Studia Universitatis Babeș-Bolyai Collection
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With a history of more than six decades (1955), Studia Universitatis Babeș-Bolyai (Studia UBB) is one of the leading academic journals in Romania.
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Item INVESTIGATION OF THE EFFECT OF A HYBRID DRYING METHOD ON THE COLOR QUALITY OF NECTARINE SLICES AND ENERGY CONSUMPTION(STUDIA UBB CHEMIA. Published by Babeş-Bolyai University, 2017-03-30) Fatmagül Mutlu DEMIREL; Osman İSMAILThe main objective of a product quality study for drying agricultural products without causing distortion is to reduce the product moisture value to a final moisture value while expending the least energy and time. In the first stage of this study, nectarine slices were dried in a microwave and cabinet dryer under different drying conditions. Experiments in the microwave dryer were done at four different power levels: 90, 180, 360, and 600 W. Hot air drying was done at two temperatures, 50 and 70 °C, with a constant air velocity (2.0 m/s). In the second stage, after those experiments, the hybrid drying method were constructed based on the color parameter, and moisture ratio. In the hybrid drying method, hot air drying was carried out with microwave pretreatment. The most effective hybrid drying method in terms of optimal drying time, energy consumption, and color parameters was found to be at 180 W microwave power and 70 °C.Item EVALUATION OF BLEACHING ON A CAD/CAM HYBRID CERAMIC MATERIAL(STUDIA UBB CHEMIA. Published by Babeş-Bolyai University, 2017-03-30) Bogdan CULIC; Cristina GASPARIK; Adrian Mihai VARVARĂ; Carina CULIC; Cristian Mihai DRAGOȘ; Laura SILAGHI DUMITRESCU; Diana DUDEAThe objective of our study was to test the bleaching effect of two whitening gels, on stained hybrid ceramic material used for Computer Aided Design/ Computer Aided Manufacturing technology. 40 rectangular specimens 12/14/1mm were prepared form Vita Enamic blocks. All specimens were accelerated stained, and distributed in two groups. Group 1 was bleached using Opalescence PF 15% (Ultradent, USA), group 2 was bleached using an experimental gel containing natural products. ΔE* (used to asses the color changes) was above the perceptibility threshold of 1.2 in 40%; and the WID (used to asses the bleaching process in dentistry) showed high units for both bleaching gels. Hybrid ceramics staining showed moderate results, while the bleaching effect was present, with no statistical difference between the discolorations produced by the two bleaching gels (p<0.05). SEM images showed that the bleaching gels did not affect the surface structure of the material.