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  • 1
    Electronic Resource
    Electronic Resource
    A metastable ion study of the electron impact fragmentation of some substituted 2,6-pyrido-containing crown ethers (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 22 (1987), S. 633-636 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Extensive networks of metastable ions link the major peaks in the electron impact mass spectra of two crown ethers containing 2,6-pyrido units. High-resolution mass measurements and the metastable peaks allow the elucidation of the fragmentation pathways. The spectra are influenced more by the presence of aromatic substituents than by the 2,6-pyrido units.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210220911
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  • 2
    Electronic Resource
    Electronic Resource
    Small-angle light scattering in dense microemulsions, transition from droplet to bicontinuous phase (1994)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 16 (1994), S. 1627-1633 
    Details
    ISSN: 0392-6737
    Keywords: Brillouin and Rayleigh scattering ; Liquids ; Emulsions and suspensions ; Order-disorder and statistical mechanics of model systems ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary We have performed extensive small-angle light scattering (SALS) measurements on a three-component microemulsion (AOT/decane/water) as a function of the dispersed phase concentration and the temperature. All samples have a water/AOT molar fractionw=40.8. Such a system presents a very complex phase diagram with many structural configurations. With the SALS technique, we have been able to observe all the phase separation lines. In particular we give details on the system structure on the percolation phenomenon and on the bicontinuous phase recently observed. In particular we show that the percolation is driven by a long-scale aggregation between microemulsion droplets.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02462051
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  • 3
    Electronic Resource
    Electronic Resource
    Small-angle light scattering studies of dense AOT-water-decane microemulsions (1996)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 18 (1996), S. 1317-1332 
    Details
    ISSN: 0392-6737
    Keywords: Brillouin and Rayleigh scattering ; other light scattering ; Emulsions and suspensions ; Specific phase transitions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary We have performed extensive studies of a three-component microemulsion system composed of AOT-water-decane (AOT=sodium-bis-ethylhexyl-sulfosuccinate is an ionic surfactant) using small-angle light scattering (SALS). The small-angle scattering intensities are measured in the angular interval 0.001–0.1 radians, corresponding to a Bragg wave number range of 0.14 μm−1〈Q〈〈1.4 μm−1. The measurements were made by changing temperature and volume fraction ϕ of the dispersed phase (water + AOT) in the range 0.05〈ϕ〈0.75. All samples have a fixed water-to-AOT molar ratio,w=[water]/[AOT]=40.8, in order to keep the same average droplet size in the stable one-phase region. With the SALS technique, we have been able to observe all the phase boundaries of a very complex phase diagram with a percolation line and many structural organizations within it. We observe at the percolation transition threshold, a scaling behavior of the intensity data. This behavior is a consequence of a clustering among microemulsion droplets near the percolation threshold. In addition, we describe in detail a structural transition from a droplet microemulsion to a bicontinuous one as suggested by a recent small-angle neutron scattering experiment. The loci of this transition are located several degrees above the percolation temperatures and are coincident with the maxima previously observed in shear viscosity. From the data analysis, we show that both the percolation phenomenon and this novel structural transition are derived from a large-scale aggregation between microemulsion droplets.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02453266
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  • 4
    Electronic Resource
    Electronic Resource
    Quantitative analysis of the molecular species of monosialogangliosides by continuous-flow fast-atom bombardment mass spectrometry (1991)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 5 (1991), S. 618-621 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Negative-ion continuous-flow fast-atom bombardment mass spectroemtry was evaluated asa means for the quantitative analysis of N-acetylneuraminyl-galactosyl-glucosyl ceramide (NeuAc-GM3) and N-acetylgalactosaminyl-(N-acetylneuraminyl)galactosyl-glucosyl-ceramide (NeuAc-GM3). This study was carried out on a 7070-EQ mass spectrometer (VG Analytical, Manchester, UK) using a home-made continuous-flow fast-atom bombardment probe with a mixture of methanol +water+triethanolamine (70:27:3, v/v/v)as the mobile phase. Utilizing 100 ng of acetyl-lysogalactosyl-N-acetylgalactosaminyl-(N-acetylneuraminyl)galactosyl-glucosylceramide (acetyl-lysoGM1) as an internal standard curves for NeuAc-GM3 d18:1-16 0, NeuAc-GM3 d18:1-18:0 and Neuac-GM3 d18:1-18:0 were found to be linear over the range 5-250ng, with associated correlation coefficients of 0.990-0.997. The lower limit of detection was found to be 2.5ng. Satisfactory results could also de obtained when the calibration curves were derived from the deprotonated molecular ions of a mixture of the NeuAc-M2 and NeuAc-GM3 classes. Using this approach, quantitative determination of NeuAc-GM3 d18:1-16:0 from rat adrenal gland was performed sing N-acetylneuraminic acid assay as a test control. We found 278±36 ng of this species in 1 mg of tissue (three replicate experiments). The procedure represents a senstive method for the quantitation of mionosialogangliosides and its capability to give molecular species information.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290051210
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  • 5
    Electronic Resource
    Electronic Resource
    Analysis and experimental study of gas penetration in a gas-assisted injection-molded spiral tube (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 58 (1995), S. 793-799 
    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: Characteristics of gas penetration and polymer melt flow in gas-assisted injection molded spiral tubes was investigated by simulations and experiments. Distribution of the skin melt thickness along the gas flow direction was measured, and gas penetration in the primary and secondary stages was identified. An algorithm based on the control-volume/tiniteelement method combined with a particle-tracing scheme using a dual-filling-parameter technique is utilized to predict the advancements of both melt front and gas from during the molding process. The simulated distribution of gas penetration shows reasonably good coincidence with experimental observations. © 1995 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1995.070580412
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  • 6
    Electronic Resource
    Electronic Resource
    Numerical simulation of semicrystalline polymer flowing in an empty tube with solidification (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 724-731 
    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: A methodology is set forth for the numerical solution of the transient freezing problem of a viscous power-law fluid flowing in a cold empty tube with a frozen layer forming on the inside tube surface. The fluid considered is the melt of a semicrystalline polymer with temperature dependent viscosity. The solution domain encompasses both the liquid and solid phases. Coordinate transformations are employed to immobilize and to straighten the moving, curved interface. An implicit finite difference method is employed to solve the governing equations. Numerical results are analyzed by examining the effects of the Peclet number, Nahme number, Stefen number, and the power law index on the profiles of the frozen layer. Variations of the thickness of the frozen layer as a function of time and axial coordinate are also presented.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760321104
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  • 7
    Electronic Resource
    Electronic Resource
    Fickian diffusion of alkanes through glassy polymers: Effects of temperature, diffusant size, and polymer structure (1980)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 20 (1980), S. 40-50 
    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: Diffusivities D ranging over six orders of magnitude with values as low as 2 × 10-13 cm2/s have been obtained by a recently developed permeation apparatus, employing a gas-flow method and a flame ionization detector; Log D for hydrocarbons in bisphenol-A polycarbonate (PC) at 120°C is proportional to the square of the molecular diameter (d2) as given by the Lennard-Jones 6-12 potential. This correlation holds even for the nonspherical n-hexane molecule. The activation energy for diffusion is also linearly related to d2, with values of 9.5 and 23 kcal/mol for methane and neopentane in PC, respectively. Comparison of PC with two similar polymers of higher glass-transition temperatures (Tg) indicates that our diffusion data do not correlate with the Tg of these polymers. The presence of subsidiary transitions, however, appears to enhance segmental mobilities, increasing the rate of diffusion of the hydrocarbons. The thermodynamic solubility of alkanes in glassy PC can be directly related to their boiling points, and in addition, their enthalpy of solution is linearly related to the heat of condensation of these permeants.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760200108
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  • 8
    Electronic Resource
    Electronic Resource
    Morphology and mechanical properties of injection-molded specimens of two-phase polymer blends (1977)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 21 (1977), S. 353-370 
    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: An experimental study was carried out to investigate the moldability of polymer blends which form two phases in the molten state and the effect of mixing on the morphology and mechanical porperties of molded specimens. Blends of polystyrene with polypropylene and blends of polystyrene with high-density polyethylene were used for this study. A plunger-type injection molding machine (Van Dorn) was employed for molding specimens. To improve the mixing performance of the plunger machine, a Static Mixer (Kenics Corp., Super Nozzle) was installed between the heating cylinder and the sprue. A number of different molding conditions (injection pressure, temperature, injection time, cooling time) were varied, and molded specimens were collected under each molding condition. The specimens were used for studying the degree of dispersion in the blends and for determining the mechanical properties. A differential thermal analysis (DTA) experiment was also carried out to determine the degree of dispersion of the blends in molded specimens. It was found that a linear correlation exists between the blend composition and thermal spectra area of the blends tested.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1977.070210205
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  • 9
    Electronic Resource
    Electronic Resource
    Experimental investigation of the polymer melt flow during injection post-filling process (1995)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 41 (1995), S. 2661-2663 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690411217
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  • 10
    Electronic Resource
    Electronic Resource
    Study of polymer melt flow in sequential injection molding process (1996)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 42 (1996), S. 1706-1714 
    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: Experimental studies of polymer melt flow in the filling and post-filling stages of the injection molding process were performed using the sequential injection of transparent and colored polystyrene resin. Effects of fountain flow in the filling stage, geometrical factors caused by edges and corners, as well as flow through contractions and expansions, were identified. Significant polymer melt flow which increases with increased packing pressure was observed in the post-filling process. The melt flow is more concentrated around the gate area than away from the gate. It was also found that the polymer melt flows across the gap center, resulting in partial annihilation of the weld line. Simulations based on the control-volume/finite-element method employed within each gapwise layer combined with the dual-filling-parameter technique were developed to trace the advancements in melt fronts for both skin and core materials. Numerical simulations show reasonable consistency with experimental results in both skin and core material distribution. If the edge effect is taken into account using a shape factor as a geometrical correction, the simulation accuracy is further improved.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690420622
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