Attitude motion of a non-attitude-controlled cylindrical satellite

In 1985, two non-attitude-controlled satellites were each placed in a low earth orbit by the Scout Launch Vehicle. The satellites were cylindrical in shape and contained reservoirs of hydrazine fuel. Three-axis magnetometer measurements, telemetered in real time, were used to derive the attitude motion of each satellite. Algorithms are generated to deduce possible orientations (and magnitudes) of each vehicle's angular momentum for each telemetry contact. To resolve ambiguities at each contact, a force model was derived to simulate the significant long-term effects of magnetic, gravity gradient, and aerodynamic torques on the angular momentum of the vehicles. The histories of the orientation and magnitude of the angular momentum are illustrated

The integration of mobile learning app-based quiz-games in higher education teaching of anatomical sciences

Background: Mobile learning (mLearning) and gamification are two potential pedagogical tools that are continuously evolving in Higher Education. Their efficiency as learning tools is not fully understood and their use by staff is sporadic and sometimes viewed poorly compared to traditional methods. Aim: To determine a framework of best practice for the integration of mLearning app based quiz-games into the Higher Education (HE) teaching of anatomical sciences. This thesis presents three studies, which aim to 1) evaluate mLearning quiz-games as a revision tool for an anatomy online examination 2) and 3) investigate the effect of pre-seminar mLearning quiz gameplay on knowledge acquisition, retention and engagement in anatomy. Method: The data collection was performed over a two year period in a level 4 anatomy module for Sport and Exercise Science students. All three studies employed an experimental mixed methods approach within an action research framework to allow the development of the project in a naturalistic way. Study One was completed over two cohorts, 2014-15 (n=125) and 2015-16 (n=121). The module has four assessment points, A1, A2, A3, A4 where A1-3 are online assessments with a mixture of Multiple Choice Questions, labelling and matching questions and A4 is a viva voce. Students did A1, A2 and A4 as normal but at A3 they were offered a choice to revise as normal, the control group (n= 164) or to play mLearning games (n=87) for 15 minutes prior to the assessment on a tablet or smartphone device. All students completed a modified Study Process Questionnaire (SPQ) post-assessment and then for triangulation of data online focus groups were completed (n=84) as well as extended semi-structured interviews (n=9). Study Two was completed in 2015-16 using the same module as Study One. Over two consecutive weeks students were videoed in a two hour seminar session where in week one they did 15 minutes of no formal class preparation (n=87) and in week two they did 15 minutes of mLearning games (n=87). Students did a plenary and recap class Socrative quiz every week where the plenary scores indicate knowledge acquisition and the difference between the plenary and recap scores of subsequent weeks indicates knowledge retention. Observational behavioural engagement analysis was completed using an adapted coding system and students completed the National Survey of Student Engagement following each seminar. Study Three was completed on the same cohort in semester two using a randomised repeated measures design for the knowledge acquisition and knowledge retention scores over three weeks with three 15 minute interventions; Games, Control and Games plus question generation before class. Results: Study One found that the Games group performed better at A3 with no difference at A2 or A1 (p<0.0.01) but no differences were found in the SPQ surface and deep learning motives and strategies. Students revealed reasons for using mLearning quiz-games were primarily the fun, visual stimulation, instant feedback and accessibility. Study Two found that playing quiz-games prior to class increased on-task behaviours and peer interaction and improved knowledge acquisition and retention scores (p<0.01). Study Three agreed but found no difference in the Games-plus questions group compared to the control or games groups. Conclusions: The studies reveal the positive effect that mLearning quiz-games can have on achievement and engagement both in class and as a revision tool prior to assessment. The results of all three studies have been used to inform the proposed Mobigames framework for the integration of mLearning quiz-games in HE teaching. The framework has four key aspects: Information, Facilitation, Learning and Timing

Ergodic and non-ergodic clustering of inertial particles

We compute the fractal dimension of clusters of inertial particles in mixing flows at finite values of Kubo (Ku) and Stokes (St) numbers, by a new series expansion in Ku. At small St, the theory includes clustering by Maxey's non-ergodic 'centrifuge' effect. In the limit of St to infinity and Ku to zero (so that Ku^2 St remains finite) it explains clustering in terms of ergodic 'multiplicative amplification'. In this limit, the theory is consistent with the asymptotic perturbation series in [Duncan et al., Phys. Rev. Lett. 95 (2005) 240602]. The new theory allows to analyse how the two clustering mechanisms compete at finite values of St and Ku. For particles suspended in two-dimensional random Gaussian incompressible flows, the theory yields excellent results for Ku < 0.2 for arbitrary values of St; the ergodic mechanism is found to contribute significantly unless St is very small. For higher values of Ku the new series is likely to require resummation. But numerical simulations show that for Ku ~ St ~ 1 too, ergodic 'multiplicative amplification' makes a substantial contribution to the observed clustering.Comment: 4 pages, 2 figure

Preliminary frameworks and models for telework maturity within organisations

This paper is a preliminary step to assess the feasibility of telework for any given organisation. We posit two qualitative frames of telework to define the additional, digital referential platforms that exist with regard to work today: abstraction and conceptualisation. To communicate research within this field we utilise a language taxonomy derived out of a review of the relevant literature. Furthermore, we propose a transformer model to serve as a means to i) interpret quantitative aspects of telework such as metrics and KPIs and ii) inform stakeholder decisions with regard to appropriate telework configurations for their respective company

Advective collisions

Small particles advected in a fluid can collide (and therefore aggregate) due to the stretching or shearing of fluid elements. This effect is usually discussed in terms of a theory due to Saffman and Turner [J. Fluid Mech., 1, 16-30, (1956)]. We show that in complex or random flows the Saffman-Turner theory for the collision rate describes only an initial transient (which we evaluate exactly). We obtain precise expressions for the steady-state collision rate for flows with small Kubo number, including the influence of fractal clustering on the collision rate for compressible flows. For incompressible turbulent flows, where the Kubo number is of order unity, the Saffman-Turner theory is an upper bound.Comment: 4 pages, 1 figur