TABLE OF CONTENTS

Volume 5, Issue 2, Summer 2006
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This paper describes different approaches for predicting collection efficiency of nonwoven fibrous filters. Traditionally, the flow field has been obtained by analytically solving the Navier-Stokes equations inside over-simplified geometries with the fibers placed in regular arrays perpendicular to the flow direction. Our approach, on the other hand, is to exploit a numerical method based on the finite-volume technique to solve the flow inside 3-D virtual webs generated based on the properties of real filters. Our results showed a good qualitative agreement with previous works.

KEYWORDS: Permeability; Cell model; CFD; Filtration; Nonwoven.

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ABSTRACT

Initial pressure drop, along with efficiency and capacity, is one of the important performance parameters of a fibrous filter. In moving towards “Analysis-Led Design” of filtration products, a realistic prediction of initial pressure drop based on media physical parameters is a necessary first step.

We will present existing models, such as the 2D Kuwabara and the 3D cellular approach, and discuss their limitations in predicting initial pressure drop of fibrous filter media, which have pushed us towards a numerical modeling (CFD) approach. In order to optimize the inner fiber structure for a specific application, simple and rapid simulations are required. Therefore a 2D approach, which can run on a standard PC workstation, is favored over sophisticated 3D fiber models, running on parallel computers.

As the fiber structure is not truly random, a literature survey of various 2D approaches to model disarrangement or random fiber structures will be presented. However, fully random structures still over-predict the pressure drop by 120 % to 200 %, compared to measurements on some of our important filter media grades. Therefore we will present some of the results of a Technology Development for Six Sigma (TDFSS) project, and our approach of modeling fibrous filters by creating “partial-random” structures. We will illustrate our rapid and highly automated method combining MATLAB and the CFD program FLUENT/GAMBIT to predict realistic initial pressure drop values. The much-improved agreement between CFD predictions and measurements for a wide variety of different filter media will be shown and discussed.

KEYWORDS: Filtration, CFD, 2D Kuwabara, 3D cellular approach

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Air permeability is an important property for wovens and it depends on many parameters of the fabric. Thus, a theoretical determination is highly complex and difficult in relating the parameters to the air permeability. Therefore, establish of the air permeability is usually made experimentally.

In this study, it has been attempted to establish a simple theoretical model for the air permeability of woven fabrics. For the purpose, a capillary model of porous systems on D’Arcy’s law was used, and theoretical values were investigated.

Keywords: Air permeability, woven, fabric structure, warp and weft yarn

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KEYWORDS: Viscose, sulphur, sulphur analysis, sulphur scale, finishing

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A new dynamic fatigue tester simulating knitted fabric deformation during use is proposed in this paper. An image processing device was developed and used to model the loop geometry of a plain knitted fabric. Based on the analysis of existing plain knitted fabrics, the geometrical modelling of knitted loop propose the combination of different mathematical functions to describe the loop geometry. A plain knitted fabric made of cotton commonly used in the clothing industry was tested with the fatigue device at different cycles and then relaxed. Repeated elongation involved permanent deformation depending on relaxation and number of cycles. The origins of dimensional behaviour of knitted fabric after fatigue test were discussed.

KEYWORDS: fatigue test, plain knitted fabric, image processing, permanent deformation, relaxation

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Cotton trash is known to affect textile-processing efficiency. Removal of cotton trash is a means to improve textile spinning. To combat trash and efficiency problems, textile mills frequently specify that cotton bales, which they acquire, should be no higher than a 3 leaf for processing on Murata Airjet Spinner (MJS) or Murata Vortex Spinner (MVS) equipment. This leaf grade cut-off point is based on past spinning experiences, which point toward processing problems during weaving and excessive loom stops. This research evaluates how High Volume Instrument (HVI™) Trashmeter software analyzes cotton trash and its particle size distribution in a 40-bale textile mill laydown. This study compared the distribution of particles within all bales and how similar these bales were to one another and HVI™ properties throughout the bales. Bales of known and constant leaf grade appear to have different trash particle size distributions. Further work is needed to determine if trash particle distributions provide sufficient information for the measurement of cotton trash in high-speed textile spinning.

KEYWORDS: Cotton, trash, bales, quality, High Volume Instrument, textile industry, fiber testing

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This work aimed to use of chicken feathers wastes (CF) as a natural source of active amino acids after alkali treatments with 0.95N NaOH solution. The soluble feather was analyzed by the liquid chromatography and applied to both the mercerized and bleached cotton fabrics from cotton varieties namely Giza 89 (G89), and Giza 90 (G90) of crop season 2002/2003. The treated and untreated fabric samples were tested for their mechanical properties expressed as the tensile strength N/cm2, and elongation%. The dyeing behavior expressed as color strength (K/S) using Kubelka-Munk equation, and UV protection values were also investigated. The fixation of CF on the cotton fabric was done by the padding of CF solution onto fabrics followed by dry-cure process. The factors affecting the fixation processes were systematically studied. The finished fabrics show sufficient whiteness, high tensile strength, more dyeing uptake, and more reduction of the UV transmitted as compared to the untreated samples.

KEYWORDS: Egyptian cotton, chicken feathers, feather waste

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Cationization of cotton is emerging as an effective tool that solves the environmental problems associated with dyeing of cotton with anionic dyes.

In this research work, the cationizing efficiency of cationizing agent CIBAFIX WFF was estimated and it was found to be a better one than compared with normal or existing method of reactive dyeing of cotton. The influence of process conditions like concentration of cationizing agent, concentration of alkali and temperature of cationization bath on the color strength (K/S) and Total dye utilization percentage (T%) were analyzed and these process conditions are optimized. The optimized process conditions gives better K/S values and T% than the normal reactive dyeing of cotton.

The effect of cationization on color strength and color fastness of various reactive dyes was found and cationization shows higher increase in lighter shades and lesser increase in dark shades than normal cotton dyeing. The impact on the environmental pollution and the dyed fabric quality were ascertained and compared with the existing dyeing system and the cationized cotton gives very less (nearly zero) environmental pollution. The cationized cotton shows similar kind of fabric quality as like normal dyeing of cotton.

Cationization of cotton with cibafix WFF was found to be a successful and commercially viable process, since it is found to be cheaper than the normal dyeing process.

KEYWORDS: Cationization, Cotton, Reactive Dyes, Cibafix WFF, Color Strength, % Exhaustion

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This study examined important environmental factors influencing the cotton export performance in the current top ten countries supplying cotton products to the United States, including Mexico, China, India, Honduras, Pakistan, Bangladesh, Dominican Republic, El Salvador, Indonesia, and Guatemala, using Austin’s (1990) Environmental Analysis Framework (EAF). The research used secondary data collected from various government sources with a 26 year time period from 1974 to 2000. The results indicated that three variables, GNP, Exchange Rates, and Roads, have significant positive impact on U.S. cotton import dollar volume, while Tariff Rates have significant negative impacts on U.S. cotton import dollar volume. The findings have important managerial implications to U.S. cotton importers and retailers, and for the ten cotton-exporting countries.

KEYWORDS: Cotton, international trade, Environmental Analysis Framework, import, export, competitive advantage, GNP, exchange rate, labor cost, roads, merchant marine, tariff rate, quota

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Textile and Apparel Supply Chain Management Technology Adoption

The Burlington Industries Case and Beyond

Dr. W. Douglas Cooper
Belk College of Business Administration
UNC Charlotte

ABSTRACT

The term supply chain management first appeared in the literature in 1982 with credit to Oliver and Webber (12). However, it can be argued that modern supply chain management began in the mid 1960s with the marriage of some basic, best-practice concepts of production-distribution processes and the 3rd generation of IBM computers; S/360 systems. One of the chief players in the early development of supply chain design and management philosophy was a textile and apparel company; Burlington Industries.

Much of the accumulated knowledge about textile and apparel firm contribution in this area has been lost or forgotten with the fall of the US domestic giants of the 1970s and 80s. Thus, the purpose of this paper is to establish a historical document that points to the important role that was played by the firm to the supply chain body of knowledge before the formal development of the “supply chain” term in the 1980s and 90s. It is the author’s belief that an understanding the early work in developing large vertically integrated supply chain designs and strategies for textile and apparel firms can give the reader significant insight into global textile and apparel supply chain designs of the future.

A case study involving Burlington Industries and the supply chain information system enabler of the time, IBM, that is not to be found in the academic literature, is chosen as the core of the paper. The paper draws on the development and adoption of a supply chain management strategy for its separate businesses that was an important part of a massive 10-year, $2 billion (1975-85 dollars) capital expenditure program that was launched by Burlington Industries in 1975; a project scope unprecedented in the history of the world’s textile industry.

KEYWORDS: Supply chain, database designs, client-server information systems, ERP, MRP global economy, IBM, information technology, employment, Wal-Mart

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