In this paper the current distribution within woven electroconductive textile sheets was investigated using a computer program written for the purpose of the simulations. An iterative method of solving very large resistor networks used to model textile sheets is discussed. The factors taken into account are the conductivity of the fibres, the contact resistance between the fibres, the contact angle a between the fibres and the electrodes, the size and the aspect ratio of the textile sheets. Maps of the current distribution generated by the program are included.
An analysis of a complex tooth-lever mechanism to drive the thread guide (a device that forms cheese yarn packages) is presented in this paper. The described version of the mechanism design is equipped with elastic fenders that correct the positions of the thread guide lever. On the basis of a computer simulation of the mating of this device's basic links, a kinematic analysis of the thread guide motion was conducted. The influence of flexibility and the positions of the correction fenders on the parameters of thread guide motion has been considered in the analysis. The position of the initial point of the lever-fender contact with respect to the reverse position of the slide was optimised.
Fabric utility parameters most often depend on its mechanical properties. The most important strength parameters include unidirectional tensile strength, tear strength and elasticity properties. In this work we describe in detail the problem of tear stregnth, appropriate measurement methods and the correlation relationships between the results obtained by different tear methods. The measurements of tear stregnth were carried out for a chosen group of protective textiles. In addition, the unidirectional tensile strength was measured for the group of textiles mentioned above, and the correlation coefficients between the tensile strength and tear strength were calculated by different methods.
This paper presents the estimation of the apparent friction coefficient values of elastomer threads with a linear density of 169 dtex from the Italian enterprise Fillattice-Linel. The. tests were carried out on circular friction barriers with diameters from 0.1 mm to 10 mm, and within a preliminary tension range of 4 to 45 cN. A special measuring stand for online measurements was designed and constructed The stand included rotary tensiometric force gauges and a recording system which also analysed the test results obtained. The interpretation of the research results was performed on the basis of a mathematical model, which considers the friction properties according to the generalised friction law, as well as the threads rheological properties. Furthermore, a comparative analysis of the friction coefficients for elastomer and cotton threads was carried out. The investigations carried out prove that the optimum curvature radius of the friction barrier at which the resistance of pulling the elastomer thread over the barrier is the smallest, is about 0.25 mm, which means that it is ten times smaller than for cotton yarns. We stated that the variability character of the apparent friction coefficient for elastomer threads, in dependence on the friction barrier diameter is determined by the generalised friction law T = a N-n. The influence of the thread rheological properties on the value of the friction coefficient A is essentially smaller for elastomer threads when compared with cotton yarn, especially for barrier diameters commensurable with the diameters of the elastomer threads.
The aim of the study was to find new structured biopolymer blends bearing adjustable properties able to produce innovative materials. Apart from cellulose and three solvents (NaOH, N-methylmorpholine-N-oxide [NMMO] and 1-ethyl-3-methylimidazolium acetate [EMIMac]), 15 different polysaccharides were chosen to study the interactions ofpolysaccharides or their mixtures in solutions, as well as the solid state after forming. Dissolution screenings yielded promising polysaccharides, which were used for the preparation of cellulose/ polysaccharide solutions and subsequently for the shaping of blends with cellulose. The solubility and miscibility were evaluated by microscopy, DSC, particle analysis and rheology. Polysaccharides with a structure similar to that of cellulose, e.g., xylan, carrageenan or cellulose carbamate were not miscible, showing globular morphologies, whereas high-molar and side chains containing polysaccharides such as xanthan or tragacanth gum form co-continuous morphologies. The forming of blend fibres was nevertheless possible for all three solvents. The textile-physical properties of the blend fibres were slightly decreased compared to those of the unmodified fibre, in which fibres from NMMO and EMIMac had the highest performance. The presence of blended polysaccharides in the fibres produced was verified by residue sugar analysis, in which the highest amounts occurred for EMIMac fibres.
In this paper, the results of research on the bacteriostatic efficacy of selected silver particles: nano-Ag, sub-micro-Ag, AgCl in the finishing of textiles are presented. Thes hapeand size of the silver compounds used were estimated by analysis of SEM images. The size and size distribution of the silver compounds were also approximated by the Dynamic Light Scattering method (DLS).The experiments prove that the antibacterial treatment of textile fabrics by the padding-squeezing technique using silver compounds in the resin matrix can be easily achieved. SEM images of the silver-finished fabric sindicated that, generally, silver compounds were well dispersed on the fabric surface, but in some cases they form agglomerates of single particles. The Agar Diffusion Test was used to estimate the biological activity of the treated fabrics. Two strains of bacteria: Gram-positive (Bacillus subtilis) and Gram-negative (Escherichia coli) were used for this purpose. The washing fastness of Ag-inishedtextileswasmonitoredusingtwomoderninstrumentalmethods:ICP-OESandLA-ICP-TOF-MS. The results obtained proved the good and long-lasting bacteriostatic efficacy of silver nano particles applied during the finishing of cotton.
The world market of dressing materials is being systematically enriched with new products. The raw materials used for dressing manufacture have been modified, the structure of products has been changed, and new kinds of finishes have been applied. A great number of research works have been devoted to demonstrating that chitin, a natural polysaccharide which is a waste material in seafood processing, has many features suiting it for the manufacture of excellent dressing materials. As chitin is characterised by limited processing possibilities, a range of chitin derivatives has been developed. One of them is an ester chitin derivative named dibutyrylchitin, which can be easily dissolved in common solvents. This paper presents a new method of manufacturing nonwoven products made from dibutyrylchitin, which will be applied with the aim of obtaining dressing materials. The technology proposed is based on fleece manufacturing directly from the polymer solution using electrospinning (e-spinning) technology. The proposed method allows fibres of transverse dimensions of below 0.4 μm to be obtained.
This paper presents an investigation into the influence of the parameters of the thermal stabilisation process of polyacrylonitrile (PAN) nanofibres on the process of their pyrolysis. The manufacture of precursor nanofibres by electrospinning from a polyacrylonitrile/N, N-dimethylformamide (PAN/DMF) solution is also described. The diameters of the nanofibres obtained are within the range of 640 nm, whereas their degree of crystallinity, as determined by means of wide angle X-ray scattering, is 40%. The parameters of the thermal stabilisation and the pyrolysis processes of the precursor nanofibres are presented. Two processing variants of the thermal stabilisation of PAN nanofibres in an air stream were applied. The first variant of the stabilisation process was conducted at 225°C for 5-6 h, and the second variant step-wise for 9-10 h in a laboratory chamber dryer at a temperature of up to 280°C. The pyrolysis process was carried out in a thermobalance at a temperature of up to 700°C. Images of PAN precursor nanofibres and of the carbon fibres obtained from them are illustrated by SEM microphotographs.
In order to develop the concept of a new weaving loom, the well known method of shed formation along the warp was used, in which the shed is formed with the use of sinkers positioned on the circumference of a rotating drum, as this method allows to achieve the highest possible frequency of shedding. According to the new concept, in order to beat the wefts to the edge of the fabric, the same sinkers are used as the shed formation, significantly simplifying the loom construction. Inserting wefts into the shed is done with the use of yarn grippers which are placed along the warp width in tunnels formed by the same sinkers that form the shed The gripper v motion is forced by the action directed on the sinkers' walls placed on the drum circumference along a line askew in relation to the drum axis. Such a novel way of inserting the weft is characterised by a simple construction and requires only a small driving energy, and furthermore works quietly. Contrary to hitherto known looms, with construction solutions which require some complex mechanisms (forming the shed, inserting the weft, and beating the weft), all these functions are performed in the loom according to the new Concept as a result of the drum rotation.
The mathematical models of the strength of fancy yarns with continuous effects (plied two- and three-component yarns and loop yarn) were developed on the basis of the mechanical rules, phenomena occurring between the staple fibres in the component yarns and the final structure of fancy yarns. Three types of distribution of the length of the staple fibres (steady, trapezium and normal) and two types of fibre migration (full migration and lack of migration) were considered Experimental verification was conducted and the larger influence of the distribution of the fibres' length than the migration of fibres on the strength of the final fancy yarns was proved. The essential influence of the component yarns' tensions during the twisting process on the structure and strength of fancy yarns was shown.
The article presents initial research into the structure and working conditions of textile thermocouples used as temperature sensors. Textile thermocouples differ from traditional ones, not only in the kind of materials used for manufacturing both thermoelectrods, but also in the construction of the electrodes themselves and the measuring junctions. Within the scope of this work, different kinds of textile thermocouples were tested and their incremental thermometric characteristic determined.
The use of cellulolytic enzymes in the process of cellulose biomodification is one of the current applications of these enzymes which allows us to join the process of controlled partial cellulose degradation with changes to the molecular, supermolecular, and morphological cellulose structure. The application of biotechnological methods in the chemical fibre industry allows us to solve problems connected with protecting the natural environment. This paper presents the results of investigations concerning the estimation of the usability of cellulolytic enzymes created by the Aspergillus wentii ŁOCK 0459 strain used for modifying cellulose pulps. The tests were carried out with the use of an Aspergillaceae strain from the Polish Culture Collection (Kolekcja Czystych Kultur) at the Technical University of Lódź. Biomodified cellulose pulps, characterised by a solubility of 98% in aqueous solutions of sodium hydroxide, were used for the preparation of alkaline cellulose solutions. The solutions obtained were applied as spinning solutions for the process of cellulose fibre and film formation.
Polyamide fibres initiated by γ radiation of 4.5-13.5 kGy doses and grafted with acrylamide were examined by 1HNMR spectroscopy to determine the position of the active centre formed in the polyamide fibre. The results of the experiment show that certain changes in the structure of the polyamide fibre are caused by radiation and acrylamide grafting. Futhermore, it may be presumed that the generation of active centres and polyacrylamide grafting in the PA6 chain takes place on the nitrogen atom of the amide groups. This has been confirmed by a broadening of the absorption bands of methylene groups adjacent to the nitrogen as well as by the absence of new absorption bands, of methine groups for instance. The latter should appear if the active centre was formed on other atoms of the polyamide chain and if grafting took place in this particular position.
The thermal property of fabric is very important for both its thermal comfort and protection against challenging weather conditions. Although some research has reportedly been done on the dimensional and some of the mechanical properties of rib knit fabrics, no detailed study about the thermal properties of rib knit fabric could be seen. In this study, the natural and forced convective heat transfer characteristics of rib knit fabric have been analysed. The effect of rib design and other fabric properties such as fabric density and air permeability on thermal behaviour have been considered It has been noted that a decrease in rib number of the order of 3x3, 2x2 or 1x1 leads to a decrease in heat loss due to an increase in the amount of air entrapped between the face and the back loop. The results also indicated that as the fabric gets tighter so the heat loss lessens, due to reduced air permeability, i.e., reduced air circulation within the fabric. Thus, it results that when the fabric design (1x1 rib, 2x2 rib, 3x3 rib, etc) is taken into consideration, the conductive heat loss due to fibres and air gaps becomes more important than the heat loss due to air circulation (convective heat loss). However when the fabric density for each fabric design is taken into consideration, the heat loss due to air circulation (convective heat loss) becomes more important than the conductive heat loss due to fibres and air gaps.
In the copolymerisation of acrylonitrile (AN) with methyl methacrylate (MM) in N,N-dimethylformamide (DMF) initiated by 2,2′-azoisobutyronitrile (AIBN), that is, in the system AN(A)MM(B)/DMF(S)/AIBN(I)/60°C, the solvated forms of the initiator exist as follows: AIB, IB, BIS, AIS, SIS, and AIA. An analysis of the course of the dependencies of the relative contributions of these forms on a concentration of the monomer mixture (C=A+B in molxdm-3) was performed. The contents of the solvates AIB, IB and AlA were found to increase with the increase of C; the dependencies of the solvate contents BIS and AIS are characterised by the curves possessing a maximum, whereas the amounts of the solvate SIS decrease when increasing the concentration C. The dependencies of the relative contributions of solvated forms occurring in the system on the monomer mixture composition [xA=A/(A+B)] were also analysed. A decrease of the contents of the solvates IB and BIS with an increase of xA was found; the dependence of the solvate content AIB is characterised by the curve possessing a maximum, whereas the remaining solvates (AIS, SIS, AIA) exhibit an increase of the relative concentration, although the numerical values of their contents are small. This information permits the programming of the conditions of the copolymerisation (concentration C and composition xA of the comonomer mixture) under which the presence of selected solvates will be preferred.
This article attempts to analyse the emerging opportunities and threats connected with the new environment in which Polish enterprises started to operate after 1 May 2004. It also presents the conclusions that Polish protective clothing manufacturers can draw. In this context, we discuss the most recent trends in protective clothing manufacturing, as well as the newest management and marketing tendencies resulting from the need to adjust marketing operations to the evolving environment. The article is not limited to analysis of the supply-side of the Polish protective clothing market. A separate discussion is devoted to the effects of EU enlargement on the situation of protective clothing buyers, with emphasis on adjusting the Polish law to EU industrial safety regulations. In addition, the article discusses the economic aspects of implementing EU industrial safety requirements.
This article presents a short characteristic of soybean protein fibres and the perspectives for their development and applications, especially from the point of view of China as their producer.
This paper presents a virtual design process for a tight-fitting garment pattern for adapted consumer garments, aimed at consumers with scoliosis. The design process proposed is based on a virtual human model created using a 3D scanner, allowing simulation of the morphological shape of an individual with atypical physical deformations. Customized 2D and 3D virtual garment prototyping tools are used in combination to create products through interactions between the consumer, designer and pattern maker. After following an interactive sequence: Scanning – Design – Display – Evaluation – Adjustment, a final design solution acceptable to both the designer and consumer can be obtained. Through this process, traditional 2D garment design knowledge, especially design rules influenced by the fabric information, is fully utilized to support the design process proposed. Using the knowledge based collaborative design process, design satisfaction can be largely improved.
On the basis of computer image processing analysis, we carried out an assessment of selected knitted fabrics' structure properties by establishing the density of double-layer plain knitted fabrics and plain stitch fabrics. It was noted that the values of correlation ratios between the proposed computer method and the standard method indicate the commensurability of both methods.
The process of individualizing personal protective equipment (PPE) is aimed at achievingoptimal fit to the user’s body, thus maximizing comfort, especially when PPE is applied in critical conditions. The aim of the research was to confirm the possibility of implementing PPE in rea industrial conditions and to estimate the comfort of use in real conditions of use. In order to perform the last stage of the personalization procedure for firefighter suits, process qualification was carried out in an industrial environment, and the firefighter’s PPE fabricated was validated under real conditions of firefighters’ activities. The effect of implementation of the individualization procedure confirmed optimal fitting of the PPE to the individual user’s body and allowed for improvement of the comfort of use.
The work comprises a statistical tolerance analysis of human body dimensions using a 3D body scanner and its impact on the value of unit pressure exerted by a compression product on the subject’s body. Model calculations of changes in unit pressure due to the susceptibility of the human body were carried out on the basis of the Laplace law using experimentally determined values of circumferences of particular parts of a female subject, with and without a compression product. Experimentally documented changes in the body circumferences under the influence of a compression garment are one of the reasons for the differences between the intended and actual pressure value exerted by the product.
A stab resistant vest is a reinforced piece of body armour designed to resist knife or needle attacks of different energy levels specifically to the upper part of the body (chest and abdomen) to save lives. The majority of armours limit several comfort parameters, such as free locomotion, respiration, flexibility and light weight, which determine efficient use by wearers and their willingness to wear. Currently available armours are usually made of a single plate, and although often segmentation is used with just a few but still quite large pieces, the materials are compact and bulky to wear. In this study, stab protective armor elements (scale-like elements) of 3 mm thickness and 50 mm diameter were designed, produced (3D printed) and tested for performance. Aramid fibre was used for its strength, durability and process ability to develop protection elements at unidirectional and multidirectional filling angles during 3D printing. The specimens were tested according to VPAM KDIW 2004. The specimens designed and developed with multidirectional filling angles of aramid resist the puncturing energy level K1 (25 J) with a penetration depth less than the maximum allowed for the K1 energy level by VPAM. These specimens showed a high protection level of relative small thickness (3 mm) and light weight (6.57 grams for the estimated area A ≈ 1963.5 mm2) as compared to the currently certified armors for K1 (for example, the aluminum mass is 13.33 grams for 2 mm thickness and 50 mm diameter).
This article presents a geometrical model of three – and five – layer 3D distance knitted fabric which characterises the structural features of the fabric in a spatial Cartesian xyz system. New notions (technical terms) of 'spatial a – jours' and 'spatial reliefs' are intro-duced. Spatial a – jours are channelled layer structures inside knitted fabrics, whereas spatial reliefs are characterised by a different structure of the internal, as well as external layers, which are the result of a different thickness of the fabric layer's segements. A hybrid model was developed of the graphical description of a 3D distance knitted fabric. This model includes a description of the thread continuum in the fabric stitch using of the 2D system. Whereas considered a solid, it presents the spatial architecture of the knitted fabric. The model composition was verified by an analysis of the real structures of twenty stitch variants.
During the first stage of our considerations, a model of the compression process of a 3D distance knitted fabric was related to a single connector fastened to it by articulated joints, and considered as a slender rod with an assumed shape. In our physical and mathematical models, the compression of a slender, elastic rod was based on assumptions concerning the knitted fabric's morphology, as well as the mechanical properties of the threads particularly monofilaments placed in the internal layer of the fabric. A calculation method was developed which enables to determine the functional dependencies between the compressing force and bending deflection, as well as a method of determining curves representing the shape of the compressed rod-connector A computer simulation of the compressed rod Connecting the two outside layers of the knitted fabric, considering the variable parameters of the model, was carried out with the use of calculation algorithms elaborated by us, and MathCad program.
The purpose of this paper was to develop an individual prototype garment pattern based on 3D body scanning data. Firstly, the cross-sections of scanning data were preprocessed by three methods, including re-sampling, symmetrising and convex hull calculating. Secondly, NURBS modeling technology was adopted to create a basic garment model based on the curve network. According to different traditional flat prototype patterns, the corresponding feature lines are defined on the models through calculating the intersection curves of the body surface and local planes. Finally, three 3D garment models were subdivided by different cutting methods and the advancing front triangulation method. Surface flattening based on the energy model was adopted to generate the corresponding 2D patterns. In order to analyse the error, the area and length of the 3D and 2D patterns were calculated and compared, respectively, the results of which promote the practicability of the 2D pattern design system in MTM garment production through 3D CAD technology.
The article describes the construction and testing of a functional model of an innovative warp – knitting machine for technical spatial knitted fabrics with an original structure. Design assumptions regarding the geometrical, kinematic and driving characteristics of the machine are described. The functional model as well as its physical implementation as a research stand are presented. The production phases of the 3D knitted fabric are also demonstrated. The research results are described and their importance for the construction of a machine prototype of the production version are emphasised.
The article presents the results of strength tests of thin-walled composite beams carried out with the use of the thermovision technique. During a beam bending test performed in a four-point support system using a testing machine, an increase in the value of the temperature on the surface of the beam was observed along with an increase in the bending input function (deflection of the beam). The curve of force (stress) is correlated with curves of changes in the values of heat emitted during the bending process. The maximum value of temperature rise of the bending composite reaches the value of ΔT = 20.02 °C. The process of the bending of a beam is accompanied by a conversion of mechanical energy into free surface energy, thermal energy as a result of damaged atomic and intermolecular bonds, and also thermal energy occurring due to friction force acting between the destroyed surfaces. The experiments carried out confirm the thesis that analysis of the temperature distribution of composites in strength tests is the basis for the quality evaluation of stress distribution in the composites tested.
The object of the publication is to present the validation process stage (operational qualification) of developed assumptions for customised clothing manufactured in industrial conditions. 12 special clothes were made and adjusted to the individual dimensions of firefighters’ silhouettes obtained in the 3D scanning process as well as 12 special clothes adjusted to selected size subgroups after the 3D scanning process from the same identified group of 12 firefighters. Two batches of clothes having undergone the installation qualification were submitted for testing in real conditions (operational qualification). Then, on the basis of data collected from the ongoing functional tests, a batch of six sets of individualised special clothing for the Fire Service was produced in industrial conditions (changing the manufacturer and model of the clothing). A positive result of validation (operational qualification) of this batch of clothing in functional tests conducted in real conditions will allow its introduction to industry through training in production plants and procedures of individualisation of advanced protective clothing design for people working in environments with a high degree of risk to health and life. The individualisation of protective clothing design, through a better fit of the size of the clothing to the body of the user, will significantly affect the comfort of use, ergonomics of the clothing, and the safety of the user.
A model of the compressing process of a 3D distance knitted fabric was related to a single connector fastened on one side by an articulated joint, as well as fastened on both sides by fixed joints, considering the connector as a slender rod with an assumed shape. The compressing of an elastic rod in the physical and mathematical models was based on assumptions considering the morphology of the knitted fabric as well as the mechanical properties of threads – monofilaments placed in the internal layer of the knitted fabric. Calculation methods and algorithms were developed for the determina-tion of the functional dependencies between the force compressing the knitted fabric and deflection, as well as the description of the curves representing the shape of the compressed rod. A computer simulation of compressing the rod, which connects both outside layers of the knitted fabric, was carried out with the use of the 'Mathematica' program, taking into consideration the variable parameters of the model. The consid-erations carried out in this article are significantly based on our previous publication, and therefore the assumptions of the physical model and detailed descriptions of the analysis are not included.
A parametric study is presented of 3D woven fabric's internal structure parameters. The study was carried out with a CETKA software package, allowing any simulation of woven fabric structures for given 3D weave pattern, yarn properties, and weave tightness. The parametric study shows the posibilities to control 3D fabric properties by the choice of yarn parameters, this achieving a broad range of variation of fabric porosity for a given weave structure. The porosity of 3D fabric varies strongly within a given fabric volume; the complex spatial pore distribution is important for filter and composite materials applications of 3D woven fabrics.