NASA Tech Briefs, January 2001

The topics include: 1) A "Model" of Interactive Engineering; 2) Feature Section: Communications Technology; 3) lnReview; 4) Application Briefs; 5) Submillimeter-Wave Image Sensor; 6) Ultrasonic/Sonic Drill/Corers With Integrated Sensors; 7) Normally Closed, Piezoelectrically Actuated Microvalve; 8) Magnetostrictively Actuated Valves for Cryosurgical Probes; 9) Remote Sensing of Electric Fields in Clouds; 10) Wireless-Communication Headset Subsystem To Enhance Signaling; 11) Power Amplifier With 9 to 13 dB of Gain From 65 to 146 GHz; 12) Humidity Interlock for Protecting a Cooled Laser Crystal; 13) A Lightweight Ambulatory Physiological Monitoring System; 14) Improvements in a Lightning-Measuring Instrument; 15) Broad-Band, Noninvasive Radio-Frequency Current Probe; 16) Web-Based Technology Distributes Lean Models; 17) Software Guides Aeroelastic-Systems Design; and 18) Postprocessing Software for Micromechanics Analysis Code. A Photonics West 2001 Preview Tech Brief supplement to this January 2001 issue is also included

Contribution to the development of new photonic systems for fiber optic sensing applications

En este trabajo de doctorado se presentan nuevos sistemas y subsistemas de sensores de fibra óptica. Así, se proponen y desarrollan nuevas técnicas, componentes y tecnologías basadas en láseres de fibra con espejos distribuidos (random), fibras de cristal fotónico, estructuras de luz lenta, multiplexores de inserción y extracción (add and drop), conmutadores tele-alimentados por luz, reflectometría óptica tanto en el dominio del tiempo como de la frecuencia o filtros ópticos reconfigurables. También se han demostrado nuevas aplicaciones para estructuras de sensores tradicionales y técnicas de medida ya conocidas. Todas ellas dirigidas a la mejora del funcionamiento de los actuales transductores, redes de sensores y aplicaciones de monitorización de salud estructural. De este modo, y en primer lugar, se han desarrollado nuevos transductores puntuales. En concreto, dos sensores interferométricos basados en fibras de cristal fotónico y otro basado en una estructura resonante en anillo. También se han realizado diferentes redes de sensores utilizando OTDRs comerciales. Por un lado, se han multiplexado diferentes sensores utilizando una red en forma de bus y, por el otro, se ha interrogado de manera remota un sensor FLM/LPG a una distancia de 253 km sin necesidad de amplificación. Se han estudiado láseres basados en efecto de realimentación distribuida random (RDFB) para su uso en interrogación de sensores. Para ello, se han demostrado dos nuevos láseres multi-longitud de onda y también, por primera vez, se ha modulado un laser random. Después, se han demostrado experimentalmente varias redes de sensores de fibra óptica teniendo en cuenta los principales desafíos que estas presentan: multiplexar varios sensores en una misma red y permitir su monitorización de manera remota. En primer lugar, se han multiplexado sensores basados en la modulación de la intensidad óptica utilizando técnicas de multiplexación en dominio del tiempo. En segundo lugar, se han multiplexado sensores basados en fibras de cristal fotónico. En tercer lugar, se presentan tres nuevos métodos para la medida remota de sensores. Por último, se incluye la demostración de un conmutador de fibra óptica tele-alimentado a través de luz. Éste se utiliza en tres redes diferentes para añadir robustez e incrementar la versatilidad en la multiplexación. Finalmente, se han realizado tres pruebas de campo para aplicaciones de monitorización de salud estructural.In this PhD work, different new photonic systems and subsystems for fiber optic sensing are presented. The aim of this thesis has been to contribute to the fiber optic sensors field using modern techniques, components and technologies such as random fiber lasers, photonic crystal fibers, slow light structures, add and drop multiplexers, powered by light switches, optical frequency and time domain reflectometry or reconfigurable optical filters, among others. New applications of traditional sensing structures or techniques have been also demonstrated. All of them focused on improving the performance of current sensors transducers, multiplexing networks and structural health monitoring applications. Thus, new point transducers have been developed: two of them are interferometric sensors based on photonic crystal fibers; and another one is based on a fiber ring resonator structure. Fiber optic sensor networks using commercial OTDRs have been also explored. On the one hand, different sensors have been successfully multiplexed in the same bus network. And, on the other hand, a FLM/LPG sensor was remotely interrogated at a distance of 253 km without using amplification. Random distributed feedback (RDFB) lasers have been explored for sensors interrogation. Two multi-wavelength Raman fiber lasers suitable for sensors interrogation have been demonstrated. Also, a random fiber laser has been internally modulated for the first time. Then, some experimental demonstrations of fiber optic sensors networks have been carried out taking into account the principal challenges they pose: multiplexing a number of optical sensors in a single networks, and enabling the possibility of remote sensing. Firstly, intensity sensors using TDM technology have been multiplexed. Secondly, PCF sensors have been successfully multiplexed. Thirdly, three new approaches to enable remote sensing are presented. Finally, a remote powered by light fiber optic switch have been included in three networks in order to add robustness and multiplexing versatility.Este trabajo se ha llevado a cabo gracias a las aportaciones económicas recibidas de los siguientes organismos, entre otros: - Secretaría de Estado de Investigación, Desarrollo e Innovación, Ministerio de Economía y Competitividad de España a través del programa de Formación del Personal Investigador y asociado al proyecto de investigación TEC2010-20224-C02-01. - Universidad Pública de Navarra mediante las ayudas a tesis doctorares. - Acción Europea COST- TD1001: Novel and Reliable Optical Fibre Sensor Systems for Future Security and Safety Applications (OFSeSa) - También se ha recibido financiación del Proyecto de Investigación de la Secretaría de Estado de Investigación, Desarrollo e Innovación, Ministerio de Economía y Competitividad de España TEC2013-47264-C2-2-R, de Innocampus, del Proyecto Europeo SUDOE-ECOAL-Intereg Project ECOAL-MGT y de los Fondos FEDER.Programa Oficial de Doctorado en Tecnologías de las Comunicaciones (RD 1393/2007)Komunikazioen Teknologietako Doktoretza Programa Ofiziala (ED 1393/2007

Signal Enhancement Strategies in Classical Electrochemiluminescence Techniques for Modern Biosensing

With the ascent of IT, and since Ashton has invented the term Internet of Things (IoT) in 1999, this future idea of connected machines that can do tasks and perform decision-control cycles without human input has become more and more attractive and is today an established future scenario. Obviously, in an IoT, “sensors for everything” are one crucial corner stone of its existence and Analytical chemistry can and must deliver them. While many challenges towards a functioning IoT remain, we are on the verge of its beginning. This can be also seen with “Analytics 4.0” in research and on the market, tending to more IT-connected, portable, easier-controllable and integrated solutions. The entrance of mobility in the health sector or Point-of-Care (POC) diagnostics trends are alike influencing biosensing. Whether in mobile solutions or lab- and clinical environments, versatile, powerful and easy-to-adapt detection strategies like Electrochemiluminescence (ECL) are an attractive option. The ECL molecules [Ru(bpy)3]2+ and luminol represent the most prominent and most abundantly investigated luminophores for ECL since Bard’s accomplishment to make ECL a well-known technique. Because both are also two of the most efficient ECL emitters that can be well-handled in bioanalysis, and are available on the market, they are still today frequently used in research and also commercial applications. To cope with current benchmarks of sensitive detection, however a combination with a certain signal enhancement strategy is recommended. Several different routes can here be employed and one option is dendrimers. PAMAM dendrimers can function as ECL coreactant in [Ru(bpy)3]2+-ECL via their amino groups and at the same time expose primary amino groups as possible bioconjugation elements. Exploring this multi-functionality of the dendrimers was investigated here. This was done on a model system employing PAMAM dendrimers with [Ru(bpy)3]2+-ECL together with biotin/streptavidin as biorecognition element and analyte, respectively. The dendrimer’s bi-functionality was successfully proven and a joint-role of a biorecognition element and a possible reporter function suggests an optimum application in homogeneous assays. A different toolset for ECL signal enhancement is offered by liposomes. Numerous signaling molecules can be encapsulated inside the inner cavity of these synthetic vesicles, while they provide protection from the environment and connection-functionality to probes via lipids and surface groups on the outside. That application was here explored, together with a newly synthesized luminol derivative obtained by a simple synthesis route from commercial starting materials and exhibiting a four times increased ECL efficiency versus standard luminol. That was necessary as a liposome enhancement was denied for the standard luminol through its poor aqueous solubility. The new m-carboxy luminol considerably improved this feature which allowed its own encapsulation in liposomes. The superior signal generation with this dual system was proven in a model sandwich hybridization assay which yielded a 150-times better detection performance than the equal fluorescence-based assay while being almost zero affected through matrices like serum, soil or river water. As such the good performance of luminol ECL together with liposomes for highly sensitive detection applications was demonstrated. A further necessary element with liposomal amplification, are surfactants to set free the signaling molecules. However, this case depicts only one example of a multitude of applications of surfactants in bioassays and biochemical methods. Hence, surfactants are commonly present solution constituents which also have to be considered in general with ECL because they can influence the ECL signals positively or negatively. This was further investigated for luminol ECL by exploring the effect of 13 different surfactants on the luminol ECL efficiency on four different electrode materials. A deeper understanding of the distinct effects was obtained by looking into ECL emission behavior, electrochemical effects, the surfaces and Chemiluminescence effects. After all, the revelation of a complicated mechanism that involves many contributing factors and as such directs signal quenching or enhancement is an important finding for assay design. In this way, the selection of a suitable surfactant is possible to exploit maximum reachable signal efficiencies. A combination of signal enhancement tools like a better ECL molecule derivative, dendrimers, liposomes or surfactants has proven to boost the ECL performance considerably. A further means of signal enhancement is offered via miniaturization, which also makes the detection method better suited towards common application as liquid handling and easier automation are on hand. This can be used for single ECL assays or combinations of different ECL reagents in one system for multi-detection. Different strategies for the miniaturization of an ECL readout-capable system were investigated, taking requirements for [Ru(bpy)3]2+ and luminol as ECL reporters into account. This includes materials, electrochemical demands and simple design. Here, ITO electrodes – while advantageous for luminol ECL could not convince with their performance in [Ru(bpy)3]2+-ECL. Alternatively, laser scribed graphene electrodes have shown to be promising candidates for a future miniaturized system encompassing both, luminol and [Ru(bpy)3]2+ as ECL systems. Ultimately, the different signal amplifying strategies, investigated in this work that can be applied standalone or combined, offer a great toolset for state-of-the-art ECL detection applications in research and also for possible commercial applications

Fabrication and Applications of Printed and Handwriting Electronics

The accelerating arrival of the Internet of Things (IoT) era creates a rapidly growing demand for printed electronic. As a low-cost and green substrate, cellulose paper has become the most attractive choice for the printing of sustainable and disposable electronics. However, manufacture of high quality circuits with high conductivity on cellulose paper remains a challenge due to the substrate’s high porosity and roughness. In this thesis, a method for facile fabrication of hybrid copper-fiber highly conductive features on low-cost cellulose paper with strong adhesion and enhanced bending durability is introduced. With three-dimensional electroless deposition (ELD) of copper, the as-fabricated circuits show ultra-low sheet resistance down to 0.00544 Ω/sq. Taking advantages of the porous structure of paper, together with the precise control of the inkjet droplets, highly conductive vertical interconnected accesses (VIAs) are fabricated for multilayered devices without physically drilling holes or depositing additional dielectric material. To further utilize the unique porous structure of cellulose paper, a scalable fabrication method for flexible, binder-free and all-solid-state supercapacitors is proposed based on the low-cost chemical engraving technique, to construct CuxO nanostructure in-situ on the three-dimensional metallized cellulose fiber structures. Benefitting from both the “2D Materials on 3D Structures” design and the binder-free nature of the fabricated electrodes, substantial improvements to electrical conductivity, aerial capacitance, and electrochemical performance of the resulting supercapacitors (SCs) are achieved, fulfilling the increasing demand of highly customized power systems in the IoT and wearable electronics industries. The above-mentioned work all use inkjet printing for materials deposition. However, as a solvent-based printing technique, inkjet printer has strict requirement of ink properties and suffer from inevitable nozzle clogging. To address these challenges, a fabrication method based on solvent-free laser printing technique is proposed, pushing the manufacture of printed electronics towards an environmentally benign and more cost-efficient manor. Lastly, a one-step react-on-demand (RoD) method for fabricating flexible circuits with ultra-low sheet resistance, enhanced safety and durability is proposed. With the special functionalized substrate, a real-time synthesize of the 3D metal-polymer (3DMP) conductive structure is triggered on demand. The as-fabricated silver traces show an ultralow sheet resistance down to 4 mΩ/sq

NASA Tech Briefs, September 2007

Topics covered include; Rapid Fabrication of Carbide Matrix/Carbon Fiber Composites; Coating Thermoelectric Devices To Suppress Sublimation; Ultrahigh-Temperature Ceramics; Improved C/SiC Ceramic Composites Made Using PIP; Coating Carbon Fibers With Platinum; Two-Band, Low-Loss Microwave Window; MCM Polarimetric Radiometers for Planar Arrays; Aperture-Coupled Thin-Membrane L-Band Antenna; WGM-Based Photonic Local Oscillators and Modulators; Focal-Plane Arrays of Quantum-Dot Infrared Photodetectors; Laser Range and Bearing Finder With No Moving Parts; Microrectenna: A Terahertz Antenna and Rectifier on a Chip; Miniature L-Band Radar Transceiver; Robotic Vision-Based Localization in an Urban Environment; Programs for Testing an SSME-Monitoring System; Cathodoluminescent Source of Intense White Light; Displaying and Analyzing Antenna Radiation Patterns; Payload Operations Support Team Tools; Space-Shuttle Emulator Software; Soft Real-Time PID Control on a VME Computer; Analyzing Radio-Frequency Coverage for the ISS; Nanorod-Based Fast-Response Pressure-Sensitive Paints; Capacitors Would Help Protect Against Hypervelocity Impacts; Diaphragm Pump With Resonant Piezoelectric Drive; Improved Quick-Release Pin Mechanism; Designing Rolling-Element Bearings; Reverse-Tangent Injection in a Centrifugal Compressor; Inertial Measurements for Aero-assisted Navigation (IMAN); Analysis of Complex Valve and Feed Systems; Improved Path Planning Onboard the Mars Exploration Rovers; Robust, Flexible Motion Control for the Mars Explorer Rovers; Solar Sail Spaceflight Simulation; Fluorine-Based DRIE of Fused Silica; Mechanical Alloying for Making Thermoelectric Compounds; Process for High-Rate Fabrication of Alumina Nanotemplates; Electroform/Plasma-Spray Laminates for X-Ray Optics; An Automated Flying-Insect Detection System; Calligraphic Poling of Ferroelectric Material; Blackbody Cavity for Calibrations at 200 to 273 K; KML Super Overlay to WMS Translator; High-Performance Tiled WMS and KML Web Server; Modeling of Radiative Transfer in Protostellar Disks; Composite Pulse Tube; Photometric Calibration of Consumer Video Cameras; Criterion for Identifying Vortices in High- Pressure Flows; Amplified Thermionic Cooling Using Arrays of Nanowires; Delamination-Indicating Thermal Barrier Coatings; Preventing Raman Lasing in High-Q WGM Resonators; Procedures for Tuning a Multiresonator Photonic Filter; Robust Mapping of Incoherent Fiber-Optic Bundles; Extended-Range Ultrarefractive 1D Photonic Crystal Prisms; Rapid Analysis of Mass Distribution of Radiation Shielding; Modeling Magnetic Properties in EZTB; Deep Space Network Antenna Logic Controller; Modeling Carbon and Hydrocarbon Molecular Structures in EZTB; BigView Image Viewing on Tiled Displays; and Imaging Sensor Flight and Test Equipment Software