A model of seam pucker and its applications Part I: theoretical

Abstract

This article considers a simple model of the lock stitch (301) seam, and uses it to derive a measure of the severity of puckering in the seam. The numerical value of the measure depends on the bending properties of the fabrics and thread in the seam, together with the tensions in the threads. How the latter may be estimated is discussed.     

Investigation of Seam Pucker in Lightweight Synthetic Fabrics as an Aesthetic Property Part I: A Cognitive Model for the Measurement of Seam Pucker

Seam pucker is an area which is now receiving particular attention especially with the development of microfibre fabrics which are inherently prone to deformations during garment manufacture. Although fabric properties can be related to seam pucker, the aesthetic judgement is still left to subjective assessment which is based upon ranking the stitched fabric samples by judges having compared them with photographic ‘standards’. The shortcomings of this procedure are obvious; judges do not always agree, they need to be trained, the procedure is time consuming and non standardised. This paper reports upon the development of a new measuring procedure which is based on the use of a computer and a camera, ie computer ‘vision’. This procedure is objective and is focused on the aesthetic property of the seam assembly, by ‘modelling’ the cognitive process involved in seam pucker assessment The results are organised in two parts: Part I reports on the development of a cognitive ‘model’ for the measurement of seam pucker and Part II on the model implementation using the computer ‘vision’ system.     

动态投入产出模型及其应用

研究了一类考虑到科技进步的投入产出模型及其在制定国民经济发展规则中的应用。     

Thermal Properties of Amylose and Its Derivatives. Part II

The effect of nature of substituent groups on the stability and mode of decomposition of amylose derivatives has been studied. Kinetics of decomposition of amylose phenyl acetate, amylose tosylate and amylose phthalate have been investigated using the thermogravimetry (TG) and differential thermal analysis (DTA) in nitrogen atmosphere. TG data are analyzed using the methods of Chatterjee, and Anderson and Freeman while DTA data are analysed using the method of Reich. TG thermograms of all the amylose derivatives studied show the characteristic sigmoidal curves and the evaluation of kinetic parameters from them indicates that the major decomposition reaction follows almost first order kinetics. The nature of substituent groups in amylose derivatives plays an important role on the stability and following order of stability has been noted: amylose palmitate > amylose acetate > amylose propionate > amylose phenylacetate > amylose benzoate > amylose > NaCMA > amylose succinate > amylose phthalate > amylose tosylate.     

The Objective Assessment of Fabric Pilling. Part II: Experimental Work

The paper presents the results of pilling assessments of fifty knitted fabrics by the application of the laser triangulation technique. It also compares the results with the corresponding values given by a panel of judges.     

The Automatic Control of Card-web Linear Density. Part II: Experimental Verification of Short-term Control

A controller based on the use of error signals, taken from measurement of web density on both the doffer and cylinder of a cotton card, to control the speed of the doffer was assessed for its ability to control the short-, medium-, and long-term irregularity of the web linear density at output from the card. It is shown that, on a modern high speed card, the system can control the irregularity down to 25-cm wavelengths.     

Some Textile Applications of Finite-element Analysis Part II: Finite Elements for Yarn Mechanics

The concepts of modal decomposition developed in an earlier paper are used to produce a three-dimensional element for aligned fibre assemblies. The element degrees of freedom are introduced and the chosen mode shapes of the element demonstrated. The finite element is tested by using simple material-property assumptions, and the element is verified against a theoretical model of the twisting of a single fibre about a solid core. The element is then verified qualitatively by modelling realistic yarn situations, and the resultant deformation plots are presented.     

Dry Peeling of Tomato by Infrared Radiative Heating: Part II. Model Validation and Sensitivity Analysis

In an accompanying study, a predictive mathematical model was developed to simulate heat transfer in a tomato undergoing double sided infrared (IR) heating in a dry-peeling process. The aims of the present study were to validate the developed model using experimental data and to investigate different engineering parameters that most strongly influence the rate and uniformity of IR heating. The mode was verified by comparison of the predicted temperature profiles with experimental data for tomatoes with three dimensions. Uniformity of temperature distribution at tomato surface was quantified by surface-averaged temperatures and a derived temperature uniformity index. The predicted temperatures agreed well with experimental data (r ²?>?0.9). Simulation results illustrated that IR heating induced a dramatic temperature increase on the tomato surface, which extended to 0.6 mm beneath (>90 °C) during a 60-s heating period, whereas interior temperature at the tomato center remained low (<30 °C). Sensitivity analysis suggested that strategies to enhance IR heating rate and uniformity can be implemented through varying emissive power, adjusting the distance between emitters, and presorting tomatoes according to size. The validated model provides an effective design tool for better understanding the complex IR radiation heating in developing the innovative IR dry-peeling process.     

Synthesis and Applications of Reactive Carbohydrates Part II: Graft Polymerization of Starch and Hydrolyzed Starches with Acrylamide

Starch and different hydrolyzed starch samples were subjected to two independent reactions, namely, grafting with acrylamide using K₂S₂O₈ as initiator and oxidation with K₂S₂O₈ under the grafting condition but in absence of the monomer. Copper number and carboxylic group measurements showed that both grafting and oxidation decrease outstandingly the copper number of the hydrolyzed samples and diminish completely the copper number of the original starch sample. On the contrary, grafting and oxidation cause significant enhancement in the carboxylic content, indicating partial conversion of the aldehydic to carboxylic groups under the oxidative action of K₂S₂O₈; but it is certain that higher amounts of carboxylic groups are created in absence than in presence of acrylamide. Polymerization studies showed that the hydrolyzed starch samples are much more susceptible than the original starch sample toward grafting with acrylamide only during the initial stages of the reaction. Preliminary experiments describing introduction of methylol groups into the molecular structure of grafted sample and application of the methylolated product to cotton fabric were also reported.     

A Review of Hydrophobic Nanocellulose and Its Applications

Nanocellulose is of great interest in various areas nowadays as a natural nanostructured biomaterial. However, in many applications, the high hydrophilicity due to a large number of hydroxyl groups is not desired. The hydrophobic modification of nanocellulose can thus increase its application. This work reviewed recent developments of methods for nanocellulose hydrophobic modification, through physical adsorption and chemical grafting. The applications of hydrophobic nanocellulose were also reviewed.     

Alcoxymethyl Ethers of Glucose and Its Oligomers Part II. Composition and Structure of Alcoxymethyl Glucose Ethers

Dodecoxymethyl glucose ethers were separated by TLC and column chromatography and the main components were identified. The fraction of monododecoxymethyl glucose ethers was separated into positional isomers. The reactivity of hydroxyl groups of glucose in the reaction with dodecoxymethyl chloride was investigated.     

A Study of the United Kingdom Textile Cycle. Part II: Modelling the Cycle

Some evidence is presented which suggests that the relationship between time series representing activities in different parts of the textile industry and in the economy is not deterministic. Box/Jenkins Modelling of nineteen different series shows remarkable similarities between the models. A general model is suggested, which could be used to generate demand input for a capacity-planning simulation model.     

Compression of gellan gels. Part II: Effect of sugars

The effect of sucrose, glucose, fructose and their mixtures on the gelation of 0.5 wt% low acyl gellan in the presence of potassium chloride (100 mM) was investigated by large deformation compression experiments. The sugar concentration varied from 0 to 15 wt% whereas all their combinations at a final concentration of 15 wt% were also studied. Stress at failure and strain at failure along with Young's modulus were calculated from each compression curve. Samples prior to compression were refrigerated at 5 °C for 1, 2 and 24 h. Glucose showed no contribution to the gellan network strength but decreased the firmness of the gels. On the other hand, fructose and sucrose enhanced the strength of the network, with sucrose being slightly more effective, but had no effect on firmness. This behaviour depended solely on the presence of each sugar and not in their concentration. The elasticity of the gels was not significantly altered by the addition of sugars or their mixtures. Strength and firmness shared similar profiles when mixtures of sugars were used to promote gelation. Sugars, when in mixtures, showed no synergistic interactions whereas their type seems to affect the properties of the resulting gels.     

Gas concentration in the interstitial atmosphere of a wheat silo-bag. Part II: Model sensitivity and effect of grain storage conditions

A lumped capacitance model was applied to simulate the change in gas concentration in a wheat silo-bag. The sensitivity of the solution to a given model respiration rate and permeability (degree of gas-tightness of the silo-bag) was examined. Results showed that gas concentration is more sensitive to changes in respiration rate than to permeability of the plastic film. Considerable changes occur in gas concentration in a damaged silo-bag. The definition of an effective permeability to account for gas transfer through holes and plastic film allowed the examination of the effect of different holes configurations (number and size of perforations) on the evolution of gas concentration.The influence of grain storage conditions on the evolution of gas concentration was investigated. The model was run for initial grain temperatures of 20, 25, 30 and 40C and MC in the range (12–16% w.b) and climatic conditions of the South East of Buenos Aires province, Argentina.When dry grain (12–13% w.b) is stored, O₂ level remained above 12% and CO₂ level below 7%. For wet grain (15–16% w.b), CO₂ level was in the range 14–16% after six month storage. The simulations showed that for wet grain anaerobic conditions may be achieved within two weeks to three months of storage, depending on the grain initial temperature. Estimated mean DML for all the storage conditions remained always below 0.04%, the critical limit for safe storage of wheat that will be used for seeds.     

Studies on Sweet Potatoes. Part II: Isolation and Characterization of Starch

By differential sedimentation and centrifugation steps four starch isolates were recovered from sun dried sweet potato flour. The granules in these isolates were of different size, shape and population characteristics, and were anionic in nature. They showed a single stage swelling with 30 to 35% solubility in water and only ∼30% solubility in DMSO even after 72h. Their starch content varied from ∼48 to 88%. The presence of thermostable amylases in sweet potato resulted in considerable decrease in Brabender viscosity values as amylographic studies in the presence of H_gCl₂ showed significant increase in peak (PV) and setback (SBV) viscosities. The starch isolate I had 25% higher PV as compared to the isolate II but retrogradation was much low in this. Susceptibility to glucoamylase digestion showed a decreasing trend from the isolate I to the IV on solid basis, but comparable on starch basis.     

A basis for estimation of consumption: literature values for selected food volatiles. Part II

In this paper we present a compilation of quantitative literature data on volatile compounds in 15 food items including some brandies, meats, oils as well as vegetables, vinegar and potatoes. Levels of the volatile compounds identified (approximately 900) in this group of food items are generally in the ppm range. Carboxylic acids were present in much higher levels in plum brandy, vinegar, lamb and mutton (heated), whereas alcohols, esters and carbonyls aldehydes are particularly abundant in brandy.     

Packing of micro-porous yarns. Part II: optimization of fabric characteristics

This paper is concerned with the study of the characteristics of plain woven fabric produced with micro-porous cotton yarns in weft. The micro-porous yarns with varying packing densities and level of pore volumes are produced by changing proportion of PVA fibre content in the blend, yarn twist multiplier (TM) and spindle speed at ring frame. The micro-pores within the structure of the yarn have been created by dissolving the PVA fibres using washing treatment in hot water. A three-variable factorial design technique proposed by Box and Behnken has been used to study the interaction effects of these variables on the characteristics of fabrics. The influence of these three variables on the mechanical, handle and comfort properties of fabrics are studied, the response-surface equations for all the properties have been derived and the design variables are optimized for various fabric properties. Improvements in bending resistance, abrasion resistance and compressional characteristics have been observed with incorporation of micro-pores within the yarn structure. These fabrics with micro-pores have improved thermal resistance and moisture vapour transmission compared to that of 100% cotton fabric.     

A review on synthesis and characterization of commercially available natural fibers: Part II

Increasing environmental concerns, along with the potential declination of the crude worldwide reserves, have made the human beings to utilize more regenerable resources to substitute for the design and development of more new products. This has made us to use the synthetic and natural fibers to develop innovative products. However, more eco-friendly properties of natural fibers have made them to be preferable over the synthetic fibers. To make efficient use of these fibers, it is essential to know the behavioral characteristics of these fibers. So, in this review II paper, an effort has been made to discuss the various characterization analysis studies, like Fourier transform-infrared spectra spectral analysis, X-ray and thermogravimetric methods carried out by various researchers.