19,126 research outputs found
Pilot Survey – Queue Management Strategies for Urban Traffic Control Systems
BACKGROUND
1.1 Advances in traffic signal optimization have produced increases in the capacity of urban road networks, but recent growth in demand has meant that many junctions operate at or above saturation levels. Delay costs increase dramatically when queues extend to block upstream junctions and queue management strategies are now required to ensure that local traffic signals operate effectively when oversaturated conditions occur.
1.2 The aims of this SERC-funded "Queue Management Strategies" project are as follows:
(a) To generalise the strategies for queue management that were developed and tested empirically in Bangkok (See ITS WP 249 and WP 251);
(b) To develop a computer graphics model to represent queue propagation;
(c) To test the strategies' applicability and performance in UK networks;
(d) To investigate their incorporation into standard signal optimization programs
'A quaint and unimportant anachronism'? The office of Governor General and constitutional controversies in the Commonwealth Caribbean
This chapter takes as its starting point D. A. Low’s Appendix in his 1988 edited volume Constitutional Heads and Political Crises. Low’s Appendix lists a series of constitutional ‘episodes’ in the Commonwealth, defined, by his criteria, as instances in which ‘constitutional heads … became significantly involved in some constitutional and/or political crisis’; took actions which ‘entailed important political consequences’; and/or took ‘a public politico-constitutional decision of some … moment [acting] … in his [or her] own deliberate judgement’. Focusing on the Commonwealth Caribbean, this chapter seeks to extend Low’s Appendix in two ways: (1) analysing constitutional episodes in the Commonwealth Caribbean in the period 1945–1987 that are notably missing from Low’s Appendix; and (2) extending the time frame to examine constitutional ‘episodes’ in the Caribbean between 1987 and the present day. The relative frequency of such episodes in the later period runs contrary to the general assumption of constitutional stability and the smooth functioning of Westminster governance in the region. This chapter presents a preliminary typology of constitutional episodes in the Caribbean, before reflecting on the wider implications of these episodes for governance in the region. It argues that the problems typically associated with the Westminster system in the Caribbean—e.g. partisanship, winner takes all politics, prime ministerial dominance—usually studied in the sphere of the executive and the legislature—are replicated at the level of the constitutional Head of State
The Invincible (1758) site: an integrated geophysical assessment
Chirp sub-bottom profiler and repeat sidescan sonar imaging of the Invincible wreck site (1758) in the Solent (U.K.), interpretation, and implications for management of the site
Flavor altering excitations of composite fermions
Past theoretical studies have considered excitations of a given flavor of
composite fermions across composite-fermion quasi-Landau levels. We show that
in general there exists a ladder of flavor changing excitations in which
composite fermions shed none, some, or all of their vortices. The lowest energy
excitations are obtained when the composite fermions do not change their
flavor, whereas in the highest energy excitations they are stripped of all of
their vortices, emerging as electrons in the final state. The results are
relevant to the intriguing experimental discovery of Hirjibehedin {\em et al.}
(cond-mat/0306152) of coexisting excitation modes of composite fermions of
different flavor in the filling factor range .Comment: 5 pages, 4 figure
The effect of leveling coatings on the atomic oxygen durability of solar concentrator surfaces
Space power systems for Space Station Freedom will be exposed to the harsh environment of low earth orbit (LEO). Neutral atomic oxygen is the major constituent in LEO and has the potential of severely reducing the efficiency of solar dynamic power systems through degradation of the concentrator surfaces. Several transparent dielectric thin films have been found to provide atomic oxygen protection, but atomic oxygen undercutting at inherent defect sites is still a threat to solar dynamic power system survivability. Leveling coatings smooth microscopically rough surfaces, thus eliminating potential defect sites prone to oxidation attack on concentrator surfaces. The ability of leveling coatings to improve the atomic oxygen durability of concentrator surfaces was investigated. The application of a EPO-TEK 377 epoxy leveling coating on a graphite epoxy substrate resulted in an increase in solar specular reflectance, a decrease in the atomic oxygen defect density by an order of magnitude and a corresponding order of magnitude decrease in the percent loss of specular reflectance during atomic oxygen plasma ashing
Fermions out of Dipolar Bosons in the lowest Landau level
In the limit of very fast rotation atomic Bose-Einstein condensates may
reside entirely in the lowest two-dimensional Landau level (LLL). For small
enough filling factor of the LLL, one may have formation of fractional quantum
Hall states. We investigate the case of bosons with dipolar interactions as may
be realized with Chromium-52 atoms. We show that at filling factor equal to
unity the ground state is a Moore-Read (a.k.a Pfaffian) paired state as is the
case of bosons with purely s-wave scattering interactions. This Pfaffian state
is destabilized when the interaction in the s-wave channel is small enough and
the ground state is a stripe phase with unidimensional density modulation. For
filling factor 1/3, we show that there is formation of a Fermi sea of
``composite fermions''. These composites are made of one boson bound with three
vortices. This phase has a wide range of stability and the effective mass of
the fermions depends essentially only of the scattering amplitude in momentum
channels larger or equal to 2. The formation of such a Fermi sea opens up a new
possible route to detection of the quantum Hall correlations.Comment: 12 pages, 5 figures, published versio
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A structure property investigation of a multi-component polyacrylate photoresist/
The multi-component acrylate photoresist investigated in this dissertation consists of a linear polyacrylate copolymer, a photo-polymerizable multi-functional acrylate monomer, a ketone photo-initiator, an amine crosslinking agent and a certain amount of inorganic filler. Three distinct phases have been observed in this multi-component system by transmission electron microscopy (TEM)--the flake-like inorganic filler, the monomer-rich droplet inclusion and the polymer-rich matrix. Selected area diffraction (SAD) has determined the crystalline structure of the filler phase and the amorphous structure of the matrix phase. It has also concluded that the diffraction rings in the monomer-rich inclusion phase come from the filler polycrystals. After the photoresist is fully cured by UV radiation followed by thermal baking, distinct spots in the dimension of 100 A have been observed in the monomer-rich inclusion phase. The subsequent thermal curing process increases the mobility of the molecules and provides sufficient time for the molecules to aggregate and form distinct micro-phases in the monomer-rich inclusions. In the mean time, the filler crystals grow larger and distinct diffraction rings and spots can be seen in the SAD pattern. In contrast to the phase-separate morphology of the multi-component photoresist, only one broad glass transition has been observed by DSC, DMA and dielectric relaxation experiments. The broad glass transition reflects the inhomogeneity of local composition and the heterogeneous network structure of the material. The structure-property relationship of the multi-component photoresist as a function of curing history has been investigated. The residual stress and mechanical properties of the acrylate photoresist processed under various curing conditions have been characterized, and the curing mechanism has also been investigated. The increased glass transition temperature, modulus and ultimate strength of the material indicate that either ultraviolet radiation or thermal baking partially cures the photoresist. However, FTIR studies suggest that the two curing methods generate different network structures through independent crosslinking mechanisms. Both curing methods are required to fully cure the acrylate photoresist and achieve the desired coating properties. It has been found that the curing sequence plays an important role in determining the final network structure and material properties of the thermoset coating. (Abstract shortened by UMI.
Resisting Neoliberalism: The challenge of activist librarianship in English Higher Education
Purpose
The purpose of this paper is to examine the political position of academic librarianship in the context of recent changes in English Higher Education. The neoliberalisation of academic librarianship, both as an academic discipline and profession, is considered. The emergence of the Radical Librarians Collective is examined as a potential site through which to counter these developments and foster radical alternatives.
Design/methodology/approach
The paper draws upon Gramsci’s concepts of hegemony and praxis, and post-structural critiques of neoliberalism, as a theoretical framework to guide data collection and analysis, and observe developments within academic librarianship vis-à -vis broader processes of neoliberalisation. Empirical data collected through interviews and participant observation are analysed using thematic and critical discourse analysis.
Findings
The research finds that academic librarianship as a discipline and practice is undergoing a process of neoliberalisation. An umbrella organisation of activist librarians, Radical Librarians Collective, is found to be resisting these developments and has some potential to become a space through which radical alternatives to neoliberal hegemony can be explored and fostered.
Research limitations/implications
The research demonstrates the utility of a Gramscian theoretical framework as a lens through which to observe developments in the field of library and information studies (LIS). Further empirical work would deepen the authors’ understanding of such developments across a range of institutions and locales.
Originality/value
The research makes an original contribution to critical research on the struggles around the neoliberalisation of academic librarianship in the UK. The theoretically informed analysis provides original insights into these processes, and makes a methodological contribution to LIS research
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