20 research outputs found
Simulation and Control of Saltwater Intrusion Through Numerical and Physical Modeling Techniques
Simulation and control of saltwater intrusion based on hydrodynamic dispersion
has been investigated through numerical and physical modeling techniques. In the
mathematical formulation, two equations were derived one for water flow and the other
for solute transport that were coupled through Darcy's velocity and concentration. In the
numerical model formulation, Galerkin finite element approach was applied for deriving
the element matrix equation through quadrilateral elements. To save memory and
computation time, a pointer matrix was used to avoid storage of most of the zeros in the
resulting sparse matrix. The developed model was an efficient and a rather general one
such that the aquifer can be of any types with different boundary conditions and
unlimited number of sources and sinks. For model verification, Henry's problem was
used to compare the model results with previous studies that applied constant and
velocity-dependent dispersion coefficient. The comparison showed a good agreement between the proposed model and the previous ones. Also, for simulation of saltwater
intrusion the computed isochlor contours for the physical model were in good
agreement with the experimental ones
By using the sandbox model and other apparatuses, the average values of
porosity, hydraulic conductivity, dispersion coefficient, and saltwater density were
found to be 0.36, 0.0855 cm/s, 14.34, 10-2 cm2/s, and 1027. 5 kglm3 respectively. These
parameters were used in the numerical simulation. Saltwater intrusion was simulated
experimentally using the physical model under steady and unsteady state conditions
through the measurement of the sodium chloride distribution in the aquifer. According
to physical simulation, the intruded length was changed from 48 cm at steady state to
79 cm at the end of 90 minutes from the steady state during which the freshwater head
was changed every 30 minutes by 0.5 cm from 50 cm to 48.5 cm
Vers des thermodurcissables bio-sourcés : polybenzoxazines à partir de cardanol et composites à base de dialdéhyde cellulose
To reduce the use of finite petroleum-based resources, interest has grown regarding the valorization of renewable resources in chemistry. The work presented in this thesis focused on two bio-based resources: plant oil and lignocellulosic biomass, for the preparation of greener thermoset materials. The first part discussed about polybenzoxazine thermosets. The bio-based content was gradually increased through substitution of petro-based phenol by bio-based cardanol. Cardanol is a natural phenolic derivative extracted from the cashew nutshell liquid. A first study focused on the effect of this aliphatic side chain and how it can tune the reactivity and the final thermo-mechanical properties of the materials. In the following study the reactivity of polymerization of di-phenol monomer was investigated using advanced isoconversional analyses and thermo-mechanical analyses for a better understanding of the polymerization reaction. The second part discussed about the preparation of fully bio-based composites using modified cellulose microfibrils (MFC). Poly(furfuryl alcohol) (PFA) is a bio-based matrix obtained after polymerization of furfruyl alcohol (FA) with maleic anhydride, both obtained from HMF. The PFA properties can be modified by the introduction of cellulose as a filler. MFC was modified by oxidation to lead to reactive dialdehyde functions. By varying the degree of oxidation (DO), the properties of different composites were studied to determine the most adequate DO for the better PFA/MFC compatibility and the most adequate PFA/MFC ratio. Finally, the last study of this thesis focused on the concept of âall cellulose compositesâ (ACC), and particularly how to reduce the moisture sensitivity of these materials. Two different furanic compounds were used as cross-linkers to increase the hydrophobicity: a first compound with one furan ring and a second with two furan rings.Lâutilisation et la valorisation de ressources renouvelables dans le domaine de la chimie connait un intĂ©rĂȘt grandissant pour remplacer les ressources fossiles. Le travail prĂ©sentĂ© dans ce manuscrit de thĂšse est axĂ© sur deux ressources bio-sourcĂ©es utilisĂ©es pour la prĂ©paration de thermodurcissables bio-sourcĂ©s : huile vĂ©gĂ©tale et biomasse lignocellulosique. La premiĂšre partie concerne les polybenzoxazines. A partir dâun monomĂšre Ă base de phĂ©nol, le caractĂšre bio-sourcĂ© est progressivement augmentĂ© par substitution du phenol par du cardanol. Le cardanol est un dĂ©rivĂ© phĂ©nolique bio-sourcĂ© extrait de lâhuile de coque de noix de cajou. Une premiĂšre Ă©tude se concentre sur les effets apportĂ©s par cette chaine alkyle sur la rĂ©activitĂ© et les propriĂ©tĂ©s finales du matĂ©riau. Par la suite, la rĂ©action de polymĂ©risation du composĂ© de rĂ©fĂ©rence est Ă©valuĂ©e par des Ă©tudes cinĂ©tiques, corrĂ©lĂ©es aux analyses thermo-mĂ©caniques pour une meilleure comprĂ©hension de la rĂ©action de polymĂ©risation. La seconde partie de cette thĂšse se concentre sur la prĂ©paration de composites totalement bio-sourcĂ©s, avec des microfibrilles de cellulose (MFC) modifiĂ©es pour obtenir des dialdehyde cellulose (DAC). Le poly(alcool furfruylique) (PFA) est une matrice bio-sourcĂ©e polymĂ©risĂ©e Ă partir dâalcool furfurylique (FA) et dâanhydride malĂ©ique, tous deux obtenus Ă partir du HMF. Les propriĂ©tĂ©s du PFA peuvent ĂȘtre modifiĂ©es en y incorporant un renfort, tel que la cellulose. La modification de MFC par oxydation gĂ©nĂšre des fonctions aldĂ©hydes rĂ©actives qui amĂ©liorent la compatibilitĂ© avec la matrice. Cette Ă©tude compare diffĂ©rents composites prĂ©parĂ©s Ă partir de MFC oxydĂ©e Ă diffĂ©rents DO pour dĂ©terminer quel DO entraine une meilleure compatibilitĂ©. Pour finir, des matĂ©riaux prĂ©parĂ©s Ă partir dâune unique source de cellulose, les « all cellulose composites », ont fait lâobjet de la derniĂšre Ă©tude. Deux diffĂ©rents renforts furaniques ont Ă©tĂ© utilisĂ©s pour contrer les problĂšmes de sensibilitĂ© Ă lâhumiditĂ© de la cellulose, et donc augmenter lâhydrophobicitĂ©
Publishing machine actionable reproducible scholarly knowledge
Scientific research faces many challenges related to the credibility of published results. In essence, there is typically not enough documentation on how experiments are conducted and data is generated. Thus, increasing the reliability of articles through reproducibility will improve the quality of the published scientific literature and others better reliable results. This thesis describes today's problem of the research literature related to non-reproducibility and unstructured data such as weak experiments designs, errors, data dredging and under-specified methods. We suggest a variety of solutions to resolve these problems through linking machine readability with the reproducibility of the information in academic papers. We use therefore a knowledge platform which provides reproducibility on one side and on the other side another platform that ensures the machine actionability of data. Then, we build an integration between them and test it on a selected use case article. After establishing the integration, we obtained, as a result, a reproducible article described in machine-actionable and structured manner. Thereafter, we created a solution that allow every reader to switch between the static and dynamic (reproducible and machine-readable) form of the article. This thesis discusses the benefits and limitations of these observed results and emphasizes the future alternatives
Molecular simulation of aqueous electrolytes in nanoporous carbons : blue energy and water desalination
Lors du mĂ©lange de l'eau douce des riviĂšres avec l'eau salĂ©e de la mer, une quantitĂ© considĂ©rable d'Ă©nergie est dissipĂ©e. Plusieurs procĂ©dĂ©s sont actuellement Ă l'Ă©tude pour parvenir Ă exploiter cette Ă©nergie bleue (Blue Energy). Inversement, la dĂ©salinisation de l'eau de mer pour la production d'eau potable nĂ©cessite de trĂšs grandes quantitĂ©s d'Ă©nergie. Depuis la proposition en 2009 d'une nouvelle approche pour parvenir Ă ces objectifs, grĂące Ă des cycles thermodynamiques reposant sur la charge/dĂ©charge d'Ă©lectrodes Ă forte/faible concentration en sel, expĂ©rimentateurs et ingĂ©nieurs ont essayĂ© d'amĂ©liorer le procĂ©dĂ©. Dans ce contexte, l'utilisation d'Ă©lectrodes nanoporeuses de carbone semble une piste trĂšs prometteuse. Un dĂ©fi de taille reste Ă relever pour dĂ©terminer les quantitĂ©s pertinentes (capacitĂ© Ă©lectrique et quantitĂ© de sel adsorbĂ© en fonction de la composition de l'Ă©lectrolyte et de sa concentration). En effet, les modĂšles traditionnels (Poisson-Boltzmann, etc) ne peuvent pas ĂȘtre utilisĂ©s dans ce cas oĂč les interactions au niveau molĂ©culaire jouent un rĂŽle essentiel. Nous surmontons cette difficultĂ© grĂące aux simulations de dynamique molĂ©culaire, qui permettent Ă©galement de comprendre les mĂ©canismes microscopiques Ă l'origine des propriĂ©tĂ©s observĂ©es. Nous Ă©tudions Ă©galement l'influence de la structure microporeuse de l'Ă©lectrode de carbone ainsi que l'effet de la nature du sel chimique.When fresh river water mixes with salty sea water, a large amount of energy is lost. Conversely, the desalination of seawater for the production of drinking water requires very large amounts of energy. A new approach has been proposed in 2009 to harvest this "blue energy", thanks to the charge/discharge of electrodes in electrolytes with high/low salt concentration. The use of nanoporous carbon electrodes seems promising, but the traditional models (such as Poisson-Boltzmann) used to determine the relevant quantities do not apply in this case where molecular interactions play an essential role. We overcome this difficulty by performing molecular dynamics simulations of nanoporous carbon electrodes in the presence of an aqueous electrolyte. We evaluate the electrical capacity and the amount of ions adsorbed inside the electrodes as a function of the electrolyte composition and its concentration. In addition, these simulations allow us to understand the microscopic mechanisms leading to the storage of the charge, the effect of the structure of the carbon electrode, the salt concentration in the electrolyte and the chemical nature of the salt
Towards greener thermosets : cardanol-based polybenzoxazines and dialdehyde cellulose based composites
Lâutilisation et la valorisation de ressources renouvelables dans le domaine de la chimie connait un intĂ©rĂȘt grandissant pour remplacer les ressources fossiles. Le travail prĂ©sentĂ© dans ce manuscrit de thĂšse est axĂ© sur deux ressources bio-sourcĂ©es utilisĂ©es pour la prĂ©paration de thermodurcissables bio-sourcĂ©s : huile vĂ©gĂ©tale et biomasse lignocellulosique. La premiĂšre partie concerne les polybenzoxazines. A partir dâun monomĂšre Ă base de phĂ©nol, le caractĂšre bio-sourcĂ© est progressivement augmentĂ© par substitution du phenol par du cardanol. Le cardanol est un dĂ©rivĂ© phĂ©nolique bio-sourcĂ© extrait de lâhuile de coque de noix de cajou. Une premiĂšre Ă©tude se concentre sur les effets apportĂ©s par cette chaine alkyle sur la rĂ©activitĂ© et les propriĂ©tĂ©s finales du matĂ©riau. Par la suite, la rĂ©action de polymĂ©risation du composĂ© de rĂ©fĂ©rence est Ă©valuĂ©e par des Ă©tudes cinĂ©tiques, corrĂ©lĂ©es aux analyses thermo-mĂ©caniques pour une meilleure comprĂ©hension de la rĂ©action de polymĂ©risation. La seconde partie de cette thĂšse se concentre sur la prĂ©paration de composites totalement bio-sourcĂ©s, avec des microfibrilles de cellulose (MFC) modifiĂ©es pour obtenir des dialdehyde cellulose (DAC). Le poly(alcool furfruylique) (PFA) est une matrice bio-sourcĂ©e polymĂ©risĂ©e Ă partir dâalcool furfurylique (FA) et dâanhydride malĂ©ique, tous deux obtenus Ă partir du HMF. Les propriĂ©tĂ©s du PFA peuvent ĂȘtre modifiĂ©es en y incorporant un renfort, tel que la cellulose. La modification de MFC par oxydation gĂ©nĂšre des fonctions aldĂ©hydes rĂ©actives qui amĂ©liorent la compatibilitĂ© avec la matrice. Cette Ă©tude compare diffĂ©rents composites prĂ©parĂ©s Ă partir de MFC oxydĂ©e Ă diffĂ©rents DO pour dĂ©terminer quel DO entraine une meilleure compatibilitĂ©. Pour finir, des matĂ©riaux prĂ©parĂ©s Ă partir dâune unique source de cellulose, les « all cellulose composites », ont fait lâobjet de la derniĂšre Ă©tude. Deux diffĂ©rents renforts furaniques ont Ă©tĂ© utilisĂ©s pour contrer les problĂšmes de sensibilitĂ© Ă lâhumiditĂ© de la cellulose, et donc augmenter lâhydrophobicitĂ©.To reduce the use of finite petroleum-based resources, interest has grown regarding the valorization of renewable resources in chemistry. The work presented in this thesis focused on two bio-based resources: plant oil and lignocellulosic biomass, for the preparation of greener thermoset materials. The first part discussed about polybenzoxazine thermosets. The bio-based content was gradually increased through substitution of petro-based phenol by bio-based cardanol. Cardanol is a natural phenolic derivative extracted from the cashew nutshell liquid. A first study focused on the effect of this aliphatic side chain and how it can tune the reactivity and the final thermo-mechanical properties of the materials. In the following study the reactivity of polymerization of di-phenol monomer was investigated using advanced isoconversional analyses and thermo-mechanical analyses for a better understanding of the polymerization reaction. The second part discussed about the preparation of fully bio-based composites using modified cellulose microfibrils (MFC). Poly(furfuryl alcohol) (PFA) is a bio-based matrix obtained after polymerization of furfruyl alcohol (FA) with maleic anhydride, both obtained from HMF. The PFA properties can be modified by the introduction of cellulose as a filler. MFC was modified by oxidation to lead to reactive dialdehyde functions. By varying the degree of oxidation (DO), the properties of different composites were studied to determine the most adequate DO for the better PFA/MFC compatibility and the most adequate PFA/MFC ratio. Finally, the last study of this thesis focused on the concept of âall cellulose compositesâ (ACC), and particularly how to reduce the moisture sensitivity of these materials. Two different furanic compounds were used as cross-linkers to increase the hydrophobicity: a first compound with one furan ring and a second with two furan rings
Simulation moléculaire d'électrolytes aqueux dans les carbones nanoporeux : Energie bleue et désalinisation de l'eau
When fresh river water mixes with salty sea water, a large amount of energy is lost. Conversely, the desalination of seawater for the production of drinking water requires very large amounts of energy. A new approach has been proposed in 2009 to harvest this "blue energy", thanks to the charge/discharge of electrodes in electrolytes with high/low salt concentration. The use of nanoporous carbon electrodes seems promising, but the traditional models (such as Poisson-Boltzmann) used to determine the relevant quantities do not apply in this case where molecular interactions play an essential role. We overcome this difficulty by performing molecular dynamics simulations of nanoporous carbon electrodes in the presence of an aqueous electrolyte. We evaluate the electrical capacity and the amount of ions adsorbed inside the electrodes as a function of the electrolyte composition and its concentration. In addition, these simulations allow us to understand the microscopic mechanisms leading to the storage of the charge, the effect of the structure of the carbon electrode, the salt concentration in the electrolyte and the chemical nature of the salt.Lors du mĂ©lange de l'eau douce des riviĂšres avec l'eau salĂ©e de la mer, une quantitĂ© considĂ©rable d'Ă©nergie est dissipĂ©e. Plusieurs procĂ©dĂ©s sont actuellement Ă l'Ă©tude pour parvenir Ă exploiter cette Ă©nergie bleue (Blue Energy). Inversement, la dĂ©salinisation de l'eau de mer pour la production d'eau potable nĂ©cessite de trĂšs grandes quantitĂ©s d'Ă©nergie. Depuis la proposition en 2009 d'une nouvelle approche pour parvenir Ă ces objectifs, grĂące Ă des cycles thermodynamiques reposant sur la charge/dĂ©charge d'Ă©lectrodes Ă forte/faible concentration en sel, expĂ©rimentateurs et ingĂ©nieurs ont essayĂ© d'amĂ©liorer le procĂ©dĂ©. Dans ce contexte, l'utilisation d'Ă©lectrodes nanoporeuses de carbone semble une piste trĂšs prometteuse. Un dĂ©fi de taille reste Ă relever pour dĂ©terminer les quantitĂ©s pertinentes (capacitĂ© Ă©lectrique et quantitĂ© de sel adsorbĂ© en fonction de la composition de l'Ă©lectrolyte et de sa concentration). En effet, les modĂšles traditionnels (Poisson-Boltzmann, etc) ne peuvent pas ĂȘtre utilisĂ©s dans ce cas oĂč les interactions au niveau molĂ©culaire jouent un rĂŽle essentiel. Nous surmontons cette difficultĂ© grĂące aux simulations de dynamique molĂ©culaire, qui permettent Ă©galement de comprendre les mĂ©canismes microscopiques Ă l'origine des propriĂ©tĂ©s observĂ©es. Nous Ă©tudions Ă©galement l'influence de la structure microporeuse de l'Ă©lectrode de carbone ainsi que l'effet de la nature du sel chimique
Simulation moléculaire d'électrolytes aqueux dans les carbones nanoporeux : énergie bleue et désalinisation de l'eau
When fresh river water mixes with salty sea water, a large amount of energy is lost. Conversely, the desalination of seawater for the production of drinking water requires very large amounts of energy. A new approach has been proposed in 2009 to harvest this "blue energy", thanks to the charge/discharge of electrodes in electrolytes with high/low salt concentration. The use of nanoporous carbon electrodes seems promising, but the traditional models (such as Poisson-Boltzmann) used to determine the relevant quantities do not apply in this case where molecular interactions play an essential role. We overcome this difficulty by performing molecular dynamics simulations of nanoporous carbon electrodes in the presence of an aqueous electrolyte. We evaluate the electrical capacity and the amount of ions adsorbed inside the electrodes as a function of the electrolyte composition and its concentration. In addition, these simulations allow us to understand the microscopic mechanisms leading to the storage of the charge, the effect of the structure of the carbon electrode, the salt concentration in the electrolyte and the chemical nature of the salt.Lors du mĂ©lange de l'eau douce des riviĂšres avec l'eau salĂ©e de la mer, une quantitĂ© considĂ©rable d'Ă©nergie est dissipĂ©e. Plusieurs procĂ©dĂ©s sont actuellement Ă l'Ă©tude pour parvenir Ă exploiter cette Ă©nergie bleue (Blue Energy). Inversement, la dĂ©salinisation de l'eau de mer pour la production d'eau potable nĂ©cessite de trĂšs grandes quantitĂ©s d'Ă©nergie. Depuis la proposition en 2009 d'une nouvelle approche pour parvenir Ă ces objectifs, grĂące Ă des cycles thermodynamiques reposant sur la charge/dĂ©charge d'Ă©lectrodes Ă forte/faible concentration en sel, expĂ©rimentateurs et ingĂ©nieurs ont essayĂ© d'amĂ©liorer le procĂ©dĂ©. Dans ce contexte, l'utilisation d'Ă©lectrodes nanoporeuses de carbone semble une piste trĂšs prometteuse. Un dĂ©fi de taille reste Ă relever pour dĂ©terminer les quantitĂ©s pertinentes (capacitĂ© Ă©lectrique et quantitĂ© de sel adsorbĂ© en fonction de la composition de l'Ă©lectrolyte et de sa concentration). En effet, les modĂšles traditionnels (Poisson-Boltzmann, etc) ne peuvent pas ĂȘtre utilisĂ©s dans ce cas oĂč les interactions au niveau molĂ©culaire jouent un rĂŽle essentiel. Nous surmontons cette difficultĂ© grĂące aux simulations de dynamique molĂ©culaire, qui permettent Ă©galement de comprendre les mĂ©canismes microscopiques Ă l'origine des propriĂ©tĂ©s observĂ©es. Nous Ă©tudions Ă©galement l'influence de la structure microporeuse de l'Ă©lectrode de carbone ainsi que l'effet de la nature du sel chimique
Does integrated building information modelling support construction supply chains? A systematic review of theories, methods and actors
Building information modelling (BIM) and supply chain management (SCM) both aim to integrate data to enhance construction efficiency. While BIM holds transformative potential, current research mainly focuses on individual supply chain actors. This study aims to evaluate BIM/SCM literature, categorise research methods and theoretical lenses, identify insights for diverse supply chain actors, and propose future research directions. Through a systematic literature review (SLR), 56 relevant published studies were identified and analysed. Findings reveal that 17 studies explicitly used theoretical lenses. Most studies employed case studies and mixed methods, with a focus on individual actors. This suggests that BIM-supply chain research is still evolving, emphasising the need for further research to understand BIM adoption across the whole supply chain as one system. The study's originality lies in systematically analysing BIM-supply chain interfaces, providing a unique perspective on research methods, theoretical frameworks, and supply chain actors, which can guide future research
Progressive substitution of phenol by a bio-based analogue for the preparation of polybenzoxazines thermosets
International audienc