3,213 research outputs found
Concepts for design of an energy management system incorporating dispersed storage and generation
New forms of generation based on renewable resources must be managed as part of existing power systems in order to be utilized with maximum effectiveness. Many of these generators are by their very nature dispersed or small, so that they will be connected to the distribution part of the power system. This situation poses new questions of control and protection, and the intermittent nature of some of the energy sources poses problems of scheduling and dispatch. Under the assumption that the general objectives of energy management will remain unchanged, the impact of dispersed storage and generation on some of the specific functions of power system control and its hardware are discussed
Structure of self-assembled Mn atom chains on Si(001)
Mn has been found to self-assemble into atomic chains running perpendicular
to the surface dimer reconstruction on Si(001). They differ from other atomic
chains by a striking asymmetric appearance in filled state scanning tunneling
microscopy (STM) images. This has prompted complicated structural models
involving up to three Mn atoms per chain unit. Combining STM, atomic force
microscopy and density functional theory we find that a simple necklace-like
chain of single Mn atoms reproduces all their prominent features, including
their asymmetry not captured by current models. The upshot is a remarkably
simpler structure for modelling the electronic and magnetic properties of Mn
atom chains on Si(001).Comment: 5 pages, 4 figure
Electronic coupling between Bi nanolines and the Si(001) substrate: An experimental and theoretical study
Atomic nanolines are one dimensional systems realized by assembling many
atoms on a substrate into long arrays. The electronic properties of the
nanolines depend on those of the substrate. Here, we demonstrate that to fully
understand the electronic properties of Bi nanolines on clean Si(001) several
different contributions must be accounted for. Scanning tunneling microscopy
reveals a variety of different patterns along the nanolines as the imaging bias
is varied. We observe an electronic phase shift of the Bi dimers, associated
with imaging atomic p-orbitals, and an electronic coupling between the Bi
nanoline and neighbouring Si dimers, which influences the appearance of both.
Understanding the interplay between the Bi nanolines and Si substrate could
open a novel route to modifying the electronic properties of the nanolines.Comment: 6 pages (main), 2 pages (SI), accepted by Phys. Rev.
Slope monitoring at the Glan Ebbw Landslide, Blaina, South Wales: January to April 2016
This report describes survey work carried out at a landslide site in Blaina, West Side, South Wales between January and April 2016. The Terrestrial Laser Scan (LiDAR) and GPS survey of ground pins was undertaken and funded by the British Geological Survey (BGS). The aim was to provide Blaenau Gwent Council Environment Department with a survey baseline against which further ground movement can be assessed and data for research purposes
Susceptibility Mapping in Sickle Cell Anaemia Patients with and Without Chronic Blood Transfusions
Sickle cell anaemia (SCA) is a genetic disorder affecting haemoglobin. Previous studies suggest that the iron content in some deep-brain regions is higher in transfused SCA patients (TSCA) than in healthy controls (HC). We hypothesised that iron content in those regions is lower in non-transfused patients (NSCA) than in controls as NSCA have low haematocrit. A pilot study (5 TSCA, 5 NSCA, 5 HC) showed that susceptibility values were significantly lower in the globus pallidus of both TSCA and NSCA than in HC, supporting our second hypothesis. A larger study (20 NSCA, 18 HC) showed a trend in this direction
Dynamic platform to recreate an osteoarthritic 3D in vitro model
Osteoarthritis (OA), a prevalent chronic condition with a striking impact on life quality,
represents an enormous societal burden that increases greatly as populations’ age. Yet
no approved pharmacological intervention, biologic therapy or procedure prevents the
progressive destruction of the OA joint. Based on bilayered structures that have been
previously suggested for osteochondral (OC) applications (Oliveira et al 2006) and on
the potential of methacrylated gelatin (GelMA) and methacrylated gellan gum (MAGG)
for different tissue engineering applications (Silva-Correia et al 2013, Tasoglu et al
2014), we set a dynamic platform for the in vitro recreation of an OA 3D in vitro model.
Since OA is an inflammatory and degenerative disorder affecting cartilage and
subchondral bone, we created 6 hybrid formulations recreating a 3D controlled
subchondral bone and cartilage integrated microenvironment. Fat pad adipose derived
stem cells (ASCs) were isolated from Hoffa’s body obtained from healthy Patients,
characterized by flow cytometry and their performance in the developed 3D structures
assessed. GelMA formulation showed the best cell adhesion and proliferation, but the
life-time of this one in culture is shorter due to the faster degradation in vitro comparing
to MAGG based structures. According to this we proceeded with the best hybrid
formulation, GelMA-MAGG 2:1, for OC co-differentiation using a dual-chamber
bioreactor designed for the establishment of co-cultures in a single 3D structure
(Canadas et al 2014). This approach solved challenges of 3D cell culture in interfaced
tissues as OC and will ultimately be used for OA in vitro modelinginfo:eu-repo/semantics/publishedVersio
Self-avoiding walks on a bilayer Bethe lattice
We propose and study a model of polymer chains in a bilayer. Each chain is
confined in one of the layers and polymer bonds on first neighbor edges in
different layers interact. We also define and comment results for a model with
interactions between monomers on first neighbor sites of different layers. The
thermodynamic properties of the model are studied in the grand-canonical
formalism and both layers are considered to be Cayley trees. In the core region
of the trees, which we may call a bilayer Bethe lattice, we find a very rich
phase diagram in the parameter space defined by the two activities of monomers
and the Boltzmann factor associated to the interlayer interaction between bonds
or monomers. Beside critical and coexistence surfaces, there are tricritical,
bicritical and critical endpoint lines, as well as higher order multicritical
points.Comment: 21 pages, 10 figures. Journal of Statistical Mechanics: Theory and
Experiment (in press
The opposites task: Using general rules to test cognitive flexibility in preschoolers
A brief narrative description of the journal article, document, or resource. Executive functions play an important role in cognitive development, and during the preschool years especially, children's performance is limited in tasks that demand flexibility in their behavior. We asked whether preschoolers would exhibit limitations when they are required to apply a general rule in the context of novel stimuli on every trial (the "opposites" task). Two types of inhibitory processing were measured: response interference (resistance to interference from a competing response) and proactive interference (resistance to interference from a previously relevant rule). Group data show 3-year-olds have difficulty inhibiting prepotent tendencies under these conditions, whereas 5-year-olds' accuracy is near ceiling in the task. (Contains 4 footnotes and 1 table.
Multivariate and network meta-analysis of multiple outcomes and multiple treatments: rationale, concepts, and examples
Organisations such as the National Institute for Health and Care Excellence require the synthesis of evidence from existing studies to inform their decisions—for example, about the best available treatments with respect to multiple efficacy and safety outcomes. However, relevant studies may not provide direct evidence about all the treatments or outcomes of interest. Multivariate and network meta-analysis methods provide a framework to address this, using correlated or indirect evidence from such studies alongside any direct evidence. In this article, the authors describe the key concepts and assumptions of these methods, outline how correlated and indirect evidence arises, and illustrate the contribution of such evidence in real clinical examples involving multiple outcomes and multiple treatment
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