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  • 1
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    Cambridge Spitsbergen Expedition, 1972 (1973)
    Cambridge University Press
    Details
    Publication Date: 1973-01-01
    Print ISSN: 0032-2474
    Electronic ISSN: 1475-3057
    Topics: Ethnic Sciences , Geography
    Published by Cambridge University Press
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  • 2
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    Pulsating flow in a curved tube (1973)
    Cambridge University Press
    Details
    Publication Date: 1973-08-07
    Description: An analysis is presented of laminar fully developed flow in a curved tube of circular cross-section under the influence of a pressure gradient oscillating sinusoidally in time. The governing equations are linearized by an expansion valid for small values of the parameter (a/R) [Ka/ων]2, where a is the radius of the tube cross-section, R is the radius of curvature, ν is the kinematic viscosity of the fluid and K and ω are the amplitude and frequency, respectively, of the pressure gradient. A solution involving numerical evaluation of finite Hankel transforms is obtained for arbitrary values of the parameter α = a(ω/ν)½. In addition, closed-form analytic solutions are derived for both small and large values of α. The secondary flow is found to consist of a steady component and a component oscillatory at a frequency 2ω, while the axial velocity perturbation oscillates at ω and 3ω. The small-α flow field is similar to the low Dean number steady flow configuration, whereas the large-α flow field is altered and includes secondary flow directed towards the centre of curvature. © 1973, Cambridge University Press. All rights reserved.
    Print ISSN: 0022-1120
    Electronic ISSN: 1469-7645
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Published by Cambridge University Press
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  • 3
    Electronic Resource
    Electronic Resource
    Stability conditions for the solutions of the hartree-fock equations. VII. Stability of some closed-shell nonalternant systemsQTG Publication M-121. (1973)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 7 (1973), S. 87-108 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The instabilities of the solutions to the Hartree-Fock equations for the nonalternants in the pentalene, heptalene, etc., series and in the azulene, etc., series are examined. The systems are found to have symmetry-adapted solutions which are unstable for values of the core integral β close to the standard (spectroscopic) value; for example, the pentalene solution is unstable with β equal to 75% of its standard value. The “broken” symmetry solutions although exhibiting only a very slightly lower energy (0.01 eV) may exhibit dramatically different values for other properties, e.g., 30% changes in bond orders. The off-diagonal charge-density wave (CDW) appearing in the “broken” symmetry solutions at the onset of instability is amplified as the cooperative phenomena dominate, until in the “fully correlated” limit, the linked-ethylenic (bond alternating) structure is obtained.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560070110
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  • 4
    Electronic Resource
    Electronic Resource
    Membrane ultrafiltration of a nonionic surfactant (1973)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 19 (1973), S. 766-774 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Aqueous solutions 1.65 × 10-4 to 1.10 × 10-2 molar in the nonionic surfactant Triton X-100 are subjected to membrane ultrafiltration over the temperature range of 22 to 50°C in a continuous flow, thin channel cell, with channel Reynolds numbers from 50 to 1175. Data for the ultrafiltrate flux through the optimum polyelectrolyte complex membrane (of the three tested) are correlated by an equation involving the in-series resistances of the membrane and of the polarized boundary layer of the sufactant rejected by the membrane, with the latter resistance varied over a wide range. The correlations are used to estimate the required membrane area and resultant ultrafiltrate concentration of surfactant to achieve any specified water recovery using cells-in-series and cells-in-parallel operation. The gelation concentration and surfactant mass transfer coefficient are used to estimate water flux in the gel-polarization region.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690190414
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  • 5
    Electronic Resource
    Electronic Resource
    Electrostatic interactions in polyglutamic acid (1973)
    New York : Wiley-Blackwell
    Biopolymers 12 (1973), S. 845-856 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Conformational energy estimates were made for completely charged polyglutamic acid with different assumptions concerning the placement of side chain charge. Viewed as a helix, the minimum energy structure is somewhat affected by the side-chain charge placement. The average energy of the chain viewed as a random coil is equal to or less than the average energy of the chain viewed as a helix. Unlike the polyacrylate chain, nearest-neighbor charge interaction is shown to increase the chain dimensions. Although the calculations are approximate there is little evidence to suggest that isolated polyglutamate molecules in the absence of added electrolyte should behave as rods or that there are significant amounts of locally ordered structures. Presently no experimental results exist under conditions appropriate to isolated molecular calculations.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1973.360120413
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  • 6
    Electronic Resource
    Electronic Resource
    Effect of residual side chain blocking groups and side chain charge on polypeptide conformation in aqueous solution (1973)
    New York : Wiley-Blackwell
    Biopolymers 12 (1973), S. 835-843 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The circular dichroism (CD) spectrum of poly-L-lysine and poly-L-glutamic acid has been investigated in the presence of a small percent of side-chain blocking groups. The blocking groups benzyl, methyl, and carbobenzoxy show qualitatively similar effects. Less than five mole percent of aromatic blocking groups alters the CD spectrum. Consequently, unsuspected blocking groups may account for the variation observed in CD spectra of these polymers. A weak CD band at 235-240 nm was observed for the disordered unblocked polymer even in the absence of electrolyte. Viscosity data indicate that in salt-free solutions these chains at neutral pH still behave as random coils though with reduced conformational freedom, in contrast to some polyelectrolytes which behave as rigid rods in the absence of electrolyte. The viscosity data bring into question the relevance of isolated molecule conformational calculations to experimental CD spectra.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1973.360120412
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  • 7
    Electronic Resource
    Electronic Resource
    Synthese von Haschisch-Inhaltsstoffen. 6. Mitteilung5. Mitt. s. [1]. (1973)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 56 (1973), S. 519-524 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of a new (-)-Δ8-6a,10a-trans-tetrahydrocannabinol analogue, containing a N-methyl-3-propyl-pyrrolidin-3-yl side-chain, is reported.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19730560149
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  • 8
    Electronic Resource
    Electronic Resource
    Synthese von Haschisch-Inhaltsstoffen. 5. Mitteilung4. Mitt. s. [1]. (1973)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 56 (1973), S. 510-518 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A (-)-Δ8-6a,10a-trans-tetrahydrocannabinol analogue, with a methyl-(3-dimethyl-amino-propyl)-amino side-chain instead of the n-pentyl radical in the naturally occurring product, has been synthesized by condensing 5-methylamino-resorcinol tosylate with (+)-trans-p-2,8-menthadien-1-ol.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19730560148
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  • 9
    Electronic Resource
    Electronic Resource
    Poly α-ester degradation studies. IV. Rheological studies of polymer degradation (1973)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 11 (1973), S. 2031-2043 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Farol-Weissenberg rheogoniometer has been used to follow molecular weight changes during the degradation of certain poly-α-esters in the melt state. By observing the change in melt viscosity at low shear rates it had been shown that the decomposition of the poly(isopropylidene carboxylate) is substantially first-order with respect to the molecular weight of the residual polymer. The derived kinetic parameters are in good agreement with those previously obtained by other techniques. This provides a substantial piece of supporting evidence for the view that degradation takes place predominantly by intramolecular ester interchange involving the formation of 1,1,4,4,-tetramethylglycollide. The introduction of β-chlorine atoms into the polymer structure leads to a more complex degradation pattern. Thus the presence of a single β chlorine atom per repeat unit, as in poly(3-chloro-2-methyl-2-hydroxypropionic acid) leads to a substantially similar dependence on molecular weight with the added complication of progressive crosslinking which becomes more apparent in later stages of the reaction. This crosslinking reaction plays an increasingly important part as the extent of chlorination of the polymer is increased. In addition, the presence of chlorine leads to an increased sensitivity of the degradation reaction to the presence of oxygen.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1973.170110822
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  • 10
    Electronic Resource
    Electronic Resource
    Analysis of the kinetics of the thermal and chemically activated elimination of HF from 1,1,1-trifluoroethane: the C—C bond dissociation energy and the heat of formation of 1,1,1-trifluoroethane (1973)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 5 (1973), S. 965-975 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The thermal, unimolecular elimination of HF from CH3CF3 was studied by three different groups over the temperature range 1000° to 1800°K. While the reported kinetic parameters varied greatly, it is shown here that these data may be satisfactorily correlated in terms of a four-center transition state. This correlation results in ΔE00 ++ = 69.2 kcal/mol, and log (k/s-1) = 14.6 - 72.6/θ. These results may then be combined with the kinetics of the chemically activated elimination of HF from CH3CF3 formed by the recombination of methyl and trifluoromethyl radicals. The data from three different laboratories are shown to be in excellent agreement. These data, combined with extant thermal data, yield as a best value DH00(CH3—CF3) = 99.6 ± 1.1 kcal/mol. This gives the unexpectedly high value of DH298°(CH3—CF3) = 101.2 ± 1.1 kcal/mol. It is suggested that dipoledipole interactions, primarily in CH3CF3, account for this surprisingly strong C—C bond dissociation energy. These results also yield δHf0(CH3CF3; g, 298) = -178.6 ± 1.5 kcal/mol.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550050606
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