Wind flow patterns about buildings

A knowledge of building wake characteristics is useful in a variety of applications including dispersion of pollutants downwind of conventional or nuclear power plants, airport runway interference effect, take-off/landing limitations at heliports, pedestrian wind comfort, and wind loads on structures. Recent investigations have advanced both understanding of physical flow processes occurring in the near and far wake regions and theoretical predictive capability for flow and diffusion in the far wake region. These studies have shown, for example, that separation cavities immediately downwind are not enclosed by free streamlines as in two-dimensional separation/reattachment, that organized vortices can play an important role in wake development, and that theoretical solutions for some wake regions are possible.     

Increasing the corrosion resistance of low-alloy and carbon steels for automobile construction by optimizing the metallurgical technology

It is shown that the corrosion resistance of automobile sheet can be improved by ensuring that steels of this type have a low content of corrosion-active nonmetallic inclusions (CANI). The main mechanisms responsible for the formation of CANI in automobile sheet have been established, and recommendations have been developed to reduce their concentration in this product • optimize the deoxidation processes that are used by ensuring that the proportions of the additions made to the steel are consistent with the composition of the ladle slag and that certain key temperature-time parameters of these processes are maintained • control the composition of the ladle slag to prevent the formation of solid phases in the slag and their transfer to the metal; certain conditions must also be observed in the argon blow and the introduction of the addtions. Use of the above recommendations to make automobile sheet and tube steels cleaner with respect to their content of CANI and thus help optimize out-of-furnace treatments at metallurgical and pipe plants will make it possible to improve the corrosion resistance of metal products used in automotive manufacturing. __________ Translated from Metallurg, No. 2, pp. 45–48, February, 2006.     

Interactive anatomy online

The scientific community and general public can best take advantage of the benefits of 3D digital reconstructions if they are stored in a Web-accessible, easy-to-access database. We describe MorphologyNet/sup /spl copy// a Web-based digital library of realistic, 3D interactive and customizable images of anatomy currently in development at the University of Missouri-Rolla.     

A tool to evaluate the fertiliser value and the environmental impact of substrates from wastewater treatment.

Fertilisers may contain pollutants that are applied to the field together with the nutrients. Comparing fertilisers is difficult because of their different concentrations of nutrients and pollutants. In this study an already existing model was taken. It was further developed to compare nutrient fluxes (N, P, K, Ca, Mg, S, humus) and pollutants (heavy metals and pharmaceuticals) of pig and cattle slurry as well as human urine. The data used is taken from literature and, in the case of pharmaceuticals in urine, daily excretion rates were calculated. An amount of 19 m3 ha(-1) a(-1) undiluted urine can be applied, limiting factor is sulphur. Without taking over-fertilisation into account, an addition of mineral fertiliser is required to any organic fertiliser application. In general, heavy metal, antibiotic, and hormone fluxes are higher by using animal manure then urine as fertiliser. However, additional loads of other pharmaceuticals consumed by humans have to be considered. Overall, the model is a suitable tool worthwhile to be extended in aspects of hygiene, environmental impacts as for example, degradation processes as well as ecotoxicology.     

Use of flavour profile and consumer panels to determine differences between local water supplies and desalinated seawater.

The San Diego County Water Authority of California has initiated planning for coastal desalination facilities to augment their water supplies. Integration of the different water qualities from these facilities into existing pipelines must be achieved. This investigation determined whether, and to what degree, consumers can discriminate between desalinated seawater and imported water supplies and how these investigations can contribute to decision making regarding the need for construction of facilities to blend such supplies prior to delivery. Based upon the results of the flavour profile analysis panel and the consumer evaluation sessions, it was concluded that free chlorine versus chloramine disinfection or different concentrations of disinfectants did not significantly affect consumer perception of the taste and odour of desalinated seawater or blends with Colorado River water and State project water. Consumers were able to discern between desalinated seawater and imported water, preferring imported water when forced to make a choice. However, the investigators did not believe that the difference in consumer perception was significant enough to warrant special blending facilities to mitigate the relatively minor aesthetic quality differences between imported water supplies and desalinated seawater.     

Developments in high-resolution positron emission tomography at MGH

The development of high resolution PET systems is important for the wider application of this techniques. The resolution of PET is limited by a number of physical factors such as positron range, small angle deviation, and sampling frequency. The design of the detector array and its sensitivity remain critical factors; designs incorporating analog coding have proven to be useful. PCR-I, a single plane PET system, has demonstrated the concept and has produced useful images in animal studies. PCR-II will extend the concept to a two dimensional detector array resulting in a system with high resolution and high sensitivity.     

Mixed-mode fracture of composites using Iosipescu shear test

Finite element analysis is used to determine the influence of elastic properties on the stress distribution in the Iosipescu shear test specimen. Two different boundary conditions are used which assume either the application of force couples or specified displacements. The effect of orthotropy ratio is investigated with E ₁₁/E ₂₂ranging from 1 to 14.2. The analysis is extended to partially cracked specimens and used to calculate the basic fracture parameters in aligned composite materials. In particular, the failure of specimens with two axial splits, nucleated at the roots of the notches, and extended in the fibre direction is analysed. It is shown that the stress distribution is strongly dependent on both the elastic properties and boundary conditions. The mixed mode stress intensity factors K _Iand K _IIat the crack tips tend to increase with orthotropy ratio. The analysis is discussed with respect to the limited experimental data available for this test geometry. From the numerical and experimental results the mixed mode toughness is estimated in terms of the critical stress intensity factors and the critical energy release rate.Résumé On recourt à une analyse par éléments finis pour déterminer l'influence des propriétés élastiques du matériau sur la distribution des contraintes dans l'éprouvette de l'essai de cisaillement de Iosipescu. Deux conditions aux limites sont considérées: l'application de couples de forces ou de déplacements imposés. L'effet du rapport d'orthotropie est étudié, pour des valeurs de E ₁₁/E ₂₂comprises entre 1 et 14,2. L'analyse est étendue au cas d'éprouvettes partiellement fissurées, et est utilisée pour le calcul des paramètres fondamentaux de rupture dans des matériaux composites à fibres alignées. On analyse en particulier la rupture d'éprouvette comportant deux séparations axiales, prenant naissance aux racines ds entailles et s'étendant dans la direction de la fibrosité.On montre que la distribution des containtes dépend fortement des propriétés élastiques du matériaux et des conditions aux limites. Les facteurs d'intensité de contrainte correspondant au mode mixte K _Iet K _IIde rupture aux extrémités de la fissure tendant à croître avec le rapport d'orthotropie.Une discussion sur cette analyse tient compte du nombre limité de données expérimentales disponibles pour cette géométrie d'éprouvettes. On peut estimer la ténacité sous mode mixte à partir des résultats numériques et expérimentaux, et l'exprimer par les facteurs critiques d'intensité de contraintes et la vitesse critique de relaxation de l'énergie.