Research in Agricultural Engineering, 2007 (vol. 53), issue 3
Potato tuber permittivity during deformation in compression
J. Blahovec, J. Sobotka
Res. Agr. Eng., 2007, 53(3):79-84 | DOI: 10.17221/2124-RAE 
Potato tuber specimens of two varieties (Nicola and Saturna) were deformed in a compression loading/unloading test. The tuber complex permittivity spectrum at frequencies 0.1-500 kHz was measured repeatedly during the deformation. The results show that both parts of relative permittivity (real and imaginary) decrease with increasing deformation and vice versa. The same trend was observed at all studied frequencies even if it was not equally strong in all cases. The permittivity plots versus frequency were similar in both the tested varieties and in different stages of deformation. The influence of tuber deformation on the permittivity values as well...
Parametric analysis of the properties of selected mixing feeding wagons
J. Vegricht, P. Miláček, P. Ambrož, A. Machálek
Res. Agr. Eng., 2007, 53(3):85-93 | DOI: 10.17221/2123-RAE
Eight different mixing feeding wagons (MFW) were investigated under identical conditions in preparing total mixed rations (TMR) for three various cattle categories. Investigated were the uniformity of distribution of the feed into the trough, homogeneity of TMR distributed, the machine capacity in feed extracting from storage and loading, TMR mixing and distributing into the trough, fuel consumption and power consumption required. The least uniformity was found for TMR with a high hay proportion (average value of standard deviation 49.9%). Better results were achieved with MFW designed with horizontal mixing augers (average standard deviation 33.7%)....
Efficiency and gases emissions with incineration of composite and one-component biofuel briquettes in room heater
P. Jevič, P. Hutla, J. Malaťák, Z. Šedivá
Res. Agr. Eng., 2007, 53(3):94-102 | DOI: 10.17221/2125-RAE
In accordance with the technical standard ČSN EN 13229 "Inset appliances for heating including open fires fired by solid fuels - Requirements and test methods" was performed the basic assessment of thermal efficiency and emission parameters of prototype of combustion accumulation stove SK-2 with upper after-burning and nominal heat output of 8 kW. Verified gradually were the bio-briquettes of diameter 65 mm from mixture of wheat straw and 20% m/m of brown coal, wheat straw and 5% m/m of brown coal, wheat straw, mixture of wheat straw and 10% m/m of water and molasses solution, Ecobiopal created with the fermented blend of 33% m/m of digested clean...
Exposition of working and natural environment to noise during timber transport by helicopter MIL MI-8 in Carpathian region of Slovakia
V. Messingerová, J. Tajboš
Res. Agr. Eng., 2007, 53(3):103-110 | DOI: 10.17221/2127-RAE
This paper includes the results of noise measurements during timber transport by helicopter MI-8 in The High Tatras conditions in 2005. Using this highly efficient timber skidding technology with multiple positive environmental properties causes an unwanted effect - air-traffic noise. The objective of this paper is to quantify the level of noise effect for two correlated groups; noise effecting workers and noise effecting environment. The highest values measured in the worst conditions reached 90-100 dB (A).
Cylindrical screw gearing with parallel axes of rotation
M. Bošanský, I. Kožuch, M. Vereš
Res. Agr. Eng., 2007, 53(3):111-115 | DOI: 10.17221/2128-RAE
In the first part the article describes the theory of cylindrical screw gearing and in second part it states an alternative solution of screw gearing with parallel axes of rotation. There are given results of relating correctness of gear meshing and its manufacturing as theoretical problem. Authors present possibilities of screw gearing with parallel axes of rotation in area of agricultural machine application too.
Properties of martensitic overlays
R. Chotěborský, P. Hrabě, M. Müller
Res. Agr. Eng., 2007, 53(3):116-120 | DOI: 10.17221/2126-RAE
The abrasive wear resistance of martensitic overlays is the function of many variables. The hardness is one of the variables. This fact is raised by the possibility of carbidic phases separating from the austenite in the course the overlay layer cooling and by the possibility of the further martensite disintegration and carbidic phases precipitation. The paper is engaged in the hardness and abrasive wear resistance problems of one-layer martensitic overlays.