Engage D2.10 10th SESAR Innovation Days report

This report describes the tenth edition of the SESAR Innovation Days, which took place as a virtual event between 7th and 10th December 2020

Engage D2.9 9th SESAR Innovation Days report

This report describes the ninth edition of the SESAR Innovation Days, which took place in Athens, Greece, 02 – 06 December 2019

Engage D2.8 8th SESAR Innovation Days report

This report describes the eighth edition of the SESAR Innovation Days, which took place in Salzburg, Austria between 3rd and 7th December 2018

Engage D3.4 Thematic challenges priming report for first workshops

This document describes the process used by the Engage KTN to select the thematic challenges central to the network and how these are being used to define its first set of workshops

Engage D2.11 11th SESAR Innovation Days report

This report describes the eleventh edition of the SESAR Innovation Days, which took place as a virtual event between 7th and 9th December 2021

Dynamics of high-bypass-engine thrust reversal using a variable-pitch fan

The test program demonstrated that successful and rapid forward-to reverse-thrust transients can be performed without any significant engine operational limitations for fan blade pitch changes through either feather pitch or flat pitch. For through-feather-pitch operation with a flight inlet, fan stall problems were encountered, and a fan blade overshoot technique was used to establish reverse thrust

Engage D3.5 Opportunities for innovative ATM research (interim report)

This document reports on the topics and academic disciplines of past Exploratory Research projects, notably SESAR Workpackage E (long-term and innovative research) and SESAR Exploratory Research (ER) with a view of tracing the evolution of research as well as opportunities for future research. This analysis is complemented with relevant activities in Engage, such as the Engage thematic challenges

Engage D2.7 Annual combined thematic workshops progress report

This deliverable reports on the organisation and results obtained from the third and fourth editions of the Engage thematic challenge (TC) workshops held in 2021. Due to the Covid-19 pandemic, the third editions of the TC2 and TC3 workshops, initially scheduled to be held in 2020, were delayed to the beginning of 2021. The TC1 and TC4 workshops reached their third edition in 2021, while TC2 and TC3 closed with the fourth edition. The main lessons learned relate to data availability, collaboration opportunities, machine learning and artificial intelligence methodologies and approaches, and incentives for future ATM implementations

Modeling the momentum distributions of annihilating electron-positron pairs in solids

Measuring the Doppler broadening of the positron annihilation radiation or the angular correlation between the two annihilation gamma quanta reflects the momentum distribution of electrons seen by positrons in the material.Vacancy-type defects in solids localize positrons and the measured spectra are sensitive to the detailed chemical and geometric environments of the defects. However, the measured information is indirect and when using it in defect identification comparisons with theoretically predicted spectra is indispensable. In this article we present a computational scheme for calculating momentum distributions of electron-positron pairs annihilating in solids. Valence electron states and their interaction with ion cores are described using the all-electron projector augmented-wave method, and atomic orbitals are used to describe the core states. We apply our numerical scheme to selected systems and compare three different enhancement (electron-positron correlation) schemes previously used in the calculation of momentum distributions of annihilating electron-positron pairs within the density-functional theory. We show that the use of a state-dependent enhancement scheme leads to better results than a position-dependent enhancement factor in the case of ratios of Doppler spectra between different systems. Further, we demonstrate the applicability of our scheme for studying vacancy-type defects in metals and semiconductors. Especially we study the effect of forces due to a positron localized at a vacancy-type defect on the ionic relaxations.Comment: Submitted to Physical Review B on September 1 2005. Revised manuscript submitted on November 14 200