Improved characterization of anaerobic digestion kinetics of mixed sludges with and without thermally pretreated WAS.

Fuel particles for the High-Temperature Gas-Cooled Reactor (HTGR) contain a layer of pyrolytic silicon carbide to act as a miniature pressure vessel and primary fission product barrier. Optimization of the SiC with respect to fuel performance involves four areas of study: (a) characterization of as-deposited SiC coatings; (b) thermodynamics and kinetics of chemical reactions between SiC and fission products; (c) irradiation behavior of SiC in the absence of fission products; and (d) combined effects of irradiation and fission products. This paper reports the behavior of SiC deposited on inert microspheres and irradiated to fast neutron fluences typical of HTGR fuel at end-of-life.

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Kinetics of Batch Anaerobic Digestion of Vegetable Oil Wastewater

Open Journal of Water Pollution and Treatment ◽

10.15764/wpt.2014.02001 ◽

2014 ◽

Vol 2014 (2) ◽

pp. 1-10 ◽

Cited By ~ 3

Author(s):

Chinenyenwa Nweke ◽

◽

Philomena Igbokwe ◽

Joseph Nwabanne ◽

◽

...

Keyword(s):

Anaerobic Digestion ◽

Vegetable Oil ◽

Kinetics Of ◽

Oil Wastewater

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Digestion Kinetics of Parenchyma and Sclerenchyma Cell Walls Isolated from Orchardgrass and Switchgrass

Crop Science ◽

10.2135/cropsci1992.0011183x003200030046x ◽

1992 ◽

Vol 32 (3) ◽

pp. 806-810 ◽

Cited By ~ 34

Author(s):

John H. Grabber ◽

Gerald A. Jung ◽

Stephen M. Abrams ◽

Diantha B. Howard

Keyword(s):

Cell Walls ◽

Digestion Kinetics ◽

Kinetics Of

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Elaboration and Characterization of the Properties of Refractory Cr Base Alloys

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.72.46 ◽

2010 ◽

Vol 72 ◽

pp. 46-52 ◽

Cited By ~ 1

Author(s):

Laurent Royer ◽

Stéphane Mathieu ◽

Christophe Liebaut ◽

Pierre Steinmetz

Keyword(s):

Mechanical Properties ◽

Melting Point ◽

Molten Glass ◽

Energy Production ◽

Creep Properties ◽

Refractory Alloys ◽

Industrial Use ◽

Kinetics Of ◽

Selection Of

For energy production and also for the glass industry, finding new refractory alloys which could permit to increase the process temperatures to 1200°C or more is a permanent challenge. Chromium base alloys can be good candidates, considering the melting point of Cr itself, and also its low corrosion rate in molten glass. Two families of alloys have been studied for this purpose, Cr-Mo-W and Cr-Ta-X alloys (X= Mo, Si..). A finer selection of compositions has been done, to optimize their chemical and mechanical properties. Kinetics of HT oxidation by air, of corrosion by molten glass and also creep properties of several alloys have been measured up to 1250°C. The results obtained with the best alloys (Cr-Ta base) give positive indications as regards the possibility of their industrial use.

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New Trimethoprim-Like Molecules: Bacteriological Evaluation and Insights into Their Action

Antibiotics ◽

10.3390/antibiotics10060709 ◽

2021 ◽

Vol 10 (6) ◽

pp. 709

Author(s):

Marta Jorba ◽

Marina Pedrola ◽

Ouldouz Ghashghaei ◽

Rocío Herráez ◽

Lluis Campos-Vicens ◽

...

Keyword(s):

Inhibitory Concentration ◽

Efflux Pump ◽

Synergistic Effects ◽

Nicotinamide Adenine Dinucleotide Phosphate ◽

Detailed Characterization ◽

Low Concentrations ◽

Pump Activity ◽

Bacteriological Evaluation ◽

Kinetics Of

This work reports a detailed characterization of the antimicrobial profile of two trimethoprim-like molecules (compounds 1a and 1b) identified in previous studies. Both molecules displayed remarkable antimicrobial activity, particularly when combined with sulfamethoxazole. In disk diffusion assays on Petri dishes, compounds 1a and 1b showed synergistic effects with colistin. Specifically, in combinations with low concentrations of colistin, very large increases in the activities of compounds 1a and 1b were determined, as demonstrated by alterations in the kinetics of bacterial growth despite only slight changes in the fractional inhibitory concentration index. The effect of colistin may be to increase the rate of antibiotic entry while reducing efflux pump activity. Compounds 1a and 1b were susceptible to extrusion by efflux pumps, whereas the inhibitor phenylalanine arginyl β-naphthylamide (PAβN) exerted effects similar to those of colistin. The interactions between the target enzyme (dihydrofolate reductase), the coenzyme nicotinamide adenine dinucleotide phosphate (NADPH), and the studied molecules were explored using enzymology tools and computational chemistry. A model based on docking results is reported.

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Simultaneous Kinetics of Selenite Oxidation and Sorption on δ-MnO2 in Stirred-Flow Reactors

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18062902 ◽

2021 ◽

Vol 18 (6) ◽

pp. 2902

Author(s):

Zheyong Li ◽

Yajun Yuan ◽

Lin Ma ◽

Yihui Zhang ◽

Hongwei Jiang ◽

...

Keyword(s):

Rate Constant ◽

Photoelectron Spectroscopy ◽

Oxide Surfaces ◽

Kinetic Rate Constant ◽

Flow Reactors ◽

Mn Oxide ◽

Remediation Strategies ◽

Process Of Se ◽

Kinetics Of

Selenium (Se) is an essential and crucial micronutrient for humans and animals, but excessive Se brings negativity and toxicity. The adsorption and oxidation of Se(IV) on Mn-oxide surfaces are important processes for understanding the geochemical fate of Se and developing engineered remediation strategies. In this study, the characterization of simultaneous adsorption, oxidation, and desorption of Se(IV) on δ-MnO2 mineral was carried out using stirred-flow reactors. About 9.5% to 25.3% of Se(IV) was oxidized to Se(VI) in the stirred-flow system in a continuous and slow process, with the kinetic rate constant k of 0.032 h−1, which was significantly higher than the apparent rate constant of 0.0014 h−1 obtained by the quasi-level kinetic fit of the batch method. The oxidation reaction was driven by proton concentration, and its rate also depended on the Se(IV) influent concentration, flow rate, and δ-MnO2 dosage. During the reaction of Se(IV) and δ-MnO2, Mn(II) was produced and adsorbed strongly on Mn oxide surfaces, which was evidenced by the total reflectance Fourier transform infrared (ATR-FTIR) results. The X-ray photoelectron spectroscopy (XPS) data indicated that the reaction of Se(VI) on δ-MnO2 produced Mn(III) as the main product. These results contribute to a deeper understanding of the interface chemical process of Se(IV) with δ-MnO2 in the environment.

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Synthesis and Polymerization Kinetics of Rigid Tricyanate Ester

Polymers ◽

10.3390/polym13111686 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1686

Author(s):

Andrey Galukhin ◽

Roman Nosov ◽

Ilya Nikolaev ◽

Elena Melnikova ◽

Daut Islamov ◽

...

Keyword(s):

Kinetic Analysis ◽

Single Step ◽

Polymerization Kinetics ◽

Scanning Calorimetry ◽

Modulated Differential Scanning Calorimetry ◽

Diffusion Controlled ◽

Polymerization Product ◽

The One ◽

Kinetics Of

A new rigid tricyanate ester consisting of seven conjugated aromatic units is synthesized, and its structure is confirmed by X-ray analysis. This ester undergoes thermally stimulated polymerization in a liquid state. Conventional and temperature-modulated differential scanning calorimetry techniques are employed to study the polymerization kinetics. A transition of polymerization from a kinetic- to a diffusion-controlled regime is detected. Kinetic analysis is performed by combining isoconversional and model-based computations. It demonstrates that polymerization in the kinetically controlled regime of the present monomer can be described as a quasi-single-step, auto-catalytic, process. The diffusion contribution is parameterized by the Fournier model. Kinetic analysis is complemented by characterization of thermal properties of the corresponding polymerization product by means of thermogravimetric and thermomechanical analyses. Overall, the obtained experimental results are consistent with our hypothesis about the relation between the rigidity and functionality of the cyanate ester monomer, on the one hand, and its reactivity and glass transition temperature of the corresponding polymer, on the other hand.

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Biosorption and Diffusion Modeling of Pb(II) by Malt Bagasse

International Journal of Chemical Engineering ◽

10.1155/2016/4210561 ◽

2016 ◽

Vol 2016 ◽

pp. 1-11 ◽

Cited By ~ 4

Author(s):

Klaiani B. Fontana ◽

Giane Gonçalves Lenzi ◽

Erica R. L. R. Watanabe ◽

Ervin Kaminski Lenzi ◽

Juliana A. M. T. Pietrobelli ◽

...

Keyword(s):

Sorption Process ◽

Isotherm Models ◽

Diffusion Modeling ◽

Biosorption Capacity ◽

Kinetic And Thermodynamic Parameters ◽

Pseudo Second Order ◽

Ph Optimization ◽

Kinetics Of ◽

And Diffusion

The removal of Pb(II) from water by biosorption processes onto malt bagasse was investigated and the kinetic and thermodynamic parameters were obtained; additionally a diffusion modeling was proposed. The characterization of malt bagasse was performed by FTIR and SEM/EDS. The experiments were conducted in batch system and an experimental design based response surface methodology was applied for agitation speed and pH optimization. The kinetics of biosorption followed pseudo-second-order model and the temperature of the process affected the biosorption capacity. Isotherm models of Langmuir, Freundlich, and Elovich were applied and the Langmuir model showed better fit and the estimated biosorption capacity was 29.1 mg g−1. The negative values obtained for ΔG° and positive values of ΔH° confirm, respectively, the spontaneous and endothermic nature of the process. The diffusion modeling was performed based on experiments in the absence of agitation to investigate the influence of the biosorbent on the sorption process of Pb(II) ions.

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