Basic a mejoramiento exam v2

Written exam for students who have studied Units 1 to 9 in the Elementary Student´s Book of the Face2Face series published by Cambridge University Press

LES of additive and non-additive pulsatile flows in a model arterial stenosis

Transition of additive and non-additive pulsatile flows through a simple 3D model of arterial stenosis is investigated by using a large eddy simulation (LES) technique. We find in both the pulsatile cases that the interaction of the two shear layers, one of which separates from the nose of the stenosis and the another one from its opposite wall, causes recirculation in the flow downstream of the stenosis where the nature of the transient flow becomes turbulent. The strength of this recirculation is found to be quite high from the non-additive pulsations when the flow Reynolds numbers, Re ≥ 1500, for which both the pressure and shearing stresses take on an oscillating form at the post-stenotic region. Potential medical consequences of these results are discussed in the paper. In addition, some comparisons of the non-additive pulsatile results are given with those of both the additive pulsatile and steady flows. The capability of using LES to simulate the pulsatile transitional flow is also assessed, and the present results show that the smaller (subgrid) scales (SGS) contributes about 78% energy dissipation to the flow when the Reynolds number is taken as 2000. The level of SGS dissipation decreases as the Reynolds number is decreased. The numerical results are validated with the experimental data available in literature where a quite good agreement is found

Basic a final exam v4

Written exam for students who have completed Units 5C to 9D in the Face2Face Elementary Series published by Cambridge University Press

Analytical approximations for the orientation distribution of small dipolar particles in steady shear flows

Analytic approximations are obtained to solutions of the steady Fokker-Planck equation describing the probability density functions for the orientation of dipolar particles in a steady, low-Reynolds-number shear flow and a uniform external field. Exact computer algebra is used to solve the equation in terms of a truncated spherical harmonic expansion. It is demonstrated that very low orders of approximation are required for spheres but that spheroids introduce resolution problems in certain flow regimes. Moments of the orientation probability density function are derived and applications to swimming cells in bioconvection are discussed. A separate asymptotic expansion is performed for the case in which spherical particles are in a flow with high vorticity, and the results are compared with the truncated spherical harmonic expansion. Agreement between the two methods is excellent

Polling Matters: Why Plaid Cymru are not the SNP

Polling Matters is an independent, non-partisan podcast providing expert polling news and analysis, with guests, in the run up to the General Election. In the most recent episode, the team spoke to Roger Scully from the University of Cardiff to discuss the political situation in Wales and the role nationalist parties might play in Westminster in the event of a hung parliament after the election. In this post, Keiran Pedley examines why so little attention is paid to Welsh politics in Westminster and the opportunity the General Election presents for Plaid Cymru

Polling Matters: Political Betting – Place your bets now

Polling Matters is an independent, non-partisan podcast providing expert polling news and analysis, with guests, in the run up to the General Election. In the most recent episode, the team spoke to Matthew Shaddick from Ladbrokes politics about what the bookies make of the General Election overall and discussed some of the more interesting constituency battles

Polling matters: The ‘unstoppable’ rise of Boris Johnson?

Polling Matters is an independent, non-partisan podcast providing expert polling news and analysis, with guests, in the run up to the General Election. In the most recent episode, the team sat down with Tony Travers from the LSE to discuss all things London, including the seats that matter in May, devolution and PR for local Government and who might replace Boris Johnson in 2016. In this post, Keiran Pedley examines the Mayor’s popularity and what his future may hold

Polling Matters: Will it be 1992 all over again for the pollsters?

Polling Matters is an independent, non-partisan podcast providing expert polling news and analysis, with guests, in the run up to the General Election. In the most recent episode, the team spoke to Chris Hanretty from electionforecast.co.uk and a reader in politics at the University of East Anglia. We discussed his forecasting model and the challenges faced in projecting the most unpredictable election in a generation