The effect of unit k/s calculation and spectral overlapping on the performance of color matching

There are several approaches to dyeing recipe formulation in the textile industry, because the accuracy of computer recipe prediction is not very high. There are several theories such as colorimetric and spectrophotometeric appraches on color reception. This work addressed the effect of the calibration method as the calculation of unit k/s and spectral overlapping of the components of the mixture on the accuracy of recipe prediction in dyeing nylon with acid dye. To this aim, the unit k/s was calculated using single and binary mixture samples. Two types unit k/s were used for the recipe prediction of ternary mixture dyed samples with low and high overlapping reflectance spectra. The obtained results indicated that the unit k/s of single component differed from the unit k/s of bicomponent mixture. The accuracy of recipe prediction using unit k/s of single component was less than that of the binary mixture. However, the performance of the recipe prediction of high level overlapping was found to be more than that of the low level overlapping mixture. Subsequently, the accuracy of color matching depended on the reflectance spectra similarity (spectral overlapping) of the components of the mixture.     

Textile colour matching using linear and exponential weighted principal component analysis

In this work, linear and exponential weighted principal component analysis techniques based on spectral similarity were employed for the prediction of dye concentration in coloured fabrics, which had been dyed with three component dye mixtures. The matching strategy was based on the equalisation of the first three principal component coordinates of the weighted reflectance curves of the predicted and target sample in a dynamic 3D eigenvector space. The performance of the proposed algorithm was evaluated by the root mean square differences of the reflectance curves and the relative error of the concentration prediction, as well as the metamerism index. The obtained results indicated that the developed exponential weighted principal component analysis method is more accurate than the spectrophotometric method and the simple principal component analysis matching strategy.     

Optimal control of nonlinear frames by Newmark and distributed genetic algorithms

Active control of multi‐storey frame structures with nonlinear hysteretic response has been studied in this paper. A new nonlinear optimal control algorithm based on nonlinear Newmark integration method and distributed genetic algorithm (DGA) has been developed. The objective has been to reduce the response to below any desired level. In this study, DGA has been used to determine the weights in the control law corresponding to displacement, velocity and acceleration. The capabilities of the method has been assessed through simulation where an eight‐storey frame with bilinear hysteretic behaviour has been subjected to a white noise ground acceleration and controlled by the controllers designed by the new algorithm. An active tendon control system comprised of prestressed tendons and either a single actuator, which could apply a force to one of the floors, or eight actuators, which could fully control the frame, has been used. Also, the optimum actuator placement in the single actuator case has been studied. The designed controllers have been tested under both near and far‐field earthquakes and have performed successfully. Copyright © 2009 John Wiley & Sons, Ltd.     

Abrasive Wear Behavior and Its Relation with the Macro-indentation Fracture Toughness of an Fe-Based Super-Hard Hardfacing Deposit

Tribology Letters - There is an ongoing debate concerning the best rheological model for liquid flows in elastohydrodynamic lubrication (EHL). Due to the small contact area and high relative...     

Second modification of a polyamide membrane surface

The aim of this study was to develop the water flux and antifouling properties of a polyamide (PA) nanofiltration membrane. A nascent PA membrane was prepared with an interfacial polymerization technique and modified with 2,5‐diaminobenzene sulfonic acid (2,5‐DABSA) as a second modification. The effects of the 2,5‐DABSA monomer concentration and the modification time on the membrane performance were investigated. The chemical structure, morphology, roughness, hydrophilicity, molecular weight cutoff, and antifouling properties of the membranes were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, atomic force spectroscopy, contact angle measurement, poly(ethylene glycol) tracers, and cetyl trimethyl ammonium bromide filtration, respectively. The PA membrane with optimized performance was shown to have a greater than 44% higher water permeate flux with a change in the salt rejection in the order RNa₂SO₄ > RCaCl₂ > RNaCl to RNa₂SO₄ > RNaCl > RCaCl₂. The improvement of the hydrophilicity led to excellent antifouling properties in the new PA membranes and illustrated a promising and simple method for the fabrication of high‐performance PA membranes. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43583.     

Low Temperature Upper Critical Field Studies in Organic Superconductor β″-(BEDT-TTF)2SF5CH2CF2SO3

Low temperature upper critical field studies have been carried out in a new organic superconductor -(BEDT-TTF) ₂ SF ₅ CH ₂ CF ₂ SO ₃. For field parallel to the superconducting layers, the upper critical field determined from transport measurements exceeds the BCS Pauli limit at low temperatures. The angular dependence of the resistive transition shows that the upper critical field can be best described by a quasi-two-dimensional model with a cusp near the field parallel to the plane direction.     

Designing optimal tuned mass dampers for nonlinear frames by distributed genetic algorithms

In this paper, the capabilities of tuned mass dampers (TMDs) for the mitigation of response of nonlinear frame structures subjected to earthquakes have been studied. To determine the optimal parameters of a TMD, including its mass, stiffness and damping, we developed an optimization algorithm based on the minimization of a performance index, defined as a function of the response of the nonlinear structure to be controlled. Distributed genetic algorithm has been used to solve the optimization problem. For illustration, the method has been applied to the design of a linear TMD for an eight‐story nonlinear shear building with bilinear hysteretic material behavior subjected to earthquake. The results have shown that the method has been successful in determining the TMD parameters to reduce the structure response. The simplicity and desirable convergence behavior of the method have also been two important results of the method. Two performance indices have been defined: (a) the minimization of the maximum drift and (b) the accumulated hysteretic energy. It has also been shown that the efficiency of the TMD has been influenced by the mass ratio of the TMD, the maximum TMD stroke length and the TMD design earthquake. Copyright © 2011 John Wiley & Sons, Ltd.