1,237 research outputs found
Numerical study on active and passive trailing edge morphing applied to a multi-MW wind turbine section
A progressive increasing in turbine dimension has characterized the technological development in offshore wind energy utilization. This aspect reflects on the growing in blade length and weight. For very large turbines, the standard control systems may not be optimal to give the best performance and the best vibratory load damping, keeping the condition of maximum energy production. For this reason, some new solutions have been proposed in research. One of these is the possibility of morphs the blade surface in an active way (increasing the performance in low wind region) or passive (load reduction) way.
In this work, we present a numerical study on the active and passive trailing edge morphing, applied to large wind turbines. In particular, the study focuses on the aerodynamic response of a midspan blade section, in terms of fluid structure interaction (FSI) and driven surface deformation.
We test the active system in a simple start-up procedure and the passive system in a power production with turbulent wind conditions, that is, two situations in which we expect these systems could improve the performance.
All the computations are carried out with a FSI code, which couples a 2D-CFD solver, a moving mesh solver (both implemented in OpenFOAM library) and a FEM solver.
We evaluate all the boundary conditions to apply in the section problem by simulating the 5MW NREL wind turbine with the NREL CAE-tools developed for wind turbine simulation
Measuring entanglement entropy through the interference of quantum many-body twins
Entanglement is one of the most intriguing features of quantum mechanics. It
describes non-local correlations between quantum objects, and is at the heart
of quantum information sciences. Entanglement is rapidly gaining prominence in
diverse fields ranging from condensed matter to quantum gravity. Despite this
generality, measuring entanglement remains challenging. This is especially true
in systems of interacting delocalized particles, for which a direct
experimental measurement of spatial entanglement has been elusive. Here, we
measure entanglement in such a system of itinerant particles using quantum
interference of many-body twins. Leveraging our single-site resolved control of
ultra-cold bosonic atoms in optical lattices, we prepare and interfere two
identical copies of a many-body state. This enables us to directly measure
quantum purity, Renyi entanglement entropy, and mutual information. These
experiments pave the way for using entanglement to characterize quantum phases
and dynamics of strongly-correlated many-body systems.Comment: 14 pages, 12 figures (6 in the main text, 6 in supplementary
material
Strongly Correlated Quantum Walks in Optical Lattices
Full control over the dynamics of interacting, indistinguishable quantum
particles is an important prerequisite for the experimental study of strongly
correlated quantum matter and the implementation of high-fidelity quantum
information processing. Here we demonstrate such control over the quantum walk
- the quantum mechanical analogue of the classical random walk - in the strong
interaction regime. Using interacting bosonic atoms in an optical lattice, we
directly observe fundamental effects such as the emergence of correlations in
two-particle quantum walks, as well as strongly correlated Bloch oscillations
in tilted optical lattices. Our approach can be scaled to larger systems,
greatly extending the class of problems accessible via quantum walksComment: 8 pages, 4 figures, 1 tabl
Assessment of Natural Resources Use for Sustainable Development - DPSIR Framework for Case Studies in Portsmouth and Thames Gateway, U.K.
This chapter reports on the uses of the DPSIR framework to assess the sustainability of the intertidal environments within the two UK case study areas, Portsmouth and Thames Gateway. It focuses on statutory conservation areas dominated by intertidal habitats. Two are located in Portsmouth (Portsmouth and Langstone Harbours) and four in the Thames Gateway (Benfleet Marshes, South Thames Estuary, Medway Estuary and the Swale in the Thames Gateway). Based on the reduction of a number of pressures and impacts observed in recent decades and the improvement of overall environmental quality, all six SSSIs are considered to be sustainable in the short and medium term. In the future, it is possible that the impacts of climate change, especially sea-level rise, might result in further reduction in the area and/or quality of intertidal habitats. Further integration between conservation and planning objectives (both for urban development and management of flood risk) at local level is needed to support the long-term sustainability of intertidal habitats
Design and verification of a micro wells turbine for Mediterranean operations
In the framework of the Poseidone Project we have designed a Wells turbine for Mediterranean
operations. Here we present RANS computations carried out with OpenFOAM at different
operating conditions. Rotor-stator interaction was synthetized with MRF approach and RANS
closure relied on the cubic eddy viscosity closure of Lien et al. The virtual test rig reproduced
the ISO conditions of the laboratory and was able to correctly predict torque and efficiency at
different operations. Computations moreover allowed to acquire information on the threedimensional
velocity and pressure field that develops inside the Wells turbine. The aim was to
have an insight on the secondary motions and on the possible stall mechanism that characterize
the device at low flow rates. Results were successfully validated against experimental measures
En face optical coherence tomography of foveal microstructure in full-thickness macular hole: a model to study perifoveal müller cells.
PURPOSE: To characterize perifoveal intraretinal cavities observed around full-thickness macular holes (MH) using en face optical coherence tomography and to establish correlations with histology of human and primate maculae.
DESIGN: Retrospective nonconsecutive observational case series.
METHODS: Macular en face scans of 8 patients with MH were analyzed to quantify the areas of hyporeflective spaces, and were compared with macular flat mounts and sections from 1 normal human donor eye and 2 normal primate eyes (Macaca fascicularis). Immunohistochemistry was used to study the distribution of glutamine synthetase, expressed by Müller cells, and zonula occludens-1, a tight-junction protein.
RESULTS: The mean area of hyporeflective spaces was lower in the inner nuclear layer (INL) than in the complex formed by the outer plexiform (OPL) and the Henle fiber layers (HFL): 5.0 × 10(-3) mm(2) vs 15.9 × 10(-3) mm(2), respectively (P < .0001, Kruskal-Wallis test). In the OPL and HFL, cavities were elongated with a stellate pattern, whereas in the INL they were rounded and formed vertical cylinders. Immunohistochemistry confirmed that Müller cells followed a radial distribution around the fovea in the frontal plane and a "Z-shaped" course in the axial plane, running obliquely in the OPL and HFL and vertically in the inner layers. In addition, zonula occludens-1 co-localized with Müller cells within the complex of OPL and HFL, indicating junctions in between Müller cells and cone axons.
CONCLUSION: The dual profile of cavities around MHs correlates with Müller cell morphology and is consistent with the hypothesis of intra- or extracellular fluid accumulation along these cells
Mantra 2.0: An online collaborative resource for drug mode of action and repurposing by network analysis
Elucidation of molecular targets of a compound (mode of action, MoA) and of its off-targets is a crucial step in drug development. We developed an online collaborative resource (MANTRA 2.0) that supports this process by exploiting similarities between drug-induced transcriptional profiles. Drugs are organised in a network of nodes (drugs) and edges (similarities) highlighting “communities” of drugs sharing a similar MoA. A user can upload gene expression profiles (GEPs) before and after drug treatment in one or multiple cell types. An automated processing pipeline transforms the GEPs into a unique drug ”node” embedded in the drug-network. Visual inspection of the neighbouring drugs and communities helps in revealing its MoA, and to suggest new applications of known drugs (drug repurposing). MANTRA 2.0 allows storing and sharing user-generated network nodes, thus making MANTRA 2.0 a collaborative ever-growing resource
Time-lapse characterization of hydrothermal seawater and microbial interactions with basaltic tephra at Surtsey Volcano
A new International Continental Drilling Program (ICDP) project will drill through the 50-yearoldedifice of Surtsey Volcano, the youngest of the Vestmannaeyjar Islands along the south coast of Iceland, to perform interdisciplinary time-lapse investigations of hydrothermal and microbial interactions with basaltic tephra. The volcano, created in 1963–1967 by submarine and subaerial basaltic eruptions, was first drilled in 1979. In October 2014, a workshop funded by the ICDP convened 24 scientists from 10 countries for 3 and a half days on Heimaey Island to develop scientific objectives, site the drill holes, and organize logistical support. Representatives of the Surtsey Research Society and Environment Agency of Iceland also participated. Scientific themes focus on further determinations of the structure and eruptive processes of the type locality of Surtseyan volcanism, descriptions of changes in fluid geochemistry and microbial colonization of the subterrestrial deposits since drilling 35 years ago, and monitoring the evolution of hydrothermal and biological processes within the tephra deposits far into the future through the installation of a Surtsey subsurface observatory. The tephra deposits provide a geologic analog for developing specialty concretes with pyroclastic rock and evaluating their long-term performance under diverse hydrothermal conditions
Numerical study on active and passive trailing edge morphing applied to a multi-MW wind turbine section
A progressive increasing in turbine dimension has characterized the
technological evelopment in offshore wind energy utilization. This aspect reflects on
the growing in blade length and weight. For very large turbines, the standard control systems may
not be optimal to give the best performance and the best vibratory load damping, keeping the
condition of maximum energy production. For this reason, some new solutions have been
proposed in research. One of these is the possibility of morphs the blade surface in an active way
(increasing the performance in low wind region) or passive (load reduction) way.
In this work, we present a numerical study on the active and passive trailing edge
morphing, applied to large wind turbines. In particular, the study focuses on the aerodynamic
response of a midspan blade section, in terms of fluid structure interaction (FSI) and driven
surface deformation.
We test the active system in a simple start-up procedure and the passive system in a power
production with turbulent wind conditions, that is, two situations in which we expect these systems
could improve the performance.
All the computations are carried out with a FSI code, which couples a 2D-CFD solver, a moving mesh
solver (both implemented in OpenFOAM library) and a FEM solver.
We evaluate all the boundary conditions to apply in the section problem by simulating the
5MW NREL wind turbine with the NREL CAE-tools developed for wind turbine simulation
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