Search results

The main role of polymer optical fibers is to transmit light or optical signal to a specified spot. In the case of side emitting plastic optical fibers the light leaks out from their surface. This sidelight can be used for creation of optically active textile structures providing opportunities to highlight people and objects without the need for external exposure. Due to the transmission loss, the intensity of radiation emitted in any direction decays exponentially along the fiber axis with increasing distance from the light source. The main aim of this contribution is evaluation of side emitting plastic optical fibers light intensity in dependence on the distance from light source. The special device for measurement of surface and cross section light intensity in various distances from light source was developed. The dependence of surface and cross section light intensity on the distance from light source will be expressed by the exponential type model with attenuation factor as the rate parameter. The influence of the optical fiber type and diameter on the attenuation factor of surface and cross section light intensity will be quantified.

PEN fibres are well known for their high performance properties, resistance, and good tensile properties. Their potential markets are the packaging, film and fibre markets. For tyre yarns in particular, the response to dynamic deformations at elevated temperatures is interesting. The ultimate modulus of PEN fibres is substantially higher than that of polethylenetrephtalate (PET). However, in the amorphous domains of PEN, the rotation of the naphthalene rings induces conformational transitions, which negatively influence the dynamic mechanical properties (Militký, 1999)

The main aim of this contribution is to measure and characterize the dynamic mechanical spectra of PEN fibres. These spectra are obtained at various levels of pre-straining. The analysis is based on the real part of the dynamic modulus and on an evaluation of the loss tangent. The simple model of dynamic behaviour based on the standard linear viscoelastic body is presented. The special apparatus for measuring dynamic behaviour under various types of deformation (tension, compression, bending, shearing) is described in detail.

Visual and subjective methods for evaluation of surface appearance irregularity of chemically bonded nonwovens are compared. The image analysis system LUCIA is used for estimation of characteristics describing appearance. The analysis of subjective and objective estimates of surface appearance irregularity is realized by the coefficient of variation and by the ANOVA type model.

The surface roughness is one of the main parts of hand prediction. Classical method of surface roughness measurements is based on the surface profile measurement. Characteristic of roughness is then variation coefficient of surface profile (surface height variation). The main aim of this work is to estimate the surface profile complexity by using variogram (structure function). The surface profile variation is classified to the group according to short‐ and long‐range dependence. The concept of fractal dimension is proposed especially for long‐term correlation cases. The applicability of the proposed approach is demonstrated on the typical heat protective clothing fabrics and compared with the results of surface roughness evaluated by the KES system.

It is well‐known that clean room textiles are acting as a barrier protecting humans against the surrounding atmosphere or vice versa. These textiles are produced in the limited range of porosity and the air permeability. The porosity calculated from fabric geometry and the air permeability of two typical clean room textiles of Czech production are measured. The variation of air permeability is described by the analysis based on the coefficient of variation and spatial autocorrelation. The air permeability of composite textiles of multiple layers is predicted from a simple model. This model is based on the idea of a combination of air pressure drop in individual layers. The predicted air permeability is compared with experimental measurements.

The main aim of this paper is description of new apparatus and approach for contact less evaluation of surface roughness. For characterization of surface roughness, the procedures based on classical and non‐classical (complexity) parameters are proposed.

For obtaining the roughness profile in the selected direction (on the line transect of the surface), the special arrangements of textile bend around sharp edge is used. The image analysis is used for extraction of surface profile. The system of controlled movement allows one to obtain surface roughness profile in two dimensions.

By using aggregation (cut length principle), the roughness resolution is decreased and roughness profile is created without local roughness variation. After application of cut length principle, the direct combination of slices leads to the creation of roughness surface.

There exists plenty of roughness characteristics based on standard statistics or analysis of spatial processes. For evaluation of suitability of these characteristics, it will be necessary to compare results from sets of textile surfaces.

The measurement of fabric roughness by an RCM device is useful as simple tool for description of roughness in individual slices and in the whole rough plane. This method replaces the traditional contact stylus profiling methods

The reconstruction of surface roughness from individual slices. The utilization of aggregation principle for creation of micro and macro roughness. The evaluation of roughness parameters based on the geometrical characteristics, harmonic analysis and complexity indices.

Examines wool/polyester blended fabrics with a view to finding the optimal blend in relation to suitable utility, surface and handling properties. Concludes that a simple general mixing rule is possible for use in producing the required optimum blends.

This study aims to develop multifunctional, namely, superhydrophobic, flame-retardant and antibacterial, coatings over cotton fabric, using casein as green-based flame-retardant and silver nanoparticles as antibacterial agent by solution immersion method.

The cotton fabric is first coated with casein to make it flame-retardant. AgNPs synthesized using Cinnamomum zeylanicum bark extract is coated over the casein layer. Finally, stearic acid is used to coat the cotton to make it superhydrophobic. X-ray diffraction, transmission electron microscopy analysis and ultraviolet-visible spectroscopy are used to investigate the produced AgNPs. The as-prepared multifunctional cotton is characterized by scanning electron microscopy, energy dispersive X-ray analysis and attenuated total reflection-infrared studies. Flame test, limiting oxygen index test and thermogravimetric analyzer studies have also been performed to study the flame-retardant ability and thermal stability of treated fabric, respectively. The antibacterial effect of the coatings is evaluated by disc-diffusion technique. Water contact angle is determined to confirm the superhydrophobic nature of cotton fabric.

The outcomes of this study showed that the prepared multifunctional cotton fabric had maximum contact angle of greater than 150° with good flame retardancy, high thermal stability, greater washing durability and high antibacterial activity against the growth of Pseudomonas aeruginosa and Acinetobacter indicus. Additionally, the as-prepared superhydrophobic cotton showed an excellent oil–water separation efficiency.

The trilayered multifunctional cotton fabric has limiting washing durability up to 20 washing cycles. Treated functional fabric can be used as an antibacterial, therapeutic, water repellent and experimental protective clothing for medical, health care, home curtains and industrial and laboratory purposes.

The study brings out the robustness of this method in the development of multifunctional cotton fabrics.

The objective of this work was to use the spinning waste in form of short fibres for the preparation of nano size fillers in nanocomposite applications. The present paper concerns with the jute fibres as the source to produce nanocellulose by high energy planetary ball milling process and its potential applications as fillers in biodegradable nanocomposite plastics used in automotives, packaging and agriculture applications. Influence of various milling conditions like nature of milling (i.e. dry or wet), milling time and ball size are studied on the particle size distribution and morphology of jute nanoparticles obtained. Wet milling in the deionised water resulted into particle size refinement below 500 nm with narrow size distribution after 3 hours of milling at the cost of small amount of contaminations introduced from milling media.