Thermodynamic Efficiency, Power Output and Performance Indices of Classic and Nanostructured Thermoelectric Materials

2011 ◽  
Vol 1 (1) ◽  
pp. 63-70 ◽  
Author(s):  
Dario Narducci
Keyword(s):  
Thermoelectric Materials ◽  
Power Output ◽  
Thermodynamic Efficiency ◽  
Performance Indices ◽  
And Performance ◽  
Nanostructured Thermoelectric Materials

Pavonite homologues as potential n-type thermoelectric materials: crystal structure and performance

2021 ◽  
Author(s):  
Shangqing Qu ◽  
Jing Zhao ◽  
Zimin Jiang ◽  
Dequan Jiang ◽  
Yonggang Wang
Keyword(s):  
Crystal Structure ◽  
Thermoelectric Material ◽  
Thermoelectric Materials ◽  
Homologous Series ◽  
And Performance

The pavonite homologous series assembled from two basic modules is a potential n-type thermoelectric material.

scholarly journals Sectorization for Water Distribution Systems with Multiple Sources: A Performance Indices Comparison

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 131
Author(s):  
Jezabel D. Bianchotti ◽  
Melina Denardi ◽  
Mario Castro-Gama ◽  
Gabriel D. Puccini
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Distribution Networks ◽  
Performance Criteria ◽  
Performance Indices ◽  
Multiple Sources ◽  
Multiobjective Problems ◽  
Open Questions ◽  
Minimum Number ◽  
And Performance

Sectorization is an effective technique for reducing the complexities of analyzing and managing of water systems. The resulting sectors, called district metering areas (DMAs), are expected to meet some requirements and performance criteria such as minimum number of intervention, pressure uniformity, similarity of demands, water quality and number of districts. An efficient methodology to achieve all these requirements together and the proper choice of a criteria governing the sectorization is one of the open questions about optimal DMAs design. This question is addressed in this research by highlighting the advantages of three different criteria when applied to real-word water distribution networks (WDNs). To this, here it is presented a two-stage approach for optimal design of DMAs. The first stage, the clustering of the system, is based on a Louvain-type greedy algorithm for the generalized modularity maximization. The second stage, the physical dividing of the system, is stated as a two-objective optimization problem that utilises the SMOSA version of simulated annealing for multiobjective problems. One objective is the number of isolation valves whereas for the second objective three different performance indices (PIs) are analyzed and compared: (a) standard deviation, (b) Gini coefficient and (c) loss of resilience. The methodology is applied to two real case studies where the first two PIs are optimized to address similar demands among DMAs. The results demonstrate that the proposed method is effective for sectorization into independent DMAs with similar demands. Surprisingly, it found that for the real studied systems, loss of resilience achieves better performance for each district in terms of pressure uniformity and demand similarity than the other two specific performance criteria.

Optimum Design and Performance Simulation of a Multi-device Integrated System Based on a Proton Exchange Membrane Fuel Cell

2022 ◽  
pp. 1-33
Author(s):  
Xiuqin Zhang ◽  
Wentao Cheng ◽  
Qiubao Lin ◽  
Longquan Wu ◽  
Junyi Wang ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Power Density ◽  
Power Output ◽  
Proton Exchange Membrane ◽  
Waste Heat ◽  
Proton Exchange ◽  
Integrated System ◽  
Interior Space ◽  
And Performance ◽  
Exchange Membrane

Abstract Proton exchange membrane fuel cells (PEMFCs) based on syngas are a promising technology for electric vehicle applications. To increase the fuel conversion efficiency, the low-temperature waste heat from the PEMFC is absorbed by a refrigerator. The absorption refrigerator provides cool air for the interior space of the vehicle. Between finishing the steam reforming reaction and flowing into the fuel cell, the gases release heat continuously. A Brayton engine is introduced to absorb heat and provide a useful power output. A novel thermodynamic model of the integrated system of the PEMFC, refrigerator, and Brayton engine is established. Expressions for the power output and efficiency of the integrated system are derived. The effects of some key parameters are discussed in detail to attain optimum performance of the integrated system. The simulation results show that when the syngas consumption rate is 4.0 × 10−5 mol s−1cm−2, the integrated system operates in an optimum state, and the product of the efficiency and power density reaches a maximum. In this case, the efficiency and power density of the integrated system are 0.28 and 0.96 J s−1 cm−2, respectively, which are 46% higher than those of a PEMFC.

Physical Demands and Performance Indicators in Male Professional Cyclists During a Grand Tour: WorldTour Versus ProTeam Category

2021 ◽  
pp. 1-9
Author(s):  
Xabier Muriel ◽  
Pedro L. Valenzuela ◽  
Manuel Mateo-March ◽  
Jesús G. Pallarés ◽  
Alejandro Lucia ◽  
...  
Keyword(s):  
Power Output ◽  
Performance Indicators ◽  
Cycling Performance ◽  
Threshold Power ◽  
Grand Tour ◽  
Physical Demands ◽  
Physical Demand ◽  
Stress Score ◽  
And Performance ◽  
Training Stress

Purpose: To compare the physical demands and performance indicators of male professional cyclists of 2 different categories (Union Cycliste Internationale WorldTour [WT] and ProTeam [PT]) during a cycling grand tour. Methods: A WT team (n = 8, 31.4 [5.4] y) and a PT team (n = 7, 26.9 [3.3] y) that completed “La Vuelta 2020” volunteered to participate. Participants’ power output (PO) was registered, and measures of physical demand and physiological performance (kilojoules spent, training stress score, time spent at different PO bands/zones, and mean maximal PO [MMP] for different exertion durations) were computed. Results: WT achieved a higher final individual position than PT (31 [interquartile range = 33] vs 71 [59], P = .004). WT cyclists showed higher mean PO and kilojoule values than their PT peers and spent more time at high-intensity PO values (>5.25 W·kg−1) and zones (91%–120% of individualized functional threshold power) (Ps < .05). Although no differences were found for MMP values in the overall analysis (P > .05), subanalyses revealed that the between-groups gap increased through the race, with WT cyclists reaching higher MMP values for ≥5-minute efforts in the second and third weeks (Ps < .05). Conclusions: Despite the multifactorial nature of cycling performance, WT cyclists spend more time at high intensities and show higher kilojoules and mean PO than their PT referents during a grand tour. Although the highest MMP values attained during the whole race might not differentiate between WT and PT cyclists, the former achieve higher MMP values as the race progresses.

scholarly journals Preparation and Performance of Mg2X-Based Thermoelectric Materials by MgH2 Reaction

2014 ◽  
Vol 26 (17) ◽  
pp. 5852-5856
Author(s):  
Yongzhong Zhang ◽  
Yonghui Han ◽  
Shaoping Chen ◽  
Qingsen Meng
Keyword(s):  
Thermoelectric Materials ◽  
And Performance

scholarly journals Reference evapotranspiration for Londrina, Paraná, Brazil: performance of different estimation methods

2017 ◽  
Vol 38 (4Supl1) ◽  
pp. 2363
Author(s):  
Rodrigo Dlugosz da Silva ◽  
Marcelo Augusto de Aguiar e Silva ◽  
Marcelo Giovanetti Canteri ◽  
Juliandra Rodrigues Rosisca ◽  
Nilson Aparecido Vieira Junior
Keyword(s):  
Reference Evapotranspiration ◽  
Meteorological Data ◽  
Global Radiation ◽  
Alternative Methods ◽  
Estimation Methods ◽  
Performance Indices ◽  
Excellent Performance ◽  
Study Region ◽  
Temperature Radiation ◽  
And Performance

Aiming at assessing the performance of alternative methods to Penman-Monteith FAO56 for estimating the reference evapotranspiration (ETo) for Londrina, Paraná, Brazil, the methods temperature radiation, Hicks-Hess, Hargreaves-Samani (1982), Turc, Priestley-Taylor, Tanner-Pelton, Jensen-Haise, Makkink, modified Hargreaves, Stephens-Stewart, Abtew, global radiation, Ivanov, Lungeon, Hargreaves-Samani (1985), Benavides-Lopez, original Penman, Linacre, Blaney-Morin, Romanenko, Hargreaves (1974), McCloud, Camargo, Hamon, Kharrufa, McGuiness-Bordne, and Blaney-Criddle were compared to that standard method recommended by FAO. The estimations were correlated by linear regression and assessed by using the Person’s correlation coefficient (r), concordance index (d), and performance index (c) using a set of meteorological data of approximately 40 years. The methods modified Hargreaves, Stephens-Stewart, Abtew, global radiation, Ivanov, Lungeon, Hargreaves-Samani (1985), Benavides-Lopez, original Penman, and Linacre should be avoided, as they did not present excellent results. The methods McCloud, Camargo, Hamon, Kharrufa, McGuinness-Bordne, Blaney-Criddle, Hargreaves (1974), Romanenko, and Blaney-Morin were classified as very bad, not being recommended. In contrast, the methods temperature radiation, Hicks-Hess, Hargreaves-Samani (1982), Turc, Priestley-Taylor, Tenner-Pelton, Jensen-Haise, and Makkink presented excellent performance indices and can be applied in the study region.

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