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  • Inorganic Chemistry  (83,671)
  • Aerodynamics
  • 11
    Electronic Resource
    Electronic Resource
    Springer
    The international journal of advanced manufacturing technology 14 (1998), S. 894-900 
    ISSN: 1433-3015
    Keywords: Aerodynamics ; Concurrent engineering ; Manufacturing costs ; Optimisation ; Statistical models ; Tolerances
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A component of the direct operating cost of aircraft is that associated with the manufacturing cost. This affects depreciation, interest, insurance and maintenance charges. By relaxing the requirements for aerodynamic surface smoothness the manufacturing cost can be reduced at the expense of an increase in drag and corresponding fuel costs. This work is part of a study to examine this multidisciplinary problem. Only isolated turbofan nacelles are considered. The costs associated with assigning different tolerance levels to the feature dimensions on nacelles are assessed. A statistical procedure is employed to estimate the cost-tolerance relationship for eleven features involving gaps, steps, surface profile and fastener flushness. This procedure requires actual manufacturing and cost source data. A knowledge of the cost-tolerance relationships is useful in a concurrent engineering context. It will allow aerodynamicists to optimise surface smoothness in consultation with production engineers, thus achieving the best compromise between cost and drag.
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Meccanica 34 (1999), S. 199-229 
    ISSN: 1572-9648
    Keywords: Aerodynamics ; Kutta condition ; Edge singularities ; Boundary integral equations ; Fluid dynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract This review paper presents a unified formulation of the Kutta condition for steady and unsteady flows, implemented by removing all unbounded velocity singularities (of power‐law and logarithmic type) at the trailing edge, and including nonlinear wakes and thick swept‐back wings. A suitable boundary integral approach is adopted and the uniqueness issue is discussed for several wing configurations of interest in aerodynamics. Sommario. Si presenta una formulazione unificata della condizione di Kutta per flussi stazionari e non stazionari, ottenuta imponendo la limitatezza della velocità al bordo d'uscita, e valida nel caso nonlineare anche per ali a freccia. Si utilizza un opportuno approccio integrale al contorno e si discute il problema dell'unicità per svariate configurazioni alari di interesse nelle applicazioni.
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 167 (1990), S. 145-154 
    ISSN: 1432-1351
    Keywords: Moth ; Flight ; Migration ; Kinematics ; Aerodynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Air speeds and wing kinematics were determined for the Neotropical moth Urania fulgens in natural migratory flight over Lake Gatun, Republic of Panama. Morphological parameters are presented for the same insects filmed in free flight. A quasi-steady aerodynamic analysis was used to show that unsteady mechanisms of lift generation are probably not necessary to produce the forces necessary for fast forward flight. Mechanical power requirements of forward flight were estimated from the biomechanical and morphological data. Over an airspeed range of 1.5 to 4.5 m/s, the mechanical power required to fly is predicted to increase dramatically with forward speed. A comparison of estimated metabolic rates with endogenous lipid reserves suggests that U. fulgens feeds extensively on flower nectar during migration from Central into South America.
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Journal of mathematical biology 24 (1986), S. 1-24 
    ISSN: 1432-1416
    Keywords: Aerodynamics ; Pollination ; Ephedra ; Computer simulations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract Computer simulations are used to predict the behavior of pollen grains with different physical properties within the acceleration field created around the ovules of the gymnosperm Ephedra trifurca. A modelling procedure is given that (1) calculates the number of pollen grains captured by an ovule's pollination-droplet and (2) gives a correlation between pollination efficiency and the physical properties (= mass, size) of different types of pollen. Based on this procedure, the number of Ephedra pollen grains captured by micropyles can be less than the number captured from other species. However, the mass and size of Ephedra pollen grains appear to coincide with those predicted to yield a local maximum of pollination efficiency, i.e. slightly larger or smaller values of either mass or size would decrease the probability of capture. In addition, the properties of Ephedra pollen grains operate synergistically in the aerodynamic environment around ovules and are focused to collide with pollination-droplets. By analogy, the properties of Ephedra pollen coincide with those predicted for a localized “adaptive peak”. The physical properties of pollen grain types other than E. trifurca that can maximize pollen capture are not generally represented in the aerobiology of Ephedra during the pollination season. Therefore, the phenology of pollen release, community taxonomic-composition, and the physics of particle capture play collectively important roles in the reproductive success of Ephedra trifurca.
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  • 15
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 92 (1959), S. 1018-1027 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bei nochmaliger Untersuchung der Umsetzung von CCl4 mit Si/Cu-Gemischen werden, wie bereits bekannt, SiCl4, C2Cl4 und Si2Cl6 gefunden. Darüber hinaus lief eine direkte Synthese. Sie führte wahrscheinlich zur Bildung des allerdings dabei nicht nachgewiesenen Cl3C·SiCl3. Dagegen wurde die nach der direkten Synthese entstandene Verbindung C(SiCl3)4 erstmalig aufgefunden.  -  Die Entstehung der ebenfalls nachgewiesenen Verbindungen Cl3SiC·C⋮CC·SiCl3 und Cl3SiC·(Cl)C:C(Cl)C·SiCl3 wird durch Dechlorierungen des Cl3CC·SiCl3 mit Kupfer erklärt.  -  Für die neuen Verbindungen wurden Strukturbeweise geführt. Es wurden C2Cl4 und Cl3CC·SiCl3 mit Si/Cu-Gemischen umgesetzt. Die letzte Umsetzung ergab dieselben Reaktionsprodukte wie das CCl4, so daß auch bei diesem eine direkte Synthese über das Cl3CC·SiCl3 glaubhaft gemacht ist.
    Additional Material: 2 Ill.
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  • 16
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 92 (1959), S. 1048-1055 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Eigenschaften von tert.-Butylthionitrit, Triphenylmethylthionitrit und tert.-Butylthionitrat werden Rückschlüsse auf die Elektronenstruktur der schwefelhaltigen Gruppe gezogen.
    Additional Material: 2 Tab.
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  • 17
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Als weiteres Beispiel für die präparative Überlegenheit der säurekatalysierten Aldolreaktionen des Formaldehyds gegenüber den OH⊖-katalysierten wird über die Synthese der bisher unbekannten Bisanhydro-ennea-heptose, die das Ringsystem des 3.7-Dioxa-bicyclo-[1.3.3]-nonans enthält, berichtet.  -  Bei der Untersuchung des Verhaltens der Bisanhydro-ennea-heptose gegen Alkalien machten sich in der Abspaltbarkeit der Hydroxymethylgruppen charakteristische Unterschiede geltend, deren Erklärung in den konstitutionell-konstellativen Gegebenheiten zu suchen ist.  -  Bei dem Versuch einer Ringerweiterung an der Anhydro-ennea-heptose mit Diazomethan bildet sich eine Verbindung C9H16O5, die wahrscheinlich kein Derivat des Oxa-cycloheptanons-(4), sondern ein Derivat des Tetrahydro-γ-pyrons ist.
    Additional Material: 4 Ill.
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  • 18
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 92 (1959), S. 1092-1101 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Substituierte Ammoniumsalze vom Typ I liefern mit Abkömmlingen des Phenylglyoxals in Methanol in glatter Reaktion Lactolid-Basen vom Typ II. Aus diesen lassen sich verschiedene Octa- bzw. Decahydroisochinolin-Derivate darstellen, die in 1-Stellung einen substituierten Benzylrest tragen.
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  • 19
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 92 (1959), S. 1115-1117 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die jodometrische Bestimmung der Hydroperoxyde von Benzolkohlenwasserstoffen kann durch katalytische Wirkung von Kupferionen verbessert werden.
    Additional Material: 1 Ill.
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  • 20
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 92 (1959), S. 1135-1139 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Umsetzung von Tetraacetyl-α-D-glucopyranosylbromid und Tetraacetyl-6-trityl-β-D-glucopyranose mit Silberperchlorat oder Silberfluoroborat in Nitromethan liefert in guter Ausbeute Octaacetyl-β-gentiobiose. Die gleiche Umsetzung mit einem Überschuß an Tetraacetyl-α-D-glucopyranosylbromid und Silberperchlorat führt zur Octaacetyl-α-gentiobiose. Es wird eine Deutung des Reaktionsablaufs gegeben.
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