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O'Sullivan, J. J.
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O'Sullivan, J. J.
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O'Sullivan, J. J.
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Now showing 1 - 10 of 32
- PublicationModelling Quantified Microbial Source Specific Pollution from Domestic Wastewater Treatment Systems during High Flows(2016-11-15)
; ; ; ; ; ; ; The ability to model the transport of source specific faecal bacteria contamination in river networks can equip water resource managers with information of the different pathogens that are present. Such information can be particularly useful in catchment management plans for rivers from which potable water is extracted or where these rivers discharge to coastal zones where bathing or aquaculture is prominent and where the evaluation of human health risks is of primary importance. This paper presents an application and performance assessment of the commercially available MIKE11 Hydrodynamic model for evaluating the fate of faecal bacteria of human origin, Human Gene Marker HF183f, from Domestic Wastewater Treatment Systems within the Dargle catchment. The Dargle is a spate river and the upper catchment is characterised by steep slopes that incorporates peat bogs and land used for forestry and agricultural purposes. Residential dwellings within the area are predominantly single detached units that rely on septic tanks for wastewater treatment. In the context of faecal bacteria of human origin, malfunctioning systems are of concern, particularly in terms of surface ponding, leakage to groundwater and direct discharge to surface waters. The MIKE11 model was calibrated in a two stages process. Firstly, the model was calibrated for prediction of discharge and microbial water quality parameters, namely E. coli and Intestinal Enterococci (IE), using data from a real-time sensor network within the catchment that comprised rain gauges, weather stations and water level recorders, data from which was used to determine flow records from stage-discharge ratings. E. coli and IE concentrations were determined from high resolution sampling during storm events. Following this, water quality samples taken during storm event sampling were used to identify and quantify the human gene marker HF183f using quantitative polymer chain reaction (qPCR) techniques. Results from the qPCR analysis were used to further calibrate the model at sub-catchment level for the transport of microbial bacteria derived from human origins. Using non-compliance statistics from the EPA National Inspection Plan, domestic sources have been calculated based on the percentage number of malfunctioning septic tank units and average daily faecal gene marker concentrations per household. The study highlights issues with how the fate of the human gene marker is modelled using MIKE11, particularly in terms of advection-dispersion inputs and the requirement to associate microbial concentrations with total runoff when modelling surface and groundwater pathways.99 - PublicationNon-Intrusive Bridge Scour Analysis Technique using Laboratory Test Apparatus(2012-09-07)
; ; 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.157 - PublicationExtreme wave overtopping at ecologically modified sea defences(Copernicus, 2020-05-08)
; ; ; Damage to coastal structures and surrounding properties from wave overtopping in extreme events is expected to be exacerbated in future years as global sea levels continue to rise and the frequency of extreme meteorological events and storm surges increases. Approaches for protecting our coastal areas have traditionally relied on the development and ongoing maintenance of ‘hard’ defences. However, the longer-term sustainability of coastal flood management that is underpinned by such defences is increasingly being questioned both in terms of dealing with climate change and in the environmental/ ecological consequences and associated losses of biodiversity that comes with these structural defence lines in coastal areas.78 - PublicationTRUSS Training in Reducing Uncertainty in Structural Safety: D2.5 Final Report: WP2 - Dissemination and Outreach(European Commission, 2019-02-28)
; ; ; ; ; ; ; ; ; ; ; ; 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.361 - PublicationSpatial Bayesian hierarchical modelling of extreme sea states(Elsevier, 2016-11)
; ; ; ; A Bayesian hierarchical framework is used to model extreme sea states, incorporating a latent spatial process to more effectively capture the spatial variation of the extremes. The model is applied to a 34-year hindcast of significant wave height off the west coast of Ireland. The generalised Pareto distribution is fitted to declustered peaks over a threshold given by the 99.8th percentile of the data. Return levels of significant wave height are computed and compared against those from a model based on the commonly-used maximum likelihood inference method. The Bayesian spatial model produces smoother maps of return levels. Furthermore, this approach greatly reduces the uncertainty in the estimates, thus providing information on extremes which is more useful for practical applications.325Scopus© Citations 9 - PublicationStudying the maximum instantaneous non-synchronous generation in an Island system-frequency stability challenges in Ireland(IEEE, 2014-11)
; ; ; ; ; Synchronous island power systems, such as the combined Ireland and Northern Ireland power system, are facing increasing penetrations of renewable generation. As part of a wider suite of studies, performed in conjunction with the transmission system operators (TSOs) of the All-Island system (AIS), the frequency stability challenges at high and ultra-high wind penetrations were examined. The impact of both largest infeed loss and network fault induced wind turbine active power dips was examined: the latter contingency potentially representing a fundamental change in frequency stability risk. A system non-synchronous penetration (SNSP) ratio was defined to help identify system operational limits. A wide range of system conditions were studied, with results showing that measures such as altering ROCOF protection and enabling emulated inertia measures were most effective in reducing the frequency stability risk of a future Ireland system. © 2014 IEEE.2095Scopus© Citations 252 - PublicationA high-resolution, multi-model analysis of Irish temperatures for the mid-21st centuryThere is a paucity of dynamically downscaled climate model output at a high resolution over Ireland, of temperature projections for the mid-21st century. This study aims to address this shortcoming. A preliminary investigation of global climate model (GCM) data and high-resolution regional climate model (RCM) data shows that the latter exhibits greater variability over Ireland by reducing the dominance of the surrounding seas on the climate signal. This motivates the subsequent dynamical downscaling and analysis of the temperature output from three high-resolution (4–7 km grid size) RCMs over Ireland. The three RCMs, driven by four GCMs from CMIP3 and CMIP5, were run under different Special Report on Emissions Scenarios (SRES) and representative concentration pathway (RCP) future scenarios. Projections of mean and extreme temperature changes are considered for the mid-century (2041–2060) and assessed relative to the control period of 1981–2000. Analysis of the RCM data shows that annual mean temperatures are projected to rise between 0.4 and 1.8 °C above control levels by mid-century. On a seasonal basis, results differ by forcing scenario. Future summers have the largest projected warming under RCP 8.5, where the greatest warming is seen in the southeast of Ireland. The remaining two high emission scenarios (SRESs A1B and A2) project future winters to have the greatest warming, with almost uniform increases of 1.5–2 °C across the island. Changes in the bidecadal 5th and 95th percentile values of daily minimum and maximum temperatures, respectively, are also analysed. The greatest change in daily minimum temperature is projected for future winters (indicating fewer cold nights and frost days), a pattern that is consistent across all scenarios/forcings. An investigation into the distribution of temperature under RCP 8.5 shows a strong summer increase compounded by increased variability, and a winter increase compounded by an increase in skewness.
573Scopus© Citations 11 - PublicationAcademic Advising in Civil Engineering: design and evaluation of a hybrid model(MDPI, 2022-05-06)
; ; ; ; ; ; ; ; ; A project to formalise and expand Academic Advising has been implemented at the UCD Civil Engineering School. The goals of this project were twofold: on the one hand, it aimed at training faculty members in Academic Advising roles and providing them with the necessary resources. On the other hand, the project sought to expand student interaction, in particular by engaging students informally in order to build a rapport between them and the academic advisors that we expect will bring long term benefits. The resulting model combines elements of both the prescriptive, e.g., formal training, informative talks on key topics, and developmental approaches, e.g., coffee mornings for students and faculty members. The evaluation of the project was carried out through questionnaires and focus groups. It highlighted very positive feedback from the students, who find these new lines of communication with the academic staff to be useful and productive.106Scopus© Citations 2 - PublicationSediment transport formulae for compound channel flows(Institution of Civil Engineers, 2006-09-01)
; ; ; ; Nine sediment transport formulae were reviewed and applied to both inbank and overbank flows in straight and meandering compound channels. The predictive capabilities of the formulae were evaluated using experimental data obtained from the large-scale UK Flood Channel Facility and the small-scale Ulster Channel. The Yang formula (1979) was found to give the best prediction for sediment discharge, performing well for both straight and meandering channels. The Schoklitch (1962) and Yang and Lim (2003) formulae also gave very good predictions for most of the data sets studied. The Ackers and White formula (1973) gave very good prediction for the large-scale facility but overpredicted the sediment discharge for the small-scale channel. The Karim and Kennedy (1981) formula could also be a good sediment discharge predictor, for the studied flow conditions, but the coefficient of proportionality used in the formula needs to be calibrated.987Scopus© Citations 4 - PublicationThe CRITHINKEDU European Course on critical thinking education for university teachers : from conception to delivery(UTAD, 2018-05)
; ; ; ; ; ; 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).430