Spacecraft Reed-Solomon downlink module

Apparatus and method for providing downlink frames to be transmitted from a spacecraft to a ground station. Each downlink frame includes a synchronization pattern and a transfer frame. The apparatus may comprise a monolithic Reed-Solomon downlink (RSDL) encoding chip coupled to data buffers for storing transfer frames. The RSKL chip includes a timing device, a bus interface, a timing and control unit, a synchronization pattern unit, and a Reed-Solomon encoding unit, and a bus arbiter

Upset Simulation and Training Initiatives for U.S. Navy Commercial Derived Aircraft

Militarized versions of commercial platforms are growing in popularity due to many logistical benefits in the form of commercial off-the-shelf (COTS) parts, established production methods, and commonality for different certifications. Commercial data and best practices are often leveraged to reduce procurement and engineering development costs. While the developmental and cost reduction benefits are clear, these militarized aircraft are routinely operated in flight at significantly different conditions and in significantly different manners than for routine commercial flight. Therefore they are at a higher risk of flight envelope exceedance. This risk may lead to departure from controlled flight and/or aircraft loss1. Historically, the risk of departure from controlled flight for military aircraft has been mitigated by piloted simulation training and engineering analysis of typical aircraft response. High-agility military aircraft simulation databases are typically developed to include high angles of attack (AoA) and sideslip due to the dynamic nature of their missions and have been developed for many tactical configurations over the previous decades. These aircraft simulations allow for a more thorough understanding of the vehicle flight dynamics characteristics at high AoA and sideslip. In recent years, government sponsored research on transport airplane aerodynamic characteristics at high angles of attack has produced a growing understanding of stall/post-stall behavior. This research along with recent commercial airline training initiatives has resulted in improved understanding of simulator-based training requirements and simulator model fidelity.2-5 In addition, inflight training research over the past decade has produced a database of pilot performance and recurrency metrics6. Innovative solutions to aerodynamically model large commercial aircraft for upset conditions such as high AoA, high sideslip, and ballistic damage, as well as capability to accurately account for scaling factors, is necessary to develop realistic engineering and training simulations. Such simulations should significantly reduce the risk of departure from controlled flight, loss of aircraft, and ease the airworthiness certification process. The characteristics of commercial derivative aircraft are exemplified by the P-8A Multi-mission Maritime Aircraft (MMA) aircraft, and the largest benefits of initial investigation are likely to be yielded from this platform. The database produced would also be utilized by flight dynamics engineers as a means to further develop and investigate vehicle flight characteristics as mission tactics evolve through the years ahead. This paper will describe ongoing efforts by the U.S. Navy to develop a methodology for simulation and training for large commercial-derived transport aircraft at unusual attitudes, typically experienced during an aircraft upset. This methodology will be applied to a representative Navy aircraft (P-8A) and utilized to develop a robust simulation that should accurately represent aircraft response in these extremes. Simulation capabilities would then extend to flight dynamics analysis and simulation, as well as potential training applications. Recent evaluations of integrated academic, ground-based simulation, and in-flight upset training will be described along with important lessons learned, specific to military requirements

Establishment of \u3ci\u3eListeria monocytogenes\u3c/i\u3e in the Gastrointestinal Tract

Listeria monocytogenes is a Gram positive foodborne pathogen that can colonize the gastrointestinal tract of a number of hosts, including humans. These environments contain numerous stressors such as bile, low oxygen and acidic pH, which may impact the level of colonization and persistence of this organism within the GI tract. The ability of L. monocytogenes to establish infections and colonize the gastrointestinal tract is directly related to its ability to overcome these stressors, which is mediated by the efficient expression of several stress response mechanisms during its passage. This review will focus upon how and when this occurs and how this impacts the outcome of foodborne disease

Assessing an Extension Plant Pest Diagnostic Center for Commercial Clients: Satisfaction, Savings, and Success

The descriptive-correlational study reported here sought to assess the effectiveness of the Extension Plant Pest Diagnostic Center (PPDC) for Tennessee\u27s commercial clients. These clients are served through one-on-one consultation regarding their individual plant or household and structural pest problems through submitted samples. The results from a mailed questionnaire showed that the majority of PPDC clients felt that the information was quick enough for their needs. While one-third of the 61 respondents stated that the PPDC recommendations saved them money, only one in 10 estimated the amount of money they saved. Suggestions for future PPDC evaluation studies are discussed

Representations of the fundamental group of a surface in PU(p,q) and holomorphic triples

We count the connected components in the moduli space of PU(p,q)-representations of the fundamental group for a closed oriented surface. The components are labelled by pairs of integers which arise as topological invariants of the flat bundles associated to the representations. Our results show that for each allowed value of these invariants, which are bounded by a Milnor-Wood type inequality, there is a unique non-empty connected component. Interpreting the moduli space of representations as a moduli space of Higgs bundles, we take a Morse theoretic approach using a certain smooth proper function on the Higgs moduli space. A key step is the identification of the function's local minima as moduli spaces of holomorphic triples. We prove that these moduli spaces of triples are non-empty and irreducible.Comment: 6 pages, to appear in C. R. Acad. Sci. Paris Ser. I Mat

Correlating Interlaminar Fatigue Fracture Behavior to NDE Parameters in Carbon/Epoxy Composites Containing Voids and Delamination

Carbon fiber composites have been increasingly used in aerospace, military, sports, automotive and other fields due to their excellent properties, including high specific strength, high specific modulus, corrosion resistance, fatigue resistance, and low thermal expansion coefficient. Delamination, or interlaminar fracture, is a serious failure mode leading to a loss in composite stiffness and strength. Manufacturing process defects such as voids degrade the fatigue life and delamination resistance of the composite. This study investigates the effect of voids on fatigue interlaminar fracture behavior of carbon fiber composites. Samples with different vacuum levels: 0%, 50% and 100% were fabricated by varying the vacuum in the hand layup vacuum bagging manufacturing process. Delamination and void content were investigated using eight different NDE methods: X-Ray laminography, X-Ray refraction, ultrasonic testing, high frequency eddy current imaging, pulse thermography, pulse phase thermography and lock- in-thermography and thermal conductivity measurements,. Then, the static interlaminar fracture behavior under Mode I and Mode II were conducted, as well as Mode I in fatigue. The results of X-Ray laminography, X-Ray Refraction, pulse thermography and pulse phase thermography were the most successful NDE technique for quantifying imperfections of the materials and for instance void shape, area fractions, size and distribution. However, X-Ray laminography gave the most accurate percentages of voids among the other NDE methods, as it provides hundreds of scanned images through the sample’s thickness with the most important advantage being the 3D representation. Thermal conductivity measurements showed that the voids lead to a decrease in thermal conductivity through-thickness. The ultrasonic method detected the delaminations but was not successful and quantifying the void content. The eddy current and lock-in-thermography were also not well-suited for detecting voids. Results of static Mode I and Mode II showed that voids can lead to a decrease in interlaminar fracture toughness. In addition, the presence of voids lead to a decrease in Mode I cyclic strain energy release rates fatigue life

The effectiveness of non-native fish eradication techniques in freshwater ecosystems: A systematic review protocol

Background: This systematic review will address the need for having a better understanding of the evidence-base for the effectiveness of different management techniques focussed on the eradication of non-native fish species in the freshwater environment. Many resource management agencies around the world attempt to eradicate non-native fish species to achieve management goals with respect to ecological integrity. There is a need to better understand the effectiveness of each management technique to provide resource managers with the information necessary to effectively manage aquatic resources, and to choose the best technique to yield desired outcomes given different ecological and biological conditions. The findings of this systematic review will inform evidence-based management and conservation activities for resource managers around the globe that deal with non-native fish eradication programs. Methods: This systematic review will search for, compile, summarize, and synthesize evidence on the effectiveness of fisheries management techniques used for the eradication of non-native fish species in global freshwater systems. The review will use public search engines and specialist websites, and will include both primary and grey literature. All studies that assess the effectiveness of a fish eradication technique, in freshwater, will be included in the review. Potential effect modifiers will be identified to obtain a better understanding of the factors that affect the success of different eradication techniques, given different environmental conditions and biological factors. Study quality will be assessed to allow for critical evaluation, including study design, confounding factors and statistical analysis. Data will be compiled into a narrative synthesis and a meta-analysis will be conducted where data availability and quality allow

The politics of pleasure : local government, tourism strategy and provision in Lancashire seaside resorts before and after 1974

This thesis examines the critical role of local government in the development and transformation of Lancashire’s major seaside resorts: Blackpool, Morecambe and Heysham, and Lytham St Annes. Through a detailed historical analysis, spanning from the early twentieth century to the present, it investigates how local authorities have navigated shifting political structures and evolving tourist markets, helping to shape the fortunes of these coastal destinations. The research contributes to the understanding of English seaside resort evolution by focusing on localised, place-specific factors, particularly the decision-making processes within local governments. Utilising a comparative approach, this thesis analyses the pivotal transitions in governance, especially post-1974, where increased centralisation altered the dynamics of local decision-making. It delineates how these shifts impacted the resorts' ability to adapt to changing tourism demands and socio-economic pressures.A key finding of this research is the demonstration of the long-term implications of local government actions on resort towns. It highlights that effective local governance, characterised by proactive, innovative strategies and strong public-private partnerships, can significantly influence the resilience and regeneration of tourist destinations. Conversely, inconsistent or ineffective local governance can lead to stagnation and decline, as illustrated in the varied experiences of the studied resorts. The thesis also addresses a notable gap in historiography by providing an in-depth exploration of the post-1974 period, a less examined era in the context of seaside resort development in the UK. In doing so, it offers new insights into the complexities of governance and its direct impact on local economies and cultural landscapes.This thesis draws upon a wide range of archival materials from across Lancashire, as well as utilising various digital collections. By combining historical survey data, policy analysis, and contemporary observations in both local and national media, this study not only adds depth to scholarly discussions in history, tourism studies, and public policy, but also offers insights for present and future urban and tourism planning. It highlights the crucial importance of local autonomy and community involvement in the preservation and regeneration of seaside resorts, underscoring the impact of localised decision-making on creating thriving and sustainable tourist destinations