Monitoring the condition of Marine Renewable Energy Devices through underwater acoustic emissions: Case study of a wave energy converter in Falmouth Bay, UK

Abstract Maintaining the engineering health of Marine Renewable Energy Devices (MREDs) is one of the main limits to their economic viability, because of the requirement for costly marine interventions in challenging conditions. Acoustic Emission (AE) condition monitoring is routinely and successfully used for land-based devices, and this paper shows how it can be used underwater. We review the acoustic signatures expected from operation and likely failure modes of MREDs, providing a basis for a generic classification system. This is illustrated with a Wave Energy Converter tested at Falmouth Bay (UK), monitored for 2 years. Underwater noise levels have been measured between 10 Hz and 32 kHz throughout this time, covering operational and inactive periods. Broadband MRED contributions to ambient noise are generally negligible. Time-frequency analyses are used to detect acoustic signatures (60 Hz–5 kHz) of specific operational activities, such as the active Power Take Off, and relate them to engineering and environmental conditions. These first results demonstrate the feasibility of using underwater Acoustic Emissions to monitor the health and performance of MREDs.JW is funded by the Natural Environment Research Council (NERC grant NE/L002434/1) as part of the GW4+ Doctoral Training Partnership (http://www.nercgw4plus.ac.uk/). IB is funded through the SuperGen UK Centre for Marine Energy Research (EPSRC grant EP/M014738/1). The authors would also like to thank M.J. Witt (U. Exeter) for his invaluable assistance with acoustic data collection [14] and [15], funded by ESF, PRIMaRE, MERiFIC, TSB and Fred Olsen Renewables

Structure function of the UV variability of Q0957+561

We present a detailed structure function analysis of the UV variability of Q0957+561. From new optical observations, we constructed normalized structure functions of the quasar luminosity at restframe wavelengths of 2100 and 2600 \AA. Old optical records also allow the structure function to be obtained at 2100 \AA, but 10 years ago in the observer's frame. These three structure functions are then compared to predictions of both simple and relatively sophisticated (incorporating two independent variable components) Poissonian models. We do not find clear evidence of a chromatic mechanism of variability. From the recent data, 100-d time-symmetric and 170-d time-asymmetric flares are produced at both restframe wavelengths. Taking into account measurements of time delays and the existence of an EUV/radio jet, reverberation is probably the main mechanism of variability. Thus, two types of EUV/X-ray fluctuations would be generated within or close to the jet and later reprocessed by the disc gas in the two emission rings. The 100-d time-symmetric shots are also responsible for most of the 2100 \AA variability detected in the old experiment. However, there is no evidence of asymmetric shots in the old UV variability. If reverberation is the involved mechanism of variability, this could mean an intermittent production of high-energy asymmetric fluctuations. The old records are also consistent with the presence of very short-lifetime (10 d) symmetric flares, which may represent additional evidence of time evolution. We also discuss the quasar structure that emerges from the variability scenario.Comment: 7 pages, 4 figures. Accepted for publication in A&A (based on the brightness records at http://arxiv.org/abs/0810.4619

Acoustic life cycle assessment of offshore renewables – implications from a Wave-Energy Converter deployment in Falmouth Bay, UK

Marine Renewable Energy is developing fast, with hundreds of prototypes andoperational devices worldwide. Two main challenges are assessing their environmental impacts (especially in near-shore, shallow environments) and ensuring efficient and effective maintenance (requiring specialised ships and fair-weather windows), compounded by the lack of long-term measurements of full-scale devices. We present here broadband measurements (10 Hz to 32/48 kHz) acquired at the Falmouth Bay Test site (FaBTest, UK) from 2010 onwards, for a 16-m ring-shaped Wave Energy Converter, in waters up to 45 m deep. This period covers baseline measurements, including shipping from the neighbouringEnglish Channel, one of the busiest shipping lanes in the world (ca. 45,000 ship transits annually) and the full period of installation and energy production, including maintenance episodes. Acoustic signatures are measured as Sound Pressure Levels (e.g. for impacts) and time/frequency variations (for condition-based monitoring via Acoustic Emissions). They change through time, depending on weather and modes of operation. Long-term measurements are compared with modelling of potential variations in this complex environment and with laboratory experiments. These are used to outline the varying acoustic contributions through the life cycle of a typical wave energy converter, yieldinginsights for other wave devices in other environments

Extracellular Hsp72 concentration relates to a minimum endogenous criteria during acute exercise-heat exposure

Extracellular heat-shock protein 72 (eHsp72) concentration increases during exercise-heat stress when conditions elicit physiological strain. Differences in severity of environmental and exercise stimuli have elicited varied response to stress. The present study aimed to quantify the extent of increased eHsp72 with increased exogenous heat stress, and determine related endogenous markers of strain in an exercise-heat model. Ten males cycled for 90 min at 50% O2peak in three conditions (TEMP, 20°C/63% RH; HOT, 30.2°C/51%RH; VHOT, 40.0°C/37%RH). Plasma was analysed for eHsp72 pre, immediately post and 24-h post each trial utilising a commercially available ELISA. Increased eHsp72 concentration was observed post VHOT trial (+172.4%) (P<0.05), but not TEMP (-1.9%) or HOT (+25.7%) conditions. eHsp72 returned to baseline values within 24hrs in all conditions. Changes were observed in rectal temperature (Trec), rate of Trec increase, area under the curve for Trec of 38.5°C and 39.0°C, duration Trec ≥ 38.5°C and ≥ 39.0°C, and change in muscle temperature, between VHOT, and TEMP and HOT, but not between TEMP and HOT. Each condition also elicited significantly increasing physiological strain, described by sweat rate, heart rate, physiological strain index, rating of perceived exertion and thermal sensation. Stepwise multiple regression reported rate of Trec increase and change in Trec to be predictors of increased eHsp72 concentration. Data suggests eHsp72 concentration increases once systemic temperature and sympathetic activity exceeds a minimum endogenous criteria elicited during VHOT conditions and is likely to be modulated by large, rapid changes in core temperature

Endoscopic ultrasonography-identified celiac adenopathy remains a poor prognostic factor despite preoperative chemoradiotherapy in esophageal adenocarcinoma

ObjectiveWe reviewed our experience with preoperative chemoradiotherapy in patients with adenocarcinoma of the distal esophagus and pretreatment endoscopic ultrasonography-identified celiac adenopathy.MethodsOne hundred eighty-six patients with adenocarcinoma of the distal esophagus were staged with endoscopic ultrasonography before treatment from 1997 through 2004. All patients were treated with concurrent chemoradiotherapy (CRT group) and surgical intervention or induction chemotherapy followed by concurrent chemoradiotherapy (C→CRT group) and surgical intervention. Survival analysis (excluding operative mortality) evaluated various pretreatment factors.ResultsMultivariable Cox regression analysis showed that pretreatment endoscopic ultrasonography-identified celiac adenopathy was a significant predictor of decreased long-term survival (P = .03). Median and 3-year survivals were 49 months and 54% in the endoscopic ultrasonography-identified cN0 M0 group (n = 65), 45 months and 56% in the endoscopic ultrasonography-identified cN1 M0 group (n = 96), and 19 months and 12% in the endoscopic ultrasonography-identified celiac adenopathy (cM1a) group (n = 18; P = .03). Increased systemic relapse was noted in the endoscopic ultrasonography-identified cM1a group (44% vs 22%, P = .07). The only factor associated with increased survival in the endoscopic ultrasonography-identified cM1a group (27 vs 15 months, P = .02) was the addition of induction chemotherapy before concurrent chemoradiotherapy and surgical intervention.ConclusionsEndoscopic ultrasonography-identified celiac adenopathy in patients with adenocarcinoma of the distal esophagus conveys a poor prognosis despite preoperative chemoradiotherapy. These patients should be stratified in future multimodality trials. The investigation of induction chemotherapy before concurrent chemoradiotherapy might be warranted in this high-risk group of patients

The BSR-PsA:study protocol for the British Society for Rheumatology psoriatic arthritis register

Acknowledgements We acknowledge contribution of BSR-PsA study staff, under the supervision of KFK: Maureen Heddle, Barry Morris, Jonathan Lock and Jane Brady. We also acknowledge the support from the Centre for Healthcare Randomised Trials (CHaRT) at the University of Aberdeen, especially Mark Forrest and Brian Taylor, for database and IT support. We would like to thank Professor Iain McInnes from the University of Glasgow, and our International Advisory Committee (Professors Merete Hetland, Oliver Fitzgerald and Philip Mease), for their comments when developing the protocol and for advice in harmonising data collection with other international studies, and the staff at the British Society for Rheumatology, in particular Alan Roach, Ross Matthews, Chris Hiley and Debbie MacDonald. Finally, we are indebted to the staff at all participating NHS trusts (details of which are available from www.abdn.ac.uk/bsr-psa) and especially the NIHR Clinical Research Network research nurses for their assistance with participant recruitment and data collection. Funding The BSR-PsA is funded by the BSR as part of its rheumatology registers portfolio and, in turn, receives funding for this from pharmaceutical companies. At the time of publication, only Amgen (previously Celgene) have contributed to the funding of the BSR-PsA. Pharmaceutical companies providing funds to BSR do not participant in the conduct or oversight of the study. However, they do receive advance notice of publications on which they are able to comment. Companies contributing to the funding of the register can request anonymised data on clinically confirmed serious adverse events and some events of special interest (e.g. pregnancy) among participants prescribed the specific bDMARD or tsDMARD agents that they manufacture. Other than this information, they do not have access to any raw data. They may, however, request specific analyses to be performed, for which a pre-specific analysis plan is discussed, and additional funds are provided.Peer reviewedPublisher PD

Beyond the black box: promoting mathematical collaborations for elucidating interactions in soil ecology

This work is licensed under a Creative Commons Attribution 4.0 International License.Understanding soil systems is critical because they form the structural and nutritional foundation for plants and thus every terrestrial habitat and agricultural system. In this paper, we encourage increased use of mathematical models to drive forward understanding of interactions in soil ecological systems. We discuss several distinctive features of soil ecosystems and empirical studies of them. We explore some perceptions that have previously deterred more extensive use of models in soil ecology and some advances that have already been made using models to elucidate soil ecological interactions. We provide examples where mathematical models have been used to test the plausibility of hypothesized mechanisms, to explore systems where experimental manipulations are currently impossible, or to determine the most important variables to measure in experimental and natural systems. To aid in the development of theory in this field, we present a table describing major soil ecology topics, the theory previously used, and providing key terms for theoretical approaches that could potentially address them. We then provide examples from the table that may either contribute to important incremental developments in soil science or potentially revolutionize our understanding of plant–soil systems. We challenge scientists and mathematicians to push theoretical explorations in soil systems further and highlight three major areas for the development of mathematical models in soil ecology: theory spanning scales and ecological hierarchies, processes, and evolution

Beyond the black box: Promoting mathematical collaborations for elucidating interactions in soil ecology

© 2019 The Authors. Understanding soil systems is critical because they form the structural and nutritional foundation for plants and thus every terrestrial habitat and agricultural system. In this paper, we encourage increased use of mathematical models to drive forward understanding of interactions in soil ecological systems. We discuss several distinctive features of soil ecosystems and empirical studies of them. We explore some perceptions that have previously deterred more extensive use of models in soil ecology and some advances that have already been made using models to elucidate soil ecological interactions. We provide examples where mathematical models have been used to test the plausibility of hypothesized mechanisms, to explore systems where experimental manipulations are currently impossible, or to determine the most important variables to measure in experimental and natural systems. To aid in the development of theory in this field, we present a table describing major soil ecology topics, the theory previously used, and providing key terms for theoretical approaches that could potentially address them. We then provide examples from the table that may either contribute to important incremental developments in soil science or potentially revolutionize our understanding of plant-soil systems. We challenge scientists and mathematicians to push theoretical explorations in soil systems further and highlight three major areas for the development of mathematical models in soil ecology: Theory spanning scales and ecological hierarchies, processes, and evolution

LSST: from Science Drivers to Reference Design and Anticipated Data Products

(Abridged) We describe here the most ambitious survey currently planned in the optical, the Large Synoptic Survey Telescope (LSST). A vast array of science will be enabled by a single wide-deep-fast sky survey, and LSST will have unique survey capability in the faint time domain. The LSST design is driven by four main science themes: probing dark energy and dark matter, taking an inventory of the Solar System, exploring the transient optical sky, and mapping the Milky Way. LSST will be a wide-field ground-based system sited at Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m effective) primary mirror, a 9.6 deg$^2$ field of view, and a 3.2 Gigapixel camera. The standard observing sequence will consist of pairs of 15-second exposures in a given field, with two such visits in each pointing in a given night. With these repeats, the LSST system is capable of imaging about 10,000 square degrees of sky in a single filter in three nights. The typical 5$\sigma$ point-source depth in a single visit in $r$ will be $\sim 24.5$ (AB). The project is in the construction phase and will begin regular survey operations by 2022. The survey area will be contained within 30,000 deg$^2$ with $\delta<+34.5^\circ$, and will be imaged multiple times in six bands, $ugrizy$, covering the wavelength range 320--1050 nm. About 90\% of the observing time will be devoted to a deep-wide-fast survey mode which will uniformly observe a 18,000 deg$^2$ region about 800 times (summed over all six bands) during the anticipated 10 years of operations, and yield a coadded map to $r\sim27.5$. The remaining 10\% of the observing time will be allocated to projects such as a Very Deep and Fast time domain survey. The goal is to make LSST data products, including a relational database of about 32 trillion observations of 40 billion objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures available from https://www.lsst.org/overvie

Prenatal Diagnosis of Oculocutaneous Albinism by Electron Microscopy of Fetal Skin

Oculocutaneous albinism was diagnosed prenatally by electron microscopic examination of fetal skin samples taken during fetoscopy at 20 weeks of gestation. Melanosome development in hair bulb melanocytes progressed no further than stage II, indicating a lack of melanin synthesis. In 4 age-matched control fetuses, numerous stage IV melanosomes, signifying active melanin synthesis, were identified. The diagnosis was confirmed after the pregnancy was terminated at 22 weeks. Examination of the fetal eye showed absence of pigment in the retinal epithelium and uvea at a stage when ocular melanogenesis would normally be active. This study shows that oculocutaneous albinism can be detected in the second trimester using similar techniques to those employed in the prenatal diagnosis of epidermolysis bullosa and ichthyosis