Schachthöhlen im Bereich der Fränkischen Alb erfuhren während prähistorischer Zeit sehr oft eine Nutzung als Deponierungsorte menschlicher und tierischer Körper sowie anderer Sachfunde. Die Deutung der Einbringungsmotive ist kontrovers, wobei die schlechte Forschungslage bislang keine eindeutigen Belege zuließ. Mit Hilfe dreidimensionaler Dokumentationsverfahren sowie akribischer Fundbergung und -analyse bietet die erst jüngst entdeckte Kirschbaumhöhle in Oberfranken erstmals die Chance, die genauere Ablagerungsgeschichte der Fundhorizonte und die rituellen Handlungsabläufe in Verbindung mit naturwissenschaftlichen Untersuchungen zu rekonstruieren.Les grottes verticales ou gouffres du Jura franconien ont fréquemment été utilisées au cours de la préhistoire pout y déposer des corps humains et animaux ainsi que d’autres matériaux. Les raisons derrière ces dépôts sont mal comprises, et les données sûres manquent, étant donné l’état déplorable des recherches entreprises jusqu’à présent. Mais ceci est en train de changer, grâce à l’enregistrement en trois dimensions et à un relevé méticuleux des données et du mobilier. La grotte de Kirschbaumhöhle en Franconie supérieure, découverte seulement récemment, nous donne pour la première fois l’occasion de reconstruire, en intégrant les résultats obtenus par les sciences naturelles, la séquence détaillée des dépôts, des ensembles et des rituels accomplis dans ces gouffres.Shaft caves (or vertical caves) in the Franconian Alb were frequently used in prehistory for the disposal of human and animal bodies as well as other assemblages. Interpreting the reasons behind such depositions is controversial; unequivocal evidence is hard to come by given the poor state of research conducted to date. But this situation is changing thanks to three-dimensional recording and a meticulous approach to finds recovery. The Kirschbaumhöhle in Upper Franconia, discovered only recently, provides for the first time an opportunity to reconstruct the detailed sequence of deposition of the assemblages and the rituals conducted there by relating them to the results of analyses stemming from the natural sciences.
Components manufactured from brass alloys are widely used in plumbing systems. Traditionally, lead is added to the alloy to improve the machinability. In recent years, the use of lead has been restricted due to health and environmental concerns. New lead-free and low-lead alloys were developed. These alloys usually show a higher cutting force compared to traditional lead-containing brasses. This paper investigates the influence of different rake angles and tool coating on cutting force and chip formation. The two lead-free brass alloys, CW511L and CW724R, are compared to the low-lead brass CW625N.
To improve machinability and in particular chip breakability, brass alloys are usually alloyed with small quantities of lead. Due to environmental and health concerns, the use of lead has been restricted in the last years. As lead-free brass alloys are progressively implemented in the industry, challenges arise due to their differing properties from traditional leaded brass alloys. One of the main challenges in automated continuous cutting processes is the worse chip breakability of lead-free brass alloys leading to longer and tangled chips. Hence, the impact of a high-pressure cutting fluid supply, as well as the impact of a chip-breaking geometry and the combined effect of both, has been investigated at different feeds. The three brass alloys CuZn37 (CW508L), CuZn38As (CW511L), and CuZn42 (CW510L) were studied at varying cutting fluid supply pressure levels and feed rates in a radial cutting operation. Cutting forces were measured, and chips were analyzed. No overall systematic impact of the cutting fluid supply pressure on the cutting forces was observed. In conclusion, increased pressure levels, a chip-breaking geometry, and an increased feed rate enhance the chip breakability of the investigated alloys.
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