17,765 research outputs found
Geomagnetic modeling by optimal recursive filtering
The results of a preliminary study to determine the feasibility of using Kalman filter techniques for geomagnetic field modeling are given. Specifically, five separate field models were computed using observatory annual means, satellite, survey and airborne data for the years 1950 to 1976. Each of the individual field models used approximately five years of data. These five models were combined using a recursive information filter (a Kalman filter written in terms of information matrices rather than covariance matrices.) The resulting estimate of the geomagnetic field and its secular variation was propogated four years past the data to the time of the MAGSAT data. The accuracy with which this field model matched the MAGSAT data was evaluated by comparisons with predictions from other pre-MAGSAT field models. The field estimate obtained by recursive estimation was found to be superior to all other models
Generalization of analytical tools for helicopter-rotor airfoils
A state-of-the-art finite difference boundary-layer program incorporated into the NYU Transonic Analysis Program is described. Some possible treatments for the trailing edge region were investigated. Findings indicate the trailing edge region, still within the scope of an iterative potential flow, boundary layer program, appears feasible
Information-theoretic determination of ponderomotive forces
From the equilibrium condition applied to an isolated
thermodynamic system of electrically charged particles and the fundamental
equation of thermodynamics () subject
to a new procedure, it is obtained the Lorentz's force together with
non-inertial terms of mechanical nature. Other well known ponderomotive forces,
like the Stern-Gerlach's force and a force term related to the Einstein-de
Haas's effect are also obtained. In addition, a new force term appears,
possibly related to a change in weight when a system of charged particles is
accelerated.Comment: 10 page
Elastic Scattering of Pions From the Three-nucleon System
We examine the scattering of charged pions from the trinucleon system at a
pion energy of 180 MeV. The motivation for this study is the structure seen in
the experimental angular distribution of back-angle scattering for pi+ 3He and
pi- 3H but for neither pi- 3He nor pi+ 3H. We consider the addition of a double
spin flip term to an optical model treatment and find that, though the
contribution of this term is non-negligible at large angles for pi+ 3He and pi-
3H, it does not reproduce the structure seen in the experiment.Comment: 15 pages + 5 figure
Recommended from our members
Independent reporting sonographers-could other countries follow the UK's lead 2017
The rapid growth in the use of ultrasound as a diagnostic imaging technology over the past 40 years, has led to a demand for a workforce with the appropriate skills to perform and interpret the scans. For many years, the majority of ultrasound examinations in the United Kingdom (UK), both obstetric and non-obstetric, have been performed by radiographers who have undergone postgraduate training. These ‘sonographers’ scan, interpret and report their own examinations. Today, sonographer-led ultrasound services are essential and well established. The second largest professional group performing ultrasound in the UK comprises radiologists. Other groups including midwives, obstetricians, emergency physicians and abdominal aortic aneurysm screening technicians, also contribute to services. This model is successful yet it appears to be unique1. No other country relies so heavily on sonographers. Throughout mainland Europe, physicians and general practitioners perform a significant proportion of ultrasound examinations, having undergone very variable levels of training in ultrasound. Alternatively, sonographers may perform the scans but reporting remains the domain of the overseeing medical staff. For example, in countries such as Australia, Canada and the United States, ultrasound might be performed by sonographers but there is little evidence of independent reporting. However, the escalating need for ultrasound services is now causing some teams, particularly from Australia and some mainland European countries, to start focusing their attention on the UK model as a possible solution to meet demand
Struggling and juggling: a comparison of assessment loads in research and teaching-intensive universities
In spite of the rising tide of metrics in UK higher education, there has been scant attention paid to assessment loads, when evidence demonstrates that heavy demands lead to surface learning. Our study seeks to redress the situation by defining assessment loads and comparing them across research-and teaching intensive universities. We clarify the concept of ‘assessment load’ in response to findings about high volumes of summative assessment on modular degrees. We define assessment load across whole undergraduate degrees, according to four measures: the volume of summative assessment; volume of formative assessment; proportion of examinations to coursework; number of different varieties of assessment. All four factors contribute to the weight of an assessment load, and influence students’ approaches to learning. Our research compares programme assessment data from 73 programmes in 14 UK universities, across two institutional categories. Research-intensives have higher summative assessment loads and a greater proportion of examinations; teaching-intensives have higher varieties of assessment. Formative assessment does not differ significantly across both university groups. These findings pose particular challenges for students in different parts of the sector. Our study questions the wisdom that ‘more’ is always better, proposing that lighter assessment loads may make room for ‘slow’ and deep learning
Matrix bandwidth and profile reduction
This program, REDUCE, reduces the bandwidth and profile of sparse symmetric matrices, using row and corresponding column permutations. It is a realization of the algorithm described by the authors elsewhere. It was extensively tested and compared with several other programs and was found to be considerably faster than the others, superior for bandwidth reduction and as satisfactory as any other for profile reduction
A survey of the problems created by transfer students in business education in the high school of Massachusetts
Thesis (Ed.M.)--Boston Universit
- …
