4,460 research outputs found
Smart Textiles Production
The research field of smart textiles is currently witnessing a rapidly growing number of applications integrating intelligent functions in textile substrates. With an increasing amount of new developed product prototypes, the number of materials used and that of specially designed production technologies are also growing. This book is intended to provide an overview of materials, production technologies, and product concepts to different groups concerned with smart textiles. It will help designers to understand the possibilities of smart textile production, so that they are enabled to design this type of products. It will also help textile and electronics manufacturers to understand which production technologies are suitable to meet certain product requirements
Visco-Elasto-Capillary Thinning and Break-Up of Complex Fluids
Submitted to Annual Rheology Reviews, 2005.The progressive break-up of an initially stable fluid column or thread into a
number of smaller droplets is an important dynamical process that impacts many
commercial operations from spraying and atomization of fertilizers and pesticides, to
paint application, roll-coating of adhesives and food processing operations such as
container- and bottle-filling. The progressive thinning of a fluid filament is driven by
capillarity and resisted by inertia, viscosity and additional stresses resulting from the
extensional deformation of the fluid microstructure within the thread. In many
processes of interest the fluid undergoing break-up is non-Newtonian and may contain
dissolved polymer, suspended particles, surfactants or other microstructural
constituents. In such cases the transient extensional viscosity of the fluid plays an
important role in controlling the dynamics of break-up. The intimate connection
between the degree of strain-hardening that develops during free extensional flow and
the dynamical evolution in the profile of a thin fluid thread is also manifested in
heuristic concepts such as âspinnability’, âtackiness’ and âstringiness’. In this review
we survey recent experimental and theoretical developments in the field of capillarydriven
thinning and break-up with a special focus on how quantitative measurements
of the thinning and rupture processes can be used to quantify the material properties of
the fluid. As a result of the absence of external forcing the dynamics of the necking
process are often self-similar and observations of this âself-thinning’ can be used to
extract qualitative, and even quantitative, measures of the transient extensional
viscosity of a complex fluid.NASA, NSF, Schlumberger Foundatio
Textile Manufacturing Processes
Textile manufacturing is an important subject in textile programs and processing industries. The introduction of manmade and synthetic fibers, such as polyester, nylon, acrylic, cellulose, and Kevlar, among others, has greatly expanded the variety of textile products available today. In addition, new fiber development has brought about new machines for producing yarns, fabrics, and garments. Textile Manufacturing Processes is a collection of academic and research work in the field of textile manufacturing. Written by experts, chapters cover topics such as yarn manufacturing, fabric manufacturing, and garment and technical textiles. This book is useful for students, industry workers, and anyone interested in learning the fundamentals of textile manufacturing
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The Role of Redox Chemistry in Mussel Byssus
The mussel byssus is a collection of extra-organismal, acellular, proteinaceous load bearing structures that are radial displayed and utilized by marine mussels to secure themselves to a multitude of substrates. A single byssal thread can be subdivided into the loading bearing thread and adhesive plaque, which provide tensile strength and adhesive strength respectively. Both regions of the byssus face their own unique challenges and have devised independent mechanisms to protect themselves against oxidative stresses. Here we present evidence the mussel utilizes isolated redox compartments to protect 3, 4-dihydroxyphenylalanine (Dopa) from oxidative damage in both the thread and plaque, permitting long lasting mechanical performance of the byssus. The byssus thread is an extremely tough core-shelled fiber that dissipates substantial amounts of energy during tensile loading. The mechanical performance of the shell is critically reliant on Dopa’s ability to form reversible iron-catecholate complexes at pH 8. However, the formation of these coordinate crosslinks is undercut by Dopa’s oxidation to Dopa-quinone, a spontaneous process at seawater conditions. Using a combination of electron and atomic force microscopy we identify a previously undescribed stratum situated between the core and shell. Spectroscopy results indicate this region is rich in thiol and thus will be called the thiol rich layer (TRL). We propose the TRL acts as an electron sink to protect the shell against oxidation. Additionally, indentation type atomic force microscopy reveals the TRL has intermediate mechanical properties which act as a mechanical buffer between the shell and core. The adhesive plaque is also reliant on Dopa. Dopa in the plaque is primarily responsible for strong adhesion but only if protected from oxidation at the adhesive-substratum interface. Dopa oxidation is thermodynamically favorable in seawater yet barely detectable in mature plaques. Experiments were designed to understand how plaques insulate Dopa-containing mfps against oxidation. Spectrometry and confocal fluorescence results indicate seawater sulfate triggers a mfp3 and mfp6 liquid-liquid phase separation (LLPS). Subsequently, cyclic voltammetry of LLPS material demonstrates DOPA’s redox potential is phase dependent. Furthermore, mass spectrometry and redox exchange assays indicate Dopa-containing mfp-3 and mfp-6 in phase-separated droplets remain stable despite rapid oxidation in the equilibrium solution. Taken together, the results suggest that a cohort of oxidation-prone proteins is endowed with phase-dependent redox stability. Moreover, in forming LLPS compartments, Dopa-proteins become reservoirs of chemical energy which can be called upon in the event of oxidative damage
Multiscale approach in the assessment of nanocellulose-based materials as consolidants for painting canvases
This thesis investigates mainly the use of nanocellulose-based treatment for the consolidation of degraded cotton canvases of modern paintings and includes within this some case studies on linen canvases (sized and unsized) and 19th cent. historical samples from paintings. It. uses a multi-scale analytical approach where primarily controlled relative humidity dynamic mechanical analysis (DMA-RH) was used to evaluate the effect of the novel nanocellulose based preparations. It aims at quantifying the advantages, disadvantages, and limitations of their application. Initially, the baseline viscoelastic response to RH variations of a degraded cotton canvas was measured by DMA-RH. This technique was used further together with SEM to assess morphologically and mechanically 6 traditional consolidants including natural such as animal glue and synthetic materials. Following the same protocol, two solutions of nanocellulose-based consolidants developed in the frame of the Nanorestart project were assessed. These materials consisted of nanocellulose dispersions in water or water/ethanol and nanocomposites of nanocellulose-reinforced cellulose derivatives in polar/apolar solvents. Overall, higher consolidation at lower weight added was measured for the nanocellulose-based treatments tested when compared to the traditional consolidants. The penetration of the consolidant in the canvas also shows to greatly differ between treatments with the nanocellulose showing low penetration. Higher mechanical response to RH was also measured after treatment in particular with the water-based treatment. The results demonstrate how the adhesion, measured here at the nanoscale, and consolidant penetration into the canvas are dominant factors for the development of consolidation treatment for painting canvases. The assessment of the novel consolidants was finally carried out on historical canvases. Most treatments show to perform well on historical paintings in terms of handling properties, penetration and surface appearance and consolidation. Preliminary time-resolved neutron radiography with new purpose built sample chamber and RH controller provided visual information on time-dependent moisture response of the samples
Textile materials
In this specialised publication, the reader will find research results and real engineering developments in the field of modern technical textiles.
Modern technical textile materials, ranging from ordinary reinforcing fabrics in the construction and production of modern composite materials to specialised textile materials in the composition of electronics, sensors and other intelligent devices, play an important role in many areas of human technical activity. The use of specialized textiles, for example, in medicine makes it possible to achieve important results in diagnostics, prosthetics, surgical practice and the practice of using specialized fabrics at the health recovery stage.
The use of reinforcing fabrics in construction can significantly improve the mechanical properties of concrete and various plaster mixtures, which increases the reliability and durability of various structures and buildings in general.
In mechanical engineering, the use of composite materials reinforced with special textiles can simultaneously reduce weight and improve the mechanical properties of machine parts. Fabric- reinforced composites occupy a significant place in the automotive industry, aerospace engineering, and shipbuilding. Here, the mechanical reliability and thermal resistance of the body material of the product, along with its low weight, are very relevant.
The presented edition will be useful and interesting for engineers and researchers whose activities are related to the design, production and application of various technical textile materials
Mechanical Properties of Poly (vinyl alcohol) Based Blends and Composites
One of the most important product specifications in design of materials for different applications is to closely match desired mechanical properties of the target. The soft tissue could be very elastic such as blood vessels and skin, whereas others are soft and non-elastic such as fat tissue. Soft human tissue has a diverse structural component that give them the different feel, texture, shape, and mechanical properties.
Poly (vinyl alcohol) (PVA) as hydrophobic polymer has outstanding features such as very good physico-mechanical properties, nontoxicity and biocompatibility, and high swelling properties which makes them favorable for biomaterial and biomedical applications. By physically crosslinking PVA, one can eliminate residual amount of toxic crosslinking agent compared to chemically crosslinking. Moreover, by adding fillers (particle or fibers) to PVA and making PVA based blends, desirable mechanical properties can be achieved which, consequently can mimic the different human tissue texture and properties.
Different naturally based fillers such as chitosan, micro crystalline cellulose (MCC), and cotton fibers were added to improve the mechanical properties. Also, PVA was blended with xanthan gum and sorbitol to improve the elasticity of the material
DESIGN OF ROBUST HYDROGEL BASED ON MUSSEL-INSPIRED CHEMISTRY
The structure of catechol is found in mussel adhesive proteins and contributed to both wet-resistant adhesion and cohesive curing of these proteins. A synthetic nano-silicate, Laponite was incorporated into catechol-containing hydrogels and the hydrogel network-bound catechol formed strong reversible interfacial interaction with Laponite. The contribution of incorporated catechol-Laponite reversible interfacial interactions to the mechanics of hydrogels constructed by different strategies was studied. In the first strategy, Laponite and catechol were introduced into the double network hydrogel (DN) via the free radical co-polymerization of a catechol-containing monomer, backbone monomer, and crosslinker. The introduction of catechol-Laponite interactions significantly improved the compressive strength and toughness of DN without compromising the compliance of the hydrogel and enabled the DN’s ability to recover its mechanical properties during successive loading cycles. In the second strategy, Laponite was combined with an catechol-modified 4-armed poly(ethylene glycol)-based adhesive, which cured in the present of an oxidative catalyst, sodium periodate, to form an injectable naoncomposite tissue adhesive hydrogel. The addition of up to 2 wt% Laponite significantly reduced the cure time, enhanced the bulk mechanical and adhesive properties of the adhesive due to strong catechol-Laponite interfacial binding. Additionally, subcutaneous implantation result showed that incorporation of Laponite effectively promote cell infiltration into the nanocomposite hydrogel, providing a simple way to improve the bioactivity of a bio-inert, synthetic poly(ethylene glycol)-based adhesive. On the basis of the second strategy, higher concentration of Laponite was combined with catechol-modified 6- and 8-armed PEG-based adhesive to form a nanocomposite hydrogel without introducing additional oxidative catalyst in the third strategy. This hydrogel underwent unique dynamic crosslinking process. At early stage it recovered to its original stiffness immediately after failure induced by shear strain up to 1000% interactions and could be reshaped to adhere to the contour of tissue due to the catechol-Laponite interactions and loosely chemically crosslinked network structure, respectively. The hydrogel gradually transformed to a densely chemically crosslinked network meanwhile fixed its shape as tissue sealant. This dissertation provided an insight of exploiting mussel-inspired chemistry in designing a hydrogel with specific materials property
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