93 resultados para performances
Resumo:
The performances of four LC-MS/MS methodologies for determination of up to eight mycotoxin biomarkers in human urines were compared by involving three laboratories that analysed common urine samples spiked at two levels of each biomarker. Each laboratory received a calibration solution, spiked urines and the corresponding unspiked urine. The two spiking levels for each biomarker were chosen by considering the levels naturally occurring in human urines and the limits of quantification of the LC-MS/MS methodologies used by the participating laboratories. The results of each laboratory were evaluated for their z-score values. The percentage of satisfactory z-scores (vertical bar z vertical bar 2) were obtained for fumonisin B-1 (7/12 results), ochratoxin A (4/8 results) and alpha-zearalenol (1/8 results). The percentage of satisfactory z-scores for fumonisin B-1 and ochratoxin A increased from 42 to 83% for fumonisin B-1 and from 50 to 62% for ochratoxin A when laboratories 1 and 2 used own calibrants. Factors that could explain the different results obtained for fumonisin B-1 and ochratoxin A with provided and own calibration solutions could not be identified in this study and should be carefully investigated in future studies.
Resumo:
Herein, we present the formulation and the characterization of novel adiponitrile-based electrolytes as a function of the salt structure, concentration, and temperature for supercapacitor applications using activated carbon based electrode material. To drive this study two salts were selected, namely, the tetraethylammonium tetrafluoroborate and the 1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide. Prior to determination of their electrochemical performance, formulated electrolytes were first characterized to quantify their thermal, volumetric, and transport properties as a function of temperature and composition. Then, cyclic voltammetry and electrochemical impedance spectroscopy techniques were used to investigate their electrochemical properties as electrolyte for supercapacitor applications in comparison with those reported for the currently used model electrolyte based on the dissolution of 1 mol·dm–3 of tetraethylammonium tetrafluoroborate in acetonitrile. Surprisingly, excellent electrochemical performances were observed by testing adiponitrile-based electrolytes, especially those containing the 1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide room-temperature molten salt. Differences observed on electrochemical performances between the selected adiponitrile electrolytes based on high-temperature (tetraethylammonium tetrafluoroborate) and the room-temperature (1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide) molten salts are mainly driven by the salt solubility in adiponitrile, as well as by the charge and the structure of each involved species. Furthermore, in comparison with classical electrolytes, the selected adiponitrile +1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide solution exhibits almost similar specific capacitances and lower equivalent serial resistance. These results demonstrate in fact that the adiponitrile +1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide mixture can be used for the formulation of safer electrolytes presenting a very low vapor pressure even at high temperatures to design acetonitrile-free supercapacitor devices with comparable performances.
Resumo:
Small mixer impeller design is not tailored for granulation because impellers are intended for a wide range of processes. The aim of this research was to evaluate the performances of several impellers to provide guidance on the selection and design for the purposes of granulation. Lactose granules were produced using wet granulation with water as a binder. A Kenwood KM070 mixer was used as a standard apparatus and five impeller designs with different shapes and surface areas were used. The efficacy of granulate formation was measured by adding an optically sensitive tracer to determine variations in active ingredient content across random samples of granules from the same size classes. It was found that impeller design influenced the homogeneity of the granules and therefore can affect final product performance. The variation in active ingredient content across granules of differing size was also investigated. The results show that small granules were more potent than larger granules.
