Electrodeposition and Characterization of Zinc-Cobalt Alloy Coatings

Electrodeposited alloys are important in industry due to their properties which are superior to those of single metal layer. Zinc-cobalt alloys were co-deposited on gold substrate. Composition of the layers was established using SEM-EDX techniques. The influence of working parameters against stoichiometric composition of alloys was studied in order to find optimal conditions to achieve a desired final product. Some discussion about reaction mechanism was opened based on EIS diagrams. Application properties important for coating systems used in the automotive industry, such as friction behavior, adhesion, and corrosion behavior, were investigated on coatings with varying cobalt content. The corrosion resistance of the Zn-Co alloy layers was found to be better than the one of pure zinc coatings

Influence of pH Galvanic Baths on the Nickel Deposits

The influence of pH on cathodic and anodic current efficiency, surface quality and morphology of nickel deposit in the electrolyte solutions of the Watts bath type was investigated. Cathodic current efficiency of nickel deposit is maximum for electrolytic bath whose pH value is about 4 and decreases for an electrolytic bath with a higher pH. The deposited thickness is a significant parameter because the thickness determining may establish if the deposition corresponds to the destination application deposition or not; and the measurements were made by non-destructive physical methods. The properties of nickel deposits, brightness and hardness are influenced by the pH of the bath electrolyte. The surface morphology of nickel deposit was analyzed by scanning electronic microscopy (SEM). The results showed that the structure of nickel deposits is influenced by pH of the bath. The pH increasing causes structural changes on the deposits in fine to coarse, while the electrodeposited nickel at pH 6.21 has a compact morphology with many cracks

Studies About Electrochemical Plating with Zinc-Nickel Alloys

The electrochemical deposition of zinc and combinations with elements of the 8th group of the Periodic System (nickel, cobalt, iron) have good properties for anticorrosive protection, compare with pure zinc. For steel pieces, these films delay apparition and formation of white and red iron oxide. We used solutions with different concentrations of zinc chloride, nickel chloride and potassium chloride. For analyze the results we utilized the optic microscope and the X-ray diffraction

Influence of Technological Parameters on the Evolution of Nickel Films Deposited by Electrolysis

The influence of technological parameters on the structure of nickel layers electrodeposited on a copper substrate in a Watts bath has been studied. The complex influence of current densities, temperature and pH values on the formation of the deposition layers are compared. The surface morphology of the nickel films was analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). X-ray diffraction (XRD) was used to investigate the crystallinity of the prepared samples. The increase in the current density leads to fine crystallized films, while layers obtained at even higher current density have dendritic structures. The temperature increasing results in a structure change from fine to coarse

Chemical composition and temperature influence on the rheological behaviour of honeys

The purpose of this work was to examine the viscoelastic properties of Spanish honeys with various sugar contents [fructose (32 42 g/100 g honey), glucose (24 35 g/100 g honey), sucrose (0.0 3.4 g/100 g honey)]; concentrations (79 83 ◦Brix), and moisture levels (16 19 g/100 g honey) at different temperatures (5, 10, 15, 20, 25, 30, and 40◦C). Honey showed Newtonian behaviour, presenting a highly viscous part (loss modulus was much greater than the elastic modulus). The loss modulus (G ) and viscosity increased with moisture content and a decrease with temperature. Exponential and power law models were applied to fit loss modulus and viscosity data. Polynomial models were proposed to describe the combined effect of temperature, fructose, glucose, sucrose content, other sugars, non-sugar substance, and moisture content.Oroian, MA.; Amariei, S.; Escriche Roberto, MI.; Leahu, A.; Damian, C.; Gutt, G. (2014). Chemical composition and temperature influence on the rheological behaviour of honeys. International Journal of Food Properties. 17(10):2228-2240. doi:10.1080/10942912.2013.791835S222822401710Kaya, A., Ko, S., & Gunasekaran, S. (2008). Viscosity and Color Change During In Situ Solidification of Grape Pekmez. Food and Bioprocess Technology, 4(2), 241-246. doi:10.1007/s11947-008-0169-4Bhandari, B., D’Arcy, B., & Chow, S. (1999). Rheology of selected Australian honeys. Journal of Food Engineering, 41(1), 65-68. doi:10.1016/s0260-8774(99)00078-3CHEN, Y.-W., LIN, C.-H., WU, F.-Y., & CHEN, H.-H. (2009). RHEOLOGICAL PROPERTIES OF CRYSTALLIZED HONEY PREPARED BY A NEW TYPE OF NUCLEI. Journal of Food Process Engineering, 32(4), 512-527. doi:10.1111/j.1745-4530.2007.00227.xYanniotis, S., Skaltsi, S., & Karaburnioti, S. (2006). Effect of moisture content on the viscosity of honey at different temperatures. Journal of Food Engineering, 72(4), 372-377. doi:10.1016/j.jfoodeng.2004.12.017Saravana Kumar, J., & Mandal, M. (2009). Rheology and thermal properties of marketed Indian honey. Nutrition & Food Science, 39(2), 111-117. doi:10.1108/00346650910943217Oroian, M., Amariei, S., Escriche, I., & Gutt, G. (2011). Rheological Aspects of Spanish Honeys. Food and Bioprocess Technology, 6(1), 228-241. doi:10.1007/s11947-011-0730-4Oroian, M. (2012). Physicochemical and Rheological Properties of Romanian Honeys. Food Biophysics, 7(4), 296-307. doi:10.1007/s11483-012-9268-xCohen, I., & Weihs, D. (2010). Rheology and microrheology of natural and reduced-calorie Israeli honeys as a model for high-viscosity Newtonian liquids. Journal of Food Engineering, 100(2), 366-371. doi:10.1016/j.jfoodeng.2010.04.023Witczak, M., Juszczak, L., & Gałkowska, D. (2011). Non-Newtonian behaviour of heather honey. Journal of Food Engineering, 104(4), 532-537. doi:10.1016/j.jfoodeng.2011.01.013Gómez-Díaz, D., Navaza, J. M., & Quintáns-Riveiro, L. C. (2005). Rheological behaviour of Galician honeys. European Food Research and Technology, 222(3-4), 439-442. doi:10.1007/s00217-005-0120-0Gómez-Díaz, D., Navaza, J. M., & Quintáns-Riveiro, L. C. (2012). Physicochemical characterization of Galician Honeys. International Journal of Food Properties, 15(2), 292-300. doi:10.1080/10942912.2010.483616Mora-Escobedo, R., Moguel-Ordóñez, Y., Jaramillo-Flores, M. E., & Gutiérrez-López, G. F. (2006). The Composition, Rheological and Thermal Properties of Tajonal (Viguiera Dentata) Mexican Honey. International Journal of Food Properties, 9(2), 299-316. doi:10.1080/10942910600596159Bhandari, B., D’Arcy, B., & Kelly, C. (1999). Rheology and crystallization kinetics of honey: Present status. International Journal of Food Properties, 2(3), 217-226. doi:10.1080/10942919909524606Mossel, B., Bhandari, B., D’Arcy, B., & Caffin, N. (2003). Determination of Viscosity of Some Australian Honeys Based on Composition. International Journal of Food Properties, 6(1), 87-97. doi:10.1081/jfp-120016626Zaitoun, S., Ghzawi, A. A.-M., Al-Malah, K. I. M., & Abu-Jdayil, B. (2001). RHEOLOGICAL PROPERTIES OF SELECTED LIGHT COLORED JORDANIAN HONEY. International Journal of Food Properties, 4(1), 139-148. doi:10.1081/jfp-100002192Yoo, B. (2004). Effect of temperature on dynamic rheology of Korean honeys. Journal of Food Engineering, 65(3), 459-463. doi:10.1016/j.jfoodeng.2004.02.006Abu-Jdayil, B., Al-Majeed Ghzawi, A., Al-Malah, K. I. ., & Zaitoun, S. (2002). Heat effect on rheology of light- and dark-colored honey. Journal of Food Engineering, 51(1), 33-38. doi:10.1016/s0260-8774(01)00034-6Mossel, B., Bhandari, B., D’Arcy, B., & Caffin, N. (2000). Use of an Arrhenius Model to Predict Rheological Behaviour in some Australian Honeys. LWT - Food Science and Technology, 33(8), 545-552. doi:10.1006/fstl.2000.0714Küçük, M., Kolaylı, S., Karaoğlu, Ş., Ulusoy, E., Baltacı, C., & Candan, F. (2007). Biological activities and chemical composition of three honeys of different types from Anatolia. Food Chemistry, 100(2), 526-534. doi:10.1016/j.foodchem.2005.10.010Giner, J., Ibarz, A., Garza, S., & Xhian-Quan, S. (1996). Rheology of clarified cherry juices. Journal of Food Engineering, 30(1-2), 147-154. doi:10.1016/s0260-8774(96)00015-5Ibarz, A., Pagán, J., & Miguelsanz, R. (1992). Rheology of clarified fruit juices. II: Blackcurrant juices. Journal of Food Engineering, 15(1), 63-73. doi:10.1016/0260-8774(92)90040-

STUDY ON THE EVOLUTION OF MICRO- AND MACROELEMENTS DURING THE WINEMAKING STAGES: THE IMPORTANCE OF COPPER AND IRON QUANTIFICATION

Knowledge of the concentration of mineral elements from winemaking products, particularly from the final product is important because of their influence on wine quality. Some metal ions such as iron and copper can induce haze formation and changes in the sensory proprieties of wine. The presence of heavy metals in wine is due to different factors including vineyard soil, agricultural practices (the use of fertilizers and pesticides), and can be at the same time a result of environmental pollution. In addition, the acidity of wine and grape must (freshly pressed grape juice) can dissolve Cr, Cu, Ni, and Zn from winemaking equipment like pumps and taps. As wine is the most widely consumed alcoholic beverage, analytical control of mineral elements content is required during the whole process of wine production, from the grapes used to the final product. In this study the content of micro- and macroelements in grape pomace, yeast sediment, grape must and wine was determined by inductively coupled plasma-mass spectrometry (ICP-MS). Samples of winemaking products originating from five grape varieties were analyzed in four forms in order to determine to what measure the values varied the PCA (Principal component analysis). The obtained results using PCA highlighted major differences in the content in trace elements between samples

ELECTROCHEMICAL BIOSENSOR BASED ON THE USE OF SPE FOR THE DETECTION OF IRON CONTENT IN WINE

The purpose of this paper is to develop a new method for iron analysis in wine. The determination of iron in winemaking products is particularly important because a content higher than 10 mg/L can lead to turbidity or a change in color, which causes ferric casse. The new method is based on the use of screen printed electrodes (SPE), previously immobilized with Protein A-Agarose and connected to a potentiostat which displays a cyclic voltammogram. To verify the method, the samples of wine were also analysed by a reference method, namely AAS. In order to visualize the deposition of the iron ions on the electrode, surface analyses were perfomed by a microscope which combines confocal microscopy with white light interferometry. The main features of this sensor are simplicity of operation, good sensitivity and low limit of detection

Production of Cellulosic Ethanol from Enzymatically Hydrolysed Wheat Straws

The aim of this study is to find the optimal pretreatment conditions and hydrolysis in order to obtain a high yield of bioethanol from wheat straw. The pretreatments were performed with different concentrations of sulphuric acid 1, 2 and 3% (v/v), and were followed by an enzymatic hydrolysis that was performed by varying the solid-to-liquid ratio (1/20, 1/25 and 1/30 g/mL) and the enzyme dose (30/30 µL/g, 60/60 µL/g and 90/90 µL/g Viscozyme® L/Celluclast® 1.5 L). This mix of enzymes was used for the first time in the hydrolysis process of wheat straws which was previously pretreated with dilute sulfuric acid. Scanning electron microscopy indicated significant differences in the structural composition of the samples because of the pretreatment with H2SO4 at different concentrations, and ATR-FTIR analysis highlighted the changes in the chemical composition in the pretreated wheat straw as compared to the untreated one. HPLC-RID was used to identify and quantify the carbohydrates content resulted from enzymatic hydrolysis to evaluate the potential of using wheat straws as a raw material for production of cellulosic ethanol in Romania. The highest degradation of lignocellulosic material was obtained in the case of pretreatment with 3% H2SO4 (v/v), a solid-to-liquid ratio of 1/30 and an enzyme dose of 90/90 µL/g. Simultaneous saccharification and fermentation were performed using Saccharomyces cerevisiae yeast, and for monitoring the fermentation process a BlueSens equipment was used provided with ethanol, O2 and CO2 cap sensors mounted on the fermentation flasks. The highest concentration of bioethanol was obtained after 48 h of fermentation and it reached 1.20% (v/v)

Study on Kinetics of Trans-Resveratrol, Total Phenolic Content, and Antioxidant Activity Increase in Vine Waste during Post-Pruning Storage

There is increasing evidence surrounding the health benefits of E-resveratrol; this has triggered interest in stilbenoids in grapes, wine, and by-products. On the one hand, there is an enormous amount of underutilized vine waste, rich in bioactive substances during wine production. On the other hand, there is a growing demand for promising phytochemicals, for dietary and pharmaceutical purposes. Vine shoots are promising sources of stilbenoids; they have economic potential because they are sources of high-value phytochemicals. Recent studies have shown that, due to biosynthesis pathway genes, especially STS (forming trans-resveratrol), which is abundant during storage periods of vine shoots—trans-resveratrol accumulates up to 40-fold. The objective of this research was to determine the most economical part of vine waste to be exploited, and to study the kinetics of resveratrol increase in a 90-day period, to determine the optimal storage period to reach a maximum trans-resveratrol content. Total phenolic content (TPC) and antioxidant activity (AA) were studied to determine possible correlations. In Fetească Neagră vine shoot varieties stored at laboratory temperatures, trans-resveratrol content increased to a maximum (2712.86 mg/kg D.W.) at day 70, and then slightly decreased until day 90. TPC remained constant and there was a slight increase in AA. Vine shoots contained the largest amounts of trans-resveratrol (1658.22 mg/kg D.W.), followed by tendrils (169.92 mg/kg D.W.), and leaves (43.54 mg/kg D.W.)

Study on Kinetics of Trans-Resveratrol, Total Phenolic Content, and Antioxidant Activity Increase in Vine Waste during Post-Pruning Storage

There is increasing evidence surrounding the health benefits of E-resveratrol; this has triggered interest in stilbenoids in grapes, wine, and by-products. On the one hand, there is an enormous amount of underutilized vine waste, rich in bioactive substances during wine production. On the other hand, there is a growing demand for promising phytochemicals, for dietary and pharmaceutical purposes. Vine shoots are promising sources of stilbenoids; they have economic potential because they are sources of high-value phytochemicals. Recent studies have shown that, due to biosynthesis pathway genes, especially STS (forming trans-resveratrol), which is abundant during storage periods of vine shoots—trans-resveratrol accumulates up to 40-fold. The objective of this research was to determine the most economical part of vine waste to be exploited, and to study the kinetics of resveratrol increase in a 90-day period, to determine the optimal storage period to reach a maximum trans-resveratrol content. Total phenolic content (TPC) and antioxidant activity (AA) were studied to determine possible correlations. In Fetească Neagră vine shoot varieties stored at laboratory temperatures, trans-resveratrol content increased to a maximum (2712.86 mg/kg D.W.) at day 70, and then slightly decreased until day 90. TPC remained constant and there was a slight increase in AA. Vine shoots contained the largest amounts of trans-resveratrol (1658.22 mg/kg D.W.), followed by tendrils (169.92 mg/kg D.W.), and leaves (43.54 mg/kg D.W.)