Research in Agricultural Engineering, 2013 (vol. 59), issue 4
Index of volume 59Index
editors
Res. Agr. Eng., 2013, 59(4):I-II | DOI: 10.17221/7145-RAE 
Selected physical properties of liquid biofuelsOriginal Paper
P. Trávníček, M. Valach, Z. Hlaváčová, J. Mareček, T. Vítěz, P. Junga
Res. Agr. Eng., 2013, 59(4):121-127 | DOI: 10.17221/14/2013-RAE
The goal of this study was the determination of basic physical properties such as density, calorific value and rheological properties of liquid biofuels. Biofuels on the base of bioethanol and rapeseed methyl ester were chosen. Following control samples were selected: diesel oil without admixture of methyl esters and commercially available diesel oils with small amount of methyl ester admixture (6.2 and 6.5%). Dynamic viscosities of individual samples were measured in the range from -10°C to 50°C. Then dependence of shear rate on shear stress was measured at temperatures -10, 0, 20 and 40°C. The most of samples showed the Newtonian behaviour. However,...
Effect of destabilization treatment on microstructure, hardness and abrasive wear of high chromium hardfacingOriginal Paper
R. Chotěborský, P. Hrabě
Res. Agr. Eng., 2013, 59(4):128-135 | DOI: 10.17221/6/2013-RAE
Hardfacing metals are widely used in arc welding and plasma transfer arc technologies and industries. However, application of hardfacing in agriculture is limited due to low toughness after weld depositing. This study was focused on destabilization of high chromium hardfacing metal. The hardfacing was destabilized at 900 and 1,000°C in the different treatment time intervals. Destabilization treatment showed precipitation of secondary carbides leading to partial transformation of austenite to martensite phase in the matrix. The results show that increasing destabilization temperature increased volume of carbide phase in austenitic matrix which affects...
Silage-corn harvesting machinery traffic effects on soil bulk density and water permeabilityOriginal Paper
I. Ahmadi, H. Ghaur
Res. Agr. Eng., 2013, 59(4):136-140 | DOI: 10.17221/2/2013-RAE
Soil compaction caused by machinery traffic affects the growth of agricultural crops and also has environmental effects like soil damage and erosion. Field experiments were conducted to study the effects of repeated silage-corn harvesting machinery traffic on dry soil bulk density and porosity variations at three different sampling depths, moreover average water permeability coefficient of the examined silty clay loam soil was measured using the falling head method of water permeability test. The examined treatments which were applied while harvesting silage-corn with the combination of tractor, chopper and truck were the number of traffic passes and...
Soldering steel sheets using soft soldersOriginal Paper
M. Brožek
Res. Agr. Eng., 2013, 59(4):141-146 | DOI: 10.17221/7/2012-RAE
The paper contains strength tests results of joints soldered using lead and leadless soft solders. For tests lead solders types Sn63Pb37, Sn60Pb40, Pb60Sn40 and Pb48Sn32Bi and leadless soft solders types Sn96Ag4, Sn99Cu1, Sn70Zn30 and Sn96Ag3Cu1 were used. As basic joint material steel sheet of 1.0 mm thickness and zinc-coated steel sheet of 1.0 mm thickness were used. The size of test specimen was 100 × 20 mm. Two sheets were always cleaned and jointed together. For heating the propane-butane plus air flame was used. The tested assemblies were loaded using the universal tensile-strength testing machine until their failure. At the tests the force needed...
Research of overlays influence on ploughshare lifetimeOriginal Paper
P. Hrabě, M. Müller
Res. Agr. Eng., 2013, 59(4):147-152 | DOI: 10.17221/3/2013-RAE
The aim of this study was to research the impact of the overlaying to increase the resistance to the abrasive wear of the ploughshare using three types of welding tubular wire electrodes. These tubular wire electrodes are used to increase the active parts of machines and equipments processing the soil. The experiment was performed on the six ploughshare plough, where the first and last share was without the overlay. Overlaid shares were compared with non-overlaid shares as standards. From evaluation, it is clear that the best overlaying materials are FILARC PZ 6159, OK Tubrodur 14.70 and OK Tubrodur 15.82. The results proved that the wear of the ploughshare...
Reliability of ZigBee transmission in agriculture productionOriginal Paper
I. Mašík
Res. Agr. Eng., 2013, 59(4):153-159 | DOI: 10.17221/15/2013-RAE
Currently, the unlicensed ISM (Industrial Scientific and Medical) band 2.4 GHz has become saturated due many standards used at once. In agricultural production ZigBee has a lot of applications, from wireless sensors networks to complicated automation applications. This paper deals with improving the coexistence properties of ZigBee (IEEE 802.15.4), while keeping compatibility with the basic standard. This paper describes principles and application of forward error correction above the physical layer, consisting of block data interleaver and Hamming code, and also the effect of improvements in coexistence with variously loaded WiFi 802.11g.