Analysis of Basis Weight Uniformity Indexes for the Evaluation of Fiber Injection Molded Nonwoven Preforms

Fiber injection molding is an innovative approach for the manufacturing of nonwoven preforms but products currently lack a homogeneous fiber distribution. Based on a mold-integrated monitoring system, the uniformity of the manufactured preforms will be investigated. As no universally accepted definition or method for measuring uniformity is accepted yet, this article aims to find a suitable uniformity index for evaluating fiber injection molded nonwovens. Based on a literature review, different methods are implemented and used to analyze simulated images with given distribution properties, as well as images of real nonwovens. This study showed that quadrant-based methods are suitable for evaluating the basis weight uniformity. It has been found that the indexes are influenced by the number of quadrants. Changes in sample size do not affect the indexes when keeping the quadrant number constant. The quadrants-based calculation of the coefficient of variation showed the best suitability as it shows good robustness and steady index for varying degrees of fiber distribution

Natural Fiber Based Composites

Entitled “Natural Fiber-Based Composites”, this Special Issue has the objective to give an inventory of the latest research in the area of composites reinforced with natural fibers. Fibers of renewable origin have many advantages. They are abundant and cheap, they have a reduced impact on the environment, and they are also independent from fossil resources. Their ability to mechanically reinforce thermoplastic matrices is well known, as their natural heat insulation ability. In the last twenty years, the use of cellulosic and lignocellulosic agricultural by-products for composite applications has been of great interest, especially for reinforcing matrices. The matrices can themselves be of renewable origin (e.g., proteins, starch, polylactic acid, polyhydroxyalkanoates, polyamides, etc.), thus contributing to the development of 100% bio-based composites with a controlled end of life. This Special Issue’s objective is to give an inventory of the latest research in this area of composites reinforced with natural fibers, focusing in particular on the preparation and molding processes of such materials (e.g., extrusion, injection-molding, hot pressing, etc.) and their characterization. It contains one review and nineteen research reports authored by researchers from four continents and sixteen countries, namely, Brazil, China, France, Italy, Japan, Malaysia, Mexico, Pakistan, Poland, Qatar, Serbia, Slovenia, Spain, Sweden, Tunisia, and Vietnam. It provides an update on current research in the field of natural fiber based composite materials. All these contributions will be a source of inspiration for the development of new composites, especially for producers of natural fibers, polymer matrices of renewable origin and composite materials. Generally speaking, these new materials are environmentally friendly and will undoubtedly find numerous applications in the years to come in many sectors. Dr. Philippe Evon Guest Edito

Artificial Neural Networks and Their Applications in the Engineering of Fabrics

WOS: 00036372550000

Thermal protection properties of aerogel-coated Kevlar woven fabrics

This paper investigated the thermal properties of aerogel-coated Kevlar fabrics under both the ambient temperature and high temperature with laser radiation. It is found that the aerogels combined with a Kevlar fabric contribute to a higher thermal insulation value. Under laser radiation with high temperature, the aerogel content plays a vital role on the surface temperature of the fabrics. At laser radiations with pixel time 330 μs, the surface temperatures of the aerogel coated Kevlar fabrics are 400-440°C lower than that of the uncoated fabric. Results also show that the fabric temperature is directly proportional to pixel time. It can be concluded that the Kevlar fabrics coated with silica aerogel provides better thermal protection under high temperature

"Natural Fiber Based Composites", edited by Philippe Evon (Printed Edition of the Special Issue Published in Coatings)

This book is a printed edition of the Special Issue "Natural Fiber Based Composites" that was published in Coatings and edited by Dr. Philippe Evon. Dr. EVON is Research Engineer at the Laboratoire de Chimie Agro-industrielle (LCA). He has the habilitation to supervise researches (HDR). He specializes in the valorization of wastes from biomass to produce extracts and to design agromaterials. He is mainly developing studies for using biomass as raw material for: - Producing bioactive extracts through fractionation processes using “green” solvents and the twin-screw extrusion technology as continuous extraction technique. - The manufacture of agromaterials by combining single- or twin-screw extrusion technologies with molding processes (e.g. injection-molding or thermopressing). He is the Manager of the LCA’s Industrial Technological Hall “AGROMAT” dedicated to agromaterial’s (https://www6.toulouse.inra.fr/lca/AGROMAT), which is located in Tarbes (South-West of France)

Empleo de textiles en aplicaciones de absorción sonora

Tesis por compendio[ES] Esta memoria de tesis presenta una contribución al estudio de los materiales textiles en el campo de la absorción sonora. En concreto, se ha trabajado con la asociación de una capa absorbente fibrosa constituida por una estructura laminar no tejida cuya composición es poliéster y una capa resistiva a base de tejido de calada también compuesta de poliéster. El objetivo de este trabajo consiste en evaluar las variaciones que provocan los cambios en distintos parámetros de construcción de la capa resistiva, sobre el comportamiento del conjunto ante el sonido. Para abordar el problema se emplean distintos tejidos de calada, tales como telas simples, múltiples, acolchadas y rizo, con diferentes parámetros de construcción. Se mide el coeficiente de absorción de sonido al aplicarlas a diferentes espesores de estructura no tejida de poliéster, empleando el tubo de ondas estacionarias. Tras analizar los resultados obtenidos, se observan diferencias en los coeficientes de absorción de sonido alcanzados, las cuales se explican atendiendo al espesor del no tejido, pero también se observa la influencia de las características constructivas de los tejidos empleados. Finalmente, se emplea el diseño de experimentos para obtener la combinación óptima de parámetros que proporciona el mayor coeficiente de absorción de sonido para un tipo de tejido dado en todas las frecuencias estudiadas. Se concluye que, la modificación en la absorción de sonido de una estructura no tejida al aplicar una capa resistiva de tejido de calada, es lo suficientemente significativa como para ser tenida en cuenta a la hora de diseñar productos textiles para acondicionamiento acústico y que el diseño de experimentos constituye una herramienta de gran utilidad a este fin.[CAT] Aquesta memòria de tesi presenta una contribució a l'estudi dels materials tèxtils en el camp de l'absorció sonora. En concret, s'hi ha treballat amb l'associació d'una capa absorbent fibrosa constituïda per un no teixit de polièster i una capa resistiva a base de teixit de calada de composició polièster. L'objectiu d'aquest treball consisteix a avaluar les variacions que provoquen els canvis en diferents paràmetres de construcció de la capa resistiva, sobre el comportament del conjunt davant el so. Per a abordar el problema s'empren diferents teixits de calada, com ara teles simples, múltiples, encoixinats i ris, amb diferents paràmetres de construcció. Es mesura el coeficient d'absorció en aplicarles a diferents grossàries de no teixit de polièster, emprant el tub d'ones estacionàries. S'observen diferències en els coeficients d'absorció de so obtinguts, les quals s'expliquen atenent la grossària del no teixit, però també a les característiques constructives dels teixits emprats. Finalment, s'empra el disseny d'experiments per a obtenir la combinació òptima de paràmetres que proporciona el major coeficient d'absorció de so per a un tipus de teixit donat en totes les freqüències estudiades. Es conclou que la modificació en l'absorció de so d'un no teixit en aplicar una capa resistiva de teixit de calada és prou significativa per a ser tinguda en compte a l'hora de dissenyar productes tèxtils per a condicionament acústic i que el disseny d'experiments constitueix una eina de gran utilitat a aquest efecte.[EN] This thesis report presents a contribution to the study of textile materials in the field of sound absorption. Specifically, we have worked with the association of a fibrous absorbent layer consisting of a polyester nonwoven and a resistive layer based on openwork fabric. The objective of this work is to evaluate the variations that cause the changes in different construction parameters of the resistive layer, on the behaviour of the whole before the sound. To address the problem, different openwork fabrics are used, such as single, multiple, quilted and curl fabrics, with different construction parameters. The absorption coefficient is measured when applied to different thicknesses of polyester nonwoven, using the standing wave tube. Differences are observed in the sound absorption coefficients obtained, which are explained according to the thickness of the nonwoven, but also to the constructive characteristics of the fabrics used. Finally, the design of experiments is used to obtain the optimal combination of parameters that provides the highest sound absorption coefficient for a given type of tissue at all frequencies studied. It is concluded that the modification in the sound absorption of a nonwoven when applying a resistive layer of openwork fabric is significant enough to be taken into account when designing textual products for acoustic conditioning and that the design of experiments constitutes a very useful tool for this purpose.Al departamento de Ingeniería Textil y Papelera y a la unidad docente de Alcoy del departamento de Mecánica de los Medios Continuos y Teoría de Estructuras, por facilitarme los medios necesarios para realizar todas las actividades que han sido necesarias. A Jaime Ramis Soriano, por recibirme en el laboratorio de Grupo de Acústica Aplicada del IUFACyT de la Universidad de Alicante.Segura Alcaraz, MDP. (2020). Empleo de textiles en aplicaciones de absorción sonora [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/159786TESISCompendi

The development of a process for the production of textiles with fully embedded electronics

Many attempts to combine Electronics and Textiles have been realised for many years now. At the beginning with the introduction of conductive wires, then with the introduction of sensors and more complex circuits onto an everyday garment. The next step of evolution of combining these seemingly different fields is to integrate the electronics inside a textile structure, so that it will provide a seamless implementation of both worlds into everyday life. The microelectronics, mechanical, electrical, computing and chemical engineering advances of the last years, can ensure that, nowadays, this is feasible. Because of the minuscule dimensions of the electronic components, so that can be integrated inside the thin-by-nature yarn, and the necessity of a flexible and bendable structure overall, the task required is not of a small scale and has no prerequisite. This Thesis provides the backbone of an innovative technique to achieve the above goal in an automated or semi-automated, accurate, repeatable, reliable and time-cost effective way, combining all the required procedures, outlining the issues and proposing solutions on a plethora of them. This research's outcome, after both manual and automated implementation of the microelectronic component encapsulation concept, proves that automation of the process is feasible with more research and funding in the future. Because this is an innovative and challenging in its implementation, as far as the tiny dimensions of the electronic components are concerned, more testing and physical implementation must be conducted with the contribution of a team of people from different disciplines, in order to finalise it and produce the first linear and continuous version of the machine that can automatically produce electronic yarns, i.e. yarn with electronic components inside its core. The importance of this Thesis is that it sets the foundations, guidelines and requirements for the development of an all-new manufacturing procedure and the creation of a new machine, i.e. the Electronic Yarn Machine -EYM- in the future

Advances in Polymeric Materials for Biomedical Applications

Significant research efforts are currently being undertaken in the field of natural and synthetic polymers for a range of biomedical applications. (Co)polymer molecular structure, topology, self-assemblies, biodegradation, and hydrophobicity are of biomaterial importance for intrinsically biocompatible polymer systems. This book is comprised of nine chapters, published previously as original research contributions of the Special Issue focused on advances in polymeric materials for biomedical applications. The authors of these contributions are predominantly from central European countries, Italy and the United Kingdom. The content of this book will be of interest to scientists, scholars and students working in this area of knowledge, reflecting the progress in the development of advanced natural and synthetic polymer biomaterials