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ABSTRACT: We report here the self-assembly of surfactant molecules at the interface of air and the hygroscopic quaternary ammonium salt tetrabutylammonium acetate (TBAAc). Homogeneously dissolved surfactant molecules at 100 degrees C self-assemble upon contacting air due to high moisture adsorption by the organic salt when cooling down. Highly ordered lamellar phases with different lattice spacings have been observed when surfactants with various lengths of alkyl chains were used. C(n)TMAB/TBAAc systems showed all-trans conformation of interior methylene carbons and interdigited bilayers with an average CH2 increment of 0.119 nm, while C(n)NH2/TBAAc systems showed trans/gauche mixed conformations of interior methylene carbons and bilayers with an average CH2 increment of 0.247 nm. C(n)NH2s in C(n)NH2/TBAAc formed bilayers through water-mediated intermolecular hydrogen bonds with a water layer thickness of 0.51-0.61 nm. In C(n)TAB/TBAAc, as the head group of C(n)TAB is bigger, the interdigited bilayer thickness (d-spacing) is smaller, because the bigger head groups accommodate enough space for alkyl tails to come in between them.
Journal of Colloid and Interface Science 05/2005; 284(1):278-81. · 3.07 Impact Factor
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Public health reports 02/1961; 76(1):1-10. · 1.33 Impact Factor
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ABSTRACT: As this note is being written, a proposal to provide health insurance to retired workers under Social Security--the Forand bill--is being vigorously debated. Although health care for such workers involves some special considerations, the arguments of the proponents of this bill and the massive support being marshalled for its passage are symptomatic of general concern over voluntary health insurance. The dilemma threatening the survival of many of these voluntary programs is that costs tend to outstrip their ability to provide the quantity and quality of health care demanded by the groups they serve. In this discussion, the authors attempt to identify the major problems currently at issue in voluntary health insurance and to describe and appraise some administrative innovations that have been made in a few instances to control costs and improve the quality of medical and hospital care. (Author's abstract courtesy EBSCO.)
ILR Review. 02/1960; 13(4).
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ABSTRACT: Focuses on the status of workers' compensation policy in the U.S. Promotion of industrial safety and health; Constitutionality and legitimacy of workers' compensation. (Abstract copyright EBSCO.)
ILR Review. 02/1953; 7(1).
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ABSTRACT: Progress of the industrial safety and occupational health movements in the United States toward their common goal of protecting the physical welfare of workers is discussed in this article. When these activities and workmen's compensation began, about a half century ago, it was anticipated that they would be "complementary and mutually sustaining." Besides presenting historical accounts of the safety and health movements, the authors evaluate the current problems and relationships among safety, health, and compensation activities. This article constitutes part of a broader study by the authors to be published under the title "Workmen's Compensation and Occupational Disability." (Author's abstract courtesy EBSCO.)
ILR Review. 02/1953; 6(4).
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ABSTRACT: Unbleached and bleached soft wood pulps have been used as templates and carbon precursors to produce SiC nanorods. Hydrolyzed tetraethylorthosilicate (TEOS), silicic acid was infiltrated into the pulps followed by a carbothermal reduction to form SiC nanorods at 1400 °C in Ar. Residual carbon formed along with SiC was removed by gasification at 700 °C in air. The SiC materials prepared from unbleached pulp were non-uniform SiC with a thick SiO2 coating, while the SiC nanorods prepared from the bleached pulp were uniform and straight with dimensions of 250 nm in diameter and 5.0 mm long. The formation of uniform camelback structure of SiC in the reaction between silica and bleached pulp is attributed to more silica deposited in the amorphous region of cellulose.
Materials Letters. 61(13):2814-2817.
