Dielectric behavior of aqueous solutions of sodium polyphosphates of low degree of polymerization

1976 ◽  
Vol 14 (5) ◽  
pp. 773-781 ◽  
Author(s):  
W. M. Van Beek ◽  
T. J. Odijk ◽  
F. Van Der Touw ◽  
M. Mandel
Keyword(s):  
Aqueous Solutions ◽  
Dielectric Behavior ◽  
Degree Of Polymerization ◽  
Low Degree

scholarly journals Effect of TiO2 and ZnO Nanoparticles on the Performance of Dielectric Nanofluids Based on Vegetable Esters During Their Aging

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 692
Author(s):  
Inmaculada Fernández ◽  
Rafael Valiente ◽  
Félix Ortiz ◽  
Carlos J. Renedo ◽  
Alfredo Ortiz
Keyword(s):  
Breakdown Voltage ◽  
Vegetable Oil ◽  
Thermal Aging ◽  
Heat Dissipation ◽  
Dissipation Factor ◽  
Dielectric Behavior ◽  
Degree Of Polymerization ◽  
Point Of View ◽  
Transformer Oils ◽  
Natural Ester

Over the last few decades the insulating performance of transformer oils has been broadly studied under the point of view of nanotechnology, which tries to improve the insulating and heat dissipation performance of transformer oils by suspending nanoparticles. Many authors have analyzed the thermal and dielectric behavior of vegetable oil based-nanofluids, however, very few works have studied the evolution of these liquids during thermal aging and their stability. In this paper has been evaluated the performance of aged vegetable oil based-nanofluids, which have been subjected to accelerated thermal aging at 150 °C. Nanoparticles of TiO2 and ZnO have been dispersed in a commercial natural ester. Breakdown voltage, resistivity, dissipation factor and acidity of nanofluid samples have been measured according to standard methods, as well as stability. Moreover, it has been analyzed the degradation of Kraft paper through the degree of polymerization (DP). The results have showed that although nanoparticles improve breakdown voltage, they increase the ageing of insulation liquids and dielectric paper.

Clinical Evaluation of Class I Restorations Made with Composite with Low Degree of Polymerization Shrinkage

2016 ◽  
Vol 16 (9) ◽  
pp. 1-7 ◽  
Author(s):  
Carlos Gasparello ◽  
Carlos Nassar ◽  
Priscilla Busato ◽  
Márcio Mendonça ◽  
Lyvia Bertacchini ◽  
...  
Keyword(s):  
Clinical Evaluation ◽  
Degree Of Polymerization ◽  
Class I ◽  
Polymerization Shrinkage ◽  
Low Degree

COMPARISON OF BARLEY GUMS ISOLATED BY VARIOUS PROCEDURES

1953 ◽  
Vol 31 (7) ◽  
pp. 653-664 ◽  
Author(s):  
W. O. S. Meredith ◽  
T. A. Watts ◽  
J. A. Anderson
Keyword(s):  
Aqueous Solutions ◽  
Molecular Complex ◽  
Alkali Treatment ◽  
Molecular Size ◽  
Degree Of Polymerization ◽  
Aqueous Extraction ◽  
Water Soluble ◽  
Free Sugars ◽  
Enzyme Systems ◽  
Insoluble Form

A barley gum that is believed to be the undegraded, water-soluble, nonstarch polysaccharide of the grain has been isolated. Aqueous solutions of this gum are extremely viscous and are stable. Enzymes that degrade gum during simple aqueous extraction were inactivated first by refluxing barley grist in boiling 85% alcohol followed by extraction of the dried grist with a 1% solution of papain. Gums of lower degree of polymerization, as judged by viscosity measurements, were obtained by aqueous extraction and acid treatments. Two enzyme systems that degrade gums are thought to be present in barley. One (which is inactivated by alcohol) degrades the initially soluble gum and brings an initially insoluble form into solution. The second system (which is inactivated by papain) accompanies and degrades the initially soluble gum during aqueous extraction or in aqueous solutions of the preparation. The purest gum contains only 0.1% nitrogen, and this may be part of the molecular complex. Mild, cold, alkali treatment of this gum reduces molecular size considerably as measured by viscosity of solutions. "X"-enzyme isolated from a bacterial source cleaves the gum into two oligosaccharides of glucose and a component containing D-glucose, L-arabinose, D-xylose, and D-galactose. No free sugars are produced.

The cell-wall constituents of Apjohnia laetevirens Harvey

1969 ◽  
Vol 20 (2) ◽  
pp. 143 ◽  
Author(s):  
CM Stewart ◽  
CJ Dawes ◽  
BM Dickens ◽  
JWP Nicholls
Keyword(s):  
Cell Wall ◽  
Organic Solvent ◽  
Aqueous Solutions ◽  
Green Alga ◽  
Protein Complex ◽  
Cell Walls ◽  
Room Temperature ◽  
Organic Substances ◽  
Low Degree ◽  
Crystalline Aggregates

Cells of the green alga, Apjohnia laeterivens Harvey, have been ruptured in a Waring blendor in order to remove the majority of the protoplast from the cell-wall substances. The cell walls have been shown to contain, apart from extraneous protoplasmic constituents and some encrusting bryozoa, framework microfibrils of cellulose 1 which seem to be associated with pectin-like materials, arabinogalactan matrix substances and, perhaps, a polysaccharide-protein complex; these components appear to represent about 90% of the organic substances in the original organic-solvent extracted cell walls. Less than 25 % of the initial cellulose 1 was converted to cellulose 11 during treatments of several hours' duration at room temperature with aqueous solutions of 24% KOH and 17.5 % NaOH. The low degree of conversion is attributed to the presence of highly ordered and/or large "crystalline" aggregates of �-1,4'-glucan molecules in the cellulosic micelles of the framework microfibrils of the cell walls.

Mixed micelles of poly(styrene-b-3-(methacryloylamino)propyltrimethylammonium chloride-b-ethylene oxide) and anionic amphiphiles in aqueous solutions

2010 ◽  
Vol 88 (3) ◽  
pp. 208-216 ◽  
Author(s):  
Jingjing Liu ◽  
Airi Yoneda ◽  
Dian Liu ◽  
Yuuichi Yokoyama ◽  
Shin-ichi Yusa ◽  
...  
Keyword(s):  
Ethylene Oxide ◽  
Aqueous Solutions ◽  
Mixed Micelles ◽  
Organic Dyes ◽  
Sodium Dodecyl ◽  
Degree Of Polymerization ◽  
Hydrodynamic Diameter ◽  
Low Concentration ◽  
Fluorescence Measurements ◽  
Kinetics Of

The micelles of poly(styrene-b-3-(methacryloylamino)propyltrimethylammonium chloride-b-ethylene oxide) (PS-b-PMAPTAC-b-PEO) have been successfully prepared in aqueous solutions. The micelles have a PS core, cationic PMAPTAC shell, and PEO corona. Due to the short PS chain (degree of polymerization = 8), the formation of micelles is difficult at a low concentration, and the micelles are detected only at concentrations higher than 1 g L–1. The addition of anionic amphiphiles, such as sodium dodecyl sulfate (SDS) and poly(methacrylic acid) (PMAA), induces the formation of mixed micelles at a low concentration level of the polymer (~0.005 g L–1). This can be ascribed to insolubilization of the cationic PMAPTAC block due to charge neutralization by the anionic amphiphiles. The binding of SDS or PMAA to the PMAPTAC block is confirmed by zeta-potential measurements. The mixed micelles are characterized by dynamic light scattering (DLS), scanning electron microscopy (SEM), and fluorescence measurements. Based on DLS measurements, it is revealed that the hydrodynamic diameter of the mixed micelles falls in the range of 120–130 nm. SEM measurements provided clear pictures of mixed micelles with a spherical morphology. The kinetics of exchange of organic dyes between the micelle particles was investigated by fluorescence techniques. The result indicates that the exchange of the dyes between the micelle particles takes places within a time scale of seconds.

scholarly journals Human taste detection of glucose oligomers with low degree of polymerization

PLoS ONE ◽  
2017 ◽  
Vol 12 (8) ◽  
pp. e0183008 ◽  
Author(s):  
Alexa J. Pullicin ◽  
Michael H. Penner ◽  
Juyun Lim
Keyword(s):  
Degree Of Polymerization ◽  
Low Degree ◽  
Taste Detection

scholarly journals Molecular Growth Pathways in Silica Sol-Gel Polymerization

1988 ◽  
Vol 121 ◽  
Author(s):  
W. G. Klemperer ◽  
S. D. Ramamurthi
Keyword(s):  
Sol Gel ◽  
Molecular Size ◽  
Weight Fraction ◽  
Degree Of Polymerization ◽  
Partial Hydrolysis ◽  
Linear Polymers ◽  
Mole Percent ◽  
Molecular Weights ◽  
Low Degree ◽  
Acidic Conditions

ABSTRACTCapillary gas chromatography has been used to monitor the stoichi-ometries, structures, and abundances of low molecular weight polysilicate esters formed by partial hydrolysis of methanolic tetramethylorthosili-cate and redistribution of methanolie hexamethyoxydisiloxane under acidic (HC1) and basic (KOH) conditions. The polysilicate molecular size distributions, expressed in terms of mole percent of total silicon present as a function of degree of polymerization, show maxima near the number average degree of polymerization under acidic conditions. Under basic conditions, the distribution has its maximum at the monomer percent and extends to very high molecular weights, yielding a distribution far broader than the one observed under acidic conditions. These features are in agreement with covalent network theories of silica gelation, as opposed to particle aggregation theories. Weight fraction distributions of the type observed under acidic conditions are characteristic of linear polymers with a low degree of crosslinking and weight fraction distributions of the type observed under basic conditions are characteristic of branched polymers with high degree of crosslinking. The low degree of crosslinking obtained under acidic conditions is observed to arise from steric crowding that discourages branching in polysilicate structures.

scholarly journals Enzyme-Catalyzed Production of Potato Galactan-Oligosaccharides and Its Optimization by Response Surface Methodology

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1465 ◽  
Author(s):  
Mirian Angelene González-Ayón ◽  
Ángel Licea-Claveríe ◽  
José Benigno Valdez-Torres ◽  
Lorenzo A. Picos-Corrales ◽  
Rosabel Vélez-de la Rocha ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Degree Of Polymerization ◽  
Enzyme Substrate ◽  
Low Degree ◽  
Ft Ir ◽  
Cellvibrio Japonicus ◽  
Substrate Ratio ◽  
Optimized Conditions ◽  
Hydrolysis Of

This work shows an optimized enzymatic hydrolysis of high molecular weight potato galactan yielding pectic galactan-oligosaccharides (PGOs), where endo-β-1,4-galactanase (galactanase) from Cellvibrio japonicus and Clostridium thermocellum was used. For this, response surface methodology (RSM) by central composite design (CCD) was applied. The parameters varied were temperature (°C), pH, incubation time (min), and enzyme/substrate ratio (U/mg). The optimized conditions for the production of low degree of polymerization (DP) PGOs were obtained for each enzyme by spectrophotometric assay and confirmed by chromatography. The optimal conditions predicted for the use of C. japonicus galactanase to obtain PGOs of DP = 2 were T = 51.8 °C, pH 5, E/S = 0.508 U/mg, and t = 77.5 min. For DP = 3, they were T = 21 °C, pH 9, E/S = 0.484 U/mg, and t = 12.5 min; and for DP = 4, they were T = 21 °C, pH 5, E/S = 0.462 U/mg, and t = 12.5 min. The efficiency results were 51.3% for substrate hydrolysis. C. thermocellum galactanase had a lower yield (35.7%) and optimized conditions predicted for PGOs of DP = 2 were T = 60 °C, pH 5, E/S = 0.525 U/mg, and time = 148 min; DP = 3 were T = 59.7 °C, pH 5, E/S = 0.506 U/mg, and time = 12.5 min; and DP = 4, were T = 34.5 °C, pH 11, E/S = 0.525 U/mg, and time = 222.5 min. Fourier transformed infrared (FT-IR) and nuclear magnetic resonance (NMR) characterizations of PGOs are presented.

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