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Data buoys are a widespread method of not only monitoring environmental parameters, but have a range of other applications: from surveillance to providing power for autonomous underwater vehicles (AUVs). The majority of data buoys currently in use are either solely powered by batteries, or they employ an array of solar panels to sporadically top up the battery power when environmental conditions are suitable. Less usual for data buoys is the use of wind power—though some successful hybrids of the two, such as the AXYS Technologies WindSentinel, also exist. As wave power technology matures, advancements in this currently underdeveloped technology could allow data buoys the option of using wave energy converters (WECs) as an alternative renewable power source. Data buoys could provide a small-scale application of WECs where many of the issues with harvesting such a stochastic and irregular energy source would be highlighted. The lessons learned in developing wave-powered data buoys could potentially be applied to larger, more costly wave energy applications such as wave farms or megawatt-level generators. This review considers data buoy projects currently in development—particularly those that look to incorporate a wave energy harvesting mechanism as either their primary or secondary power source, and their prospects, both as end-use applications in their own right, and as low-cost platforms to prove emerging wave energy technology for larger-scale use.

This paper presents a comprehensive review of boundary element methods for hydrodynamic modelling of wave energy systems. To design and optimise a wave energy converter (WEC), it is estimated that several million hours of WEC operation must be simulated. Linear boundary element methods are sufficiently fast to provide this volume of simulation and high speed of execution is one of the reasons why linear boundary element methods continue to underpin many, if not most, applied wave energy development efforts; however, the fidelity of the physics included is inadequate for some of the required design calculations. Judicious use of non-linear boundary element methods provides a route to increase the fidelity of the modeling while maintaining speed and other advantages over more computationally demanding alternatives such as Reynolds averaged Navier–Stokes (RANS) or smooth particle hydrodynamics (SPH). The paper presents some background to each aspect of the boundary methods reviewed, building up a relatively complete theoretical framework. Both linear and nonlinear methods are covered, and consideration is given to the computational complexity of the methods reviewed. The paper aims to provide a review that is useful in selection of the most appropriate techniques for the next generation of WEC design tools.

We propose in this White Paper a concept for a space experiment using cold atoms to search for ultra-light dark matter, and to detect gravitational waves in the frequency range between the most sensitive ranges of LISA and the terrestrial LIGO/Virgo/KAGRA/INDIGO experiments. This interdisciplinary experiment, called Atomic Experiment for Dark Matter and Gravity Exploration (AEDGE), will also complement other planned searches for dark matter, and exploit synergies with other gravitational wave detectors. We give examples of the extended range of sensitivity to ultra-light dark matter offered by AEDGE, and how its gravitational-wave measurements could explore the assembly of super-massive black holes, first-order phase transitions in the early universe and cosmic strings. AEDGE will be based upon technologies now being developed for terrestrial experiments using cold atoms, and will benefit from the space experience obtained with, e.g., LISA and cold atom experiments in microgravity. This paper is based on a submission (v1) in response to the Call for White Papers for the Voyage 2050 long-term plan in the ESA Science Programme. ESA limited the number of White Paper authors to 30. However, in this version (v2) we have welcomed as supporting authors participants in the Workshop on Atomic Experiments for Dark Matter and Gravity Exploration held at CERN: ({\tt https://indico.cern.ch/event/830432/}), as well as other interested scientists, and have incorporated additional material.

Wave energy devices are designed, and controlled, to be extremely responsive to incoming wave excitation, hence, maximising power absorption. Due to the consequent large motion excursions, highly nonlinear behaviour is likely to occur, especially in relation to variations in wetted surface. Moreover, nonlinearities may induce parametric instability, or activate internal mechanisms for exchanging energy between different degrees of freedom (DoFs), usually affecting the overall efficiency of the device. Consequently, single-DoF linear models may produce overly optimistic power production predictions, and neglect important dynamics of the system. One highly nonlinear phenomenon, potentially detrimental to power absorption for several wave energy converters, is parametric roll/pitch; due to parametric excitation, part of the energy flow is internally diverted, from the axis where the power take-off is installed, to a secondary axis, generating parasitic motion. This paper proposes a computationally efficient multi-DoF nonlinear model, which can effectively describe nonlinear behaviour, such as parametric pitch and roll, and their impact on motion prediction, power production assessment, and optimal control parameters.

Most wave energy converters (WECs) are described by linear mathematical models, based on the main assumption of small amplitudes of motion. Notwithstanding the computational convenience, linear models can become inaccurate when large motions occur. On the other hand, nonlinear models are often time consuming to simulate, while model-based controllers require system dynamic models which can execute in real time. Therefore, this paper proposes a computationally efficient representation of nonlinear static and dynamic Froude–Krylov forces, valid for any heaving axisymmetric point absorber. Nonlinearities are increased by nonuniform WEC cross sectional area and large displacements induced by energy maximising control strategies, which prevent the device from behaving as a wave follower. Results also show that the power production assessment realized through a linear model can be overly optimistic and control parameters calculations should also reflect the true nonlinear nature of the WEC model.

In order to increase the overall power production efficiency of wave energy technology in the face of sea state variability, the presence of the control is mandatory. A model of the system is required to tune the controller parameters and predict the resulting performances. Even though the relevance of nonlinearities is magnified by the presence of the controller, the device model employed is usually linear. An implementation of control in a fully nonlinear simulation model is desirable, but missing. Hence, this paper proposes to use the fully nonlinear computational fluid dynamics (CFD) environment, implementing the latching control strategy in the open source software OpenFOAM. A case study has been analyzed to highlight the nonlinear behavior of a device under latching control and to evaluate the differences between linear and nonlinear simulation models. The results show that the linear model overestimates the amplitude of motion, and, as a result, the extracted power. Moreover, the choice of the optimal control parameter is significantly affected by the nonlinear effect on the natural period of the device.

Yersiniosis associated with abdominal pain was commonly reported in Ireland in the 1980s. However, the Health Protection Surveillance Centre (HPSC) currently records only three to seven notified cases of yersiniosis per year. The most common cause of yersiniosis worldwide is Yersinia enterocolitica, and the leading source for this organism is consumption of pork-based food products. In contrast to the apparent current scarcity of yersiniosis cases in humans in Ireland, pathogenic Y. enterocolitica are detectable in a high percentages of pigs. To establish whether the small number of notifications of human disease was an underestimate due to lack of specific selective culture for Yersinia, we carried out a prospective culture study of faecal samples from outpatients with diarrhoea, with additional culture of throat swabs, appendix swabs and screening of human sewage. Pathogenic Yersinia strains were not isolated from 1,189 faeces samples, nor from 297 throat swabs, or 23 appendix swabs. This suggested that current low notification rates in Ireland are not due to the lack of specific Yersinia culture procedures. Molecular screening detected a wider variety of Y. enterocolitica-specific targets in pig slurry than in human sewage. A serological survey for antibodies against Yersinia YOP (Yersinia Outer Proteins) proteins in Irish blood donors found antibodies in 25 %, with an age-related trend to increased seropositivity, compatible with the hypothesis that yersiniosis may have been more prevalent in Ireland in the recent past.

We measured a suite of common biomarker responses for the first time in the Sydney rock oyster Saccostrea glomerata to evaluate their utility as biological effects measures for pollution monitoring. To examine the relationship between biomarker responses and population level effects, fertilisation and embryo development assays were also conducted. Adult oysters were deployed in two contaminated estuaries and a reference estuary in Sydney, Australia. The concentrations of various contaminants (metals and polycyclic aromatic hydrocarbon, PAHs) were quantified in oyster's tissue from each site and both metals and total PAHs were significantly elevated in contaminated estuaries relative to the reference estuary. Lysosomal membrane destabilisation, lipid peroxidation levels and glutathione (GSH) concentrations were measured in the digestive gland of oysters. Of all biomarkers measured, lysosomal membrane destabilisation proved to be the most useful indicator of oysters facing anthropogenic stress and we suggest this may be an especially useful biomarker for incorporation into local environmental monitoring pro- grams. Moreover, lysosomal membrane destabilisation showed good correlations with fertilisation, normal embryo development and estuary status. GSH and lipid peroxida- tion were not as valuable for distinguishing between estu- aries exposed to differing levels of anthropogenic stress, but did provide additional valuable information regarding overall health status of the oysters.

Nitrite represents a bioactive reservoir of nitric oxide (NO) that may modulate vasodilation, respiration and cytoprotection after ischemia-reperfusion injury. Although nitrite formation is thought to occur via reaction of NO with oxygen, this third-order reaction cannot compete kinetically with the reaction of NO with hemoglobin to form nitrate. Indeed, the formation of nitrite from NO in the blood is limited when plasma is substituted with physiological buffers, which suggests that plasma contains metal-based enzymatic pathways for nitrite synthesis. We therefore hypothesized that the multicopper oxidase, ceruloplasmin, could oxidize NO to NO+, with subsequent hydration to nitrite. Accordingly, plasma NO oxidase activity was decreased after ceruloplasmin immunodepletion, in ceruloplasmin knockout mice and in people with congenital aceruloplasminemia. Compared to controls, plasma nitrite concentrations were substantially reduced in ceruloplasmin knockout mice, which were more susceptible to liver infarction after ischemia and reperfusion. The extent of hepatocellular infarction normalized after nitrite repletion. These data suggest new functions for the multicopper oxidases in endocrine NO homeostasis and nitrite synthesis, and they support the hypothesis that physiological concentrations of nitrite contribute to hypoxic signaling and cytoprotection.

Gortyna borelii lunata is a rare species of moth with a widespread, but localised distribution in Europe. In Britain, the moth is restricted to coastal grassland habitats that support its larval foodplant (Peucedanum officinale), in the southeast of England.Threats to G. borelii lunata in Britain include inappropriate management and sea-level rise. This study investigates how to secure the future of the moth in Britain by managing existing colonies appropriately and determining whether translocations of the species, away from the dangers of flooding, would be feasible. A mowing experiment and a translocation trial were conducted. Results from the mowing experiment indicate that cutting annually in either August or November is detrimental to the abundance of the moth. It is recommended that where sites must be mown this be performed on rotation, leaving much of the site uncut each year. The translocation of the moth and its foodplant to a site away from the threats of flooding was very successful, demonstrating that the species establishes well and can survive on higher ground. It is concluded that to secure the future of the moth in Britain, a sustainable network of interconnected sites for the species should be created. Also, an appropriate management plan should be formulated for each site.

The South Carolina coastal zone is among the fastest growing areas in the U.S., and population epicenters are marked by dense brackish water pond (lagoon) coverage associated with housing complexes and golf courses. Surveillance efforts in 2001–2002 documented the widespread occurrence of several types of potentially or measurably toxic harmful algal blooms (HABs) in these ponds. These man-made retention ponds were constructed in order to serve as a buffer between developed areas and open estuaries or for aesthetic reasons. However, the combination of restricted tidal flow and nutrient and/or contaminant deposition creates a stimulatory environment for potential HAB formation. These discoveries introduce the need to consider mitigation measures to existing ponds and HAB preventive strategies for future pond construction.

A tandem deployment system was used to critically evaluate relationships between important water chemistry parameters (pH, salinity, dissolved oxygen) and biotic performance based on clam growth. The effects of environmental conditions on growth of juvenile clams,Mercenaria mercenaria, were determined after 7-day field deployments in cages at reference sites from 1998 to 2000. Continuous measurements of the overlying water chemistry parameters were monitored by deploying an in situ water quality instrument (Hydrolab Datasonde) at the same time. While salinity was identified as an important determinant of clam growth over wide salinity ranges (10–35‰), pH was also found to be a very important parameter, especially in low-salinity regimes (

This paper examines the application of artificial neural networks (ANNs) to the modelling and forecasting of electricity demand experienced by an electricity supplier. The data used in the application examples relates to the national electricity demand in the Republic of Ireland, generously supplied by the Electricity Supply Board (ESB). The paper focusses on three different time scales of interest to power boards: yearly (up to fifteen years in advance), weekly (up to three years in advance) and hourly (up to 24 h ahead). Electricity demand exhibits considerably different characteristics on these different time scales, both in terms of the underlying autoregressive processes and the causal inputs appropriate to each time scale. Where possible, the ANN-based models draw on the applications experience gained with linear modelling techniques and in one particular case, manual forecasting methods.

There are numerous potential environmental risks of engineered nanoparticles that are not yet well-characterized or understood. Nanoparticles may be introduced into aquatic environments during production processes and also as a result of release following their use in electronic and biological applications. The objectives of these studies were to characterize the behavior of quantum dots (QD) in water, and the accumulation of and toxicity to potential biological receptors in aquatic ecosystems. There are natural differences in environmental factors that may affect the degradation rates of QD’s as well as their toxicity, including temperature, salinity, and pH conditions. To assess the responses under different pH conditions, nonfunctionalized QD’s composed of a Cd/Se core surrounded by a ZnS shell (Evident Technologies) were added to distilled water, at pHs of 4, 6, and 8, and the changes in fluorescent emission spectra over time were determined. Likewise, to determine the effects of salinity on degradation rates, QD’s were added to 0.22 filtered seawater samples of different salinities (10, 20, and 30‰). The accumulation and potential toxicity of QD’s were evaluated using hepatopancreas cells of oysters, Crassostrea virginica.Fluorescent spectroscopy studies with water and cell samples indicated some degradation in low pH and high salinity waters, but did not indicate that there was increased degradation of QD’s accumulated in cells. Fluorescent confocal microscopy verified that QD’s were accumulated into the hepatopancreas cells. Transmission electron microscopy (TEM) studies verified cellular accumulation, and also indicated some limited degradation of the QD’s by the cells over the short time periods (e.g. hours) used in these preliminary studies. Using a lysosomal destabilization assay, there was some evidence of toxicity to hepatopancreatic cells. These kinds of basic studies are essential for characterizing potential cellular toxicity and addressing the potential impacts of nanoengineered particles on aquatic organisms and basic cellular responses.

CHROMIUM, vanadium and manganese are present in similar abundances in the Earth's mantle and the Moon, and are substantially depleted relative to their Mg-normalized primordial abundances1–6. Experimental studies7,8 of the partitioning of chromium, vanadium and manganese between molten iron and silicates show that these elements are lithophile at the pressures, temperatures and oxygen fugacities prevailing in the Earth's upper mantle and in the Moon. Here, we show that at much higher pressures, corresponding to those in the Earth's lower mantle, the partitioning behaviour of Cr, V and Mn changes owing to increasing solubility of oxygen in molten iron. Cr and V (and perhaps Mn) are preferentially partitioned into molten iron under these conditions. We therefore attribute the depletions of these elements in the Earth's mantle to their siderophile behaviour during formation of the Earth's core, at pressures that were sufficiently high to cause substantial amounts of oxygen to dissolve in molten metallic iron. Similar depletion patterns of Cr, V and Mn in the Earth's mantle and the Moon strongly suggest that a large proportion of the Moon was derived from the Earth's mantle after the Earth's core had segregated.

Embryos, four different ages of larvae, juveniles, and adults of an Hawaiian bivalve,Isognomon californicum, were exposed to a range of cadmium concentrations at two salinities to determine 48-hr LC50s and to compare the relative sensitivities of the various life stages. The Cd 48-hr LC50s of embryos, 3 day and 10 day old larvae were similar. Older larvae, 24 and 36 days, also showed a similar sensitivity to each other but their LC50s were approximately one order of magnitude higher than those of the younger stages. Newly settled juveniles were less sensitive than embryonic or larval stages and adults were the least sensitive. There was a general trend of increased toxicity with decreased salinity, but salinity effects were not significant with late larvae, juveniles, or adults.

A new high pressure phase with the composition Ca2AlSiO5.5 has been synthesized using an MA-8 apparatus operating at 1700° C and 16 GPa. The phase possesses a structure analagous to CaSiO3 perovskite but with half the Si atoms replaced by Al, and charge balance provided by vacancies in the oxygen sub-lattice. The unit cell possesses a lattice parameter, ao = 3.706 ± 0.003 A (room P and T value), based on a simple cubic perovskite structure. However, electron diffraction shows that a superstructure has developed parallel to one of the {111} cubic planes with a wavelength of 10.70 A (equals 5 × ¦d111¦), so that the Ca2AlSiO5.5 cell must be described formally as rhombohedral with a = 11.12 A and α = 27.27 degrees. This rhombohedral cell is metrically cubic, since the distortion of the cubic cell is not determinable from X-ray diffraction patterns obtained so far. The calculated density of this high pressure phase Ca2AlSiO5.5 is 3.64 gm·cm-3. This low density is related in part to the large proportion of oxygen vacancies present in the structure. Because of the low density, this phase is unlikely to be a significant mineralogical constituent of the lower mantle, unless the phase is characterized by extreme compressibility. However, the identification of the phase may be of significance in showing how A12O3 can be accommodated in silicate perovskite via replacement of SiVI in octahedral sites accompanied by production of one oxygen defect for every 2 Al atoms substituted. The possibility that this mode of substitution might be relevant to the incorporation of Al2O3 in MgSiO3 perovskite warrants further study.

The results of a reconnaissance investigation of melting relationships in the system Fe-FeO at 16 GPa were recently described by Kato and Ringwood (1989). The principal sources of uncertainties in those experiments were caused by loss of FeO to sample capsules during runs and the estimation of sample temperatures by an indirect method, based upon a prior calibration of the relationship between power input and temperature. A further set of 24 runs at 16 GPa has been carried out using improved experimental techniques. The melting temperatures of iron and wustite at 16 GPa are found to be 1945±20° C and 1875±25° C respectively. (Quoted errors do not include possible effects of pressure on thermocouple emf). The Fe-FeO eutectic is now located at 10±2 wt% FeO and 1670±20° C (previously 15.5±3 wt% FeO and 1700±25° C). The new determination of the depression of the melting point of iron by solution of FeO is 27.5° C/wt% FeO as compared to the previous value of 23° C/wt% FeO. The present results show that the contraction of the liquid immiscibility field in the system at high pressure is somewhat larger than was estimated previously. This study confirms the general topology of high pressure phase relationships in the Fe-FeO system obtained by Kato and Ringwood (1989) and has similar implications for the process of core formation within the Earth.