Improved range-profiling algorithm of rainfall rate from aspaceborne radar with path-integrated attenuation constraint

A range-profiling algorithm for rainfall rate retrieval from a single-frequency downward-looking spaceborne radar is presented. The algorithm is based on a linear reformulation of the radar equation. The path-integrated attenuation given by the surface echo measurement is used as a constraint for normalizing the range-gated rain echoes. The expected performances are studied analytically and compared with those of the approach of W. Hitschfeld and J. Bordan (1954). The stability and accuracy of the rainfall profile retrieval in the presence of various types of errors are pointed out and illustrated by means of numerical simulations of data processing from a spaceborne rain radar operating basically at Ku band     

Analysis of cross-beam resolution effects in rainfall rate profileretrieval from a spaceborne radar

The performance (stability and accuracy) of a range profiling algorithm (kZS), using the measurement of surface echo as a constraint on total path integrated attenuation, for rainfall retrieval from a spaceborne radar was presented and discussed by C. Matzler (1987). Omitting other causes of errors previously examined, the present authors focus specifically on possible bias due to nonuniform beam filling effects. This problem is studied analytically to identify the physical origin of the biasing terms. In addition, bias in rainfall profile estimates is quantified through simulations of Ku-band spaceborne radar data processing, featuring the intercept of a raincell model by the downward looking radar beam     

Study of C.I. Reactive Yellow 145, C.I. Reactive Red 238, and C.I. Reactive Blue 235 dyestuffs in order to use them in color formulation. Part 1: characterization and compatibility

Generally, textile dyeing is based on a mixture of several dyestuffs used in different proportions to achieve the desired-colors. The dyes used in a mixture should react with the fiber similarly; thus they must be compatible among themselves. So, to realize mixtures it is indispensable to study the compatibility of dyes, in order to ensure optimal dyeing formulation. This paper describes the characterization and studies the compatibility of three cold bifunctionnal reactive dyes (C.I. Reactive Yellow 145, C.I. Reactive Red 238, and C.I. Reactive Blue 235) in order to explore the possibility to use them in mixtures. The dye compatibility was studied based on several criteria such as dye extinction coefficients, exhaustion and fixation yield rates, adsorption kinetics, and adsorption isotherms. The exhaustion and fixation yield rates of all three dyes was compared between them and their adsorption kinetics and adsorption isotherms models were drawn and discussed. Between the different studied models, the Elovich model presents the best model describing the kinetics of different dyes, and Freundlich model presents the best model for analyzing the adsorption isotherms. The obtained results show that the analyzed dyes are perfectly compatible and have the same dyeing properties. They present close extinction coefficients as well as similar exhaustion and fixation yield rates.     

Application of genetic algorithm to color recipe formulation using reactive and direct dyestuffs mixtures

Color reproduction is a science in constant development. In this article, a new model to solve the color recipe prediction problem using a genetic algorithm is proposed. The objective is to optimize the color recipe prediction stage by determining the dyes to use in a mixture and their respective proportions to reproduce the target color. Two ranges of dyes were used for dyeing 100% cotton woven fabrics: three reactive dyes (CI Reactive Red 238, CI Reactive Yellow 145, and CI Reactive Blue 235) and four direct dyes (CI Direct Orange 34, CI Direct Red 227, CI Direct Blue 85, and CI Direct Black 22). The criterion of optimization, in reproducing the desired shades, is to minimize the CMC color difference between the desired reference color and the color resulting of the predicted recipe. The proposed algorithm revealed good results with small CMC color differences between target and reproduced colors. The effectiveness of the algorithm was also evaluated and proven by calculating errors between the predicted concentrations in the proposed recipes and the actual concentrations.     

Separation of ultimate and technical esparto grass fibres: comparison between extraction methods

Esparto grass fibres are used as cordage or paper pulp. Ultimate and technical fibres used in pulp or cords have specific characteristics. Technical fibres have higher mechanical properties. However, ultimate fibres have a higher cellulosic rate, hence higher absorbency and retention capacity. To produce ultimate fibres, we must look for an appropriate method of extraction. In this paper, a method of extraction that gives cellulosic fibres without any damage is investigated and a comparison with other methods is also made. The structure of esparto grass technical fibres is discontinuous, where cellulosic fibres are found in matrix which contains pectin, lignin and hemicelluloses. The ultimate fibres from esparto grass have a length between 0, 2 and 3 mm and a diameter between 6 and 22 µm. This shows that ultimate fibres are very short; however, they have very interesting features. The chosen extraction method has many specifications: protecting properties using a combined method which is accomplished in a short time and which takes the ecological impact into consideration. In this work different stages are followed to obtain cellulosic fibres. These fibres are then characterised through several analyses such as scanning electron microscopy, X‐ray diffraction, diameter and rate of lignin elimination.     

Application of ant colony optimization to color matching of dyed cotton fabrics with direct dyestuffs mixtures

Color matching and recipe prediction is one of the most important aspects of color science. In this article, a new method using ant colony algorithm is developed to optimize the color formulation step. Four direct dyes, namely CI Direct Red 227, CI Direct Orange 34, CI Direct Blue 85, and CI Direct Black 22 were used and mixed to dye cotton fabrics. The aim is to reproduce the desired shades by determining the dyes and their respective concentrations to add in the dye bath. The criterion of optimization is to minimize the CMC color differences between the target color and the color obtained by the proposed recipes. The developed algorithm showed good performances with small color differences all lower than the unit.     

Study of C.I. Reactive Yellow 145, C.I. Reactive Red 238 and C.I. Reactive Blue 235 dyestuffs in order to use them in color formulation. Part 2: modeling and optimization of dyeing performances

Abstract

This article models and optimizes the effect of dyeing parameters on obtained color of fabric samples dyed with three cold bifunctional reactive dyes, namely, C.I. Reactive Yellow 145, C.I. Reactive Red 238 and C.I. Reactive Blue 235, in order to use them in color formulation. The studied dyeing parameters are electrolyte concentration, alkali concentration, liquor-to-fiber ratio and temperature of dyeing process. The influence of these parameters was analyzed for four different shades: 0.1%, 1%, 2% and 4%. Two criteria of evaluation are studied and optimized: the exhaustion and the fixation yields. Linear modeling of optimal concentrations of electrolyte and alkali according to the dye concentration was developed, allowing the calculation of optimal quantities which should be added to the dye bath for any dye concentration. Color coordinates and fastness (washing, rubbing and light fastness) of samples dyed with optimal conditions are also evaluated and discussed.     

Colour recipe prediction using ant colony algorithm: principle of resolution and analysis of performances

This paper presents a new method for colour recipe prediction using ant colony optimisation. Three reactive dyes, namely CI Reactive Yellow 145, CI Reactive Red 238 and CI Reactive Blue 235, were used for colour formulation. Samples of 100% cotton fabrics were used for dyeing. The objective was to assure, control and optimise the colour formulation step by determining the dyes to be applied and their respective concentrations to reproduce the desired shades. The criterion of optimisation is to minimise the colour differences [Colour Measurement Committee (2:1)] between the target colour and the colour obtained by the proposed recipe. Errors between the proposed recipe and actual concentrations are also evaluated. The developed algorithm showed good performances with small colour differences between the target and reproduced colours (all lower than 0.7).