Knowledge of physical properties and phase equilibria is necessary for the design and optimization of the equipment for the production of distilled alcoholic beverages. In this paper the temperature dependence of the excess molar volumes of the ternary system ethanol + water + 1-pentanol in the temperature range 228.15 ? 323.15 K and atmospheric pressure, are presented due to the importance of 1-pentanol among the flavour compounds contained in this type of beverages. The excess molar volumes are negative over the whole homogeneous composition range, but tend to positive values towards the binaries ethanol + 1-pentanol and water + 1-pentanol. Because the design of current processes is strongly computer oriented, consideration was also given to how accurate the predictions of the SRK equations of state are. Different derived properties were computed due to their importance in the study of specific molecular interactions.
A novel formula of crosslinked polyvinyl alcohol (PVA) with glutaraldehyde (GTA), a tri-iodide complex, and glucono-δ-lactone (GDL) acid for gel dosimetry was investigated in the present study. The objectives of this study were to evaluate the formula’s dose response properties through spectrophotometry and possible reusability by reannealing. After production, the gel samples were irradiated from 1 to 70 Gy of gamma-rays from a Cs-137 source with a constant dose rate of 0.857 Gy/min. Spectrum data were obtained using a UV-Vis spectrophotometer and analyses were done for dose linearity, dose sensitivity versus GTA concentration, and absorbance profile versus time. The resulting unirradiated gel samples were colorless and transparent, while the irradiated samples turned to a reddish-brown hue with a peak absorbance response at 490 nm. Dose linearity results indicated R2 values of 0.9, 0.986 and 0.8 for GTA concentrations of 7 mM, 15 mM and 30 mM, respectively. Moreover, dose sensitivity is higher for lower concentrations of GTA. Time progression results indicated that the absorbance decreases within one day after irradiation and increases subsequently. Through reannealing for 24 hours at 45°C in an oven, a colorless material with an absorbance value identical to the unirradiated samples was finally made for samples irradiated from 1 to 20 Gy, while the 70 Gy irradiated sample had a significant decrease in color and absorbance peak. This radiochromic gel dosimeter is promising and should be useful for 3D radiation dose assessments. Further investigation of the formula and preparation techniques are suggested for future experiments.
While it is recognized that some medical workers could receive significantly higher radiation doses to their hands than the routinely monitored personal doses, accurate retrospective dosimetry of their hand exposure is still challenging. To solve this issue, a combination of electron spin resonance (ESR) measurement and fingernails is worth to be investigated. However, the application of fingernail ESR dosimetry requires establishing an effective protocol to eliminate the background signal (BKG) which changes due to mechanical stress and other unclear factors, so that the radiation doses would be precisely evaluated from the radiation-induced signals (RIS) only. Thus, the authors investigated possible applications of antioxidants to remove or reduce the BKG in fingernails. In the present study, the effectiveness of chemical treatment using the dithiothreitol (DTT) reducing reagent was examined in irradiated and unirradiated fingernails. Chemically and non-chemically treated fingernails were subsequently exposed to 20 Gy of 137Cs γ-rays and the time changes of the BKG and RIS were confirmed in two different storage conditions: vacuum chamber and freezer. The results show that the non-chemically treated fingernails displayed significant intra-individual variations in the peak-to-peak intensities of both BKG and RIS. RIS from chemically and non-chemically treated samples showed correlations after freezer storage; signals were more stable than the samples stored in the vacuum chamber. Moreover, while the BKG of non-chemically treated samples demonstrated higher levels than those chemically treated, the intra-individual variations were further reduced by the DTT treatment. Our results imply that the use of an antioxidant for hand washing of medical workers prior to starting their work could be effective in reducing the pre-existing free radicals in their fingernails. This also suggests a practical application of hand exposure monitoring using fingernails as a part of radiological emergency preparedness in occupations where radiation or radionuclides are used. Research for finding safer and easier-to-handle antioxidants is to be focused on in future studies.
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