33,979 research outputs found
Rotational and vibrational nonequilibrium effects in rarefied, hypersonic flow
Results are reported for an investigation into the methods by which energy transfer is calculated in the Direct Simulation Monte Carlo method. Description is made of a recently developed energy exchange model that deals with the translational and rotational modes. A new model for simulating the transfer of energy between the translational and vibrational modes is also explained. This model allows the vibrational relaxation time to follow the temperature dependence predicted by the Landau-Teller theory at moderate temperatures. For temperatures in excess of about 8000K the vibrational model is extended to include an empirical result for the relaxation time. The effect of introducing these temperature dependent collision numbers into the DSMC technique is assessed by making calculations representative of the stagnation streamline of a hypersonic space vehicle. Both thermal and chemical nonequilibrium effects are included while the flow conditions have been chosen such that ionization and radiation may be neglected. The introduction of these new models is found to significantly affect the degree of thermal nonequilibrium observed in the flowfield. Larger, and more widely ranging, differences in the results obtained with the different energy exchange probabilities are found when a significant amount of internal energy is included in the calculation of chemical nonequilibrium
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Participatory action research in the development and delivery of self-harm awareness sessions in prison: involving service users in staff development
Flow boiling with enhancement devices for cold plate coolant channel design
A research program to study the effect of enhancement devices on flow boiling heat transfer in coolant channels, which are heated either from the top side or uniformly, is discussed. Freon 11 is the working fluid involved. The specific objectives are: (1) examine the variations in both the mean and local (axial and circumferential) heat transfer coefficients for a circular coolant channel with either smooth walls or with both a twisted tape and spiral finned walls, (2) examine the effect channel diameter (and the length-to-diameter aspect ratio) variations for the smooth wall channel, and (3) develop an improved data reduction analysis
Finding hope within hopelessness: an exploration of critical dystopiaand its use in modern video games
Since the term ‘critical dystopia’ was first conceptualised and explored by academics in utopianism studies, including Tom Moylan and Rafaella Baccolini, there has been little research undertaken to exemplify how the form has been utilised in modern screen culture; mostly involving studies based on analysis of literature and cinematic texts rather than all facets of visual art and media.
This dissertation aims to not only showcase the theoretical framework surrounding critical dystopia in comparison to its classical form, but to provide insight in to how its use in modern video gaming has proliferated whilst inheriting narrative and aesthetical traits traditionally associated with its literary and cinematic counterparts.
This essay also argues that the integration of gameplay dynamics alongside narrative aspects further contributes to them being defined as such and provides a unique way to engage with discussions of world issues; including the integration of morality-based choice making, interactive narratives and a deep level of player immersion through use of realistic physics, sound, graphics and mechanics such as in-game construction. These elements aid in creating a personalised and multi-faceted approach to understanding the implied dystopia, and any utopian impulse or hope for positive progression beyond it
Fitting Jump Models
We describe a new framework for fitting jump models to a sequence of data.
The key idea is to alternate between minimizing a loss function to fit multiple
model parameters, and minimizing a discrete loss function to determine which
set of model parameters is active at each data point. The framework is quite
general and encompasses popular classes of models, such as hidden Markov models
and piecewise affine models. The shape of the chosen loss functions to minimize
determine the shape of the resulting jump model.Comment: Accepted for publication in Automatic
Supersonic quantum communication
When locally exciting a quantum lattice model, the excitation will propagate
through the lattice. The effect is responsible for a wealth of non-equilibrium
phenomena, and has been exploited to transmit quantum information through spin
chains. It is a commonly expressed belief that for local Hamiltonians, any such
propagation happens at a finite "speed of sound". Indeed, the Lieb-Robinson
theorem states that in spin models, all effects caused by a perturbation are
limited to a causal cone defined by a constant speed, up to exponentially small
corrections. In this work we show that for translationally invariant bosonic
models with nearest-neighbor interactions, this belief is incorrect: We prove
that one can encounter excitations which accelerate under the natural dynamics
of the lattice and allow for reliable transmission of information faster than
any finite speed of sound. The effect is only limited by the model's range of
validity (eventually by relativity). It also implies that in non-equilibrium
dynamics of strongly correlated bosonic models far-away regions may become
quickly entangled, suggesting that their simulation may be much harder than
that of spin chains even in the low energy sector.Comment: 4+3 pages, 1 figure, some material added, typographic error fixe
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