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Aufsatz
Comparative investigation of two-dimensional imaging methods and X-ray tomography in the characterization of microstructure
(2017-10-02)
The microstructural features of three different materials have been quantified by means of 2D image analysis and X-ray micro-computer tomography (CT) and the results were compared to determine the reliability of the 2D analysis in the material characterization. The 3D quantification of shrinkage pores and Fe-rich inclusions of an Al-Si-Cu alloy by X-ray tomography was compared with the statistical analysis of the 2D metallographic pictures and a significant difference in the results was found due to the complex ...
Masterarbeit
Burkina Faso Under the Presidency of Thomas Sankara – A Post-Developmental State ?
(2023-05)
Thomas Sankara, one of the most celebrated African idols, was president of Burkina Faso from 1983 until his assassination in 1987. The politics he realized with his government were vanguard in more than one regard: The country’s feminist politics queried patriarchy by promoting equal rights and duties for women and men in several different domains; along with the country’s citizens, migrants could participate in policy-making and thereby shape politics; redistribution was made a political goal aspiring to overcome ...
Aufsatz
Ti6Al4V lattice structures manufactured by electron beam powder bed fusion - Microstructural and mechanical characterization based on advanced in situ techniques
(2022-12-17)
Powder bed fusion (PBF) processes enable the manufacturing of complex components in a time- and cost-efficient manner. Especially lattice structures are currently focused since they show varying mechanical properties, including different deformation and damage behaviors, which can be used to locally tailor the mechanical behavior. However, the present process-structure-property relationships are highly complex and have to be understood in detail in order to enable an implementation of PBF manufactured lattice structures ...
Aufsatz
On the influence of build orientation on properties of friction stir welded AleSi10Mg parts produced by selective laser melting
(2021-04-06)
Welding and joining of components processed by additive manufacturing (AM) to other AM as well as conventionally produced components is of high importance for industry as this allows to combine advantages of either technique and to produce large-scale structures, respectively. One of the key influencing factors with respect to weldability and mechanical properties of AM components was found to be the inherent microstructural anisotropy of these components. In present work, the precipitation-hardenable Al–Si10Mg was ...
Aufsatz
Effect of Grain Statistics on Micromechanical Modeling: The Example of Additively Manufactured Materials Examined by Electron Backscatter Diffraction
(2020-02-21)
Micromechanical modeling is one of the prominent numerical tools for the prediction of mechanical properties and the understanding of deformation mechanisms of metals. As input parameters, it uses data obtained from microstructure characterization techniques, among which the electron backscatter diffraction (EBSD) technique allows us to understand the nature of microstructural features, that are usually described by statistics. Because of these advantages, the EBSD dataset is widely used for synthetic microstructure ...
Aufsatz
Effect of Tool Temperature on Mechanical Properties and Microstructure of Thermo-Mechanically Processed AA6082 and AA7075 Aluminum Alloys
(2020-06-08)
The present work focuses on the effect of thermo-mechanical processing on the mechanical properties and microstructural evolution of AA6082 and AA7075 aluminum alloys using a novel forming process, i. e. integrating solution heat treatment, hot forming and tool quenching. Different tool temperatures ranging from 24 °C to 350 °C were applied to investigate their influence on mechanical strength and ductility. By using various tool temperatures, this study aims to provide insights needed for tailoring the mechanical ...
Dissertation
Synthese und Reaktivität eines cyclischen (Alkyl)(amino)carbens mit 1,1'-Ferrocenylen-Rückgrat
(2023-01)
Ziel der vorliegenden Arbeit war es, cyclische (Alkyl)(amino)carbene mit einem 1,1‘ Ferrocenylen-Rückgrat (fcCAACs) darzustellen und zu charakterisieren und somit eine Kombination aus bekanntermaßen jeweils höchst ambiphilen CAACs und N-heterocyclischen Carbenen mit 1,1‘-Ferrocenylen-Rückgrat (fcNHCs) zu schaffen. Durch das fc-Rückgrat sollten die Zielverbindungen eine im Vergleich zu bisher zugänglichen CAACs noch ausgeprägtere Ambiphilie besitzen und somit eine nochmals gesteigerte Reaktivität zeigen, insbesondere ...
Dissertation
Eigenschaften chromatischer Polynome
(2015-11-02)
Die Berechnung des 1912 von Birkhoff eingeführten chromatischen Polynoms eines Graphen stellt bekanntlich ein NP-vollständiges Problem dar. Dieses gilt somit erst recht für die Verallgemeinerung des chromatischen Polynoms zum bivariaten chromatischen Polynom nach Dohmen, Pönitz und Tittmann aus dem Jahre 2003. Eine von Averbouch, Godlin und Makowsky 2008 vorgestellte Rekursionsformel verursacht durch wiederholte Anwendung im Allgemeinen einen exponentiellen Rechenaufwand. Daher war das Ziel der vorliegenden Dissertation, ...
Aufsatz
Plantain mycorrhization with native consortium of arbuscular mycorrhizal fungi (AMF) induce solubilisation of metals (Fe2+ and Al3+) in soil from Azaguié (south-east of Côte d’Ivoire)
(2023-04-28)
New agroecological practices propose to manage soil fertility using soil microorganisms such as arbuscular mycorrhizal fungi (AMF). However, few studies have been conducted on the impact of plantain mycorrhization and metal (Fe²+ and Al³+) solubilisation in soil. This study evaluates the effectiveness of native AMF on plantain growth and metal leaching from soil. Trap plants (maize, sorghum and cowpea) were grown to produce various inoculums. Then, plantains were grown under controlled conditions, with six treatments ...
Video
50 AÑOS HACIENDO, ENSEÑANDO Y COMENTANDO ARQUITECTURA EN EL PERÚ
(2020-10-17)
"No es tarea fácil resumir en el tiempo disponible la amplia y larga vida profesional que he ejercido con Antonio Graña y Eugenio Nicolini. Complica más la tarea, el hecho de que ella haya estado imbricada con una dedicación académica y una actividad periodística también muy exigentes. A ello, tendría que añadir mi incursión en política y la actividad museográfica, todo lo cual he ejercido con una simultaneidad persistente.
Procuraré por tanto mostrar una fracción de los más de 450 proyectos desarrollados por nuestro ...