Anicuta Stoica

Potassium sorbate release from poly(vinyl alcohol)-bacterial cellulose films ‡

Active packaging materials are the subject of research because their performance exceeds that of traditional packaging. From this class, antimicrobial materials extend the shelf-life of products and reduce the risk of contamination by pathogens. In this paper, new composite materials with antimicrobial properties are obtained by using polyvinyl alcohol and bacterial cellulose powder. Potassium (2E,4E)-hexa-2,4-dienoate was used as the antimicrobial agent. The films thus obtained were characterised using Fourier-transform infrared spectroscopy and scanning electron microscopy. Mass transfer phenomena concerning the release of potassium (2E,4E)-hexa-2,4-dienoate were investigated. The results indicated that the new biocomposite films could be used as antimicrobial packaging materials.

Catalytic Effects at Pyrolysis of Wheat Grains Impregnated with Nickel Salts

Pyrolysis was performed on wheat grains untreated or impregnated with nickel nitrate solutions, into a fixed bed column, in the presence of a carbon dioxide stream. This produced a char with or without nickel, pyrolytic oil and a gaseous fraction. The distribution of these fractions was dependent on variations in heat flux, carbon dioxide superficial velocity and nickel nitrate solution concentration. The paper focused on establishing the qualitative and quantitative influence of these experimental variables on pyrolysis dynamics. In order to obtain a process characterization, a factorial experiment was used, wherein the pyrolysed material mass, collected oil mass, operating time, material bed temperature, volatiles temperature and column wall temperature were the evaluated process responses. A model reproducing pyrolysis curves was proposed considering the process dynamics as a result of competition between the appearance and extension of local pyrolysis points.

Modelling of water consumption in a spent fuel storage facility

In current practice, spent fuel is most commonly stored in a special basin of distilled or demineralised water for a required time period to reduce the amount of heat generated by radioactive decay to a level that can permit reprocessing. The processes taking place inside the spent fuel induce complex processes in the storage basin. The loss of water from the storage basin by means of simultaneous heat and mass transfer between water and the surrounding air is the case analysed in this paper by modelling. The developed model can be easily coupled with others, particularly models providing a consistent explanation of known situations (oxygen delivery from the basin, discharging of gases generated by processes from the fuel, increasing of the water activity, etc.). In this paper, some concrete references are related to the spent fuel storage facility at Magurele, Romania.