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  • Polymer and Materials Science  (2)
  • Hybrid mobile phases containing alcohols  (1)
  • Maximal oxygen consumption  (1)
  • 1
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Hybrid mobile phases containing alcohols ; Solute-micelle association constants ; Polynuclear aromatic hydrocarbons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The interaction between some polynuclear aromatic hydrocarbons of environmental concern, and sodium dodecylsulphate and hexadecyltrimethylammonium bromide in the presence of methanol, 2-propanol and n-butanol has been evaluated by high-performance liquid chromatography using micellar mobile phases. Solute-micelle association constants have been determined for the compounds investigated. The results show that the addition of the alcohol to the mobile phase decreases the association constant values, methanol 〈2-propanol 〈n-butanol, relative to those in the absence of any additive.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    European journal of applied physiology 76 (1997), S. 561-565 
    ISSN: 1439-6327
    Keywords: Key words Laddermill exercise ; Maximal oxygen consumption ; Treadmill exercise ; Work capacity ; Heart rate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Maximal O2 consumption (V˙O2max) is an index of the capacity for work over an 8 h workshift. Running on a treadmill is the most common method of eliciting it, because it is an easy, natural exercise, and also, by engaging large muscle masses, larger values are obtained than by other exercises. It has been claimed, however, that climbing a laddermill elicits a still higher V˙O2max, probably because more muscle mass is apparently engaged (legs + arms) than on the treadmill (legs only). However, no data in support of this claim have been presented. To see if differences exist, we conducted progressive tests to exhaustion on 44 active coal miners, on a laddermill (slant angle 75°, vertical separation of rungs 25 cm) and on a treadmill set at a 5% gradient. The subjects' mean (range) age was 37.4 (31–47) years, height 174.3 (164–187) cm, body mass 82.2 (64–103) kg. Mean (range) V˙O2max on the laddermill was 2.83 (2.31–3.64) l · min−1 and 2.98 (2.03–4.22) l · min−1 on the treadmill (P 〈 0.01, Student's paired t-test). Mean (range) of maximal heart rate f cmax (beats · min−1) on the laddermill and on the treadmill were 181.0 (161–194) and 181.3 (162–195), respectively (NS). Laddermill:treadmill V˙O2max was negatively related to both treadmill V˙O2max · kg body mass−1 (r = −0.410, P 〈 0.01) and body mass (r = −0.409, P〈 0.01). Laddermill:treadmill f cmax was negatively related to treadmill V˙O2max · kg body mass−1 (r = −0.367, P 〈 0.02) but not to body mass (r = −0.166, P = 0.28). Our data would suggest that for fitter subjects (V˙O2max 〉 2.6 l · min or V˙O2max · kg body mass−1 〉 30 ml · min−1 · kg−1) and/or higher body masses (〉70 kg), exercise on the laddermill is not dynamic enough to elicit a V˙O2max as high as on the treadmill. For such subjects, treadmill V˙O2max would overestimate exercise capacity for jobs requiring a fair amount of climbing ladders or ladder-like structures.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 24 (1986), S. 1943-1959 
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The crystallization kinetics and resultant morphologies of thin films of cis-polyisoprenes from guayule rubber have been studied using osmium tetroxide staining and transmission electron microscopy. Polymers used were extracted from the plant either on a laboratory scale or in a pilot plant operation. The polymers show significantly different behavior with regard to both morphological features and to lamellar growth rates. Freshly extracted cis-polyisoprene as well as freshly prepared specimens of pilot plant rubber show only α growth, as in cis-polyisoprene from hevea, but a slightly faster lamellar growth rate. Aged pilot plant rubber shows both α and β growth, both at higher rates than in natsyn, with the rate of α growth being lower than in hevea. Freshly extracted and aged specimens show a maximum lamellar growth rate at -20°C, whereas the maximum for pilot plant rubber occurs at -24°C. The data are interpreted in terms of oxidation of double bonds during aging to produce pendant ester groups. Lamellar growth rates and infrared analyses are both consistent with 1.2-1.5% of the double bonds being affected. Data from guayule and natsyn are now consistent in showing that the effects of microstructural impurities on the crystallization of cis-polyisoprene are to reduce the rates of α-lamellar growth and to induce the β growth, which would not otherwise exist. Secondary nucleation analyses show the regime II-III transition, as in hevea; however, the temperature of the transition, as well as the ratio of the slopes, is different for this linear polymer.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 24 (1979), S. 1777-1785 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The activation energy (Ea) for the dehydrochlorination of PVC and PVC stabilized with an epoxide was determined by a method involving dynamic pH measurements. The Ea increase was 5 kcal/mole between unformulated PVC (Ea = 22.6 kcal/mole) and any of the other formulations (Ea = 27.7-28.6 kcal/mole). On the basis of this and data contained in the literature, research alternatives for the stabilization mechanism are proposed using model compounds.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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