Heat and Hall Effect of an Oscillating Plate in a Porous Medium

An exact solution of the flow of heat and viscous fluid on a porous plate by using perturbation is obtained for the conjugate problem of an electrically conducting fluid in the presence of strong magnetic field by introducing the Hall currents. The fluid half-space is considered to be porous. Large time solution and effects of porous medium are discussed. It was shown that Hall Effect setup an opposing force which reduces the velocity. Temperature and velocity distributions have been obtained and the effect of various values of nondimensional physical parameters on streamline patterns and skin friction coefficient and Nusselt number are presented and discusse

Effect of Slip Velocity on Oscillatory MHD Flow of Stretched Surface with Radiative Heat Transfer and Variable Suction

The study of unsteady magnetohydrodynamic heat and mass transfer in MHD flow of an incompressible, electrically conducting, viscous fluid past an infinite vertical porous plate along with porous medium of time dependent permeability with radiative heat transfer and variable suction has been made. Analytical solution of an oscillatory boundary layer flow bounded by two horizontal flat plates, one of which is oscillating in its own plane and the other at rest, is developed by asymptotic expansion in order of epsilon for velocity, temperature and magnetic fields. The fluid and the plates are in a state of solid body rotation with constant angular velocity about the z-axis normal to the plates. The structure of the boundary layers is also discussed. Several known results of interest are found to follow as particular cases of the solution of the problem considered. A parametric study of all parameters involved was considered, and a representative set of results showing the effect of controlling parameters are illustrated

The sound of higher education: sensuous epistemologies and the mess of knowing

The soundscape of higher education is changing. The changes reflect an age of managerialism and an age of uncertainty. These changes call on us to give up on some of the ways we have understood knowledge in the past and prompt us to find news ways of recognizing and understanding the complexities facing higher education research. This paper explores the possibilities opened up by perceptions of higher education gained through the senses, especially through the auditory sense. Taking the case of modern languages it t some of the contours of the soundscape of higher education – its grief and its diversity

Overhead and noise threshold of fault-tolerant quantum error correction

Fault tolerant quantum error correction (QEC) networks are studied by a combination of numerical and approximate analytical treatments. The probability of failure of the recovery operation is calculated for a variety of CSS codes, including large block codes and concatenated codes. Recent insights into the syndrome extraction process, which render the whole process more efficient and more noise-tolerant, are incorporated. The average number of recoveries which can be completed without failure is thus estimated as a function of various parameters. The main parameters are the gate (gamma) and memory (epsilon) failure rates, the physical scale-up of the computer size, and the time t_m required for measurements and classical processing. The achievable computation size is given as a surface in parameter space. This indicates the noise threshold as well as other information. It is found that concatenated codes based on the [[23,1,7]] Golay code give higher thresholds than those based on the [[7,1,3]] Hamming code under most conditions. The threshold gate noise gamma_0 is a function of epsilon/gamma and t_m; example values are {epsilon/gamma, t_m, gamma_0} = {1, 1, 0.001}, {0.01, 1, 0.003}, {1, 100, 0.0001}, {0.01, 100, 0.002}, assuming zero cost for information transport. This represents an order of magnitude increase in tolerated memory noise, compared with previous calculations, which is made possible by recent insights into the fault-tolerant QEC process.Comment: 21 pages, 12 figures, minor mistakes corrected and layout improved, ref added; v4: clarification of assumption re logic gate

The power and vulnerability of the ‘new professional’: Web management in UK universities

Research paper Purpose: To explore the character of an emergent occupational role, that of university web manager. Design/methodology/approach: The primary data used were 15 semi-structured interviews conducted in 2004. These were analysed partly for factual and attitudinal data, but also for the discursive interpretative repertoires in use. Findings: The paper examines the diverse backgrounds, occupational trajectories, organisational positions, job roles and status of practitioners working in ‘web management’ in UK Higher Education. The discursive divide between the marketing and IT approaches to the web is investigated. Two case studies explore further the complexity and creativity involved in individuals’ construction of coherent and successful occupational identities. Research implications / limitations: The paper examines the position of web managers within the framework of the notions of the marginal but powerful ‘new professional’ or ‘broker’ technician. It gives a vivid insight into how the web as a dynamic and open technology opens up opportunities for new forms of expertise; but also explores the potential vulnerabilities of such new roles. In order to examine personal experience in depth, data was gathered for only a relatively small number of individuals. The research was also limited to the UK university sector and to those with a broad responsibility for the web site of the whole institution, i.e. not library web managers and other web authors who work primarily to produce a departmental web presence. These limits imply obvious ways in which the research could be extended. Practical implications: There are implications for how institutions support people in such roles, and for how they can support each other. Originality: There is a vast literature about the web, little about the new work roles that have grown up around it

The well-being of British expatriate retirees in southern Europe

This article examines the personal outcomes of overseas residence in later life, by analysing some findings from the first large-scale, comparative study of the retirement of British citizens to southern Europe. Four study areas are compared: Tuscany in Italy, Malta, the Costa del Sol of Spain, and the Algarve region of Portugal. The analysis focuses on the expressed reasons for moving to and residing in the areas, the reported advantages and disadvantages, and the respondents' predictions of whether they would stay or leave in response to adverse and beneficial events. Overall the subjects give very positive reports, but there are considerable differences among the four areas. The associations of individual variation in well-being with both a person's ‘temporal commitment’ to the area and to facets of their social integration are analysed. The onset of severe incapacity, sufficient to prevent the continued running of a home, is the event most likely to cause people to leave their adopted areas of residence

Symmetry-breaking instabilities of convection in squares

Convection in an infinite fluid layer is often modelled by considering a finite box with periodic boundary conditions in the two horizontal directions. The translational invariance of the problem implies that any solution can be translated horizontally by an arbitrary amount. Some solutions travel, but those solutions that are invariant under reflections in both horizontal directions cannot travel, since motion in any horizontal direction is balanced by an equal and opposite motion elsewhere. Equivariant bifurcation theory allows us to understand the steady and time-dependent ways in which a pattern can travel when a mirror symmetry of the pattern is broken in a bifurcation. Here we study symmetry-breaking instabilities of convection with a square planform. A pitchfork bifurcation leads to squares that travel uniformly, while a Hopf bifurcation leads to a new class of oscillations in which squares drift to and fro but with no net motion of the pattern. Two types of travelling squares are possible after a pitchfork bifurcation, and three or more oscillatory solutions are created in a Hopf bifurcation. One of the three oscillations, alternating pulsating waves, has been observed in recent numerical simulations of convection in the presence of a magnetic field. We also present a low-order model of three-dimensional compressible convection that contains these symmetry-breaking instabilities. Our analysis clarifies the relationship between several types of time-dependent patterns that have been observed in numerical simulations of convection

Understanding the formation of twinned dendrites (‘feather’ grains)

The phenomenon of feather grain growth is interesting from both a theoretical and commercial point of view. Here we report the results of phase-field simulations aimed at understanding the formation of twinned dendrites. We show that, while a competition between oppositely directed capillary and kinetic anisotropies with a simple four-fold symmetry can produce low anisotropy structures such as dendritic seaweed, there is no indication that this can give rise to twinned dendrites. In contrast, adding small components of an anisotropy, with higher order harmonics, can produce features reminiscent of twinned dendrites and may also be able to stabilise the grooved tip morphology

Menstrual cycle patterns of college students in Gorgan-Northeast of Iran: Identify its association with sociodemographic factors

Purpose: The menstrual cycle is used as a sign of women's health. Objective of study is determining the current menstrual patterns of students in Gorgan-Northeast of Iran, and evaluation of affecting factors on the cycle. Material and Methods: The study participants included 106 college student, females aged 18-30 that filled a questionnaire to detect the menstrual pattern, affecting factors on menstrual cycle. Main outcomes of variables compared using ANOVA. Logistic regression was used to model factors for menstrual regularity. Results: The mean ± SD age, menstruation lengths, age at menarche in student girls were 20.58±2.13, 28.02±1.88 and 13.53±1.30, respectively. 59.2% of girls had age 20-25 and 39.8% of these students had normal cycle. Also of 53.4 % of students with normal cycle, 31.8% of students had body mass index 20-24.99. Age at menarche of 56.8% of all participants was 13-14 years. Comparison of regression coefficients between factors and reported menstrual patterns shows similar results for students of all categories of menstrual cycle. Conclusion: This study provides a look at negative correlation of menstrual cycle's length with factors in college students of Gorgan - Northeast of Iran and points to importance of racial differences