Middle atmosphere density and models

The 80 to 130 km altitude region is our old ignorosphere, the region of the atmosphere that no one seems to be interested in and yet the critical region for shuttle entry and atmospheric braking. Comparison between the Air Force reference atmosphere and Shuttle Inertial Measurement Units data shows large fluctuations at high latitudes. New data sources are available now, such as the Arecibo and Millstone Hill ionospheric scatter radars. In the 20 to 80 km altitude range there is a reasonable quantity of data on the mean atmosphere, however, infomation on diurnal variability is needed. In the 20 to 80 km altitude range data is needed to identify systematic variations and models for the regions are preliminary. Unpredictable variations are observed: turbulence, storm effects, gravity waves

The gainers and losers from the United Kingdom\u27s university-related migration: A subregional analysis of Graduate Outcomes Survey data

\ua9 2024 The Authors. Population, Space and Place published by John Wiley & Sons Ltd.Against the background of the rise in higher-education participation rates, this paper examines the spatial redistribution of undergraduates across the United Kingdom resulting from moves to and from university. Drawing on the Graduate Outcomes Surveys of 2017/2018 and 2018/2019, address data coded to 53 subregions (SRs) are used to track those enrolled on degree courses by age 20 from domicile to university and workplace 15 months after graduation. The paper begins by examining how university-ward migration serves to concentrate this group geographically and the way in which subsequent job-related moves tend to reinforce this process. Each person is then classified on the basis of their migration trajectories between domicile and workplace, enabling a set of migration accounts to be produced for each SR. Applying cluster analysis to these accounts, a six-way grouping of SRs is used to gauge change between their domicile and workplace populations in both overall numbers and qualitative characteristics, the latter being measured in terms of educational qualifications preuniversity and occupational status 15 months after graduation. These analyses demonstrate how the different types of SRs fare in these exchanges of students/graduates, with more subregions suffering the ‘double whammy’ of losing out in both quantitative and qualitative terms than gaining from this process, with challenging implications for central government\u27s current ‘levelling-up’ agenda

Windé Koroji Ouest (Mali, Second and Third Millennia BCE): The Environmental and Subsistence Evidence

Windé Koroji Ouest is an early agro-pastoral site situated at the eastern periphery of the Inland Niger Delta of Mali, north of the Gandamia and Bandiagara escarpments. This chapter is the first publication of all subsistence and environmental information available concerning this site which was excavated by the senior author in 1992/1993. The presence of domestic millet ca. 2100-1900 BCE is confirmed, as well as sheep during this same period, with cattle attested subsequently (post 1600 BCE). The role of the environment and potential environmental change in the economy of this site is reviewed. It is argued that Windé Koroji Ouest existed within wider, seasonally mobile settlement networks exhibiting a range of flexible subsistence adaptations

The JKind Model Checker

JKind is an open-source industrial model checker developed by Rockwell Collins and the University of Minnesota. JKind uses multiple parallel engines to prove or falsify safety properties of infinite state models. It is portable, easy to install, performance competitive with other state-of-the-art model checkers, and has features designed to improve the results presented to users: inductive validity cores for proofs and counterexample smoothing for test-case generation. It serves as the back-end for various industrial applications.Comment: CAV 201

Probing vibrational modes in silica glass using inelastic neutron scattering with mass contrast

The effective vibrational density of states (VDOS) has been derived from inelastic neutron-scattering data, for isotopically substituted Si O 18 2 and Si O 16 2 glasses, to gain information about the relative contribution to the Si and O partial VDOS. This is a necessary point of comparison for vibrational mode analyses of molecular-dynamics models. The mass contrast has led to a measurable shift between vibrational mode frequencies in the effective VDOS of Si O 18 2 and Si O 16 2, which is well reproduced in an ab initio simulation. The vibrational band centered at 100.2 meV is confirmed to have significantly lower contribution from the oxygen partial VDOS, than the higher (150.3 and 135.8 meV) and lower energy bands (53.3 meV)

Can we see pulsars around Sgr A*? - The latest searches with the Effelsberg telescope

Radio pulsars in relativistic binary systems are unique tools to study the curved space-time around massive compact objects. The discovery of a pulsar closely orbiting the super-massive black hole at the centre of our Galaxy, Sgr A*, would provide a superb test-bed for gravitational physics. To date, the absence of any radio pulsar discoveries within a few arc minutes of Sgr A* has been explained by one principal factor: extreme scattering of radio waves caused by inhomogeneities in the ionized component of the interstellar medium in the central 100 pc around Sgr A*. Scattering, which causes temporal broadening of pulses, can only be mitigated by observing at higher frequencies. Here we describe recent searches of the Galactic centre region performed at a frequency of 18.95 GHz with the Effelsberg radio telescope.Comment: 3 pages, 2 figures, Proceedings of IAUS 291 "Neutron Stars and Pulsars: Challenges and Opportunities after 80 years", 201

Transient Analysis of X-34 Pressurization System

Two transient operational modes of the X-34 pressurization system were analyzed using the ROCket Engine Transition Simulation (ROCETS) program. The first operational mode considers the normal operation. For the engine burn period, the required helium mass and pressure of each propellant tank were calculated. In the second case, the possibility of failure of the pressurization system solenoid valves, its consequence on the over-pressurization, and simultaneous operation of pressurization and vent/relief systems were evaluated

Microwave Gaseous Discharges

Contains reports on three research projects

Microwave Gaseous Discharges

Contains reports on two research projects