Increase In Output Power Research Articles

Experimental study on the effects of salt solution pH on the performance of reverse electrodialysis stack

Reverse electrodialysis (RED) is a promising way of harvesting salinity gradient energy (SGE). The seawater or industrial wastewater may have various pHs. Here the RED performance involving sodium salt solutions with different ion valence ratios including anions of Cl-, SO42-, and PO43- is experimentally investigated in symmetric and asymmetric pH configurations. In the symmetrical pH configuration, increasing the solution pH significantly weakens the energy conversion performance for the 1:1 and 1:3 salts; for the 1:2 salt, the power density and energy conversion efficiency increase and then decrease with increasing pH due to the coupling effects of OH- on the ion transportation through AEMs and CEMs. In the asymmetric pH configuration, increasing the pH of the low concentration solution decreases the power density and energy conversion efficiency. As the pH of the high concentration solution increases, the output power and energy conversion efficiency decrease and then increase for the 1:1 salt due to the coupling effects of the ion transmembrane concentration difference and OH- on the ion migration of IEMs; for the 1:2 salt, the output power and energy conversion efficiency increase and then decrease; for the 1:3 salt, OH- inhibits the hydrolysis of Na3PO4 and anion migration, leading to the lowered output power density and energy efficiency.

Theoretical analysis on improving output power of continuous-wave single-wavelength two-photon pumped Rb-vapor laser with mid-infrared seed laser

We theoretically prove that introducing 5.23-μm mid-infrared (MIR) seed laser can greatly increase output power of two-photon pumped Rb-vapor laser (Rb-TPAL) for the first time. Firstly, MIR laser stimulated radiation is added to the three-dimensional calculation model we reported in Ref. [1]. Then we simulate the Rb-TPAL pumped by a high-power continuous-wave laser diode and analyze the effects of MIR seed power and direction, vapor cell temperature and length, waist radii of pump and MIR seed, and output mirror reflectance on the output characteristics. The results show that by optimizing the above parameters, the MIR seed laser can not only significantly improve the output power and conversion efficiency of blue and MIR laser, but also reduce the pump and temperature thresholds of blue laser. This study can be useful for designing a TPAL system with high-power dual-waveband laser output.

The influence of friction between elements of dual-mass flywheel on oscillatory phenomena in a car transmission

Automobile manufacturers, when designing new cars, are increasingly faced with the need to reduce the weight of components in order to achieve the required level of fuel consumption and environmental standards. As a result, internal combustion engines (ICEs) with a small number of cylinders are designed and manufactured, which allows to achieve an increase in output power due to increased pressure in the cylinder and more efficient fuel combustion. As a result of this, torsional vibrations occur on the crankshaft, which are transmitted and negatively affect the transmission, causing it to fail prematurely. The damping properties of dual-mass flywheel (DMF) in a straight line depend on their structure and design parameters. All modern DMF contain a certain amount of thick lubricant, which in one way or another improves its characteristics. But in addition to parts, flywheels that constantly work in an environment with lubricant, there are also elements between which dry friction occurs, which also affects the damping characteristics of the flywheel. Therefore, it can be assumed that its presence affects the elastic-damping properties of the DMF. The purpose of the work is to develop simulation models and study the effect of friction between DMF elements on oscillatory processes in the car transmission and to develop recommendations for reducing the load on DMF elements and transmission links. The effect of dry and viscous friction between the elements of a DMF on the damping of oscillations in the links of its elastic-damping system and the drive links of the car was studied. It is shown that an increase in the coefficient of dry friction between DMF elements from 0 to 0.3 does not provide a noticeable damping of oscillations in the drive links and tension in the DMF springs. The coefficient of viscous friction between the links of the DMF has a significant influence on the amount of tension in the springs of the DMF. To increase the resource of the DMF, it is advisable to install separators made of polymer material between the elastic links with a small coefficient of friction between it and the steel body of the DMF.

Luminescence efficiency improvement of small-size micro light-emitting diodes by a digital etching technology.

The decrease of light output efficiency with the reduction of LED (light-emitting diode) die size is one of the challenges of micro-LED displays. Here we propose a digital etching technology that employs multi-step etching and treatment to mitigate sidewall defects exposed after mesa dry etching. In this study, by two-step etching and N2 treatment, the electrical properties of the diodes show an increase of forward current and a decrease in reverse leakage due to suppressed sidewall defects. An increase of light output power by 92.6% is observed for 10 × 10-µm2 mesa size with digital etching, as compared with that with only one step etching and no treatment. We also demonstrated only 1.1% decrease in output power density for a 10 × 10-µm2 LED as compared with a 100 × 100-µm2 device without performing digital etching.

Design of solar cell using mirror, cooling, double axis, and solar tracking

Fossil energy sources are dwindling. It is necessary to develop alternative energy sources for future energy. The solar cell is an alternative energy that can be used in Indonesia. The current challenge is utilizing solar panels for the best possible power production. This research gives the solution to design an increase in solar cell output power by using mirrors, cooling, and a double-axis solar tracking control system. The results show that using a mirror, cooling, and double-axis solar tracking produces optimal output power with a current and power are 2.43 amperes and 40.3 watts, respectively. Meanwhile, several factors can affect this solar panel's efficiency. Specifically, the amount of solar radiation that the solar panel can receive depends on the climate on the day and location of the research and the solar panel's dimensions.

Geometric Design Optimisations Towards Improved Power Production Within Alkaline Carbohydrate Fuel Cells

Though direct carbohydrate fuel cells offer a highly efficient pathway from abundant, non-toxic sugars to electricity, currently their potential remains untapped due to a lack of knowledge of the impact of different cell geometries on their output power. In this work, simple modifications to the configuration of carbohydrate fuel cells are shown to significantly impact the performance of alkaline carbohydrate fuel cells. Increasing the density of a metal foam anode from 250 to 1000 mg cm−3 was found to increase power output by up to ∼30%. These anode density changes also affected optimal fuel concentrations, which dropped from 1 M to 0.75 M. Decreasing the distance between electrodes from 20 mm to 6 mm resulted in improved maximum power outputs of ∼35%. Identifying these new loss mechanisms in this device type provides a basis to optimise alkaline carbohydrate fuel cell performance and provide insights that help reconcile some of the disparities observed throughout the research space.

High Efficiency Bidirectional Dual Active Bridge (DAB) Converter Adopting Boost-Up Function for Increasing Output Power

In this article, we proposed a bidirectional dual active bridge (DAB) converter adopting a boost-up function. The proposed converter can be implemented by adding only one capacitor to the high voltage side without additional active components. By utilizing the boost-up function, the proposed converter can achieve higher output power than the conventional DAB converter under the same leakage inductance condition. In comparison with the resonant converter in addressing the output power limitation, the proposed converter can reduce the switching and conduction losses due to the low turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> and circulating currents, and complex control is not required to drive the synchronous rectifier. Furthermore, the direction of the output power can be easily changed with a simple control circuit. Experimental results from the proposed converter with a 3 kW rated power, 28-V low-side voltage, and 600-V high-side voltage are demonstrated to verify the proposed works.

The effect of a pressure ventilatory support on quadriceps endurance is maintained after exercise training in severe COPD patients. A longitudinal randomized, cross over study.

Purpose: In severe chronic obstructive pulmonary disease (COPD) patients, the application of an inspiratory pressure support (IPS) during exercise increases exercise tolerance and the benefit of exercise training during pulmonary rehabilitation (PR). Moreover, it improves quadriceps endurance after a session of cycling exercise suggesting a reduced muscle fatigue. We looked for the persistence of this effect after PR and sought an association between the improved quadriceps endurance with IPS and the training load during PR. Patients and methods: We studied 20 patients with severe COPD (6 in stage 3and 14 in stage 4 of GOLD) before and after PR. As part of a PR program, patients completed 16 cycling sessions over 6 weeks with the addition of IPS during exercise. As a surrogate of muscular fatigue, quadriceps endurance was measured at 70% of maximal strength in a control condition, after a constant work rate exercise test (CWR) with IPS (TlimQ IPS) or with a sham ventilation (TlimQsham), in a random order. These tests were repeated similarly at the end of PR. Results: PR was associated with a significant increase in maximal power output, cycling endurance, quadriceps strength and endurance. Session training load (power output x duration of the session) increased by 142% during the course of the program. Before PR, CWR duration increases with IPS compared to sham ventilation (Δtime = +244s, p = 0.001). Compared to control condition, post-exercise TlimQ reduction was lower with IPS at isotime than at the end of CWR or than with sham ventilation (-9 ± 21%, -18 ± 16% and -23 ± 18%, respectively, p = 0.09, p < 0.0001 and p < 0.0001). After PR, the post-exercise decrease of TlimQ was reduced after IPS compared to sham (-9 ± 18% vs. -21 ± 17%, respectively, p = 0.004). No relationship was found between the prevention of quadriceps fatigue and the training load. Conclusion: In severe COPD patients, the beneficial effect of a ventilator support on quadriceps endurance persisted after PR with IPS. However, it was not related to the increase in training load, and could not predict the training response to non-invasive ventilation during exercise.

Performance improvement of single-junction photovoltaic systems using a new design of a heat pipe-based heat sink: Experimental study

A newly integrated single-junction PV-heat pipe system with an innovative heat sink design comprised of an elliptical cross-section area and varied aspect ratios is proposed and experimentally investigated. Unlike the prior systems, the proposed one fits the requirements for practical applications, such as adequate cooling efficiency, ease in manufacturing, reliability, low operating and maintenance costs, noiseless and powerless operation, and so increases total system efficiency. Several experiments were carried out indoors to examine the effect of using four working fluids (Pure water, Ethanol, Methanol, and Ethylene Glycol based water solution (50 % by volume), four distinct charging ratios (50, 60, 70, and 80 %), and different heat loads to mimic the absorbed energy due to incident solar irradiance received by the solar cell. The results showed that the heat pipe with an elliptical cross-section area performed better than the one with a circular cross-section area with more than 300 W/m2 increase in heat absorbed rate at 50 ℃ oil temperature and more than 2700 W/m2 increase in heat absorbed rate at 90 ℃ oil temperature. Furthermore, when compared to other working fluids and charging ratios, the heat pipe filled with Ethanol as the working fluid and a charge ratio of 70 % performs better for all operating temperatures tested and aspect ratio. The reduction in PV module temperature ranging from 9 to 16.36 ℃ depends on the working fluid, charging ratio and the operating temperature. While the increase in the PV module output power ranging from 4 to 8.18 % at the different working fluids, charging ratios and operating temperatures.

Experimental investigation and validation of solar PV cooling for enhanced energy conversion efficiency for Indian climatic conditions

Solar Photovoltaic (PV) cells convert an average of 10 to 15% of the incident solar radiation into electricity and remaining energy is wasted as unused heat energy. The p erformance of solar PV is largely dependent on its operating temperature, which is again dependent on solar irradiation. The efficiency of solar PV reduces the higher PV temperature due to charge carrier recombination. The solar PV efficiency drops considerably wit h increasing temperature. Dust deposition on the surface of solar PV cells reduce incident energy and no technology is commercially available to mitigate the problem. The objective of the present work is to enhance the energy conversion efficiency of solar PV by adopting Front Water (FW) cooling technique. The FW cooling technique maintains the cell temperature at Standard Test Conditions (STC) irrespective of ambient air conditions and also washes away dust deposits, thereby providing maximum energy conversion efficiency specified by the cell manufacturer during the operation with increased lifecycle of solar cells. The experiment was carried out on a 100 W solar panel for a period of 2 weeks and data acquisition system with Arduino controller was used to analyze and maintain STC of the panel to obtain maximum power. The mathematical model of the system was analyzed and obtained results were in good agreement with the experimental measurements. The solar PV panel with FW cooling yielded an efficiency improvement of 9% with 17 W of increased power output at Maximum Power Point (MPP). MATLAB Simulink software is used to model t he FW cooling technique. The model is able to predict the power generated by the solar PV cells for the given irradiance with and without cooling. The developed model can now be utilized to design cooling systems for larger installation of solar PV systems.

Agent-based effectiveness evaluation method and impact analysis of airborne laser weapon system in cooperation combat

The laser weapons will play a special role in the future high-tech war. To study the impact of airborne laser weapon on the System-of-System (SoS) effectiveness in cooperative combat, this paper proposes an indicator construction method based on the combination of the weapon capability indicator system and the combat simulation. The indicator system of capability is divided into 4 layers by the bottom-to-up generation mechanism of indicators. It can describe the logical relationship between the indicator layers from a qualitative perspective. Together with the 4 layers capability indicator system, a hierarchical framework of airborne laser weapon is established by the agent-based modeling and simulation. Impact analyses show that the SoS effectiveness improves with the increase of the laser weapon output power, the laser launcher diameter, and the photoelectric sensor pixel. But the SoS effectiveness promotion brought by the photoelectric sensor pixel is limited. The results can be used for the development of tactical airborne laser weapon.

Row spacing as a controller of solar module temperature and power output in solar farms

When the temperature of solar photovoltaic modules rises, efficiency drops and module degradation accelerates. The spatial arrangement of solar modules can affect convective cooling and, consequently, module temperatures. However, the impact of row spacing on convective cooling in realistic solar farms has not yet been studied. Here, we develop six solar farm arrangements consisting of a fixed number of rows with varying streamwise row spacing. We model the flow and heat transfer of each solar farm using high-resolution large-eddy simulations. Results indicate that increasing row spacing can enhance convective cooling by 14.8%, which reduces module temperature by 6.6 °C and increases power output by 4.0% on average.

Thermofluids analysis of combustion, emissions, and energy in a biodiesel (C11H22O2) / natural gas heavy-duty engine with RCCI mode (Part I: Single/ two -stage injection)

• The effects of fuel injection strategy for using the concept of RCCI combustion in a heavy-duty biodiesel engine have been investigated. • For the first time in a heavy-duty biodiesel engine, biodiesel fuel (C 11 H 22 O 2 ) as a new fuel has been used in this level. • Changing the high reactivity fuel injection time from -40° to -60°, the rate of heat released decreases but output power increases. • The mass of HC and CO pollutants has drastically decreased with the onset of injection earlier. One of the novel methodologies used to increase energy efficiency and reduction of environmental pollutants in internal combustion engines is the idea of low-temperature combustion (LTC) especially reactivity controlled compression ignition (RCCI). Given that the ultimate goal of RCCI combustion is combustion controllability through in-cylinder reactivity stratification by using two different fuels, there are many modifiable factors, which can be improved or adjusted. The aim of this research is to use the concept of RCCI combustion in a biodiesel (C 11 H 22 O 2 ) / natural gas heavy-duty engine and the performance and amount of pollutants of engine output is evaluated and compared by modifying the input parameters (different fuel injection strategy). Accordingly, numerical simulations have been carried out to study combustion in the geometry of the Caterpillar 3401E engine with CONVERGE computational fluid dynamic software and the SAGE combustion model. Results show that: By changing the biodiesel injection time (from -40° to -60°), although, the rate of heat released decreases, output work and Indicated mean effective pressure (IMEP) increase. By increasing the lag of time between the first and second injections (in Cases 1–3), the IMEP will increase from 6.9 to 8.2 bar and the work from 1686 to 1997 J. In Cases (7–9), the mass of HC and CO pollutants has drastically decreased with the onset of injection earlier, whereas the mass of NOx pollutants has increased.

Short-Term Creatine Supplementation and Repeated Sprint Ability-A Systematic Review and Meta-Analysis.

The aim of this study was to conduct a systematic review and meta-analysis of the effects of short-term creatine supplementation on repeated sprint ability. Fourteen studies met the inclusion criteria of adopting double-blind randomized placebo-controlled designs in which participants (age: 18-60years) completed a repeated sprint test (number of sprints: 4 < n ≤ 20; sprint duration: ≤10s; recovery duration: ≤90s) before and after supplementing with creatine or placebo for 3-7days in a dose of ∼20g/day. No exclusion restrictions were placed on the mode of exercise. Meta-analyses were completed using random-effects models, with effects on measures of peak power output, mean power output, and fatigue (performance decline) during each repeated sprint test presented as standardized mean difference (δ), and with effects on body mass and posttest blood lactate concentration presented as raw mean difference (D). Relative to placebo, creatine resulted in a significant increase in body mass (D = 0.79kg; p < .00001) and mean power output (δ = 0.61; p = .002). However, there was no effect of creatine on measures of peak power (δ = 0.41; p = .10), fatigue (δ = 0.08; p = .61), or posttest blood lactate concentration (D = 0.22L/min; p = .60). In conclusion, creatine supplementation may increase mean power output during repeated sprint tests, although the absence of corresponding effects on peak power and fatigue means that more research, with measurements of intramuscular creatine content, is necessary to confirm.

Mathematical simulation of autonomous wind electric installation with magnetoelectric generator

Purpose. Development of a mathematical model of an autonomous wind power plant based on an end-generator with a double stator and combined excitation to evaluate methods for improving the efficiency of conversion of mechanical wind energy into electricity. Methodology. The research used methods of general theory of wind power plants, methods of mathematical modeling, which are based on the numerical solution of nonlinear differential equations to evaluate methods for correcting the output power in Matlab-Simulink by modifying standard units. Findings. A numerical simulation mathematical model of an autonomous wind power plant consisting of a magnetoelectric generator with an axial magnetic flux with combined excitation and a double stator has been developed. The model was created to study the parameters and characteristics of the installation, as well as to evaluate methods and means to improve the efficiency of conversion of wind energy into electricity. According to the research, it is established that a more effective method for regulating the output power of the generator in the wind turbine is the use of additional winding for magnetization, compared with the use of additional capacity. The latter provides up to 716% increase in output power, while using the magnetizing winding can increase the output power to 3235%. The results obtained by the authors allow further developing a number of methods to increase the efficiency of conversion of mechanical energy of the wind turbine rotor into electrical energy. Originality. The mathematical model developed for the first time, in contrast to the existing ones, takes into account the presence of a double stator, an additional winding for magnetization of the magnetic system and the axial nature of the circuit of the main and additional magnetic flux. The developed model also takes into account the change in the parameters of the electric generator with axial magnetic flux when changing the parameters of the wind, the rotor of the wind turbine and the load. The model is designed to analyze the possibility of adjusting the output power of the generator when the wind speed changes. Practical value. The simulation results indicate the prospects of industrial implementation of wind power plant based on magnetoelectric generator for their use as autonomous electrical installations and as part of shunting power systems.

Half-disk lasers with active region based on InGaAs/GaAs quantum well-dots

Half-disk lasers fabricated by cleaving initial full-disk lasers have an advantage of directional light outcoupling as well as increased output power and efficiency as compared to full-disk lasers of the same diameter. The continuous wave output power of a 200 µm diameter half-disk laser exceeds 70 mW. Quasi single-mode lasing with a high side-mode suppression ratio more than 20 dB is demonstrated for half-disk lasers of various diameters. A maximum 3 dB small signal modulation frequency of 4.9 GHz was measured for a 100 µm in diameter half-disk laser.

The Acute Cytokine Response to 30-Minute Exercise Bouts Before and After 8-Week Endurance Training in Individuals With Obesity.

One acute bout of exercise leads to a rapid increase in the systemic cytokine concentration. Regular exercise might alter the cytokine response, in particular in beforehand untrained and obese individuals. Using a proximity extension assay, we studied the effects of acute exercise as well as endurance training on a panel of 92 cytokines related to inflammation. A total of 22 individuals (30 ± 9 years; peak oxygen uptake [VO2peak] 25.2 ± 4.2 mL/[kg × min]; body mass index [BMI] 31.7 ± 4.4) participated in an 8-week endurance exercise intervention. Blood samples were collected before and immediately after 30 minutes' ergometer exercise at 80% VO2peak. Before and after the training intervention, 40 and 37 cytokines, respectively, were acutely increased more than 1.2-fold (Benjamini-Hochberg [BH]-adjusted P < .05). The exercise intervention did not change the acute increase in cytokines nor the resting cytokine levels, whereas fitness was improved and adiposity reduced. The increase in fitness led to a slight increase in power output when exercising at the same heart rate, which might explain the comparable increase in cytokines before and after the intervention. The largest acute increase was found for OSM, TGFA, CXCL1 and 5, and TNFSF14 (≥ 1.9-fold, BH-adjusted P < .001). The transcript levels of these proteins in whole blood were also elevated, particularly in the trained state. Only the acute increase in IL6 (1.3-fold) was related to the increase in lactate, confirming the lactate-driven secretion of IL6. Our comprehensive proteomics approach detected several underexplored serum exerkines with up to now less understood function in the adaptation to exercise.

High-power distributed feedback lasers with high-order surface curved gratings.

A novel, to the best of our knowledge, broad-area distributed feedback laser with high-order surface curved gratings has been fabricated based on standard near ultraviolet lithography. The characteristics of increasing output power and mode selection are achieved simultaneously by using a broad-area ridge as well as an unstable cavity structure composed of curved gratings and a high-reflectivity coated rear facet. Suppression of high-order lateral modes is realized by setting current injection/non-injection regions and asymmetric waveguides. This DFB laser emitting around 1070 nm has achieved a spectral width of 0.138 nm and a maximum output power of 915 mW kink-free optical power. The threshold current and side-mode suppression ratio of the device are 370 mA and 33 dB, respectively. The simple manufacturing process and stable performance give this high-power laser broad application prospects in the fields of light detection and ranging, laser pumps, optical disk access, etc.

Single Axis Passive Solar Tracker Performance Evaluation

A passive solar tracker was designed and constructed in GIAD Industrial Complex. The tracker was tested in Soba region, in the premises of the National Energy Research Center. The test consisted of two parts; the first was testing the tracking error by placing a pyranometer on the tracker and comparing the beam radiation readings with that of the maximum theoretical beam radiation possible if the tracker was tracking without errors. The second test was comparing the power output of 8, 50Wp photovoltaic modules attached onto the tracker in tracking mode to the same modules on the tracker fixed in a straight position. The array is inclined to 15.5o facing South. The results showed that most of the tracking error was within the range of 7.37 %. The photovoltaic array comparison test showed that the tracker is most effective in the morning hours from 9:00 to 11:00 and in the afternoon from 15:00 to 17:00. The increase of power output of the tracked array to the fixed array was 12.67% on the day of 9thDecember and 14.39% on the day of 11thApril.

Stabilising function of the human diaphragm in response to involuntary augmented breaths induced with or without lower-limb movements.

What is the central question of this study? Is the stabilising function of the diaphragm altered differentially in response to involuntary augmented breathsinduced with or without lower-limb movements? What is the main finding and its importance? At equivalent levels of ventilation, the diaphragm generated higher passive pressure but moved significantly less during incremental cycle ergometry compared with progressive hypercapnia. Diaphragm excursion velocity and power output did not differ between the two tasks. These findings imply that the power output of the diaphragm during stabilising tasks involving the lower limbs may be preserved via coordinated changes in contractile shortening. Activity of key respiratory muscles, such as the diaphragm, must balance the demands of ventilation with the maintenance of stable posture. Our aim was to test whether the stabilising function of the diaphragm would be altered differentially in response to involuntary augmented breaths induced with or without lower-limb movements. Ten healthy volunteers (age 21 (2) years; mean (SD)) performed progressive CO2 -rebreathe (5% CO2 , 95% O2 ) followed 20min later by incremental cycle exercise (15-30W/min), both in a semi-recumbent position. Ventilatory indices, intrathoracic pressures and ultrasonographic measures of diaphragm shortening were assessed before, during and after each task. From rest to iso-time, inspiratory tidal volume and minute ventilation increased two- to threefold. At equivalent levels of tidal volume and minute ventilation, mean inspiratory transdiaphragmatic pressure ( ) was consistently higher during exercise compared with CO2 -rebreathe due to larger increases in gastric pressure and the passive component of (i.e., mechanical output due to static contractions), and yet diaphragm excursion was consistently lower. This lower excursion during exercise was accompanied by a reduction in excursion time with no difference in the active component of . Consequently, the rates of increase in excursion velocity (excursion/time) and power output (active × velocity) did not differ between the two tasks. In conclusion, the power output of the human diaphragm during dynamic lower-limb exercise appears to be preserved via coordinated changes in contractile shortening. The findings may have significance in settings where the ventilatory and stabilising functions of the diaphragm must be balanced (e.g., rehabilitation).