Research in Agricultural Engineering, 2015 (vol. 61), issue 3

Analysis of physical, mechanical and chemical properties of seeds and kernels of Jatropha curcasOriginal Paper

M. Müller, Š. Horníčková, P. Hrabě, J. Mařík

Res. Agr. Eng., 2015, 61(3):99-105 | DOI: 10.17221/10/2014-RAE  

The research was performed to examine the physical, mechanical and chemical properties of seeds and kernels of Jatropha curcas. The test parameters were the dimensions of the seeds and kernels, required energy for oil extraction, determination of fatty acids in the oil by gas chromatography method, determination of the iodine value, determination of the acid value, determination of total polyphenols by the Folin & Ciocault reagent and determination of tocopherols and tocotrienols (vitamin E) by High-performance liquid chromatography. It was ascertained that the size of the seed and kernel varies considerably. Pressing of whole seeds needs...

Off-grid photovoltaic system for illuminationOriginal Paper

P. Kouřím, M. Libra, V. Poulek

Res. Agr. Eng., 2015, 61(3):106-110 | DOI: 10.17221/25/2014-RAE  

The off-grid photovoltaic (PV) system with batteries and with the LED light source was constructed and tested in in laboratory conditions. The PV system is used for emergency illumination and it is independent of the electric grid. The PV system is suitable for example in agriculture in store, in horse barn or in outdoors place. Description of the construction and testing is presented in this paper as well as results of the tests. The PV system was self-sufficient during the summer and autumn period till the November 3, 2011. Since November the illumination mode was modified. The illumination intensity was lowered, the discharging speed was decreased.

Influence of the isolation method of the soapstockfatty component on its characteristicsOriginal Paper

Y.I. Prokof'ev, T.N. Poyarkova, A.R. Bykov, A.S. Shestakov, V.A. Kuznetsov, O.G. Androsova

Res. Agr. Eng., 2015, 61(3):111-115 | DOI: 10.17221/20/2014-RAE  

From soapstock, which is a waste product of sunflower oil production, the fatty component was isolated using isopropyl alcohol, toluene, fusel oil and a mixture of common salt and nonionic surfactants. With the help of the Langmuir film balance the molecular areas of isolated fats were found and the degree of hydrophobization in comparison with the original soapstock was evaluated. It was found that the strongest compression of the monolayer is observed when using fusel oil. The surface active properties of emulsifiers, synthesized by alkaline hydrolysis method on the basis of the obtained fat extracts and original soapstock, were studied. These results...

Evaluation of wheat stubble management practices in terms of the fuel consumption and field capacityOriginal Paper

S. Gürsoy, B. Kolay, Ö. Avşar, A. Sessiz

Res. Agr. Eng., 2015, 61(3):116-121 | DOI: 10.17221/77/2013-RAE  

Five wheat stubble management practices i.e. chopping the stubble by the chopper mounted on combine during harvest and transmitting the straw to trailer (SCDF), chopping the stubble by the chopper mounted on combine during harvest and spreading the straw to field surface (SCDS), chopping the stubble on field surface after harvest by chopper mounted on combine and transmitting the straw to trailer (SCAF), leaving the stubble on field surface (SLS) and removing the stubble left on field surface by baling (SSB) and the cutting height of combine header (10 and 20 cm) were evaluated in terms of fuel consumption and field capacity. The result of the studies...

Impact of evaporative cooling preservation on the shelf life of fruits and vegetable in South Western NigeriaOriginal Paper

M.C. Ndukwu, S.I. Manuwa

Res. Agr. Eng., 2015, 61(3):122-128 | DOI: 10.17221/54/2013-RAE  

Maintaining the freshness of vegetables and fruits even for a short period in a tropical environment is difficult. Fresh fruits and vegetables usually deteriorate faster than other products because they increase in respiration while in storage, due to high moisture content and high tropical heat which lead to a number of physical and physiological changes affecting the viability, quality and marketability of the produce. The use of evaporative cooling system showed improvement in the shelf life of fruits and vegetables stored. The stored vegetables in the cooler showed higher moisture and vitamin C content while the withered control has higher ash,...

Experimental research on phytomass suitable for production of biogasOriginal Paper

M. Pastorek, J. Kára, Z. Pastorek

Res. Agr. Eng., 2015, 61(3):129-133 | DOI: 10.17221/74/2013-RAE  

The structure of the dry material plant is made up of a cell tissues system. The walls of the cells are formed by cellulose and lignin, ingredients difficult to biodegrade. Therefore, the aim of the breeders performed a variety of energy plants, providing a high yield of dry matter in the green state. This applies particularly to herbs, grown on agricultural and arable land (for example cereals, maize, sorghum, hemp, amaranthus, mallow, sugar beet, potatoes, fodder crops on arable land, permanent grassland and other). The subject of the experiment was to evaluate selected varieties of maize and sorghum and to determine the suitability of the materials...

Bonding of woodOriginal Paper

M. Brožek

Res. Agr. Eng., 2015, 61(3):134-139 | DOI: 10.17221/8/2014-RAE  

The paper presents the results of strength tests of joints made using six different adhesives destined by their producers for bonding wood. Bonded samples were made from seven sorts of wood commonly growing in the Czech Republic, namely ash, beach, cherry, maple, pine, spruce and walnut. From semi-products (boards, planks, squared timber logs) the test samples of dimensions 25 × 100 mm and 4 mm thickness were cut out in the direction of year rings. Always two samples were bonded together so that their overlap was of 12.5 mm. All these assemblies were loaded using the universal testing machine up to their rupture. The rupture force and the rupture type...