Search results for "MODELLING"

Theoretical and experimental study of novel types of solid oxide fuel cell electrodes

2016

Master's thesis Renewable Energy ENE500 - University of Agder 2016 Solid oxide fuel cells (SOFCs) have the potential to become one of the efficient and costeffective system for direct conversion of a wide variety of fuels to electricity. The performance, stability and durability of SOFCs depend strongly on the materials used for the fabrication of electrodes as well as the fabrication process. For anode supported SOFCs, the tape casting method has been the de facto standard for constructing cell components. Furthermore, organic solvents such as ethanol, propanol, terpineol and poly-ethers are generally used in industrial tape casting as the solvent medium to make the chemical slurries out o…

On the Finite Element Modeling of the Lumbar Spine: A Schematic Review

2023

Finite element modelling of the lumbar spine is a challenging problem. Lower back pain is among the most common pathologies in the global populations, owing to which the patient may need to undergo surgery. The latter may differ in nature and complexity because of spinal disease and patient contraindications (i.e., aging). Today, the understanding of spinal column biomechanics may lead to better comprehension of the disease progression as well as to the development of innovative therapeutic strategies. Better insight into the spine’s biomechanics would certainly guarantee an evolution of current device-based treatments. In this setting, the computational approach appears to be a remarkable …

Towards a reduction of greenhouse gas emission from wastewater treatment plants: a new plant wide experimental and modelling approach

2016

The increasing interest in greenhouse gas (GHG) emissions from wastewater treatment plants (WWTPs) has led to the development of new tools for their design and management. Studies about gas emissions show that the sewer collection and the wastewater treatment plant are anthropogenic GHG potential sources, so they contribute to the climate change and air pollution. A wastewater treatment plant receives wastewater from sewers and, while produces treated water for discharge into surface water, emits the three major greenhouse gases, CO2, CH4, and N2O, during the treatment processes, and additional amounts of CO2 and CH4 from the energy demands (Bani Shahabadi et al., 2009). Indeed, energy cons…

On the volumetric response of a compacted clay subjected to wetting and drying cycles

2009

Experimental evidence on the volumetric response of a compacted clay was collected in controlled suction oedometric tests, with the aim to assess the volumetric response of this soil when subjected to wetting and drying cycles. The overall soil behaviour seems mainly to depend on the double structural arrangement observed in the compacted specimens. Selected results are presented and discussed focusing on the influence of the stress history on the volumetric response. Test results are simulated by a double-structure suction-dependent elasto-plastic constitutive model, in which the mechanical response is related to micro and macrostructural deformations and their mutual interactions. The pro…

Design and realization of a DC/DC converter with a partially saturated inductor

2017

DC/DC converters, in some types of applications such as portable equipments, can require more space than it is actually available. The inductor is typically the most bulky element and the possibility to reduce its size can save up to 50% of the converter volume and area [1][2], thus increasing the power density. This reduction, however, comes with nonlinear effects caused by the saturation of the ferromagnetic core. An appropriate modelling of the inductor and of the converter circuit is needed for guaranteeing a good output power quality (Fig. 1). A Boost converter with an inductor in the partially saturated roll-off operating zone was designed and realized to study the behaviour of DC/DC …

Application of computational fluid dynamics technique in electrodialysis/reverse electrodialysis processes

2022

This Chapter treats the application of CFD technique in ED/RED processes. CFD simulations are able to predict flow and mass transfer in channels filled with spacers or membrane profiles, by providing dimensionless correlations useful for process models. At a larger scale, manifolds of the stack and inlet/ outlet zones of the channel can be simulated. Numerical models can include the computation of the electrical potential, thus characterizing the process performance. Direct numerical simulations can elucidate the complex phenomenology of overlimiting transport and of chaotic electrokinetic flows.

Modelació de sedimentadors en plantes de tractament d’aigües residuals. Aplicació al procés de fermentació – elutriació de fangs primaris

2005

La depuració de les aigües residuals requereix la consumació de molts processos de transformació de forma simultània i/o consecutiva, que fan molt difícil el seu estudi. A més, la complexitat dels processos de depuració va en augment no sols per l'aparició de requisits d’abocament cada vegada més exigents, sinó també per les noves tendències cap al desenvolupament sostenible aplicades a aquest procés i centrades fonamentalment en l’estalvi energètic i la recuperació de nutrients de les aigües residuals per millorar el seu cicle de vida. Per aquest motiu, es fa necessari l'ús d'eines de simulació que tinguen en compte tots aquests processos mitjançant un model matemàtic adequat i ajuden a de…

Statistical Modelling and Risk Analysis of Bitcoins Exchange Rate

2018

Master's thesis Business Administration BE501 - University of Agder 2018 Bitcoin is a phenomenon that is new and there is little information on how and why it behaves as volatile as it does. This thesis uses existing data on Bitcoin’s exchange rate to estimate a model that describes the pattern and use it in a financial risk analysis. We also aim to contribute as a foundation for further studies in this field. The statistical properties of the log-return of the exchange rate are analysed and it is deemed to be iid. From the eleven distributional candidates we study is the fitted skew generalised t distribution proven to represent the data best after evaluation by criteria and statistics. Th…

Bioinspired sensors from olfactory proteins

2011

Impact de la flore adventice sur la rétention des pesticides : développement d’un nouvel indicateur pour l’évaluation des systèmes de culture

2016

Weeds are usually considered as harmful for crops but they are essential for biodiversity. Indicators were already developed using the model FLORSYS (Colbach et al., 2014) to evaluate the cropping system in term of harmfullness or benefits related to weed flora. We thus propose a new indicator to evaluate the potential of pesticide retention by weed flora and its impact on pesticide transfer into the environment. The indicator is divided in two parts i) herbicide application efficiency (herbicides interception by weeds), ii) plant uptake for the others pesticides. Several cropping systems have been simulated with the FLORSYS model. Preliminary results have been analyzed using the tree regre…