Technology 2000, volume 1

The purpose of the conference was to increase awareness of existing NASA developed technologies that are available for immediate use in the development of new products and processes, and to lay the groundwork for the effective utilization of emerging technologies. There were sessions on the following: Computer technology and software engineering; Human factors engineering and life sciences; Information and data management; Material sciences; Manufacturing and fabrication technology; Power, energy, and control systems; Robotics; Sensors and measurement technology; Artificial intelligence; Environmental technology; Optics and communications; and Superconductivity

Imaging Fines Migration Induced by Salinity Changes

This project aims at confirming positive LS-EOR (low salinity enhanced oil recovery) effects with fluorescent microscopy, an unprecedented approach. The fluorescent microscopy employed in this project used a confocal microscope and total internal reflection fluorescence (TIRF); these allowed the acquisition of 3D images using a non-destructive procedure. For the first part of the project, confocal microscopy was utilised to test the average fluorescent intensity and the scope of 8 different types of clay minerals. Comparing fluorescent features of high and low defect kaolinite, also 3 types of LDH Mg/Al and another 3 types of LDH Mg/Fe were included in this study. Moreover, SEM was applied to analyse the structure of clay minerals, and XRD was applied to determine the impurities within the clay samples. The sample which determined that clay minerals fluoresce on a consistent basis were aged with formation brine and either polar crude oil or non-polar crude oil, these aged clay samples were utilised for the second part of the project, which was aimed at observing any movement of clay by lowering the salinity. AFM and TIRF were employed for the latter section. Based upon the attained results, the following is notable: firstly, that the presence of iron in clay minerals diminishes the fluorescent intensity, also high defect clay minerals do not exhibit a steady fluorescence intensity. Secondly, testing with SEM and XRD revealed that KGa-1b might be the only clay sample that has the potential of autofluorescence, since the percentage of fluoresced pixels was more than the percentage of impure minerals that would fluoresce at the applied wavelength. Finally, AFM and TIRF confirmed LS-EOR effects even without the presence of polar components in the system, especially after fourfold dilution from the initial ionic concentration caused the clay minerals to move more vigorously; significant clay swelling at the salinity level was also witnessed. In summary, the novel approach of TIRF is deemed well suited in terms of its technique for the study of fines migration. Four-fold dilution of high salinity brine initiated clay swelling and dispersion, still salinity higher than generally accepted as the LS-EOR optimal salinity level was given. It can be interpreted that fines dispersion and migration could be initiated at a higher salinity, while the emulsion phase form and the oil molecule surface release may require a much lower ionic concentration in order to enable residual oil recovery. LS-EOR effects observed under the TIRF and AFM, arising due to the weaker electrostatic forces developed by lowering the system's salinity hence, the generally accepted importance of polar oil components for LS-EOR effects does not hold in these experiments. Positive LS- EOR effects revealed by TIRF, AFM, and FFM consequently concluded that electrical double layer expansion would be the most dominant attribution for LS-EOR

The Second Joint NASA/FAA/DOD Conference on Aging Aircraft

The purpose of the Conference was to bring together world leaders in aviation safety research, aircraft design and manufacturing, fleet operation and aviation maintenance to disseminate information on current practices and advanced technologies that will assure the continued airworthiness of the aging aircraft in the military and commercial fleets. The Conference included reviews of current industry practices, assessments of future technology requirements, and status of aviation safety research. The Conference provided an opportunity for interactions among the key personnel in the research and technology development community, the original equipment manufacturers, commercial airline operators, military fleet operators, aviation maintenance, and aircraft certification and regulatory authorities. Conference participation was unrestricted and open to the international aviation community

Transparent, Lightweight, High Performance Polymer Films and Their Composites.

PhD ThesisThis thesis aims to develop novel polymeric material with an excellent balance in high optical transparency and mechanical properties. More particularly, the current thesis reports the processing and characterization of highly oriented transparent polyethylene films and their use in laminated composites. First, highly transparent high-density polyethylene (HDPE) films with high modulus and tensile strength were developed by regulating solid-state drawing conditions without the need of additives. The effects of drawing parameters like drawing temperature and draw ratio on optical and mechanical properties as well as morphology of these solid-state drawn HDPE films were methodically investigated. It was found that a fairly broad processing window can be utilized to tailor the required balance in optical and mechanical performance. Subsequently, the production of these ultra-drawn transparent HDPE films was carried out using a scalable and continuous cast-film extrusion and drawing process. High optical transparency of around 91 % was achieved even in the far field. A maximum modulus of ~ 33 GPa and tensile strength of ~ 900 MPa of these solid-state drawn HDPE films was attained without compromising optical transparency, which is an order of magnitude higher than mechanical properties of conventional transparent plastics such as polycarbonate (PC) and poly(methyl methacrylate) (PMMA). The influence of extrusion draw down and two-step drawing on optical and mechanical behaviours was also explored. Finally, these highly oriented transparent HDPE films were used as the reinforcing phase in high performance transparent composite laminates. The far field light transmittance of Abstract 6 4-layer HDPE-reinforced laminates with either a unidirectional (UD) or bidirectional (BD) lay-up sandwiched between glass or PC skins, was maintained at around 85 %. The fabricated transparent composite laminates were shown to have not only a high tensile strength but also a high energy absorption capability, outperforming existing transparent glazing materials such as laminated glass or PC

Plant-Based Structures as an Opportunity to Engineer Optical Functions in Next-Generation Light Management

This review addresses the reconstruction of structural plant components (cellulose, lignin, and hemicelluloses) into materials displaying advanced optical properties. The strategies to isolate the main building blocks are discussed, and the effects of fibrillation, fibril alignment, densification, self-assembly, surface-patterning, and compositing are presented considering their role in engineering optical performance. Then, key elements that enable lignocellulosic to be translated into materials that present optical functionality, such as transparency, haze, reflectance, UV-blocking, luminescence, and structural colors, are described. Mapping the optical landscape that is accessible from lignocellulosics is shown as an essential step toward their utilization in smart devices. Advanced materials built from sustainable resources, including those obtained from industrial or agricultural side streams, demonstrate enormous promise in optoelectronics due to their potentially lower cost, while meeting or even exceeding current demands in performance. The requirements are summarized for the production and application of plant-based optically functional materials in different smart material applications and the review is concluded with a perspective about this active field of knowledge

Automated visual inspection for the quality control of pad printing

Pad printing is used to decorate consumer goods largely because of its unique ability to apply graphics to doubly curved surfaces. The Intelpadrint project was conceived to develop a better understanding of the process and new printing pads, inks and printers. The thesis deals primarily with the research of a printer control system including machine vision. At present printing is manually controlled. Operator knowledge was gathered for use by an expert system to control the process. A novel local corner- matching algorithm was conceived to effect image segmentation, and neuro-fuzzy techniques were used to recognise patterns in printing errors. Non-linear Finite Element Analysis of the rubber printing-pad led to a method for pre-distorting artwork so that it would print undistorted on a curved product. A flexible, more automated printer was developed that achieves a higher printing rate. Ultraviolet-cured inks with improved printability were developed. The image normalisation/ error-signalling stage in inspection was proven in isolation, as was the pattern recognition system

A novel transparent and flexible pressure sensor for the human machine interface

The movement towards flexible and transparent electronics for use in displays, electronic skins, musical instruments and automotive industries, demands electrical components such as pressure sensors to evolve alongside circuitry and electrodes to ensure a fully flexible and transparent system. In the past, piezoresistive pressure sensors made with flexible electrodes have been fabricated, however, many of these systems are opaque. For the first time, we present a technology that exploits the natural self-assembly of polystyrene nanospheres to reproducibly create nanostructured materials to be used in optically transparent pressure sensors with sensing performance comparable to opaque industry standards. The performance of the piezoresistive pressure sensor relies on uniform elastic nano-dome arrays. A thin and homogeneous lining of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) renders the domes conductive and retains the transparent and flexible qualities of the underlying polymer. The film transparency is primarily dependant on PEDOT:PSS film thickness where transparencies as high as 79.3 \% are achieved for films of less than 100 nm in thickness. The sensors demonstrate a resistance response across the force range appropriate for all human machine interface interactions, which correspond here to 0.07 to 26 N. The fabrication process involves the creation of an electroactive mould which is used to create nanostructred polymer layers. To enable mould reuse and enhance process efficiency, an anti-adhesive treatment in the form of a self-assembled monolayer of alkanethiols has been developed. Three chain lengths for the alkanethiol of chemical structure H$_{3}$C-(CH$_{2}$)$_{n}$-SH where n = 3, 5, and 11 are investigated and SAM functionalisation is confirmed with XPS. Peel tests prove that all three are effective at preventing adhesion between the mould and PEDOT:PSS and the treatment is shown not to be detrimental to the polymer electrodeposition process. An adapted fabrication procedure with custom designed electrode housing enables larger samples to be created for prototype devices. A simple functional prototype in the form of a multi-pixel force sensor atop of an LED display is successfully designed and fabricated to highlight the technology for use at the human machine interface.Open Acces

Schalten funktionalisierter, photochromer Oberflächen mittels Organischer Leuchtdioden

This work describes the development of photo-switchable surfaces based on the two most common photochromic molecules. Additionally, these surfaces are excited with thin organic LEDs (OLEDs). With this combination an intelligent and programmable surface is realizable. Here, a flexible PDMS copy of a lotus leaf covered with a single molecule layer of azobenzenes enables a 200 times higher relative transparency switching for a 355 nm laser beam compared to a flat glass substrate. Thereby a simple spatially resolved mapping of the azobenzene state on the surface becomes possible. A reversible contact angle switching between 138° and 95° is achieved with a non-covalently bound spiropyran layer on a candle soot surface. Then, a blue OLED is designed and fabricated that possesses a radiant flux of up to over 10 mW/cm2. It is used to switch both photochromic surfaces. With the aim to increase the switching speed, the light outcoupling from OLEDs is enhanced. Tetrapodal zinc oxide particles are used to couple out trapped substrate modes. In order to use many OLEDs efficiently next to each other for the switching of a photochromic layer, it is necessary to direct the light of their usually more Lambertian emitting profile. For this, optical gratings are integrated into OLEDs. Here, it is shown how the change of emitter position, refractive index contrast and absorption increase the resonances of these gratings. In addition, grating effects on a fully flexible PDMS substrate are investigated and the first goniometric electroluminescene measurement of an OLED with an integrated multi-periodic grating is presented.Diese Arbeit beschreibt die Entwicklung von photoschaltbaren Beschichtungen auf Basis der beiden gängigsten photochromen Moleküle. Zusätzlich werden diese Schichten mit organischen LEDs (OLEDs) angeregt. Durch diesen Integrationsschritt lässt sich eine „intelligente“ und programmierbare Oberfläche erzeugen. Eine mit einer einfachen Azobenzol-Molekül-Schicht versehene Kopie eines Lotusblattes aus flexiblem PDMS erlaubt hier ein um den Faktor 200 verstärktes Schalten der relativen Transmission eines Laserstrahles mit 355 nm Wellenlänge gegenüber einem glatten Glassubstrat, welches ebenfalls funktionalisiert wurde. Dadurch wird eine einfache Kartierung der Azobenzolzustände auf der Oberfläche möglich. Eine reversible Kontaktwinkelschaltung zwischen 138° und 95° wird mit nicht-kovalent aufgebrachten Spiropyranen auf Kerzenrußoberflächen erzielt. Im Anschluss wird eine blaue OLED designt und hergestellt, die eine Strahlungsleistung von bis zu über 10 mW/cm2 aufweist. Beide Oberflächen werden mittels dieser OLED geschaltet. Mit dem Ziel einer Steigerung der Schaltgeschwindigkeit wird versucht, die Lichtauskopplung aus OLEDs zu erhöhen. Für die Auskopplung gefangener Substratmoden werden tetrapodale Zinkoxidpartikel verwendet. Um später möglichst viele OLEDs unter einer photochromen Schicht nebeneinander betreiben zu können, ist es zudem notwendig, deren eher Lambertsches Abstrahlprofil zu richten. Dafür eignen sich in OLEDs eingebrachte optische Gitter. Hier wird mittels verschiedener Experimente dargelegt, wie sich die Resonanzen der Gitter durch Veränderung von Emitterposition, Brechungsindexkontrast und Absorption verstärken lassen. Des Weiteren wird der Gittereffekt in OLEDs auf flexiblen PDMS untersucht und zum ersten Mal eine goniometrische Elektrolumineszenzmessung einer OLED mit einem integrierten multiperiodischen Gitter gezeigt

Current Air Quality Issues

Air pollution is thus far one of the key environmental issues in urban areas. Comprehensive air quality plans are required to manage air pollution for a particular area. Consequently, air should be continuously sampled, monitored, and modeled to examine different action plans. Reviews and research papers describe air pollution in five main contexts: Monitoring, Modeling, Risk Assessment, Health, and Indoor Air Pollution. The book is recommended to experts interested in health and air pollution issues

Enhancement of thermal, electrical and optical properties of zinc oxide filled polymer matrix nano composites

Thesis (Doctoral)--Izmir Institute of Technology, Chemical Engineering, Izmir, 2009Includes bibliographical references (leaves: 169-181)Text in English; Abstract: Turkish and Englishxvii, 191 leavesThe purpose of this study is to enhance the electrical, thermal and optical properties of polyethylene and polypropylene by the addition of zinc oxide (ZnO) filler.Embedding ZnO in a polymeric matrix could make an economic, weight saving, chemically resistive, optical, flexible and conductive materials which possesses the properties of zinc oxide.Composites with higher electrical and thermal conductivity having luminescence properties were prepared using commercial and hydrothermally synthesized ZnO powders with different particle size and conductivity. Effect of ZnO loading and surface treatment on composite properties was investigated. Luminescence effects in green and blue regions were detected in all powders due to the defects on the structure of ZnO.The powders were found to be moderately conductive materials, as well. Un-homogenously dispersed composites were prepared using rheomixer since especially nano powders tended to be agglomerated in the composite. On the other hand, different surface properties of powder and polymer caused adhesion and wetting problems. Microvoids were detected in the interphase, as well.Composites can be used as an electrostatic dissipation and moderate electrical conductive applications in the field of electrical conductivity, as a heat sink in the field of thermal conductivity and as a solid state lamp due to luminescence properties. Stiffness of the composites was very high compared to neat polymer and can be properly used as an engineering material