A Method for Measuring the Self-Cementing Characteristics of Fly Ash Pastes

1987 ◽  
Vol 113 ◽  
Author(s):  
R. I. A. Malek ◽  
D. M. Roy
Keyword(s):  
Molecular Weight ◽  
Fly Ash ◽  
Liquid Chromatograph ◽  
Cement Pastes ◽  
Molecular Weights ◽  
Matching Process ◽  
Chromatographic Peaks ◽  
Liquid Chromatographic ◽  
Derivatives Of ◽  
Molecular Weight Fractions

SUMMARYThe development of an improved method of trimethylsilylation [1] made possible the assessment of different polysilicate fractions in hydrated cement pastes, as a means of structural characterization. Several laboratories have presented various gas-liquid chromatographic data on the polysilicate derivatives of C-S-H [2–5]. Identification of the different molecular weight fractions has been made, in most laboratories, by matching the gasliquid chromatographic peaks with the gel permeation chromatographic peaks. The success of this matching process is always dependent on type of instruments, length of columns and temperature range.In the present investigation, a mass spectrometer, in direct contact with the gas-liquid chromatograph, was used to identify the molecular weight of each of the fractions separated from the chromatograph. The technique was applied to determine the molecular weights and abundances of different polysilicate species in hydrated fly ash pastes.

scholarly journals α-Crystallin. The isolation and characterization of distinct macromolecular fractions

1971 ◽  
Vol 124 (2) ◽  
pp. 337-343 ◽  
Author(s):  
Abraham Spector ◽  
Lu-Ku Li ◽  
Robert C. Augusteyn ◽  
Arthur Schneider ◽  
Thomas Freund
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Gel Filtration ◽  
Deae Cellulose ◽  
Chemical Difference ◽  
Molecular Weights ◽  
Isolation And Characterization ◽  
Different Populations ◽  
Molecular Weight Fractions

α-Crystallin was isolated from calf lens periphery by chromatography on DEAE-cellulose and gel filtration. Three distinct populations of macromolecules have been isolated with molecular weights in the ranges approx. 6×105−9×105, 0.9×106−4×106and greater than 10×106. The concentration of macromolecules at the molecular-weight limits of a population are very low. The members of the different populations do not appear to be in equilibrium with each other. Further, in those molecular-weight fractions investigated, no equilibrium between members of the same population was observed. The population of lowest molecular weight comprises 65–75% of the total material. The amino acid and subunit composition of the different-sized fractions appear very similar, if not identical. The only chemical difference observed between the fractions is the presence of significant amounts of sugar in the higher-molecular-weight fractions. Subunit molecular weights of approx. 19.5×103and 22.5×103were observed for all α-crystallin fractions.

Isoprene and Rubber. Part 29. High Molecular Hydrorubbers

1932 ◽  
Vol 5 (2) ◽  
pp. 136-140
Author(s):  
H. Staudinger ◽  
W. Feisst
Keyword(s):  
Molecular Weight ◽  
Catalytic Reduction ◽  
Molecular Form ◽  
Average Molecular Weight ◽  
Molecular Size ◽  
Decomposition Products ◽  
Molecular Weights ◽  
Rubber Part ◽  
Derivatives Of ◽  
Suitable Process

Abstract The molecular concept in organic chemistry is based upon the fact that the molecules, whose existence is proved by vapor density determinations, enter into chemical reactions as the smallest particles. If now it is assumed that organic molecular colloids like rubber are dissolved in dilute solution in molecular form then it must be proved that in the chemical transposition of macromolecules as well no change in the size of the macromolecules occurs. In the case of hemicolloids, therefore for molecular colloids with an average molecular weight of 1000 to 10,000, this has been proved by the reduction of polyindenes, especially of polysterenes, to hydroproducts with the same average molecular weight, and also by the fact that cyclorubbers do not change their molecular weight upon autoöxidation. The molecular weights of hemi-colloidal hydrocarbons are therefore invariable. This is much more difficult to prove in the case of rubber, although there are many more ways in which unsaturated rubber can be transposed than the stable polysterenes, polyindenes, and poly cyclorubbers. In most of the reactions with rubber, as in its action with nitrosobenzene, oxidizing agents, hydrogen halides, and halogens, an extensive decomposition takes place as a result of the instability of the molecule, which is referred to in another work. Therefore derivatives of rubber are not formed, but derivatives of hemi-colloidal decomposition products. The catalytic reduction of rubber in the cold appears to be the most suitable process of making it react without changing its molecular size in order to prove that in a chemical transposition its molecular weight remains the same.

Organobismuth compounds. I. Studies on triphenylbismuth(V) derivatives, Ph3BiX2

1970 ◽  
Vol 48 (16) ◽  
pp. 2488-2493 ◽  
Author(s):  
R. G. Goel ◽  
H. S. Prasad
Keyword(s):  
Molecular Weight ◽  
Infrared Spectra ◽  
Molecular Species ◽  
Structural Features ◽  
Molecular Weights ◽  
Electrical Conductances ◽  
Conductance Data ◽  
Chemical Constitution ◽  
Derivatives Of ◽  
Coordinate Structures

Triphenylbismuth(V) acid derivatives of the type, Ph3BiX2, where X = halide, nitrate, cyanate, acetate, haloacetate, or cyanoacetate have been prepared. Infrared spectra (4000 to 200 cm−1 region), electrical conductances, and molecular weights of these compounds have been studied to elucidate their structural features and chemical constitution. The molecular weight and conductance data show that these compounds behave as molecular species in benzene or nitromethane. The infrared spectroscopic results also indicate non-ionic five-coordinate structures. Bi—X stretching frequencies have been assigned for the difluoride, dichloride, dinitrate, dicyanate, and diacetate. These frequencies occur in the region 410–240 cm−1.

Control of Alfin Rubber Molecular Weight

1965 ◽  
Vol 38 (1) ◽  
pp. 103-111 ◽  
Author(s):  
V. L. Hansley ◽  
H. Greenberg
Keyword(s):  
Molecular Weight ◽  
Pilot Plant ◽  
Continuous Processing ◽  
Molecular Weights ◽  
Solution Type ◽  
Pilot Plant Scale ◽  
Heat Build Up ◽  
Derivatives Of

Abstract Control of molecular weight of alfin catalyzed diene polymers has been demonstrated for polymers of butadiene, isoprene, styrene, piperylene and combinations of these. The 1,4-dihydro derivatives of benzene and naphthalene are effective molecular weight moderators. The known microstructure of alfin polymers remains unchanged with the use of these agents. Molecular weight controlled alfin gums process readily on standard rubber machinery. Oil extenders or softeners, although not necessary, are easily incorporated. The feasibility of continuous processing has been demonstrated for the production of catalyst, moderators and polymers on pilot plant scale. A wide series of polymers and copolymers at predetermined molecular weights and compositions have been produced in the same pilot plant. Alfin polybutadiene with limited amounts of styrene is essentially a solution type SBR. Alfin copolymers with styrene and/or isoprene have undergone preliminary road tests in tires. Wear and heat build-up data indicate performance to be intermediate between SBR and polybutadiene.

Effect of Primary Molecular Weight on the Dynamic Properties of Cured Rubber

1959 ◽  
Vol 32 (3) ◽  
pp. 651-661
Author(s):  
E. V. Kuvshinskiĭ ◽  
M. M. Fomicheva
Keyword(s):  
Molecular Weight ◽  
Dynamic Modulus ◽  
Room Temperature ◽  
Dynamic Properties ◽  
Molecular Weights ◽  
Vulcanized Rubber ◽  
Equilibrium Modulus ◽  
Modulus Of Resilience ◽  
Molecular Weight Fractions ◽  
Butadiene Styrene

Abstract 1. Studied were the moduli of resilience and rebound elasticity of the vulcanized rubbers made from fractions of butadiene-styrene rubber “SKS-30-A” at temperatures of 20, 60, and 100° C in the region of molecular weights from 45,000 to 620,000 with various degrees of vulcanization (with variation in the pseudoequilibrium modulus from 5 to 70 kg/cm2). 2. The dynamic modulus of resilience is little dependent on the molecular weight of the original rubber both at room temperature and at higher temperatures. 3. At higher temperatures the elasticity of vulcanized rubber is mainly determined by the degree of vulcanization, the measure of which is the pseudo-equilibrium modulus, and is little dependent on the initial molecular weight. At low temperatures (20° C) elasticity increases with the degree of vulcanization, but it increases at different rates for vulcanized rubbers made from fractions with different molecular weights. At 20° C the increase in the degree of vulcanization increases the elasticity of vulcanized rubbers made from low-molecular fractions (45,000) to a lower degree than of those made from high molecular weight fractions (above 133,000). 4. The value of the maximum elasticity of vulcanized rubbers obtained from rubbers of the same molecular weight is not dependent on the type of accelerator used.

Identification of High Molecular Weight Derivatives of Plasmic Digests of Cross-Linked Human Fibrin

1978 ◽  
Vol 40 (02) ◽  
pp. 368-376 ◽  
Author(s):  
E Regañon ◽  
V Vila ◽  
J Aznar
Keyword(s):  
Molecular Weight ◽  
Present Report ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Molecular Weights ◽  
Main Components ◽  
Derivatives Of ◽  
Β Chain ◽  
D Dimer ◽  
Different Molecular Weight

SummaryHighly cross-linked human fibrin was digested with plasmin and the nine main components (labelled initially 1 to 9) were detected by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The components of greater molecular weight, bands 1 and 2, which are identified with fragments Y dimer and Y-D (270,000 and 220,000) contain three subunits which are joined by disulphide bonds which originate from the α, β and γ-γ-chains of cross-linked fibrin. They show a reaction of partial identity against anti fibrinogen fragment D-sera and anti fibrinogen fragment E sera. Bands 3, 4 and 5 correspond to three species of fragment D-dimer and have molecular weights of 175,000,160,000 and 130,000. Each of these species differs in the size of the γ-γ-chain remnants, while all maintain the cross-link between the γ-γ-chains. The remnants of a and β-chains of cross-linked fibrin remain the same in all three species. The components of electrophoretic bands 6, 7 and 8 correspond to three fragments, each with a different molecular weight and with common antigenic components against anti fibrinogen fragment D-sera; these are called D6 (90,000), D7 (75,000) and D8 (65,000) and are formed by α- and β-chain remnants of equal molecular weight and by γ-chain remnants with a different molecular weight for each fragment. The last fragment to be identified, corresponding to electrophoretic band 9 (50,000 molecular weight) corresponds to fibrin fragment E. The present report is in agreement with previous studies of plasmin digestion of highly cross-linked fibrin, but differs from them in number of fragments D-dimer which appear during the digestion.

Electron-capture gas-liquid chromatographic determination of ethosuximide and desmethylmethsuximide in plasma or serum.

1979 ◽  
Vol 25 (2) ◽  
pp. 252-255 ◽  
Author(s):  
J E Wallace ◽  
H A Schwertner ◽  
H E Hamilton ◽  
E L Shimek
Keyword(s):  
Electron Capture ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Salting Out ◽  
Liquid Chromatograph ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Derivatives Of

Abstract We describe the determination of ethosuximide and desmethylmethsuximide, simultaneously or separately, in 50 to 100 microliter of plasma or serum. Derivatives of ethosuximide and desmethylmethsuximide formed by reaction with pentafluorobenzoyl chloride are extremely sensitive to the electron-capture detector of a gas-liquid chromatograph. The sample, with added internal standard and ammonium sulfate as a pH-adjusting and salting-out agent, is extracted with ethyl acetate/benzene (20/80 by vol). The extract is evaporated and the derivatives are formed. Analytical recoveries of ethosuximide and desmethylmethsuximide exceed 99%, and the relative standard deviation (CV) between analyses is usually less than 4.0%. alpha-Methyl-alpha-propylsuccinimide is used as the internal standard for ethosuximide, 2-phenylsuccinimide as the internal standard for desmethylmethsuximide.

scholarly journals POLYFUNCTIONAL DINITROPHENYL HAPTENS AS REAGENTS FOR ELICITATION OF IMMEDIATE TYPE ALLERGIC SKIN RESPONSES

1962 ◽  
Vol 115 (4) ◽  
pp. 789-801 ◽  
Author(s):  
Charles W. Parker ◽  
Milton Kern ◽  
Herman N. Eisen
Keyword(s):  
Molecular Weight ◽  
Guinea Pig ◽  
Antibody Formation ◽  
Antibody Affinity ◽  
Molecular Weights ◽  
Allergic Skin ◽  
Cutaneous Reactions ◽  
Skin Responses ◽  
Derivatives Of ◽  
Induce Antibody

Dinitrophenyl derivatives of differing molecular weights and degrees of substitution have been contrasted with respect to their ability to elicit immediate type allergic responses and their capacity to induce antibody formation in the guinea pig. In contradistinction to dinitrophenyl-proteins, bis-DNP-lysine and DNP-polylysines (including a 100,000 molecular weight derivative) failed to induce antibody detectable by guinea pig passive cutaneous anaphylaxis. Dinitrophenyl-polylysines evoked urticarial responses non-specifically, but after succinylation were about as effective as dinitrophenyl-proteins in eliciting specific cutaneous reactions. An important factor influencing the effectiveness of bis-DNP-lysine in evoking specific wheal-and-erythema responses is antibody affinity for the dinitrophenyl-lysyl determinant.

Schiff Base Derivatives of Lanthanons / Synthesis of La(III) Pr(III) and Nd(III) Derivatives of Ethylenediamine Bis-2,4-pentanedione

1975 ◽  
Vol 30 (1-2) ◽  
pp. 50-54 ◽  
Author(s):  
S. K. Agarwal ◽  
J. P. Tandon
Keyword(s):  
Molecular Weight ◽  
Schiff Base ◽  
Butyl Alcohol ◽  
Exchange Reactions ◽  
Molecular Weights ◽  
Tetradentate Schiff Base ◽  
Schiff Base Derivatives ◽  
Tert Butyl Alcohol ◽  
Derivatives Of

The 1:1 and 2:3 molar reactions of La(III), Pr(III) and Nd(III) isopropoxides with the bifunctional tetradentate Schiff base, ethylenediamine bis-2,4-pentanedione [AA2(CH2)2H2] have been investigated in the medium of dry benzene.Ln(O-i-C3H7) [AA2(CH2)2] and Ln2[AA2(CH2)2]3 [where, Ln = La(III), Pr(III) or Nd(III) and AA2(CH2)2- 2 anion of the corresponding Schiff base, AA2(CH2)2H2] type of compounds have been obtained in almost quantitative yields and in a state of sufficient purity. The 1:1 derivatives have been shown to undergo exchange reactions with an excess of tert-butyl alcohol leading to the formation of Ln(O-tert-C4H9) [AA2(CH2)2] [where, Ln = La(III), Pr(III) or Nd(III)] type of derivatives. The ebullioscopic determination of molecular weights shows that the 1:1 derivatives are dimeric, whereas 2:3 derivatives are monomeric in boiling benzene. On the basis of elemental analysis, exchange reactions, molecular weight determinations and IR spectra, plausible structures for the resulting 1:1 and 2:3 complexes have been indicated.

PHYSICOCHEMICAL STUDIES OF LIGNINSULPHONATES: II. BEHAVIOR AS POLYELECTROLYTES

1955 ◽  
Vol 33 (10) ◽  
pp. 1491-1501 ◽  
Author(s):  
J. L. Gardon ◽  
S. G. Mason
Keyword(s):  
Molecular Weight ◽  
Aqueous Solutions ◽  
High Molecular Weight ◽  
Intrinsic Viscosity ◽  
Micelle Formation ◽  
Low Molecular Weight ◽  
Molecular Weights ◽  
Physicochemical Studies ◽  
Molecular Weight Fractions ◽  
Molecular Branching

Conductivity, dyestuff adsorption, and viscosity measurements on aqueous solutions of fractionated ligninsulphonate samples having various molecular weights indicate that they behave as flexible polyelectrolytes. There is evidence that ligninsulphonates of molecular weight less than 5000 associate in solution in a manner analogous to micelle formation in colloidal electrolytes. From the variation of intrinsic viscosity with molecular weight, it may be concluded that the degree of molecular branching of the high molecular weight ligninsulphonates is greater than that of the low molecular weight fractions.

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