scholarly journals Auxetic Yarn: Fundamentals, Influencing Parameters, Application Areas and Challenges

2021 ◽  
Author(s):  
Md. Khalilur Rahman Khan ◽  
◽  
Abu Bakr Siddique ◽  
Hosne Ara Begum ◽  
◽  
...  
Keyword(s):  
Processing Parameters ◽  
Potential Candidate ◽  
Exciting Field ◽  
Technical Textiles ◽  
Medical Textiles ◽  
Auxetic Materials ◽  
Helical Angle ◽  
Conventional Spinning ◽  
Production Techniques ◽  
Core Yarn

The mechanical behaviour of auxetic materials and structures is the most distinctive characteristic, which differs from that of conventional engineering materials due to the negative Poisson’s ratio. Auxetic materials have the fascinating feature of widening when stretched and contracting when compressed. In recent times, the research of auxetic materials based on textile structures has received a lot of interest. Auxetic effect development at the yarn phase is a new and exciting field of study. Many researchers already developed different types of auxetic yarns, such as the helical auxetic yarn, the plied auxetic yarn, the semi-auxetic yarn etc. The helical auxetic yarn (HAY) is the most commonly mentioned auxetic yarn. It is made up of a rigid wrap and an elastic core yarn. However, it is interesting that auxetic yarns can be produced from conventional non-auxetic fibres through the conventional spinning system as well. The helical auxetic yarn is a new type of yarn with a wide variety of possible applications. Moreover, pore-opening characteristics of auxetic yarns make it a potential candidate in the fields of technical textiles, such as medical textiles, filter application, protective textiles etc. Fabrication of auxetic textiles by utilizing auxetic yarns through simple weaving and knitting technology opens the door to new applications. The aim of this paper is to address the fundamentals of auxetic yarns, such as structure, shortcomings, production techniques, as well as the influencing process parameters. From various research works, it is evident that the wrap helical angle, the core/wrap diameter ratio, and the initial moduli of wrap component are the most vital processing parameters during the production of auxetic yarns. Finally, some potential application areas and challenges of auxetic yarns are also addressed briefly in this paper.

scholarly journals Overview and perspective of nonwoven agrotextile

2019 ◽  
Vol 2 (1) ◽  
pp. 32-45 ◽  
Author(s):  
Paula Marasović ◽  
Dragana Kopitar
Keyword(s):  
Thermal Protection ◽  
Environmental Concern ◽  
Cost Effective ◽  
Weather Conditions ◽  
Natural Fibre ◽  
Potential Candidate ◽  
Food Quantity ◽  
Technical Textiles ◽  
The World ◽  
Agricultural Applications

Agrotextile belongs to one of the twelve sectors of technical textiles covering textile products with application in agriculture, horticulture, cattle breeding and aquaculture as well in agro engineering. The significance of agrotextiles can be stated substantial all over the world since it has been proven to be very versatile and cost effective materials. Nonwoven agrotextiles are innovative products with special structural performances designed for agricultural applications and practices such as weed control, wind protection, frost cover fabric that is used for adjustment of weather conditions from the sudden changing of temperature and seasonal changes. Furthermore, common application of nonwoven agrotextiles are for reducing the sun radiation as well as thermal protection of plants as shade cloth, furthermore for preventing insect and other pests on crops, preventing soil drainage and sediment creation. All over the world, applications of nonwoven agrotextiles products in agriculture have shown great positive impacts on growth, production and protection of various crops and vegetables. Many studies have been proving that nonwoven agrotextile covers accelerate the growth and development of seedlings as well as their nutritive values. By preventing weed growth and insect protection, the use of herbicides and pesticides are reduced. Agrotextiles made of natural fibres can be considered as a potential candidate for replacing some of today’s popular synthetic agrotextiles which are becoming ecologically less acceptable nowadays. Usage of agrotextiles is one of the growing alternatives in today’s context with respect to the increase in global population thus food quantity and food quality and in the same time growing environmental concern. Sustainable socio-economic development considers natural fibre usage in agrotextile production in all possible areas covered by agrotextile application. The main purpose of the review is to give an overview and importance of nonwoven agrotextiles with indication of nonwoven agrotextile perspective in future.

Effect of process variables on the properties of dual-core yarns containing wool/elastane

2018 ◽  
Vol 69 (05) ◽  
pp. 352-356 ◽  
Author(s):  
TURKSOY HUSEYIN GAZI ◽  
YILDIRIM NIDA
Keyword(s):  
Effective Parameter ◽  
Ring Spinning ◽  
Customer Base ◽  
Alternative Materials ◽  
Production Techniques ◽  
Core Components ◽  
Denim Fabric ◽  
Twist Level ◽  
Core Yarn ◽  
Dual Core

The denim, having a large customer base irrelevant of age, gender and social status limitation, has been one of the most important products for thegarment sector. Denim fabric demand has diversified with the changing consumer’s sense of life day by day. The denim manufacturers develop alternative production techniques and materials by turning towards new researches in order to adapt to consumer demands. One of the alternative materials, which are used in denim fabric structure, is the dual-core yarns. The dual-core yarn is manufactured through the modified ring-spinning machine in order to benefit at the same time from the properties of two core components. In this study the influence of some production parameters such as twist level, wool draft and elastane draft on the properties of dual-core yarns containing wool/elastane is investigated.The results indicated that the twist level is significantly effective parameter for the unevenness, hairiness, tenacity and elongation values of dual-core yarns. In addition, wool draft is significantly effective parameter for hairiness and breaking elongation values. It was also observed that variation of elastane draft level affects tenacity and elongation values of dual-core yarns.

scholarly journals Innovation in 3D Braiding Technology and Its Applications

Textiles ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 185-205
Author(s):  
Caroline Emonts ◽  
Niels Grigat ◽  
Felix Merkord ◽  
Ben Vollbrecht ◽  
Akram Idrissi ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Two Dimensional ◽  
Tubular Structures ◽  
Process Step ◽  
Technical Textiles ◽  
Medical Textiles ◽  
Hexagonal Arrangement ◽  
Additional Process ◽  
Near Net Shape ◽  
High Degree

Braids are generally divided into 2D braids and 3D braids. Two-dimensional braids include flat braids and circular braids. Circular braids represent three-dimensional textiles, as they enclose a volume, but consist of a two-dimensional yarn architecture. Three-dimensional braids are defined by a three-dimensional yarn architecture. Historically, 3D braids were produced on row and column braiding machines with Cartesian or radial machine beds, by bobbin movements around inlay yarns. Three-dimensional rotary braiding machines allow a more flexible braiding process, as the bobbins are moved via individually controlled horn gears and switches. Both braiding machines at the Institut für Textiltechnik (ITA) of RWTH Aachen University, Germany, are based on the principal of 3D rotary machines. The fully digitized 3D braiding machine with an Industry 4.0 standard enables the near-net-shape production of three-dimensionally braided textile preforms for lightweight applications. The preforms can be specifically reinforced in all three spatial directions according to the application. Complex 3D structures can be produced in just one process step due to the high degree of design freedom. The 3D hexagonal braiding technology is used in the field of medical textiles. The special shape of the horn gears and their hexagonal arrangement provides the densest packing of the bobbins on the machine bed. In addition, the lace braiding mechanism allows two bobbins to occupy the position between two horn gears, maximizing the number of bobbins. One of the main applications is the near-net-shape production of tubular structures, such as complex stent structures. Three-dimensional braiding offers many advantages compared to 2D braiding, e.g., production of complex three-dimensional geometries in one process step, connection of braided layers, production of cross-section changes and ramifications, and local reinforcement of technical textiles without additional process steps. In the following review, the latest developments in 3D braiding, the machine development of 3D braiding machines, as well as software and simulation developments are presented. In addition, various applications in the fields of lightweight construction and medical textiles are introduced.

Models for basic warp knitted fabrics Part II: single guide bar fabrics (closed-lap and open-lap)

2018 ◽  
Vol 89 (10) ◽  
pp. 1886-1916 ◽  
Author(s):  
Arif Kurbak
Keyword(s):  
Two Dimensions ◽  
Present Series ◽  
Plane Model ◽  
Knitted Fabrics ◽  
Real Samples ◽  
Cubic Curves ◽  
Technical Textiles ◽  
Medical Textiles ◽  
Special Cases

Warp knitted fabrics are mainly used as household goods, technical textiles, medical textiles, etc. Modeling of these fabrics is necessary for predicting the desired technical or medical functions beforehand. In this context, the present series of papers is devoted to the modeling of basic warp knitted fabrics. In this, Part II of this series, models for single guide bar fabrics are created. There are mainly two types of single bar fabrics, namely closed-lap and open-lap single bar fabrics. Structures are also changed by having different lapping movements up to the five needle spaces. In this work, 1 and 1, 2 and 1, 3 and 1, 4 and 1 closed-lap and 1 and 1, 2 and 1, 3 and 1 open-lap single bar warp knitted fabrics are considered. During modeling, the loop leanings in the course-wise direction are considered, curvature equalities at the loop parts are attained as much as possible, two connected parabolas are taken as the fabric plane model of the loop connection part, loop heads are taken as parametric ellipses in two dimensions and the remaining loop parts are modeled by wrapping parabolic or cubic curves on imaginary cylindrical or conical objects. The models created are versatile and they can be changed and used for special cases. The models created are drawn to scale by using the 3DS-MAX computer graphical program. At first glance, it is seen that the shapes obtained by the models are similar to the ones that can be observed in real samples.

The properties of bioactive substances obtained from seaweeds and their applications in textile industries

2017 ◽  
Vol 48 (1) ◽  
pp. 361-401 ◽  
Author(s):  
M Janarthanan ◽  
M Senthil Kumar
Keyword(s):  
Health Care ◽  
Bioactive Compounds ◽  
Animal Health ◽  
Antimicrobial Properties ◽  
Marine Macroalgae ◽  
Critical Problem ◽  
Bioactive Substances ◽  
Technical Textiles ◽  
Medical Textiles ◽  
Textile Industries

Technical textiles are one of the fastest emergent sectors of textile industries worldwide. Medical textiles and healthcare textiles are the most important development areas within technical textiles. A rapid advancement in the health care and hygiene sector together with an increase in health consciousness has made medical textiles an important field. In order to protect people against harmful pathogens, an antimicrobial textile has been developed and as a result, finishes began to evolve in recent years. A critical problem regarding healthcare and hygiene products chemical based synthetic antimicrobial finishes or coatings for infection control. To provide the potential solution and to avoid such critical problem, seaweeds may be used. Seaweeds are plant-like organisms that commonly live attached to rocks in the coastal areas. Seaweeds of brown, green and red colour contain major pigments such as chlorophyll, carotenoids, phycobiliproteins, beta carotene and lutein; these are used for the extraction of natural dyes in textiles. Marine macroalgae (seaweeds) is rich in bioactive compounds that could potentially be exploited as functional ingredients with potential medicinal, health care or pharmaceutical activities for both human and animal health applications. The present review discusses the research potential of different bioactive compounds and its salient features that are mainly responsible for the antioxidant and antimicrobial properties present in seaweeds and their applications in the area of medical textiles.

scholarly journals A Review on the Prospect for the Development of Nanostructured and Nanocomposite Aluminium-Alloyed Austempered Ductile Iron

2020 ◽  
Vol 4 (3) ◽  
Author(s):  
Abdullahi O Adebayo ◽  
Adebayo F Owa ◽  
Olawale O Ajibola ◽  
Sunday Borisade ◽  
Oluwole D Adigun ◽  
...  
Keyword(s):  
Ductile Iron ◽  
Review Paper ◽  
Processing Parameters ◽  
Austempered Ductile Iron ◽  
Scale Level ◽  
Bearing Materials ◽  
Production Techniques ◽  
High And Low Temperatures ◽  
Treatment Procedures ◽  
Iron Bearing

This review paper has established austempered ductile iron (ADI) as a classical material that has spectra of properties achieved by altering some processing parameters through heat treatment procedures. Concerted efforts have been made to equally explore the use of additives as additional materials to this all important alloy. The use of modifiers at ultra-fine or nano-scale level as additive to the melt prior casting has also been reviewed. However, the continuous quest for innovative approaches of upgrading the structural and mechanical characteristics of ductile irons has open up interest in the development of nanostructured and nanocomposite components in bulky iron bearing materials. This paper cross-examines few available literatures on the nanostructured ADI with the aim of adopting similar methodology in the development of nanostructured aluminium-alloyed DI and nanostructured aluminium-alloyed ADI. Emphasy is laid on reviewing the production techniques and treatment parameters on the processing of the developed nanostructured aluminium-alloyed DI and/or aluminium-alloyed DI nanocomposites and with respect to their usage at low, moderate and extremely high and low temperatures. Keywords— aluminium-alloyed austempered ductile iron; development; nano-tructured; nanocomposite; processing; modifiers

Polyetheresterurethane Based Porous Scaffolds with Tailorable Architectures by Supercritical CO2 Foaming

MRS Advances ◽  
2020 ◽  
Vol 5 (45) ◽  
pp. 2317-2330
Author(s):  
Marc Behl ◽  
Muhammad Yasar Razzaq ◽  
Magdalena Mazurek-Budzyńska ◽  
Andreas Lendlein
Keyword(s):  
Pore Size ◽  
Treatment Options ◽  
Three Dimensional ◽  
Processing Parameters ◽  
Attractive Alternative ◽  
Porous Scaffolds ◽  
Potential Candidate ◽  
High Porosity ◽  
Average Pore ◽  
Scaffold Materials

AbstractPorous three-dimensional (3D) scaffolds are promising treatment options in regenerative medicine. Supercritical and dense-phase fluid technologies provide an attractive alternative to solvent-based scaffold fabrication methods. In this work, we report on the fabrication of poly-etheresterurethane (PPDO-PCL) based porous scaffolds with tailorable pore size, porosity, and pore interconnectivity by using supercritical CO2 (scCO2) fluid-foaming. The influence of the processing parameters such as soaking time, soaking temperature and depressurization on porosity, pore size, and interconnectivity of the foams were investigated. The average pore diameter could be varied between 100–800 μm along with a porosity in the range from (19 ± 3 to 61 ± 6)% and interconnectivity of up to 82%. To demonstrate their applicability as scaffold materials, selected foams were sterilized via ethylene oxide sterilization. They showed negligible cytotoxicity in tests according to DIN EN ISO 10993-5 and 10993-12 using L929 cells. The study demonstrated that the pore size, porosity and the interconnectivity of this multi-phase semicrystalline polymer could be tailored by careful control of the processing parameters during the scCO2 foaming process. In this way, PPDO-PCL scaffolds with high porosity and interconnectivity are potential candidate materials for regenerative treatment options.

Open-Cell Metallic Porous Materials Obtained Through Space Holders—Part II: Structure and Properties. A Review

2016 ◽  
Vol 139 (5) ◽  
Author(s):  
Lenko Stanev ◽  
Mihail Kolev ◽  
Boris Drenchev ◽  
Ludmil Drenchev
Keyword(s):  
Structural Characteristics ◽  
Processing Parameters ◽  
Structure And Properties ◽  
Metallic Foams ◽  
Compressive Behavior ◽  
Foam Material ◽  
Open Cell ◽  
Production Techniques ◽  
Clear Information ◽  
Absorption Characteristics

This work presents an overview of structural characteristics and basic mechanical properties of the open-cell metallic foams obtained by different space-holder methods, which are discussed in Part I of the same review. The presentation is arranged with respect to foam material, and the structure and properties are compared for different space holders and production techniques. In order to have more clear information for the structures obtained and their relation with production techniques, many images are provided and discussed. Compressive behavior of the foams is shown, and stress–strain curves are analyzed with respect to the energy absorption characteristics. The analysis are made on the basis of different porosities and processing parameters. Some applications of the open-cell metallic foams are discussed in the end of the article.

Microstructural Variations in Melt-Spun Rapidly Solidified Ribbons

1985 ◽  
Vol 43 ◽  
pp. 54-55
Author(s):  
L. A. Bendersky ◽  
W. J. Boettinger
Keyword(s):  
Solid State ◽  
Processing Parameters ◽  
Heat Extraction ◽  
Solid State Reactions ◽  
Careful Examination ◽  
Ion Milling ◽  
Melt Spun ◽  
Wheel Side ◽  
Rapidly Solidified ◽  
Heat Extraction Rate

Rapid solidification produces a wide variety of sub-micron scale microstructure. Generally, the microstructure depends on the imposed melt undercooling and heat extraction rate. The microstructure can vary strongly not only due to processing parameters changes but also during the process itself, as a result of recalescence. Hence, careful examination of different locations in rapidly solidified products should be performed. Additionally, post-solidification solid-state reactions can alter the microstructure.The objective of the present work is to demonstrate the strong microstructural changes in different regions of melt-spun ribbon for three different alloys. The locations of the analyzed structures were near the wheel side (W) and near the center (C) of the ribbons. The TEM specimens were prepared by selective electropolishing or ion milling.

Conditions for atomic imaging of mullite

1989 ◽  
Vol 47 ◽  
pp. 418-419
Author(s):  
T. A. Epicier ◽  
G. Thomas
Keyword(s):  
Oxygen Vacancies ◽  
High Resolution Electron Microscopy ◽  
Ceramic Materials ◽  
Work Conditions ◽  
Real Space ◽  
Potential Candidate ◽  
Silicate Mineral ◽  
Resolution Electron ◽  
The Subject ◽  
Aluminium Silicate

Mullite is an aluminium-silicate mineral of current interest since it is a potential candidate for high temperature applications in the ceramic materials field.In the present work, conditions under which the structure of mullite can be optimally imaged by means of High Resolution Electron Microscopy (HREM) have been investigated. Special reference is made to the Atomic Resolution Microscope at Berkeley which allows real space information up to ≈ 0.17 nm to be directly transferred; numerous multislice calculations (conducted with the CEMPAS programs) as well as extensive experimental through-focus series taken from a commercial “3:2” mullite at 800 kV clearly show that a resolution of at least 0.19 nm is required if one wants to get a straightforward confirmation of atomic models of mullite, which is known to undergo non-stoichiometry associated with the presence of oxygen vacancies.Indeed the composition of mullite ranges from approximatively 3Al2O3-2SiO2 (referred here as 3:2-mullite) to 2Al2O3-1SiO2, and its structure is still the subject of refinements (see, for example, refs. 4, 5, 6).

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