Timothy Sullivan

Antifouling performances of macro- to micro- to nano-copper materials for the inhibition of biofouling in its early stages

Copper has been known to possess antimicrobial properties since as far back as the Phoenician era where ship hulls were copper sheathed to prevent the inevitable effects of biofouling. As a consequence of evolving scientific research and development, the realisation of novel materials and agents has enabled new scientific branches - such as nanotechnology. In this paper we investigate the performance of different forms of copper (macro, micro and nano) for application as antifouling materials. Samples are deployed in SmartBay Ireland for four weeks and analysed for evidence of biofouling. It was found that copper in its nano form, produced the greatest antifouling effectiveness in both PDMS and sol-gel matrices.

A low-cost autonomous optical sensor for water quality monitoring.

A low-cost optical sensor for monitoring the aquatic environment is presented, with the construction and design described in detail. The autonomous optical sensor is devised to be environmentally robust, easily deployable and simple to operate. It consists of a multi-wavelength light source with two photodiode detectors capable of measuring the transmission and side-scattering of the light in the detector head. This enables the sensor to give qualitative data on the changes in the optical opacity of the water. Laboratory tests to confirm colour and turbidity-related responses are described and the results given. The autonomous sensor underwent field deployments in an estuarine environment, and the results presented here show the sensors capacity to detect changes in opacity and colour relating to potential pollution events. The application of this low-cost optical sensor is in the area of environmental pollution alerts to support a water monitoring programme, where multiple such sensors could be deployed as part of a network.

The characterization, replication and testing of dermal denticles of Scyliorhinus canicula for physical mechanisms of biofouling prevention

There is a current need to develop novel non-toxic antifouling materials. The mechanisms utilized by marine organisms to prevent fouling of external surfaces are of interest in this regard. Biomimicry of these mechanisms and the ability to transfer the antifouling characteristics of these surfaces to artificial surfaces are a highly attractive prospect to those developing antifouling technologies. In order to achieve this, the mechanisms responsible for any antifouling ability must be elucidated from the study of the natural organism and the critical surface parameters responsible for fouling reduction. Dermal denticles of members of the shark family have been speculated to possess some natural, as yet unidentified antifouling mechanism related to the physical presence of denticles. In this study, the dermal denticles of one particular member of the slow-swimming sharks, Scyliorhinus canicula were characterized and it was found that a significant natural variation in denticle dimensions exists in this species. The degree of denticle surface contamination was quantified on denticles at various locations and it was determined that the degree of contamination of the dorsal surface of denticles varies with the position on the shark body. In addition, we successfully produced synthetic sharkskin samples using the real skin as a template. Testing of the produced synthetic skin in field conditions resulted in significant differences in material attachment on surfaces exhibiting denticles of different dimensions.

Occurrence of Selected Metals in Wastewater Effluent and Surface Water in Ireland

ABSTRACT Metals occur naturally in the environment and as constituents of the Earth’s crust. They have many uses, and metals such as iron, copper, and zinc are widely used in industries. Elevated levels of metals in the environment also occur as a result of human activities (municipal, residential, and traffic–related activities). A list of 15 metals chosen for this study included priority substances and those listed in the European Union Water Framework Directive 2000/60/EC. The concentrations of heavy metals in the environment are affected by several factors that must be taken into account when monitoring heavy metals released into the environment through wastewater treatment plants (WWPTs). This work examines the concentrations of metals found in WWPTs and the effects of treatment type on dissolved metal concentrations. Effluent samples were collected from the outflow of nine WWPTs in Dublin and Cork, Ireland from July 2009 to June 2011. All samples were found to contain priority metals that exceeded environmental quality standards in several cases. We present the frequency of occurrence and concentrations of metals in effluents of studied WWPTs and discuss relationships between the occurrence of heavy metals, the influence of factors such as industrial inputs, levels of treatment at WWPTs, and percentage urban area in an agglomeration. The results of this study are an indication that WWPTs may be contributing to the high levels of heavy metals found at discharge points back into river systems.

Continuous high-frequency monitoring of estuarine water quality as a decision support tool a Dublin Port case study /

High-frequency, continuous monitoring using in situ sensors offers a comprehensive and improved insight into the temporal and spatial variability of any water body. In this paper, we describe a 7-month exploratory monitoring programme in Dublin Port, demonstrating the value of high-frequency data in enhancing knowledge of processes, informing discrete sampling, and ultimately increasing the efficiency of port and environmental management. Kruskal–Wallis and Mann–Whitney tests were used to show that shipping operating in Dublin Port has a small–medium effect on turbidity readings collected by in situ sensors. Turbidity events are largely related to vessel activity in Dublin Port, caused by re-suspension of sediments by vessel propulsion systems. The magnitudes of such events are strongly related to water level and tidal state at vessel arrival times. Crucially, measurements of Escherichia coli and enterococci contamination from discrete samples taken at key periods related to detected turbidity events were up to nine times higher after vessel arrival than prior to disturbance. Daily in situ turbidity patterns revealed time-dependent water quality “hot spots” during a 24-h period. We demonstrate conclusively that if representative environmental assessment of water quality is to be performed at such sites, sampling times, informed by continous monitoring data, should take into account these daily variations. This work outlines the potential of sensor technologies and continuous monitoring, to act as a decision support tool in both environmental and port management.

Configuration Management for Networked Reconfigurable Embedded Devices

Distribution of product updates to embedded devices can increase product lifetimes for consumers whilst increasing revenues and brand loyalty for vendors. Dynamic provisioning of application solutions to embedded devices are complex due to their heterogeneous nature. This paper proposes a configuration management architectural framework which incorporates a mobile agent based push methodology for networked reconfigurable embedded devices. FPGAs (Field Programmable Gate Arrays) are hardware components within embedded systems that can be dynamically reconfigured. Product updates are composed of both software and reconfigurable hardware code which can be tailored to the physical constraints of the device. Push technology is a distribution mechanism initiated by the vendor enabling delivery of product updates. The proposed infrastructure is built upon the solid foundations of agent-based design patterns. Agent technology provides an ideal environment for embedded systems management. Mobile agents completely encapsulate hardware-software based solutions providing a coherent abstraction for their distribution. The paper also outlines an initial demonstrator system.

Determination of spatial and temporal variability of pH and dissolved oxygen concentrations in a seasonally hypoxic semi-enclosed marine basin using continuous monitoring

Measurement and prediction of ocean acidification effects for nearshore marine ecosystems is currently a major objective of climate change research. This study examines the scales of pH variability in both surface waters (<10 m depth) and deeper waters associated with localised seasonal hypoxia over two years at Lough Hyne marine reserve, Cork, Ireland. Lough Hyne, a semi-enclosed marine system, experiences localised seasonal (approximately May to September each year) hypoxia and eventual anoxia below a depth of circa 25 m, due largely to its bathymetric profile. We report the relationships between pH and other environmental parameters such as dissolved oxygen (DO) and temperature at this location, and we provide data, obtained using continuous autonomous sensing technology, which demonstrates that the variability in pH measurements in the waters of Lough Hyne marine reserve are comparable to predictions of future ocean acidification. This is of interest as comparatively few directly measured time series of pH in marine waters are reported, and additionally the first pH measurements were reported from Lough Hyne over 6 decades ago in 1952. This work also measures for the first time the steep chemical gradients associated with the transition from anoxia to normoxia that result in profound pH changes at Lough Hyne, providing insight into natural variability in pH experienced by marine organisms at such locations.

Smart multi-modal marine monitoring via visual analysis and data fusion

Estuaries and coastal areas contain increasingly exploited resources that need to be monitored, managed and protected efficiently and effectively. This requires access to reliable and timely data and management decisions must be based on analysis of collected data to avoid or limit negative impacts. Visually supported multi-modal sensing and data fusion offer attractive possibilities for such arduous tasks. In this paper, we demonstrate how an in-situ sensor network can be enhanced with the use of contextual image data. We assimilate and alter a state-of-the-art background modelling technique from the image processing domain in order to detect turbidity spikes in water quality sensor measurements automatically. We then combine this with visual sensing to identify abnormal events that are not caused by local activities. The system can potentially assist those charged with monitoring large scale ecosystems, combining real-time analytics with improved efficiency and effectiveness.

Handheld medical devices negotiating for reconfigurable resources using agents

The nomadic nature of medical professionals can hinder their ability to access efficient medical tools at locations of their choice. The portability and connectivity characteristics of handheld medical devices can help resolve this issue. However, these handhelds have a physical size constraint inhibiting their system resource capacity. This limits their ability to support a wide range of medical applications effectively. Reconfigurable hardware incorporated within distributed servers has vast potential to improve the system performance and versatility of mobile medical devices. To fully realise the benefit of networked reconfigurable resources, portable computers need an effective middleware to enable them to efficiently utilise surrounding adaptive servers. Agent technology is a sophisticated and intelligent middleware framework that can empower handheld medical devices to exploit networked reconfigurable hardware resources. This paper outlines a deployment strategy that incorporates a high-level protocol to facilitate mobile device computational offloading. This protocol is based on efficient cooperation and negotiation between agents in a distributed medical environment. An experimental demonstrator system is shown and simulation results of the negotiation technique are presented.

Marine diatom settlement on microtextured materials in static field trials

Abstract The influence of surface topography (surface relief) on biofouling and cell settlement has been widely examined in the search for novel marine antifouling materials. Effects of surface topography on biofilms are, however, most commonly reported for laboratory experiments only. Marine diatoms are a particularly problematic group of biofouling organisms, and marine raphid diatom species are commonly used in conjunction with other assays to assess antifouling efficacy in laboratory studies. The effects of topographically structured materials on natural marine diatom fouling communities in field experiments are less commonly reported. Here, we report a number observations on the effects of microstructures created in poly(dimethylsiloxane) on diatom settlement in static field trials. It can be concluded that the effects of microscale surface topography on initial natural diatom settlement under static conditions in field tests depend upon the size, shape, adhesion strategy of the biofouling diatom species. Furthermore, while the topography of the underlying surface may influence the kinetics of cell settlement in laboratory tests, these effects can be masked by the effects of cell/mucilage aggregates and the diversity of settling cells in the natural marine environment.