Studies on the Reduction of Coefficient of Variation: A Case Study

In a spinning mill, yarn is the final product. Linear density expressed in terms of count is one of the important characteristics of yarn. Because variability of textile strands increases as the linear density increases, the variability in the count is often measured in terms of coefficient of variation (CV)%. The yarn with a high CV% of count leads to a higher end breakage rate during the spinning and subsequent weaving/knitting operations, and consequently, results in lesser productivity and poorer appearance quality of the woven/knitted fabric. When this woven/knitted fabric is dyed, uneven shades are generated. Because the production of yarn involves processing of raw cotton in multimachines at multistages, possible sources that lead to a high CV% of count are many. Enrick's (1960) analysis procedure, which is based on the modification of the range method for analysis of variance, is used conventionally for detecting the stages where excessive “between-machine” differences are present. When the CV% of count is inflated due to the generation of systematic variation in any machine or introduction of high variability by any machine, this inflation remains undetected when using Enrick's procedure. The case study presented here demonstrates that a step-by-step analysis of linear densities of different stage-outputs starting from yarn to card sliver, using appropriate nested design models along with Duncan's multiple range test, is very useful in detecting all possible sources of a high CV% of count of yarn.     

Retailers' tagging practices: a potential liability?

This study investigates the coverage of federally mandated information on over‐the‐counter (OTC) drug labels by electronic article surveillance (EAS) tags applied to the exterior of cartons. Using adult‐strength analgesics containing acetaminophen as a case study, researchers investigated the issue in Houston, Texas (24 stores) and Lansing, Michigan (33 stores). The information obscured by EAS tags was identified and classified for a total of 849 packages using a standardized data collection instrument. The results indicated that 293 packages examined, or 34.5%, had information mandated by the US Food and Drug Administration (US FDA) fully or partially obscured by the EAS tags. Retailers and manufacturers should be aware of such practices to reduce potential liability. Recommendations for improving EAS tag usage on OTC products are presented. Copyright © 2004 John Wiley & Sons, Ltd.     

Analysis of indoor particles and gases and their evolution with natural ventilation

The air composition and reactivity from outdoor and indoor mixing field campaign was conducted to investigate the impacts of natural ventilation (ie, window opening and closing) on indoor air quality. In this study, a thermal desorption aerosol gas chromatograph (TAG) obtained measurements of indoor particle‐ and gas‐phase semi‐ and intermediately volatile organic compounds both inside and outside a single‐family test home. Together with measurements from a suite of instruments, we use TAG data to evaluate changes in indoor particles and gases at three natural ventilation periods. Positive matrix factorization was performed on TAG and adsorbent tube data to explore five distinct chemical and physical processes occurring in the indoor environment. Outdoor‐to‐indoor transport is observed for sulfate, isoprene epoxydiols, polycyclic aromatic hydrocarbons, and heavy alkanes. Dilution of indoor species is observed for volatile, non‐reactive species including methylcyclohexane and decamethylcyclopentasiloxane. Window opening drives enhanced emissions of semi‐ and intermediately volatile species including TXIB, DEET, diethyl phthalate, and carvone from indoor surfaces. Formation via enhanced oxidation was observed for nonanal and 2‐decanone when outdoor oxidants entered the home. Finally, oxidative depletion of gas‐phase terpenes (eg, limonene and α‐pinene) was anticipated but not observed due to limited measurement resolution and dynamically changing conditions.     

Chemical Signals of Synthetic Disaccharide Derivatives Dominate Rhamnolipids at Controlling Multiple Bacterial Activities

Microbes secrete molecules that modify their environment. Here, we demonstrate a class of synthetic disaccharide derivatives (DSDs) that mimics and dominates the activity of naturally secreted rhamnolipids by Pseudomonas aeruginosa. The DSDs exhibit the dual function of activating and inhibiting the swarming motility through a concentration‐dependent activity reversal that is characteristic of signaling molecules. Whereas DSDs tethered with a saturated farnesyl group exhibit inhibition of both biofilm formation and swarming motility, with higher activities than rhamnolipids, a saturated farnesyl tethered with a sulfonate group only inhibits swarming motility but promote biofilm formation. These results identified important structural elements for controlling swarming motility, biofilm formation, and bacterial adhesion and suggest an effective chemical approach to control intertwined signaling processes that are important for biofilm formation and motilities.     

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.     

CSCC for the mean and standard deviation of non-normally distributed life test data

In this paper Cumulative Sum Control Charts (CSCC) have been constructed for the mean and standard deviation of non-normally distributed life test data. The parameters of the V-mask have been determined and finally the expression for the Average Run Length is derived.     

Physicochemical,thermal and pasting properties of starch separated from γ-irradiated and stored potatoes

The morphological, thermal and pasting properties of starch separated from potatoes of three varieties (Kufri Chandramukhi, Kufri Jyoti and Kufri Chipsona-2), treated either with CIPC (isopropyl N-(3 chlorophenyl) carbamate) or γ-irradiation (Co⁶⁰, 0.1 and 0.5 kGy) and subsequently stored at 8, 12 and 16 °C for 90 days, were studied. Scanning electron microscopy (SEM) showed the presence of oval and irregular shaped starch granules with a diameter range of 15–16 μm. Mean granule size of starch separated from potatoes stored at 12 °C ranged from 18–25 μm and irradiation treatment resulted in an increase in the proportion of small size granules. The irradiation of potatoes with 0.5 kGy resulted in starch with significantly lower peak-, trough- and breakdown-viscosity as compared to starch from potatoes treated with either CIPC or 0.1 kGy irradiation. The irradiation of potatoes with 0.5 kGy caused a significant increase in setback and pasting temperature. Pasting temperature of starch was observed to vary with the storage temperature. Starch separated from potatoes stored at higher temperature showed lower pasting temperature and vice versa. The starch from potatoes stored at 8 °C showed higher peak-, trough- and breakdown-viscosity and lower setback. Peak viscosity increased and swelling volume decreased with increase in storage temperature. FTIR spectra showed that the starch from irradiated potatoes displayed a significant decrease in the intensity of the C–H stretch region between 2800 and 3000 cm⁻¹, which was observed to be irradiation dose-dependent, and higher with 0.5 than 0.1 kGy. However, a slight broadening of O–H stretch (3000–3600 cm⁻¹) in starches from irradiated potatoes was observed. The spectral changes caused by γ-irradiation were apparent in the O–H stretch (3000–3600 cm⁻¹), C–H stretch (2800–3000 cm⁻¹) and bending mode of water (1600–1800 cm⁻¹).     

Heat and mass transport performance of MHD elastico-viscous fluid flow over a vertically oriented magnetized surface with magnetic and thermo diffusions

The key objective in this study is to examine the heat and mass transport behavior of magnetohydrodynamic elastic-viscous fluid flow over a vertically oriented magnetized surface placed in a uniform permeable regime with magnetic and thermo diffusions. The fluid is partially ionized and permeated to flow in the presence of a strong magnetic field domain. Hence the Hall current effect is considered in this investigation. The significance of rotation and induced magnetic field on the flowing nature are also scrutinized in this study. The mathematical model of the problem is converted to a similar model by introducing suitable nondimensional variables. To obtain the closed-form solutions of the flow leading equations, the regular perturbation analysis is utilized. For the exhibition of results, figures and tables are generated with the assistance of scientific computation software MATHEMATICA. Computed results are validated with the existing result in the limiting case. Such an investigation is important in evaluating the flow characteristics of low magnetic diffusive viscoelastic fluid. A noteworthy result seen is that magnetic diffusion significantly controls the fluid flow by altering the magnetic drag force. Mass diffusion factor brings an increase in the fluid velocity. Furthermore, we observed that the surface current density along the principal flow direction is significantly reduced by magnetic diffusion and mass diffusion factor.     

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.     

Deformation and stored energy of polycrystalline bismuth

Stress-strain curves of polycrystalline bismuth deformed in compression were obtained at 78, 193, 243, 273, 298 and 353 K at strain rates of 2.2 × 10^-4, 2.2 × 10^-3 and 2.2 × 10^-2 s^-1. The strain rate sensitivity was measured by strain rate change tests. Activation volumes and activation enthalpies of deformation were determined. The stored energy of cold work was measured by liquid metal solution calorimetry. The flow stress shows a large strain rate dependence except at 78 K; its strain rate sensitivity goes through a maximum in the range of 243 to 273 K. The interpretation of the activation volume and activation enthalpy suggests that the deformation mechanism changes between 193 and 243 K and between 298 and 353 K. The stored energy of cold work increases at first linearly with strain and at a strain of approximately 0.5 levels off to a saturation value of about 420 J .g-atom^-1. The stored energy and the ratio of the stored to the expended energy are unusually large. Some conclusions are drawn regard-ing the deformation mechanism of bismuth.