Selective attention and the acquisition of new phonetic categories.

A class of selective attention models often applied to speech perception is used to study effects of training on the perception of an unfamiliar phonetic contrast. Attention-to-dimension (A2D) models of perceptual learning assume that the dimensions that structure listeners' perceptual space are constant and that learning involves only the reweighting of existing dimensions to emphasize or de-emphasize different sensory dimensions. Multidimensional scaling is used to identify the acoustic-phonetic dimensions listeners use before and after training to recognize the 3 classes of Korean stop consonants. Results suggest that A2D models can account for some observed restructuring of listeners' perceptual space, but listeners also show evidence of directing attention to a previously unattended dimension of phonetic contrast. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Accurate environmental bioindication in floodplains in spite of an extreme flood event

The ecological reaction of species on environmental factors can differ both, temporally and geographically. Therefore, bioindicator systems must be shown to remain accurate at different places and points of time. Extreme events pose challenges for testing this robustness, which has not yet been explored systematically. The unique opportunity of the extreme flooding of the river Elbe in August 2002 was used for such a test. The bioindicator system for mean groundwater depth during the vegetation period and annual duration of inundation in floodplains studied here was developed with data collected in 1999. Data from 2003 were used to analyse the dependence of the bioindication results on the humidity of the study plots and taxonomic group (plants, molluscs and carabid beetles). For the duration of inundation, the accuracy of bioindication in 2003 was similar to that in 1999, except for the medium‐humid and dry plots using molluscs as indicators. For groundwater depth, the accuracy of bioindication in 2003 was similar to that of the reference year except in the dry plots with significantly lower accuracy for all species groups. With a few exceptions, the bioindicator system is shown to be robust and to remain accurate in spite of an extreme flood event. In conclusion, the relevance of extreme events for the robustness of bioindicator systems differs between the indicated parameters and taxonomic groups. The results stress the need to take into account the limits of the working range and the occurrence of extreme events, when testing and applying bioindicator systems. Copyright © 2009 John Wiley & Sons, Ltd.     

Silicon Carbide-Coated Boron Fibers

A study of a silicon carbide-coated boron fiber showed that it retained its room-temperature strength after being heated to 1000°C for 24 h in air. This fiber was consolidated successfully in a titanium matrix at 930°C without degradation, although previous results with another silicon carbide-coated boron fiber indicated that there might be a reaction problem at this temperature.     

Palm kernel shell as fuel for burning bricks

The use of an agricultural waste product, palm kernel shell, as a fuel for firing bricks is explored as a means of reducing environmental degradation and depletion of scarce firewood in Ghana. A simple but efficient methodology of clamp firing bricks using the new fuel is developed and tested. The resulting bricks are analysed for physical properties and suitability for construction use. The viability of palm kernel shell as a fuel for small-scale brick industries is considered. On etudie actuellement au Ghana les possibilites d'utilisation d'un dechet agricole, en l'occurrence, les coquilles de noix de palme, comme combustible dans les briqueteries; une telle solution permettrait de reduire la degradation de l'environnement et de diminuer l'appauvrissement des maigres reserves en bois de chauffage du pays. A cet effet, on met au point une methodologie simple mais efficace de cuisson des briques en brulant des dechets de coquilles de noix de palme. On analyse les proprietes physiques de ces briques et on verifie qu'elles conviennent a la construction. On etudie la viabilite de la coquille de noix de palme pour l'alimentation en combustible des petites briqueteries.     

Extreme Thermal Loading on Steel Bridges in Tropical Region

In the design of highway bridges, it is important to consider the thermal stresses induced by the nonlinear temperature distribution in the bridge deck irrespective of their spans. To cope with this, design temperature profiles are provided by many bridge design codes, which are normally based on extensive research on the thermal behavior of bridges. This paper presents the results of a comprehensive investigation on the thermal behavior of steel bridges carried out in Hong Kong. A method for predicting bridge temperatures from given meteorological conditions is briefly discussed. The theoretical results have been validated by temperature measurements on experimental models mounted on the roof of a building as well as on an existing steel bridge. Both the theoretical and field results confirm the validity of the one-dimensional heat transfer model on which most design codes are based. Values of design thermal loading for a 50-year return period are determined from the statistics of extremes over 40 years of meteorological information in Hong Kong. The design temperature profiles for various types of steel bridge deck with different thickness of bituminous surfacing are developed.     

Modelling sweetness and texture perception in model emulsion systems

Model emulsion samples, prepared subject to a d-optimal response surface design, were used to investigate the effect of rapeseed oil, sugar and hydroxypropyl methyl cellulose thickener (HPMC) on perceived sweetness, textural attributes (thickness, stickiness, mouth-coating, dispersing), instrumental measures of apparent viscosity 50 s⁻¹ and Kokini oral shear stress. An increase in oil, sugar and HPMC resulted in an increase in perceived thickness, stickiness and mouth-coating, and a decrease in dispersion; sweetness was enhanced by the addition of both sugar and oil but suppressed by the addition of HPMC. Viscosity and Kokini oral shear stress were well correlated with oral thickness (r ² > 0.9). Validated multiple linear regression models highlighted several 2-factor interactions between ingredients. Model statistics indicated that the variation in data was well explained; the models were predictive and could be used to navigate the design space. Samples predicted to be iso-thick and iso-sweet could not be discriminated (P > 0.10) in a 3-alternative forced choice (3-AFC) test using 35 panellists.     

Microsystems elements based on free-standing thick-films made with a new sacrificial layer process

A new process derived from screen-printing technology and based on thick sacrificial layers has been developed in our laboratory for the fabrication of films partially released from the substrate. The sacrificial layer acts as a stable mechanical support during the firing of the active layer and is totally removed after the final thermal treatment of the sample. Fabrication of a copper electrothermal actuator was undertaken to demonstrate the efficiency of this simple, collective and low cost process. Passive components based on this new process include the fabrication of heating resistors, strain gauges and microchannels. Moreover, the process can also be used to facilitate the implementation of piezoelectric devices.     

Experimental Evidence for the Existence of the Ti3B4 Phase

Experimental evidence for the formation of Ti₃B₄ with an orthorhombic Ta₃B₄-type structure is presented. This phase forms by a peritectic reaction between TiB₂ and liquid at ∼2200°C and is stable to temperatures at least as low as 1690°C, the lowest temperature at which samples were annealed. No evidence was found to indicate the presence of a second high-temperature form of this phase, as has been reported in the literature.