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  • 1980-1984  (4)
  • 1940-1944
  • Inorganic Chemistry  (3)
  • Sewage ponds  (1)
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 72 (1980), S. 21-30 
    ISSN: 1573-5117
    Keywords: Sewage ponds ; BOD-removal ; stability ; Daphnia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract By arranging sewage ponds in series, some feedback relationships within the food web are disconnected, but stability may increase. This particularly applies to a persistent ‘clearwater-state’ in the last cell caused by mass growths of Daphnia or other zooplankton in the absence of fish. Microbial pollution in this case is reduced to a level which may permit nearly unrestricted irrigation. The oxygen balance of lagoons is, apart from the diurnal cycle, subject to substantial temporal variations. This also applies to continuous-flow laboratory models with a constant (BOD-load, temperature) or a constant-cycle (light) chemical and physical environment. An example is given illustrating a high adjustment stability of a lagoon in consequence of a catastrophic perturbation. The strong tendency of lagoons towards an oligomictic behaviour is promoted by thermal stratification and by a vertical gradient in the metabolic activity (oxidation/reduction potential). The hydrodynamic conditions oscillate between plug flow in periods of convective overturn and short-circuiting if thermal stratification has developed. Nevertheless, the average performance (BOD removal) for a particular season could be calculated with a reasonable accuracy. As a basis for this calculation, nomographs were developed from which the rate coefficient K1 of BOD removal for a given combination of residence time and BOD load can be read.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 463 (1980), S. 149-154 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Silylphosphane Transition Metal Complexesme2Si[P(Sime3)(Cme3)]2 1 reacts with Ni(CO)4to produce5 (two isomeric forms 1:1). The compounds 6 and7 are synthesized by reacting the cyclic silylphosphanes 2 and 3 with Ni(CO)4 and Cr(CO)5 THF, respectively. The dinuclear complex 8 is obtained by the reaction of two moles of Ni(CO)4 with3.
    Notes: me2Si[P(Sime3) (Cme3)]2 1 (me = CH3) reagiert mit Ni(CO)4 zu 5 (Konfigurationsisomere im Verh. 1:1). Die 1,3-Disila-2, 4-diphospha-cyclobutane 2 und 3 bilden mit Ni(CO)4 bzw Cr(CO)5. THF die Verbindungen 6 und 7. Die Umsetzung von 3 mit 2 Mol Ni(CO)4 führt zum Zweikernkomplex 8.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation, Structures, and Properties of Tris-hexamethyl-trisila-tetraphospha-nortricyclene-bis-chromiumtricarbonyl [P4(Sime2)3]3[Cr(CO)3]2Hexamethyl-trisila-tetraphospha-nortricyclene P4(Sime2)3 1 reacts with C6H6Cr(CO)3 or (CHT)Cr(CO)3 (CHT = Cycloheptatriene) under formation of [P4(Sime2)3]3[Cr(CO)3]2 3 (red crystals), in which each of the Cr atoms is attached to one P atom of a P3 ring of the three molecules 1. 3 can also be prepared by heating a solution of P4(Sime2)3Cr(CO)5 in benzene or THF up to 120-1307deg;C. The compound 3 crystallizes in an orthorhombic and a hexagonal form, the latter being stabilized by one mole toluene. As revealed by single crystal investigations, the symmetry ¯6, distances and angles are nearly unchanged. The o-form corresponds to a face centered cubic packing of the molecules, whereas the h-form is hexagonal close packed.
    Notes: Hexamethyl-trisila-tetraphospha-nortricyclen P4(Sime2)3 1 reagiert mit C6H6Cr(CO)3 bzw. (CHT)Cr(CO)3 (CHT = Cycloheptatrien) unter Bildung von [P4(Sime2)3]3[Cr(CO)3]2 3 (rote Kristalle), in dem jedes der Cr-Atome mit einem P-Atom eines P-Dreiringes der drei Moleküle von 1 verbunden ist. 3 bildet sich auch beim Erwärmen einer Lösung von P4(Sime2)3Cr(CO)5 in Benzol oder THF auf 120°-130°C.Die Verbindung 3 kristallisiert in einer orthorhombischen und einer durch ein Mol Toluol stabilisierten hexagonalen Form. Nach Einkristalluntersuchungen sind die Symmetrie ¯6, Abstände und Winkel in beiden Formen nahezu unverändert. Die o-Form entspricht einer kubisch dichten, die h-Form einer hexagonal dichten Molekülpackung.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 465 (1980), S. 59-71 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transition Metal Complexes of the Hexamethyl-trisila-tetraphospha-nortricyclene P4 (Sime 2) 3P4(Sime2)3 1 reacts with Mo(CO)6, Cr(CO)5THF, and Mn(η-C5H5)(CO)2THF to give crystalline complexes in which 1 functions as a monodentate ligand. In each compound one phophorus atom of the cyclotriphosphane ring coordinates to the metal atom. Using Mn(η-C5H5)(CO)2THF, two different P atoms of the P3 Cr(CO)4 norbornadiene and 1 react, yielding the dimeric, red, crystalline compound (CO) 4Cr[μ-P4(Sime2)3]2Cr(CO)4. In this complex the two molecules of 1 are both bonded by two P atoms of the P 3 ring to the two Cr(CO)4 Units, forming a six-memered (CrP2)2ring.
    Notes: Die Titelverbindung P4(Sime2)3 1 bildet mit Mo(CO)6, Cr(CO)5THF und Mn(η-C5H5)(CO)2THF kristalline Komplexverbindungen, in denen 1 als einzähniger Ligand mit einem P-Atom des P-Dreiringes as das Metall Koordiniert ist. Mit Mn(η-C5H5)(CO)2 THF lassen sich auch zwei Mn(η-C5H5)(CO)2-Gruppen an 1 koordinieren, Wobei die Bindung über je ein P-Atom des P-Dreiringes erfolgt. Mit Cr(CO)4-Norbornadien reagiert 1 unter Dimerisierung zum (CO)4Cr[μ-P 4(Sime3)3]2Cr(CO)4(rote Kristalle). Die beiden Moleküle von 1 sind ü ber je zwei P-Atome ihres P-Dreiringes durch zwei Cr(CO)4-Gruppen zu einem Sechsring Verbunden.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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