Template-Type: ReDIF-Article 1.0 Author-Name: Miroslav Mimra Author-Workplace-Name: Department of Machinery Utilization, Faculty of Engineering, Czech University of Life Sciences Prague, Prague, Czech Republic Author-Name: Miroslav Kavka Author-Workplace-Name: Department of Machinery Utilization, Faculty of Engineering, Czech University of Life Sciences Prague, Prague, Czech Republic Author-Name: František Kumhála Author-Workplace-Name: Department of Agricultural Machines, Faculty of Engineering, Czech University of Life Sciences Prague, Prague, Czech Republic Title: Risk analysis of the business profitability in agricultural companies using combine harvesters Abstract: This article presents the results of entrepreneurial risk analysis in a company providing agricultural services where a group of combine harvesters is used. An economic model was created in order to emulate the operational costs of the combine harvesters using MS Excel. Based on the results of the sensitivity analysis, the key factors were determined. For these factors, the risk of achieving the desired economic results was created subsequently. For the simulated situation, the key factors were activated within the range of ± 10% using a triangular distribution of these values. The result of this analysis showed that the most frequent value of CZK 389,692/year will be achieved with a probability of 49.42%. The overall outcome of the combine harvesters should be profitable. Keywords: economic model, scenarios, profit, machinery utilization, business profitability Journal: Research in Agricultural Engineering Pages: 99-105 Volume: 63 Issue: 3 Year: 2017 DOI: 10.17221/63/2016-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/63/2016-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-201703-0001.txt Handle: RePEc:caa:jnlrae:v:63:y:2017:i:3:id:63-2016-RAE Template-Type: ReDIF-Article 1.0 Author-Name: Miroslav Müller Author-Name: Jiří Kejval Author-Workplace-Name: Department of Material Science and Manufacturing Technology, Faculty of Engineering, Czech University of Life Sciences Prague, Prague Czech Republic Title: Research on wear resistance of poly-component composite materials Abstract: The paper deals with the testing of composite materials based on corundum, silicon carbide and glass. The object of the experiments was a particle polymeric composite, whose continuous phase was in the form of a two-component epoxy resin and a discontinuous phase (reinforcing particles) of corundum, silicon carbide and glass of a specific particle size from 4.5 to 260 µm. The research was focused on the evaluation of abrasive wear resistance and hardness of the tested materials. A considerable improvement of the values obtained at measuring the abrasive wear resistance was reached at hybrid composite materials filled with three different components, when 98% improvement was reached compared to the epoxy resin without the filler. The hardness increased up to 35% by adding the filler. The particle size influenced properties of the polymeric composite as the particles of larger sizes bring a positive influence on the wear resistance and the hardness HBW 10/250/30. Keywords: hardness, mechanical properties, polymeric composite, strength, testing, wear Journal: Research in Agricultural Engineering Pages: 106-114 Volume: 63 Issue: 3 Year: 2017 DOI: 10.17221/79/2015-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/79/2015-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-201703-0002.txt Handle: RePEc:caa:jnlrae:v:63:y:2017:i:3:id:79-2015-RAE Template-Type: ReDIF-Article 1.0 Author-Name: Vladimír Šleger Author-Workplace-Name: Department of Mechanical Engineering, Faculty of Engineering, Czech University of Life Sciences in Prague, Prague, Czech Republic Author-Name: Miroslav Müller Author-Workplace-Name: Department of Material Science and Manufacturing Technology, Faculty of Engineering, Czech University of Life Sciences in Prague, Prague, Czech Republic Author-Name: Martin Pexa Author-Workplace-Name: Department for Quality and Dependability of Machines, Faculty of Engineering, Czech University of Life Sciences in Prague, Prague, Czech Republic Title: Evaluation of properties of elastomer seal for fuel systems exposed to effects of rapeseed methyl ester Abstract: Elastomer seals in fuel systems have to evince required mechanical properties also at exposure to fuels. The aim of the research was to determine an influence of various concentrations of rapeseed methyl ester (RME) on a change of mechanical properties of sealing O-rings made from polyacrylate elastomer (an indication ACM). A permanent deformation - compression set (CS), a tensile strength and an elongation after the exposure to the tested environment for the time 20 months were evaluated within the experiment. A fall of the tensile strength, the elongation and the permanent deformation - compression set CS was proved depending on the type of the fuel. The increased negative influence of various concentrations of RME (20% to 100%) on the tested properties of the sealing O-rings compared with the diesel oil complying with the standard EN 590:2004 was not proved. So a significant negative influence of degradation aspects on the tested properties of the O-rings of the ACM type (polyacrylate elastomer) was not proved. Keywords: biofuels, O-ring, compression set, tensile strength, elongation Journal: Research in Agricultural Engineering Pages: 115-120 Volume: 63 Issue: 3 Year: 2017 DOI: 10.17221/55/2016-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/55/2016-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-201703-0003.txt Handle: RePEc:caa:jnlrae:v:63:y:2017:i:3:id:55-2016-RAE Template-Type: ReDIF-Article 1.0 Author-Name: Darwin Author-Name: Afrizal Fazil Author-Workplace-Name: Department of Agricultural Engineering, Syiah Kuala University, Darussalam, Banda Aceh, Indonesia Author-Name: Muhammad Ilham Author-Workplace-Name: Department of Agricultural Engineering, Syiah Kuala University, Darussalam, Banda Aceh, Indonesia Author-Name: Sarbaini Author-Workplace-Name: Department of Agricultural Engineering, Syiah Kuala University, Darussalam, Banda Aceh, Indonesia Author-Name: Satria Purwanto Author-Workplace-Name: Department of Agricultural Engineering, Syiah Kuala University, Darussalam, Banda Aceh, Indonesia Title: Kinetics on anaerobic co-digestion of bagasse and digested cow manure with short hydraulic retention time Abstract: The anaerobic co-digestion of bagasse with digested cow manure was operated in 3 l semi-continuous reactor under mesophlic temperature at 34 ± 1°C. Short hydraulic retention time and high organic loading rate applied were 10 days and 3.465 kg volatile solids (VS)/m3.day, respectively. Anaerobic co-digestion of bagasse with digested cow manure obtained higher biogas yield (69 ml/g VS) compared with the anaerobic digestion of digested cow manure alone (20.42 ml/g.VS). Kinetic assessment revealed that the maximum specific growth rate, the maximum rate of substrate consumption, half-velocity constant, endogenous decay constant and microbial growth yield obtained were 3.917 day-1, 870.309 mg/mg, 15.09 mg/l , 8.1518 day-1 and 0.0193 mg/mg, respectively. This result indicated that a longer retention time was required to allow the bacterial growth. Keywords: kinetic parameters, high organic loading rate, single stage anaerobic digestion Journal: Research in Agricultural Engineering Pages: 121-127 Volume: 63 Issue: 3 Year: 2017 DOI: 10.17221/18/2016-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/18/2016-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-201703-0004.txt Handle: RePEc:caa:jnlrae:v:63:y:2017:i:3:id:18-2016-RAE Template-Type: ReDIF-Article 1.0 Author-Name: Wynand Jacobus van der Merwe Steyn Author-Workplace-Name: Depertment of Civil Engineering, Faulty of Engineering, Built Environment and IT, University of Pretoria, Lynnwood road, Hatfield, South Africa Title: A novel method for the quantification of interfacial tomato stresses during transportation Abstract: Transportation of tomatoes on farm and market roads causes interfacial stresses of tomatoes due to truck dynamics as affected by road and transportation conditions. These stresses may affect the shelf-life of tomatoes if they are high enough to cause damage to the fruit. This paper describes a novel method for the in situ measurement of the stresses during actual transportation of tomatoes, providing the producer information that can assist in taking decisions regarding the use of alternative routes, maintenance of existing routes or changes in packing to prevent excessive stresses onto tomatoes. The process involves measurement of the stresses using a stress-sensor that is recording the interfacial stresses continuously during transportation. These stresses can be correlated to road conditions (quantified through standard road-roughness statistics) and used to subject tomatoes in laboratory conditions to similar stresses to study shelf-life effects of transportation stresses. The paper focuses on the measurement process and first-order data analysis, and excludes a detailed study on the physiological effects of the measured stresses on tomatoes. Keywords: transportation related stress, shelf-life Journal: Research in Agricultural Engineering Pages: 128-135 Volume: 63 Issue: 3 Year: 2017 DOI: 10.17221/64/2015-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/64/2015-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-201703-0005.txt Handle: RePEc:caa:jnlrae:v:63:y:2017:i:3:id:64-2015-RAE Template-Type: ReDIF-Article 1.0 Author-Name: Kaarel Soots Author-Name: Jüri Olt Author-Workplace-Name: Institute of Technology, Estonian University of Life Sciences, Tartu, Estonia Title: Non-stationary processing centre for small and mediumsized blueberry farms. A Review Abstract: Growing blueberries on exhausted milled peat fields could be a possible solution to decrease carbon dioxide emission from these areas. To operate such crop-giving plantation manually, a lot of manpower is needed. To decrease the manpower, suitable and helpful technical solutions should be introduced. The aim of this article is to investigate different technological aspects of post-harvest processing of blueberries and to study already existing technical solutions. As a result, non-stationary processing centre for small or medium-sized blueberry farms is proposed. The proposed solution allows reducing manpower, lowering production costs and increasing the area used for growing blueberries. Also, it may encourage other farms to start growing blueberries. Keywords: agricultural engineering, berry sorter, bilberry, post-harvest treatment Journal: Research in Agricultural Engineering Pages: 136-144 Volume: 63 Issue: 3 Year: 2017 DOI: 10.17221/42/2015-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/42/2015-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-201703-0006.txt Handle: RePEc:caa:jnlrae:v:63:y:2017:i:3:id:42-2015-RAE