Vortex breakdown incipience: Theoretical considerations

The sensitivity of the onset and the location of vortex breakdowns in concentrated vortex cores, and the pronounced tendency of the breakdowns to migrate upstream have been characteristic observations of experimental investigations; they have also been features of numerical simulations and led to questions about the validity of these simulations. This behavior seems to be inconsistent with the strong time-like axial evolution of the flow, as expressed explicitly, for example, by the quasi-cylindrical approximate equations for this flow. An order-of-magnitude analysis of the equations of motion near breakdown leads to a modified set of governing equations, analysis of which demonstrates that the interplay between radial inertial, pressure, and viscous forces gives an elliptic character to these concentrated swirling flows. Analytical, asymptotic, and numerical solutions of a simplified non-linear equation are presented; these qualitatively exhibit the features of vortex onset and location noted above

Geology and Acid Intrusions of Marlboro Township, Vermont

It is the aim of this paper to examine the mineralization resulting from the intrusion of acid dikes and veins into the schists of Marlboro township, Vermont, and to give a brief account of the geology of the area. The problem of mineralization in southern Vermont is one which has been treated very slightly and is one which is deserving of more study than it has received. This problem results from the presence of numerous acid igneous masses in all the formation of the region. Petrographic research in the igneous intrusions was done partially with the hope that the study would reveal minerals of economic importance and partially for the knowledge which the study would yield

Antarctic Ocean polynyas

The spatial and temporal variability of sea ice concentrations derived from Nimbus-7 Scanning Multichannel Microwave Radiometer (SMMR) brightness temperatures are presented. Emphasis is on the continental shelf region of the Ross Sea during 1984, when supporting data were obtained from oceanographic stations and moored instruments. The effects of the large spring polynya in the Ross Sea on summer insolation, surface heat layer storage, and late autumn ice formation are described

Restructuring Teacher Education

As part of the process of developing a four year Bachelor of Education in September 1994, Edith Cowan University conducted a public seminar entitled \u27\u27Restructuring Teacher Education . The invited speakers were Dr Shirley Grundy (Murdoch University), Professor Bob Meyenn (Charles Sturt University), Sandra Milligan (Ashenden Milligan Pty Ltd), Professor Paige Porter (University of Western Australia), Greg Robson (Education Department of Western Australia and Professor Gordon Stanley (Education Policy and Coordination Bureau). Two of the presentations are published here to inform others engaged in the tasks of restructuring teacher education

Item Banking with Embedded Standards

An item banking method that does not use Item Response Theory (IRT) is described. This method provides a comparable grading system across schools that would be suitable for low-stakes testing. It uses the Angoff standard-setting method to obtain item ratings that are stored with each item. An example of such a grading system is given, showing how a grade and a scaled score could be calculated for a particular student. Accessed 10,825 times on https://pareonline.net from October 14, 2009 to December 31, 2019. For downloads from January 1, 2020 forward, please click on the PlumX Metrics link to the right

Estimating the Standard Error of the Judging in a modified-Angoff Standards Setting Procedure

For a modified Angoff standards setting procedure, two methods of calculating the standard error of the judging were compared. The Central Limit Theorem (CLT) method is easy to calculate and uses readily available data. It estimates the variance of mean cut scores as a function of the variance of cut scores within a judging group, based on the independent judgements at Stage 1 of the process. Its theoretical drawback is that it is unable to take account of the effects of collaboration among the judges at Stages 2 and 3. The second method, an application of equipercentile (EQP) equating, relies on the selection of very large stable candidatures and the standardisation of the raw score distributions to remove effects associated with test difficulty. The standard error estimates were then empirically obtained from the mean cut score variation observed over a five year period. For practical purposes, the two methods gave reasonable agreement, with the CLT method working well for the top band, the band that attracts most public attention. For some bands in English and Mathematics, the CLT standard error was smaller than the EQP estimate, suggesting the CLT method be used with caution as an approximate guide only. Accessed 31,793 times on https://pareonline.net from March 01, 2004 to December 31, 2019. For downloads from January 1, 2020 forward, please click on the PlumX Metrics link to the right

The Use of Rasch Modeling To Improve Standard Setting

As a wider variety of meaningful assessment strategies come into more prominent classroom use, teachers are called upon to craft scoring rubrics which validly and reliably assess students\u27 knowledge and abilities. The creation of instructionally sound rubrics can be time consuming, and many teachers feeling the pinch of time pressures are turning to rubric resources from the World Wide Web for assistance. The purposes of this paper are to review the issues surrounding the creation of instructionally sound rubrics, to examine how those issues apply to online rubric banks and rubric generators, and to offer guidelines for how educators can use online resources to best support the creation of meaningful and effective rubrics. Accessed 20,478 times on https://pareonline.net from January 24, 2006 to December 31, 2019. For downloads from January 1, 2020 forward, please click on the PlumX Metrics link to the right

RELAXATION AS A MEANS OF PAIN CONTROL1 1Received April, 1976.

The effectiveness of relaxation techniques as a means of increasing pain threshold and pain tolerance and of decreasing anxiety was tested. Forty-two physiotherapy students were divided into experimental and control groups and tested on pain threshold, pain tolerance and anxiety. The 21 experimental group subjects were given one session of relaxation and then re-tested. Their results showed that a single session of relaxation significantly increased their pain threshold and pain tolerance and decreased their anxiety about the situation. No such changes were noted when the control group was re-tested

High-order ENO schemes applied to two- and three-dimensional compressible flow

High order essentially non-oscillatory (ENO) finite difference schemes are applied to the 2-D and 3-D compressible Euler and Navier-Stokes equations. Practical issues, such as vectorization, efficiency of coding, cost comparison with other numerical methods, and accuracy degeneracy effects, are discussed. Numerical examples are provided which are representative of computational problems of current interest in transition and turbulence physics. These require both nonoscillatory shock capturing and high resolution for detailed structures in the smooth regions and demonstrate the advantage of ENO schemes