Now showing 1 - 10 of 35
  • Publication
    Flow resistance of emergent vegetation
    Conventional resistance equations (such as those of Manning, Chézy and Darcy-Weisbach) are inappropriate for flow through emergent vegetation, where resistance is exerted primarily by stem drag throughout the flow depth rather than by shear stress at the bed. An alternative equation form is suggested, in which the resistance coefficient is related to measurable vegetation characteristics and can incorporate bed roughness when this is significant. Equation performance is confirmed by comparison of predicted and measured stage-discharge relationships for flow through artificial cylindrical stems, and by comparison of calibrated and measured drag coefficient values for natural vegetation.
  • Publication
    TRUSS Training in Reducing Uncertainty in Structural Safety: D2.5 Final Report: WP2 - Dissemination and Outreach
    This report describes the outputs of work package WP2 (Dissemination and Outreach) from 1 st January 2015 to 31st December 2018. Dissemination by TRUSS is keenly aware of the importance of not only producing and presenting research outputs for the scientific community and key stakeholders (i.e., via conferences, workshops, publications and reports), but also engaging the general public in line with the Innovation Union objectives. TRUSS mainly deals with the challenges faced at the design, assessment and management stages of large scale structures. Outreach activities, blogs and social media and other communications by TRUSS, bring awareness to the public on the importance of this research on infrastructure to support a community, region or country, and also motivate School and University students to pursue a research career. These activities make citizens aware of: • Infrastructure aging and failing, with funding that has been insufficient to repair and replace it; • The important role of the Marie Skłodowksa-Curie Actions in forming 21st century engineers that will have the skills to face the formidable challenge of modernizing the fundamental infrastructure that support civilization.
  • Publication
    A European collection of the Critical Thinking skills and dispositions needed in different professional fields for the 21st century
    Within the scope of the project CRITHINKEDU, this report provides an overall analysis of the understanding of Critical Thinking (CT) by employers and establishes similarities and differences in its expression, need and practical application at the workplace. Adopting a qualitative research methodology, 32 focus groups were conducted enrolling 189 professionals from 9 European countries. The focus groups comprised graduates from 4 different professional fields, namely Biomedical Sciences, STEM (Sciences, Technology, Engineering and Mathematics), Social Sciences and the Humanities. Based on the Facione’ theoretical framework (Facione, 1990), key findings are in line with previous studies (Jones, 2009; Jones, 2010; Grace & Orrock, 2015; Sin, Jones & Wang, 2015), suggesting that CT is widely understood and interpreted as a set of interdependent skills and dispositions that are unquestionably needed in recent graduates. This is due to today’s labour market and societal demands, although with slight differences in their practical application that tend to vary across professional fields.
  • Publication
    Assessment of the Extent and Impact of Barriers on Freshwater Hydromorphology and Connectivity in Ireland (Reconnect)
    The Reconnect project advanced knowledge on the impact of low-head barriers on connectivity in Irish rivers in terms of sediment dynamics and ecology (fish, macroinvertebrates and macrophytes) through studies undertaken from 2016 to 2020 in four core study areas on the Duag, Dalligan and Burren rivers and Browns Beck Brook and at 35 other locations across 12 river/stream systems. The project also developed a methodology for prioritising barriers for modification or removal to improve hydromorphology and connectivity.
  • Publication
    The CRITHINKEDU European Course on critical thinking education for university teachers : from conception to delivery
    Within the scope of the CRITHINKEDU project1, this intellectual output (Output 3) reports the experience of conceiving and delivering a European training course on Critical Thinking (CT) education for university teachers. It draws on the proposal of the “European inventory of critical thinking skills and dispositions for the 21st century” and the “Preliminary guidelines for quality in critical thinking education” - both presented in the two previous intellectual outputs of the project (Dominguez, 2018a, 2018b). This report is targeted to each leading partner institution or to any Higher Education (HE) institution which desire to later replicate this training course at the local level, to faculty staff interested in the implementation of CT teaching practices and learning activities in their classroom. Deployments within the CRITHINKEDU project will be carried-out as part of the fourth and following intellectual output (Output 4).
  • Publication
    A European review on Critical Thinking educational practices in Higher Education Institutions
    Within the scope of CRITHINKEDU project, this report is directed to university teachers, pedagogical support teams and institutional leaders, providing an overall understanding on how European Higher Education Institutions (EHEI) foster Critical Thinking (CT), taking into account both the current educational intervention studies reported in the literature and teachers' educational practices. Adopting a mixed method research design, 46 papers from the literature were reviewed and 53 interviews with university teachers from 9 European countries were carried out. The analysis comprised both studies and teachers' interviews from 4 different professional fields, namely Biomedical Sciences, STEM (Sciences, Technology, Engineering and Mathematics), Social Sciences and the Humanities.
  • Publication
    Effectiveness of Eco-retrofits in Reducing Wave Overtopping on Seawalls
    (Coastal Engineering Research Council, 2020-12-28) ; ; ;
    Terms such as 'nature-based', 'living shoreline', 'green infrastructure' and 'ecological engineering' are increasingly being used to reflect biomimicry-based engineering measures in coastal defences. Innovative interventions for nature-based sea defences have included the retrofitting of man-made water filled depressions or 'vertipools' to existing seawalls (Hall et al., 2019; Naylor et al., 2017) and the addition of artificial drill-cored rock pools to intertidal breakwaters (Evans et al., 2016). Through their capacity to retain water, such measures serve to enhance biodiversity in the built environment (Browne and Chapman, 2014). Evans et al. (2016) for example, experimentally demonstrated that the introduction of artificial rock pools to an intertidal granite breakwater enhanced the levels of species richness compared to those observed on plain surfaces of the breakwater. Notwithstanding these biological benefits, the impetus for incorporation of ecologically friendly measures to existing defences remains low (Salauddin et al., 2020a). This situation could potentially change should it be shown that the addition of 'green' measures to sea defences could enhance wave attenuation and reduce wave overtopping as well as wave pressures on the coastal defence structures. This paper describes small-scale physical modelling investigations of seawalls and explores reductions in wave overtopping that could be realised by retrofitting sea defences with 'green' features (such as 'vertipools'). Surface protrusions of varying scale and density are used in the physical modelling to mimic 'green' features and the results from measurements of overtopping are benchmarked to reference conditions determined from tests on a plain seawall.
  • Publication
    Distribution of Individual Wave Overtopping Volumes on a Sloping Structure with a Permeable Foreshore
    (Coastal Engineering Research Council, 2020-12-31) ; ; ; ;
    Maximum wave overtopping volumes on sea defences are an indicator for identifying risks to people and properties from wave hazards. The probability distribution of individual overtopping volumes can generally be described by a two-parameter Weibull distribution function (shape and scale parameters). Therefore, the reliable prediction of maximum individual wave overtopping volumes at coastal structures relies on an accurate estimation of the shape factor in the Weibull distribution. This study contributes to an improved understanding of the distribution of individual wave overtopping volumes at sloping structures by analysing the wave-by-wave overtopping volumes obtained from physical model experiments on a 1V:2H sloped impermeable structure with a permeable shingle foreshore of slope 1V:20H. Measurements of the permeable shingle foreshore were benchmarked against those from an identical experimental set-up with a smooth impermeable foreshore (1V:20H) of the same geometry. Results from both experimental set-ups were compared to commonly used empirical formulations, underpinned by the assumption that an impermeable foreshore exists in front of the sea structure. The effect on the shape factor in the Weibull distribution of incident wave steepness, relative crest freeboard, probability of overtopping waves and discharge are examined to determine the variation of individual overtopping volumes with respect to these key parameters. A key finding from the study is that no major differences in Weibull distribution shape parameter were observed for the tested impermeable and permeable sloped foreshores. Existing empirical formulae were also shown to predict reasonably well the Weibull distribution shape parameter, b, at sloping structures with both impermeable and permeable slopes.
  • Publication
    Non-Intrusive Bridge Scour Analysis Technique using Laboratory Test Apparatus
    Larger and more frequent flood flows expose foundation soils to stronger erosive forces, increasing the likelihood that scour of piers (and abutments) will compromise the structural integrity of some bridges. The development of low-cost, low maintenance, non-destructive methods of bridge scour analysis is therefore becoming ever more important in light of the current economic climate. The use of embedded sensors that measure vibration responses of a structure, due to train loading, may offer potential to track changes in the foundation soil stiffness matrix caused by scour and may inform engineers in implementing appropriate protection schemes. This paper presents a laboratory investigation in which the dynamic response of a scaled pier, installed in a bed of sand and instrumented with an accelerometer, is recorded for a constant and repeatable excitation. Sand stiffness properties were manually altered by increasing the scour depth in progressive experiments. For each experiment, a vibration response was recorded and this was converted to a frequency response using a fast Fourier transform (FFT). Differences between the dynamic signatures of the pier for the different scour conditions investigated were analysed to explore whether this type of non-destructive testing could provide a viable method of detecting scour before the structural integrity of the bridge reaches a critical stage. Results indicate that significantly different frequency responses are recorded for decreasing elevations of bed material around the model pier, indicating that the method may provide the basis for a simple and effective means of monitoring scour around bridge piers.
  • Publication
    Bayesian spatial modelling of climate extremes
    (University College Dublin. School of Biology and Environmental Science, 2020)
    This thesis is primarily concerned with determining effective and efficient methods to model spatial datasets of climate extremes. Climate extremes impact our technology, our infrastructure, the environment, and humans ourselves. Faced with the uncertainties and challenges of human-induced climate change, it is now more important than ever to understand the behaviour of climate extremes. Existing observations of extreme events are, by definition, rare, which makes any analysis and interpretation of this data more challenging than other analyses. Extrapolation beyond the observed extremes is necessary in order to plan for events worse than those already observed. This extrapolation needs a sound theoretical framework as mitigation and adaptation planning often involves practical and financial risks and implications. The framework applied should incorporate prior information, result in useful predictions of practical benefit, and be adaptable to model datasets across a dense spatial domain. It is these aims and objectives which guided and informed the research undertaken during the course of this thesis. The first study I undertook involved using dynamically downscaled climate model output from CMIP3 and CMIP5. From this, I analysed the temperature changes projected over Ireland for the mid-21st century under different future climate change scenarios. I found that annual mean temperatures were projected to rise by between 0.4C and 1.8C by the mid-century. On a seasonal basis, projected temperature changes differed by forcing scenario. Some scenarios saw future summers with the largest projected warming; others projected future winters to warm the most. An investigation into the projected change in temperature extremes found that in general there was greater projected changes in the number of cold nights and the number of hot days than for mean temperatures. In the next study undertaken, I applied extreme value theory (EVT) in a Bayesian spatial hierarchical framework in order to model extremes of significant wave heights off the west coast of Ireland for the period 1979-2012. I found that the highest extremes of significant wave height were to be expected off the west coast of Ireland roughly between 53N and 54.5N, with 100-year levels close to 17 m. A comparison of the Bayesian spatial model with a simpler maximum likelihood site-specific approach found that the former resulted in smoother surfaces of posterior parameters and return level maps, with less uncertainty while still showing a satisfactory fit to the data. In the final study undertaken, I extended the Bayesian spatial hierarchical framework using a dimension reduction technique called predictive processes. This extension was necessary in order to model a spatially dense dataset of extremes of daily maximum temperature anomalies over Dublin, Ireland, for the period 1981-2010. The results included a posterior median 100-year return level surface for anomalies of maximum temperature ranging from 8C to 10.7C across the domain, with an upperbound of 12.7C. Additional analysis involved placing more recent extremes (2011-2018) from synoptic stations across the domain in the context of the model results. Including this data in the analysis showed an increase in the frequency of extreme anomalies for this period, but not in their severity. The methods presented in this thesis can be readily adapted to any spatially-continuous dataset. One advantage to using a Bayesian framework is the incorporation of prior information, which leads to a reduction in the uncertainty of quantities such as return levels, and thus provides information on extremes which is more useful for practical applications. The main advantage of the predictive processes approach is the ability to fit a spatial model which would otherwise be too computationally expensive to fit, allowing me to achieve results which would not have been possible by fitting the full model to the dense dataset.