Results for 'titan'

1. Leonard Susskind
2. Andre Cabannes

General Relativity

Leonard Susskind (Author) Leonard Susskind has been the Felix Bloch Professor in Theoretical Physics at Stanford University since 1978, and his online lectures are viewed all around the world. One of the fathers of string theory, he is the author of The Black Hole War and The Cosmic Landscape. Andre Cabannes (Author) André Cabannes taught mathematics at the Massachusetts Institute of Technology and translated the Theoretical Minimum series into French. He lives in France.

Thermodynamic Mechanism of Cryogenic Air Minimum Quantity Lubrication Grinding

The achievement of high-efficiency and precise grinding of difficult-to-cut metals-like titanium alloys-is essential in the aerospace industry. However, the process often results in thermal damage to the workpiece surface, posing a significant technical challenge. While minimum quantity lubrication (MQL) has been used to aid titanium alloy grinding, its effectiveness is limited by insufficient heat dissipation and lubrication. As an alternative to normal temperature air for carrying micro-lubricants, Cryogenic air has shown promise in improving oil film heat transfer and lubrication performance in the grinding zone, thus reducing workpiece surface thermal damage. The experimental state of the technology demands more comprehensive studies on its effectiveness and on the underlying mechanisms. Thermodynamic Mechanism of Cryogenic Air Minimum Quantity Lubrication Grinding addresses these challenges by providing a theoretical framework for understanding and optimizing cryogenic air minimum quantity lubrication in grinding processes, particularly for titanium alloys. It explores the physical characteristics of lubricants under cryogenic conditions, the influence of low temperatures on atomization effects, droplet formation dynamics, and heat transfer mechanisms within the grinding zone. By establishing quantitative relationships between cryogenic air parameters and lubricant properties, the book lays a foundation for enhancing the cooling lubrication mechanism of cryogenic air MQL in grinding processes. Researchers, scholars, and graduate students in universities and research institutes focusing on machining will find this book invaluable, as it goes beyond the theoretical insights into practical solutions to enhance grinding efficiency and reduce thermal damage.

Thermodynamic Mechanism of Cryogenic Air Minimum Quantity Lubrication Grinding

The achievement of high-efficiency and precise grinding of difficult-to-cut metals-like titanium alloys-is essential in the aerospace industry. However, the process often results in thermal damage to the workpiece surface, posing a significant technical challenge. While minimum quantity lubrication (MQL) has been used to aid titanium alloy grinding, its effectiveness is limited by insufficient heat dissipation and lubrication. As an alternative to normal temperature air for carrying micro-lubricants, Cryogenic air has shown promise in improving oil film heat transfer and lubrication performance in the grinding zone, thus reducing workpiece surface thermal damage. The experimental state of the technology demands more comprehensive studies on its effectiveness and on the underlying mechanisms. Thermodynamic Mechanism of Cryogenic Air Minimum Quantity Lubrication Grinding addresses these challenges by providing a theoretical framework for understanding and optimizing cryogenic air minimum quantity lubrication in grinding processes, particularly for titanium alloys. It explores the physical characteristics of lubricants under cryogenic conditions, the influence of low temperatures on atomization effects, droplet formation dynamics, and heat transfer mechanisms within the grinding zone. By establishing quantitative relationships between cryogenic air parameters and lubricant properties, the book lays a foundation for enhancing the cooling lubrication mechanism of cryogenic air MQL in grinding processes. Researchers, scholars, and graduate students in universities and research institutes focusing on machining will find this book invaluable, as it goes beyond the theoretical insights into practical solutions to enhance grinding efficiency and reduce thermal damage.

1. Ouahiba , Ouadah

Les aluminures de Titane pour l'aéronautique

L'objectif est d'étudier l'influence des défauts sur le comportement des alliages à base de TiAl dans l'optique de leur intégration dans les moteurs aéronautiques et automobiles. En effet, l'addition des impuretés peut améliorer la résistance de ces intermétalliques à chaud. Leurs propriétés, comme la structure atomique, l'adhésion, la composition, ainsi que la nature des liaisons interfaciales, peuvent dépendre des caractéristiques des interfaces. L'analyse des propriétés fondamentales de l'interface des phases binaires gamma/alpha 2 des aluminures de titane en présence des défauts ponctuelles permet d'accéder à ces caractéristiques en utilisant la théorie de la fonctionnelle de la densité (DFT) avec l'approximation du gradient généralisé qui est exacte pour examiner le comportement de ces intermétalliques, y compris les propriétés mécaniques (les énergies de clivage), la géométrie de la structure atomique, et la structure électronique (la nature des liaisons). Les résultats de ce travail montrent que la substitution et/ou l'insertion des solutés reste une solution efficace pour l'amélioration du comportement mécanique des alliages à base de TiAl.