Journal for the history of analytical philosophy: Gilbert Ryle: intelligence, practice, skill, v. 5, no. 5

Special issue on Gilbert Ryle edited by Juliet Floyd and Lydia Patton. Articles: "Volume Introduction: Gilbert Ryle on Propositions, Propositional Attitudes, and Theoretical Knowledge" by Julia Tanney; "Ryle’s “Intellectualist Legend” in Historical Context" by Michael Kremer; "Skill, Drill, and Intelligent Performance: Ryle and Intellectualism" by Stina Bäckström and Martin Gustafsson; "Ryle on the Explanatory Role of Knowledge How"by Will Small.https://jhaponline.org/jhap/issue/view/319Published versio

Einstein boundary conditions for the Einstein equations in the conformal-traceless decomposition

In relation to the BSSN formulation of the Einstein equations, we write down the boundary conditions that result from the vanishing of the projection of the Einstein tensor normally to a timelike hypersurface. Furthermore, by setting up a well-posed system of propagation equations for the constraints, we show explicitly that there are three constraints that are incoming at the boundary surface and that the boundary equations are linearly related to them. This indicates that such boundary conditions play a role in enforcing the propagation of the constraints in the region interior to the boundary. Additionally, we examine the related problem for a strongly hyperbolic first-order reduction of the BSSN equations and determine the characteristic fields that are prescribed by the three boundary conditions, as well as those that are left arbitrary.Comment: 11 page

El perfil de la pobreza en Montevideo 1983 - 1992

In this paper, time series on the extent of poverty in Montevideo (1983-92) are derived and analysed using different measures and approaches in the definition of the poverty line. The results show that the picture of how poverty has developed is much affected by the use of and absolute or relative poverty line. Meanwhile relative poverty is quite stable, the proportion of the population under a poverty line indicating a constant living standard is closely related to GDP. The measures that were used are descomposable. The results show that young persons, especially children are poverty prone and that a high education of the household head means a low risk of becoming poor.

Algorithms for Infeasible Path Calculation

Static Worst-Case Execution Time (WCET) analysis is a technique to derive upper bounds for the execution times of programs. Such bounds are crucial when designing and verifying real-time systems. One key component in static WCET analysis is to derive flow information, such as loop bounds and infeasible paths for the analysed program. Such flow information can be provided as either as annotations by the user, can be automatically calculated by a flow analysis, or by a combination of both. To make the analysis as simple, automatic and safe as possible, this flow information should be calculated automatically with no or very limited user interaction. In this paper we present three novel algorithms to calculate infeasible paths. The algorithms are all designed to be simple and efficient, both in terms of generated flow facts and in analysis running time. The algorithms have been implemented and tested for a set of WCET benchmarks programs

New Insights into Roughness Applications in Tip Vortex Cavitation Inception Mitigation

Tip vortex cavitation (TVC) is usually the first type of cavitation that appears on a propeller. Therefore, it is considered as the main cavitation characteristics to avoid in the design procedure of low-noise propellers, where their operating profiles demand very low radiated noise emissions. The current study includes both numerical and experimental analyses of blade surface roughness application in order to mitigate TVC inception. The investigation consists of applying roughness application on a classical benchmark, an elliptical foil, and on a propeller selected from a Kongs-berg research series of highly skewed propellers having a low effective tip load. The numerical simulations are performed on an appropriate grid resolution for tip vortex propagation, at least 32 cells per vortex diameter by using Implicit Large Eddy Simulation (ILES) for unsteady simulations, and RANS using the SST k − ω model with a curvature correction for steady simulations. Two approaches are considered to include roughness in the numerical simulations: using a rough wall function and resolving the flow around the roughness elements. To minimize the negative effects of the roughness on the propeller performance, the roughness area is optimized by simultaneous consideration of the tip vortex mitigation and performance degradation. Experimental measurements of the elliptical foil are conducted to support the CFD study at different operating conditions and with different roughness patterns while LDV and high-speed video recordings are used to collect the data. The tested conditions include both cavitating and inception of TV flows on the smooth and roughened foil to provide further insights on the usage of roughness. For the elliptical foil, it is found that the application of roughness can reduce the cavitation number for cavitation inception, σ i , by 35 % while keeping the performance degradation less than 1% compared to the smooth foil condition. The average reduction of the TVC inception number achieved by using roughness on the propeller is around 21% with a performance degradation of around 1.5% compared to the smooth propeller condition

Multifluid magnetohydrodynamic turbulent decay

It is generally believed that turbulence has a significant impact on the dynamics and evolution of molecular clouds and the star formation which occurs within them. Non-ideal magnetohydrodynamic effects are known to influence the nature of this turbulence. We present the results of a suite of 512-cubed resolution simulations of the decay of initially super-Alfvenic and supersonic fully multifluid MHD turbulence. We find that ambipolar diffusion increases the rate of decay of the turbulence while the Hall effect has virtually no impact. The decay of the kinetic energy can be fitted as a power-law in time and the exponent is found to be -1.34 for fully multifluid MHD turbulence. The power spectra of density, velocity and magnetic field are all steepened significantly by the inclusion of non-ideal terms. The dominant reason for this steepening is ambipolar diffusion with the Hall effect again playing a minimal role except at short length scales where it creates extra structure in the magnetic field. Interestingly we find that, at least at these resolutions, the majority of the physics of multifluid turbulence can be captured by simply introducing fixed (in time and space) resistive terms into the induction equation without the need for a full multifluid MHD treatment. The velocity dispersion is also examined and, in common with previously published results, it is found not to be power-law in nature.Comment: 16 pages, 15 figures, Accepted for publication in Ap

3D printing tablets: Predicting printability and drug dissolution from rheological data

Rheology is an indispensable tool for formulation development, which when harnessed, can both predict a material’s performance and provide valuable insight regarding the material’s macrostructure. However, rheological characterizations are under-utilized in 3D printing of drug formulations. In this study, viscosity measurements were used to establish a mathematical model for predicting the printability of fused deposition modelling 3D printed tablets (Printlets). The formulations were composed of polycaprolactone (PCL) with different amounts of ciprofloxacin and polyethylene glycol (PEG), and different molecular weights of PEG. With all printing parameters kept constant, both binary and ternary blends were found to extrude at nozzle temperatures of 130, 150 and 170 °C. In contrast PCL was unextrudable at 130 and 150 °C. Three standard rheological models were applied to the experimental viscosity measurements, which revealed an operating viscosity window of between 100 and 1000 Pa·s at the apparent shear rate of the nozzle. The drug release profiles of the printlets were experimentally measured over seven days. As a proof-of-concept, machine learning models were developed to predict the dissolution behaviour from the viscosity measurements. The machine learning models were discovered to accurately predict the dissolution profile, with the highest f2 similarity score value of 90.9 recorded. Therefore, the study demonstrated that using only the viscosity measurements can be employed for the simultaneous high-throughput screening of formulations that are printable and with the desired release profile

Robustness of the Blandford-Znajek mechanism

The Blandford-Znajek mechanism has long been regarded as a key ingredient in models attempting to explain powerful jets in AGNs, quasars, blazzars etc. In such mechanism, energy is extracted from a rotating black hole and dissipated at a load at far distances. In the current work we examine the behaviour of the BZ mechanism with respect to different boundary conditions, revealing the mechanism robustness upon variation of these conditions. Consequently, this work closes a gap in our understanding of this important scenario.Comment: 7 pages, accepted in CQ

Fracture of Laminated Bamboo and the Influence of Preservative Treatments

Treated bamboo can be made into large, durable structural elements which have the potential to become a transformative large-scale building material, but the fracture behaviour which determines their ultimate strength in various loading scenarios has not been studied. Laminated bamboo is a promising structural engineered bamboo material, and is generally made from bamboo treated to improve its durability. Studies into the structural behaviour of laminated bamboo indicate that different preservative treatments affect the structural properties of the composite differently, with conflicting evidence from tests in different load orientations. This study uses fracture mechanical testing and microscopy to develop an understanding of the fracture mechanics of engineered bamboo, and explains why the properties of the composite under tension, compression and bending may be affected differently by the treatment processes. Two types of treated Moso bamboo are studied alongside the same material with minimal processing. The treated material had gone through one of two commercial processes: bathing in a hydrogen peroxide bleach solution, or treatment by pressurised steam (described as caramelised). The results show that the critical strain energy release rate in the caramelised material is much lower than that in the bleached, and the fracture behaviour of the bleached material is closer to that of the raw bamboo. Fracture experiments included Mode I and Mode II fracture with cracks progressing parallel to the grain, and Mode I fracture with a crack progressing perpendicular to the grain. The results shed new light on the strength of structural-size elements