15,227 research outputs found
Negative Linear Compressibility
While all materials reduce their intrinsic volume under hydrostatic (uniform)
compression, a select few actually \emph{expand} along one or more directions
during this process of densification. As rare as it is counterintuitive, such
"negative compressibility" behaviour has application in the design of pressure
sensors, artificial muscles and actuators. The recent discovery of surprisingly
strong and persistent negative compressibility effects in a variety of new
families of materials has ignited the field. Here we review the phenomenology
of negative compressibility in this context of materials diversity, placing
particular emphasis on the common structural motifs that recur amongst known
examples. Our goal is to present a mechanistic understanding of negative
compressibility that will help inform a clear strategy for future materials
design.Comment: Submitted to PCC
Nanostructure determination from the pair distribution function: A parametric study of the INVERT approach
We present a detailed study of the mechanism by which the INVERT method
[Phys. Rev. Lett. 104, 125501] guides structure refinement of disordered
materials. We present a number of different possible implementations of the
central algorithm and explore the question of algorithm weighting. Our analysis
includes quantification of the relative contributions of variance and
fit-to-data terms during structure refinement, which leads us to study the
roles of density fluctuations and configurational jamming in the RMC fitting
process. We present a parametric study of the pair distribution function
solution space for C60, a-Si and a-SiO2, which serves to highlight the
difficulties faced in developing a transferable weighting scheme.Comment: 15 pages, 7 figures, formatted for JPCM (RMC issue
Development of the interactive broiler income spreadsheet
The poultry industry has experienced unprecedented increased efficiencies since 1960 in large part due to vertical integration facilitated by production contracts between growers and integrators. As growers seek information about contract production they need to be well informed about all aspects of the process, especially potential income. Recent poultry grower complaints have surfaced as a result of incorrect expense and revenue expectations. The Interactive Broiler Income Spreadsheet (IBIS) is being developed to enable current and prospective poultry producers to better estimate income. IBIS, an unbiased Excel™ spreadsheet tool to assist in decision making regarding broiler production profitability, uses actual grower expense and revenue information or, alternatively, grower-panel default data to assess income under various growerspecified production, expense, and price scenarios. Poultry integrator grower service personnel, lenders, and Cooperative Extension professionals will utilize IBIS to assist growers in operational planning and risk tolerance identification in varying economic situations. Growers may also gauge effects of capital improvements, equipment upgrades, chick placements, and time between flocks on income. Development of IBIS is continuing with collection of additional data and revision of procedures based upon results of field testing
Initial behavioural and attitudinal responses to influenza A, H1N1 ('swine flu')
Copyright © 2010 by the BMJ Publishing Group Ltd. All rights reserved.This study was sponsored by Canadian Institute of Health Research (CIHR), and
supported by the Community Coalition Concerned about SARS and other community organisations in the great Toronto area
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