Izabela Ciesielska-Wrobel

The hand of textiles – definitions, achievements, perspectives – a review

The aims of this wide-range review concerning the hand of textiles are to present: (1) the diversity of definitions and the complexity of analysis of the hand of textiles; (2) the authors’ own definition of the hand of textiles and division of techniques of its analysis. The review presents objective techniques, subjective techniques along with their physiological background, and a combination of techniques as well as a new biomechanical approach called modelling of skin. The structure of the paper is as follows: • definitions of the hand of textiles, including the authors’ definition; • objective techniques of hand measurement; • physiological approach; • subjective techniques of hand measurement; • combination of objective and subjective techniques; • modelling techniques and the biomechanics approach for measurement of the hand of textiles; • division of hand measurement techniques according to the authors. This paper gives a review of the international literature from 1930 to 2010 concerning the hand of textiles and other related subjects like skin physiology, perception though the skin, and biomechanical aspects of the skin. Due to obvious limitations the authors have chosen only those papers which seemed to have the strongest relation to the presented topic and which are at the same time the most interesting studies in the authors’ opinion.

The analysis of attenuation of electromagnetic field by woven structures based on hybrid fancy yarns

In this paper we present an analysis of attenuation by woven structures produced from hybrid yarns. The woven structures have been designed for protection against electromagnetic fields (EMFs). The idea of creating hybrid yarns that may intensively protect against EMFs comes from the analogy discovered between the construction of a fancy bunch yarn and an electric system composed of electro-conductive solenoids on a ferromagnetic material connected in series and then in parallel. The application of hybrid fancy yarn as a weft made of copper as a special effect thread insulated with lacquer and wrapped around a core of steel thread in a textile fabric will enable EMF attenuation as a result of inducing an electromotive force in the special effect thread and magnetizing the core thread. In this way, the designed electric circuit (textile fabric) in the variable primary EMF will be the source of a secondary EMF directed opposite to the direction of the primary field. The fabricated woven structures present electrical and magnetic components of EMF attenuation in some narrow ranges.

Basic Comparison of the Properties of the Loop and Frotte Yarns, Woven and Knitted Fabrics

Abstract Both loop fancy yarns and frotte fancy yarns belong to the group of yarns with continuous effects. The difference between frotte and loop yarn relies on the fact that the loop yarn is constructed with two core yarns and the frotte yarn is constructed with only one core yarn. The differences are evident in the shape of these two types of fancy yarns. These shape differences are the functions of the tensions of component yarns during the twisting process. The shape and construction of the fancy yarn influence its properties. The properties of loop and frotte fancy yarns, woven and knitted fabrics are compared in this article in order to find out the optimal yarn’s and fabric’s production condition to satisfy the final user and maintain low production costs. In terms of economy aspects only, the frotte fancy yarns are believed to be cheaper in production due to lower quantity of components utilize for their production to compare with loop fancy yarns, under conditions of the same settings of ring twisting frame.

Application of micro-computed tomography (micro-CT) to study unevenness of the structure of yarns

A study was conducted on the structure of a single cotton yarn using micro-computer tomography (micro-CT). This article describes two important parameters determining the unevenness of yarn structure, i.e. the migration of staple fibers and packing density of staple fibers in the yarn cross-section. Relationships were found between the variation of staple fiber migration characteristics and the relationship between yarn durability and twist. For the boundary value, the radius and range of migration are the highest, and the variation coefficient of the fiber migration range is the lowest. The number of fibers in the yarn cross-section decreases with twist. Above the boundary twist value, the number of fibers in the yarn cross-section stabilizes at the value corresponding to the number of fibers in the boundary twist.

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.

Dry heat transfer from the skin surface into textiles: subjective and objective measurement of thermal haptic perception of textiles – preliminary studies

The aim of the study is the assessment of thermal haptic perception of textiles based on subjective and objective evaluations. This subjective evaluation is based on the questioning of human subjects about their thermal perception related to touching textiles. The objective evaluation relies on measurements of temperature changes between fabrics and a human fingertip when textiles are touched. The proposed objective method for estimation of the thermal haptic perception of textiles is far more precise than traditional subjective methods based on the assignment of certain verbal or numerical parameters to the perceived features of textiles. The results provided by the objective methods are congruent with an analytical approach, utilising the heat transfer formula to calculate the heat lost from fingertip skin into textiles, as well as with the theory explaining the boosting of the warm feeling of textiles due to their roughness. It was found that the QMAX parameter of the textiles is in opposition to the results of subjective assessment and partly to the results of objective assessment.

Woven Fabrics Containing Hybrid Yarns for Shielding Electromagnetic Radiation

The aim of the study was to verify whether the construction of a specific hybrid yarn containing a ferromagnetic core and electroconductive wire introduced into woven fabric will improve the shielding effectiveness (SE) in comparison with reference fabrics made of the same raw materials but introduced into woven fabrics as plain wefts, not twisted into the hybrid yarn. Hybrid yarn made of electroconductive materials allows the creation of a set of solenoids with a ferromagnetic core made of steel yarn and a solenoid of conductive effect yarns made of copper. The woven fabric made of these yarns placed into an alternating electromagnetic field (EMF) exhibits a phenomenon where an alternating electric voltage is generated between the ends of the copper solenoid, and alternating magnetisation of the ferromagnetic core takes place. Twelve fabrics were produced, nine of which differed in the density with which the hybrid yarns were introduced as wefts, i.e. once every 25×2 tex cotton yarn, every two cotton yarns, and every three cotton yarns, and the remaining three were reference fabrics, without hybrid yarn. It was found that if measured at a frequency of 30 MHz, the fabrics containing hybrid yarns had 60% higher SE than the reference ones.

Shielding of electromagnetic radiation by multilayer textile sets

This paper presents the continuation of research on shielding efficiency (SE) of electromagnetic radiation (EMR) by woven fabric made of cotton (warps and wefts) and a hybrid yarn (wefts). This hybrid yarn was made of stainless steel yarn by Bekinox wrapped with an enamelled copper wire from Synflex Elektro GmbH, Germany. The pitch of copper coil on a hybrid yarn equals 3 mm. The wefts were introduced into the fabric in the following order: 1 hybrid yarn, 1 cotton yarn, 1 hybrid yarn, 1 cotton yarn, etc. The construction of this specific fabric was proven to be the most efficient in terms of the hybrid weft construction and the fabric construction to shield EMR among other previously tested fabrics with different weft configuration. The current study proposes to verify the effect of the number of layers of the fabrics and their mutual configuration on the final SE of the multilayered set. Some of the most interesting findings of this study are that increasing the number of layers placed on top of one another with an offset angle of 0° to more than two does not provide a higher SE; however, using three such layers provides an SE of 56 dB, which is over two times higher than that provided by a single layer. Increasing the number of layers of fabric aligned at an angle of 45° provides a higher SE only for a frequency of 30 MHz.

The influence of designs of protective uniforms on firefighters’ performance during moderate physical exercises

The aim of this study was to verify whether the minor differences in the design of uniforms and their fit can be quantified in terms of their impact on firefighters’ cardiorespiratory parameters and subjective perception of these uniforms. The impact of minor design improvements compared to the existing designs of personal protective clothing (PPC) is still relatively difficult to quantify due to the lack of sensitive devices used in smart measuring methodologies; however, the perception of these slight differences is reported by PPC users. The impact of these design differences in PPC on firefighters was studied via physiological tests based on occupation-related activities in which cardiorespiratory parameters were monitored and three-dimensional (3D) silhouette scanning was performed on the firefighters. Apart from heart rate (beats/min), none of the other measured physiological parameters, for example, oxygen consumption (VO2, ml/min) demonstrated statistically significant differences when firefighters were testing uniforms: ergonomic (ER), standard (ST), bulky (BU), and reference outfit (RO), the latter being T-shirt and shorts. A statistically significant correlation was found between parameters measured via 3D body scanning and selected cross-sections of the silhouettes as well as subjective assessments of easiness of specific movement performance during the physiological test and assessment of bulkiness of the uniforms. There is a limited influence of the minor design differences between firefighters’ uniforms on the selected physiological parameters of the subjects wearing them. The outcome of the study can be utilized when performing the test on subjects and improving designs of PPC.

Mathematical model of haptic perception of temperature

The tactile perception of temperature of fabric measured by the thermocouple placed between fabric and a fingertip was analyzed. The experimental data were compared to the mathematical model of heat transfer between body and fabric. A high correlation between mathematical model, which presents a theoretical approach to heat transfer, and the experimental part was found. It proves that the very basic laboratory setup for measurement of heat transfer can be a reliable source of information concerning this phenomenon. It was proven that two time constants, τ and τL, and two temperature values, T0 and ΔT0, are the essential parameters to obtain a reliable agreement between the mathematical model and the experimental results.