295 research outputs found

    Spacecraft 2000

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    The objective of the Workshop was to focus on the key technology area for 21st century spacecraft and the programs needed to facilitate technology development and validation. Topics addressed include: spacecraft systems; system development; structures and materials; thermal control; electrical power; telemetry, tracking, and control; data management; propulsion; and attitude control

    Marshall Space Flight Center Research and Technology Report 2019

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    Today, our calling to explore is greater than ever before, and here at Marshall Space Flight Centerwe make human deep space exploration possible. A key goal for Artemis is demonstrating and perfecting capabilities on the Moon for technologies needed for humans to get to Mars. This years report features 10 of the Agencys 16 Technology Areas, and I am proud of Marshalls role in creating solutions for so many of these daunting technical challenges. Many of these projects will lead to sustainable in-space architecture for human space exploration that will allow us to travel to the Moon, on to Mars, and beyond. Others are developing new scientific instruments capable of providing an unprecedented glimpse into our universe. NASA has led the charge in space exploration for more than six decades, and through the Artemis program we will help build on our work in low Earth orbit and pave the way to the Moon and Mars. At Marshall, we leverage the skills and interest of the international community to conduct scientific research, develop and demonstrate technology, and train international crews to operate further from Earth for longer periods of time than ever before first at the lunar surface, then on to our next giant leap, human exploration of Mars. While each project in this report seeks to advance new technology and challenge conventions, it is important to recognize the diversity of activities and people supporting our mission. This report not only showcases the Centers capabilities and our partnerships, it also highlights the progress our people have achieved in the past year. These scientists, researchers and innovators are why Marshall and NASA will continue to be a leader in innovation, exploration, and discovery for years to come

    Optimization of maintenance performance for offshore production facilities

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    Master's thesis in Offshore technologyNew technologies are becoming advanced and complex for offshore production facilities. However this advancement and complexity in technology creates a more complicated and time consuming forensic processes for finding causes of failure, or diagnostic processes to identify events that reduce performance. As a result, micro-sensors, efficient signaling and communication technologies for collecting data efficiently, advanced software tools (such as fuzzy logic, neural networks, and simulation based optimization) have been developed, in parallel, to manage such complex assets. Given the nature and scale of ongoing changes on complexities, there are emerging concerns that increasing complexities, ill-defined interfaces, unforeseen events can easily lead to serious performance failures and major risks. To avoid such undesirable circumstances, „just-in-time‟ measures of performance to ensure fully functional is absolutely necessary. The increasing trend in complexity creates a motivation to develop an integrated maintenance management framework to get real-time information to solve problems quickly and hence to increase functional performance (help the asset to perform its required function effectively and efficiently while safeguarding life and the environment). Establishing “just-in-time” maintenance and repairs based on true machine condition maximizes critical asset useful life and eliminates premature replacement of functional components. This thesis focuses on developing an integrated maintenance management framework to establish „just-in-time‟ maintenance and to ensure continuous improvements based on maintenance domain experts as well as operational and historic data. To do this, true degradation of components must be identified. True level of degradation often cannot be inferred by the mere trending of condition indicator‟s level (CBM), because condition indicator levels are modulated under the influence of the diverse operating context. Besides, the maintenance domain expert does not have a precise knowledge about the correlation of the diverse operating context and level of degradation for a given level of condition indicator on specific equipment. Efforts have been made in here to identify the true degradation pattern of a component by analyzing these vagueness and imprecise knowledge. Key words: effective and efficient maintenance strategy, ‘just-in-time’ maintenance, condition based maintenance, P-F interval

    1-D broadside-radiating leaky-wave antenna based on a numerically synthesized impedance surface

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    A newly-developed deterministic numerical technique for the automated design of metasurface antennas is applied here for the first time to the design of a 1-D printed Leaky-Wave Antenna (LWA) for broadside radiation. The surface impedance synthesis process does not require any a priori knowledge on the impedance pattern, and starts from a mask constraint on the desired far-field and practical bounds on the unit cell impedance values. The designed reactance surface for broadside radiation exhibits a non conventional patterning; this highlights the merit of using an automated design process for a design well known to be challenging for analytical methods. The antenna is physically implemented with an array of metal strips with varying gap widths and simulation results show very good agreement with the predicted performance

    Beam scanning by liquid-crystal biasing in a modified SIW structure

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    A fixed-frequency beam-scanning 1D antenna based on Liquid Crystals (LCs) is designed for application in 2D scanning with lateral alignment. The 2D array environment imposes full decoupling of adjacent 1D antennas, which often conflicts with the LC requirement of DC biasing: the proposed design accommodates both. The LC medium is placed inside a Substrate Integrated Waveguide (SIW) modified to work as a Groove Gap Waveguide, with radiating slots etched on the upper broad wall, that radiates as a Leaky-Wave Antenna (LWA). This allows effective application of the DC bias voltage needed for tuning the LCs. At the same time, the RF field remains laterally confined, enabling the possibility to lay several antennas in parallel and achieve 2D beam scanning. The design is validated by simulation employing the actual properties of a commercial LC medium

    Establishment of a fully automatized microfluidic platform for the screening and characterization of novel Hepatitis B virus capsid assembly modulators

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    El procés de descobriment de fàrmacs s'enfronta a importants desafiaments a causa de la constant disminució dels guanys per medicament atesa la disminució en les noves aprovacions de la FDA combinada amb el constant augment dels costos i el temps de desenvolupament. Les plataformes integrades de detecció usant microfluídica van sorgir com a possibles solucions per accelerar el desenvolupament de molècules actives i reduir els requisits de temps i costos. El projecte VIRO-FLOW té com a objectiu identificar nous agents curatius per al virus de l'hepatitis B (VHB), integrant els avantatges de la química de flux continu amb tecnologies de bioassaigs in vitro en microfluídica. Durant aquesta tesi es va construir un sistema microfluídic aplicant dispositius modulars automatitzats. Es van redactar protocols d'avaluació per a les dades de fluorescència i reflexió, permetent el càlcul del factor Z, les desviacions estàndard, les corbes de dilució i els valors de concentracions efectives mitjanes màximes (EC50). La proteïna central del VHB (HBc) es va seleccionar com a objectiu principalEl proceso de descubrimiento de fármacos se enfrenta a importantes desafíos debido a la constante disminución de las ganancias por medicamento dada la disminución en las nuevas aprobaciones de la FDA combinada con el constante aumento de los costes y el tiempo de desarrollo. Las plataformas integradas de detección usando microfluídica surgieron como posibles soluciones para acelerar el desarrollo de moléculas activas y reducir los requisitos de tiempo y costes. El proyecto VIRO-FLOW tiene como objetivo la identificación de nuevos agentes curativos para el virus de la hepatitis B (VHB), integrando las ventajas de la química de flujo continuo con tecnologías de bioensayos in vitro en microfluídica. Durante la presente tesis se construyó un sistema microfluídico aplicando dispositivos modulares automatizados. Se redactaron protocolos de evaluación para los datos de fluorescencia y reflexión, permitiendo el cálculo del factor Z, desviaciones estándar, curvas de dilución y valores de concentraciones efectivas medias máximas (EC50). La proteína central del VHB (HBc) se seleccionó como objetivo principal.Drug Discovery as known today faces major challenges due to the constant decrease of earnings per drug given the decrease in new FDA approvements combined with the steadily rising development costs and time. Integrated microfluidic screening platforms emerged as possible solutions by accelerating the hit-to-lead development cycle and reducing time and cost requirements. The VIRO-FLOW project aims at the fast and efficient identification of novel curative agents for the Hepatitis B Virus (HBV), integrating the advantages of continuous flow chemistry with in vitro microfluidic bioassay technologies. During the present thesis a microfluidic system was built, applying automatized modular devices. Evaluation protocols were written for the fluorescence and reflection data, allowing the Z´-factor calculation, standard deviations, dilution curves, and half‐maximal effective concentrations (EC50) values. HBV core protein (HBc) was selected as primary target due to the ongoing demand for a functional cure to reduce the economic and social challenges imposed by the chronic diseas

    Fourier transform mass spectrometry at the uncertainty principle limit for improved qualitative and quantitative molecular analyses

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    Nowadays, among the instrumentation park of mass spectrometry, Fourier transform mass spectrometers (FTMS), including ion cyclotron resonance (ICR) and Orbitrap FTMS, provide the highest analytical performance for accurate measurements and mass resolution. Nevertheless, molecular analysis in currently challenging research areas, such as life and environmental sciences, necessitates further improvement of these analytical characteristics. In recent decades, a regular approach to address the problem behind the analytical performance was using increased electromagnetic fields. However, per a given increase of their magnitudes, that approach is currently requiring more and more resources, hence demonstrating its limited feasibility for tomorrow. Therefore, only a qualitative breakthrough in the underlying methodology may then lead to the next series of developments enabling improved molecular analysis. The present research is dedicated to the fundamental question behind the analytical performance in FTMS. Specifically, this thesis represents an interdisciplinary study aimed at improved molecular analysis in FTMS-based applications, achieved via better comprehension of the uncertainty principle in FTMS, viz. its dependence on the measurement scheme, including ion traps, signal processing, and data analysis, as well as its influence on achievable analytical characteristics in FTMS. To start, the uncertainty principle for measurements in FTMS has been investigated, asserting a limit to the precision with which complementary physical quantities in FTMS, e.g. detection period and scale of frequency details to resolve, can be measured. Specifically, two corollaries of the uncertainty principle are considered, viz. resolution performance and performance for accurate measurements in FTMS. Importantly, the uncertainty principle shows dependence on the particular measurement scheme employed. For instance, signal detection, signal processing, and data analysis of the standard measurement scheme impose their own restrictions to the resulting uncertainty principle, thus leading to the current limitations. However, the ultimate limitations in the analytical characteristics in question are defined by the uncertainty principle limit due to physics of ion motion in the mass analyzer. Hence, with corresponding developments in data analysis methods, methods for signal processing, and designs of ion traps, novel measurement schemes have been implemented, where the quantitative form of the uncertainty principle is modified towards the ultimate limit. Finally, the implemented solutions have been evaluated in the context of FTMS-based analysis of crude oil fractions, protein identification and characterization, quantitative proteomics, and analysis of isotopic fine structures of peptides. To conclude, the achieved success of this work should considerably contribute to the currently challenging analytical applications of FTMS

    Efficient Automated Driving Strategies Leveraging Anticipation and Optimal Control

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    Automated vehicles and advanced driver assistance systems bring computation, sensing, and communication technologies that exceed human abilities in some ways. For example, automated vehicles may sense a panorama all at once, do not suffer from human impairments and distractions, and could wirelessly communicate precise data with neighboring vehicles. Prototype and commercial deployments have demonstrated the capability to relieve human operators of some driving tasks up to and including fully autonomous taxi rides in some areas. The ultimate impact of this technology’s large-scale market penetration on energy efficiency remains unclear, with potential negative factors like road use by empty vehicles competing with positive ones like automatic eco-driving. Fundamentally enabled by historic and look-ahead data, this dissertation addresses the use of automated driving and driver assistance to optimize vehicle motion for energy efficiency. Facets of this problem include car following, co-optimized acceleration and lane change planning, and collaborative multi-agent guidance. Optimal control, especially model predictive control, is used extensively to improve energy efficiency while maintaining safe and timely driving via constraints. Techniques including chance constraints and mixed integer programming help overcome uncertainty and non-convexity challenges. Extensions of these techniques to tractor trailers on sloping roads are provided by making use of linear parameter-varying models. To approach the wheel-input energy eco-driving problem over generally shaped sloping roads with the computational potential for closed-loop implementation, a linear programming formulation is constructed. Distributed and collaborative techniques that enable connected and automated vehicles to accommodate their neighbors in traffic are also explored and compared to centralized control. Using simulations and vehicle-in-the-loop car following experiments, the proposed algorithms are benchmarked against others that do not make use of look-ahead information
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