Comparison of performances of five prospective approaches for the multi-response optimization

The Taguchi method of experimental design is widely used for optimization of process performance. However, this method has been developed to optimize single-response processes. But, in many situations, the engineers are required to determine the process settings that can simultaneously optimize multiple responses. In the recent past, researchers have proposed several systematic procedures for multi-response optimization. Most of these methods use complicated statistical/mathematical models and are, therefore, not easily comprehendible to the engineers who do not have a strong background in mathematics. Only a few methods, e.g. weighted signal-to-noise (WSN) ratio, Grey relational analysis, multiple-response signal-to-noise ratio, VIKOR (VlseKriterijumska Optimizacija I Kompromisno Resenje in Serbian), and weighted principal component methods, use relatively simpler procedures. In this paper, the computational procedures for these five methods are standardized. Three sets of experimental data are analyzed using these standardized procedures and the predicted optimization performances of the five methods are compared. The results show that no method can give better optimization than the WSN method.     

An in-Depth Analysis of the Swelling,Mechanical, Electrical,and Drug Release Properties of Agar–Gelatin Co-Hydrogels

Agar–gelatin-based co-hydrogels were prepared with different compositions of the agar and the gelatin fractions. The intermolecular hydrogen bonding was higher in the co-hydrogels as compared to the gelatin hydrogel. Swelling studies indicated diffusion-mediated swelling. The electrical stability of the co-hydrogels was higher as compared to the gelatin hydrogel. Though the firmness of the co-hydrogels was higher, Weichert model of viscoelasticity indicated that the inherent mechanical stability of the gelatin hydrogel was superior. The release of ciprofloxacin hydrochloride was predominately Fickian diffusion-mediated. In gist, the co-hydrogels can be tried as polymeric constructs for controlled drug delivery applications.     

Control chart pattern recognition using feature-based learning vector quantization

The reported learning vector quantization (LVQ) network-based control chart pattern (CCP) recognizers in literature use raw process data as the input vector and can recognize six basic CCPs only. In this paper, an LVQ network-based CCP recognizer is presented that can recognize eight basic CCPs, using seven extracted shape features from the pattern data as the input vector. The recognition performance of this recognizer is compared with the LVQ network-based recognizer that uses raw process data as the input vector. The results show that the feature-based recognizer results in substantially better recognition performance than the raw data-based recognizer. The confusion matrix reveals that the recognition performance of the feature-based recognizer can be improved further if any feature that is more powerful in discriminating shift and trend pattern can be identified. Comparison of performances of LVQ network-based and multilayer perceptrons (MLP) network-based recognizers (both using extracted features as input vector) reveals that the LVQ network-based recognizer requires much lesser learning time than the MLP network-based recognizer, but results in little inferior recognition performance.     

Improving yarn quality through multi-response optimisation of electronic yarn clearer in winding machine

One of the essential post-spinning operations of yarn is winding. In winding machine, ring yarn (i.e. the yarn produced in ring frame) is passed through electronic yarn clearer (EYC) and wound into empty conical-shaped packages called cones. The purpose of EYC is to improve the yarn quality as much as possible by eliminating the various types of faults or irregularities, e.g. thin places, thick places and neps from the ring yarn. The process engineer in an Indian spinning mill was facing the problem of inaccurate detection of faults by the EYC, which led to higher number of winding breaks as well as yarn irregularities. Aiming to tackle the problem, Taguchi’s L₂₇ orthogonal array experimentation was carried out. The experimental data are analysed using weighted principal component (WPC) method and principal component analysis-based grey relational analysis that take care of correlation among multiple responses. The WPC method is found to give better optimisation. By using the optimal settings, sensitivity of the EYC to detection of faults increased and thus, yarn quality improved substantially.     

Use of carbonitride film as buffer layer for CVD diamond nucleation

Enhanced nucleation of polycrystalline diamond has been achieved on Si(100) with an intermediate layer of carbonitride. The carbonitride film was formed by an ion beam assisted deposition method and was characterized by Rutherford backscattering, X-ray photoelectron and laser Raman spectroscopies. The diamond deposition was accomplished using a hot filament chemical vapor deposition technique. Diamond film quality was examined with the help of laser Raman spectroscopy and scanning electron microscopy.