Template-Type: ReDIF-Article 1.0 Author-Name: J. Blahovec Title: 80 years of Professor Radoš Řezníček Journal: Research in Agricultural Engineering Pages: i Volume: 54 Issue: 2 Year: 2008 DOI: 10.17221/999-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/999-RAE.html File-Format: text/html Handle: RePEc:caa:jnlrae:v:54:y:2008:i:2:id:999-RAE Template-Type: ReDIF-Article 1.0 Author-Name: M. Schreiber Author-Workplace-Name: AGCO GmbH, Product Marketing Manager (MP), Marktoberdorf, Germany Author-Name: H.D. Kutzbach Author-Workplace-Name: University of Hohenheim, Department of Agricultural Engineering, Stuttgart, Germany Title: Influence of soil and tire parameters on traction Abstract: The drawbar pull, travel reduction (slip), and rolling resistance are the main criteria to describe the traction behaviour of off road vehicles. Besides the engine performance, the drawbar pull is influenced by the traction conditions such as soil and the tire parameters. These traction conditions have to be described by a limited number of parameters which can be easily determined. Empirical equations were used to analyse roughly 850 traction curves measured and published by Steinkampf. As a result, the important parameters to describe the traction conditions are three tire parameters (radius, width, inflation pressure) and five soil parameters (soil cover, upper soil strength, lower soil strength, clay content, moisture content). These parameters with relative values between 0 and 100% are used to establish the equations for the traction prediction. Main steps to achieve this goal are the extension of the traction slip equation by a linear term of slip, and the description of this curve by 4 meaningful characteristic coefficients: the x- and y-coordinates of the κ-maximum (σ κmax, κmax), the y-axis intercept ρe, and the gradient of κ at zero slip (κ'(0)). Keywords: tire, traction, wheel-slip Journal: Research in Agricultural Engineering Pages: 43-49 Volume: 54 Issue: 2 Year: 2008 DOI: 10.17221/3105-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/3105-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200802-0002.txt Handle: RePEc:caa:jnlrae:v:54:y:2008:i:2:id:3105-RAE Template-Type: ReDIF-Article 1.0 Author-Name: J. Łukaszuk Author-Workplace-Name: Institute of Agrophysics, Polish Academy of Sciences, Lublin, Poland Author-Name: M. Molenda Author-Workplace-Name: Institute of Agrophysics, Polish Academy of Sciences, Lublin, Poland Author-Name: J. Horabik Author-Workplace-Name: Institute of Agrophysics, Polish Academy of Sciences, Lublin, Poland Author-Name: B. Szot Author-Workplace-Name: Institute of Agrophysics, Polish Academy of Sciences, Lublin, Poland Author-Name: M.D. Montross Author-Workplace-Name: Department of Biosystems and Agricultural Engineering, University of Kentucky, Lexington, USA Title: Airflow resistance of wheat bedding as influenced by the filling method Abstract: A study was conducted to estimate the degree of variability of the airflow resistance in wheat caused by the filling method, compaction of the sample, and airflow direction. Two types of grain chambers were used: a cylindrical column 0.95 m high and 0.196 m in diameter, and a cubical box of 0.35 m side. All factors examined were found to influence considerably the airflow resistance. Gravitational axial filling of the grain column from three heights (0.0, 0.95 and 1.8 m) resulted in the pressure drops of 1.0, 1.3, and 1.5 kPa at the airflow velocity of 0.3 m/s. Consolidation of axially filled samples by vibration resulted in a maximum 2.2 times increase in airflow resistance. The tests with cubical sample showed that in axially filled samples the pressure drop in vertical direction was maximum 1.5 times higher than in horizontal directions. In the case of asymmetrically filled samples, the pressure drop at the airflow velocity of 0.3 m/s in vertical direction Z was found to be 1.3 of that in horizontal direction X and 1.95 times higher than with horizontal direction Y, perpendicular to X. Variations in airflow resistance in values comparable to that found in the present project may be expected in practice. Keywords: airflow resistance, grain, drying, aeration, packing structure Journal: Research in Agricultural Engineering Pages: 50-57 Volume: 54 Issue: 2 Year: 2008 DOI: 10.17221/8/2008-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/8/2008-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200802-0003.txt Handle: RePEc:caa:jnlrae:v:54:y:2008:i:2:id:8-2008-RAE Template-Type: ReDIF-Article 1.0 Author-Name: H.J. Hellebrand Author-Workplace-Name: Department of Technology-Assessment and Substance Cycles, Leibniz-Institute for Agricultural Engineering Potsdam-Bornim (ATB), Potsdam, Germany Author-Name: V. Scholz Author-Workplace-Name: Department of Post Harvest Technology, Leibniz-Institute for Agricultural Engineering Potsdam-Bornim (ATB), Potsdam, Germany Author-Name: J. Kern Author-Workplace-Name: Department of Bioengineering, Leibniz-Institute for Agricultural Engineering Potsdam-Bornim (ATB), Potsdam, Germany Title: Nitrogen conversion and nitrous oxide hot spots in energy crop cultivation Abstract: Since 1999, nitrous oxide (N2O) soil emissions from sites cultivated with energy plants have been measured by gas chromatography and gas flux chambers in experimental fields. The main aim of this study was the nitrogen conversion factor and its variability for sandy soils under climatic conditions of Central Europe. Annual plants (hemp, rape, rye, sorghum, triticale) and perennial plants (grass, perennial rye, poplar, willow) were fertilised with three different levels of nitrogen (150 kg N/ha/year, 75 kg N/ha/year, and none). The annual nitrogen conversion factors were derived from the annual mean differences between the fertilised sites and non-fertilised control sites. The mean nitrogen conversion factor for the non-cultivated soils was lower (perennial crops: 0.4%) than that for the regularly cultivated soils (annual crops: 0.9%). Few times, enhanced N2O emission spots with maxima above 1000 μ2O/m2/h, lasting for several weeks, were observed in the course of measurements. The influence of these local peak emissions on the nitrogen conversion factor is discussed. Keywords: nitrogen fertilisation level, N2O soil flux, cultivated and non-cultivated soils, perennial and annual plants Journal: Research in Agricultural Engineering Pages: 58-67 Volume: 54 Issue: 2 Year: 2008 DOI: 10.17221/1001-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/1001-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200802-0004.txt Handle: RePEc:caa:jnlrae:v:54:y:2008:i:2:id:1001-RAE Template-Type: ReDIF-Article 1.0 Author-Name: S. Umeda Author-Workplace-Name: Department of Architecture and Civil Engineering, Fukuyama University, Fukuyama, Hiroshima, Japan Author-Name: W.-J. Yang Author-Workplace-Name: Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan, USA Title: A study on applications of intersecting flows in water reservoir for improvement of water environment problems Abstract: This paper deals with the applications of intersecting flows for the improvement of water environments in water reservoirs. First, the present authors' research results are summarised for flow characteristics in intersecting channels placed in horizontal or vertical positions. All physical phenomena involved are identified and their mechanisms are explained. Subsequently, appropriate methods are obtained for solving the problems of stratified water and eutrophication in water reservoirs. A novel drainage system is developed and a particle ejection experiment for sediment flushing is investigated utilising a reservoir model with glass beads replacing sands. Flow visualisation and measurements are used in each experiment. The study has concluded that intersecting flows are suitable for solving water environment problems in water reservoirs. Keywords: intersecting flow, water reservoir, water environment problem, drainage system, sediment flushing Journal: Research in Agricultural Engineering Pages: 68-79 Volume: 54 Issue: 2 Year: 2008 DOI: 10.17221/3106-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/3106-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200802-0005.txt Handle: RePEc:caa:jnlrae:v:54:y:2008:i:2:id:3106-RAE Template-Type: ReDIF-Article 1.0 Author-Name: S. Grundas Author-Workplace-Name: Bohdan Dobrzanski Institute of Agrophysics of Polish Academy of Sciences, Lublin, Poland Author-Name: G. Skubisz Author-Workplace-Name: Bohdan Dobrzanski Institute of Agrophysics of Polish Academy of Sciences, Lublin, Poland Title: Physical properties of cereal grain and rape stem Abstract: The paper presents the results of a study on the mechanical properties of cereal grain and of rape stems, conducted within the framework of the continuing long-term cooperation between the Bohdan Dobrzański Institute of Agrophysics, The Polish Academy of Sciences (IA PAS) in Lublin, and the Czech University of Life Sciences (CULS) in Prague, Czech Republic. Within the scope of the mechanical properties of cereal grain, the study showed a significant relation between the physical conditions of kernels of common wheat as determined through X-ray detection, and their mechanical properties determined by means of standard tests used in the mechanics of structural materials and of the tests used in the technology of cereal grain processing. The study on the mechanical properties of rape stems demonstrated inter-variety differences between plants with varied resistance to lodging. The estimation of the variability of the mechanical properties along the length of rape stems showed the existence of a characteristic point located close to the first bifurcation. Significant effects were noted of the density of the canopy expressed in the number of plants per square meter, and of nitrogen fertilisation on the strength characteristics of rape stems obtained on the basis of tests of mechanical properties. At the same time, a relation was proved between the mechanical properties of the stems and absorption of X-rays Keywords: Keywords: wheat grain, rape stem, physical properties, utility value Journal: Research in Agricultural Engineering Pages: 80-90 Volume: 54 Issue: 2 Year: 2008 DOI: 10.17221/3/2008-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/3/2008-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200802-0006.txt Handle: RePEc:caa:jnlrae:v:54:y:2008:i:2:id:3-2008-RAE Template-Type: ReDIF-Article 1.0 Author-Name: J. Dunca Author-Workplace-Name: Slovak University of Agriculture in Nitra, Nitra, Slovak Republic Title: Mechanical properties of cereal stem Abstract: The paper deals with the measurement of the resonance frequencies of wheat stems with special respect to different wheat varieties. For the measurement, the dynamical method of the transverse frequency was used. Formulas were derived for the calculation of the bending toughness of stems. The t-test was used for the evaluation of the strength coefficient in bending for the samples of stems of different wheat varieties. The results can be used for the evaluation of the wheat resistance to lodging. Keywords: wheat stems, resonance frequency, strength coefficient in bending, modulus of elasticity, mechanical properties of stem Journal: Research in Agricultural Engineering Pages: 91-96 Volume: 54 Issue: 2 Year: 2008 DOI: 10.17221/5/2008-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/5/2008-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200802-0007.txt Handle: RePEc:caa:jnlrae:v:54:y:2008:i:2:id:5-2008-RAE Template-Type: ReDIF-Article 1.0 Author-Name: B. Dobrzański Author-Workplace-Name: Polish Academy of Sciences, B. Dobrzański Institute of Agrophysics, Lublin, Poland Author-Name: R. Rybczyński Author-Workplace-Name: Polish Academy of Sciences, B. Dobrzański Institute of Agrophysics, Lublin, Poland Title: Influence of packing method on colour perception improving the appearance of fruits and vegetables Abstract: The appearance of fruits and vegetables has a major influence on the perceived quality. Therefore, colour is one of the most important quality parameters in consumers' preferences. Fruits differently exposed to the sun differ in colour, frequently looking unripe and reach full maturity just on handling or transport, some still green and appearing unripe. Oranges, carrot, red beet, and parsley were used for the study of the quality estimation. Different nets used for the packing of fruits were tested. The measurements of lightness and chromaticity parameters were performed according to L*a*b* system. The red net used for the packing of oranges caused a decrease of the lightness parameter L* for all stages of fruits maturity. However, some unripe and bright oranges, through the use of a red net, looked more mature. The chromaticity parameter a* is the most influential factor affecting the human perception of the fruit colour. The red net improves this parameter significantly, thus unripe yellow oranges become more saturated, changing the perception of colour to the predicted range. The colour is insignificant for the net, however, it is important for the classification and quality assessment by humans. Keywords: orange, carrot, red beet, parsley, quality, L*, a*, b*, nets Journal: Research in Agricultural Engineering Pages: 97-103 Volume: 54 Issue: 2 Year: 2008 DOI: 10.17221/4/2008-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/4/2008-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200802-0008.txt Handle: RePEc:caa:jnlrae:v:54:y:2008:i:2:id:4-2008-RAE Template-Type: ReDIF-Article 1.0 Author-Name: S.O. Nelson Author-Workplace-Name: U.S. Department of Agriculture, Agricultural Research Service, Richard B. Russell Agricultural Research Center, Athens, Georgia, USA Title: Dielectric properties of agricultural products and some applications Abstract: The use of dielectric properties of agricultural products for sensing moisture in grain and seed and their application in radio-frequency and microwave dielectric heating is discussed briefly. Values for the dielectric properties of a number of products, including grain and seed, fruits and vegetables, and poultry products, are presented graphically to show the dependence of these properties on frequency, moisture content, and temperature. The potential for using the dielectric properties to sense quality factors other than moisture content is also considered. Keywords: permittivity, radio frequency, microwave, dielectric constant, loss factor, frequency dependence, moisture content, grain, seed, fruits, vegetables, poultry products Journal: Research in Agricultural Engineering Pages: 104-112 Volume: 54 Issue: 2 Year: 2008 DOI: 10.17221/1000-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/1000-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200802-0009.txt Handle: RePEc:caa:jnlrae:v:54:y:2008:i:2:id:1000-RAE Template-Type: ReDIF-Article 1.0 Author-Name: J. Blahovec Author-Workplace-Name: Faculty of Engineering, Czech University of Life Sciences in Prague, Prague, Czech Republic Title: Dielectric properties of deformed early potatoes Abstract: The permittivity of potato tissue was studied during uniaxial compression of cylindrical specimens prepared from two early varieties. Both the real and the imaginary permitivity components were determined repeatedly during the loading and unloading tests. The analysis of the results obtained shows that small differences exist between the permittivity of the late and early potato varieties. The differences are concentrated mainly at frequencies higher than 1 kHz with a maximum between 10 and 100 kHz. The effect of deformation is concentrated into frequencies between 1 and 100 kHz. The effect of deformation on the permittivity values can be divided into reversible and irreversible parts. The results obtained in the loading/unloading tests give some more information on the proportion of both parts. Keywords: soft plant tissue, conductivity, permittivity, frequency, deformation, reversibility Journal: Research in Agricultural Engineering Pages: 113-122 Volume: 54 Issue: 2 Year: 2008 DOI: 10.17221/3104-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/3104-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200802-0010.txt Handle: RePEc:caa:jnlrae:v:54:y:2008:i:2:id:3104-RAE