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  • 1
    Electronic Resource
    Electronic Resource
    Barotropic-Baroclinic instability of mean zonal wind during summer monsoon (1977)
    Springer
    Pure and applied geophysics 115 (1977), S. 1449-1461 
    Details
    ISSN: 1420-9136
    Keywords: Monsoon ; Mean zonal wind ; Barotropic-baroclinic instability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Barotropic-Baroclinic instability of horizontally and vertically shearing mean monsoon flow during July is investigated numerically by using a 10-layer quasi-geostrophic model. The most unstable mode has a wavelength of about 3000 km and westward phase speed of about 15 m sec−1. The most dominant energy conversion is from zonal kinetic energy to eddy kinetic energy. The structure of the most unstable mode is such that the maximum amplitude is concentrated at about 150 mb and the amplitude at the lowest layers is negligibly small. Barotropic instability of the zonal flow at 150 mb seems to be the primary excitation mechanism for the most unstable mode which is also similar to the observed westward propagating waves in the upper troposphere during the monsoon season. The results further suggest that Barotropic-Baroclinic instability of the mean monsoon flow cannot explain the occurrence of monsoon depressions which have their maximum amplitude at the lower levels and are rarely detected at 200 mb.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00874418
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  • 2
    Electronic Resource
    Electronic Resource
    Wäßrige Polymerisation von Acrylamid mit dem sauren Redoxsystem Perman-Banat/Thioharnstoff (1975)
    Springer
    Colloid & polymer science 253 (1975), S. 337-337 
    Details
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02352128
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  • 3
    Electronic Resource
    Electronic Resource
    Dispersion in non-Newtonian fluids: Effects of chemical reaction (1979)
    Springer
    Rheologica acta 18 (1979), S. 740-748 
    Details
    ISSN: 1435-1528
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Zusammenfassung Die Verteilung eines gelösten Stoffes in nicht-newtonschen Flüssigkeiten, die durch Kanäle und Rohre fließen, wird unter Zugrundelegung einer homogenen chemischen Reaktion erster Ordnung untersucht. Es wird gezeigt, daß bei gleicher mittlerer Strömungsgeschwindigkeit der äquivalente Verteilungskoeffizient abnimmt, wenn die Reaktionsgeschwindigkeit zunimmt. Diese Abnahme wird bei nicht-newtonschen Flüssigkeiten noch verstärkt.
    Notes: Summary The dispersion of a solute in non-Newtonian fluids flowing through channels and pipes has been studied by taking into account the homogeneous first-order chemical reaction. It is shown that for the same mean velocity of the flow the equivalent dispersion coefficient decreases as the rate of the chemical reaction increases. This decrease is enhanced due to non-Newtonian nature of the fluid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01533349
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  • 4
    Electronic Resource
    Electronic Resource
    Synthesis of thermally stable polyamide hydrazides (1979)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 17 (1979), S. 4129-4133 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; 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
    URL: http://dx.doi.org/10.1002/pol.1979.170171234
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  • 5
    Electronic Resource
    Electronic Resource
    Aqueous polymerization of acrylamide initiated by acidic potassium permanganate-ascorbic acid redox system (1973)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 11 (1973), S. 751-762 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polymerization of acrylamide initiated by the acidic permanganate-ascorbic acid redox pair has been studied in aqueous media at 30 ± 0.2°C in nitrogen atmosphere. The initial rate of polymerization has been found to be proportional to nearly the first power of the catalyst KMnO4 concentration within the range 6.0 × 10-3-14.0 × 10-3 mole/l. The rate is proportional to the first power of the monomer concentration within the range 4.00 × 10-2-12.0 × 10-2 mole/l. However, the rate of polymerization is independent of ascorbic acid concentration within the range 3.0 × 10-3-6.0 × 10-3 mole/l., but the further increase of the concentration depresses the rate of polymerization as well as maximum conversion. The initial rate increases but the maximum conversion decreases as the temperature is increased within the range 20-35°C. The overall energy of activation has been found to be 9.8 kcal/mole. The optimum amount of sulfuric acid is essential to initiate the polymerization but its presence in excess produces no effect either on the rate of reaction or the maximum conversion. Water-miscible organic solvents and salts, e.g., CH3OH, C2H5OH, (CH3)2CHOH, KCl, and Na2SO4, depress the rate. Slight amounts of MnSO4 · H2O and a complexing agent NaF increase the rate of polymerization. Cationic and anionic detergents have been found to decrease and increase the rate, respectively, while nonionic surfactants have no effect on the rate of polymerization.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1973.170110405
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  • 6
    Electronic Resource
    Electronic Resource
    Aqueous polymerization of acrylamide (1979)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 17 (1979), S. 531-538 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polymerization of acrylamide (I) initiated by a potassium bromate - thioglycollic acid (TGA) redox pair has been studied in aqueous media at 30°C in a nitrogen atmosphere. The reaction order related to the catalyst concentration (KBrO3) was 0.501, which indicated a bimolecular mechanism for the termination reaction in the range of 1.0-3.0 × 10-3 mole/liter. The polymerization rate varied linearly with monomer (I) concentration over the range of 1.0-5.0 × 10-2 mole/liter. A typical behavior is observed, however, by changing the thioglycollic acid concentration. The initial rate of polymerization (Ri), as well as the maximum conversion, increases by increasing the temperature to 30°C, but the initial rate and the maximum conversion falls as the temperature rises above 30°C. The overall energy of activation is 6.218 kcal in the temperature range of 20-40°C. Water-miscible organic solvents, namely, CH3OH and C2H5OH, depress the rate of polymerization.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1979.170170222
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  • 7
    Electronic Resource
    Electronic Resource
    Aqueous polymerization of acrylamide initiated by acidic thiourea/potassium bromate redox systemOn the 60th birthday of Professor Dr. H. KäMMERER (1972)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 158 (1972), S. 9-19 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Es wurde die mit Kaliumbromat/Thioharnstoff ausgelöste Redoxpolymerisation von Acrylamid in wäßrigen, sauren Medien bei 25 ± 0,2°C unter Stickstoffatmosphäre untersucht.Die Polymerisationsgeschwindigkeit ist im Bereich von 0,75·10-2 bis 2,0·10-2 mol·l-1 von der 1. Potenz der Kaliumbromatkonzentration und im Bereich von 2,85·10-2 bis 8,55·10-2 mol·l-1 annähernd von der 1. Potenz der Chlorwasserstoffkonzentration abhängig. Von der Thioharnstoffkonzentration ist die Polymerisationsgeschwindigkeit jedoch unabhängig; im Bereich von 6,0·10-2 bis 10,0·10-2 mol·l-1 ist sie hingegen von der 1. Potenz der Konzentration des Monomeren abhängig. Im Bereich von 19 bis 35°C nimmt die Startgeschwindigkeit mit steigender Temperatur zu, der maximale Umsatz hingegen ab.Die gesamte Aktivierungsenergie beträgt im genannten Temperaturbereich 22,9 kcal·mol-1. Mit Wasser mischbare, organische Lösungsmittel sowie mono- und dibasische Salze haben dieselbe Wirkung, wie sie von MISRA et al. beobachtet wurde. Kationische und anionische Netzmittel erhöhen bzw. erniedrigen die Polymerisationsgeschwindigkeit (Rp), während neutrale Netzmittel keine Wirkung haben.
    Notes: The aqueous polymerization of acrylamide initiated by bromate/thiourea redox system has been studied in acidic media at 25 ± 0.2°C in a nitrogen atmosphere.The rate of polymerization has been found to vary with the first power of the potassium bromate concentration within the range 0.75·10-2 to 2.0·10-2 mole·1-1 and nearly with the first power of the hydrochloric acid concentration within the range 2.85·10-2 to 8.55·10-2 mole·1-1. However, the rate of polymerization is independent of the thiourea concentration, but varies with the first power of the monomer concentration within the range 6.0·10-2 to 10.0·10-2 mole·1-1. The initial rate increases but the maximum conversion decreases as the temperature increases within the range 19 to 35°C.The over all energy of activation has been found to be 22.9 kcal·mole-1 within the temperature range mentioned above. Water miscible organic solvents and mono- and dibasic salts show the same effect as given by MISRA et al. The effect of cationic and anionic surfactants has been found to increase and decrease the rate of polymerization (Rp) respectively, however non-ionic detergents have no effect on the (Rp).
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1972.021580102
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  • 8
    Electronic Resource
    Electronic Resource
    The effects of surfactants on homogeneous polymerization of acrylic monomers in aqueous media (1970)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 134 (1970), S. 179-192 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Wirkung von oberflächenaktiven Stoffen (nicht-ionischen, anionischen und kationischen) auf die homogene Polymerisation von Acrylsäure (30°C), Methacrylsäure (35°C) und Acrylamid (35°C) wurde untersucht. Die vergleichenden Geschwindigkeitsuntersuchungen, die bei Konzentrationen unter und über der kritischen Micellarkonzentration in Gegenwart von Triton X-100, Jadinol PU, Cetylpyridiniumbromid, Cetyltrimethylammoniumbromid und Laurylpyridiniumchlorid durchgeführt wurden, zeigten, daß die oberflächenaktiven Stoffe einen stark unterschiedlichen Einfluß auf die genannten Polymerisationssysteme ausüben. Das wird damit erklärt, daß die Absorption von Ionen aus der wäßrigen Phase an der Oberfläche der entgegengesetzt geladenen Micellen, die wahrscheinlich durch elektrostatische Anziehung hervorgerufen wird, die Bildung der reaktiven Spezies bestimmt, welche die Polymerisationsgeschwindigkeit in charakteristischer Weise beeinflussen. Abgesehen von COULOMBschen Kräften wird die Geschwindigkeit auch durch die Hydratation der hydrophilen Makromoleküle bestimmt. Ein Ansteigen des pH-Wertes des Reaktionsmediums mit steigender Konzentration an anionischer Seife stützt die Ansicht, daß die H-Ionen bevorzugt an der Grenzfläche der anionischen Micellen adsorbiert werden. Es wurde gezeigt, daß neutrale Seife unwirksam ist, wenn die Seifenkonzentration weit unter der kritischen Micellarkonzentration liegt.
    Notes: The effects of surfactants (non-ionic, anionic, and cationic) on the homogeneous polymerization of acrylic acid, methacrylic acid, and acrylamide were studied at 30, 35, and 35°C, respectively. The comparative rate studies, in the presence of Triton X-100, Jadinol PU, cetyl pyridinium bromide, cetyl trimethyl ammonium bromide, and lauryl pyridinium chloride at the concentrations below and above critical micellar concentration (CMC), reveal that the surfactants exerted a widely varying degree of influence on these systems of polymerization. Adsorption of ions from the aqueous phase onto the surface of oppositely charged micelles, presumably due to electrostatic attraction between them, governs the generation of reactive species thereby causing typical influences on the rate. Besides coulombic forces, the rate is also governed by the hydration factor of the hydrophilic macromolecules. Increase in pH of the medium with increasing concentration of anionic soap has provided a support to the view that the preferential adsorption of H⊕ ions may occur at the interface of anionic micelles. Neutral soap has been shown to be impotent when the soap concentration remained much below CMC.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1970.021340116
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  • 9
    Electronic Resource
    Electronic Resource
    Aqueous polymerization of acrylamide initiated by acidic permanganate/thiourea redox system (1973)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 173 (1973), S. 91-99 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die mit dem Redoxsystem saures Permanganat/Thioharnstoff ausgelöste Polymerisation von Acrylamid wurde in Wasser bei 30 ± 0,2 °C und unter Stickstoff untersucht. Die Polymerisationsgeschwindigkeit (Rp) ist der Konzentration von Kaliumpermanganat (Katalysator) im Bereich von 0,5 · 10-2 bis 1,40 · 10-2 mol dm-3 nahezu proportional und unabhängig von der Thioharnstoffkonzentration. Sie ist weiterhin proportional der Salzsäurekonzentration im Bereich von 2,85 · 10-2 bis 11,4 · 10-2 mol dm-3 und steigt mit der Monomerknozentration im Bereich von 2,5 · 10-2 bis 12,5 · 10-2 mol dm-3 linear an, um bei höherer Konzentration wieder abzufallen. Sowohl die Anfangsgeschwindigkeit der Polymerisation (Ri) als auch der höchste Umsatz nehmen bis 35 °C mit steigender Temperatur zu, aber der maximale Umsatz nimmt bei noch höherer Temperatur ab. Im Temperaturbereich von 25 bis 45 °C beträgt die Aktivierungsenergie der gesamten Reaktion 47,70 kJ mol-1 (11,48 kcal mol-1). Mit Ausnahme von Mangan(II)salzen bewirkt das Zufügen von Salzen eine Senkung von Rp und vom maximalen Umsatz. Kationische und anionische Netzmittel steigern bzw. vermindern Rp wohingegen die neutralen Netzmittel Rp nicht beeinflussen.
    Notes: The polymerization of acrylamide, initiated by acidic permanganate/thiourea redox system, was studied in aqueous media at 30 ± 0,2 °C in nitrogen. The rate of polymerization (Rp) was found to be proportional to nearly the first power of the catalyst (KMnO4) concentration, within the range of 0,5 · 10-2 to 1,4 · 10-2 mol dm-3, and independent of the thiourea concentration. However, the rate of polymerization varies with the first power of the hydrochloric acid concentration within the range of 2,85 · 10-2 to 11,4 · 10-2 mol dm-3, and increases linearly up to certain extent by varying the monomer concentration from 2,5 · 10-2 to 12,5 · 10-2 mol dm-3. A deviation from the linear behaviour is observed, however, above a concentration of 12,5 · 10-2 mol dm-3.The initial rate of polymerization (Ri) as well as the maximum conversion increases by increasing the temperature up to 35 °C, but the maximum conversion falls as the temperature rises above 35 °C. The overall energy of activation is found to be 47,70 kJ mol-1 (11,48 kcal/mol-1) within the temperature range of 25-45 °C. Addition of salts, except manganous salts, was found to be associated with a depression in the Rp and maximum conversion. The effect of cationic and anionic surfactants has been found to increase and decrease the Rp respectively; non-ionic detergents, however, have no effect on the Rp.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1973.021730106
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  • 10
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    Wäßrige Polymerisation von Acrylamid mit dem sauren Redoxsystem Perman-Banat/Thioharnstoff (1975)
    Springer
    Details
    Publication Date: 1975-04-01
    Print ISSN: 0372-820X
    Electronic ISSN: 1435-1536
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Springer
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