879 research outputs found

    Vibration responses of test structure no. 1 during the Edwards Air Force Base phase of the national sonic boom program

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    In order to evaluate reaction of people to sonic booms of varying overpressures and time durations, a series of closely controlled and systematic flight test studies were conducted in the vicinity of Edwards AFB, California, from June 3 to June 23, 1966. The dynamic responses of several building structures were measured as a part of these studies, and the measurements made in a one-story residence structure (Edwards test structure No. 1) are presented. Sample acceleration and strain recordings are presented from F-104, B-58, and XB-70 sonic-boom exposures, along with tabulations of the maximum acceleration and strain values measured for each one of about 140 flight tests. These data are compared with similar measurements for engine noise exposures of the building during simulated landing approaches and takeoffs of KC-135 aircraft

    Vibration Responses of Test Structure No. 2 During the Edward Air Force Base Phase of the National Sonic Boom Program

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    In order to evaluate reaction of people to sonic booms of varying overpressures and time durations, a series of closely controlled and systematic flight tests/studies were conducted from June 3 to June 23, 1966. The dynamic responses of several building structures were measured, with emphasis on a two-story residence structure. Sample acceleration and strain recordings from F-104, B-58, and XB-70 sonic boom exposures are included, along with tabulations of the maximum acceleration and strain values measured for each one of about 140 flight tests. These data are compared with similar measurements for engine noise exposures of the building during simulated landing approaches and takeoffs of KC-135 aircraft

    Comparison of measured and calculated aircraft lift generated pressures

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    Lift generated pressures produced by large, heavy aircraft at low altitudes were investigated due to concern over their possible effects on ground objects. Aircraft lift generated pressures were calculated using elementary airfoil theory, and these values were compared with ground level measurements made during an overflight program. The predicted and the measured values were in relatively good agreement. Due to lack of experimental investigations of this phenomenon, opportunity was taken during an overflight program to use a specially instrumented test range to measure the ground pressures produced for a range of aircraft weights and distances

    Land use change in a pericolonial society: intensification and diversification in Ifugao, Philippines between 1570 and 1800 CE

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    Land use modelling is increasingly used by archaeologists and palaeoecologists seeking to quantify and compare the changing influence of humans on the environment. In Southeast Asia, the intensification of rice agriculture and the arrival of European colonizers have both been seen as major catalysts for deforestation, soil erosion, and biodiversity change. Here we consider the Tuwali-Ifugao people of the Cordillera Central (Luzon, Philippines), who resisted Spanish colonial subjugation from the 16th to the mid-nineteenth century, in part through the development of a world-renowned system of intensive wet-rice terrace agriculture. To quantify changes in how the Tuwali-Ifugao used their environment, we model land use in Old Kiyyangan Village, a long-inhabited settlement, at two timepoints: circa 1570 CE, prior to the Spanish arrival in Luzon, and circa 1800 CE, before the village was sacked by Spanish military expeditions. Our model demonstrates that between 1570 and 1800 the adoption of rice as a staple and the corresponding expansion in terrace agriculture, along with a general diversification of diet and land use, enabled the village’s population to double without increasing total land use area. Further, this major intensification led to the solidification of social hierarchies and occurred without a proportional increase in deforestation.Introduction Methodology - Models in Ifugao: The History and Socio-Ecology of the Region - The Historical Land Use Model - Model Calculations for OKV - Population and Boble (Settled Area) at OKV - Payo (Terraces) - Uma (Swidden Fields) - Muyong (Private Forests) - Domesticated Animals - Hunting, Foraging, and Fishing - Fuel and Resource Extraction - Commerce - Agricultural Productivity and Nutritional Value - Dietary Proportions Results - 1800 - 1570 - Exploring Social Difference: Kadangyan and Nawotwot Land Use in 1800 Discussio

    Tidal Response of Mars Constrained From Laboratory-Based Viscoelastic Dissipation Models and Geophysical Data

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    We employ laboratory-based grain-size- and temperature-sensitive rheological models to 16 describe the viscoelastic behavior of terrestrial bodies with focus on Mars. Shear modulus 17 reduction and attenuation related to viscoelastic relaxation occur as a result of diffusion- 18 and dislocation-related creep and grain-boundary processes. We consider five rheological 19 models, including extended Burgers, Andrade, Sundberg-Cooper, a power-law approxima- 20 tion, and Maxwell, and determine Martian tidal response. However, the question of which 21 model provides the most appropriate description of dissipation in planetary bodies, re- 22 mains an open issue. To examine this, crust and mantle models (density and elasticity) are 23 computed self-consistently through phase equilibrium calculations as a function of pres- 24 sure, temperature, and bulk composition, whereas core properties are based on an Fe-FeS 25 parameterisation. We assess the compatibility of the viscoelastic models by inverting the 26 available geophysical data for Mars (tidal response and mean density and moment of in- 27 ertia) for temperature, elastic, and attenuation structure. Our results show that although 28 all viscoelastic models are consistent with data, their predictions for the tidal response at 29 other periods and harmonic degrees are distinct. The results also show that Maxwell is 30 only capable of fitting data for unrealistically low viscosities. Our approach can be used 31 quantitatively to distinguish between the viscoelastic models from seismic and/or tidal ob- 32 servations that will allow for improved constraints on interior structure (e.g., with InSight). 33 Finally, the methodology presented here is generally formulated and applicable to other so- 34 lar and extra-solar system bodies where the study of tidal dissipation presents an important 35 means for determining interior structure

    New Limits to the Infrared Background: Bounds on Radiative Neutrino Decay and on Contributions of Very Massive Objects to the Dark Matter Problem

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    From considering the effect of γ-γ interactions on recently observed TeV gamma-ray spectra, improved limits are set to the density of extragalactic infrared photons which are robust and essentially model independent. The resulting limits are more than an order of magnitude more restrictive than direct observations in the 0.025–0.3 eV regime. These limits are used to improve constraints on radiative neutrino decay in the mass range above 0.05 eV and to rule out very massive objects as providing the dark matter needed to explain galaxy rotation curves. Lower bounds on the maximum distance which TeV gamma rays may probe are also derived

    Searching for gravitational waves from known pulsars

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    We present upper limits on the amplitude of gravitational waves from 28 isolated pulsars using data from the second science run of LIGO. The results are also expressed as a constraint on the pulsars' equatorial ellipticities. We discuss a new way of presenting such ellipticity upper limits that takes account of the uncertainties of the pulsar moment of inertia. We also extend our previous method to search for known pulsars in binary systems, of which there are about 80 in the sensitive frequency range of LIGO and GEO 600.Comment: Accepted by CQG for the proceeding of GWDAW9, 7 pages, 2 figure

    Framework, principles and recommendations for utilising participatory methodologies in the co-creation and evaluation of public health interventions

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    Background: Due to the chronic disease burden on society, there is a need for preventive public health interventions to stimulate society towards a healthier lifestyle. To deal with the complex variability between individual lifestyles and settings, collaborating with end-users to develop interventions tailored to their unique circumstances has been suggested as a potential way to improve effectiveness and adherence. Co-creation of public health interventions using participatory methodologies has shown promise but lacks a framework to make this process systematic. The aim of this paper was to identify and set key principles and recommendations for systematically applying participatory methodologies to co-create and evaluate public health interventions. Methods: These principles and recommendations were derived using an iterative reflection process, combining key learning from published literature in addition to critical reflection on three case studies conducted by research groups in three European institutions, all of whom have expertise in co-creating public health interventions using different participatory methodologies. Results: Key principles and recommendations for using participatory methodologies in public health intervention co-creation are presented for the stages of: Planning (framing the aim of the study and identifying the appropriate sampling strategy); Conducting (defining the procedure, in addition to manifesting ownership); Evaluating (the process and the effectiveness) and Reporting (providing guidelines to report the findings). Three scaling models are proposed to demonstrate how to scale locally developed interventions to a population level. Conclusions: These recommendations aim to facilitate public health intervention co-creation and evaluation utilising participatory methodologies by ensuring the process is systematic and reproducible

    Search for Gravitational Waves from Primordial Black Hole Binary Coalescences in the Galactic Halo

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    We use data from the second science run of the LIGO gravitational-wave detectors to search for the gravitational waves from primordial black hole (PBH) binary coalescence with component masses in the range 0.2--1.0M⊙1.0 M_\odot. The analysis requires a signal to be found in the data from both LIGO observatories, according to a set of coincidence criteria. No inspiral signals were found. Assuming a spherical halo with core radius 5 kpc extending to 50 kpc containing non-spinning black holes with masses in the range 0.2--1.0M⊙1.0 M_\odot, we place an observational upper limit on the rate of PBH coalescence of 63 per year per Milky Way halo (MWH) with 90% confidence.Comment: 7 pages, 4 figures, to be submitted to Phys. Rev.
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