411 research outputs found
Oil Spill Drone: A Dataset of Drone-Captured, Segmented RGB Images for Oil Spill Detection in Port Environments
The high incidence of oil spills in port areas poses a serious threat to the
environment, prompting the need for efficient detection mechanisms. Utilizing
automated drones for this purpose can significantly improve the speed and
accuracy of oil spill detection. Such advancements not only expedite cleanup
operations, reducing environmental harm but also enhance polluter
accountability, potentially deterring future incidents. Currently, there's a
scarcity of datasets employing RGB images for oil spill detection in maritime
settings. This paper presents a unique, annotated dataset aimed at addressing
this gap, leveraging a neural network for analysis on both desktop and edge
computing platforms. The dataset, captured via drone, comprises 1268 images
categorized into oil, water, and other, with a convolutional neural network
trained using an Unet model architecture achieving an F1 score of 0.71 for oil
detection. This underscores the dataset's practicality for real-world
applications, offering crucial resources for environmental conservation in port
environments
ESR evidence for disordered magnetic phase from ultra-small carbon nanotubes embedded in zeolite nanochannels
A multi-frequency electron spin resonance (ESR) study provides evidence for
the occurrence of low temperature ferromagnetic/spin-glass behavior in aligned
arrays of sub-nanometer single walled carbon nanotubes confined in zeolite
nano-channels, owing to sp2-type non-bonding carbon associated localized states
with density of ~3 x 1019 /g. Features related to the much anticipated
conduction ESR are not detected. In the paramagnetic phase, the ESR linewidth
is found to be weakly dependent on microwave frequency.Comment: Accepted to be published in EuroPhysics Letter
Semiclassical bounds on dynamics of two-dimensional interacting disordered fermions
Using the truncated Wigner approximation (TWA) we study quench dynamics of
two-dimensional lattice systems consisting of interacting spinless fermions
with potential disorder. First, we demonstrate that the semiclassical dynamics
generally relaxes faster than the full quantum dynamics. We obtain this result
by comparing the semiclassical dynamics with exact diagonalization and Lanczos
propagation of one-dimensional chains. Next, exploiting the TWA capabilities of
simulating large lattices, we investigate how the relaxation rates depend on
the dimensionality of the studied system. We show that strongly disordered
one-dimensional and two-dimensional systems exhibit a transient,
logarithmic-in-time relaxation, which was recently established for
one-dimensional chains. Such relaxation corresponds to the infamous -noise
at strong disorder.Comment: 9 pages, 9 figure
Oxygen precursor to the reactive intermediate in methanol synthesis by Cu-ZSM-5
The reactive oxidizing species in the selective oxidation of methane to methanol in oxygen activated Cu-ZSM-5 was recently defined to be a bent mono(μ-oxo)dicopper(II) species, [Cu_2O]^(2+). In this communication we report the formation of an O_2-precursor of this reactive site with an associated absorption band at 29,000 cm^(-1). Laser excitation into this absorption feature yields a resonance Raman (rR) spectrum characterized by ^(18)O_2 isotope sensitive and insensitive vibrations, νO-O and νCu-Cu, at 736 (Δ^(18)O_2 = 41 cm^(-1)) and 269 cm^(-1), respectively. These define the precursor to be a μ-(η^2:η^2) peroxo dicopper(II) species, [Cu_2(O_2)]^(2+). rR experiments in combination with UV-vis absorption data show that this [Cu_2(O_2)]^(2+) species transforms directly into the [Cu_2O]^(2+) reactive site. Spectator Cu^+ sites in the zeolite ion-exchange sites provide the two electrons required to break the peroxo bond in the precursor. O_2-TPD experiments with ^(18)O_2 show the incorporation of the second ^(18)O atom into the zeolite lattice in the transformation of [Cu_2(O_2)]^(2+) into [Cu_2O]^(2+). This study defines the mechanism of oxo-active site formation in Cu-ZSM-5
Ligand migration from cluster to support: a crucial factor for catalysis by Thiolate-protected gold clusters
Thiolate
protected
metal
clusters
are valuable
precursors
for the
design
of tailored
nanosized
catalysts.
Their
performance
can
be tuned
precisely
at atomic
level,
e.g. by the configuration/
type
of ligands
or by partial/complete
removal
of the ligand
shell
through
controlled
pre-treatment
steps.
However,
the
interaction
between
the ligand
shell
and
the oxide
support,
as
well
as ligand
removal
by oxidative
pre-treatment,
are
still
poorly
understood.
Typically,
it was
assumed
that
the thiolate
ligands
are simply
converted
into
SO
2
, CO
2
and
H
2
O. Herein,
we
report
the first
detailed
observation
of sulfur
ligand
migration
from
Au to the oxide
support
upon
deposition
and
oxidative
pre-treatment,
employing
mainly
S K-edge
XANES.
Conse-
quently,
thiolate
ligand
migration
not only
produces
clean
Au
cluster
surfaces
but
also
the
surrounding
oxide
support
is
modified
by sulfur-containing
species,
with
pronounced
effects
on catalytic
propertiesPeer ReviewedPostprint (published version
Oxygen precursor to the reactive intermediate in methanol synthesis by Cu-ZSM-5
The reactive oxidizing species in the selective oxidation of methane to methanol in oxygen activated Cu-ZSM-5 was recently defined to be a bent mono(μ-oxo)dicopper(II) species, [Cu_2O]^(2+). In this communication we report the formation of an O_2-precursor of this reactive site with an associated absorption band at 29,000 cm^(-1). Laser excitation into this absorption feature yields a resonance Raman (rR) spectrum characterized by ^(18)O_2 isotope sensitive and insensitive vibrations, νO-O and νCu-Cu, at 736 (Δ^(18)O_2 = 41 cm^(-1)) and 269 cm^(-1), respectively. These define the precursor to be a μ-(η^2:η^2) peroxo dicopper(II) species, [Cu_2(O_2)]^(2+). rR experiments in combination with UV-vis absorption data show that this [Cu_2(O_2)]^(2+) species transforms directly into the [Cu_2O]^(2+) reactive site. Spectator Cu^+ sites in the zeolite ion-exchange sites provide the two electrons required to break the peroxo bond in the precursor. O_2-TPD experiments with ^(18)O_2 show the incorporation of the second ^(18)O atom into the zeolite lattice in the transformation of [Cu_2(O_2)]^(2+) into [Cu_2O]^(2+). This study defines the mechanism of oxo-active site formation in Cu-ZSM-5
Ebstein’s anomaly may be caused by mutations in the sarcomere protein gene MYH7
Ebstein's anomaly is a rare congenital heart malformation characterised by adherence of the septal and posterior leaflets of the tricuspid valve to the underlying myocardium. Associated abnormalities of left ventricular morphology and function including left ventricular noncompaction (LVNC) have been observed. An association between Ebstein's anomaly with LVNC and mutations in the sarcomeric protein gene MYH7, encoding β-myosin heavy chain, has been shown by recent studies. This might represent a specific subtype of Ebstein's anomaly with a Mendelian inheritance pattern. In this review we discuss the association of MYH7 mutations with Ebstein's anomaly and LVNC and its implications for the clinical care for patients and their family members.Congenital Heart Diseas
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