A comparison between the enhanced mass transfer in boundary and pressure driven oscillatory flow

Mass transport in pulsating flow devices using either moving boundaries or oscillating imposed pressure drops are compared with each other by means of a calculation using a simple model. We conclude that there is no difference between the two configurations as long as one is interested only in the power required to move the fluid for the convective mass transport achieved. However, the boundary driven configuration is more efficient if the power is divided by the total mass transport where both the diffusive and convective parts are taken into account, the boundary driven configuration is more efficient. The amplitude of the piston stroke in the pressure driven configuration and the amplitude in the boundary driven case are assumed to be the same, and the inertia of the moving devices themselves are ignored in this calculation.     

The effects of widowhood on physical and mental health, health behaviors, and health outcomes: The Women's Health Initiative.

This study examined whether widowhood was associated with physical and mental health, health behaviors, and health outcomes using a cross-sectional (N=72,247) and prospective (N=55,724) design in women aged 50-79 years participating in the Women's Health Initiative observational study (85.4% White). At baseline, married women reported better physical and mental health and generally better health behaviors than widowed women. Whereas women who remained married over the 3-year period showed stability in mental health, recent widows experienced marked impairments and longer term widows showed stability or slight improvements. Both groups of widows reported more unintentional weight loss over the 3-year period. Changes in physical health and health behaviors were inconsistent, with generally small effect sizes. Findings underscore the resilience of older women and their capacity to reestablish connections, but point to the need for services that strengthen social support among women who have difficulty during this transition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Absence makes the adaptations grow fonder: Proportion of time apart from partner, male sexual psychology, and sperm competition in humans (Homo sapiens).

Sperm competition occurs when the sperm of multiple males concurrently occupy the reproductive tract of a female and compete to fertilize an egg. We used a questionnaire to investigate psychological responses to the risk of sperm competition for 237 men in committed, sexual relationships. As predicted, a man who spends a greater (relative to a man who spends a lesser) proportion of time apart from his partner since the couple's last copulation reported (a) greater sexual interest in his partner, (b) greater distress in response to his partner's sexual rejection, and (c) greater sexual persistence in response to his partner's sexual rejection. All effects were independent of total time since the couple's last copulation and the man's relationship satisfaction. Discussion addresses limitations of the current research and situates the current results within the broader comparative literature on adaptation to sperm competition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Investigation of amorphous Ni0.60Nb0.40 diffusion barriers

Interactions of Ni_0.60Nb_0.40 amorphous alloys with polycrystalline overlayers of gold and copper and single-crystal substrates of silicon. GaAs and GaP were observed with Auger depth profiling. The Ni-Nb layer was deposited by r.f. sputtering and was approximately 5000 Å thick. The overlayers were evaporated to a thickness of 1000 Å. The amorphous metal reacted with the gold overlayers and the GaAs and GaP substrates at temperatures well below the nominal crystallization temperature of 650 °C. The Cu/Ni-Nb/Si system, in contrast, was stable at 600 °C for at least 1 h. Samples were also measured that had been contaminated with approximately 5–10 at.% O. Complete separation of the niobium and nickel into distinct layers was seen. For the samples on silicon substrates this separation was accompanied by the formation of a nickel silicide layer.     

New intramolecular effect observed for polyesters: An anomeric effect

A series of polyesters was prepared to evaluate hydrolytic stability as a function of cyclohexyl dibasic acid content. The three cyclohexyl dibasic acids: 1,2; 1,3; and 1,4 were formulated into polyesters with two glycols. The proportion of cis and trans isomers was evaluated via ¹H NMR. The hydrolytic stability of short chain polyesters was evaluated in an acetone/water mixture which solubilized the polyesters to mimic oligoester behavior within a thermosetting polyester coating environment. The rate of hydrolysis was monitored by acid titration and corroborated by GPC. Surprisingly, 1,2-cylohexyl diacid-based polyesters were robust, and 1,3-cyclohexyl diacid-based polyesters were the most susceptible to hydrolysis. Evidently, a 1,2-anchimeric effect for cyclohexyl dibasic acid polyesters was not an important consideration, while the 1,3-cyclohexyl ester interaction was. Consequently, an anomeric effect was proposed. Presented at the 81st Annual Meeting of the Federation of Societies for Coatings Technology, November 12–14, 2003, in Philadelphia, PA.