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Computational fluid dynamics uses numerical methods and algorithms to solve and analyse problems that involve fluid flows. Computers may be used to perform the calculations required to simulate the interaction of liquids and gasses with a surface defined by boundary conditions. Thermodynamics is the science of the relationship between heat, work, temperature, and energy. Computational modelling for microchannel reactor design was performed to investigate the effects of various factors on the efficiency and performance of an autothermal reforming system. The yield and productivity from the chemical process were determined by performing computational fluid dynamics and thermodynamic analysis. Strength and weakness were assessed under different reaction conditions. Design recommendations were provided and operation strategies were mapped out. The results indicated that operation at millisecond contact times is feasible, but optimisation of reaction conditions is necessary to balance efficiency and performance. The conversion to hydrogen is influenced greatly by the feed composition, which must be controlled precisely within certain needed limits to maximize the yield and productivity from the autothermal reforming process while avoiding the problems of combustion or explosion. Additionally, the efficiency difference between feed compositions is determined by thermodynamic analysis. The calculated output power of the autothermal reforming reactor is of the order of thousands of kilowatts per cubic meter.

The utilization of electric energy is rising in the technological world. Solar PV (photovoltaic) cells convert sunlight into electricity, and sunlight radiation also has heat, reducing the panel's efficiency. The heat should control the limited value or otherwise reduce the panel's performance so that heat is moved to the cooling medium, thus maintaining the heat within the functioning limit. The proposed method is explained by the probability of cooling the monocrystalline and polycrystalline structures used as neem oil through an integrated oil container fitted into the unit's backside—the neem oil acts as phase-changing material (PCM). The solar PV rear side neem oil absorbs the heat of the solar PV panel. The neem oil is not filled in the backside tank completely for the reason that the oil needed some breathing gap. The breathing gap of PCM is to enhance the heat-withstand efficiency. The backside neem oil is replaced every 30 min. As an outcome, the front side of solar PV heat is reduced. Neem oil has not polluted the environment and is thus also used to exchange noxious mineral oils. The neem oil moved from the depository tank to the backside of the unit and together into an additional depositor tank, thus being able to be reused. The proposed method is investigated, and functioning comparison occurs in different PV types, such as monocrystalline and polycrystalline modules, with various kinds of edible oil. Thus, the critical outcomes of the monocrystalline and polycrystalline PV panels are to decrease the panel temperature by 2.29% and 4.34%, respectively, and enhance the efficiency of the PV panels by 15.0% and 17.8%, respectively. [ABSTRACT FROM AUTHOR]

This paper presents the novel design and analysis of a 25 W broadband Class-AB GaN HEMT-based power amplifier working over 0.9–1.7 GHz. A large signal model of the Wolfspeed-make GaN HEMT CG2H40025 has been used in this design. The comprehensive design process has been carried out with the help of the Advanced Design System software by Keysight. Instead of conjugately matching the load and source impedance obtained from load-pull analysis of a nonlinear model of CG2H40025, the value of load and source impedance has been tuned with the help of a novel design approach of an ideal matching design approach. Thus, to achieve an output power of more than 25 W and a flat large signal gain of 15.425 ± 0.375 dB, a novel design approach has been employed to create input and output matching networks, maintaining a lower Q value results in broad bandwidth and for determining the load and source impedances. The circuit has been fabricated on Roger's substrate RO4350B having a dielectric constant of 3.66 and a loss tangent of 0.0031. The unique design approach based on electromagnetic simulation of the circuit at each design step yielded experimental results that agreed very well with the simulated results. The fabricated power amplifier achieves a power-added efficiency of over 54.78% and a drain efficiency of over 55.45% throughout the entire frequency range. It also delivers a maximum output power of 32.18 W at 1.3 GHz. This power amplifier is developed for L-band Foliage Penetrating Radar. [ABSTRACT FROM AUTHOR]

In practical applications, the proton exchange membrane (PEM) fuel cell stack is often exposed to wind environment, and the speed and direction of the ambient wind are random. The performance variation of an open-cathode PEM fuel cell under various ambient wind directions and speeds was studied. The results show that when the ambient wind direction is opposite to the cathode reactant or from the side of stack, the stack temperature increases and the stack power decreases finally. Moreover, with the increase in the wind speed, the running time of the stack is shortened significantly. For the ambient wind in the same direction as the cathode gas, the stack power increases at a high current and decreases at a low current. For the given speed and direction of ambient wind, the increased air flow rate of fan could alleviate the interference of ambient wind on the stack performance and temperature. However, while the stack temperature is more than the allowable maximum operating temperature, the stack power declines even though the air flow rate of fan increases. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology 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.)

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.)

The efficient recovery of the waste heat from the industrial sector can represent an essential step in global energy saving, with the proper usage of other on-grid power resources available for specific high-energy consumers. A simple, low–cost energy conversion system was tested here to recover a part of the waste heat dissipated by a gasoline engine's exhaust pipe under the car's stationary testing mode at temperatures around 80 – 100 oC. The main components of this system were a copper–made thermal collector, a commercial thermoelectric energy generator (TEG) module TEC1 – 12706 and a pin-fin heat sink under natural air convection cooling. Under the open-circuit test, heat transfer rates between 4.54 W and 5.56 W were evacuated by the heat sink. A DC electronic load RL was connected at the TEG outputs, and voltage values between 0.566 V and 1.242 V were recorded for output power values between 0.03 W and 0.16 W when RL was modified from 1 Ω to 10 Ω.

Various factors, such as solar radiation, the tilt angle of solar photovoltaic modules, and the conversion efficiency of these modules, play crucial roles in influencing the power output of photovoltaic (PV) systems. When it comes to predicting faults in distributed photovoltaic power sources, the primary focus and challenges revolve around the constraints imposed by maximum power. Consequently, a fault prediction method was introduced to distributed photovoltaic power sources, centered on the calculation of maximum admissible power. The methodology involved constructing an output model for distributed photovoltaic power sources to ascertain the limits of reactive power. By calculating the distribution of harmonic currents based on the maximum admissible power, the short-circuit capacity was determined. Faults in distributed photovoltaic power sources and categorized them into different fault warning levels. Through experimental analysis, it is demonstrated that the proposed method predicts photovoltaic power loss data more accurately, thus facilitating effective fault detection. Furthermore, the method computes the correlation of warning indicators for each node in the distributed photovoltaic power source, thereby establishing the warning fault status for each node. In the experiments, three nodes are in the green warning state, six in the yellow warning state, two in the orange warning state, and one in the red warning state, underscoring the favorable fault warning effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Compared to the traditional wet-mate underwater power supply method, Magnetic Coupling Resonant Wireless Power Transfer (MCR-WPT) technology boasts advantages such as excellent insulation, high safety, and convenient operation, showing promising application prospects in the field of power supply for underwater vehicles and other mobile underwater devices. In order to explore the transmission characteristics of this technology underwater, this article first establishes a traditional mathematical model, and then modifies the underwater model through analysis of changes in coil self-inductance and mutual inductance, as well as the impact of eddy current losses. Using the modified mathematical model of the underwater MCR-WPT system, the transmission characteristics are analyzed, and simulations and experimental validations are performed using MATLAB R2022a software. In the study of frequency characteristics, it is found that the system operates optimally when both ends of the circuit work at the resonant state; that is, when finput = fresonance = 100 kHz, the output performance is at its best, and the optimal resonant frequency significantly improves power and transmission efficiency. When the input frequency is less than 87.3 kHz or greater than 122.9 kHz, the output power decreases to less than half of the maximum power. In the investigation of load effects, the optimal load for maximizing system output power was identified, but the load that maximizes transmission efficiency is different from this optimal load. This study provides strong theoretical support and guidance for improving the performance of underwater wireless power transmission systems. [ABSTRACT FROM AUTHOR]

This study presents a novel solar updraft tower power plant (SUTPP) system, which has been designed to achieve the simultaneous utilization of solar and wind energy resources in desert regions, in response to the pressing demand for sustainable and efficient renewable energy solutions. The aim of this research was to develop an integrated system that is capable of harnessing and converting these abundant energy sources into electrical power, thereby enhancing the renewable energy portfolio in arid environments. The methodology of this study involved the design and construction of a prototype SUTPP, comprising a 53 m high tower, a 6170 m2 collector, five horizontal-axis wind turbines, and a thermal energy storage layer made up of pebbles and sand. The experimental setup was meticulously detailed, and experiments were conducted to collect data on the system's performance under various environmental conditions. Subsequently, three-dimensional numerical simulations were performed to explore the effects of ambient wind speed and solar radiation on the output power of the SUTPP. The results indicate that the output power of the system increases with the increase in ambient wind speed and solar radiation. The impact of solar irradiation on output power was observed to diminish as ambient wind speeds increased. Notably, as the inlet wind speed rose from 4 m/s to 12 m/s, the output power showed a substantial increase of 727%. The numerical simulations revealed that ambient wind speed has a more pronounced effect on power output compared to solar radiation. Furthermore, it was found that the influence of solar radiation is significant at low wind speeds, with its impact decreasing as wind speed increases. This research provides essential guidance for the design and engineering of highly efficient solar thermal energy utilization projects, representing a significant advancement in the field of renewable energy technology deployment in desert environments. [ABSTRACT FROM AUTHOR]

Water evaporation-driven power generation has attracted wide attention in recent years due to its capability to obtain electricity from the natural water evaporation. However, low output power and difficulties in large-scale manufacturing are still changeable for further development. Here, we design an asymmetric electrode with the three-layer structure (carbon cloth/filter paper/copper plate) for an evaporation-driven generator. Mesoporous NiCo2O4 nanoparticles are loaded on the net-like structured carbon cloth to provide more ion exchange microchannels, which can promote water evaporation. As a result, the generator can output electricity at room temperature with a stable open circuit voltage of 200 mV for about 24 h. The output current density and the output power of the generator can reach 90 μA/cm2 and 14 μW/cm2, respectively. This research provides an effective strategy for sustainable energy harvesting based on the water evaporation device without the limitation of dimension. [ABSTRACT FROM AUTHOR]

The description of a passive W-band multiplier and its calculation, development process and methodology for measuring its characteristics are given. A parametric multiplier based on nonlinear resistance is implemented, which uses a pair of Schottky barrier diodes with Pt/Ir contacts. The operating principle of the proposed frequency multiplier is described. The electromagnetic modeling data and the experimental results on the efficiency and the conversion and return losses are presented. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Mine Automation is the property of Industry & Mine Automation Editorial Department 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.)

Combined Heat and Power (CHP) systems have attracted substantial interest in the past decades as they offer higher thermal efficiency than single power generation systems. Various parameters affect the performance of a cogeneration system, including environmental and operating conditions of gas turbine and Heat Recovery Steam Generator (HRSG) system. In this study, the effects of 15 substantial parameters on the performance of a CHP system are investigated using Thermoflow software. The most influential parameters are identified by performing a comprehensive parametric study and sensitivity analysis. The results indicate that only 3 parameters, including the percentage of gas turbine load, ambient temperature, and ambient pressure, affect the gross output power, i.e., increasing ambient temperature from -20 to 50 oC leads to an 8% increase in efficiency of the CHP system. In contrast, moving from the highest elevation in Iran to a beach can result in a 20% reduction in the output power of the cogeneration system. This is while 8 parameters significantly affect the efficiency of the cogeneration system. For instance, changing gas turbine load from 100% to 25% leads to a 25% reduction in the efficiency of the cogeneration system. Furthermore, the correlations between important input and output parameters are presented, which can be easily used for different environmental and working conditions of cogeneration systems and are, in fact, a roadmap for the feasibility of using this type of system in various regions and working conditions. [ABSTRACT FROM AUTHOR]

Output power is an important performance metric related to static or quasi-static wireless power transfer (WPT). As an important component of WPT, the electrical parameters of a magnetic coupling mechanism (MCM) are directly related to its output characteristics. Notably, an optimal WPT design is largely based on MCMs using the same primary and secondary coils. However, in some scenarios involving limited space, the physical structure and electrical parameters of the coils cannot be kept completely consistent. Based on the influence of physical parameters on coupling performance and system characteristics, an optimal design method for MCMs using different primary and secondary coils to ensure maximum output power is proposed. The best receiving coil within a limited space that achieves maximum power at a specific location was selected. Experiments were conducted, with the corresponding results verifying the correctness of theoretical and simulation analyses, as well as the effectiveness of the proposed method.

Brushless Direct Current (BLDC) motors have seen significant improvements across various electrical applications. The growing focus on motor design research highlights the BLDC motor's superior efficiency compared to traditional motors, which consume more power. BLDC motors are compact, lightweight, energy-efficient, and easy to control, making them ideal for modern applications. This study aims to enhance BLDC motor design and performance by employing the Taguchi method, Response Surface Methodology (RSM), and Finite Element Method (FEM) for multi-stage optimization. A 26-watt BLDC electric fan motor is the reference model for this study. The Taguchi method helps identify optimization points, guiding further enhancements in the second stage. The study proposes a design with improved output power, torque, and efficiency. The final design achieves a 15% higher energy efficiency than the reference model, with a 10 W increase in output power and a 0.032 Nm increase in maximum torque. The FEM analysis using JMAG software v 21.2 validates the proposed design, which shows improved configurations compared to the reference model, demonstrating the efficiency of the optimization techniques for BLDC motor design. [ABSTRACT FROM AUTHOR]

Though CO2 power cycles are preferred for diesel engine waste heat recovery, a very high operating pressure of the CO2 power cycle is an issue of concern. To address this issue, in the present study, CO2-propane and CO2-R152a mixtures with various CO2 mass fractions are proposed as the working fluid of a regenerative transcritical power cycle recovering waste heat of a diesel power plant. To reduce the possibility of accidental fire hazard; the minimum permissible CO2 mass fraction is restricted to 0.3. It is observed that reducing CO2 mass fraction ensures higher output power and lesser levelized electricity cost (LEC), specifically at a lower turbine inlet pressure. Between two considered CO2-based mixture pairs, the transcritical cycle exhibits a superior performance with CO2-R152a-based mixtures. The LEC of the presented CO2-propane-based optimized cycle is about 6.36% lower compared to that of the optimized supercritical CO2 power cycle. For the CO2-R152a mixture-based cycle, the corresponding achievable reduction in LEC is about 15.20%. Turbine inlet pressures corresponding to the minimum LECs of the optimized CO2-propane and CO2-R152a mixture-based cycles are, respectively, close to 33% and 39% lower than that of the optimized supercritical CO2 power cycle. As R152a is less flammable than propane, an R152a-based mixture working fluid also ensures a safer operation compared to a propane-based mixture. [ABSTRACT FROM AUTHOR]

Solar energy has been considered as one of the leading renewable energy sources for electric power generation. Therefore, intending to deal with a low energy conversion efficiency of photovoltaic (PV) materials problems, artificial intelligence (AI) techniques are playing an essential role in enhancing the performance and reliability of photovoltaic systems. Consequently, many researchers have focused their studies on using AI applied to photovoltaic solar energy. Adaptative neural fuzzy inference system (ANFIS) has shown excellent performance and potential use among AI methods. Therefore, ANFIS architecture has been widely applied in PV systems, and many papers were found. However, a survey with classifications or comparisons was not detected. In this regard, this paper surveys the literature about ANFIS architecture applied to photovoltaic systems. And, to help the readers, the authors propose new categorization based on applicability. The six different categorizations are Solar irradiance forecasting; Photovoltaic output power estimation; Parameter identification for photovoltaic system sizing; Maximum power point tracking (MPPT); Inverter control; and Fault diagnosis photovoltaic systems. Furthermore, in each categorization, a comparison is made among the papers approached. Finally, a comparison among ANFIS architecture and other techniques also are presented in each categorization. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Chongqing University of Technology (Natural Science) is the property of Chongqing University of Technology 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.)

When it comes to the radio frequency (RF) frontend, power amplifier (PA) is one of the most important functional blocks for dependable wireless transmission. In order to provide the necessary output power, PAs boost and amplify the incoming signal, to ensure that the transmitter's signal reaches the receiver at the necessary distance. The PAs have not yet managed to find place within the transceiver circuit due to its bulky nature. Although rigorous efforts have been made to improve the linearity and efficiency of the PAs, it has come at the cost of increase in chip area. This paper focusses on design of an RFPA in an 18nm FinFET advanced node technology that is adaptable to the Sub-6 GHz frequency band of 5G communication standard so as to provide maximum output power at the operating frequency of 3.5GHz. The single stage PA, thus designed and simulated on Cadence Virtuoso provides a gain of 27.71 dB at a supply voltage of 1V. The bandwidth is 208 MHz, power gain is 25dB and the output power is 6.335 dBm. The simple design with a single transistor paves way for a considerable decrease in the chip area, thus making it possible to be placed within the transceiver chip. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerators (TENGs) present a great potential approach for low‐frequency blue energy harvesting due to their unique advantages, however, omnidirectional wave energy harvesting remains challenging in complex marine environments. Herein, an omnidirectional multi‐track spherical structure TENG (OMS‐TENG) based on eight‐track fan type TENG (FTENG) is developed for harvesting low‐frequency ocean energy. The diameter and number of PTFE balls are optimized theoretically for boosting individual FTENG output and verified experimentally. The connection mode between different tracks and layers of OMS‐TENG is further investigated for efficient omnidirectional ocean energy harvesting. The motion parameters including translation and oscillation on electrical output performances of OMS‐TENG are systematically investigated and optimized. OMS‐TENG has proved to be an efficient device for harvesting omnidirectional wave energy with excellent stability and durability in complex marine environments. The maximum instantaneous power of 1270 µW can be obtained by individual OMS‐TENG. This work provides an effective approach toward omnidirectional ocean energy harvesting and important guidance for designing sustainable energy harvester. [ABSTRACT FROM AUTHOR]

This paper designs and validates a composite functional metasurface that combines microwave absorption and vibrational energy harvesting. The metasurface is composed of an indium tin oxide (ITO) electrically conductive glass pattern layer, arrays of 1‐ethyl‐3‐methylimidazolium dicyanamide [EMIM][N(CN)2] droplets, and an underlying indium tin oxide (ITO) electrically conductive glass layer. The composite functional metasurface possesses broadband absorption performance when the microwave frequency bands are between 7.34 and 22.63 GHz, which can transform vibration energy into electrical energy simultaneously. The relationship between output power, the number of droplets, internal resistance, and the matching load of the composite functional metasurface is deeply studied. It is found that the internal resistance decreases with the increase in the number of droplet arrays. The effective output power reaches up to 125nW when there are 48 droplet arrays. This technology has promising applications in the field of intelligent and portable electromagnetic devices. [ABSTRACT FROM AUTHOR]

The stratospheric airship is a type of aerostat that uses solar energy as its power source and can fly continuously for months or even years in near space. The rapid and accurate prediction of the output power of its solar array is the key to maintaining energy balance and extending flight time. This paper establishes an online learning model for predicting the output power of the solar array of stratospheric airships. The readings of radiometers arranged on the surface of the airship are used as features for training the model. The parameters of the model can be updated in real-time during the flight process without retraining the entire model. The effect of radiometer placement on the model accuracy was also analyzed. The results show that for the continuous flight of 40 days, the online learning model can achieve an accuracy of 88% after training with 10 days of flight data and the accuracy basically reaches its highest level after 20 days. In addition, placing the radiometers at the four corners of the array can achieve a higher prediction accuracy of 95%. The online model can also accurately identify and reflect the effect of module efficiency attenuation or damage and maintain high accuracy. [ABSTRACT FROM AUTHOR]

Solar photovoltaic (PV) panels play a crucial role in sustainable energy generation, yet their power output often faces uncertainties due to dynamic weather conditions. In this study, a comparative machine learning approach is introduced, utilizing multivariate regression (MR), support vector machine regression (SVMR), and Gaussian regression (GR) techniques for precise solar PV panel power prediction. The investigation into the impact of environmental factors—solar radiation, ambient temperature, and relative humidity—on PV panel output reveals the superior predictive capabilities of SVMR models. With a mean squared error (MSE) of 0.038, a mean absolute error (MAE) of 0.17, and an R2 value of 0.99, SVMR outperforms GR and MR models. Conversely, Gaussian regression demonstrates comparatively weaker performance, yielding an R2 of 0.88, an MSE of 0.49, and an MAE of 0.63.This research underscores the reliability and enhanced accuracy of the proposed SVMR model in forecasting solar PV panel output. The outcomes presented herein carry significant implications for promoting the widespread adoption of PV panels in electricity generation, particularly in challenging environmental conditions. The findings offer valuable insights into optimizing solar PV deployment, ultimately contributing to the expansion of solar power generation in the national energy landscape. Moreover, the comparative analysis provides insights into how anticipated PV power generation can adapt to varying weather conditions, encompassing factors such as temperature, humidity, and solar radiation.

The current national standard GB/T 3836.1-2021 Explosive atmospheres-Part 1: Equipment-General requirements and the international standard IEC 60079-0:2017 Explosive atmospheres-Part 0: Equipment-General requirements stipulate that the threshold power of a radio transmitter is the product of the effective output power of the radio transmitter and the antenna gain. Under the condition of a certain threshold for the safe transmission power of radio wave explosion-proof, the larger the antenna gain, the smaller the effective output power of the radio transmitter. This will limit the improvement of wireless transmission distance by increasing the antenna gain. Therefore, it is necessary to study the correctness of the threshold power specified in the national standard GB/T 3836.1-2021 and the international standard IEC 60079-0:2017, and propose reasonable explosion-proof requirements and detection methods for radio wave transmission power. It has been proposed that the safe transmission power of radio waves is independent of antenna gain, and the threshold power of radio transmitters specified in the national standard GB/T 3836.1-2021 and the international standard IEC 60079-0:2017 is incorrect. It is proposed that the threshold for the safe transmission power of underground wireless radio waves in coal mines should be greater than 16 W and independent of antenna gain. The national standard GB/T 3836.1-2021 and the international standard IEC 60079-0:2017 stipulate that the threshold power shall not exceed 6 W, which is incorrect. A method for detecting the explosion-proof safety performance of wireless radio waves has been proposed. The method detects the output power of wireless transmitters. This not only ensures the explosion-proof safety of the detected wireless equipment, but also simplifies the detection method. The method improves the wireless radio wave transmission power of the wireless equipment, removes the limitation on antenna gain, and greatly improves the wireless transmission distance of wireless explosion-proof equipment in coal mines.

The data presented in this experiment, three model convection-shaped pipe materials were designed as an effective cooling alternative for thermoelectric power generation by designing and experimentally modeling the thermoelectric power generator system, which controls the heat transfer of hot side thermoelectric at temperatures of 150 °C, 200 °C, and 250 °C by supplying power through (alternating current: A.C.) transformers to heater coil plate. The cold side fitted to finned heat exchanger is used in combination with an air-cooling system. The purpose of obtaining electrical energy, the experiment, when comparing the three datasets into, showed that the pattern from the use of cylinder pipe materials is the design that provides the highest output power at 15.3W and maximum efficiency of 5.86% at a temperature difference of 186 °C compared to the use of square pipe materials and triangular prism pipe materials with 1.12% and 2.98% lower efficiency, respectively. The temperature control on the hot side is equally constant. The choice of convection cylinder pipe material for cooling fin heat exchanger provides the highest efficiency for thermoelectric power generation.

Inductive Wireless Power Transfer (IWPT) using magnetic induction has seen remarkable progress over the past few decades. Despite their growing popularity, IWPT systems suffer from output power instability due to variations in system parameters. This paper provides a comprehensive review of the strategies for maintaining stable output power under system parameters that deviate from the original design specifications. First, the root cause of power instability and the state-of-the-art techniques for avoiding the output power decrease are carefully examined. In addition, by comparing these methods, this paper clarifies their respective application scenarios and offers insights into their practical benefits. Furthermore, this paper outlines potential future advancements in improving the robustness and reliability of IWPT systems. As presented, the output power instability is induced by frequency mismatch and coupling coefficient variation. Resonant frequency regulation, operation frequency regulation, and coupling optimization are targeted techniques for the issues. Based on the comparison, respective application scenarios are clarified. Moreover, the trade-offs should be carefully weighed in terms of their impact, complexity, and cost. Future research directions on variable devices, closed-loop control, and new mechanisms for power stability enhancement are highlighted, thereby facilitating the pervasive application of IWPT systems.

Vertical extrinsic photoconductive semiconductor switches (PCSSs) are presented with initial characteristics comparison between V-doped 4H-SiC and Fe-doped GaN PCSS under axial triggering such as dark resistance, photoconductivity, power output, and breakdown behavior. Experiments are carried out under the 532-nm-wavelength laser with mJ-level energy and a pulse width of 30 ns. Photoconductive experiments show that the photoelectric conversion efficiency of GaN PCSS is 2.27 times higher than 4H-SiC PCSS with the same electric field strength under different laser energies from 1 mJ to 5 mJ. 4H-SiC PCSS with a dark-state resistance of $10^{12} \Omega \cdot $ cm can withstand a bias voltage of 8 kV (16 kV/mm) and laser energy of 8 mJ and the maximum output power is up to 428.7 kW, while that of GaN can only stand a bias voltage of 1 kV (2.9 kV/mm) because of low dark resistance and defect. Obvious cracks of 4H-SiC PCSS can be observed from the breakdown image after breakdown occurs, while the dark-state resistance of GaN PCSS drops from $10^{6} \Omega \cdot $ cm to $10^{4} \Omega \cdot $ cm under high DC voltage.

This paper presents high performance hydrogen-terminated diamond MOSFETs fabricated on a (111)-oriented single-crystal diamond substrate. The diamond surface was passivated by a high-quality Al2O3 grown by ALD at 350°C as well as a secondary passivation layer Si3N4 deposited by PECVD. After passivation, a low ohmic contact resistance $R_{c}$ of $0.5 \Omega \cdot $ mm was obtained and the 2DHG sheet density was as high as $1.0\times 10\,\,^{\mathrm{ 13}}\,\,{\mathrm{ cm}}^{-2}$ with a corresponding mobility of $104 {\mathrm{ cm}}^{2} /\text{V}\cdot \text{s}$ . The fabricated diamond MOSFET with gate length of $0.5 ~\mu \text{m}$ showcased a high current density of 750 mA/mm, a low on-resistance of $24 \Omega \cdot $ mm, and a high off-state breakdown voltage of 117 V. Thanks to the high current density and low on-resistance, a record high output power density of 2.1 W/mm was achieved at 10 GHz with drain biased at a low voltage of −30 V. These results demonstrate that the output current and output power can be improved by using a (111)-oriented diamond, which is benefit for high-frequency and high-power RF devices.

Abstract Accurate prediction of photovoltaic power generation is a critical technical problem for utilizing solar energy. Aiming at the problem that the model parameters are difficult to obtain in applying photovoltaic power prediction methods, this paper has used long‐term monitoring data of output power, various meteorological data, and solar irradiation intensity of photovoltaic modules. This paper establishes the functional relationship between the output power of photovoltaic modules and the irradiation intensity through Pearson correlation analysis. By deducing the distribution relationship of irradiation intensity, the prediction model of irradiation intensity based on peak sunshine hours and sunshine duration is constructed and based on 340 sites across the country 64 years peak sunshine hours and sunshine duration query database. In this work, the theoretical value of the prediction model on sunny days is close to the measured value (R2 = 0.918–0.985). The solar radiation intensity on rainy days is weak, and the prediction accuracy is low (R2 = 0.838–0.930). The relative errors between the sunshine duration and the peak sunshine hours in the database are less than 4.55% and 4.79%, respectively, under sunny conditions in each quarter, indicating that the accuracy of the database meets the actual needs.

A large part of incident solar radiation on photovoltaic (PV) modules is converted into heat, leading to overheating and reduction of PV modules performance. The present work investigates the impact of rectangular aluminium fins (RAFs) and evaporative cooling represented by cotton wicks immersed water (CWWs) on the performance and thermal behaviour of the PV module. Results indicate that the evaporative cooling attained better cooling potential than RAFs, in which the PV module temperature was reduced by 22.3%, and the output power was enhanced by 73% thanks to continuous cooling of the PV module. A slight improvement in the PV module performance was observed with RAFs due to the increased heat transfer area, which reduced temperature by up to 6.7% and increased the output power of the PV module by up to 21.3 %. Exergy analysis shows a gradual increment of the electrical exergy and exergy efficiency using CWWs, which reduces the entropy generation of it more than RAFs. The study concluded that PV modules without cooling in hot climate areas may deteriorate their performance significantly.

The substantial portion areas are customarily habituated across the world is electricity. In need of electricity generation, no equipment, instruments, motor, or any machinery is functioning. The paper portrays consequently footsteps energy carries on exploited and it draws upon non-conventional sources of energy resources. There are many types of electricity generation i.e., solar power, wind conversion system, thermal, hydro-electricity, nuclear energy. Renewable energy and Non-Renewable Energy Sources are inherent notions in the Electricity generation system. The Walking Footsteps are and untapped natural resources. While employing the Walking Footsteps energy its more concise amount of cost means that it’s modest and innocuous for human. The metamorphosis technology is intermingled that electrical energy can proselytize to mechanical energy using footsteps walking of human beings. The consequent equipment’s efficacious used for procedure of footsteps is as supervening like pipe arrangement, nozzle type, unidirectional valve, water reservoir, turbine motor of any type, and DC motor. The occupied conformance is accomplished be pertinent pressure which is strive on the water reservoir; water flows amidst the direction of nozzle into the turbine and generates electrical energy. This type of electrical energy is kept stored in the energy battery storage. There is very much load disturbance in the consumers terminal so that there will be causing global warming and load shedding. This paper defines having advantages of the global warming and load shedding in best way of cleaner the cost-effective way. [ABSTRACT FROM AUTHOR]

Enhancing the output power of stratospheric airship photovoltaic arrays during months with weak irradiance is crucial for extending the endurance of airships. Models for predicting the output power of photovoltaic arrays and the phenomenon of mismatch losses have been proposed. However, static reconstruction schemes to reduce or eliminate mismatch losses have not been studied. In this paper, an output power model for stratospheric airship arrays including the solar radiation and irradiance distribution is established. The characteristics of the irradiance distribution for the photovoltaic array (PV) are investigated through simulation. Furthermore, an innovative reverse combination configuration is developed and compared to the SP and TCT configurations in terms of performance, mismatch loss and fill factor. Finally, simulations are conducted for a full-day irradiance period of 4 days in a real wind field. The simulation results demonstrate that the proposed RC configuration significantly reduces mismatch losses and output power fluctuations, thereby enhancing the PV array's output power. This research provides interesting insights for the design of PV array topologies for stratospheric airships. [ABSTRACT FROM AUTHOR]

Energy generation systems based on FC (fuel cell) are viewed as a viable substitute for those that simply rely on thermodynamic cycles in the power production field. In this paper, a 10-stack SOFC systems performance and optimization of that utilizing a newly improved optimizer known as the Fractional-order Kho-Kho optimization method will be presented in this paper. The multi-objective optimization approach is applied in the optimization phase to achieve the desired performance goals for the SOFC system. With the help of this technique, the desired system can be optimized in accordance with two objective functions: first, the electric power of the system can be maximized, while the equalized price of the electricity produced is minimized. Then, the electrical efficiency of the system can be maximized, while the equalized price of the electricity produced is minimized. The results show that, by reducing the coefficient and increasing efficiency, optimal solutions were achieved with higher electricity prices. It is observed that an increase in energy prices led to a 9% increase in productivity, whereas a 15% increase resulted in only a 2% increase. The findings demonstrate that multi-objective optimization may be used as a sophisticated analytical tool as well as a guiding element for decision-makers utilizing such a system. [ABSTRACT FROM AUTHOR]

Adjusting the operating parameters to optimize the performance of the scroll expander has been a hot research topic among scholars. This paper innovatively combines the response surface method and NSGA2 algorithm for parameter optimization. This novel method can accurately predict the optimal operating parameters of the scroll expander and improve the overall efficiency of the scroll expander. Initially, a three-dimensional transient simulation model of the scroll expander was established, and the effects of three key operating parameters (suction pressure, exhaust pressure, and rotational speed) on the output power and isentropic efficiency of the scroll expander were analyzed through numerical simulation. On this basis, the response surface model between the input parameters and the objective function was established by using the response surface methodology. Consequently, three different optimization algorithms were compared, and it was found that NSGA-II had a better performance both in terms of convergence and solution performance,. Threfore, the NSGA-II algorithm was used for the multi-objective optimization. Under the premise of considering the maximum output power and isentropic efficiency, based on the established response surface model, the Pareto optimal solution was used to determine the optimal combination of its operating parameters: suction pressure of 1.62 MPa, exhaust pressure of 0.45 MPa, and rotational speed of 2,099.58 rpm.Finally, the numerical model is verified by the laboratory-built test bed of the Organic Rankine cycle low-temperature waste heat oilfree power generation system. The experimental results match well with the numerical simulation results and verify the model accuracy. The results from this pioneering and thorough thr study will provide a solid benchmark for the development and refinement of upcoming scroll machines. [ABSTRACT FROM AUTHOR]

We report the results of a comparison of metal–dielectric mirror coatings for mid-IR quantum-cascade lasers (QCLs). Samples of QCLs with Al2O3/Ti/Au and SiO2/Ti/Au optical coatings are fabricated and their characteristics are studied. It is shown that the use of metal–dielectric mirror coatings allows the output optical power of devices to be increased up to 93% and their threshold currents to be reduced by 1.25 times. [ABSTRACT FROM AUTHOR]

Dielectric mirrors for mid-IR quantum cascade lasers are calculated. Optimal dielectric materials are selected to minimize the absorption of laser radiation. Samples of quantum cascade lasers emitting in the spectral range of 4–5 μm and having various dielectric highly reflective mirror coatings are manufactured and their characteristics are studied. It is shown that the deposition of a highly reflective Si–Si3N4 coating on the back face of the laser cavity leads to an increase in the output optical power of the lasers by 71% compared to control samples without coatings. The use of a Si–SiO2 coating makes it possible to increase the output power of the lasers by 88%. [ABSTRACT FROM AUTHOR]

Background: Thermal ablation of solid tumors in situ can activate the immune system and produce a specific immune response against the tumor. Microwave ablation (MWA) with different parameters can ablate tumors with similar sizes and cause different local inflammatory effects. Our aim was to determine the immunological effects induced by different energy modes of MWA for a primary tumor. Methods: Seventy rabbits with VX2 tumors that were implanted subcutaneously underneath the right second nipple were treated with high-power MWA (40 W for 1 min), low-power MWA (20 W for 2 min), or surgical resection or were left without treatment (control). Survival time was evaluated by log-rank test. On day 14 after ablation, immunohistochemistry and flow cytometry were used to evaluate the T-cell immune responses. In addition, the cytokine patterns were identified by enzyme-linked immunosorbent assay. Results: Tumor eradication was achieved completely in the MWA groups, as proven by nicotinamide adenine dinucleotide diaphorase staining. Compared with the three treatment groups, the control group had a significantly higher number of pulmonary metastases and worse survival; however, no significant difference was observed among the three treatment groups. More intra-tumoral and systemic CD4+ and CD8+ T-cells were induced in the MWA groups than in the control group. Compared with operation, MWA induced more systemic CD4+ T-cells. More intra-tumoral CD4+ and CD8+ T-cells and systemic CD4+ T-cells were induced by high-power MWA than by low-power MWA. Moreover, MWA increased the interleukin 2 (IL2) and IL12 levels and decreased the IL4, IL6, and IL10 levels. Importantly, the serum IL12 level was significantly higher after high-power MWA than after low-power MWA. Conclusion: High-power MWA enhanced the type 1 T helper immune response and may be selected for the treatment of solid tumors. Future studies are needed to confirm our results [ABSTRACT FROM AUTHOR]

Accurate prediction of photovoltaic power generation is a critical technical problem for utilizing solar energy. Aiming at the problem that the model parameters are difficult to obtain in applying photovoltaic power prediction methods, this paper has used long‐term monitoring data of output power, various meteorological data, and solar irradiation intensity of photovoltaic modules. This paper establishes the functional relationship between the output power of photovoltaic modules and the irradiation intensity through Pearson correlation analysis. By deducing the distribution relationship of irradiation intensity, the prediction model of irradiation intensity based on peak sunshine hours and sunshine duration is constructed and based on 340 sites across the country 64 years peak sunshine hours and sunshine duration query database. In this work, the theoretical value of the prediction model on sunny days is close to the measured value (R2 = 0.918–0.985). The solar radiation intensity on rainy days is weak, and the prediction accuracy is low (R2 = 0.838–0.930). The relative errors between the sunshine duration and the peak sunshine hours in the database are less than 4.55% and 4.79%, respectively, under sunny conditions in each quarter, indicating that the accuracy of the database meets the actual needs. [ABSTRACT FROM AUTHOR]

The floating platform motion of an offshore wind turbine system can exacerbate output power fluctuations and increase fatigue loads. This paper proposes a new scheme based on a fast second-order sliding mode (SOSM) control and an adaptive super-twisting extended state observer to suppress the platform motion and power fluctuation. Firstly, an affine nonlinear model of the floating wind turbine pitch system is constructed. Then, a fast SOSM pitch control law is adopted to adjust the blade pitch angle, and a new adaptive super-twisting extended state observer is constructed to achieve total disturbance observation. Finally, simulations are conducted under two cases of wind and wave conditions based on FAST (fatigue, aerodynamics, structures, and turbulence) and MATLAB/Simulink. Compared with the traditional proportional integral (PI) control scheme and standard super-twisting control scheme, the platform roll under the proposed scheme is reduced by 13% and 4%, and pitch is reduced by 16% and 3% in Case 1. Correspondingly, the roll is reduced by 9% and 15%, and pitch is reduced by 7% and 1% in Case 2. For the tower top pitch and yaw moment, load reductions of 7% and 3% or more are achievable compared with those under the PI control scheme. It is indicated that the proposed scheme is more effective in suppressing floating platform motion, stabilizing output power of the wind turbine system, and reducing tower loads. [ABSTRACT FROM AUTHOR]

The objective of the paper is to amend some information provided in a previously published article “Case Studies in Thermal Engineering 55 (2024), 104139”, especially on the applicability conditions of the cost and area factor (FCAE) and the calculations of the area (APVE) and FCAE values for a photovoltaic module (PV) using both single and double mirrors. Hence, corrections are given.

For bridges with high automobile traffic, a large amount of vibration is generated daily due to cars driving over imperfectly level roads, and a vibration energy harvester can convert this energy into electrical energy, thus providing energy for devices such as bridge health sensors. However, the traditional single degree of freedom magnetic levitation vibration energy harvester (SMEH) has the disadvantage of low output power, so this research designs an improved dual degree of freedom magnetic levitation vibration energy harvester (DMEH), and a mathematical model of the energy harvester is built for simulation tests and an optimization model based on NSGA-II algorithm is developed for optimizing the structural parameters of the energy harvester. The experimental results show that the maximum total output power of DMEH and SMEH on CSSBB1, CSSBB2 and CSSBB3 are 48.7 mW, 36.8 mW, 25.4 mW and 27.2 mW, 21.5 mW, 14.9 mW, respectively, and the minimum total magnet volumes of both on CSSBB1, CSSBB2 and CSSBB3 are 268 cm3, 132 cm3, 219 cm3, 214 cm3, 86.2 cm3, 156 cm3. Based on the experimental data, it is found that the maximum output power of the optimal solution of DMEH is larger than that of SMEH for the selected simply supported girder bridge project, and the volume of the former is also larger than that of the latter, but the degree of increase can still be adapted to the application environment. The research results have some reference significance for improving the energy harvesting efficiency of bridge vibration energy harvesters.

Photovoltaics are systems that can convert sunlight into electrical energy. However, photovoltaic efficiency tends to be low, and its performance is affected by several environmental parameters such as dust, wind speed, humidity, temperature, and other external factors. Because there are many factors that can affect the power generated, we need a power output prediction system that can help in planning and managing as well as increasing the efficiency of photovoltaic systems. In this research, a system is designed that can predict the photovoltaic output power in the short term using the artificial neural network method or what is often called an artificial neural network. Predictions are made based on the effects of several environmental parameters such as wind speed, dust, humidity, and temperature on a 10 Wp photovoltaic system. Performance data for 7 days is used as a dataset and then processed using ANN with 1 input layer, 3 hidden layers, and 1 output layer, and 3 sample epochs (10, 100, and 1000). The results of the study can predict the output of photovoltaic power for the next 4 days with an error value of Mean Square Error (MSE) of 0.0010, Mean Absolute Error (MAE) of 0.0155, Root Mean Square Error (RMSE) of 0.0229 with an increase in power reaching 0.5 to 1 watt.

This study presents a novel solar updraft tower power plant (SUTPP) system, which has been designed to achieve the simultaneous utilization of solar and wind energy resources in desert regions, in response to the pressing demand for sustainable and efficient renewable energy solutions. The aim of this research was to develop an integrated system that is capable of harnessing and converting these abundant energy sources into electrical power, thereby enhancing the renewable energy portfolio in arid environments. The methodology of this study involved the design and construction of a prototype SUTPP, comprising a 53 m high tower, a 6170 m2 collector, five horizontal-axis wind turbines, and a thermal energy storage layer made up of pebbles and sand. The experimental setup was meticulously detailed, and experiments were conducted to collect data on the system’s performance under various environmental conditions. Subsequently, three-dimensional numerical simulations were performed to explore the effects of ambient wind speed and solar radiation on the output power of the SUTPP. The results indicate that the output power of the system increases with the increase in ambient wind speed and solar radiation. The impact of solar irradiation on output power was observed to diminish as ambient wind speeds increased. Notably, as the inlet wind speed rose from 4 m/s to 12 m/s, the output power showed a substantial increase of 727%. The numerical simulations revealed that ambient wind speed has a more pronounced effect on power output compared to solar radiation. Furthermore, it was found that the influence of solar radiation is significant at low wind speeds, with its impact decreasing as wind speed increases. This research provides essential guidance for the design and engineering of highly efficient solar thermal energy utilization projects, representing a significant advancement in the field of renewable energy technology deployment in desert environments.

Compared to the traditional wet-mate underwater power supply method, Magnetic Coupling Resonant Wireless Power Transfer (MCR-WPT) technology boasts advantages such as excellent insulation, high safety, and convenient operation, showing promising application prospects in the field of power supply for underwater vehicles and other mobile underwater devices. In order to explore the transmission characteristics of this technology underwater, this article first establishes a traditional mathematical model, and then modifies the underwater model through analysis of changes in coil self-inductance and mutual inductance, as well as the impact of eddy current losses. Using the modified mathematical model of the underwater MCR-WPT system, the transmission characteristics are analyzed, and simulations and experimental validations are performed using MATLAB R2022a software. In the study of frequency characteristics, it is found that the system operates optimally when both ends of the circuit work at the resonant state; that is, when finput = fresonance = 100 kHz, the output performance is at its best, and the optimal resonant frequency significantly improves power and transmission efficiency. When the input frequency is less than 87.3 kHz or greater than 122.9 kHz, the output power decreases to less than half of the maximum power. In the investigation of load effects, the optimal load for maximizing system output power was identified, but the load that maximizes transmission efficiency is different from this optimal load. This study provides strong theoretical support and guidance for improving the performance of underwater wireless power transmission systems.