Densely distributed and real-time scour hole monitoring using piezoelectric rod sensors

This study aims to validate a piezoelectric driven-rod scour monitoring system that can sense changes in scour depth along the entire rod at its instrumented location. The proposed sensor is a polymeric slender rod with a thin strip of polyvinylidene fluoride that runs through its midline. Extraction of the fundamental frequency allows the direct calculation of the exposed length (or scour depth) of the slender rod undergoing fluid flow excitation. First, laboratory validation in dry conditions is presented. Second, hydrodynamic testing of the sensor system in a soil-bed flume is discussed. Each rod was installed using a three-dimensional-printed footing designed for ease of installation and stabilization during testing. The sensors were installed in a layout designed to capture symmetric scour conditions around a scaled pier. In order to analyze the system out of steady-state conditions, water velocity was increased in stages during testing to induce different degrees of scour. As ambient water flow excited the portion of the exposed rods, the embedded piezoelectric element outputted a time-varying voltage signal. Different methods were then employed to extract the fundamental frequency of each rod, and the results were compared. Further testing was also performed to characterize the relationship between frequency outputs and flow velocity, which were previously thought to be independent. In general, the proposed driven-rod scour monitoring system successfully captured changing frequencies under varied flow conditions

Advances in co-volume mesh generation and mesh optimisation techniques

This paper introduces developments in modified techniques for the generation of unstructured, non-uniform, dual orthogonal meshes which are suitable for use with co-volume solution schemes. Two new mesh generation techniques, a modified advancing front technique and an octree-Delaunay algorithm, are coupled with a mesh optimisation algorithm. When using a Delaunay–Voronoi dual, to construct mutually orthogonal meshes for co-volume schemes, it is essential to minimise the number of Delaunay elements which do not contain their Voronoi vertex. These new techniques provide an improvement over previous approaches, as they produce meshes in which the number of elements that do not contain their Voronoi vertex is reduced. In particular, it is found that the optimisation algorithm, which could be applied to any mesh cosmetics problem, is very effective, regardless of the quality of the initial mesh. This is illustrated by applying the proposed approach to a number of complex industrial aerospace geometries

Le gouvernement de Tony Blair et la crise afghane

Cet article est la traduction d'une allocution prononcée par Lord Morgan à l'occasion d'une conférence sur le New Labour, in, Valérie AUDA-ANDRE (ed.), Les années Blair, Toulon : Observatoire de la Société Britannique & BABEL, 2007, intitulée The Blair Government and the Afghan Terrorist Crisis Traduction de Valérie Auda-André, Jean-Philippe Fons, Gilles Leydier, Jean-Paul Révauger et Timothy WhittonInternational audienceLe 8 juin 2001, le gouvernement de Tony Blair aurait dû être au comble du bonheur ; il venait de remporter les élections pour la deuxième fois consécutive. Pour la première fois de son histoire vieille d'un siècle, le Parti travailliste avait gagné de façon exemplaire le droit d'exercer un deuxième mandat électoral. Sa majorité de 167 sièges était presque aussi écrasante que celle obtenue lors des élections de 1997. Pratiquement toutes les avancées réussies alors avaient été consolidées dans tout le pays. Le Parti conservateur était pratiquement en déroute et malgré tous les efforts déployés pendant la campagne électorale de 2001, il n'avait réussi à emporter qu'un total de 166 sièges, tout juste un de plus qu'en 1997. Le chef du Parti, William Hague, démissionna sur le champ

Intravital Multiphoton Microscopy with Fluorescent Bile Salts in Rats as an In Vivo Biomarker for Hepatobiliary Transport Inhibition

The bile salt export pump (BSEP) is expressed at the canalicular domain of hepatocytes, where it mediates the elimination of monovalent bile salts into the bile. Inhibition of BSEP is considered a susceptibility factor for drug-induced liver injury that often goes undetected during nonclinical testing. Although in vitro assays exist for screening BSEP inhibition, a reliable and specific method for confirming Bsep inhibition in vivo would be a valuable follow up to a BSEP screening strategy, helping to put a translatable context around in vitro inhibition data, incorporating processes such as metabolism, protein binding, and other exposure properties that are lacking in most in vitro BSEP models. Here, we describe studies in which methods of quantitative intravital microscopy were used to identify dose-dependent effects of two known BSEP/Bsep inhibitors, 2-[4-[4-(butylcarbamoyl)-2-[(2,4-dichlorophenyl)sulfonylamino]phenoxy]-3-methoxyphenyl]acetic acid (AMG-009) and bosentan, on hepatocellular transport of the fluorescent bile salts cholylglycyl amidofluorescein and cholyl-lysyl-fluorescein in rats. Results of these studies demonstrate that the intravital microscopy approach is capable of detecting Bsep inhibition at drug doses well below those found to increase serum bile acid levels, and also indicate that basolateral efflux transporters play a significant role in preventing cytosolic accumulation of bile acids under conditions of Bsep inhibition in rats. Studies of this kind can both improve our understanding of exposures needed to inhibit Bsep in vivo and provide unique insights into drug effects in ways that can improve our ability interpret animal studies for the prediction of human drug hepatotoxicity

Investigating the Ecology of the Mound-Building Ant, \u3ci\u3eAcanthomyops Claviger\u3c/i\u3e (Hymenoptera: Formicidae), in Re-Created Prairie

Acanthomyops claviger (Roger) (Hymenoptera: Formicidae) forms conspicuous mounds within clumps of big bluestem, Andropogon gerardii, and prairie dropseed, Sporobolus heterolepsis, within a re-created tallgrass prairie in northeastern Illinois. This study explored the ecology of the nesting ant in the recreated prairie regarding the persistence of colonies, soil characteristics, the growth of grass clumps, and the species richness of the surrounding flora. Persistence of nests over one year was positively correlated to the diameters of mounds created by the colonies. Differences in soil moisture at 10 cm depth were significant over a growing season between grass clumps having nests of A. claviger and those not. Soil temperature at 10 cm depth over a growing season, organic fraction of the soil, and above-ground oven-dried biomass of grasses did not significantly vary based on nest presence. Floral richness was significantly higher in the vicinity of A. claviger nests than where nests were absent. Benefits of the ant-grass relationship are unknown, although a commensalistic relationship is at least suggested by the location of nests in grass clumps. The presence of A. claviger nests appears to have a positive effect on the richness of the surrounding flora, possibly through soil tunneling and seed distribution

Integration of domain and resource-based reasoning for real-time control in dynamic environments

A real-time software controller that successfully integrates domain-based and resource-based control reasoning to perform task execution in a dynamically changing environment is described. The design of the controller is based on the concept of partitioning the process to be controlled into a set of tasks, each of which achieves some process goal. It is assumed that, in general, there are multiple ways (tasks) to achieve a goal. The controller dynamically determines current goals and their current criticality, choosing and scheduling tasks to achieve those goals in the time available. It incorporates rule-based goal reasoning, a TMS-based criticality propagation mechanism, and a real-time scheduler. The controller has been used to build a knowledge-based situation assessment system that formed a major component of a real-time, distributed, cooperative problem solving system built under DARPA contract. It is also being employed in other applications now in progress