Уточнить поиск
Результаты 351-360 из 2,185
Role of web browsing layout engine evaluation in development process of more usable web information system Полный текст
2010
Vitols, G., Latvia Univ. of Agriculture, Jelgava (Latvia) | Arhipova, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
This paper focuses on evaluation of web browsing layout engines used as a backbone in web browsing software. Study of commonly used web browsers and Web information system developing languages has been performed. The role of web browsing layout engine evaluation in web information system development process is identified as a critical matter for bringing business processes online in a form of usable and accessible information system. By analyzing web browsing layout engines as a tool that renders elements on a particular Web page of web information system, key tendencies and emphasis for web information system developers are revealed and discussed.
Показать больше [+] Меньше [-][Implementation of Moodle in the information technology system architecture of Latvia University of Agriculture] Полный текст
2010
Paulins, N., Latvia Univ. of Agriculture, Jelgava (Latvia)
One of key elements when implementing e-learning system is integration in already existing system. System implementation begins with a planning process and ends with installation and maintenance. First of all, it is necessary to determine project team and set responsibilities, collect all information about current situation and possible changes. Latvia University of Agriculture has just started to plan implementation of Moodle system, as its e-learning environment. This article attempts to provide answers on some implementation questions during the system development lifecycle process.
Показать больше [+] Меньше [-]Traits influencing spring barley competitiveness against weeds under organic and conventional conditions Полный текст
2010
Kokare, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Legzdina, L., State Priekuli Inst. of Field Crops Breeding, Cesis reg. (Latvia)
The aim of studies was to identify how different morphological and biological characteristics influence spring barley (Hordeum vulgare L.) competitiveness against weeds in various organic and conventional farming locations. Do those traits have an influence on the yield and in which growing conditions the selection of genotypes for organic farming should be done? The plant traits related to competitiveness against weeds at the beginning of the vegetation period are important in breeding for organic agriculture. Ten different varieties were included in trials for three years in two organic and two conventional environments. The included varieties were divided in four groups with respect to time of release and adaptation to growing environments: old extensive varieties and landraces for low input agriculture, medium old varieties with good adaptation to unfavourable conditions, modern varieties for low input, and modern varieties for high input conditions. Results showed that such traits as productive tillering ability, development speed and plant height at the beginning of stem elongation stage provide good soil shading. The most of traits were negatively related to the grain yield. Selection of genotypes for traits which influence spring barley competitiveness against weeds, such as a growth habit in the tillering stage, development speed in tillering stage, plant height at the beginning of stem elongation, length of flag leaf and the width of flag leaf, and the plant height before harvest, may take place in conventional conditions as well as in organic conditions.
Показать больше [+] Меньше [-]Effect of different plant production methods on yield and quality of winter wheat 'Portal' in 2009 Полный текст
2010
Tein, B., Estonian Univ. of Life Sciences, Tartu (Estonia) | Eremeev, V., Estonian Univ. of Life Sciences, Tartu (Estonia) | Keres, I., Estonian Univ. of Life Sciences, Tartu (Estonia) | Selge, A., Estonian Univ. of Life Sciences, Tartu (Estonia) | Luik, A., Estonian Univ. of Life Sciences, Tartu (Estonia)
The yield and quality (volume weight, 1000 kernel weight, protein content, falling number, gluten content, gluten index, gluten content in dry matter) of winter wheat was studied in variety 'Portal'. The wheat was part of the five-year crop rotation experiment where red clover (Trifolium pratense L.), winter wheat (Triticum aestivum L.), peas (Pisum sativum L.), potato (Solanum tuberosum L.) and barley (Hordeum vulgare L.) were following each other. There were two production variants which followed the crop rotation. In one variant mineral fertilizers and pesticides were used, and the other variant was conversion to organic without any synthetic agrochemicals. In mineral fertilizing variant, on the background of P25 and K95 kg haE-1 the N amount varied from 0 to 150 kg haE-1 and herbicide Mustang (preparation norm 0.5 L haE-1, active substance florasulam, 6.25 g LE-1; 2.4-D, 300 g LE-1), insecticide Fastac 50 (preparation norm 0.2 L haE-1, active substance 50 g LE-1 alphacypermethrin) fungicide Falcon EC 460 (preparation norm 0.4 L haE-1, active substances 167 g tebuconazole, 250 g spiroxamine, 43 g triadimenol) and growth regulator Moddus (preparation norm 0.4 L haE-1, active substance 250 g LE-1 trinexapac-ethyl) were used. In conversion to organic the winter wheat grains which followed the red clovers after effect had higher volume weight, 1000 kernel weight and gluten index compared to the variants where mineral fertilizers were used. The yield, protein content, falling number and gluten content in dry matter increased with increase of the amount of mineral N. The wet gluten content was significantly higher compared to the other variants where the N amount was 50 kg haE-1.
Показать больше [+] Меньше [-]Use of heat exchangers in ventilation systems of pigsties in dependence on outside air temperature Полный текст
2010
Zagorska, V., Latvia Univ. of Agriculture, Jelgava (Latvia) | Jesko, Z., Latvia Univ. of Agriculture, Jelgava (Latvia) | Ilsters, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
To raise the level of energy efficiency of the ventilation systems of pigsties it is useful to introduce heat exchangers. A heat exchanger is a device built for efficient heat transfer from one medium to another. In the case when a heat exchanger is used in the ventilation systems of premises of pigsties, clean and cold air (in the autumn-winter period) gets amount of heat energy from unclean but warm inside air. Respiration of pigs and the processes occurring on the surface of manure cause the generation of carbon dioxide and ammonia, which are considered harmful gases not only for people and animals but also for the equipment, high relative humidity that occurs also during respiration of pigs influences working conditions as well. The article deals with experimental results obtained from the experiments about plate counter-flow heat exchanger models with plastic cellular boards (HE PVC) and plastic plates (WVT-120K) as heat transfer surfaces. Operational parameters describing the energy efficiency of heat exchangers were calculated – power of recovered heat energy (kW), heat transfer coefficient (WmE-2 deg CE-1), and coefficient of efficiency by recovered heat. Due to better operational parameters of experimental recuperative outflow heat exchanger (HE PVC) simulation and analysis of its exploitation during 4 seasons (December/January) depending on outside air temperature in the article are made as well. The possibility of development of ESA heat exchanger construction with built-in tubular electrical heater to preheat outside air (at outside air temperatures below -15 deg C) has been carried out in the research.
Показать больше [+] Меньше [-]Emission reduction potential of using biofuels Полный текст
2010
Pirs, V., Latvia Univ. of Agriculture, Jelgava (Latvia) | Dukulis, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
One of the primary reasons for expanding the production and use of biofuels is the potential environmental benefit that can be obtained from replacing fossil fuels with fuels derived from renewable biomass resources. This investigation examines the impact of biofuels on the environment directly from the practical view point analysing how the internal combustion engine emission concentration changes using the most common first-generation biofuels in Latvia – biodiesel, rapeseed oil and bioethanol. Laboratory experiments were performed on a chassis dynamometer Mustang MD1750, but the content of exhaust gases components was determined by the AV L SESAM FTIR measurement system. Investigation shows that the trends of different exhaust gas component changes, which would be the same for all investigated fuels, don't exist, i.e., each vehicle and biofuel type or blend is particular and has to be analysed separately. In comparison with fossil diesel, running the car VW Golf on rapeseed oil the average reduction of NOx was 10%, but SO2 – 59%. The CO, CO2, unburned hydrocarbon and mechanical particle emissions were higher. Running the car Opel Vectra on biodiesel the amount of NOx in comparison with fossil diesel increased in average by about 12%, the amount of mechanical particles and unburned hydrocarbons decreased quite significantly, but just a small increase of CO and SO2 was observed. Testing the car VW Passat on gasoline-bioethanol blends increase of the bioethanol content in the fuel blend increased also the NOx content in exhaust gases, but the content of CO, CO2 and NH3 decreased.
Показать больше [+] Меньше [-]The influence of biomass type on quantitative and qualitative indicators of biogas Полный текст
2010
Straume, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
The utilization of traditional fossil fuels (oil, gas) as primary energy resources causes a destabilization of the eco-environmental situation in the world. Latvia has to significantly decrease energy imports from its neighbouring countries. This can be achieved by using high-quality local primary renewable energy sources. One of the solutions is to utilize anaerobic fermentation for biogas production. This process can be ensured by utilizing manure, food waste as well as energy biomass - wood, grass and maize. Biogas is utilized as a primary energy source in a cogeneration plant which is a combined cycle plant for electricity and heat power production. Microcogeneration plant for farming household needs would ensure an independent power supply, in case the overall electrical network is in a state of emergency. In order to ensure optimal biogas yield, which, in turn, would ensure a stable operation of the microcogeneration plant, it is important to know the parameters and quality of the biomass that have been filled in bioreactor. This research deals with the influence of the linkage biomass type on the qualitative and quantitative indicators of biogas. As a result, it has been found that biomass type affected the methane percentage in biogas greatly. The methane content of biogas independent with biomass type was diminished from 65% (galega) to 44.5% (fresh sawdust), but biogas yield decreased from 0.627 m**3 kgVSd E-1 (galega) to 0.185 m**3 kgVSd E-1 (fresh sawdust).
Показать больше [+] Меньше [-]Sensory and qualitative indices (hardness and colour) evaluation of cakes with Jerusalem artichoke (Helianthus tuberosus L.) powder Полный текст
2010
Gedrovica, I., Latvia Univ. of Agriculture, Jelgava (Latvia) | Karklina, D., Latvia Univ. of Agriculture, Jelgava (Latvia) | Straumite, E., Latvia Univ. of Agriculture, Jelgava (Latvia)
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.
Показать больше [+] Меньше [-]Physical-chemical evaluation of sous vide cooked parent stock hen breast meat during refrigerated storage Полный текст
2010
Ramane, K., Latvia Univ. of Agriculture, Jelgava (Latvia) | Galoburda, R., Latvia Univ. of Agriculture, Jelgava (Latvia) | Murniece, I., Latvia Univ. of Agriculture, Jelgava (Latvia) | Dukalska, L., Latvia Univ. of Agriculture, Jelgava (Latvia)
The aim of this study was to evaluate physical and chemical changes in sous vide cooked marinated parent stock hen breast meat during refrigerated storage. Sous vide method is suitable for preparation of ready-to-eat meat products satisfying consumer demand for convenience and safety. Meat tenderness is recognized as important quality attribute of meats. The study involved preparation of the raw material, vacuum packaging of the products in polyamide/polyethylene (PA/PE) film pouches, marinating for 20 hours, sous vide cooking and chilling in ice water, followed by storage at 3.0±0.5 deg C. Each sample containing a chicken portion or chicken mix with shredded carrots, sea buckthorn sauce and spices was analysed during storage. Water activity, pH, and moisture were assessed during storage. Hardness (shear force) measurement was used as an instrumental method for meat tenderness evaluation. The differences between two studied products were noted regarding all studied parameters – water activity, pH, moisture content, and hardness. The differences mainly were determined by the properties of carrot and sea buckthorn additive, which generally have higher moisture content and lower pH. The researched parameters were well preserved during refrigerated storage for 28 days.
Показать больше [+] Меньше [-]Promising European Union supported initiatives within private forest sector in Latvia Полный текст
2010
Nikolajeva, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
The aim of this paper is to evaluate all kinds of experiences with attractive EU funding for Latvia's private forest sector in the past and to generate new proposals for effective acquisition in near future. Latvian institution may learn from these experiences in order to improve their (acquisition) role in project proposals for the private forest sector. Consequently, the relatively underdeveloped Latvian private forest sector will get its highly needed support for better performance, and progress towards other, leading EU forest sectors. The possibilities for attractive financial EU support are reviewed through both historic experiences with the EU's 'Rural Development Program for 2007 – 2013' and the EU grants, designated for forestry projects. An extensive round of interviews is held with state forest owners and experts involved in forest management programmes and other dedicated EU forest funding initiatives. Following the expert interviews, two key indicators are developed to evaluate the support from the EU. Contacts with the EU countries (the Netherlands, Belgium, Finland and Poland) where similar forestry activities have been done as in Latvia were made. Research done in this work is unique as according to the author's information these countries do not have similar research related to the EU funds efficiency and Rural Development Program for 2007 – 2013. The successfulness of Latvian applications for the EU funding is one major indicator for further fund raising. The EU supported investments generally have higher economic results in comparison with their non EU funded counterparts.
Показать больше [+] Меньше [-]