Iskanje po katalogu digitalne knjižnice

Opis: The paper briefly describes a mathematical model of the colorant mixture colour sensitivity to concentration errors and the numerical estimates of the related quantities. Features of the theoretical model are illustrated with the results of a number of numerical experiments in which the optical data of a few basic dyes applied to textile fabric were used to predict the sensitivities of recipes for sets of target colours spaced regularly in the colour solid. The rest of the article deals with the question whether the predicted values of recipe colour sensitivity provide useful information about the repeatability of recipe colour. The results of a few groups of laboratory experiments involving the textile fabric dyeing with basic dyes have been analysed with this question in mind.
Ključne besede: textile dyeing, basic dyes, recipe colour, colour, color repeatability, colour sensitivity, concentration errors, mathematical model
Objavljeno v DKUM: 05.07.2017; Ogledov: 1258; Prenosov: 118
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Opis: The essential question of the paper "Can the predicted sensitivity to random and/or proportional dye concentration errors assist in selecting the most repeatable recipes?" was investigated using the laboratory dyeing of acrylic fabric with basic dyes. When the dye strength errors were not involved, the biggest scattering of the recipe colour in repeated dyeings was observed in the cases of light neutral target colours, where the predicted sensitivity to random concentration errors was the highest. For a few low-saturated targets, eight recipes with different predicted sensitivities to random errors were treated. In six cases out of the seven treated, those recipes less sensitive to random concentration errors generally performed better than the more sensitive ones, but the correlation was rather weak. For those cases whenthe dye strength errors were included, experiments were also carried out with several different recipes for a neutral medium-lightness target colour.
Ključne besede: colour, textile dyeing, computer aided reciping, recipe colour sensitivity
Objavljeno v DKUM: 01.06.2012; Ogledov: 1964; Prenosov: 37
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Opis: The decolouration and mineralization of reactive dye C.I. Reactive Black 5, a well-known representative of non-biodegradable azo dyes, by means of ultrasonic irradiation at 20, 279 and 817 kHz has been investigated with emphasis on the effect of various parameters on decolouration and degradation efficiency. Characterization of the used ultrasound systems was performed using calorimetric measurements and oxidative species monitoring using Fricke and iodine dosimeter. Experiments were carried out with low frequency probe type, and a high-frequency plate type transducer at 50, 100 and 150 W of acoustic power and within the 5-300 mgžL initial dye concentration range. Decolouration, as well as radical production, increased with increasing frequency, acoustic power, and irradiation time. Any increase in initial dye concentration results in decreased decolouration rates. Sonochemical decolouration was substantially depressed by the addition of 2-methyl-2-propanol as a radical scavenger, which suggests radical-induced reactions in the solution. Acute toxicity to marine bacteria Vibrio fischeri was tested before and after ultrasound irradiation. Under the conditions employed in this study, no toxic compounds were detected after 6 h of irradiation. Mineralization of the dye was followed by TOC measurements. Relatively low degradation efficiency (50% after 6 h of treatment) indicates that ultrasound is rather inefficient in overall degradation, when used alone.
Ključne besede: textile industry, wastewater treatment, textile dyeing, reactive dyes, azo dyes, decoloration, ultrasound, degradation, decoloration kinetics, oxidizing species
Objavljeno v DKUM: 01.06.2012; Ogledov: 2250; Prenosov: 97
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Opis: This article gives a summary of the most commonly used ecologically unfriendly processes for the reduction and oxidation of vat and sulphur dyes. It also describes the new alternatives that are in the development stage and could be important in the near future. Sodium dithionite as the dominant reducing agent produces large amounts of sodium sulphate, and also toxic sulphite and thiosulphate as by-products. Consequently, high amounts of hydrogen peroxide and alkali are required for the treatment of effluents, which add to the cost of the process. Attempts have been made to use organic biodegradable reducing agents, enzymes, catalytic hydrogenation, and also indirect or direct, electrochemical reductive methods that employ a redox mediator (electron-carrier). The reduction has also been carried out via the dye radical molecule or, in the case of indigo, by direct electrochemical reduction using graphite as the electrode material. Physical techniques, for example using ultrasound, magnetic fields or UV have been shown to be effective only when used to accelerate methods using classical reduction and oxidation processes. However, although these methods offer some environmental benefits, there is still no satisfactory alternative reducing and/or oxidising agent available today.
Ključne besede: textile dyeing, vat dyes, sulphur dyes, reduction, oxidation, catalysis, ecology, organic agents, electrochemistry, ultrasound, magnetic field, UV application, biotechnology
Objavljeno v DKUM: 01.06.2012; Ogledov: 3143; Prenosov: 120
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Opis: A regularity of the predicted sensitivities to random and proportional dye concentration errors in regard to the position of target colour has been observed for the case of dyeing acrylic with basic dyes. The sensitivity of the recipe colour to random dye concentration errors is highest for light neutral target colours and is almost negligible for dark-shade recipes. Recipes for less saturated targets are slightly more sensitive than recipes for more saturated targets of equal lightness. The span of the sensitivities to weighing error of the recipes matching a given target varies with the position of the target in colour space. By contrast, the sensitivity of recipes to dye strength error is the highest at medium to low lightness for neutral and near neutral target shades. The span of sensitivities of the recipes for any such particular target is broad, with some having low sensitivity to strength errors. Recipes for the target colours at the "lighter" part of the gamut border were the least sensitive to strength errors.
Ključne besede: colour, textile dyeing, computer aided reciping, recipe's colour sensitivity
Objavljeno v DKUM: 01.06.2012; Ogledov: 1825; Prenosov: 39
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