Interpretation of Microstructure of Poly-Isoprene and Polybutadiene Obtained in Anionic Polymerization

1967 ◽  
Vol 40 (3) ◽  
pp. 883-894 ◽  
Author(s):  
K. F. O'Driscoll ◽  
T. Yonezawa ◽  
T. Higashimura
Keyword(s):  
Experimental Data ◽  
Anionic Polymerization ◽  
Quantitative Model ◽  
Relative Reactivity ◽  
Mo Calculations ◽  
Model Based ◽  
Polymer Microstructures ◽  
Lcao Mo

Abstract A mechanism is proposed for the anionic homopolymerization of the diene monomers isoprene and butadiene. This mechanism qualitatively explains how the various polymer microstructures occur. A quantitative model based on this mechanism is treated by LCAO-MO calculations which include the effect of the counterion on the propagating chain. The results of the calculations are then compared with experimental data on microstructure and relative reactivity in hydrocarbon and tetrahydrofuran solvents. In every instance the comparisons give correct, semiquantitative agreement between calculation and experiment.

LCAO MO CALCULATIONS ON A SERIES OF NITRILES AND SOME RELATED MOLECULES BY A METHOD OF SELF-CONSISTENT FORMAL CHARGES

1964 ◽  
Vol 42 (6) ◽  
pp. 1323-1332 ◽  
Author(s):  
J. B. Moffat
Keyword(s):  
Experimental Data ◽  
Input Data ◽  
Electron Systems ◽  
Bond Orders ◽  
Mo Calculations ◽  
Bond Lengths ◽  
Triple Bonds ◽  
Self Consistent ◽  
Good Agreement ◽  
Lcao Mo

A method of self-consistent charges has been applied to an LCAO MO calculation of a series of nitriles and some related molecules. The π-electron bond orders and π-electron densities were calculated for all the molecules considered. The entire calculation was programmed for operation on the IBM 1620 with alterations of the input data for the different molecules. The calculated bond orders yield bond lengths for C—C and C=C bonds in good agreement with experimental data, except when two or more triple bonds are present in the molecule. By the assumption of additivity of the bond orders obtained for the two orthogonal pi-electron systems, bond orders are obtained which yield bond lengths in satisfactory agreement with the experimental results for all CC bonds. For the nitrile bonds the calculated bond orders were fitted to a linear equation with the experimental bond lengths.

Quantitative Model-Based Image Analysis of NuMa Distribution Links Nuclear Organization with Cell Phenotype

2001 ◽  
Vol 7 (S2) ◽  
pp. 578-579
Author(s):  
David W. Knowles ◽  
Sophie A. Lelièvre ◽  
Carlos Ortiz de Solόrzano ◽  
Stephen J. Lockett ◽  
Mina J. Bissell ◽  
...  
Keyword(s):  
Image Analysis ◽  
Mammary Epithelial Cells ◽  
Nuclear Organization ◽  
Critical Role ◽  
Quantitative Model ◽  
Mammary Epithelial ◽  
Cell Phenotype ◽  
Proliferating Cells ◽  
Mitotic Apparatus ◽  
Model Based

The extracellular matrix (ECM) plays a critical role in directing cell behaviour and morphogenesis by regulating gene expression and nuclear organization. Using non-malignant (S1) human mammary epithelial cells (HMECs), it was previously shown that ECM-induced morphogenesis is accompanied by the redistribution of nuclear mitotic apparatus (NuMA) protein from a diffuse pattern in proliferating cells, to a multi-focal pattern as HMECs growth arrested and completed morphogenesis . A process taking 10 to 14 days.To further investigate the link between NuMA distribution and the growth stage of HMECs, we have investigated the distribution of NuMA in non-malignant S1 cells and their malignant, T4, counter-part using a novel model-based image analysis technique. This technique, based on a multi-scale Gaussian blur analysis (Figure 1), quantifies the size of punctate features in an image. Cells were cultured in the presence and absence of a reconstituted basement membrane (rBM) and imaged in 3D using confocal microscopy, for fluorescently labeled monoclonal antibodies to NuMA (fαNuMA) and fluorescently labeled total DNA.

Mechanism of the propagation step in the anionic polymerization of styrene

1980 ◽  
Vol 45 (4) ◽  
pp. 1047-1055 ◽  
Author(s):  
Miroslav Kašpar ◽  
Jiří Trekoval
Keyword(s):  
Experimental Data ◽  
Induction Period ◽  
Anionic Polymerization ◽  
Reactive Intermediate ◽  
Coordination Polymerization ◽  
Kinetic Dependence ◽  
Mathematical Solution ◽  
Slow Reaction

The paper is dealing with an investigation of the kinetic dependence of the propagation step in the anionic coordination polymerization of styrene in benzene at 303 K with "living" oligostyryllithium as initiator at the onset of the reaction. A short but distinct induction period was found, indicating a preceding slow reaction leading to the formation of a reactive intermediate, which behaves as the initiator of the reaction. Using results obtained in the first paper of this series, a new mechanism of propagation has been suggested, the mathematical solution of which is correlated with experimental data.

Fuzzy Modeling to Simulate Surface Roughness in CNC Turning of AISI 1045 Steel

2011 ◽  
Vol 486 ◽  
pp. 262-265
Author(s):  
Amit Kohli ◽  
Mudit Sood ◽  
Anhad Singh Chawla
Keyword(s):  
Experimental Data ◽  
Surface Roughness ◽  
Process Parameters ◽  
Fuzzy Model ◽  
Fuzzy Modeling ◽  
Cnc Machine ◽  
Model Based ◽  
Aisi 1045 Steel ◽  
Aisi 1045 ◽  
1045 Steel

The objective of the present work is to simulate surface roughness in Computer Numerical Controlled (CNC) machine by Fuzzy Modeling of AISI 1045 Steel. To develop the fuzzy model; cutting depth, feed rate and speed are taken as input process parameters. The predicted results are compared with reliable set of experimental data for the validation of fuzzy model. Based upon reliable set of experimental data by Response Surface Methodology twenty fuzzy controlled rules using triangular membership function are constructed. By intelligent model based design and control of CNC process parameters, we can enhance the product quality, decrease the product cost and maintain the competitive position of steel.

SEMIEMPIRICAL SCF–LCAO–MO TREATMENT OF THIOPHENE, FURAN, AND PYRROLE

1965 ◽  
Vol 43 (5) ◽  
pp. 1569-1576 ◽  
Author(s):  
N. Solony ◽  
F. W. Birss ◽  
John B. Greenshields
Keyword(s):  
Experimental Data ◽  
Satisfactory Agreement ◽  
Electronic Structures ◽  
Spectroscopic Data ◽  
Variable Parameter ◽  
Coulomb Repulsion ◽  
Resonance Integral ◽  
Electronic Transitions ◽  
The Core ◽  
Lcao Mo

The semiempirical SCF–LCAO–MO method of Pariser–Parr–Pople is utilized in the study of the π-electronic structures of thiophene, furan, and pyrrole. The core Hamiltonian expansion contains a Uz++ term, the potential due to the ionized hetero-atom contributing two electrons to the π-system. The γzz, one-center coulomb repulsion integral for the hetero-atom is evaluated from the experimental spectroscopic data only. With the resonance integral βczc as the only variable parameter, the calculated π*–π electronic transitions are in a satisfactory agreement with the experimental data.

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