374 research outputs found

    Thermal expansion and compressibility of rocks as a function of pressure and temperature

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    Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Science, 1982.Microfiche copy available in Archives and ScienceBibliography: leaves 42-44.by Harvey Hartman Haines.M.S

    Single-Receiver GPS Phase Bias Resolution

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    Existing software has been modified to yield the benefits of integer fixed double-differenced GPS-phased ambiguities when processing data from a single GPS receiver with no access to any other GPS receiver data. When the double-differenced combination of phase biases can be fixed reliably, a significant improvement in solution accuracy is obtained. This innovation uses a large global set of GPS receivers (40 to 80 receivers) to solve for the GPS satellite orbits and clocks (along with any other parameters). In this process, integer ambiguities are fixed and information on the ambiguity constraints is saved. For each GPS transmitter/receiver pair, the process saves the arc start and stop times, the wide-lane average value for the arc, the standard deviation of the wide lane, and the dual-frequency phase bias after bias fixing for the arc. The second step of the process uses the orbit and clock information, the bias information from the global solution, and only data from the single receiver to resolve double-differenced phase combinations. It is called "resolved" instead of "fixed" because constraints are introduced into the problem with a finite data weight to better account for possible errors. A receiver in orbit has much shorter continuous passes of data than a receiver fixed to the Earth. The method has parameters to account for this. In particular, differences in drifting wide-lane values must be handled differently. The first step of the process is automated, using two JPL software sets, Longarc and Gipsy-Oasis. The resulting orbit/clock and bias information files are posted on anonymous ftp for use by any licensed Gipsy-Oasis user. The second step is implemented in the Gipsy-Oasis executable, gd2p.pl, which automates the entire process, including fetching the information from anonymous ft

    Operation and Application of a Regional High-Frequency Radar Network in the Mid-Atlantic Bight

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    The Mid-Atlantic Regional Coastal Ocean Observing System (MARCOOS) High- Frequency Radar Network, which comprises 13 long-range sites, 2 medium-range sites, and 12 standard-range sites, is operated as part of the Integrated Ocean Observing System. This regional implementation of the network has been operational for 2 years and has matured to the point where the radars provide consistent coverage from Cape Cod to Cape Hatteras. A concerted effort was made in the MARCOOS project to increase the resiliency of the radar stations from the elements, power issues, and other issues that can disable the hardware of the system. The quality control and assurance activities in the Mid-Atlantic Bight have been guided by the needs of the Coast Guard Search and Rescue Office. As of May,, 2009, these quality-controlled MARCOOS High-Frequency Radar totals are being served through the Coast Guard\u27s Environmental Data Server to the Coast Guard Search and Rescue Optimal Planning System. In addition to the service to U.S. Coast Guard Search and Rescue Operations, these data support water quality, physical oceanographic, and fisheries research throughout the Mid-Atlantic Bight

    IPC2010-31419 BALANCING PIPELINE SAFETY AND COST INTEGRITY MANAGEMENT THROUGH PERFORMANCE VALIDATION OF IN-LINE INSPECTION DATA

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    ABSTRACT In-Line Inspection (ILI) surveys are widely employed to identify potential threats by capturing changes in pipe condition such as metal loss, caused by corrosion. The better the performance and interpretation of these survey data, the higher the reliability of being able to predict the actual condition of the pipe and required remediation. Each ILI survey has a certain level of conservatism from the assessment equations such as B31G and sensitivity to ILI performance for measurement uncertainty. Multiple levels of conservatism intended to limit the possibility of a non-conservative assessment can result in a significant economic penalty and excessive digs without improving safety. A study was undertaken to evaluate the reliability of responses to ILI corrosion features through multiple case studies examining the effects of failure criteria and data analysis parameters. This paper discusses the effect of validated ILI performance on safety, and addresses the risk of false acceptance of corrosion indications at a prescribed safety factor. The cost of unnecessary excavations due to falsely rejecting ILI predictions is also discussed

    The TeraGyroid Experiment

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    The TeraGyroid experiment at SC 03 addressed a large-scale problem of genuine scientific interest at the same time as showing how intercontinental grids enable new paradigms for collaborative computational science that can dramatically reduce the time to insight. TeraGyroid used computational steering to accelerate the exploration of parameter space in condensed matter simulations. The scientific objective was to study the self-assembly, defect pathways and dynamics of liquid crystalline cubic gyroid mesophases using the largest set of lattice-Boltzmann (LB) simulations ever performed, involving in some cases lattices of over one billion sites and for highly extended simulation times. We describe the application in sufficient detail to reveal how it uses the grid to support interactions between its distributed parts, where the interfaces exist between the application and the middleware infrastructure, what grid services and capabilities are used, and why important design decisions were made. We also describe how the resources of highend computing services were federated with the UK e-Science Grid and the US TeraGrid to form the TeraGyroid testbed, and summarise the lessons learned during the experiment

    Imagining the highway:Anticipating infrastructural and environmental change in Belize

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    This article examines the social and political, as well physical, construction of infrastructure, by attending to the implications of a highway yet to be built. In southern Belize, where the development of rural road networks figures strongly in historical narratives of political and environmental change, the recent paving of a major domestic highway has had distinctive implications for livelihoods and land rights among the predominantly Maya population of rural Toledo district. At the time of research, a plan for a new paved highway to the Guatemalan border animated longstanding debates over territoriality, environment and development, even as the details remained elusive. Bringing political ecology into conversation with attention to the perception of sensory environments, and the affective power of anticipation, I argue for extending anthropological conversations about infrastructure to encompass the meanings and consequences of imagined infrastructures for the ways people encounter, experience and enact social and environmental change

    Efficacy and safety of non-steroidal anti-inflammatory drugs (NSAIDs) for the treatment of acute pain after orthopedic trauma: a practice management guideline from the Eastern Association for the Surgery of Trauma and the Orthopedic Trauma Association

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    OBJECTIVES: Fracture is a common injury after a traumatic event. The efficacy and safety of non-steroidal anti-inflammatory drugs (NSAIDs) to treat acute pain related to fractures is not well established. METHODS: Clinically relevant questions were determined regarding NSAID use in the setting of trauma-induced fractures with clearly defined patient populations, interventions, comparisons and appropriately selected outcomes (PICO). These questions centered around efficacy (pain control, reduction in opioid use) and safety (non-union, kidney injury). A systematic review including literature search and meta-analysis was performed, and the quality of evidence was graded per the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. The working group reached consensus on the final evidence-based recommendations. RESULTS: A total of 19 studies were identified for analysis. Not all outcomes identified as critically important were reported in all studies, and the outcome of pain control was too heterogenous to perform a meta-analysis. Nine studies reported on non-union (three randomized control trials), six of which reported no association with NSAIDs. The overall incidence of non-union in patients receiving NSAIDs compared with patients not receiving NSAIDs was 2.99% and 2.19% (p=0.04), respectively. Of studies reporting on pain control and reduction of opioids, the use of NSAIDs reduced pain and the need for opioids after traumatic fracture. One study reported on the outcome of acute kidney injury and found no association with NSAID use. CONCLUSIONS: In patients with traumatic fractures, NSAIDs appear to reduce post-trauma pain, reduce the need for opioids and have a small effect on non-union. We conditionally recommend the use of NSAIDs in patients suffering from traumatic fractures as the benefit appears to outweigh the small potential risks

    Pressures towards and against formalization: Regulation and informal employment in Mozambique

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    The informal economy accounts for the bulk of employment in many emerging economies. Regulation theory suggests that all economic activity is characterized by a complex combination of formal and informal regulation. Looking at the case of Mozambique, this article explores the pressures towards and against formalization, and the forms regulation can take, drawing on qualitative research based on in-depth elite interviews and observation. The findings highlight how the State's role in promoting formalization of the informal economy is ambivalent; its approach incorporates both "progressive" elements, which focus on the modernization of regulations and institutions, and "conservative" elements, which inhibit this process of change

    The NIHR collaboration for leadership in applied health research and care (CLAHRC) for greater manchester: combining empirical, theoretical and experiential evidence to design and evaluate a large-scale implementation strategy

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    Background: In response to policy recommendations, nine National Institute for Health Research (NIHR) Collaborations for Leadership in Applied Health Research and Care (CLAHRCs) were established in England in 2008, aiming to create closer working between the health service and higher education and narrow the gap between research and its implementation in practice. The Greater Manchester (GM) CLAHRC is a partnership between the University of Manchester and twenty National Health Service (NHS) trusts, with a five-year mission to improve healthcare and reduce health inequalities for people with cardiovascular conditions. This paper outlines the GM CLAHRC approach to designing and evaluating a large-scale, evidence- and theory-informed, context-sensitive implementation programme. Discussion: The paper makes a case for embedding evaluation within the design of the implementation strategy. Empirical, theoretical, and experiential evidence relating to implementation science and methods has been synthesised to formulate eight core principles of the GM CLAHRC implementation strategy, recognising the multi-faceted nature of evidence, the complexity of the implementation process, and the corresponding need to apply approaches that are situationally relevant, responsive, flexible, and collaborative. In turn, these core principles inform the selection of four interrelated building blocks upon which the GM CLAHRC approach to implementation is founded. These determine the organizational processes, structures, and roles utilised by specific GM CLAHRC implementation projects, as well as the approach to researching implementation, and comprise: the Promoting Action on Research Implementation in Health Services (PARIHS) framework; a modified version of the Model for Improvement; multiprofessional teams with designated roles to lead, facilitate, and support the implementation process; and embedded evaluation and learning. Summary: Designing and evaluating a large-scale implementation strategy that can cope with and respond to the local complexities of implementing research evidence into practice is itself complex and challenging. We present an argument for adopting an integrative, co-production approach to planning and evaluating the implementation of research into practice, drawing on an eclectic range of evidence sources.Gill Harvey, Louise Fitzgerald, Sandra Fielden, Anne McBride, Heather Waterman, David Bamford, Roman Kislo and Ruth Boade
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