The influence of textiles on Corona discharge created around a human fingertip

A corona discharge is a visible, electrical discharge observed in gases, which occurs on the surface of charged conductors. In our research, the discharges were generated around human fingertips and recorded in the form of films during the test while a number of people were in contact with different textiles for a short period. The aim of our experiments was the estimation of the possibility of using corona-discharge-films (CDF) for the investigation of the impact of textiles on the CDF of human fingertips. This article describes the investigation, aimed at determining if a test-person short period of contact with textiles, such as knitted acrylic, wool and viscose fabrics, influences the corona discharge of the test-person. The research results confirmed these assumptions

Estimation of the EMR shielding effectiveness of knit structures

This paper describes the creation of and tests petformed on knit structures of three types (left-right stitch (I), double-layer (II), and double-layer with additional fillings (III)), which contain ferromagnetic materials and electroconductive materials and are designed for individual protection against occupational hazard. The ferromagnetic material is composed of two bunches of twisted filaments of ferromagnetic stainless steel made by Bekaert, Belgium, and the electroconductive material is a thread made of cotton and copper wire covered by silver made by Swiss Shield (R) yarns, Switzerland. Both the ferromagnetic and electroconductive materials form a hybrid yarn. Shielding effectiveness (SE) tests on knit structures were performed by the Central Institute for Labour Protection - National Research Institute, Poland and by the Institute of Architecture of Textiles, Poland. Analysis of the structures indicates a SE from both the electrical field and magnetical field in some narrow ranges

Images of corona discharges as a source of information about the influence of textiles on humans

The aim of the experiment was to bring closer the possibilities of using corona discharge photography (CDP), with special emphasis on the impact of textiles on corona discharge photography of human fingertips in contact with those textiles. The article describes an investigation concerning a short period of contact with textiles and their influence on human parameters such as blood pressure (BP) and heart beat (HB) as well as images of corona discharges (ICD). The authors were searching for a new method of demonstrating the influence of textiles on human subjects. As the research involved contact of textiles with human skin, certain static and friction issues were raised. Textile materials were chosen for the experiments on the basis of their tribological features. The ICDs used here were created as a result of placing body parts, e.g. fingers, in the area of a strong electrical field of high voltage (10 KV) and high frequency (1024 Hz). A digital camera placed within the area of discharge recorded this phenomenon. The temperature, air humidity, and air pressure in the examination room as well as gender, age, HR, BP and in the case of female volunteers, their menstrual cycles, exerted an effect on ICD in the study group. ICD of human beings seems to be a kind of marker of tribological features of textile materials

Textile structures modeled on a spider's net

Innovative textile fabrics modelled on the structure of a spider web can find application in the reinforcing of composites in conditions of where a centrifugal force occurs, for example rotational discs. At the Institute of Architecture of Textile at the Technical University of Łódź research work is carried out on mechanised production of woven fabrics whose struc- ture is modelled on a spider webweb. The paper presents a review of textile techniques and technologies from the point of view of their usefulness for producing fabrics of a flat round net type structure modelled on the structure of a spider web.There is also an analysis of the mechanical properties of the different textile structures from the point of view of fulfilling the requirements to operate in conditions which are affected by a centrifugal force

Micro-CT supporting structural analysis and modelling of ropes made of natural fibers

This paper describes the modelling of the structure and mechanical parameters of rope components made of natural fibers. Modern X-ray micro-tomography (Micro-CT) was employed to measure the parameters of the internal structure of the multi-component yarns making up rope and utilized as a basic model of twisted rope. The results allowed calculation of the tensions generated in the component yarns and detection of the unevenness of the filling of the component yarns by fibers, which was clearly visible in cross-section. The unevenness of twist measured as a function of distance from the center of the yarn was also detected. The unevenness of fiber distribution in the twisted element decreased its intensity, starting from the surface of the yarn and going deeper into the structure. Migration of the fibers in the frame of the circumference of the component yarns was associated with the mutual slide of single fibers

Influence of different kind of clothing material on selected cardiovascular, respiratory and psychomotor parameters during moderate physical exercise

Objectives: The aim of the experiment was to analyze the influence that the clothing material may have on human physiology and thermal comfort both at rest and physical effort to answer the question which fabric is better, a natural or a synthetic one. Materials and Methods: We measured some psychomotor parameters: critical flicker frequency (CFF), reaction time to auditory/visual stimuli (RT), concentration of attention (CA); cardiovascular parameters: blood pressure (BP), heart rate (HR) and respiratory parameters: tidal volume (VT), minute ventilation (VE), oxygen consumption (VO2), carbon dioxide output (VCO2), respiratory exchange ratio (RER) in human volunteers before, during and after physical effort. The subjects performed a 15-min treadmill test on treadmill wearing clothes made of two different materials: 100% coarse wool and 100% acrylic. An interview was conducted directly before the exercise test to assess the subjects' general mood and wellbeing on that day. Besides, before and after the test, the subjects in their own words described the sensation they felt with respect to the physiological comfort of particular clothing. Results: The results showed that wearing clothes made of different fabrics had some influence on the cardiovascular and respiratory parameters during physical effort but it did not have any effect on the psychomotor skills. The perception of physiological comfort by the subjects wearing coarse wool or acrylic depended on their physiological state and differed at rest and after the physical effort. Conclusions: The course of physiological processes depends on the kind of clothing a given person is wearing. It is not possible to clearly define which of the two clothing materials: natural — wool, or synthetic — acrylic is better. Each of them exerts a different effect on the human organism. The usefulness of a given type of clothing material seems to depend on the human physiological state and the related thermoregulatory processes

Fingertip skin models for analysis of the haptic perception of textiles

This paper presents finite element models of the fingertip skin which have been created to simulate the contact of textile objects with the skin to gain a better understanding of the perception of textiles through the skin, the so-called hand of textiles. Many objective and subjective techniques have already been developed for analysing the hand of textiles; however, none of them provide exact overall information concerning the sensation of textiles through the skin. As the human skin is a complex heterogeneous hyperelastic body composed of many particles, some simplifications had to be made at the early stage of building the models; however, their utilitarian value was maintained. The models relate only to mechanical loading of the skin. They predict a low deformation of the fingertip skin under the pressure of virtual heterogeneous material: acrylic, coarse wool, and steel

Analysis of hybrid woven fabrics with shape memory alloys wires embedded

Until recently, Shape Memory Alloys (SMAs) were predominantly developed for applications in the biomedical and engineering industry, and only a limited number of applications in textiles are known. Fabrics made of natural fibres (e. g. cotton, flax and their mixtures) present many advantages, such as wearing comfort, but they are subject to creasing. The aim of this study was to investigate the possibility of compensating for this disadvantage by using SMAs to create aesthetic low crease flax/cotton fabrics. Body Temperature SMAs (BT SMA) that regain their (straight) form when they are subject to human body temperature were used for this purpose. Clothing and bed sheeting are potential applications of these hybrid structures, which become wrinkle-free when they are exposed to the heat of the body, a hair dryer or that generated by an electrical current. The materials selected to achieve this purpose were the following: (1) textile yarns (e. g. single cotton or flax/cotton yarns, two-fold flax yarns and two types of loop fancy yarns) and (2) BT SMA wires of 300 mu m diameter. A power weaving loom and a hand-weaving shuttle loom were used to embed the SMA wires, and four types of hybrid fabrics were produced. The thickness, wrinkle recovery, dimensional stability as well as the cohesion of the SMA wires in the woven fabric were tested. All the tests were performed before and after a washing cycle for both the hybrid and reference fabrics. An increase in thickness was noticed after washing, and the recovery time after crushing varied according to the type of fabric. The slippage of SMA wires from the fabrics was noticed for all the samples, which was dependent on the type of yarns used, their linear density and the weaving process

A review of contemporary techniques for measuring ergonomic wear comfort of protective and sport clothing

Protective and sport clothing is governed by protection requirements, performance, and comfort of the user. The comfort and impact performance of protective and sport clothing are typically subjectively measured, and this is a multifactorial and dynamic process. The aim of this review paper is to review the contemporary methodologies and approaches for measuring ergonomic wear comfort, including objective and subjective techniques. Special emphasis is given to the discussion of different methods, such as objective techniques, subjective techniques, and a combination of techniques, as well as a new biomechanical approach called modeling of skin. Literature indicates that there are four main techniques to measure wear comfort: subjective evaluation, objective measurements, a combination of subjective and objective techniques, and computer modeling of human–textile interaction. In objective measurement methods, the repeatability of results is excellent, and quantified results are obtained, but in some cases, such quantified results are quite different from the real perception of human comfort. Studies indicate that subjective analysis of comfort is less reliable than objective analysis because human subjects vary among themselves. Therefore, it can be concluded that a combination of objective and subjective measuring techniques could be the valid approach to model the comfort of textile materials

Recycling of Pretreated Polyolefin-Based Ocean-Bound Plastic Waste by Incorporating Clay and Rubber

Plastic waste found in oceans has become a major concern because of its impact on marine organisms and human health. There is significant global interest in recycling these materials, but their reclamation, sorting, cleaning, and reprocessing, along with the degradation that occurs in the natural environment, all make it difficult to achieve high quality recycled resins from ocean plastic waste. To mitigate these limitations, various additives including clay and rubber were explored. In this study, we compounded different types of ocean-bound (o-HDPE and o-PP) and virgin polymers (v-LDPE and v-PS) with various additives including a functionalized clay, styrene-multi-block-copolymer (SMB), and ethylene-propylene-based rubber (EPR). Physical observation showed that all blends containing PS were brittle due to the weak interfaces between the polyolefin regions and the PS domains within the polymer blend matrix. Blends containing clay showed rough surfaces and brittleness because of the non-uniform distribution of clay particles in the polymer matrix. To evaluate the properties and compatibility of the blends, characterizations using differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and small-amplitude oscillatory shear (SAOS) rheology were carried out. The polymer blend (v-LDPE, o-HDPE, o-PP) containing EPR showed improved elasticity. Incorporating additives such as rubber could improve the mechanical properties of polymer blends for recycling purposes