Forty-Five Years After Broadbent (1958): Still No Identification Without Attention.

According to D. E. Broadbent's (1958) selective filter theory, people do not process unattended stimuli beyond the analysis of basic physical properties. This theory was later rejected on the basis of numerous findings that people identify irrelevant (and supposedly unattended) stimuli. A careful review of this evidence, however, reveals strong reasons to doubt that these irrelevant stimuli were in fact unattended. This review exposed a clear need for new experiments with tight control over the locus of attention. The authors present 5 such experiments using a priming paradigm. When steps were taken to ensure that irrelevant stimuli were not attended, these stimuli produced no priming effects. Hence, the authors found no evidence that unattended stimuli can be identified. The results support a modern version of Broadbent's selective theory, updated to reflect recent research advances. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Enhanced ground support: lessons from work on reduced crew operations

Cognition, Technology & Work - From the 1950s through the 1980s, aircraft design was marked by an increase in reliability and automation, and, correspondingly, a decrease in the crew complement...     

Iron-Exchanged Zeolite as Effective Catalysts for Friedel–Crafts Alkylation with Alkyl Halides

Friedel–Crafts alkylation of benzene and ethylbenzene with butyl halides has been investigated in the presence of iron-exchanged zeolites. The catalysts showed high conversions and selectivity for monoalkylated products with tertiary and secondary halides under mild reaction conditions (45–60°C). Alkylation of ethylbenzene with 2-chlorobutane can be achieved in 99% yield and 100% selectivity to the monoalkylated product.     

Correlating chemical structure and physical properties of vegetable oil esters

The influence of FA ester chemical structures on the rheology and crystallization temperature of those compounds was evaluated using methyl, n-butyl, n-octyl, and 2-ethyl-1-hexyl FA esters with different chain lengths and different degrees of unsaturation. The rheological properties were analyzed in a high-precision rheometer at various temperatures, and the crystallization temperatures were determined by DSC. Esters produced from the esterification of pure FA and from the transesterification of vegetable oils (i.e., soybean, corn, linseed, and babassu coconut oils) were evaluated. The length of the FA chain was shown to have a marked influence on the viscosity and crystallization temperature of the systems, whereas branching affected only the crystallization temperature to a significant extent. The viscosity and crystallization temperature of the systems were also influenced by the degree of unsaturation. One double bond was shown to increase viscosity, whereas two or three double bonds caused a decrease in the viscosity of the systems. Unsaturation lowered the crystallization temperature in all cases, regardless of the number of double bonds. From all the oils studied, methyl esters from babassu coconut oil presented the lowest crystallization temperatures.     

Nonkinetic changes in heat-treated glasslike carbons part I: Pore size and bulk dimensions

Small-angle X-ray scattering measurements have been used to characterize the radius of gyration R_g of the pores in a glasslike carbon heat treated between 1000 and 2800°C for periods up to 150 hours. Measurements were also made of the irreversible bulk dimensional changes Δl. In both cases, a nonkinetic increase occurs when the heat treatment temperature is increased stepwise to a higher value. The relative changes ΔR_g/R_g and Δl/l exhibit a similar three-region behavior: an initial increase with the annealing temperature up to 1600°C, a plateau up to about 2200°C, and thereafter an increase again. However, the maximum dilatation Δl/l is scarcely 3% whereas the increase in ΔR_g/R_g is twofold. The first region is attributed to a gas pressure mechanism, and the highest-temperature region results from strain relief due to the mismatch of the thermal expansion coefficients in the directions perpendicular and parallel to the layers in graphitic materials. The intermediate region is explained by a combination of both mechanisms.     

Polarization process in FeF3 thin films

A.c. and thermally stimulated depolarization measurements are used to study the polarization mechanisms in FeF₃ thin films. A normalized curve is proposed which shows that the parallel conductance behaviour is governed by a distribution of relaxation times τ equal to τ₀ exp $\text{(}\text{E}\text{kT}\text{)}$. The d.c. model permits the polarization process to be discussed on the basis of successive transfers of electrons from site-to- sites along paths which become shorter and shorter as the frequency increases.     

Metal-catalyzed cross-coupling reactions with supported nanoparticles: Recent developments and future directions

The metal-catalyzed processes are ubiquitous in the modern organic synthesis toolbox. However, a continuous challenge has been related to the design of reactions from a sustainable viewpoint (e.g., easy recovery of the catalyst, ability to perform sequential steps in high yields, avoidance of high amounts of organic solvents). Supported nanocatalysts have prompted special interest because of the synergy involving eletronic and surface effects which can play key roles towards more sustainable processes. In this article, we comprehensively summarize the latest progress in cross-coupling reactions involving supported metal nanoparticles. A background to mechanisms and industrial application will also be presented.     

Catalytic activity of niobium phosphate in the Friedel–Crafts reaction of anisole with alcohols

The influence of acidity, alkyl chain length of alcohols, synthesis temperature and time on the molecular sieve synthesis by adding alcohols to the system for the SBA-1 synthesis were studied. Upon increasing the concentration of alcohols (C_mH_2m+1OH) in the mixture of tetraethyl orthosilicate (TEOS), cetyltriethylammonium bromide (CTEABr), HCl and H₂O, highly ordered P6₃/mmc and p6mm phases were formed when m = 2 and 3 ≤ m ≤ 6, respectively. The amount of HCl was an important factor for the phase-selection under acidic conditions.     

Influence of glycerides–xanthan gum synergy on their performance as lubricants for water‐based drilling fluids

Water‐based fluids for drilling wells are an environmentally friendly alternative to oil‐based formulations typically used in the oil industry. Aqueous mixtures of nonionic monoglyceride surfactants (C6, C8, C10, C12, and C18 carbon chains) and xanthan gum (XG) were investigated with that purpose, correlating their lubricity and solubility in water, as well as using surface tension and contact angle measurements. The results showed that monoglycerides behave as excellent lubricants in water, with a steady decrease of the friction coefficient as the hydrocarbon chain length increased. Monoglycerides were able to reduce the friction coefficient even further when used in XG suspensions, suggesting that they are probably forming a complex with the polysaccharide that shows a synergy toward their performance as lubricants. Experiments of adsorption onto iron oxide nanoparticles also produced evidence of the interaction between these molecules, which favors their adsorption on the metal surface. These results indicate that interactions occurring in solution between the surfactants and the polysaccharide are crucial in the mechanism of action of these mixtures as lubricants in water‐based drilling fluids. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41085.