scholarly journals Effect of electrolyte flow on a gas evolution electrode

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Soufiane Abdelghani-Idrissi ◽  
Nicolas Dubouis ◽  
Alexis Grimaud ◽  
Philippe Stevens ◽  
Gwenaëlle Toussaint ◽  
...  

AbstractIn this study, the effect of flow of the electrolyte on an electrolysis cell and a zinc cell is investigated. The gain of energy brought by the flow is discussed and compared to the viscous losses in the cells. We point out that the balance between the gained electrical power and the viscous loss power is positive only if the hydrodynamic resistance of the circuit is correctly designed and further comment on the economical viability of the whole process. A model of the studied phenomena is proposed in the last section. This analytical model captures the dynamics of the process, gives the optimal flowing conditions and the limits of the energetical rentability of the process. This study shows that the use of flowing electrolyte in zinc–air batteries can be energetically profitable with the appropriate flowing conditions.

Author(s):  
Xiangchun Xuan ◽  
Edmond W. K. Young ◽  
Dongqing Li

This work investigated the electrokinetic focusing and dispensing of polystyrene particles and red blood cells on microfluidic chips. Particles or cells were first electrokinetically focused using the merging of focusing streams on the sample stream, and subsequently separated as a result of the focusing. These particles or cells were then selectively dispensed from the focused sample stream using precise application of electrical pulses. The whole process of focusing, separation and dispensing of particles was visualized by a custom-made microscopy system. In particular, the width of the focused fluorescein stream and the accelerated electrophoretic motion of particles and cells were measured in a cross-channel and compared with a proposed analytical model. The electrokinetic manipulation of particles and cells demonstrated in this work can be used for developing integrated lab-on-a-chip devices for studies of cells.


Author(s):  
V. S. N. Ranjith Kumar ◽  
S. Kumar ◽  
G. Pal ◽  
Tushar Shah

Design of high-performance power lines with advanced materials is indispensable to effectively eliminate losses in electrical power transmission and distribution (T&D) lines. In this study, aluminum conductor composite core with carbon nanostructure (ACCC–CNS) coating in a multilayered architecture is considered as a novel design alternative to conventional aluminum conductor steel-reinforced (ACSR) transmission line. In the multiphysics approach presented herein, first, electrothermal finite element analysis (FEA) of the ACSR line is performed to obtain its steady-state temperature for a given current. Subsequently, the sag of the ACSR line due to self-weight and thermal expansion is determined by performing thermostructural analysis employing an analytical model. The results are then verified with those obtained from the FEA of the ACSR line. The electrothermal finite element (FE) model and the thermostructural analytical model are then extended to the ACCC–CNS line. The results indicate that the ACCC–CNS line has higher current-carrying capacity (CCC) and lower sag compared to those of the ACSR line. Motivated by the improved performance of the ACCC–CNS line, a systematic parametric study is conducted in order to determine the optimum ampacity, core diameter, and span length. The findings of this study would provide insights into the optimal design of high-performance overhead power lines.


2018 ◽  
Vol 8 (9) ◽  
pp. 1699 ◽  
Author(s):  
Takashi Ozaki ◽  
Kanae Hamaguchi

We present an analytical model of a flapping-wing actuator, including its electrical, aerodynamic, and mechanical systems, for estimating the lift force from the input electrical power. The actuator is modeled as a two-degree-of-freedom kinematic system with semi-empirical quasi-steady aerodynamic forces and the electromechanical effect of piezoelectricity. We fabricated actuators of two different scales with wing lengths of 17.0 and 32.4 mm and measured their performances in terms of the stroke/pitching angle, average lift force, and average consumed power. The experimental results were in good agreement with the analytical calculation for both types of actuators; the errors in the evaluated characteristics were less than 30%. The results indicated that the analytical model well simulates the actual prototypes.


2020 ◽  
Vol 3 (4) ◽  
pp. 730-765 ◽  
Author(s):  
Kongfa Chen ◽  
San Ping Jiang

Abstract Solid oxide cells (SOCs) are highly efficient and environmentally benign devices that can be used to store renewable electrical energy in the form of fuels such as hydrogen in the solid oxide electrolysis cell mode and regenerate electrical power using stored fuels in the solid oxide fuel cell mode. Despite this, insufficient long-term durability over 5–10 years in terms of lifespan remains a critical issue in the development of reliable SOC technologies in which the surface segregation of cations, particularly strontium (Sr) on oxygen electrodes, plays a critical role in the surface chemistry of oxygen electrodes and is integral to the overall performance and durability of SOCs. Due to this, this review will provide a critical overview of the surface segregation phenomenon, including influential factors, driving forces, reactivity with volatile impurities such as chromium, boron, sulphur and carbon dioxide, interactions at electrode/electrolyte interfaces and influences on the electrochemical performance and stability of SOCs with an emphasis on Sr segregation in widely investigated (La,Sr)MnO3 and (La,Sr)(Co,Fe)O3−δ. In addition, this review will present strategies for the mitigation of Sr surface segregation. Graphic Abstract


Author(s):  
Caiyu Yin ◽  
Zeyu Jin ◽  
Yong Chen ◽  
Hongxing Hua

One-dimensional (1D) analytical model and finite element (FE) simulation are employed to investigate the shock mitigation capability of stepwise graded cellular claddings to underwater blast. To build the analytical model, two types of core configurations are considered: (i) “low → high” with the weakest layer being placed at the impinged end and (ii) the “high → low” configuration. Details of fluid–structure interaction (FSI), response of the graded cladding, and the cavitation phenomenon are thoroughly studied. Then the fidelity of the analytical model is assessed by FE simulations. The results reveal that the analytical model can accurately predict the whole process of such problem. Subsequently, the validated analytical models are used to analyze the influence of density gradient on the shock mitigation capability of cellular claddings in terms of the densification loading, the partial impulse imparted to the cladding, and the work done on the cladding by the external impulse. The results illustrate that the graded claddings perform better than the equivalent uniform case. Compared with the negative density gradient case, the “low → high” configuration with weaker layer being placed at the impinged end is preferable since lower force is transmitted to the protected structure.


Sensors ◽  
2021 ◽  
Vol 21 (20) ◽  
pp. 6759
Author(s):  
Zdenek Machu ◽  
Ondrej Rubes ◽  
Oldrich Sevecek ◽  
Zdenek Hadas

This paper deals with analytical modelling of piezoelectric energy harvesting systems for generating useful electricity from ambient vibrations and comparing the usefulness of materials commonly used in designing such harvesters for energy harvesting applications. The kinetic energy harvesters have the potential to be used as an autonomous source of energy for wireless applications. Here in this paper, the considered energy harvesting device is designed as a piezoelectric cantilever beam with different piezoelectric materials in both bimorph and unimorph configurations. For both these configurations a single degree-of-freedom model of a kinematically excited cantilever with a full and partial electrode length respecting the dimensions of added tip mass is derived. The analytical model is based on Euler-Bernoulli beam theory and its output is successfully verified with available experimental results of piezoelectric energy harvesters in three different configurations. The electrical output of the derived model for the three different materials (PZT-5A, PZZN-PLZT and PVDF) and design configurations is in accordance with lab measurements which are presented in the paper. Therefore, this model can be used for predicting the amount of harvested power in a particular vibratory environment. Finally, the derived analytical model was used to compare the energy harvesting effectiveness of the three considered materials for both simple harmonic excitation and random vibrations of the corresponding harvesters. The comparison revealed that both PZT-5A and PZZN-PLZT are an excellent choice for energy harvesting purposes thanks to high electrical power output, whereas PVDF should be used only for sensing applications due to low harvested electrical power output.


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