Template-Type: ReDIF-Article 1.0 Author-Name: Z. Abrham Author-Workplace-Name: Research Institute of Agricultural Engineering, Prague, Czech Republic Author-Name: M. Kovářová Author-Workplace-Name: Research Institute of Agricultural Engineering, Prague, Czech Republic Author-Name: T. Kuncová Author-Workplace-Name: Research Institute of Agricultural Engineering, Prague, Czech Republic Title: Technology and economy of energy crops Abstract: The cost modelling for growing and harvest of selected energy crops and further costs for recommended forms of energy crops processing to biofuels was conducted. Importance and effect of subsidies on resulted costs for biofuels production was assessed. The result are then total costs per unit of fuel weight which range from 469 to 1,806 CZK/t for biofuels processed to form of chopped material or pressed bales and from 881 to 2,466 CZK/t for briquettes and pellets. The result costs per energy unit in biofuel have ranged from 59 to 121 CZK/GJ. On basis of economical data is evaluated the biofuels competitive power in comparison with main competitive fuels on market. The energy crops specific costs without subsidies are higher thus their position on market will be complicated, lower specific costs can be expected only when residual biomass would be utilised (grain straw). The competitive power of the energy crops will be much better as the subsidies are utilised in 2004 and total specific costs for chopped material are from 82 to 142% of brown coal price, 95-137% for briquettes in comparison with the brown coal briquettes. The energy utilisation if winter wheat and sorghum is economically unsuitable. Keywords: sorrel, knotweed, reed canary grass, winter wheat, sorghum, triticale, maize, economy of growing, solid biofuels, subsidies Journal: Research in Agricultural Engineering Pages: 123-129 Volume: 50 Issue: 4 Year: 2004 DOI: 10.17221/4938-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/4938-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200404-0001.txt Handle: RePEc:caa:jnlrae:v:50:y:2004:i:4:id:4938-RAE Template-Type: ReDIF-Article 1.0 Author-Name: R. Adamovský Author-Workplace-Name: Technical Faculty, Czech University of Agriculture, Prague, Czech Republic Author-Name: D. Adamovský Author-Workplace-Name: Technical Faculty, Czech University of Agriculture, Prague, Czech Republic Author-Name: D. Herák Author-Workplace-Name: Technical Faculty, Czech University of Agriculture, Prague, Czech Republic Title: Exergy of heat flows of the air-to-air plate heat exchanger Abstract: Based on extensive measurements of the temperature, humidity and flow rate of the heated and cooled air in the plate heat exchanger this article analyses the influence of air inlet temperatures on both the exergy efficiency of the heat exchanger and the heat loss exergy. Furthermore, it describes the dependence between the thermal and exergy efficiency of the heat exchanger. The analysis of the tested heat exchanger indicated that the exergy efficiency of heat utilization from cooled air increases with rising inlet air temperature different, while the exergy efficiency of the heat transfer from cool to heated air decreases. In addition, the experiments confirmed the validity of the relationship between heat loss exergy and the values of air inlet temperatures. Keywords: heat exchanger, air, efficiency, energy, exergy, anergy, heat flow, stables Journal: Research in Agricultural Engineering Pages: 130-135 Volume: 50 Issue: 4 Year: 2004 DOI: 10.17221/4939-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/4939-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200404-0002.txt Handle: RePEc:caa:jnlrae:v:50:y:2004:i:4:id:4939-RAE Template-Type: ReDIF-Article 1.0 Author-Name: D. Plíštil Author-Workplace-Name: Technical Faculty, Czech University of Agriculture, Prague, Czech Republic Author-Name: M. Brožek Author-Workplace-Name: Technical Faculty, Czech University of Agriculture, Prague, Czech Republic Author-Name: J. Malaťák Author-Workplace-Name: Technical Faculty, Czech University of Agriculture, Prague, Czech Republic Author-Name: P. Heneman Author-Workplace-Name: Technical Faculty, Czech University of Agriculture, Prague, Czech Republic Title: Heating briquettes from energy crops Abstract: The aim of this research is to find and to evaluate energy crops with respect to their compactibility. It resulted in an evaluation of mechanical properties of seven crop species and in findings concerning mechanical parameters that exert influence on the compacting process. The evaluated mechanical properties cover the briquette density and the force required to break the briquettes. Following energy crops were studied: Sorghum vulgare, Phalaroides arundinacea, Crambe abyssinica, Fectusa pragensia, Camelina sativa, Miscanthus sinensis, Carthamus tinctorius. Before compression these crops were disintegrated in a grinder. The fraction size was given by the sieve mesh size - viz. a circular cross section of a 15 mm diameter. All crops had an unchanged moisture content during the measurement and a uniform output diameter of the briquette of about 65 mm. The crops showed following moisture contents in the experiments: Sorghum vulgare = 10.95%, Phalaroides arundinacea = 11.40%, Crambe abyssinica = 15.97%, Fectusa pragensia = 10.66%, Camelina sativa = 15.37%, Miscanthus sinensis = 9.97%, Carthamus tinctorius = 15.54%. Keywords: phytomass, energy crops, briquetting, mechanical properties, fissure test Journal: Research in Agricultural Engineering Pages: 136-139 Volume: 50 Issue: 4 Year: 2004 DOI: 10.17221/4940-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/4940-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200404-0003.txt Handle: RePEc:caa:jnlrae:v:50:y:2004:i:4:id:4940-RAE Template-Type: ReDIF-Article 1.0 Author-Name: T. Taşkin Author-Workplace-Name: Ege University, Faculty of Agriculture, Department of Animal Science, Izmir, Turkey Author-Name: A. Kaplan Author-Workplace-Name: Ege University, Faculty of Agriculture, Department of Animal Science, Izmir, Turkey Author-Name: A. Önenç Author-Workplace-Name: Ege University, Faculty of Agriculture, Department of Animal Science, Izmir, Turkey Author-Name: C. C Hepcan Author-Workplace-Name: Ege University, Faculty of Agriculture, Department of Animal Science, Izmir, Turkey Title: Evaluation of cattle and sheep buildings with their surroundings using 'visual quality assessment' technique Abstract: This study was conducted to assess visual quality of cattle and sheep housings with their surroundings across the seven districts of İzmir province, located in western side of Turkey. A total of 58 animal farms consisting of 31 cattle and 27 sheep farms were investigated. After watching the videos of all animal housings with their environs, each sample lasts for approximately 60 seconds, the 250 photos derived from the video scenes were evaluated by an expert group of 30 respondents in one panel. The respondents were asked to rate visual quality of each photo and its features on a five-point scale in order of district and farm type (cattle or sheep). The results showed that efficiently constructed and managed animal farm buildings in compliance with their surroundings were rated higher than the ones that are built on an ad hoc basis as well as irrelevant to their environs. Visual quality scores increased directly with natural landscape features (topographic attributes such as hill and plain, the presence of plant cover) and decreased with the mostly presence of man-made elements (transformer and electric lines, road, water channel, settlement) besides unplanned layout of the buildings and its facilities, proximity to highway and urban/rural settlements, worse manure management. Keywords: animal building, visual quality assessment, cattle and sheep farms, agricultural landscape Journal: Research in Agricultural Engineering Pages: 140-151 Volume: 50 Issue: 4 Year: 2004 DOI: 10.17221/4941-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/4941-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200404-0004.txt Handle: RePEc:caa:jnlrae:v:50:y:2004:i:4:id:4941-RAE Template-Type: ReDIF-Article 1.0 Author-Name: R. Chotěborský Author-Workplace-Name: Technical Faculty, Czech University of Agriculture, Prague, Czech Republic Author-Name: M. Brožek Author-Workplace-Name: Technical Faculty, Czech University of Agriculture, Prague, Czech Republic Title: Influence of heat treatment on mechanical properties of steel Abstract: This article concerns an influence of heat treatment on strength and toughness of steel. The partial results of tests on steel 12　042 are presented. Keywords: heat treatment, strength, toughness Journal: Research in Agricultural Engineering Pages: 152-155 Volume: 50 Issue: 4 Year: 2004 DOI: 10.17221/4942-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/4942-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200404-0005.txt Handle: RePEc:caa:jnlrae:v:50:y:2004:i:4:id:4942-RAE Template-Type: ReDIF-Article 1.0 Author-Name: J. Honců Author-Workplace-Name: Technical University in Liberec, Liberec, Czech Republic Title: The spring of internal combustion engine valve mechanism Abstract: This article deals with computational research of piston engine valve train including helical spring with variable number of active coils. This engine is destined for passenger car and therefore is featured by wide range of operational speed. Keywords: spring, valve spring, valve linkage, IC engines Journal: Research in Agricultural Engineering Pages: 156-159 Volume: 50 Issue: 4 Year: 2004 DOI: 10.17221/4943-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/4943-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200404-0006.txt Handle: RePEc:caa:jnlrae:v:50:y:2004:i:4:id:4943-RAE