Power Recovery Research Articles

Applications of H2-Enriched syngas and slag products from plastic wastes via novel plasma dual-stage-arc pyrolysis

Sustainable plastic waste management in the prevailing ‘new-normal’ post-pandemic scenario calls for calorific waste plastic up-cycling into high-end product recovery pathways. The present work employed a novel dual-stage arc plasma pyrolysis reactor to recover syngas and slag products from mixed plastics and Low-Density Polyethylene and Polyethylene Terephthalate (LDPE-PET) plastic waste feeds. Syngas product yield decreased while the solid slag yield increased with rising arc current, attaining 75% and 25% for mixed plastic waste feed and 59% and 41% for LDPE-PET wastes, respectively, at 200A arc current. The resultant syngas composition showed 83% and 77% H2 while 1.7% and 2.7% CO for mixed plastic waste-feed and LDPE-PET wastes, respectively, with no significant presence of CO2. Slag characterization studies revealed the presence of scattered pores on the slag surface, graphitic nanostructures due to scraped carbon depositions from electrode tips and the absence of aromatic groups due to complete conversion. High carbon content was observed in the slag due to the dissociation of lighter hydrocarbon and carbon dioxide on dual-arc exposure in two stages, underscoring the higher efficiency. For holistic integrated circular onsite ‘plastic waste-to-resource’ recovery-cum-application, electricity was generated from the resultant syngas and the slag was used for the manufacture of tiles in the community platform. Techno-economic evaluation of an up-scaled plasma pyrolysis facility shows the power recovery of 3.5 kWh/kg of waste plastic, with a net annual profit of $2800 and a payback period of 1.7 years. The findings of the present work suggest that the proposed integrated dual-arc plasma pyrolysis based plastic waste-to-resource recovery in circular-economy model has a viable outcome.

Reversal of Denervation Changes in Infraspinatus Muscle After Operative Management of Paralabral Cysts: An MRI-Based Study.

Paralabral cysts at the spinoglenoid notch are rare disorders that can potentially lead to compressive suprascapular neuropathy. Given their infrequency, a standard treatment protocol has not yet been established. This study aimed to assess changes in the infraspinatus muscle using magnetic resonance imaging (MRI) and to compare the outcomes of 2 different surgical methods. It was hypothesized that surgical intervention could alleviate compressive neuropathy, with comparable outcomes between the 2 surgical approaches. Cohort study; Level of evidence, 3. This retrospective review encompassed 43 patients undergoing arthroscopic labral repair for a paralabral cyst at the spinoglenoid notch, with cyst decompression (27 patients; labral repair with cyst decompression [LRCD] group) or without cyst decompression (16 patients; labral repair only [LRO] group). Preoperative MRI focused on evaluating the condition of the infraspinatus and teres minor muscles. Electromyography (EMG) was conducted on 36 patients (21 in LRCD and 15 in LRO) to assess suprascapular nerve function. Postoperative evaluations were performed in 35 patients at postoperative 1 year, excluding those lost to follow-up. Postoperative MRI findings (24 patients in LRCD and 11 patients in LRO) and functional outcome scores including recovery of external rotation power were compared with preoperative status in both groups. Preoperative MRI revealed denervation changes or atrophy of the infraspinatus in 26 of the 43 patients (60.4%). Among the 36 patients who underwent preoperative EMG, 21 patients (58.3%; 13 patients in LRCD and 8 patients in LRO) showed evidence of suprascapular neuropathy. A discrepancy between EMG and MRI findings was noted in 10 patients, with 5 patients showing suprascapular neuropathy according to EMG despite normal muscle status on MRI scans, and the remaining 5 vice versa. Notable atrophy of the infraspinatus was seen in 6 patients and teres minor hypertrophy in 5 patients, all of whom exhibited concurrent infraspinatus atrophy. Postoperatively, cyst disappearance was observed in all cases in both LRCD (24 patients) and LRO (11 patients) groups. Denervation changes in the infraspinatus were resolved in all patients. In patients with infraspinatus atrophy, some improvement was noted. Teres minor hypertrophy persisted in 2 of 4 patients. Improvements were similar in both groups (all P > .05). External rotation power improved postoperatively in both groups (from 39.1 ± 18.6 to 50.6 ± 17.7 N in LRCD, P < .001; from 45.1 ± 16.0 to 54.2 ± 10.7 N in LRO, P = .025). Both LRCD and LRO surgical approaches appear to be effective for paralabral cysts at the spinoglenoid notch. Suprascapular neuropathy can be successfully addressed by both methods. However, conditions with severe infraspinatus atrophy and teres minor hypertrophy warrant further investigation in larger series.

Recovery of electrical power from exhaust air—role of vertical axis wind turbine

AbstractThis article explores the potential of regeneration of power from unnatural wind sources with the help of vertical axis wind turbines (VAWT). Researchers are searching for urban as well as industrial wind sources, which can be useful as the natural wind source to obtain electrical energy and utilize it. The wind sources considered here are the exhaust of the cooling or ventilation fans used in buildings, industries, and other places. The Darrieus VAWT extracts wind power from the exhaust air and reduces the power consumption of the concerned electrical drives. These uncommon energy sources have an inherent capability to recover a significant amount of energy without polluting the environment with less payback period. Recovered energy can be suitably converted into electrical energy and may be fed back to the power grid without any pollution, thus minimizing the total energy consumption of the building and reducing the cost operations. A detailed study of experimental models with different types of assembly and turbine models is conducted here with power outputs and operational behaviors on the existing systems. Various parameters and factors for existing and new applications are in detail that show the system has no negative impact on regular operation.

Self-Repeatable snapping liquid–crystal-elastomer actuator

Liquid crystal elastomers (LCEs) show potential for use in sensors and robotics owing to their reversible stimuli response. However, current actuators have limitations such as low power and slow recovery. Incorporating snap-through transitions induced by mechanical instability into motion can enhance the speed and power of soft actuators. However, the snap-through transitions’ single-shot motion response without external assistance at complicates their application to continuous and self-repeatable actuation. This study introduces a promising and simple approach for creating a rapid and self-repeatedly regulated snapping motion in an LCE actuator by confining the LCE film in a frame. We explore the confinement effect of a freestanding pre-curved LCE film that smoothly changes its bending direction and shows anticlastic buckling. Interestingly, a self-repeating snapping motion is generated by attaching a rigid film onto the LCE film, thereby inducing synclastic deformation. Remarkably, the up-and-down bending snapping motion occurs at a very high speed (within 30 ms) and is self-regulated depending on the temperature of the bottom surface. By utilizing this thermally responsive snapping LCE actuator, we successfully demonstrate an organic-based novel fire alarm and a self-propelled soft-walk mechanism.

Unsteady aerodynamic interaction in regulated two-stage radial turbine at pulsating conditions

Regulated multi-stage turbocharging is an indispensable technology to achieve high boosting pressure and hence power recovery for High-Altitude Long-Endurance Unmanned Aerial Vehicle (HALE UAV). Inevitably, unsteady interstage coupling has become a key factor restricting the pursuit of higher aerodynamic performance in multi-stage turbochargers. This study is to investigate the unsteady gasdynamic behavior of two-stage radial turbines and aimed to obtained the knowledge of unsteady aerodynamic interaction at pulsating conditions. Results reveal an obvious difference in the performance discrepancy mechanisms of high-pressure turbine (HPT) and low-pressure turbine (LPT). HPT shows more unsteady than that of LPT according to the discussion on mass accumulation and local temporal gradient. Furthermore, this unsteadiness is drastically enhanced when the valve is open. For HPT with open valve, a sharp reduction of up to 10.7% in the cycle-averaged efficiency is observed. Both the volute and the rotor are the main components causing the deterioration of efficiency. Swirling flow precession leads to a dramatically loss generation in the volute. Leading-edge separation and tip leakage flow are the dominated factors in rotor. The former is primarily attributed to inlet swirling flow and the latter is predominantly attributed to the pulsating effect. For LPT, the performance is not sensitive to the valve state, with no more than 3% discrepancy on efficiency. At specific velocity ratio, the negative swirling flow tends to exert a positive effect to the rotor efficiency, whereas the positive swirling flow leads to a higher entropy generation in rotor passage.

Comprehensive analysis of waste heat recovery and thermal energy storage integration in air conditioning systems

The proposed work aims to address the challenge of effectively recovering and storing wasted heat in air conditioning (AC) systems, which is crucial for improving energy efficiency and system stability. This study focuses on the comprehensive analysis of a Waste Heat Recovery (WHR) system integrated with Thermal Energy Storage (TES) tanks. A lumped-dynamic thermal model was developed and validated against literature data to accurately simulate the system’s performance. Through a detailed parametric study, the research explores how factors like WHR effectiveness, TES type, PCM type, and TES volume influence the system. The results demonstrate that recovering and storing wasted heat from AC systems significantly enhances operational stability and performance. Notably, increasing WHR effectiveness from 0.55 to 0.85 extends the duration of constant thermal power recovery and also results in higher recovered water temperatures with reduced water pump energy consumption. Furthermore, latent heat storage (PCM tank) extends the duration of stable thermal power recovery by over 61 % compared to sensible storage. Using PCM RT 44HC is more effective for WHR in AC units compared to RT 50 and RT 54HC. Finally, it was shown that increasing PCM tank volume from 2 to 4 m3 improves the duration of constant thermal power recovery by up to 52 % while stabilizing the recovered water temperature.

Alkali alkanoate ionic liquids for thermal energy storage at mid-to-high temperature: Synthesis and thermal–physical characterization

Thermal energy storage is gaining much attention and experiencing a renascence in last years. In this sense, storing thermal energy in form of latent heat is of special interest due higher energy density, lower energy losses and higher energy efficiency. To store thermal energy as latent heat the presence of a phase change material (PCM) is needed and its performance the key for its implementation in a thermal energy storage (TES) system and the temperature at which the phase change takes place, low (<150 °C) or high (>150 °C) temperature, will condition the application of a given PCM. In this context, the development of PCM materials to store latent heat at mid-to-high temperature in between 150 °C and 350 °C is of special interest e.g., in the field of concentrated solar power or heat recovery. There are already some solid–liquid phase change materials working in this range of temperature e.g., sugar alcohols, aromatic organic compound, inorganic salts, or blend of inorganic salts but all of them present different drawbacks, such as vapor pressure, degradation, low thermal conductivity, corrosion, etc. In consequence, there is a need to explore new PCM materials in this range of temperature applications. In this context, ionic liquids could play a key role in the development of novel PCMs due to their intrinsic properties. Indeed, ILs are gaining increased attention in the field of thermal energy storage in the last years but mainly in the low temperature range (<150 °C) remaining their application in the mid-to-high temperature range in between 150 °C and 350 °C underestimated. In this work, we prepared six different alkali alkanoate ionic liquids, namely [Na][MeOC2], [K][MeOC2], [Na][MeOC3], [K][MeOC3], [Na][MeOC4] and, [K][MeOC4] by direct reaction between the desired methyl methoxycarboxylate ester with NaOH or KOH. The prepared ionic liquids were structurally characterized, and their thermal–physical properties evaluated. Five of them but [K][MeOC3] showed good enthalpy values ranging from 119 J/g to 197 J/g and four of them [Na][MeOC2], [K][MeOC2], [Na][MeOC4] and, [K][MeOC4] have showed excellent thermal stability above 380 °C. In addition, these four ionic liquids have successfully passed the cyclability test showing no significant enthalpy losses (between 0 % minimum and 7 % maximum) after 50 heating/cooling cycles compiling with the cycling category F of the RAL-GZ 896 (Quality Association PCM). All in all, these prepared ionic liquids surpass sugar alcohols in terms of cyclability and thermal stability and are comparable with the inorganic salts e.g. NaNO3 employed in the studied range of mid-to-high temperature (150–350 °C).

Voltage optimal control model of regional distribution network after reconfiguration based on multi-energy conversion

In the event of a significant operational fault in the regional distribution network connected to the distributed new energy generator set, it may be necessary to quickly reconfigured certain areas of the system. This process must ensure minimal impact on the voltage of the regional distribution network. To address this issue, a voltage optimal control strategy for regional distribution network based on multi-energy conversion is proposed. Firstly, the energy conversion and adjustable characteristics of electricity, heat, and gas energy conversion equipment in the regional distribution network are analyzed in this paper. The steady-state operation model of the regional distribution network with multi-energy conversion is established. Then, the voltage optimal control model for rapid reconfiguration of the multi-energy distribution network is established by considering the two optimization objectives of power recovery for the important load and system voltage fluctuation. The model is solved based on the greedy algorithm. Finally, an equivalent model of the regional distribution network with multi-energy conversion equipment access is built based on the operation data of the distribution network in a certain area of Northeast China. The feasibility and effectiveness of the model are analyzed and verified.

A shape-stable phase change material for high-temperature thermal energy storage based on coal fly ash and Na2SO4-K2SO4

Using coal fly ash (CFA) as the skeleton material and binary sulfates of Na2SO4-K2SO4 as the phase change material (PCM), high-temperature coal fly ash based phase change thermal storage materials (CPCM) were successfully synthesized. The influences of CFA fractions and types on the morphology, physicochemical properties, and thermal characteristics of the composites were intensively investigated. Results show that the heat storage density and thermal conductivity of CPCMs increase with the PCM content. Particularly, the CPCM60-A composite, comprising 60 wt% Na2SO4-K2SO4 eutectic and 40 wt% CFA-A, exhibits excellent chemical compatibility and stable shape retention after sintering. Furthermore, CPCM60-A demonstrates the highest phase change latent heat of 60.43 J/g and thermal conductivity of 0.61 W/(m·K). The influence of CFA types reveals that CFA-A with a higher ratio of SiO2 and Al2O3, lower carbon content, and a rich porous structure is more suitable to fabricate molten salt heat storage materials. This work demonstrates that CFA, a byproduct of coal-fired industry, is a promising skeleton material for the fabrication of high-temperature CPCM composites, offering a novel approach for enhancing the efficiency and cost-competitiveness of solar power and waste heat recovery systems.

Bionanocomposite materials for electroanalytical applications: current status and future challenges.

Bionanocomposites are materials composed of particles with at least one dimension in the range of 1-100 nm and a constituent of biological origin or biopolymers. They are the subject of current research interest as they provide exciting platforms and act as an interface between materials science, biology, and nanotechnology and find applications in disciplines such as electrochemistry, biomedicine, biosorption, aerospace, tissue engineering and packaging. They have different properties such as high conductivity, thermal stability, electrocatalytic ability, biocompatibility, adsorption ability and biodegradability, which can be tuned by their preparation methods, functionalities and applications. However, depending on the objective or the goal of a research project, specific preparation and characterization of bionanocomposites can be undertaken to understand the behavior and confirm the applicability of a bionanocomposite in a given field. Like in electroanalysis applications, electrode materials should be porous (meso- and macro-porosities), having large specific area (at least having a Brunauer-Emmett-Teller surface of 200 m2 g-1), higher stability over time with acceptable power recovery between 95% and 105%, good electrocatalytic ability, and be a good absorbent and a good conductor of electricity (that is to say, it facilitates the transfer of electrons from the solution to the surface of the electrode and vice versa). The present review focuses on the most used method of preparation of bionanocomposites with the critical aspect and their physicochemical and electrochemical characterization techniques, and finally, the practical situations of application of bionanocomposite materials as modified electrodes for electroanalysis of several groups of analytes and a comparison with non-bionanocomposite electrodes are discussed. The future scope of bionanocomposites in the field of electroanalysis is also addressed in this review. But before that, a general overview of bionanocomposite materials in relation to other types of materials is presented to avoid any misunderstanding.

Improved bioenergy recovery and desalination efficiency using innovative configuration of an upflow triple enclosed cuboid compartments -photosynthesis microbial desalination cell: Experimental and modeling study

Performance of an innovative configuration of enclosed cuboid compartments-photosynthesis microbial desalination cell (EC-PMDC) for synchronous sewage treatment, desalination of seawater, and renewable energy recovery. Bioanode and biocathode were inoculated with jumbled bacterial species and mixed microalgae, respectively. The results demonstrated that maximum removal efficiency of organic content as chemical oxygen demand (COD) from the sewage was up to 99 %, whereby the total dissolved solids (TDS) removal efficiency from seawater was 91 %, accompanied with maximum power generation of 975 mW/m3. Kinetic study of bacterial growth in the EC-PMDC demonstrated excellent agreement between experimental data and those predicted by Blackman, Monod, Moser, and Teissier models with coefficients of determination (R2) equal to 0.98, 0.97, 0.96, and 0.97, respectively. Significant harmonization was obtained between the experimental results of voltage, current density, and power density with those predicted by the adopted electrochemical model. For comparison purposes, a conventionally designed photosynthesis microbial desalination cell (SC-PMDC) consisted of triple sequential cuboid compartments was setup. It was fed with similar influents as for the EC-PMDC. Maximum efficiencies of COD and TDS removals were 99 % and 81 %, respectively accompanied with power recovery of 420 mW/m3 were observed in the SC- PMDC indicating the superiority of EC-PMDC design.

Electrophysiological activity pattern of mouse hippocampal CA1 and dentate gyrus under isoflurane anesthesia.

General anesthesia can impact a patient's memory and cognition by influencing hippocampal function. The CA1 and dentate gyrus (DG), serving as the primary efferent and gateway of the hippocampal trisynaptic circuit facilitating cognitive learning and memory functions, exhibit significant differences in cellular composition, molecular makeup, and responses to various stimuli. However, the effects of isoflurane-induced general anesthesia on CA1 and DG neuronal activity in mice are not well understood. In this study, utilizing electrophysiological recordings, we examined neuronal population dynamics and single-unit activity (SUA) of CA1 and DG in freely behaving mice during natural sleep and general anesthesia. Our findings reveal that isoflurane anesthesia shifts local field potential (LFP) to delta frequency and reduces the firing rate of SUA in both CA1 and DG, compared to wakefulness. Additionally, the firing rates of DG neurons are significantly lower than CA1 neurons during isoflurane anesthesia, and the recovery of theta power is slower in DG than in CA1 during the transition from anesthesia to wakefulness, indicating a stronger and more prolonged impact of isoflurane anesthesia on DG. This work presents a suitable approach for studying brain activities during general anesthesia and provides evidence for distinct effects of isoflurane anesthesia on hippocampal subregions.

Effect of Cold vs Temperate Conditions on Physical Performance During Extended Mountain Warfare Training at Moderate Altitude.

The purpose of this study was to investigate the effect of environmental conditions on body composition, upper body power, and lower body power throughout a ∼4-week military mountain training exercise. We hypothesized that countermovement jump and ballistic push-up performance would decrease as a result of extended mountain field training and that winter (cold) conditions would result in greater decrements compared to fall (temperate) conditions. We also expected to observe a strong positive correlation between changes in performance and changes in skeletal muscle mass. Finally, we expected acute changes in performance upon altitude exposure. A total of 111 U.S. Infantry Marines (110 M; 1 F) provided written informed consent to participate in this study according to a protocol approved by the Naval Health Research Center. There were 54 participants in the fall cohort and 57 in the winter cohort. Maximum effort countermovement jump and ballistic push-up performance were assessed at different timepoints: (1) baseline at the sea level, (2) before training at ∼2100 m, (3) midpoint of training at ∼2100 m, (4) end of training at ∼2100 m, and (5) after 3 to 4 weeks of recovery at the sea level. The fall cohort trained at moderate temperatures (average day/night, 20°C/3°C), whereas the winter cohort trained under snowy winter conditions (7°C/-14°C). The results suggested that seasonal conditions did not significantly affect changes in body composition or physical performance. Furthermore, no acute effects of altitude on physical performance were detected. Training exercise did, however, cause performance decrements in countermovement jump height, countermovement jump peak power, and ballistic push-up height. Repeated measure correlation analyses suggested that there was a weak positive correlation between the decrease in skeletal muscle mass and the decrease in countermovement jump peak power throughout the training. The results of our study suggest that explosive movements are negatively affected by extended military training, seemingly independent of environmental training conditions or temperature. Planning and execution of military training should account for the likelihood that warfighter physical power will decline and may not return to pretraining levels within the month following the training event. It may also be advised to consider targeted exercises to aid in recovery of muscular strength and power. Future work should consider additional factors that likely influenced the decrease in physical performance that occurs during extended military training, such as nutrition, sleep, and psychological and cognitive stresses.

Contingent magnetic variation and beta-band oscillations in sensorimotor temporal decision-making

The ability to accurately encode the temporal information of sensory events and hence to make prompt action is fundamental to humans’ prompt behavioral decision-making. Here we examined the ability of ensemble coding (averaging multiple inter-intervals in a sound sequence) and subsequent immediate reproduction of target duration at half, equal, or double that of the perceived mean interval in a sensorimotor loop. With magnetoencephalography (MEG), we found that the contingent magnetic variation (CMV) in the central scalp varied as a function of the averaging tasks, with a faster rate for buildup amplitudes and shorter peak latencies in the “half” condition as compared to the “double” condition. ERD (event-related desynchronization) -to-ERS (event-related synchronization) latency was shorter in the ”half” condition. A robust beta band (15–23 Hz) power suppression and recovery between the final tone and the action of key pressing was found for time reproduction. The beta modulation depth (i.e., the ERD-to-ERS power difference) was larger in motor areas than in primary auditory areas. Moreover, results of phase slope index (PSI) indicated that beta oscillations in the left supplementary motor area (SMA) led those in the right superior temporal gyrus (STG), showing SMA to STG directionality for the processing of sequential (temporal) auditory interval information. Our findings provide the first evidence to show that CMV and beta oscillations predict the coupling between perception and action in time averaging.

Performance analysis and optimisation of waste heat recovery system based on zeotropic working fluid

As a new type of energy storage technology utilizing thermal energy, the Carnot battery is one of the most promising large-scale energy storage technologies due to its unlimited geographical conditions, simple structure, and high energy storage density. In this work, a thermodynamic model is established for a Carnot battery energy storage system that makes full use of waste heat resources, and the effects of the heat storage temperature, the components and mass fractions of the zeotropic working fluids on the various performances of the system are investigated. The temperature matching of the working fluids with different temperature glides in the heat exchangers are analyzed by using different mass fractions of R1234ze(E)/ R601a in heat pump and organic Rankin cycle systems, and the exergy flow charts and exergy loss of each component in the system are further investigated. The results show that the selection of the zeotropic working fluid with an appropriate temperature glide can effectively improve the system performance by improving the temperature matching degree and reducing the exergy loss in the heat transfer process. Compared with the evaporator, the temperature match of the condenser plays a more important role in the system performance. The use of R1234ze(E)/R601a in the heat pump improves the cofficient of performance by 4.46%-8.98% compared with that of pure R601a when the heat storage temperature increases from 110.0℃ to 140.0℃, and the use of zeotropic working fluid in the organic Rankin cycle also improves the performance by 8.12%-11.58%. For the power recovery of the whole pumped thermal energy storage system, the power-to-power efficiency improvement of the system using R1234ze(E)/R601a is 12.69%-20.11% and that using R1234yf/R601a is 12.46%-17.73% compared with the use of pure R601a. The power-to-power efficiency of R1234ze(E)/R601a (60/40) and R1234ze(E)/R601a (20/80) in the heat pump and organic Rankin cycle, respectively, are as high as 73.93% at a heat storage temperature of 130.0℃, which is 19.75% higher than the 61.74% for pure R601a.

Investigation of degradation dynamics of 265 nm LEDs assisted by EL measurements and numerical simulations

We studied four AlGaN-based 265 nm LEDs with increasing QW thickness (1.4, 3, 6 and 9 nm) during a constant current stress at 100 A cm−2. We focused our attention on the parasitic components of the emission spectra at low current levels and on the optical power recovery observed at high current levels. We associated every parasitic peak or band to a region in the device where they can be generated, also demonstrating if they are related to band-to-band emission or radiative emission through defects. At high current levels, we showed the simultaneous effect of the decrease in injection efficiency in the active region and the increase in non-radiative recombination, by fitting the EQE curves with a mathematical model. Moreover, we associated the optical power recovery with a generation of negative charge near the active region, which led to an increase in injection efficiency in the QW.

Anodic degradation of salicylic acid and simultaneous bio-electricity recovery in microbial fuel cell using waste-banana-peels derived biochar-supported MIL-53(Fe)-metal-organic framework as cathode catalyst

This research was aimed to synthesize waste banana peel biochar (BC) supported MIL-53(Fe) metal–organic framework (MOF) (MIL-53(Fe)/BC) as an efficient cathode catalyst for application in a microbial fuel cell (MFC) for the treatment of salicylic acid (SA)-laden wastewater. This investigation marks the first application of such a catalyst in a MFC for SA degradation. The results revealed an increment in power density of MFC-MIL-53(Fe)/BC by 2.34-folds (142.2 ± 1.5 mW/m2) as compared to MFC-MIL-53(Fe) (60.6 ± 1.8 mW/m2). Removal of chemical oxygen demand in MFC-MIL-53(Fe)/BC (93.8 ± 2.2 %) was found to be comparable to MFC-Pt/C (94.6 ± 1.5 %). The MFC-MIL-53(Fe)/BC demonstrated a 91.5 ± 2.0 % biodegradation of SA. The power recovery per unit cost by MFC-MIL-53(Fe)/BC was found to be 380.21 mW/US$, which is significantly higher than MFC-Pt/C (6.08 mW/US$), indicating that MIL-53(Fe)/BC could be an affordable replacement to pricey Pt as cathode catalyst for efficient oxygen reduction reaction.

Coordinated recovery of interdependent power and water distribution systems

Coordinated recovery of interdependent power and water distribution systems

Lift-Induced Wake Re-Energization for a VAWT-Based Multi-Rotor System

This study explores the performance and near-wake dynamics of a VAWT-based Multi-Rotor System in both its original configuration and in the presence of external lift-generating devices, specifically employed for wake control operations. The wake of a scaled VAWT-based MRS was measured in a wind tunnel using Particle Tracking Velocimetry. Lift-generating devices, including a 3-element cascading wing on top and a single-element wing in the middle of the MRS, were used to enhance wake control and deflection. Measurements in the near-wake revealed notable differences between configurations with and without these devices. Without them, the wake remained concentrated in the actuator surface’s projected downstream area, with minimal crossflow diffusion. Conversely, the configuration with lift-generating devices exhibited significant wake deformation, including axial expansion and lateral contraction, promoting streamwise momentum recovery. As a result, increased power recovery was found downstream of such a system compared to the clean MRS. These findings underscore the potential of such systems, particularly when equipped with lift-generating devices, to manipulate wake dynamics and enhance wind farm efficiency, thereby advancing innovative wind energy solutions.

The role of load and distributed energy resources modeling in voltage recovery studies

Load modeling in power systems is crucial to stability studies. The analysis of certain dynamic phenomena requires proper load modeling. Fault Induced Delayed Voltage Recovery (FIDVR) relates directly to Residential Air Conditioner (RAC) stalling. Therefore, the modeling of induction motor (IM) loads is essential to this analysis. Delayed voltage recovery in the system can result in delayed power recovery in inverters connected to the transmission system, which connects photovoltaic and wind power plants to the Brazilian Interconnected Power System (BIPS). In the last few years, there has been a considerable growth of Distributed Energy Resources (DER) in Brazil. Modern and legacy ride-through settings coexist in power systems around the world. Inverters with legacy settings are more likely to disconnect in systemic events. This creates a context that has been assessed in this paper. The modeling of induction motors in the Acre-Rondonia system leads to a deterioration of this system’s dynamic performance, which can lead to collapse. DER’s voltage support can contribute to post-fault system voltage recovery, mitigating the delay caused by RAC stalling and avoiding collapse. Thus, more robust ride-through settings are required to avoid inverter disconnection. Moreover, dynamic voltage support and reactive current priority requirements are demands from inverters connected to the system. The results obtained show that this consideration enable more consistent results than the ones obtained by the classic ZIP load model.