المؤلفون: Sebastian Ramm, Hans Heinrich Voßhenrich, Mario Hasler, Yves Reckleben, Eberhard Hartung

المصدر: Agriculture, Vol 14, Iss 2, p 263 (2024)

مصطلحات موضوعية: corn harvest, corn header, corn stover, flail mower, European corn borer, combine harvester, Agriculture (General), S1-972

الوصف: The European corn borer is a major pest of corn that overwinters in corn stubble and stalks. Shredding these residues disrupts the larvae’s habitat or directly harms them. A corn header has been engineered with a new type of cutting tool on its horizontal choppers, featuring sharp edges and dulled flails, to shred corn stubble near the soil surface. This study investigated the effect of the dulled flails on the shredding intensity of corn stover. Field trials compared flail knives with standard knives for particle size distribution of corn stover and structural integrity of corn stalk segments. Additionally, a common two-step method, which involved a standard knives-equipped corn header followed by tractor-driven flail mowers, was tested. The flail knives reduced the mean particle size by 3.6 mm compared to the standard knives. Subsequent processing with tractor-driven flail mowers, following the corn header using standard knives, led to a reduction in mean particle size by 11.8 mm. It also further reduced the number of incompletely destroyed stalk segments. However, completely intact internodes were scarce in all methods. Given that flail knives enhance shredding intensity without a second processing step, this concept is concluded to be effective for corn stover shredding.

وصف الملف: electronic resource

العلاقة: https://www.mdpi.com/2077-0472/14/2/263Test; https://doaj.org/toc/2077-0472Test

الوصول الحر: https://doaj.org/article/24455a7ed5db43efb1f754a99626e341Test

المؤلفون: Sebastian Ramm, Mario Hasler, Yves Reckleben, Eberhard Hartung

المصدر: Agriculture, Vol 13, Iss 4, p 833 (2023)

مصطلحات موضوعية: corn harvest, corn header, corn stubble, corn residue, stubble shredding, European corn borer, Agriculture (General), S1-972

الوصف: This study aims to evaluate the efficiency of a new type of corn header equipped with flail knives that shreds corn stubble close to the ground. A field trial was carried out to quantify the influence of the shredding tool design (flail knives, standard knives, horizontal choppers disengaged), harvesting speed (1.5, 3.0, 4.5, 6.0 km/h) and cutting height (approx. 20 cm variation, 4 levels) on the power consumption of the corn header, engine load and fuel consumption of the combine harvester. The regression analyses revealed that modifications of the shredding tool assembly have significant effects on the parameters of the functional relationships. The power consumption of the flail knives configuration was 15 kW/row unit at 6 km/h at the lowest cutting height setting, making it compatible with most current combine harvester models. The additional power demand and fuel consumption that arise when switching to the new shredding tool design (flail knives) show a wide range, depending on the initial situation. Compared to the standard knives at 6 km/h, the additional power consumption was 3.6–5.5 kW/row unit and the additional fuel consumption was 2.6–3.9 L/ha. Compared to the configuration with disengaged horizontal choppers, it was 5.3–6.6 kW/row unit and 3.9–5.1 L/ha, respectively. At 90% engine load the additional power requirement was 1.6–3.1 kW/row unit and the additional fuel consumption was 2.9–5.6 L/ha compared to the standard knives configuration and 2.6–3.6 kW/row unit and 5.6–7.2 L/ha respectively, compared to the configuration with disengaged horizontal choppers.

وصف الملف: electronic resource

العلاقة: https://www.mdpi.com/2077-0472/13/4/833Test; https://doaj.org/toc/2077-0472Test

الوصول الحر: https://doaj.org/article/67a68130afb844cb9404405d1f76bb1dTest

المؤلفون: Philipp G. Grützmacher, Sebastian Rammacher, Dominic Rathmann, Christian Motz, Frank Mücklich, Sebastian Suarez

المصدر: Friction, Vol 7, Iss 6, Pp 637-650 (2019)

مصطلحات موضوعية: dry sliding, microstructural analysis, tribo-oxidation, wear, Mechanical engineering and machinery, TJ1-1570

الوصف: Abstract Understanding the microstructural and tribo-chemical processes during tribological loading is of utmost importance to further improve the tribological behavior of metals. In this study, the friction, wear and tribo-chemical behavior of Ni with different initial microstructures (nanocrystalline, bi-modal, coarse-grained) is investigated under dry sliding conditions. In particular, the interplay be-tween frictional response, microstructural evolution and tribo-oxidation is considered. Friction tests are carried out using ball-on-disk experiments with alumina balls as counter-bodies, varying the load between 1 and 5 N. The microstructural evolution as well as the chemical reactions beneath the samples’ surface is investigated by means of cross-sections. The samples with finer microstructures show a faster run-in and lower maximum values of the coefficient of friction (COF) which can be attributed to higher oxidation kinetics and a higher hardness. It is observed that with increasing sliding cycles, a stable oxide layer is formed. Furthermore, initially coarse-grained samples show grain refinement, whereas initially finer microstructures undergo grain coarsening converging towards the same superficial grain size after 2,000 sliding cycles. Consequently, the experimental evidence supports that, irrespective of the initial microstructure, after a certain deformation almost identical steady-state COF values for all samples are achieved.

وصف الملف: electronic resource

العلاقة: http://link.springer.com/article/10.1007/s40544-019-0259-5Test; https://doaj.org/toc/2223-7690Test; https://doaj.org/toc/2223-7704Test

الوصول الحر: https://doaj.org/article/c57d5c882d9b4ca392faaea2a1131a90Test