2,873 research outputs found
Solution Processable Carbon-Based Electronics
Fabricating electronic devices using solution-based processing methods opens up a broad
range of potential applications that are inaccessible to conventional semiconductor fabrication
technologies. The chemically diverse family of carbon-based materials are suitable for
this purpose with almost limitless possibilities for molecular tailoring. The present work
is a study of some of the materials for and device physics of field-effect transistors based
on solution processable layers. Each aspect of this work is chosen to address a current
difficulty in the development solution-processable carbon-based electronics.
For portable and battery-powered applications, low-power circuits are required. This
can be achieved by using a complementary logic circuit architecture (that requires both
electron and hole transporting semiconductors) where the discrete devices operate at low
voltages. Practically, this requires a high capacitance gate dielectric which is compatible
with solution processing of a range of semiconductor materials. One family of molecules
suitable for this purpose are self-assembling phosphonic acids that can form molecular
monolayers. In the present study, molecular tailoring of this family of molecules is investigated
as a route towards improving the compatibility of these dielectrics with solution
processed semiconductors.
One of the difficulties with utilising a complementary logic circuit architecture is the
requirement of a suitable electron transporting semiconductor. This semiconductor must
be solution-processable, exhibit a high electron mobility and be stable against degradation
upon atmospheric exposure. Although many p-channel semiconductors fulfil these
requirements, equivalent performance in many families of n-channel semiconductors remains
challenging. In the present study, the use of fullerenes, a widely used family of
semiconductors, is explored for implementation as an n-channel material in field-effect
transistors. Their electronic structure is controlled by chemical tailoring of each molecule
and the impact of this parameter variation on the air-stability of these fullerenes is assessed.
Graphene, potentially one of the most important materials for future electronics, is
currently impractical to prepare over large areas. Chemical derivation routes are sought
which allow processing of graphene from solution. One of the most important routes
is solution phase exfoliation of graphene oxide followed by thermal or chemical reduction.
Unfortunately this introduces a high density of defects within the final graphene
layer which ultimately limits the charge-carrier mobility. Here, a milder oxidation with
surfactant-assisted solution phase exfoliation is investigated as a route to improving the
quality of graphene films following reduction. The electronic properties of thin- films of
these chemically-derived graphene layers are explored as the active layer in field-effect
transistors
A polynomial-time reduction from the multi-graph isomorphism problem to additive codeequivalence
We present a polynomial-time reduction from the multi-graph isomorphism problem to the problem of code equivalence of additive codes over finite extensions of the field with two elements.Peer ReviewedPostprint (published version
The equivalence of linear codes implies semi-linear equivalence
The version of record is available online at: 10.1007/s10623-022-01055-xWe prove that if two linear codes are equivalent then they are semi-linearly equivalent. We also prove that if two additive MDS codes over a field are equivalent then they are additively equivalent.Peer ReviewedPostprint (author's final draft
Unpacking the foundational dimensions of work integration social enterprise: the development of an assessment tool
Purpose
The aim of this exploratory, mixed methods study was to develop and test a tool that identifies foundational dimensions of work integration social enterprises (WISEs) for use in empirical studies and enterprise self-assessment. Construction of the initial prototype was based upon a review of the literature and prior qualitative research by the authors.
Design/methodology/approach
A 20-item question pool with a four-point response scale was constructed to explore WISE business and employment practices and strategies for worker growth and development. Three sequential field tests were conducted with the prototype – the first with 5 Canadian WISEs, the second with 14 WISEs in the UK and the third with 6 Canadian WISEs involved in an outcome study in the mental health sector. Each field test included completion of the questionnaire by persons with managerial responsibility within the WISE and evaluative feedback captured through questions on the applicability and interpretability of the items.
Findings
Testing of the prototype instrument revealed the inherent diversity in the field and the difficulty in creating questions that both embrace that diversity and produce unidimensional variables definable along a spectrum. A number of challenges with question structure were identified and have been modified throughout the iterative testing process.
Research limitations/implications
This study identified central domains for inclusion in a multi-dimensional WISE assessment tool. Further testing will help further refine scaling and establish psychometric properties.
Originality/value
This measure will provide a descriptive profile of WISEs across sectors and identify WISE core dimensions for research and organizational development.
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A Constrained Sequential-Lamination Algorithm for the Simulation of Sub-Grid Microstructure in Martensitic Materials
We present a practical algorithm for partially relaxing multiwell energy
densities such as pertain to materials undergoing martensitic phase
transitions. The algorithm is based on sequential lamination, but the evolution
of the microstructure during a deformation process is required to satisfy a
continuity constraint, in the sense that the new microstructure should be
reachable from the preceding one by a combination of branching and pruning
operations. All microstructures generated by the algorithm are in static and
configurational equilibrium. Owing to the continuity constrained imposed upon
the microstructural evolution, the predicted material behavior may be
path-dependent and exhibit hysteresis. In cases in which there is a strict
separation of micro and macrostructural lengthscales, the proposed relaxation
algorithm may effectively be integrated into macroscopic finite-element
calculations at the subgrid level. We demonstrate this aspect of the algorithm
by means of a numerical example concerned with the indentation of an Cu-Al-Ni
shape memory alloy by a spherical indenter.Comment: 27 pages with 9 figures. To appear in: Computer Methods in Applied
Mechanics and Engineering. New version incorporates minor revisions from
revie
Andrew Melville, sacred chronology and world history: the Carmina Danielis 9 and the Antichristus
The accepted view of the ecclesiastical reformer Andrew Melville (1545–1622) as the dynamic leader of the Presbyterian movement in Jacobean Scotland has been severely eroded in recent years, with particular criticism of the actual importance of his contribution to the Kirk and to Scottish higher education. While this reductionism has been necessary, it has resulted in an inversion of the overwhelmingly positive traditional image of Melville, and does not give us a rounded assessment of his life and works. This article attempts to partially redress this balance by looking at a neglected aspect of Melville's Latin writings, which showcase his talents as a humanist intellectual and biblical commentator. It focuses on two long poems that are both commentaries and paraphrases of Daniel and Revelation: the Carmina Danielis and the Antichristus. Through these poems, we see how Melville engaged with two problems exercising reformed theologians across Europe: the dating of key biblical events and the historicised meaning of prophecies within these texts. We also find evidence that Melville read widely among both contemporary and ancient commentators on both these issues
Burrowing owls, Pulex irritans and plague
Western burrowing owls (Athene cunicularia hypugaea) are small, ground-dwelling owls ofwestern North America that frequent prairie dog (Cynomys spp.) towns and other grasslands.As they rely on rodent prey and occupy burrows once or concurrently inhabited by fossorialmammals, the owls often harbor fleas. We examined the potential role of fleas found onburrowing owls in plague dynamics by evaluating prevalence of Yersinia pestis in fleas and inowl blood. During 2012-2013 fleas and blood were collected from burrowing owls in portionsof five states with endemic plague: Idaho, Oregon, Washington, Colorado, and South Dakota.Fleas were enumerated, taxonomically identified, pooled by nest and assayed for Y. pestis usingculturing and molecular (PCR) approaches. Owl blood underwent serological analysis for plagueantibodies and nested PCR for detection of Y. pestis. Of \u3e4750 fleas collected from owls, Pulexirritans, a known plague vector in portions of its range, comprised more than 99.4%. However,diagnostic tests for Y. pestis of flea pools (culturing and PCR) and owl blood (PCR and serology)were negative. Thus, despite that fleas were prevalent on burrowing owls, and the potentialfor a relationship with burrowing owls as a phoretic host of infected fleas exists, we found noevidence of Y. pestis in sampled fleas or in owls that harbored them. We suggest that studiessimilar to those reported here during plague epizootics will be especially useful for confirmingthese results
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The characteristics of cognitive neuroscience tests in a schizophrenia cognition clinical trial: Psychometric properties and correlations with standard measures.
In comparison to batteries of standard neuropsychological tests, cognitive neuroscience tests may offer a more specific assessment of discrete neurobiological processes that may be aberrant in schizophrenia. However, more information regarding psychometric properties and correlations with standard neuropsychological tests and functional measures is warranted to establish their validity as treatment outcome measures. The N-back and AX-Continuous Performance Task (AX-CPT) are two promising cognitive neuroscience tests designed to measure specific components of working memory and contextual processing respectively. In the current study, we report the psychometric properties of multiple outcome measures from these two tests as well as their correlations with standard neuropsychological measures and functional capacity measures. The results suggest that while the AX-CPT and N-back display favorable psychometric properties, they do not exhibit greater sensitivity or specificity with functional measures than standard neurocognitive tests
Approaches for advancing scientific understanding of macrosystems
The emergence of macrosystems ecology (MSE), which focuses on regional- to continental-scale ecological patterns and processes, builds upon a history of long-term and broad-scale studies in ecology. Scientists face the difficulty of integrating the many elements that make up macrosystems, which consist of hierarchical processes at interacting spatial and temporal scales. Researchers must also identify the most relevant scales and variables to be considered, the required data resources, and the appropriate study design to provide the proper inferences. The large volumes of multi-thematic data often associated with macrosystem studies typically require validation, standardization, and assimilation. Finally, analytical approaches need to describe how cross-scale and hierarchical dynamics and interactions relate to macroscale phenomena. Here, we elaborate on some key methodological challenges of MSE research and discuss existing and novel approaches to meet them
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