Research in Agricultural Engineering, 2012 (vol. 58), issue 2
Effect of rapeseed methyl ester on fuel consumption and engine power
M. Pexa, K. Kubín
Res. Agr. Eng., 2012, 58(2):37-45 | DOI: 10.17221/41/2011-RAE 
This paper describes the effect of a mixture of rapeseed methyl ester and diesel oil on fuel consumption and power parameters of tractor engine. The hydraulic dynamometer was used to load the engine of Zetor Forterra 8641 tractor over rear power take-off. The measured tractor is almost new with less than 100 h worked. The measurements were realized for several ratios of diesel oil and rapeseed methyl ester (from pure diesel to pure rapeseed methyl ester). The engine was loaded by the dynamometer in several working points which were predefined by engine speed and its torque. The fuel consumption was measured by the flow meter in each of these points....
Linseed harvests parameters depending on the state of cutting mechanism
J. Souček, D. Blažej
Res. Agr. Eng., 2012, 58(2):46-49 | DOI: 10.17221/36/2011-RAE
The operating and economical parameters of agricultural products harvesting are important aspects from production costs point of view. Profitability of the crops depends on quantity and quality of end products and efficiency of growing and harvesting operations. In case of linseeds harvesting by combine harvester statistically important impact of cutting mechanisms state on energy, exploitation and economical parameters was determined.
Assessment of energy use pattern for tomato production in Iran: A case study from the Marand region
M.R. Jadidi, M.S. Sabuni, M. Homayounifar, A. Mohammadi
Res. Agr. Eng., 2012, 58(2):50-56 | DOI: 10.17221/32/2010-RAE
The aim of the contribution was to determine energy consumption of input and output used in tomato production and to optimize the energy inputs in the Marand region, Iran. The study also sought to analyse the effect of farm size on energy use and input costs based on tomatoes production and to reveal the relationship between energy inputs and yield by developing mathematical models. Questions about energy management present very interesting and actual topic in this time. The results revealed that tomato production consumed a total of 65,238.9 MJ/ha of which fertilizers were 50.98% followed by water for irrigation (20.67%). Output-input energy and energy...
Analysis of rock mass borehole temperatures with vertical heat exchanger
R. Adamovský, L. Mašek, P. Neuberger
Res. Agr. Eng., 2012, 58(2):57-65 | DOI: 10.17221/43/2011-RAE
The goal of the article is to analyze the distribution and changes of temperatures in boreholes with the rock mass/fluid tubular heat exchangers used as an energy source for the heat pump. It also aims at documenting changes of temperatures in the rock mass during stagnation and heat extraction, and to compare the temperatures in the active and referential borehole. The testing results showed that temperatures of the rock mass reached a minimal value of 1.3°C at depths of 9 m and 20 m with maximal heat extraction corresponding to minimal air temperatures. The temperatures of the rock mass increased near the end of the heating season to values which...
Influence of moisture content and loading orientation on some mechanical properties of Mucuna flagellipes nut
N.A. Aviara, O.A. Onuh, S.E. Ehiabhi
Res. Agr. Eng., 2012, 58(2):66-72 | DOI: 10.17221/12/2011-RAE
The effects of moisture content and loading orientation on some strength properties of Mucuna flagellipes nut namely, bioyield, yield and rupture points; bioyield, compressive and rupture strengths; and moduli of elasticity, resilience, toughness and stiffness were determined at lateral and longitudinal axial loading, using a Testometric Universal Testing Machine (UTM). In the moisture range of 3.38-10.7% (d.b.), bioyield, yield and rupture points of the nut decreased from 1,137 to 755 N, 1,157 to 790 N and 685 to 365 N, respectively, when loading was on the lateral axis, and increased from 1,090 to 1,888 N, 1,092 to 1,918 N and 420 to 1,215...
Modeling some drying characteristics of garlic sheets under semi fluidized and fluidized bed conditions
R. Amiri Chayjan, K. Salari, B. Shadidi
Res. Agr. Eng., 2012, 58(2):73-82 | DOI: 10.17221/42/2011-RAE
Thin layer drying properties of high moisture garlic sheets under semi fluidized and fluidized bed conditions with high initial moisture content (about 154.26% d.b.) were studied. Air temperatures of 50, 60, 70 and 80°C were applied to garlic samples. Among the applied models, Page model was the best to predict the thin layer drying behavior of garlic sheets. Using this model, correlation coefficient (R2) was high for all drying cases. The computed values of Deff were between 3.38 × 10-10 and 2.54 × 10-9 m2/s during the falling rate drying. Values of Deff for...