200,098 research outputs found
Torrent erosion in Lake District mountain catchments.
No full textThis thesis investigates torrent erosion in Lake District mountain catchments,Northern England. A nested research approach was used. Detailed investigations were undertaken at two case study sites (Iron Crag, Raise Beck) together with a survey of torrents across the Skiddaw and Helvellyn massifs.
At Iron Crag an annual sediment budget was constructed by monitoring hillslope,channel and fan processes. Particle size characteristics of sediments, and the history of fan development were investigated. Results show channel and bank sediments are the main source of material supplied to the fan. Large rainfall events cause significant change in the channel, banks and fan. The impact of different meteorological conditions on sediment characteristics is complex, however a seasonal cycle of sediment production (winter) and exhaustion (autumn) exists.
Historically, initial fan aggradation predates 36 BC, but a rapid phase of deposition began between 1200-1400 AD. Investigations at Raise Beck focussed on a flood that occurred in January 1995 and caused channel avulsion and shallow landsliding. This was reconstructed using a range of geomorphological and sedimentological evidence. Palaeohydrological methods give a discharge between 27- 74 in s-1. whereas as rainfall-runoff values range between 4-6 m3 s-1. The magnitude of the 1995 flood was smaller than two 19th Century events, but would still exceed the capacity of contemporary engineered channels.
The regional survey considered the characteristics and importance of torrents,mountain streams, and debris flows; and provided a context for work at the case
study sites. The case study sites are distinct members of the regional populations. Raise Beck being the largest (133 ha) and highest (858 m O. D. ); Iron Crag amongst
the smallest (2.4 ha) and lowest (600 m O. D. ). Overall, torrents and hillslope debris flows are minor components of the landscape (aerially 2.1 % Helvellyn massif, 0.4
% Skiddaw massif). Sites are preferentially located in regard to altitude and slope.Debris flows are related to geological type. Large torrent floods are relatively rare
and can be broadly related to regional flood episodes. Contemporary debris flow activity is of low magnitude and frequency
Cornellana (1.335 m.) des del Torrent de Cadí
No full textBoExcursió del 24 al 26 de juny de 1977. Itinerari: Organyà (558 m.) - Torà de Tost (1014 m.) - Selvanyà - Coll de Creus (1440 m.) - Adraén (1434 m.) - Cornellana (1335 m.) - Coll de Bacanella (1982 m.) - Ermita de Sant Salvador (1630 m.) Torrent de la Ginebreda - Adraén (1434 m.) - El Ges (1153 m.) - Puigcerdà (1202 m.
Improving P2P keyword search by combining .torrent metadata and user preference in a semantic overlay
No full textDeveloping a new similarity function for Tribler. Solution used a combination of item-item and user-user similarity, using metadata available in the .torrent files to reduce sparcity in dataset.Parallel and Distributed Systems groupElectrical Engineering, Mathematics and Computer Scienc
Methods for detecting channel bed surface changes in a mountain torrent – experiences from the Dorfbach torrent
No full textThe erosion of and depositions on channel bed surfaces are instrumental to
understanding debris flow processes. We present an overview of existing
field methods and highlight their respective advantages and disadvantages.
Terrestrial laser scanning (TLS), airborne laser scanning (ALS), erosion
sensors, cross sections (CS) and geomorphological mapping are compared.
Additionally, two of these approaches (i.e. TLS and CS) are tested and
applied in the channel reaches of the torrent catchments. The results of the
comparison indicate that the methods are associated with variable temporal
and spatial resolution as well as data quality and invested effort. TLS data
were able to quantify small-scale variations of erosion and deposition
volumes. While the same changes could be detected with CS and
geomorphological mapping, it was only possible with lower precision and
coarser spatial resolution. The study presents a range of potential methods
that can be applied accordingly to address the objectives and to support the
analyses of specific applications. The availability of erosion data,
acquired mainly by TLS and ALS, in combination with debris-flow monitoring
data, provides promising sources of information to further support torrent
risk management
Multi-temporal analysis to support the management of torrent control structures
No full textIn the last decade with increasing frequency of extreme weather events, an accurate, sustainable, and effective planning of torrent control structures has become essential to reduce hydro-geomorphic risk. Quite often in planning interventions, there is a lack of information on the effectiveness of existing structures, the evolution of the ongoing hydro-geomorphic process, and a priori in-depth study to analyze the sediment morphology dynamics and the interaction with possible existing torrent control structures. Nowadays, High-Resolution Topography data (HRT) greatly simplifies the monitoring of sediment morphology dynamics and the understanding of the interaction with torrent control structures over time. Therefore, thanks to repeated HRT surveys, it is possible to derive multi-temporal Digital Terrain Models (DTMs), and DTMs of Difference (DoDs) to quantify the morphological changes and study continuously the catchment morphodynamics. This information can be very valuable to support watershed management plans if combined with up-to-date field surveys that identify the existing torrent control structures, and asses their current status and functionality. The present work aims at introducing a methodological approach based on the integration of the sediment morphology dynamics data over large time spans (e.g., from 2003 to 2022), obtained by multi-temporal DoDs (realized from three DTMs at 1 m resolution), with an updating cadastre of torrent control structures enriched by a very simple, quick, and user-friendly Maintenance Priority index (MPi). The proposed workflow proved to be very useful in the test basins analysed, providing more complete data on torrent control structures and sediment dynamics evidence to stakeholders compared to the past. Moreover, it served as a proxy to assess the long-term effectiveness of the management interventions. The approach also helped to constantly identify the areas most prone to hazards, improve the intervention planning, and find more appropriate solutions or direct the maintenance works. Finally, the suggested workflow could be the starting point to outline up-to-date guidelines to be used in other catchments equipped with torrent control structures, emphasizing possible intervention priorities on where decision-makers could better invest resources. By providing current information and accurate tools to realize a more complete decision-making chain, which is often neglected, it is certainly possible to support more sustainable and effective risk management decisions
Les chironomides (Diptera) d'un torrent Pyrenéen de haute montagne : l'Estaragne
No full text61 espèces de Chironomides ont été capturées (à l'état imaginal et nymphal) dans le torrent froid d'Estaragne ; leurs périodes de vol sont précisées. Sur les 33 espèces rhéobiontes du peuplement, 9 sont abondantes. Diamesa hamaticornis et Eukiefferiella calvescens prédominent sur l'ensemble du réseau hydrographique.
Deux zones se distinguent de part et d'autre d'un ressaut glaciaire. La partie amont du torrent (> 2 130 m) présente les caractères d'un torrent glaciaire et une biocénose riche en Diamesini (6 espèces) caractérisée par Eukiefferiella fittkaui, Paratrichocladius skirwithensis, Diamesa zernyi. La partie aval (2 050-1 850 m) présente les caractères d'un torrent de haute montagne riche en Eukiefferiella (4 espèces) et caractérisée par Eukiefferiella minor et Pseudodiamesa branickii
Estudio de la evolución del sector agrario en el T. M. de Torrent (Valencia) durante el siglo XX
No full textLos objetivos del proyecto están fundamentalmente encaminados a la obtención de una
visión global sobre la evolución agraria en Torrent a lo largo del siglo XX, y en la elaboración de un
SIG que integre información agronómica desde 1900 hasta la actualidad.Rubio Ferri, A.; Martí Cortina, A. (2010). Estudio de la evolución del sector agrario en el T. M. de Torrent (Valencia) durante el siglo XX. Universitat Politècnica de València. https://riunet.upv.es/handle/10251/150855Archivo delegad
Estudi sobre la regeneració de la vegetació després de l incendi forestal dels Cims de Calicanto (Torrent, València)
No full text[ES] Se propone en este Trabajo de Final de Grado, realizar un estudio en las Cumbres de Calicanto (Torrent), sobre la regeneración natural de la cobertura vegetal después de haber sufrido una alteración, como es en este caso, un incendio forestal en abril de 2014.
Para ello, se conocerá la causa del incendio, el relieve, la litología, pendiente, vegetación... que había presente en la zona de estudio, para posteriormente, poder realizar un trabajo de campo, donde se elegirán 6 puntos representativos en la zona quemada (4) y en la zona no quemada (2), en cada parcela de 5 x 5 m, se realizará un inventario de la cobertura vegetal y número de ejemplares, para poder hacer una comparación entre una zona que ha sufrido una alteración respecto a la que no.
Y con toda la información obtenida, sacar resultados y conclusiones con las que poder proponer medidas de restauración o repoblación a raíz de la vegetación que se encuentra presente en ella.[EN] It is proposed in this Final Degree Project, to carry out a study in the Cumbres de Calicanto (Torrent), on the natural regeneration of the vegetation cover after having suffered a disturbance, as in this case, a forest fire in April 2014.
To do this, we will know the cause of the fire, the relief, lithology, slope, vegetation ... that was present in the study area, and then, to perform field work, where 6 representative points will be chosen in the burned area (4) and in the unburned area (2), in each plot of 5 x 5 m, an inventory of vegetation cover and number of specimens will be made, in order to make a comparison between an area that has suffered an alteration compared to the one that has not.
And with all the information obtained, draw results and conclusions with which to propose restoration or repopulation measures following the vegetation that is present in it.Gázquez García, M. (2022). Estudio sobre la regeneración de las especies vegetales tras el incendio forestal de las Cumbres Calicanto (Torrent, Valencia). Universitat Politècnica de València. https://riunet.upv.es/handle/10251/188979TFG
Organic Field-Effect Transistors Based on Ternary Blends Including a Fluorinated Polymer for Achieving Enhanced Device Stability
No full textThe stability of organic semiconductors (OSCs) is strongly hampered by the presence of water molecules. One approach that has been proved to lead to organic field-effect transistors with an enhanced performance is the use of blends of OSCs with insulating binding polymers. In this work, the fabrication of OSC thin films based on polymeric ternary blends including a hydrophobic fluorinated polymer is reported as a novel route to engineer long-term reliable organic field-effect transistors (OFET) devices. In particular, OFETs based on blends of bis(triisopropylsilylethynyl)pentacene (TIPS) with polystyrene (PS) and poly(pentafluorostyrene) (PFS) are explored. The PS:PFS ratio is tuned in order to find the optimum formulation. It is shown that films including 20% of PFS in the polymeric blend exhibit an improved device performance, which is reflected by a low bias stress and an exceptional environmental stability, without significantly hampering the OFET mobility. This work advocates that adding a small percentage of fluorinated polymers in OSC blends is a promising route to realize more reliable and stable devices without importantly compromising the device mobility
Lessive au bord du torrent dans les Andes de l'Equateur
No full textEn haute altitude, une femme lave le linge dans l'eau glacée du torrent. Séchage sur les rochers. 3 500 m à 4 000 m d'altitude. Vêtements de lainage coloré
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