Tuesdays with Morrie: an old man, a young man, and life\u27s greatest lesson

Albom, Mitch. Tuesdays with Morrie: an old man, a young man, and life\u27s greatest lesson. New York: Bantam, 1997

A social reading of the Old Testament: prophetic approaches to Israel\u27s communal life

Reviewed Book: Brueggemann, Walter. A social reading of the Old Testament: prophetic approaches to Israel\u27s communal life. Minneapolis: Augsburg Fortress, 1994

Ezra-Nehemiah

Reviewed Book: Throntveit, Mark A. Ezra-Nehemiah. Louisville, Ky: Westminster/John Knox Press, 1992. Interpretation, a Bible commentary for teaching and preaching

Mechanochemical synthesis, phase transformation and surface functionalization of metal oxides

Die hochenergetische Kugelvermahlung wurde genutzt um Synthesen, Strukturveränderungen und Oberflächenfunktionalisierungen im Bereich anorganischer Oxide durchzuführen. Die Vermahlung erlaubt den Erhalt nanokristalliner oder amorpher Materialien, sowie die Bildung von Hochdruck- und Hochtemperaturphasen und Defekten. Die entstehenden Phasen können aufgrund dieser Veränderungen als Materialien für Li-Ionen Batterien interessant sein. Vermahlungen wurden für die Verbindungen Li2TiO3, Li4Ti5O12, Mn3O4 und LiMn2O4 durchgeführt. Strukturelle Veränderungen konnten mittels XRD und Rietveldanalysen erfasst werden, die für Titanate durch 6Li Festkörper-NMR ergänzt wurden. Die Oberflächenfunktionalisierung konnte mittels IR Spektroskopie nachgewiesen werden. a-Li2TiO3 und Mn3O4 wurden erstmals mechanochemisch aus monovalenten Oxiden erhalten. Für b-Li2TiO3 und Li4Ti5O12 wurde ein mechanisch induzierter Übergang zu einer kubischen Phase beobachtet. Für LiMn2O4 wurde der Übergang zu einer orthorhombischen und tetragonalen Phase mit Kationenunordnung beobachtet. Der Abbau zu Mn2O3 und einer unbekannten Phase wurde durch in situ Oberflächenfunktionalisierung mit Phenylphosphonsäure im Mahlprozess verhindert. Es konnte gezeigt werden, dass die durch Vermahlung verursachten Linienverbreiterungen nicht nur durch Kristallitgrößeneffekte bedingt sind. Mehrere Strukturmodelle wurden etabliert mit denen die komplexen Veränderungen der Reflexmuster und Linienbreiten in Rietveldverfeinerungen erfasst werden können.High energy ball milling was used to induce syntheses, structure changes and surface functionalizations in the field of inorganic oxide materials. Milling facilitates the formation of nanocrystalline or amorphous materials, as well as the formation of high pressure and high temperature phases and defects. Based on these properties, the products may be interesting as materials for Li-ion batteries. Milling experiments have been conducted using Li2TiO3, Li4Ti5O12, Mn3O4 and LiMn2O4. Structural changes were determined by XRD and Rietveld analysis. In the case of titanates, the studies were complemented by 6Li solid-state NMR spectroscopy. The surface functionalization was proven via IR spectroscopy. For the first time, a-Li2TiO3 and Mn3O4 were synthesized by a mechanochemical route from monovalent oxides. In the case of b-Li2TiO3 and Li4Ti5O12 a mechanical induced transformation to a cubic phase was observed. In the case of LiMn2O4 a transformation to an orthorhombic and tetragonal phase with a cation disorder has been observed. The decomposition to Mn2O3 and an unknown phase was prevented by an in situ surface functionalization with Phenylphosphonic acid in the milling process. It has been shown that the milling induced line broadening is not only caused by crystallite size effects alone. Multiple structure models have been established to accommodate the complex changes of the reflection patterns and line profiles in the Rietveld refinements

Jesus Walked By

John

Towards Robust and Efficient Communications for Urban Air Mobility

For the realization of the future urban air mobility, reliable information exchange based on robust and efficient communication between all airspace participants will be one of the key factors to ensure safe operations. Especially in dense urban scenarios, the direct and fast information exchange between drones based on Drone-to-Drone communications is a promising technology for enabling reliable collision avoidance systems. However, to mitigate collisions and to increase overall reliability, unmanned aircraft still lack a redundant, higher-level safety net to coordinate and monitor traffic, as is common in today's civil aviation. In addition, direct and fast information exchange based on ad hoc communication is needed to cope with the very short reaction times required to avoid collisions and to cope with the the high traffic densities. Therefore, we are developing a \ac{d2d} communication and surveillance system, called DroneCAST, which is specifically tailored to the requirements of a future urban airspace and will be part of a multi-link approach. In this work we discuss challenges and expected safety-critical applications that will have to rely on communications for \ac{uam} and present our communication concept and necessary steps towards DroneCAST. As a first step towards an implementation, we equipped two drones with hardware prototypes of the experimental communication system and performed several flights around the model city to evaluate the performance of the hardware and to demonstrate different applications that will rely on robust and efficient communications

Mechanochemical Induced Structure Transformations in Lithium Titanates: A Detailed PXRD and 6Li MAS NMR Study

Lithium titanates are used in various applications, such as anode materials for lithium intercalation (Li4Ti5O12) or breeding materials in fusion reactors (Li2TiO3). Here, we report the formation of nano-crystalline lithium titanates by a mechanochemical approach and present a deeper insight into their structural characteristics by X-ray diffraction (XRD) and solid-state NMR spectroscopy. The compounds were synthesized in a high-energy planetary ball mill with varying milling parameters and different grinding tools. NaCl type Li2TiO3 (α-Li2TiO3) was formed by dry milling of lithium hydroxide with titania (rutile or anatase) and by a milling induced structure transformation of monoclinic β-Li2TiO3 or spinel type Li4Ti5O12. Heating of mechanochemical prepared α-Li2TiO3 induces a phase transformation to the monoclinic phase similar to hydrothermal reaction products, but a higher thermal stability was observed for the mechanochemical formed product. Microstructure and crystallographic structure were characterized by XRD via Rietveld analysis. Detailed phase analysis shows the formation of the cubic phase from the various educts. A set of two lattice parameters for α-Li2TiO3 was refined, depending on the presence of OH− during the milling process. An average crystallite size of less than 15 nm was observed for the mechanochemical generated products. The local Li environment detected by 6Li NMR revealed Li defects in the form of tetrahedral instead of octahedral site occupation. Subsequent adjustment of the structural model for Rietveld refinement leads to better fits, supporting this interpretatio

Mechanochemical Induced Structure Transformations in Lithium Titanates: A Detailed PXRD and 6Li MAS NMR Study

Lithium titanates are used in various applications, such as anode materials for lithium intercalation (Li4Ti5O12) or breeding materials in fusion reactors (Li2TiO3). Here, we report the formation of nano-crystalline lithium titanates by a mechanochemical approach and present a deeper insight into their structural characteristics by X-ray diffraction (XRD) and solid-state NMR spectroscopy. The compounds were synthesized in a high-energy planetary ball mill with varying milling parameters and different grinding tools. NaCl type Li2TiO3 (α-Li2TiO3) was formed by dry milling of lithium hydroxide with titania (rutile or anatase) and by a milling induced structure transformation of monoclinic β-Li2TiO3 or spinel type Li4Ti5O12. Heating of mechanochemical prepared α-Li2TiO3 induces a phase transformation to the monoclinic phase similar to hydrothermal reaction products, but a higher thermal stability was observed for the mechanochemical formed product. Microstructure and crystallographic structure were characterized by XRD via Rietveld analysis. Detailed phase analysis shows the formation of the cubic phase from the various educts. A set of two lattice parameters for α-Li2TiO3 was refined, depending on the presence of OH− during the milling process. An average crystallite size of less than 15 nm was observed for the mechanochemical generated products. The local Li environment detected by 6Li NMR revealed Li defects in the form of tetrahedral instead of octahedral site occupation. Subsequent adjustment of the structural model for Rietveld refinement leads to better fits, supporting this interpretatio