Search results for " Modeling"

Improved Temperature Coefficient Modeling through the Recombination Parameter $\gamma$

2020

This study presents an injection dependent numerical model relating Shocldey-Read-Hall defect parameters in crystalline silicon with the recombination parameter $\gamma$ . We demonstrate how the model can be used to predict $\gamma$ for various single level defects. Additionally, we show that $\gamma$ can be significantly influenced by the injection level, in contrast to what is commonly assumed. The injection dependence is found to correlate with the temperature sensitivity of the Shocldey-Read-Hall lifetime. Finally, we demonstrate that the model can be used to predict the temperature coefficient of the open circuit voltage without the use of a temperature dependent measurement, enabling …

Supramolecular Packing Drives Morphological Transitions of Charged Surfactant Micelles

2020

Abstract The shape and size of self‐assembled structures upon local organization of their molecular building blocks are hard to predict in the presence of long‐range interactions. Combining small‐angle X‐ray/neutron scattering data, theoretical modelling, and computer simulations, sodium dodecyl sulfate (SDS), over a broad range of concentrations and ionic strengths, was investigated. Computer simulations indicate that micellar shape changes are associated with different binding of the counterions. By employing a toy model based on point charges on a surface, and comparing it to experiments and simulations, it is demonstrated that the observed morphological changes are caused by symmetry br…

Carrier transport mechanism in the SnO(2):F/p-type a-Si:H heterojunction

2011

We characterize SnO(2):F/p-type a-Si:H/Mo structures by current-voltage (I-V) and capacitance-voltage (C-V) measurements at different temperatures to determine the transport mechanism in the SnO2:F/p-type a-Si:H heterojunction. The experimental I-V curves of these structures, almost symmetric around the origin, are ohmic for vertical bar V vertical bar< 0:1 V and have a super-linear behavior (power law) for vertical bar V vertical bar < 0:1 V. The structure can be modeled as two diodes back to back connected so that the main current transport mechanisms are due to the reverse current of the diodes. To explain the measured C-V curves, the capacitance of the heterostructure is modeled as the …

Numerical analysis of light soaking phenomenon in Ruthenium based Dye Sensitized Solar Cells

2017

Dye Sensitized Solar Cells (DSSCs) are widely considered one of the most promising third generation photovoltaic devices, especially thanks to their relatively low cost if compared to conventional solar cells. An interesting phenomenon affecting such devices is the so-called light soaking effect, consisting in the increase of cell main electrical parameters after the exposition to solar light. In this work, starting from the experimental characterization carried out on Ruthenium-based DSSCs, we report on a series of numerical analysis performed to better describe the above-mentioned light soaking effect in order to show the relationship between such phenomenon and the main physical paramete…

Numerical Modeling Approaches of FRCMs/SRG Confined Masonry Columns

2019

The Fabric Reinforced Cementitious Matrices (FRCMs) and Steel Reinforced Grout (SRG) are a promising strengthening solution for existing masonry since inorganic matrix is considerably compatible with historical substrates. The present paper is focused on a Finite Element (FE) analysis of masonry columns confined with FRCM composites developed by Abaqus-code. The masonry columns were modelled using a macro model approach. The model was performed by using the following functions Concrete Damage Plasticity (CDP) and the Plastic (P) in order to describe the constitutive laws of material for masonry columns and external reinforcement, respectively. Typical failures of FRCM-systems are slippage o…

Novel Methodologies to Model Charge Transport in Metal-Air Batteries

2018

Chemical self-organization in self-assembling biomimetic systems

2009

Abstract Far-from-equillibrium oscillating chemical reactions are among the simplest systems showing complex behaviors and emergent properties. This class of reactions is often employed to mimic and understand the mechanisms of a great variety of biological processes. In this context, pattern formation due to the coupling between reaction and transport phenomena represent an active and promising research area. In this paper, we present results coming from experiments where we tried to blend the structural properties of self-assembled matrixes (sodium dodecyl sulphate micelles and phospholipid bilayers) together with the evolutive peculiarities of the Belousov–Zhabotinsky reaction. A series …

The Influence of Surface Roughness on the Structure of Magnetohydrodynamic Flows and Stability of Shallow Water Flows

2008

Promocijas darbā analizēta virsmas negluduma ietekme uz šķidruma plūsmas struktūru magnētiskā laukā un sekla ūdens plūsmas stabilitāti. Promocijas darbā tika aplūkoti šādi modeļi: 1) vadoša šķidruma plūsma ārējā magnētiskā laukā virs dažāda veida negluduma elementiem uz virsmas un 2) sekla ūdens plūsma aiz šķēršļiem. Turklāt ir iegūta magnētiskā lauka struktūra pilnīgi attīstītai plūsmai virs negluduma elementiem. Ir konstruēts analītisks atrisinājums uzdevumam par vadoša šķidruma plūsmu magnētiskā laukā, ja negluduma elementiem ir taisnstūrveida forma. Ir aprēķināti šķidruma plūsmas ātruma un inducētā magnētiskā lauka sadalījumi. Problēmas asimptotisks atrisinājums (elementārās funkcijās) …

A Friendly-Biological Reactor SIMulator (BioReSIM) for studying biological processes in wastewater treatment processes

2014

Biological processes for wastewater treatments are inherently dynamic systems because of the large variations in the influent wastewater flow rate, concentration composition and the adaptive behavior of the involved microorganisms. Moreover, the sludge retention time (SRT) is a critical factor to understand the bioreactor performances when changes in the influent or in the operation conditions take place. Since SRT are usually in the range of 10-30 days, the performance of biological reactors needs a long time to be monitored in a regular laboratory demonstration, limiting the knowledge that can be obtained in the experimental lab practice. In order to overcome this lack, mathematical model…

Modelling, Simulation and Characterization of a Supercapacitor in Automotive Applications

2022

In the energy storage field, supercapacitors (SCs) are gaining more and more attention thanks to features such as high-power density, high life cycles and lack of maintenance. In this article, an improved SC three-branches model which considers the residual charge phenomenon is presented. The procedure to estimate the model parameters and the related experimental set-up are presented. The parameter estimation procedure is repeated for several SCs of the same type. The average parameters are then obtained and used as initial guesses for a recursive least square optimization algorithm, to increase the accuracy of the model. The model of a single SC is then extended to SC banks, testing differ…