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  • 1
    Electronic Resource
    Electronic Resource
    Quantifying the effect of rheology on lava-flow margins using fractal geometry (1994)
    Springer
    Bulletin of volcanology 56 (1994), S. 193-206 
    Details
    ISSN: 1432-0819
    Keywords: Key words: Fractals ; lava ; rheology ; remote sensing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract. This study aims at quantifying the effect of rheology on plan-view shapes of lava flows using fractal geometry. Plan-view shapes of lava flows are important because they reflect the processes governing flow emplacement and may provide insight into lava-flow rheology and dynamics. In our earlier investigation (Bruno et al. 1992), we reported that flow margins of basalts are fractal, having a characteristic shape regardless of scale. We also found we could use fractal dimension (D, a parameter which quantifies flow-margin convolution) to distinguish between the two endmember types of basalts: a′a (D: 1.05–1.09) and pahoehoe (D: 1.13–1.23). In this work, we confirm those earlier results for basalts based on a larger database and over a wider range of scale (0.125 m–2.4 km). Additionally, we analyze ten silicic flows (SiO2: 52–74%) over a similar scale range (10 m–4.5 km). We note that silicic flows tend to exhibit scale-dependent, or non-fractal, behavior. We attribute this breakdown of fractal behavior at increased silica contents to the suppression of small-scale features in the flow margin, due to the higher viscosities and yield strengths of silicic flows. These results suggest we can use the fractal properties of flow margins as a remote-sensing tool to distinguish flow types. Our evaluation of the nonlinear aspects of flow dynamics indicates a tendency toward fractal behavior for basaltic lavas whose flow is controlled by internal fluid dynamic processes. For silicic flows, or basaltic flows whose flow is controlled by steep slopes, our evaluation indicates non-fractal behavior, consistent with our observations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004450050028
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  • 2
    Electronic Resource
    Electronic Resource
    Quantifying the effect of rheology on lava-flow margins using fractal geometry (1994)
    Springer
    Bulletin of volcanology 56 (1994), S. 193-206 
    Details
    ISSN: 1432-0819
    Keywords: fractals ; lava ; rheology ; remote sensing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract This study aims at quantifying the effect of rheology on plan-view shapes of lava flows using fractal geometry. Plan-view shapes of lava flows are important because they reflect the processes governing flow emplacement and may provide insight into lava-flow rheology and dynamics. In our earlier investigation (Bruno et al. 1992), we reported that flow margins of basalts are fractal, having a characteristic shape regardless of scale. We also found we could use fractal dimension (D, a parameter which quantifies flow-margin convolution) to distinguish between the two endmember types of basalts: a′ a (D: 1.05–1.09) and pahoehoe (D: 1.13–1.23). In this work, we confirm those earlier results for basalts based on a larger database and over a wider range of scale (0.125 m–2.4 km). Additionally, we analyze ten silicic flows (SiO2: 52–74%) over a similar scale range (10 m–4.5 km). We note that silicic flows tend to exhibit scale-dependent, or non-fractal, behavior. We attribute this breakdown of fractal behavior at increased silica contents to the suppression of small-scale features in the flow margin, due to the higher viscosities and yield strengths of silicic flows. These results suggest we can use the fractal properties of flow margins as a remote-sensing tool to distinguish flow types. Our evaluation of the nonlinear aspects of flow dynamics indicates a tendency toward fractal behavior for basaltic lavas whose flow is controlled by internal fluid dynamic processes. For silicic flows, or basaltic flows whose flow is controlled by steep slopes, our evaluation indicates non-fractal behavior, consistent with our observations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00279604
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  • 3
    Electronic Resource
    Electronic Resource
    Block copolymers of amino acids. I. Synthesis and structure of copolymers of L-alanine or L-phenylalanine with D,L-lysine-d7 or D,L-lysine (1977)
    New York : Wiley-Blackwell
    Biopolymers 16 (1977), S. 2005-2028 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Water-soluble block copolymers of the type (A)m-(B)n-(A)p, where (A)m,p was either poly(D,L-lysine-α,β,β,γ,γ,δ,δ-d7) or poly(D,L-lysine) and (B)n was either poly(L-alanine) or poly(L-phenylalanine), were synthesized for conformational studies by proton magnetic resonance spectroscopy. Analytical determination of the amount of the initiator fragment (n-hexylamine) at the C-terminus of the copolymers was used to obtain the number-average degrees of polymerization, DPn, and thereby, together with the amino acid composition, to establish the covalent structures of the polymers. The values of DPn were found to be much lower than those deduced from sedimentation equilibrium or form viscosity measurements. These deviations, which also are thought to have arisen in similar studies reported in the literature, are attributable to intermolecular aggregation; the relation of such aggregation to covalent structure (and its effect on the polymerization reaction) is discussed in terms of the conditions and mechanism of synthesis of block copolymers of amino acids.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1977.360160914
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  • 4
    Electronic Resource
    Electronic Resource
    Helix-coil stability constants for amino acids in nonaqueous solvents. Studies of random poly(γ-benzyl-L-glutamate-co-L-alanine) and poly(γ-benzyl-L-glutamate-co-L-leucine) in a mixed solvent (1981)
    New York : Wiley-Blackwell
    Biopolymers 20 (1981), S. 1435-1458 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The host-guest technique has been applied to the determination of the helix-coil stability constants of two naturally occurring amino acids, L-alanine and L-leucine, in a nonaqueous solvent system. Random copolymers containing L-alanine and L-leucine, respectively, as guest residues and γ-benzyl-L-glutamate as the host residue were synthesized. The polymers were fractionated and characterized for their amino acid content, molecular weight, and helix-coil transition behavior in a dichloroacetic acid (DCA)-1,2-dichloroethane (DCE) mixture. Two types of helix-coil transitions were carried out on the copolymers: solvent-induced transitions in DCA-DCE mixtures at 25°C and thermally induced transitions in a 82:18 (wt %) DCA-DCE mixture. The thermally induced transitions were analyzed by statistical mechanical methods to determine the Zimm-Bragg parameters, σ and s, of the guest residues. The experimental data indicate that, in the nonaqueous solvent, the L-alanine residue stabilizes the α-helical conformation more than the L-leucine residue does. This is in contrast to their behavior in aqueous solution, where the reverse is true. The implications of this finding for the analysis of helical structures in globular proteins are discussed.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1981.360200707
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  • 5
    Electronic Resource
    Electronic Resource
    Anomalous freezing point depression of swollen gelsPaper presented to American Chemical Society and Chemical Institute of Canada, Divisions of Rubber Chemistry, Montreal, May 1967. (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 223-247 
    Details
    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 anomalous freezing point depression, ΔT, of benzene-swollen vulcanizates has previously been attributed to the limitation of (benzene) crystallite size by the polymer network. This study was initiated to determine the benzene crystallite size in a number of rubber and benzene systems. A special low-temperature specimen holder was designed and constructed in the Cambridge Laboratories for running diffraction patterns at temperatures near -30°C. X-ray line broadening techniques were used to study a series of filled and unfilled vulcanizates of varying crosslink density. The results indicate that crystallite size is not depressed to the degree predicted by freezing-point measurements. Benzene crystallite sizes were similar in all rubber benzene systems, regardless of degree of crosslinking or benzene fraction, although carbon black loading appears to increase crystallite size. This effect may be attributed to lesser depth of penetration of the x-rays due to greater density as carbon black loading increases. Additional studies measuring the ΔT for solutions and similar vulcanizates of NR and SBR over a wide range of rubber concentrations showed that at the same rubber in benzene fraction, crosslinking increases ΔT but the addition of carbon black reduces ΔT. An explanation for the observed phenomena is advanced.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1968.070120201
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  • 6
    Electronic Resource
    Electronic Resource
    Preparation of block copolymers of styrene and methacrylic acid (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 629-636 
    Details
    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: A range of block copolymers of styrene and methacrylic acid has been prepared by the suspension method involving migration of a growing radical across a phase boundary. The way in which copolymer composition varies with change in the amount of the two monomers in the reaction mixture has been studied, and explanations are suggested to account for these variations. Two methods, involving calculation from solubility data and thermogravimetric analysis respectively, have been used to give an estimate of the length and composition of the blocks.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070130406
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  • 7
    Electronic Resource
    Electronic Resource
    Compressed fluid technology: Application to RIE-developed resists (1987)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 33 (1987), S. 1585-1591 
    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: A novel plasma-developed resist lithographic process is described that uses compressed CO2 to extract nonvolatile siloxane molecules from host organic polymers. The process is capable of at least 0.75 μm resolution with an X-ray sensitive guest siloxane-host polymer system. A processing window was investigated and defined to eliminate or minimize film damage during compressed fluid extraction. Polymer deformation was usually avoided by using supercritical CO2 rather than liquid CO2, provided that film thicknesses were ≤1 μm. Increased solute concentrations in the host polymer also adversely affected the quality of extracted films. An in situ capacitance process monitoring scheme was developed which indicated that film damage, when observed, was primarily caused by explosive decompression of the solvent from the host polymer.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690331002
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  • 8
    Electronic Resource
    Electronic Resource
    Helix-coil stabilities of L-alanine and L-leucine in mixed organic solvents (1977)
    New York : Wiley-Blackwell
    Biopolymers 16 (1977), S. 2565-2568 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1977.360161117
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  • 9
    Electronic Resource
    Electronic Resource
    Molecular and crystal structure of an intercalation complex: Proflavine-cytidylyl-(3′,5′)-guanosine (1979)
    New York : Wiley-Blackwell
    Biopolymers 18 (1979), S. 2405-2429 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The high-resolution crystal and molecular structure of a 3:2 complex of proflavine and cytidylyl-(3′,5′)-guanosine is described. The complex exhibits more than one mode of dye binding to the dinucleoside phosphate. One proflavine cation is symmetrically intercalated between the base pairs. The other proflavine cations and ones related by symmetry stack above and below the base pairs and also hydrogen bond externally to the duplex. The conformation of the CpG is most similar to A-RNA with all C(3′)-endo sugar puckering. To allow the base pairs to stretch from the normal 3.4-Å separation to a 6.8-Å separation, the torsion angles φ and χ of the guanosine are increased by about 60° from the values found in RNA. The crystal structure itself contains disordered sulfate anions and is highly solvated, with all but one water molecule involved in a continuous water-sulfate channel.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1979.360181004
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  • 10
    Electronic Resource
    Electronic Resource
    Evaluation of the influence of process factors on plasma developed X-ray resist properties (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 1029-1038 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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: UV spectroscopy, gel permeation chromatography (GPC) and liquid chromatography (LC) have been used to analyze process factors that influence the properties of PDXR-2 plasma developed X-ray resist comprised of 92.5 wt percent poly(2,3-dichloro-1-propyl acrylate) and 7.5 wt percent bis-acryloxybutyltetramethyldisiloxane (BABTDS). The GPC-LC method is particularly useful in optimizing fixing conditions, determining monomer concentration in the film, and studying molecular processes caused by absorbed X-rays and thermal effects during fixing. Evidence for a synergistic sensitivity enhancement resulting from fixing and exposure is presented. Optimally processed O2 reactive-ion etch developed patterns exhibit a microgranular texture in both exposed and unexposed regions of 〈500 Å size. Unexposed region texture consists of SiO2 resulting from the BABTDS monomer. It is completely removed by reactive ion etching with CHF3 for short times at low power. The exposed area texture is not removed and affords an edge roughness per line edge of 〈500 Å. Resolution appears mask limited while granular size is dependent on exposure time. A 20 sec exposure optimizes resolution, pattern uniformity, and granularity. 0.5 μm line and space resolution can be obtained with the X-ray machine and masks currently in use.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760231811
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