Inertial effects in three dimensional spinodal decomposition of a symmetric binary fluid mixture: A lattice Boltzmann study

The late-stage demixing following spinodal decomposition of a three-dimensional symmetric binary fluid mixture is studied numerically, using a thermodynamicaly consistent lattice Boltzmann method. We combine results from simulations with different numerical parameters to obtain an unprecendented range of length and time scales when expressed in reduced physical units. Using eight large (256^3) runs, the resulting composite graph of reduced domain size l against reduced time t covers 1 < l < 10^5, 10 < t < 10^8. Our data is consistent with the dynamical scaling hypothesis, that l(t) is a universal scaling curve. We give the first detailed statistical analysis of fluid motion, rather than just domain evolution, in simulations of this kind, and introduce scaling plots for several quantities derived from the fluid velocity and velocity gradient fields.Comment: 49 pages, latex, J. Fluid Mech. style, 48 embedded eps figs plus 6 colour jpegs for Fig 10 on p.2

Fair value versus historic cost Valuation for Biological assets: Implications for the quality of financial information

This research finds neither significant differences in earnings and revenues for farms using fair value (FV) for biological assets with respect to those valuing at historic cost (HC), nor an increase in their volatility. It does not bring about differences in profitability, accounting manipulation and farm cash flows predictability either. On the contrary, most tests reveal higher predictive power of future earnings under FV. The study also provides evidence on flawed HC accounting practices in the agricultural sector and concludes that FV seems an interesting tool for the predominant small holdings in the agricultural sector in the European Union.accounting relevance, historic cost, agricultural accounting, prediction, fair value, earnings, cash flow prediction, biological assets

Evolutionary dynamics, intrinsic noise and cycles of co-operation

We use analytical techniques based on an expansion in the inverse system size to study the stochastic evolutionary dynamics of finite populations of players interacting in a repeated prisoner's dilemma game. We show that a mechanism of amplification of demographic noise can give rise to coherent oscillations in parameter regimes where deterministic descriptions converge to fixed points with complex eigenvalues. These quasi-cycles between co-operation and defection have previously been observed in computer simulations; here we provide a systematic and comprehensive analytical characterization of their properties. We are able to predict their power spectra as a function of the mutation rate and other model parameters, and to compare the relative magnitude of the cycles induced by different types of underlying microscopic dynamics. We also extend our analysis to the iterated prisoner's dilemma game with a win-stay lose-shift strategy, appropriate in situations where players are subject to errors of the trembling-hand type.Comment: 14 pages, 12 figures, accepted for publication by Phys. Rev.

Complex rift geometries resulting from inheritance of pre-existing structures: Insights and regional implications from the Barmer Basin rift

Structural studies of the Barmer Basin in Rajasthan, northwest India, demonstrate the important effect that pre-existing faults can have on the geometries of evolving fault systems at both the outcrop and basin-scale. Outcrop exposures on opposing rift margins reveal two distinct, non-coaxial extensional events. On the eastern rift margin northwest–southeast extension was accommodated on southwest- and west-striking faults that form a complex, zig-zag fault network. On the western rift margin northeast–southwest extension was accommodated on northwest-striking faults that form classical extensional geometries. Combining these outcrop studies with subsurface interpretations demonstrates that northwest–southeast extension preceded northeast–southwest extension. Structures active during the early, previously unrecognised extensional event were variably incorporated into the evolving fault systems during the second. In the study area, an inherited rift-oblique fault transferred extension from the rift margin to a mid-rift fault, rather than linking rift margin fault systems directly. The resultant rift margin accommodation structure has important implications for early sediment routing and depocentre evolution, as well as wider reaching implications for the evolution of the rift basin and West Indian Rift System. The discovery of early rifting in the Barmer Basin supports that extension along the West Indian Rift System was long-lived, multi-event, and likely resulted from far-field plate reorganisations

Ludwig: A parallel Lattice-Boltzmann code for complex fluids

This paper describes `Ludwig', a versatile code for the simulation of Lattice-Boltzmann (LB) models in 3-D on cubic lattices. In fact `Ludwig' is not a single code, but a set of codes that share certain common routines, such as I/O and communications. If `Ludwig' is used as intended, a variety of complex fluid models with different equilibrium free energies are simple to code, so that the user may concentrate on the physics of the problem, rather than on parallel computing issues. Thus far, `Ludwig''s main application has been to symmetric binary fluid mixtures. We first explain the philosophy and structure of `Ludwig' which is argued to be a very effective way of developing large codes for academic consortia. Next we elaborate on some parallel implementation issues such as parallel I/O, and the use of MPI to achieve full portability and good efficiency on both MPP and SMP systems. Finally, we describe how to implement generic solid boundaries, and look in detail at the particular case of a symmetric binary fluid mixture near a solid wall. We present a novel scheme for the thermodynamically consistent simulation of wetting phenomena, in the presence of static and moving solid boundaries, and check its performance.Comment: Submitted to Computer Physics Communication

Support amongst UK pig farmers and agricultural stakeholders for the use of food losses in animal feed.

While food losses (foods which were intended for human consumption, but which ultimately are not directly eaten by people) have been included in animal feed for millennia, the practice is all but banned in the European Union. Amid recent calls to promote a circular economy, we conducted a survey of pig farmers (n = 82) and other agricultural stakeholders (n = 81) at a UK agricultural trade fair on their attitudes toward the use of food losses in pig feed, and the potential relegalisation of swill (the use of cooked food losses as feed). While most respondents found the use of feeds containing animal by-products or with the potential for intra-species recycling (i.e. pigs eating pork products) to be less acceptable than feeds without, we found strong support (>75%) for the relegalisation of swill among both pig farmers and other stakeholders. We fit multi-hierarchical Bayesian models to understand people's position on the relegalisation of swill, finding that respondents who were concerned about disease control and the perception of the pork industry supported relegalisation less, while people who were concerned with farm financial performance and efficiency or who thought that swill would benefit the environment and reduce trade-deficits, were more supportive. Our results provide a baseline estimate of support amongst the large-scale pig industry for the relegalisation of swill, and suggest that proponents for its relegalisation must address concerns about disease control and the consumer acceptance of swill-fed pork

An investigation into the prevalence of non-tripod pengrip and its implications for secondary school writers

This research addresses the twin issues of whether non-tripod grips are becoming more common and whether young people who adopt any of these grips experience greater problems than their peers. Existing research into writing grip focuses on young children, leaving the long-term consequences of an unorthodox grip poorly reported. The initial demographic survey investigated changes in penhold. The survey was conducted in a single secondary school, its satellite primary schools and adults in West Wales. This established a high frequency of non-tripod grips occurred among children and young adults that were not replicated in older adults. Statistical analysis of the data indicates that this change in grip happened quite abruptly to young people who began school in the early 1980s. The research also identified ninety-three secondary school pupils, using a range of non-tripod grips and matched each to a pupil using an orthodox grip. Thirteen non-tripod grips were identified, three for the first time, while the severity of others appears greater than in the existing literature. The effects of each grip were considered statistically, using the null hypothesis that groups of matched pupils sharing a grip, will have similar characteristics. Several consequences of the different grips were established, some of which can adversely affect performance and attitudes. These consequences include high levels of pain after even very short writing periods, a high number of adjustments needed to maintain writing, as well as different writing speeds, some of which fall below generally accepted norms. There is thus support for the initial hypothesis that those using non-tripod grips are affected by their choice of grip, which may negatively affect their education. This research ascertained, for the first time, the suitability of a range of unorthodox grips for the demanding writing tasks required by secondary schooling. It also identifies some grips that should be avoided if unnecessary difficulties with writing are to be prevented

Entropy-induced smectic phases in rod-coil copolymers

We present a self-consistent field theory (SCFT) of semiflexible (wormlike) diblock copolymers, each consisting of a rigid and a flexible part. The segments of the polymers are otherwise identical, in particular with regard to their interactions, which are taken to be of an Onsager excluded-volume type. The theory is developed in a general three-dimensional form, as well as in a simpler one-dimensional version. Using the latter, we demonstrate that the theory predicts the formation of a partial-bilayer smectic-A phase in this system, as shown by profiles of the local density and orientational distribution functions. The phase diagram of the system, which includes the isotropic and nematic phases, is obtained in terms of the mean density and rigid-rod fraction of each molecule. The nematic-smectic transition is found to be second order. Since the smectic phase is induced solely by the difference in the rigidities, the onset of smectic ordering is shown to be an entropic effect and therefore does not have to rely on additional Flory-Huggins-type repulsive interactions between unlike chain segments. These findings are compared with other recent SCFT studies of similar copolymer models and with computer simulations of several molecular models.Comment: 13 pages, 8 figure