Template-Type: ReDIF-Article 1.0 Author-Name: editors Title: Index of Volume 56 Journal: Research in Agricultural Engineering Pages: I-II Volume: 56 Issue: 4 Year: 2010 DOI: 10.17221/1630-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/1630-RAE.html File-Format: text/html Handle: RePEc:caa:jnlrae:v:56:y:2010:i:4:id:1630-RAE Template-Type: ReDIF-Article 1.0 Author-Name: V. Šleger Author-Workplace-Name: Faculty of Engineering, Czech University of Life Science Prague, Prague, Czech Republic Author-Name: P. Neuberger Author-Workplace-Name: Faculty of Engineering, Czech University of Life Science Prague, Prague, Czech Republic Title: Frequency of occurrence of a certain air temperature at various sites in the Czech Republic Abstract: The present paper analyses the problem of calculation of the average number of hours in a year during which air temperature is lower than a preselected limiting level. A method for estimating the number of hours in situations where only the minimum, average, and maximum daily temperature data are available has been suggested and tested. The work encompassed 30 sites in the Czech Republic at different altitudes and with different average temperatures, using weather data from the 1961-2000 period. The results are presented in the tabular form. It is shown that interdependence exists between the number of hours with temperatures lower than a preselected limiting level and the average yearly temperature at the specific site. For instance, temperatures below 15°C during a typical year at a site with an average yearly temperature θyr (°C) within the range of 2.8°C to 9°C can be expected (coefficient of determination 0.986) for a time τ (h) calculated from the quadratic equation τ = -12.992 × θyr 2 - 116.6 × θyr + 8,483. Keywords: climatic conditions, weather data, altitude, regression function Journal: Research in Agricultural Engineering Pages: 127-137 Volume: 56 Issue: 4 Year: 2010 DOI: 10.17221/4/2010-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/4/2010-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-201004-0002.txt Handle: RePEc:caa:jnlrae:v:56:y:2010:i:4:id:4-2010-RAE Template-Type: ReDIF-Article 1.0 Author-Name: J. Čupera Author-Workplace-Name: Department of Engineering and Automobile Transport, Faculty of Agronomy, Mendel University in Brno, Brno, Czech Republic Author-Name: T. Šmerda Author-Workplace-Name: Department of Engineering and Automobile Transport, Faculty of Agronomy, Mendel University in Brno, Brno, Czech Republic Title: The usage of CAN-Bus messages for engine power determination Abstract: Determination of the actual power of tractor's engine in the operation can be done by calculation which requires the use of a range of parameters such as coefficient of rolling resistance, mechanical efficiency, the moments of inertia, etc. Their values are usually tabulated and therefore the engine power cannot be determine without simplifying. Another solution is to use the actual engine torque message from the CAN-Bus, which brings a specific value of the actual torque. The aim is to use the current torque to calculate the engine power in the deployment of tractor's set in transport operation. The results show that at a uniform movement of the flat section the engine power reached 73 kW. When driving uphill, the value of the actual power reached from 130 to 150 kW depending on the selected gear. Using the actual parameters of torque makes possible to identify the known full speed characteristics of the current engine without the need for assembly demanding measurement techniques. Keywords: actual engine torque, engine, tractor, engine power, CAN-Bus Journal: Research in Agricultural Engineering Pages: 138-146 Volume: 56 Issue: 4 Year: 2010 DOI: 10.17221/45/2009-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/45/2009-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-201004-0003.txt Handle: RePEc:caa:jnlrae:v:56:y:2010:i:4:id:45-2009-RAE Template-Type: ReDIF-Article 1.0 Author-Name: M. Szostková Author-Workplace-Name: Department of Agrochemistry, Soil Science, Microbiology and Plant Nutrition, Faculty of Agronomy, Mendel University in Brno, Brno, Czech Republic Author-Name: T. Vítěz Author-Workplace-Name: Department of Agriculture, Food and Environmental Engineering, Faculty of Agronomy, Mendel University in Brno, Brno, Czech Republic Title: Microbial contamination of the sand from the wastewater treatment plants Abstract: Primary treatment of domestic wastewater represents an extensive range of physical and chemical activities which directly or indirectly affect functionality of the treatment plant as a whole. The aforementioned effect might be rather significant in many respects. However, an incorrectly designed or operated primary treatment might result in an unnecessary increase of operating costs and, principally, a negative impact on the biological level or sludge treatment and disposal. The subject matter of this contribution comprises contemplations related to functionality of this level, both with respect to its relation to functionality of wastewater treatment plant and the matter of created waste in case of which disposal has become more and more expensive and complicated. The measurement results show that sewage sand from different wastewater treatment plants contains different amount of organic material 1.19-82%. The content of the organic material relates to the content of microorganisms which oscillated in a range of 1.53×104-7.34×106 CFU/g for coliform bacteria including Escherichia coli, 5.57×101-4.36×104 CFU/g for enterococci, and 3.13×102-2.19×105 CFU/g for faecal coliform bacteria. Keywords: wastewater treatment, primary treatment, detritus tank, wastewater treatment sand, microbial contamination Journal: Research in Agricultural Engineering Pages: 147-153 Volume: 56 Issue: 4 Year: 2010 DOI: 10.17221/21/2009-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/21/2009-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-201004-0004.txt Handle: RePEc:caa:jnlrae:v:56:y:2010:i:4:id:21-2009-RAE Template-Type: ReDIF-Article 1.0 Author-Name: T. Vítěz Author-Workplace-Name: Department of Agriculture, Food and Environmental Engineering, Faculty of Agronomy, Mendel University in Brno, Brno, Czech Republic Author-Name: P. Trávníček Author-Workplace-Name: Department of Agriculture, Food and Environmental Engineering, Faculty of Agronomy, Mendel University in Brno, Brno, Czech Republic Title: Particle size distribution of sawdust and wood shavings mixtures Abstract: Particle size distribution of the sample of waste sawdust and wood shavings mixtures were made with two commonly used methods of mathematical models by Rosin-Rammler (RR model) and by Gates-Gaudin-Schuhmann (GGS model).On the basis of network analysis distribution function F (d) (mass fraction) and density function f (d) (number of particles captured between two screens) were obtained. Experimental data were evaluated using the RR model and GGS model, both models were compared. Better results were achieved with GGS model, which leads to a more accurate separation of the different particle sizes in order to obtain a better industrial profit of the material. Keywords: wood shavings, sawdust, particle size distribution, modelling Journal: Research in Agricultural Engineering Pages: 154-158 Volume: 56 Issue: 4 Year: 2010 DOI: 10.17221/8/2010-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/8/2010-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-201004-0005.txt Handle: RePEc:caa:jnlrae:v:56:y:2010:i:4:id:8-2010-RAE Template-Type: ReDIF-Article 1.0 Author-Name: O. Dajbych Author-Workplace-Name: Department of Mechanical Engineering, Faculty of Engineering, Czech University of Life Sciences Prague, Prague, Czech Republic Author-Name: D. Herák Author-Workplace-Name: Department of Mechanical Engineering, Faculty of Engineering, Czech University of Life Sciences Prague, Prague, Czech Republic Author-Name: A. Sedláček Author-Workplace-Name: Department of Mechanical Engineering, Faculty of Engineering, Czech University of Life Sciences Prague, Prague, Czech Republic Author-Name: G. Gűrdil Author-Workplace-Name: Department of Agricultural Machinery, Faculty of Agriculture, Ondokuz Mayis University Samsun, Samsun, Turkey Title: Determination of loading capacity depending on bevel angle of the wooden bonded scarf joint Abstract: The paper is focused on comparison of experimental and simple theoretical method of determination of loading capacity depending on bevel angle of wooden bonded scarf joint. The Mohr's circle principle, thus shear stress dependence on normal stress, is used for loading capacity formula derivation. It has been established that for random bevel angle under approximately 70 degrees the future loading capacity can be calculated from knowledge of ultimate force for bevel angle 0 and 90 degrees. Keywords: scarf joint, bonded joint, wood, loading capacity, Mohr's circle Journal: Research in Agricultural Engineering Pages: 159-165 Volume: 56 Issue: 4 Year: 2010 DOI: 10.17221/1/2010-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/1/2010-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-201004-0006.txt Handle: RePEc:caa:jnlrae:v:56:y:2010:i:4:id:1-2010-RAE