Reactive Control Research Articles

Impaired Reactive Control But Preserved Proactive Control in Hyperactive Children

Objective: To examine the manifestation of cognitive control deficit of children with different levels of hyperactivity, an “at risk” dimension for ADHD. Method: A group of children with high hyperactivity (N = 40) and another group of children with low levels of hyperactivity (N = 38) performed a modified stop-signal anticipation task, a revised Go/NoGo task, and the AX-continuous performance test (AX-CPT). Results: Children with higher levels of hyperactivity displayed: (1) significantly prolonged stop signal reaction time (SSRT) in the modified stop-signal anticipation task; (2) no notable differences in commission errors in the revised Go/NoGo task; (3) increased reaction time (RT) in stop-signal task and Go/NoGo task with increased probabilities of stop or NoGo signal; and (4) positive proactive behavioral index scores in AX-CPT. Conclusion: The results suggested that children with heightened hyperactivity exhibited impaired reactive control, especially for responses already underway, but preserved proactive control. Further studies concerning these children are warranted.

Novel Synthesis Route of Plasmonic CuS Quantum Dots as Efficient Co-Catalysts to TiO2/Ti for Light-Assisted Water Splitting.

Self-doped CuS nanoparticles (NPs) were successfully synthesized via microwave-assisted polyol process to act as co-catalysts to TiO2 nanofiber (NF)-based photoanodes to achieve higher photocurrents on visible light-assisted water electrolysis. The strategy adopted to perform the copper cation sulfidation in polyol allowed us to overcome the challenges associated with the copper cation reactivity and particle size control. The impregnation of the CuS NPs on TiO2 NFs synthesized via hydrothermal corrosion of a metallic Ti support resulted in composites with increased visible and near-infrared light absorption compared to the pristine support. This allows an improved overall efficiency of water oxidation (and consequently hydrogen generation at the Pt counter electrode) in passive electrolyte (pH = 7) even at 0 V bias. These low-cost and easy-to-achieve composite materials represent a promising alternative to those involving highly toxic co-catalysts.

Coordinated Control of Transient Voltage Support in Doubly Fed Induction Generators

The large-scale integration of wind power significantly alters the voltage dynamic characteristics of power systems. Wind turbines have a weak ability to withstand grid disturbances and have difficulty in providing effective reactive power support during transient periods. The sensitivity of wind turbines to the grid voltage significantly increases the probability of large-scale, cascading off-grid events. This paper proposes a coordinated control strategy to enhance the transient reactive power support capability of doubly fed wind farms. The additional stator current demagnetization control reduces the risk of a crowbar protection action after a fault and ensures that the unit power is controllable. Based on the voltage–reactive power coupling relationship, each unit can produce reactive power according to the voltage–reactive power sensitivity matrix during the transient period. After the reactive power output of the unit reaches the limit, transient active and reactive combined control is further adopted to reduce the active power output of the unit to a certain extent and improve the reactive power support capability. Finally, two cases are built in the PSCAD to verify the effectiveness of the proposed control strategy. The results show that the proposed control strategy can enable the wind farm to output more reactive power to the grid during the transient period, effectively supporting the system voltage during the transient process and avoiding further deterioration of the fault.

GenesisRM: A state-driven approach to resource management for distributed JVM web applications

Reducing resource waste while maintaining end-to-end latency service-level objective (SLO) by simultaneously managing CPU bandwidth, memory allocation, and pod number of web applications running on Java virtual machine (JVM) is challenging. The challenges stem from the complexity of the multi-type resource allocation optimization problem, the high sensitivity of JVM performance to resource scaling actions, and the lack of low-level resource scaling mechanisms. We present GenesisRM, a resource management framework with a novel state-driven architecture. Specifically, we design a state control model for JVM web applications that encompasses seven pod states. This model serves as an abstraction layer, decoupling the centralized resource management system into a global state manager and distributed pod managers. The state manager controls the state transitions of the pods based on the overall workload, while the pod managers dynamically allocate resources for each pod according to the state and local workload.Then, we propose a multi-frequency control model with two predictive state controllers and a reactive state controller to manage the state of pods based on the state control model. In addition, GenesisRM brings new mechanisms to scale JVM pods’ low-level resources without damaging their performance. We evaluate our work using a real-world JVM web application benchmark in three different scale server clusters of Pengcheng Laboratory Developer Cloud, and the 21-day experimental results show that GenesisRM saves 31.70% CPU and 17.60% memory compared to the best-performing state-of-the-art solutions while guaranteeing the SLO imposed on end-to-end latency.

Lower extremity muscle activity during reactive balance differs between adults with chronic traumatic brain injury and controls.

Control of reactive balance is key to achieving safe independent walking and engagement in life activities. After traumatic brain injury (TBI), motor impairments and mobility challenges are persistent sequelae. To date, no studies have explored muscle activity of individuals with chronic TBI during a task that requires reactive control of balance. To investigate lower extremity muscle activity during a reactive balance test performed by adults with chronic severe TBI and matched controls. We hypothesized that abnormal activity of lower extremity muscles would be related with poorer reactive balance performance. Also, we performed an exploratory analysis for those with TBI investigating the impact of unilateral versus bilateral lower extremity involvement in the control of reactive balance. Ten adults with chronic severe TBI who were independent community ambulators and ten matched controls performed the computerized reactive balance test (Propriotest®) while lower extremity muscle activity was recorded. Electromyographic (EMG) activity was contrasted (Mann-Whitney U Test) between groups across each 10 s epoch of the 120 s test. Additionally, test scores were correlated (Spearman) with lower extremity composite EMG activity to distinguish muscle activity patterns related with reactive balance performance. Lastly, reactive balance test scores were correlated with reactive balance test scores and clinical functional measures only for the TBI group. Although the TBI group exhibited greater EMG activity across the entire test compared with the control group, significant differences were not observed. Greater composite EMG activity correlated significantly with poorer reactive balance performance across most of the 10 s windows of the test. Greater muscle activity exhibited during the reactive balance test by individuals with chronic severe TBI compared to those without disabilities, particularly at small unexpected perturbations, highlights the greater physiologic effort required to control reactive balance even after independent ambulation is achieved.

Enhancing fuel breed-burn performance in a sodium-cooled fast reactor using a novel reactivity control method

This study aims to enhance the fuel cycle and fissile breeding performance of a sodium-cooled fast breeder reactor (FBR) by utilizing minor actinides (MAs) as a means of reactivity control alongside partially-inserted control rods. Choosing the PFBR-500 as the reference design, four core models, designated as Cases A, B, C, and D, utilizing various proportions of minor actinides (MAs) were built and simulated using OpenMC. The MA concentrations were optimized to compensate for the withdrawal of control rods and ensure the same initial reactivity for all cores. Burnup analysis over 365 EFPDs revealed a significant increase in cycle length and burnup for the modified cores along with a modest rise in breeding ratio. Notably, Case C, employing 3.45 wt.% MAs in the 88 inner-core fuel subassemblies achieved an extra 62.25 EFPDs cycle length, a 33.74% rise in single-cycle burnup, and a 3.86% increase in breeding gain compared to the reference. Loading MAs into the inner-core region proved to be more effective in enhancing both fertile-to-fissile conversion (thus extending the cycle length and fuel burnup) and transmutation than utilizing MAs throughout the core due to greater neutron flux at the core center. While Case D utilizing 2.2 wt.% MAs both in the inner and outer core fuel subassemblies had the highest overall MA loading, it demonstrated lower increments in cycle length, burnup, and breeding gain compared to Case C. Case C also exhibited the highest overall destruction rate (approximately 24%/y) for Np and Am isotopes, and successfully transmuted around 24.08 kg 237Np, 9.33 kg 241Am and 3.82 kg 243Am over the course of a single year. The addition of MAs also achieved a slight flattening of the axial and radial flux profile and a decrease in the flux peaking factor. However, it slightly lowered the beta-effective, Doppler constant, and control rod assembly worth, and shifted the coolant void reactivity worth to the positive side.

Enhanced Recovery of Lithium and Cobalt from Spent Lithium-Ion Batteries Using Ultrasound-Assisted Deep Eutectic Solvent Leaching

This study investigates the ultrasound-assisted leaching of Li and Co from spent batteries using a deep eutectic solvent (DES) composed of polyethylene glycol and thiourea. The synergistic effect of ultrasound and DESs was explored to enhance the efficiency of Li and Co recovery. The experimental results demonstrated that ultrasound significantly accelerates the leaching process, achieving up to four times higher recovery rates compared to traditional methods. Optimal leaching conditions were identified at a solid-to-liquid ratio of 0.02 g/g, a temperature of 160 °C, and periodic ultrasound exposure. Under these conditions, the leaching efficiency reached 74% for Li and 71% for Co within 24 h. A kinetic analysis revealed that the ultrasound application shifts the rate-limiting step from a mixed control of mass transfer and chemical reactions to predominantly chemical reaction control, reducing the activation energy by approximately 27%.

Effects of Over-Sintering on Cyclic Calcination and Carbonization of Natural Limestone for CO2 Capture

To know the sustainable performance of calcium-based adsorbents is one of the important aspects to realize efficient and economical carbon capture, and to systematically study the properties of natural adsorbents is conducive to their industrialization. The cyclic calcination and carbonation characteristics of a typical natural limestone were investigated using a thermal gravimetric analyzer. Two kinds of over-sintering conditions were selected to emphatically study the cyclic separation of CO2 from limestones through prolonging the calcination time and increasing the calcination temperature. The results showed that the untimely end of the chemical reaction control stage caused by excessive sintering is the direct reason for the reduction in cyclic carbonation conversion, and the changes in surface morphology of calcined products due to pore collapse and fusion are the fundamental reasons for the reduction in cyclic carbonation conversion. The excessive sintering caused by extending the calcining time or increasing the calcining temperature has great inhibition on this cycle only; the inhibition decreases rapidly in subsequent cycles. In addition, SEM and BET–BJH tests further confirm the influence of the over-sintering phenomenon. With the further increase in cycle number, the early excessive sintering has certain stimulative effects on the subsequent carbonation reaction. It is expected to provide a reference for the subsequent research and development of natural calcium-based adsorbents.

Research on reactive power voltage control strategy of distribution network based on information sharing technology

Abstract In view of the fact that the traditional voltage control of the distribution network is suitable for local voltage control and affects the economy of the operation of the distribution network, a reactive power voltage control strategy of the distribution network based on information-sharing technology is proposed. First, the overall architecture of voltage control in the distribution network based on information-sharing technology is analyzed, and secondly, an algorithm based on the Jacobian sensitivity matrix is established with the minimum voltage RMS as the control goal. The model is solved, and finally, the effectiveness of the proposed voltage control strategy is verified by combining actual examples. The results show that the proposed voltage control strategy has a better voltage regulation effect and effectively reduces the overall voltage deviation of the distribution network.

Research on reactive power voltage control strategy of distribution networks containing distributed PV

Abstract With the large-scale increase in photovoltaic power generation, its integration into the grid will affect the system voltage of the distribution network. This paper presents a reactive voltage control strategy for the distribution network based on deep reinforcement learning. Firstly, the objective function model is established based on the node voltage and network loss of the distribution network. Secondly, each photovoltaic inverter is modeled as an agent of the enhanced learning environment. The collaborative control problem of the photovoltaic inverter is transformed into an observable Markov decision-making process through the distribution network partition. The paper uses a double delay depth deterministic gradient algorithm to solve the problem. Finally, combined with the improvement of 33 nodes for verification, the proposed strategy has the stability of improving voltage, presenting an ability to effectively reduce network loss and verify the effectiveness of the proposed strategy.

Connection of social anxiety to impaired pattern of cognitive control and underlying motivational deficiencies: Evidence from event-related potentials.

Numerous studies have established a correlation between social anxiety and poor cognitive control. However, little is known about the cognitive control pattern of individuals with high social anxiety (HSAs) and the underlying mechanisms. Based on the Dual Mechanisms of Control framework and the Expected Value of Control theory, this study explored whether HSAs have an impaired cognitive control pattern (Experiment 1) and whether motivational deficiencies underlie the impaired control pattern (Experiment 2). In Experiment 1, 21 individuals with low social anxiety (LSAs) and 21 HSAs completed an AX-Continuous Performance Task. Results showed that HSAs had a smaller P3b amplitude than LSAs, indicating their weakened proactive control in the cue processing stage, but a larger contingent negative variation (CNV) on cue B as compensation for the negative effects of anxiety in the response preparation stage. No group difference was found in N2 and P3a amplitude on probes, suggesting that reactive control in HSAs was not affected compared to LSAs. In Experiment 2, 21 LSAs and 21 HSAs completed a cued-flanker task, where the likelihood of proactive control engagement was manipulated. The results revealed that HSAs exhibited motivation deficiencies in engaging in proactive control, as evidenced by P3b, CNV amplitude, and response times. These findings shed light on the impaired cognitive control pattern of HSAs and suggest that motivational deficiencies may be the crucial underlying factor.

Research on Reactive Power Optimization of Synchronous Condensers in HVDC Transmission Based on Reactive Power Conversion Factor

With the rapid development of high-voltage direct current (HVDC) transmission systems, the coupling between AC and DC grids is becoming increasingly close. Voltage disturbances in the grid can easily cause commutation failures in the DC system, threatening its safe and stable operation. The new generation of synchronous condensers (SCs) and modified synchronous condenser units are powerful reactive power support devices widely used in large-capacity DC transmission systems. To maximize the voltage support and commutation failure suppression of SCs, this paper proposes improvements in the initial operating state of SCs, using the Shanxi–Wuhan HVDC receiving end in the Hubei power grid as an example, to better support the HVDC commutation process. Additionally, a reactive power output optimization strategy for SCs is proposed, considering the reactive power equivalent factor of electrical connections between grid nodes. This strategy determines the optimal reactive power output limit of SCs near the converter station to suppress DC commutation failures. Simulation results show that this strategy effectively utilizes the dynamic support capabilities of SCs, prevents DC commutation failures, improves HVDC transmission capacity, and enhances the safety and stability of the receiving end power grid, providing theoretical guidance for reactive power output control.

Low-Frequency Oscillations in Mid-rostral Dorsolateral Prefrontal Cortex Support Response Inhibition.

Executive control of movement enables inhibiting impulsive responses critical for successful navigation of the environment. Circuits mediating stop commands involve prefrontal and basal ganglia structures with fMRI evidence demonstrating increased activity during response inhibition in the dorsolateral prefrontal cortex (dlPFC)-often ascribed to maintaining task attentional demands. Using direct intraoperative cortical recordings in male and female human subjects, we investigated oscillatory dynamics along the rostral-caudal axis of dlPFC during a modified Go/No-go task, probing components of both proactive and reactive motor control. We assessed whether cognitive control is topographically organized along this axis and observed that low-frequency power increased prominently in mid-rostral dlPFC when inhibiting and delaying responses. These findings provide evidence for a key role for mid-rostral dlPFC low-frequency oscillations in sculpting motor control.

Assessment of nominal and off-nominal parameters of a soluble boron free small modular reactor design

Boric acid is traditionally used for reactivity control in pressurised water reactors. However, it increases the rate at which reactor components corrode. This leads to increased operational radioactive waste produced through neutron-activation of corrosion fragments. During reactor operation, radioactive corrosion product deposits, or so-called crud, accumulate on fuel cladding in regions of high burnup. Boron compounds have been detected in such deposits, and they cause axial-offset anomaly, i.e. deviation in axial power prediction. Accumulation of boron-laden deposits can reduce plant efficiency to about 70 % over time. This work presents the design process and analysis of nominal and off-nominal parameters of a soluble boron-free small modular reactor core. The design, and analyses were carried out using CASMO4e, CMSLINK, and SIMULATE3 codes. In addition, a borated variant of the target boron-free core was designed and used as reference. Equilibrium cycles were achieved for both the reference and the boron-free core. The limiting FΔH during the transition to equilibrium was found to be 1.754 and 1.651 for the reference and boron-free cores. The equilibrium FΔH were found to be 1.624 and 1.57 compared to the design limit of 1.7. The hot zero power MTC for the boron-free core at beginning of cycle was found to be –22.67 pcm/K compared to −3.64 pcm/K for the reference. The removal of boric acid made the MTC coefficients more negative and the FΔH lower compared to the reference. The boron-free core had enough rod-worth for power and isothermal defect counteraction and reactor shut down.

Dynamic balance and gait impairments in Parkinson's disease: novel cholinergic patterns.

The cholinergic system has been implicated in postural deficits, in particular falls, in Parkinson's disease (PD). Falls and freezing of gait typically occur during dynamic and challenging balance and gait conditions, such as when initiating gait, experiencing postural perturbations, or making turns. However, the precise cholinergic neural substrate underlying dynamic postural and gait changes remains poorly understood. The aim of this study was to investigate whether brain vesicular acetylcholine transporter binding, as measured with [18F]-fluoroethoxybenzovesamicol binding PET, correlates with dynamic gait and balance impairments in 125 patients with PD (mean age 66.89 ± 7.71 years) using the abbreviated balance evaluation systems test total and its four functional domain sub-scores (anticipatory postural control, reactive postural control, dynamic gait, and sensory integration). Whole brain false discovery-corrected (P < 0.05) correlations for total abbreviated balance evaluation systems test scores included the following bilateral or asymmetric hemispheric regions: gyrus rectus, orbitofrontal cortex, anterior part of the dorsomedial prefrontal cortex, dorsolateral prefrontal cortex, cingulum, frontotemporal opercula, insula, fimbria, right temporal pole, mesiotemporal, parietal and visual cortices, caudate nucleus, lateral and medial geniculate bodies, thalamus, lingual gyrus, cerebellar hemisphere lobule VI, left cerebellar crus I, superior cerebellar peduncles, flocculus, and nodulus. No significant correlations were found for the putamen or anteroventral putamen. The four domain-specific sub-scores demonstrated overlapping cholinergic topography in the metathalamus, fimbria, thalamus proper, and prefrontal cortices but also showed distinct topographic variations. For example, reactive postural control functions involved the right flocculus but not the upper brainstem regions. The anterior cingulum associated with reactive postural control whereas the posterior cingulum correlated with anticipatory control. The spatial extent of associated cholinergic system changes were least for dynamic gait and sensory orientation functional domains compared to the anticipatory and reactive postural control functions. We conclude that specific aspects of dynamic balance and gait deficits in PD associate with overlapping but also distinct patterns of cerebral cholinergic system changes in numerous brain regions. Our study also presents novel evidence of cholinergic topography involved in dynamic balance and gait in PD that have not been typically associated with mobility disturbances, such as the right anterior temporal pole, right anterior part of the dorsomedial prefrontal cortex, gyrus rectus, fimbria, lingual gyrus, flocculus, nodulus, and right cerebellar hemisphere lobules VI and left crus I.

Reactor core design with enriched gadolinia burnable absorbers for soluble Boron-Free operation in the innovative SMR

Effective strategies for maintaining reactor reactivity at a consistent level are indispensable to enable soluble boron-free (SBF) operation in innovative small modular reactor (i-SMR) operation. This paper presents a reactor core design tailored for SBF operation in i-SMR, utilizing concentrated gadolinia burnable absorber rods. This investigation evaluates the concentration range of 155,157Gd and its reactivity characteristics, which are crucial for sustaining excess reactivity. The viability of employing enriched 155,157Gd for the i-SMR SBF operation is established through comprehensive analysis and simulations. Moreover, integrating 155,157Gd with integral gadolinia burnable absorber rods enhances the reactivity control and operational adaptability. Leveraging the spatial self-shielding effect of gadolinia extends the reactivity management capabilities and ensures the operational performance of the i-SMR as optimizing the cycle length. Core design considerations encompassing FA configurations and control rod patterns are investigated to ensure safety and performance across the initial and reload cycles. The feasibility of the SBF operation is verified by assessing compliance with the top-tier requirements of the i-SMR, thus underlining its potential for practical implementation.

Phase transformation and roasting kinetics of CIGS waste in air atmosphere

Copper indium gallium diselenide (CIGS) solar cells produce a lot of CIGS waste in the production process. TAK method was used to study the roasting kinetics of CIGS waste to separate and recovery harmful elements of environment. The oxidation of CIGS is different for different heating rates, oxides of various metal elements are formed at lower roasting rates, but InGaCuO4 is formed at higher roasting rates. The E of each oxidation process was obtained by FWO method and KAS method respectively. The E of element In at lower roasting rates are 104.43 KJ/mol and 112.17 KJ/mol. The E of Ga are 105.86 KJ/mol and 113.52 KJ/mol. The E of Cu are 134.46 KJ/mol and 141.35 KJ/mol. The E of InGaCuO4 were 33.45 KJ/mol and 45.53 KJ/mol. The model function of CIGS waste reaction was determined by Malek method analysis. The oxidation mechanism model of element In is No.39 and No.40 functions: Exponential law. The oxidation mechanism model of the element Ga is function No.37: Chemical reaction control, and the oxidation mechanism model of the element Cu is function No.9:3-D diffusion Zhuraalev-Lesokin-Tempelman. The mechanism model of CIGS waste higher roasting rates in second stage is function No.9:3-D diffusion Zhuraalev-Lesokin-Tempelman. The results show that the heating rate of roasting process obviously affects the oxidation behavior of CIGS waste, so it is of great significance to control the heating rate to oxidizes CuO, Ga2O3 and In2O3 in CIGS waste, and to improve the separation and recovery efficiency of elements in the subsequent process.

Center of mass states render multi-joint torques throughout standing balance recovery.

Reactive balance control requires coordination of neurally-mediated feedforward and feedback pathways to generate stabilizing joint torques at the hip, knee, and ankle. Using a sensorimotor response model, we decomposed reactive joint torques into feedforward and feedback contributions based on delays relative to center of mass kinematics. Responses across joints were driven by the same signals, but contributions from feedforward versus feedback pathways differed, likely due to differences in musculotendon properties between proximal and distal muscles.

Study on Column Leaching Behavior of Low-Grade High Calcium and Magnesium Copper Ore

This paper studies the process mineralogy, mechanism, and kinetics of column leaching behavior of low-grade high-calcium–magnesium copper ore. The effect of sulfuric acid concentration, leach solution spraying intensity, and material particle size on column leaching kinetics is discussed. The kinetic analysis of column leaching of copper indicates that sulfuric acid concentration has a significant impact. As sulfuric acid concentration increases, the limiting step of reaction shifts from chemical reaction control to a combination of chemical reaction and diffusion mixing control. Spraying intensity also affects copper column leaching; increasing intensity shifts the limiting step from diffusion control to mixing control, thereby mitigating the effects of diffusion control. Regarding other elements, it is found that iron leaching is primarily controlled by chemical reaction, while calcium leaching is mainly controlled by chemical reaction. As sulfuric acid concentration increases from 10 g/L to 20 g/L, the limiting step for calcium leaching shifts from chemical reaction control to chemical reaction and diffusion-mixing control.

Detection of Axial Locations of Control Rods Using Movable In-core Detectors

Background Reactivity control in Pressurized Water Reactors (PWRs) relies on Rod Cluster Control Assemblies (RCCAs), or control rods (CRs), and boric acid diluted in primary circuit water. The control rods’ axial location inside the reactor core is typically provided by means of two redundant systems: the Rod Positioning Indicator (RPI) and the Rod Control System (RCS). Methods The current work focuses on the development of an additional method for the detection of control rod axial location inside the reactor core of a Pressurized Water Reactor (PWR) using the Advanced Flux Mapping System (AFMS) and its Movable In-core Detectors (MIDS). The paper presents the methodology employed and the results of the first validation campaigns. Results Two validation campaigns were carried out, targeting respectively equilibrium and non-equilibrium xenon axial distribution. The routine proved successful in identifying control rods’ axial insertion in different operating conditions including Flux Maps (FMs) acquired at 2%, 50% and 75% power. Conclusions The routine developed at Beznau Nuclear Power Plant will serve as an additional core monitoring tool to be employed in case of suspicious or faulty indication coming from the main control rod location methods. The developed method proved able to locate control rods’ axial insertion with few steps error, though there is room for potential improvements with regards to the uncertainty model currently implemented.