Changes In Power Output Research Articles

Build and Implement Radiation Control using IoT in Parabolic Trough Solar Collector (PTSC)

Connecting the devices to the internet based on the internet of things IoT increases the capability of monitoring and measuring, and controlling essential variables. In this study, the radiation intensity was controlled via the internet of things IoT for PTSC to study the collector's behavior. The light control circuit was designed, built, and implemented. The circuit mainly consists of a power supply, Arduino, relay, and potentiometer. Radiation was successfully monitored using a sensor and displayed through a smartphone via Wi-Fi, and the intensity of radiation light controls the PCM status. A data logging system was applied using a micro SD in a smartphone card and Arduino Node-MCU as a microcontroller. The experimental results show the relationship between solar radiation and resistance change. Inversely, the maximum radiation found from this work was 780 W/m2 with 74 k Ω resistance, and the minimum radiation was 300 W/m2 with 170 k Ω resistance. The output power changes directly through solar radiation, which means the power output with maximum solar radiation will be 3018 W. Using IoT Technology reduces efforts of long-time monitoring during the experiment (many hours).

PLC-Based Integrated Refractive Index Sensor Probe with Partially Exposed Waveguide

This paper proposes a simple, high-efficiency refractive index (RI) sensor, with a structure based on the planar lightwave circuit (PLC) probe type. The optical sensor has a 1 × 2 splitter structure with reference and sensing channels, each consisting of a U-shaped waveguide structure that is configured by connecting C bends. This design allows for the sensor device to have a probe structure wherein the surface interconnected with activity devices (i.e., an optical source and optical detector) is placed on one side. The reference channel is bent with a minimum optical loss, and the sensing channel has a bent structure, involving a C-bend waveguide with a maximum loss. The C-bend waveguide with a maximum loss is conformally aligned to have a trench structure with the same bending radius, designed to selectively expose the sidewall of the core layer. The local index contrast varies depending on the material in contact with the trench, resulting in a change in the optical output power of the waveguide. The sensitivity of the proposed sensor was 0 and 2070 μW/refractive index unit (RIU) for the reference and sensing channels, respectively, as the RI changed from 1.385 to 1.445 at a 1550 nm wavelength. These results suggest that the proposed structure enables efficient RI measurement through the use of a simple dip-type method.

Is the maximal lactate steadystate concept really relevant to predict endurance performance?

There is no convincing evidence for the idea that a high power output at the maximal lactate steady state (PO_MLSS) and a high fraction of [Formula: see text]O2max at MLSS (%[Formula: see text]O2_MLSS) are decisive for endurance performance. We tested the hypotheses that (1) %[Formula: see text]O2_MLSS is positively correlated with the ability to sustain a high fraction of [Formula: see text]O2max for a given competition duration (%[Formula: see text]O2_TT); (2) %[Formula: see text]O2_MLSS improves the prediction of the average power output of a time trial (PO_TT) in addition to [Formula: see text]O2max and gross efficiency (GE); (3) PO_MLSS improves the prediction of PO_TT in addition to [Formula: see text]O2max and GE. Twenty-one recreationally active participants performed stepwise incremental tests on the first and final testing day to measure GE and check for potential test-related training effects in terms of changes in the minimal lactate equivalent power output (∆PO_LEmin), 30-min constant load tests to determine MLSS, a ramp test and verification bout for [Formula: see text]O2max, and 20-min time trials for %[Formula: see text]O2_TT and PO_TT. Hypothesis 1 was tested via bivariate and partial correlations between %[Formula: see text]O2_MLSS and %[Formula: see text]O2_TT. Multiple regression models with [Formula: see text]O2max, GE, ∆PO_LEmin, and %[Formula: see text]O2_MLSS (Hypothesis 2) or PO_MLSS instead of %[Formula: see text]O2_MLSS (Hypothesis 3), respectively, as predictors, and PO_TT as the dependent variable were used to test the hypotheses. %[Formula: see text]O2_MLSS was not correlated with %[Formula: see text]O2_TT (r = 0.17, p = 0.583). Neither %[Formula: see text]O2_MLSS (p = 0.424) nor PO_MLSS (p = 0.208) did improve the prediction of PO_TT in addition to [Formula: see text]O2max and GE. These results challenge the assumption that PO_MLSS or %[Formula: see text]O2_MLSS are independent predictors of supra-MLSS PO_TT and %[Formula: see text]O2_TT.

Numerical Study on the Yaw Control for Two Wind Turbines under Different Spacings

In this study, the large eddy simulation method and the actuator line model are used to investigate the wake redirection of two turbines. Different turbine spacings and yaw-based control of the upstream turbine are considered. The effects of yaw angle and turbine spacing on the output power of two turbines are comprehensively analyzed, and the physical mechanisms of the wake deficit, deflection and interaction are revealed from the distributions of the wake velocity, turbulence intensity and the structures of wake vortices. The results show that the overall power of two turbines is related to the yaw angle of the upstream turbine and the spacing between two turbines. We find yaw angle is the dominant factor in the total power improvement compared to turbine spacing. Still, a large yaw angle causes significant power fluctuations of the downstream turbine. The deficit of wake velocity and the change of output power are determined by the characteristics of the wake flow field, which the yaw control regulates.

Improved perturb and observe maximum power point tracking technique for solar photovoltaic power generation systems

The primary concerns in the practical photovoltaic (PV) system are the power reduction due to the change in operating conditions, such as the temperature or irradiance, the high computation burden due to the modern maximum power point tracking (MPPT) mechanisms, and to maximize the PV array output during the rapid change in weather conditions. The conventional perturb and observe (P&O) technique is preferred in most of the PV systems. Nevertheless, it undergoes false tracking of maximum power point (MPP) during the rapid change in solar insolation due to the wrong decision in the duty cycle. To avoid the computational burden and drift effect, this article presents a simple and enhanced P&O MPPT technique. The proposed technique is enhanced by including the change in current (dI), in addition to the changes in output voltage and output power of the PV module. The effect of including the dI profile with the traditional method is explained with the fixed and variable step-size methods. The mathematical expression for the drift-free condition is derived. The traditional boost converter is considered for validating the effectiveness of the proposed methods by employing the direct duty cycle technique.

The Impact of the Pandemic COVID 19 on Adolescent’s Sports Performance in Czech Republic

Background: During the COVID-19 pandemic, free movement, leisure activities and sports, both competitive and elite, were restricted by measures against the spread of the infection. The study aimed to evaluate the impact of the restricttions on the performance of Czech adolescent competitive athletes. Methods: The sample of the retrospective study comprised 125 participants (41 girls, 84 boys). The initial examination, the mean age of the entire sample was 15.5 ± 1.2 (median 16.0) years; 16.0 ± 1.2 in girls and 15.5 ± 1.2 in boys, respectively. All participants were examined during regular preventive sports health checks from September to November 2019 and a year later. The examination consisted of a complete medical history and physical examination, anthropometric measurements (height, weight and body mass index [BMI] calculations) and maximal exercise testing on a leg cycle ergometer, ECG and blood pressure recordings. The response variables in regression models were power output (W/kg) and MET. Results: In the entire sample, as well as in the boy and girl subgroups, body height, weight, BMI, BMI percentile and power output were significantly increased in 2020 compared to 2019, yet with a statistically significant reduction in both power output per kilogram of body weight and metabolic equivalent (MET). In 2020, the relative power output dropped by 0.13 W/kg and MET by 0.6. There was no statistically significant predictor of changes in relative power output and MET identified in regression models, including no significant impact of the sport type. There were no significant differences in results between genders. Conclusions: Performance and anthropometric parameters, specifically power output per kilogram of body weight and MET, worsened in the sample of adolescent male and female athletes.

A Grid Inductance Detection Method Based on the Oscillation Characteristic of Inverter Terminal Voltage

In grid-connected photovoltaic (PV) systems, grid inductance greatly influences the performance of grid-connected inverters. However, the grid inductance usually varies with the changes of the grid operation conditions. Therefore, accurate grid inductance detection is one of the key technologies to achieve an adaptive control of the grid-connected inverters under different operation conditions. In this article, an equivalent circuit model of a grid-connected PV system which includes the controller, filter, and grid impedance is established. The oscillation characteristic of the inverter terminal voltage caused by the sudden change of the inverter output power is analyzed. The oscillation mechanism of the inverter terminal voltage caused by the interaction of the controller, filter, and grid impedance is investigated. A grid inductance detection method based on the oscillation characteristic of the inverter terminal voltage is proposed. The main advantage of the proposed method is that it does not need complicated signal processing and calculation procedures. A 10-kW grid-connected PV system was built for both simulations and the experimental setup. Finally, simulation and experimental results validate the correctness and effectiveness of the proposed method.

An intelligent hybrid technique for optimal generator rescheduling for congestion management in a deregulated power market

Congestion not only affects the power flow, but also leads certain issues, like market power, market inefficiency and security. When the transmission line exceeds their limits congestion is occurred (voltage, thermal, stability). Congestion management is a technique that helps to deal the issue corresponding to congestion. Many methods have been developed to manage congestion, and also several countries execute various strategies for the smooth functioning of their network. In this manuscript, the rescheduling of congestion management in a deregulated environment using DA-MRFO is proposed. The proposed hybrid technique is the combined execution of both the dragonfly algorithm (DA) and manta ray foraging optimization (MRFO). Dragonfly algorithm is enhanced using Manta ray Foraging optimization (MRFO), hence it is named DA-MRFO technique. The proposed method is used to alleviate transmission grid congestion on group-based electricity market via reprogramming active power of generators and also to reprogram the generator power. Congestion is the major Independent System Operator (ISO) concern on deregulated electricity market that is traditionally controlled by reprogramming generator output power. However, the effects of changes in the generator output power on the overloaded line flow are not identical. All the generators do not represent a desirable approach for congestion management. Here, a generator sensitivity factor is adapted for supporting the optimal generator selection in a congestion management (CM). In a congestion relief process, it is provided at the lowest possible cost. The reduction of power flow with collection of congested lines is probable through coordinated response of reactive energy dispatch as wind farms. The proposed approach is executed in modified IEEE 30 bus system and IEEE 57 bus system, then the efficiency is compared with the various existing optimization approaches.

Fault-Tolerant Capability Analysis of Six-Phase Induction Motor with Distributed, Concentrated and Pseudo-Concentrated Windings

Six-phase motors are becoming more popular because of their advantages such as lower torque ripple, better power distribution per phase, higher efficiency, and fault-tolerant capability compared to the three-phase ones. This paper presents the fault-tolerant capability analysis of a symmetrical six-phase induction motor equipped with distributed, conventional concentrated, and pseudo-concentrated windings under open-circuit fault scenarios. For further investigation, different load types such as constant-speed, constant-torque, and constant-power are applied to the motor. Two concepts of magnetic and physical phase separations are introduced as factors affecting the motor reliability. Analytically, these factors give an insight into how the pseudo-concentrated winding could be a fault-tolerant alternative. Moreover, five parameters such as the change of output power, power loss, power factor, efficiency, and expected load loss are considered as the fault-tolerant capability parameters to evaluate the windings reliability. The aforementioned parameters are reported using the finite element analysis for different fault scenarios and different load types. Although the baseline motor dimensions are not optimized for applying the pseudo-concentrated winding, the pseudo-concentrated shows a promising performance with high fault-tolerant capability.

Parameter Evaluation in Motion Estimation for Forecasting Multiple Photovoltaic Power Generation

The power-generation capacity of grid-connected photovoltaic (PV) power systems is increasing. As output power forecasting is required by electricity market participants and utility operators for the stable operation of power systems, several methods have been proposed using physical and statistical approaches for various time ranges. A short-term (30 min ahead) forecasting method had been proposed previously for multiple PV systems using motion estimation. This method forecasts the short time ahead PV power generation by estimating the motion between two geographical images of the distributed PV power systems. In this method, the parameter λ, which relates the smoothness of the resulting motion vector field and affects the accuracy of the forecasting, is important. This study focuses on the parameter λ and evaluates the effect of changing this parameter on forecasting accuracy. In the periods with drastic power output changes, the forecasting was conducted on 101 PV systems. The results indicate that the absolute mean error of the proposed method with the best parameter is 10.3%, whereas that of the persistence forecasting method is 23.7%. Therefore, the proposed method is effective in forecasting periods when PV output changes drastically within a short time interval.

Does Intra-Aortic Balloon pump (IABP) improve hemodynamics in Asian Indian patients with Acute Coronary Syndrome with cardiogenic Shock? (DIASTASIS study)

Introduction: Intra-aortic balloon pump (IABP) is widely used as a mechanical support device. Current evidence after the IABP-SHOCK II trial is ambiguous. We evaluated the impact of IABP on hemodynamic parameters (Cardiac Output (CO), Cardiac Power Output (CPO) and Systemic Vascular Resistance (SVR)) measured at 6 and 24 hours in patients presenting with cardiogenic shock (CS) with Acute Coronary Syndrome (ACS) amongst Asian Indians. Methods: The efficacy of IABP was evaluated in patients presenting with CS in open-label, prospective, randomized (for randomization every alternate patient presented to an emergency was given IABP support), consecutive 60 patients in ACS with CS with group A (N=30) comprising of those with IABP and Group B without IABP (n=30). Results: Both the groups were matched for baseline characteristics. The revascularization rate was 85% and only the culprit vessel was addressed during the study. Total 9 (15%) patients were managed medically and did not undergo revascularization. The mean changes in Systemic vascular resistance (SVR), cardiac output (CO) and cardiac power output (CPO) after 24 hours in patients with and without IABP showed no statistical difference except for the lower mean dose use of dobutamine in Group A (with IABP) vs Group B (without IABP) (4.08 (1.41) vs. 7.92 (2.52) mcg/kg/min, p<0.0001). Conclusion: The use of IABP in Asian Indians with CS in ACS did not provide any improvement in hemodynamic parameters.

Fully Integrated, 80 GHz Bandwidth, 1.3μ m InAs/InGaAs CW-PW Quantum Dot Passively Colliding-Pulse Mode-Locked (CPM) Lasers for IR Sensing Application

Integrated quantum dot passively mode-locked lasers: IQDMLLs open opportunities for IR sensing. Therefore, here, we investigated structure of quantum dot passively mode-locked lasers (QDMLLs) with colliding-pulse mode-locked (CPM) method in order to reinforce the performance of QDMLLs for ultrahigh-bit-rate compared to self-colliding pulse mode-locking (SCPM) method. The proposed structure is numerically based on finite difference traveling wave (FDTW) method. By considering bias current of 80 mA, which is the bias applied to the gain section, the laser is at its maximum output power. Finally, by comparing the QDMLLs with self-colliding pulse mode-locking (SCPM) method, it is shown that due to the grating caused by the collision of the two counter-propagating pulses in the saturable absorber, the laser bit rate in the structure of CPM is twice the bit rate in structure of SCPM somehow bit rate from 40 GHz in SCPM method increased to 80 GHz in CPM method. Also, grating coupling factor (GCF) changes due to the proposed structure has been shown, so that in the range of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1cm^{ - 1} \le \kappa \le 5cm^{ - 1}$ </tex-math></inline-formula> the laser output power is pulsed wave (PW), while after this range the laser output power changes from a pulsed regime to a continuous wave (CW) regime.

Deep learning to predict power output from respiratory inductive plethysmography data

AbstractPower output is one of the most accurate methods for measuring exercise intensity during outdoor endurance sports, since it records the actual effect of the work performed by the muscles over time. However, power meters are expensive and are limited to activity forms where it is possible to embed sensors in the propulsion system such as in cycling. We investigate using breathing to estimate power output during exercise, in order to create a portable method for tracking physical effort that is universally applicable in many activity forms. Breathing can be quantified through respiratory inductive plethysmography (RIP), which entails recording the movement of the rib cage and abdomen caused by breathing, and it enables us to have a portable, non‐invasive device for measuring breathing. RIP signals, heart rate and power output were recorded during a N‐of‐1 study of a person performing a set of workouts on a stationary bike. The recorded data were used to build predictive models through deep learning algorithms. A convolutional neural network (CNN) trained on features derived from RIP signals and heart rate obtained a mean absolute percentage error (MAPE) of 0.20 (ie, 20% average error). The model showed promising capability of estimating correct power levels and reactivity to changes in power output, but the accuracy is significantly lower than that of cycling power meters.

Visible-light-driven molecularly imprinted self-powered sensor for atrazine with high sensitivity and selectivity by separating photoanode from recognition element

Atrazine (ATZ) is one of the most widely used and highly toxic triazine herbicides in the world. It is of vital significance to realize ATZ detection with high sensitivity, high selectivity and easy on-site feasibility. Herein, assembled with Ti-Fe-O nanotubes (NTs)/Ni(OH)2 photoanode and molecularly imprinted polymer (MIP) functionalized cathode, a novel molecularly imprinted self-powered sensor (SPS) based on visible-light-driven photo fuel cell (PFC) is developed for ATZ. The MIP cathode serves as the recognition element with advantages of low production cost, high mechanical strength and good stability, while the enzyme-free photoanode has excellent visible light activity and particularly catalytic effects on glucose, leading to spontaneously electron generation and driving the whole cell. By using [Fe(CN)6]3− as the electron transfer switch probe, the SPS can sense ATZ rapidly by the change of output power once ATZ is captured by the cathode. Based on the strategy of using typical photoanode with outstanding oxidative catalytic ability for fuel and placing the recognition element on the cathode separately, the proposed SPS demonstrates excellent power generation performance with a maximum open circuit potential (EOCV) of 0.79 V and a maximum output power density (Pmax) of 13.5 μW·cm−2. It shows a wide linear range of 0.002–21.6 ng·mL−1, a low detection limit of 0.61 pg·mL−1, and a prominent selectivity towards ATZ even in the presence of 100-fold interferents. A proof-of-concept for the integration of molecularly imprinted techniques with PFC and the innovative inspiration for wide used of SPS in complicated environmental system has therefore been provided.

Analyzing Tidal Energy Scheme with Variable Inputs that are affected by Tides

Architecture of a tidal power station using a permanent magnet synchronous generator (PMSG) with a Maximum Power Point Tracking Algorithm and a grid-connected final output. The goal of this paper is to increase the power of a tidal power plant by using the MPPT algorithm, that is more accurate and consistent than the escalation automated system. It is required to boost the voltage and amperage accessible on the line to make the system more efficient in managing direct current loads on site after switching to three-phase alternating current. Expand the research to adapt the algorithm to adjustments in the tide and, as a result, changes in the conversion system's output power.

Design, simulation of XOR / XNOR and AND logic gates using the optical two-circle switch

In this paper, first, the optical two-circle switch (OTCS) and then, the XOR / XNOR and AND logic gates were designed, simulated, and optimized. The OTCS designed structure consisted of two rectangular waveguides and two optical circles between them. The light enters from one waveguide, and due to the coupling between the waveguide and the ring, it enters the circle in case of constructive interference, transmitted to the adjacent circle, and finally, transferred to another waveguide. If it is possible to change the properties of the circle in such a way that there is no constructive interference in it, the coupling of the light from the first waveguide to the circle will not occur, therefore the light will come out from the other side of the first waveguide. The continuity condition of electromagnetic fields at the boundary between rectangular and ring waveguides and the scattering condition has been used in all simulation boundaries to simulate this structure. By optimizing the size and type of material in the core and cladding the waveguides and circles, up to 90 percent of input waves were observed from the output of the second waveguide with the barium titanate core. This occurs as a result of coupling modes between waveguides and circles. In the second step, by applying transverse voltage and changing the refractive index, the conditions of constructive interference in the ring were eliminated, and the coupling between the rectangular waveguide and the circle did not occur. As a result, up to 85 percent of the light exited from the end of the first rectangular waveguide. This change of output power from the first to the second waveguide and vice versa can transform the designed structure into a two-state voltage-controlled optical switch; by putting two of these switches together in a row, optical logic gates of XOR / XNOR and AND are simulated and then optimized.

Misalignment Insensitive Wireless Power Transfer System Using a Hybrid Transmitter for Autonomous Underwater Vehicles

Compared to air surroundings, the marine environment is not stable due to the influence of ocean currents and other factors. Misalignments always occur inevitably when autonomous underwater vehicles are charging wirelessly in the docking station. Therefore, misalignment insensitive underwater wireless power transfer system need to be investigated. In this article, a novel hybrid transmitter composed of conical and planar spiral coils is proposed that greatly improves the misalignment tolerance and transfer performance. First, the coil tilt angle theory (CTAT) is presented and verified to determine the optimum tilt angle of conical coil. Then, based on the CTAT, a circular uniform magnetic field zone with a diameter of 30 cm in charging plane can be achieved by flexibly designing the hybrid transmitter. Moreover, a three-dimensional finite-element simulation software is employed to study the eddy current loss under different circumstances. Finally, experimental results show that the proposed transmitter has better performance in output power and power transfer efficiency (PTE) stability within the possible working region compared with conventional transmitters. It has demonstrated that the output power changes only within 5.7&#x0025; and the PTEs maintain at approximately 86&#x0025; in excessive misalignment area with transfer distance of 2 cm.

Micro-displacement detection of nanofluidic fluorescent particles based on waveguide-concentric ring resonator model

The dynamic tracking and detecting of nanoparticles in micro-nanofluids have always been a challenging and demanding task. In this work, an integrated model of waveguide-concentric ring resonator is proposed based on the waveguide-concentric ring resonator. The change of the fluorescence power intensity outputted by the cavity coupling structure is used to realize the micro-displacement detection of nanoparticles in the micro-nano fluid. Because the ring micro-resonator has the characteristics of high &lt;i&gt;Q&lt;/i&gt; and the sensitivity to the surrounding environment, the sensitivity of the device is greatly improved. The finite-difference time domain method is used to study the parameters such as the polarization state of the fluorescence and the distance between the two ring resonators. The double-peak change of the fluorescence output power can be used to detect the displacement of the nanoparticles with high precision. Based on the synchronization of the double-peak changes, the detection can reduce the influence of environmental noise and improve the detection accuracy. The numerical simulation results also confirm that this method can measure the micro-displacement of nanoparticles in nanofluids in a range of 0–1000 nm, providing new directions and ideas.

Operation of the transformer at low power quality

Changes in the quality parameters of power supply are considered from the point of view of the connectedness of the voltage level of its drops and unevenness (dips) with active and reactive power. The paper considers the static characteristics of the load in the form of a second-order polynomial depending on the voltage. The authors use the regulating effects of active and reactive loads in accordance with the voltage, showing the percentage of the output power changes when the voltage deviates. The authors accept the limitation on the amount of power losses at the consumer, which is recalculated in the regulating effects of the load. Thus, the voltage reduction range for the industrial load is also set. Provided that the reactive power compensation devices used in electrical systems are intended primarily for unloading networks from reactive currents, as a result of reactive power compensation, a negative effect of increasing the total power consumption may appear. The main goal of the article is to show the possibility of minimizing the losses of active and reactive power in transformers with regulation of the voltage level in the network. Power losses in a power transformer consist of no-load losses and load losses. No-load losses are due to eddy current losses of steel and hysteresis losses. Load losses in a transformer are proportional to the square of the load current. The article determines the optimal voltage at the input of the transformer, at which the total losses of the active power of the transformer will be minimal. Power losses are analytically determined as a function of the relative voltage level due to equating the derivative of voltage losses to zero. Thus, the ratio of minimizing electricity losses in the transformer at the average voltage level at the input of the transformer, which corresponds to the minimum energy losses in the transformer at variable load, has been obtained.

Pump pulse characteristics of quasi-continuous-wave diode-side-pumped Nd:YAG laser

The influence of pumping laser pulse on the property of quasi-continuous-wave (QCW) diode-side-pumped Nd:YAG laser is investigated theoretically and experimentally. Under remaining a fixed duty cycle, the average output power increases, and the corresponding thermal focal length shorten with the increase of the pump pulse duration, which attributes to the decrease of the ratio of pulse buildup time to the pulse duration. At a pump power of 146 W, the laser output power changes from 65.1 W to 81.2 W when the pulse duration is adjusted from 150 μs to 1000 μs, confirming a significant enhancement of 24.7%. A laser rate equation model incorporating the amplified spontaneous emission is also utilized and numerically solved, and the simulated results agree well with the experimental data.