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Volume 13, Issue 54 (8-2015)
Abstract
Earlier toxicological studies demonstrated that acrylamide is carcinogenic and most acrylamide in food is formed when asparagine amino acid reacts with certain naturally occurring sugars such as glucose.Inhibition, even reduction, of acrylamide formation during processing of foods, can help to produce more healthy food and, consequently, promote food safety. The objective of this study was to investigate the effects of the autolysed yeast of Saccharomyces cerevisiae, vitamins niacin (B3) and pyridoxine (B6) on acrylamide formation in chemical model. In this study the effects of different concentrations (0.025, 0.25 and 0.5 mmol) of autolysed yeast of Saccharomyces cerevisiae, vitamins B3 and B6 on acrylamide formation were evaluated in a chemical model. The acrylamide level was determined by Gas chromatography- mass spectrometry (GC/MS). According to the results vitamins B3, B6 and autolysed yeast of Saccharomyces cerevisiae, could reduce effectively acrylamide formation and vitamin B3 at concentration of 0.5 mmol was the most effective (p<0.05). This study indicated that these three additives could significantly reduce the acrylamide formation.
Volume 15, Issue 74 (0-0)
Abstract
Volume 17, Issue 11 (1-2018)
Abstract
This paper presents an experimental and numerical investigation of phase change material melting in a rectangular enclosure. The aim of this research is the study of the effect of the tilt angle of the enclosure on the flow structures and the melting rate. In the experimental section, the visualization of the melting process is carried out by the photography of the phase change material through a transparent enclosure. Then, the image processing of the photographs is performed to calculate the instantaneous liquid fractions. The variation of the solid-liquid interface by tilting the enclosure clearly implies the evolution of the flow structures in the liquid phase. Numerical simulation is performed using the enthalpy-porosity approach for tilt angles of 90, 45 and 0o and wall temperatures of 55, 60 and 70 oC. The results show that by decreasing the tilt angle from 90o to 45o and 0o, the melting times are 52% and 37% less than that of the vertical enclosure. Melting time reduction in the inclined enclosure is due to the formation of the vertical flow structures and thermal plums in the liquid phase. By Increasing the Stefan number from 0.36 to 0.43 and 0.55 the thermal energy storage increase by 5.4% and 13.8%, respectively. Also, a correlation is developed to predict the thermal energy storage in the tilt enclosures using nonlinear regression.
Volume 20, Issue 6 (June 2020)
Abstract
High corrosion resistance, proper mechanical properties, and biocompatibility of Ti-6Al-4V alloy make it suitable for medical (dentistry and orthopedic implants), military and electronic industries. The greatest disadvantages of this alloy are poor wear resistance, low fatigue strength and poor tribological properties. The aim of this study was to apply an adhesive coating to improve both corrosion and wear properties of the Ti-6Al-4V alloy. Surface modification of alloy was done by nitrogen plasma nitriding in both electrolyte plasma and atmosphere plasma environment. Finally, the TiN layer was coated on the modified samples, using cathodic arc evaporation technique. The microstructural investigation, surface morphology, and coating thickness were studied by field emission scanning electron microscope (FESEM) equipped with energy dispersive spectroscopy. The grazing incidence X-ray diffraction (GIXRD) was applied to study the phases in the coatings. The corrosion resistance was studied with potentiodynamic polarization and electrochemical impedance spectroscopy. The wear resistance and the coating coefficient of friction were tested with pin-on-disc machine. The corrosion resistance of the samples was improved by applying the coatings and the plasma-nitride/TiN double-layer coating showed the best corrosion resistance with current density of 1.46×10-7A/cm2 and corrosion potential of -0.3V. On the other hand, the lowest thickness reduction in wear test was observed in double-layer coatings, so that the thickness reduction for both double-layer coatings, was less than 4μm, after 300m sliding.
