Dissertations / Theses on the topic 'Liquid LIBS'

Aujourd’hui, le principal facteur limitant le photovoltaïque est le prix élevé du kWh produit par les modules PV. Pour faire face à cette difficulté, les recherches actuelles se concentrent autour de plusieurs leviers et solutions alternatives : la réduction du coût énergétique avec notamment la réduction du coût de la matière première, qui consiste en la diminution de l’épaisseur des wafers de silicium, ou encore l’élaboration de cellules en couches minces de silicium. Ce dernier procédé a pour but de s’affranchir de l’étape de sciage des blocs de silicium, nécessaire pour la réalisation de plaquette photovoltaïque de faible épaisseur. C’est cette dernière approche qui nous a conduits à proposer un procédé d’élaboration de couches minces à l’aide d’un plasma et du chauffage du substrat. Par ailleurs, quel que soit le procédé choisi pour atteindre la cristallinité et la pureté exigées pour le grade solaire, il est nécessaire de disposer de technique analytique multiélémentaire pour contrôler l’évolution de la pureté en fonction des paramètres. La LIBS que nous avons développée au laboratoire offre l’opportunité de répondre à ces attentes : très basses limites de détection tout en permettant un suivi en ligne du silicium à l’état solide ou en fusion
Today, the main limiting factor of PV is the high price of electricity production by the PV modules. To cope with this difficulty, current researches focus on several ways and alternatives solutions: reducing energy costs including reducing the cost of the raw material, which consists in reducing the thickness of silicon wafers or in the development of cells in thin silicon layers. The latter process is intended to overcome the sawing step of silicon ingots which is necessary for the realization of photovoltaic wafer. It is this very approach that led us to develop a method to prepare thin films by using plasma and heating the substrate. Moreover, whatever the method chosen to achieve the required crystallinity and purity for solar grade, it is necessary to have a multi-elements analytical technique to control the evolution of purity. In our laboratory, we have developed LIBS which can meet these expectations, i-e very low detection limits while allowing online tracking of silicon in solid or liquid state

Plus de 50 % des handicaps neurodéveloppementaux sont dus à une exposition périnatale à des stress toxiques ou oxydants. Comprendre comment le cerveau est protégé au cours du développement périnatal et pourquoi ses mécanismes de défense sont dépassés lorsque l’enfant est soumis à un stress important est donc crucial. La barrière sang – liquide céphalorachidien (LCR), localisée au niveau des plexus choroïdes, présente une capacité de détoxification élevée et pourrait donc avoir un rôle prépondérant dans la protection du cerveau au stade périnatal. Nous avons étudié la capacité de plusieurs enzymes choroïdiennes à protéger l'environnement liquidien cérébral pendant la période postnatale chez le rat, et évalué si leurs activités pouvaient être induites par la voie du nuclear factor erythroid-2-related factor 2 (Nrf2). Le facteur Nrf2 peut en effet moduler l’expression de différents gènes codant pour des enzymes de détoxification. Nous avons montré que les glutathion transférases (Gst) et les glutathion peroxydases (Gpx), intervenant respectivement dans l’inactivation des molécules toxiques et dans la régulation du stress oxydant, présentaient des activités choroïdiennes élevées pendant la période postnatale, et avons caractérisé fonctionnellement leur capacités de neuroprotection. Le traitement des ratons avec du diméthylfumarate (DMF), inducteur de la voie Nrf2, induit la migration nucléaire de Nrf2, augmente l’activité choroïdienne Gst, et réduit de 40 % le passage cérébral de toxiques substrats des Gst. Ces données montrent la capacité neuroprotectrice précoce des plexus choroïdes, et indique qu’elle peut être induite pharmacologiquement
More than 50 % of intellectual or sensory-motor deficits in children are due to perinatal exposure to oxidative stress or toxicants. Understanding brain protection mechanisms during development is crucial to design therapeutic strategies to address these disabilitating disorders. The choroid plexuses, forming an interface between the blood and the cerebrospinal fluid (CSF), have a high detoxifying capacity, suggesting their involvement in neuroprotection. The nuclear factor erythroid-2-related factor 2 (Nrf2) pathway can modulate the expression of several genes encoding for antioxidant proteins and detoxifying enzymes. We studied the ability of several choroidal enzyme families to protect the brain fluid environment during the postnatal period in rat and explored whether this protection can be enhanced by Nrf2 pathway. We focused on glutathione transferases (Gsts), which conjugate toxic compounds to glutathione, and glutathione peroxidases (Gpxs), which detoxify reactive oxygen species. Gst and Gpx specific activities were high during the postnatal period in choroid plexuses compared to the cerebral cortex, and their neuroprotective functions were efficient. The Nrf2 factor is expressed in choroid plexuses during the perinatal period. Treatment of rat pups with Nrf2 activator dimethylfumarate induced Nrf2 nuclear translocation and increased Gst activities in choroid plexus tissues. The dimethylfumarate treatment resulted in a large decrease of the blood-to-CSF permeability of a prototypical Gst substrate. These data substantiate the early neuroprotective functions of choroid plexuses, which can be enhanced upon treatment with clinically used pharmacological compounds

Cette etude s'inscrit dans le cadre des recherches menees sur les effets des chocs sur les milieux liquides. Elle a pour objectif l'approche plus particuliere des phenomenes lies au passage d'une onde de choc au travers de l'interface liquide-air. Pour atteindre cet objectif nous avons ete conduits a adopter une demarche cognitive permettant d'apprecier et de decrire les phenomenes macroscopiques (bulle, dome, gerbe. . . ) lies a la detonation, pour nous orienter vers l'etude des effets plus precoces et plus difficilement observables (cavitation, jets. . . ). Une des caracteristiques de notre travail reside dans l'exploitation d'un ensemble des moyens et de techniques de mesure (mesures de pression, cinematographie ultra-rapide, microholographie, strioscopie, tomographie, laser. . . ). Les resultats ainsi obtenus sont correles avec une premiere approche theorique et permettent parallelement de verifier les orientations plus personnelles. Ils precisent les relations entre les phenomenes subaquatiques telles que la cavitation, se concretisant par des effets a l'interface, sa decohesion en gouttelettes par des jets se fragmentant dans l'air. Cette approche a ete modelisee par une simulation numerique

Content: Nowadays, tannery pollution is of great concern worldwide. The unhairing and fiber bundle-opening processes contribute the majority of the pollution by the use of sodium sulfide and calcium hydroxide, which were proposed to be replaced by neutral protease combined with (potassium chloride) KCl, (lithium bromide)LiBr/1-allyl-3-methylimidazolium chloride([AMIm]Cl) in the present work. Proper amount of KCl can speed up the unhairing with the grain not destroyed by the neutral protease. Four methods for unhairing and fiber bundle-opening were used as follows: 1. Two steps in different floats as KCl/neutral protease unhairing, followed by LiBr/[AMIm]Cl for fiber bundle-opening; 2. Two steps in different floats as neutral protease unhairing, followed by LiBr/[AMIm]Cl for fiber bundle-opening; 3. One step in the same float as neutral protease for unhairing firstly and then LiBr/[AMIm]Cl for fiber bundle-opening. 4. One step in the same float as neutral protease/KCl for unhairing firstly and then LiBr/[AMIm]Cl for fiber bundle-opening. It was found that using neutral protease/KCl solution for unhairing and LiBr/[AMIm]Cl solution for fiber bundle-opening is the best in fiber bundle-opening at the liming process. Besides, all the methods used here are better than the traditional liming processes (C) from viewpoints of unhairing and fiber bundleopening. Take-Away: 1. The addition of potassium chloride can improve the stability of neutral protease solution. 2. The catalytic efficiency of the enzyme was improved because of adding potassium chloride can enhance the contact rate of neutral protease with substrate. 3. Ionic liquids have less hydrolysis of collagen and larger dissolution of polysaccharides.

La contamination par métaux des eaux est un enjeu de santé publique important. Des contrôles et traitements de plus en plus drastiques sont ainsi effectués sur les eux destinés à la consommation humaine. Il est indispensable, pour cela, de posséder des outils analytiques fiables et sensibles, adaptés aux réglementations existantes et suffisamment souples d'utilisation. La technique de " Laser Induced Breakdown Spectroscopy " (LIBS), ayant fait ses preuves pour l'analyse des solides, y compris dans les explorations exo-terrestres, présente des avantages très intéressants pour les liquides dont, par exemple, sont caractère multi-élémentaire et la possibilité des mesures in-situ de la contamination des eaux par métaux.Un première volet d'étude de ce travail de thèse à permis d'étudier les potentialités de la spectroscopie sur plasma induit par laser (LIBS) pour l'analyse des métaux dissous ou en suspensions dans les eaux. Etude qu'a permis de constater un effet important lié à la taille des particules lors de l'analyse de suspensions. Un deuxième volet consisté à regarder les effets de matrice organique représentée par un acide humique et ceux des minéraux naturels représentés par la bentonite et des particules d'alumine. Effets matrice qu'ont étais corriges par une normalisation par étalon interne.

No atual período de incertezas na geração e transmissão de energia elétrica no Brasil, a utilização dos sistemas de cogeração com uso de gás natural, tornou-se uma grande oportunidade econômica, estratégica e tecnológica, para as pequenas e médias empresas, considerando a extensão e perspectivas de expansão da rede de distribuição de gás natural. Uma empresa farmacêutica para se manter competitiva e reduzir o impacto dos custos indiretos em seus produtos, necessitava aumentar sua linha de injetáveis, produzindo no Brasil alguns medicamentos que até então eram importados de filiais em outros países e para que isto fosse possível, teria de investir na construção de novos laboratórios, compra de equipamentos, aumento de utilidades para sua fabricação como vapor de água para injetáveis, sistema de HVAC para salas limpas, o que levaria a um aumento de consumo de energia, vapor, água de refrigeração. Este investimento inviabilizaria a produção desta nova linha de produtos, pois tanto o custo do investimento em novas centrais de utilidades, quanto mais o custo desta geração e sua manutenção, decretariam um fim para a esta empreita. Neste trabalho, apresentou-se uma alternativa como solução para viabilizar esta instalação, trocando-se os chillers convencionais por um chiller de absorção, que alem de consumir pouca energia elétrica utilizando a troca térmica entre brometo de lítio e vapor para gerar água de resfriamento para o sistema de ar condicionado, o sistema proposto proporcionou um aumento de fornecimento de vapor não só para alimentar o sistema de HVAC como para a produção da fabrica, anexo a esta caldeira de recuperação é proposto a instalação de uma turbina á gás com condições suficientes de gerar energia elétrica para todo o site e ainda ter condições de negociar o excedente de energia para ser vendido para a concessionária. O resultado deste sistema proposto demonstrou uma excelente eficiência, frente ao sistema convencional, o que tecnicamente se apresentou como muito viável.
In the current period of uncertainty in the generation and transmission of electric energy in Brazil, the use of cogeneration systems using natural gas, has become a great economic opportunity, strategic and technology for small and medium enterprises, considering the extent and prospects for expansion of the distribution of natural gas. A pharmaceutical company to remain competitive and reduce the impact of indirect costs in their products, needed to increase its line of injectables, producing here in Brazil some drugs that were previously imported from subsidiaries in other countries and to make this possible, would invest in building new laboratories, purchase equipment, increase of utilities for its manufacture steam as water for injection, the HVAC system for clean rooms, leading to an increased consumption of energy, steam, cooling water. This investment would make impracticable the production of this new line of products, therefore not only the cost of the investment in new central offices of utilities, the more the cost of this generation of utilities and its maintenance, would decree an end for the this take over on a contract basis. In this work, presented as an alternative solution to enable this facility, exchanging conventional chillers for an absorption chiller, which besides consume little electricity using the heat exchange between lithium bromide to generate steam and cooling water for the air conditioning system, the proposed system provided an increased supply of steam to feed not only the HVAC system for the production of manufactures, attached to this recovery boiler is proposed to install a gas turbine with sufficient conditions generate electricity for the entire site and still be able to trade the surplus energy to be sold to the utility. The result of this proposed system showed an excellent efficiency, compared to the conventional system, which technically is presented as very viable.

Le tritium et le carbone 14 sont les principaux contributeurs de l’activité dans les effluents liquides de CNPE (centrale nucléaire de production d’électricité). Ces derniers sont produits principalement dans le circuit primaire par activation neutronique. L’impact dosimétrique dépend des formes sous lesquelles se trouvent le tritium et le carbone 14. L’étude bibliographique a permis d’identifier les molécules organiques susceptibles d’être présentes au sein des effluents liquides. Elles proviennent du conditionnement des différents circuits et de leurs produits de dégradation. Ces molécules transitant par les effluents liquides, elles sont donc susceptibles d’être radiomarquées du fait de la présence avérée de tritium et carbone 14. L’objectif de la thèse est d’identifier les différentes formes organiques présentes et leur potentiel radiomarquage avec le tritium et le carbone 14. L’approche utilisée pour répondre à cette problématique est divisée en deux étapes clés. La première concerne l’identification et la quantification des molécules organiques (par des techniques chromatographiques). La seconde est relative à la quantification des différentes formes (organique et inorganique) du tritium et du carbone 14. Cette dernière est un réel challenge compte tenu de la composition radiologique des effluents. En effet, la fraction organique marquée potentiellement attendue est très faible (1-3%) et la séparation des formes organiques et de la matière organique soluble est délicate. Une étape de séparation est donc nécessaire avant quantification des fractions (organique et inorganique) par scintillation liquide
Tritium and carbon 14, produced in the primary coolant by neutron activation, are the main contributors to the radioactivity released in the discharges of nuclear power plants. The dosimetric impact depends on the form in which tritium and carbon 14 are found. The bibliographic study identified the organic molecules likely to be present in liquid effluents. They come from the conditioning of the various circuits and their degradation products. These molecules are transiting through liquid effluents and are therefore likely to be radiolabelled due to the proven presence of tritium and carbon-14. The objective of the thesis is to identify the different organic forms present and their potential radiolabelling with tritium and carbon 14. The approach used to address this issue is divided into two key stages. The first concerns the identification and quantification of organic molecules (by chromatographic techniques). The second is related to the quantification of the different forms (organic and inorganic) of tritium and carbon 14. The latter is a real challenge given the radiological composition of the effluents. Indeed, the potentially expected labelled organic fraction is very small (1-3%) and the separation of organic forms and the soluble organic matter is delicate. A separation step is therefore necessary before quantification of the fractions (organic and inorganic) by liquid scintillation

Thesis (Honors paper)--Florida State University, 2010.
Advisor: Dr. Subramanian Ramakrishnan, Florida State University, College of Engineering, Dept. of Chemical & Biomedical Engineering. Includes bibliographical references.

The present thesis deals with the beneficial influence of nanostructuring on electrochemical performance of certain promising electrode and electrolyte materials for lithium-ion batteries (LIBs). Electrochemical performances of chosen electrodes and electrolytes have been presented in a systematic and detailed manner via studies related to both transport and lithium storage. Titanium dioxide (TiO2) or titania, a promising non-carbonaceous anode material for LIBs was chosen for the study. As part of the study, variety of nanostructured titania were synthesized. In general, all materials exhibited high lithium storage ( theoretical value for lithium storage in titania) and some of them showed exemplary rate capability, typically desired for modern lithium-ion batteries. Studies related to performance of these materials and mechanistics of lithium storage and kinetics are presented in Chapters 2-5. “Soggy sand” electrolyte, a promising soft matter electrolyte for LIBs was studied on the electrolyte side. Ion transport, mechanical strength and electrochemical properties of “soggy sand” electrolytes synthesized via dispersion of various surface chemically functionalized silica particles dispersed in model as well as LIB relevant electrolytes were studied in this thesis. Extensive physico-chemical and battery performance studies of “soggy sand” electrolytes are discussed in Chapters 6-8. A brief discussion of the contents and highlights of the individual chapters are described below: Chapter 1 briefly discusses the importance of electrochemical power sources as a viable green alternative to the combustion engine. Various facets of rechargeable LIBs, one of the most important electrochemical storage devices, are presented following the general discussion on electrochemical power devices. The importance of nanostructuring of electrodes with special emphasis on anodes for high lithium storage capacities and rate capabilities are also discussed in the opening chapter. The various advantages and disadvantages of the most commonly used electrolytes in LIB i.e. the liquid electrolytes are also discussed in Chapter 1. Suggestions for improvement of the physico-chemical properties of liquid electrolytes especially via nanostructuring (demonstrated via dispersions of fine oxide particles in liquid electrolytes in Chapters 6-8) using the concept of Heterogeneous doping are discussed in detail. A brief description on the importance of rheology for comprehension of soft matter microstructure is also provided in this chapter. Chapter 2 discusses composite of anatase titania (TiO2) nanospheres and carbon grown and self-assembled into micron-sized mesoporous spheres via a solvothermal synthesis route as prospective anode for rechargeable lithium-ion battery. The morphology and carbon content and hence the electrochemical performance are observed to be significantly influenced by the synthesis parameters. Synthesis conditions resulting in a mesoporous arrangement of an optimized amount of carbon and TiO2 exhibited the best lithium battery performance. The first discharge cycle capacity of carbon-titania mesoporous spheres (solvothermal reaction at 150 oC at 6 h, calcination at 500 oC under air, BET surface area 80 m2g-1) was 334 mAhg-1 (approximately 1 Li) at current rate of 66 mAg-1. High storage capacity and good cyclability is attributed to the nanostructuring (i.e. mesoporosity) of TiO2 as well as due to formation of a percolation network of carbon around the TiO2 nanoparticles. The micron-sized mesoporous spheres of carbon-titania composite nanoparticles also show good rate cyclability in the range (0.066-6.67) Ag-1. The electrochemical performance of the mesoporous carbon-TiO2 spheres has been compared with nonporous TiO2 spheres, normal mesoporous TiO2 and bulk TiO2. Implications of nanostructuring and conductive carbon interface on lithium insertion/removal capacity and insertion kinetics in nanoparticles of anatase polymorph of titania is discussed in Chapter 3. Sol-gel synthesized nanoparticles of titania (particle size ~ 6 nm) were hydrothermally coated ex situ with a thin layer of amorphous carbon (layer thickness: 2-5 nm) and calcined at a temperature much higher than the sol-gel synthesis temperature. The carbon-titania composite particles (resulting size  10 nm) displayed immensely superior cyclability and rate capability (higher current rates  4 Ag-1) compared to unmodified calcined anatase titania. The conductive carbon interface around titania nanocrystals enhances the electronic conductivity and inhibits crystallite growth during electrochemical insertion/removal thus preventing detrimental kinetic effects observed in case of un-modified anatase titania. The carbon coating of the nanoparticles also stabilized the titania crystallographic structure via reduction in the accessibility of lithium ions to the trapping sites. This resulted in decrease in the irreversible capacity observed in case of nanoparticles without any carbon coating. Chapter 4 discusses the morphology and electrochemical performance of mixed crystallographic phase titania nanotubes and nanosheets for prospective application as anode in rechargeable lithium-ion batteries. Hydrothermally grown nanotubes/nanosheets of titania (TiO2) and carbon/silver-titania (C/Ag-TiO2) comprise a mixture of both anatase and TiO2(B) crystallographic phases. The first cycle capacity (at current rate = 10 mAg-1) for bare TiO2 nanotubes was 355 mAhg-1 (approximately 1.06 Li), which is higher than both the theoretical capacity (335 mAhg-1) as well as reported values for pure anatase and TiO2(B) nanotubes. Higher capacity is attributed to a combination of presence of mixed crystallographic phases of titania as well as trivial size effects. The surface area of bare TiO2 nanotubes was very high being equal to 340 m2g-1. Surface modification of the TiO2 nanotubes via amorphous carbon and Ag nanoparticles resulted in significant improvement in battery performance. The first cycle irreversible capacity loss can be minimized via effective coating of the surface. Carbon coated TiO2 nanotubes showed superior performance than Ag nanoparticle coated TiO2 nanotubes in terms of long term cyclability. Unlike Ag nanoparticles which are randomly distributed over the TiO2 nanotubes, the effective homogeneous carbon coating forms an efficient percolation network for the conducting species thus exhibiting better battery performance. The C-TiO2 and Ag-TiO2 nanotubes showed a better rate capability i.e. higher capacities compared to bare TiO2 nanotubes in the current range 0.055-2 Ag-1. Although titania nanosheets retains mixed crystallographic phases, the lithium battery performance (first cycle capacity = 225 mAhg-1) is poor compared to TiO2 nanotubes. It is attributed to lower surface area (22 m2g-1) which resulted in lesser electrode/electrolyte contact area and inefficient transport pathways for Li+ and e-. Implications of iron on electrochemical lithium insertion/removal capacity of iron (Fe3+) doped anatase TiO2 is discussed in Chapter 5. Iron doped anatase TiO2 nanoparticles with different doping concentrations were synthesized by simple sol-gel method. The electrochemistry of anatase TiO2 is observed to be a strong function of concentration of iron (Fe3+). A high 1st cycle discharge capacity of 704 mAhg−1 (2.1 mol of Li) and 272 mAhg−1 (0.81 mol of Li) at the 30th discharge cycle with Coulombic efficiency greater than 96% has been observed for 5% iron (Fe3+) doped TiO2 at a current density of 75 mAg−1. Additional increase in the iron (Fe3+) concentrations deteriorates the lithium storage of TiO2. An improvement in lithium storage of more than 50% is noticed for 5% iron (Fe3+) doped TiO2 compared to pure anatase TiO2 which shows an initial discharge capacity of 279 mAhg−1. The anomalous lithium storage behavior in all the iron (Fe3+) doped TiO2 has been accounted, in addition to homogeneous Li insertion in the octahedral sites, on the basis of formation of metallic Fe and Li2O during initial lithiation process and subsequent heterogeneous interfacial storage between Fe and Li2O interface. Chapter 6 discusses in a systematic manner the crucial role of oxide surface chemical composition on ion transport in “soggy sand” electrolytes. A “soggy sand” electrolytic system comprising of aerosil silica functionalized with various hydrophilic and hydrophobic moeities dispersed in lithium perchlorate ethylene glycol solution ( = 37.7) was used for the study. Detailed rheology studies show that the attractive particle network in case of the composite with unmodified aerosil silica (with surface silanol groups) is most favorable for percolation in ionic conductivity as well as rendering the composite with beneficial elastic mechanical properties. Though weaker in strength compared to the composite with unmodified aerosil particles, attractive particle networks are also observed in composites of aerosil particles with surfaces partially substituted with hydrophobic groups. However, ionic conductivity is observed to be dependent on the size of the hydrophobic moiety. No spanning attractive particle network was formed for aerosil particles with surfaces modified with stronger hydrophilic groups (than silanol) and as a result no percolation in ionic conductivity was observed. The composite with hydrophilic particles was a sol contrary to gels obtained in case of unmodified aerosil and partially substituted with hydrophobic groups. Chapter 7 also discusses the influence of oxide surface chemical composition but additionally the role of solvent on ion solvation and ion transport of “soggy sand” electrolytes. Compared to the liquid electrolyte in Chapter 6, a lower dielectric constant liquid electrolyte was employed for the study in this chapter. A “soggy sand” electrolyte system comprising of dispersions of hydrophilic/hydrophobic functionalized aerosil silica in lithium perchlorate-methoxy polyethylene glycol solution ( = 10.9) was employed for the study. Static and dynamic rheology measurements again showed formation of an attractive particle network in case of the composite with unmodified aerosil silica (i.e. with surface silanol groups) as well as composites with hydrophobic alkane groups. While particle network in the composite with hydrophilic aerosil silica (unmodified) were due to hydrogen bonding, hydrophobic aerosil silica particles were held together via van der Waals forces. The network strength in the latter case (i.e. for hydrophobic composites) were weaker compared with the composite with unmodified aerosil silica. Both unmodified silica as well as hydrophobic silica composites displayed solid-like mechanical strength. However, this time around no enhancement in ionic conductivity compared to the liquid electrolyte was observed in case of the unmodified silica. This is attributed to the existence of a very strong particle network which leads to the “expulsion” of all conducting entities from the interfacial region between adjacent particles. The ionic conductivity for composites with hydrophobic aerosil particles displayed ionic conductivity as a function of the size of the hydrophobic chemical moiety. No spanning attractive particle network was observed for aerosil particles with surfaces modified with stronger hydrophilic groups (than silanol). The composite resembled a sol and no percolation in ionic conductivity was observed. Chapter 8 describes the influence of dispersion of uniformly sized mono-functional or bi-functional (“Janus”) particles on ionic conductivity in lithium battery solutions and it’s implications on battery performance. Mono-functionalized (hydrophilic or hydrophobic) and bi-functionalized Janus (hydrophilic and hydrophobic) particles form physical gels of varying strength over a wide range of concentration (0.1    0.4; , oxide volume fraction). While the composites with mono-functionalized particles display shear thinning typical of gels (due to gradual breaking up spanning particle network held together by hydrogen/van der Walls force), the bi-functionalized “Janus” particles exhibit both complementary properties of gel and sol. The latter observation is interpreted in terms of existence of both hydrogen and van der Waals force arising out of the particle arrangement which get perturbed under the influence of external shear. Composites with homogeneous hydrophilic surface group show the highest ionic conductivity whereas the homogeneous hydrophobic surfaces exhibit superior electrode/electrolyte interface stability and battery cyclability. The Janus particles did not show any enhancement in ionic conductivity however, battery performance is highly satisfactory taking intermediate values between the homogeneously functionalized hydrophilic and hydrophobic particle composites.

L’élevage des porcs représente une source importante de déversement d’antibiotiques dans l’environnement par l’intermédiaire de l’épandage du lisier qui contient une grande quantité de ces molécules sur les champs agricoles. Il a été prouvé que ces molécules biologiquement actives peuvent avoir un impact toxique sur l’écosystème. Par ailleurs, elles sont aussi suspectées d’engendrer des problèmes sanitaires et de contribuer à la résistance bactérienne pouvant mener à des infections difficilement traitables chez les humains. Le contrôle de ces substances dans l’environnement est donc nécessaire. De nombreuses méthodes analytiques sont proposées dans la littérature scientifique pour recenser ces composés dans plusieurs types de matrice. Cependant, peu de ces méthodes permettent l’analyse de ces contaminants dans des matrices issues de l’élevage agricole intensif. Par ailleurs, les méthodes analytiques disponibles sont souvent sujettes à des faux positifs compte tenu de la complexité des matrices étudiées et du matériel utilisé et ne prennent souvent pas en compte les métabolites et produits de dégradation. Enfin, les niveaux d’analyse atteints avec ces méthodes ne sont parfois plus à jour étant donné l’évolution de la chimie analytique et de la spectrométrie de masse. Dans cette optique, de nouvelles méthodes d’analyses ont été développées pour rechercher et quantifier les antibiotiques dans des matrices dérivées de l’élevage intensif des porcs en essayant de proposer des approches alternatives sensibles, sélectives et robustes pour quantifier ces molécules. Une première méthode d’analyse basée sur une technique d’introduction d’échantillon alternative à l’aide d’une interface fonctionnant à l’aide d’une désorption thermique par diode laser munie d’une source à ionisation à pression atmosphérique, couplée à la spectrométrie de masse en tandem a été développée. L’objectif est de proposer une analyse plus rapide tout en atteignant des niveaux de concentration adaptés à la matrice étudiée. Cette technique d’analyse couplée à un traitement d’échantillon efficace a permis l’analyse de plusieurs antibiotiques vétérinaires de différentes classes dans des échantillons de lisier avec des temps d’analyse courts. Les limites de détection atteintes sont comprises entre 2,5 et 8,3 µg kg-1 et sont comparables avec celles pouvant être obtenues avec la chromatographie liquide dans une matrice similaire. En vue d’analyser simultanément une série de tétracyclines, une deuxième méthode d’analyse utilisant la chromatographie liquide couplée à la spectrométrie de masse à haute résolution (HRMS) a été proposée. L’utilisation de la HRMS a été motivée par le fait que cette technique d’analyse est moins sensible aux faux positifs que le triple quadripôle traditionnel. Des limites de détection comprises entre 1,5 et 3,6 µg kg-1 ont été atteintes dans des échantillons de lisier en utilisant un mode d’analyse par fragmentation. L’utilisation de méthodes de quantifications ciblées est une démarche intéressante lorsque la présence de contaminants est suspectée dans un échantillon. Toutefois, les contaminants non intégrés à cette méthode d’analyse ciblée ne peuvent être détectés même à de fortes concentrations. Dans ce contexte, une méthode d’analyse non ciblée a été développée pour la recherche de pharmaceutiques vétérinaires dans des effluents agricoles en utilisant la spectrométrie de masse à haute résolution et une cartouche SPE polymérique polyvalente. Cette méthode a permis l’identification d’antibiotiques et de pharmaceutiques couramment utilisés dans l’élevage porcin. La plupart des méthodes d’analyse disponibles dans la littérature se concentrent sur l’analyse des composés parents, mais pas sur les sous-produits de dégradation. L’approche utilisée dans la deuxième méthode d’analyse a donc été étendue et appliquée à d’autres classes d’antibiotiques pour mesurer les concentrations de plusieurs résidus d’antibiotiques dans les sols et les eaux de drainage d’un champ agricole expérimental. Les sols du champ renfermaient un mélange d’antibiotiques ainsi que leurs produits de dégradation relatifs à des concentrations mesurées jusqu’à 1020 µg kg-1. Une partie de ces composés ont voyagé par l’intermédiaire des eaux de drainage du champ ou des concentrations pouvant atteindre 3200 ng L-1 ont pu être relevées.
Swine production is a major source of antibiotic release into the environment via manure spreading on agricultural fields. It has been shown that these biologically active compounds may have a toxic impact on ecosystems. Moreover, they are also suspected to cause health problems and contribute to bacterial resistance that could lead to difficult-to-treat infections in humans. Therefore, control of these substances in the environment is necessary. Several analytical methods are proposed in the scientific literature to identify these compounds in various matrices. However, few of these methods allowed the analysis of these contaminants in matrices derived from intensive livestock farming. Furthermore, the analytical methods available are often subject to false positives, given the complexity samples and the equipment used and do not take into account the metabolites and degradation products. Finally, concentration levels reached with these methods are sometimes outdated since the evolution of analytical chemistry and mass spectrometry. In this context, new analytical methods have been developed to investigate and quantify the antibiotics derived from swine husbandry to propose alternative, sensible, selective and robust approaches to quantify these molecules. A first analytical method has been proposed based on an alternative sample introduction technique using the laser diode thermal desorption interface with an atmospheric pressure chemical ionization source coupled to tandem mass spectrometry. The objective was to provide a simpler and faster analysis while reaching levels suitable for the studied matrix. This alternative sample introduction method coupled with an efficient sample processing allowed the analysis of several classes of veterinary antibiotics in swine manure in a short analysis time. Detection limits ranged between 2.5 and 8.3 µg kg-1 and are comparable with those obtained with liquid chromatography in a similar matrix. In order to simultaneously analyze a series of tetracyclines, a second analytical method using liquid chromatography coupled to high-resolution mass spectrometry (HRMS) was proposed. The use of HRMS was motivated by the fact that this mass spectrometer is less sensitive to false positive that the traditional triple quadrupole given the complexity of the studied matrix. Detection limits between 1.5 and 3.6 µg kg-1 have been achieved in swine manure using a fragmentation analysis mode to avoid false positives. Targeted screening methods are interesting approaches when contaminants are suspected to be present in a sample. However, a non-included contaminant in this targeted analysis method could not been detected even at a high concentration. In this context, a non-target compound screening method focused on veterinary pharmaceutical compounds in swine manure was developed using liquid chromatography coupled to high-resolution mass spectrometry. A polymeric SPE cartridge was used to collect polar compounds including pharmaceuticals prior analysis. This method allowed the identification of antibiotics and pharmaceuticals of commonly used in swine farming. Most of the analytical methods available in the literature focus on parent compounds, regardless degradation products. The approach used in the second method of analysis was applied and extended to other classes of antibiotics to measure concentrations of several antibiotic residues in soils and drainage waters of an experimental agricultural field. Field soil contained a mixture of antibiotics and their related degradation products with concentrations measured up to 1020 µg kg-1. Some of these compounds have migrated through the field via drainage waters wherein concentrations up to 3200 ng L-1 were observed.