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1. TRANSIENT BIOBATTERIES: MICROFLUIDIC CONTROL FOR PROGRAMMABLE DISSOLUTION

   Mohammadifar, M. ; Choi, S. ( June 2018 , Technical digest SolidState Sensor Actuator and Microsystems Workshop)

   We report a simple approach to develop transient microbial fuel cells with the capability of dissolving in water after stable power generation within a programmed period. This novel water-soluble biobattery makes use of the integration of a dissolvable paper-based substrate, a simple pencil-drawn graphite anode, and a Prussian-blue (PB) cathode. The device features (i) a low cost transient paper-based platform, (ii) easily accessible electrode materials and simple fabrication steps and (iii) a time-controlled operation by using the number of serpentine microfluidic channels. The biobatteries reached to a maximum power of 0.5μW and a current 15.6μA and achieved full dissolution in less than 60 minutes. 

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2. Probabilistic Transient Stability Assessment of Power System Considering Wind Power Uncertainties and Correlations

   Yue, Ziyuan ; Liu, Yanli ; Yu, Yixin ; Zhao, Junbo ( January 2020 , International journal of power energy systems)

   This paper proposes a simple yet effective method for power system probabilistic transient stability assessment considering the wind farm uncertainties and correlations. Specifically, the inverse Nataf-transformation-based three-point estimation method and the Cornish-Fisher expansion have been integrated together to deal with the uncertainties and the correlations among different wind farms. Then, by resorting to the extended dynamic security region approach, the transient stability criterion is derived as a linear combination of nodal injection vector under a given fault condition. New indices for the identification of critical lines have also been developed. Extensive simulation results carried out on four different systems, including the practical GZ power system in China show that the computational efficiency of the proposed method is much higher than the Monte-Carlo-based method and other methods almost without the loss of accuracy. The effectiveness of the proposed method under different penetrations of wind power with different degree of correlations is also validated. It is shown that correlation among wind farms has a larger impact on the transient stability results with a higher penetration level of renewable energy. 

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3. Design and Evaluation of Fuzzy Adaptive Particle Swarm Optimization Based Maximum Power Point Tracking on Photovoltaic System Under Partial Shading Conditions

   https://doi.org/10.3389/fenrg.2021.712175  

   Guo, Liping ; Abdul, Nauman Moiz ( July 2021 , Frontiers in Energy Research)

   null (Ed.)

   Artificial intelligence methods such as fuzzy logic and particle swarm optimization (PSO) have been applied to maximum power point tracking (MPPT) for solar panels. The P-V curve of a solar panel exhibits multiple peaks under partial shading condition (PSC) when all modules of a solar panel do not receive the same solar irradiation. Although conventional PSO has been shown to perform well under uniform insolation, it is often unable to find the global maximum power point under PSC. Fuzzy adaptive PSO controllers have been proposed for MPPT. However, the controller became computation-intensive in order to adjust the PSO parameters for each particle. In this paper, fuzzy adaptive PSO-based and conventional PSO-based MPPT are compared and evaluated in the aspect of design and performance. A simple fuzzy adaptive PSO controller for MPPT was designed to reach the global optimal point under PSC and uniform irradiation. The controller combines the advantages of both PSO and fuzzy control. The fuzzy controller dynamically adjusts the PSO parameter to improve the convergence speed and global search capability. Since tuning of the PSO parameter is designed to be common for all particles, it reduced the computation complexity. The fuzzy controller’s rule base is designed to obtain a fast transient response and stable steady state response. Design of the fuzzy adaptive PSO-based MPPT is verified with simulation results using a boost converter. The results are evaluated in comparison to the results using a conventional PSO controller under PSC. Simulation shows the fuzzy adaptive PSO-based MPPT is able to improve the global search process and increase the convergency speed. The comparison indicates the settling time using the fuzzy adaptive PSO-based MPPT is 14% faster under PSC on average and 30% faster under uniform irradiation than the settling time using the conventional PSO. Both the fuzzy adaptive and conventional PSO controllers have similar output power tracking accuracy. 

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4. Timescales of glacial isostatic adjustment in Greenland: is transient rheology required?

   https://doi.org/10.1093/gji/ggae095  

   Pan, Linda ; Mitrovica, Jerry X. ; Milne, Glenn A. ; Hoggard, Mark J. ; Woodroffe, Sarah A. ( March 2024 , Geophysical Journal International)

   The possibility of a transient rheological response to ice age loading, first discussed in the literature of the 1980s, has received renewed attention. Transient behaviour across centennial to millennial timescales has been invoked to reconcile apparently contradictory inferences of steady-state (Maxwell) viscosity based on two distinct data sets from Greenland: Holocene sea-level curves and Global Navigation Satellite System (GNSS) derived modern crustal uplift data. To revisit this issue, we first compute depth-dependent Fréchet kernels using 1-D Maxwell viscoelastic Earth models and demonstrate that the mantle resolving power of the two Greenland data sets is highly distinct, reflecting the differing spatial scale of the associated surface loading: the sea-level records are sensitive to viscosity structure across the entire upper mantle while uplift rates associated with post-1000 CE fluctuations of the Greenland Ice Sheet have a dominant sensitivity to shallow asthenosphere viscosity. Guided by these results, we present forward models which demonstrate that a moderate low viscosity zone beneath the lithosphere in Maxwell Earth models provides a simple route to simultaneously reconciling both data sets by significantly increasing predictions of present-day uplift rates in Greenland whilst having negligible impact on predictions of Holocene relative sea-level curves from the region. Our analysis does not rule out the possibility of transient deformation, but it suggests that it is not required to simultaneously explain these two data sets. A definitive demonstration of transient behaviour requires that one account for the resolving power of the data sets in modelling the glacial isostatic adjustment process.

    

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5. Volumetric Rates of Luminous Red Novae and Intermediate-luminosity Red Transients with the Zwicky Transient Facility

   https://doi.org/10.3847/1538-4357/acc2b9  

   Karambelkar, Viraj R. ; Kasliwal, Mansi M. ; Blagorodnova, Nadejda ; Sollerman, Jesper ; Aloisi, Robert ; Anand, Shreya G. ; Andreoni, Igor ; Brink, Thomas G. ; Bruch, Rachel ; Cook, David ; et al ( May 2023 , The Astrophysical Journal)

   Luminous red novae (LRNe) are transients characterized by low luminosities and expansion velocities, and they are associated with mergers or common-envelope ejections in stellar binaries. Intermediate-luminosity red transients (ILRTs) are an observationally similar class with unknown origins, but they are generally believed to be either electron-capture supernovae in super-asymptotic giant branch stars or outbursts in dusty luminous blue variables (LBVs). In this paper, we present a systematic sample of eight LRNe and eight ILRTs detected as part of the Census of the Local Universe (CLU) experiment on the Zwicky Transient Facility (ZTF). The CLU experiment spectroscopically classifies ZTF transients associated with nearby (<150 Mpc) galaxies, achieving 80% completeness form_r< 20 mag. Using the ZTF-CLU sample, we derive the first systematic LRNe volumetric rate of${7.8}_{-3.7}^{+6.5}\times {10}^{-5}$Mpc⁻³yr⁻¹in the luminosity range −16 ≤M_r≤ −11 mag. We find that, in this luminosity range, the LRN rate scales as$\mathit{dN}/\mathit{dL}\propto L^{-2.5\pm 0.3}$—significantly steeper than the previously derived scaling ofL^−1.4±0.3for lower-luminosity LRNe (M_V≥ −10 mag). The steeper power law for LRNe at high luminosities is consistent with the massive merger rates predicted by binary population synthesis models. We find that the rates of the brightest LRNe (M_r≤ −13 mag) are consistent with a significant fraction of them being progenitors of double compact objects that merge within a Hubble time. For ILRTs, we derive a volumetric rate of${2.6}_{-1.4}^{+1.8}\times {10}^{-6}$Mpc⁻³yr⁻¹forM_r≤ −13.5 mag, which scales as$\mathit{dN}/\mathit{dL}\propto L^{-2.5\pm 0.5}$. This rate is ∼1%–5% of the local core-collapse supernova rate and is consistent with theoretical ECSN rate estimates.

    

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