Theoretical analysis and experimental study of H2S dissociation processes in ultrahigh-frequency plasmotron

Theoretical analysis of aerodynamic conditions in a plasma chemical reactor with tangential gas supply is carried out. It is shown that due to the creation of a swirling flow in the reactor there is a pressure gradient, due to this along the vertical axis there is a vacuum zone, which contributes to the occurrence of plasma discharge. On the basis of the carried-out experimental researches of plasmolysis of hydrogen sulphide in a swirling stream and the analysis of images of the plasma discharge with use of monochromatic light filters the general structure of the plasma discharge is established. The influence of the temperature gradient in the reactor on the possibility of the formation of sulphur clusters as a prerequisite for the formation of a high molecular weight product – polymeric sulphur – was established.

Synthesis and Characterization of Acrylamide-Based Anionic Copolymer and Investigation of Solution Properties

The copolymer of acrylamide (AM) and 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS) was synthesized through radical solution polymerization by potassium persulfate as initiator. By changing the AMPS feed ratio from 10 to 70%, and keeping other reaction conditions constant, different copolymers were synthesized. The techniques of Fourier transform infrared (FTIR) and nuclear magnetic resonance (1H-13C-NMR) spectroscopy were used for identification of functional groups and confirmation of copolymers’ structure. Intrinsic and apparent viscosity of samples were measured in aqueous sodium chloride solution under standard conditions. The anionic degree of copolymers was determined by back titration method and by13C-NMR spectroscopy. Molecular weight of copolymers was determined by the Mark-Houwink relationship. The measured molecular weight of samples showed that we have acquired a high molecular weight product. The effect of different range of shear rates on solution viscosity was evaluated. The copolymer solutions showed non-Newtonian shear thinning behavior. The performance of copolymers with respect to shear resistance and molecular weight was evaluated from industry application standpoint.

Lignin-Carbohydrate Condensation Product Formation in a Biomimetic Model Pulp Bleaching System

Three biomimetic compounds were evaluated for their ability to preferentially degrade lignin in the presence of carbohydrate using two water-soluble polymeric model compounds: lignosulfonate and hydroxyethyl cellulose (HEC). The three biomimetic systems studied were FeSO4, Fe-EDTA and hemoglobin, each in the presence of hydrogen peroxide. When both polymeric substrates were present, a high molecular weight product was observed to form upon addition of H2O2. This high molecular weight product is believed to be the result of a condensation reaction between lignosulfonate and HEC. The condensation product was also observed to form in the absence of biomimetic catalyst. For all reactions, the molecular weight of the condensation product was observed to decrease with increasing reaction time. By altering the ratio of lignosulfonate to HEC, a limit was observed in the relative amount of condensation product formed. The formation of this condensation product is believed to limit the effectiveness of acidic bleaching systems.

Zinc Oxide Crosslinking Chemistry of Halobutyl Elastomers—A Model Compound Approach

The study of the crosslinking reactions of halobutyl rubbers with zinc oxide, conducted on low molecular weight model compounds, has brought about a thorough understanding of the chemistry of this process. It has been shown that there are two competitive processes taking place, with the major one generating the catalyst for the oligomerization reaction and producing a substantial amount of a monomeric diene. The actual crosslinking process is a cationically induced oligomerization based on carbon-carbon bond formation. The major high molecular weight product is the dimeric hydrocarbon with a small amount of trimeric product also being formed. Both the direct elimination reaction and the crosslinking process lead to the formation of dienic functional groups.

Uptake and Catabolism of 125l-Thrombin by the Rabbit Thoracic Aorta In Vitro: Permeability of the Endothelium, Intima-Media and Adventitial Layers

SummaryThe uptake, distribution and catabolism of 125I-thrombin has been studied in vitro using normal and ballooned (de-endothelialized) aorta segments at 37° C and at 4° C. In addition to rapid uptake by endothelial cells, 125I-thrombin passed at a slower, and yet constant, rate through the endothelium and accumulated in the intima-medial and adventitial layers. The enzyme, however, was not able to cross the adventitia. Passage through the endothelium was probably intercellular rather than due to transcytosis. Uptake by the intima-media layer of ballooned segments was substantially faster (× 2.5) than by the subendothelial (intima-media) region of normal segments. Once associated with the endothelium and the subendothelial layers, 125I-thrombin was catabolized and radioactive products, which were released from the vessel wall, appeared in the incubation medium. Two possible catabolic routes were identified: 1. the enzyme was recovered as a high molecular weight product (i. e. excluded by Sephadex G-200), due to complex formation with an extracellular vessel wall component and/or plasma antithrombin III. 2. Fragments of the enzyme were recovered which were presumably the products of limited, extracellular proteolysis.