Research in Agricultural Engineering, 2012 (vol. 58), issue 4
Index of volume 58Index
editors
Res. Agr. Eng., 2012, 58(4):I-II | DOI: 10.17221/6484-RAE 
Evaluation of reed canary grass (Phalaris arundinacea L.) grown for energy use
Z. Strašil
Res. Agr. Eng., 2012, 58(4):119-130 | DOI: 10.17221/35/2011-RAE
Field experiments with reed canary grass were conducted during 1996-2000 at four different sites (Ruzyně, Troubsko, Lukavec and Chomutov in the Czech Republic). In the period 2001-2009 the experiments were run at Ruzyně and Lukavec. During vegetation the following indicators were monitored: the course of weather in individual years at given sites and infestation of stands by pests and diseases. Furthermore, we monitored the effects of N application rates, year, site, as well as the effect of harvest time on yields of harvested biomass, moisture content, elements content, and energy content. The content of heavy metals in soils and subsequently in plants...
Determination of the technical parameters of shaping tools for delimbing head
M. Mikleš
Res. Agr. Eng., 2012, 58(4):131-135 | DOI: 10.17221/51/2011-RAE
It is usually a technical problem to find mathematical ideal shape of knives of delimbing head. Determination of their shape in the form of general curve could lead to the technically unfeasible dimensions of the head. Criterion of the optimal shape of cutting contour of head is tightness of encirclement of cross section of trunk by knives. Research attention was aimed at conics. Parabola is the most suitable curve for achieving the best quality of delimbing.
Optimisation of a clam bunk skidder from the emission production point of view
A. Janeček, R. Adamovský
Res. Agr. Eng., 2012, 58(4):136-141 | DOI: 10.17221/63/2011-RAE
This article presents a proposal of a simple mathematical model for minimisation of the production of extraneous substances as a function of the rate of operation performance of a production system. The model is then verified by operation tests of the Terri 2040 clam bunk skidder and by determining the system's optimal rate of performance from the point of view of production of SO2, HC and NOx emissions. The operation tests conducted to verify the mathematical model have confirmed that conditions can be determined for the production system at which it produces minimum emissions. Min. values of SO2, and HC were achieved...
Ear tag mechanical properties under extreme climate conditions
M. Müller, D. Lukešová
Res. Agr. Eng., 2012, 58(4):142-147 | DOI: 10.17221/65/2011-RAE
The common ear tag production and application do not take into regard the demographic environment and climate of a target destination which are specified. However, this fact becomes a core of the problem. The necessity to characterize the ear tag bond comes out from the practical experience when applying incorrect exchange spike in the application punch by mistake. The aim of the experimental research was to carry out the evaluation of the ear tag mechanical qualities under increased and decreased temperatures on the base of the laboratory experiments together with the suitable and incorrect application of the exchange spike in the application punch....
Analysis of strength ratio of different hop strings
P. Heřmánek, A. Rybka, I. Honzík, L. Vent, B. Jošt, J. Mašek
Res. Agr. Eng., 2012, 58(4):148-154 | DOI: 10.17221/33/2012-RAE
In plant-growing, minimization of impurities in the final product plays a more and more important role. One of the risky places that can influence the final purity of granules in hop growing is the way of hop strings hanging on the trellis supporting wire. The ideal state is when hop-field supporting wires stay clean and without any attachments after the hop vines had been pulled down. The article deals with different variants of hop strings hanging, a description of the measuring equipment, and a measurement of the pulling force itself at a field test, and a realization of break tests in laboratory conditions with both new and used wires and twines....
Model for energy and deformation determination of selected oilseeds under compression loading - Short communication
A. Kabutey, D. Herák, R. Chotěborský, M. Navrátilová
Res. Agr. Eng., 2012, 58(4):155-158 | DOI: 10.17221/17/2011-RAE
Compression loading test was performed to determine the dependency between force and deformation of jatropha, sunflower and rape seeds with respect to different pressing seed volume. Parameters such as max. deformation and energy were measured. The results which were statistically significant at (P < 0.05) show that rape seed with lower deformation values utilized greater energy than the seeds of jatropha and sunflower which obtained higher deformation values in that order of magnitude. The energy (J) was determined by the area under the force-deformation curve while deformation (mm) was obtained directly from the compression test. Based...