The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform
Andrew J. Coleman - One of the best experts on this subject based on the ideXlab platform.
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Raoult's law‐based method for determination of coal tar Average Molecular Weight
Environmental Toxicology and Chemistry, 2005Co-Authors: Derick G. Brown, Lovleen Gupta, Horace K. Moo-young, Andrew J. ColemanAbstract:A Raoult's law-based method for determining the number Average Molecular Weight of coal tars is presented. The method requires data from two-phase coal tar/water equilibrium experiments, which readily are performed in environmental laboratories. An advantage of this method for environmental samples is that it is not impacted by the small amount of inert debris often present in coal tar samples obtained from contaminated sites. Results are presented for 10 coal tars from nine former manufactured gas plants located in the eastern United States. Vapor pressure osmometry (VPO) analysis provided similar Average Molecular Weights to those determined with the Raoult's law-based method, except for one highly viscous coal tar sample. Use of the VPO-based Average Molecular Weight for this coal tar resulted in underprediction of the coal tar constituents' aqueous concentrations. Additionally, one other coal tar was not completely soluble in solvents used for VPO analysis. The results indicate that the Raoult's law-based method is able to provide an Average Molecular Weight that is consistent with the intended application of the data (e.g., modeling the dissolution of coal tar constituents into surrounding waters), and this method can be applied to coal tars that may be incompatible with other commonly used methods for determining Average Molecular Weight, such as vapor pressure osmometry.
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raoult s law based method for determination of coal tar Average Molecular Weight
Environmental Toxicology and Chemistry, 2005Co-Authors: Derick G. Brown, Lovleen Gupta, Horace K Mooyoung, Andrew J. ColemanAbstract:A Raoult's law-based method for determining the number Average Molecular Weight of coal tars is presented. The method requires data from two-phase coal tar/water equilibrium experiments, which readily are performed in environmental laboratories. An advantage of this method for environmental samples is that it is not impacted by the small amount of inert debris often present in coal tar samples obtained from contaminated sites. Results are presented for 10 coal tars from nine former manufactured gas plants located in the eastern United States. Vapor pressure osmometry (VPO) analysis provided similar Average Molecular Weights to those determined with the Raoult's law-based method, except for one highly viscous coal tar sample. Use of the VPO-based Average Molecular Weight for this coal tar resulted in underprediction of the coal tar constituents' aqueous concentrations. Additionally, one other coal tar was not completely soluble in solvents used for VPO analysis. The results indicate that the Raoult's law-based method is able to provide an Average Molecular Weight that is consistent with the intended application of the data (e.g., modeling the dissolution of coal tar constituents into surrounding waters), and this method can be applied to coal tars that may be incompatible with other commonly used methods for determining Average Molecular Weight, such as vapor pressure osmometry.
Regis Baron - One of the best experts on this subject based on the ideXlab platform.
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Decrease in dynamic viscosity and Average Molecular Weight of alginate from Laminaria digitata during alkaline extraction
Journal of Phycology, 2008Co-Authors: Peggy Vauchel, Abdellah Arhaliass, R. Kaas, Jack Legrand, Regis BaronAbstract:Alginates are natural polysaccharides that are extracted from brown seaweeds and widely used for their rheological properties. The central step in the extraction protocol used in the alginate industry is the alkaline extraction, which requires several hours. In this study, a significant decrease in alginate dynamic viscosity was observed after 2 h of alkaline treatment. Intrinsic viscosity and Average Molecular Weight of alginates from alkaline extractions 1–4 h in duration were determined, indicating depolymerization of alginates: Average Molecular Weight decreased significantly during the extraction, falling by a factor of 5 between 1 and 4 h of extraction. These results suggested that reducing extraction time could enable preserving the rheological properties of the extracted alginates.
Derick G. Brown - One of the best experts on this subject based on the ideXlab platform.
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Raoult's law‐based method for determination of coal tar Average Molecular Weight
Environmental Toxicology and Chemistry, 2005Co-Authors: Derick G. Brown, Lovleen Gupta, Horace K. Moo-young, Andrew J. ColemanAbstract:A Raoult's law-based method for determining the number Average Molecular Weight of coal tars is presented. The method requires data from two-phase coal tar/water equilibrium experiments, which readily are performed in environmental laboratories. An advantage of this method for environmental samples is that it is not impacted by the small amount of inert debris often present in coal tar samples obtained from contaminated sites. Results are presented for 10 coal tars from nine former manufactured gas plants located in the eastern United States. Vapor pressure osmometry (VPO) analysis provided similar Average Molecular Weights to those determined with the Raoult's law-based method, except for one highly viscous coal tar sample. Use of the VPO-based Average Molecular Weight for this coal tar resulted in underprediction of the coal tar constituents' aqueous concentrations. Additionally, one other coal tar was not completely soluble in solvents used for VPO analysis. The results indicate that the Raoult's law-based method is able to provide an Average Molecular Weight that is consistent with the intended application of the data (e.g., modeling the dissolution of coal tar constituents into surrounding waters), and this method can be applied to coal tars that may be incompatible with other commonly used methods for determining Average Molecular Weight, such as vapor pressure osmometry.
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raoult s law based method for determination of coal tar Average Molecular Weight
Environmental Toxicology and Chemistry, 2005Co-Authors: Derick G. Brown, Lovleen Gupta, Horace K Mooyoung, Andrew J. ColemanAbstract:A Raoult's law-based method for determining the number Average Molecular Weight of coal tars is presented. The method requires data from two-phase coal tar/water equilibrium experiments, which readily are performed in environmental laboratories. An advantage of this method for environmental samples is that it is not impacted by the small amount of inert debris often present in coal tar samples obtained from contaminated sites. Results are presented for 10 coal tars from nine former manufactured gas plants located in the eastern United States. Vapor pressure osmometry (VPO) analysis provided similar Average Molecular Weights to those determined with the Raoult's law-based method, except for one highly viscous coal tar sample. Use of the VPO-based Average Molecular Weight for this coal tar resulted in underprediction of the coal tar constituents' aqueous concentrations. Additionally, one other coal tar was not completely soluble in solvents used for VPO analysis. The results indicate that the Raoult's law-based method is able to provide an Average Molecular Weight that is consistent with the intended application of the data (e.g., modeling the dissolution of coal tar constituents into surrounding waters), and this method can be applied to coal tars that may be incompatible with other commonly used methods for determining Average Molecular Weight, such as vapor pressure osmometry.
Jose Carlos Pinto - One of the best experts on this subject based on the ideXlab platform.
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in line monitoring and control of conversion and Weight Average Molecular Weight of polyurethanes in solution step growth polymerization based on near infrared spectroscopy and torquemetry
Macromolecular Materials and Engineering, 2005Co-Authors: Evandro S Nogueira, Cristiano Piacsek Borges, Jose Carlos PintoAbstract:It is well known that the Weight-Average Molecular Weight (M w ) is strictly dependent on conversion in step-growth polymerizations performed in batch and that the M w is very sensitive to impurities and molar imbalance. This makes the work of controlling M w a non trivial job. In this paper a new methodology is introduced for in-line monitoring and control of conversion and M w of polyurethanes produced in solution step-growth polymerizations, based on near-infrared spectroscopy (NIRS) and torquemetry. A calibration model based on the PLS method is obtained and validated for monomer conversion, while the Weight-Average Molecular Weight is monitored indirectly with the relative shear signal provided by the agitator. Control procedures are then proposed and implemented experimentally to avoid gelation and allow for maximization of M w . The proposed monitoring and control procedures can also be applied to other step growth polymerizations.
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in line monitoring of Weight Average Molecular Weight in solution polymerizations using intrinsic viscosity measurements
Polymer, 2001Co-Authors: M P Vega, E L Lima, Jose Carlos PintoAbstract:Abstract The main objective of this work is developing a simple viscometrical method for in-line monitoring and control of Weight Average Molecular Weight ( M w ) in solution polymerizations. The method is based on the evaluation of the approximate intrinsic viscosity of the polymer solution, at each sampling time, using a single measurement of the flow time of a diluted polymer solution through a capillary tube. Experiments were carried out for peroxide initiated styrene solution polymerization reactions in a tubular reactor. Results obtained for approximate intrinsic viscosities are in agreement with the intrinsic viscosity values published in the literature and allow fast and fair in-line values for M w .
Lovleen Gupta - One of the best experts on this subject based on the ideXlab platform.
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Raoult's law‐based method for determination of coal tar Average Molecular Weight
Environmental Toxicology and Chemistry, 2005Co-Authors: Derick G. Brown, Lovleen Gupta, Horace K. Moo-young, Andrew J. ColemanAbstract:A Raoult's law-based method for determining the number Average Molecular Weight of coal tars is presented. The method requires data from two-phase coal tar/water equilibrium experiments, which readily are performed in environmental laboratories. An advantage of this method for environmental samples is that it is not impacted by the small amount of inert debris often present in coal tar samples obtained from contaminated sites. Results are presented for 10 coal tars from nine former manufactured gas plants located in the eastern United States. Vapor pressure osmometry (VPO) analysis provided similar Average Molecular Weights to those determined with the Raoult's law-based method, except for one highly viscous coal tar sample. Use of the VPO-based Average Molecular Weight for this coal tar resulted in underprediction of the coal tar constituents' aqueous concentrations. Additionally, one other coal tar was not completely soluble in solvents used for VPO analysis. The results indicate that the Raoult's law-based method is able to provide an Average Molecular Weight that is consistent with the intended application of the data (e.g., modeling the dissolution of coal tar constituents into surrounding waters), and this method can be applied to coal tars that may be incompatible with other commonly used methods for determining Average Molecular Weight, such as vapor pressure osmometry.
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raoult s law based method for determination of coal tar Average Molecular Weight
Environmental Toxicology and Chemistry, 2005Co-Authors: Derick G. Brown, Lovleen Gupta, Horace K Mooyoung, Andrew J. ColemanAbstract:A Raoult's law-based method for determining the number Average Molecular Weight of coal tars is presented. The method requires data from two-phase coal tar/water equilibrium experiments, which readily are performed in environmental laboratories. An advantage of this method for environmental samples is that it is not impacted by the small amount of inert debris often present in coal tar samples obtained from contaminated sites. Results are presented for 10 coal tars from nine former manufactured gas plants located in the eastern United States. Vapor pressure osmometry (VPO) analysis provided similar Average Molecular Weights to those determined with the Raoult's law-based method, except for one highly viscous coal tar sample. Use of the VPO-based Average Molecular Weight for this coal tar resulted in underprediction of the coal tar constituents' aqueous concentrations. Additionally, one other coal tar was not completely soluble in solvents used for VPO analysis. The results indicate that the Raoult's law-based method is able to provide an Average Molecular Weight that is consistent with the intended application of the data (e.g., modeling the dissolution of coal tar constituents into surrounding waters), and this method can be applied to coal tars that may be incompatible with other commonly used methods for determining Average Molecular Weight, such as vapor pressure osmometry.
