Putting time into proof outlines

A logic for reasoning about timing of concurrent programs is presented. The logic is based on proof outlines and can handle maximal parallelism as well as resource-constrained execution environments. The correctness proof for a mutual exclusion protocol that uses execution timings in a subtle way illustrates the logic in action

Non-Gatherable Triples for Non-Affine Root Systems

This paper contains a complete description of minimal non-gatherable triangle triples in the lambda-sequences for the classical root systems, $F_4$ and $E_6$. Such sequences are associated with reduced decompositions (words) in affine and non-affine Weyl groups. The existence of the non-gatherable triples is a combinatorial obstacle for using the technique of intertwiners for an explicit description of the irreducible representations of the (double) affine Hecke algebras, complementary to their algebraic-geometric theory.Comment: This is a contribution to the Special Issue on Kac-Moody Algebras and Applications, published in SIGMA (Symmetry, Integrability and Geometry: Methods and Applications) at http://www.emis.de/journals/SIGMA

On the combinatorics of minimal non-gatherable triples in classical affine root systems

Minimal non-gatherable triples are combinatorially interesting objects found in the inversion sets of words in some affinne and non-afiine Weyl groups. This dissertation continues the work of our two papers with professor Cherednik. The goal of this paper is the complete description of minimal non-gatherable triangle triples in the lambda-sequences for the ane classical root systems. After a brief introduction, we will accomplish this by describing all such objects in the twisted B-case and showing how that case extends to cases C and D

Effect of Wood Characteristics on Pressure Responses During Supercritical Carbon Dioxide Treatment

The potential for using the anatomical properties of wood to predict response to supercritical fluid impregnation was investigated using an array of hardwood and softwood species. Longitudinal resin canals were a reasonable predictor of softwood response to pressure application, while radial gas permeability and/or fiber dimensions were useful for the same predictions in hardwoods. Most other anatomical characteristics were poorly correlated with pressure response. The results suggest that there is some ability to use limited anatomical measurements to predict the receptivity of a given species to supercritical fluid impregnation, thereby reducing the need for iterative treatment trials to assess suitability of a species for use in this process

Internal Pressure Measurement Techniques and Pressure Response in Wood During Treating Processes

The development of pressure inside wood during preservative impregnation was studied using Douglas-fir heartwood and ponderosa pine sapwood. Pressure sensors mounted on sample holders provided the most reliable measurements. As expected, pressure equilibrated most rapidly with air as the treatment medium and ponderosa pine as the test species. Pressure changes were relatively slow in Douglas-fir heartwood, suggesting that process conditions involving relatively rapid changes in pressure conditions will have little effect on fluid penetration away from the wood surface

Proposal for Higgs and Superpartner Searches at the LHCb Experiment

The spectrum of supersymmetric theories with R-parity violation are much more weakly constrained than that of supersymmetric theories with a stable neutralino. We investigate the signatures of supersymmetry at the LHCb experiment in the region of parameter space where the neutralino decay leaves a displaced vertex. We find sensitivity to squark production up to squark masses of order 1 TeV. We note that if the Higgs decays to neutralinos in this scenario, LHCb should see the lightest Higgs boson before ATLAS and CMS.Comment: 7 pages, 5 figure

Internal Pressure Development During Supercritical Fluid Impregnation of Wood

Supercritical fluid impregnation has tremendous potential for effectively impregnating a variety of species, but little is known about the pressure response in wood during this process. Pressure response was studied in a number of wood species using specially designed high pressure probes, which allowed in-situ monitoring of the treatment process. Pressure response was relatively rapid in permeable species such as pine, but tended to lag in less permeable species. In some cases, the differences between surface and internal pressure exceeded the material properties of the wood, and crushing or fractures resulted. The results indicate that the rates of pressure application and release can be tailored to control pressure differentials to avoid wood damage

Swelling of a Cell Lumen Filled and A Cell-Wall Bulked Wood Polymer Composite in Water

Liquid water swelling of lumen-filled and cell-wall bulked wood polymer composite (WPC) samples was measured at room temperature and 80 C. Ultimate swelling was greater (approximately that of untreated wood) and moisture diffusion coefficient lower for the lumen filled wood. The higher density, lumen filled sample had lower swelling than the lower density one. At 80 C, fiber saturation points (FSP) were 8% for the cell-wall samples and above 20% for the cell lumen samples. The FSP for more highly loaded cell lumen samples was lower than that for lower loading

Metodologia para previsão de propagação de trincas aplicada a um navio tanque

TCC (graduação) - Universidade Federal de Santa Catarina. Campus Joinville. Engenharia Naval.Este trabalho apresenta uma proposta de metodologia baseada nos conceitos da mecânica da fratura linear elástica, a qual prevê a propagação de trincas sob a ação de fadiga em materiais dúcteis, como o aço ASTM A36 utilizado no casco de navios. A metodologia apresentada é resultado de um levantamento bibliográfico das teorias de mecânica geral para que seja aplicado à área naval. A sequência matemática resultante é baseada nas teorias de energia associadas à uma trinca pré-existente sugerida por Griffith (1921) aplicada à Lei de Paris (1961) que relaciona a taxa de propagação do tamanho da trinca decorrente da variação de tensão com o número de ciclos até chegar a um determinado tamanho crítico. É aplicado na tensão do navio um fator de correção devido ao encruamento decorrente no material que torna a região plástica. Além da possibilidade da previsão da vida residual em fadiga para componentes que contenham defeitos já no estágio de propagação, também há a possibilidade de estimar a amplitude máxima da tensão aplicada para que o componente apresente uma durabilidade mínima desejada em fadiga. Para a demonstração da aplicação da metodologia proposta na área naval utilizou-se como modelo um navio de carga. As sociedades classificadoras disponibilizam equações empíricas baseadas em convenções e normas para o cálculo dos momentos de flexão que as ondas geram nos navios, e desta forma pode-se prever as tensões às quais o navio estará submetido quando em navegação. Em suma, com o desenvolvimento deste trabalho, espera-se contribuir com um modelo matemático que permita prever o desempenho de trincas sob a ação de fadiga