scholarly journals Probing the Influence of Multiscale Heterogeneity on Effective Properties of Graphite Electrodes

Author(s):  
Chance Norris ◽  
Mukul Parmananda ◽  
Scott A. Roberts ◽  
Partha P. Mukherjee
2021 ◽  
Author(s):  
Chance A. Norris ◽  
Mukul Parmananda ◽  
Scott Alan Roberts ◽  
Partha P. Mukherjee

Graphite electrodes in the lithium-ion battery exhibit various particle shapes, including spherical and platelet morphologies, which influence structural and electrochemical characteristics. It is well established that porous structures exhibit spatial heterogeneity, and particle morphology can influence transport properties. The impact of particle morphology on the heterogeneity and anisotropy of geometric and transport properties has not been previously studied. This study characterizes the spatial heterogeneities of eighteen graphite electrodes at multiple length scales by calculating and comparing structural anisotropy, geometric quantities, and transport properties (pore-scale tortuosity and electrical conductivity). We found that particle morphology and structural anisotropy play an integral role in determining the spatial heterogeneity of directional tortuosity and its dependency on pore-scale heterogeneity. Our analysis reveals that the magnitude of in-plane and through-plane tortuosity difference influences the multiscale heterogeneity in graphite electrodes.


2010 ◽  
Vol 38 (4) ◽  
pp. 286-307
Author(s):  
Carey F. Childers

Abstract Tires are fabricated using single ply fiber reinforced composite materials, which consist of a set of aligned stiff fibers of steel material embedded in a softer matrix of rubber material. The main goal is to develop a mathematical model to determine the local stress and strain fields for this isotropic fiber and matrix separated by a linearly graded transition zone. This model will then yield expressions for the internal stress and strain fields surrounding a single fiber. The fields will be obtained when radial, axial, and shear loads are applied. The composite is then homogenized to determine its effective mechanical properties—elastic moduli, Poisson ratios, and shear moduli. The model allows for analysis of how composites interact in order to design composites which gain full advantage of their properties.


2015 ◽  
Vol 3 (1) ◽  
pp. 9-18
Author(s):  
Ali J. Jaeel

Chicken manure wastewaters are increasingly being considered a valuable resource of organic compounds. Screened chicken manure was evaluated as a representative solid organic waste. In this study, electricity generation from livestock wastewater (chicken manure) was investigated in a continuous mediator-less horizontal flow microbial fuel cell with graphite electrodes and a selective type of membrane separating the anodic and cathodic compartments of MFC from each other. The performance of MFC was evaluated to livestock wastewater using aged anaerobic sludge. Results revealed that COD and BOD removal efficiencies were up to 88% and 82%, respectively. At an external resistance value of 150 Ω, a maximum power and current densities of 278 m.W/m2 and 683 mA/m2, respectively were obtained, hence MFC utilizing livestock wastewater would be a sustainable and reliable source of bio-energy generation .


Technologies ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 12
Author(s):  
Federico J. Sabina ◽  
Yoanh Espinosa-Almeyda ◽  
Raúl Guinovart-Díaz ◽  
Reinaldo Rodríguez-Ramos ◽  
Héctor Camacho-Montes

The development of micromechanical models to predict the effective properties of multiphase composites is important for the design and optimization of new materials, as well as to improve our understanding about the structure–properties relationship. In this work, the two-scale asymptotic homogenization method (AHM) is implemented to calculate the out-of-plane effective complex-value properties of periodic three-phase elastic fiber-reinforced composites (FRCs) with parallelogram unit cells. Matrix and inclusions materials have complex-valued properties. Closed analytical expressions for the local problems and the out-of-plane shear effective coefficients are given. The solution of the homogenized local problems is found using potential theory. Numerical results are reported and comparisons with data reported in the literature are shown. Good agreements are obtained. In addition, the effects of fiber volume fractions and spatial fiber distribution on the complex effective elastic properties are analyzed. An analysis of the shear effective properties enhancement is also studied for three-phase FRCs.


Author(s):  
Julia Alvarez-Malmagro ◽  
Ana R. Oliveira ◽  
Cristina Gutiérrez-Sánchez ◽  
Beatriz Villajos ◽  
Inês A.C. Pereira ◽  
...  

Batteries ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 34
Author(s):  
Jimmy Aurelio Rosales-Huamani ◽  
Juan Taumaturgo Medina-Collana ◽  
Zoila Margarita Diaz-Cordova ◽  
Jorge Alberto Montaño-Pisfil

The present study aimed to evaluate the factors that influence the formation of sodium hydroxide (NaOH) by means of an electrolytic cell with ion exchange membranes. To achieve this experiment, the NaOH production cell had to be designed and built inexpensively, using graphite electrodes. The operational parameters in our study were: initial NaOH concentration, applied voltage, and temperature. All experiments were carried out using model NaCl solutions with a concentration of 40 g/L for 150 min. The results of the experiment were that the NaOH concentration, conductivity, and pH presented an increasing linear trend with the electrolysis time. Finally, it was possible to obtain the efficiency level of the electric current in our investigation, which was an average of 80.2%, that indicated good performance of the built cell.


Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4344
Author(s):  
Merve Uca ◽  
Ece Eksin ◽  
Yasemin Erac ◽  
Arzum Erdem

Hydroxyapatite nanoparticles (HaP) and ionic liquid (IL) modified pencil graphite electrodes (PGEs) are newly developed in this assay. Electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and cyclic voltammetry (CV) were applied to examine the microscopic and electrochemical characterization of HaP and IL-modified biosensors. The interaction of curcumin with nucleic acids and polymerase chain reaction (PCR) samples was investigated by measuring the changes at the oxidation signals of both curcumin and guanine by differential pulse voltammetry (DPV) technique. The optimization of curcumin concentration, DNA concentration, and the interaction time was performed. The interaction of curcumin with PCR samples was also investigated by gel electrophoresis.


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