Research in Agricultural Engineering, 2008 (vol. 54), issue 1
The effect of the tractor engine rated power on diesel fuel consumption during material transport
L. Jílek, R. Pražan, V. Podpěra, I. Gerndtová
Res. Agr. Eng., 2008, 54(1):1-8 | DOI: 10.17221/710-RAE 
The authors of this paper determined in a field measurement how the change of the tractor engine power in a tractor-trailer combination affects the diesel fuel consumption related to the unit of transport output (l/tkm) and the transport performance (t/h) in the conditions of a mountainous region. Transport combinations (tractor - trailer) were compared that were formed by a tipping trailer connected to three tractors with different engine powers when passing allong a route with the gradient of 0°-5.5°. It is obvious from the results of these measurements that the diesel fuel consumption differed by up to 27% in individual combinations. The lowest...
By-products from methyl ester oil production and their thermal-emission properties
J. Bradna, J. Malaťák
Res. Agr. Eng., 2008, 54(1):9-21 | DOI: 10.17221/707-RAE
With the exhaustion of fossil energy sources in sight, the importance of the renewable sources of energy becomes one of the major conditions for permanently sustainable development not only in agriculture, but also in the society as a whole. The growing use of biodiesel has opened other areas of utilising the by-products from the manufacture of rape seed oil methyl ester (FARME) as an energy source, used in the combustion equipment designed for these alternative fuels. The aim of this paper is to assess the feasibility of utilising the by-products from the production of rape seed methyl ester as a source of energy, from ecology and economy aspects...
Measurement of potato tubers resistance against mechanical loading
V. Mayer, D. Vejchar, L. Pastorková
Res. Agr. Eng., 2008, 54(1):22-31 | DOI: 10.17221/708-RAE
The contribution presents a method for the determination of the potato tubers resistance against mechanical loading, the measurement results obtained with the selected potato varieties, and the comparison of the latter. For testing the potato varieties samples, the method developed in Agrartechnik (ATB) Bornim (Germany) was verified and utilised. The potato samples were exposed to vertical vibrations with adjustable amplitude in the device constructed at the Research Institute of Agricultural Engineering, (RIAE) Prague, for testing tuber samples for mechanical loading. The potato samples cutting pictures were scanned by a web camera or a scanner, and...
Utilisation of the method of stress limit for designing the motion screw dimensions
D. Herák, J. Karanský, R. Chotěborský
Res. Agr. Eng., 2008, 54(1):32-41 | DOI: 10.17221/709-RAE
A design of the motion screw using the method of stress limit is described. Further general formulas are induced to design such kind of screws, applied to an example of 11500 (EN ISO E295) steel made screw, strained by static operational force. Safety equations to prevent screw drift and their diagrams are integrated parts of the article.