55 research outputs found
Reliability assessment and criticality analysis for Wave Energy Converters
This paper applies existing
reliability methods, namely Reliability Block diagrams, to a notional wave energy converter configuration. It shows possible source of information and difficulties associated with an omnipresent lack of failure rate data.The reliability of wave energy converters (WECs) is a key issue that has to be addressed in order to make them a viable energy option. At this stage of early
industrial development the reliability assessment of WECs is a challenging task. In this paper existing reliability methods, namely Reliability Block diagrams,
have been applied to a notional configuration. It was found that omnipresent lack of failure rate data makes rather crude adjustments of often generic data necessary which generally lead to rather unfavourable
and highly uncertain results. Reliability data is either not available due to sparse field experience or is kept confidential, within different project developments to
secure competitive advantages and intellectual property.
In order to foster the progress of the marine energy industry, the reliability of devices must be demonstrated and improved. This requires a joint effort between industry stakeholders to collect, share and
disseminate existing failure knowledge and future operational experience.Engineering and Physical
Sciences Research Council (EPSRC) under the
SUPERGEN Marine Doctoral Programm
Is it a showstopper? Reliability assessment and criticality analysis for Wave Energy Converters
The reliability of wave energy converters (WECs) is a key issue that has to be addressed in order to make them a viable energy option. At this stage of early industrial development the reliability assessment of WECs is a challenging task. In this paper existing reliability methods, namely Reliability Block diagrams, have been applied to a notional configuration. It was found that omnipresent lack of failure rate data makes rather crude adjustments of often generic data necessary which generally lead to rather unfavourable and highly uncertain results. Reliability data is either not available due to sparse field experience or is kept confidential, within different project developments to secure competitive advantages and intellectual property. In order to foster the progress of the marine energy industry, the reliability of devices must be demonstrated and improved. This requires a joint effort between industry stakeholders to collect, share and disseminate existing failure knowledge and future operational experience
Class III PI-3-kinase activates phospholipase D in an amino acidâsensing mTORC1 pathway
In response to amino acid availability, the class III PI-3-kinase hVps34 activates the phospholipase PLD and mTORC1 signaling to regulate mammalian cell size
Long-lasting effects of land use history on soil fungal communities in second-growth tropical rain forests
Our understanding of the long-lasting effects of human land use on soil fungal communities in tropical forests is limited. Yet, over 70% of all remaining tropical forests are growing in former agricultural or logged areas. We investigated the relationship among land use history, biotic and abiotic factors, and soil fungal community composition and diversity in a second-growth tropical forest in Puerto Rico. We coupled high-throughput DNA sequencing with tree community and environmental data to determine whether land use history had an effect on soil fungal community descriptors. We also investigated the biotic and abiotic factors that underlie such differences and asked whether the relative importance of biotic (tree diversity, basal tree area, and litterfall biomass) and abiotic (soil type, pH, iron, and total carbon, water flow, and canopy openness) factors in structuring soil fungal communities differed according to land use history. We demonstrated long-lasting effects of land use history on soil fungal communities. At our research site, most of the explained variation in soil fungal composition (R2 = 18.6%), richness (R2 = 11.4%), and evenness (R2 = 10%) was associated with edaphic factors. Areas previously subject to both logging and farming had a soil fungal community with lower beta diversity and greater evenness of fungal operational taxonomic units (OTUs) than areas subject to light logging. Yet, fungal richness was similar between the two areas of historical land use. Together, these results suggest that fungal communities in disturbed areas are more homogeneous and diverse than in areas subject to light logging. Edaphic factors were the most strongly correlated with soil fungal composition, especially in areas subject to light logging, where soils are more heterogenous. High functional tree diversity in areas subject to both logging and farming led to stronger correlations between biotic factors and fungal composition than in areas subject to light logging. In contrast, fungal richness and evenness were more strongly correlated with biotic factors in areas of light logging, suggesting that these metrics might reflect long-term associations in old-growth forests. The large amount of unexplained variance in fungal composition suggests that these communities are structured by both stochastic and niche assemblage processes
Exploring the experience of fatigue in people with Charcot-Marie-Tooth disease
This qualitative study explored the phenomenon of fatigue for people with CharcotâMarieâTooth disease, while acknowledging the triggers, impact and strategies people have developed to manage this symptom in daily life. A phenomenological approach was used to explore the experience of fatigue. Participants were recruited from a support group. Twenty-five people participated in three focus
groups. Group interviews were tape recorded and independently transcribed. Transcripts were coded and emerging themes were highlighted. Four areas were explored and themes identified within them. Fatigue descriptions: energy depletion, overwhelming nature, variations in fatigue and fatigue as an abnormal experience; triggers of fatigue: activity, stress and mental concentration; impact of fatigue on: physical abilities, mood, guilt and frustration, isolation and concerns about how they were perceived by others; strategies to manage fatigue: coping with symptoms; planning ahead; deception; and reducing symptoms. This study revealed that fatigue is an overwhelming experience for people with CharcotâMarieâTooth disease that impacts on many areas of their lives. People may require significant adjustment that could be facilitated by fatigue management approaches. In addition, exercise may have potential to reduce the symptoms of fatigue in some people
The Bruton tyrosine kinase inhibitor ibrutinib with chemoimmunotherapy in patients with chronic lymphocytic leukemia
The safety and efficacy of ibrutinib, an oral inhibitor of Bruton tyrosine kinase, were evaluated with chemoimmunotherapy (CIT) in a multicenter phase 1b study. Patients with relapsed/refractory chronic lymphocytic leukemia received bendamustine and rituximab (BR) or fludarabine, cyclophosphamide, and rituximab (FCR) for up to 6 cycles with daily ibrutinib (420 mg) until progressive disease or unacceptable toxicity. Enrollment to FCR-ibrutinib closed early due to a lack of fludarabine-naive previously treated patients. No patients treated with BR-ibrutinib (n = 30) or FCR-ibrutinib (n = 3) experienced prolonged hematologic toxicity in cycle 1 (primary end point). Tolerability was as expected with either CIT or single-agent ibrutinib. The overall response rate (ORR) with BR-ibrutinib was 93.3%, including 16.7% complete responses (CRs) initially, which increased to 40% with the extension period. Including 1 patient with partial response with lymphocytosis, the best ORR was 96.7%. Sixteen of 21 patients with baseline cytopenias had sustained hematologic improvement. At 12 and 36 months, 86.3% and 70.3% remained progression-free, respectively. All 3 patients treated with ibrutinib-FCR achieved CR. Ibrutinib may enhance CIT efficacy without additive toxicities, providing the rationale for studying this combination in an ongoing phase 3 trial
Sea trials
A set of trials in an uncontrolled ocean environment that build conïŹdence in the functionality, maintenance, operation and performance of the device and its ability to survive extreme conditions
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