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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 259 (1981), S. 1003-1009 
    ISSN: 1435-1536
    Keywords: A flow ultramicroscope
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Zusammenfassung Die Arbeit stellt ein Gerät, geeignet für Teilchenzählung von einer Größenordnung bis 0.1 μm, vor. Es funktioniert auf Art eines Fließ-Ultramikroskops mit dem Unterschied, daß Teilchengrößenbestimmungen in dem Bereich von 0.1 bis 2.0 μm möglich sind, was mit anderen Geräten nicht der Fall ist. Die Teilchen fließen durch ein mit Laserlicht beleuchtetes Meßvolumen (Küvette). Das von ihnen gestreute Licht erzeugt Impulse, die mit Hilfe eines Photomultiplikators gezählt werden können. Die Intensität des von einem Teilchen gestreutes Licht hängt von dessen Größe ab und deshalb wird die Bestimmung einer Größenverteilung möglich. Die absolute Genauigkeit des Gerätes bestimmt man durch Vergleich mit einer engen Größenverteilung Polystyrol Latex. Ergebnisse zeigen, daß der Verlauf der Intensität in Abhängigkeit von Teilchengrößen mit der Theorie gut übereinstimmt.
    Notes: Summary A machine is described which will count particles or droplets in suspension in a liquid down to 0.1 μm and which is capable of size measurements between 0.1 μm and 2.0 ,μm. It works on the basis of the flow ultramicroscope. A stream of particles is passed through a laser beam and as each one passes a pulse of scattered light is produced. The pulses are detected by a photomultiplier and can be counted. Additionally the intensity of the pulses can be measured and a size distribution built up for the particles. The absolute accuracy of the machine has been checked by calibration against narrow size distribution polystyrene latexes and plots of intensity vs. size are found to conform with theory.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of solution chemistry 13 (1984), S. 103-119 
    ISSN: 1572-8927
    Keywords: Conductance ; Walden product ; tetraphenylarsonium and tetraphenylboride ions ; pyridine-water and acetonitrile-water mixtures ; alkali metal salts ; copper salts ; ion-solvent interactions ; structural effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The limiting conductance of various salts of Na+, Ag+, Cu+, Cu2+ and Ph4As+ in acetonitrile-water (AN-H2O) and pyridine-water (Py−H2O) mixtures are reported. Single ion values are calculated for AN-H2O mixtures using the TATB assumption [λo(Ph 4 As +) = λo(Ph 4 B −)]. The trends observed for the limiting Walden products (λoη) of the electrolytes and individual ions are discussed in terms of specific ion-solvent interactions and the structural effects of the solvent mixtures.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 22 (1976), S. 851-855 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Bench scale packed columns were used to study the kinetic behavior of biological denitrification. After tracer studies were run to determine flow characteristics, steady state nitrate profiles were determined. A first-order rate expression with an Arrhenius temperature dependence is an adequate model of the reaction for nitrate-nitrogen concentrations of 〈 100 mg/l and temperature of 5° to 20°C. The rate constants are proportional to the packing surface area.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 4
    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 correlation has been established between the dynamic storage modulus (E') and the mean cross polarization time constants 〈TCH〉 for a set of five morphologically diverse polymers, including one at two temperatures and one at two plasticizer concentrations. The correlation is only possible when the TCH values for all of the motional environments within the polymers are considered. An inversion recovery cross polarization (IRCP) NMR technique is used to obtain motional and morphological information from the main chain carbons of each polymer. After comparing simplified correlation functions for the two parameters, an experimental relationship between them is established that suggests that TCH and E' are both modulated by a similar distribution of molecular motions.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 46 (1992), S. 295-301 
    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: Samples of plasticized poly(vinyl butyral-co-vinyl alcohol) (PVB) are found to exhibit multiple thermal transitions as observed by dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC). Arrhenius plots using DSC and DMA data suggest that two of the transitions are glass-type ones. Variable temperature solid-state 13C-NMR experiments show a temperature-dependent line-broadening pattern for all PVB backbone carbons with maximum broadening at 55°C or at about 50°C above the second-order-type transitions α1 and α2 as measured by DSC. Using Arrhenius plots, the NMR transition is found to best correlate with α1, which is consistent with glass transition behavior. The solid-state NMR spectra also show that vinyl alcohol tacticity remains unresolved up to a temperature of about 95°C, beyond which line narrowing begins to occur. High-temperature thermal transitions are also observed by DSC and DMA, which suggest that the onset of motion involving vinyl alcohol sequences may be responsible for these transitions.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 52 (1994), S. 997-1004 
    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 effect of polymeric steric stabilizers on the dispersion stability of alumina was determined by settling experiments. The theoretical settling density was determined for alumina in a 90:10 wt% toluene-ethanol mixed solvent. Polymers evaluated were sulfonated polystyrenes, Shell's functionalized Kraton block polymers (styrene-hydrogenated diene), ICI's polymeric surfactants, homopolystyrene, a nonfunctionalized Kraton block polymer, and two Union Carbide Corporation silwet surfactants. The high-molecular-weight sulfonated polystyrene (60,000) containing a low level of sulfonation, functionalized Kraton block polymers, and one ICI polymeric surfactant were effective in improving the dispersion stability of the alumina. The percent of theoretical settling density for the “good” polymeric steric stabilizers ranged from 45 to 50%. The low-molecular-weight sulfonated polystyrene (10,000 MW), homopolystyrene, unfunctionalized Kraton block polymer, one ICI polymeric surfactant, and the silwet surfactants were ineffective in improving the dispersion stability of the alumina in the mixed solvent. © 1994 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 28 (1990), S. 301-306 
    ISSN: 0887-6258
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No Abstract
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 47 (1993), S. 1999-2003 
    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 sedimentation behavior of alumina powder has been studied in the presence of poly-vinylpyrrolidone (PVP) and poly(vinylpyrrolidone-co-vinyl acetate) (PVP/VA) in both thermodynamically “good” and “poor” solvents for the PVP homopolymer. PVP/VA provides higher sediment densities than does its PVP homopolymer counterpart. Solutionstate 13C-T1 spin-lattice relaxation measurements were made on analogous mixtures both with and without alumina powder. The NMR results suggest that the PVP/VA copolymer is anchored to the alumina powder surface by means of VA moieties, whereas the PVP moieties extend into the continuous phase of the slurry medium. Thus, the higher settling densities that are observed in the presence of PVP/VA can be attributed to a steric stabilization mechanism. © 1993 John Wiley & Sons, Inc.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 45 (1992), S. 391-398 
    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: Correlations between the macroscopic bulk polymer properties storage modulus (E′) and loss modulus (E″) and the microscopic property of cross-polarization as represented by the time constant TCH have been established for a series of polyurethane elastomers. The dependence of E′, E″, and TCH as a function of molecular weight, rigid domain concentration, and temperature are graphically presented as a series of log plots. An experimental relationship is presented that shows that the distribution of motions of the flexible domains appears to be the major factor in the success of these correlations.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 48 (1993), S. 677-681 
    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 relationship between dynamic storage modulus (E′) and the mean cross-polarization time constants 〈TCH〉 for 16 polymer data sets has been established by using a standard linear solid model. This model is used in an attempt to equate the process of cross-polarization with mechanical rigidity by virtue of the implicit dependence of each phenomenon on molecular motion. The apparent validity of the relationship between these parameters indicates that cross-polarization in polymers can be a function of molecular motion in addition to microscopic spin dynamics. The limitations as well as practical applications of this relationship are discussed. © 1993 John Wiley & Sons, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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