2,402 research outputs found
Anodising AA5083 aluminium alloy using ionic liquids
Aluminium, as the current collector in lithium batteries, has shown reduced corrosion susceptibility in room temperature molten salts (1, 2). Moreover, previous studies have established that corrosion mitigation is achieved on magnesium alloys using ionic liquids pretreatments (3, 4). This paper investigated the anodisation of AA5083 aluminium alloy in Trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfony) ([P6,6,6,14][NTf2]) ionic liquid by applying a constant current followed by holding at the maximum potential for a period of time. Potentiodynamic polarisation results show that the treated surfaces were more corrosion resistant in 0.1 M sodium chloride solution compared with the control specimen. The anodising treatment was effective both in shifting the free corrosion potential to more noble values and in suppressing the corrosion current. Optical microscope and optical profilometry images indicated that an anodising film was deposited onto the alloy surface, which is thought to have inhibited corrosion in chloride environment. Further characterisation of the anodising film will be carried out in future work
Exploring binary black hole mergers and host galaxies with {\sc Shark} and COMPAS
In this work, we explore the connection between the gravitational wave (GW)
merger rates of stellar-mass binary black holes (BBH) and galaxy properties. We
do this by generating populations of stars using the binary synthesis code
COMPAS and evolving them in galaxies from the semi-analytic galaxy formation
model {\sc Shark}, to determine the number of mergers occurring in each
simulation time-step. We find that large, metal-rich galaxies with high star
formation rates are more likely to have gravitational wave (GW) events compared
to younger, more metal poor galaxies. Our simulation with the default input
parameters predicts a higher local merger rate density compared to the third
gravitational wave transient catalogue (GWTC-3) prediction from LIGO, VIRGO and
KAGRA. This is due to short coalescence times, low metallicities and an high
formation rate of stars at low redshift in the galaxy simulation, which
produces more BBHs that merge within the age of the Universe compared to
observations. We identify alternate remnant mass models that more accurately
reproduce the observed volumetric rate and provide updated fits to the merger
rate distribution as a function of redshift. We then investigate the relative
fraction of GW events in our simulation volume that are in observable host
galaxies from different upcoming photometric and spectroscopic surveys,
determining which of those are more ideal for tracing host galaxies with high
merger rates. The implications of this work can be utilised for numerous
applications, including for constraining stellar evolution models, better
informing follow-up programs, and placing more informative priors on potential
host galaxies when measuring cosmological parameters such as the Hubble
constant.Comment: 19 pages, 16 figures - Will be submitted to MNRA
The current status of radiological clinical audit and feedback on the ESR Guide to Clinical Audit in Radiology and the ESR Clinical Audit Tool (Esperanto) â an ESR Survey of European Radiology Departments
Clinical audit âaccording to national proceduresâ is a legal requirement as defined within the recently implemented European Council Basic Safety Standards Directive (BSSD), 2013/59/Euratom. A survey was undertaken in 2019 to assess the current status of clinical audit in European radiology departments and for feedback on the recently published âESR Guide to Clinical Audit in Radiologyâ and the âESR Clinical Audit Tool (Esperanto)â. The survey was distributed within the European Society of Radiology (ESR) EuroSafe Imaging Star network and also to European national radiological societies which are institutional members of the ESR
Soil Carbon in Agroforestry Systems: An Unexplored Treasure?
Soil organic matter (SOM), which contains more reactive organic carbon (C) than any other single terrestrial pool, plays a major role in determining C storage in ecosystems and regulating atmospheric concentrations of carbon dioxide (CO2)^1^. Agroforestry, the practice of growing trees and crops in interacting combinations on the same unit of land^2^, primarily by resource-poor smallholder farmers in developing countries, is recognized as a strategy for soil carbon sequestration (SCS) under the Clean Development Mechanism (CDM) of the Kyoto Protocol^3^. The understanding about C storage and dynamics under agroforestry systems (AFS), however, is minimal. Our studies under various AFS in diverse ecological conditions in five countries showed that tree-based agricultural systems, compared to treeless systems, stored more C in deeper soil layers up to 1 m depth under comparable conditions. More C is stored in soil near the tree than away from the tree; higher SOC content is associated with higher species richness and tree density; and C3 plants (trees) contribute to more C in the silt- + clay-sized (<53 µm) fractions that constitute more stable C, than C4 plants, in deeper soil profiles4 - 8. These results provide clear indications of the possibilities for climate change mitigation through SCS in AFS, and opportunities for economic benefit - through carbon trading - to millions of smallholder farmers in developing countries
Categorification of a linear algebra identity and factorization of Serre functors
We provide a categorical interpretation of a well-known identity from linear
algebra as an isomorphism of certain functors between triangulated categories
arising from finite dimensional algebras.
As a consequence, we deduce that the Serre functor of a finite dimensional
triangular algebra A has always a lift, up to shift, to a product of suitably
defined reflection functors in the category of perfect complexes over the
trivial extension algebra of A.Comment: 18 pages; Minor changes, references added, new Section 2.
Earliest Cretaceous cocoons or plant seed structures from the Wealden Group, Hastings, UK
We thank Jason Hilton (University of Birmingham) and Alan Spencer (Imperial College) for discussion. RG is a member of the Interdisciplinary Centre for Ancient Life (UMRI). We are grateful for the reviews of both Jorge Genise, and Duncan McIlroy whose comments and guidance greatly improved the manuscript.Postprin
Disease Modelling of Cognitive Outcomes and Biomarkers in the European Prevention of Alzheimerâs Dementia Longitudinal Cohort
A key challenge for the secondary prevention of Alzheimerâs dementia is the need to identify individuals early on in the disease process through sensitive cognitive tests and biomarkers. The European Prevention of Alzheimerâs Dementia (EPAD) consortium recruited participants into a longitudinal cohort study with the aim of building a readiness cohort for a proof-of-concept clinical trial and also to generate a rich longitudinal data-set for disease modelling. Data have been collected on a wide range of measurements including cognitive outcomes, neuroimaging, cerebrospinal fluid biomarkers, genetics and other clinical and environmental risk factors, and are available for 1,828 eligible participants at baseline, 1,567 at 6 months, 1,188 at one-year follow-up, 383 at 2 years, and 89 participants at three-year follow-up visit. We novelly apply state-of-the-art longitudinal modelling and risk stratification approaches to these data in order to characterise disease progression and biological heterogeneity within the cohort. Specifically, we use longitudinal class-specific mixed effects models to characterise the different clinical disease trajectories and a semi-supervised Bayesian clustering approach to explore whether participants can be stratified into homogeneous subgroups that have different patterns of cognitive functioning evolution, while also having subgroup-specific profiles in terms of baseline biomarkers and longitudinal rate of change in biomarkers
CMB power spectrum parameter degeneracies in the era of precision cosmology
Cosmological parameter constraints from the CMB power spectra alone suffer
several well-known degeneracies. These degeneracies can be broken by numerical
artefacts and also a variety of physical effects that become quantitatively
important with high-accuracy data e.g. from the Planck satellite. We study
degeneracies in models with flat and non-flat spatial sections, non-trivial
dark energy and massive neutrinos, and investigate the importance of various
physical degeneracy-breaking effects. We test the CAMB power spectrum code for
numerical accuracy, and demonstrate that the numerical calculations are
accurate enough for degeneracies to be broken mainly by true physical effects
(the integrated Sachs-Wolfe effect, CMB lensing and geometrical and other
effects through recombination) rather than numerical artefacts. We quantify the
impact of CMB lensing on the power spectra, which inevitably provides
degeneracy-breaking information even without using information in the
non-Gaussianity. Finally we check the numerical accuracy of sample-based
parameter constraints using CAMB and CosmoMC. In an appendix we document recent
changes to CAMB's numerical treatment of massive neutrino perturbations, which
are tested along with other recent improvements by our degeneracy exploration
results.Comment: 27 pages, 28 figures. Latest CAMB version available from
http://camb.info/. Reduced number of figures, plot legend corrected and minor
edits to match published versio
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