College of Engineering & Architecture

Odour and ammonia emissions from intensive poultry units in Ireland

2013-05-16T11:39:42Z

Odour and ammonia emissions from intensive poultry units in Ireland Hayes, E. T.; Curran, Thomas P.; Dodd, V. A. Odour and ammonia emissions were measured from three broiler, two layer and two turkey houses in Ireland. The broiler units gave a large range of odour and ammonia emission rates depending on the age of the birds and the season. A considerable variation between the odour and ammonia emission rates was evident for the two layer units which may have been due to the different manure handling systems utilised in the houses. There was relatively little difference in the odour and ammonia emissions from the two turkey houses. As a precautionary principle, odour emission rates utilised in atmospheric dispersion models should use the maximum values for broilers and turkeys (1.22 and 10.5 ou(E) s(-1) bird(-1) respectively) and the mean value for the layers depending on the manure handling system used (0.47 or 1.35 ou(E) s(-1) bird(-1).

Assessment of the influence of media particle size on the biofiltration of odorous exhaust ventilation air from a piggery facility

2013-05-16T11:39:59Z

Assessment of the influence of media particle size on the biofiltration of odorous exhaust ventilation air from a piggery facility Sheridan, B. A.; Curran, Thomas P.; Dodd, V. A. Two pilot scale biofiltration systems were constructed and installed at the University College Dublin Research Farm, Lyons Estate. Experimental units consisting of two pens in a 12 pen pig house were sealed off from other pens. Air from each pen was extracted and treated separately in two biofiltration systems. Wood chips larger than 20 mm were selected as the medium for biofiltration system 1, whereas chips of between 10 and 16 mm were used in biofiltration system 2. The moisture content of the media was maintained at 69±4% (w.w.b.) using a load cell method. The volumetric loading rates ranged from 769 to 1847 m3 [gas] m-3 [medium] h-1 over a 63-day experimental period. Both biofilters reduced odour between 88% and 95%. Ammonia removal efficiencies ranged from 64% to 92% and 69% to 93% for biofiltration systems 1 and 2, respectively. Sulphur-containing compounds were reduced between 9-66% and -147-51% across biofiltration systems 1 and 2. The pH of the biofilters' leachate remained between 6 and 8. Pressure drop for biofilter 2 was 16 Pa greater than that of biofilter 1 at the maximum volumetric loading rate of . It is recommended that a wood chip media particle size greater than 20 mm be used for large scale operation of a biofiltration system on intensive pig production facilities to reduce the development of anaerobic zones and to minimize pressure drop on the system fans.

Practical Experience with Woody Biomass in a Down-Draft Gasifier

2013-05-14T16:30:41Z

Practical Experience with Woody Biomass in a Down-Draft Gasifier Wolff, Deidre; Walsh, Eilín; McDonnell, Kevin Gasification is the cleanest method of obtaining energy from fossil fuels, but with increasing awareness of depleting fossil fuel reserves attention has shifted towards renewable sources of energy. Any carbonaceous material can be gasified to generate high-value end-products from otherwise potentially low-value materials. Gasification can also generate energy from purpose-grown bioenergy crops, and Ireland has an ideal climate to produce woody biomass for energy generation. This update outlines some preliminary results from an investigation into the most suitable woody feedstock for small-scale localised gasification to produce a synthetic gas suitable for use in internal combustion engines. Argentinean- and German-standard wood pellets and Irish-grown willow chips were gasified in a down-draft gasifier. Operation of the gasifier led to the observation that the willow chips bridged within the feedstock hopper which prevented completion of gasification. Implementing a stirring bar in the feedstock hopper prevented bridging and gasification was then successful. Collection of the gas produced during gasification of willow chip was unsuccessful, however gas composition analysis indicates pellets which meet the German-standard are more suitable than Argentinean-standard pellets for use in a down-draft gasifier; work is underway to determine the composition of willow-derived synthetic gas to determine the most suitable feedstock for decentralised gasification by rural communities in Ireland as part of smart farming systems.

The importance of laboratory water quality for studying initial bacterial adhesion during NF filtration processes

2013-05-07T12:06:57Z

The importance of laboratory water quality for studying initial bacterial adhesion during NF filtration processes Correia-Semiao, Andrea Joana; Habimana, O.; Cao, H.; Heffernan, R.; Safari, Ashkan; Casey, Eoin Biofouling of nanofiltration (NF) and reverse osmosis (RO) membranes for water treatment has been the subject of increased research effort in recent years. A prerequisite for undertaking fundamental experimental investigation on NF and RO processes is a procedure called compaction. This involves an initial phase of clean water permeation at high pressures until a stable permeate flux is reached. However water quality used during the compaction process may vary from one laboratory to another. The aim of this study was to investigate the impact of laboratory water quality during compaction of NF membranes. A second objective was to investigate if the water quality used during compaction influences initial bacterial adhesion. Experiments were undertaken with NF270 membranes at 15 bar for permeate volumes of 0.5L, 2L, and 5L using MilliQ, deionized or tap water. Membrane autopsies were performed at each permeation point for membrane surface characterisation by contact angle measurements, profilometry, and scanning electron microscopy. The biological content of compacted membranes was assessed by direct epi-fluorescence observation following nucleic acid staining. The compacted membranes were also employed as substrata for monitoring the initial adhesion of Ps. fluorescens under dynamic flow conditions for 30 minutes at 5 minutes intervals. Compared to MilliQ water, membrane compaction using deionized and tap water led to decreases in permeate flux, increase in surface hydrophobicity and led to significant buildup of a homogenous fouling layer composed of both living and dead organisms (>10⁶cells.cm−2). Subsequent measurements of bacterial adhesion resulted in cell loadings of 0.2×10⁵, 1.0×10⁵cells×cm−2 and 2.6×10⁵ cells.cm−2 for deionized, tap water and MilliQ water, respectively. These differences in initial cell adhesion rates demonstrate that choice of laboratory water can significantly impact the results of bacterial adhesion on NF membranes. Standardized protocols are therefore needed for the fundamental studies of bacterial adhesion and biofouling formation on NF and RO membrane. This can be implemented by first employing pure water during all membrane compaction proceduresand for the modelled feed solutions used in the experiment.

Regional integration of renewable energy systems in Ireland - The role of hybrid energy systems for small communities

2013-05-01T10:36:10Z

Regional integration of renewable energy systems in Ireland - The role of hybrid energy systems for small communities Goodbody, Craig; Walsh, Eilín; McDonnell, Kevin; Owende, Philip Due to a lack of indigenous fossil energy resources, Ireland's energy supply constantly teeters on the brink of political, geopolitical, and geographical unease. The potential risk to the security of the energy supply combined with the contribution of anthropogenic greenhouse gas emissions to climate change gives a clear indication of Ireland's need to reduce dependency on imported fossil fuels as primary energy source. A feasibility analysis to investigate the available renewable energy options was conducted using HOMER software. The net present cost, the cost of energy, and the CO2 emissions of each potential energy combination were considered in determining the most suitable renewable and non-renewable hybrid energy system. Wind energy was shown to have the greatest potential for renewable energy generation in Ireland: wind energy was a component of the majority of the optimal hybrid systems both in stand-alone and grid-connected systems. In 2010 the contribution of wind energy to gross electricity consumption in Ireland approximated 10%, and the results of this feasibility study indicate that there is great potential for wind-generated energy production in Ireland. Due to the inherent variability of wind energy the grid-connected system results are particularly relevant, which show that in more than half of the analyses investigating electrical energy demand the incorporation of wind energy offset the CO2 emissions of the non-renewable elements to such a degree that the whole system had negative CO2 emissions, which has serious implications for Kyoto Protocol emissions limits. Ireland also has significant potential for hydropower generation despite only accounting for 2% of the gross electricity consumption in 2010. Wind and hydro energy should therefore be thoroughly explored to secure an indigenous primary energy source in Ireland.

Functional Assessment for Predicting Charge-Transfer Excitations of Dyes in Complexed State: A Study of Triphenylamine-Donor Dyes on Titania for Dye-Sensitized Solar Cells

2013-05-01T10:29:43Z

Functional Assessment for Predicting Charge-Transfer Excitations of Dyes in Complexed State: A Study of Triphenylamine-Donor Dyes on Titania for Dye-Sensitized Solar Cells Dev, Pratibha; Agrawal, Saurabh; English, Niall J. Time-dependent density functional theory (TD-DFT) was employed to calculate the UV/vis spectra for three of the triphenylamine (TPA)-donor dyes, TC1, L1, and LJ1, in isolation as well as when complexed with a titania nanoparticle. TPA-donor dyes are a class of promising organic dyes for use in dye-sensitized solar cells (DSSCs). The three dyes studied here are among the smallest of these molecules and provide important insight into the entire series of TPA dyes that are being explored as possible sensitizers in titania-based DSSCs. An attempt to calculate the optical spectra for these dyes within the B3LYP approximation to the exchange correlation functional produces erroneous results. However, Coulomb attenuated approximation (CAM-B3LYP) captures the correct photophysics of the dyes and produces more accurate charge-transfer excitation energies of their complexes with titania. This work shows that the extent to which a given approximation fails or succeeds to correctly predict the charge-transfer excitation energies in the isolated dyes is propagated in that it fails (or succeeds) to correctly predict the values of the excitation energies for the complexes. It is, therefore, important to determine the most appropriate functional for a dye before considering it in more complicated structures such as dye-titania complexes.

Comparative studies for evaluation of CO2 fixation in the cavity of the Rubisco enzyme using QM, QM/MM and linear-scaling DFT methods

2013-04-30T13:38:26Z

Comparative studies for evaluation of CO2 fixation in the cavity of the Rubisco enzyme using QM, QM/MM and linear-scaling DFT methods El-Hendawy, Morad M.; English, Niall J.; Mooney, Damian A. We evaluate the minimum energy configuration (MM) and binding free energy (QM/MM and QM) of CO2 to Rubisco, of fundamental importance to the carboxylation step of the reaction. Two structural motifs have been used to achieve this goal, one of which starts from the initial X-ray Protein Data Bank structure of Rubisco's active centre (671 atoms), and the other is a simplified, smaller model (77 atoms) which has been used most successfully, thus far, for study. The small model is subjected to quantum chemical density functional theory (DFT) studies, both in vacuo and using implicit solvation. The effects of the protein environment are also included by means of a hybrid quantum mechanical/molecular mechanical (QM/MM) approach, using PM6/AMBER and B3LYP/AMBER schemes. Finally, linear-scaling DFT methods have also been applied to evaluate energetic features of the large motif, and the result obtained for the binding free energy of the CO2 underlines the importance of the accurate modelling of the surrounding protein milieu using a full DFT description.

A preliminary investigation on face recognition as a biometric identifier of sheep

2013-04-29T11:38:07Z

A preliminary investigation on face recognition as a biometric identifier of sheep Corkery, Gerard; Gonzales-Barron, Ursula A.; Butler, Francis; McDonnell, Kevin; Ward, Shane The suitability of face recognition was investigated as a biometric-based identifier for sheep using a holistic analysis of face images by the independent components technique. Algorithm training was performed independently on several normalized face images from 50 sheep (sets of two, three, and four training images per sheep). The performance of this technique was assessed on a separate set of images (three normalized face images per sheep) using the cosine distance classifier. When 180 to 200 components were extracted, the recognition rate was as high as 95.3% to 96%. As expected, fewer independent components reduced the recognition rate, while a higher number of training images per sheep improved it. Although our results have demonstrated the potential of face recognition as a non-invasive, inexpensive, and accurate novel biometric identifier of sheep, further work should aim at improving recognition rates on a larger set of sheep faces.

The influence of measurement methodology on soil infiltration rate

2013-04-25T13:55:41Z

The influence of measurement methodology on soil infiltration rate Walsh, Eilín; McDonnell, Kevin The recorded rate at which water infiltrates into a soil is influenced by the physical condition of the soil, current and previous uses of the soil and the method and equipment used to record the infiltration rate. Soil’s natural variability and the potential inaccuracy associated with particular methods can overestimate infiltration rate. To determine the most suitable apparatus for repeated use at a small-scale, a number of trials were conducted to investigate the influence of the method and moisture regime on the recorded infiltration rate. Trials were conducted on a medium clay-loam soil which has cropping history of maize-winter wheat-grass-grass-grass. It was observed that there was no significant difference in recorded infiltration rates which could be attributed to the practice of pre-saturating the soil prior to measuring infiltration rate. Furthermore, there was no significant difference between the rates recorded using a single ring infiltrometer and a double ring infiltrometer, indicating that these methods are equally suitable for infiltration rate determination when working at this scale which facilitates multiple replications in the same location or within a short timeframe.

The Direct Use of Post-Processing Wood Dust in Gas Turbines

2013-04-24T15:48:47Z

The Direct Use of Post-Processing Wood Dust in Gas Turbines Doherty, Alîne; Walsh, Eilín; McDonnell, Kevin Woody biomass is a widely-used and favourable material for energy production due to its carbon neutral status. Energy is generally derived either through direct combustion or gasification. The Irish forestry sector is forecasted to expand significantly in coming years, and so the opportunity exists for the bioenergy sector to take advantage of the material for which there will be no demand from current markets. A by-product of wood processing, wood dust is the cheapest form of wood material available to the bioenergy sector. Currently wood dust is primarily processed into wood pellets for energy generation. Research was conducted on post-processing birch wood dust; the calorific value and the Wobbe Index were determined for a number of wood particle sizes and wood dust concentrations. The Wobbe Index determined for the upper explosive concentration (4000 g/m3) falls within range of that of hydrogen gas, and wood dust-air mixtures of this concentration could therefore behave in a similar manner in a gas turbine. Due to its slightly lower HHV and higher particle density, however, alterations to the gas turbine would be necessary to accommodate wood dust to prevent abrasive damage to the turbine. As an unwanted by-product of wood processing the direct use of wood dust in a gas turbine for energy generation could therefore have economic and environmental benefits.

Limit on Converted Power in Resonant Electrostatic Vibration Energy Harvesters

2013-04-24T15:31:14Z

Limit on Converted Power in Resonant Electrostatic Vibration Energy Harvesters Blokhina, Elena; Galayko, Dimitri; Harte, Peter; Basset, Philippe; Feely, Orla Based on the formal analysis of a resonant electrostatic vibration energy harvester operating in constant-charge mode with a gap-closing transducer, we show that the system displays universal behaviour patterns. In this paper, we treat the harvester as a nonlinear forced oscillator and bound the area of control parameters where the system displays regular harmonic oscillations allowing the conditioning circuit to operate in the most effective mode. Before the system exhibits irregular behaviour, there exists a universal optimal value of normalised converted power regardless of the system design and control parameters.

Comparative economic analysis of full scale MABR configurations

2013-04-18T16:47:45Z

Comparative economic analysis of full scale MABR configurations Casey, Eoin; Syron, Eoin; Shanahan, John W.; Semmens, Michael J. The membrane-aerated biofilm reactor (MABR) is a technology that can deliver oxygen at high rates and transfer efficiencies. This paper provides a comparative cost analysis of the MABR compared to the activated sludge process. Membrane cost and electricity cost were found to be the critical parameters determining the relative feasibility of the conventional process to the membrane based process. The general downward trend in the market price of membranes and the steady increase in energy costs in recent years may prove to be a strong driver for the further development of this technology. 2008 IWA North American Membrane Research Conference, University of Massachusetts, Amherst, USA, August 10-13, 2008

Monitoring environmental parameters in poultry production facilities

2013-04-18T11:35:00Z

Monitoring environmental parameters in poultry production facilities Corkery, Gerard; Ward, Shane; Kenny, Colum; Hemmingway, Phil Increases in fuel and feed prices are placing a significant burden on the poultry industry in Ireland and worldwide. For producers to meet their financial targets, increased performance and output is a key issue, now more than ever. To optimise performance in broiler production houses, the effect of environmental and air quality parameters on bird performance and energy consumption must be known to allow farmers make informed management decisions. This paper concentrates on the application precision livestock farming sensors to develop recommendations for improved bird performance and energy consumption in broiler production farms in Ireland. Air temperature, relative humidity, light, air speed and air quality (in particular CO2 and NH3 concentrations) are identified as important parameters for improving bird performance and energy consumption in broiler production houses. Several of these parameters (temperature, relative humidity, CO2 and NH3) were monitored on two farms during the study over the initial 2 weeks of the production cycle. Air quality was often overlooked during the production process, as farmers struggled to limit high heating and feed costs. However, elevated levels of CO2 (>3000 ppm) did not appear to affect broiler growth rates. Additionally, a strong correlation was observed between relative humidity and NH3 (R2 = 0.86 - 0.92). Producers tend to use relative humidity as an indication for NH3 levels and the research shown in this study confirms the close relationship between the two parameters. It is recommended that further data should be gathered from producing units and novel performance technologies should also be investigated. Computer Aided Process Engineering - CAPE Forum 2013, 2013

Evaluation of the odour reduction potential of alternative cover materials at a commercial landfill

2013-05-16T11:40:17Z

Evaluation of the odour reduction potential of alternative cover materials at a commercial landfill Solan, P. J.; Dodd, V. A.; Curran, Thomas P. The availability of virgin soils and traditional landfill covers are not only costly and increasingly becoming scarce, but they also reduce the storage capacity of landfill. The problem can be overcome by the utilisation of certain suitable waste streams as alternative landfill covers. The objective of this study was to assess the suitability of Construction & Demolition fines (C&D), Commercial & Industrial fines (C&I) and woodchip (WC) as potential landfill cover materials in terms of odour control. Background odour analysis was conducted to determine if any residual odour was emitted from the cover types. It was deemed negligible for the three materials. The odour reduction performance of each of the materials was also examined on an area of an active landfill site. A range of intermediate cover compositions were also studied to assess their performance. Odour emissions were sampled using a Jiang hood and analysed. Results indicate that the 200 mm deep combination layer of C&D and wood chip used on-site is adequate for odour abatement. The application of daily cover was found to result in effective reduction allowing for the background odour of woodchip.

A new microplate procedure for simultaneous assessment of lipophilic and hydrophilic antioxidants and pro-oxidants, using crocin and β-carotene bleaching methods in a single combined assay: Tea extracts as a case study

2013-05-01T10:33:05Z

A new microplate procedure for simultaneous assessment of lipophilic and hydrophilic antioxidants and pro-oxidants, using crocin and β-carotene bleaching methods in a single combined assay: Tea extracts as a case study Prieto Lage, Miguel Ángel; Murado García, Miguel Anxo; Vázquez Álvarez, José Antonio; Anders, Yvonne; Curran, Thomas P. β-Carotene and crocin bleaching reactions are the basis of two methods extensively used to quantify antioxidant and pro-oxidant activities. They are appropriate for lipophilic and hydrophilic matrices, respectively, and can provide useful complementary information in the study of complex natural extracts containing components with variable degrees of polarity. In this regard, a microplate procedure (Carotene Combined Bleaching) is proposed that enables the combination of both methods in a single, informative and less expensive method which is also faster to carry out. As an illustrative model, the method was applied to test a set of commercial lipophilic and hydrophilic antioxidants and some predictable pro-oxidant agents. Afterwards, as a food compound case study, the antioxidant activity of five types of tea extracts (Green, Blue, White, Black and Red) were characterized and their equivalent potential activity was calculated using commercial antioxidants on the basis of the new procedure developed in this research. The activity of the tea extracts decreased in the following order: (a) In a predominantly lipophilic environment: White > Black > Red > Blue > Green tea extracts; and (b) In a predominantly hydrophilic environment: Green > Red > White > Black > Blue tea extracts

Numerical and finite element analysis of heat transfer in a closed loop geothermal system

2013-04-08T14:28:55Z

Numerical and finite element analysis of heat transfer in a closed loop geothermal system Hemmingway, Phil; Tolooiyan, Ali Analysis of the thermal regime created by a geothermal borehole heat exchanger is performed using a closed form radial heat flow equation, a geothermal borehole heat exchanger design tool and a finite element model. Climatic, heat exchanger construction and building load data are entered into the heat exchanger design tool in order to create a theoretical model along with thermal parameters from a number of geological formations. Output data from the design tool model are used in conjunction with the closed form radial heat flow equation to calculate the predicted temperature with respect to time and distance from the heat exchanger for the modelled ground formations. The output data from the design tool is also used to create a number of finite element method models against which the predictions calculated using the closed form radial heat flow equation can be compared. A good correlation between the temperatures predicted by the finite element models and the closed form equation calculations is observed. However when used within its recommended limiting conditions, the closed form equation is shown to slightly underestimate the temperature of the ground when compared to the finite element model predictions. The limiting conditions associated with the closed form equation are discussed in the context of the output from the finite element method models.

Vibrational Spectroscopy for Analysis of Water for Human Use and in Aquatic Ecosystems

2013-04-05T10:57:51Z

Vibrational Spectroscopy for Analysis of Water for Human Use and in Aquatic Ecosystems Gowen, Aoife; Tsenkova, R.; Bruen, Michael; O'Donnell, O'Donnell, C. P. (Colm P.) Maintaining a clean water supply is one of the key challenges facing humanity today. Pollution, over-use and climate change are just some of the factors putting increased pressure on our limited water resources. Contamination of the water supply presents a high risk to public health, security and the environment; however, no adequate real-time methods exist to detect the wide range of potential contaminants. There is a need for rapid, low cost, multi target systems for water quality monitoring. Information rich techniques such as vibrational spectroscopy have been proposed for this purpose. This review presents developments in the applications of vibrational spectroscopy to water quality monitoring over the past 20 years, identifies emerging technologies and discusses future challenges.

Parameter sensitivity of a watershed-scale flood forecasting model as a function of modelling time-step

2013-04-05T10:45:01Z

Parameter sensitivity of a watershed-scale flood forecasting model as a function of modelling time-step O'Loughlin, Fiachra; Bruen, Michael; Wagener, Thorsten Despite significant developments, the simple, lumped, conceptual, rainfall-runoff model is still widely used for flood forecasting. What may not be appreciated is that, while such models can often be calibrated to give reasonable forecasts of flood flows, both parameter values and the fluxes of water through individual model components change significantly with the time step used. This means that such models should be used with caution for studies which require “internal” information, such as hydrograph separation or water quality studies that depend on knowing the fluxes through individual flow routes through the model and in studies which try to relate parameter values to physical features of the catchment. To demonstrate this time-scale limitation, a parameter sensitivity analysis was performed on a typical lumped conceptual model (SMARG) applied to a small rural catchment on the Irish East Coast for a number of different time-steps, flow regimes and evaluation metrics. A global sensitivity analysis method (GUI-HDMR, is applied to calculate sensitivity indices which varied greatly with time-step and evaluation metric used. The sensitivity of parameters also differed for different flow regimes. Care should be taken in using internal information and calibrated parameter in conceptual models because of the strong dependence on time-step.

The impact of a catastrophic storm event on benthic macroinvertebrate communities in upland headwater streams and potential implications for ecological diversity and assessment of ecological status

2013-04-03T11:35:14Z

The impact of a catastrophic storm event on benthic macroinvertebrate communities in upland headwater streams and potential implications for ecological diversity and assessment of ecological status Feeley, Hugh B.; Davis, Stephen; Bruen, Michael; Blacklocke, Sean; Kelly-Quinn, Mary Upland headwater streams are dynamic systems, responding rapidly to changes in climatic conditions. This study examined the effects of a catastrophic rainfall event, that occured on 24 October 2011 on the east coast of Ireland, on the macroinvertebrate community composition and structure of four headwater streams in the river Liffey catchment located in the Wicklow Mountains. The ecological status before and after the storm were also evaluated. The water level and pH of each stream were recorded using continuous monitoring equipment, while rainfall data for the study period were sourced from a local weather station. Benthic macroinvertebrates were investigated before and after the storm event using Surber sampling. Results showed rapid and large increases in water level and significant declines in stream pH in response to intensive rainfall during the storm. The high water levels also caused major physical damage and abrasion in all four streams, that significantly altered instream habitats. The storm event induced significant losses to the richness and/or density of most taxonomic groups, with the exception of the Plecoptera. Furthermore, the overall community composition and structure changed significantly, most likely as a result of physical disturbance, given the relative persistence of acid-sensitive taxa and the relatively short period of harsh acidic conditions (<5 pH). Interestingly however, the ecological status of each of the four study sites, tested using Stream Risk Score (SSRS), Biological Monitoring Working Party (BMWP) and the Average Score Per Taxon (ASPT) indices, was unaltered by the loss in richness and densities. This was likely a result of the maintenance of plecopteran richness and the absence of organic pollution, thus highlighting the need to develop appropriate indices to assess the ecological status of streams and rivers affected by physical disturbance caused by large storm events. Ultimately, catastrophic storm events in upland headwater streams have potentially major implications for the maintenance of regional macroinvertebrate diversity within affected regions.

Derivation of a national fuzzy phosporous export model using 84 Irish catchments

2013-03-20T13:03:28Z

Derivation of a national fuzzy phosporous export model using 84 Irish catchments Nasr, Ahmed Elssidig; Bruen, Michael Implementation of appropriate management strategies to mitigate diffuse phosphorus (P) pollution at the catchment scale is vitally important for the sustainable development of water resources in Ireland. An important element in the process of implementing such strategies is the prediction of their impacts on P concentrations in a catchment using a reliable mathematical model. In this study, a state-of-the-art adaptive neuro-fuzzy inference system (ANFIS) has been used to develop a new national P model capable of estimating average annual ortho-P concentrations at un-gauged catchments. Data from 84 catchments dominated by diffuse P pollution were used in developing and testing the model. Six different split-sample scenarios were used to partition the total number of the catchments into two sets, one to calibrate and the other to validate the model. The k-means clustering algorithm was used to partition the sets into clusters of catchments with similar features. Then for each scenario and for each cluster case, 11 different models, each of which consists of a linear regression sub-model for each cluster, were formulated by using different input variables selected from among six spatially distributed variables including phosphorus desorption index (PDI), runoff risk index (RRI), geology (GEO), groundwater (GW), land use (LU), and soil (SO). The success of the new approach over the conventional lumped, empirical, modelling approach was evident from the improved results obtained for most of the cases. In addition the results highlighted the importance of using information on PDI and RRI as explanatory input variables to simulate the average annual ortho-P concentrations.

Dye sensitised solar cells with nickel oxide photocathodes prepared via scalable microwave sintering

2013-03-20T12:40:08Z

Dye sensitised solar cells with nickel oxide photocathodes prepared via scalable microwave sintering Gibson, Elizabeth A.; Awais, Muhammad; Dini, Danilo; Dowling, Denis P.; Pryce, Mary T.; Vos, Johannes G.; Boschloo, Gerrit; Hagfeldt, Anders Photoactive NiO electrodes for cathodic dye-sensitised solar cells (p-DSCs) have been prepared with thicknesses ranging between 0.4 and 3.0 mm by spray-depositing pre-formed NiO nanoparticles on fluorine-doped tin oxide (FTO) coated glass substrates. The larger thicknesses were obtained in sequential sintering steps using a conventional furnace (CS) and a newly developed rapid discharge sintering (RDS) method. The latter procedure is employed for the first time for the preparation of p-DSCs. In particular, RDS represents a scalable procedure that is based on microwave-assisted plasma formation that allows the production in series of mesoporous NiO electrodes with large surface areas for p-type cell photocathodes. RDS possesses the unique feature of transmitting heat from the bulk of the system towards its outer interfaces with controlled confinement of the heating zone. The use of RDS results in a drastic reduction of processing times with respect to other deposition methods that involve heating/calcination steps with associated reduced costs in terms of energy. P1-dye sensitized NiO electrodes obtained via the RDS procedure have been tested in DSC devices and their performances have been analysed and compared with those of cathodic DSCs derived from CS-deposited samples. The largest conversion eﬃciencies (0.12%) and incident photon-to-current conversion eﬃciencies, IPCEs (50%), were obtained with sintered NiO electrodes having thicknesses of B1.5–2.0 mm. In all the devices, the photogenerated holes in NiO live significantly longer (th B 1 s) than have previously been reported for P1-sensitized NiO photocathodes. In addition, P1-sensitised sintered electrodes give rise to relatively high photovoltages (up to 135 mV) when the triiodide–iodide redox couple is used.

Achieving enhanced DSSC performance by microwave plasma incorporation of carbon into TiO2 photoelectrodes

2013-03-20T12:35:07Z

Achieving enhanced DSSC performance by microwave plasma incorporation of carbon into TiO2 photoelectrodes Dang, Binh H.Q.; MacElroy, J. M. Don; Dowling, Denis P. The photoactivity of carbon-incorporated titanium dioxide (TiO2) has been widely reported. This study involves a novel approach to the incorporation of carbon into TiO2 through the use of microwave plasma processing. The process involved thermally treating printed TiO2 nanoparticle coatings in a microwave-induced argon-oxygen plasma containing low concentrations of methane. The resulting deposited carbon layer was characterized using XRD, XPS, Raman, UV–vis, ellipsometry, and optical profilometry. It was found that the methane gas was dissociated in the microwave plasma into its carbon species, which were then deposited as a nm-thick layer onto the TiO2 coatings, most likely in the form of graphite. The photovoltaic performances of both the TiO2 and the carbon-incorporated TiO2 were assessed through J-V and IPCE measurements of the N719-sensitized solar cells using the titania as their photoanodes. Up to a 72% improvement in the maximum power density (Pd-max) was observed for the carbon-incorporated TiO2 samples as compared to the TiO2, onto which no carbon was added. This improvement was found to be mainly associated with an increase in the short-circuit current density (Jsc), but independent from the open-circuit voltage (Voc), the filter factor (FF), and the level of dye adsorption. Possible contributory factors to the improved performance of the carbon-incorporated TiO2 were the enhanced electron conductivity and electron lifetime, both of which were elucidated through electrochemical impedance spectroscopy (EIS). When the surface layer was examined using XPS, the optimal carbon content on the TiO2 coating surface was found to be 8.4%, beyond which there was a reduction in the DSSC efficiency.

Spray deposited NiOx films on ITO substrates as photoactive electrodes for p-type dye-sensitized solar cells

2013-03-20T12:22:03Z

Spray deposited NiOx films on ITO substrates as photoactive electrodes for p-type dye-sensitized solar cells Awais, Muhammad; Dowling, Denis P.; Rahman, Mahfujur; Vos, Johannes G.; Decker, Franco; Dini, Danilo Spray deposition followed by sintering of nickel oxide (NiO x ) nanoparticles (average diameter: 40 nm) has been chosen as method of deposition of mesoporous NiO x coatings onto indium tin oxide (ITO) substrates. This procedure allows the scalable preparation of NiO x samples with large surface area (~103 times the geometrical area) and its potential for applications such as electrocatalysis or electrochemical solar energy conversion, which require high electroactivity in confined systems. The potential of these NiO x films as semiconducting cathodes for dye-sensitized solar cell (DSC) purposes has been evaluated for 0.3–3-μm-thick films of NiO x sensitized with erythrosine B (ERY). The electrochemical processes involving the NiO x coatings in the pristine and sensitized states were examined and indicated surface confinement as demonstrated by the linear dependence of the current densities with the scan rate of the cyclic voltammetry. Cathodic polarization of NiO x on ITO can also lead to the irreversible reduction of the underlying ITO substrate because of the mesoporous nature of the sintered NiO x film that allows the shunting of ITO to the electrolyte. ITO-based reduction processes alter irreversibly the properties of charge transfer through the ITO/NiOx interface and limit the range of potential to NiO x coatings sintered for DSC purposes.

Studying the variability and uncertainty impacts of variable generation at multiple timescales

2013-03-14T17:35:13Z

Studying the variability and uncertainty impacts of variable generation at multiple timescales Ela, Erik; O'Malley, Mark With increasing levels of variable renewable energy, there is a growing need to study its impacts on power system operation. Variable generation (VG) is variable and uncertain at multiple timescales, and it is important that system operators understand how each of these characteristics impact their systems since each may have different mitigation strategies. To date, many of the studies of VG integration are limited to studying at one time resolution and therefore cannot analyze the variability and uncertainty impacts across multiple timescales. Here we study the variability and uncertainty impacts across multiple operational timescales. A model is used which integrates multiple scheduling sub-models with different update frequencies, time resolutions, and decision horizons. Using metrics that describe reliability and costs with a methodology that describes the sensitivities and tradeoffs of variability and uncertainty impacts separately with respect to the conditions that cause those impacts, case studies are performed which display greater information on expectations of these impacts on future systems with high penetrations of VG.

Bankfull discharge and recurrence intervals in Irish rivers

2013-05-16T11:43:46Z

Bankfull discharge and recurrence intervals in Irish rivers Ahilan, Sangaralingam; O'Sullivan, J. J.; Bruen, Michael; Brauders, Neill; Healy, Darren Different definitions of the bankfull condition in rivers are based on morphological characteristics, boundary conditions and geometrical properties. Consequently, the magnitude and associated return period of the bankfull discharge can be ambiguous. Knowledge of this discharge is important in index flood estimation and subsequent regional flood frequency analysis. This study investigates bankfull discharges and recurrence intervals at 88 locations in the Irish river network using a combination of surveyed bankfull levels, rating curves and equations and photographic records at the sites in question. Catchments ranged in area from approximately 23 km2 to 2778 km2. Recurrence intervals were determined by fitting generalised extreme value (GEV) distributions to the annual maximum flow series at the sites investigated. These intervals were found to be less than 2 years (the median annual flood) at 42 stations (48%) and less than 2·33 years (the mean annual flood assuming a GEV type 1 distribution) at 47 stations (53%). Higher return periods of between 2·33 and 10 years and 10 and 25 years were observed at a further 20% and 6% of locations respectively. Using multivariate regression analysis, the computed bankfull discharges are correlated with catchment descriptors and three expressions are presented for estimating bankfull flows.

The Shaft Capacity of Displacement Piles in Clay: A State of the Art Review

2013-03-14T15:09:17Z

The Shaft Capacity of Displacement Piles in Clay: A State of the Art Review Doherty, Paul; Gavin, Kenneth The rapid expansion of the offshore wind sector, coupled with increasing demand for high rise structures, has placed renewed demand on the driven piling market. In light of this industry growth, this paper reviews the evolution of design approaches for calculating the shaft capacity of displacement piles installed in cohesive soils. The transition from traditional total stress design towards effective stress methods is described. Complex stress–strain changes occur during pile installation, equalisation and load testing and as a consequence, the selection of parameters for use in conventional earth-pressure type effective stress approaches is not straight-forward. These problems have led to the development of empirical correlations between shaft resistance and in situ tests, such as the cone penetration tests. However, many of these approaches are limited because they were developed for specific geological conditions. Significant insight into pile behaviour has been obtained from recent model pile tests, which included reliable measurements of radial effective stresses. These tests have allowed factors such as friction fatigue and interface friction to be included explicitly in design methods. Whilst analytical methods have been developed to investigate pile response, these techniques cannot yet fully describe the complete stress–strain history experienced by driven piles. The use of analytical methods in examining features of pile behaviour, such as the development of pore pressure during installation and the effects of pile end geometry on pile capacity, is discussed.

Retaining walls in Dublin Boulder Clay, Ireland

2013-03-14T15:07:08Z

Retaining walls in Dublin Boulder Clay, Ireland Long, Michael (Michael M.); Brangan, Carl; Menkiti, Christopher O.; Looby, Michael; Casey, Patrick A good number of deep excavations have been recently completed in Dublin Boulder Clay, Ireland. These have included propped walls up to 25 m deep and permanent cantilevers 7.5 m high. Experience elsewhere in the world was used to design and construct these walls. However, case history data have shown that the behaviour of the walls in Dublin Boulder Clay is very rigid and much stiffer than comparable systems worldwide. It appears this behaviour is due to the inherent natural strength and stiffness of the soil and the slow dissipation of excavation induced depressed pore pressures or suctions. There appears to be scope for developing more efficient designs and in particular for reducing propping requirements. For temporary works, the use of undrained parameters in serviceability limit state calculations together with implementation of the observational approach on site could be considered for future schemes.

Weigh-in-Motion: Recent Developments in Europe

2013-03-14T14:37:15Z

Weigh-in-Motion: Recent Developments in Europe Jacob, Bernard; O'Brien, Eugene J. This paper provides a review of recent European developments in WIM. Pan-European and national projects are reported plus developments in sensor technologies and system design. Recent developments in multiple-sensor WIM systems are given particular attention. The coming of prototype fully-automatic overload systems is discussed and the technologies and legal framework necessary for their success. The commercialisation of Bridge WIM in Europe since the ICWIM3 is considered and the continued development of this technology towards almost maintenance-free systems. WIM applications are also discussed including pavement and bridge design and assessment. 4th International Conference on Weigh-in-Motion - ICWIM4, Taipei, Taiwan, 20-23rd February 2005

Experimental Investigation of Drive-by Bridge Inspection

2013-03-13T17:27:22Z

Experimental Investigation of Drive-by Bridge Inspection Kim, Chul-Woo; Isemoto, R.; Toshinami, T.; Kawatani, M.; McGetrick, P.; O'Brien, Eugene J. This study presents a vibration-based health monitoring strategy for short span bridges utilizing an inspection vehicle. How to screen health condition of short span bridges in terms of the drive-by bridge inspection is described. Feasibility of the drive-by bridge inspection is investigated through a scaled laboratory moving vehicle experiment. The feasibility of using an instrumented vehicle to detect the natural frequency and changes in structural damping of a model bridge is observed. Observations also demonstrate the possibility of diagnosis of bridges by comparing patterns of identified dynamic parameters of bridges through periodical monitoring. It is confirmed that the moving vehicle method identifies the damage location and severity well. 5th International Conference on Structural Health Monitoring of Intelligent Infrastructure (SHMII-5), Cancun, Mexico, 11-15 December, 2011

Finite Element Model Updating Using Cross-Entrophy

2013-03-13T17:20:53Z

Finite Element Model Updating Using Cross-Entrophy Dowling, Jason; González, Arturo; O'Brien, Eugene J.; Walsh, Brian J. This paper presents the potential of the cross-entropy method to surmise the properties of a simply supported beam using as input the response of the structure to a moving load. The beam model is discretised into a number of elementary beams with assumed initial statistical distributions of stiffness. Then, an optimisation procedure based on cross-entropy is employed to minimise differences between simulated measurements and the results of the theoretical finite element beam model. The procedure consists of generating a large sample of stiffness distributions for each elementary beam, and selecting those fitting the measured response best. Then, the parameters of the statistical distribution of stiffness assumed for each elementary beam (mean and standard deviation) are updated using the stiffness values of those combinations of elementary beams giving a best solution. It is an iterative procedure where the mean value of each distribution tends towards the true stiffness in successive iterations. The level of accuracy is limited by the quantity and quality of the available measurements. Therefore, the standard deviation of the final stiffness for each beam element (once further iterations do not lead to a reduction of the error) provides an estimation of the reliability of the prediction. Here, the method is demonstrated for the characterisation of the stiffness distribution of a beam from the simulated response to a moving load. First, deflections are calculated using a finite element beam model with assumed initial stiffness properties. There will be a record of simulated responses per measurement point that cross-entropy will try to imitate by adjusting and improving estimations of stiffness in successive iterations. The results show cross-entropy can be used as a valuable tool to estimate structural parameters and it has huge scope for applications in model calibration, bridge weigh-in-motion and monitoring. Bridge & Infrastructure Research in Ireland 2010, Cork Institute of Technology, September 2010

Finding the Distribution of Bridge Lifetime Load Effect by Predictive Likelihood

2013-03-13T17:16:53Z

Finding the Distribution of Bridge Lifetime Load Effect by Predictive Likelihood Caprani, Colin C.; O'Brien, Eugene J. To assess the safety of an existing bridge, the loads to which it may be subject in its lifetime are required. Statistical analysis is used to extrapolate a sample of load effect values from the simulation period to the required design period. Complex statistical methods are often used and the end result is usually a single value of characteristic load effect. Such a deterministic result is at odds with the underlying stochastic nature of the problem. In this paper, predictive likelihood is shown to be a method by which the distribution of the lifetime extreme load effect may be determined. A basic application to the prediction of lifetime Gross vehicle Weight (GVW) is given. Results are also presented for some cases of bridge loading, compared to a return period approach and important differences are identified. The implications for the assessment of existing bridges are discussed. 3rd International ASRANet Colloquium, held at the University of Glasgow, 10-12 July 2006.

The Determination of Site-Specific Imposed Traffic Loadings on Existing Bridges

2013-03-13T16:59:34Z

The Determination of Site-Specific Imposed Traffic Loadings on Existing Bridges Graves, S.A.; O'Brien, Eugene J.; O'Connor, Alan The Fourth International Conference on Bridge Management

Prediction of Residential BMW Generation According to Socio-Economic And Household Characteristics For The Dublin Region

2013-03-25T11:55:49Z

Prediction of Residential BMW Generation According to Socio-Economic And Household Characteristics For The Dublin Region Purcell, M.; Magette, W. L. Despite the fact that biodegradable wastes account for 72% of the total municipal waste stream in Ireland, less than 6% of collected biodegradable wastes were recovered in 2004. Both planning and design of integrated municipal solid waste management systems require accurate prediction of solid waste generation. This paper discusses the potential household biodegradable municipal waste (BMW) generation for the Dublin Region, Ireland, using statistical data on socio-demographics, particularly household size and social class as the main variables. Historical research was used to assign BMW generation rates. A Geographical Information System (GIS) "model" of BMW generation was created using ArcMap, a component of ArcGIS 9. BMW generation was predicted within a diverse "landscape" of residential areas. The results highlight the importance of tailoring waste management strategies to small management areas. 21st International Waste Management and Landfill Symposium, Sardinia, 1-5 October 2007

Nutrient and Sediment Removal by Vegetated Filter Stips

2013-03-05T15:58:23Z

Nutrient and Sediment Removal by Vegetated Filter Stips Magette, W. L.; Brinsfield, Russell B.; Palmer, Robert E.; Wood, James D. A field study utilizing simulated rainfall and bare plots 5.5m wide by 22m long was conducted to study the effectiveness of vegetated filter strips 4.6 and 9.2m long in removing nutrients and sediments from agricultural runoff. Losses of N and P from plots with filters were highly variable as compared to plots with no filters. Generally, nutrient removals appeared to be greater with the longer filters, but decreased as the number of runoff events increased. Mass losses of TSS, TN and TP in surface runoff were reduced by 66%, 0% and 27%, respectively, by 4.6m (15ft) long filters. TSS, TN and TP reductions by 9.2m (30ft) long filter strips of the lengths utilized in this study were effective in removing sediment from runoff but should not be relied upon as the primary means to reduce nutrient losses from agricultural areas.

Piles for offshore wind turbines: A state of the art review

2013-03-05T15:54:25Z

Piles for offshore wind turbines: A state of the art review Gavin, Kenneth; Igoe, David; Doherty, Paul The paper considers the current state of the art for estimating the pull-out capacity of driven open-ended piles used to support wind turbine foundations founded on sand. The latest edition of the American Petroleum Institute guidelines for pile design includes a conventional earth pressure approach and four alternative cone penetration test (CPT) methods for estimating pile shaft resistance in sand. A database of open-ended pile tests was used to assess the predictive reliability of the design approaches. While the earth pressure approach was unreliable, exhibiting bias with pile slenderness and sand relative density, the CPT methods were shown to provide improved and relatively consistent estimates of pile capacity. However, the tension loads experienced by wind turbine foundations are significantly higher than those applied to piles in the database. When the CPT methods were used to estimate the pile length required to support a 5 MW turbine installed in typical offshore soil conditions, the CPT methods provided a wide range of predicted pile lengths. The reasons for this divergence are discussed and an alternative framework for considering driven pile shaft resistance is put forward.

Performance of concrete incorporating GGBS in aggressive wastewater environments

2013-02-26T15:26:23Z

Performance of concrete incorporating GGBS in aggressive wastewater environments O’Connell, Martin; McNally, Ciaran; Richardson, Mark G. Concrete is traditionally used as the main component of wastewater facilities. The sulfate and acidic environment presents significant challenges. Supplementary cementitious materials (SCM) such as GGBS are being used in increasing quantities in concrete and have been shown to provide concrete with increased durability in this particular environment. They have traditionally been used with CEM I, but in recent years a shift in concrete practice has led to the introduction of CEM II cements with reduced CO2 footprint and obvious environmental and economic benefits. However, the change in cement chemistry associated with using CEM II and GGBS must also be accounted for in concrete specifications for aggressive environments. This has particular importance when concrete is exposed to elevated sulfate and sulfuric acid environments, such as that associated with water and wastewater treatment. The performance of CEM II/A-L cements with varying amounts of GGBS was evaluated through a series of tests conducted to determine their durability characteristics in respect of sulfate attack and sulfuric acid attack. As a benchmark, samples were also tested using CEM I cement, CEM I with GGBS, and a sulfate resistant Portland cement. Results have shown that for all cases, the addition of GGBS resulted in considerable reductions in sulfate induced expansion relative to samples using CEM I or CEM II binders alone. A slight improvement in performance relative to sulfate resisting Portland cement (SRPC) binders was also observed. However in respect of the sulfuric acid environment the regime proved too harsh and ultimately resulted in the early failure of all samples. Some difference in performance was noted, but this was not considered noteworthy. The influence of pH and acid type was studied. The conclusions were that the concretes tested cannot adequately address the durability threat to all parts of wastewater infrastructure over a significant life span due to the extraordinarily harsh nature of this form of attack.

Use of weigh-in-motion (WIM) data for site-specific LRFR bridge rating

2013-02-26T15:20:17Z

Use of weigh-in-motion (WIM) data for site-specific LRFR bridge rating Zhao, Hua; Uddin, Nasim; Waldron, Christopher J.; O'Brien, Eugene J. In this paper, truck weigh-in-motion (WIM) data are used to develop live load factors for use on Alabama state-owned bridges. The factors are calibrated using the same statistical methods that were used in the original development of AASHTO’s Load and Resistance Factor Rating (LRFR) Manual. This paper describes the jurisdictional and enforcement characteristics in the state, the WIM data filtering, sorting, and quality control, as well as the calibration process. Large WIM data sets from five sites were used in the calibration and included different truck volumes, seasonal and directional variations, and WIM data collection windows. Certain MATLAB programs were developed in the live load factor calibration process. The resulting state-specific live load factors are smaller than those of LRFR manual and are recommended to the Alabama Department of Transportation (ALDOT) in rating their bridges more efficiently 6th International Conference on Weigh-in-Motion, ICWIM6, Dallas, 4-7 June, 2012

Load effect of single-lane traffic simulations on long-span bridges

2013-02-26T15:08:49Z

Load effect of single-lane traffic simulations on long-span bridges Lipari, Alessandro; Caprani, Colin C.; O'Brien, Eugene J. It is well acknowledged that long-span road bridges (about 50 m long and more) are governed by congestion traffic rather than free-flow conditions. A conventional model for the design of new long-span bridges is to place over the bridge a load model representing a platoon of heavy vehicle with the gaps between them reduced to a minimum. This assumption is too conservative for existing bridges, given the large disruption costs faced by their closure for rehabilitation. In order to model the close gaps between vehicles, characteristic of congested traffic, microsimulation is needed to accurately capture drivers’ behaviour. In this work, a microsimulation model is studied and found to replicate many different known forms of congestion. As a first approach to the topic, single-lane simulations of identical vehicles have been carried out in order to obtain load effect on a sample bridge. This load effect is studied with reference to the form of traffic causing the load effect. It is found that the most extreme load effect may not be caused by purely congested traffic but also by non-stationary congested conditions Bridge & Infrastructure Research in Ireland 2010, Cork Institute of Technology, 2010

Statistical computation for extreme bridge traffic load effects

2013-02-26T15:05:33Z

Statistical computation for extreme bridge traffic load effects Caprani, Colin C.; O'Brien, Eugene J. The maintenance of highway infrastructure constitutes a major expenditure in many countries. This cost can be reduced significantly by minimizing the repair or replacement of highway bridges. In the assessment of existing bridges, the strength estimate tends to be more accurate than that of traffic loading, due to the more variable nature of loading. Recent advances in the statistical analysis of highway bridge traffic loading have resulted in more accurate forecasts of the actual loading to which a bridge is subject. While these advances require extensive numerical computation, they can significantly improve the accuracy of the calculation. This paper outlines the recent advances and describes the associated computational aspects in detail Eighth International Conference on Computational Structures Technology, Las Palmas de Gran Canaria, Spain, from 12 to 15 September 2006

In situ strength characterisation of peat and organic soil using full-flow penetrometers

2013-02-26T14:56:28Z

In situ strength characterisation of peat and organic soil using full-flow penetrometers Boylan, Noel; Long, Michael (Michael M.); Mathijssen, F.A.J.M. Full-flow penetrometers have been shown to overcome problems experienced with the cone penetrometer when measuring resistance in very soft peat and organic soil, and give a much more uniform measure of resistance than the cone in fibrous peat. However, at present there is no guidance on the interpretation of strength parameters in these soils using the T-bar and ball. This paper examines the results of tests using these devices at two research sites in the Netherlands in conjunction with high-quality Sherbrooke sampling for laboratory testing. In fibrous peat, the T-bar and ball provided a more uniform measure of resistance with a lower degree of scatter than the cone. The in situ testing results have been compared with the laboratory tests to assess the range of resistance factors relating penetration resistance to the undrained shear strength (su) and have been shown to occupy a lower range of values than the cone penetrometer. However, penetration tests in these soils are likely to be influenced by partial drainage effects and this should be considered during testing and the subsequent interpretation of results. Recommendations are made for the use of full-flow penetrometers to obtain strength parameters in these soils.

Water quality monitoring during the construction of the M3 motorway in Ireland

2013-05-16T11:50:10Z

Water quality monitoring during the construction of the M3 motorway in Ireland Purcell, Patrick J.; Bruen, Michael; O'Sullivan, J. J.; Cocchiglia, Letizia; Kelly-Quinn, Mary The M3 motorway in Ireland was constructed between the years 2007 and 2010. The motorway crosses the River Boyne, which is a designated salmonid water under the EU Freshwater directive, and its tributaries. The paper describes the measures taken to mitigate any potential impacts which the road scheme might have had on the aquatic environment and the water quality of the Boyne watercourses before-, during- and post-construction. The success of the mitigation measures undertaken is assessed by: (a) comparing pre-construction, during-construction and post-construction water quality data, (b) comparing measured water quality with relevant standards, (c) comparing water quality data upstream and downstream of river crossings, (d) the establishment of a pilot-scale real-time water quality monitoring station at the downstream end of the works before discharge into the river Boyne. The study concluded that the measures taken have been successful in minimising the water quality impacts associated with the road scheme.

Targeted intervention strategies to optimise diversion of BMW in the Dublin, Ireland region

2013-02-26T14:41:44Z

Targeted intervention strategies to optimise diversion of BMW in the Dublin, Ireland region Purcell, M.; Magette, W. L. Urgent transformation is required in Ireland to divert biodegradable municipal waste (BMW) from landfill and prevent increases in overall waste generation. When BMW is optimally managed, it becomes a resource with value instead of an unwanted by-product requiring disposal. An analysis of survey responses from commercial and residential sectors for the Dublin region in previous research by the authors proved that attitudes towards and behaviour regarding municipal solid waste is spatially variable. This finding indicates that targeted intervention strategies designed for specific geographic areas should lead to improved diversion rates of BMW from landfill, a requirement of the Landfill Directive 1999/31/EC. In the research described in this paper, survey responses and GIS model predictions from previous research were the basis for goal setting, after which logic modelling and behavioural research were employed to develop site-specific waste management intervention strategies. The main strategies devised include (a) roll out of the Brown Bin (Organics) Collection and Community Workshops in Dún Laoghaire Rathdown, (b) initiation of a Community Composting Project in Dublin City (c) implementation of a Waste Promotion and Motivation Scheme in South Dublin (d) development and distribution of a Waste Booklet to promote waste reduction activities in Fingal (e) region wide distribution of a Waste Booklet to the commercial sector and (f) Greening Irish Pubs Initiative. Each of these strategies was devised after interviews with both the residential and commercial sectors to help make optimal waste management the norm for both sectors. Strategy (b), (e) and (f) are detailed in this paper. By integrating a human element into accepted waste management approaches, these strategies will make optimal waste behaviour easier to achieve. Ultimately this will help divert waste from landfill and improve waste management practice as a whole for the region. This method of devising targeted intervention strategies can be adapted for many other regions.

The Development and Testing of an Instrumented Open-Ended Model Pile

2013-02-26T14:39:45Z

The Development and Testing of an Instrumented Open-Ended Model Pile Igoe, David; Doherty, Paul; Gavin, Kenneth This paper describes the development of a model instrumented open-ended (pipe) pile. The importance of model geometry and separating the shaft, annular and plug load, and horizontal effective stresses is discussed. A detailed description of the construction of the twin-walled open-ended pile is presented. Particular attention was given to protecting the fragile instrumentation from the rigours of installation and the effects of water ingress. Calibration procedures, which were used to verify the instrument reliability, are also discussed. The final section describes field tests conducted in both loose sand and medium-dense sand deposits, which are used to validate the instrument performance.

Web-Enabling of Architectural Heritage Inventories

2013-02-26T11:46:10Z

Web-Enabling of Architectural Heritage Inventories Morrish, Sean; Laefer, Debra F. Surveys and inventories of the built environment have improved the understanding of the state of existing heritage structures and historic districts and assisted in their preservation by thorough and consistent documentation. Unfortunately, full exploitation of these resources has been impeded by their static, non-interactive nature as printed documents (ie, reports or maps). This article presents recent attempts to improve access of such resources through their web-enablement. Specifically, issues of usability, relevance, contemporaneousness, and spatial integration are evaluated. These requirements are considered with respect to a new resource, Historic Ireland's Built Environment and Road Network Inventories Access (HIBERNIA). This integrated, extendable database and geographic information system (GIS) is featured as an example of how access to these surveys and inventories can be improved to form the basis for future developments to provide a more complete picture of heritage resources and enable innovative resource management strategies.

Case study of a project-based learning course in civil engineering design

2013-02-26T11:36:13Z

Case study of a project-based learning course in civil engineering design Gavin, Kenneth This paper describes the use of project-based learning to teach design skills to civil engineering students at University College Dublin (UCD). The paper first considers the development of problem-based leaning (PBL) as a tool in higher education. The general issues to be considered in the design of the curriculum for a PBL module are reviewed. Consideration of the literature on the application of PBL in civil engineering suggests that, because of the hierarchical nature of engineering education, PBL is best applied in a hybrid form known as Project Based Learning. A detailed description is given of how hybrid PBL was implemented in the final year of a civil engineering degree programme. In the final section, the results of an evaluation process designed to gain an insight into students’ perceptions of the PBL process are reviewed. The module, which was developed at UCD, provided an excellent mechanism for developing many skills, including problem-solving, innovation, group-working and presentation skills desired by graduate employers. It was clear that the students enjoyed the peer to peer teaching and increased interaction with staff and external experts, which the problem-solving nature of the module facilitated.

Attitudes and behaviour towards waste management in the Dublin, Ireland region

2013-02-20T12:36:32Z

Attitudes and behaviour towards waste management in the Dublin, Ireland region Purcell, M.; Magette, W. L. The hypothesis of this research was that attitudes about the management of biodegradable municipal waste (BMW) are spatially variable, even within a city of modest (1.2 million) population. For a select number of representative electoral districts in the Dublin, Ireland region, residents were surveyed regarding attitudes towards waste management in general, and BMW management in particular. A total of 850 survey responses were collected. Door-to-door interviews produced 688 responses in the residential sector; these were supplemented by 162 responses to a web-based survey. The surveys revealed that the majority of households use local authority, rather than private, waste collection services (both are available). The majority of residents, regardless of the local authority in which they live, were satisfied with their waste management service. “Reducing the quantity of waste generated” was regarded the most important future issue for 28% of residential respondents. Statistical analyses of the survey responses showed that the local authority in which respondents resided significantly influenced most responses (including waste collection service used, waste service satisfaction and backyard composting activity). Many responses (including waste service satisfaction, waste management influences) were also significantly related to the respondents’ personal characteristics (e.g., education level, type of accommodation, age, etc.). These statistical results proved the hypothesis of the research and demonstrated that waste management initiatives designed for one area of the city (or, indeed, for uniform application to the city as a whole) could ignore the needs of other areas. The survey responses suggest that targeted intervention strategies would lead to improved diversion rates of BMW from landfill, a requirement of the Landfill Directive 1999/31/EC.

Shaft Capacity of Open-Ended Piles in Clay

2013-02-20T12:32:15Z

Shaft Capacity of Open-Ended Piles in Clay Doherty, Paul; Gavin, Kenneth This paper describes an experimental investigation designed to assess the impact of pile end condition on the capacity of piles installed in soft clay. A series of field tests are described in which instrumented open-ended and closed-ended model piles were jacked into soft clay. The radial stresses, pore pressures, and load distribution were recorded throughout installation, equalization, and load-testing. Although the total stress and pore pressure developed during installation were related to the degree of soil plugging, the radial effective stress that controls the shaft resistance was shown to be independent of the mode of penetration. The long-term shaft capacity of the open-ended pile was closely comparable to that developed by closed-ended piles, suggesting a limited influence of end condition on the fully equalized shaft resistance. In contrast to the shaft resistance, the base capacity was highly dependent on the degree of plugging.

Cyclic and Rapid Axial Load Tests on Displacement Piles in Soft Clay

2013-02-20T12:30:23Z

Cyclic and Rapid Axial Load Tests on Displacement Piles in Soft Clay Doherty, Paul; Gavin, Kenneth Offshore piles are subjected to complex loading regimes, which include both rapidly applied static and cyclic loads. This note describes an experimental investigation conducted in order to assess the factors influencing the response of offshore piles to these loading conditions. The tests were performed using instrumented model piles installed in soft clay. During cyclic loading, the piles demonstrated a transition from stable to unstable behaviour when the applied loads reached a specific load threshold. Stable behaviour was defined when increments of plastic displacement decreased as the number of load cycles increased. During stable behaviour, radial effective stresses at the pile-soil interface remained constant. During unstable behaviour, pore pressures at the pile-soil interface rose as the number of cycles increased. This resulted in reduced radial effective stresses and progressively increasing displacement rates. Due to the presence of these excess pore pressures, the shaft resistance recorded during static load tests, performed after a period of unstable cyclic loading, were lower than those measured on piles where the pore pressure was fully equalised. However, the axial resistance was seen to be rate dependent. Fast loading of the pile resulted in reductions of pore water pressure at the soil-pile interface and enhanced shaft resistance which could overcome the negative effect caused by cyclic loading.

Undergraduate Research Models Applicable for Geotechnics

2013-02-20T12:27:49Z

Undergraduate Research Models Applicable for Geotechnics Laefer, Debra F. The projected, increasing gap between expected workforce staffing needs of those with science technology and engineering (STEM) training and the anticipated graduates with STEM degrees demands a re-examination of how to increase the number of STEM students graduating and remaining in STEM careers. Given the continued acute under-representation of women and some racial minorities, these groups warrant additional consideration, as their further engagement may help fill the shortfall. In debates and research surrounding these challenges, the issue of retention has received relatively little investigation both in terms of bachelor's level retention for degree completion and longer-term retention within STEM activities (either educational or industrial). Anecdotal information would indicate that undergraduate students engaged in research are more likely to complete their degrees, improve their grades after participation, enroll in STEM-based master's programs, and remain in STEM careers. This paper outlines various models for undergraduate engagement in geotechnical research, as a means to develop curricular and non-curricular, short- to medium-term opportunities to promote such efforts. Geo-Frontiers Congress 2011, Dallas, Texas, United States, March 13-16, 2011

Monitoring Bridge Dynamic Behaviour Using an Instrumented Two Axle Vehicle

2013-02-20T12:25:08Z

Monitoring Bridge Dynamic Behaviour Using an Instrumented Two Axle Vehicle McGetrick, P.; González, Arturo; O'Brien, Eugene J. Highway structures such as bridges are subject to continuous degradation primarily due to ageing, loading and environmental factors. A rational transport policy must monitor and provide adequate maintenance to this infrastructure to guarantee the required levels of transport service and safety. Increasingly in recent years, bridges are being instrumented and monitored on an ongoing basis due to the implementation of Bridge Management Systems. This is very effective and provides a high level of protection to the public and early warning if the bridge becomes unsafe. However, the process can be expensive and time consuming, requiring the installation of sensors and data acquisition electronics on the bridge. This paper investigates the use of an instrumented 2-axle vehicle fitted with accelerometers to monitor the dynamic behaviour of a bridge network in a simple and cost-effective manner. A simplified half car-beam interaction model is used to simulate the passage of a vehicle over a bridge. This investigation involves the frequency domain analysis of the axle accelerations as the vehicle crosses the bridge. The spectrum of the acceleration record contains noise, vehicle, bridge and road frequency components. Therefore, the bridge dynamic behaviour is monitored in simulations for both smooth and rough road surfaces. The vehicle mass and axle spacing are varied in simulations along with bridge structural damping in order to analyse the sensitivity of the vehicle accelerations to a change in bridge properties. These vehicle accelerations can be obtained for different periods of time and serve as a useful tool to monitor the variation of bridge frequency and damping with time. Bridge & Infrastructure Research in Ireland 2010 (BRI 10), Cork, 2-3 September 2010