Search Results (4,902)

Battery storage systems are becoming very popular around the world. However, they are mainly used in industry for high-performance applications. Domestic use is still sporadic due to size and cost issues. This work overviews basic conceptual designs for a cost-effective battery storage system. The main specificity of the proposed systems is the use of commonly available recycled batteries from household appliances such as laptops and backup power supplies. The circuit topology considered is a 3S (three cells in series) configuration. This is because such wiring arrangements are those that are most often found in the home appliances described here. The technical solutions of the device itself focus on the ratio of the efficiency of the whole system to the production cost. Given the above, attention was paid to the simulation analysis of the operating modes, which directly influenced the components’ price. Changing the switching control scheme of the power transistors makes it possible to reduce the requirements for the driving components used with minimal impact on the power conversion efficiency (Δη 1–4%). According to the established findings, a prototype was made on which the simulation findings were verified; then, we further focused on the experimental measurement of the efficiency of the MPPT converter and conducted an analysis of a methodology in which we measure the deviation from the actual point of maximum power. The simple possibility of parallelizing the individual storage devices will again help improve the system’s overall efficiency. This makes the system suitable for use in small spaces such as houses, garages, cellars, etc. Full article

In this research, we synthesized a series of Ti₃C₂T_x nanosheets with varying lateral dimensions and conducted a thorough investigation into the profound relationship between the electrochemical performance of Ti₃C₂T_x materials and their lateral sizes. This study innovatively incorporates a clever combination of small-sized and large-sized Ti₃C₂T_x nanosheets in the electrode preparation process. This strategy yields excellent results at low scan rates, with the fabricated electrode achieving a high volumetric capacitance of approximately 658 F/g. Even more remarkable is the fact that, even under extreme testing conditions where the scan rate surges to 10 V s⁻¹, the electrode retains its capacitive characteristics robustly without any significant performance degradation. These outstanding characteristics underscore the exceptional ability of Ti₃C₂T_x electrode materials to maintain high energy storage capacity during rapid charge–discharge cycles, holding significant importance for advancing the development of electrochemical energy storage devices with fast response times and high power densities. Full article

We establish a spherically symmetric model of solar atmosphere, which consists of the whole chromosphere and low corona below the 1.25 solar radius. It is a hydrodynamic model with heating in the chromosphere through an artificial energy flux. We performed a series of simulations with our model and found oscillations with a peak frequency of ∼4 mHz in the power spectrum. We confirmed that this resulted from the p-mode excited in the transition region and amplified in a resonant cavity situated in the height range ∼4×103–2×104 km. This result is consistent with global observations of Alfvénic waves in corona and can naturally explain the observational ubiquity of 4mHz without the difficulty of the p-mode passing through the acoustic-damping chromosphere. We also confirmed that acoustic shock waves alone cannot heat the corona to the observed temperature, and found mass upflows in the height range ∼7×103–7×104 km in our model, which pumped the dense and cool plasma into the corona and might be the mass supplier for solar prominences. Full article

This article, Queering Militarism in Israeli Photography, examines Adi Nes’s Soldiers series, a body of work that interrogates the intersections of queerness, militarism, and nationalism within Israeli society. By employing a distinctive “military circus” aesthetic, Nes challenges the rigid heteronormative and hyper-masculine archetypes embedded in Israeli military identity. His staged photographs depict soldiers in circus-inspired performative poses, blending military discipline with elements of the carnivalesque to subvert conventional representations of military masculinity. This approach creates spaces where queerness, vulnerability, and fluid identity defy the rigid confines of nationalist narratives. Using queer studies frameworks, performance theory, and postcolonial critique, this article analyzes Nes’s depiction of soldiers as both military subjects and circus performers, examining how these representations disrupt the “naturalness” of gender, power, and identity within the Israeli national ethos. Through a close reading of key images—such as the fire-breathing soldier, the acrobat on a tightrope, and the strongman figure—this article argues that Nes critiques homonationalism and exposes the co-optation of LGBTQ+ identities into militaristic frameworks. His images juxtapose exaggerated masculinity with homoerotic and introspective vulnerability, positioning the queer body as both a participant in and a subverter of the national narrative. Drawing on contemporary queer theory—including José Esteban Muñoz’s concept of “disidentification”, Eve Kosofsky Sedgwick’s theories of queer shame and performativity, and perspectives on temporality, failure, and counterpublics following Elizabeth Freeman, Jack Halberstam, Michael Warner, and Sara Ahmed—this article frames queerness as an active site of resistance and creative transformation within the Israeli military complex. The analysis reveals how Nes’s work disrupts Zionist masculinities and traditional militaristic structures through a hybrid aesthetic of military and circus life. By reimagining Israeli identity as an inclusive, multi-dimensional construct, Nes expands queer possibilities beyond heteronormative confines and homonationalist alignments. This merging of critical queer perspectives—from the destabilizing of discipline and shame to the public visibility of non-normative bodies—posits that queer identities can permeate and reshape state power itself, challenging not only the norms of militaristic nationalism but also the boundaries of Israeli selfhood. Full article

This manuscript aims to increase the utilization of solar energy, which is both environmentally friendly and easily accessible, to satisfy the energy needs of developing countries. In order to achieve this goal, maximum power generation should be provided from photovoltaic panels. Several maximum power point tracking (MPPT) methods are utilized for maximum power generation in photovoltaic panel systems under different weather conditions. In this paper, a novel intelligent hybrid fuzzy logic-controlled maximum power point tracking algorithm founded on the perturb and observe (PO) algorithm is presented. The proposed fuzzy logic controller algorithm and the incremental conductivity maximum power point tracking algorithm were simulated in a MATLAB(2018b version)/Simulink environment and evaluated by comparing the results. Four Sharp ND-F4Q295 solar panels, two in series and two in parallel, were used for the simulation. In this study, the voltage ripple of the proposed hybrid method was measured at 1% compared to the classical incremental conductivity method, while it was 8.6% in the IncCon method. Similarly, the current ripple was 1.08% in the proposed hybrid FLC method, while the current ripple was 9.27% in the IncCon method. It is observed that the proposed smart method stabilizes the system voltage faster, at 25 ms, in the event of sudden weather changes. Full article

Electric vehicles (EVs) are a sustainable means of transportation, with their onboard batteries being crucial for both performance and energy management. A modular and reconfigurable power converter topology to connect removable batteries to the main DC bus of an EV is proposed in this paper. By employing Dual Active Bridge (DAB) converters in an Input Parallel Output Series (IPOS) configuration, the proposed topology is compatible with 400 V and 800 V standards without the need for external switches. The research explored the possibility to apply a very simple control strategy based on independent linear regulators. A theoretical analysis of the IPOS DAB converter is presented and the design of independent control regulators which minimize the coupling effect between the control variables is addressed. The stability of the IPOS DAB converter could be ensured using the proposed simplistic approach, enabling us to drastically simplify the regulator design step. The dynamic performance of the system was confirmed by means of a simulation and experimentally. Full article

Electrical data analysis based on smart grids has become a fundamental tool used by electrical grid stakeholders to understand the energy consumption patterns of users, although many proposals in this area do not consider reactive energy as another source of useful information regarding distribution costs and threats to the grid. In this regard, the analysis of reactive energy patterns can become an extremely useful addition to existing electrical data analysis frameworks. This work shows the application of a series of clustering techniques over measurements of both active and reactive energy consumption measured for end users from the Colombian electrical network, including an analysis of the efficiency of the network measured by calculating the ratio of active energy to total consumption (power factor) per user. This allows a detailed characterization of users to be compiled, based on the identification of different active and reactive energy consumption behaviors, which could help grid operators to improve overall grid management and to increase the efficiency of their reactive energy compensation strategies. Full article

A Hertz radiator’s Sommerfeld boundary value problem is considered for the case when its electric moment is directed horizontally relative to the plane interface between two media with different values of magnetic permeability. An integral representation of the exact expression for the Hertz potential, which generalizes the classical solution for non-magnetic media, both in cylindrical and spherical coordinate systems, is obtained. The corresponding expressions for the scattered wave fields are given in the form of Sommerfeld integrals. It is shown that the potential components can be represented as the sum of an infinite series in powers of the Green function. Full article

This study has determined the period of sedimentation of the Lingshui Formation as the Oligocene (Rupelian-Chattian) through biostratigraphic data, including planktonic foraminifera zonation. The astronomical timescale framework for the Lingshui Formation was accurately constructed by integrating geophysical logging data and employing a multidisciplinary approach that includes time series analysis, cyclostratigraphy, astronomical dating, and Power Ratio Accumulation (PRA) methods. Sensitivity analysis of PRA has shown that natural gamma (GR) is the optimal paleoclimatic proxy, laying the foundation for subsequent analyses. The optimal sedimentation rate for the Lingshui Formation, determined by combining the coefficient of correlation (COCO) method with PRA analysis, is 5–5.4 cm/kyr. The duration of the Lingshui Formation was established at 5.02 Ma (28.52 Ma–23.5 Ma) based on time series analysis and astronomical tuning. The sediment noise model has revealed that the ~1.2 Myr obliquity modulation period has a significant impact on sea-level changes, further confirming the stratigraphic control of astronomical forcing on the sedimentation rate of the Lingshui Formation. This study establishes a high-precision astronomical timescale framework for the Lingshui Formation and provides a robust methodology, offering scientific basis for the research in astronomical chronostratigraphy and cycle stratigraphy, which has significant potential implications. Full article

To avoid additional component losses while significantly improving the energy conversion efficiency of battery energy storage systems, the application of series-connected partial power converter (S-PPC) technology in battery energy storage systems is investigated in this study. In the S-PPC battery energy storage system configuration, coupling effects exist between the dc-link side and the battery-series side. The impedance modeling of a battery energy storage system is performed while taking these coupling effects into consideration. To address the instability observed during battery discharge conditions, an impedance reshaping control strategy that is suitable for the S-PPC battery energy storage system is proposed. The proposed method focuses on adjusting the input impedance of the load converter within a limited frequency band centered on the system’s oscillation frequency. This targeted approach significantly improves the stability of the system while ensuring ease of implementation and maintaining high reliability. Finally, the experimental results validate the theoretical analysis. Full article

The transition to renewable energy sources is vital for achieving sustainability, and photovoltaic (PV) systems play a key role in this shift. However, their performance can be significantly affected in snowy conditions, where the irradiation and energy production are limited. This study addresses a critical gap in the literature by developing a MATLAB/Simulink model that considers the impacts of snow layering and removal on roof-mounted photovoltaic arrays. This study investigates various module interconnection schemes—including Series, Series-Parallel, Total-Cross-Tied, Bridge-Linked, and Honey-Comb—to determine their impact on energy efficiency in snowy environments. Based on the results, when the modules are fully covered by uniform snow, the power losses can increase from 38.9% to 93.2% for all interconnection schemes by increasing the accumulated snow from 1 cm to 5 cm. When the modules are covered by nonuniform snow and the snow removal is considered the TCT scheme has the minimum power losses and the maximum efficiency, depending on the accumulated snow pattern. For the worst scenario, the power loss is 70.1% for TCT, 71.7% for SP, 72% for HC, 72.3% for BL, and 76.7% for series interconnection. For the other scenarios, almost a similar trend can be observed where the TCT interconnection has the maximum efficiency, and the series interconnection has the minimum efficiency. Full article

The corrosion fatigue of duplex stainless-steel X2CrNiMoN22-5-3 can be determined by purely alternating axial cyclic load to failure using hour-glass shaped specimens. The experimental setup comprises a corrosion chamber allowing for the circulation of an aquifer electrolyte heated to 369 K simulating a carbon capture and storage as well as geothermal power plant environment. During engineering of a carbon storage site or geothermal power plant, it may be crucial to determine the failure onset of a component beforehand. Therefore, an algorithm with 93.3% reliability was established based on splitting the measured potential values into ten time series with a capacity of ten values. The failure of corrosion fatigue specimens in a geothermal environment correlates to the drop of the curves of the electrochemical potential which is measured simultaneously within the corrosion chamber. Crack initiation was, therefore, successfully derived from the electrochemical potential. Full article

NiO_x is a p-type semiconductor with excellent stability, which makes it interesting for a wide range of applications. Broadband photodetectors with high responsivity (R) were fabricated by depositing r.f.-sputtered NiO_x layers on n-Si at room temperature (RT), 50 °C and 100 °C. In self-powered mode the RT diodes have R between 0.95 and 0.39 A/W for wavelengths between 365 and 635 nm, while at a reverse bias of −4 V, the responsivity increases to values between 22 A/W and 10.7 A/W for wavelengths in the same range. The increase of the deposition temperature leads to a decrease of R but also to a smaller reverse dark current. Thus, the 100 °C photodiodes might be more appropriate for applications where high responsivity is required, because of their smaller power consumption compared to the RT diodes. In addition, it was found that the increase of the deposition temperature leads to an increase of the diodes’ series resistance and the resistivity of NiO_x. The effect of Rapid Thermal Annealing (RTA) on the properties of the photodiodes was studied. Annealing at 550 °C for 6 min leads to much higher responsivity compared to R of diodes with as-deposited NiO_x. However, a disadvantage of the annealed diode is that the reverse current depends on the amplitude and polarity of previously applied bias voltage. The higher responsivity of the RTA photodiodes makes them useful as light sensors. Full article

Fuel cells (FCs) offer several operational advantages when integrated as a power source in electric vehicles (EVs). Since the voltage of these cells is typically low, usually less than 1 V, the power conversion system requires a DC–DC converter capable of providing a high voltage conversion ratio to match the input voltage of the motor propulsion system, which can exceed 400 V and reach up to 800 V. The modular DC–DC boost converter proposed in this paper is designed to achieve a high voltage step-up ratio for the input FC voltages through the use of isolated series-connecting boosting submodules connected. The power electronic topology employed in the submodules (SMs) is designed to provide a flexible output voltage while maintaining a continuous input current from the fuel cells with minimal current ripple to improve the FC’s performance. The proposed step-up modular converter provides several benefits including scalability, better controllability, and improved reliability, especially in the presence of partial faults. Computer simulations using MATLAB/SIMULINK^® software (R2024a) have been used to study the feasibility of the proposed converter when connected to a permanent magnet synchronous motor (PMSM). Also, experimental results using a 1 kW prototype composed of four SMs have been obtained to validate the performance of the proposed converter. Full article

This paper investigates the stability mechanisms and suppression strategies for sub-synchronous oscillations (SSOs) in hybrid wind farms (HWFs) consisting of doubly-fed induction generator (DFIG) and permanent magnet synchronous generator (PMSG)-based wind turbines. To address the challenges in mitigating SSOs due to the complex interactions between the generators in hybrid wind farms, as well as external and parameters disturbances, a state-space model of the HWF is developed to capture the impact of external disturbances and parameter uncertainties on system dynamics. Through eigenvalue and participation factor analyses, this paper examines the effects of uncertainties in voltage control parameters, grid line series compensation, and the fluctuating power outputs of DFIGs and PMSGs on SSO behavior. A robust SSO suppression controller based on H_∞ theory is proposed, demonstrating a substantial reduction in harmonic distortion and improved settling time compared to conventional control strategies under varying disturbances. The simulation results show that the proposed controller significantly enhances the system’s resilience to disturbances and uncertainties, effectively mitigating SSO and improving overall system stability. Full article