Modeling the Dynamics of the Xylene Soluble Fraction (XS) in a Bulk Propylene Polymerization Process

2010 ◽  
Vol 5 (2) ◽  
pp. 129-139 ◽  
Author(s):  
Fabricio Machado ◽  
José Carlos Pinto
Keyword(s):  
Soluble Fraction ◽  
Propylene Polymerization ◽  
Polymerization Process

Optimal Descriptor Based QSPR Models for Catalytic Activity of Propylene Polymerization

2018 ◽  
Vol 3 (2) ◽  
pp. 36-48
Author(s):  
Sanija Begum ◽  
P. Ganga Raju Achary
Keyword(s):  
External Validation ◽  
Propylene Polymerization ◽  
Polymerization Process ◽  
Input Line ◽  
Qspr Model ◽  
Monte Carlo Optimization ◽  
Catalytic Activities ◽  
Optimal Descriptor ◽  
Validation Set

A heterogeneous Ziegler–Natta (ZN) catalyst is an important catalyst in the field of the polypropylene polymerization industry. The role of electron donors has been crucial in the ZN catalyzed polypropylene polymerization process. In this article, quasi-SMILES-based QSPR models are elaborated for the prediction of catalytic activities. The representations of the molecular structure by quasi-simplified molecular input line entry system were the basis to build the desired QSPR model. These models were developed by means of the Monte Carlo optimization involving the available methods classic scheme (CS), balance of correlations (BC) and balance of correlation with ideal slopes (BCIS). The best QSPR model showed r2 = 0.813 (for external validation set), rm2 (avg)=0.73 and ∆rm2= 0.03.

5629254 Substituted indenyl ring containing metallocene catalyst for propylene polymerization process

1997 ◽  
Vol 125 (2-3) ◽  
pp. 174
Author(s):  
Daisuke Fukuoka ◽  
Takashi Tashiro ◽  
Koji Kawaai ◽  
Junji Saito ◽  
Takashi Ueda ◽  
...  
Keyword(s):  
Metallocene Catalyst ◽  
Propylene Polymerization ◽  
Polymerization Process

scholarly journals Soft Sensor Development Based on Quality-Relevant Slow Feature Analysis and Bayesian Regression with Application to Propylene Polymerization

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Miao Zhang ◽  
Le Zhou ◽  
Jing Jie ◽  
Xiaoli Wu
Keyword(s):  
Soft Sensor ◽  
Bayesian Regression ◽  
Propylene Polymerization ◽  
Polymerization Process ◽  
Feature Analysis ◽  
Quality Indices ◽  
Soft Sensors ◽  
Slow Feature Analysis ◽  
Iterative Maximum Likelihood

Data-driven soft sensors are widely used to predict quality indices in propylene polymerization processes to improve the availability of measurements and efficiency. To deal with the nonlinearity and dynamics in propylene polymerization processes, a novel soft sensor based on quality-relevant slow feature analysis and Bayesian regression is proposed in this paper. The proposed method can handle the dynamics of the process better by extracting quality-relevant slow features, which present both the slowly varying characteristic and the correlations with quality indices. Meanwhile, a Bayesian inference model is developed to predict the quality indices, which takes advantages of a probability framework with iterative maximum likelihood techniques for parameter estimation and a sparse constraint for avoiding overfitting. Finally, a case study is conducted with data sampled from a practical industrial propylene polymerization process to demonstrate the effectiveness and superiority of the proposed method.

The Effect of Benzene on Bluegill Olfactory Lamellae

1985 ◽  
Vol 43 ◽  
pp. 574-575
Author(s):  
D.R. Mattie ◽  
J.W. Fisher
Keyword(s):  
Surface Morphology ◽  
Soluble Fraction ◽  
Lepomis Macrochirus ◽  
Sublethal Concentration ◽  
Water Soluble ◽  
Major Constituent ◽  
Jet Fuels ◽  
Aquatic Biota ◽  
Normal Surface ◽  
Cacodylate Buffer

Jet fuels such as JP-4 can be introduced into the environment and come in contact with aquatic biota in several ways. Studies in this laboratory have demonstrated JP-4 toxicity to fish. Benzene is the major constituent of the water soluble fraction of JP-4. The normal surface morphology of bluegill olfactory lamellae was examined in conjunction with electrophysiology experiments. There was no information regarding the ultrastructural and physiological responses of the olfactory epithelium of bluegills to acute benzene exposure.The purpose of this investigation was to determine the effects of benzene on the surface morphology of the nasal rosettes of the bluegill sunfish (Lepomis macrochirus). Bluegills were exposed to a sublethal concentration of 7.7±0.2ppm (+S.E.M.) benzene for five, ten or fourteen days. Nasal rosettes were fixed in 2.5% glutaraldehyde and 2.0% paraformaldehyde in 0.1M cacodylate buffer (pH 7.4) containing 1.25mM calcium chloride. Specimens were processed for scanning electron microscopy.

The Effects of Amines on the Esterase Activities of Thrombin and Thrombokinase and on Several Clotting Tests

1974 ◽  
Vol 31 (02) ◽  
pp. 309-318
Author(s):  
Phyllis S Roberts ◽  
Raphael M Ottenbrite ◽  
Patricia B Fleming ◽  
James Wigand
Keyword(s):  
Choline Chloride ◽  
Polymerization Process ◽  
Ammonium Bromide ◽  
Bovine Thrombin ◽  
One Stage ◽  
Human Proteins ◽  
Rate Of Hydrolysis ◽  
The One ◽  
Hydrolysis Of Esters ◽  
Hydrolysis Of

Summary1. Choline chloride, 0.1 M (in 0.25 M Tris. HCl buffer, pH 7.4 or 8.0, 37°), doubles the rate of hydrolysis of TAME by bovine thrombokinase but has no effect on the hydrolysis of this ester by either human or bovine thrombin. Only when 1.0 M or more choline chloride is present is the hydrolysis of BAME by thrombokinase or thrombin weakly inhibited. Evidence is presented that shows that these effects are due to the quaternary amine group.2. Tetramethyl ammonium bromide or chloride has about the same effects on the hydrolysis of esters by these enzymes as does choline chloride but tetra-ethyl, -n.propyl and -n.butyl ammonium bromides (0.1 M) are stronger accelerators of the thrombokinase-TAME reaction and they also accelerate, but to a lesser degree, the thrombin-TAME reaction. In addition, they inhibit the hydrolysis of BAME by both enzymes. Their effects on these reactions, however, do not follow any regular order. The tetraethyl compound is the strongest accelerator of the thrombokinase-TAME reaction but the tetra-ethyl and -butyl compounds are the strongest accelerators of the thrombin-TAME reaction. The ethyl and propyl compounds are the best (although weak) inhibitors of the thrombokinase-BAME and the propyl compound of the thrombin-BAME reactions.3. Tetra-methyl, -ethyl, -n.propyl and -n.butyl ammonium bromides (0.01 M) inhibit the clotting of fibrinogen by thrombin (bovine and human proteins) at pH 7.4, imidazole or pH 6.1, phosphate buffers and they also inhibit, but to a lesser degree, a modified one-stage prothrombin test. In all cases the inhibition increases regularly as the size of the alkyl group increases from methyl to butyl. Only the ethyl com pound (0.025 M but not 0.01 M), however, significantly inhibits the polymerization of bovine fibrin monomers. It was concluded that inhibition of the fibrinogen-thrombin and the one-stage tests by the quaternary amines is not due to any effect of the com pounds on the polymerization process but probably due to inhibition of thrombin’s action on fibrinogen by the quaternary amines.

Plasminogen Activator and Plasminogen Activator Inhibitor Associated with Granulomatous Inflammation: A Study with Murine Leprosy

1984 ◽  
Vol 52 (03) ◽  
pp. 243-249 ◽  
Author(s):  
S Izaki ◽  
T Hibino ◽  
Y Isozaki ◽  
P S Hsu ◽  
M Izaki ◽  
...  
Keyword(s):  
Plasminogen Activator ◽  
Soluble Fraction ◽  
Proteinase Inhibitors ◽  
Granulomatous Inflammation ◽  
Serine Proteinase ◽  
Plasminogen Activator Inhibitor ◽  
Tissue Type ◽  
Weakly Alkaline ◽  
Heat Stable ◽  
Type Plasminogen Activator

SummaryPlasminogen activator that is associated with the development of hypersensitivity granulomas (gPA) was partially purified from a saline soluble fraction of murine lepromas elicited in “resistant” mice, C57BL/6N. The gPA was shown to consist of two subspecies (23,000 and 48,000 in molecular weight) with essentially identical enzymologic properties. The gPA was found to be a relatively heat stable weakly alkaline serine proteinase with trypsin-like characteristics in the specificity for synthetic substrates and proteinase inhibitors. It showed a high affinity for H- D-Ile-Pro-Arg-pNA (Km = 1.4 × 10-4 M) H-D-Val-Leu-Lys- pNA (Km = 5.2 × 10-4 M), and L-pyroGlu-Gly-Arg-pNA (Km = 9.3 × 10-4 M). The gPA did not demonstrate antigenic cross reaction with urokinase-type or tissue-type plasminogen activator.Two distinct enzymatic regulators of the gPA were also demonstrated in the saline soluble fraction of the hypersensitivity granulomas. The gPA and its regulation are assumed to be correlated with macrophage activation in the hypersensitivity granulomas

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