On the Analysis of a Wave Energy Farm with Focus on Maintenance Operations

Wave energy has a promising technical potential that could contribute to the future energy mix. However, costs related to the deployment of wave energy converters (WECs) are still high compared to other technologies. In order to reduce these costs, two principle options are available, a reduction in cost and an increase in productivity. This paper presents a reliability-based computational tool to identify typical decision problems and to shed light on the complexity of optimising a wave power farm. The proposed tool is used to investigate productivity and availability of a wave energy farm during 10 years of operational life. A number of optimization possibilities to improve productivity, namely vessel choice, maintenance regime, failure rate and component redundancy, are then explored in order to assess their effectiveness. The paper quantifies the yield increase and provides a practical approach to evaluate the effectiveness of strategic and operational decision options. Results, in terms of the variations in productivity and availability of the farm, are analysed and discussed. Conclusions highlight the importance of reliability-centred simulations that consider the specific decision parameters throughout the operational life to find suitable solutions that increase the productivity and reduce the running cost for offshore farms.The work in this paper has been conducted within the multinational Initial Training Network (ITN) OceaNET, funded under the PEOPLE Programme (Marie Curie Actions) of European Union’s FP7. Mojo Maritime have provided access to Mermaid to support, and for integration with, this research

Pregnant women's beliefs, expectations and experiences of antenatal ultrasound in Northern Tanzania

This qualitative study explored pregnant women's beliefs, expectations and experiences of the recently introduced antenatal ultrasound service in BomaNg'ombe hospital, Tanzania. Thematic analysis of 25 semi-structured interviews and 41 questionnaires was employed. The majority of women desired ultrasonography despite many not understanding the procedure or purpose. Patient's expectations included discovering fetal position, fetal sex and pregnancy problems. However, women frequently over-estimated the capacity of ultrasound, and had significant fears of harm. One sixth of questionnaire respondents said they did not want ultrasonography. Nonetheless since the service was introduced no woman has declined, and numerous interviewees believed scans were obligatory. Despite fears, some women reported enjoyment of ultrasound. Interviewees believed ultrasound would increase antenatal care (ANC) attendance. An informed consent policy and an education campaign are needed to reduce fears and maximiseuptake and health gains. The effects of ultrasound availability on timely ANC uptake, including amongst women not currently accessing ANC, should be further researche

A decision support model to optimise the operation and maintenance strategies of an offshore renewable energy farm

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.In order to accelerate the access into the energy market for ocean renewables, the operation and maintenance (O & M) costs for these technologies must be reduced. In this paper a reliability-based simulation tool for the optimization of the management of an offshore renewable energy (ORE) farm is presented. The proposed tool takes into account the reliability data of the simulated devices and estimations on the energy produced to create a series of results in terms of availability and maintainability of the farm. The information produced supports operational and strategic decision making regarding the O & M for offshore farms. A case study simulating a conceptual tidal energy project, consisting of an array of two tidal turbines located off the north coast of Scotland, is presented to show some of the results achievable with this model. The proposed methodology, although ado pted for a tidal farm here, is generally applicable to other kinds of ORE farms.This research has been conducted within the multinational Initial Training Network (ITN) OceaNET, funded under the People Programme (Marie Curie Actions) of the European Union's Seventh Framework ProgrammeFP7/2007-2013/under REA grant agreement no 607656. Mojo Maritime have provided access to Mermaid to support, and for integration with, this research

Failure and reliability growth in tidal stream turbine deployments

This is the author accepted manuscript. The final version is available from EWTEC via the link in this recordMany technical challenges have been ad dressed since the first commercial deployment of a tidal stream turbine in 2003. However, the technology is not yet competitive with other renewable energy generation in cost of energy terms, and there remains a reluctance among investors due to the perceived risk of device failure. In this work we reviewed and categorised all available tidal stream energy deployment reliability data. 57 deployments were identified to August 2020, encompassing a range of manufacturers, locations, device types and foundation systems. Each deployment was classified by device type, rated power, number of devices, grid connection, foundation type and location, then identified as either successful, under performing, curtailed or failed based on defined targets or availability. We found that 18% of deployments failed, 10% were withdrawn from service earlier than intended, and 10% generated less power than was planned. The most common cause of failure was blade failure, followed by generator and monitoring failures. After initial successful prototypes, failure rate increased between 2006 and 2011, possibly due to increased deploy ments at high flow rate sites. Subsequent deployments at lower flow rate sites led to a reduction in failure rate to 2018, and current failure rates remain relatively low in spite of a return to higher flow rate sites, suggesting that the sector is now benefiting from lessons learned in pervious failures.European Regional Development Fund (ERDF

Comparative Life Cycle Assessment of tidal stream turbine blades

This is the author accepted manuscript. The final version is available from EWTEC via the link in this recordRenewable energy allows electricity generation with lower environmental and resource impact than generation from fossil fuels. However, the manufacture, use and ultimate disposal of the equipment used to capture renewable energy has an environmental impact. This impact should be minimised. Most tidal turbine blades are currently manufactured from glass or carbon fibre reinforced polymers. Such blades cannot be recycled at the end of their life, and are disposed of in landfill or by incineration. As the tidal energy industry grows, the volume of non-recyclable waste is a potential problem. Here we consider the environmental impact of ten combinations of material and disposal method for tidal stream turbine blades, including recyclable options. Our findings suggest that: * Glass fibre blades have greenhouse gas emissions of around 15,500 kgCO2e for the scope considered, and a significant environmental impact in all impact categories. * Steel blades are heavy and have greater material and manufacturing greenhouse gas emissions than glass fibre blades, but these are partly offset by recycling. * Carbon fibre blades have the greatest impact of the cases considered in greenhouse gas, human toxicity, and marine toxicity. The impact is particularly large when disposed of in landfill. * Composite materials using flax fibre and recyclable resin may have lower impact (26% lower greenhouse gas emissions than glass fibre), provided they are treated correctly after use. These materials may also offer the potential for lower cost blades in future.European Regional Development Fund (ERDF

Dependence on Dectin-1 Varies With Multiple Candida Species

This is the final version. Available from Frontiers Media via the DOI in this recordFour Candida spp. (albicans, glabrata, tropicalis, parapsilosis) cause >95% of invasive Candida infections. C. albicans elicits immune responses via pathogen recognition receptors including C-type lectin-like receptors (CLRs). The CLR, Dectin-1 is important for host immunity to C. albicans and C. glabrata, however, whether Dectin-1 is important for host defense against C. tropicalis or C. parapsilosis is unknown. Therefore, we compared the involvement of Dectin-1 in response to these four diverse Candida spp. We found that Dectin-1 mediates innate cytokine responses to these Candida spp. in a species- and cell-dependent manner. Dectin-1 KO mice succumbed to infection with highly virulent C. albicans while they mostly survived infection with less virulent Candida spp. However, Dectin-1 KO mice displayed increased fungal burden following infection with each Candida spp. Additionally, T cells from Dectin-1 KO mice displayed enhanced effector functions likely due to the inability of Dectin-1 KO mice to clear the infections. Together, these data indicate that Dectin-1 is important for host defense to multiple Candida spp., although the specific roles for Dectin-1 varies with different Candida spp.Wellcome TrustRoyal SocietyUK Dementia Research InstituteMRC Centre for Medical Mycolog

Modulation of DNA topoisomerase II activity and expression in melanoma cells with acquired drug resistance

The role of DNA topoisomerases (Topo) IIα and IIβ was investigated in various drug-resistant melanoma cells. Melanoma cells resistant to etoposide, exhibited an up to tenfold reduced Topo II activity corresponding to an increasing degree of drug resistance indicating that modulation of Topo II activity contribute to the drug-resistant phenotype. The reduction of Topo II activity was reflected by decreased nuclear amounts of both Topo II isoforms. © 2000 Cancer Research Campaig

Programmed Iteration Controls the Assembly of the Nonanoic Acid Side Chain of the Antibiotic Mupirocin

\ua9 2022 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH. Mupirocin is a clinically important antibiotic produced by Pseudomonas fluorescens NCIMB 10586 that is assembled by a complex trans-AT polyketide synthase. The polyketide fragment, monic acid, is esterified by a 9-hydroxynonanoic acid (9HN) side chain which is essential for biological activity. The ester side chain assembly is initialised from a 3-hydroxypropionate (3HP) starter unit attached to the acyl carrier protein (ACP) MacpD, but the fate of this species is unknown. Herein we report the application of NMR spectroscopy, mass spectrometry, chemical probes and in vitro assays to establish the remaining steps of 9HN biosynthesis. These investigations reveal a complex interplay between a novel iterative or “stuttering” KS-AT didomain (MmpF), the multidomain module MmpB and multiple ACPs. This work has important implications for understanding the late-stage biosynthetic steps of mupirocin and will be important for future engineering of related trans-AT biosynthetic pathways (e.g. thiomarinol)