JOURNAL OF COLOR SCIENCE AND TECHNOLOGY
Year:2014 | Volume:8 | Issue:3|Papers Count:9

To make a white surface of ceramic glazes, zirconium silicate (zircon) particles are dispersed in the glaze body. Due to the high difference between the refractive index of zircon particles and that of the glazed body, the surface of the glaze scatters and reflects most of the light. Since zircon is expensive, some research has been done to find a cost-effective alternative for it. In this paper zircon was substituted by CaO, MgO, Al2O3 and also aluminum silicate as frit in the ceramic glaze and the effects on the physical properties of the surface were studied. Some samples with these materials were prepared and the reflectance spectra, whiteness index and the color parameters in CIEL*a*b* color space were studied. To study the composition and microstructure of the samples SEM and XRD experiments were performed. The results shown the sample which some part of zircon in the opacifier layer (engobe) was substituted by new compounds, had almost the same properties as full zircon sample.

Due to the difference between price and value of natural versus synthetic dyes, it has always been very important to distinguish these two categories for handmade carpet. This study aimed to investigate Near-IR spectrometry technique to identify natural madder and synthetic dyes used in handmade carpets. To do this woolen samples with two major races (Baluchi and Kermanshahi) were dyed with madder dye with alum and tin chloride mordant, and also synthetic dyes to provide conventional red-colored shades. The 60 dyed samples including of 24 madder, a set of 10 mixed (combination of Madder and synthetic dyes), 26 synthetic dyes, and 5 cases gotten from carpet, and in total 65 samples were prepared. Results showed that the spectral reflectance of the madder samples has an increasing slope in NIR region while the NIR spectral reflectance of synthetic dyes does not show any noticeable increasing trend. Considering the obtained results of this research, NIR spectrometry can be a feasible method to distingush between madder and synthetic dyes and it was quiet possible for the test samples with almost no errors. However, investigating on more samples would be suggested. Note that it is not possible to detect samples dyed with a mixture of madder and synthetic dyes. The mixed samples were presented in one of the two groups; synthetic or madder.

The main aim of this study is investigation of the reactive dye removal efficiency from wastewater by using nanofibers functionalized with b-cyclodextrin (b CD) through the immersion method. At first, polyacrylonitrile (PAN) nanofibers for the removal of three reactive dyes of CI Reactive Blue 13, C.I. Reactive Blue 21 and C.I. Reactive Red 2 from simulated wastewater were used. The dye removal efficiency for the dyes mentioned was 4.7, 22.5 and 3.4 %, respectively. Then, PAN/ b CD10 and PAN/ b CD50 nanofibers, which had 10 and 50 wt% of b CD, respectively, were electrospun. It was found that dye removal efficiency of PAN/ b CD10 nanofiber mats for the dyes mentioned was 8.3, 28.1and 10 %, respectively. Also, dye removal efficiency of PAN/ b CD50 nanofiber mats was obtained to be 31, 49 and 25%. Based on the results, dye removal efficiency of reactive dye wastewater was increased due to the increase in b CD concentration. Increasing PAN/ b CD50 nanofibers weight from 0.01 to 0.1 g tended to increase dye removal efficiency of C.I Reactive Blue 21 dye wastewater from 49% to 86.4%.

Dyes are one of the wastewater pollutants that use of them is increasing every day. In this study, the dye degradation efficiency with Zn-TiO2 was investigated using the sun as a light source. The effect of zinc on dopant activity and kinetics of dye degradation from wastewater was also investigated. Dopant was made with synthesis induction- evaporation method. The experiments were performed in a continuously photo reactor throughout the day. According to the results, at pH of 6.9, 50 mg /L of dye concentration, 50 mg/m2 catalyst concentration and Zn /Ti equal to 53% within 5 h; dye removal and organic degradation efficiency were obtained 85 and 60 %, respectively. According to the results, the reaction kinetics was pseudo-first-order equation.

In this study, radiation curable carboxylated urethane acrylate as an anionic polymeric dispersant with dimethylol propionic acid (DMPA), isophorone diisocyanate (IPDI), hydroxyethyl methacrylate (HEMA) in presence of dibutyltin dilaurate (DBTDL) as catalyst and acetone were synthesized. Then the carboxylic groups in dispersants were neutralized with triethylamine (TEA). Molecular structure of anionic polyurethane acrylate dispersants (AUAD) were characterized by fourier transforms infrared spectroscopy (FT-IR). Moreover, the dispersants were used for dispersing of TiO2 and Si 2 and the quality and quantity of particles dispersion were examined by Grindometer. Results show that in presence of carboxylate groups in backbone of polymer significantly reduce the time of dispersing. Also dispersion stability of the particles in the suspension was increased. Also the relationship between the increasing of polyurethane molecular weight and its work as a dispersant was discussed.

Different properties of an ambient temperature phosphate coating containing cobalt ions were studied on a steel substrate. Surface treatment on the phosphate coating bath was conducted at T=25oC, pH=3.1 and t=30 min. Different analytical techniques including linear polarization, scanning electron microscope (SEM), EDX and Pull off test were employed in order to evaluate the phosphate coating properties. The results obtained from the polarization test revealed that corrosion resistance of the phosphate coating was enhanced in the presence of cobalt ions. SEM micrographs showed a better surface coverage for the cobalt induced phosphate coating. Results obtained from the pull off test also showed that the surface treatment of the steel substrate by phosphate coating reduced adhesion loss of the epoxy coating after 30 days immersion in 3.5 wt% NaCl solution. The decrease in the adhesion loss was more pronounced in the case of using cobalt ions in phosphate coating.

This work intends to study the possible effect of reference electrode impedance on the working electrode impedance. For this purpose, various electrode/electrolyte systems were examined by electrochemical impedance spectroscopy (EIS) using reference electrodes having different impedance. In the experiments, working electrode impedance were around 1 and 10 kohm. cm2; and the reference electrode impedance were in the range of 1-10 kohm. The results showed that utilizing reference electrode with highest impedance resulted in distortion from actual impedance spectra in high or low frequency region which is of particular importance for corrosion inhibition studies.

Patination or producing the appearance of age has a great importance in the restoration of historical relics and furniture industry. In this research, patination of white poplar wood (Populus alba L) with Diethanolamine (DEA) and its resistance against weathering was investigated. Treated and untreated samples artificially were weathered for 300 and 800 hours, regarding ASTM 2565-99. Structural changes were investigated by application of Colorimetery, ATR-FTIR spectroscopy and Scanning Electron Microscopy. Results showed that DEA reacts with carbonyl group in hemicelluloses and syringyl unit of lignin. It causes to increase of darkness, yellowness and redness of wood. In the first stage of weathering (300 hours) photooxidation of lignin localized on guaiacyl unit, but in the second stage (800 hours) syringyl unit of lignin was degraded. Patination does not protect the white poplar wood against weathering for long time.

In order for a color matching model to be able to predict the correct and precise amounts of colorants to achieve a certain color, numerous sets of information regarding the effective parameters of the colored system is required. These parameters include the absorbance and scattering coefficients of colorants, relations between total and internal reflection of a colored layer, basic assumptions relating to incident light interactions with and without the colored layer, geometry and size of the scattering particles, etc. Additionally a colored layer could be transparent, translucent or opaque. Various models such as physical, numerical, intelligent and hybrid models attempt to present a correct prediction of the amounts of components to give the precise color through determining the contribution of each effective parameter which may lead to new formulae. In the present study, a variety of such models and their various applications are reviewed. Most of the well-known physical models such as Kubelka-Munk, Four- Flux, Many-Flux, Chandrasekhar, inverse adding doubling, Monte Carlo, representative layer theory and even intelligent models such as artificial neural network models for optimal usage are herewith described.