Predicting changes in the color of powders: Does Melamed's model fit to real industrial powders?

In 1963, Melamed proposed a model that expressed reflectance of a powder described as a population of spherical particles of unique diameter as a function of size, shape, and optical characteristics of the powder. This article shows how this model has been adapted to fit to industrial powders. An example of use for industrial quartz is given. © 2004 Wiley Periodicals, Inc. Col Res Appl, 29, 413–419, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20058     

A spectrophotometric color matching algorithm for precolored fiber blends

In this article, a spectrophotometric color matching algorithm based on Stearns‐Noechel model is proposed. This algorithm was run to predict recipes for 48 viscose blends. Color differences between the original blend samples and the calculated were expressed in CIELAB units (10°standard observer). M (the empirical constant in Stearns‐Noechel model) value was determined by median analysis. When M equals to 0.09, the best fit was obtained for three‐components fiber blends. In that case, the maximum color difference is 1.22 CIELAB units and the average computed color difference is 0.56 CIELAB units for 36 three‐components fiber blends under D65 illuminant. When M is from 0.03 to 0.06, the best fit was obtained for four‐components fiber blends. In that case, the maximum color difference is 4.48 CIELAB units and the average computed color difference is 1.02 CIELAB units for 12 four‐components fiber blends under D65 illuminant. It is demonstrated that the algorithm can be used in color matching of fiber blends. © 2009 Wiley Periodicals, Inc. Col Res Appl, 34, 108–114, 2009     

Color mixing and color separation of pigments with concentration prediction

In this study, we propose a color mixing and color separation method for opaque surface made of the pigments dispersed in filling materials. The method is based on Kubelka–Munk model. Eleven different pigments with seven different concentrations have been used as training sets. The amount of concentration of each pigment in the mixture is estimated from the training sets by using the least‐square pseudo‐inverse calculation. The result depends on the number and type of pigments selected for calculation. At most we can select all pigments. The combinations resulted with negative concentrations or unusual high concentrations are discarded from the list of candidate combination. The optimal pigment's set and its concentrations are estimated by minimizing the reflectance difference of given reflectance and predicted reflectance. © 2008 Wiley Periodicals, Inc. Col Res Appl, 33, 461–469, 2008     

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.     

Process optimization of solvent based polybenzimidazole adhesive for aerospace applications

The use of adhesive bonding for high temperature applications is becoming more challenging because of low thermal and mechanical properties of commercially available adhesives. However, the development of high performance polymers can overcome the problem of using adhesive bonding at high temperature. Polybenzimidazole (PBI) is one such recently emerged high performance polymer with excellent thermal and mechanical properties. It has a tensile strength of 160 MPa and a glass transition of 425 °C. Currently, PBI is available in solution form with only 26% concentration in Dimethyl-acetamide solvent. Due to high solvent contents, the process optimization required lot of efforts to form PBI adhesive bonded joints with considerable lap shear strength. Therefore, in present work, efforts are devoted to optimize the adhesive bonding process of PBI in order to make its application possible as an adhesive for high temperature applications. Bonding process was optimized using different curing time and temperatures. Epoxy based carbon fiber composite bonded joints were successfully formed with single lap shear strength of 21 Mpa. PBI adhesive bonded joints were also formed after performing the atmospheric pressure plasma treatment of composite substrate. Plasma treatment has further improved the lap shear strength of bonded joints from 21 MPa to 30 MPa. Atmospheric pressure plasma treatment has also changed the mode of failure of composite bonded joints.     

A metaheuristic‐based approach to optimizing color design for military camouflage using particle swarm optimization

Enhancing an existing military camouflage is an important component during the assessment of military camouflage. The current study proposed a new and practical approach to enhancing the undetectability of a military camouflage using particle swarm optimization (PSO). Eight different locations (20 × 50 pixels) in the one swamp background were selected to be the place of a human‐shaped target. The PSO would generate newly proposed camouflage as an empirical parameter based on the lower and the upper bounds from selected four different colors in swamp background. The predictive algorithm was applied to adjust the optimum shift of %L*, %a*, and %b* from the original to the empirical parameter. Thirty participants were recruited to evaluate the original and newly proposed camouflages. Paired sample t test indicates that the newly proposed military camouflage had a significant lower camouflage similarity index value and a longer detection time. The PSO shows to be a method with good results; however, a comprehensive study using multiple backgrounds and patterns would be required to generalize the methodology to other background environments or camouflage patterns.     

A colorizer for use in determining an optimal ophthalmic tint

A colorizer for use in the provision of an ophthalmic tint is described. The design differs from that of an earlier model in that the spectral power distribution of the light in the instrument is very similar to the spectral power distribution obtained when tinted glasses are worn under typical lighting. The similarity in spectral power is obtained notwithstanding the fact that the instrument uses an additive mixture of filtered light, whereas tinted lenses use a subtractive mixture of dyes. The precision of color selection is high, and this precision is shown to be necessary to optimize reading fluency. Because of the similarity in spectral power distribution, it is possible to examine the effect of ophthalmic tints not only on reading fluency, but also on the perception and naming of colored surfaces, and the examination can be undertaken by patients who have color vision anomalies. Compared with the earlier design, the use of a diffuse source and seven colored filters reduces the requirement for precision in alignment of components; the variation in color from one instrument to another is, therefore, small, allowing a single calibration for all instruments. This calibration permits the matching of colored ophthalmic lenses to a given colorizer setting, using a computer algorithm which enables practitioners with color vision deficiencies to undertake ophthalmic colorimetry. © 2001 John Wiley & Sons, Inc. Col Res Appl, 26, 246–253, 2001     

基于理论的有机工质管壳式冷凝器构形优化

建立考虑传热耗散率和总泵功率的线性加权复合函数,在总冷凝率和总传热面积一定的条件下以复合函数最小为目标,对有机工质的管壳式冷凝器进行构形优化,得到最小复合函数和冷凝管最佳外径。结果表明：冷凝器最优构形与初始设计结构相比,总耗散率提高了10.70%,而总泵功率和复合函数分别降低了54.94%和6.46%。这说明复合函数牺牲了一定的传热性能,使得冷凝器流动性能显著提高,最终使得其综合性能得到提高。选择合适的冷凝管数目可实现复合函数二次最小化。将理论应用到有机工质管壳式冷凝器的构形优化中,为其结构优化设计提供了新的指导,这一方法可进一步推广到有机工质循环系统的优化设计中。     

Designing sustainable alternatives for batch operations using an intelligent simulation–optimization framework

The drive towards sustainability has compelled the batch process industries to implement the concept of environmentally friendly plants. However, the temporal nature of processing in these processes obviates the application of traditional waste minimization, material recycling, or energy integration schemes. Further, most of the existing methodologies for generating sustainable alternatives are restricted to specific problems, such as reaction byproduct, wastewater, or solvent minimization. In this paper, we propose an intelligent simulation–optimization framework for identifying comprehensive sustainable alternatives for batch processes. We differentiate between wastes generated by the reaction–separation process and cleaning wastes. A P-graph-based approach is used for identifying the root cause of process waste generation and generating broad design alternatives. Specific variable-level design solutions are then identified and evaluated using process simulation. The cleaning wastes resulting from the optimized process are also minimized using a source-sink allocation method that allows design of recycle network structure. A multi-objective stochastic optimization method is used to integrate the analysis so that the overall process economic and environmental footprint is optimized. We illustrate the proposed methodology using a well-known literature case study involving reaction, distillation and washing operation.