Research in Agricultural Engineering, 2009 (vol. 55), issue 2
Influence of fan flat nozzles wear degree on drop tracks size
M. Koszel
Res. Agr. Eng., 2009, 55(2):39-44 | DOI: 10.17221/25/2008-RAE 
The subject of the analysis was the influence of working parameters (working pressure and working speed) on the drop tracks size and changes in the flow rate level from flat fan nozzles. New nozzles were tested. It was found that the increase in the flow rate depends on the nozzles size and their working time, and that the increase in the drop track size is caused by the nozzles wear. An excessively low working pressure or working speed causes drops merging. This phenomenon is especially dangerous when using nozzles with a considerable degree of wear for agricultural spray since it poses ecological threat to the environment.
Effects of moisture content, internode position and loading rate on the bending characteristics of barley strawOriginal Paper
H. Tavakoli, S.S. Mohtasebi, A. Jafari
Res. Agr. Eng., 2009, 55(2):45-51 | DOI: 10.17221/26/2008-RAE
This study was conducted with the aim to evaluate the effects of the moisture content, internode position, and loading rate on the bending characteristics of barley straw including bending stress and Young's modulus. In the study, 9 treatments were performed as randomised complete block design with 5 replications. The characteristics were determined at three moisture levels: 10%, 15%, and 20% wet basis, three loading rates: 5, 10, and 15 mm/min, and free internodes: the first, second, and third internodes. The results showed that both the bending stress and Young's modulus decreased with an increase in the moisture content and towards the third internode...
Physical properties of flax fibre for non-textile-use
K.-H. Kromer
Res. Agr. Eng., 2009, 55(2):52-61 | DOI: 10.17221/6/2008-RAE
Abstract: The industrial use of natural fibre has been continuously increasing since 1996. In the interior of cars, the percentage of fibre-reinforced multi-material parts may reach 40%. Quality management needs standards for measuring reliable physical properties. The aim of the article is to summarise the appropriate and approved methods for measuring geometrical, gravimetrical, and mechanical properties of flax fibre. Test standards are also needed for fibre-reinforced plastics, an additional method is explained and compared with the existing standards. The use of these methods is demonstrated using selected test data.
New mixtures and technologies for biogas production at biogas plants of agricultural type processing livestock slurry
J. Kára, Z. Pastorek, J. Mazancová, I. Hanzlíková
Res. Agr. Eng., 2009, 55(2):62-68 | DOI: 10.17221/3/2009-RAE
The basis of the biogas production in agriculture is the processing of waste agricultural products (particularly excrements of farm animals but also phytomass). Different but rather similar is the biogas production from biologically degradable municipal waste (BDMW) and biologically degradable industrial waste (BDIW) coming mainly from food industry. The processing of these wastes in agricultural biogas stations could significantly improve their economy. It is necessary to note that all these biogas stations differ from the wastewater cleaning plants where municipal sludge water from public sewers is processed. The municipal sludge water processing...
The exposure of working environment noise in the agricultural service workplaces
M. Šístková, A. Peterka
Res. Agr. Eng., 2009, 55(2):69-75 | DOI: 10.17221/23/2008-RAE
The noise belongs to the leading harmful factors which pollute the environment and negatively influences human health. An overview measurement concerning the noise characteristics has been done in agricultural service workplaces. The sound pressure level has been measured and the length of the workers exposition has been elicited in each workplace. The obtained data has proved that some agricultural service workers have been exposed to a noise above the permissible exposure limit.
Loading capacity determination of the wooden scarf joint
D. Herák, M. Müller, R. Chotěborský, O. Dajbych
Res. Agr. Eng., 2009, 55(2):76-83 | DOI: 10.17221/22/2008-RAE
The paper describes the complete derivation of the theoretical bonded scarf joint loading capacity and the construction of the Mohr's circle for linear state of stress. Then the method of the experimental determination of the bonded joint loading capacity is explained in detail. A part of this paper deals also with the bonded joint real loading capacity determination.