نشریه علوم و فناوری رنگ
سال پانزدهم شماره 4 (پیاپی 58، زمستان 1400)

Design is one of the most critical aspects of evaluating Persian rugs. While Persian rugs are woven in different designs, their unique patterns distinguish them from other rug styles such as Turkish, Indian and Chinese. In this study, the classification of two categories of Persian rugs (Lachak Toranj and Torkaman Geometric) was followed using Support Vector Machine (SVM) and based on Fourier feature. In this regard, the grayscale images of 60 rugs with different designs were collected. Using the Fourier transform, the unique feature of these two rugs’ categories were extracted and used for classification. For this purpose, a two-class support vector machine was used. According to the results, the SVM classification method can classify these two categories of rugs with an accuracy of 89% by using the polar Fourier feature.

In this study, two 2-aminobenzothiazole derivatives were prepared by the reaction of appropriate substituted anilines with potassium thiocyanate in acetic acid followed by mild cyclization oxidation reaction with bromine at room temperature. Then, 2-aminobenzothiazole and each of the two synthesized amines were diazotized with nitorsyl sulfuric acid and coupled with 5-chloro-8-hydroxy quinoline to prepare corresponding heteroarylazo dyes. Their solvatochromism was evaluated in different solvents. The effects of acid and base on the absorption maximum wavelengths of the compounds were also studied. From the optical spectra, in each case, the isosbestic points indicate that the two species are in equilibrium. For all of the compounds under investigation, the dependence of the absorbance on the pH value gives sigmoid curves. The acidity constants (pKa) of the dyes were also determined using the spectrophotometric method in an ethanol-water mixture (80:20, v/v) at 20-23°C. Besides, density functional theory (DFT) calculations were carried out in order to compare the energies of proposed azo and hydrazone tautomers of the dyes.