Search

We theoretically analyze the electronic transport properties of a monolayer graphene/insulator/superconductor (G I S) tunnel junction subject to a temperature gradient. For intrinsic graphene, the system shows always dissipative charge transport even in the presence of an electronic temperature difference between the two leads. Differently, the G I S produces a thermoelectric response when the graphene electrochemical potential is lifted to energies comparable to the zero-temperature gap of the superconductor, i.e., the system is particle–hole asymmetric. Indeed, the thermally biased G I S system is able to produce both a short-circuit Peltier current and an open-circuit Seebeck voltage. This thermoelectric effect is made of a linear conventional component, due to the intrinsic particle–hole asymmetry of the system, and a non-linear contribution, due to a further spontaneous particle–hole symmetry breaking. In most of the thermal and charge configurations of the G I S system, the linear component prevails. Concluding, the G I S system could be employed in the design of thermometers, electromagnetic radiation sensors, and heat engines with profound influence in superconducting quantum technologies. [ABSTRACT FROM AUTHOR]

Tin-based perovskite solar cells are expected to replace lead-based perovskite solar cells to achieve environmentally friendly devices. Currently, a significant challenge lies in low filling factor and short-circuit current density, leading to an overall lower efficiency of these cells. In this context, we conducted a comprehensive comparative study on the deposition of these three inorganic small-molecule materials (CsBr, CsCl, CsI) on tin-based perovskite layers. The results showed that depositing these three inorganic small-molecule materials (CsBr, CsCl, CsI) on tin-based perovskite layers can improve the topography of the thin film and display an increased grain size. Simultaneously, the presence of the passivation layer facilitates preferred crystal orientation and enhanced charge carrier transport capabilities. Furthermore, devices with passivation layers exhibit reduced series resistance and increased shunt resistance, leading to a higher filling factor, a higher short-circuit current density, and a reduced leakage current in the passivated devices. This results in an elevated overall conversion efficiency of the devices. Notably, among the three halide materials employed for passivation, CsI demonstrates the most effective passivation, with the champion device achieving an efficiency of 6.0%. This study contributes valuable insights into the passivation strategies for tin-based perovskite solar cells. [ABSTRACT FROM AUTHOR]

An analytical device physics model is presented for determining the energy conversion efficiency of semiconductor nanowire array-based radial (core–shell) p-i-n junction betavoltaic cells for two- and three-dimensional radioisotope source geometries. Optimum short-circuit current density J sc , open-circuit voltage V oc , fill factor F F , and energy conversion efficiency η are determined for various nanowire properties, including dopant concentration, nanowire length, core diameter, and shell thickness, for Si, GaAs, and GaP material systems. A maximum efficiency of 8.05 % was obtained for GaP nanowires with diameter 200 nm (p-core diameter, i-shell, and n-shell thicknesses of 24, 29.4, and 58.6 nm, respectively), length 10 μ m , acceptor and donor concentrations of 10 19 and 5 × 10 18 cm − 3 , respectively, and a 3D source geometry. [ABSTRACT FROM AUTHOR]

We investigate microlenses that selectively focus the light on only a small fraction of all nanowires within an arrayed InP nanowire solar cell. The nano-concentration improves both the short-circuit current (J s c ) and the open-circuit voltage (V o c ) of the solar cell. For this purpose, polymethyl methacrylate microlenses with 6 μm diameter were randomly positioned on top of an arrayed nanowire solar cell with 500 nm pitch. The microlenses were fabricated by first patterning cylindrical micropillars, which were subsequently shaped as lenses by using a thermal reflow process. The quality of the microlenses was experimentally assessed by Fourier microscopy showing strong collimation of the emitted photoluminescence. By analyzing the slope of the integrated photoluminescence vs excitation density, we deduce a substantial enhancement of the external radiative efficiency of a nanowire array by adding microlenses. The enhanced radiative efficiency of the lensed nanowire array results in a clear enhancement of the open-circuit voltage for a subset of our solar cells. The microlenses finally also allow to increase the short-circuit current of our relatively short nanowires, providing a route to significantly reduce the amount of expensive semiconductor material. [ABSTRACT FROM AUTHOR]

[Display omitted] The interfacial interaction of carbon nanotubes (CNTs) significantly enhances the output capability of piezoelectric nanogenerators (PENGs). However, overcoming the limitation of low specific surface area in one-dimensional materials remains a significant challenge. This paper introduces a hydrothermal method for composite MOF (C-M) using CNTs and MOF-5, demonstrating localized co-doping between them. Coaxial electrospun piezoelectric fiber membranes (C-MNF) were then prepared using PVDF/PAN as the matrix. Benefiting from C-M's excellent crystallinity and its synergistic interaction with the polymer matrix, the C-MNF-based PENG showed a 125 % increase in output voltage, reaching ∼25 V, compared to coaxial membranes simply mixing MOF-5 and CNTs. As a result, its short-circuit current was ∼1.8 μA, with a piezoelectric coefficient d 33 of ∼400 pC N−1. Consequently, this material exhibits superior piezoelectric output capabilities, paving the way for future functional material fabrication. [ABSTRACT FROM AUTHOR]

Non-toxic molecular ferroelectrics have attracted significant interest due to their unique flexibility, low costs, and environmental friendliness. However, such materials with narrow bandgaps and ferroelectricity above room temperature (RT) are still scarce. Herein, we present a brand-new lead-free molecular ferroelectric [C8N2H22]1.5[Bi2I9] synthesized hydrothermally. [C8N2H22]1.5[Bi2I9] features a zero-dimensional (0D) structure with a polar space group of Pc, as confirmed by single-crystal X-ray diffraction and second-harmonic generation (SHG) analyses. The RT hysteresis loop reveals the intrinsic ferroelectricity of [C8N2H22]1.5[Bi2I9] with a spontaneous polarization (Ps) of 1.3 μC cm−2. A visible-light optical bandgap has been confirmed by UV-vis spectroscopy and theoretical calculations. A notable ferroelectric photovoltaic (PV) effect has been revealed in [C8N2H22]1.5[Bi2I9]-based photoelectric devices with an open-circuit voltage (Voc) of 0.39 V and a short-circuit current density (Jsc) of 2.3 μA cm−2 under AM 1.5G illumination. The PV performance can be significantly enhanced by tuning the ferroelectric polarization, achieving a maximum Voc of 0.47 V and Jsc of about 50 μA cm−2. This study offers a novel member of the 0D lead-free hybrid organic–inorganic molecular ferroelectric family possessing great promise for optoelectronic devices. [ABSTRACT FROM AUTHOR]

Non-toxic molecular ferroelectrics have attracted significant interest due to their unique flexibility, low costs, and environmental friendliness. However, such materials with narrow bandgaps and ferroelectricity above room temperature (RT) are still scarce. Herein, we present a brand-new lead-free molecular ferroelectric [C8N2H22]1.5[Bi2I9] synthesized hydrothermally. [C8N2H22]1.5[Bi2I9] features a zero-dimensional (0D) structure with a polar space group of Pc, as confirmed by single-crystal X-ray diffraction and second-harmonic generation (SHG) analyses. The RT hysteresis loop reveals the intrinsic ferroelectricity of [C8N2H22]1.5[Bi2I9] with a spontaneous polarization (Ps) of 1.3 μC cm−2. A visible-light optical bandgap has been confirmed by UV-vis spectroscopy and theoretical calculations. A notable ferroelectric photovoltaic (PV) effect has been revealed in [C8N2H22]1.5[Bi2I9]-based photoelectric devices with an open-circuit voltage (Voc) of 0.39 V and a short-circuit current density (Jsc) of 2.3 μA cm−2 under AM 1.5G illumination. The PV performance can be significantly enhanced by tuning the ferroelectric polarization, achieving a maximum Voc of 0.47 V and Jsc of about 50 μA cm−2. This study offers a novel member of the 0D lead-free hybrid organic–inorganic molecular ferroelectric family possessing great promise for optoelectronic devices. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) perovskites are promising for photovoltaic applications due to their outstanding optical properties and better environmental stability compared to three-dimensional (3D) perovskites. Unlike 2D Ruddlesden–Popper (RP) perovskites, which use monovalent ammonium spacers, Dion–Jacobson (DJ) perovskites employ divalent organic spacers that enhance structural stability by mitigating weak van der Waals interactions. However, the random phase distribution and disorder crystal orientation in 2D DJ perovskites create deep quantum wells, hindering charge transfer and reducing short-circuit current density (JSC) and overall photovoltaic performance. This study introduces an organic diammonium, 1,4-butanediamine diacetate (BDAAc2), to replace the traditional halide spacer 1,4-butanediamine iodide (BDADI2). This substitution regulates perovskites crystallization dynamics, reducing compositional disorder and random phase distribution, thus improving the quality of the perovskite films. The robust coordination interactions between BDAAc2 and the perovskite inorganic framework lead to an ordered [PbX6]4− arrangement, suppressing the formation of complex intermediate phases and significantly enhancing δ phase crystallinity in the intermediate film. This results in a high yield of high-quality α phase. Consequently, the resulting 2D DJ perovskite solar cells based on BDAFA3Pb4(I0.9Br0.1)13 achieve a higher power conversion efficiency of 16.41% and an elevated JSC of 20.46 mA cm−2. [ABSTRACT FROM AUTHOR]

As quantum computing hardware becomes more complex with ongoing design innovations and growing capabilities, the quantum computing community needs increasingly powerful techniques for fabrication failure root-cause analysis. This is especially true for trapped-ion quantum computing. As trapped-ion quantum computing aims to scale to thousands of ions, the electrode numbers are growing to several hundred, with likely integrated photonic components also adding to the electrical and fabrication complexity, making faults even harder to locate. In this work, we used a high-resolution quantum magnetic imaging technique, based on nitrogen-vacancy centers in diamond, to investigate short-circuit faults in an ion trap chip. We imaged currents from these short-circuit faults to ground and compared them to intentionally created faults, finding that the root cause of the faults was failures in the on-chip trench capacitors. This work, where we exploited the performance advantages of a quantum magnetic sensing technique to troubleshoot a piece of quantum computing hardware, is a unique example of the evolving synergy between emerging quantum technologies to achieve capabilities that were previously inaccessible. [ABSTRACT FROM AUTHOR]

Insulated gate bipolar transistors (IGBTs) serve as the pivotal components within power conversion systems, and given the harsh conditions they endure, evaluating their aging is of paramount importance. Traditional offline aging monitoring method are relatively complex. Based on the conduction voltage drop as the characteristic quantity of IGBT aging, a simpler technique for extracting this parameter is presented, facilitating the assessment of IGBT aging status. Incorporating the working principle of the IGBT bridge‐arm short‐circuit, a conduction voltage drop model has been established. A composite aging electrical parameter is used to eliminate the impact of degradation in the bond wire of the current source device. By engineering a closed‐loop gate drive circuit with adjustable voltage, the short‐circuit current is maintained constant, thereby facilitating the acquisition of a consistent conduction voltage drop. A conduction voltage extraction circuit is proposed, in which a resistance‐capacitance discharging time is equivalent to the conduction voltage drop to replace the analogue‐to‐digital circuit. By decreasing the amount of active zone of the chip in IGBT module for increased conduction voltage drop to simulate aging state, the proposed method with the driving circuit is experimentally validated as feasible and reliable. [ABSTRACT FROM AUTHOR]

In heavily loaded regional power grids, some AC transmission lines are confronting escalating pressures due to excessive short-circuit currents. To optimize AC channels, most research advocates for retrofitting existing AC lines into multi-line-commutated converter-based high-voltage direct current (LCC-HVDC) lines. However, there is a contradiction between limited land area for AC stations and the relatively large footprint of passive filters in LCC-HVDC; this paper introduces self-adapted LCC (SLCC) by replacing passive filter groups with a static var generator (SVG). Secondly, the reactive power compensation, harmonic filtering control methods of SVGs, and operation characteristics of the SLCC system are explored, and the harmonics of the grid-side current are reduced by nearly 14.6%. Then, to fill the gap of previous studies on solely AC or AC-DC line touching, inspired by emerging DC line-touching risks in double-circuit (LCC and SLCC) lines on the same tower, the equivalent models are formulated to elucidate the evolution mechanisms of voltage/current and extract fault features in various line-touching faults; it finds that the longitudinal differential current during line-touching faults can be capitalized. Based on the current feature, an effective protection algorithm tailored for the identification of DC line-touching faults is proposed. Finally, simulations are conducted to validate the efficacy of proposed control and protect methods, demonstrating the potential to enhance the reliability of AC to DC conversion projects. [ABSTRACT FROM AUTHOR]

Faormamadinium based perovskites have been proposed to replace the methylammonium lead tri-iodide (MAPbI3) perovskite as the light absorbing layer of photovoltaic cells owing to their photo-active and chemically stable properties. However, the crystal phase transition from the photo-active α -FAPbI3 to the non-perovksite δ -FAPbI3 still occurs in un-doped FAPbI3 films owing to the existence of crack defects, which degrads the photovoltaic responses. To investigate the crack ratio (CR)-dependent structure and excitonic characteristics of the polycrystalline FAPbI3 thin films deposited on the carboxylic acid functionalized ITO/glass substrates, various spectra and images were measured and analyzed, which can be utilized to make sense of the different devices responses of the resultant perovskite based photovoltaic cells. Our experimental results show that the there is a trade-off between the formations of surface defects and trapped iodide-mediated defects, thereby resulting in an optimal crack density or CR of the un-doped α -FAPbI3 active layer in the range from 4.86% to 9.27%. The decrease in the CR (tensile stress) results in the compressive lattice and thereby trapping the iodides near the PbI6 octahedra in the bottom region of the FAPbI3 perovskite films. When the CR of the FAPbI3 film is 8.47%, the open-circuit voltage (short-circuit current density) of the resultant photovoltaic cells significantly increased from 0.773 V (16.62 mA cm−2) to 0.945 V (18.20 mA cm−2) after 3 d. Our findings help understanding the photovoltaic responses of the FAPbI3 perovskite based photovoltaic cells on the different days. [ABSTRACT FROM AUTHOR]

In the present study, a triphasic-based system was prepared using constituents such as Lanthanum Calcium Manganite (LCM) , Cobalt Ferrite (CF) , and Barium Titanate (BT) in different proportions. The composition (1-x)LCM: x(0.7CF-0.3BT) , where x = 0, 0.1, 0.2, 0.3, and 1, was employed to produce the triphasic system-based materials using a solid-state reaction technique. X-ray diffraction results confirmed the development of the triphasic phase in the composites through the JCPDS card number of the major peaks. The average crystallite size calculated from XRD data was found to vary with increasing 0.7CF-0. 3 BT concentration in LCM. FTIR spectroscopy indicates alterations in the main peaks with an increase in content of 0.7CF-0.3BT , suggesting the formation of triphasic composites. The upward trend in dielectric permittivity suggests the successful occurrence of Maxwell-Wagner polarization, indicating relaxor behavior at lower frequency values. Impedance spectroscopy reveals dielectric relaxation and the contribution of charge carriers in triphasic composites, along with the impact of grain and grain boundaries. Magnetization analysis at room temperature approves an increase in saturation magnetization in composites i.e., 0.7LCM-0.3(0.7CF-0. 3 BT) triphasic material exhibiting a maximum saturation magnetization of 13.04 emu/g. Magnetoelectric behaviour is observed in triphasic materials at different AC magnetic fields. The 0.9LCM-0.1(0.7CF-0.3BT) triphasic hydroelectric cell achieved a peak current of 1.29 mA and showed enhanced stability over time. Its I-V characteristics revealed a short-circuit current of 3.5 mA, an open-circuit voltage of 0.85 V, and an off-load power output of 2.97 mW. The triphasic system demonstrates improved structural, electrical, and hydroelectric cell (HEC) performance offering promising prospects for use in magnetoelectric and hydroelectric devices. [ABSTRACT FROM AUTHOR]

Doping engineering has been applied in niobium-doped NiO (NiO:Nb) by adding nitrogen (N) in its structure. The rf-sputtered films were made from a Ni-Nb composite target on unheated substrates at 300 W rf power and 5 mTorr total pressure. The plasma contained 50% Ar and 50% O2 for the fabrication of the single-doped NiO:Nb film (AΝ film), and N2 gas for the incorporation of N in the Ni-O-Nb structure. The N2 in plasma was introduced by keeping constant the flow rates of O2 and N2 gasses (O2/N2 = 1) and reducing the amount of Ar gas, namely 94% Ar, 3% O2, and 3% N2 (film AN1); 50% Ar, 25% O2, and 25% N2 (film AN2); and 6% Ar, 47% O2, and 47% N2 (film AN3). All films had the single phase of cubic NiO and both Nb and N in the Ni-O structure were revealed by XPS experiments. The roughness of the films was increased with the increase in N in plasma. Post-deposition thermal treatment improved the crystallinity and reduced the structural disorder of the films. The AN2 film was found to be the most transparent of all films, exhibiting the widest band gap, 3.72 eV, and the narrowest Urbach tail states' width, 313 meV. The AN and the AN2 films were employed to form NiO/TiO2 heterostructures. The NiO:Nb/TiO2 and NiO:(Nb,N)/TiO2 heterostructures exhibited a visible transmittance of around 42% and 75%, respectively, and both showed rectification properties. Upon illumination with UV light, the NiO:(Nb,N)/TiO2 diode exhibited enhanced photovoltaic performance when compared to the NiO:Nb/TiO2 solar cell: the short-circuit current densities were 0.2 mA/cm2 versus 1.4 μA/cm2 and the open-circuit voltages were 0.5 V versus 0.2 V. The output characteristics of the p-NiO:(Nb,N)/n-TiO2 UV photovoltaics can be further improved by proper engineering of the individual layers and device processing procedures. [ABSTRACT FROM AUTHOR]

Permanent Magnet Synchronous Machine (PMSM) is widely utilised in numerous industrial applications due to its precise control capabilities. However, these motors frequently encounter operational faults, potentially leading to severe safety and performance issues. Consequently, effective health monitoring techniques for early fault detection are essential to maintain optimal performance and extend the lifespan of these systems. This study presents a qualification‐based methodology for diagnosing faults in three‐phase PMSMs through vibration–current data fusion analysis. The stator faults, specifically inter‐turn short circuits (ITSC) induced via bypassing resistances, were investigated using experimental data from a custom‐built test rig. The collected current and vibration signals were transformed into statistical features. Various operating scenarios were diagnosed utilising a deep regulated neural network (RegNet), an improved convolutional neural network based on an enhanced residual architecture. The proposed approach was assessed through various metrics including training efficiency, precision, recall, f1‐score, and accuracy, and compared against several neural network methods. The findings reveal that the proposed RegNet model achieves perfect accuracy, attaining 100%. This research highlights the efficacy of data fusion analysis and deep learning in fault diagnosis, facilitating proactive maintenance strategies and improving the reliability of PMSMs in diverse industrial applications and renewable energy systems. [ABSTRACT FROM AUTHOR]

The present study addresses the issue of varying fault locations within a distribution system, which leads to fluctuations in short-circuit currents and requires the implementation of adaptive protection strategies for network reliability. This paper presents a novel adaptive protection scheme that specifically considers these fault location variations using directional overcurrent relays (DOCRs). Unlike previous research on adaptive protection, which does not adequately account for fault location variations, this method employs deep neural networks (DNNs) for online fault location detection. In the verification process, the effectiveness of the proposed methodologies was assessed by analyzing the time derivative of a trained machine learning model for fault identification. This approach enables the immediate detection of fault locations within the distribution system and facilitates the transmission of the setting group index to activate preset optimal coordination parameter values for the system relays. Crucially, the proposed method ensures that the coordination constraints remain intact across various adaptive settings, relying on precise fault identification through machine learning. The practical significance of this approach lies in its applicability to real-world systems because the proposed solutions and protective settings can be easily implemented using commercially available relays. To evaluate its effectiveness, the adaptive protection scheme was tested on three distribution networks: IEEE 14-Bus, 15-Bus and 30-Bus. The comparative test results highlight that the proposed method significantly improves the speed of the protection system for distribution networks when compared to existing studies, making it a valuable contribution to enhancing network reliability and performance. [ABSTRACT FROM AUTHOR]

In modern power systems, reliable electricity supply is crucial. This study analyzes the impact of small hydro power plants (SHPP) and photovoltaic (PV) systems on a low-voltage network using DigSILENT PowerFactory software tool. Results show that PV systems increase total harmonic distortion (THD), while sHPP reduces THD and significantly increases short-circuit currents during faults. These findings highlight the importance of strategic integration of distributed generation (DG) sources to maintain network quality and stability. [ABSTRACT FROM AUTHOR]

Aiming to study the electrical characteristics of photovoltaic cells during the flight of solar-powered unmanned aerial vehicles, this work combines a photovoltaic cell equivalent circuit model and a thermodynamic model. The influence of wing surface temperature and its influencing factor-solar radiation is of primary concern. A solar radiation model is established to explore the impact of solar irradiance on temperature and photovoltaic cell output. Atmospheric temperature and four basic parameters of photovoltaic cell, including open-circuit voltage, short-circuit current, voltage, and current at maximum power point under standard conditions are treated as input parameters. The surface temperature, the variation of output voltage, current, and power are studied with the altitude changing from 0 to 35 km and time from 0 to 24 h in spring equinoxes. Results find that with the increase in altitude, the surface temperature of the photovoltaic cell decreases first and then increases. The voltage of the photovoltaic cell decreases as the temperature increases, and the voltage-time curve varies at altitudes below 25 km and above 30 km. The peak power is available at an altitude between 15 and 20 km. The above findings can be applied to study energy generations and flows of solar-powered vehicles. [ABSTRACT FROM AUTHOR]

As power generation systems with increasingly higher capacities are interconnected with distribution networks, a pressing need arises for a thorough analysis of their integration and the subsequent impacts on medium-voltage lines. This study conducts a comprehensive evaluation, encompassing both steady-state and transient behaviours, leading to a holistic assessment of a real-world biogas generation system integrated into a medium-voltage network. Although the methodology does not introduce revolutionary concepts, its detailed application on a real feeder under various operating conditions adds practical value to the existing body of knowledge. The methodology explores various aspects, including voltage profiles, load capacity, power losses, short-circuit currents, and protection coordination in steady-state conditions. Additionally, a transient analysis is performed to examine the system's response under fault conditions. This systematic approach provides a deep understanding of the system's behaviour across diverse operational scenarios, enriching the field with practical insights. The key contributions of this study include identifying the effects of distributed generation systems (DGSs) on short-circuit currents, protection coordination, and defining voltage levels that briefly exceed the CBEMA quality curve. The benefits of incorporating a generation system into a distribution network are discussed from various technical perspectives. In a peak demand scenario, with a 1.72 MW generation capacity, the phase current experiences a notable reduction of 35.78%. Concurrently, the minimum peak demand voltage increases from 12.62 to 12.83 kV compared to a nominal voltage of 12.7 kV. Furthermore, the contribution of the generation system to the short-circuit current remains minimal, staying below 4% even under the most adverse conditions. However, our findings reveal that voltage levels exceed the upper limit of the CBEMA quality curve briefly during a single-phase fault with generation, which could potentially damage electronic equipment connected to the grid. Nonetheless, the likelihood of encountering a single-phase grounding fault with zero resistance remains low. [ABSTRACT FROM AUTHOR]

This paper puts forward a selection principle and an optimization configuration method for short-circuit current-limiting measures to address the increasingly severe short-circuit current-exceeding problem brought about by the high-speed development of large power grids. Firstly, we introduce the function principle and the advantages and disadvantages of various short-circuit current-limiting measures in the power system and give the selection conditions of generalized short-circuit current-limiting measures. Then, we adopt the hierarchical analysis method (AHP) and entropy weighting method (EWM) to evaluate the weights of the indicators of the short-circuit current level, the line-loading level, the active loss, and the economic cost; perform the selection of multiple short-circuit current-limiting schemes after the combination of the assigned weights; and describe the generalized process of engineering used to solve the problem of short-circuit currents exceeding limits. We then provide a generalized process with which to solve the short-circuit current-exceeding problem in engineering. Finally, we take the actual large-scale power grid as an example, propose multiple short-circuit current-limiting schemes for a 220 kV power grid, and carry out the selection of optimal schemes to verify the validity and reliability of the study. The results show that this process plays an important role in controlling the short-circuit current of the power system, maintaining the safe and stable operation of the power system and improving the power system's grid structure. [ABSTRACT FROM AUTHOR]

One SMEG can generate a maximum V oc and I sc of 0.57 V and 66 μA when a small amount of LiCl is dropped on one side at ambient humidity. V oc and I sc reach up to 3.55V and 204 μA when six SMEGs are connected in series or in parallel. The series connection of six SMEGs successfully lit an LED and a calculator, respectively. [Display omitted] In response to the energy crisis caused by the exhaustion of fossil energy sources, as well as to combat global warming and achieve carbon neutrality, a sandwiched-structure fabric-based moisture-enabled electricity generator (SMEG) has been developed. Cotton fabric coated with MWCNT and PEDOT: PSS solution is used as the upper and bottom electrodes, while the acid-treated cotton fabric with coating PVA and HCl hydrogel electrolyte serves as the middle layer. A single SMEG can generate a maximum open-circuit voltage (V oc) of 0.44 V and a maximum short-circuit current (I sc) of 30 μA. When a drop of LiCl is dripped on one side of SMEGs, the maximum V oc and I sc increases to 0.57 V and 66 μA, respectively. The decline in output performance slows down when LiCl is applied. The V oc increases almost linearly in series and reaches 3.55 V when six SMEGs are connected, while the I sc increases linearly in parallel and reaches 204 μA when six SMEGs are connected. The maximum power density of a single SMEG yields 0.29 μW/cm2 with an external resistance of 1 kΩ. The series connection of six SMEGs successfully lit an LED and a calculator under ambient humidity conditions, demonstrating their potential application in small electronics. [ABSTRACT FROM AUTHOR]

With the large-scale integration of renewable energy into the grid, traditional short-circuit current (SCC) calculation methods for synchronous generators are no longer applicable to inverter-based non-synchronous machine sources (N-SMSs). Current SCC calculation methods for N-SMSs often use a single-machine multiplication method, which tends to overlook the internal variability of N-SMSs within power plants, leading to low calculation accuracy. To address this issue, this paper first derives an analytical expression for SCC in grid-connected inverters under low voltage ride through (LVRT) control strategies. Then, a single-machine steady-state SCC calculation model is proposed. Based on the classification of N-SMSs, a practical SCC calculation model for renewable power plants is introduced, balancing accuracy and computational speed. The feasibility of the model is validated through simulations. The proposed method enables simple calculations to obtain the steady-state voltage and SCC at the machine terminal, offering strong engineering practicality. [ABSTRACT FROM AUTHOR]

Background: Newly approved highly effective modulation therapies (HEMT) have been life-changing for people with CF. Although these drugs have resulted in significant improvements in lung function and exacerbation rate, bacterial populations in the lung have not been eradicated. The mechanisms behind the continued colonization are not completely clear. Methods: We used a humanized rat to assess the effects of ivacaftor therapy on infection outcomes. Rats harbor an insert expressing humanized CFTR cDNA, including the G551D mutation. hG551D rats were treated with ivacaftor either during or before infection with P. aeruginosa. The response to infection was assessed by bacterial burden in the lung and mucus burden in the lung. Results: We found that hG551D rats treated with ivacaftor had reduced bacteria present in the lung in the acute phase of the infection but were not different than vehicle control in the chronic phase of the infection. Similarly, the percentage of neutrophils in the airways were reduced at the acute, but not chronic, timepoints. Overall weight data indicated that the hG551D rats had significantly better weight recovery during the course of infection when treated with ivacaftor. Potentiation of the G551D mutation with ivacaftor resultant in short-circuit current measurements equal to WT, even during the chronic phase of the infection. Despite the persistent infection, hG551D rats treated with ivacaftor had fewer airways with mucus plugs during the chronic infection. Conclusions: The data indicate that the hG551D rats have better outcomes during infection when treated with ivacaftor compared to the vehicle group. Rats have increased weight gain, increased CFTR protein function, and decreased mucus accumulation, despite the persistence of infection and inflammation. These data suggest that ivacaftor improves tolerance of infection, rather than eradication, in this rat model. [ABSTRACT FROM AUTHOR]

Two-step photon upconversion solar cells (TPU-SCs) based on III–V semiconductors can achieve enhanced sub-bandgap photon absorption because of intraband transitions at the heterointerface. From a technological aspect, the question arose whether similar intraband transitions can be realized by using perovskite/III–V semiconductor heterointerfaces. In this article, we demonstrate a TPU-SC based on a CsPbBr3/GaAs heterointerface. Such a solar cell can ideally achieve an energy conversion efficiency of 48.5% under 1-sun illumination. This is 2.1% higher than the theoretical efficiency of an Al0.3Ga0.7As/GaAs-based TPU-SC. Experimental results of the CsPbBr3/GaAs-based TPU-SC show that both the short-circuit current JSC and the open-circuit voltage VOC increase with additional illumination of sub-bandgap photons. We analyze the excitation power dependence of JSC for different excitation conditions to discuss the mechanisms behind the enhancement. In addition, the observed voltage-boost clarifies that the JSC enhancement is caused by an adiabatic optical process at the CsPbBr3/GaAs heterointerface, where sub-bandgap photons efficiently pump the electrons accumulated at the heterointerface to the conduction band of CsPbBr3. Besides the exceptional optoelectronic properties of CsPbBr3 and GaAs, the availability of a CsPbBr3/GaAs heterointerface for two-step photon upconversion paves the way for the development of high-efficiency perovskite/III–V semiconductor-based single-junction solar cells. [ABSTRACT FROM AUTHOR]

This manuscript presents a comprehensive evaluation of Cs3Sb2I9 (Eg = 1.95 eV) as a potential absorber for indoor photovoltaic (IPV) applications. Using computational modeling, we developed a baseline model of the device structure (FTO/TiO2/Cs3Sb2I9/PolyTPD(poly(N,N'-bis-4-butylphenyl-N,N'-bisphenyl)benzidine)/Au), which experimentally achieved a power conversion efficiency (PCE) of 3.7% under white light-emitting diode (WLED) illumination at 3.2 W m−2 (1000 lx). By increasing the source transmission power density from 3.2 W m−2 (6%) to 53.31 W m−2 (100%), we significantly enhanced the device's performance. Key parameters such as absorber layer thickness and defect density, along with parameters of the electron transport layer (ETL) and hole transport layer (HTL), were optimized, such as doping concentration, electron affinity (χ), and bandgap (Eg), were optimized. Our simulations demonstrated that the optimized device can achieve a remarkable PCE of 38.77%, with an open-circuit voltage (VOC) of 1.47 V, a short-circuit current density (JSC) of 1.55 mA cm−2, and an excellent fill factor (FF) of 89.09%. Additionally, we proposed a new device architecture, AZO/TNT/Cs3Sb2I9/SrCu2O2/Ni, capable of delivering 38.77% PCE under WLED illumination. This study highlights the critical role of computational modeling in optimizing device design, offering a cost-effective and efficient alternative to experimental methods. [ABSTRACT FROM AUTHOR]

Hybrid bilayer nano-heterojunction (NiPcTs) thin films, with a p-type active donor layer and n-type silicon (Si) acceptor, were manufactured at substrate temperatures of 300 K and 400 K. Using a thermal evaporation technique under vacuum conditions of 10−5 mbar and a deposition rate of 12 nm/min, these films were deposited onto two aluminum (Al) electrodes to construct the hydride bilayer photovoltaic solar cell (PVSC). The electrical characteristics of the Al/NiPcTs/Si/Al hybrid nano-heterojunction thin layer were investigated. The findings demonstrated an open-circuit voltage (Vm) of 0.25 V, a short-circuit current density (Im) of 2.77 mA/cm2 and a fill factor (FF) of 0.391. Under illumination with a halogen lamp at an intensity of 55 mW/cm2, the conversion efficiency (η) was 5.03% at a substrate temperature of 400 K. Theoretical calculations indicated that the optical energy gap of the NiPcTs thin layers depends on the annealing temperature. The optical band gap narrows as the annealing temperature rises but then widens as the temperature increases to 400 K. Comparing theoretical and experimental calculations of the electronic and electrical properties showed that the best model for solar cell applications was achieved. [ABSTRACT FROM AUTHOR]

Background and Aim: Several approaches have been employed to mitigate methane emissions from livestock, with varied results. This study evaluated the effects of shade-dried ground garlic leaf (GL) powder and papaya leaf (PL) powder as crop waste on feed intake, growth performance, ruminal microbial counts, gut epithelial barrier functions, and meat quality in goats. Materials and Methods: Forty male adult Beetal goats were randomly divided into five treatment groups: (1) Control (basal diet only); (2) basal diet supplemented with 6% bromodichloromethane (BCM); (3) basal diet supplemented with 30% GL powder; (4) basal diet supplemented with 26% PL powder; and (5) basal diet supplemented with 30% GL powder and 26% PL powder (GP). Results: Average weight gain, feed conversion ratio, fecal score, and albumin improved in the GP. Aspartate transferase increased significantly in BCM, GL, and PL and was insignificant in the GP group compared with the C group. There was a 13% decrease in methanogen count in PL compared with C, but this difference was not significant between BCM and GP. Ruminal bacteria and protozoa were lowest in GL. Ruminal papilla height and surface area increased in the supplemented groups compared with C (p < 0.05). In vitro experiments using isolated ruminal epithelia revealed a 39% increase in short-circuit current in GP compared with C (p < 0.05). For meat parameters, the pH 24 h decreased significantly in GL compared to BCM. Conclusion: Dietary supplementations with GL and PL alone or in combination improved growth parameters and gut performance and reduced rumen methanogen levels without altering meat quality parameters. Proper diet formulation and further research on other ruminants may help reduce greenhouse gas emissions from livestock. [ABSTRACT FROM AUTHOR]

We present an experimental study of the effects of driving current direction on ferromagnetic resonance in Ni36Fe64 foils. The radio-frequency (rf) driving current was applied to Ni36Fe64 foils of different shapes. In rectangular samples with a close-to-uniform flow of the applied current along the long edge of the sample, we find the resonance field to follow a simple "cos" dependence on the angle between the current and external dc magnetic field. We argue that this behavior cannot be explained by the in-plane demagnetizing field of the rectangular foil. In triangular samples, where the current partially flows along all three sample edges, we observed three independent "cos" features. The latter suggests individual contributions from different areas with different current directions. We were able to switch off one of these contributions by covering one edge of the triangular sample with a conducting overlayer and thereby effectively short-circuiting the corresponding current path. Our findings highlight the significance of driving current distributions in ferromagnetic resonance experiments. [ABSTRACT FROM AUTHOR]

The long half-life and the high decay energy of beta sources play a critical role in improving the performance of betavoltaic micro-nuclear batteries. In this study, the pure beta source 14C in the form of powder, which can be transformed into an ultra-thin film by using (14C6H5NH)2CO, was selected to design planar 4H-SiC p–n junction betavoltaic batteries. A comprehensive model was developed utilizing the Monte Carlo code and the COMSOL Multiphysics code to predict the output performance. As a result, based on a 100 μm-thick (14C6H5NH)2CO source with a maximum power density of 1.86 μW/cm2 and the current fabrication technology of 4H-SiC p–n junction, we optimized the thicknesses of the p−-type region (4.2 µm) with a doping concentration of Na = 3 × 1016 cm−3 and the n−-type region (5.8 µm) with a doping concentration of Nd = 2 × 1014 cm−3. The corresponding predicted performance values included the short-circuit current density of 0.1 μA/cm2, the open-circuit voltage of 2.15 V, and the maximum power density of 0.2 μW/cm2. Moreover, the energy conversion efficiency of the semiconductor converter can reach 10.6%, while the overall battery efficiency was determined to be 2.9%. Therefore, this research provides a feasible structure for a planar 4H-SiC p–n junction energy converter utilizing the (14C6H5NH)2CO source and presents a powerful model for predicting the performance of planar betavoltaic batteries. [ABSTRACT FROM AUTHOR]

The correct generator circuit breaker (GCB) dimensioning is essential for the safe and reliable operation of a power plant or generation system. The dimensioning is usually based on standardized calculation methods according to standards (IEC standard 60909‐0, IEC/IEEE standard 62271‐37‐013, IEEE Std C37), often supplemented by selected transient calculations. A non‐systematic approach can often be observed here, which does not adequately take into account significant influencing variables or operating states of the generator. This article therefore systematically examines various parameters that influence the short‐circuit current components of the generator and are relevant for the dimensioning of the generator circuit‐breaker: short‐circuit angle, operating point, impedance ratios, phase clearing, switching arc, and fault arc. The results of the current parameters most relevant to the dimensioning of the GCB were then compared for different calculation methods. Special attention was paid to the effect of the switching and fault arc, which were modelled as a constant arc voltage, and its effect on the short‐circuit currents is systematically recorded. This work aims to summarize all relevant variables that influence the generator short‐circuit current and are relevant for the dimensioning of the GCB and to present the different results based on a short‐circuit calculation according to the standard and transient calculation to create a basis for a proper dimensioning of the generator circuit breaker. [ABSTRACT FROM AUTHOR]

This article presents the results of research on the thermal state of vacuum switch contacts during the conduction of short-circuit currents. This state is directly related to the value of the flowing current and the operating conditions of the switch. These conditions are mildest in the case of the conduction of operating currents through closed contacts. The situation worsens significantly when short-circuit currents are conducted, and the greatest destructive effects occur during commutation processes. Exceeding a certain level of contact destruction usually leads to the loss of the switching capacity of the switch. In vacuum switches, tracking the thermal state of the contacts is particularly difficult due to the inaccessibility of transducers or measurement sensors inside the chamber. In such a case, simulation studies verified by experimental results are important. This paper presents the results of such studies, directed at their practical implementation in the design and operation of vacuum switches. Simulation studies were conducted to analyze the thermal processes occurring in the contacts of vacuum switches during the conduction of short-circuit currents. Special attention was paid to the influence of contact parameters on the thermal processes occurring during the conduction of short-circuit currents. In addition to simulations, experimental studies were carried out to verify the simulation results. Ultimately, the research results presented are intended to provide practical knowledge of the design and operation of vacuum switches, particularly with regard to the contact heating processes during the conduction of short-circuit currents. [ABSTRACT FROM AUTHOR]

The performance of composite-based triboelectric nanogenerators (C–TENGs) was significantly enhanced through laser surface patterning and graphite coating. The laser etching process produced accurate and consistent patterns, increasing surface area and improving charge accumulation. SEM imagery confirmed the structural differences and enhanced surface properties of the laser-etched C–TENGs. Graphite fibers further augmented the contact surface area, enhancing charge accumulation and diffusion. Experimental results demonstrated that the optimized C–TENGs, especially those with line patterns and graphite coating, achieved a maximal 98.87 V open-circuit voltage (VOC) and a 0.10 µA/cm2 short-circuit current density (JSC) under a 20 N external force. Environmental tests revealed a slight decrease in performance with increased humidity, while long-term stability tests indicated consistent performance over three weeks. Practical application tests showed the potential of C–TENGs integrated into wearable devices, generating sufficient energy for low-power applications, thereby highlighting the promise of these devices for sustainable energy solutions. [ABSTRACT FROM AUTHOR]

This study examined the potential application of metallic coatings to mitigate the adverse effects of ultraviolet (UV) and infrared (IR) light on photovoltaic modules. Titanium coatings were applied on low-iron glass surfaces using magnetron sputtering at powers of 1000, 1250, 1500, 1750, 2000, and 2500 W. The module with uncoated glass served as a reference. The Ti layer thickness varied from 7 nm to 20 nm. Transmittance and reflectance spectra were used to calculate visible light transmittance Lt, UV light transmittance Ltuv, solar transmittance g, and visible light reflectance Lr. The obtained parameters indicated that the thinnest Ti layer (1000 W) coating did not significantly affect light transmittance, but thicker layers did, altering the Lt, g, and Lr factors. However, every sample noticeably changed Ltuv, probably due to the natural formation of a UV-reflective thin TiO2 layer. The differences in fill factor (FF) were minimal, but thicker coatings resulted in lower open-circuit voltages (Uoc) and short-circuit currents (Isc), leading to a reduction in power conversion efficiency (PCE). Notably, a Ti coating deposited at 2500 W reduced the power of the photovoltaic module by 78% compared to the uncoated sample but may protect modules against the unwanted effects of overheating. [ABSTRACT FROM AUTHOR]

This study investigates a carbon-based all-perovskite tandem solar cell (AP-TSC) with the structure ITO, SnO₂, Cs₀.₂FA₀.₈Pb(I₀.₇Br₀.₃)₃, WS₂, MoO₃, ITO, C₆₀, MAPb₀.₅Sn₀.₅I₃, PEDOT: PSS, Carbon. The bandgap configuration of the cell is 1.75 eV/1.17 eV, which is theoretically limited to 36% efficiency. The effectiveness of embedding cubic plasmonic metallic nanoparticles (NPs) made of Gold (Au) and Silver (Ag) within the absorber layers to eliminate the requirement for thicker absorber layers, decrease manufacturing costs and Pb toxicity is demonstrated in our analysis. This analysis was conducted using 3D Finite Element Method (FEM) simulations for both optical and electrical calculations. Prior to delving into the primary investigation of the tandem structure, a validation simulation was conducted to demonstrate the accuracy and reliability of the simulations. Notably, the efficiency mismatch observed during the validation simulation, specifically in relation to the incorporation of metallic nanoparticles (NPs), amounted to a mere 0.01%. To mitigate the potential issues of direct contact between metallic NPs and perovskite materials, such as increased thermal and chemical instability and recombination at the NP surface, a 5 nm dielectric shell was applied to the NPs. The incorporation of cubic core-shell Ag NPs resulted in a 15.32% enhancement in short-circuit current density, from 16.39 mA/cm² to 18.90 mA/cm², and a 15.68% increase in overall efficiency, from 26.9 to 31.12%. This research paves the way for the integration of core-shell metallic NPs in AP-TSCs, highlighting a significant potential for efficiency and stability improvements. In a dedicated section the band alignment of the sub-cell was addressed. Additionally, a thermal investigation of the proposed tandem structure was conducted, demonstrating the robustness of the proposed AP-TSC. Finally, the sensitivity analyses related to input parameters and the challenges associated with large-scale fabrication of the proposed AP-TSC were extensively discussed. [ABSTRACT FROM AUTHOR]

Non-radiative recombination of perovskite solar cells (PSCs) will increase as a result of the numerous crystallographic defects that the solution-grown perovskite films will cause, particularly at the grain boundary and film surface. As a result, it negatively influences the performance of the device. Consequently, lowering perovskite film defects is a useful strategy for raising the efficiency of PSCs. This study reports a grain regeneration and passivation approach that can decrease the recombination loss of the perovskite layer/charge transfer layer interface and the grain border. Guanidine iodide (GAI) treatment of perovskite films is the means by which this objective is accomplished. Unlike most methods that use GAI to post-treatment the perovskite layer or add GAI into the perovskite precursor solution, this work uses GAI for pre-treatment before spin coating the perovskite layer. It can effectively passivate surface defects and increase the grain size of perovskite films by controlling the crystallization process. The water stability of devices was enhanced, the short-circuit current (Jsc), filling factor (FF), and power conversion efficiency (PCE) of PSCs were markedly improved, and non-radiative recombination was successfully reduced. The best efficiency of PSCs was 20.56% after the additional GAI treatment was applied to the perovskite layer, an 11.9% increase over the efficiency of the control device without GAI treatment. This method has the advantage of being simple and straightforward, providing a feasible pathway for the low-cost preparation and commercialization of PSCs. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerators (TENGs) made from biocompatible materials serve as promising integrated power sources for portable wearable electronics due to many advantages such as lightweight, high flexibility, simple technique, and excellent breathability. In this work, we report the fabrication of electrospun polycaprolactone micro-nanofiber films (s-PCL) and convex-microdome-patterned polydimethylsiloxane (c-PDMS) utilizing electrospinning and micromolding techniques. These materials, s-PCL and c-PDMS, are utilized as positively and negatively charged tribosurfaces, respectively, in the development of a bioTENG device. The developed TENG device can generate a superior power output of 2 mW with an open-circuit voltage (VOC) of 188 V and short-circuit current (ISC) of 18.5 µA, even under a low triggering frequency of 5 Hz. In addition, TENG possesses outstanding durability and output performance stability over a continuous operation of nearly 16,000 cycles. Furthermore, the TENG demonstrates its capacity to harvest mechanical energy and convert it into electricity, capable of directly illuminating more than 100 LEDs. The electrospun s-PCL- and c-PDMS-based TENG can be considered for self-powdered wearable devices attached to fingers, wrists, feet, and other human body parts. [ABSTRACT FROM AUTHOR]

Dye-sensitized solar cells (DSSCs) exhibit considerable potential as a promising technology, particularly when addressing the challenge of replacing the costly Platinum (Pt) counter electrode (CE) with economically viable and chemically stable CE materials. This study examines the use of two-dimensional hexagonal-shaped nickel oxide nanosheets substituted with varying mol% of lithium (1, 3, and 5 %) (Li (1–5%)-NiO NSs) as the counter electrodes (CEs) for DSSCs. The facile hydrothermal method was employed for the preparation of NiO and Li (1–5 mol%)-NiO samples. The BET analysis of NiO and Li (1–5%)-NiO indicates that higher concentrations of Li1+ ions in Ni2+ ions sites lead to an increase in the overall surface area of NiO. This leads to an elevated number of exposed electrocatalytic active sites which resulted in enhancing the rate of reduction of I 3 − ions. The cyclic voltammetry (CV) result of 5 mol% of Li substituted NiO (5-LNO) shows outstanding electrocatalytic activity towards the redox reaction of I 3 − / I − redox mediator among the as-prepared CEs. The DSSCs assembled with 5-LNO CE show an excellent power conversion efficiency (η) of 5.84 % with short-circuit current (J s c) of 18.76 mAcm−2, and open-circuit voltage (V o c) of 0.80 V which is higher than Pt-based CE (η of 4.05 % with J s c of 10.16 mAcm−2, and V o c of 0.69 V). The DSSCs fabricated with 5-LNO CE exhibit excellent photovoltaic performance because of their high active surface area and enhanced electrical conductivity. The 5-LNO CE has low cost, significant electrocatalytic activity, less toxicity, and superior device efficiency than NiO, other Li (1–3%)-NiO, and Pt CEs, making it a suitable candidate for Pt-free DSSCs application. [ABSTRACT FROM AUTHOR]

The performance of dye-sensitized solar cells (DSSC) primarily depends upon many factors, such as the thickness of the semiconductor layer at the working electrode, dye/sensitizer concentration, and electrolyte. A methodical study is required in one place to deliberate the impact of all these factors on DSSC performance for better understanding and further advancement of the technology. This work emphasizes optimizing the absorption layer, specifically investigating the relationship between the thickness of the TiO2 layer and the concentration of N719 dye. The objective is to elucidate the interconnected effects of these parameters on the overall performance of the device. Additionally, the optimization of electrolyte composition was done with varying concentrations of additives, such as iodine, 4-tert-butyl-pyridine (TBP), guanidinium thiocyanate (GuNCS), and 1-butyl-3-methylimidazolium iodide (BMII) of electrolyte. Initially, the devices with varying TiO2 absorption layers were fabricated. The efficiency, fill factor (FF), open-circuit voltage (VOC), and short-circuit current (ISC) of devices were studied. The drop in open-circuit voltage (VOC) was noticed with the increase in thickness of the TiO2 layer. The highest efficiency was observed at 7.17% with the device fabricated using 6 absorption layer (17.46 μm) of TiO2, 0.7 mM concentration of N719 dye, and 0.03-M iodine, 0.1-M GuNCS, 0.5-M TBP, and 0.6-M BMII in electrolyte. Future developments in this research could focus on further fine-tuning these parameters for improved efficiency and exploring additional innovations in DSSC technology, ultimately contributing to the advancement of sustainable and efficient solar energy conversion systems. [ABSTRACT FROM AUTHOR]

On a sunny day, the front side of the bifacial solar cells is illuminated with direct and the rear side with the diffused light. Therefore, it is important to study the effect of diffusion and direct light on the bifacial solar cell. In this study, the effects of diffuse and direct light and temperature on the textured bifacial solar cell were determined by simulation. According to the obtained results, the optimal value of the angle of base of texture for a bifacial silicon solar cell is 580. On a cloudy day, under diffuse light illumination on both sides, the planar and optimally textured solar cells have an efficiency of 13.14% and 16.03% and a short-circuit current of 4.34 mA/cm² and 5.49 mA/cm². The short-circuit current is 2.28 mA/cm² and 2.88 mA/cm2 when only front side is illuminated with diffuse light. On a sunny day, when direct light falls on the front side and diffuse light falls on the rear side, the short-circuit current of the planar and optimally textured solar cell are 27.79 mA/cm² and 35.16 mA/cm², respectively. Short-circuit current are 25.73 mA/cm2 and 32.65 mA/cm² when only front side illuminated with direct light. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract The correct generator circuit breaker (GCB) dimensioning is essential for the safe and reliable operation of a power plant or generation system. The dimensioning is usually based on standardized calculation methods according to standards (IEC standard 60909‐0, IEC/IEEE standard 62271‐37‐013, IEEE Std C37), often supplemented by selected transient calculations. A non‐systematic approach can often be observed here, which does not adequately take into account significant influencing variables or operating states of the generator. This article therefore systematically examines various parameters that influence the short‐circuit current components of the generator and are relevant for the dimensioning of the generator circuit‐breaker: short‐circuit angle, operating point, impedance ratios, phase clearing, switching arc, and fault arc. The results of the current parameters most relevant to the dimensioning of the GCB were then compared for different calculation methods. Special attention was paid to the effect of the switching and fault arc, which were modelled as a constant arc voltage, and its effect on the short‐circuit currents is systematically recorded. This work aims to summarize all relevant variables that influence the generator short‐circuit current and are relevant for the dimensioning of the GCB and to present the different results based on a short‐circuit calculation according to the standard and transient calculation to create a basis for a proper dimensioning of the generator circuit breaker.

Photoluminescence imaging under sunlight excitation has in the recent years been proposed as a promising inspection technique of field-installed photovoltaic modules. Virtually, all studies have been conducted in full sunlight and clear sky conditions. A study in which photoluminescence images had been acquired at an irradiance level below 100 W m−2 using the lock-in technique has shown the potential of these images with respect to defect analysis. Additionally, as on-site measurement techniques are subject to weather conditions, it would be favorable to extend the applicability of photoluminescence imaging to a wider range of irradiance levels. A method for photoluminescence imaging which does not use the lock-in technique for the purpose of filtering of sunlight was proposed recently. The present study extends the application of this approach to diffuse irradiance conditions. We demonstrate that the method gives valuable information about the modules also in the case of image acquisition under diffuse global in-plane irradiance as low as 40 W m−2. Photoluminescence images acquired under low irradiance are comparable to electroluminescence images acquired at 10% of short-circuit current. Photoluminescence imaging has also been conducted successfully from the rear of bifacial modules in these illumination conditions. [ABSTRACT FROM AUTHOR]

The fabrication of quantum well solar cells with surface photonic crystal (SPC) and embedded photonic crystal (EPC) structures has resulted in solar cells with improved properties. When compared to reference solar cells (RSCs), the photoluminescence (PL) intensities of SPC solar cells and EPC solar cells have been enhanced by 89% and 114%, respectively. This indicates improved light absorption and emission characteristics in the presence of the periodic patterns (PCs). The short-circuit current (Isc) of EPC solar cells is 31% higher than that of RSCs, suggesting improved light absorption and carrier generation. On the other hand, SPC solar cells exhibit a 6% higher Isc compared to RSCs, and the open-circuit voltage has increased simultaneously. The fill factors (FF) of the solar cells are 84% for RSCs, 86% for SPC solar cells, and 76% for EPC solar cells. The higher FF in SPC solar cells suggests improved charge carrier collection efficiency. In terms of photoelectric conversion efficiency, SPC solar cells demonstrate a 10.6% increase, while EPC solar cells show a 7.7% increase. These improvements indicate that the incorporation of PCs in the solar cells enhances their ability to convert light into electrical energy. These findings highlight the potential of photonic crystals engineering for enhancing the performance of solar cells. [ABSTRACT FROM AUTHOR]

We studied photoinduced charge transfer (CT) states and their dissociation processes at the donor/acceptor (D/A) interface of PTB7/BTAx (x = 1 and 3) nonfullerene organic thin-film solar cells using density functional theory (DFT) and time-dependent DFT calculations. We focused on the CT distances and electron coupling in the CT state generated by photoexcitation and the Huang–Rhys (HR) factors that describe the nonadiabatic processes associated with vibronic interactions. The PTB7/BTA3 system with a large short-circuit current density (JSC) exhibited a large charge CT distance and electronic coupling. Contrastingly, the PTB7/BTA1 system with a low JSC has a large HR factor because of the low-wavenumber vibrational modes in the CT state of the D/A complex and is prone to nonadiabatic relaxation to the ground state. Systematic theoretical analysis of the excitonic states in the D/A complex has provided insight into the control of CT exciton dynamics, namely JSC and electron–hole recombination. [ABSTRACT FROM AUTHOR]

Abstract Mechanical stability is one of the core capabilities of power transformers. External short‐circuit accidents are the main cause of winding instability. International Electrotechnical Commission 60076‐5 standard recommends a method to calculate the short‐circuit strength of power transformer windings by comparing the stress within windings under the effect of the maximum electromagnetic force with the critical stress of the winding. This method assumes that the maximum deformation will be produced by the maximum electromagnetic force, which corresponds to the first peak of the waveform. However, owing to the interactions between disks during the vibration process, the maximum deformation may occur after the occurrence of the maximum electromagnetic force. The hysteresis phenomenon between disk deformation and electromagnetic force is studied. The definition of the hysteresis phenomenon during the vibration process is first demonstrated, and the mechanism of the hysteresis phenomenon is investigated. The vibration model is established. By decoupling analysis, the conditions for the formation of hysteresis are proposed, and the mechanism of the hysteresis phenomenon is validated by the experiment, which is conducted on a winding sample. In the deformation formula, the term that determines the time‐varying characteristic is found. The waveform‐determining term is the difference between the two cosine components, whose frequencies are the natural vibration frequency and the electromagnetic force frequency. When the two frequencies are close, the maximum deformation lags behind the maximum force, and the hysteresis phenomenon occurs.

This study presents a significant advancement in tandem dye-sensitized solar cells (T-DSSCs) through the strategic synthesis of novel triazatruxene (TAT) sensitizers MS-1 and MS-2. These organic sensitizers demonstrate exceptional light-harvesting capacity and overall performance, pushing the boundaries of power conversion efficiency (PCE) in DSSCs. The MS-1-based DSSCs achieved an impressive PCE of 12.81%, while MS-2 sensitizers reached a notable 10.92%. These efficiencies represent significant improvements over the conventional N719 dye (7.60%), demonstrating the potential of metal-free organic sensitizers in DSSC technology. The key to these noteworthy results lies in the molecular design of the organic sensitizers. The triazatruxene donor segment in the MS-1 and MS-2 dyes, featuring a rigid structure and efficient intramolecular charge transfer (ICT), proved to be a game-changer for photovoltaic properties. Building on these results, we explored an innovative parallel tandem cell (PT-DSSC) configuration. By connecting separate cells containing N719 and MS-1 sensitizers, we achieved a record efficiency of 12.89% with enhanced short-circuit current density (JSC) and open-circuit voltage (VOC)compared to single-dye cells. This study highlights the potential of molecular engineering in organic sensitizers and device optimization to enhance DSSC performance, paving the way for further advancements in solar cell technology. [ABSTRACT FROM AUTHOR]

Copyright of Zhejiang Electric Power is the property of Zhejiang Electric Power Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Energy harvesting from ambient sources present in the environment is essential to replace traditional energy sources. These strategies can diversify the energy sources, reduce maintenance, lower costs, and provide near-perpetual operation of the devices. In this work, a triboelectric nanogenerator (TENG) based on silane-coupled Linde type A/polydimethylsiloxane (LTA/PDMS) is developed for harsh environmental conditions. The silane-coupled LTA/PDMS-based TENG can produce a high output power density of 42.6 µW/cm2 at a load resistance of 10 MΩ and operates at an open-circuit voltage of 120 V and a short-circuit current of 15 µA under a damping frequency of 14 Hz. Furthermore, the device shows ultra-robust and stable cyclic repeatability for more than 30 k cycles. The fabricated TENG is used for the physiological monitoring and charging of commercial capacitors to drive low-power electronic devices. Hence, these results suggest that the silane-coupled LTA/PDMS approach can be used to fabricate ultra-robust TENGs for harsh environmental conditions and also provides an effective path toward wearable self-powered microelectronic devices. [ABSTRACT FROM AUTHOR]