Search

Due to the particular physiological conditions of the human body, activity in cold weather condition is of great importance and needs unique thermal clothing. In this research, three-layered heating fabrics were designed and woven to analyze their performance in cold climates. The samples consist of three types of heating elements (nickel-chrome, tungsten, and aluminum-chrome) and two different states for embedding the heating elements in the fabric structure. In order to investigate the effect of voltage on the heat flux and maximum temperature, all specimens were subjected to two voltage levels of 9 and 12 V for 10 min, the process of heat production, the influence of structural factors on the flux and temperature and also the thermal efficiency was analyzed. In addition, in order to select the optimum sample, the amount of required energy for maintaining body comfort was calculated based on the theoretical equations at the ambient temperatures of −5 and −10°C. The results showed that the woven sample using tungsten elements and the weft-to-element ratio of 12 had the desirable heating performance and could maintain the skin surface temperature around the thermal comfort zone.

The behavior of the material against the external forces depends on its mechanical properties, including strength, elastic modulus, fatigue behavior, and so on. Of these properties, the elastic mod...

In tissue engineering, the structure of nanofibrous scaffolds and optimization of their properties play important role in the enhancement of cell growth and proliferation. Therefore, the basic idea of the current study is to find a proper method for tuning the extent of porosity of the scaffold, study the effect of porosity on the cell growth, and optimize the extent of porosity with the aim of achieving the maximum cell growth. To tune the scaffold’s porosity, four types of metal mesh with different mesh sizes were employed as collectors. For this purpose, the structural properties of polycaprolactone nanofibrous layers which were electrospun on collectors, and the level of neural A-172 cell growth on layers were investigated, and the results were compared with the results attained for the fabricated nanofibrous layer on a flat aluminum collector. It was found that upon changing the porosity of the metal mesh as collector, the fibers’ diameter would be inevitably changed, albeit insignificantly, and following no specific trends. However, changing the mesh size has shown a significant effect on the thickness and porosity of nanofibrous layer. According to the MTT assay results, the optimum neural cell growth was observed for the electrospun nanofibrous scaffold with the porosity of 96% and pore size of (0.42–23 µm) which has been fabricated on the type-4 collector having a mesh size of 10. The fabricated scaffold using this mesh with the optimum extent of porosity (58%) resulted in 44% enhancement in the cell growth as compared with the fabricated layer on the flat collector.

Application of electrospun nanofibrous scaffolds has received immense attention in tissue engineering. Fabrication of scaffolds with appropriate electrical properties plays a key role in neural tissue engineering. Since fibers orientation in the scaffolds affects the growth and proliferation of the cells, this study aimed to prepare aligned electrospun conductive nanofibers by mixing 1 %, 10 % and 18 % (w/v) doped polyaniline (PANI) with polycaprolactone (PCL)/poly lactic-coglycolic acid (PLGA) (25/75) solution through the electrospinning process. The fibers diameter, hydrophilicity and conductivity were measured. In addition, the shape and proliferation of the nerve cells seeded on fibers were evaluated by MTT cytotoxicity assay and scanning electron microscopy. The results revealed that the conductive nanofibrous scaffolds were appropriate substrates for the attachment and proliferation of nerve cells. The electrical stimulation enhanced neurite outgrowth compared to those PLGA/PCL/PANI scaffolds that were not subjected to electrical stimulation. As polyaniline ratio increases, electric stimulation through nanofibrous PLGA/PCL/PANI scaffolds results in cell proliferation enhancement. However, a raise more than 10 % in polyaniline will result in cell toxicity. It was concluded that conductive scaffolds with appropriate ratio of PANI along with electrical stimulation have potential applications in treatment of spinal cord injuries.

Surface friction of fabrics is one of the prominent tactile properties which influence the comfort and application of clothes. In this paper, a new approach is proposed to characterize the surface ...

The complex nature of spinal cord injuries has provided much inspiration for the design of novel biomaterials and scaffolds which are capable of stimulating neural tissue repair strategies. Recently, conductive polymers have gained much attention for improving the nerve regeneration. In our previous study, a three-dimensional (3D) structure with reliable performance was achieved for electrospun scaffolds. The main purpose in the current study is formation of electrical excitable 3D scaffolds by appending polyaniline (PANI) to biocompatible polymers. In this paper, an attempt was made to develop conductive nanofibrous scaffolds, which can simultaneously present both electrical and topographical cues to cells. By using a proper 3D structure, two kinds of conductive scaffolds are compared with a non-conductive scaffold. The 3D nanofibrous core-sheath scaffolds, which are conductive, were prepared with nanorough sheath and aligned core. Two different sheath polymers, including poly(lactic-co-glycolic acid) PLGA and PLGA/PANI, with identical PCL/PANI cores were fabricated. Nanofibers of PCL and PLGA blends with PANI have fiber diameters of 234±60.8 nm and 770±166.6 nm, and conductivity of 3.17×10-5 S/cm and 4.29×10-5 S/cm, respectively. The cell proliferation evaluation of nerve cells on these two conductive scaffolds and previous non-conductive scaffolds (PLGA) indicate that the first conductive scaffold (PCL/ PANI-PLGA) could be more effective for nerve tissue regeneration. Locomotor scores of grafted animals by developed scaffolds showed significant performance of non-conductive 3D scaffolds. Moreover, the animal studies indicated the ability of two new types of conductive scaffolds as spinal cord regeneration candidates.

In this paper, nylon 66/TiO2 composite nanofiber yarn has been developed using electrospinning method. The effect of the TiO2 nanoparticle content on the physical and tensile properties of the resulted composite nanofiber yarns has been extensively investigated using SEM, EDX, FTIR and mechanical testing machine. The probability density function is computed to model the diameter distribution of nanofibers constituent of the composite yarn for different percentages of TiO2. The addition of TiO2 nanoparticles into the electrospun composite nanofiber yarn decreases its tensile strength. The influence of thickness (diameter) and twist of the yarn on its tensile strength has been considered and the optimum conditions with improved tensile strength have been presented. Photoactivity of the composite yarns is tested against Rhodamine B (RhB). Results show that nanocomposite yarns are effective to be used as an economically and environmentally friendly photocatalyst in water remediation processes. They are not dispersed in the solution and can be removed easily without additional and costly steps of filtration or centrifuge.

Selection of the best possible filter set among a set of available filters is the obvious method of increasing dimension of camera signals for spectral reflectance reconstruction. There are also methods that are focusing on the filter design regardless of noticing to the constructability of the designed filters. This study shows that direct optimization of physical variables of filter manufacturing technique is more reliable than indirect approach of designing and then physical manufacturing of the designed filters. Direct optimization of the transmission-controlling primaries in filter manufacturing process would guarantee having the designed filters in reality. Combination of some solvent dyes was used as the spectral transmission matching system for filter manufacturing. As a conventional technique, filters were designed and best possible dye concentrations that match the desired filters were calculated. As an alternative approach, filters were also designed using direct optimization of dyes concentrations. The results showed that direct optimization of dye concentrations exhibits better performance in comparison with the conventional technique. © 2016 Wiley Periodicals, Inc. Col Res Appl, 2016

Nanotopography and stiffness are major physical cues affecting cell fate. However, the current nanofiber modifications techniques are limited by their ability to control these two physical cues irrespective of each other without changing the materials' surface chemistry. For this reason, the isolated effects of topography and stiffness on osteogenic regulation in electrospun nanofibers have been studied incompletely. Here, we investigated 1. how functionalized multiwall carbon nanotubes (F-MWCNTs) loaded in Polycaprolactone (PCL) nanofibers control their physical properties and 2. whether the resulting unique structures lead to distinctive phenotypes in bone progenitor cells. Changes in material properties were measured by high-resolution electron microscopes, protein adsorption and tensile tests. The effect of the developed structures on human mesenchymal stem cell (MSC) osteogenic differentiation was determined by extensive quantification of early and late osteogenic marker genes. It was found that F-MWCNT loading was an effective method to independently control the PCL nanofiber surface nanoroughness or stiffness, depending on the applied F-MWCNT concentration. Collectively, this suggests that stiffness and topography activate distinct osteogenic signaling pathway. The current strategy can help our further understanding of the mechano-biological responses in osteoprogenitor cells, which could ultimately lead to improved design of bone substitute biomaterials.

Today nanofibers are used widely in a variety of applications. Among many investigations of nanofiber characteristics, their color features have been studied scarcely. In this study, nanofiber yarns were colored using two different methods: exhaustion dyeing and colored solution electrospinning or dope dyeing. In the first method, nylon66 nanofiber yarns were produced and then dyeing process was followed at different dye concentrations. In the second method, colored nanofiber yarns were produced directly using the yarn electrospinning setup. Through the spectrophotometric measurements, it was illustrated that the color saturation increases by increasing the dye content in the dyeing bath and electrospinning colored solution. At the end, the nanofiber yarns with equal dye content were produced using two mentioned methods. It was observed that the color strength of dope-dyed samples was lower than the dyeing process samples, but their levelness was better than the samples of dyeing process. Chromatic values...

Achieving whiteness and opaqueness has been an issue in paint, ceramic, paper, and coating industries from the very beginning. In the past two decades, biomimetics, for the construction of bio-inspired functional materials, has attracted much attention. As an application of biomimetic science, various structural colored materials are investigated by many researchers. The white beetle exoskeletal scales is one of those materials that shows a brilliant white color caused by randomly arranged chitin nanofibers. This material is the inspiration for achieving light weight, efficient, and low-cost white coatings by means of a nanostructure. We used this idea in this research to apply nanofibrous polymeric layer on a substrate, paper sheet in here, and witnessed the possible achievements by varying the nanofiber layer characteristics that underpin its optical properties. We coated nylon and PAN nanofiber layers on the surface of a paper using an electrospinning method and for both polymers desirably high whiteness and opaqueness achieved. Moreover, it was observed that end-use application in printing and writing is easily attained on the nanofiber-coated paper using the common methods. Measuring the properties of the nylon nanofiber-coated paper showed that the tensile strength and hydrophilicity slightly increased depending on the nanofiber layer characteristics.

In this paper, a new approach is proposed for characterizing the surface roughness of woven fabrics. This approach is based on the fringe projection moire techniques and analysis of the moire pattern, which is caused by the interaction between the Ronchi grating and the periodic structure of a woven fabric. In this study, an image processing procedure was employed and a new parameter called the “roughness index” was defined for quantifying the surface roughness. The results obtained from the moire technique were validated by a set of pair-comparison subjective tests. The proper correlation, with an average R-squared value of 0.9087, between subjective and objective tests confirmed the accuracy, correctness and efficiency of the new method. Statistical analysis of the roughness results clarified that the effect of fabric structural parameters such as the weave structure and weft density is significant in the confidence range of 95%.

In this study, a new approach is proposed to represent a model for heat transfer through a fabric containing microcapsules of phase change materials (micro-PCM). It is observed that the phase change phenomenon occurs within a melting temperature zone where the temperature is not constant. Based on this fact, during phase change process, the heat capacity of fabric which is comprised of constant and temperature dependent elements is changed. A variation function extracted from DSC results is applied to calculate the temperature dependent heat capacity of fabric. The model is applied to study the transient effect of PCM on a simulated skin temperature system once subjected to abrupt changes in environmental conditions from warm to cold. The values of Tmean are 0 and 4.6 for sample without PCM and sample containing maximum PCM with nominal melting point of 28 °C, respectively. |GT| are 32.51 and 139.2 for corresponding samples. The model was further verified by the effect of PCMs existence and PCM type on the temperature response of simulated skin.

Considering the efficient TiO 2 structure on enhancing its photocatalytic behavior is of great interest in recent years. Meanwhile, inhibiting the filtration process for detachment of the catalyst from the purified solution is very advantages. To approach this purpose, TiO 2 nanofiber yarns were successfully fabricated through the electrospinning technique using two oppositely charged nozzles followed by the calcinations process from a solution containing titanium precursor and polyvinyl acetate (PVAc) as the supporting material. The introduced nanofiber yarns eliminate the ultrasonic and centrifuge steps required in photocatalytic tests of nanoparticles and electrospun nanofibers. The results show that this new catalyst's structure maintains its shape during the photocatalytic degradation process and can be easily removed from the purified water.

Electrospun nanofiber matrices are widely used as scaffolds for the regeneration of different tissues due to similarities with fibrous components of the extracellular matrix. These scaffolds could act as a substrate for inducing mechanical stimuli to cells. The main mechanical stimuli factor in nanofiber scaffolds for determining the cell behaviors is stiffness of single nanofibers. This paper especially highlights the finding that the young's modulus of single nanofibers can be obtained from aligned nanofibers matrix. It is assume that, the modulus of single nanofibers are equal to modulus of completely aligned nanofibers. However, due to difficulty of producing completely aligned nanofibers, the obtained modulus of single nanofiber wouldn’t have significant value. Therefore, we propose a new mathematical model to predict the stiffness of single nanofibers from non-perfectly aligned nanofibers matrix.

Nanomedicine is a growing research area dealing with the engineering of materials at a nanometer scale for the improvement of treatment, diagnosis, and imaging of diseases. In medicine and therapeutic applications, the use of nanostructures, such as nanofibrous materials and nanoparticles as drug-delivery systems has improved the bioavailability, intestinal absorption, solubility, sustained and on-demand drug release and targeted delivery, and, more importantly, therapeutic effectiveness of anticancer agents. The expansion of novel nanoparticles and nanofibrous structures for targeted drug delivery is an exciting and challenging research field, in particular for the delivery of emerging cancer therapies. Electrospinning, as an interesting producing approach for nanostructures, is a straightforward and robust method to fabricate nanofibers with the potential to incorporate drugs and therapies agents in a simple and reproducible process. In addition, a broad range of drugs, from antibiotics and anticancer agents to proteins, aptamer, DNA, and RNA, have been incorporated into electrospun fibers. This chapter emphasizes on an emerging area using the electrospinning technique to generate biomimetic nanofibers and nanoparticles as drug delivery devices that are responsive to different stimuli, such as temperature, pH, light, and the electric/magnetic field for controlled release of therapeutic substances. In addition, the promising use of electrospun nanofibers and nanoparticles with extracellular matrix morphology and intrinsically guiding cellular drug uptake, which will be highly desired to translate the promise of drug delivery for clinical success, is scrutinized for different treatment strategies.

In this work, a dynamic system has been developed to evaluate the thermal behavior of fibrous layers containing PCM 1 . The system is able to concurrently resemble the triple condition of ‘human body–clothing layers–environment’. The system hotplate, acting as the metabolic heat generator of human body, is able to self-adjust depending on the activity level of body section. An adjustable layering unit has been placed on the hotplate to simulate clothing layers. The environmental condition was rapidly changed from 0 to beyond 60 °C and from 5 to 100% relative humidity in order to prepare a transient condition. On-line data acquisition software has been designed to record and monitor data of the upper hotplate (skin) and spaces between the fibrous layers. Two indices were introduced and extracted to represent the thermal behavior of body skin/layers in the presence of PCMs at different environments. The system was further verified by studying the effect of PCMs presence and their increase on the thermal behavior of body skin/fibrous layers. The effect of PCMs’ melting point, during thermal transient, was finally presented by the system.

The different aspects of fabricating continuous TiO2 nanofiber yarns using oppositely charged metallic nozzles are studied. The importance of a proper auxiliary polymer, solvent and process required for continuous yarn formation are considered as effective process factors and are studied. Practical studies on solution concentration of the proposed polymer and solvent showed that it plays a significant role in the continuous electrospinning of nanofiber yarns and the diameter of nanofibers contained in the yarns.

The demand for novel antibiotic-loaded electrospun nanofibrous structures has increased extremely in the recent years and has engaged the interests of scientists and engineers into a blend configuration of antibiotic drug and biocompatible polymers due to their unique applications in future of better therapeutic effect, reduced toxicity and sustained local antibiotic release over a period of time. One method to produce these antibiotic-loaded networks is by electrospinning process. However, it is very important to know structural characteristics and morphology of nanofibers for controlling the performance of the yields. In this paper, fabrication of electrospun nanofibers suited for antibiotic delivery system is investigated based on tetracycline hydrochloride as the antibiotic drug and poly (lactic-co-glycolic acid) as the biodegradable polymeric matrix. Furthermore, the effect of material and process parameters on morphology and release behavior of produced nonwovens is investigated. The efficacy of the medicated scaffolds using a static system for bacterial growth on agar plates was also proved.

Scaffold design has a critical role in tissue engineering as scaffold features affect cell attachment and proliferation. Size scale similarities of electrospun nano-/microfibrous scaffolds with a native extracellular matrix have been appealing for tissue engineering applications and numerous studies have investigated the effect of different aspects of nano-/microfibrous scaffolds such as fiber diameter, thickness of nano-/microfibrous scaffolds on cell behavior. In this study, electrospun poly (ϵ-caprolactone) (PCL) microfibrous scaffolds were fabricated with nanosized pores on the surfaces of fibers created by the electrospinning of PCL solution with a highly volatile solvent in a humid ambient and the effects of nanopores on the attachment and proliferation of epithelial kidney cells (Vero) and mesenchymal stem cells (MSCs) were investigated. Morphology and hydrophilicity of the scaffolds were analyzed by scanning electron microscopy (SEM) and the video contact angle system and evaluation of cells proli...

In this paper changes in the appearance of 100% cotton ring spun yarns due to several yarn-to-yarn abrasion cycles before rupture are characterized. Different pictorial indexes for four different yarn counts are evaluated. The process of abraded yarns is defined by image processing techniques. The comparison between the indexes found that the weight loss of yarns at each step is performed using linear regression analysis to introduce the most appropriate index for quantifying the yarns’ abrasion. The mean value of diameter index which is related to the changes in yarn core shows the highest correlation with weight loss. This method enables studying the yarn-to-yarn abrasion behavior before rupture more accurately and rapidly for quality control purposes.

Since spinal cord injury is a complicated problem, neural tissue repair, and regeneration strategies have received a great deal of attention. In this study, a three-dimensional (3D) nanofibrous core-sheath scaffold with nanorough sheath and aligned core were fabricated by a combined electrospinning method with water vortex and two-nozzle system. In vitro and in vivo biological tests were carried out on the poly(lactic-co-glycolic acid) (PLGA) scaffolds. The cell morphology and proliferation evaluation of nerve cells on 3D PLGA scaffolds were studied. Cells were properly orientated along the aligned fiber direction of the scaffold. In animal studies, adult rats received a complete lateral hemisection at the T9-T10 level. Scaffolds were engrafted to bridge 3 mm defects of 10 adult rat spinal cords; 10 rats were used as controls. For 8 weeks, motor and sensory recovery by open field locomotor scale, narrow beam and tail flick tests were assessed. Locomotor and sensory scores of grafted animals were significantly better than the control group. Histological findings demonstrated that the scaffold supports the axonal regeneration of injured spinal cords and regenerating axons were seen to enter the graft and extend along its length.

Electrospinning has been recognized as an efficient technique for the fabrication of neural tissue engineering scaffolds. Many approaches have been developed on material optimization, electrospinning techniques, and physical properties of scaffolds to produce a suitable scaffold for tissue engineering aspects. In this study, structural properties of scaffolds were promoted by controlling the speed of fiber collection without any post-processing. PLGA scaffolds, in two significantly different solution concentrations, were fabricated by the electrospinning process to produce scaffolds with the optimum nerve cell growth in a desired direction. The minimum, intermediate and maximum rate of fiber collection (0.4, 2.4, 4.8 m/s) formed Random, Aligned and Drown-aligned fibers, with various porosities and hydrophilicities. The scaffolds were characterized by fiber diameter, porosity, water contact angle and morphology. Human nerve cells were cultured on fiber substrates for seven days to study the effects of different scaffold structures on cell morphology and proliferation, simultaneously. The results of MTT assay, the morphology of cells and scaffold characterization recommend that the best structure to promote cell direction, morphology and proliferation is accessible in an optimized hydrophilicity and porosity of scaffolds, which was obtained at the collector linear speed of 2.4 m/s.

Fabrication of core–shell nanofibers by coaxial electrospinning system suited for drug delivery applications was investigated based on tetracycline hydrochloride (TCH) as the core and poly(lactide-co-glycolide) as the shell materials. Comparison of drug release from monolithic fibers (blend electrospinning) and core–shell structures was performed to evaluate the efficacy of the core–shell morphology. The nanofibrous webs are potentially interesting for wound healing purposes since they can be maintained for an adequate length of time to gradually disinfect a local area without the need of bandage renewal. Further, our studies showed the potential of core–shell nanostructures for sustained drug release, which also suppressed the burst release effect from 62 to 44% in the first 3 hours by adding only 1 wt% TCH to the polymeric shell. POLYM. ENG. SCI., 2013. © 2013 Society of Plastics Engineers

Although metric functions that show the performance of a colorimetric imaging device have been investigated, a metric for performance analysis of a set of filters in wideband filter-based spectral cameras has rarely been studied. Based on a generalization of Vora’s Measure of Goodness (MOG) and the spanning theorem, a single function metric that estimates the effectiveness of a filter set is introduced. The improved metric, named MMOG, varies between one, for a perfect, and zero, for the worst possible set of filters. Results showed that MMOG exhibits a trend that is more similar to the mean square of spectral reflectance reconstruction errors than does Vora’s MOG index, and it is robust to noise in the imaging system. MMOG as a single metric could be exploited for further analysis of manufacturing errors.

This paper reports a fast, accurate, and non-destructive three-dimensional imaging approach based on using quantum dots and confocal laser scanning microscopy to get three-dimensional images of internal pore structure of the nanofibrous materials. A practical method of making the fiber fluorescent using quantum dots was applied before three-dimensional imaging by confocal laser scanning microscopy. Fibrous scaffolds with different porosity parameters produced by electrospinning and their three-dimensional pore structure was evaluated by this approach. Furthermore, the introduced approach can be used to measure the pore interconnectivity of the scaffold.

Specific internal pore architectures are required to provide the needed biological and biophysical functions for fibrous scaffolds as these architectures are critical to cell infiltration and in-grows performance. However, the key challenging on evaluating 3D pore structure of fibrous scaffolds for better understanding the capability of different structures for biological application is not well investigated. This article reports a fast, accurate, nondestructive, and comprehensive evaluation approach based on confocal laser scanning microscopy (CLSM) and three-dimensional image analysis to study the pore structure and porosity parameters of Nano/Microfibrous scaffolds. Also a new method of making the fiber fluorescent using quantum dots (QDs) was applied before 3D imaging. Fibrous scaffolds with different porosity parameters produced by electrospinning and their 3D-pore structure was evaluated by this approach and the results were compared to results of capillary flow porometry. The pore structural properties measured in this approach are in good agreement with that measured by the capillary flow porometry (with significant level 0.05). Furthermore, the introduced approach can measure the pore interconnectivity of the scaffold. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 765–774, 2013.

Layered fabric systems with an electrospun nanofiber web layered onto a sandwich of woven fabric were developed to examine the feasibility of developing breathable barrier textile materials. Some parameters of nanofiber mats, including the time of electrospinning and the polymer solution concentration, were designed to change and barrier properties of specimens were compared. Air permeability, water vapor transmission, and water repellency (Bundesmann and hydrostatic pressure tests) were assessed as indications of comfort and barrier performance of different samples. These performances of layered nanofiber fabrics were compared with a well-known water repellent breathable multi-layered fabric (Gortex). Multi-layered electrospun nanofiber mats equipped fabric (MENMEF) showed better performance in windproof property than Gortex fabric. Also, water vapor permeability of MENMEF was in a range of normal woven sport and work clothing. Comparisons of barrier properties of MENMEF and the currently available PTFE coated materials showed that, those properties could be achieved by layered fabric systems with electrospun nanofiber mats.

In the conventional subjective method, wrinkled fabric specimens are visually compared with the standard replicas under a specific light source in order to be evaluated and classified. In the present work, the rank ordering method is incipiently applied for grading a wide range of wrinkled fabrics. The five standard replicas are orderly placed among the ranked specimens and their grades are extracted. Results show that the specimens ranked by the ordering method are reliable and can be used for grading of wrinkled fabric to overcome the problems associated with the standard method such as the limited grading range and high and non uniform intervals between each pair of replicas. Conventional image processing methods used for grading fabric wrinkle are also applied on images taken from the ranked specimens. Among the methods studied in the literature Radon transform, wrinkle paths length and fractal dimension show a good correlation with the wrinkle grades derived from the rank ordering method.

The spectral dependence of the colorimetric characterisation of a typical scanner was investigated. Different colour sets, including ColorChecker SG, Kodak Q-60 colour input target, a set of plain woven coloured fabrics with a large colour gamut, and randomly selected samples of the Munsell Book of Color were used as training and testing sets in the colorimetric characterisation of a scanner by employing a non-linear regression method. The coefficient matrices were optimised for each particular media in the training stage and used to predict the device-independent colorimetric data, i.e. CIELab values of other media from their corresponding RGB values measured by the scanner. In order to extract the differences between the applied sets and determine the actual dimensions of their reflectance spectra, the principal component analysis technique was employed. As expected, it was observed that the different sets benefit from diverse dimensional properties and, in some cases, the spectral behaviours of the first few eigenvectors were apparently different. It was demonstrated that scanner colorimetric characterisation depended on the spectral properties of the applied colour set in the training stage and, consequently, the testing errors increased with increasing the spectral dissimilarity between the sets that were used in training and testing sequences. It was concluded that, to achieve better colour reproduction results, the scanner should be characterised for each media with specific spectral properties.

A new technology based on the liquid support system is introduced for fabricating continuous twisted nanofibrous yarn. In this novel technique, the electrospun yarn was collected from the top of the water vortex such that it can be twisted simultaneously during yarn production. Our study demonstrated the feasibility of the technique for producing continuous twisted yarn from well aligned nanofibers. It is shown that the system can be modified to have different yarn counts with various twists. Further, significant improvement can be seen in the strength and strain when nanofibrous yarn is twisted compared to non-twisted yarn. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers

Pattern generation for carpets is an expensive and time-consuming task that requires skills, imagination, and creativity. In recent years, interactive genetic algorithm (IGA) has been successfully utilized in generating patterns in different fields such as architecture, graphic art, and music among many others. In these applications, fitness functions cannot mathematically be defined, and the fitness value of each pattern combination is required to be evaluated by designer. Therefore, IGA can be utilized to serve as an effective tool to accelerate the design process. In the present work, a modified IGA is developed to generate patterns for machine-made carpets. Each pattern consists of a set of basic elements. Some basic pattern elements are collected, categorized, and coded as gene values. In each generation, new population is formed on the basis of observer's evaluation. All generated patterns are simultaneously shown for observer to assign a fitness value to each one. Hence, a new population can be ach...

This study presents an analytical model to calculate the residual velocity of projectile-penetrating targets composed of planar plain-woven fabric. A non-linear, explicit, three-dimensional finite-element code in ABAQUS 6.4 software is used to simulate the response of plain-woven fabric under high-speed projectile impact. This model is based on single yarn as a backbone component for discritisation. Yarns are modelled as shell elements with elastic behaviour. Non-uniform mesh size is used to achieve computational efficiency and to capture the details of deformation. Interaction between the projectile and the fabric, and between the yarns themselves, considering friction, was determined. Finally, results are compared with other researchers' experimental work to verify the model. Acceptable correlation between results of simulation and experiment is demonstrated in terms of both deformation and residual velocity. The predictive capability and the computational efficiency of the model are quite good.

Knot (pile) formation has a very important role in evaluation and rating of hand-made carpets. Visual identification of carpet structural elements is impossible even for expert people. This research presents a nondestructive method for recognition of carpet knotting structure. It is based on X-ray radiography (mammography). Available X-ray beams create visible images from the internal structure of object in two dimensions. Primary radiological images are taken by radiography from hand-made carpets. They are then converted to structural recognizable images by employing different image processing techniques.

In this paper, the perceptual and instrumental effects of texture on colour is investigated, using 63 textile samples, in nine colour centres and seven texture structures. The effectiveness of texture is evaluated by assessing colour differences between six texture samples and a standard texture in each colour group. Experimental results show that the sample texture has a significant effect on the measured and perceived colour and its influence depends on the colour centre of the sample. The magnitude of texture effect is more dependent on the texture type than on its coarseness. A new term to evaluate texture difference of a pair of textile samples was defined using a Gabor filter (Gabor texture difference). The visual colour changes gave a good correlation with Gabor texture difference values; however, the colour of the samples affected this correlation. So the colour change, as a result of texture differences, depends on two independent variables consisting of the Gabor texture difference and the colour centre of samples.

Capillary rise method was used to determine the surface free energy of 15 different powders. This method is based on measuring the penetration time needed for a liquid to rise to a certain height. The normalized wetting rates as a function of surface tension of the test liquids for a given powder will show a maximum, which is the solid–vapor surface tension of that powder. The powders used covered a wide range of surface free energy (25.5–63.9 mJ/m 2 ). An artificial neural network (ANN) was used to predict the normalized wetting rates for the powders. The network's inputs were particle size, bulk density, and packing density for the powders and surface tension for the liquids. Using the designed and trained network, for each investigated powder, values of surface tension were made to vary in the range of 15.45–71.99 mJ/m 2 (i.e. surface tension range of the available liquids) in increments of 0.01 units and the normalized wetting rates were recorded. The surface tension equivalent to the maximum normalized wetting rate was reported as the solid–vapor surface tension for the powder being investigated. As a result, the individual surface free energy of these powders based on the capillary rise method, was determined without need to obtain the surface tension of each liquid experimentally.

In this research, a new method is used for grading of yarn appearance based on yarn images of ASTM standard (section D 2255), by using an image processing technique and an artificial intelligence technique. In this method, grading of yarn appearance is based on computer vision and analyzing the images of standard pictorial boards of yarn. Therefore this method is very similar to human vision. The logic of the classification by ASTM is considered and then a new definition for classification of yarn appearance grade is presented. In this method of classification, the grading procedure is not dependent on yarn structure and raw materials. Thus it is possible to use this method for grading of any type of yarn based on apparent features.