Research in Agricultural Engineering, 2007 (vol. 53), issue 2

Properties of heat briquettes on basis of cotton processing waste

R. Koutný, B. Čechová, P. Hutla, P. Jevič

Res. Agr. Eng., 2007, 53(2):39-46 | DOI: 10.17221/2119-RAE  

Cotton dust is a waste produced in the cotton spinning mill. This matter in mixture with grain straw and additive of brown coal was used for heat briquettes production. Mechanical properties, energy and emission parameters were investigated during their incineration. The blended briquettes and those with coal additive have better use properties as compared with briquettes produced from pure cotton dust.

Measuring of pulling resistance in machinery with passive working organs

J. Musil, J. Červinka

Res. Agr. Eng., 2007, 53(2):47-53 | DOI: 10.17221/2121-RAE  

A determination of the total pulling resistance of machinery is important in light of its dimensioning as well in light of energy requirements of processed operation. There are several methods to determine it. They can be divided to analytical methods (Goryachkin) and to methods of measurement in field-laboratory conditions using different kinds of force sensors. The most frequently used type is a sensor on the base of tensiometer, which was used during our work. Measured pulling resistance at three working speeds and at ranges of used depths of soil processing 82-122 mm was 9.6-17.4 kN with variation coefficient up to 10%. This measure has proved...

Geometric displacement volume and flow in the phase of a two-phase hydraulic converter

J. Turza, Z. Tkáč, M. Gullerová

Res. Agr. Eng., 2007, 53(2):54-66 | DOI: 10.17221/2122-RAE  

The paper researches the possibilities to replace the parallel flow hydraulic mechanisms in agricultural machinery with hydraulic units with fluid alternating flow as they provide more efficient operation due to their output alternating motion. The method being presented analyses how the geometric displacement volume in the fluid alternating piston converter is created. This is basically achieved by adding or omitting elements in the phase which consequently reduces the quantity of converter types being manufactured.

Technological and constructional aspects affecting bonded joints

M. Müller, R. Chotěborský, J. Krmela

Res. Agr. Eng., 2007, 53(2):67-74 | DOI: 10.17221/2120-RAE  

Adhesive bonding is one of many materials connecting methods. In the last ten years periods the bonding technology noted a boom almost in all industrial branches. The use of bonding technology in the engineering and repairing industry brings considerable savings. Saving in costs, in critical metallic materials and in time are reached and the decrease of the joint weight, too. Therefore the bonding technology pertains to the modern jointing methods even though it is a very old technique. The adhesive bonding technology is influenced by a number of factors which affect the adhesive bond strength. Correcting coefficients have to be considered in construction...

Changes of cellular structure of potato tuber parenchyma tissues during storage

M. Gancarz, K. Konstankiewicz

Res. Agr. Eng., 2007, 53(2):75-78 | DOI: 10.17221/2118-RAE  

The presented work is continuation of researches on cellular structure of potato tuber parenchyma tissue. It concerns changes of the potato tuber cellular structure parameters during storage. Tubers of two varieties: Andromeda and Pasat were tested, 5 tubers for each variety and storage period. Cylindrical samples 10 mm in diameter and 1 mm thick were taken out of two types of tissues - potato pith and internal parenchyma from each tuber. Images of the tissues in natural state were taken with optical confocal microscope. Technique elaborated earlier by the author was used to obtain images containing number of cells sufficient for statistical analysis....