Research in Agricultural Engineering, 2009 (vol. 55), issue 1
Simulation mathematical model of expert system for working processes management
O. Syrový, V. Podpěra
Res. Agr. Eng., 2009, 55(1):1-9 | DOI: 10.17221/12/2008-RAE 
The elementary simulation mathematical models presented in this article are related with the sub-system Crop production of the expert system for the decision support in technological and working processes management and their optimisation. Along with this sub-system, the expert system also involves the sub-systems Livestock production and Material handling which is further divided into the parts Transport and Storage. The boundary between the individual parts of the expert system is usually a short-term or long-term material storage. The relative individual sub-systems are mutually connected through the information flow. For each of the sub-systems,...
Influence of sweet corn harvest date on kernels quality
M. Szymanek
Res. Agr. Eng., 2009, 55(1):10-17 | DOI: 10.17221/13/2008-RAE
Sweet corn has a very short period of optimum harvest maturity, and its quality changes rapidly close to and following the peak. The aim of this study was to determine the sweet corn quality on the ground of some physicochemical properties of intact kernels (moisture content, compression, shear and puncture force, bulk density, sugar and starch contents) and cut kernels (processing recovery, cut corn yield) at four subsequent harvest dates. The moisture content, sugars level, and ear yield decreased. The starch level, bulk density (intact and cut kernels), compression force, shear force and puncture force, processing recovery and cut corn yield increased....
Field experience with transmission oil EP Gear Synth 150
Z. Aleš
Res. Agr. Eng., 2009, 55(1):18-23 | DOI: 10.17221/7/2008-RAE
The machinery operated in agriculture and forestry has been required to use less harmful vital fluids since a few years ago. These requirements are highly urged especially for the machines which are operated close to aquatic resources, water flows, fields, and in forests. Biodegradable vital fluids seem as a suitable solution from the environmental viewpoint. On the other hand, from the technical viewpoint their usage seems sort of problematic. The author started to carry out long-term stability tests of biodegradable transmission oil and mineral transmission oil used in tractor end rear boxes in the dependence on the operating time. This article pinpoints...
Acid catalysed transesterification of animal waste fat
A. Prošková, Z. Kopicová, J. Kučera, L. Škarková
Res. Agr. Eng., 2009, 55(1):24-28 | DOI: 10.17221/20/2008-RAE
Rendering plant fat (RPF) was collected and different conditions were used for transesterification. The course of transesterification of RPF was compared with that of transesterification of lard under the same conditions. Significant diffe-rences were found between transesterification of RPF and that of lard. Optimum methanol excess for lard transesterification was found to be 30-fold, for RPF 10-fold, optimum sulfuric acid concentration was 1% for lard, 2.5% for RPF. Optimum temperature as well as optimum reaction time were similar in both cases. The fatty acid composition is similar but not identical in both fats. RPF contains a higher amount of...
Degradation processes influencing bonded joins
M. Müller, R. Chotěborský, P. Hrabě
Res. Agr. Eng., 2009, 55(1):29-34 | DOI: 10.17221/17/2008-RAE
Degradation processes cause huge material and economic losses all over the world. On one hand, in today's globalised society, various climatic changes occur affecting products in different ways. On the other hand, different specific degradation media exist in specific branches of the human activity. Due to the influence of the degradation environment (media), destruction can set in. The aim of the laboratory experiments was to evaluate the influence of the degradation environment occurring mainly in agriculture. The adhesive bond strength properties as well as the influence on adhesive bonded materials were evaluated. For the degrading environment...
Assessment of the current theory for projecting cableway routes in terms of the risk level in overloading
V. Štollmann, Š. Ilčík
Res. Agr. Eng., 2009, 55(1):35-38 | DOI: 10.17221/505-RAE
The article deals with the safety of labour and of technical equipment in timber skidding using forest cableways. It analyses the applicability of the current theory used for designing cableway routes from the point of view of safety in terms of an excessive overload. The analysis, which was carried out using situational models, has shown that the skyline will break as a result of several fold excess of the safe working load. The value of the buckling load is in such case at least 3.5 times higher than that of the safe working load. Our results have confirmed the applicability of the theory currently used in designing cableway routes.