Research in Agricultural Engineering, 2003 (vol. 49), issue 4
Low frequency electric properties utilization in agriculture and food treatment
Z. Hlaváčová
Res. Agr. Eng., 2003, 49(4):125-136 | DOI: 10.17221/4963-RAE 
Determination of electrical properties is utilized in a wide range of disciplines and industries. A brief compendium of agricultural materials and food electrical properties exploitation is presented in this paper. The measurement of electrical conductivity or resistivity can be utilized at investigation of cell membrane properties on microscopic level. Moreover the electrical conductivity have utilization at the salinity of soils and irrigation water determination. Biological material properties are determined from their leachates too. The conductivity measurement are applied for determination of various characteristics of agricultural materials and...
Evaluation of long term storage of apples by means of fractal analysis
Ľ. Kubík, A. Pavelková, T. Hornyák, P. Kováč, V. Horčin, J. Fúsková
Res. Agr. Eng., 2003, 49(4):137-145 | DOI: 10.17221/4964-RAE
Realization of long-term apple storage requires the most detailed information about the flesh structure and texture, whose quality is contributing by responsible way to the whole quality of the evaluated fruits. The fractal analysis that the fractal dimension of the flesh structure determination is enabling was used. Structure degradation of four apples variants of the variety Idared was evaluated by fractal dimension during long-term storage in standard conditions. The influence of the storage on the fractal dimension was investigated by means of regression dependencies. The dependences express a decrease of the fractal dimension value in the relation...
Thermo-technical properties of floor structures for lying cubicles
J. Lendelová, Š. Pogran
Res. Agr. Eng., 2003, 49(4):146-150 | DOI: 10.17221/4965-RAE
A paper dealing with prevailing floor construction types from a thermo-technical point of view. The accent was put on lying cubicles for cows, the floors must be soft, dry, warm and flexible. Attention was paid to analysis of the thermal resistance and thermal absorptive capacity of selected types of flooring. The greatest thermal comfort depends upon the design of floor structured coating materials. A biological floor accretion layer has a positive thermal influence and softens thermal comfort during the animals lying period. A calculation, estimating values of thermal absorptive capacity, shows that the quality and thickness of the structured layer...
Testing stand for life tests of hydrostatic pumps with a polluted fluid
I. Petranský, M. Bolla
Res. Agr. Eng., 2003, 49(4):151-156 | DOI: 10.17221/4966-RAE
Testing of the lifetime of hydrostatic transmissions can be done on special testing stands. Some testing stands use a pressure valve connected at the outlet of a pump. When using this design of stands, it is important to keep clear the operating fluid by filters and it is not possible to observe the influence of fluid pollution on the lifetime. The article presents a design of an electro-hydraulic testing stand with computer control system for accelerated lifetime tests of hydrostatic pumps under laboratory conditions when using a polluted operating fluid. A pump, which is mechanically connected with a hydrostatic motor, through a clutch, is an interface...
Thermophysical parameters of corn and wheat flour
M. Božiková
Res. Agr. Eng., 2003, 49(4):157-160 | DOI: 10.17221/4967-RAE
This article deals with thermophysical properties of nutritive raw materials particularly of corn and wheat granary mass. It is necessary to know thermophysical performance of granary mass for protection of quality of technological process by processing to final products. Granary mass consist of grains complex of specific kind. It is non uniform material in microscopic and macroscopic structure. There are enacted biophysical and physiological processes. Heat transfer can not be isolated by solid transfer and heat - moisture transfer. It means that specification of granary mass and granary fragments is difficult to determine. We researched thermal properties...
Exploitation of the software product Pro/Mechanica in the agricultural research
J. Bajla, Z. Balogh, M. Božik
Res. Agr. Eng., 2003, 49(4):161-164 | DOI: 10.17221/4968-RAE
The program system Pro/MechaniCa is a specific software product designed for solving of different kinds of technical problems in general engineering. We were looking for usage not only in the engineering but also in the terramechanical area. We realized a simulation loading of the soil with a rigid circular table and after the loading we calculated deformations and stresses under the table using FEM (Finite Element Method). This article shows a specific exploitation program Pro/Mechanica in an unconventional area as well as in the agricultural area.