Memristor-based LSTM neuromorphic circuits for offshore wind turbine blade fault detection

The UK offshore wind industry is rapidly growing to meet CO2 emission targets. However, the main drawback of the offshore environment is the increased cost of maintenance. Artificial Neural Networks (ANN) show great potential to reduce this cost. Long Short-Term Memory (LSTM) is a form of Recurrent Neural Network (RNN) that shows promising results in solving time series-based problems, making them ideally suited for wind turbine condition monitoring. A dedicated circuit for a LSTM-based ANN that uses memristors will allow for more power efficient and faster computation, whilst being able to overcome the von Neumann bottleneck

NGC 4102: High Resolution Infrared Observations of a Nuclear Starburst Ring

The composite galaxy NGC 4102 hosts a LINER nucleus and a starburst. We mapped NGC 4102 in the 12.8 micron line of [NeII], using the echelon spectrometer TEXES on the NASA IRTF, to obtain a data cube with 1.5" spatial and 25 km/s spectral, resolution. Combining near-infrared, radio, and the [NeII] data shows that the extinction to the starburst is substantial, more than 2 magnitudes at K band, and that the neon abundance is less than half solar. We find that the star formation in the nuclear region is confined to a rotating ring or disk of 4.3" (~300 pc) diameter, inside the Inner Lindblad Resonance. This region is an intense concentration of mass, with a dynamical mass of ~3 x 10^9 solar masses, and of star formation. The young stars in the ring produce the [NeII] flux reported by Spitzer for the entire galaxy. The mysterious blue component of line emission detected in the near-infrared is also seen in [NeII]; it is not a normal AGN outflow.Comment: submitted to Ap

Iron and silicon isotope behaviour accompanying weathering in Icelandic soils, and the implications for iron export from peatlands

peer reviewe

Spatial distribution of interstellar gas in the innermost 3 kpc of our Galaxy

We review the present observational knowledge on the spatial distribution and the physical state of the different (molecular, atomic and ionized) components of the interstellar gas in the innermost 3 kpc of our Galaxy -- a region which we refer to as the interstellar Galactic bulge, to distinguish it from its stellar counterpart. We try to interpret the observations in the framework of recent dynamical models of interstellar gas flows in the gravitational potential of a barred galaxy. Finally, relying on both the relevant observations and their theoretical interpretation, we propose a model for the space-averaged density of each component of the interstellar gas in the interstellar Galactic bulge.Comment: 19 pages, 11 figure

The structure of the agrochemical fungicidal 4-Chloro-3-(3,5-dichloropheny)-1H-pyrazole, RPA 406194 and related compounds

The difficulties to obtain convenient monocrystals of the important fungicide RPA 406194 have been overcome by a combination of solid state 13C NMR, X-ray powder diffraction and molecular modeling. The compound, a 3-aryl tautomer, crystallizes forming infinite chains of molecules bonded by N–H· · ·N hydrogen bonds, leading to needle-shaped crystals. The tautomerism (equilibrium constant and energy barrier) of this compound in solution has been studied

Rapid Primary Sulfate Aerosol Generation Observed With OP‐FTIR in the Eruptive Plume of the Fagradalsfjall Basaltic Eruption, Iceland, 2021

Open‐Path Fourier‐Transform Infrared (OP‐FTIR) absorption spectroscopy is a powerful method for remote characterization of volcanic plume composition from safe distances. Many studies have used it to examine the composition of volcanic gas emitted at the surface, which is influenced by initial volatile contents and magma ascent/storage processes, and help to reveal the dynamics controlling surface activity. However, to evaluate the health hazard threats associated with volcanic emissions and their potential impact on wider atmospheric conditions, near‐source particle measurements are also key. Here we present a forward model and fitting algorithm which allows quantification of particle size and abundance. This was successfully applied to radiometrically uncalibrated OP‐FTIR spectra collected with a highly dynamic radiation source during the Fagradalsfjall eruption, Iceland, on 11 August 2021. Quantification of plume temperatures ranging from 350 to 650 K was essential to characterize the emission‐absorption behavior of SO2, enabling retrievals of particulate matter in the thermal infrared spectral window (750–1250 cm−1) in each spectrum. For the first time, we observe the rapid formation of primary aerosols in young plumes (only a few seconds old) with OP‐FTIR. Temperature‐dependent SO2/SO42− molar ratios range from 100 to 250, consistent with a primary formation mechanism controlled by cooling and entrainment of atmospheric gases. This novel aerosol spectrum retrieval opens new frontiers in field‐based measurements of sulfur partitioning and volcanic plume evolution, with the potential to improve volcano monitoring and quantification of air quality hazard assessments

Desingularization of vortices for the Euler equation

We study the existence of stationary classical solutions of the incompressible Euler equation in the plane that approximate singular stationnary solutions of this equation. The construction is performed by studying the asymptotics of equation -\eps^2 \Delta u^\eps=(u^\eps-q-\frac{\kappa}{2\pi} \log \frac{1}{\eps})_+^p with Dirichlet boundary conditions and $q$ a given function. We also study the desingularization of pairs of vortices by minimal energy nodal solutions and the desingularization of rotating vortices.Comment: 40 page

Space and time-related firing in a model of hippocampo-cortical interactions

International audienceIn a previous model [3], a spectral timing neural network [4] was used to account for the role of the Hs in the acquisition of classical conditioning. The ability to estimate the timing between separate events was then used to learn and predict transitions between places in the environment. We propose a neural architecture based on this work and explaining the out-of-field activities in the Hs along with their temporal prediction capabilities. The model uses the hippocampo-cortical pathway as a means to spread reward signals to entorhinal neurons. Secondary predictions of the reward signal are then learned, based on transition learning, by pyramidal neurons of the CA region

Bostonia: 1998-1999, no. 1, 3-4

Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs

General relativistic Sagnac formula revised

The Sagnac effect is a time or phase shift observed between two beams of light traveling in opposite directions in a rotating interferometer. We show that the standard description of this effect within the framework of general relativity misses the effect of deflection of light due to rotational inertial forces. We derive the necessary modification and demonstrate it through a detailed analysis of the square Sagnac interferometer rotating about its symmetry axis in Minkowski space-time. The role of the time shift in a Sagnac interferometer in the synchronization procedure of remote clocks as well as its analogy with the Aharanov-Bohm effect are revised.Comment: 11 pages, 3 figure