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Intelligent Recognition of Texture and Material Properties of FabricsWang, Xin 02 November 2011 (has links)
Fabrics are unique materials which consist of various properties affecting their performance and end-uses. A computerized fabric property evaluation and analysis method plays a crucial role not only in textile industry but also in scientific research. An accurate analysis and measurement of fabric property provides a powerful tool for gauging product quality, assuring regulatory compliance and assessing the performance of textile materials.
This thesis investigated the solutions for applying computerized methods to evaluate and intelligently interpret the texture and material properties of fabric in an inexpensive and efficient way. Firstly, a method which allows automatic recognition of basic weave pattern and precisely measuring the yarn count is proposed. The yarn crossed-areas are segmented by a spatial domain integral projection approach. Combining fuzzy c-means (FCM) and principal component analysis (PCA) on grey level co-occurrence matrix (GLCM) feature vectors extracted from the segments enables to classify detected segments into two clusters. Based on the analysis on texture orientation features, the yarn crossed-area states are automatically determined. An autocorrelation method is used to find weave repeats and correct detection errors. The method was validated by using computer simulated woven samples and real woven fabric images. The test samples have various yarn counts, appearance, and weave types. All weave patterns of tested fabric samples are successfully recognized and computed yarn counts are consistent to the manual counts.
Secondly, we present a methodology for using the high resolution 3D surface data of fabric samples to measure surface roughness in a nondestructive and accurate way. A parameter FDFFT, which is the fractal dimension estimation from 2DFFT of 3D surface scan, is proposed as the indicator of surface roughness. The robustness of FDFFT, which consists of the rotation-invariance and scale-invariance, is validated on a number of computer simulated fractal Brownian images. Secondly, in order to evaluate the usefulness of FDFFT, a novel method of calculating standard roughness parameters from 3D surface scan is introduced. According to the test results, FDFFT has been demonstrated as a fast and reliable parameter for measuring the fabric roughness from 3D surface data. We attempt a neural network model using back propagation algorithm and FDFFT for predicting the standard roughness parameters. The proposed neural network model shows good performance experimentally.
Finally, an intelligent approach for the interpretation of fabric objective measurements is proposed using supported vector machine (SVM) techniques. The human expert assessments of fabric samples are used during the training phase in order to adjust the general system into an applicable model. Since the target output of the system is clear, the uncertainty which lies in current subjective fabric evaluation does not affect the performance of proposed model. The support vector machine is one of the best solutions for handling high dimensional data classification. The complexity problem of the fabric property has been optimally dealt with. The generalization ability shown in SVM allows the user to separately implement and design the components. Sufficient cross-validations are performed and demonstrate the performance test of the system.
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Experimental characterization and modeling of the permeability of fibrous preforms using gas for direct processes application.Hou, Yi 25 October 2012 (has links) (PDF)
A methodology to measure in-plane permeability of fibrous media using a transient one dimensional air flow is developed. The method, based on the measurement of gas pressure at the boundaries throughout the transient flow, is convenient, clean and fast, avoids usage of a gas flow meter and offers a way to study the gas transport within fibrous media. The gas transport through fibrous porous media is described by several models to comply with different flow regimes. The permeability, only depending on the fibrous structure, is determined by inverse method, fitting the simulation results to the experimental data obtained using rising or dropping pressure methods. The results of viscous permeability Kv of Glass/Carbon Twill Woven fabrics (viscous permeability Kv ranging from 10-11 to 10-10 m2) measured using gas match well the permeability measured with liquid compression and injection techniques from previous works. The deviation from Darcy's law caused by gas sliding effect on low permeability Carbon Uni-Directional fabrics (Kv from 10-14 to 10-12 m2) is analyzed and a related parameter of fabric material shows a dependence in permeability, with a similar trend as the Klinkenberg sliding parameter in soils and rocks.The experimental errors due to dimensions, thermal effect, pressure variation, sample handling, and trapped gas at boundaries are analyzed. It comes out that the sensitivities of pressure sensors and trapped gas volumes at the boundaries have the most important effects. A design for 2D measurement using gas to obtain 2D permeability tensor in one single test is proposed to avoid the issues of trapped gas at boundaries. Simulated experiments show that the measurements based on pressure measured at three proposed locations could provide robust and accurate results for fabrics of anisotropic permeability ratios (K1/K2) ranging from 0.1 to 10, with various principal permeability direction orientations.
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An analysis of Late Woodland ceramics from Peter Pond Lake, SaskatchewanYoung, Patrick S. 20 February 2008 (has links)
Recent archaeological surveys on Peter Pond Lake have provided an opportunity to better elucidate the Late Woodland period of occupation in the upper Churchill River basin of northwestern Saskatchewan. Previous studies identified two pottery-bearing cultures in the region. This included the Kisis complex of the well-documented Selkirk composite, which is characterized by Winnipeg Fabric-impressed ware and dates from approximately A.D. 1300 through to the historic period. The second was a lesser-known archaeological entity represented by limited pottery recoveries from just two sites in the region. Early interpretations proposed this latter Narrows pottery represented an incursion of the plains adapted Old Womens phase into the region, with a suggested age of approximately A.D. 1000 to 1300.
<p>
Through a comprehensive analysis of pottery assemblages recently recovered from over twenty sites in the Peter Pond Lake region, this study was able to further validate the original description of the Kisis complex, but more significantly, propose a new pottery ware and complex for the enigmatic Narrows pottery assemblages. As a result, this pottery is now formally classified as Narrows Fabric-impressed ware and is considered characteristic of the Buffalo Lake complex. This complex is centered on Peter Pond Lake and appears to have an extensive presence in the region. Recently obtained radiocarbon dates indicate it is slightly younger than originally believed, and spanned from approximately A.D 1200 to 1500. Unlike previous interpretations, which suggest this pottery represents a plains influence in the region, the Buffalo Lake complex is considered a boreal forest manifestation, with origins that lie in the woodlands to the southeast. The pottery shares particular affinities with contemporaneous Sandy Lake ware that has a distribution extending from east-central Saskatchewan through to northwestern Ontario and Minnesota, with additional influences evident from Winnipeg Fabric-impressed ware found throughout northern Saskatchewan, Manitoba and Ontario.
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An analysis of Late Woodland ceramics from Peter Pond Lake, SaskatchewanYoung, Patrick S. 25 September 2009 (has links)
Recent archaeological surveys on Peter Pond Lake have provided an opportunity to better elucidate the Late Woodland period of occupation in the upper Churchill River basin of northwestern Saskatchewan. Previous studies identified two pottery-bearing cultures in the region. This included the Kisis complex of the well-documented Selkirk composite, which is characterized by Winnipeg Fabric-impressed ware and dates from approximately A.D. 1300 through to the historic period. The second was a lesser-known archaeological entity represented by limited pottery recoveries from just two sites in the region. Early interpretations proposed this latter "Narrows" pottery represented an incursion of the plains adapted Old Women's phase into the region, with a suggested age of approximately A.D. 1000 to 1300. <p>
Through a comprehensive analysis of pottery assemblages recently recovered from over twenty sites in the Peter Pond Lake region, this study was able to further validate the original description of the Kisis complex, but more significantly, propose a new pottery ware and complex for the enigmatic Narrows pottery assemblages. As a result, this pottery is now formally classified as Narrows Fabric-impressed ware and is considered characteristic of the Buffalo Lake complex. This complex is centered on Peter Pond Lake and appears to have an extensive presence in the region. Recently obtained radiocarbon dates indicate it is slightly younger than originally believed, and spanned from approximately A.D 1200 to 1500. Unlike previous interpretations, which suggest this pottery represents a plains influence in the region, the Buffalo Lake complex is considered a boreal forest manifestation, with origins that lie in the woodlands to the southeast. The pottery shares particular affinities with contemporaneous Sandy Lake ware that has a distribution extending from east-central Saskatchewan through to northwestern Ontario and Minnesota, with additional influences evident from Winnipeg Fabric-impressed ware found throughout northern Saskatchewan, Manitoba and Ontario.
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Zero-Valent Iron Decolorization of the Anthraquinone Dye Reactive Blue 4 and Biodegradation Assessment of its Decolorization ProductsYang, Hanbae 18 April 2005 (has links)
Anthraquinone dyes constitute the second largest class of textile dyes, and are used extensively in the textile industry. A high fraction of the initial reactive dye mass used in the dyeing process remains in the spent dyebath. Reactive dyes are not readily removed by typical wastewater treatment processes and the high salt concentration typical of reactive dyeing further complicates the management of spent reactive dyebaths. Investigation of the reductive transformation of reactive anthraquinone dyes and their decolorization products has been very limited. Additionally, very limited research has been conducted on the decolorization of spent reactive dyebaths.
Research was conducted to investigate the key operational parameters of batch and continuous-flow ZVI decolorization of a reactive anthraquinone dye, Reactive Blue 4 (RB4), under anoxic conditions, as well as the potential for the biodegradation of its decolorization products in a halophilic culture under aerobic conditions. The effect of two operational parameters, such as mixing intensity and initial dye concentration, on the ZVI batch decolorization kinetics indicates that ZVI decolorization of RB4 is a surface-catalyzed, mass transfer-limited process. The high salt and base concentrations enhanced the rate of RB4 decolorization. Based on parameters such as porosity, hydraulic conductivity, pore water velocity, and dispersion coefficient, non-ideal transport characteristics were observed in a continuous-flow ZVI column. The results of a long-term continuous-flow ZVI decolorization kinetics demonstrated that continuous-flow ZVI decolorization is feasible. However, column porosity losses and a shift of reaction kinetics occur in long-term column operation. ZVI decolorization of RB4 was successfully described with a pseudo first-order or a site saturation model. Lastly, the RB4 decolorization products generated by ZVI treatment had no inhibitory effect on the halophilic culture. However, biodegradation and/or mineralization of RB4 decolorization products was not observed after a long-term incubation of the culture.
This research demonstrated the feasibility of ZVI decolorization of reactive anthraquinone dyes, which will help in the development of a continuous-flow, dyebath decolorization process and the possible reuse of the renovated dyebath in the dyeing operation. Such a system could lead to substantial reduction of water usage, as well as a decrease of salt and dye discharges.
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Structural Design, Analysis And Composite Manufacturing Applications For A Tactical Unmanned Air VehicleSoysal, Sercan 01 May 2008 (has links) (PDF)
In this study structural design, analysis and composite manufacturing applications for a tactical UAV, which was designed and manufactured in Aerospace Engineering Department of Middle East Technical University (METU), is introduced. In order to make an accurate structural analysis, the material and loading is modeled properly. Computational fluid dynamics (CFD) was used to determine the 3D pressure distribution around the wing and then the nodal forces were exported into the finite element program by means of interpolation from CFD mesh to finite element mesh. Composite materials which are mainly used in METU TUAV are woven fabrics which are wetted with epoxy resin during manufacturing. In order to find the elastic constants of the woven fabric composites, a FORTRAN code is written which utilizes point-wise lamination theory. After the aerodynamic load calculation and material characterization steps, linear static and dynamic analysis of the METU TUAV&rsquo / s wing is performed and approximate torsional divergence speed is calculated based on a simplified approach. Lastly, co-cured composite manufacturing of a multi-cell box structure is explained and a co-cured multi-cell box beam is manufactured.
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Cement Penetrability Characteristics in Textile Cement SystemsPeled, Alva 03 June 2009 (has links) (PDF)
Cement penetrability is a key factor in multifilament cement composites. However, the modes of action and the concepts vary because of brittle and ductile fibers. In the case of brittle fibers such as glass, high penetrability of cement products in between the bundle filaments can lead to brittle composite behavior, and therefore addition in ductility is required. In order to have efficient bundle action and high bonding, fillers can be introduced in between the glass filaments, keeping the telescopic mode of failure but at the same time improving the bond and stress transfer within the filaments of the bundle, even at late ages, resulting in a ductile and high strength composite. On the other hand, ductile fibers such as polypropylene (PP), which also developing low bonding with the cement matrix, result in ductile cement composite but with relatively low strength. Therefore, in this case good penetrability of the cement in between the filaments of the bundle is essential in order to maximize the reinforcing efficiency of the bundle by improving bond. The penetrability of the matrix into a fabric structure and especially in between the bundle filaments made up the fabric is a result of fiber- matrix compatibility, which depends on: level of opening and spaces between the filaments, bundle surface properties including wetting and chemical affinity to the cement matrix, matrix viscosity, processing of the composite, and the nature of the fabric junctions and the resulting tightening effects of the bundle, i.e., influenced by the fabric structure itself.
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Εύρεση σχεδιαστικών αποκλίσεων αντικειμένων με υφήΠρινόπουλος, Σαράντης 25 May 2009 (has links)
Αυτή η εργασία μελετά την εφαρμογή προηγμένων τεχνικών επεξεργασίας εικόνας από υπολογιστές για την επίλυση του προβλήματος της ανίχνευσης ατελειών σε υφάσματα από τις βιομηχανίες παραγωγής υφασμάτων. Προτείνεται μία νέα μέθοδος ανίχνευσης ατελειών, η οποία αποτελείται από ένα περιττό συμμετρικό φίλτρο Gabor πραγματικών τιμών, ένα άρτιο συμμετρικό φίλτρο Gabor πραγματικών τιμών και ένα φίλτρο εξομάλυνσης. Κατά την ανάπτυξη της μεθόδου, τα φίλτρα Gabor σχεδιάζονται με βάση τα χαρακτηριστικά του texture που εξάγονται βέλτιστα από μία εικόνα ενός μη ελαττωματικού υφάσματος με τη χρήση ενός Gabor Wavelet Network (GWN). Η απόδοση της προτεινόμενης μεθόδου αξιολογείται με τη χρήση ενός σετ εικόνων υφασμάτων που προέρχονται από μία βάση δεδομένων που περιέχει μία μεγάλη ποικιλία εικόνων ομογενών υφασμάτων. Τα αποτελέσματα παρουσιάζουν ακρίβεια στην ανίχνευση ατελειών με πολύ λίγες λάθος ανιχνεύσεις, από όπου φαίνεται η αποτελεσματικότητα της προτεινόμενης μεθόδου. Τα πειραματικά αποτελέσματα επιβεβαίωσαν τις δυνατότητες της μεθόδου και ένας υπολογισμός του υπολογιστικού φορτίου που χρειάζεται για την υλοποίηση της έδειξε ότι μπορεί να χρησιμοποιηθεί ακόμα και σε συστήματα ανίχνευσης πραγματικού χρόνου. / -
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Grey Stations: New Strategies for Senior Housing in Vancouver, BCMackie, Neal 18 March 2014 (has links)
This thesis proposes a strategy to capitalize on the abundance of derelict service stations in Vancouver, BC, as a means to address the current crisis of seniors’ housing and services. Vancouver’s glut of vacant service stations reflects a widespread trend of service station closures across North America. As former service stations, these sites are commonly contaminated and have to undergo remediation before they can be rezoned for other uses. However, this network of sites has great potential for long term development. The goal is to create an alternative to the homogeneous seniors’ home currently available and establish a network of ‘Community Stations’ spread throughout the city. These sites will act as nodes to provide housing and services for seniors in the local community. The design is a phased development which will allow time for the site to remediate as well as, through community involvement, establish value and ownership.
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Analyse et simulation de la mise en forme des renforts de composites NCFBel, Sylvain 22 November 2011 (has links) (PDF)
Grâce à leur géométrie spécifique, faite d'une superposition de couches unidirectionnelles de fibres continues, liées par des coutures plus ou moins complexes, les renforts NCF (Non-Crimp Fabric) possèdent une combinaison de propriétés intéressantes. Ces propriétés permettent l'utilisation de procédés de production tels que le procédé RTM (Resin Transfer Moulding) et permettent l'utilisation des caractéristiques de rigidité élevée des fibres dans la pièce finale. Ainsi, ces renforts trouvent des applications dans différents secteurs de l'industrie des composites et notamment en aéronautique. Les couches, formées de fibres parallèles juxtaposées, sont liées par différents types de coutures. Ce lien conduit à des propriétés différentes de celles observées sur un renfort tissé où les mèches de chaîne et de trame sont liées par entrelacement. Par conséquent, la cinématique de déformation des renforts NCF secs lors de la mise en forme peut être différente. Dans ce travail de recherche, nous menons d'abord une étude expérimentale sur les mécanismes de déformation se produisant lors de tests élémentaires et lors d'une expérience d'emboutissage. Plusieurs renforts NCF et un renfort interlock sont étudiés. Ensuite, nous introduisons un nouveau modèle pour la simulation de la mise en forme du renfort de composite NCF sec. Cette approche implique l'utilisation d'éléments finis lagrangien semi-discrets pour représenter les couches et d'éléments de barres pour représenter les coutures. Ce modèle nécessite un algorithme de contact spécifique pour gérer la relation entre les éléments finis. Une loi de frottement de Coulomb avec seuil de glissement est utilisée. Enfin, le modèle est validé par l'intermédiaire de l'essai de bias test puis la mise en forme sur un hémisphère est simulée et comparée à l'expérience.
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