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This paper focuses on the distributed generation (DG) controller of a PV-based microgrid. An independent DG controller (IDGC) is designed for PV applications to improve Maximum-Power Point Tracking (MPPT). The Extreme-Learning Machine (ELM)-based MPPT method exactly estimates the controller's reference input, such as the voltage and current at the MPP. Feedback controls employ linear PI schemes or nonlinear, intricate techniques. Here, the converter controller is an IDGC that is improved by directly measuring the converter duty cycle and PWM index in a single DG PV-based MG. It introduces a fast-learning Extreme-Learning Machine (ELM) using the Moore–Penrose pseudo-inverse technique and online sequential ridge methods for robust control reference (CR) estimation. This approach ensures the stability of the microgrid during PV uncertainties and various operational conditions. The internal DG control approach improves the stability of the microgrid during a three-phase fault at the load bus, partial shading, irradiance changes, islanding operations, and load changes. The model is designed and simulated on the MATLAB/SIMULINK platform, and some of the results are validated on a hardware-in-the-loop (HIL) platform. [ABSTRACT FROM AUTHOR]

Kilohertz‐frequency alternating currents (KFACs) have been indicated to minimize muscle atrophy and weakness. However, the optimal stimulation parameters still need to be determined. Objective: This study aimed to investigate the effects of different KFACs on evoked torque, current efficiency, and perceived discomfort. Design: KFACs with frequencies of 1 kHz (Aussie current) and 2.5 kHz (Russian current), along with two duty cycles (10% and 20%), were randomly applied to the triceps surae muscle of healthy participants using a crossover design. The NMES intensity, NMES‐evoked torque, NMES efficiency, and NMES discomfort were measured in maximal and submaximal conditions. Statistical analyses were conducted using a two‐way mixed‐model ANOVA with repeated measures. Forty‐four participants were included. Results: Aussie currents produced higher evoked torque and efficiency in maximal and submaximal efforts, with higher perceived discomfort in maximal effort. Although the Australian current may cause greater discomfort at maximal efforts, it matches the Russian current in perceived discomfort at submaximal levels. The 20% duty cycle produced the highest efficiency in submaximal efforts. Conclusion: In both maximal and submaximal efforts, the Aussie current demonstrated superior NMES efficiency, yielding higher torque with lower amplitude than the Russian current. Clinicians should take these findings into consideration when prescribing KFACs to optimize clinical outcomes. [ABSTRACT FROM AUTHOR]

Copyright of Current Retina Journal / Güncel Retina Dergisi is the property of Anadolu Kitabevi Basim Yayim Medikal Turizm Kirtasiye Tic. Ltd. Sti. 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 In this investigation, pulsed current electro-deposition (PCE) was used to prefabricate Ni–Co/SiC + TiN composite coatings (NCSTCCs) on mild steel surfaces. The research focused on the influence of two electrodeposition parameters, pulse frequency (PF) and duty cycle (DC), on NCSTCF features including microscopic surface morphology, crystal orientation, grain size, microhardness, SiC and TiN nanoparticles (NPs), deposition quantity, and corrosion resistance properties. The results indicated that NCSTCCs produced under a 10% DC showed minimal SiC and TiN contents with a percent volume of just 5.6 v/v% and 5.4 v/v% respectively under the fixed condition of 60 Hz PF. However, the three-dimensional surface diagram indicated that the Ni–Co/SiC + TiN composite film deposited at 50% DC and 10 Hz PF displayed the highest SiC and TiN contents (11.6 v/v% and 11.7 v/v%) among all the films. Furthermore, NCSTCCs deposited under 50% DC and 10 Hz PF had peak microhardness at 667.4 kg/mm2, while the composite film achieved a microhardness of 514.1 kg/mm2 when prepared using 10% DC and 60 Hz PF. Moreover, when the DC and PF were at 50% and 10 Hz respectively, the Ni–Co/SiC + TiN composite film presented the maximum charge transfer resistance (4915.7–4927.2 Ω·cm2), indicating an excellent corrosion resistance.

Copyright of Journal of Xi'an Jiaotong University is the property of Editorial Office of Journal of Xi'an Jiaotong University 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 minimization is crucial in designing Wireless Sensor Networks (WSNs), especially for multi-hop transmission. To address this challenge, an Intra-Cluster and Inter-Cluster (ICIC) energy reduction mechanism was developed, which includes dynamic duty cycle allocation for intra-cluster transmission and selection of the lowest Energy Consumption (EC) path for inter-cluster transmission. Conversely, randomly selecting Cluster Heads (CHs) can lead to inefficient distribution of tasks among nodes, impacting network lifetime. Additionally, small errors in the data received can lead to the Sink Node (SN) making an unsuccessful global decision in different WSN applications. Therefore, this manuscript introduces a new Progressive Index-Modulation (PIM)-based CH selection algorithm in ICIC (PIM-ICIC) for multi-hop WSNs. In this algorithm, a novel broadcasting scheme called index-shift is adopted to distribute the CH role more evenly among sensor nodes. First, Cluster Member (CM) nodes are divided into sets where nodes within the same set collaborate in selecting CHs to balance the CH loads. The CH is chosen according to the local cluster data in each cycle. If a node reaches a threshold limit for being chosen as a CH, an alternative node from a similar set can assume the CH role to transmit data to the SN. Thus, the PIM-ICIC algorithm can prolong network lifetime and reduce packet loss effectively. Finally, extensive simulations demonstrate that the PIM-ICIC achieves a Packet Delivery Ratio (PDR) of 5.8×105 packets, EC of 14J, and 20 dead nodes over 1000 rounds. With 400 nodes in the network, it achieves a PDR of 6.9×105 packets, 78% EC, and 86 dead nodes. At a 40dB Signal-to-Noise Ratio (SNR), PIM-ICIC achieves a Data Error Rate (DER) of 0.0002, surpassing ICIC, Hybrid Particle Swarm Optimization with Improved Low Energy Adaptive Clustering Hierarchy (HPSO-ILEACH), and Sine Cosine Algorithm with Levy mutation (SCA-Levy) in multi-hop WSNs. [ABSTRACT FROM AUTHOR]

Introduction: MRI-guided radiotherapy (MRgRT) allows for direct motion management and real-time radiation treatment plan adaptation. We report our institutional experience using low strength 0.35T MRgRT for thoracic malignancies, and evaluate changes in treatment duty cycle between first and final MRgRT fractions. Methods: All patients with intrathoracic tumors treated with MRgRT were included. The primary reason for MRgRT (adjacent organ at risk [OAR] vs. motion management [MM] vs. other) was recorded. Tumor location was classified as central (within 2cm of tracheobronchial tree) vs. non-central, and further classified by the Expanded HILUS grouping. Gross tumor volume (GTV) motion, planning target volume expansions, dose/fractionation, treatment plan time, and total delivery time were extracted from the treatment planning system. Treatment plan time was defined as the time for beam delivery, including multileaf collimator (MLC) motion, and gantry rotation. Treatment delivery time was defined as the time from beam on to completion of treatment, including treatment plan time and patient respiratory breath holds. Duty cycle was calculated as treatment plan time/treatment delivery time. Duty cycles were compared between first and final fraction using a two-sample t-test. Results: Twenty-seven patients with thoracic tumors (16 non-small cell lung cancer and 11 thoracic metastases) were treated with MRgRT between 12/2021 and 06/2023. Fifteen patients received MRgRT due to OAR and 11 patients received MRgRT for motion management. 11 patients had central tumors and all were treated with MRgRT due to OAR risk. The median dose/fractionation was 50 Gy/5 fractions. For patients treated due to OAR (n=15), 80% had at least 1 adapted fraction during their course of radiotherapy. There was no plan adaptation for patients treated due to motion management (n=11). Mean GTV motion was significantly higher for patients treated due to motion management compared to OAR (16.1mm vs. 6.5mm, p=0.011). Mean duty cycle for fraction 1 was 54.2% compared to 62.1% with final fraction (p=0.004). Mean fraction 1 duty cycle was higher for patients treated due to OAR compared to patients treated for MM (61% vs. 45.0%, p=0.012). Discussion: Duty cycle improved from first fraction to final fraction possibly due to patient familiarity with treatment. Duty cycle was improved for patients treated due to OAR risk, likely due to more central location and thus decreased target motion. [ABSTRACT FROM AUTHOR]

Iron–nickel (Fe-Ni) batteries are renowned for their durability and resilience against overcharging and operating temperatures. However, they encounter challenges in achieving widespread adoption for energy storage applications due to their low efficiency and the need for regular maintenance and electrolyte replacement, which adds to maintenance costs. This study evaluates and demonstrates the capabilities of Fe-Ni batteries for participating in grid energy storage applications. Stable performance was observed frequency regulation (FR) testing at 100% and 50% state of charge (SOC)s, while at 50% SOC, there was a 14% increase in efficiency compared to 100% SOC. Although 25% SOC achieved higher efficiency, limited cyclability was observed due to reaching the discharge cutoff voltage. Optimal SOC selection, battery monitoring, maintenance, and appropriate charging strategies of Fe-Ni batteries seem to be crucial for their FR applications. Fe-Ni batteries exhibit stable peak shaving (PS) results, indicating their suitability and reliability under various load conditions for PS testing. Extended cycling tests confirm their potential for long-term grid-scale energy storage, enhancing their appeal for PS and FR applications. [ABSTRACT FROM AUTHOR]

In this investigation, pulsed current electro-deposition (PCE) was used to prefabricate Ni–Co/SiC + TiN composite coatings (NCSTCCs) on mild steel surfaces. The research focused on the influence of two electrodeposition parameters, pulse frequency (PF) and duty cycle (DC), on NCSTCF features including microscopic surface morphology, crystal orientation, grain size, microhardness, SiC and TiN nanoparticles (NPs), deposition quantity, and corrosion resistance properties. The results indicated that NCSTCCs produced under a 10% DC showed minimal SiC and TiN contents with a percent volume of just 5.6 v/v% and 5.4 v/v% respectively under the fixed condition of 60 Hz PF. However, the three-dimensional surface diagram indicated that the Ni–Co/SiC + TiN composite film deposited at 50% DC and 10 Hz PF displayed the highest SiC and TiN contents (11.6 v/v% and 11.7 v/v%) among all the films. Furthermore, NCSTCCs deposited under 50% DC and 10 Hz PF had peak microhardness at 667.4 kg/mm2, while the composite film achieved a microhardness of 514.1 kg/mm2 when prepared using 10% DC and 60 Hz PF. Moreover, when the DC and PF were at 50% and 10 Hz respectively, the Ni–Co/SiC + TiN composite film presented the maximum charge transfer resistance (4915.7–4927.2 Ω·cm2), indicating an excellent corrosion resistance. [ABSTRACT FROM AUTHOR]

Copyright of Micronanoelectronic Technology is the property of Micronanoelectronic Technology 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.)

In the control system of permanent magnet synchronous motor, in order to improve real‐time performance and computational complexity, a new method of implementing segmented current control of permanent magnet motor using duty cycle modulation is proposed. The term plane is divided into three sectors through three‐phase voltage vector, and current prediction iteration is performed to obtain the relevant duty cycle, and the periodic modulation of this method (DM‐MPCC) is verified by experiments and the traditional DV‐MPCC (DV‐MPCC), the method is repeated more than 150 times, the time required for this method is 2.863 s, saving 52.073% of the computing time, while the modulation duty of DM‐MPCC It is also more stable than the waveform, and the current THD = 2.986% DM‐MPCC is much lower than the conventional method. DM‐MPCC has less pulsation on the dq axis at full speed than DV‐MPCC. The results show that the method has a faster operation speed and better real‐time performance, which shows the superiority of this method in practical applications. [ABSTRACT FROM AUTHOR]

The micro-arc oxidation (MAO) technique was employed to produce calcium phosphate coatings on titanium surfaces using an electrolyte composed of hydroxyapatite and calcium carbonate in an aqueous solution of orthophosphoric acid. The coatings' morphology and composition were regulated by adjusting electrical parameters, specifically the duty cycle and voltage. This study examined the effects of the duty cycle and voltage during the MAO process on the microstructure and composition of calcium phosphate coatings on VT1–0 titanium substrates. Scanning electron microscopy (SEM) was utilized to analyze the microstructure and thickness of the coatings, while X-ray diffraction (XRD) was employed to determine their phase composition. The findings reveal that the surface morphology of the calcium phosphate coatings transitions from a porous, sponge-like structure to flower-like formations as the duty cycle and voltage increase. A linear increase in the voltage within the applied duty cycles led to a rise in the size of the forming particles of amorphous/crystalline structures containing phases of monetite (CaPO3(OH)), monocalcium phosphate monohydrate (Ca(H2PO4)2·H2O), and calcium pyrophosphate (γ–Ca2P2O7). [ABSTRACT FROM AUTHOR]

Abstract Kilohertz‐frequency alternating currents (KFACs) have been indicated to minimize muscle atrophy and weakness. However, the optimal stimulation parameters still need to be determined. Objective This study aimed to investigate the effects of different KFACs on evoked torque, current efficiency, and perceived discomfort. Design KFACs with frequencies of 1 kHz (Aussie current) and 2.5 kHz (Russian current), along with two duty cycles (10% and 20%), were randomly applied to the triceps surae muscle of healthy participants using a crossover design. The NMES intensity, NMES‐evoked torque, NMES efficiency, and NMES discomfort were measured in maximal and submaximal conditions. Statistical analyses were conducted using a two‐way mixed‐model ANOVA with repeated measures. Forty‐four participants were included. Results Aussie currents produced higher evoked torque and efficiency in maximal and submaximal efforts, with higher perceived discomfort in maximal effort. Although the Australian current may cause greater discomfort at maximal efforts, it matches the Russian current in perceived discomfort at submaximal levels. The 20% duty cycle produced the highest efficiency in submaximal efforts. Conclusion In both maximal and submaximal efforts, the Aussie current demonstrated superior NMES efficiency, yielding higher torque with lower amplitude than the Russian current. Clinicians should take these findings into consideration when prescribing KFACs to optimize clinical outcomes.

Abstract The present working conventional power generation systems utilization is reducing day by day because of their demerits are more functioning cost, high carbon dioxide emission, more complexity in handling, and required high installation area. So, the current power generation company focuses on Renewable Energy Sources (RES) which are wind, tidal, and solar. Here, the solar power network is utilized for supplying electricity to the electrical vehicle battery charging system. The Solar photovoltaic (PV) modules supply nonlinear power which is not useful for automotive systems. To maximize the supply power of the solar PV system, an Adaptive Step Genetic Algorithm Optimized (ASGAO) Radial Basis Functional Network (RBFN) is utilized for tracking the working point of the solar PV module thereby enhancing the operating efficiency of the overall system. The features of this proposed hybrid Maximum Power Point Tracking (MPPT) controller are quick system dynamic response, easy operation, quick convergence speed, more robustness, and high operating efficiency when equalized with the basic MPPT controllers. The major issue of solar PV modules is low supply voltage which is increased by introducing the wide input voltage DC-DC converter. The merits of this introduced converter are low-level voltage stress on diodes, good quality supply power, high voltage gain, plus low implementation cost. Here, the introduced converter along with the AGAO-RBFN controller is analyzed by selecting the MATLAB/Simulink environment. Also, the proposed converter is tested with the help of a programable DC source.

In this presented study, we measured in situ the uplink duty cycles of a smartphone for 5G NR and 4G LTE for a total of six use cases covering voice, video, and data applications. The duty cycles were assessed at ten positions near a 4G and 5G base-station site in Belgium. For Twitch, VoLTE, and WhatsApp, the duty cycles ranged between 4% and 22% in time, both for 4G and 5G. For 5G NR, these duty cycles resulted in a higher UL-allotted time due to time division duplexing at the 3.7 GHz frequency band. Ping showed median duty cycles of 2% for 5G NR and 50% for 4G LTE. FTP upload and iPerf resulted in duty cycles close to 100%. [ABSTRACT FROM AUTHOR]

In this paper, Cu thin films were deposited on Si (100) substrates by the high−power impulse magnetron sputtering (HiIPMS) technique, and the effects of different duty cycles (from 2.25% to 5.25%) on the plasma discharge characteristics, microstructure, and electrical properties of Cu thin films were investigated. The results of the target current test show that the peak target current remains stable under 2.25% and 3% duty cycle conditions. Under the conditions of a 4.5% and 5.25% duty cycle, the target peak current shows a decreasing trend. The average power of the target shows a rising trend with the increase in the duty cycle, while the peak power of the target shows a decreasing trend with the increase in the duty cycle. The results of OES show that with the increase in the duty cycle, the total peak intensity of copper and argon emissions shows an overall increasing trend. The duty cycle from 3% to 4.5% change in copper and argon emission peak total intensity change is not obvious. The deposition rate and surface morphology of the copper film were investigated by scanning electron microscopy, and the deposition rate of the copper film increased with the increase in the duty cycle, which was mainly due to the increase in the average power. The surface roughness of the copper film was evaluated by atomic force microscopy. X−ray diffraction (XRD) was used to analyze the grain size and texture of the Cu film, and the results showed that the average grain size of the Cu film increased from 38 nm to 59 nm on the (111) and (200) crystal planes. Four−probe square resistance test copper film resistivity in 2.25%, 3% low duty cycle conditions of the copper film resistivity is generally higher than 4.5%, 5.25% high duty cycle conditions, the copper film resistivity shows the trend of change is mainly affected by the copper film grain size and the (111) face of the double effect of the optimal orientation. The lowest resistivity of the copper film measured under the 4.5% duty cycle condition is 1.7005 μΩ·cm, which is close to the intrinsic resistivity of the copper film of 1.67 μΩ·cm. [ABSTRACT FROM AUTHOR]

This article presents an improved model of a high voltage gain DC-DC converter topology. The voltage gain of the proposed topology is extended using a newly structured cascaded boost converter with voltage doubler cells along with the Super Luo structure in the network. The ultimate aim is to improve the output voltage gain of the proposed converter to a higher level with a lower duty cycle. Additionally, the design considerations minimize the voltage stress of the components (diodes, capacitors, and semiconductor switches) compared to the conventional topology. Moreover, the proposed topology ensures a continuous input current to the structure. Mathematical modeling is developed using steady-state analysis, and the results are analyzed using the MATLAB/Simulink. Finally, the proposed converter provides a high gain, that is, 10, at a lower duty cycle of 0.32 with reduced voltage stress on the components. [ABSTRACT FROM AUTHOR]

In recent times, wireless sensor networks (WSNs) and their applications have exhibited a remarkable surge. These networks strive to devise and implement strategies that optimize network energy utilization, thereby extending their operational lifespan. An energy efficient network can be achieved using renewable source of energy and by controlling the duty cycle of nodes. The pivotal role of duty cycle in curtailing energy consumption in WSNs cannot be overstated. In this work, we introduce a novel duty cycle based futuristic clustering technique (DCBFCT) employing a nearest neighbor approach. This technique selectively induces sleep and awake modes in nodes, effectively minimizing the network's overall energy consumption and, consequently, prolonging its lifespan. It calculates optimal node duty cycle values based on distance. Results demonstrate a substantial reduction in energy consumption, exhibiting an improved network lifetime. Empirical results presented in this study not only affirm the effectiveness of DCBFCT but also contribute valuable insights toward the development of sustainable and resilient WSNs in the era of burgeoning sensor network applications. The experimentation is conducted using the MATLAB/Simulink tool, considering diverse cases. The scalability and versatility of DCBFCT make it suitable for deployment in real-world applications, ranging from environmental monitoring to industrial automation. [ABSTRACT FROM AUTHOR]

Titanium alloys have many excellent characteristics, and they are widely used in aerospace, biomedicine, and precision engineering. Meanwhile, titanium alloys are difficult to machine and passivate readily. Electrochemical grinding (ECG) is an ideal technology for the efficient–precise machining of titanium alloys. In the ECG process of titanium alloys, the common approach of applying high voltage and active electrolytes to achieve high efficiency of material removal will lead to serious stray corrosion, and the time utilized for the subsequent finishing will be extended greatly. Therefore, the application of ECG in the field of high efficiency and precision machining of titanium alloys is limited. In order to address the aforementioned issues, the present study proposed an efficient–precise continuous ECG (E-P-C-ECG) process for Ti–6Al–4V applying high-pulsed voltage with an optimized duty cycle and low DC voltage in the efficient ECG stage and precise ECG stage, respectively, without changing the grinding wheel. According to the result of the passivation properties tests, the ideal electrolyte was selected. Optimization of the process parameters was implemented experimentally to improve the processing efficiency and precision of ECG of Ti–6Al–4V. Utilizing the process advantages of the proposed process, a thin-walled structure of Ti–6Al–4V was obtained with high efficiency and precision. Compared to the conventional mechanical grinding process, the compressive residual stress of the machined surface and the processing time were reduced by 90.5% and 63.3% respectively, and both the surface roughness and tool wear were obviously improved. [ABSTRACT FROM AUTHOR]

The present work presents the design and implementation of a non-isolated DC/DC Boost converter, operating with a nominal load of 20 W, a constant output voltage of 24 V, and a variable input voltage of 12 ± 25%. The development was carried out in the Power Electronics laboratories of the Electromechanical Engineering program at Universidad Francisco de Paula Santander, following the proposed solution methodology. The results demonstrate that the implemented PI control system improves the dynamic response of the converter in closed loop compared to the open loop, with steady-state errors ranging from 1.66% (for a Vin of 9V) to 3.33% (for a Vin of 12V and 15V) relative to the desired 24 V output. The system successfully stabilizes the output voltage against different input voltage variations, highlighting the importance of control systems and simulation tools in the design and analysis of power electronics circuits. [ABSTRACT FROM AUTHOR]

Mathematical models are the base for unified methods of calculating and designing radio-electronic devices. The developed limiting continuous mathematical model of a DC/DC converter built using the SEPIC topology allows us to estimate the range of changes in currents flowing through the windings of the inductors and voltages on the capacitor plates, as well as determine their maximum and minimum values for various converter parameters, such as the power switching frequency key, fill factor, element values, etc. The research results show that the phase coordinates of the mathematical model tend to the real values of the currents and voltages of the converter when the switching frequency of the power switch is more than 200 kHz. A correspondence was established between the calculated values of the ripple ranges and the results obtained during modeling (with changes in the duty cycle and switching frequency of the power switch). [ABSTRACT FROM AUTHOR]

We propose a photonics scheme to generate rectified cosinusoidal shaped (RCS) and rectified sinusoidal shaped (RSS) microwave waveforms and the duty cycle of the generated waveforms can be freely tunable. In this proposed method, two cascaded Mach-Zehnder modulators (MZMs) with polarization sensitive characteristics are employed. By setting the rotation angle of polarization controller, phase shift of the phase shifters and modulation index of the front MZM's (modulation index of the rear MZM is unfixed) properly, the obtained RCS and RSS microwave waveforms with arbitrary duty cycle by the superposition of beating signals, can be seen as an approximation of the first three terms of the Fourier series expansion of the ideal waveforms. The detailed theoretical analysis and simulations are given. In the simulations, the duty cycle of 100%, 80% and 50% of the RCS and RSS microwave waveforms are successfully obtained. Also, fitting errors are introduced to measure the similarity between the generated waveforms and the ideal waveforms. Different from previous works, the RCS and RSS microwave waveforms can be both generated by our scheme and the duty cycle is freely tunable. Moreover, the modulation index of the rear MZM is unfixed, thus increasing the flexibility of the scheme. [ABSTRACT FROM AUTHOR]

The pulse-width modulation (PWM) variable spray system is the most widely used variable spray system in the world at present, which has the characteristics of a fast response, large flow adjustment range, and good atomization. Recently, the pressure fluctuation and droplet deposition uniformity of the PWM variable spray system caused by the intermittent spray mode of the nozzle have attracted more and more attention. In this study, a method for eliminating the inhomogeneity of ground deposition in low-frequency PWM variable sprays based on a staggered-phase drive mode was proposed, and a PWM variable spray system was built. The experimental results indicated that the pressure fluctuation amplitude upstream of the nozzle of the PWM variable spray system with the staggered-phase drive was reduced by 40.91%, and the dispersion rate of the pressure fluctuation was reduced by 62.78% (the initial pressure was 0.3 MPa, solenoid valve frequency was 5 Hz, and duty cycle was 50%). The PWM control parameters had a significant effect on the upstream pressure fluctuation (initial pressure > duty cycle > frequency). The droplet spectrum relative span of the staggered phased PWM variable spray system decreased by 24.83%, the coefficient of variation of the droplet particle size decreased by 4.40%, the particle size was more uniform, and the atomization effect was improved. The average deposition of droplets in the forward direction driven by the staggered phase was 4.87% greater than that in the same phase, and the variation rate decreased by 20.87%. The average deposition amount increased, and the deposition became more uniform. Staggered-phase spray control could effectively reduce the inhomogeneity of deposition in low-frequency PWM intermittent spraying. This research provides strong technical support for a precision variable spraying effect and droplet drift prevention. [ABSTRACT FROM AUTHOR]

This research comprehensively explores the synthesis of Co–Ni–TiO2 coatings employing a hybrid methodology that integrates sol-enhanced and pulse current electrodeposition techniques. The investigation examined the surface morphology and intrinsic properties of Co–Ni–TiO2 coatings, revealing the significant influence of pulse duty cycle variations on the characteristics of coatings. A detailed analysis indicates that a pulse duty cycle of 0.4 optimized the coating’s performance, offering superior attributes compared to other duty cycle settings. The study elucidates that lower duty cycles foster hydrogen evolution reactions on the cathode surface, culminating in the formation of a porous, needle-like coating structure. Conversely, higher duty cycles are found to mitigate the effects of material replenishment, thereby affecting the coating’s quality and performance. The findings of this investigation not only shed light on the critical relationship between the pulse duty cycle and the properties of Co–Ni–TiO2 coatings but also lay a foundational framework for the further refinement and optimization of these coatings for advanced applications.

IntroductionMRI-guided radiotherapy (MRgRT) allows for direct motion management and real-time radiation treatment plan adaptation. We report our institutional experience using low strength 0.35T MRgRT for thoracic malignancies, and evaluate changes in treatment duty cycle between first and final MRgRT fractions.MethodsAll patients with intrathoracic tumors treated with MRgRT were included. The primary reason for MRgRT (adjacent organ at risk [OAR] vs. motion management [MM] vs. other) was recorded. Tumor location was classified as central (within 2cm of tracheobronchial tree) vs. non-central, and further classified by the Expanded HILUS grouping. Gross tumor volume (GTV) motion, planning target volume expansions, dose/fractionation, treatment plan time, and total delivery time were extracted from the treatment planning system. Treatment plan time was defined as the time for beam delivery, including multileaf collimator (MLC) motion, and gantry rotation. Treatment delivery time was defined as the time from beam on to completion of treatment, including treatment plan time and patient respiratory breath holds. Duty cycle was calculated as treatment plan time/treatment delivery time. Duty cycles were compared between first and final fraction using a two-sample t-test.ResultsTwenty-seven patients with thoracic tumors (16 non-small cell lung cancer and 11 thoracic metastases) were treated with MRgRT between 12/2021 and 06/2023. Fifteen patients received MRgRT due to OAR and 11 patients received MRgRT for motion management. 11 patients had central tumors and all were treated with MRgRT due to OAR risk. The median dose/fractionation was 50 Gy/5 fractions. For patients treated due to OAR (n=15), 80% had at least 1 adapted fraction during their course of radiotherapy. There was no plan adaptation for patients treated due to motion management (n=11). Mean GTV motion was significantly higher for patients treated due to motion management compared to OAR (16.1mm vs. 6.5mm, p=0.011). Mean duty cycle for fraction 1 was 54.2% compared to 62.1% with final fraction (p=0.004). Mean fraction 1 duty cycle was higher for patients treated due to OAR compared to patients treated for MM (61% vs. 45.0%, p=0.012).DiscussionDuty cycle improved from first fraction to final fraction possibly due to patient familiarity with treatment. Duty cycle was improved for patients treated due to OAR risk, likely due to more central location and thus decreased target motion.

Abstract As of now, there are multiple types of renewable energy sources available in nature which are hydro, wind, tidal, and solar. Among all of that the solar energy source is used in many applications because of its features are low maitainence cost, less human power for handling, a clean source, more availability in nature, and reduced carbon emissions. However, the disadvantages of solar networks are continuously depending on the weather conditions, high complexity of the solar energy storage, and lots of installation place is required. So, in this work, the Proton Exchange Membrane Fuel Stack (PEMFS) is utilized for supplying the power to the local consumers. The merits of this fuel stack are high power density, ability to work at very less temperature values, efficient heat maintenance, and water management. Also, this fuel stack gives a quick startup response. The only demerit of PEMFS is excessive current production, plus very less output voltage. To optimize the current supply of the fuel stack, a Wide Input Operation Single Switch Boost Converter (WIOSSBC) circuit is placed across the fuel stack output to improve the load voltage profile. The advantages of the WIOSSBC are less current ripples, uniform voltage supply, plus good voltage conversion ratio. Another issue of the fuel stack is nonlinear power production. To linearize the issue of fuel stack, the Grey Wolf Algorithm Dependent Fuzzy Logic Methodology (GWADFLM) is introduced in this article for maintaining the operating point of the fuel cell near to Maximum Power Point (MPP) place. The entire system is investigated by utilizing the MATLAB software.

Pulsed current cathodic protection (PCCP) could be more effective than direct current cathodic protection (DCCP) for mitigating corrosion in buried structures in the oil and gas industries if appropriate pulsed parameters are chosen. The purpose of this research is to present the corrosion prevention mechanism of the PCCP technique by taking into account the effects of duty cycle as well as frequency, modeling the relationships between pulse parameters (frequency and duty cycle) and system outputs (corrosion rate, protective current and pipe-to-soil potential) and finally identifying the most effective protection conditions over a wide range of frequency (2–10 kHz) and duty cycle (25%-75%). For this, pipe-to-soil potential, pH, current and power consumption, corrosion rate, surface deposits and investigation of pitting corrosion were taken into account. To model the input-output relationship in the PCCP method, a data-driven machine learning approach was used by training an artificial neural network (ANN). The results revealed that the PCCP system could yield the best protection conditions at 10 kHz frequency and 50% duty cycle, resulting in the longest protection length with the lowest corrosion rate at a consumption current 0.3 time that of the DCCP method. In the frequency range of 6–10 kHz and duty cycles of 50%-75%, SEM images indicated a uniform distribution of calcite deposits and no pits on cathode surface.

The square wave polarisation technique and mathematical/electrochemical models were combined to investigate pitting corrosion of pipeline steel X100 under cathodic protection potential fluctuations with different duty cycles (δ). Mathematical equations were derived to describe the increased potential of the double-charge layer at the steel/solution interface, which increases density from 1100 mm−2 (δ = 10%) to over 6600 mm−2 (δ = 50%). However, an electrochemical model was developed to present the formation of an amorphous corrosion product layer, which reduces the number of local anodic corrosion areas and decreases pitting density when δ is higher than 50%.

Nowadays, wireless body area networks are the center of attention for patients’ health data monitoring. In these networks, the sensor nodes deal with the limited energy of batteries to provide sustainable services. Unlimited energy supply by energy harvesters in these nodes as complementary to batteries makes perform in a stable state. However, the harvested energy has an irregular and unpredictable rate. When the data sensed by the sensor is stable, the continuous activity of the energy-harvesting body node (EH-BN) is necessary. Also, it can fully discharge the EH-BN energy if the harvestable energy rate is low. Therefore, it is required that EH-BN to be in sleep and wake modes periodically to adjust the duty cycle for EH-BN. Reinforcement learning algorithms perform nicely in determining the duty cycle under uncertain conditions. Previous RL-based methods for determining the BN’s duty cycle have two fundamental problems: (1) BN suffers from the emergency packet loss or unnecessary frequent sleeping and waking, and (2) discretization of the problem space does not ensure the determination of the optimal duty cycle. This paper proposes a new method for determining the EH-BN’s duty cycle based on deep reinforcement learning (DRDC). The novelties of DRDC are as follows: (1) considers the change rate of data sensed by BN in addition to its energy to avoid the emergency packet loss and unnecessary frequent sleep/wake, (2) uses Deep Q-Network (DQN) with light neural network for accurately determining BN’s duty cycle, (3) applies a three-layer communication architectural model when there are extreme limitations in BN resources to preserve the memory constraints and computational power of EH-BN. In this architectural model, the algorithm is executed on a local server, and only the trained policy is transmitted to EH-BN. (4) designs a reward function to realize the suitable performance of the DQN algorithm. This function simultaneously depends on the EH-BN energy, change rate of the sensed data, and sleep time and can balance these parameters. Results of simulations suggest that the proposed method decreases the EH-BN duty cycle by about 28% and the data overhead by more than 50% on average relative to similar studies.

This paper focuses on the distributed generation (DG) controller of a PV-based microgrid. An independent DG controller (IDGC) is designed for PV applications to improve Maximum-Power Point Tracking (MPPT). The Extreme-Learning Machine (ELM)-based MPPT method exactly estimates the controller’s reference input, such as the voltage and current at the MPP. Feedback controls employ linear PI schemes or nonlinear, intricate techniques. Here, the converter controller is an IDGC that is improved by directly measuring the converter duty cycle and PWM index in a single DG PV-based MG. It introduces a fast-learning Extreme-Learning Machine (ELM) using the Moore–Penrose pseudo-inverse technique and online sequential ridge methods for robust control reference (CR) estimation. This approach ensures the stability of the microgrid during PV uncertainties and various operational conditions. The internal DG control approach improves the stability of the microgrid during a three-phase fault at the load bus, partial shading, irradiance changes, islanding operations, and load changes. The model is designed and simulated on the MATLAB/SIMULINK platform, and some of the results are validated on a hardware-in-the-loop (HIL) platform.

As of now, there are multiple types of renewable energy sources available in nature which are hydro, wind, tidal, and solar. Among all of that the solar energy source is used in many applications because of its features are low maitainence cost, less human power for handling, a clean source, more availability in nature, and reduced carbon emissions. However, the disadvantages of solar networks are continuously depending on the weather conditions, high complexity of the solar energy storage, and lots of installation place is required. So, in this work, the Proton Exchange Membrane Fuel Stack (PEMFS) is utilized for supplying the power to the local consumers. The merits of this fuel stack are high power density, ability to work at very less temperature values, efficient heat maintenance, and water management. Also, this fuel stack gives a quick startup response. The only demerit of PEMFS is excessive current production, plus very less output voltage. To optimize the current supply of the fuel stack, a Wide Input Operation Single Switch Boost Converter (WIOSSBC) circuit is placed across the fuel stack output to improve the load voltage profile. The advantages of the WIOSSBC are less current ripples, uniform voltage supply, plus good voltage conversion ratio. Another issue of the fuel stack is nonlinear power production. To linearize the issue of fuel stack, the Grey Wolf Algorithm Dependent Fuzzy Logic Methodology (GWADFLM) is introduced in this article for maintaining the operating point of the fuel cell near to Maximum Power Point (MPP) place. The entire system is investigated by utilizing the MATLAB software. [ABSTRACT FROM AUTHOR]

In this paper, a light-emitting diode (LED) driver with a high power factor (PF) and low-frequency current ripple suppression over a wide input range is presented, and a flyback converter is designed to operate in the discontinuous conduction mode (DCM), with a digital controller used to keep the duty cycle constant for half of the utility cycle under a fixed load and input voltage. This method ensures that the input current is in phase with the universal input voltage, thus achieving a high power factor without utilizing feedforward control. Furthermore, on the secondary side, the time of the zero point of the utility voltage can be attained so that the duty cycle can be updated at this time. In addition, a simple auxiliary circuit is connected parallel to the output side to absorb the excess output current of the flyback converter or to release the current to the load to make up for the shortage of the output current of the flyback converter so that the low-frequency ripple of the output current can be inhibited. There are only two current-detecting resistors used in this study: one is the output current-sensing resistor of the flyback converter, and the other is the output current-sensing resistor of the auxiliary circuit. [ABSTRACT FROM AUTHOR]

Cutting force is an important factor that affects the surface quality of machining carbon fiber-reinforced polymer (CFRP). High cutting force can lead to surface damage such as the burrs and the delamination in the machining process of CFRP. Ultrasonic vibration-assisted machining (UVAM) can reduce the cutting force in the machining process. This work is focused on the relationship between the duty cycle and the cutting force in UVAM of CFRP. Based on the kinematics of UVAM, the movement of the cutting tool edge and the tool–workpiece separation in UVAM were analyzed, and a calculation formula for the duty cycle was obtained. The milling experiment of CFRP was conducted to compare the cutting force between UVAM and conventional machining (CM), and the relationship between the reduction in the cutting force in UVAM and the duty cycle was determined. The experimental results showed that when the duty cycle was 0.2916, the cutting force of UVAM was reduced by 7.4% to 27% compared with that of CM. When the duty cycle was 1, the cutting force of UVAM was reduced by −4.5% to 7.5% compared with that of CM. Therefore, the effect of reducing the cutting force of UVAM can be enhanced by adjusting the process parameters to reduce the duty cycle of UVAM, and a lower cutting force can be obtained. [ABSTRACT FROM AUTHOR]

The characteristic effects of a permanent magnet brushless dc (PMBLDC) motor which is propelled by a quadratic DC–DC boost converter was investigated in this paper. The boost converter applied inductor coupling with semi-conductor switches which operate concurrently to produce a high conversion voltage ratio. Modeling of the PMBLDC motor was presented while simulation was performed using a closed loop control system with different controllers for the enhancement of torque–speed performance at varied load. Simulation results show that an optimum voltage gain with minimum voltage stress was achieved at 0.9 duty cycle while varying the inductor turns ratio (n) from 1 to 6 and inductor coupling coefficient (K) from 0.1 to 1.0 so as to ensure that the entire flux generated in one coil is fully linked to the other. A simplified PI controller was designed and experimented through simulation for excellent drive performance at varying load. The results from the spectral display show that the usual speed oscillation and torque ripples produced by the machine were attenuated using different speed controllers. The Total Harmonic Distortion (THD) values indicate that the PID controller achieved a minimal value of 24.06% for speed and 23.16% for torque as compared to 28.73% and 29.82% obtained from the PI controller, while the P controller achieved 41.88% and 35.67% as shown in the graphical abstract. [Display omitted] • Star-connected trapezoidal back-EMF brushless DC motor propelled by a semi-quadratic DC–DC boost converter (SQBC) was modeled and simulated. • For an effective proof of concept, a computer simulation was carried out to demonstrate the level of torque ripples. • The PID-controller provided a minimum value of 24.06% for the speed and 23.16% for the torque, according to the THD data. • 41.88% and 35.67% were reached using the P-Controller, while 82% was achieved using the PI-Controller. [ABSTRACT FROM AUTHOR]

This article deals with the characterization of photovoltaic (PV) panels using current-voltage (I–V) tracers. It focuses on the realization of a low cost and real-time I–V tracer that uses an inexpensive DC/DC converter, a fixed load and sensors for measuring current and voltage of the PV Panel. Additionally, a data acquisition interface (DAI) is developed to collect real-time PV data under different weather conditions. The developed tracer reduces testing time for PV panel characterization compared with classical methods. In order to evaluate the performance of the developed tracer, we analyze the electrical parameters to which the electronic equipment is exposed and contrasts the advantages of the suggested technique and disadvantages of the classical method of measurement (i.e., using multimers), taking a variety of criteria including accuracy into account. For further validation, we compare the experimental PV characteristics to the simulated PV curves obtained using a single diode model. [ABSTRACT FROM AUTHOR]

The present investigation aims to shed light on the efficiency of the irradiation-based advanced oxidation processes using controlled pulsed illumination (CPI) in a homogeneous process. A more in-depth emphasis has been applied considering the ultraviolet-light emitting diodes/persulfate (LED/S2O82−) system. Irradiation-driven processes can present unexpected behaviour under a pulsed irradiation compered to continuous irradiation. This behaviour can be explained by Parrando's paradox concept. The removal efficiency of organic dyes under a continuous illumination source was compared to the CPI system employing a pulsed UV-LED/S2O82− photoreactor to explore CPI performance. The efficiency of the pulsed UV-LED/PS method was investigated using three organic dyes as model pollutants and duty cycle and pulse period as parameters of the pulsed irradiation source. The duty cycle and pulse period have a crucial impact on the pulsed system efficiencies, which were studied in the values of 10 %, 25 %, 50 %, 75 %, 90 %, and 99 % for pulse periods from 1 ms (ms) to a few hundred ms in the current study. For all experiments, the electrical energy consumption (EEO) values were calculated, and the CPI values were compared to the continuous illumination values. According to the results, duty cycles and pulse periods of (10 %, 800 ms), (10 %, 1 ms), and (10 %, 800 ms), with the EEO amounts of 58.29, 120.65, and 29.62 kWh per order showed the best performance for the removal of organic dyes, respect to continuous irradiation and other CPI experiments in terms of saving energy. Besides, the game theory and the collision hypothesis were scrutinized to justify the achieved results.

Pengukuran dan pengendalian ketinggian cairan masih dilakukan secara direct, menggunakan saklar atau sensor yang bersifat logic saja. Dengan konsep kontrol ini membutuhkan lebih banyak waktu, dan tidak secara real-time. Penelitian ini bertujuan untuk membuat dan merancang sistem kendali level cairan pada tangki menggunakan PLC Siemens S7-1200 sebagai pusat kontrol dan HMI KTP 700 BASIC sebagai pusat kendali dan monitoring level cairan pada tangki. Metode perancangan system yang digunakan dalam penelitian terdiri dari perancangan hardware dan software. Perancangan hardware terdiri dari PLC Siemens S7-1200 sebagai pusat kontrol, water pump sebagai penyuply cairan dan potensiometer difungsikan sebagai sensor yang akan membaca ketinggian cairan serta HMI Siemens KTP 700 Basic digunakan untuk interface pembacaan hasil ketinggian secara digital. Driver motor dengan konsep PWM (Pulse Width Modulation) digunakan untuk mengatur kecepatan pompa dengan memvariasikan duty cycle motor yang dimanfaatkan untuk mengisi air kedalam tangki. Serial komunikasi antara PC, PLC dan HMI menggunakan ethernet switch. Pengujian dilakukan dengan lima cara, pertama pengujian potensiometer, kedua pengujian akurasi tegangan potensiometer terhadap ketinggian level air, ketiga pengujian PWM, keempat pengujian sistem tanpa gangguan, dan kelima pengujian sistem dengan gangguan. Dari pengujian pertama didapatkan hasil bahwa nilai rata-rata dari error sensor sebesar 0.005714 %. Dengan demikian penelitian ini mendapatkan hasil alat sistem kendali dan monitoring level cairan berbasis PLC dan HMI dengan error rata-rata sebesar 9.5 detik serta memiliki kemampuan terbaik untuk pompa pada set point 70 %.

Iron–nickel (Fe-Ni) batteries are renowned for their durability and resilience against overcharging and operating temperatures. However, they encounter challenges in achieving widespread adoption for energy storage applications due to their low efficiency and the need for regular maintenance and electrolyte replacement, which adds to maintenance costs. This study evaluates and demonstrates the capabilities of Fe-Ni batteries for participating in grid energy storage applications. Stable performance was observed frequency regulation (FR) testing at 100% and 50% state of charge (SOC)s, while at 50% SOC, there was a 14% increase in efficiency compared to 100% SOC. Although 25% SOC achieved higher efficiency, limited cyclability was observed due to reaching the discharge cutoff voltage. Optimal SOC selection, battery monitoring, maintenance, and appropriate charging strategies of Fe-Ni batteries seem to be crucial for their FR applications. Fe-Ni batteries exhibit stable peak shaving (PS) results, indicating their suitability and reliability under various load conditions for PS testing. Extended cycling tests confirm their potential for long-term grid-scale energy storage, enhancing their appeal for PS and FR applications.