20 resultados para flooding

em Aston University Research Archive


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Purpose: Amidst the current economic climate, which places many constraints on expensive flood defence schemes, the policy makers tend to favour schemes that are sympathetic to the needs of small and medium-sized enterprises (SMEs) and which promote empowering local communities based on their individual local contexts. Research has shown that although several initiatives are in place to create behavioural change among SMEs in undertaking adaptation approaches against flooding, they often tend to delay their responses by means of a "wait and see" attitude. The paper aims to discuss these issues. Design/methodology/approach: This paper argues that unless there are conscious efforts in the policy-making community to undertake explicit measures to engage with SMEs in a collaborative way, the uptake of adaptation measures will not be achieved as intended. With the use of the "honest broker" approach the paper provides a conceptual way forward of how a sense of collaboration can be instigated in an engagement process between the policy makers and SMEs, so that the scientific knowledge is translated in an appropriately rational way, which best meets the expectations of the SMEs. Findings: The paper proposes a conceptual model for engaging SMEs that will potentially increase the uptake of flood adaptation measures by SMEs. This could be a useful model with which to kick start a collaborative engagement process that could escalate to wider participation in other areas to improve impact of policy initiatives. Originality/value: The paper lays the conceptual foundation for a new theoretical base in the area, which will encourage more empirical investigations that will potentially enhance the practicality of some of the existing policies. © Emerald Group Publishing Limited.

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This is the final report of the RICS Education Trust funded “Developing Flood Expert Knowledge in Chartered Surveyors – DEFENCES” research project. The UK has endured a number of major flood events in recent years, and the UK Environment Agency (2009a) identified that about 5.2million properties in England, amounting to one in six, are at risk of flooding. The impacts of flooding include direct and indirect impacts and can be particularly devastating for small and medium-sized enterprises (SMEs) who are generally more vulnerable to such events than larger business organisations. Recent flood events have established how costly flooding can be to the SME sector (Pitt, 2008, ABI, 2010), which has given greater impetus to the need to improve the resilience of at-risk SMEs. A lack of professional advice on flood protection and adaptation measures represents a potential barrier to the uptake of such interventions by SMEs. A recent Royal Institution of Chartered Surveyors (RICS) survey, as quoted in Defra (2008) notes that, although a majority of chartered surveyors would like to work in this area of practice (flood risk assessment and adaptation), they are conscious of gaps in their competency, knowledge and understanding. The research project sought to contextualise this broader issue and investigate how chartered surveyors can bridge the gap in providing professional flood advice to SMEs. Further, a shift in the UK government policy on flood risk management is evident, where at-risk communities are urged to adapt to flooding. This places greater emphasis on property-level flood adaptation, providing further impetus for Chartered Surveyors to be involved. Findings of the research will be of interest to the RICS, the RICS Flood steering Group, practicing surveyors generally, SMEs, business support and policy making organisations.

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Single phase solutions containing three components have been observed to exhibit foaminess near a single to two liquid phase boundary. It was seen, in a sintered plate column under mass transfer conditions, that distillation systems where the liquid appeared as one phase in one part of a column and two phases in another part, exhibited foaminess when the liquid concentration was near the one phase to two phase boundary. Various ternary systems have been studied in a 50 plate. 30mm i.d. Oldershaw column and it was observed that severe foaming occurred in the middle section of the column near the one liquid phase to two liquid phase boundary and no foaming occurred at the end of the column where liquid was either one phase or two phase. This is known as Ross type foam. Mass transfer experiments with Ross type ternary systems have been carried out in a perspex simulator with small and large hole diameter trays. It was observed that by removal of the more volatile component, Ross type foam did not build up on the tray. Severe entrainment of liquid was observed in all cases leading to a 'dry' tray, even with a low free area small diameter hole tray which was expected to produce a bubbly mixture. Entrainment was more severe for high gas superficial velocities and large hole diameters. This behaviour is quite different from the build up of foam observed when one liquid phase/two liquid phase Ross systems were contacted with air above a small sintered disc or with vapour in an Oldershaw distillation column. This observation explains why distillation columns processing mixtures which change from one liquid phase to two liquid phases (or vice versa) must be severely derated to avoid flooding. Single liquid phase holdups at the spray to bubbly transition were measured using a perspex simulator similar to that of Porter & Wong (17). i.e. with no liquid cross flow. A light transmission technique was used to measure the transition from spray regime to bubbly regime. The effect of tray thickness and the ratio of hole diameter to tray thickness on the transition was evaluated using trays of the same hole diameter and free area but having thickness of 2.38 mm, 4 mm, and 6.35 mm. The liquid holdup at the transition was less with the thin metal trays. This result may be interpreted by the theory of Lockett (101), which predicts the transition liquid holdup in terms of the angle of the gas iet leaving the holes in the sieve plate. All the existing correlations have been compared and none were found to be satisfactory and these correlations have been modified in view of the experimental results obtained. A new correlation has been proposed which takes into account the effect of the hole diameter to tray thickness ratio on the transition and good agreement was obtained between the experimental results and the correlated values of the liquid holdup at the transition. Results have been obtained for two immiscible liquids [kerosene and water] on trays to determine whether foaming can be eliminated by operating in the spray regime. Kerosene was added to a fixed volume of water or water was added to a fixed volume of kerosene. In both cases, there was a transition from spray to bubbly. In the water fixed system. the liquid holdup at the transition was slightly less than the pure kerosene system. Whilst for the kerosene fixed system, the transition occurred at much lower liquid holdups. Trends In the results were similar to those for single liquid phase. New correlations have been proposed for the two cases. It has been found that Ross type foams, observed in a sintered plate column and in the Oldershaw column can be eliminated by either carrying out the separation in a packed column or by the addition of defoaming additives.

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The literature relating to sieve plate liquid extraction columns and relevant hydrodynamic phenomena have been surveyed. Mass transfer characteristics during drop formation, rise and coalescence, and related models were also reviewed. Important design parameters i.e. flooding, dispersed phase hold-up, drop size distribution, mean drop size, coalescence/flocculation zone height beneath a plate and jetting phenomena were investigated under non-mass transfer and mass transfer conditions in a 0.45m diameter, 2.3m high sieve plate column. This column had provision for four different plate designs, and variable plate spacing and downcomer heights, and the system used was Clairsol `350' (dispersed) - acetone - deionised water (continuous) with either direction of mass transfer. Drop size distributions were best described by the functions proposed by Gal-or, and then Mugele-Evans. Using data from this study and the literature, correlations were developed for dispersed phase hold-up, mean drop size in the preferred jetting regime and in the non-jetting regime, and coalescence zone height. A method to calculate the theoretical overall mass transfer coefficient allowing for the range of drop sizes encountered in the column gave the best fit to experimental data. This applied the drop size distribution diagram to estimate the volume percentage of stagnant, circulating and oscillating drops in the drop population. The overall coefficient Kcal was then calculated as the fractional sum of the predicted individual single drop coefficients and their proportion in the drop population. In a comparison between the experimental and calculated overall mass transfer coefficients for cases in which all the drops were in the oscillating regime (i.e. 6.35mm hole size plate), and for transfer from the dispersed(d) to continuous(c) phase, the film coefficient kd predicted from the Rose-Kintner correlation together with kc from that of Garner-Tayeban gave the best representation. Droplets from the 3.175mm hole size plate, were of a size to be mainly circulating and oscillating; a combination of kd from the Kronig-Brink (circulating) and Rose-Kintner (oscillating) correlations with the respective kc gave the best agreement. The optimum operating conditions for the SPC were identified and a procedure proposed for design from basic single drop data.

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An apparatus was designed and constructed which enabled material to be melted and heated to a maximum temperature of 1000C and then flooded with a pre-heated liquid. A series of experiments to investigate the thermal interaction between molten metals (aluminium, lead and tin) and sub-cooled water were conducted. The cooling rates of the molten materials under conditions of flooding were measured with a high speed-thermocouple and recorded with a transient recorder. A simplified model for calculating heat fluxes and metal surface temperatures was developed and used. Experimental results yielded boiling heat transfer in the transition film and stable film regions of the classic boiling curve. Maximum and minimum heat fluxes were observed at nucleate boiling crisis and the Leidenfrost point respectively. Results indicate that heat transfer from molten metals to sub-cooled water is a function of temperature and coolant depth and not a direct function of the physical properties of the metals. Heat transfer in the unstable transition film boiling region suggests that boiling dynamics in this region where a stationary molten metal is under pool boiling conditions at atmospheric pressure would not initiate a fuel-coolant interaction. Low heat fluxes around the Leidenfrost point would provide efficient fuel-coolant decoupling by a stable vapour blanket to enable coarse mixing of the fuel and coolant to occur without appreciable loss of thermal energy from the fuel. The research was conducted by Gareph Boxley and was submitted for the degree of PhD at the University of Aston in Birmingham in 1980.

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This research investigates the contribution that Geographic Information Systems (GIS) can make to the land suitability process used to determine the effects of a climate change scenario. The research is intended to redress the severe under representation of Developing countries within the literature examining the impacts of climatic change upon crop productivity. The methodology adopts some of the Intergovernmental Panel on Climate Change (IPCC) estimates for regional climate variations, based upon General Circulation Model predictions (GCMs) and applies them to a baseline climate for Bangladesh. Utilising the United Nations Food & Agricultural Organisation's Agro-ecological Zones land suitability methodology and crop yield model, the effects of the scenario upon agricultural productivity on 14 crops are determined. A Geographic Information System (IDRISI) is adopted in order to facilitate the methodology, in conjunction with a specially designed spreadsheet, used to determine the yield and suitability rating for each crop. A simple optimisation routine using the GIS is incorporated to provide an indication of the 'maximum theoretical' yield available to the country, should the most calorifically significant crops be cultivated on each land unit both before and after the climate change scenario. This routine will provide an estimate of the theoretical population supporting capacity of the country, both now and in the future, to assist with planning strategies and research. The research evaluates the utility of this alternative GIS based methodology for the land evaluation process and determines the relative changes in crop yields that may result from changes in temperature, photosynthesis and flooding hazard frequency. In summary, the combination of a GIS and a spreadsheet was successful, the yield prediction model indicates that the application of the climate change scenario will have a deleterious effect upon the yields of the study crops. Any yield reductions will have severe implications for agricultural practices. The optimisation routine suggests that the 'theoretical maximum' population supporting capacity is well in excess of current and future population figures. If this agricultural potential could be realised however, it may provide some amelioration from the effects of climate change.

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Previous work has indicated the presence of collapsing and structured soils in the surface layers underlying Sana's, the capital of Yemen Republic. This study set out initially to define and, ultimately, to alleviate the problem by investigating the deformation behaviour of these soils through both field and laboratory programmes. The field programme was carried out in Sana'a while the laboratory work consisted of two parts, an initial phase at Sana's University carried out in parallel with the field programme on natural and treated soils and the major phase at Aston University carried out on natural, destructured and selected treated soils. The initial phase of the laboratory programme included classification, permeability, and single (collapsing) and double oedometer tests while the major phase, at Aston, was extended to also include extensive single and double oedometer tests, Scanning Electron Microscopy and Energy Dispersive Spectrum analysis. The mechanical tests were carried out on natural and destructed samples at both the in situ and soaked moisture conditions. The engineering characteristics of the natural intact, field-treated and laboratory destructured soils are reported, including their collapsing potentials which show them to be weakly bonded with nil to severe collapsing susceptibility. Flooding had no beneficial effect, with limited to moderate improvement being achieved by preloading and roller compaction, while major benefits were achieved from deep compaction. From these results a comparison between the soil response to the different treatments and general field remarks were presented. Laboratory destructuring reduced the stiffness of the soils while their compressibility was increasing. Their collapsing and destructuring mechanisms have been examined by studying the changes in structure accompanying these phenomena. Based on the test results for the intact and the laboratory destructured soils, a simplified framework has been developed to represent the collapsing and deformation behaviour at both the partially saturated and soaked states, and comments are given on its general applicability and limitations. It has been used to evaluate all the locations subjected to field treatment. It provided satisfactory results for the deformation behaviour of the soils destructed by field treatment. Finally attention is drawn to the design considerations together with the recommendations for the selection of potential improvement techniques to be used for foundation construction on the particular soils of the Sana's region.

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The Triassic rocks of Central England consist of three major stratigraphic units: Sherwood Sandstone Group, Mercia Mudstone Group, and Penarth Group. The lower part of the Sherwood Sandstone Group represented by the Kidderminster, Cannock Chase, and Polesworth Formations represents pebbly braided river deposits carried by a major fluvial system flowing to the North-Northwest. The upper part of the Sherwood Sandstone Group includes the Wildmoor and Bromsgrove Sandstone Formations, the deposits of a sandy alluvial system. The Mercia Mudstone Group represents quiet-water deposits of marginal palya type which were subjected to occasional marine flooding. The overlying Penarth Group represent shallow marine and lagoonal environment associated with the Rhaetian marine transgression. The mineralogy of the Triassic sandstones indicates that the main source was from medium to low rank metamorphic rocks with additional supplies from igneous and metamorphic rocks. The study of size-composition trends shows that the climate was semiarid in early Triassic time and became more humid later. The Triassic sandstones show a variety of diagenetic features typical of continental red beds; these include: 1. the dissolution of unstable ferromagnesian silicates, 2. the replacement of detrital grains by clay, 3. the pseudomorphism of biotite by haematite, and 4. the formation of a suite of authigenic minerals including quartz, illite, mixed-layer illite-montmorillonite, kaolinite, k-feldspar, haematite, titanium oxide and later carbonate cement. Palaeomagnetic studies of selected samples show that the magnetization is muticomponent with the various components being carried by different textural phases of haematite.

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A 10 cm diameter four-stage Scheibel column with dispersed phase wetted packing sections has been constructed to study the hydrodynamics and mass transfer using the system toluene-acetone-water. The literature pertaining to the above extractor has been examined and the important phenomena such as droplet break-up and coalescence, mass transfer and backmixing have been reviewed. A critical analysis of the backmixing or axial mixing models and the corresponding techniques for parameter estimation was applied and an optimization technique based on Marquardt's algorithm was implemented. A single phase sampling technique was developed to estimate the acetone concentration profile in both phases along the column. Column flooding characteristics were investigated under various operating conditions and it was found that, when the impellers were located at about DI/5cm from the upper surface of the pads, the limiting flow rates increased with impeller speed. This unusual behaviour was explained in terms of the pumping effect created by the turbine impellers. Correlations were developed to predict Sauter mean drop diameters. A five-cell with backflow model was used to estimate the column performance (stage efficiency) and phases non-ideality (backflow parameters). Overall mass transfer coefficients were computed using the above model and compared with those calculated using the correlations based on single drop mechanism.

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This dissertation studies the caching of queries and how to cache in an efficient way, so that retrieving previously accessed data does not need any intermediary nodes between the data-source peer and the querying peer in super-peer P2P network. A precise algorithm was devised that demonstrated how queries can be deconstructed to provide greater flexibility for reusing their constituent elements. It showed how subsequent queries can make use of more than one previous query and any part of those queries to reconstruct direct data communication with one or more source peers that have supplied data previously. In effect, a new query can search and exploit the entire cached list of queries to construct the list of the data locations it requires that might match any locations previously accessed. The new method increases the likelihood of repeat queries being able to reuse earlier queries and provides a viable way of by-passing shared data indexes in structured networks. It could also increase the efficiency of unstructured networks by reducing traffic and the propensity for network flooding. In addition, performance evaluation for predicting query routing performance by using a UML sequence diagram is introduced. This new method of performance evaluation provides designers with information about when it is most beneficial to use caching and how the peer connections can optimize its exploitation.

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Enhancing the resilience of local communities to weather extremes has gained significant interest over the years, amidst the increased intensity and frequency of such events. The fact that such weather extremes are forecast to further increase in number and severity in future has added extra weight to the importance of the issue. As a local community consists of a number of community groups such as households, businesses and policy makers, the actions of different community groups in combination will determine the resilience of the community as a whole. An important role has to be played by Small and Medium-sized Enterprises (SMEs); which is an integral segment of a local community in the UK, in this regard. While it is recognised that they are vital to the economy of a country and determines the prosperity of communities, they are increasingly vulnerable to effects of extreme weather. This paper discusses some of the exploratory studies conducted in the UK on SMEs and their ability to cope with extreme weather events, specifically flooding. Although a reasonable level of awareness of the risk was observed among the SMEs, this has not always resulted in increased preparedness even if they are located in areas at risk of flooding. The attitude and the motivation to change differed widely between SMEs. The paper presents schemas by which the SMEs can identify their vulnerability better so that they can be populated among a community of SMEs, which can be taken forward to inform policy making in this area. Therefore the main contribution the paper makes to the body of knowledge in the area is a novel way to communicate to SMEs on improving resilience against extreme weather, which will inform some of the policy making initiatives in the UK.

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Despite Government investment in flood defence schemes, many properties remain at high risk of flooding. A substantial portion of these properties are business establishments. Flooding can create serious consequences for businesses, including damage to property and stocks, being out of business for a considerable period and ultimately business failure. Recent flood events such as those in 2007 and 2009 that affected many parts of the UK have helped to establish the true costs of flooding to businesses. This greater understanding of the risks to businesses has heightened the need for business owners to adapt their businesses to the threat of future flooding. Government policy has now shifted away from investment in engineered flood defences, towards encouraging the uptake of property level flood resistance and resilience measures by businesses. However, implementing such adaptation strategies remains a challenge due a range of reasons. A review of the current state of property level flood risk adaptation of UK businesses is presented, drawing from extant literature. Barriers that may hinder the uptake of property level adaptation by businesses are revealed and drivers that may enhance uptake and effectively overcome these barriers are also discussed. It is concluded that the professions from the construction sector have the potential to contribute towards the adaptation of business properties and thereby the flood resilience of businesses at risk of flooding.

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Purpose – The UK has experienced a number of flood events in recent years, and the intensity and frequency of such events are forecast to further increase in future due to changing climatic conditions. Accordingly, enhancing the resilience of small and medium-sized enterprises (SMEs) – which form an important segment in a society – to flood risk, has emerged as an important issue. However, SMEs often tend to underestimate the risk of flooding which tends to have a low priority in their business agenda. The purpose of this paper is to undertake an investigation of adaptation to the risk of flooding considering community-level measures, individual-level property protection, and business continuity and resilience measures. Design/methodology/approach – A total of four short case studies were conducted among SMEs to identify their response to flood risk, and what measures have been undertaken to manage the risk of flooding. Findings – It was observed that SMEs have implemented different property-level protection measures and generic business continuity/risk management measures, based on their requirements, to achieve a desired level of protection. Practical implications – SMEs are likely to positively respond to property-level adaptation following a post-flood situation. It is important that information such as costs/benefits of such measures and different options available are made accessible to SMEs affected by a flood event. Social implications – Implementation of property-level adaptation measures will contribute towards the long term adaptation of the existing building stock to changing climatic conditions. Originality/value – The paper contributes towards policy making on flood risk adaptation and SME decision making, and informs policy makers and practitioners.

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Flooding can have a devastating impact on businesses, especially on small- and medium-sized enterprises (SMEs) who may be unprepared and vulnerable to the range of both direct and indirect impacts. SMEs may tend to focus on the direct tangible impacts of flooding, limiting their ability to realise the true costs of flooding. Greater understanding of the impacts of flooding is likely to contribute towards increased uptake of flood protection measures by SMEs, particularly during post-flood property reinstatement. This study sought to investigate the full range of impacts experienced by SMEs located in Cockermouth following the floods of 2009. The findings of a questionnaire survey of SMEs revealed that businesses not directly affected by the flooding experienced a range of impacts and that short-term impacts were given a higher significance. A strong correlation was observed between direct, physical flood impacts and post-flood costs of insurance. Significant increases in the costs of property insurance and excesses were noted, meaning that SMEs will be exposed to increased losses in the event of a future flood event. The findings from the research will enable policy makers and professional bodies to make informed decisions to improve the status of advice given to SMEs. The study also adds weight to the case for SMEs to consider investing in property-level flood risk adaptation measures, especially during the post flood reinstatement process. © 2012 Blackwell Publishing Ltd and The Chartered Institution of Water and Environmental Management (CIWEM).

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Worldwide floods have become one of the costliest weather-related hazards, causing large-scale human, economic, and environmental damage during the recent past. Recent years have seen a large number of such flood events around the globe, with Europe and the United Kingdom being no exception. Currently, about one in six properties in England is at risk of flooding (EA, 2009), and the risk is expected to further increase in the future (Evans et al., 2004). Although public spending on community-level flood protection has increased and some properties are protected by such protection schemes, many properties at risk of flooding may still be left without adequate protection. As far as businesses are concerned, this has led to an increased need for implementing strategies for property-level flood protection and business continuity, in order to improve their capacity to survive a flood hazard. Small and medium-sized enterprises (SMEs) constitute a significant portion of the UK business community. In the United Kingdom, more than 99% of private sector enterprises fall within the category of SMEs (BERR, 2008). They account for more than half of employment creation (59%) and turnover generation (52%) (BERR, 2008), and are thus considered the backbone of the UK economy. However, they are often affected disproportionately by natural hazards when compared with their larger counterparts (Tierney and Dahlhamer, 1996; Webb, Tierney, and Dahlhamer, 2000; Alesch et al., 2001) due to their increased vulnerability. Previous research reveals that small businesses are not adequately prepared to cope with the risk of natural hazards and to recover following such events (Tierney and Dahlhamer, 1996; Alesch et al., 2001; Yoshida and Deyle, 2005; Crichton, 2006; Dlugolecki, 2008). For instance, 90% of small businesses do not have adequate insurance coverage for their property (AXA Insurance UK, 2008) and only about 30% have a business continuity plan (Woodman, 2008). Not being adequately protected by community-level flood protection measures as well as property- and business-level protection measures threatens the survival of SMEs, especially those located in flood risk areas. This chapter discusses the potential effects of flood hazards on SMEs and the coping strategies that the SMEs can undertake to ensure the continuity of their business activities amid flood events. It contextualizes this discussion within a survey conducted under the Engineering and Physical Sciences Research Council (EPSRC) funded research project entitled “Community Resilience to Extreme Weather — CREW”.