A Large Eddy Simulation of Turbulent Compressible Convection: Differential Rotation in the Solar Convection Zone

We present results of two simulations of the convection zone, obtained by solving the full hydrodynamic equations in a section of a spherical shell. The first simulation has cylindrical rotation contours (parallel to the rotation axis) and a strong meridional circulation, which traverses the entire depth. The second simulation has isorotation contours about mid-way between cylinders and cones, and a weak meridional circulation, concentrated in the uppermost part of the shell. We show that the solar differential rotation is directly related to a latitudinal entropy gradient, which pervades into the deep layers of the convection zone. We also offer an explanation of the angular velocity shear found at low latitudes near the top. A non-zero correlation between radial and zonal velocity fluctuations produces a significant Reynolds stress in that region. This constitutes a net transport of angular momentum inwards, which causes a slight modification of the overall structure of the differential rotation near the top. In essence, the {\it thermodynamics controls the dynamics through the Taylor-Proudman momentum balance}. The Reynolds stresses only become significant in the surface layers, where they generate a weak meridional circulation and an angular velocity `bump'.Comment: 11 pages, 14 figures, the first figure was too large and is excluded. Accepted for publication in MNRA

The effect of thermal performance on device current utilisation

A significant improvement in power semiconductor device utilisation seems possible if the maximum output current of power stages could be limited by thermal feedback from the power converter. To illustrate the potential utilisation benefit obtained in main switching devices, the variation in usable current with operating conditions is examined for several devices applied in a constant frequency PWM VVVF inverter, and operated under conditions to keep their junction temperature constan

Maximising device current utilisation in inverter drives

A considerable improvement in power semiconductor device utilisation seems possible if the output current of power stages is actively limited by thermal feedback from the power converter. To illustrate the potential utilisation benefit in main switching devices, the variation in usable current with operating conditions is examined for several devices used in a constant frequency PWM VVVF inverter, and operated under conditions to keep their junction temperature constan

Biocultural Community Protocols: Dialogues on the Space Within

This paper starts by explaining "the space within" -- the ethical grammar and code by which indigenous peoples use and steward nature. It then explains the inextricable links with nature demonstrated by a number of communities with which we have worked, and their experiences in the ABS context. It discusses the importance of processes of prior informed consent, before then discussing the possibility of "tools of conviviality" that may act as bridges between the fundamental ecological principals of indigenous peoples, and the researchers and companies that seek to utilize biodiversity and knowledge within community control.In the final sections, we explore the use of both community protocols and Ethical BioTrade, with some examples, and their potential role as tools of conviviality -- opening up dialogues between actors from vastly different worldviews. While we do not see community protocols as a panacea for the rights of indigenous peoples and local communities, we have seen them act as an important step towards the protection of indigenous knowledge and the recognition of legal pluralism

The Role of Eye Movement Habits in Determining Reading Efficiency

Since there is a correlation of about.60 between reading comprehension and eye movements, it is of importance psychologically to understand the nature of this relationship. Three possible causal relationships may exist. First, comprehension may determine the action of the eyes in reading; second, certain functions of eye movement may determine reading efficiency; or third, some undescribed factor may affect each of these and account for the relationship

Remedial Measures in Reading at the College Level

Reading ability is highly related to school success. College freshmen with inferior ability have a high scholastic mortality and those that do remain in school are hampered in gaining knowledge. Therefore, a remedial unit has been inaugurated at the University of Iowa to aid the lowest quarter in reading ability. A clinical method is used, each case being handled individually which allows each difficulty to be treated and makes for better rapport. A complete analysis is made of the student\u27s abilities and weaknesses and work is directed to remove these defects. Various methods of reading and their uses are also given. The comparison of preliminary and end tests shows gains in comprehension up to 60 percentiles while rate of reading has been doubled. Further, an analysis of the fortnightly delinquency reports shows only half as many receive delinquencies on the last report as on the first and only 40% as many delinquencies. It is to be concluded, then, that remedial training in reading is feasible at the college level