123 research outputs found
Surface water flood forecasting for urban communities
Key findings and recommendations:
• This research has addressed the challenge of surface water flood forecasting by producing the UK’s first operational surface water flood risk forecast with a 24-hour lead time. This was successfully used in Glasgow at the Commonwealth Games in 2014.
• The methodology of the Glasgow Pilot has been developed to use nationally available datasets and a transferrable approach which will help urban areas in Scotland improve their resilience to and preparedness for future flooding.
• It also delivered a novel method for forecasting the impacts of flooding in real-time and increased knowledge on communicating uncertainties in flood risk.
• A real-time forecasting system for surface water flooding from intense rainfall needs to use models that represent surface runoff production, surface water inundation and movement, and how water travels via surface and sub-surface pathways, including urban sewerage and drainage networks. Ensemble rainfall prediction models are key to quantifying uncertainty in forecasting the rainfall that causes surface water flooding.
• Detailed surface water flood inundation models exist and are widely used in design and research activities, but none were found to be ready for real-time use. The Grid-to-Grid (G2G) distributed hydrological model was chosen for used in the Glasgow Pilot as it can provide ensemble forecasts of surface water flooding, and takes account of the intensity and pattern of rainfall, land cover and slope, and antecedent conditions.
• The research developed a novel methodology for impact assessment that links surface runoff to the severity of flooding impacts on people, property and transport. Use is made of a library of information based on SEPA’s Regional Pluvial (rainfall-related) Flood Hazard maps.
• For the Glasgow Pilot, G2G was operated over a 10km by 10km area encompassing Glasgow’s East End and the main areas of activity for the 2014 Commonwealth Games. The research team developed an operational application, called FEWS Glasgow, to support running the model in real-time and reporting on the likely impacts of surface water flooding. A new Daily Glasgow Daily Surface Water Flood Forecast was designed and produced based on operational requirements and emergency responder feedback
Improved SOT (Hinode mission) high resolution solar imaging observations
We consider the best today available observations of the Sun free of
turbulent Earth atmospheric effects, taken with the Solar Optical Telescope
(SOT) onboard the Hinode spacecraft. Both the instrumental smearing and the
observed stray light are analyzed in order to improve the resolution. The Point
Spread Function (PSF) corresponding to the blue continuum Broadband Filter
Imager (BFI) near 450 nm is deduced by analyzing i/ the limb of the Sun and ii/
images taken during the transit of the planet Venus in 2012. A combination of
Gaussian and Lorentzian functions is selected to construct a PSF in order to
remove both smearing due to the instrumental diffraction effects (PSF core) and
the large-angle stray light due to the spiders and central obscuration (wings
of the PSF) that are responsible for the parasitic stray light. A
Max-likelihood deconvolution procedure based on an optimum number of iterations
is discussed. It is applied to several solar field images, including the
granulation near the limb. The normal non-magnetic granulation is compared to
the abnormal granulation which we call magnetic. A new feature appearing for
the first time at the extreme- limb of the disk (the last 100 km) is discussed
in the context of the definition of the solar edge and of the solar diameter. A
single sunspot is considered in order to illustrate how effectively the
restoration works on the sunspot core. A set of 125 consecutive deconvolved
images is assembled in a 45 min long movie illustrating the complexity of the
dynamical behavior inside and around the sunspot.Comment: 15 pages, 22 figures, 1 movi
Small-scale solar magnetic fields
As we resolve ever smaller structures in the solar atmosphere, it has become
clear that magnetism is an important component of those small structures.
Small-scale magnetism holds the key to many poorly understood facets of solar
magnetism on all scales, such as the existence of a local dynamo, chromospheric
heating, and flux emergence, to name a few. Here, we review our knowledge of
small-scale photospheric fields, with particular emphasis on quiet-sun field,
and discuss the implications of several results obtained recently using new
instruments, as well as future prospects in this field of research.Comment: 43 pages, 18 figure
Multiwavelength studies of MHD waves in the solar chromosphere: An overview of recent results
The chromosphere is a thin layer of the solar atmosphere that bridges the
relatively cool photosphere and the intensely heated transition region and
corona. Compressible and incompressible waves propagating through the
chromosphere can supply significant amounts of energy to the interface region
and corona. In recent years an abundance of high-resolution observations from
state-of-the-art facilities have provided new and exciting ways of
disentangling the characteristics of oscillatory phenomena propagating through
the dynamic chromosphere. Coupled with rapid advancements in
magnetohydrodynamic wave theory, we are now in an ideal position to thoroughly
investigate the role waves play in supplying energy to sustain chromospheric
and coronal heating. Here, we review the recent progress made in
characterising, categorising and interpreting oscillations manifesting in the
solar chromosphere, with an impetus placed on their intrinsic energetics.Comment: 48 pages, 25 figures, accepted into Space Science Review
Clusters of galaxies: setting the stage
Clusters of galaxies are self-gravitating systems of mass ~10^14-10^15 Msun.
They consist of dark matter (~80 %), hot diffuse intracluster plasma (< 20 %)
and a small fraction of stars, dust, and cold gas, mostly locked in galaxies.
In most clusters, scaling relations between their properties testify that the
cluster components are in approximate dynamical equilibrium within the cluster
gravitational potential well. However, spatially inhomogeneous thermal and
non-thermal emission of the intracluster medium (ICM), observed in some
clusters in the X-ray and radio bands, and the kinematic and morphological
segregation of galaxies are a signature of non-gravitational processes, ongoing
cluster merging and interactions. In the current bottom-up scenario for the
formation of cosmic structure, clusters are the most massive nodes of the
filamentary large-scale structure of the cosmic web and form by anisotropic and
episodic accretion of mass. In this model of the universe dominated by cold
dark matter, at the present time most baryons are expected to be in a diffuse
component rather than in stars and galaxies; moreover, ~50 % of this diffuse
component has temperature ~0.01-1 keV and permeates the filamentary
distribution of the dark matter. The temperature of this Warm-Hot Intergalactic
Medium (WHIM) increases with the local density and its search in the outer
regions of clusters and lower density regions has been the quest of much recent
observational effort. Over the last thirty years, an impressive coherent
picture of the formation and evolution of cosmic structures has emerged from
the intense interplay between observations, theory and numerical experiments.
Future efforts will continue to test whether this picture keeps being valid,
needs corrections or suffers dramatic failures in its predictive power.Comment: 20 pages, 8 figures, accepted for publication in Space Science
Reviews, special issue "Clusters of galaxies: beyond the thermal view",
Editor J.S. Kaastra, Chapter 2; work done by an international team at the
International Space Science Institute (ISSI), Bern, organised by J.S.
Kaastra, A.M. Bykov, S. Schindler & J.A.M. Bleeke
Propuesta de alternativa para la pacificación del tránsito frente a la sede 13 (calle 47 entre las carreras 13 y 14) de la Universidad Católica de Colombia
Trabajo de investigaciónEste proyecto busca generar espacios seguros para los peatones, con el fin de reducir los accidentes de tránsito, que al año 2018 según datos del IDECA, en la intersección de la carrera 13 con calle 47 se establecieron en 13.
Gracias a las diferentes alternativas de pacificación del tránsito que se encuentran disponibles en la actualidad, se ha logrado disminuir los accidentes de tránsito, es por esto, que en esta investigación se propone diseñar un paso a nivel sobre la calle 47 entre Carreras 13 y 14, con el fin de ampliar las vías peatonales basándose en la cartilla de andenes para Bogotá de la Secretaria Distrital De Planeación y el Decreto 327 del 2004. De igual manera se verifico el nivel de servicio actual del andén del costado norte y el nivel de servicio que se prestará con las alternativas propuestas, finalmente se llevó a cabo una simulación de la condición actual de movilidad del corredor con el fin de determinar cómo se comportara el corredor con la alternativa planteada en la investigación.
Todas las conclusiones de la investigación se basan en mejorar las condiciones de movilidad peatonal con el fin de conseguir una movilidad más segura y que no represente conflicto entre los diferentes actores viales del corredor.INTRODUCCIÓN
1. ANTECEDENTES Y JUSTIFICACIÓN
2. PLANTEAMIENTO Y FORMULACIÓN DEL PROBLEMA
3. OBJETIVOS
4. MARCO DE REFERENCIA
5. ALCANCES Y LIMITACIONES
6. METODOLOGÍA
7. VISITA DE CAMPO
8. INSPECCIÓN VISUAL DE SEGURIDAD
9. ESTUDIO DE LA ALTERNATIVA
10. DISEÑO DE LA ALTERNATIVA
11. MODELACIÓN EN PTV VISSIM 2020 VERSIÓN EDUCATIVA
12. CONCLUSIONES
BIBLIOGRAFÍA
ANEXOSPregradoIngeniero Civi
Search for gravitational waves from Scorpius X-1 in the second Advanced LIGO observing run with an improved hidden Markov model
We present results from a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to track spin wandering. This search improves on previous HMM-based searches of LIGO data by using an improved frequency domain matched filter, the J-statistic, and by analyzing data from Advanced LIGO's second observing run. In the frequency range searched, from 60 to 650 Hz, we find no evidence of gravitational radiation. At 194.6 Hz, the most sensitive search frequency, we report an upper limit on gravitational wave strain (at 95% confidence) of h095%=3.47×10-25 when marginalizing over source inclination angle. This is the most sensitive search for Scorpius X-1, to date, that is specifically designed to be robust in the presence of spin wandering. © 2019 American Physical Society
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