THE WORK OF AN ACTIVE CURRENT CORRECTOR AT LOW LOAD POWER EXAMINATION

Author(s):  
V.M. Spirin ◽  
◽  
V.M. Gubarevych ◽  
V.G. Grebenyuk ◽  
S.V. Salko ◽  
...  
Keyword(s):  
Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1889 ◽  
Author(s):  
Nicu Bizon ◽  
Valentin Alexandru Stan ◽  
Angel Ciprian Cormos

In this paper, a systematic analysis of seven control topologies is performed, based on three possible control variables of the power generated by the Fuel Cell (FC) system: the reference input of the controller for the FC boost converter, and the two reference inputs used by the air regulator and the fuel regulator. The FC system will generate power based on the Required-Power-Following (RPF) control mode in order to ensure the load demand, operating as the main energy source in an FC hybrid power system. The FC system will operate as a backup energy source in an FC renewable Hybrid Power System (by ensuring the lack of power on the DC bus, which is given by the load power minus the renewable power). Thus, power requested from the batteries’ stack will be almost zero during operation of the FC hybrid power system based on RPF-control mode. If the FC hybrid power system operates with a variable load demand, then the lack or excess of power on the DC bus will be dynamically ensured by the hybrid battery/ultracapacitor energy storage system for a safe transition of the FC system under the RPF-control mode. The RPF-control mode will ensure a fair comparison of the seven control topologies based on the same optimization function to improve the fuel savings. The main objective of this paper is to compare the fuel economy obtained by using each strategy under different load cycles in order to identify which is the best strategy operating across entire loading or the best switching strategy using two strategies: one strategy for high load and the other on the rest of the load range. Based on the preliminary results, the fuel consumption using these best strategies can be reduced by more than 15%, compared to commercial strategies.


2021 ◽  
pp. 026921552110034
Author(s):  
Nico Nitzsche ◽  
Alexander Stäuber ◽  
Samuel Tiede ◽  
Henry Schulz

Objective: This meta-analysis aimed to evaluate the effectiveness of low-load Resistance Training (RT) with or without Blood Flow Restriction (BFR) compared with conventional RT on muscle strength in open and closed kinetic chains, muscle volume and pain in individuals with orthopaedic impairments. Data sources: Searches were conducted in the PubMed, Web of Science, Scopus and Cochrane databases, including the reference lists of randomised controlled trials (RCT’s) up to January 2021. Review method: An independent reviewer extracted study characteristics, orthopaedic indications, exercise data and outcome measures. The primary outcome was muscle strength of the lower limb. Secondary outcomes were muscle volume and pain. Study quality and reporting was assessed using the TESTEX scale. Results: A total of 10 RCTs with 386 subjects (39.2 ± 17.1 years) were included in the analysis to compare low-load RT with BFR and high or low-load RT without BFR. The meta-analysis showed no significant superior effects of low-load resistance training with BFR regarding leg muscle strength in open and closed kinetic chains, muscle volume or pain compared with high or low-load RT without BFR in subjects with lower limb impairments. Conclusion: Low-load RT with BFR leads to changes in muscle strength, muscle volume and pain in musculoskeletal rehabilitation that are comparable to conventional RT. This appears to be independent of strength testing in open or closed kinetic chains.


2021 ◽  
Vol 9 (1) ◽  
pp. 12
Author(s):  
Ming D. Lim ◽  
Damian P. Birney

Emotional intelligence (EI) refers to a set of competencies to process, understand, and reason with affective information. Recent studies suggest ability measures of experiential and strategic EI differentially predict performance on non-emotional and emotionally laden tasks. To explore cognitive processes underlying these abilities further, we varied the affective context of a traditional letter-based n-back working-memory task. In study 1, participants completed 0-, 2-, and 3-back tasks with flanking distractors that were either emotional (fearful or happy faces) or non-emotional (shapes or letters stimuli). Strategic EI, but not experiential EI, significantly influenced participants’ accuracy across all n-back levels, irrespective of flanker type. In Study 2, participants completed 1-, 2-, and 3-back levels. Experiential EI was positively associated with response times for emotional flankers at the 1-back level but not other levels or flanker types, suggesting those higher in experiential EI reacted slower on low-load trials with affective context. In Study 3, flankers were asynchronously presented either 300 ms or 1000 ms before probes. Results mirrored Study 1 for accuracy rates and Study 2 for response times. Our findings (a) provide experimental evidence for the distinctness of experiential and strategic EI and (b) suggest that each are related to different aspects of cognitive processes underlying working memory.


Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2539
Author(s):  
Zhengjie Li ◽  
Zhisheng Zhang

At present, due to the errors of wind power, solar power and various types of load forecasting, the optimal scheduling results of the integrated energy system (IES) will be inaccurate, which will affect the economic and reliable operation of the integrated energy system. In order to solve this problem, a day-ahead and intra-day optimal scheduling model of integrated energy system considering forecasting uncertainty is proposed in this paper, which takes the minimum operation cost of the system as the target, and different processing strategies are adopted for the model. In the day-ahead time scale, according to day-ahead load forecasting, an integrated demand response (IDR) strategy is formulated to adjust the load curve, and an optimal scheduling scheme is obtained. In the intra-day time scale, the predicted value of wind power, solar power and load power are represented by fuzzy parameters to participate in the optimal scheduling of the system, and the output of units is adjusted based on the day-ahead scheduling scheme according to the day-ahead forecasting results. The simulation of specific examples shows that the integrated demand response can effectively adjust the load demand and improve the economy and reliability of the system operation. At the same time, the operation cost of the system is related to the reliability of the accurate prediction of wind power, solar power and load power. Through this model, the optimal scheduling scheme can be determined under an acceptable prediction accuracy and confidence level.


Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 179
Author(s):  
M. M. A. Baig ◽  
M. Abdul Samad

Epoxy composite coating systems generally find their usage in applications such as, fluid handling systems to protect components from corrosive media. However, their use in demanding tribological applications such as, in sliding components of machines, are known to be limited. This is often attributed to their low load bearing capacity combined with poor thermal stability under severe p-v regimes. Researchers have tried to enhance the tribological properties of the epoxy coatings using a combination of several types of micro/nano sized fillers to produce composite or hybrid composite coatings. Hence, this review paper aims to focus on the recent advances made in developing the epoxy coating systems. Special attention would be paid to the types and properties of nano-fillers that have been commonly used to develop these coatings, different dispersion techniques adopted and the effects that each of these fillers (and their combinations) have on the tribological properties of these coatings.


Author(s):  
Junshuai Liang ◽  
Ning Li ◽  
Jingyu Zhai ◽  
BaoGang Wen ◽  
Qingkai Han ◽  
...  

In this study, a layering method of carburized ring is presented. A finite element (FE) model for analyzing bearing stiffness characteristics is established considering the residual stress in the carburized layer. The residual stress in the carburized layer of a double-row conical roller bearing is tested and the influence of the distribution of residual stress in carburized layer on the bearing stiffness is investigated. Results show that the residual stress in the carburized layer increases the contact stiffness of the bearing by 5% in the low-load zone and 3% in the high-load zone. The radial stiffness of the bearing is increased by 5% in the low-load zone and 3% in the high-load zone. The axial stiffness is increased by 6%, and the angular stiffness increased by 4%. The larger the thickness of the carburized layer, the greater the residual compressive stress in the carburized layer, the deeper the position of the maximum residual stresses in the carburized layer will lead to the greater stiffness of the bearing.


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