Sökning: "crater"
Visar resultat 11 - 15 av 47 avhandlingar innehållade ordet crater.
11. Nanostructures Studied by Atomic Force Microscopy : Ion Tracks and Nanotextured Films
Sammanfattning : The work presented in this thesis concernes two sorts of nanostructures: energetic-ion-impact-induced surface tracks and gas-deposited WO3 nanoparticles. Our aims to characterise these nanostuctures and understand the physical principles behind their formation are of general interests for basic science as well as of the field of nanotechnology. LÄS MER
12. Inclusion Characteristics and Their Link to Tool wear in Metal Cutting of Clean Steels Suitable for Automotive Applications
Sammanfattning : This thesis covers some aspects of hard part turning of carburised steels using a poly‑crystalline cubic boron nitride (PCBN) cutting tool during fine machining. The emphasis is on the influence of the steel cleanliness and the characteristics of non‑metallic inclusions in the workpiece on the active wear mechanisms of the cutting tool. LÄS MER
13. Geochronology of impact structures - constraining syn- and post-impact processes using the 40Ar/39Ar and U-Pb techniques
Sammanfattning : The discovery, at the beginning of the 20th century, that elements can transform into other elements, due to the spontaneous decay of an instable to a stable atomic nuclei, gave rise to a powerful source for age information in many fields of earth science. For impact structures, it is crucial to establish well-defined and precise ages in order to understand how impact events affect the Earth’s geo and biosphere and also with regard to possible future events that can have devastating effects on our civilization. LÄS MER
14. Terrestrial consequences of hypervelocity impact – shock metamorphism, shock barometry, and newly discovered impact structures
Sammanfattning : Impact cratering was once considered a rare geological process of no, or little, importance to the evolution of the Solar System and planet Earth. After more than 50 years of space exploration and the discovery of numerous (~190 as of October 2016) impact structures on Earth, this view has changed, and it is now clear that impact craters are in fact one of the most common morphological features on solid bodies in the Solar System. LÄS MER
15. Microstructure of a cubic boron nitride tool material and its degradation during hard turning operations
Sammanfattning : Abstract. Polycrystalline cubic boron nitride (PCBN) materials are widely used in turning operations of hardened steels due to their beneficial mechanical properties like maintained high hardness at elevated temperatures, adequate toughness and for being more chemically stable towards iron compared to diamond at temperatures typical for turning operations. LÄS MER
