A Public Fabric Database for Defect Detection Methods and Results

[EN] The use of image processing for the detection and classification of defects has been a reality for some time in science and industry. New methods are continually being presented to improve every aspect of this process. However, these new approaches are applied to a small, private collection of images, which makes a real comparative study of these methods very difficult. The objective of this paper was to compile a public annotated benchmark, that is, an extensive set of images with and without defects, and make these public, to enable the direct comparison of detection and classification methods. Moreover, different methods are reviewed and one of these is applied to the set of images; the results of which are also presented in this paper.The authors thank for the financial support provided by IVACE (Institut Valencia de Competitivitat Empresarial, Spain) and FEDER (Fondo Europeo de Desarrollo Regional, Europe), throughout the projects: AUTOVIMOTION and INTELITEX.Silvestre-Blanes, J.; Albero Albero, T.; Miralles, I.; Pérez-Llorens, R.; Moreno, J. (2019). A Public Fabric Database for Defect Detection Methods and Results. AUTEX Research Journal. 19(4):363-374. https://doi.org/10.2478/aut-2019-0035S36337419

Image Classification of High Variant Objects in Fast Industrial Applications

Recent advances in machine learning and image processing have expanded the applications of computer vision in many industries. In industrial applications, image classification is a crucial task since high variant objects present difficult problems because of their variety and constant change in attributes. Computer vision algorithms can function effectively in complex environments, working alongside human operators to enhance efficiency and data accuracy. However, there are still many industries facing difficulties with automation that have not yet been properly solved and put into practice. They have the need for more accurate, convenient, and faster methods. These solutions drove my interest in combining multiple learning strategies as well as sensors and image formats to enable the use of computer vision for these applications. The motivation for this work is to answer a number of research questions that aim to mitigate current problems in hinder their practical application. This work therefore aims to present solutions that contribute to enabling these solutions. I demonstrate why standard methods cannot simply be applied to an existing problem. Each method must be customized to the specific application scenario in order to obtain a working solution. One example is face recognition where the classification performance is crucial for the system’s ability to correctly identify individuals. Additional features would allow higher accuracy, robustness, safety, and make presentation attacks more difficult. The detection of attempted attacks is critical for the acceptance of such systems and significantly impacts the applicability of biometrics. Another application is tailgating detection at automated entrance gates. Especially in high security environments it is important to prevent that authorized persons can take an unauthorized person into the secured area. There is a plethora of technology that seem potentially suitable but there are several practical factors to consider that increase or decrease applicability depending which method is used. The third application covered in this thesis is the classification of textiles when they are not spread out. Finding certain properties on them is complex, as these properties might be inside a fold, or differ in appearance because of shadows and position. The first part of this work provides in-depth analysis of the three individual applications, including background information that is needed to understand the research topic and its proposed solutions. It includes the state of the art in the area for all researched applications. In the second part of this work, methods are presented to facilitate or enable the industrial applicability of the presented applications. New image databases are initially presented for all three application areas. In the case of biometrics, three methods that identify and improve specific performance parameters are shown. It will be shown how melanin face pigmentation (MFP) features can be extracted and used for classification in face recognition and PAD applications. In the entrance control application, the focus is on the sensor information with six methods being presented in detail. This includes the use of thermal images to detect humans based on their body heat, depth images in form of RGB-D images and 2D image series, as well as data of a floor mounted sensor-grid. For textile defect detection several methods and a novel classification procedure, in free-fall is presented. In summary, this work examines computer vision applications for their practical industrial applicability and presents solutions to mitigate the identified problems. In contrast to previous work, the proposed approaches are (a) effective in improving classification performance (b) fast in execution and (c) easily integrated into existing processes and equipment

Elektrické zvlákňování: koncept výroby nanovláken a mikrovláken, možné aplikace vlákenných materiálů

Habilitační práce je předložena ve formě komentovaného souboru prací dle Zákona č. 111/1998 Sb. Publikované výsledky přibližují význačný svět nanovláken a mikrovláken, zároveň také samotné technologie vedoucí k jejich přípravě. Habilitační práce je sepsána jako komentovaný soubor sebraných vědeckých prací. Jedná se o soubor impaktovaných článků, které jsou zaznamenány v databázích WoS nebo Scopus. Všechny publikované články jsou podpořeny uveřejněnými patenty, užitnými vzory, nebo přijatými patentovými přihláškami. Propojení všech těchto vědeckých a inženýrských prací může být důkazem, že aplikace nanovlákenných i mikrovlákenných materiálů směřují do průmyslové praxe. Dle zákona č. 111/1998 Sb je nutné uvádět také výstupy vědecko-pedagogické činnosti. Kvantifikace výsledků VaV bude uvedena v přehledné souhrnné tabulce v kapitole soubor vědeckých prací. Habilitační práce je orientována na textilní technologie výroby vlákenných i nanovlákenných materiálů vhodných pro zdravotnické i technické aplikace. V práci jsou uveřejněny výsledky technického i biologického zaměření. Originalita práce spočívá zejména v propojení vědeckých publikací přímo s uveřejněnými patenty nebo užitnými vzory. V současné době je cíleno na možnou komercionalizaci vědeckých výstupů ve formě spolupráce s výrobním subjektem. V práci je uvedena přímá návaznost vědeckých článků a jejich propojení s průmyslovou sférou. Přínosem podaných výsledků je zejména novost vytvořených nanovlákenných materiálů a jejich následný aplikační potenciál. Příkladem může být nanovlákenný kožní kryt pro léčbu kožních poranění, který je ve fázi klinického testování. Pedagogická činnost zahrnuje výuku dvou předmětů, Zdravotnické textilie a předmětu Termické a chemické technologie.The habilitation thesis is presented in the form of a commented work file according to Act No. 111/1998 Coll. The published results illustrate the prominent world of nanofibers and microfibers as well as the technology itself leading to their preparation. Habilitation thesis is written as a commented collection of collected scientific papers. These are impacted articles that are recorded in WoS or Scopus databases. All published articles are supported by published patents, utility models, or accepted patent applications. The continuity of all these scientific and engineering work may be evidence that the application of nanofibrous and microfibre materials leads to industrial practice. According to the law, it is also necessary to include scientific and pedagogical activities. Quantification of the R & D results will be presented in a synoptical summary table in the chapter of scientific work. The habilitation thesis is oriented on the textile technology of production of fiber and nanofibrous materials suitable for medical and technical applications. In the work are published the results of the technical and biological focus. The originality of the work is mainly the linking of scientific publications directly with published patents or utility models. At present, there is a pressure on the possible commercialization of scientific outputs in the form of cooperation with the manufacturing entity. There is a direct link between the scientific articles and their links with the industrial sphere. The benefit of the results is the novelty of the created nanofibrous materials and their future application potential. An example can be a nanofibrous skin cover for the treatment of skin injuries that is in the clinical trial phase. Pedagogical activity is supported by the teaching of two subjects: Medical Textiles and Thermal and Chemical Technologies

Side-emitting fibers: targeted light scattering in optical fibers

Light scattering in optical fibers can transform the fiber into a linear light source with customizable emission properties: a side-emitting fiber. Side-emitting fibers are light sources with special angular and longitudinal emission characteristics, not generally encountered in other light sources: they emit radiation in all directions like a diffuse light source, but the emission is preferentially directed forward. Also, the fiber’s surface emission may decrease exponentially or vary along the fiber. The contribution of this dissertation to the literature on side-emitting fibers is twofold; first, it will show how these fiber emission parameters will influence the generated light field in the proximity and the far field. Second, it will show how to customize the emission properties by using femtosecond laser-generated scattering centers: Arranging these building blocks can generate customized longitudinal emission profiles. Furthermore, it will derive an electromagnetic model of the scattering behavior of these modifications to show how their stochastic properties, shape, and volume affect the angular emission profile and their scattering power

Photocatalytic applications of layered niobates and their composites

Photocatalytic applications of two-dimensional (2D) materials have called great interest due to several electronic and structural advantages. Among these materials, layered niobates are well-known photocatalysts for H2 evolution with a rich surface chemistry. Taking into account the highly exposed active sites of its 2D structure and the morphological flexibility, the properties of the exfoliated hexaniobate as a heterogeneous photocatalyst has been explored in this work, with particular attention to the electronic and interfacial processes involved in the H2 evolution. Firstly, highly efficient photocatalytic surfaces were obtained through the layer-by-layer (LbL) deposition of hexaniobate nanoscrolls on conductive glasses. These films were deposited by using poly(allylamine hydrochloride) as a polyelectrolyte and further thermal treatment leading to films composed of a fuzzy assembly of hexaniobate nanoscrolls. This configuration favored the diffusion of water and methanol molecules thus facilitating an efficient H2 evolution. Moreover, pre-adsorption of [Pt(NH3)4]2+ cations on the niobate layers allowed the production of metallic Pt nanoclusters within the nanoscrolls. The Pt-modified films exhibited apparent quantum yields of (4.0 ± 0.5) % for H2 evolution from water/methanol mixtures under UV-A irradiation. Then, in order to induce novel electronic processes without changing the bulk properties of the hexaniobate, surface modification was performed by grafting with metallic nanoclusters. Exfoliated hexaniobate (K4−xHxNb6O17) composites with metal ions such as Co2+, Fe3+ and Cu2+ were prepared and their photocatalytic properties were fully investigated. Morphological characterization showed that the grafting ions are attached to the hexaniobate surface forming amorphous clusters. These species induce an additional absorption feature in the UV-A region, which is attributed to an interfacial charge transfer from the niobate valence band to the metal ion centers. In the case of Co2+ and Fe3+, enhanced UV-driven photoactivity in plain water was observed for 0.1 wt.% grafted samples, especially for those modified with Co2+ ions, while smaller H2 evolution rates are observed as the concentration of the grafting ions increased. When Pt was added to the photocatalyst, the H2 evolution rate for the 0.1% Co-grafted sample in plain water was 70% higher than that observed for the nongrafted Pt-hexaniobate. For Cu2+-grafted hexaniobates, Cu2+ clusters provided an expressive improvement in the photocatalytic H2 evolution under UV-vis irradiation from methanolic aqueous solution and promising results for partial water splitting, in comparison to the hexaniobate with photodeposited Pt. These species on the hexaniobate surface present a high redox reversibility, being easily reduced to Cu1+/Cu0 and reoxidized to Cu2+. Cu2+ ions work as electron scavenger following band gap excitation while the resulting reduced species act as active sites to produce H2. Thus, the presence of different ions at different concentrations can directly affect the fate of the photogenerated carriers thus triggering the photocatalytic activity in different ways. Overall, the grafted ions contribute to a more efficient charge separation and to higher photocatalytic performances.Photokatalytische Anwendungen von zweidimensionalen (2D) Materialien haben aufgrund ihrer zahlreichen elektronischen und strukturellen Vorteile großes Interesse geweckt. Unter diesen Materialien sind Schichtniobate bekannte Photokatalysatoren für die H2-Entwicklung mit einer reichen Oberflächenchemie. Unter Berücksichtigung der stark exponierten aktiven Zentren seiner 2D-Struktur und der morphologischen Flexibilität wurden die Eigenschaften des Hexaniobatschichten als heterogener Photokatalysator in dieser Arbeit untersucht, mit besonderem Augenmerk auf die elektronischen und Grenzflächenprozesse, die an der H2-Entwicklung beteiligt sind. Zunächst wurden hocheffiziente photokatalytische Oberflächen durch die schichtweise (LbL) Abscheidung von Hexaniobat-Nanorollen auf leitfähigen Gläsern erhalten. Diese Filme wurden unter Verwendung von Poly(allylaminhydrochlorid) als Polyelektrolyt abgeschieden und eine weitere thermische Behandlung führte zu Filmen, die aus einer ungeordneten Anordnung von Hexaniobat-Nanorollen bestanden. Diese Konfiguration begünstigte die Diffusion von Wasser- und Methanolmolekülen und erleichterte eine effiziente H2-Entwicklung. Darüber hinaus ermöglichte die Voradsorption von [Pt(NH3)4]2+-Kationen auf den Niobatschichten die Produktion von metallischen Pt-Nanoclustern in den Nanorollen. Die Pt-modifizierten Filme zeigten scheinbare Quantenausbeuten von (4,0 ± 0,5) % für die H2-Entwicklung aus Wasser/Methanol-Gemischen unter UV-A-Bestrahlung. Um neuartige elektronische Prozesse zu induzieren, ohne die Volumeneigenschaften des Hexaniobats zu verändern, wurde anschließend eine Oberflächenmodifizierung durch grafting mit metallischen Nanoclustern durchgeführt. Exfoliierte Hexaniobat(K4−xHxNb6O17)-Komposite mit Metallionen wie Co2+, Fe3+ und Cu2+ wurden hergestellt und ihre photokatalytischen Eigenschaften wurden vollständig untersucht. Die morphologische Charakterisierung zeigte, dass grafting Modifizierungen an die Hexaniobatoberfläche angelagert sind und amorphe Cluster bilden. Diese Spezies induzieren eine zusätzliche Absorptionseigenschaft im UV-A-Bereich, die einem Ladungstransfer an der Grenzfläche vom Niobat-Valenzband zu den Metallionenzentren zugeschrieben wird. Im Fall von Co2+ und Fe3+ wurde bei mit 0,1 Gew.% gepfropften Proben eine verstärkte UV-getriebene Photoaktivität in reinem Wasser beobachtet, insbesondere bei den mit Co2+-Ionen modifizierten, während mit zunehmender Konzentration der grafting Ionen geringere H2-Entwicklungsraten beobachtet werden. Wenn das Pt auf der Oberfläche des Photokatalysators abgeschieden wurde, war die H2-Entwicklungsrate für die 0,1 Gew.%ige Co Probe in reinem Wasser 70% höher als die, die für das Pt-Hexaniobat vor dem grafting beobachtet wurde. Für Cu2+-Hexaniobate lieferten Cu2+-Cluster eine deutliche Verbesserung der photokatalytischen H2-Entwicklung aus methanolischer wässriger Lösung unter UV-Vis-Bestrahlung und vielversprechende Ergebnisse für die partielle Wasserspaltung im Vergleich zum Hexaniobat mit photoabgeschiedenem Pt. Diese Spezies auf der Hexaniobatoberfläche weisen eine hohe Redoxreversibilität auf, und können leicht zu Cu1+/Cu0 reduziert und zu Cu2+ reoxidiert werden. Cu2+-Ionen wirken nach der Bandlückenanregung als Elektronenfänger, und die resultierenden reduzierten Spezies wirken als aktives Zentrum um H2 zu produzieren. Somit kann das Vorhandensein verschiedener Ionen in unterschiedlichen Konzentrationen das Schicksal der photogenerierten Träger direkt beeinflussen und die photokatalytische Aktivität auf unterschiedliche Weise auslösen. Die grafting Ionen tragen zu einer effizienteren Ladungstrennung und höheren photokatalytischen Leistungen bei.Aplicações fotocatalíticas de materiais bidimensionais (2D) têm despertado grande interesse devido às diversas vantagens eletrônicas e estruturais desses materiais. Dentre eles, os niobatos lamelares são fotocatalisadores bem conhecidos para a evolução de H2 com uma rica química de superfície. Levando em consideração os sítios ativos altamente expostos de sua estrutura 2D e sua flexibilidade morfológica, as propriedades do hexaniobato esfoliado como fotocatalisador heterogêneo foram exploradas neste trabalho, com particular atenção aos processos eletrônicos e interfaciais envolvidos na evolução de H2. Primeiramente, superfícies fotocatalíticas de alta eficiência foram obtidas através da deposição camada por camada (LbL) de nanoscrolls de hexaniobato em vidros condutores. Esses filmes foram depositados usando poli(cloridrato de alilamina) como polieletrólito, e o posterior tratamento térmico resultou em filmes compostos por uma montagem difusa de nanoscrolls de hexaniobato. Esta configuração favoreceu a difusão das moléculas de água e metanol, facilitando uma evolução eficiente de H2. Além disso, a pré-adsorção de cátions [Pt(NH3)4]2+ nas camadas de niobato permitiu a produção de nanoaglomerados metálicos de Pt nos nanoscrolls. Os filmes modificados com Pt exibiram rendimentos quânticos aparentes de (4,0 ± 0,5)% para a evolução de H2 a partir de misturas de água / metanol sob irraditação UV-A. Em seguência, a fim de induzir novos processos eletrônicos sem alterar as propriedades do hexaniobato, a modificação da superfície foi realizada por grafting com nanoclusters metálicos. Compósitos de hexaniobato esfoliado (K4−xHxNb6O17) com íons metálicos como Co2+, Fe3+ e Cu2+ foram preparados e suas propriedades fotocatalíticas foram extensivamente investigadas. A caracterização morfológica mostrou que os íons adicionados por grafting estão fixados na superfície do hexaniobato formando aglomerados amorfos. Essas espécies induzem uma de absorção adicional característica na região UV-A, que é atribuída a uma transferência de carga interfacial da banda de valência do niobato para os centros de íons metálicos. No caso de Co2+ e Fe3+, a melhor fotoatividade conduzida por UV em água pura foi observada para amostras modificadas a 0,1%, especialmente para aquelas com íons Co2+, enquanto menores taxas de evolução de H2 são observadas conforme a concentração dos íons de grafting aumenta. Quando a Pt foi adicionada ao fotocatalisador, a taxa de evolução de H2 para a amostra modificada a 0,1% em água pura foi 70% maior do que a observada para o Pt-hexaniobato não modificado por grafting. Para hexaniobatos com Cu2+, os clusters de Cu2+ proporcionaram expressiva melhora na evolução fotocatalítica de H2 sob irradiação UV-vis de uma solução aquosa metanólica e resultados promissores para a quebra parcial da água, em comparação ao hexaniobato com Pt fotodepositada. Essas espécies na superfície do hexaniobato apresentam alta reversibilidade redox, que pode ser facilmente reduzida para Cu1+/Cu0 e reoxidada para Cu2+. Os íons Cu2+ funcionam como eliminadores de elétrons após a excitação do bandgap e as espécies reduzidas resultantes atuam como sítio ativo para produzir H2. Assim, a presença de diferentes íons em diferentes concentrações pode afetar diretamente o destino dos portadores fotogerados, desencadeando a atividade fotocatalítica de diferentes maneiras. Os íons adicionados por grafting contribuem para uma separação de carga mais eficiente e desempenhos fotocatalíticos mais elevados

Advances in Bioengineering

The technological approach and the high level of innovation make bioengineering extremely dynamic and this forces researchers to continuous updating. It involves the publication of the results of the latest scientific research. This book covers a wide range of aspects and issues related to advances in bioengineering research with a particular focus on innovative technologies and applications. The book consists of 13 scientific contributions divided in four sections: Materials Science; Biosensors. Electronics and Telemetry; Light Therapy; Computing and Analysis Techniques

Correlations between physical and structural properties of spider silk - Correlaties tussen fysische en structurele eigenschappen van spinnenzijde

Spinnen produceren tot zeven verschillende draden met opmerkelijke mechanische eigenschappen. Als gevolg hiervan is er de laatste jaren veel interesse ontstaan in het ontwerp van deze materialen voor de ontwikkeling van nieuwe proteïne-gebaseerde polymeren. Daarvoor is het vereist om de relaties tussen structuur en eigenschappen te verstaan. De bedoeling van dit doctoraatsonderzoek is om daartoe bij te dragen door het bestuderen van deze relaties voor twee types spinnenzijdes (eizak- en “dragline” spinnenzijde) in vergelijking met zijdes afkomstig van twee rupsen Bombyx mori (of gewone zijde) en Antheraea pernyi (Tussah of wilde zijde). Tijdens dit onderzoek werd vastgesteld dat eizakspinnenzijde een totaal ander mechanisch gedrag vertoont dan de overige zijdes, o.m. de dragline spinnenzijde. Gezien de literatuur zeer beperkt is over dit type spinnenzijde, werd gekozen om de focus dan ook op dit type zijde te leggen. Naast het rek-sterkte gedrag werd ook het visco-elastisch gedrag, meer bepaald het elastisch en kruipgedrag, bestudeerd. De secundaire structuur werd geanalyseerd aan de hand van Fourier-transformatie infraroodspectroscopie (FT-IR) en vastestof nucleaire magnetische resonantie (NMR) spectroscopie. Verder werd ook het thermisch gedrag bestudeerd aan de hand van thermogravimetrie (TGA) en thermische mechanische analyse (TMA). Uit het bekomen structuuronderzoek werd voor eizakspinnenzijde een structureel model afgeleid dat zijn fysische eigenschappen kan verklaren. De structuur van eizakspinnenzijde wordt gedomineerd door een uitgestrekte amorfe faze met verbonden “-turn” structuren. De kristallijne faze is beperkt en bestaat uit korte “-sheet” structuren. Beide fazen zijn verder gegroepeerd tot een niet-fibrillaire kern-mantel structuur

Engine structures: A bibliography of Lewis Research Center's research for 1980-1987

This compilation of abstracts describes and indexes the technical reporting that resulted from the scientific and engineering work performed and managed by the Structures Division of the NASA Lewis Research Center from 1980 through 1987. All the publications were announced in the l980 to 1987 issues of STAR (Scientific and Technical Aerospace Reports) and or IAA (International Aerospace Abstracts). Included are research reports, journal articles, conference presentations, patents and patent applications, and theses