The Shellless Supernova Remnant B0532–67.5 in the Large Magellanic Cloud

The supernova remnant (SNR) B0532−67.5 in the Large Magellanic Cloud (LMC) was first diagnosed by its nonthermal radio emission, and its SNR nature was confirmed by the observation of diffuse X-ray emission; however, no optical SNR shell is detected. The OB association LH75, or NGC 2011, is projected within the boundary of this SNR. We have analyzed the massive star population in and around SNR B0532−67.5 using optical photometric data to construct color–magnitude diagrams, using stellar evolutionary tracks to estimate stellar masses, and using isochrones to assess the stellar ages. From these analyses, we find a 20–25 Myr population in LH75 and a younger population less than 10 Myr old to the southwest of LH75. The center of SNR B0532−67.5 is located closer to the core of LH75 than to the massive stars to its southwest. We conclude that the supernova progenitor was probably a member of LH75 with an initial mass of ∼15 M ⊙. The supernova exploded in an H i cavity excavated by the energy feedback of LH75. The low density of the ambient medium prohibits the formation of a visible nebular shell. Despite the low density in the ambient medium, physical properties of the hot gas within the SNR interior do not differ from SNRs with a visible shell by more than a factor of 2–3. The large-scale H i map shows that SNR B0532−67.5 is projected in a cavity that appears to be connected with the much larger cavity of the supergiant shell LMC-4.

Starburst Energy Feedback Seen through HCO+/HOC+ Emission in NGC 253 from ALCHEMI

Molecular abundances are sensitive to the UV photon flux and cosmic-ray ionization rate. In starburst environments, the effects of high-energy photons and particles are expected to be stronger. We examine these astrochemical signatures through multiple transitions of HCO+ and its metastable isomer HOC+ in the center of the starburst galaxy NGC 253 using data from the Atacama Large Millimeter/submillimeter Array large program ALMA Comprehensive High-resolution Extragalactic Molecular inventory. The distribution of the HOC+(1−0) integrated intensity shows its association with “superbubbles,” cavities created either by supernovae or expanding H ii regions. The observed HCO+/HOC+ abundance ratios are ∼10–150, and the fractional abundance of HOC+ relative to H2 is ∼1.5 × 10−11–6 × 10−10, which implies that the HOC+ abundance in the center of NGC 253 is significantly higher than in quiescent spiral arm dark clouds in the Galaxy and the Galactic center clouds. Comparison with chemical models implies either an interstellar radiation field of G 0 ≳ 103 if the maximum visual extinction is ≳5, or a cosmic-ray ionization rate of ζ ≳ 10−14 s−1 (3–4 orders of magnitude higher than that within clouds in the Galactic spiral arms) to reproduce the observed results. From the difference in formation routes of HOC+, we propose that a low-excitation line of HOC+ traces cosmic-ray dominated regions, while high-excitation lines trace photodissociation regions. Our results suggest that the interstellar medium in the center of NGC 253 is significantly affected by energy input from UV photons and cosmic rays, sources of energy feedback.

Exploring domestic energy consumption feedback through interactive annotation

We report on a three-week field study in which participants from nine households were asked to annotate their domestic electricity consumption data using a prototype interactive visualisation. Through an analysis of the annotations and semi-structured interviews, our findings suggest that the intervention helped participants to develop a detailed and accurate understanding of their electricity consumption data. Our results suggest that energy data visualisations can be improved by having users actively manipulate and annotate their data, as doing so encourages reflection on how energy is being used, facilitating insights on how consumption can be reduced. One of the key findings from our thematic analysis was that participants went beyond the data in their reflections, talking about generational issues, upbringing, financial matters, socio-economic comparisons, environmental concern, mistrust towards utilities, convenience, comfort and self-reported waste. Reading beyond the data illustrates the importance of social practices in the context of energy feedback, embedding eco-feedback research into the relevant context of sociology and psychology research.

Experimental Research on Braking Feedback and Taxiing Feedback System of New Energy Vehicles

This paper took a new energy vehicle feedback system as the research object, aiming to study the energy recovery law of the new energy vehicle under braking feedback and taxiing feedback conditions. Firstly, the braking energy feedback control strategy and different forms of taxiing energy feedback were studied. Then the integration and application of braking energy recovery system were carried out on a pure electric bus and a hybrid electric bus, with each vehicle model corresponding to different integration and test schemes, which provided a guarantee for the relevant test of real vehicle environments. Finally, relevant vehicle experiments were carried out to test the impact of superposition and coordination strategies on the contribution rate of braking energy recovery under a typical Chinese city bus circle and compared the difference in vehicle energy consumption with and without taxi feedback strategy. The test results showed that the coordinated braking energy recovery control strategy can make more effective use of the maximum torque that can be fed back by the motor, and the fuel consumption of the taxiing feedback mode was lower than that of the no taxiing feedback mode under different driving conditions.

Intrinsic and Wind-Driven Decadal Variability of the Kuroshio Extension in Altimeter Observations

In this work we use satellite altimeter observations to study the mechanism of decadal variability of the Kuroshio Extension (KE), with special attention on jet-eddy energy transfer, and on the relationship between the wind-driven sea surface height anomalies (SSHAs) and those directly driven by intrinsic oceanic processes including jet and eddies. It is shown that energy feedback between the jet and mesoscale eddies can maintain the decadal oscillation of the KE. The wind-driven SSHAs are broad-scale and very weak compared to the intrinsic variability. Physically they can potentially trigger delayed responses of the latter by modulating vorticity advection from upstream but the statistical significance is low. KE perturbations resulting from the intrinsic variability, on the other hand, could feedback onto the wind-driven SSHAs by inducing anomalous basin-scale wind stress. The KE jet is thus an integrated system involving the jet and the eddies, possibly feeding back to, and paced by, wind stress anomalies.

Iotivity Cloud-enabled Platform for Energy Management Applications

In developing countries today, population growth and the penetration of higher standard of living appliances in homes has resulted in a rapidly increasing residential load. In South Africa, the recent rolling blackouts and electricity price increase only highlighted this reality calling for sustainable measures to reduce the overall consumption and peak load. The dawn of the smart grid concept, embedded systems and ICTs have paved the way to novel HEMS design. In this regard, the Internet of Things (IoT), an enabler for smart and efficient energy management systems is seeing increasing attention for optimizing HEMS design and mitigate its deployment cost constraints. In this work, we propose an IoT platform for residential energy management applications focusing on interoperability, low-cost, technology availability and scalability. We focus on the backend complexities of IoT Home Area Networks (HAN) using the OCF IoTivity-Lite middleware. To augment the quality, servicing and reduce cost and complexities, this work leverages open-source Cloud technologies from Back4App as BaaS to provide consumer and Utilities with a data communication platform within an experimental study illustrating time and space agnostic “mind-changing” energy feedback, Demand Response Management (DRM) and appliance operation control via a HEM App via an Android smartphone.

Design of a Neural Super-Twisting Controller to Emulate a Flywheel Energy Storage System

In this work, a neural super-twisting algorithm is applied to the design of a controller for a flywheel energy storage system (FESS) emulator. Emulation of the FESS is achieved through driving a Permanent Magnet Synchronous Machine (PMSM) coupled to a shaft to shaft DC-motor. The emulation of the FESS is carried out by controlling the velocity of the PMSM in the energy storage stag and then by controlling the DC-motor velocity in the energy feedback stage, where the plant’s states of both electrical machines are identified via a neural network. For the neural identification, a Recurrent Wavelet First-Order Neural Network (RWFONN) is proposed. For the design of the velocity controller, a super-twisting algorithm is applied by using a sliding surface as the argument; the latter is designed based on the states of the RWFONN, in combination with the block control linearization technique to the control of the angular velocity from both machines in their respective operation stage. The RWFONN is trained online using the filtered error algorithm. Closed-loop stability analysis is included when assuming boundedness of the synaptic weights. The results obtained from Matlab/Simulink validate the performance of the proposal in the control of an FESS.