1,126 research outputs found
Monte Carlo Simulation Of Fe-co Amorphous Nanoparticles Magnetization
No full textMagnetization simulations of ∼3 nm non-interacting Fe-Co ferromagnetic amorphous nanoparticles were made using Metropolis algorithm of Monte Carlo method. The results of core-shell model simulations describe the nanoparticles as a ferromagnetically ordered core and a disordered surface shell. They fairly reproduce the significant features observed in 3 nm Fe-Co-B nanoparticles experimental magnetization measurement at the same Fe-Co composition. They also provide a clear evidence of the role played by the local surface anisotropy and the surface-core exchange interaction in determining the magnetic properties of the nanoparticles. © 2007 Elsevier B.V. All rights reserved.4032-3390393De Biasi, E., Ramos, C.A., Zysler, R.D., Romero, H., (2002) Phys. Rev. B, 65, p. 144416Zysler, R.D., Romero, H., Ramos, C.A., De Biasi, E., Fiorani, D., (2003) J. Magn. Magn. Mater., 266, p. 233Kachkachi, H., Ezzir, A., Noguès, M., Tronc, E., (2000) Eur. Phys. J. B, 14, p. 681Winkler, E., Zysler, R.D., Vasquez Mansilla, M., Fiorani, D., (2005) Phys. Rev. B, 72, p. 132409Iglesias, O., Labarta, A., (2001) Phys. Rev. B, 63, p. 184416Iglesias, O., Labarta, A., (2004) Physica B, 343, p. 286De Biasi, E., Ramos, C.A., Zysler, R.D., Fiorani, D., (2006) Physica B, 372, p. 345Chikazumi, S., (1964) Physics of Magnetism, , Krieger Publ. Co., Malabar, FL (Chapter 4)Molina Concha, B., Zysler, R.D., Romero, H., (2006) Physica B, 384, p. 274De Biasi, E., Ramos, C.A., Zysler, R.D., Romero, H., Fiorani, D., (2005) Phys. Rev. B, 71, p. 10440
Solution of the problem of composite charge using R.D.38
No full textIn this paper the author has solved the problem of internal ballistics of composite charge using 'R.D.38' method which is based upon the usual isothermal approximation. A linear law of burning has been assumed
Author index
No full textThe articles have been scanned in colour with a HP Scanjet 5590; 300dpi.
Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.This is a continuation of the "Author and Subject Index to the Onderstepoort Journal
of Veterinary Science and Animal Industry (1933- l950)" and the "Onderstepoort Journal
of Veterinary Research (1951 - 1968)" which appeared in June 1969 and covers the period
1969 to 1973, i.e. Volumes 36 to 40.
As from 1974 (Volume 41) it is intended to furnish an Author and Subject Index
in Number 4 of each volume covering all four numbers for that particular year
Noise due to unsteady flow past trailing edges
No full textThis paper presents two-dimensional direct numerical simulations (DNS) of noise generated at trailing edges (TE) with zero thickness. The simulations are conducted specifying either no-slip or slip walls in order to investigate viscous effects. In both cases, small amplitude disturbances are introduced close to the inflow boundary that serve as pressure disturbances at the TE. DNS data reveals that the unsteady Kutta condition is not satisfied, irrespective of the wall boundary condition. However, it appears that the validity of the unsteady Kutta condition is not essential for making an accurate prediction of the far field noise. The far field pressure is predicted as a function of the surface pressure difference using a 2-D modification of Amiet's classical theory, and compared with the far field pressure computed directly. Directivity plots provide evidence that the presence of boundary layers and noise generated by an unsteady wake in the no-slip cases lead to smearing of individual lobes, and that the downstream pointing lobes in no-slip wall cases are probably due to nonlinear noise generation in the wake. The simulations are conducted using a high-order accurate numerical method which is free of upwinding, artificial dissipation or any form of explicit filtering, and employs a novel boundary treatment
Characteristic distribution and scale interaction of turbulence in a boundary layer
No full textThis work revisits the concept of turbulent boundary layers from a novel perspective on scale transfer. Turbulence production and dissipation together with the energy budgets are analyzed in the velocity gradient invariant phase space. In combination with filtering, the mechanism of scale coupling is investigated and illustrated for different characteristic flow topologies. The understanding of the scale coupling is important to model turbulence. Turbulence models describe the complex interaction of the scales of motion in a simplified form. The essential task of turbulence modeling is to capture the coupling of the modeled and unmodeled scales as well as the evolution of the modeled scales within the unmodeled flow. This work characterizes the scale coupling by focusing on the interfaces between modeled and unmodeled flow such as production and dissipation. The mechanisms that govern the evolution of the modeled quantities are investigated for their core properties and universal features. Direct numerical simulation (DNS) is carried out to obtain data of a compressible zero pressure-gradient flat plate turbulent boundary layer flow. This flow topology allows to unveil the effect of a wall on the coupling of scales and evolution of turbulence
Learning from One's Mistakes
No full textCreated by R.D. Lee for the Royal Statistics Society, this article describes an exercise, which highlights the effect of sampling without replacement in small populations, and leads to consideration of the relative importance of sample and population size when examining standard error. The author provides a number of exercises, an explanation of statistical errors and the importance of sample size. This is a brief, yet fine resource for those in the field of statistics
Mad to be Normal: Thoughts on Psychiatrist R.D Laing and Connections to Liberation Psychology
No full textThis article uses the film Mad to be Normal, about R.D. Laing, as an opening into the liberation psychology approaches of Martin-Baro. Examples from the author\u27s own clinical practice as well as personal experiences from life in a Catholic Worker community are included
R.D. Laing's language of experience
No full textThe radical psychiatrist R.D. Laing (1927-1989) was an accomplished author with an extensive philosophical knowledge that informed his ideas on reading, writing, and interpretation. Laing argues that psychiatry should be modeled on skilful textual exegesis rather than scientific explanation. The exegesis of a psychotic’s words and actions is difficult, he infers, because the impoverishment of our experience cuts us off from the sense that lies within seeming madness. Like philosophers such as Edmund Husserl, Laing therefore criticizes the way in which the natural sciences have invalidated subjective experience. He consequently employs a rhetoric designed to disclose with renewed vigor its complexity, variety and reality. Laing fails, however, to find an alternative to scientific reason: "experience", in his weakest work, is an irrational realm of mystical and self-validating certainty that closely parallels Heidegger’s later accounts of "Being"
Naval engineering and ship control special edition editorial
No full textEditorial Special Issue: Naval Engineering and Ship Control IIGreen Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Ship Design, Production and Operation
Using and evaluating CASE tools : from software engineering to phenomenology
No full textCASE (Computer-Aided Systems Engineering) is a recent addition to the long line of
"silver bullets" that promise to transform information systems development, delivering
new levels of quality and productivity. CASE is particularly intriguing because
information systems (IS) practitioners spend their working lives applying information
technology (IT) to other people's work, and now they are applying it to themselves.
CASE research to date has been dominated by accounts of tool development,
normative writings (for example practitioner success stories) and surveys recording
IT specialists' perceptions. There have been very few in-depth studies of tool use,
and very few attempts to quantify benefits, therefore the essence of the CASE process
remains largely unexplored, and the views of stakeholders other than the IT specialists
have yet to be heard.
The research presented here addresses these concerns by adopting a hybrid research
approach combining action research, grounded theory and phenoinenology and using
both qualitative and quantitative data in order to tell the story of a system developer's
experience in using CASE tools in three information systems projects for a major UK
car manufacturer over a four year period. The author was the lead developer on all
three projects. Action research is a learning process, the researcher is an explorer.
At the start of this project it was assumed that the tools would be the focus of the
work. As the research progressed it became evident that the tools were but part of
a richer organisational context in which culture, politics, history, external initiatives
and cognitive limitations played important roles. The author continued to record
experiences and impressions of tool use in the project diary together with quality and
productivity metrics. But the diary also became home to a story of organisational
developments that had not originally been foreseen.
The principal contribution made by the work is to identity the narrow positivistic
nature of CASE knowledge, and to show via the research stories the overwhelming
importance of organisational context to systems development success and how the
exploration of context is poorly supported by the tools. Sixteen further contributions
are listed in the Conclusions to the thesis, including a major extension to Wynekoop
and Conger's CASE research taxonomy, an identification of the potentially
misleading nature of quantitative IS assessment and further evidence of the limitations
of the "scientific" approach to systems development.
The thesis is completed by two proposals for further work. The first seeks to
advance IS theory by developing further a number of emerging process models of IS
development. The second seeks to advance IS practice by asking the question "How
can CASE tools be used to stimulate awareness and debate about the effects of
organisational context?", and outlines a programme of research in this area
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