Template-Type: ReDIF-Article 1.0 Author-Name: J. Blahovec Author-Workplace-Name: Technical Faculty, Czech University of Agriculture in Prague, Prague, Czech Republic Title: Impact induced mechanical damage of Agria potato tubers Abstract: Potato variety Agria was cultivated in different fertilisation and/or irrigation regimes. Tuber damage after impact was studied two months after the harvest with aim to find some relation between the regime of cultivation and impact test tuber damage. It was found that tuber cracking and/or crushing belongs to the most frequent mechanisms of damage masking usual bruising in many cases. Most severe tuber cracking was observed for cultivation with irrigation and classical methods of fertilisation. On the other hand, bruising was most frequent in case without any irrigation and fertilisation and in cases used for fertilisation the pig slurry. In every cultivation regime the bruising was more pronounced in narrower tuber side in comparison to the wider flat side. Keywords: potato, density, stem, bud, cultivation regime, impact, bruising, cracking, crushing, irrigation, fertilisation Journal: Research in Agricultural Engineering Pages: 39-43 Volume: 51 Issue: 2 Year: 2005 DOI: 10.17221/4900-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/4900-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200502-0001.txt Handle: RePEc:caa:jnlrae:v:51:y:2005:i:2:id:4900-RAE Template-Type: ReDIF-Article 1.0 Author-Name: P. Kroupa Author-Workplace-Name: Research Institute of Agricultural Engineering, Prague, Czech Republic Author-Name: J. Skalický Author-Workplace-Name: Research Institute of Agricultural Engineering, Prague, Czech Republic Author-Name: P. Kovaříček Author-Workplace-Name: Research Institute of Agricultural Engineering, Prague, Czech Republic Title: Grain aeration in hangar storage by low-pressure ventilators Abstract: In the paper are presented measured values of air output velocity from the stored grain layer in hangar storage within its aeration by low-pressure ventilators. The proper aeration of the stored grain was conducted by three aerating ventilators of which every was individually connected with the "cage" aerating above-ground channel covered by technically woven fabrics. The channel diameter was 400 mm, axial pitch of the aerating channels was 4.5 m. Air output velocity was measured by the vane anemometer AIRFLOW. From the measured values resulted than the air output velocity from the stored grain layer in the hangar storage is insufficient, the used low-pressure ventilators are inconvenient, even lowest air output velocity has not been reached from the stored grain layer, i.e. 0.002 m/s, what is minimum figure determined only for grain conditioning. Keywords: air distribution, aerating ventilator, air output velocity, grain moisture, grain duality Journal: Research in Agricultural Engineering Pages: 44-49 Volume: 51 Issue: 2 Year: 2005 DOI: 10.17221/4901-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/4901-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200502-0002.txt Handle: RePEc:caa:jnlrae:v:51:y:2005:i:2:id:4901-RAE Template-Type: ReDIF-Article 1.0 Author-Name: M. Růžička Author-Workplace-Name: Faculty of Mechanical Engineering, Czech Technical University in Prague, Prague, Czech Republic Author-Name: K. Doubrava Author-Workplace-Name: Faculty of Mechanical Engineering, Czech Technical University in Prague, Prague, Czech Republic Title: Loading regimes and designing helical coiled springs for safe fatigue life Abstract: Springs are loaded by harmonic forces very often. High cycles fatigue damage and failure can be found during its service loading. This paper shortly describes stress concentration factor for helical springs on the inner diameter of the spring wire and its evaluation by using FE Method. These results have been compared with correction functions published in the literature. The fatigue safety factor has been derived for three typical loading regimes of springs. All cases are demonstrated in the Haigh diagram. It has been showed that loading cases with constant operational prestress give lowest safety factor then the proportional or constant middle stress regimes. Keywords: springs, fatigue of materials, loading regimes, safe fatigue life Journal: Research in Agricultural Engineering Pages: 50-55 Volume: 51 Issue: 2 Year: 2005 DOI: 10.17221/4902-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/4902-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200502-0003.txt Handle: RePEc:caa:jnlrae:v:51:y:2005:i:2:id:4902-RAE Template-Type: ReDIF-Article 1.0 Author-Name: I. A. Loukanov Author-Workplace-Name: Department of Applied Mathematics and Informatics, Masaryk University, Brno, Author-Name: J. Uziak Author-Workplace-Name: Department of Applied Mathematics and Informatics, Masaryk University, Brno, Author-Name: J. Michálek Author-Workplace-Name: Czech Republic Title: Draught requirements of enamel coated animal drawn mouldboard plough Abstract: The power requirement of tillage implements is an important design consideration particularly for animal-drawn implements where the power is limited. The paper presents the possibility of reduction in the draught requirements of animal-drawn mouldboard plough by using enamel coating on the soil-engaged components such as the mouldboard, share and the landside. Trials were conducted to compare enamel-coated Maun Series single mouldboard plough (manufactured by Zimplow Limited, Bulawayo,Zimbabwe) with similar uncoated plough, both animal-drawn, under comparable working conditions. Experiments were done at 25% and 32% d.b. soil moisture content on a red clay soil inZimbabwe. The parameters measured in evaluating the draught performance of both ploughs were the tractive effort (pull), speed of ploughing, depth and width of ploughing, and soil conditions (i.e. soil moisture content, soil bulk density and soil penetration resistance). It was found that for similar working conditions the enamel coating reduced the specific draught by 20 to 26% depending upon soil moisture content. Keywords: enamel coating, uncoated plough, enamel-coated plough, actual draught and specific draught Journal: Research in Agricultural Engineering Pages: 56-62 Volume: 51 Issue: 2 Year: 2005 DOI: 10.17221/4903-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/4903-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200502-0004.txt Handle: RePEc:caa:jnlrae:v:51:y:2005:i:2:id:4903-RAE Template-Type: ReDIF-Article 1.0 Author-Name: L. Ševčík Author-Workplace-Name: Faculty of Mechanical Engineering, Technical University in Liberec, Liberec, Czech Republic Title: Facilities of optimization of car parts in cad system pro/engineer Abstract: New methods covered in this contribution describe the behavior of modeling algorithms that can be added to the parts and their assembly in the input data dependents. These input conditions could be of various types - dimensions, forces, moments, temperature and friction. The method includes the setting of requirements, combination of requirements, test of feasibility and test of sensibility. For consideration of user defined conditions of geometric and mass optimization can be made. Behavior modeling is a new programming product, which can stay as a part of CAD systems. Keywords: CAD system, behavior modeling, computer models, machine parts, optimization Journal: Research in Agricultural Engineering Pages: 63-65 Volume: 51 Issue: 2 Year: 2005 DOI: 10.17221/4904-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/4904-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200502-0005.txt Handle: RePEc:caa:jnlrae:v:51:y:2005:i:2:id:4904-RAE Template-Type: ReDIF-Article 1.0 Author-Name: D. Plíštil Author-Workplace-Name: Technical Faculty, Czech University of Agriculture in Prague, Prague, Czech Republic Author-Name: M. Brožek Author-Workplace-Name: Technical Faculty, Czech University of Agriculture in Prague, Prague, Czech Republic Author-Name: J. Malaťák Author-Workplace-Name: Technical Faculty, Czech University of Agriculture in Prague, Prague, Czech Republic Author-Name: A. Roy Author-Workplace-Name: Research Institute of Agricultural Engineering, Czech Republic Author-Name: P. Hutla Author-Workplace-Name: Research Institute of Agricultural Engineering, Czech Republic Title: Mechanical characteristics of standard fuel briquettes on biomass basis Abstract: The measuring has proved that the energy herbs can be pressed into the form of compact briquettes. It regards 9 varieties of the energy crops, i.e. coriander, crambe, saphlor, sorrel, sorghum, reed canary grass, knotweed, barley straw and rapeseed straw. These energy crops are disintegrated by the grinding mill ŠV 15 (manufacturer Stoza, Ltd.) before the pressing. The fraction size is given by the mesh size of circular cross section of diameter 15 mm. All the crops have constant moisture content during the measuring and uniform diameter 65 mm of the resulting briquettes. The biomass moisture ranges from 9 to 11%. The pressing is conducted by the briquette press HLS 50 (manufacturer Briklis, Ltd.). The measuring results have shown the highest volume weight in following energy herbs: coriander, saphlor, rapeseed straw, sorghum, sorrel and knotweed. The lowest volume weight was found in these crops: reed canary grass, crambe and barley straw. The measuring proved that the highest force for the briquette disintegration is necessary for knotweed, saphlor, sorrel, sorghum and coriander. The lowest force for the briquette disintegration needs the reed canary grass, barley and rapeseed straw and crambe. Crambe contains a high level of oil in its seeds and this fact causes difficulties during their pressing as good mechanical parameters regards, thus they cannot be pressed into the briquette form. Keywords: briquetting, energy herbs, briquette mechanical properties, briquette volume weight, force for briquettes disintegration Journal: Research in Agricultural Engineering Pages: 66-72 Volume: 51 Issue: 2 Year: 2005 DOI: 10.17221/4905-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/4905-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200502-0006.txt Handle: RePEc:caa:jnlrae:v:51:y:2005:i:2:id:4905-RAE