Research in Agricultural Engineering, 2015 (vol. 61), Special Issue
Mechanical properties of pellets in compressionOriginal Paper
Ľ. Kubík, V. Kažimírová
Res. Agr. Eng., 2015, 61(10):S1-S8 | DOI: 10.17221/17/2015-RAE 
The paper deals with the evaluation of mechanical properties of the cylinder pellet samples. The pellets were made from hay by the granulating machine MGL 200 (Kovonovak) provided by the Department of Production Engineering, Slovak University of Agriculture in Nitra. The pellets were submitted to compressive loading. The compressive loading curves of dependencies of force on strain and force on time were realised by the test stand Andilog Stentor 1000. Certain mechanical parameters were determined, namely the diameter of the sample, length of the sample, force at 10% of strain, force in the first maximum of the force - strain curve, strain in the first...
Recycling of Polyamide from Scrap Tyres as Polymeric CompositesOriginal Paper
M. Müller, J. Žarnovský, R. Drlička
Res. Agr. Eng., 2015, 61(10):S79-S83 | DOI: 10.17221/51/2015-RAE
Rubber granulate, metal waste and textile waste (polyamide fibres) come into the mechanical process of waste tyres recycling. The pollution and degradation processes are problematic in using of secondary raw material. The matrix was in the form of three various adhesives in testing - two-component epoxy adhesives and a polyester adhesive. The filler was in the form of textile waste (polyamide fibres) from the process of tyres recycling containing approximately 10-12% of rubber granulate. The filler was added in app. 15% of weight ratio into the matrix. The aim of the research was to determine a possible utilisation of unsorted textile waste from the...
Monitoring the inner surface of teat cup liners made from different materialsOriginal Paper
R. Gálik, Š. Boďo, L. Staroňová
Res. Agr. Eng., 2015, 61(10):S74-S78 | DOI: 10.17221/50/2015-RAE
The modern milking equipment consists of several rubber parts. Among these rubber parts, the most important is a teat cup liner, which provides direct contact force to teat tissue. Properties of teat cup liners directly affect the technical and technological process of milking, udder health condition and quality of obtained milk. The aim of the study is to specify the inner surface roughness of cup liners made from different materials. Roughness was measured using Surftest-301 Mitutoyo connected to a printer. Teat cup liners were monitored and evaluated at three different locations of the inner surface, every three months in primary production. The...
Influence of material solution of cover shells on stable daylightOriginal Paper
M. Balková, D. Páleš
Res. Agr. Eng., 2015, 61(10):S67-S73 | DOI: 10.17221/47/2015-RAE
The impact of material solution of cover shells on stable daylight. Light is supplied to the stable via a roof skylight, where wired glass is the infill of skylight structure, through open side walls, whereby the influx of light on one side is influenced by the shelter, and through the open gates, which are located in the front walls of the stable were assessed. Measurements of light intensity inside the stable were carried out in two height levels. Simultaneously, measurements were performed outside, on non-shadowed plane. Daylight factor was calculated from the measured values of internal and external comparative illuminance. Resulting values were...
Degradation of animal malodourOriginal Paper
I. Janoško, M. Čery
Res. Agr. Eng., 2015, 61(10):S60-S66 | DOI: 10.17221/35/2015-RAE
Animal waste represents a significant threat to the environment. Degradation of waste from dead animals is in general carried out in specialized facilities (rendering plants) under specific rules and guidelines. In plant proximity, undesirable malodour is usually produced during the combustion process. This odour can be effectively reduced so that it does not negatively affect the environment and society. Degradation of animal waste malodour can be processed in ozonisers, thermal combustion devices or in bio washers. The purpose of this paper is to determine the limits of exhausts that are produced during direct combustion of animal waste malodour....
Analysis of the loading process effect on the tribological node geometry change of agricultural machineOriginal Paper
M. Kučera, V. Malý, M. Kučera
Res. Agr. Eng., 2015, 61(10):S53-S59 | DOI: 10.17221/31/2015-RAE
The effect of loading on the properties of selected sliding pairs has been analysed. The experimental tests were performed using the testing machine Tribotestor M10. The steel 11 600 and all-bronze sleeve of CuSn12 material has been selected as the elements of friction pair. Two oils were selected for lubrication of friction node - the mineral gear oil Madit PP80 and ecological oil Plantohyd 46 S. Chosen friction pairs were tested in three loading regimes (two dynamic processes and one static process). 60 tribological tests have been performed. The weight loss, the change of surface roughness and the absolute change of cylindricity of the friction...
Autonomous control of biaxial tracking photovoltaic systemOriginal Paper
M. Olejár, V. Cviklovič, D. Hrubý, O. Lukáč
Res. Agr. Eng., 2015, 61(10):S48-S52 | DOI: 10.17221/29/2015-RAE
Tracking photovoltaic systems maximize solar energy on the photovoltaic cells surface in order to maximize the energy gain at a given moment. Energy gain is dependent on the accuracy of photovoltaic cells direction, control method and tracking period. The control of tracking systems is based on theoretical calculations of sun position for a specific position in specific time. Designed control algorithm of the biaxial tracking photovoltaic system is able of autonomous navigation directed to the sun without knowing the position. It is based on the sun position sensor. The designed solution increases the solar gain by 33.8% in comparison with stable photovoltaic...
Quality control of aluminium melt in production processOriginal Paper
M. Kotus, E. Jankajová, M. Petrík
Res. Agr. Eng., 2015, 61(10):S43-S47 | DOI: 10.17221/28/2015-RAE
The quality of aluminium alloy in the production process on the chemical composition basis was evaluated. The quality of casting alloy depends on the chemical composition of melt and on the technological process of production process. The basic elements such as Si, Cu, Fe, Mg and Al in melting were evaluated. The obtained data were compared with the guide data referred to in the standard for aluminium alloy.
Possibilities of improving the wheel tractor drive force transmission to soilOriginal Paper
R. Abrahám, R. Majdan, R. Drlička
Res. Agr. Eng., 2015, 61(10):S37-S42 | DOI: 10.17221/26/2015-RAE
The possibility of increasing maximal drawbar pull of tractor working on the soil was evaluated. The increase in drawbar pull occurred due to special wheels mounted on the drive axle. The special wheels were equipped with auto-extensible blades and designed at the Slovak University of Agriculture in Nitra. The main advantage of the special wheels is an automatic extension of steel blades to increase the drawbar pull during a wheel slip and automatic return to the base position to allow the transport of tractor by the route. The testing operation points at the decrease of wheel slip resulted in the increase of drawbar pull. The drawbar pull of tractor...
Assessment of risks in the field of safety, quality and environment in post-harvest lineOriginal Paper
M. Žitňák, K. Kollárová, M. Macák, M. Prístavková, M. Bošanský
Res. Agr. Eng., 2015, 61(10):S26-S36 | DOI: 10.17221/23/2015-RAE
The objective of this work is the evaluation of threats in the field of safety, fire safety, quality and environment in the post-harvest treatment of grain, with an emphasis put on pre-cleaning and drying of grain. The paper describes the technology of pre-cleaning and drying of grain. Risks for individual machines were evaluated using a failure mode and effects analysis (FMEA), which is used to evaluate the threats in terms of fire risk, occupational safety, the effect of machine on the quality of final product, and effect on the environment. We have proposed measures and solutions to eliminate or minimise the consequences of threats. Risk rates are...
Analysis of residual biomass of liquid biofuels using gravimetric method and combustion heatOriginal Paper
J. Chrastina, L. Staroňová, I. Vitázek, M. Pšenka
Res. Agr. Eng., 2015, 61(10):S21-S25 | DOI: 10.17221/22/2015-RAE
The using possibilities of secondary raw materials produced during the liquid biofuels production such as bioethanol and biodiesel, and also those produced during solid fuel production was determined. The study presents combustion of distiller's dried grain with solubles (DDGS) and pressing refuse of rapeseed methyl ester (RME). The combustion was done in gravimetric oven, according to the standards, under the laboratory conditions. Combustion heat of samples was measured with calorimeter IKA C5000. The results show the average combustion heat of 20.91 MJ/kg for DDGS and 18.996 MJ/kg for RME. Results are chronologically presented in tables and figures.
Impact of construction and technological solution of dairy cows housing on production of ammonia and greenhouse gases in winterOriginal Paper
I. Karandušovská, Š. Mihina, M. Bošanský
Res. Agr. Eng., 2015, 61(10):S13-S20 | DOI: 10.17221/21/2015-RAE
The aim of this experiment was to analyze the changes of ammonia production and greenhouse gases in frequent type of stables for dairy cows in winter. Two analyzed stables were situated side by side, one of which is after reconstruction of housing and ventilation technology and the second stable remained in original state. Variances of the mass concentration of gases differed significantly (P < 0.05), and the production of all gases monitored in winter was higher in the original stable. The average ammonia production was 2.45 ± 1.9 mg/m3 in the reconstructed stable, while in the original stable it was 5.1 ± 2.7...
Experimental determination of lethal doses of heat in thermal weed controlOriginal Paper
M. Mojžiš, I. Vitázek, F. Varga, S. Lindák
Res. Agr. Eng., 2015, 61(10):S9-S12 | DOI: 10.17221/20/2015-RAE
Thermal weed control performed by weeders working on physical principles is already commonly used on farms dealing with bioproducts. It helps to reduce strenuous human labour and to effectively control weeds and, to some extent, pests and diseases threatening the crops. It also prevents other weeds from spreading by destroying them in the early growth stage. In addition, development of weeds is inhibited when the soil is not being ploughed. Effective deployment of these machines in practice is currently addressed by experts in the field, as well as the possibility of rational use of heat energy while achieving the maximum effect on weeds. This method...