Changes In Power Research Articles

Frontal and temporo-parietal changes in delta and alpha power accompany stress-induced vasoconstriction and blood pressure response.

Exaggerated blood pressure and vasoconstriction responses during acute mental stress are prospectively associated with an increased risk of hypertension, arrhythmia and vascular dysfunction. This study assessed electrophysiological brain power and cardiovascular response to acute psychological stress during concurrent recordings of magnetoencephalography, muscle sympathetic nerve activity and blood pressure in 29 healthy participants. Brain power was filtered through delta (1-4Hz), theta (4-8Hz), alpha (8-13Hz), beta (13-30Hz), low gamma (30-80Hz) and high gamma (80-120Hz) bands. Stress induced significant increases in systolic blood pressure (SBP), 5.2±5.6 mmHg, heart rate, 4.1±4.8 bpm and sympathetic nerve activity, 4.0±8.0 bursts per minute (mean ± standard deviation, P<05). Whole head and region of interest analyses showed stress induced significant increases in delta power in the right medial frontal cortex, anterior cingulate and amygdala. Alternatively, there were significant decreases in alpha power in the left and right precuneus, posterior cingulate, hippocampus and in the right thalamus and insula. Correlation analyses revealed that reduced alpha power in the right insula was correlated with SBP (r=0.446). Moreover, reduced alpha power in the left amygdala was correlated with SBP (r=0.392), anxiety and depression inventory scores, P<0.01. The reduced alpha power in the insula and amygdala was pronounced in participants displaying heightened sympathetic nerve reactivity to stress. Similarly, participants who displayed higher mean SBP reactivity (of 19 mmHg) to stress showed reduced alpha power in the precuneus, hippocampus and amygdala. Our results suggest that regionalized and frequency specific brain power is involved in neurogenic blood pressure regulation in normotensive individuals.

Real-time monitoring of temperature history of molten pool and corresponding relationship with processing quality in LMD

Purpose The purpose of this study is to investigate the changes in the processing parameters of laser melting deposition (LMD) on the temperature and morphology of the molten pool, and to provide control strategies and basis for further feedback control. Design/methodology/approach This paper is based on LMD equipment and sets up an online monitoring device. The online monitoring device mainly includes an optical camera and a pyrometer. Evaluate the impact of changes in process parameters on the printing process by testing the macroscopic morphology, microstructure and mechanical properties of the samples. Findings The changes in scanning speed mainly cause changes in the depth of the molten pool, without affecting the temperature of molten pool. Meanwhile, the change of laser power has a significant impact on the temperature of molten pool, as well as on the size and depth of molten pool. In addition, the change of temperature and dimensions of the molten pool would affect the temperature gradient and cooling rate, resulting in the difference between the final grain size and the number of equiaxed grains. Subsequently, these factors would affect the tensile properties and plastic toughness of the final formed parts. Originality/value In others’ earlier and the authors’ experiments, they found that changes in scanning rate had little effect on the temperature and surface area of the melt pool, but they did not pay attention to this phenomenon. The authors’ have studied this phenomenon in experiments and provided an explanation.

Parameter Self-Adjusting Single-Mode Fiber Nutation Coupling Algorithm Based on Fuzzy Control

The free-space optical communication fiber coupling system requires improved coupling efficiency through the fiber nutation algorithm. However, traditional fiber nutation algorithms suffer from issues such as fixed parameters and limited correction range. To address these challenges, a parameter self-adjusting single-mode fiber nutation coupling algorithm based on fuzzy control is proposed. Firstly, by leveraging the principles of fuzzy control and analyzing the influence of nutation parameters, a fuzzy controller with power and power change rate as input and nutation parameter as output is designed. Subsequently, we simulate and evaluate the static and dynamic performance of the fuzzy controller. The simulation results indicate that our algorithm outperforms traditional coupling algorithms in terms of coupling efficiency, accuracy, and speed. Finally, experimental results confirm the static and dynamic performance improvements of the parameter self-adjusting single-mode fiber nutation coupling algorithm based on fuzzy control. Specifically, under static conditions, the correction range of the proposed algorithm is approximately five times greater than that of the traditional algorithm. Under dynamic conditions, the disturbance suppression bandwidth increases to 8 Hz, nearly ten times greater than that of the traditional algorithm, significantly enhancing fiber nutation performance.

Sensitivity Analysis of Space Parameters for Integrated Natural Circulation Reactor Under the Rolling Condition Coupling Power Increase

In order to meet the needs of offshore platform reactor design, the flow characteristics of the integrated natural circulation reactor under the rolling condition coupling power increase was analyzed and a typical three-dimensional analysis model of natural circulation was established. Computational fluid dynamics methods were used to numerically simulate natural circulation under swing conditions, and the velocity and temperature distribution characteristics during different power changes were analyzed. The results indicated that there is a more pronounced “overshoot” phenomenon in temperature and flow rate corresponding to the condition of significantly increasing power. The swinging could enhance the internal wall heat transfer flux of the rising heat transfer component. Under conditions of severe oscillation, the descending flow channel has a significant reheating effect on the cold fluid at the outlet of the heat exchanger. For different oscillation cycle conditions, the temperature changing process during the transient process is smoother under the condition of significantly increased power.

Study on nonlinear vibration characteristics of elastic web herringbone gear transmission

In the advanced helicopter gear transmission system, the elastic web gear structure is a new type of vibration reduction structure. Its vibration reduction mechanism, parameter value and control strategy are all scientific problems to be solved urgently. This paper establishes the nonlinear dynamic equation of elastic web herringbone gear transmission system under multi-factor coupling. The influence of four potentially applicable elastic materials on the system dynamic load sharing performance is explored. Then the effects of these two materials on the system nonlinear vibration characteristics under different working conditions are analyzed. Finally, the variation of dynamic load coefficient (DLC) and load sharing coefficient (LSC) with input/output torque excitation and system structure size under the action of two materials is analyzed. The results show that compared with elastic web without consideration, when the web is made of beryllium copper, Ni40Cr20Co20Mo, spring steel and silicon rubber, the DLCs of the left and right sides of gear pair are different by 21.68%, 7.64%, 21.55% and 3.5%, so the load sharing performance of silicon rubber is better. When the input speed changes, when the silicone rubber is used than the superalloy, the periodic motion area of the system is relatively large, which is beneficial to improve the system stability. With the change of input power, silicone rubber is more beneficial to periodic motion than superalloy. The research results can guide the design, optimization and control of the new generation of helicopter and ship elastic web gear system.

Maximum Power Point Tracking Technology for Offshore Floating PV Based on Model Predictive Control

A Perturb and Observation (P&amp;O) algorithm is proposed to track the maximum power point of offshore photovoltaic power generation by disturbing the output voltage (or current) of the photovoltaic cell in this paper, and then observing the change of the output power of the photovoltaic cell, and continuously changing the direction of the disturbed voltage (or current) according to the trend of power change, so that the photovoltaic cell finally works at the maximum power point. Combined with wave fluctuation characteristics and model predictive control (mpc), the photovoltaic power generation output is predicted in the future time period, and the output of thermal power units is adjusted accordingly. The realization of maximum power point tracking and photovoltaic power generation prediction can adapt to the traditional thermal power units can not quickly track power, and solve the problem of large-scale light abandonment and offshore consumption to a certain extent.

A humidity sensor utilizing multimode interference coreless silica fiber

Abstract Functional film-based humidity optical fiber sensors often face issues such as complexity, high cost, coating degradation, and dependence on uniform coatings, affecting their reliability. This research presents a coating-free relative humidity (RH) sensor using coreless silica fiber (CSF) in an SMF-CSF-SMF multimode interference (MMI) structure. Humidity changes alter the effective refractive index around the CSF, shifting the interference pattern in the C-band. Simulations modeled RH by varying the surrounding refractive index from 1.000 (0% RH) to 1.333 (100% RH), yielding a sensitivity of 1.319 × 10⁻⁹ RIU with strong linearity (R² = 0.9468). Sensitivity increased with reduced CSF diameter, and optimal performance was achieved at the 4th self-image length. Experiments using 125 µm CSF showed the 4th self-image sensor had the highest sensitivity, with a 1 dB power change from 50% to 100% RH. This CSF-based sensor is simple, temperature-insensitive, and reliable without using functional films.

A Novel Integrated Energy Management Strategy of Energy Storage System for a Pure Electric-Driven Mining Hydraulic Excavator

Using electric motors instead of diesel engines as the driving system for mining excavators can reduce the energy consumption and operating costs. However, pure electric-driven mining excavators are prone to unexpected power outages in mines because of drastic changes in load power, leading to significant fluctuations in the power demand of the grid, which in turn affects production. To solve the above problem, a pure electric-driven mining hydraulic excavator based on electric-motor-driven swing platform and hydraulic pumps was used as the research object. Moreover, supercapacitors and DC/DC converter, as the energy storage system (ESS) adjust the output power of the grid and recover the braking kinetic energy of the swing platform. Subsequently, a novel integrated energy management strategy for a DC bus voltage predictive controller based on the power feedforward of fuzzy rules is proposed to run mining excavators efficiently and reliably. Specifically, the working modes of the ESS are determined by the DC bus voltage and state of charge (SOC) of the supercapacitor. Next, the output power of the supercapacitor and the DC bus voltage were controlled by adjusting the charging and discharging currents of the DC/DC converter using a predictive controller and fuzzy rules. In addition, a digital prototype of the excavator was verified using an original machine test. The performance of the different strategies and driven systems were analyzed using digital prototypes. The results showed that, compared with traditional excavators with diesel engines, the operational cost of the developed excavators was reduced by 54.02%. Compared to pure electric-driven excavators without an ESS, the peak power of the grid for the developed excavators was reduced by 10%. This study designed an integrated energy management strategy for a pure electric mining excavator that can regulate the power output of the grid and maintain the stability of the bus voltage and SOC of the ESS.

Cortical signatures linked to behavior quantitatively track arousal levels

While current arousal level assessments in patients with disorders of consciousness discriminate altered states of consciousness, there are significant limitations in characterizing the transition from one state to another or quantifying the frequent arousal level fluctuations observed in a patient. Here, we identified a repeated, temporally discrete, dynamical pattern evident in the recovery of consciousness from anesthesia and brain injury coma models in rodents. We prospectively validated these features we label "Arousal Units" (AU) in neonatal humans recovering from static hypoxic injuries and senior patients emerging from anesthesia indicating their generalizability. The AUs lawfully link changes in spectral power and breathing frequency and reliably associate with motor changes. Distinctive cortical patterns within AUs can be transformed into arousal indices, determining arousal levels. The reliability of these events is demonstrated across intact and brain-injured states and translates to the human brain; extracting these stereotyped dynamics could aid anesthesia monitoring, tracking coma recovery, and identifying cognitive motor dissociation.

Identifying EEG markers related to acute cannabis consumption: A systematic review.

Identifying EEG markers related to acute cannabis consumption: A systematic review.

Individual differences in resting alpha band power and changes in theta band power during sustained pain are correlated with the pain-relieving efficacy of alpha HD-tACS on SM1.

Individual differences in resting alpha band power and changes in theta band power during sustained pain are correlated with the pain-relieving efficacy of alpha HD-tACS on SM1.

Spinal and corticospinal excitability changes with voluntary modulation of motor cortex oscillations.

Spinal and corticospinal excitability changes with voluntary modulation of motor cortex oscillations.

Trait anxiety negatively modulates the coupling of motor event-related desynchronization and event-related synchronization

BackgroundRecent neurophysiological studies showed that patients with psychiatric disorders demonstrated abnormalities in sensorimotor functions in addition to cognitive deficits. These findings intrigued us to investigate whether trait anxiety, a persistent inclination towards being anxious in multiple contexts, would affect motor cortical functions. Event-related desynchronization (ERD) and event-related synchronization (ERS) of α and β oscillations are associated with movement execution and movement termination, respectively. However, no study has comprehensively examined the effects of trait anxiety on motor ERD and ERS. Therefore, this study aimed to determine how trait anxiety influences these motor cortical oscillations.MethodsTwenty subjects (top 10% of the trait anxiety score distribution from 400 college students) with higher trait anxiety (HTA) and 20 subjects (bottom 10% of trait anxiety score distribution from the same sample) with lower trait anxiety (LTA) were recruited to perform a Go-Nogo task during electroencephalographic recordings. ERD and ERS of α and β oscillations to Go responses were compared between these two groups. The associations between ERD and ERS in each group were also examined.ResultsNeither ERD nor ERS power changes were significantly different between LTA and HTA groups. Interestingly, a significant correlation between β ERD and α ERS/β ERS was found in the individuals with LTA; however, such functional coupling was not present in the individuals with HTA.ConclusionTrait anxiety negatively modulates the coupling of motor ERD and ERS.

Effects of fatty acids with different degrees of saturation on the microwave freeze-drying characteristics and cross-linking behavior of wheat starch-fatty acid complexes.

Effects of fatty acids with different degrees of saturation on the microwave freeze-drying characteristics and cross-linking behavior of wheat starch-fatty acid complexes.

Age-Related changes in joint power during gait: Adaptations in middle-aged adults to maintain walking speed.

Age-Related changes in joint power during gait: Adaptations in middle-aged adults to maintain walking speed.

294. Daily Changes in High-Density EEG Alpha Power and Functional Connectivity Across Five Consecutive Days of 10Hz Transcranial Alternating Current Stimulation in Depression: Results From a Randomized Controlled Trial

294. Daily Changes in High-Density EEG Alpha Power and Functional Connectivity Across Five Consecutive Days of 10Hz Transcranial Alternating Current Stimulation in Depression: Results From a Randomized Controlled Trial

Photovoice: A Promising Method for Capturing and Responding to Climate Change?

ABSTRACTPhotovoice is a popular participatory research method for instigating critical reflection and social change. It does, however, rely on participants being able to photographically capture the phenomenon under study. This raises challenging questions that may obstruct the use of Photovoice in climate change studies. Is climate change visible? Can it be photographically captured? What change can Photovoice instigate in the context of global climate change? To gain clarity on the role of Photovoice in climate change studies, this article provides an overview of previously published work. We do this to identify some of the different ways in which Photovoice can usefully capture various aspects of climate change and to critically appraise the studies' ability to fully leverage Photovoice's change potentials. We identify five ways in which Photovoice is used to study climate change. This includes studying (i) how local people understand climate change, (ii) how people experience the (perceived) impacts of climate change, (iii) community perspectives on their vulnerabilities to climate change, (iv) local adaptation and mitigation responses, and finally, (v) ways of facilitating transformative learning about climate change. While many studies effectively capture people's intersubjective relationships with climate change, the action‐oriented social change potential of Photovoice is rarely realized. Future Photovoice projects must consider the theoretical underpinnings of the method and be intentional about its emancipatory and change potential, particularly by collaborating with powerful change agents, thereby increasing the likelihood that Photovoice findings will translate into policy changes and community initiatives.

Facilitating cognitive neuroscience research with 80-sensor optically pumped magnetometer magnetoencephalography (OPM-MEG).

Facilitating cognitive neuroscience research with 80-sensor optically pumped magnetometer magnetoencephalography (OPM-MEG).

Gastric Myoelectrical Activity Subtypes in Functional Dyspepsia and Gastroparesis.

Gastric dysrhythmias, loss of normal 3 cycles per minute (CPM) gastric myoelectrical activity (GMA), and variable loss of interstitial cells of Cajal are reported both in gastroparesis (GP) and functional dyspepsia (FD). We hypothesize that the patients with GP, and FD with normal gastric emptying (NGE) and delayed gastric emptying (DGE) may vary in symptom severity, and GMA profiles. Symptoms and their severity were evaluated by gastroparesis cardinal symptom index (GCSI), Abell scoring, short-form Nepean dyspepsia index (SF-NDI), the World Health Organization quality of life, and Rome IV subtyping for FD. Solid-meal gastric emptying was assessed by nuclear scintigraphy. Water load satiety test (WLST)-based electrogastrography determined GMA. Patients with GP (n = 40) had higher GCSI than those with FD (n = 39; [12 DGE, 27 NGE] (2.79 [2.17-3.33] vs 1.67 [0.83-2.61] vs 0.83 [0.55-1.93]; P < 0.001, in GP vs FD-NGE vs FD-DGE, respectively), severe Abell grade (Grade III in 17 [43%] vs 0% vs 0%, in GP vs FD-NGE vs FD-DGE, respectively), severe SF-NDI (80.5 [63.5-102.5] vs 50 [27-91] vs 30 [21.25-45.5]); and poor QOL. Sixteen (40%) GP had impaired gastric accommodation (< 238 mL). Post-WLST 3 CPM normal/hypernormal GMA was observed in 17 (42%), 18 (67%), and 5 (42%) patients with GP, FD (NGE), and FD (DGE), respectively; and 3 CPM hyponormal in remaining patients in each group. Post-WLST dysrhythmia was comparable. WLST-electrogastrography coupled with GE study may distinguish between normal/dysrhythmic GMA revealing pathophysiologicalphenotypes of GP and FD. Analysing extent of power change in normogastric, and dysrhythmic frequencies may comprehensively elucidate disease severity.

Scheitelbrechwertprofile weicher rotationssymmetrischer Kontaktlinsen in Abhängigkeit des Aperturdurchmessers

Purpose. The aim of the study was to measure and to compare the power profiles of market-leading single vision and multifocal soft contact lenses. Material and Methods. A high-resolution instrument based on the phase-shifting schlieren method (NIMO TR1504, Lambda-X, Belgium) was used to measure the optical power distribution of single vision and multifocal contact lenses with −3.00 D, −6.00 D, −9.00 D and +3.00 D. The optical power of the single vision lenses was measured at six different aperture diameters ranging from 2.0 mm to 7.0 mm in steps of 1.0 mm. Each multifocal design was measured with an aperture of 7.0 mm. A total of 200 contact lenses was measured, five lenses per power and type. Results. All single vision contact lenses with negative back vertex power showed a negative increase in lens power with increased distance from centre. The changes in power between the central and peripheral aperture were statistically and clinically significant for every negative refractive power and type (p &lt; 0.05). Etafilcon A showed the highest negative increase with greater apertures with values up to 1.19 ± 0.04 D. Lotrafilcon A showed overall the least deviation with maximum values of 0.61 ± 0.05 D. Each type of multifocal contact lens exhibited different power profiles. The profiles were very consistent across all negative back vertex powers. Conclusion. As expected, the negative single vision contact lenses exhibited an increase in lens power towards the periphery due to spherical aberration. Greater aberration resulted in a higher negative deviation. The analysis of power profiles of multifocal lenses provides valuable information for fitting lenses for presbyopes considering their pupil size.