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The flat design of security and stability control system (SSCS) can realize the information interaction between each control sub-station and each sub-grid,which is conducive to reducing the number of SSCS layers and improving its reliability,thus increasing the difficulty of searching the control paths and differentiating the vulnerable components. The bidirectional/loop communication channels are added to the tree-shape SSCS to reduce the intermediate stations and find all the paths from the top to bottom stations based on the adjacent matrix. Considering availability of components and controllable capacity of underlying stations,the control capability of the flat SSCS is newly quantified. Average control ability and average associated path number are defined to evaluate the influence of flattening on the control ability of each station. Analytical sensitivity model of the control capability of flat SSCS with respect to the components' availability is proposed to determine the vulnerable components. The numerical analysis shows that the flat design reduces levels and intermediate stations,and improves the controllability of the SSCS. The impact on the controllability of the SSCS increases by the number of paths and controllable power,but decreases by the number of layers.

The Pamir, situated in central Asia, is a result of the ongoing northward advance of the Indian continent, leading to compression of the Asian landmass. While geodetic and seismic data typically indicate that the most significant deformation in Pamir is along its northern boundary, an Mw 7.2 earthquake on 7 December 2015 and an Mw 6.8 earthquake on 23 February 2023 have occurred in the remote interior of Pamir. These two Mw ≥ 6.5 earthquakes, with good observations of satellite synthetic aperture radar data, provide a rare opportunity to gain insights into rupture mechanics and deformation patterns in this challenging-to-reach region. Here, we utilize spaceborne synthetic aperture radar data to determine the seismogenic faults and finite slip models for these two earthquakes. Our results reveal that the 2015 earthquake ruptured a ~88 km long, left-lateral strike-slip fault that dips to northwest. The rupture of the 2015 earthquake extended to the ground surface over a length of ~50 km with a maximum slip of ~3.5 m. In contrast, the 2023 earthquake did not rupture the ground surface, with a maximum slip of ~2.2 m estimated at a depth of ~9 km. Notably, the seismogenic fault of the 2015 earthquake does not align with the primary strand of the Sarez–Karakul fault system (SKFS), and the 2023 earthquake occurred on a previously unmapped fault. The well-determined seismogenic faults for the 2015 and 2023 earthquakes, along with the SKFS and other distributed faults in the region, suggest the existence of a wide shear zone extending from south to north within the central Pamir. [ABSTRACT FROM AUTHOR]

The 2019 M w 7.1 Ridgecrest earthquake opens an opportunity to investigate how soon we can produce a reliable fault geometry and subsequently a robust source model based on high-rate Global Positioning System (GPS) data. In this study, we conduct peak ground displacement (PGD) magnitude scaling, real-time centroid moment tensor (CMT) calculation and rapid kinematic slip inversion. We conclude that a four-station PGD warning with a magnitude of M w 7.03 can be issued at 24 s after initiation of the rupture. Fast CMT inversion can initially recover the correct nodal planes at 30 s. The kinematic slip model reveals that the M w 7.1 earthquake is a predominant dextral strike-slip event with both normal and thrust components resolved. The earthquake shows a bilateral rupture with a low propagation speed of ∼2.1 km s−1 and a slip maxima of ∼4 m. The total moment is 5.18 × 1019 N m (M w 7.11). We further suggest that a reasonable source model will be available in a simulated real-time mode within 30 s after the earthquake occurring, without using full high-rate GPS waveforms. This research highlights the significance of high-rate GPS for rapid earthquake response and modelling of kinematic rupture, which is also generalized by the hypothetical real-time GPS analysis for the 2016 M w 7.8 Kaikoura earthquake and the 2010 M w 7.2 El Mayor-Cucapah earthquake. [ABSTRACT FROM AUTHOR]

Although the Papuan fold and thrust belt (PFTB) is thought to accommodate convergence between the Pacific and Australian plates, the possible strain partitioning and its kinematic controls in the region are poorly understood. On 25 February 2018, a devastating Mw 7.5 earthquake jolted the southern area of the PFTB, central Papua New Guinea. The detailed imaging of the source parameters of this large earthquake is an urgent demand for a better understanding of the tectonism in the region. Here we used spaceborne interferometric synthetic aperture radar data to carefully determine the possible ruptured faults and associated fault geometries and further estimated the detailed slip of the 2018 Mw 7.5 earthquake. We find that the earthquake involved multiple faults failure, and a four‐segment fault model can reasonably produce the complex coseismic deformation, especially the observed bimodal displacements. The earthquake was dominated by reverse fault motion, and significant slip of up to ~0.7 m was documented on faults extending at depths great than 25 km. An integrated analysis of the fracture complexities suggests that possible strain partitioning in the PFTB could be tightly coupled with regional fault geometries and lithospheric properties. Our findings on the deep brittle failures suggest that crustal shortening across the PFTB could primarily control the growth of fold and thrust belt in the central Papua New Guinea. Key Points: Complete coseismic surface deformation generated from InSAR helps determine ruptured faults and constrain the complex source parametersThe 2018 Mw 7.5 Papua New Guinea earthquake was characterized by deep‐seated reverse faulting with ruptures extending into depths of 25 kmThis event revealed the possible strain partitioning in the Papuan fold and thrust belt and can help explain its growth [ABSTRACT FROM AUTHOR]

The M w 7.6 Chi-Chi earthquake struck central western Taiwan in 1999. The rupture was complex with several dislocations along the 100-km long Chelungpu thrust fault. Revisiting this earthquake is a challenge, as the precision and coverage of the data sets available are quite poor. Furthermore, the topographic and vegetation coverage complexity of the area prevents coherent radar images. In this paper, radar and optical images, and terrestrial geodetic measurements, were utilised to study the fault. The Particle Swarm Optimization and Okada Inversion (PSOKINV) geodetic inversion package was used with the generalized Akaike's Bayesian Information Criterion (gABIC) to precisely determine the slip distribution and relative weighting of datasets. Differences in results using the data sets jointly or separately (e.g., under-estimation due to InSAR, inconsistencies in SPOT offsets, smoother slip distribution with gABIC weighting) are observable. Most of the energy was released in the northern part of the fault, where the strike veers toward the east, and mainly at depths less than 4 km. The PSOKINV-gABIC approach is viable for the study of complicated cases such as the Chi-Chi earthquake and can significantly benefit the weight determination and physical realism of the fault geometry. [ABSTRACT FROM AUTHOR]

Satellite radar imagery can record surface deformation over a wide range in both phase and amplitude formats, with Interferometric Synthetic Aperture Radar (InSAR) achieving millimetre accuracy. Based on these satellite radar observations, landslide detection at a large scale can be enhanced, which is beneficial to landslide risk assessment and disaster mitigation. However, there are still several challenges in the landslide detection with satellite radar observations. This talk presents an automated SAR-based landslide detection system under development which addresses the five main challenges of conventional InSAR for landslide detection.The first challenge is dense vegetation that affects the coherence of SAR data. The effects can be weakened by use of SAR imagery with a long wavelength (e.g. S-band or L-band), a short temporal resolution, and/or a high spatial resolution (e.g. 1 m or even higher), and/or advanced InSAR time series. The second challenge is to deal with landslides with large deformation gradients, which can be addressed by SAR offset tracking and range split-spectrum interferometry (RSSI) methods with relatively low precision. We have developed an integrated approach to combine the RSSI and conventional InSAR to capture the large surface displacements of fast-moving landslides more precisely. Atmospheric effects represent another challenge of conventional InSAR for landslide detection, especially in mountain areas. The Generic Atmospheric Correction Online Service (GACOS) developed at Newcastle University is used to reduce atmospheric effects on radar observations and simplify the following time series analysis. The fourth challenge is the impacts of SAR geometry such as shadow and layover. The impacts can be pre-analysed using a high-resolution external DEM. Since very high-resolution (VHR) DEMs are often not available whilst processing VHR radar images (e.g. 1m or higher TerraSAR-X), a machine learning approach has been developed to identify water bodies, shadow and layover areas. The geometry impacts can be weakened with the joint use of descending and ascending tracks, different tracks with different incidence angles, or radar images from different radar missions. The fifth challenge is topographic effects in areas with high buildings or steep slopes, which could easily lead to phase unwrapping errors. A baseline linear combination approach has been developed to address it. In our automated SAR-based landslide detection system under development, the GACOS-assisted InSAR time series technique is employed to delimit deformation acceleration zones and detect extremely-slow-to-slow moving landslides. SAR offset tracking and RSSI are used in parallel to capture large displacements and detect moderate-to-fast moving landslides. Machine learning algorithms are developed to automatically map post-event landslides triggered by earthquakes or heavy rains. [ABSTRACT FROM AUTHOR]

In recent years, the usage of new technologies in distributed generation is growing due to the electricity industry movement towards privatization and decentralized production of electric energy as well as competition among the new technologies. Microgrids are practical examples of the concept of decentralized production. Also, the employment of renewable energies is rapidly promoted due to the construction barriers of conventional power plants. Therefore, selecting and applying the appropriate technologies in planning and careful design of the type and capacity of generation and energy storage units are important. This paper proposed a robust model for day-ahead production scheduling of electrical and thermal units in a large-scale virtual power plant comprising a large number of distributed generation units and consumers accompanied by energy storage. To consider real conditions, the uncertainty of electrical demands is modeled by employing scenario-based analysis and probabilistic programming. So, five scenarios are created and modeled. In addition, two operation mode of a microgrid is considered connected and islanded modes. The objective function consists of total profit resulting from the daily operation of all units. The results confirm the applicability and effectiveness of the proposed model. Moreover, the total profit of the connected mode of the microgrid is about 20% more than the islanded mode, in all scenarios, and the cumulative profit cash flow of the connected mode is about 31% more than islanded mode. [ABSTRACT FROM AUTHOR]

Functional groups and small-molecule organic matter are two key parts of coal. To explore the microscopic mechanism underlying the synergistic effect of both parts on methane adsorption, the oxygen-containing (-OH, -COOH, and -C=O) and nitrogen-containing (-NH 2 ) functional groups and two common small molecular organic matter methylbenzene and tetrahydrofuran-2-alcohol in coal are selected. The quantum chemical meta-GGA functional method is used to optimize all structures. The electrostatic potential analyses, weak interaction analyses, and theory of atoms in molecules have been used to delve further into the nature of this synergistic effect. Our results show that functional groups inhibit methane adsorption by coal molecules, and the inhibition effect is enhanced in the presence of methylbenzene. Interestingly, the synergistic effects between functional groups and small molecular organic matter are changed from inhibition to promotion after introducing tetrahydrofuran-2-alcohol, wherein -COOH has the best synergistic effect. This work not only offers a theoretical foundation for exploring the synergistic effect of small molecular organic matter and functional groups on methane adsorption by coal molecules but also lays a foundation for further research on gas prevention and extraction., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

Formation of solid solutions is a good strategy to acquire materials with special properties and bring forth new type of applications or enhance the performance of currently existing devices. In this study, hollow ZnxCd1-xS nanospheres with different molar ratios were synthesized via a facile hydrothermal process. The products were fully characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and UV-vis absorption spectroscopy. It was found that the photocatalysis performance of the as-prepared samples could be enhanced by formation of ZnxCd1-xS solid solutions. In addition, their photocatalytic activities are dependent on the Zn/Cd molar ratios and nanostructures of ZnxCd1-xS solid solutions. Hollow Zn0.2Cd0.8S spheres exhibit extremely high photocatalytic activity and good re-usability, and the photocatalytic conversion of RhB reaches as high as 96% after 50 min of irradiation.