is composed mainly of metals, so environmental impact must be evaluated if it is used as amendment in the cement industry. The use of MSWI ash in stabilization of contaminated soils would be useful for the sustainable environmental management in two ways: S/S contaminated soil gains better geotechnical stability and waste incineration industry gets rid of the ash with high metal content. The aim of research is to provide pilot batch experimental results for leaching of heavy metal compounds when S/S technology is used for contaminated soils using PC and MSWI bottom ash additives. Mineral soils were spiked with copper, PC and MSWI were added in known proportions and leaching tests applied. Main results show that PC addition allows to chemically stabilizing soil; thus, heavy metals are not leached out from combined mass of spiked soil and MSWI bottom ash.

There are about 3,000-4,000 heavy metal contaminated sites across Lithuania. According to Lithuanian legal framework, the only way to manage this pollution is ex-situ cleaning which requires excavation, transporting, storage place and later monitoring. This indicates the urgent need of innovative technologies that would be not only costeffective but also environmentally friendly and have a public acceptance. Such technologies are natural and chemically enhanced phytoextractions. Both technologies incorporate plants that can accumulate excessive amounts of heavy metals. During continuous phytoextraction plants accumulate heavy metals throughout all vegetation period and are harvested together with heavy metals when desired biomass is gained. At chemically assisted phytoextraction metal binding chelates are added to increase heavy metal uptake by plants. Since phytoextraction is considered as promising green technology, many efforts are laid to find the most suitable hyperaccumulator plants as well as ecologically safe chelating agents. This paper intends to overview latest researches done at phytoextraction field and look over this kind of remediation possibilities in Lithuania.