Research Publications

 

All titles published by the School are listed in the yearly President's reports classified by type of publication and author and can be downloaded for each academic season from the links in the right hand side menu. 

Full text for some of these titles are available in the Open Access Institutional Repository of UCD Research. The top 10 downloads from the School repository are listed in the right hand side menu and can be accessed by clicking each title. The most recent uploads to the repository can be accessed in the list below. Following this list, an archive of news involving publications by the School is provided.

What are the main sources of nutrient inputs to Ireland's aquatic environment?

What are the main sources of nutrient inputs to Ireland's aquatic environment? Mockler, Eva M.; Deakin, Jenny; Daly, Donal; Bruen, Michael; Archbold, Marie A. Where rivers and lakes are impacted by excess nutrients, we need to understand the sources of those nutrients before mitigation measures can be selected. In these areas, modelling can be used in conjunction with knowledge from local authorities and information gained from investigative assessments to identify significant pressures that contribute excessive nutrients to surface waters. Where surface waters are impacted by excess nutrients, understanding the sources of those nutrients is key to the development of effective, targeted mitigation measures. In Ireland, nutrient emissions are the main reason that surface waters are not achieving the required Good Status, as defined by the Water Framework Directive (WFD). A model has been developed in order to predict the sources of nutrients contributing to these emissions and to assess future pressures and the likely effectiveness of targeted mitigation scenarios. This Source Load Apportionment Model (SLAM) supports catchment managers by providing scientifically robust evidence to back-up decision-making in relation to reducing nutrient pollution. The SLAM is a source-oriented model that calculates the nitrogen and phosphorus exported from each sector (e.g. pasture, forestry, wastewater discharges) that contribute to nutrient loads in a river. Model output is presented as maps and tables showing the proportions of nutrient emissions to water attributed to each sector in each sub-catchment. The EPA has incorporated these model results into the multiple lines of evidence used for the WFD characterisation process for Irish catchments.  International Association of Hydrogeologists (IAH) (Irish Group) Conference, 25-26 April 2017, Tullamore, Offaly, Ireland
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A New Damage Indicator for Drive-by Monitoring using Instantaneous Curvature

A New Damage Indicator for Drive-by Monitoring using Instantaneous Curvature O'Brien, Eugene J.; Martinez, Daniel; Malekjafarian, Abdollah; Pape, Torill Drive-by monitoring has enhanced the possibilities for bridge damage detection, with the potential to deliver a bridge rating in the time it takes an instrumented vehicle to pass overhead. This paper outlines the importance of Instantaneous Curvature (IC) as an indicator of local damage. For the IC calculation, bridge deflections are measured from the vehicle before and after the occurrence of damage, so that a comparison between the two situations can be made. Differences in curvature are clearly visible in numerical simulations, especially at the damage location. A Finite Element model of a simply supported bridge subject to a crossing vehicle is modelled dynamically. In this paper, the Curvature Ratio (CR) is proposed as the damage indicator, defined as the ratio of IC in the current bridge to IC in the corresponding healthy bridge. Road profile and random noise in the simulated measurements are considered to represent realistic conditions. Simulations in MATLAB demonstrate that CR is an effective indicator in most of the analysis cases. Austroads Bridge Conference 2017 (ABC 2017), Pullman Melbourne Albert Park, Melbourne, Australia, 3-6 April 2017
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What have we learned from over two decades of monitoring riverine nutrient inputs to Ireland's marine environment?

What have we learned from over two decades of monitoring riverine nutrient inputs to Ireland's marine environment? O'Boyle, Shane; Quinn, Rebecca; Dunne, Noelle; Mockler, Eva M.; Ní Longphuirt, Sorcha Excessive nutrient loading to the marine environment from different sources and pathways, including rivers, has led to nutrient over-enrichment and the phenomenon of eutrophication in estuaries and coastal waters. The systematic monitoring of riverine nutrient inputs to Ireland's marine environment began in 1990. Over this period there has been a large reduction in nutrient inputs with loads of total phosphorus, total ammonia and total nitrogen decreasing by 71.8% (4,716 tonnes), 77.3% (5,505 tonnes) and 39.0% (59,396 tonnes), respectively. The largest reductions, particularly in total phosphorus and total ammonia, were seen in the main rivers discharging to the Celtic and Irish Sea coasts, with smaller or no reductions in rivers discharging along the western and north-western Atlantic coast. The reductions indicate the success of measures to reduce nutrient loss but also the disproportionate reduction in phosphorus over nitrogen. The ratio between nitrogen and phosphorus loads has increased by 2.5% per year and by as much as 4.1% per year for discharges to the Celtic Sea. As a consequence, the stoichiometric N:P ratio of river inputs to the Celtic Sea has more than doubled. The potential for this disparity to create a nutrient imbalance in downstream estuarine and coastal waters is discussed.
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Linking changes in nutrient load source apportionment to estuarine responses: an Irish perspective

Linking changes in nutrient load source apportionment to estuarine responses: an Irish perspective Ní Longphuirt, Sorcha; Mockler, Eva M.; O'Boyle, Shane; et al. In the Irish environment, anthropogenic pressures have led to widespread nutrient over-enrichment and eutrophication in surface waters. In the past 25 years European Directives have been implemented resulting in significant measures to improve water quality. Multi-decadal monitoring of nutrient inputs from rivers, and response parameters in estuarine and coastal systems, allows for a comparison of the effectiveness of these measures. In this study, trends in nutrient inputs from eighteen river systems and downstream estuarine parameters between 2000 and 2013 are explored. The results are placed in the context of changes in nutrient source load apportionment modelled through a newly developed GIS tool. Measured phosphorus inputs showed a significant reduction from fifteen catchments, with only four rivers showing a concurrent reduction in nitrogen.Significant Parallel improvements in estuarine water quality were evident in eight downstream systems, highlighting the complexity of response mechanisms. Load apportionment illustrated that the effectiveness of measures largely depended on factors such as land use and the proximity of large urban agglomerations to the estuary. The partitioning of nutrient sources could determine the nutrient landscape of the downstream estuary, with possible implications for the ecological health of the system.The results of the study will inform decision makers on the effectiveness of measures to date and the possible response of systems to future controls in the light of targets set out under the Water Framework Directive.
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ESManage Programme: Irish Freshwater Resources and Assessment of Ecosystem Services Provision

ESManage Programme: Irish Freshwater Resources and Assessment of Ecosystem Services Provision Feeley, Hugh B.; Bruen, Michael; Bullock, Craig; Christie, Mike; Kelly, Fiona; Kelly-Quinn, Mary Freshwater is vital for all forms of life and it is a key requirement in almost all human activities. The societal importance of water has been highlighted by the United Nations, with access to clean water and sanitation regarded as a universal human right. Consequently, the sustainable management of freshwater resources has gained importance at regional, international and global scales. However, the activities of humankind affect freshwater resources extensively, in terms of both quantity and quality, through a variety of activities ranging from abstraction of water for drinking and irrigation to waste disposal. Today, worldwide freshwater ecosystems are undergreat pressure and are one of the most endangered ecosystems. Furthermore, climate change, especially in relation to precipitation patterns and flooding, will result in the traditional norms being replaced with increased variability and unpredictability, with knock-on effects for human societies and well-being.
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Nutrient Load Apportionment to Support the Identification of Appropriate Water Framework Directive Measures

Nutrient Load Apportionment to Support the Identification of Appropriate Water Framework Directive Measures Mockler, Eva M.; Deakin, Jenny; Archbold, Marie A.; Daly, Donal; Bruen, Michael A model for predicting the sources of nutrient loads (phosphorus and nitrogen) to water has been developed to support Water Framework Directive (WFD) implementation. This model integrates catchment data and pressure information to enable characterisation of Source-Pathway-Receptor relationships. The Source Load Apportionment Model (SLAM) is a flexible framework for incorporating national data and research to quantify nutrient losses from both point discharges (urban wastewater, industry and septic tank systems) and diffuse sources (pasture, arable, forestry, peatlands etc.). Hydrogeological controls have a strong impact on nutrient fluxes, particularly in agricultural catchments, and have been incorporated into the diffuse agricultural model, the Catchment Characterisation Tool (CCT). This paper describes the SLAM framework, including the CCT, along with the data inputs and assumptions. Results for the Suir catchment matched the measured loads of nitrogen and phosphorus well, and showed that pasture is the dominant source of nitrogen across all sub-catchments. The main sources of phosphorus in sub-catchments varied between diffuse agriculture, wastewater and industrial discharges. A relatively small proportion (13%) of the Suir catchment area requires a reduction in phosphorus emissions to achieve Good Status. In these areas, model results can be used in conjunction with knowledge from local authorities and investigative assessments gathered through the WFD characterisation process to identify significant pressures that contribute excessive nutrient loads. An example of assessing load reduction scenarios is presented to illustrate how modelling can support catchment scientists and managers in identifying appropriate measures. 
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Damage Detection by Drive-by Monitoring Using the Vertical Displacements of a Bridge

Damage Detection by Drive-by Monitoring Using the Vertical Displacements of a Bridge Martinez, Daniel; O'Brien, Eugene J.; Sevillano, Enrique Drive-by monitoring has received increasing attention in recent years, as it has great potential useful for Structural Health Monitoring (SHM) applications. Although direct instrumentation of civil infrastructures has been demonstrated to be a way of detecting damage, it is also a very expensive method as it requires data acquisition, storage and transmission facilities on each bridge. Drive-by constitutes an alternative that allows the monitoring of a bridge without the necessity of installing sensors on it. In this numerical study, the vertical displacements of the bridge are used for damage detection purposes. The goal of this paper is to describe a model that can reproduce the vertical displacements of the bridge when a simulated vehicle is driving through and show how these displacements change with damage. Vertical displacements are calculated before and after damage, so that the sensitivity of the data to bridge damage can be determined. A finite element (FE) model of a simply supported beam interacting with a moving half car is used in this study. Damage is represented as a loss of stiffness in several parts of the bridge. Vertical displacements are generated at a moving reference for healthy and damaged states, corresponding to vehicle location on the bridge. Two options are explored, the first axle and the second one, as the locations to fix the simulated sensor on the vehicle. Sixth International Conference on Structural Engineering, Mechanics and Computation (SEMC 2016), Cape Town, South Africa, 5 to 7 September 2016
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Development of Braided Basalt FRP Rebar for Reinforcement of Concrete Structures

Development of Braided Basalt FRP Rebar for Reinforcement of Concrete Structures Antonopoulou, Sofia; McNally, Ciaran; Byrne, Greg In recent years, the development and use of Fibre Reinforced Polymer composite materials in infrastructure have gained increasing attention worldwide. More specifically, natural mineral fibres such as basalt are currently being developed and are showing promising properties. Within an appropriate polymer matrix, their use as reinforcement in concrete structures offers performance benefits related to their environmentally friendly and non-corrodible nature. In particular, BFRPs have the potential to replace conventional internal steel rebar and thus, to be the next generation material in concrete reinforcement applications. A detailed literature review indicates that a careful selection of the appropriate manufacture technique and design methodology are required in order to prevent brittle failure on a concrete structure reinforced with FRP composite material. This paper reports on how to use the additional helical reinforcement and the braid configuration in order to increase strength, structural ductility and long term durability. Moreover, this study outlines the development of an analytical numerical model to predict the longitudinal elastic modulus of braided composites, as well as its validation by comparison of the results with available data from the literature. 8th International Conference on Fibre-Reinforced Polymer (FRP) Composites in Civil Engineering (CICE 2016), Hong Kong, China, 14-16 December 2016
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Strength assessment of in-situ concrete for the evaluation of structural capacity: State of the art

Strength assessment of in-situ concrete for the evaluation of structural capacity: State of the art Sourav, Shah Nur Alam; Salam Al-Sabah, Abd; McNally, Ciaran With more emphasis on reusing and extending the life of structures, it often becomes necessary to assess the capacity of existing concrete structures. One major component of this assessment relates to the concrete strength. Most reliable results are obtained by taking cores. However, such assessment is ideally made with a combination of destructive and nondestructive testing to minimise damage to the structure. The currently available methods for assessing in-situ concrete strength of the existing structures can be broadly divided into two groups. One group of tests is completely non-destructive. The other group is partially destructive where limited damage to the surface is caused by the tests. For the strength evaluation of existing concrete, methods such as surface hardness test, ultrasonic pulse velocity test, penetration resistance test and maturity test fall under the non-destructive category. Partially destructive tests include pull out test, CAPO test, pull off test and break off test. This paper critically evaluates and analyses the applicability and limitations of the methods used for evaluating concrete strength in existing structures. Most methods for strength evaluation are found to measure a certain property such as elasticity, density, tensile strength or hardness of concrete and then relate the measured value to compressive strength. Studies on these methods show a wide variation in the correlations between estimated and predicted compressive strength. Partially destructive methods are noted to provide correlations with good consistency between estimated and predicted compressive strength. Civil Engineering Research in Ireland Conference (CERI 2016), Galway, Ireland, 29-30 August 2016
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State of Technology Review of Civilian UAVs

State of Technology Review of Civilian UAVs Chen, Siyuan; Laefer, Debra F.; Mangina, Eleni Background: Unmanned Aerial Vehicle (UAV) technology has exploded in recent years. Presently UAVs are beginning to be major in roads into geographical mapping, site inspection, agriculture, and search and rescue. Methods: This paper reviewed patents and papers worldwide related to both hardware and software for the construction and deployment of UAVs and is intended to provide a snapshot of currently available UAV technologies, as well as to identify recent trends and future opportunities in affiliated hardware and software. Results: Basic components related to self-designed units are explained (e.g. platform selection, autopilot control comparison and sensor selection), and current applications and research areas are discussed. Since autonomous navigation is a key technology in UAV applications, concepts about this are also explained. Conclusions: Both in the self-designed and commercial markets, UAV components are becoming modularized. By following a standard components list, it is no longer difficult to make a customised UAV. In this way, commercial products are becoming cheaper and more standardized in their performance. Current limitations of UAVs has also become more readily detectible. Extending the flight time, improving autonomous navigation abilities, and enriching the payload capacity will be the future research focus to address these limitations.
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