On the ageing of an aluminium-lithium-zirconium alloy

Electron microscopy has been used to follow the ageing of an aluminium alloy containing 3.08 wt % lithium and 0.19 wt % zirconium over the temperature range 433 to 553 K. A dispersion of Al₃Zr particles was present before these ageing treatments and is unmodified by them. Two dispersions of Al₃Li () are produced by these ageing treatments, one is formed homogeneously in the matrix while the other nucleates and coarsens on the Al₃Zr/matrix interface. From the data it appears that there is little interaction between the lithium and zirconium in solution and that the precipitation processes occur chemically independently. The coarsening characteristics of both dispersions of have been investigated as has the discontinuous precipitation of .     

Relationship of physical appearance of individual mold-damaged cottonseed to aflatoxin content

Over 700 individual aflatoxin-suspect cottonseed were hand-selected from a heterogenous stockpile of ginned seed. The seed were categorized on the basis of (a) bright greenish-yellow, fluorescence termed cateye, on the linter fibers under ultraviolet light; (b) partially bald seed with part of the linter fibers removed by ginning; (c) a combination of cateye and balding; (d) thin and discolored lint; and (e) bluish, not cateye, fluorescence. Aflatoxin assays on each of the 771 selected seed showed that 142 out of 771 (18%) were contaminated by aflatoxin (B₁+B₂) in the range of 150 ppb—5.75 million ppb. Some 93% of the aflatoxin-contaminated seed was concentrated in categories (a), (b), and (c), with the highest concentration, 61%, in category (b). Eight seed in these three categories contained over 1 million ppb of aflatoxins. The data suggest that removal of cateye and partially bald seed from contaminated lots of cottonseed should be more effective for controlling aflatoxin contamination in cottonseed than removal of cateye seed alone.     

L'électrodissolution d'une poudre de galène en milieu d'acétate d'ammonium et d'acide chlorhydrique

Résumé Un modèle d'électrode à caractère pratique est proposé pour la dissolution anodique du sulfure de plomb. Il s'agit d'une poudre de PbS introduite dans un sac monté sur une électrode de graphite. Une évaluation de ses performances est faite dans des conditions trouvées optimales pour une électrode massive; soit l'acétate d'ammonium et l'acide chlorhydrique contenant de la glycine. Son comportement est étudié en fonction de la température et de la concentration de l'électrolyte. Les techniques potentiocinétiques, potentiostatiques et galvanostatiques ont été utilisées pour cette étude. Les produits de réaction sont analysés par différent méthodes telles que ESCA, diffraction aux rayonsX et l'absorption atomique. L'addition d'acide acétique et des produits organiques ne favorisent pas la dissolution en milieu d'acétate d'ammonium. L'acide chlorhydrique dosé avec la glycine se révèle être un meilleur support électrolytique que l'acétate d'ammonium.

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A practical type of electrode has been tested for the anodic dissolution of lead sulphide. This is a polypropylene bag that handles the powder mounted on a graphite anode. Performance of this electrode has been evaluated in ammonium acetate and in hydrochloric acid with glycine. Potentiokinetic, potentiostatic and galvanostatic methods have been used for this investigation.XPS, X-ray diffraction and atomic absorption have been used to identify and quantify the products of electrolysis. The addition of acetic acid and organic products inhibit the anodic dissolution in ammonium acetate solution. Hydrochloric acid with glycine solution has better performance as electrolyte than ammonium acetate solution.

     

The effect of a changing lean gas composition on the ability of NO2 formation and NO x reduction over supported Pt catalysts

Topics in Catalysis - Three model catalysts (Pt/Al2O3, Pt/TiO2, Pt/V2O5/TiO2) were examined in regard to their NO2 formation ability under a changing lean gas composition. The results show that the...     

Cognitive therapy versus exposure and applied relaxation in social phobia: A randomized controlled trial.

A new cognitive therapy (CT) program was compared with an established behavioral treatment. Sixty-two patients meeting Diagnostic and Statistical Manual of Mental Disorders (4th ed.; American Psychiatric Association, 1994) criteria for social phobia were randomly assigned to CT, exposure plus applied relaxation (EXP = AR), or wait-list (WAIT). CT and EXP = AR were superior to WAIT on all measures. On measures of social phobia, CT led to greater improvement than did EXP = AR. Percentages of patients who no longer met diagnostic criteria for social phobia at posttreatment-wait were as follows: 84% in CT, 42% in EXP = AR, and 0% in WAIT. At the 1-year follow-up, differences in outcome persisted. In addition, patients in EXP = AR were more likely to have sought additional treatment. Therapist effects were small and nonsignificant. CT appears to be superior to EXP = AR in the treatment of social phobia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Loneliness is a unique predictor of age-related differences in systolic blood pressure.

A population-based sample of Caucasians, African Americans, and Latino Americans, 50-68 years of age (M = 57.5), from Cook County, Illinois (N = 229), was tested to examine how loneliness and co-occurring psychosocial factors (depressive symptoms, perceived stress, social support, and hostility) were related to indices of cardiovascular and endocrine functioning. Extending prior research, the authors found that loneliness was associated with elevated systolic blood pressure (SBP) and age-related increases in SBP, net of demographic variables, health behavior variables, and the remaining psychosocial factors. Loneliness was not associated with differences in autonomic or endocrine functioning. Although the results are limited by the cross-sectional methods used, they are consistent with the hypothesis that cardiovascular disease contributes to increased morbidity and mortality among lonely individuals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Meta-Analytic Review of Prospective Memory and Aging.

A meta-analysis of prospective memory (PM) studies revealed that in laboratory settings younger participants outperform older participants on tests of both time- and event-based PM (rs=-.39 and -.34, respectively). Event-based PM tasks that impose higher levels of controlled strategic demand are associated with significantly larger age effects than event-based PM tasks that are supported by relatively more automatic processes (rs=-.40 vs. -.14, respectively). However, contrary to the prevailing view in the literature, retrospective memory as measured by free recall is associated with significantly greater age-related decline (r=-.52) than PM, and older participants perform substantially better than their younger counterparts in naturalistic PM studies (rs=.35 and .52 for event- and time-based PM, respectively). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of processing on adherence of a highly extended ham to its cooking bag

Highly extended cook-in-the-bag hams (65% brine/meat), representative of the products currently manufactured in Canada for mass distribution, were prepared using standard industrial equipment. Adherence between the cooked product and its packaging film was evaluated by measuring the force required to peel an excised band of film from the product surface. Overall, film-product adherence did not change after two weeks of refrigerated storage and was not affected by the extent of tumbling (from 360 to 4500 total turns) or by the cooking cycle (constant temperature of 74 °C, constant temperature of 84 °C, or stepwise temperature increase, until core temperature reaches 69 °C). Adherence was considerably reduced, however, when the extended muscles were finely homogenized prior to stuffing. A more detailed analysis of the results suggested that the occasional lack of proper film-product adherence observed in industry during the manufacture of highly extended hams cannot be due to mere deviations from the regular tumbling or cooking cycles. In addition, results point to the necessity of seeking alternative methods to quantify adherence between meat products and their cooking bags.     

Platinum Oxidation and Sulphur Deactivation in NOx Storage Catalysts

Flow reactor experiments and X-ray photoelectron spectroscopy (XPS) measurements were used to investigate the importance of platinum oxide formation on Pt/BaO/Al₂O₃ NO _x storage catalysts during reactions conditions. The reaction studied was NO(g) + 1/2 O₂(g) NO₂(g). During NO₂ exposure of the catalyst the NO₂ dissociation rate decreased during the reaction. This activity decrease with time was also studied with XPS and it was found to be due to platinum oxide formation. The influence of sulphur exposure conditions on the performance of the NO _x storage catalysts was studied by exposing the samples to lean and/or rich gas mixtures, simulating the conditions in a mixed lean application, containing SO₂. The main results show that all samples are sensitive to sulphur and that the deactivation proceeds faster when SO₂ is present in the feed under rich conditions than under lean or continuous SO₂ exposure. Additionally, the influence of the noble metals present in the catalysts was investigated regarding sulphur sensitivity and it was found that a combination of platinum and rhodium seems to be preferable to retain high performance of the catalyst under SO₂ exposure and subsequent regeneration. Finally, the behaviour of micro-fabricated model NO _x storage catalysts was studied as a function of temperature and gas composition with area-resolved XPS. These model catalysts consisted of a thin film of Pt deposited on one-half of a BaCO₃ pellet. It was found that the combination of SO₂ and O₂ resulted in migration of Pt on the BaCO₃ support up to one mm away from the Pt/BaCO₃ interface.