4,570 research outputs found
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Andragogy and the single session lecture: A critical reflection on the planning and delivery of a standalone postgraduate teaching event
This paper focuses on a lecture delivered each year to postgraduates within the Department of Information Science at City University. The teaching context is outlined at personal, institutional and national levels through which the challenges facing a visiting lecturer are illustrated. The relevance of andragogy to this piece is then introduced.
These andragogical principles provide a framework in which to examine how the challenge of student engagement was resolved or exacerbated by the single lecture format, and how planning and delivery may also have contributed to this challenge. Engagement in the postgraduate context can be seen to depend on how well each of these principles is supported by the teaching methods used, and so realistic alterations which could be made in the future to promote deeper engagement are also considered
Analysis and calculation of macrosegregation in a casting ingot. MPS solidification model. Volume 1: Formulation and analysis
The physical and numerical formulation of a model for the horizontal solidification of a binary alloy is described. It can be applied in an ingot. The major purpose of the model is to calculate macrosegregation in a casting ingot which results from flow of interdendritic liquid during solidification. The flow, driven by solidification contractions and by gravity acting on density gradients in the interdendritic liquid, was modeled as flow through a porous medium. The symbols used are defined. The physical formulation of the problem leading to a set of equations which can be used to obtain: (1) the pressure field; (2) the velocity field: (3) mass flow and (4) solute flow in the solid plus liquid zone during solidification is presented. With these established, the model calculates macrosegregation after solidification is complete. The numerical techniques used to obtain solution on a computational grid are presented. Results, evaluation of the results, and recommendations for future development of the model are given. The macrosegregation and flow field predictions for tin-lead, aluminum-copper, and tin-bismuth alloys are included as well as comparisons of some of the predictions with published predictions or with empirical data
MPS solidification model. Analysis and calculation of macrosegregation in a casting ingot
Work performed on several existing solidification models for which computer codes and documentation were developed is presented. The models describe the solidification of alloys in which there is a time varying zone of coexisting solid and liquid phases; i.e., the S/L zone. The primary purpose of the models is to calculate macrosegregation in a casting or ingot which results from flow of interdendritic liquid in this S/L zone during solidification. The flow, driven by solidification contractions and by gravity acting on density gradients in the interdendritic liquid, is modeled as flow through a porous medium. In Model 1, the steady state model, the heat flow characteristics are those of steady state solidification; i.e., the S/L zone is of constant width and it moves at a constant velocity relative to the mold. In Model 2, the unsteady state model, the width and rate of movement of the S/L zone are allowed to vary with time as it moves through the ingot. Each of these models exists in two versions. Models 1 and 2 are applicable to binary alloys; models 1M and 2M are applicable to multicomponent alloys
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Informational balance: slow principles in the theory and practice of information behaviour
Purpose: The purpose of this paper is to investigate whether the principles of the Slow Movement may be applied to information behaviour.
Design/methodology/approach: The study uses three methods: a literature analysis and synthesis; a Delphi study; and a focus group. All are carried out in accordance with Slow principles, to assess the value of Slow in the conduct of the research itself.
Findings: Slow principles are applicable to both the theory and practice of information behaviour. They allow theory to be more realistic by encompassing a broader range of behaviours than those included in most established models of information behaviour and information literacy, particularly behaviours relating to temporal and experiential factors. The use of Slow principles in information practice may help to overcome problems relating to personal information management. The notion of “informational balance” stems from Slow ideas and is a useful concept for theory and practice.
Research limitations/implications: The empirical parts of the study use small groups of participants, and the emphasis of the focus group in particular was on everyday information, rather than on professional or academic information. The results of the study show that research and theory in information behaviour would benefit form more explicit attention to time factors.
Practical implications: The findings may be used in the design of information literacy instruction, and in encouraging a more reflective approach to personal information management.
Originality/value: This is the first study to examine the applicability of Slow principles in an information context. It is also original in explicitly applying Slow principles to the research design
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Slow Delphi: An investigation into information behaviour and the Slow Movement
As part of a wider study of the relevance of the principles and practices of the Slow Movement to the information disciplines and professions, a Delphi study was carried out with 17 researchers in information behaviour and practices. A novel variant of the Delphi technique, termed the Slow Delphi, was devised for this study. This is aimed at eliciting qualitative understanding of complex conceptual topics, where there are a variety of perspectives and positions to be considered. The results of the study show a variety of points of potential applicability of Slow principles in research into information behaviour and practices, and in information provision. These include: more explicit inclusion of a temporal dimension in information behaviour models; greater recognition of the importance of the tempo of information seeking; more critical consideration of speed and scale as factors in the information environment; and the potential for individuals to exercise greater control over their information environment
Quantum Hall effect in exfoliated graphene affected by charged impurities: metrological measurements
Metrological investigations of the quantum Hall effect (QHE) completed by
transport measurements at low magnetic field are carried out in
a-few--wide Hall bars made of monolayer (ML) or bilayer (BL)
exfoliated graphene transferred on substrate. From the
charge carrier density dependence of the conductivity and from the measurement
of the quantum corrections at low magnetic field, we deduce that transport
properties in these devices are mainly governed by the Coulomb interaction of
carriers with a large concentration of charged impurities. In the QHE regime,
at high magnetic field and low temperature (), the Hall
resistance is measured by comparison with a GaAs based quantum resistance
standard using a cryogenic current comparator. In the low dissipation limit, it
is found quantized within 5 parts in (one standard deviation, ) at the expected rational fractions of the von Klitzing constant,
respectively and in the ML and BL
devices. These results constitute the most accurate QHE quantization tests to
date in monolayer and bilayer exfoliated graphene. It turns out that a main
limitation to the quantization accuracy, which is found well above the
accuracy usually achieved in GaAs, is the low value of the QHE
breakdown current being no more than . The current dependence
of the longitudinal conductivity investigated in the BL Hall bar shows that
dissipation occurs through quasi-elastic inter-Landau level scattering,
assisted by large local electric fields. We propose that charged impurities are
responsible for an enhancement of such inter-Landau level transition rate and
cause small breakdown currents.Comment: 14 pages, 9 figure
Field survey of alternative seeding methods of canola under extreme wet weather conditions in southeast Saskatchewan, 2011
Non-Peer Reviewe
Cancelled Utility and Traditional Ratemaking Theories: Are Either Used and Useful
This Comment reviews and analyzes recent regulatory proceedings and decisions on cancelled plant losses and the means by which regulatory agencies have attempted to apply traditional ratemaking theories to allocate the losses between ratepayers and shareholders. The author provides a background on the investor owned electric utility industry and its regulatory aspects, as well as some of the ratemaking theories. The author concludes by providing recommendations for improving the application of traditional ratemaking theories to cancelled plant losses
Development and fabrication of insulator seals for thermionic diodes
Eight different types of cermet seals for thermionic diodes were investigated: (1) 1 micron Al2O3 with Nb spheres; (2) 200 A Al2O3 with Nb spheres; (3) 1 micron Al2O3 with Nb 1% Zr spheres; (4) 200 A Al2O3 with Nb 1% Zr spheres; (5) Pure Y2O3 with Nb 1% Zr spheres; (6) Y2O3 3% ZrO2 with Nb 1% Zr spheres; (7) Y2O3 10% ZrO2 with Nb 1% Zr spheres; and (8) ZrO2 12% Y2O3 with Nb 1% Zr spheres. Investigations were made to determine the most favorable fabrication techniques and the effect of the bonding cycle, (length of bonding time and shutdown sequences). The analysis of the seals included tensile test, vacuum test, electrical test and metallurgical examination. At the conclusion of the development phase, 36 seals were fabricated for delivery for evaluation
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