Correction to Kornblum et al.

Reports an error in "Dimensional overlap: Cognitive basis for stimulus-response compatibility--A model and taxonomy" by Sylvan Kornblum, Thierry Hasbroucq and Allen Osman (Psychological Review, 1990[Apr], Vol 97[2], 253-270). In this article, erroneous data were included in Figure 2. The figure and original caption are corrected in the erratum. (The following abstract of the original article appeared in record 1990-18942-001.) The classic problem of stimulus–response (S-R) compatibility (SRC) is addressed. A cognitive model is proposed that views the stimulus and response sets in S-R ensembles as categories with dimensions that may or may not overlap. If they do overlap, the task may be compatible or incompatible, depending on the assigned S-R mapping. If they do not overlap, the task is noncompatible regardless of the assigned mapping. The overlapping dimensions may be relevant or not. The model provides a systematic account of SRC effects, a taxonomy of simple performance tasks that were hitherto thought to be unrelated, and suggestive parallels between these tasks and the experimental paradigms that have traditionally been used to study attentional, controlled, and automatic processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Chaos hamiltonien

Hamiltonian chaos is illustrated through the chaotic regime of a synchronous dipolar motor. This regime is explained with a quite simple Hamiltonian which describes the nonlinear pendulum in a particular limiting case. Phase space structure as revealed by a stroboscope relies upon the nesting of resonances and the tangle of stable and unstable manifolds.     

Well-balanced schemes versus fractional step method for hyperbolic systems with source terms

Abstract The paper is devoted to the analysis of the true accuracy of different schemes when computing a simple hyperbolic model with source terms, which describes the motion of two-phase flows including source terms. The strategy of upwinding the source terms is investigated and compared with the standard fractional step method. A first scheme relies on the usual fractional step approach. A second scheme applies for upwinding of source terms. It, however, does not provide satisfactory results when computing certain specific unsteady cases. This behaviour can be easily explained. It thus motivates us to introduce a third scheme, which is similar to the previous but aims at providing an increased accuracy on coarse meshes when computing highly unsteady flows. This latter scheme requires us to define a cell scheme which computes the void fraction with the help of a modified governing equation, while using the same interface solver. A detailed numerical study which includes a measure of the L ¹ norm of the error completes the work.     

Geometric constraint solving: The witness configuration method

Geometric constraint solving is a key issue in CAD, CAM and PLM. The systems of geometric constraints are today studied and decomposed with graph-based methods, before their numerical resolution. However, graph-based methods can detect only the simplest (called structural) dependences between constraints; they cannot detect subtle dependences due to theorems. To overcome these limitations, this paper proposes a new method: the system is studied (with linear algebra tools) at a witness configuration, which is intuitively similar to the unknown one, and easy to compute.     

The use of atomic hydrogen for low temperature oxide removal from HgCdTe

Reflection high energy electron diffraction (RHEED) patterns of HgCdTe surfaces etched with bromine methanol are diffuse with a faint ring pattern indicative of an overlayer consisting of a mixture of oxides and amorphous Te. Exposure to an atomic hydrogen flux results in a RHEED pattern indicative of a high quality, two-dimensional surface. Atomic force microscopy (AFM) measurements indicate a rms surface roughness less than 1 nm. CdTe grown on this surface at 80°C maintains the streaky RHEED pattern and smooth surface as indicated by AFM. X-ray photoelectron spectroscopy measurements indicate that the etched surfaces contain both an oxide layer and a metallic Te overlayer which were removed by continued exposure to atomic hydrogen. Further exposure results in significant HgTe depletion, which appears to be a near-surface phenomenon. Preliminary device results indicate that use of atomic hydrogen is a viable approach for low temperature cleaning of etched HgCdTe surfaces.     

Effet différentiel du vieillissement sur les processus impliqués dans la génération d'images mentales.

The purpose of this study was to measure the degree to which the deterioration of mental image generation processes observed in elderly subjects by Dror and Kosslyn (1994) depends on the nature of the processing (referential vs. representational) involved in performing the task at hand. In keeping with the results of research showing that processing resources diminish as normal aging occurs (Craik & Bird, 1982; Rabinowitz, Craik & Ackerman, 1982), we suggest that generation ability based on referential processing is affected to a greater extent in older adults than is the generation ability involving representational processing. Fifteen young adults and 15 elderly persons performed a generation task modeled on that used by Dror and Kosslyn (1994). Observations were based on two contrasting conditions. In the first instance, subjects were required to generate an image representation of numbers when instructed to do so by a graphic stimulus, e.g., "31" (representational generation). In the second case, generation was produced on the basis of a verbal stimulus, e.g., "thirteen" (referential generation)... (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Impact of Water Temperature on Resolving the Challenge of Assuring Disinfection While Limiting Bromate Formation

Intensive pilot studies were performed to study the impact of ozone dose (0.6 to 3.5 mg/L), pH (6.0 to 7.5), and contact time (12 to 38 min) on bromate (BrO₃) formation, for different sand-filtered water qualities from the Neuilly-sur-Marne Treatment Plant (COT = 1.3 to 2.2 mg/L, TAC = 190 to 230 mg CaCO₃, [Br^?] = 25 to 50 μg/L, and T = 5°C to 26°C). Whatever the water quality studied, the main factors influencing bromate formation were ozone dose, pH, and a cross factor between them. Bromate formation was shown to be proportional to bromide concentration, and to increase only slightly with temperature, depending on the ozone dose and the pH. As on the contrary temperature has an important impact on disinfection, especially when considering Cryptosporidium inactivation, resolving the challenge of ensuring disinfection while limiting bromate formation was shown to be quite easily achievable, at intermediate temperature, and with more stringent conditions at high temperature (because of bromate formation) or at low temperature (because of disinfection).     

Heterogeneous anionic ring opening polymerization in a fixed‐bed reactor: description of the process and modelling

Grafting active centres on a solid porous support and using alcohol molecules as a transfer agent permitted coordinated anionic ring opening polymerization of oxygenated heterocycles by a continuous process. Dehydrated porous silica or alumina have been employed as solid supports. After grafting aluminium alkoxides on these supports, ε‐caprolactone and dimethyltrimethylene carbonate have been polymerized. Conversion as well as molecular weights were dependent on the contact time of reactants within the porous phase. A model of this continuous process has been developed by a combination of a Monte Carlo simulation with a reactor model based on the contact time distribution concept. Copyright © 2004 Society of Chemical Industry