Oxidation of oil/paper insulation initiates premature aging and introduces carboxylic acids with eventual increase in oil acidity, which hampers the properties of the oil. In this paper, a membrane separation technology-based purification process for aged insulation oil has been evaluated and reported. The intent of the present study is to eliminate carboxylic acids, dissolved decay contents and other colloidal contamination present in aged oil and enhance the useful life of oil. The potential of the membrane treatment process has been demonstrated using Ultraviolet Visible Infrared Spectroscopy and Fourier Transform Infrared Spectroscopy diagnostic measurements for oil and membrane. Additionally, membrane retention properties like membrane flux, retention coefficient, sorption time and membrane mass have been analyzed to understand the treatment process. To further evaluate the performance of the membrane and effectiveness of the treatment process, acidity, dielectric dissipation factor, relative permittivity, and resistivity measurements of the oil before and after filtration have been also reported. The proposed membrane purification method has been tested for Algerian utility in-service oil samples. It is inferred that, membrane filtration method is a simple and effective method for treatment of aged oils and aids in extending the remnant life of the oil. The procedure is economically attractive because of increasing prices for transformer liquids, cost effective and environmentally sounds.
18 August 2017 in Journal of Food Processing and Preservation
This study aims to investigate the impact of the incorporation of starch (modified and non-modified) on the texture of the processed cheese in order to appreciate a new recipe on one hand and to try to reduce fat content (FC) on the other. The modeling of the experimental results has been performed. An experimental design was used (the variable factors are the amount of starch and FC). The dry extract (DE) of cheese and parameters derived from the modeling of rheological results are the selected responses. The cheese with a concentration of modified starch that is greater than 2% has a high viscosity at rest, while the cheese with non-modified starch has a lower viscosity. When the FC exceeds 15%, the viscosity increases as the concentration of the starch exceeds 2%. Below this concentration, the FC effect is negligible except when the starch concentration is 1%, in this case the viscosity decreases. GRAPHICAL ABSTRACT
The inclusion of double-walled carbon nanotubes in carboxymethyl xanthan-based hydrogels was developed in order to improve both mechanical and drug release (diclofenac) properties of these nanocomposites for potential application in the biomedical field. The synthesis of carboxymethyl xanthan was carried out by an esterification reaction between xanthan gum and monochloroacetic acid, and the grafting was confirmed by FTIR analysis. The obtained carboxymethyl derivatives exhibited higher hydrophilicity degrees of substitution compared to the native xanthan gum. The nanocomposites prepared using either raw or modified xanthan gum were characterized in terms of physical properties, and we evidenced both an increase in viscoelasticity by one order of magnitude and an improved distribution of the nanotubes within the hydrogel matrix in the case of the carboxymethyl xanthan. The trapping efficiency of diclofenac was improved by the addition of the nanotubes, reaching up to 74 wt %. While the nanotubes also allowed a slower release of the molecule. An in-vitro study was carried out to ensure that the CNTs grafted onto the modified CMX were not released during the diffusion of the active ingredient.