989 resultados para Run-up
Resumo:
Large groundwater table fluctuations were observed in a coastal aquifer during an offshore storm. The storm induced significant changes of the mean shoreline elevation, characterized by a pulse-like oscillation. This pulse propagated in the aquifer, resulting in the water table fluctuations. A general analytical solution is derived to quantify this new mechanism of water table fluctuation. The solution is applied to field observations and is found to be able to predict reasonably well the observed storm-induced water table fluctuations. Based on the analytical solution, the damping characteristics and phase shift of the oscillation as it propagates inland are examined.
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New experimental laboratory data are presented on swash overtopping and sediment overwash on a truncated beach, approximating the conditions at the crest of a beach berm or inter-tidal ridge-runnel. The experiments provide a measure of the uprush sediment transport rate in the swash zone that is unaffected by the difficulties inherent in deploying instrumentation or sediment trapping techniques at laboratory scale. Overtopping flow volumes are compared with an analytical solution for swash flows as well as a simple numerical model, both of which are restricted to individual swash events. The analytical solution underestimates the overtopping volume by an order of magnitude while the model provides good overall agreement with the data and the reason for this difference is discussed. Modelled flow velocities are input to simple sediment transport formulae appropriate to the swash zone in order to predict the overwash sediment transport rates. Calculations performed with traditional expressions for the wave friction factor tend to underestimate the measured transport. Additional sediment transport calculations using standard total load equations are used to derive an optimum constant wave friction factor of f(w)=0.024. This is in good agreement with a broad range of published field and laboratory data. However, the influence of long waves and irregular wave run-up on the overtopping and overwash remains to be assessed. The good agreement between modelled and measured sediment transport rates suggests that the model provides accurate predictions of the uprush sediment transport rates in the swash zone, which has application in predicting the growth and height of beach berms. (c) 2005 Elsevier B.V. All rights reserved.
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This paper provides information on the experimental set-up, data collection methods and results to date for the project Large scale modelling of coarse grained beaches, undertaken at the Large Wave Channel (GWK) of FZK in Hannover by an international group of researchers in Spring 2002. The main objective of the experiments was to provide full scale measurements of cross-shore processes on gravel and mixed beaches for the verification and further development of cross-shore numerical models of gravel and mixed sediment beaches. Identical random and regular wave tests were undertaken for a gravel beach and a mixed sand/gravel beach set up in the flume. Measurements included profile development, water surface elevation along the flume, internal pressures in the swash zone, piezometric head levels within the beach, run-up, flow velocities in the surf-zone and sediment size distributions. The purpose of the paper is to present to the scientific community the experimental procedure, a summary of the data collected, some initial results, as well as a brief outline of the on-going research being carried out with the data by different research groups. The experimental data is available to all the scientific community following submission of a statement of objectives, specification of data requirements and an agreement to abide with the GWK and EU protocols. (C) 2005 Elsevier B.V. All rights reserved.
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This paper presents new laboratory data on the generation of long waves by the shoaling and breaking of transient-focused short-wave groups. Direct offshore radiation of long waves from the breakpoint is shown experimentally for the first time. High spatial resolution enables identification of the relationship between the spatial gradients of the short-wave envelope and the long-wave surface. This relationship is consistent with radiation stress theory even well inside the surf zone and appears as a result of the strong nonlinear forcing associated with the transient group. In shallow water, the change in depth across the group leads to asymmetry in the forcing which generates significant dynamic setup in front of the group during shoaling. Strong amplification of the incident dynamic setup occurs after short-wave breaking. The data show the radiation of a transient long wave dominated by a pulse of positive elevation, preceded and followed by weaker trailing waves with negative elevation. The instantaneous cross-shore structure of the long wave shows the mechanics of the reflection process and the formation of a transient node in the inner surf zone. The wave run-up and relative amplitude of the radiated and incident long waves suggests significant modification of the incident bound wave in the inner surf zone and, the dominance of long waves generated by the breaking process. It is proposed that these conditions occur when the primary short waves and bound wave are not shallow water waves at the breakpoint. A simple criterion is given to determine these conditions, which generally occur for the important case of storm waves.
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New laboratory scale experimental data are presented on the forcing of beach groundwater levels by wave run-up. The experimental setup simulates a coastal barrier dividing the ocean from a relatively constant back beach water level, conditions approximating a closed off lagoon system or beach aquifer. The data are critically compared to an advanced numerical model for simulating wave and beach groundwater interaction in the coastal zone, and provide the first experimental verification of such a model. Overall model-data comparisons are good, but some systematic discrepancies are apparent, and reasons for these are discussed.
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The Republic of Ireland and Northern Ireland were provided with aid to offset locational disadvantages in the run up to the Single European Market. Since then the Republic has emerged as the fastest growing member of the E.U. Success has not been underpinned by the transport system, suggesting that business has had to overcome locational disadvantages by strong performance elsewhere in the supply chain. The evidence indicates that there are Irish firms operating supply chain management techniques at a truly international standard. The problem is that there are so few in that category Meeting Ireland’s competitiveness challenge means closing the gap between the small group of large and foreign-owned firms, which display excellence in SCM, and the larger group of indigenous small and medium size businesses, which do not.
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This book examines the international development policies of five East Central European new EU member states, the Czech Republic, Hungary, Poland, Slovakia and Slovenia. These countries turned from being aid recipients to donors after the turn of the millennium in the run-up to EU accession in 2004. The book explains the evolution subsequent to EU accession and current state of foreign aid policies in the region and the reasons why these deviate from many of the internationally agreed best practices in development cooperation. It argues that after the turn of the millennium, a 'Global Consensus' has emerged on how to make foreign aid more effective for development. A comparison between the elements of the Global Consensus and the performance of the five countries reveals that while they have generally implemented little of these recommendations, there are also emerging differences between the countries, with the Czech Republic and Slovenia clearly aspiring to become globally responsible donors. Building on the literatures on foreign policy analysis, international socialization and interest group influence, the book develops a model of foreign aid policy making in order to explain the general reluctance of the five countries in implementing international best practices, and also the differences in their relative performance.
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While language use has been argued to reflect gender asymmetry, increasing parity has been evidenced in official settings (Holmes, 2000; Dister and Moreau, 2006). Our hypothesis is that the French national press has developed a norm of equal linguistic treatment of men and women. In a corpus of articles from Libération, Le Monde, and Le Figaro, we examine the treatment of Arlette Laguiller, the female leader of the French extreme-left 'Worker's Struggle' Party (Lutte Ouvrière), during the run-up to the 2007 presidential elections. How Laguiller is referred to and described in comparison with her male counterparts evidences no asymmetry. Breaches to parity are only found in the right-wing Figaro newspaper. The ideological distance between the newspaper and the candidate suggests that power struggles are a primary source of asymmetrical treatments. The discursive functions of such treatments can be understood through an investigation based on a portable corpus linguistics methodology for the measure of discrimination. © 2011 Elsevier B.V.
Resumo:
Sporadic lack of consumer articles, the housing shortage, disturbances of material supply, and shortages of investment goods and of labour may be traced back to a common main cause. Shortage is constantly reproduced by specific features of the economic mechanism. The first part of the article consists of micro-analysis, mainly of the productive enterprise. Efforts to increase production may run up against ceilings of three kinds: constraints on physical resources, constraints on demand, and the budget constraint on enterprises. It is an important feature of a system which of these constraints takes effect. Resource-constrained systems can be distinguished from demand-constrained ones here. In the former, production is limited by production bottlenecks, in the latter by buyer demand. The socialist economy in its "classical" form belongs to the former type. It is related to whether the budget constraint on the enterprise is "hard" or "soft". If hard, enterprise spending is limited by its financial scope, if soft (its losses offset almost automatically) its demand becomes almost insatiable. The second part performs a macro-analysis, showing the mechanism of "suction" with the aid of a hydraulic analogy. The enterprise sector "pumps away" reserves and surpluses of the system, mainly due to the "investment hunger" that appears in the wake of expansionist efforts. Finally the article discusses briefly the interrelations between shortage and inflation.
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The delegation of public tasks to arm’s-length bodies remains a central feature of contemporary reform agendas within both developed and developing countries. The role and capacity of political and administrative principals (i.e. ministers and departments of state) to control the vast network of arm’s-length bodies for which they are formally responsible is therefore a critical issue within and beyond academe. In the run-up to the 2010 General Election in the United Kingdom, the ‘quango conundrum’ emerged as an important theme and all three major parties committed themselves to shift the balance of power back towards ministers and sponsor departments. This article presents the results of the first major research project to track and examine the subsequent reform process. It reveals a stark shift in internal control relationships from the pre-election ‘poor parenting’ model to a far tighter internal situation that is now the focus of complaints by arm’s-length bodies of micro-management. This shift in the balance of power and how it was achieved offers new insights into the interplay between different forms of governance and has significant theoretical and comparative relevance. Points for practitioners: For professionals working in the field of arm’s-length governance, the article offers three key insights. First, that a well-resourced core executive is critical to directing reform given the challenges of implementing reform in a context of austerity. Second, that those implementing reform will also need to take into account the diverse consequences of centrally imposed reform likely to result in different departments with different approaches to arm’s-length governance. Third, that reforming arm’s-length governance can affect the quality of relationships, and those working in the field will need to mitigate these less tangible challenges to ensure success.
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Extracts from a treatise in which Locke sets out his labour theory of property.
Locke's writings on the labour theory of property provided eighteenth century proponents of the concept of copyright at common law (that is, copyright as a natural authorial property right) with a philosophical basis upon which to develop their arguments. The commentary explores the significance of a series of correspondence between John Locke and Edward Clarke, then MP for Taunton, concerning the lapse of the Licensing Act 1662 (uk_1662), and in the run up to the passing of the Statute of Anne 1710 (uk_1710). The commentary argues that, regardless of how Locke's writings on property were subsequently co-opted in the mid-eighteenth century debates as to the nature of copyright, it is doubtful whether Locke himself considered that copyright existed at common law.
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Thesis (Ph.D.)--University of Washington, 2016-07
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The fisheries sector is vital to the Philippine economy, providing substantial employment and income, contributing export earnings, and meeting local food security and nutrition requirements. To protect coastal and marine habitat and to sustain fisheries, over 1000 marine protected areas (MPAs) have been established, in the Philippines. This paper provides empirical evidence on the variance of net revenues linked with MPA establishment and the possible range of relocation costs for fishing effort displaced by an MPA. A total of 424 households were randomly selected from 18 barangays (villages) adjacent to MPAs in three regions in the Philippines. Results show that incomes decrease significantly for both fulltime and seasonal types of fishers after 1-3 years of MPA establishment. The loss occurring through MPA is higher than expected and at least on the short run (up to 4 years) the spill-over effect does not compensate. This information helped to determine the necessary conditional cash transfers for coastal communities who are highly dependent on coastal and marine resources.
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We report sedimentological evidence for a tsunami from a coastal lake at Innaarsuit, Disko Bugt (west Greenland), which was most likely generated by a rolling iceberg. The tsunami invaded the lake c. 6000 years ago, during a period of time when relative sea level (RSL) was falling quickly because of isostatic rebound. We use the background rate of RSL fall, together with an age model for the sediment sequence, to infer a minimum wave run-up during the event of c. 3.3 m. The stratigraphic signature of the event bears similarities to that described from studies of the early-Holocene Storegga slide tsunami in Norwegian coastal basins. Conditions conducive to iceberg tsunami include a supply of icebergs, deep water close to the shore, a depositional setting protected from storms or landslide tsunami, and a coastal configuration that has the potential to amplify the height of tsunami waves as water depths shallow and the waves approach and impact the coast. Future warming of polar regions will lead to increased calving and iceberg production, at a time when human use of polar coasts will also grow. We predict, therefore, that iceberg-generated tsunami will become a growing hazard in polar coastal waters, especially in areas adjacent to large, fast-flowing, marine-terminating ice streams that are close to human populations or infrastructure.
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Tsunamis are highly energetic events that may destructively impact the coast. Resolving the degree of coastal resilience to tsunamis is extremely difficult and sometimes impossible. In part, our understanding is constrained by the limited number of contemporaneous examples and by the high dynamism of coastal systems. In fact, longterm changes of coastal systems can mask the evidence of past tsunamis, leaving us a short or incomplete sedimentary archive. Here, we present a multidisciplinary approach involving sedimentological, geomorphological and geophysical analyses and numerical modelling of the AD 1755 tsunami flood on a coastal segment located within the southern coast of Portugal. In particular, the work focuses on deciphering the impact of the tsunami waves over a coastal sand barrier enclosing two lowlands largely inundated by the tsunami flood. Erosional features documented by geophysical data were assigned to the AD 1755 eventwith support of sedimentological and age estimation results. Furthermore, these features allowed the calibration of the simulation settings to reconstruct the local conditions and establish the run-up range of the AD 1755 tsunami when it hit this coast (6– 8 m above mean sea level). Our work highlights the usefulness of erosional imprints preserved in the sediment record to interpret the impact of the extreme events on sand barriers