Template-Type: ReDIF-Article 1.0 Author-Name: J. Blahovec Author-Workplace-Name: Faculty of Technology, Czech University of Life Sciences in Prague, Prague, Czech Republic Author-Name: J. Sobotka Author-Workplace-Name: Faculty of Technology, Czech University of Life Sciences in Prague, Prague, Czech Republic Title: Potato tuber permittivity during deformation in compression Abstract: Potato tuber specimens of two varieties (Nicola and Saturna) were deformed in a compression loading/unloading test. The tuber complex permittivity spectrum at frequencies 0.1-500 kHz was measured repeatedly during the deformation. The results show that both parts of relative permittivity (real and imaginary) decrease with increasing deformation and vice versa. The same trend was observed at all studied frequencies even if it was not equally strong in all cases. The permittivity plots versus frequency were similar in both the tested varieties and in different stages of deformation. The influence of tuber deformation on the permittivity values as well as the reversibility of the permittivity changes during the deformation are changed substantially at strains about 20% in comparison to strains up to 10%. The obtained results support the hypothesis that permittivity measurements can serve as an alternative indication of the internal structural changes in potato tissue during its loading. Keywords: potato, permittivity, frequency, deformation, strain, reversibility Journal: Research in Agricultural Engineering Pages: 79-84 Volume: 53 Issue: 3 Year: 2007 DOI: 10.17221/2124-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/2124-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200703-0001.txt Handle: RePEc:caa:jnlrae:v:53:y:2007:i:3:id:2124-RAE Template-Type: ReDIF-Article 1.0 Author-Name: J. Vegricht Author-Workplace-Name: Research Institute of Agricultural Engineering, Prague-Ruzyně, Czech Republic Author-Name: P. Miláček Author-Workplace-Name: Research Institute of Agricultural Engineering, Prague-Ruzyně, Czech Republic Author-Name: P. Ambrož Author-Workplace-Name: Research Institute of Agricultural Engineering, Prague-Ruzyně, Czech Republic Author-Name: A. Machálek Author-Workplace-Name: Research Institute of Agricultural Engineering, Prague-Ruzyně, Czech Republic Title: Parametric analysis of the properties of selected mixing feeding wagons Abstract: Eight different mixing feeding wagons (MFW) were investigated under identical conditions in preparing total mixed rations (TMR) for three various cattle categories. Investigated were the uniformity of distribution of the feed into the trough, homogeneity of TMR distributed, the machine capacity in feed extracting from storage and loading, TMR mixing and distributing into the trough, fuel consumption and power consumption required. The least uniformity was found for TMR with a high hay proportion (average value of standard deviation 49.9%). Better results were achieved with MFW designed with horizontal mixing augers (average standard deviation 33.7%). MFW with vertical augers distributed feeds at average standard deviation of 61.3%. Standard deviation of the proportion of feed particles on the separator screens which is considered as a measure of TMR homogeneity, was bellow 20% in most cases. This suggests a hint of a very good mixing efficiency of all the MFW followed up. No influence of different designs of the working elements of MFW on TMR homogeneity has been proved. With respect to the machine capacity (output) in preparing and distributing TMR, no large differences between various MFW were found and their output averaged from all measurements varied within the range of 4.79-5.48 t/h. The least average specific consumption of fuel for preparing and distributing TMR was found in the MFW equipped with vertical mixing augers (1.10-1.11 l/t). MFW with one horizontally mounted mixing auger showed a rather higher fuel consumption (1.30-1.43 l/t). The highest fuel consumption was found with MFW equipped with two parallely mounted mixing augers (1.59-1.63 l/t). Keywords: mixing feeding wagons, cattle feeding, total mixed rations, output, fuel consumption Journal: Research in Agricultural Engineering Pages: 85-93 Volume: 53 Issue: 3 Year: 2007 DOI: 10.17221/2123-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/2123-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200703-0002.txt Handle: RePEc:caa:jnlrae:v:53:y:2007:i:3:id:2123-RAE Template-Type: ReDIF-Article 1.0 Author-Name: P. Jevič Author-Workplace-Name: Research Institute of Agricultural Engineering, Prague, Czech Republic Author-Workplace-Name: Department of Technological Equipment of Buildings, Faculty of Technology, Czech University of Life Sciences in Prague, Prague, Czech Republic Author-Name: P. Hutla Author-Workplace-Name: Research Institute of Agricultural Engineering, Prague, Czech Republic Author-Name: J. Malaťák Author-Workplace-Name: Department of Technological Equipment of Buildings, Faculty of Technology, Czech University of Life Sciences in Prague, Prague, Czech Republic Author-Name: Z. Šedivá Author-Workplace-Name: Research Institute of Agricultural Engineering, Prague, Czech Republic Title: Efficiency and gases emissions with incineration of composite and one-component biofuel briquettes in room heater Abstract: In accordance with the technical standard ČSN EN 13229 "Inset appliances for heating including open fires fired by solid fuels - Requirements and test methods" was performed the basic assessment of thermal efficiency and emission parameters of prototype of combustion accumulation stove SK-2 with upper after-burning and nominal heat output of 8 kW. Verified gradually were the bio-briquettes of diameter 65 mm from mixture of wheat straw and 20% m/m of brown coal, wheat straw and 5% m/m of brown coal, wheat straw, mixture of wheat straw and 10% m/m of water and molasses solution, Ecobiopal created with the fermented blend of 33% m/m of digested clean water plant sludge and 67% m/m of wood chopped material, blend of wheat straw and 15% m/m of sugar beet pulp, mixture of timothy hay and 25% m/m of brown coal, timothy grass hay, meadow hay, mixture of meadow hay and 25% m/m of brown coal. The lowest CO emissions, when the limit value of 3000 mg/m3N at 13% of O2 has not been exceeded, determined for more strict 1st class and the highest efficiency at nominal heat performance, i.e. higher or equal to 70% (Class I) have been reached by the briquettes produced from mixture of wheat straw and 15% m/m of sugar beet pulp, timothy hay and mixture of meadow hay with addition of 25% m/m of brown coal. Further were measured NOx and HCl emissions. NOx values were significantly lower than limit values determined for similar combustion of solid biofuel. Higher differences of HCl emissions correlate with various Cl content in fuels. Only the wheat straw briquettes with share of 25% m/m of brown coal have exceeded the limit value by 16%. Other fuels have shown considerably lower values. The results have proved better heat-technical and emission parameters of blended briquettes and are significant also for solid biofuels and solid recovered fuels standardization as well as for increasing efficiency method detection and ecological parameters optimization including HCl emissions. Keywords: biofuel briquette, composite briquette, combustion, efficiency, combustion gases, emission Journal: Research in Agricultural Engineering Pages: 94-102 Volume: 53 Issue: 3 Year: 2007 DOI: 10.17221/2125-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/2125-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200703-0003.txt Handle: RePEc:caa:jnlrae:v:53:y:2007:i:3:id:2125-RAE Template-Type: ReDIF-Article 1.0 Author-Name: V. Messingerová Author-Workplace-Name: Faculty of Forestry, Technical University in Zvolen, Zvolen, Slovak Republic Author-Name: J. Tajboš Author-Workplace-Name: Faculty of Forestry, Technical University in Zvolen, Zvolen, Slovak Republic Title: Exposition of working and natural environment to noise during timber transport by helicopter MIL MI-8 in Carpathian region of Slovakia Abstract: This paper includes the results of noise measurements during timber transport by helicopter MI-8 in The High Tatras conditions in 2005. Using this highly efficient timber skidding technology with multiple positive environmental properties causes an unwanted effect - air-traffic noise. The objective of this paper is to quantify the level of noise effect for two correlated groups; noise effecting workers and noise effecting environment. The highest values measured in the worst conditions reached 90-100 dB (A). Keywords: helicopter, timber skidding, noise, environment, analysis Journal: Research in Agricultural Engineering Pages: 103-110 Volume: 53 Issue: 3 Year: 2007 DOI: 10.17221/2127-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/2127-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200703-0004.txt Handle: RePEc:caa:jnlrae:v:53:y:2007:i:3:id:2127-RAE Template-Type: ReDIF-Article 1.0 Author-Name: M. Bošanský Author-Workplace-Name: Department of Machine Parts, Faculty of Mechanical Engineering, Slovak University of Technology in Bratislava, Bratislava, Slovak Republic Author-Name: I. Kožuch Author-Workplace-Name: Department of Machine Parts, Faculty of Mechanical Engineering, Slovak University of Technology in Bratislava, Bratislava, Slovak Republic Author-Name: M. Vereš Author-Workplace-Name: Department of Machine Parts, Faculty of Mechanical Engineering, Slovak University of Technology in Bratislava, Bratislava, Slovak Republic Title: Cylindrical screw gearing with parallel axes of rotation Abstract: In the first part the article describes the theory of cylindrical screw gearing and in second part it states an alternative solution of screw gearing with parallel axes of rotation. There are given results of relating correctness of gear meshing and its manufacturing as theoretical problem. Authors present possibilities of screw gearing with parallel axes of rotation in area of agricultural machine application too. Keywords: cylindrical screw gearing, correct gear meshing, gearing, agricultural machine Journal: Research in Agricultural Engineering Pages: 111-115 Volume: 53 Issue: 3 Year: 2007 DOI: 10.17221/2128-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/2128-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200703-0005.txt Handle: RePEc:caa:jnlrae:v:53:y:2007:i:3:id:2128-RAE Template-Type: ReDIF-Article 1.0 Author-Name: R. Chotěborský Author-Workplace-Name: Department of Material Science and Manufacturing Technology, Faculty of Technology, Czech University of Life Sciences in Prague, Prague, Czech Republic Author-Name: P. Hrabě Author-Workplace-Name: Department of Material Science and Manufacturing Technology, Faculty of Technology, Czech University of Life Sciences in Prague, Prague, Czech Republic Author-Name: M. Müller Author-Workplace-Name: Department of Material Science and Manufacturing Technology, Faculty of Technology, Czech University of Life Sciences in Prague, Prague, Czech Republic Title: Properties of martensitic overlays Abstract: The abrasive wear resistance of martensitic overlays is the function of many variables. The hardness is one of the variables. This fact is raised by the possibility of carbidic phases separating from the austenite in the course the overlay layer cooling and by the possibility of the further martensite disintegration and carbidic phases precipitation. The paper is engaged in the hardness and abrasive wear resistance problems of one-layer martensitic overlays. Keywords: welding, overlay material, abrasive wear Journal: Research in Agricultural Engineering Pages: 116-120 Volume: 53 Issue: 3 Year: 2007 DOI: 10.17221/2126-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/2126-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200703-0006.txt Handle: RePEc:caa:jnlrae:v:53:y:2007:i:3:id:2126-RAE