The high energy properties of the Galactic X-ray binary population, as seen with the Fermi Large Area Telescope

The Fermi Large Area Telescope (Fermi-LAT) is a space instrument which has been in orbit since June 2008, and is sensitive to photons from 30 MeV to approximately 1 TeV. I use the Fermi-LAT data, alongside X-ray and optical data to perform an investigation of the high energy γ-ray properties of the X-ray binaries, stellar systems where either a neutron star or a black hole is in a close orbit with a main sequence star. The complex case of the low mass X-ray binary, V404 Cygni, is looked at; it is determined that there is no evidence for γ-ray emission from this system. The majority of the remaining Galactic X-ray binary population is then surveyed, and evidence for γ-ray emission is found from 5 systems: the high mass X-ray binaries SAX J1324.4-6200, GRO J1008-57, 1A 0535+262 and RX J2030.5+4751 and the low mass X-ray binary GS 1826-238. There are a number of additional systems where spatially coincident γ-ray excesses are identified, however evidence to associate these with their respective X-ray binaries is weak. I examine these systems alongside the X-ray binaries with known γ-ray emission and determine that γ-ray emission in high mass X-ray binaries is highly dependent on orbital phase, and X-ray accretion state so that many undetected systems may be weakly emitting transients. In the case of the low mass systems, I determine that these are nearby sources, and that almost all are known transitional millisecond pulsars. Future observatories such as CTA, SWGO and AMEGO are likely to discover more γ-ray emitting X-ray binaries, and these facilities are discussed

A Comparative Study of the Magnitude, Frequency and Distribution of Intense Rainfall in the United Kingdom

During the 1960s, a study was made of the magnitude, frequency and distribution of intense rainfall over the UK, employing data from more than 120 daily-read rain gauges covering the period 1911 to 1960. Using the same methodology, that study was recently updated utilizing data for the period 1961 to 2006 for the same gauges, or from those nearby. This paper describes the techniques applied to ensure consistency of data and statistical modelling. It presents a comparison of patterns of extreme rainfalls for the two periods and discusses the changes that have taken place. Most noticeably, increases up to 20% have occurred in the north west of the country and in parts of East Anglia. There have also been changes in other areas, including decreases of the same magnitude over central England. The implications of these changes are considered

L’évaluation des SAMI (système d’apprentissage multimédia interactif) : de la théorie à la pratique

Cet article traite de la mise au point d'une stratégie de collecte de données visant à regrouper et à analyser les facteurs sous-jacents au développement d'une interactivité significative dans des situations d'apprentissage médiatisé. Les auteurs ont conçu un modèle adapté d'analyse axée principalement sur une approche qualitative; ils ont utilisé à cette fin des méthodes intégrant la technique de l'entrevue, l'observation directe et l'analyse de protocoles. Celles-ci ont permis de cerner les facteurs perceptifs, transactionnels, cognitifs, pédagogiques et évaluatifs qui peuvent diriger la prise de décision des concepteurs de systèmes d'apprentissage multimédia interactifs. Des mises à l'essai de ce modèle à l'aide de concepteurs issus des milieux de formation scolaire ont indiqué la pertinence et le raffinement des analyses possibles.This article describes the development of a data collection strategy whose aim is to classify and analyse the factors underlying interaction in mediated learning situations. The authors present a model for analysis that is centred principally on a qualitative approach which integrates an interview technique, direct observation, and protocol analysis. These methods were used to describe perceptual, transactional, cognitive, pedagogical, and evaluative factors that could influence decisions made by those who develop interactive multimedia learning systems. Results of trials using this model by developers who work in training and in school contexts show the possible value and the detail that these analyses offer.Este articulo discute la preparacion de una estrategia de recoleccion de datos que busca reagrupar y analizar los factores subyacentes al desarrollo de una interactividad significativa en situaciones de aprendizaje mediatizado. Los autores han creado un modelo adaptado de anâlisis basado principalmente en un enfoque cualitativo, utilizando para es to métodos que integran la técnica de entrevistas, la observation directa y el anâlisis de protocolos. Estos métodos han permitido distinguir los factores perceptuales, transaccionales, cognos-citivos, pedagogicos y evaluativos que pudieran dirigir la toma de decisiones de los disenadores de sistemas de aprendizaje interactivo multimedios. Ensayos de este modelo con disenadores en ambitos de formation y escolar han indicado la pertinencia y el refinamiento del anâlisis posible.Dieser Artikel befasst sich mit der Aufstellung einer Datenerfassungs-strategie, die bezweckt, die Vorrausetzungen fur die Entwicklung einer signifikanten Interaktion in mediatisierten Lernsituationen zusammenzustellen und zu analysieren. Die Verfasser haben ein hauptsâchlich auf qualitatives Vbrgehen hin konzipiertes Untersuchungsmodell entworfen, wobei sie Methoden benùtzten, die das Interview, die direkte Beobachtung und die Protokollanalyse integrieren. Mit diesen Metiioden konnten die Perzeptions-, Transaktions-und Kognitionsfaktoren, sowie die pâdagogischen und die Beurteilungsfaktoren erfasst werden, die fur die Autoren neuer interaktiver Multimedia-Lernsysteme wichtig sind. Das Modell wurde mit Hilfe von von der Bildung oder Schule her kommenden Autoren erprobt; die Relevanz der Untersuchungen wurde dabei bestâtigt

Flexural Creep Comparison to TTS Creep for PP and PP-GF30

Creep testing is one of the most expensive datasets to acquire in both cost ($10k+) and time (2+ months). Dynamic Mechanical Analysis offers a unique opportunity to characterize creep properties of polymers using a technique called Time Temperature Super Positioning (TTSP) in a relatively short period of time. TTSP works by holding either frequency or loading constant at set temperatures for a constant period of time. WLF equations are then used to combine multiple curves from different temperatures into a master curve that can be used to extrapolate out creep performance at designated reference temperatures and save a considerable amount of time if it is comparable to actual creep. Methods were examined to compare neat polypropylene and PP-GF30 long fiber thermoplastic. Long-term flexural creep was also tested at multiple loads and temperatures

P3_2 Thick Skin

We determine the thickness of human skin that would be required to be bulletproof. The kineticenergy of bullets with various calibres are determined and the tensile strength of skin used to find the stopping distance of a bullet inside skin. We find that skin with a thickness of 5-40 cm is required to be bulletproof, dependent on the calibre of the bullet. The limitations of possessing such skin are considered to determine the feasibility of a bulletproof human

P3_5 Fire at Will!

We consider the force produced by Zarya's "Graviton Surge" in the video game Overwatch. Themass required to produce a gravitational field of the necessary strength is found and the conse-quences of utilising such a mass considered. It is shown that the surge must have a mass of 9.4x10^12 kg, but limitations from special relativity make the existence of such a weapon impossible

P3_1 Black Hole formation within Starkiller Base

In the film "Star Wars: The Force Awakens", Starkiller Base pulls an entire star into its fuel chamber to power a laser weapon system. By estimating the dimensions of the fuel chamber, we find that the maximum mass a fuelling star can have before it collapses into a black hole is approximately 7.5 M☉, however, the additional gravitational force produced would make the planet uninhabitable

P3_8 Life with Bulletproof Skin

We consider some of the consequences of possessing skin thick enough to be bulletproof as determined in "P3 2 Thick Skin" [1]. We find that the extra skin would weigh 103 kg however even if this weight could be carried the temperature increase in the body would result in death in as little as 5 hours if not counteracted

P3_4 Honey, I Shrunk the Tank!

In the 2015 film "Ant-Man", a Russian T-34 tank is shrunk down to the size of a keychain,during which its mass remains constant. By estimating the change in inter-atomic spacing, andthe resulting increase in Coulomb repulsion between atomic nuclei, the energy required for thiscompression is found to be approximately 7.08x10^15 J. This an extremely large amount of energy, making the possibility of such a situation infeasible