Input Power Research Articles

Antenna Integration for Millimeter-Wave RF Sensing and Millimeter-Wave Communication Mountable on a Platform.

An array antenna for millimeter-wave communication and an array antenna for millimeter-wave sensing are designed and put together into one structure. Because millimeter-wave signals become weaker fast with the increasing distance and any kind of error in the required functions of the antenna has to be minimized, pointing error from the target direction should be prevented. The device is a millimeter-wave sensing antenna with high directivity to check the straight link between the TX and RX sides of wireless communication. A 24 GHz 8-by-16 array antenna which generates stronger signals for sensing resolves the drawback of a 28 GHz 1-by-4 array antenna that is commonly seen in 5G wireless terminals. The sensing and communication antennas are integrated as a planar structure mountable on platforms, which is investigated with regard to forming wireless links over a distance of several meters with an input power of less than 0 dBm. Additionally, in the event of a reflecting surface disturbing the straight path and worsening the pointing error in RF signal transfer, the dual-capability of the combination is presented on the basis of intuitive electromagnetic experiments.

Ratchet-mediated resetting: current, efficiency, and exact solution

We model an overdamped Brownian particle that is subject to resetting facilitated by a ratchet potential on a spatially periodic domain. This asymmetric potential switches on with a constant rate, but switches off again only upon the particle’s first passage to a resetting point at the minimum of the potential. Repeating this cycle sustains a non-equilibrium steady-state, as well as a directed steady-state current which can be harnessed to perform useful work. We derive exact analytic expressions for the probability densities of the free-diffusion and resetting phases, the associated currents for each phase, and an efficiency parameter that quantifies the return in current for given power input. These expressions allow us to fully characterise the system and obtain experimentally relevant results such as the optimal current and efficiency. Our results are corroborated by simulations, and have implications for experimentally viable finite-time resetting protocols.

Experimental Demonstration of a Solar Powered High Temperature Latent Heat Storage Prototype

The challenge of imbalances between renewable energy supply and grid demand underscores the significance of energy storage in microgrids. This research presents an empirical assessment of the operational capabilities of a full-scale Electrical Thermal Energy Storage (ETES) prototype system named Thermal Energy Storage Power On Demand (TES.POD®), in solar-abundant and harsh desert conditions. The system incorporates a high-temperature commercial-scale latent heat thermal energy storage, integrated with a Stirling engine. Over a continuous span of 10 days, from September 26th to October 6th, 2022, the input and output power, as well as the heat transfer fluid temperatures during charging and discharging were monitored to assess the power block and system efficiencies. Results from the experiments reveal that this prototype effectively maintains a near-constant electricity production rate of 10.5 ± 1 kW for a discharge duration of 13 hours. Average cycle efficiency stands at 23%, while power block efficiency reaches 25%. These findings collectively suggest the system's potential for applications involving long duration thermal energy storage.

A Study on the Efficient Degradation of Sulfur Hexafluoride by Pulsed Dielectric Barrier Discharge Synergistic Active Gas

SF6 is a strong greenhouse effect gas, which is widely used in high-voltage electrical equipment such as circuit breakers and high-voltage switchgear because of its excellent insulation performance and arc extinguishing ability. In recent years, the use and emission of SF6 have been rising, and with the proposal of the dual carbon strategic goal, its harmless degradation has become an urgent problem to be solved. In this paper, SF6 was degraded by pulsed DBD plasma technology and O2. Studies have shown that the addition of O2 can effectively promote the degradation of SF6. With the increase in the added O2 content, the DRE and EY of SF6 first increased and then decreased. Under the conditions of the input power of 50 W, SF6 concentration of 2%, and gas flow rate of 50 mL/min, the reaction system obtained the highest DRE and EY of 58.40% and 5.24 g/kWh when the O2 content was 1%, respectively. In the SF6/Ar/O2/H2O system, the addition of H2O could improve the product selectivity of SO2F2, and when the O2 concentration was 1%, the highest selectivity of SO2F2 was 48.96%, and the concentration was 8006.76 ppm. The addition of O2 inhibited the production of SO2, and with the addition of the O2 system, SO2F2 and SOF4 were the main components of degradation products; however, there were also SOF2, SO2, SiF4, SF4, etc. In this paper, the decomposition path of O2 under SF6 was analyzed in detail according to infrared spectroscopy and decomposition products.

Thermal Performance Assessment of a Novel Hybrid Reactor for Solar Thermochemical Processes

Solar thermochemical conversion processes offer a promising pathway for converting sunlight into clean, sustainable, and carbon-neutral fuels. A solar chemical reactor is one of the most essential components that utilizes concentrated solar energy to drive chemical reactions. In this study, a novel hybrid solar reactor is designed, fabricated, and tested to assess its thermal performance for the purpose of studying the solar thermochemical conversion processes in Thailand for the first time. It was performed under different heating modes regarding solar heat and/or electrical heat, with the aim to support day-and-night operation and variations in solar radiation conditions. The reactor was experimentally tested under on-sun, off-sun, and hybrid conditions using air as a heat transfer fluid. As a result, with one kWth solar thermal power input absorbed, the solar reactor achieved high temperatures exceeding 500 °C from the hybrid system while the reactor absorption efficiency was found to be 4%. The reactor demonstrated the possibility and reliability of performing solar thermochemical conversion processes under day-and-night and unstable solar radiation conditions.

Plasma performance and operational space with an RMP-ELM suppressed edge

The operational space and global performance of plasmas with edge-localized modes (ELMs) suppressed by resonant magnetic perturbations (RMPs) are surveyed by comparing AUG, DIII-D, EAST, and KSTAR stationary operating points. RMP-ELM suppression is achieved over a range of plasma currents, toroidal fields, and RMP toroidal mode numbers. Consistent operational windows in edge safety factor are found across devices, while windows in plasma shaping parameters are distinct. Accessed pedestal parameters reveal a quantitatively similar pedestal-top density limit for RMP-ELM suppression in all devices of just over 3×1019 m−3. This is surprising given the wide variance of many engineering parameters and edge collisionalities, and poses a challenge to extrapolation of the regime. Wide ranges in input power, confinement time, and stored energy are observed, with the achieved triple product found to scale like the product of current, field, and radius. Observed energy confinement scaling with engineering parameters for RMP-ELM suppressed plasmas are presented and compared with expectations from established H and L-mode scalings, including treatment of uncertainty analysis. Different scaling exponents for individual engineering parameters are found as compared to the established scalings. However, extrapolation to next-step tokamaks ITER and SPARC find overall consistency within uncertainties with the established scalings, finding no obvious performance penalty when extrapolating from the assembled multi-device RMP-ELM suppressed database. Overall this work identifies common physics for RMP-ELM suppression and highlights the need to pursue this no-ELM regime at higher magnetic field and different plasma physical size.

Impacts of operating variables in forward roll coating process of viscous hybrid nanofluid

Abstract Roll coating plays a significant role in various coating industries such as magnetic records, wallpapers, wrapping, adhesive tapes, books and magazines, photographic and plastic films. The thin layer coating of a magnetohydrodynamic (MHD) viscous hybrid nanofluid by passing through the space between two co-rotating rolls has been studied in an isothermal and incompressible analysis. The governing equation of mass and momentum are obtained then dimensionless using lubrication approximation theory (LAT). The velocity, pressure gradient, and pressure distribution are determined by the exact solution. Using Simpson’s (3/8) rule for numerical integration, the complex integral is examined. Important engineering parameters including power and roll separating force delivered by the rolls to the fluid are also estimated numerically. Raising the volume fraction of nanoparticles raises the pressure distribution and pressure gradient while having little effect on the velocity profile. It seems that the magnetic field and hybrid nanofluid, both seem very advantageous for the efficient roll coating process, controlling the separation force, power input, and distance between the attachment and separation point.

Microwave‐sintered mullite structural ceramics based on low‐grade bauxite applied for fracturing proppants

AbstractThis study aimed to assess the feasibility of manufacturing fracturing proppants by microwave sintering and using low‐grade bauxite as raw material. The effects of microwave hotspot SiC and sintering additive MnO2 content on the performance of the mullite‐based structural materials were studied, respectively. The optimum sintering condition was determined by single‐factor experiments. The sintering process and mechanism were explored based on the analysis of physicochemical properties, phase transitions, and microstructure. The results showed that (1) mullite ceramic composites could be successfully prepared only with SiC added and with poor interparticle bonding microstructure. (2) With the addition of MnO2 and CaO, the granular‐shaped mullite crystals transformed into rod‐like mullite crystals, forming a net structure. (3) As the input power increased, the overfast sintering rate would reduce proppants' mechanical properties, and it was also necessary to select a reasonable sintering time to avoid overburning. (4) When the mass ratio of MnO2:CaO:SiC:bauxite was 2:1.5:12:84.5 and under the sintering condition of 1000 W, 2 h, the performance (breakage ratio of 8.5% under 28 MPa closed pressure, apparent density of 2.58 g/cm3, turbidity of 52 FTU, and acid solubility of 6.77%) could meet the requirements of the Chinese Petroleum and Gas Industry Standard (SY/T 5108–2014). This study provides a powerful way for reducing the fracturing cost, which not only improves the low‐grade bauxite utilization scale within the ceramic industry, but also expands the application of microwave sintering technology in mullite structural materials for the petroleum and gas industry.

Artificial Neural Network Model for Estimating the Pelton Turbine Shaft Power of a Micro-Hydropower Plant under Different Operating Conditions

The optimal performance of a hydroelectric power plant depends on accurate monitoring and well-functioning sensors for data acquisition. This study proposes the use of artificial neural networks (ANNs) to estimate the Pelton turbine shaft power of a 10 kW micro-hydropower plant. In the event of a failure of the sensor measuring the torque and/or rotational speed of the Pelton turbine shaft, the synthetic turbine shaft power data generated by the ANN will allow the turbine output power to be determined. The experimental data were obtained by varying the operating conditions of the micro-hydropower plant, including the variation of the input power to the electric generator and the variation of the injector opening. These changes consequently affected the flow rate and the pressure head at the turbine inlet. The use of artificial neural networks (ANNs) was deemed appropriate due to their ability to model complex relationships between input and output variables. The ANN structure comprised five input variables, fifteen neurons in a hidden layer and an output variable estimating the Pelton turbine power. During the training phase, algorithms such as Levenberg–Marquardt (L–M), Scaled Conjugate Gradient (SCG) and Bayesian were employed. The results indicated an error of 0.39% with L–M and 7% with SCG, with the latter under high-flow and -energy consumption conditions. This study demonstrates the effectiveness of artificial neural networks (ANNs) trained with the Levenberg–Marquardt (L–M) algorithm in estimating turbine shaft power. This contributes to improved performance and decision making in the event of a torque sensor failure.

Efficacy, kinetics, inactivation mechanism and application of cold plasma in inactivating Alicyclobacillus acidoterrestris spores

As spores of Alicyclobacillus acidoterrestris can survive traditional pasteurization, this organism has been suggested as a target bacterium in the fruit juice industry. This study aimed to investigate the inactivation effect of cold plasma on A. acidoterrestris spores and the mechanism behind the inactivation. The inactivation effect was detected by the plate count method and described by kinetic models. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), the detection of dipicolinic acid (DPA) release and heat resistance detection, the detection and scavenging experiment of reactive species, and cryo-scanning electron microscopy were used to explore the mechanism of cold plasma inactivation of A. acidoterrestris. The results showed that cold plasma can effectively inactivate A. acidoterrestris spores in saline with a 3.0 ± 0.3 and 4.4 ± 0.8 log reduction in CFU/mL, for 9 and 18 min, respectively. The higher the voltage and the longer the treatment time, the stronger the overall inactivation effect. However, a lower gas flow rate may increase the probability of spore contact with reactive species, resulting in better inactivation results. The biphasic model fits the survival curves better than the Weibull model. SEM and TEM revealed that cold plasma treatment can cause varying degrees of damage to the morphology and structure of A. acidoterrestris spores, with at least 50 % sustaining severe morphological and structural damage. The DPA release and heat resistance detection showed that A. acidoterrestris spores did not germinate but died directly during the cold plasma treatment. 1O2 plays the most important role in the inactivation, while O3, H2O2 and NO3− may also be responsible for inactivation. Cold plasma treatment for 1 min reduced A. acidoterrestris spores in apple juice by 0.4 ± 0.0 log, comparable to a 12-min heat treatment at 95 °C. However, as the treatment time increased, the survival curve exhibited a significant tailing phenomenon, which was most likely caused by the various compounds in apple juice that can react with reactive species and exert a physical shielding effect on spores. Higher input power and higher gas flow rate resulted in more complete inactivation of A. acidoterrestris spores in apple juice. What's more, the high inactivation efficiency in saline indicates the cold plasma device provides a promising alternative for controlling A. acidoterrestris spores during apple washing. Overall, our study provides adequate data support and a theoretical basis for using cold plasma to inactivate A. acidoterrestris spores in the food industry.

Thermal performance analysis of a lithium-ion cell using the novel fins and the phase change material

The battery thermal management system (BTMS) plays a key role in keeping the electric vehicle battery temperature within thermal safety limits. A poorly designed BTMS may reduce the operational life of the battery. The present work aims to maintain the battery temperature below the threshold limit using the triangular and elliptical-shaped novel fins and the phase change material (PCM). Multiple arrays of these fins were fitted along the cell height in the annulus space between the cell sleeve and the casing such that the tip of the fins touches the casing. The individual and the combined performance of the fins and the PCM was assessed through temperature measurements using the thermocouples and the thermal camera at various power inputs of 30, 50 and 70 W. At 70 W, the cell operation was extended by a maximum of 250 %, 270 % and 280 % for the cell with PCM, with PCM and triangular fins and PCM with elliptical fins, respectively. The lowest extension in cell operation by 10 % was observed for the triangular fins alone at 70 W. This demonstrates the significant influence of the PCM on the cell performance. The temperature contours using the thermal camera showed that for all power settings, the peak temperature occurs at the cell center. The present studies demonstrate a significant potential for BTMS application in the combined system of elliptical fins with PCM.

Optimal design and current control strategies of an electrodynamic tape for ISS station-keeping

This study analyzes the performance of a tape-like bare electrodynamic tether as a promising propellant-free technology for the International Space Station (ISS) station-keeping, supporting the concept that the technology can provide significant mission benefits by reducing the ISS reliance on costly refueling operations for orbit maintenance. Convenient control laws for managing the electrical power supplied to the tether are proposed, exploring two distinct scenarios. The first involves using the electrodynamic tether continuously to counteract aerodynamic drag. The second adopts a cyclic approach, alternating between boosting the station with the tether and allowing for periods of natural decay. Optimal tether geometry, aimed at maximizing system efficiency, is also detailed. The study specifies an electrodynamic tether configuration featuring a 6-kilometer-long aluminum ribbon, 5 cm wide and 50 μm thick, capable of overcoming aerodynamic drag ranging from 0.40 N to 0.80 N. Additionally, numerical simulations assess the tether performance under real environmental conditions. Furthermore, the study briefly introduces the potential of a photovoltaic tether as a fully autonomous system capable of supplying the necessary input power.

The performance of CO2 reduction by dielectric barrier discharge plasma coupled Cu-Ni binary silicon-based composites

As a major greenhouse gas, the rational conversion and utilization of CO2 can help reduce carbon emissions and mitigate the greenhouse effect. In this study, mesoporous SiO2 as a carrier, with CuO and NiO employed to construct a binary metal composite silica-based catalyst, coupled with dielectric barrier discharge (DBD) plasma, for the conversion of CO2. Physicochemical analysis confirmed the successful introduction of CuO into the mesoporous SiO2. NiO and CuO bimetals were dispersed on SiO2 surfaces with large specific surface areas, ensuring an optimal distribution of metal oxide. Gas chromatography was utilized to investigate the performance of DBD-coupled x%CuO-3 %NiO/Si for CO2 conversion. The results indicated that the CuO-NiO binary composite silica catalysts significantly improved CO2 conversion, CO yield, and energy efficiency compared to the monometallic 3 %NiO/Si materials. Further microstructural analysis of the 9 %CuO-3 %NiO/Si catalyst revealed near-elliptic particles with dimensions of 200 by 500 nm and a large number of irregular fine particles attached to the surface. When the CuO loading reached an optimal level and the input power was set at 30 W, the energy efficiency of the 9 %CuO-3 %NiO/Si catalyst increased by 119.6 %. The CuO-NiO binary composite Si-based catalyst developed in this study boasts simple operation and environmental friendliness, making it highly significant for CO2 treatment.

Power over fiber using a multimode optical power with a core diameter of 50 µm

We report on the properties of the Power over Fiber (PoF) transmission link using a High-Power Laser Source operating at 976 nm and using three types of optical fiber with a core diameter of 50 µm. Two step-index profile multimode optical fibers and one fiber with a gradient index were used for optical power transmission. Optical light was converted to electricity using commercially available Photovoltaic Power Convertors (PPCs) with a maximal optical input power of 1.5 W and experimental PPCs with a maximal optical input power of 4.0 W. We experimentally proved optical power transmission up to a distance of 300 m. In the case of the commercially available working PPC and using the gradient index fiber we achieved a result of 0.534 W of electrical power and using the experimental PPC we achieved 0.645 W. In the case of the step-index optical fiber, the result was 1.3 W.

Mid-Infrared Supercontinuum Generation in Highly Nonlinear Chalcogenide Fibers

Interest in mid-infrared broadband laser light sources has surged due to applications in trace gas detection, free-space communications, and countermeasures. Progress in supercontinuum generation leverages fiber-based near-infrared and bulk-optic mid-infrared pump sources. In this paper, the Generalized Nonlinear Schrödinger Equation has been solved, using the Split Step Fourier Method, to simulate the pulse propagation and mid-infrared supercontinuum generation, inside a fiber composed of highly nonlinear As2Se3/As2S3 chalcogenide glass. The effect of various parameters, including fiber nonlinearity, Group Velocity Dispersion (GVD), input power and pulse-width, anomalous and normal dispersion pumping regime, etc. on the output supercontinuum bandwidth has been extensively studied. A tapered chalcogenide fiber is modeled to facilitate continuous simultaneous modification of the GVD and the Kerr nonlinearity parameter. Pumping the waveguides with 230-fs secant pulses at a peak power of 4.2-kW yields a mid-IR supercontinuum extending from [Formula: see text] to [Formula: see text] micrometers.

A 2.0–3.0 GHz GaN HEMT-Based High-Efficiency Rectifier Using Class-EFJ Operating Mode

In this paper, a CGH40010F GaN-based wideband RF rectifier with high rectification efficiency is presented. A novel continuous class-EFJ-mode rectifier is constructed by combining a continuous class-J-mode rectifier and class-EF-mode rectifier under specific impedance conditions. This novel continuous class-EFJ-mode rectifier has high rectification efficiency and wide bandwidth at the same time. For validation, a wideband high-efficiency class-EFJ-mode rectifier functioning within the 2.0–3.0 GHz range is designed, fabricated, and measured. The measurements indicate that, with an input power of 40 dBm and a resistance of 72 Ω on the dc load, the implemented rectifier sustains a rectification efficiency exceeding 60% across its entire operational frequency band. Meanwhile, the dimensions of the circuits are only 3 cm × 3.1 cm.

Model of non-equilibrium near-cathode plasma layers for simulation of ignition of high-pressure arcs on cold refractory cathodes

The introduction of secondary ion-electron emission into an approximate model of non-equilibrium plasma layers on hot (thermionic) cathodes of high-pressure arc discharges allows extending the model to low cathode surface temperatures. Analysis of evaluation results shows that the extended model describes glow-like discharges on cold cathodes and thermionic arc discharges on hot cathodes, as it should. In the course of glow-to-arc transitions on cold cathodes, a transient regime occurs where a hot arc spot has just formed and a significant fraction of the current still flows to the cold surface outside the spot, so that the near-cathode voltage continues to be high. The power input in the near-cathode layer is very high in this regime, and so is the electron temperature in the near-cathode region. The mean free path for collisions between the atoms and the ions in these conditions exceeds the thickness of the layer where the ion current to the cathode is generated. A new method for evaluation of the ion current under such conditions is implemented. The developed model is applicable for cathode surface temperatures below the boiling point of the cathode material and may be used for multidimensional simulations of ignition of high-current arcs on refractory cathodes.

Optimizing methane plasma pyrolysis for instant hydrogen and high-quality carbon production

The European Green Deal has set a target for Europe to achieve net-zero greenhouse gas emissions by 2050, necessitating a transition to more sustainable energy sources. Hydrogen gas (H2) has emerged as a promising solution, with methane pyrolysis presenting a viable method for its production. This study explores the optimization of methane plasma pyrolysis for hydrogen and high-quality carbon production. Employing a statistical approach by a design of experiment software, critical process parameters are systematically analyzed to predict their impact within a defined range. Additionally, the paper conducts comprehensive characterization of the solid carbon produced during pyrolysis using imaging, spectroscopic and elemental analysis, and gas sorption analysis methods. The experimental investigation was conducted using a thermal plasma reactor with several settings of influential parameters including methane gas (CH4) content in the plasma gas, electric current, and arc length. The DC-transferred plasma arc is formed using a variable gas mixture of argon gas (Ar) and CH4, with a constant flow rate of 5 Nl/min. Thirteen tests were designed, evaluating responses such as power input, process stability, and H2 yield. The H2 yield indicates the hydrogen produced from CH4, with 100% representing total conversion. While the process exhibited inconstancy, attributed to reactor design constraints, a high H2 yield of 67%–100% was achieved. The results indicate that a higher CH4 content in the plasma gas and extended arc lengths disturb the plasma arc, hence reducing the H2 yield. Increased power input, achieved through higher amperage levels, and a wider reaction zone eased by extending the arc length both led to an improved H2 yield. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) revealed microstructural differences, with carbon samples from the filter exhibiting finer textures and carbon samples from the reactor larger sizes and dendritic particles. Raman spectroscopy confirmed crystalline graphitic-like structures with low defect concentrations, a finding supported by X-ray diffraction (XRD) analysis. Inductively coupled plasma mass spectroscopy (ICP-MS) analysis confirmed high-purity carbon with slight impurities from initial filter contamination. Brunauer-Emmett-Teller (BET) specific surface area calculations based on gas sorption analysis showed significant variations, with filter-collected samples exhibiting 40–170 m2/g and reactor-collected ones showing 7–30 m2/g.

Effect of Ti3SiC2 concentration on corrosion resistance and ICR in bipolar plates composite ceramic coatings

Ti3SiC2, a MAX-phase ceramic, amalgamates metallic and ceramic traits, delivering exceptional electrical conductivity and corrosion resistance. In this research, Ti3SiC2 composite coatings were applied to 316 L stainless steel via low-power atmospheric plasma spraying (APS), aiming to bolster the electrical and corrosion resistance attributes of bipolar plates (BPPs). A power input of 15 kW notably enhanced coating density, yielding a Ti3SiC2 concentration of 19.2 wt% in the coating. Extremes in the spraying power led to either diminished deposition efficiency or a reduction of Ti3SiC2 mass fraction below 5 wt%. Tafel curves demonstrated that specimens with elevated Ti3SiC2 mass fractions exhibited robust corrosion resistance, characterized by a self-corrosion potential of −162.5 mV and a self-corrosion current density of 1.7217 × 10−6 A·cm−2. Moreover, the interfacial contact resistance (ICR) between the coating and the gas diffusion layer was remarkably low (down to 5.49 mΩ·cm−2), indicating enhanced surface electron transfer with increasing Ti3SiC2 mass fractions.

Optimal Power Model Predictive Control for Electrochemical Energy Storage Power Station

Aiming at the current power control problems of grid-side electrochemical energy storage power station in multiple scenarios, this paper proposes an optimal power model prediction control (MPC) strategy for electrochemical energy storage power station. This method is based on the power conversion system (PCS) grid-connected voltage and current to establish a power prediction model for energy storage power stations, achieving a one-step prediction of the power of the power station. The power prediction error is used as a power regulation feedback quantity to correct the reference power input. Considering the state of charge (SOC) constraint of the battery, partition the SOC into different states. Using SOC as the power regulation feedback, the power of the battery compartment can be adjusted according to the range of the battery SOC to prevent SOC from exceeding the limit value, simultaneously calculating the power loss of the energy storage power station to improve the energy efficiency. The objective function is to minimize the power deviation and power loss of the power station. By solving the objective function, the optimal switching voltage vector of the converter output is achieved to achieve optimal power control of the energy storage power station. The simulation results in various application scenarios of the energy storage power station show that the proposed control strategy enables the power of the storage station to quickly and accurately track the demand of grid scheduling, achieving the optimal power control of the electrochemical energy storage power station.