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Showing 1 to 20 of 125 for “"Ziegler"”.
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Modifikace 2. Ziegler-Nicholsovy metody pro případy, kdy metoda selhává.
… regulátoru na nastavenie jeho parametrov pomocou Ziegler-Nicholsovej frekvenčnej metódy v prípadoch kedy táto metóda zlyháva.
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Investigation of polymer grade blending in Ziegler-Natta Catalysed ethylene polymerisation systems
… operate on technology involving heterogeneous Ziegler-Natta catalysts. Plants often change operating conditions to produce different polymer grades; this allows them to cater to a larger polymer market. A side-effect of this practice is the unwanted formation of off-spec polymer during the …
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Organometallic Group 4 bis(borylamide) complexes as templates for Ziegler-Natta catalysis
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1997.
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Chelating polyamido complexes or rhenium, molybdenum, and hafnium : organometallic synthesis to Ziegler-Natta catalysis
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1998.
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Early transition metal complexes containing tridentate amido ligands : a systematic approach to Ziegler-Natta catalysis
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1999.
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Examination of Dynamic Processes in Living Ziegler-Natta Polymerization and New Polypropylene Architectures through Bimolecular Control
The cationic cyclopentadienyl zirconium acetamidinate (CPZA) complex {Cp*ZrMe[N(Et)C(Me)N(tBu)]}[B(Csub6 Fsub5)sub4], (Cp* = ηsup5-Csub5Mesub5) generated through activation of Cp*ZrMesub2[N(Et)C(Me)N(tBu)] via protonolysis of a methyl group with one equivalent of [PhNMesub2H][B(Csub6Fsub5)sub4], …
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Dust and Pleistocene Ice Ages: Eolian Sediments and Climate Change at Ziegler Reservoir, Snowmass Village, Colorado
<p>The discovery of the Ziegler Reservoir fossil site near Snowmass Village, Colorado presents an opportunity to examine subalpine ecosystem response, during a relatively unknown period, in which climate conditions were similar to present. Finegrained sediments at Ziegler Reservoir represent …
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Development of a computationally efficient model for the control of Ziegler-Natta catalysed industrial production of high density polyethylene
… alkenes, using heterogeneous titanium-based Ziegler-Natta catalysts. During grade transitions, when reactor conditions are manipulated to change polymer properties, significant quantities of off-specification product result. Implementing a model-predictive controller based on a dynamic …
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Avaliação das propriedades do polietileno de alta densidade produzido com catalisador Ziegler-Natta submetido à estrusão reativa com peróxidos orgânicos
… amostras de pó de PEAD produzido com catalisador Ziegler-Natta, para utilização em processamento por injeção, sopro ou extrusão de filmes, foram extrusadas com o peróxido de dicumila e o 2,5-dimetil-2,5-di(t-butilperoxi)-hexano em teores de 0,001 a 0,08 pcp. Os produtos obtidos foram …
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Polyenes by regioselective, living polymerization using molybdenum alkylidene bis(carboxylate) initiators and Ziegler-natta catalysis employing new zirconium diamido complexes
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1997.
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Observation of the first titanium alkyl/alkyl complexes: The key intermediate in the Ziegler-Natta mechanism for the polymerization of alkenes
… intermediate in the Cossee mechanism for Ziegler-Natta catalysis. Above $-$20$\sp\circ$C, the TiX$\sb2$(dmpe)$\sb2$ complexes catalyze the dimerization of ethylene to 1-butene with turnover rates of up to 440 hr$\sp{-1};$ the rates of ethylene dimerization vary according to the nature of …
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Hraðareglun 2 MW dísilrafstöðvar á Patreksfirði
… 2 MW dísilrafstöðvar. Rannsóknin beindist að Ziegler-Nichols aðferðinni ásamt reynslubundinni aðferð sem þróuð var af DEIF, framleiðanda stjórneiningarinnar. Ziegler-Nichols aðferðin byggir á fræðilegum grunni, á meðan aðferð DEIF byggir á hagnýtri reynslu. Markmiðið var að ákvarða hvor …
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Early transition metal catalysts for the living polymerization of olefins and alkynes
Zirconium and Hafnium Ziegler-Natta catalysts containing the [(2,6- C12C6H3NCH2CH2)2NMe]2- ([ArciN2NMe]2') ligand were prepared and employed in the polymerization of 1-hexene. Hafnium Ziegler-Natta catalysts containing the [(2,6- X2C6H3NHCH2)2C(CH3)(2-C5H4N)] ([Arx2NPy]2-) (X = Cl or F) ligand were …
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Studies of carbon-hydrogen and silicon-hydrogen bond activation by early transition metal complexes
… as catalysts for olefin polymerization in the Ziegler-Natta and Phillips processes. The key intermediates in these catalysts are thought to be six-coordinate metal alkyl/olefin complexes. The synthesis and study of early transition metal alkyl complexes as models of these catalytic centers can …
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The chemistry of manganese alkyls and aryls and of divalent titanium phenoxides
… oxidations by manganese-containing complexes and Ziegler-Natta olefin polymerizations, respectively.
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A Hysteresis Model for Reinforced Concrete Space Frame Structures
… Otani's modification of the Clough model and the Ziegler hardening rule of plasticity theory. Other relationships between lateral forces and stiffnesses are also included in the formulation. A change of yielding surface size is used to account for axial load variations.
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Oxidation and stabilisation chemistry of metallocene-based polyolefins during melt processing
… on the stabilisation of m-LLDPE melt. A Ziegler-polymerized LLDPE (z-LLDPE) based on the same comonomer was chosen and processed under the same conditions for comparison with the metallocene polymers. The LLDPE polymers were processed using an internal mixer (torque rheometer, TR) and a …
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Mechanisms of Pteridine-Ommochrome Interactions in Drosophila Melanogaster
… of a seemingly unrelated metabolic pathway (Ziegler 1961; Kaufman 1967a). Mutations which alter the synthesis of these pigments are manifested as numerous variations in eye color (Lindsley and Grell 1967). Suppressed production of brown pigment results in the accumulation of ommochrome …
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