Research in Agricultural Engineering, 2017 (vol. 63), issue 1

Evaluation of new biodegradable fluid on the basis of accelerated durability test, FTIR and ICP spectroscopyOriginal Paper

Juraj Tulík, Ľubomir Hujo, Jan Kosiba, Juraj Jablonický, Michela Jánošová

Res. Agr. Eng., 2017, 63(1):1-9 | DOI: 10.17221/6/2015-RAE  

The paper deals with the properties of newly developed synthetic biodegradable fluid in terms of its operational and physico-chemical properties. The evaluated fluid is a new biodegradable fluid MOL Farm UTTO Synt, which belongs to the group of universal gear-hydraulic fluids. At the beginning, the fluid was subjected to accelerated durability test under laboratory conditions, with monitoring its impact on technical conditions of the used hydraulic pump UD 25. After that, the FTIR spectroscopy analysis was performed, with monitoring thermal oxidation, oxidation by acid products, water content and additives depletion. Depletion of additives was also...

Temperature changes of I-V characteristics of photovoltaic cells as a consequence of the Fermi energy level shiftOriginal Paper

Martin Libra, Vladislav Poulek, Pavel Kouřím

Res. Agr. Eng., 2017, 63(1):10-15 | DOI: 10.17221/38/2015-RAE  

Current voltage (I-V) characteristic of illuminated photovoltaic (PV) cell varies with temperature changes. The effect is explained according to the solid state theory. The higher the temperature, the lower the open-circuit voltage and the higher the short-circuit current. This behaviour is explained on the basis of band theory of the solid state physics. The increasing temperature causes a narrowing of the forbidden gap and a shift of the Fermi energy level toward the centre of the forbidden gap. Both these effects lead to a reduction of the potential barrier in the band diagram of the illuminated PN junction, and thus to a decrease of the...

Heating and emission properties of waste biomass in burner furnaceOriginal Paper

Jan Malaťák, Jiří Bradna

Res. Agr. Eng., 2017, 63(1):16-22 | DOI: 10.17221/75/2015-RAE  

Utilization of waste suitable as a fuel for small combustion devices is a very important issue. Therefore, this article analyzes selected waste materials from agriculture and maintenance of municipal vegetation. The pellet samples from composting had very high ash content (22.39 and 36.85% wt.), which resulted in low values of net calorific value (12.66 and 10.24 MJ/kg), but also in bad properties of these samples in high concentration of harmful emission. Other problematic fuel samples were pellets from maintenance of city vegetation and reed canary grass, for which high concentration of carbon monoxide was measured during combustion process. The...

Effect of moisture and region of cut on cassava stalk properties in biomass applicationsOriginal Paper

Nisanath Kaewwinud, Porntep Khokhajaikiat, Apichart Boonma

Res. Agr. Eng., 2017, 63(1):23-28 | DOI: 10.17221/70/2015-RAE  

In an attempt to investigate the potential of using cassava stalk as a biomass material and determine the design requirements for developing a cutting machine, this study aims to investigate physical and mechanical properties of cassavas stalk, under the influence of moisture content and region of cut using statistical techniques. Moisture contents were ranged into three different levels; 54.19, 43.05 and 24.93% wet basis (w.b.) while cutting regions were classified as top (tip of cassava stalk), middle and bottom. Mechanical properties were represented by shearing stress. Physical properties, on the other hand, were represented by length, diameter,...

Investigation of locust bean husk char adsorbability in heavy metal removalOriginal Paper

Ademola Ajayi-Banji, Ayo Ogunlela, Gbolabo Ogunwande

Res. Agr. Eng., 2017, 63(1):29-35 | DOI: 10.17221/44/2015-RAE  

he column adsorption study examines irrigation water treatment prior to its application in order to ensure water-crop-consumer heavy metal transfer reduction to the safe level using locust bean husk char (LBHC) as biosorbent. Char structural pattern was investigated with SEM-EDX machine. Contaminated surface water was introduced simultaneously into the bioreactors containing 100 and 200 g of LBHC and collected after 30, 60, 90 120 and 150 min of detention time. Removal efficiency, isotherm and kinetic sorption model were the evaluation tools for the study. Percent of Cr, Cd and As removal at 150 min retention time were 83.33, 100 and 100%, respectively...

Analysis of production parameters of single-lap bonds adhesive bonded with composites based on aluminium fillerOriginal Paper

Miroslav Müller

Res. Agr. Eng., 2017, 63(1):36-44 | DOI: 10.17221/82/2015-RAE  

In the area of bonding of sheets of metals, mainly in construction of transport and agricultural machines, single-lap bonds are used. In manufacturing corporations focused on bonding of the metal sheets the technologies such as riveting, welding and adhesive bonding are particularly used. These methods are frequently combined. The aim of the research was the evaluation of lap length of alloy AlCu4Mg adhesively bonded using two component epoxy adhesive, which is commonly used in construction of machines and its modification based in addition of filler in form of aluminium microparticles. The secondary aim of the research was to ascertain the influence...