The application of dairy slurry (DS) to the soil surface in no-till can result in the ammonia (NH3) and nitrous oxide (N2O) emission to atmosphere, with negative repercussions both agronomical and environmentally. The magnitude of these emissions may reduce the expected benefits from the agricultural use of dairy slurry as a nitrogen (N) source to crops. The objective of this work was to evaluate the N2O and NH3 emission according to the method of DS application in soil (surface broadacast vs. shallow injection), with and without the use of the nitrification inhibitor dicyandiamide (DCD) at sowing, associated with the application of urea sidedress. The work was developed in the experimental area of the Department of Soils of the Federal University of Santa Maria (UFSM), in a Hapludalf. The experiment was established in a randomized complete block design with four replications and plots with dimensions of 33 m2 (5,5 m x 6 m). The treatments were: T1- Control; T2- Surface application of mineral fertilization in sowing and urea sidedress (NPK + U); T3- DS broadcast and urea (DSs + U); T4- DSs broadcast with DCD and urea (DSs + DCD + U); T5- DS injected and urea (DSi + U) and T6- DS injected with DCD and urea (DLBi + DCD + U). The N2O evaluations were performed using static chambers and the ammonia was evaluated in the wheat through semi-open static chambers and in the corn through semi-open collectors. Dairy slurry injection in sowing increase N2O emission in 2,198 g ha-1 (56%) in relation to the traditional way of urea use, applying 1/3 of the N at sowing and 2/3 in sidedress. The DCD addition to dairy slurry did not affect the annual N2O emission when the dairy manure was applied on the soil surface in sowing of wheat and corn, compare with exclusive use of urea. The results showed that the lower N2O emission occurred with the use combined of DCD with dairy slurry before its injection into the soil, in sowing of the cultures. NH3 cumulative emissions did not differ between the application of dairy manure in pre-sowing associated with sidedress urea from the traditional mode of exclusive use of urea. The results suggest that N2O and NH3 emissions factors preconized by IPCC are overestimated for dairy manure for Southern Brazil. / A distribuição dos dejetos líquidos de bovinos (DLB) na superfície do solo em plantio direto pode resultar na emissão para a atmosfera de amônia (NH3) e óxido nitroso (N2O), com reflexos negativos tanto do ponto de vista agronômico quanto ambiental. A magnitude destas emissões pode reduzir os benefícios esperados com o uso agrícola dos dejetos como fonte de nitrogênio (N) às culturas. O objetivo do trabalho foi avaliar a emissão de N2O e NH3 em função do modo de aplicação dos DLB no solo, em superfície ou injetado, com e sem o uso do inibidor de nitrificação dicianodiamida (DCD) na semeadura, associado com a aplicação de ureia em cobertura. O trabalho foi desenvolvido na área experimental do Departamento de Solos da Universidade Federal de Santa Maria (UFSM), em um Argissolo Vermelho Distrófico arênico. O delineamento experimental foi blocos ao acaso com 4 repetições. Os tratamentos foram os seguintes: T1- Testemunha, sem aplicação de fertilizantes; T2- Adubação mineral (NPK) aplicada na superfície do solo + ureia em cobertura (NPK + U); T3- DLB na superfície do solo + ureia em cobertura (DLBs + U); T4- DLB com DCD na superfície do solo + ureia em cobertura (DLBs + DCD + U); T5- DLB injetado no solo + ureia em cobertura (DLBi + U) e T6- DLB com DCD injetado no solo + ureia em cobertura (DLBi + DCD + U). Os tratamentos foram aplicados no trigo e reaplicados no milho. A emissão de N2O foi avaliada usando câmaras estáticas, desde a aplicação dos tratamentos no trigo até 22 dias após a colheita do milho, totalizando 364 dias de avaliação. A amônia foi avaliada no trigo através de câmaras semi-abertas estáticas e no milho através de coletores semi-abertos. A injeção dos DLB em pré-semeadura no trigo e no milho, com aplicação de ureia em cobertura, aumentou a emissão anual de N-N2O em 2.198 g ha-1 (56%), em relação ao modo tradicional de uso da ureia nas culturas, aplicando-se 1/3 do N na semeadura e 2/3 em cobertura. A adição de DCD aos DLB não afetou a emissão anual de N2O quando os DLB foram aplicados na superfície do solo em pré-semeadura do trigo e do milho, porém reduziu a emissão anual em 39% quando os DLB foram injetados, não diferindo do tratamento com uso exclusivo de ureia. Os resultados do estudo indicam que a menor emissão de N2O ocorreu com o uso combinado de DCD aos DLB antes da sua injeção no solo, na pré-semeadura das culturas. A volatilização acumulada de NH3 nos tratamentos em que os dejetos de bovinos foram aplicados em pré-semeadura associados à aplicação de ureia em cobertura não diferiu do modo tradicional de uso exclusivo de ureia nas culturas. Os resultados indicam que o fator de emissão de N2O e NH3 preconizado pelo IPCC está superestimado para a aplicação de dejetos de bovinos e ureia no trigo e no milho no Rio Grande do Sul.

Evidências sugerem interação entre o hormônio tireoideano (T3) e os fatores de crescimento fibroblásticos (FGF) no desenvolvimento esquelético. Para estudarmos essa interação, avaliamos o efeito do T3 e do seu antagonista NH3 em células mesenquimais periósticas humanas de pacientes normais e portadores da Síndrome de Apert (SA), que é caracterizada por craniossinostose e causada por mutações no receptor de FGF tipo 2 (FGFR2). Nas células SA, o T3 aumentou o número de células e o NH3 bloqueou esse efeito do T3. O T3 e/ou NH3 aumentaram a atividade da fosfatase alcalina durante a diferenciação osteoblástica das células normais, mas não das mutadas. O T3 aumentou a diferenciação osteoblástica e o NH3 bloqueou esse efeito do T3 em células normais. Nas células mutadas, o NH3 limitou a diferenciação osteoblástica, enquanto o T3 não teve efeito. Concluímos que as células mesenquimais periósticas humanas normais e SA são responsivas ao T3 e NH3, e que o T3 e FGF podem atuar através de vias de sinalização comuns na regulação da diferenciação osteoblástica. / Evidence suggests that there is an interaction between the thyroid hormone (T3) and fibroblast growth factors (FGFs) in the skeletal development. To study this interaction, we evaluated the effect of T3 and its antagonist, NH3, in human periosteal mesenchymal cells from normal and Apert Syndrome (AS) patients, which is characterized by craniosynostosis and is caused by mutations in FGF receptor type 2 (FGFR2). In AS cells, the T3 increased the number of cells and NH3 blocked this effect of T3. T3 and/or NH3 increased the alkaline phosphatase activity in osteoblast differentiation of normal cells, but not in the mutated cells. T3 increased osteoblast differentiation and NH3 blocked this effect of T3 on normal cells. In the mutated cells, NH3 limited osteoblast differentiation while T3 had no effect. We concluded that normal and AS human periosteal mesenchymal cells are responsive to T3 and NH3, and T3 and FGF may act through common signaling pathways in the regulation of osteoblastic differentiation.

La Réduction Catalytique Sélective (SCR) par l'ammoniac, ou l'urée, est un procédé connu de post-traitement permettant de réduire efficacement les oxydes d'azote émis par les motorisations Diesel, en azote et en eau. Les zéolithes échangées au cuivre sont parmi les meilleures formulations pour une application sur véhicules légers, puisque efficaces sur une large zone de température. Le but de cette thèse était d'étudier la stabilité hydrothermale de ce type de catalyseur. L'approche utilisée au cours de ce travail repose sur l'étude des différentes fonctionnalités d'un catalyseur commercial de NH3-SCR présent sous forme de monolithe, à l'état frais et pour différentes conditions de vieillissement, au Banc Gaz Synthétique couplée à une analyse physico-chimique précise de la phase active du catalyseur. Ceci nous a permis de comprendre les phénomènes de désactivation intervenant au cours d'un vieillissement hydrothermal et de mesurer leur impact sur l'activité et la sélectivité de ce type de catalyseur. Après traitement hydrothermal, on assiste à une désalumination plus ou moins importante de la zéolithe, pouvant conduire à l'effondrement de sa structure, ainsi que d'importantes modifications au niveau du cuivre dès les plus faibles températures de vieillissements. Les résultats ont montré l'importance de maintenir une teneur minimal de cuivre en position d'échange, afin de conserver une capacité de stockage en ammoniac suffisante, mais surtout pour garantir une bonne efficacité à basse température en SCR du NO. Le maintien de la structure de la zéolithe semble essentiel pour que le catalyseur conserve une bonne efficacité et sélectivité au cours du temps. / The Selective Catalytic Reduction (SCR) by ammonia, or urea, is a well-known after-treatment process used for converting efficiently the nitrogen oxides, emitted by Diesel engines, into nitrogen and water. Copper-exchanged zeolites are among the most efficient formulations for light-duty applications, since effective over a wide temperature-range. The aim of this thesis is to study the hydrothermal stability of this type of catalyst. The approach used is this work is based on the study of the catalytic properties of a fresh commercial monolith catalyst for NH3-SCR in fresh and after different ageing conditions, at synthetic gas test bench, coupled with a comprehensive physicochemical analysis of the catalyst active phase. This allowed us to understand the deactivation phenomena occurring during a hydrothermal ageing and the impact on the catalyst activity and selectivity. A hydrothermal treatment induces a dealumination of the zeolite, into a more or less significant extent, which can lead to its collapse, as well as important modifications of the copper sites, even at low ageing. The results showed the importance to maintain a minimal copper content into exchanged sites, in order to retain a sufficient ammonia storage capacity, and especially to provide a good efficiency for the SCR of NO at low temperature. The preservation of the zeolite structure seems to be essential in order to maintain the catalyst efficiency and selectivity over time.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Pig Slurry (PS) is used mainly as a fertilizer for crops in southern Brazil where the predominant soil management is in no-tillage. Thus, the application of manure on the soil surface can increase losses of nitrogen (N) for volatilization of ammonia (NH3), leading to reduction in the fertilizing potential of waste and increased environmental pollution. Moreover, as the PS are rich in ammonium N, nitrification can occur quickly and easily and the generated nitrate can also be lost by leaching and denitrification. Then, it is necessary to look for alternatives to mitigate these losses of N fertilizer and maximize the potential of the PS. One of the possibilities to enable greater efficiency and lower pig slurry pollution potential is to perform the application in the soil in split doses, while other strategy is the use of nitrification inhibitors (NI). Thus, the amount of ammonium N applied to the soil surface would be divided into smaller fractions rather than a single application, minimizing the losses by NH3 volatilization and with the delay in the appearance of nitrate (NO3 -) the transfer of this anion to lower soil layers. To evaluate these aspects, experiments were conducted in an Ultisol in no-tillage handled in the agricultural year of 2010/2011, on the campus of Universidade Federal de Santa Maria (UFSM). The treatments were arranged in randomized blocks and evaluated in maize, summer of 2010/2011, and wheat, winter of 2011, consisting the application of PS in a single dose (pre-sowing) and split doses (1/3 in pre-sowing and 2/3 in coverage), with and without the use of nitrification inhibitor dicyandiamide (DCD), present in the product Agrotain® Plus (81 % of DCD) and applied at 7.0 kg ha-1. Besides, a treatment with recommended dose of urea N for both cultures and a control treatment without the use of fertilizer were evaluated. Volatilized NH3 was captured inside the semi-open static chambers containing sponge soaked with a mixture of phosphoric acid and glycerin. Soil samples were collected one day after experiments were set up, and on subsequent days to allow the detection of the changes of inorganic N in soil during the development of both cultures. These samples were analyzed for ammonium N and nitrate N according to Tedesco et al. (1995). The nitrification inhibitor (DCD) maintained N of manure applied to the soil in ammonium form without increasing the emission of NH3 to atmosphere, while the application of PS in parts or not did not differ in the amount of volatilized NH3 and in the percolation of nitrate in the soil. / Os dejetos líquidos de suínos (DLS) são utilizados, principalmente, como fertilizante de culturas comerciais na região Sul do Brasil, onde predomina o manejo do solo em sistema de plantio direto (SPD). Assim, a aplicação desses dejetos na superfície do solo pode potencializar as perdas de nitrogênio (N) por volatilização de amônia (NH3), levando a redução no potencial fertilizante dos dejetos e ao aumento da poluição ambiental. Além disso, como os DLS são ricos em N amoniacal fácil e rapidamente pode ocorrer nitrificação e o nitrato gerado vir a ser perdido também por lixiviação ou desnitrificação. Faz-se necessário então buscar alternativas para mitigar essas perdas de N e maximizar o potencial fertilizante dos DLS. Uma possibilidade de viabilizar maior eficiência fertilizante e menor potencial poluente dos dejetos de suínos é realizar a aplicação de forma parcelada no solo, enquanto outra estratégia é a inibição do processo de nitrificação, por meio do uso de um produto inibidor de nitrificação (IN). Dessa forma, a quantidade de N amoniacal aplicada na superfície do solo seria dividida em frações menores do que com aplicação única dos dejetos, minimizando as perdas por volatilização de NH3 e com o retardamento no aparecimento de nitrato (NO3 -) a transferência desse ânion para camadas inferiores do solo. Para avaliar esses aspectos, os experimentos foram conduzidos em um Argissolo manejado em SPD, no ano agrícola 2010/2011, no campus da Universidade Federal de Santa Maria (UFSM). Os tratamentos foram dispostos em blocos ao acaso e avaliados na cultura do milho, verão 2010/2011, e do trigo, inverno 2011, constando da aplicação de DLS em dose única (pré-semeadura) e parcelada (1/3 em pré-semeadura e 2/3 em cobertura), com e sem o uso do inibidor de nitrificação dicianodiamida (DCD), presente no produto Agrotain® Plus (81 % de DCD) e aplicado em 7,0 kg ha-1. Além destes, foram avaliados um tratamento com a dose recomendada de N ureia para as duas culturas e um tratamento testemunha, sem o uso de fertilizante. A NH3 volatilizada foi captada no interior de câmaras estáticas semiabertas, contendo esponja embebida com a mistura de ácido fosfórico e glicerina. Amostras de solo foram coletadas um dia após a instalação dos experimentos e em dias subsequentes para possibilitar a detecção das transformações de N inorgânico no solo durante o cultivo de ambas as culturas. Essas amostras foram analisadas para N amoniacal e nítrico, conforme Tedesco et al. (1995). O inibidor de nitrificação (DCD) preservou o N dos dejetos aplicados ao solo na forma amoniacal sem aumentar a emissão de NH3 para a atmosfera, enquanto o parcelamento ou não da dose de dejetos não diferiu na quantidade de NH3 volatilizada e na percolação de nitrato no solo.

La présente étude a pour objectif l'obtention d'une équation donnant la vitesse globale de la réaction (activité catalytique) de la réaction NH3-SCR sur des catalyseurs du type V2O5/WO3/TiO2 (a) utilisable pour des conditions expérimentales (pressions partielles des réactifs et des constituants du mélange gazeux et températures) réalistes des conditions des rejets gazeux des centrales à charbon et (b) capable de rendre compte des effets d'empoisonnements chimiques du catalyseur. Cette équation sera implantée dans un logiciel de modélisation de l'évolution des performances des catalyseurs industriels développé par EDF. Pour remplir ces objectifs, les outils et les procédures pour l'approche microcinétique expérimentale ont été appliqués. La caractérisation de la première étape clé qui consiste à adsorbé le réactif NH3 à la surface du catalyseur (type d'adsorption, chaleurs d'adsorption de chaque espèce) a nécessité le développement de la méthode AEIR (initialement adaptée à la caractérisation de CO adsorbé sur des particules métalliques). La réactivité des espèces NH3 adsorbées vis-à-vis des différents réactifs (H2O, NOx, O2) a ensuite été étudiée, conduisant à l'élaboration d'un mécanisme cinétique plausible. A partir de ce mécanisme, un modèle cinétique de la réaction NH3-SCR a été développé et comparé aux données expérimentales obtenues sur catalyseurs modèles et commerciaux. Dans la suite de l'étude, les impacts de plusieurs poisons sur les paramètres contrôlant la cinétique de la réaction ont été déterminés expérimentalement. Dans une dernière partie, un modèle permettant de modéliser les performances catalytique de monolithes a été développé (en intégrant le modèle cinétique mis en place au cours de cette étude) et comparé à des données expérimentales / The aim of the study is to obtain an equation for the overall reaction rate of the NH3-SCR reaction over V2O5/WO3/TiO2 catalysts (a) used for the experimental conditions (partial pressure of components of the gas mixture and temperature) realistic conditions of discharges from coal power plant and (b) able to take into account the chemical poisoning effects of the catalyst. This equation will be implemented in software developed by EDF for modeling the evolution of the performance of industrial catalysts. To fulfill these objectives, tools and procedures for the experimental microkinetic approach were applied. The characterization of the first key step of the reagent adsorbed NH3 on the surface of catalyst (type adsorption, heats of adsorption of each species) has necessitated the development of the AEIR method (initially adapted to the characterization of CO adsorbed on metal particles). The reactivity of the NH3 adsorbed species to the various reagents (H2O, NOx, and O2) was then studied, leading to the development of plausible kinetic mechanism. From this mechanism, a kinetic model of the NH3-SCR reaction has been developed and compared to experimental data obtained on model and commercial catalysts. In the remainder of the study, the impacts of several poisons to parameters that control the kinetics of the reaction were determined experimentally. In the last part, a model of catalytic monoliths performances was developed (by integrating the kinetic model developed in this study) and compared to experimental data

One of the most crucial issues nowadays is the protection of the environment and the replacement of fossil fuels, which are abundantly used around the world, with more efficient and renewable sources. The highest portion of global energy demands today is used in heating and cooling purposes. One way of alleviating the fossil-based thermal energy uses is to harvest excess thermal energy using thermochemical storage materials (TCMs) for use at heating/cooling demands at different times and locations. Along this, in this master’s thesis, a bench-scale thermochemical heat storage (TCS) system is numerically designed, as a part of a collaborative project: Neutrons for Heat Storage (NHS), funded by Nordforsk. The TCS system that is designed herein employs the reversible chemical reaction of ammonia with a metal halide (MeX) for a heat storage capacity of 0.5 kWh, respectively releasing and storing heat during absorption and desorption of ammonia into and from the MeX. This system is designed for low temperature heat applications, around 40-80 °C. SrCl2 is chosen as the metal halide to be used, based on the research outcomes in determining the most suitable materials conducted by NHS project partners. In the ammonia-SrCl2 system, only the absorption and desorption between SrCl2∙NH3 and SrCl2∙8NH3 are considered. The main reason is because absorption/desorption between the last ammine and SrCl2 undergoes at a significantly higher/lower reaction pressure (for a given temperature), with a significant volume change compared to the rest of the ammines, and therefore is practically less cost effective. This thesis also includes a detailed discussion of four different thermochemical storage designs from literature, found as the most relevant to the present TCS system study, which use the reaction between ammonia and metal halides. The first system that was examined is a TCS system built by the NHS project partners at Technical University of Denmark (DTU), owing to its similarities with the desired project, regarding the design and parameters the system uses. This system works in batch mode, only allowing either absorption (i.e. heat release) or desorption (i.e. heat storage) at a given cycle. Thus, upgrading the design of this TCS system at DTU is considered as a most-likely solution to the research objectives of this current thesis project. Moreover, the TCS system at DTU uses storage conditions and desorption temperature similar to the current project’s desired low temperature range of 40-80 °C. The second system discussed herein from literature uses two reactors for cold and heat generation, which means that both charging and discharging processes occur simultaneously. This simultaneous operability is the main reason that this particular system was examined in this thesis. The next discussed system from literature also uses two reactors, for absorption and desorption processes, which work reversibly when each process is completed, like in the desired concept of this project. These two systems (i.e., the secondly and the thirdly discussed systems) use the reversible solid-gas reaction for absorption and desorption between SrCl2∙NH3 and SrCl2∙8NH3, however, the conditions of pressure and temperature between them differ. The second system from literature operates at desorption and absorption at respective conditions of 96 °C, 15 bar and 87 °C, 11 bar while the third system discussed operates at 103 °C, 16 bar and 59 °C, 3 bar during desorption and absorption respectively. The last system from literature that is discussed herein provides the same desorption temperature of 80 °C. Inaddition this particular study suggests that the reaction of solid with gaseous NH3 is better (than the solid with liquid NH3 reaction) based on results derived from several different low-pressure experiments of the reactions. The main differences between all these discussed systems from literature, as opposed to the desired TCS system design in this thesis project, concern the systems’ operating mode and the pressure and temperature-conditions. The first difference is that only one of the examined systems pumps the solid VIII powder salt around the system in contrast to the others that keep the salt static inside the reactors and pumped only the ammonia around the system, as chosen in the current system. The second difference concerns the operating conditions during absorption and desorption reactions, where these different systems operate at a widely different pressure and temperature conditions as compared to the current system expectations. Thus, there are four main lessons that were learnt via this literature analysis, to improve the TCS system at DTU to the desired new system in this work. The first lesson is related to the reactants’ transportation mechanism that should be used in this system. Regarding this, it was decided to maintain the solid salt (metal halide) stationary inside each reactor (but not pumping it instead of ammonia), similar to the majority of designs discussed from literature. According to the second and third lessons, the solid-gas reaction is the most suitable solution and only the reactions of absorption and desorption between SrCl2∙NH3 and SrCl2∙8NH3 are considered, following the experience from literature (for the reasons explained earlier). The last lesson regards the system’s suitable operating conditions and more specifically the TCS system’s temperatures that should match the district heating temperatures. Thus, the temperature point that was chosen as a priority was 80 °C, from the range 40- 80 °C set in the partner project NHS. To maintain this condition, therefore, the most suitable condition of pressure of both reactions (according to the equilibrium pressure vs temperature curve) was chosen to be at around 8 bar. This same pressure was chosen for both reactions, since the pressure difference between these reactors and the storage of ammonia (i.e. from 8 to 10 bar) should be as small as possible due to the high costs that can arise in the case of a higher pressure difference (i.e. requiring more compressors and heat exchangers). Inspired by these literature cases, firstly a conceptually suitable TCS system was proposed in this project and after that the final desired system was designed and was implemented and evaluated numerically. The numerical design and optimization of the chosen TCS system was performed herein by using the software Aspen Plus (version 9), which contains both fluids and solids in a simulation environment, using consistent physical properties. This TCS system is designed to store and release heat at around 80 °C and 8 bar through absorption and desorption by using two identical reactors respectively. Each reactor includes the amount of around 1 kg (more specifically 0.985 kg) strontium chloride salt reacting with 1.7 kg of ammonia. A verification system is also modelled in Aspen, using available experimental data from literature. Here, the modelled novel system design was adapted to this chosen other system layout from literature which uses the same reaction pair, yet at different operating conditions. This adapted system design in Aspen was then used to verify the chosen configuration and the reliability of the constructed system for the NHS project. Good agreements between the modelled results in Aspen against the available experimental data of this verification model are obtained. A sensitivity analysis is also conducted herein on the proposed novel TCS system to identify the optimum operating conditions and the behaviour of the chosen most important parameters of the system. The designed system provides an energy storage capacity of 0.5 kWh for the specific amounts (in volumetric flow rates) of ammonia and monoammine of strontium chloride, that comes from the analysis, of 1.08696 e-05 kmol/s and 1.5528 e-06 kmol/s respectively. For these specific values of the HTF, the analysis showed that the volumetric flow rates of the heat and cold external sources must be 1.56 l/min (which is decreasing with the increase of the inlet HTF temperature) and 0.42 l/min (which is increasing with the increase of the inlet HTF temperature) respectively. In conclusion, this study presents an ammonia-SrCl2 TCS benchscale system design that allows continuous heat storage and release, in an easy-to-scale up design, also suggesting optimum operating conditions. / En av de mest avgörande frågorna i dag är skyddet av miljön och utfasningen av fossila bränslen som används allmänt över hela världen för mer effektiva och förnybara resurser. Den största delen av den globala energibehovet idag avser uppvärmnings- och kylapplikationer. Ett sätt att minska fossilbaserad termiskenergianvändning är att lagra överskottsvärmeenergi genom termokemiska lagringsmaterial (TCM) och använda den för värme- och kylbehov vid olika tidpunkter och platser. I samband med detta är ett termokemiskt värmelagringssystem numeriskt utformat i detta mastersexamensprojekt, som en del av ett samarbetsprojekt Neutrons for Heat Storage (NHS) finansierat av Nordforsk. Det termokemiska lagringssystemet (TCS) som är konstruerat utnyttjar den reversibla kemiska reaktionen av ammoniak med en metallhalogenid (MeX) för en värmelagringskapacitet på 0.5 kWh, och frigör och lagrar värme respektive under absorption och desorption av ammoniak till och från MeX. Systemet är designat för lågtemperaturuppvärmningstillämpningar runt 40-80 °C. SrCl2 väljs som det mest lämpliga metallhalogeniden för systemet, baserat på studier som utförts av NHS-projektpartnerna. I ammoniak SrCl2-systemet beaktas endast absorption och desorption mellan SrCl2NH3 och SrCl28NH3. De huvudsakliga orsakerna till detta är att absorptionen/desorptionen mellan den sista aminen och SrCl2 kräver ett betydligt högre/lägre reaktionstryck (för en given temperatur), och resulterar i en betydande volymförändring jämfört med resten av aminerna, och är därför praktiskt taget mindre kostnadseffektivt. Detta mastersexamensprojekt inkluderar en detaljerad genomgång av fyra olika TCS-system från litteratur som använder reaktionen mellan ammoniak och metallhalogenider. Dessa väljs här eftersom dessa anses vara de mest relevanta (från litteratur) jämfört med det valda systemet i denna studie. Det första undersökta systemet är ett system byggt av NHS-projektpartnerna vid Danmarks Tekniska Universitet (DTU). Detta har valts på grund av likheterna med det önskade systemet i det aktuella mastersexamensprojektet, vad gäller systemdesign och parametrar. Detta system fungerar i batch-läge, vilket endast tillåter antingen absorption (dvs värmeavgivning) eller desorption (dvs värmelagring) under en specifik cykel. Således kan en uppgraderad design av detta TCS-system vid DTU möjligen vara en lämplig lösning på forskningsmålen för detta mastersexamensprojekt. Dessutom använder detta TCS-system från DTU ganska liknande driftsförhållanden (temperaturer och tryck) i nivå med det aktuella projektets önskade lågtemperaturintervall på 40-80 °C. Det andra systemet från den litteratur som diskuterats använder två reaktorer för kyla och värmeproduktion, vilket innebär att både laddningsoch urladdningsprocesser sker samtidigt. Denna samtidiga operation är främst anledningen till att systemet undersöktes, eftersom detta är en önskad funktion att uppnå i det aktuella projektet. Nästa system från den litteratur som diskuteras häri använder också två reaktorer för absorptions- och desorptionsprocesser, som fungerar reversibelt när varje process är klar, precis som önskat i detta projekt. Dessa två system (dvs det andra och det tredje diskuterade systemen) använder den reversibla fastgasreaktionen för absorption och desorption mellan SrCl2NH3 och SrCl28NH3, dock vid olika tryck- och temperaturförhållanden. Det andra systemet arbetar nämligen under kombinationer av absorption och desorption av 96 °C, 15 bar och 87 °C, 11 bar, medan det tredje systemet arbetar vid 103 °C, 16 bar respektive 59 °C, 3 bar. Det sista systemet som diskuterats från litteraturen arbetar vid samma temperatur som det önskade systemet gör (dvs. 80 ° C) och genom olika lågtrycksexperiment visar att den fasta salt-gasreaktionen är ett bättre val än reaktionen av det fasta saltet med flytande gasreaktion. De viktigaste skillnaderna mellan alla dessa diskuterade system från litteratur i motsats till det önskade TCS-system i detta mastersexamensprojekt, avser systemdriftläge samt deras tryck och X temperaturförhållanden. Den första skillnaden är att endast ett av alla undersökta system pumpar saltet i fast pulverform, till skillnad från de andra som håller saltet stillastående i reaktorerna och endast pumpar ammoniak. Den andra skillnaden gäller driftsförhållandena under absorptions- och desorptionsreaktioner där dessa system arbetar vid mycket olika tryck- och temperaturförhållanden jämfört med det nuvarande systemet. Således, från översynen av alla system, finns det fyra huvudsakliga lärdomar för att förbättra TCS-systemet vid DTU till det önskade nya systemet. Den första är relaterad till reaktanttransportmekanismen som bör användas i detta system. I detta avseende har det beslutats att hålla det fasta saltet (metallhalogenid) stillastående i varje reaktor (men inte pumpa det istället för ammoniak), till skillnad från de flesta system i litteraturen. Enligt dem andra och tredje lektionerna är den fasta gasreaktionen den mest lämpliga lösningen och endast reaktionerna på absorption och desorption mellan SrCl2∙NH3 och SrCl2∙8NH3 bör övervägas enligt erfarenheten från litteraturen (av de skäl som förklarats tidigare). Den sista lärdomen avser systemets lämpliga driftsförhållanden och mer specifikt TCS-systemets temperaturer för att matcha fjärrvärmetemperaturerna. Den temperaturpunkten valts som prioritet, från området 40-80 °C inställt av moderprojektet NHS, sattes till 80 °C. För att bibehålla detta tillstånd var det lämpligaste tryckvillkoret för båda reaktionerna (enligt jämviktstrycket kontra temperaturkurva) valdes att ligga på cirka 8 bar. Samma tryck valdes för båda reaktionerna, eftersom tryckskillnaden mellan dessa reaktorer och lagring av ammoniak (dvs. från 8 till 10 bar) borde vara så liten som möjligt på grund av de höga kostnaderna som kan uppstå vid högre tryckskillnad (dvs. fler kompressorer krävs och värmeväxlare). Inspirerad av denna litteratur föreslogs för det första ett konceptuellt lämpligt TCS-system i detta mastersexamensprojekt, varefter det slutliga systemet implementerades och utvärderades numeriskt för de önskade förhållandena. Den numeriska utformningen och optimeringen av det valda TCS-systemet utfördes här med hjälp av programvaran Aspen Plus (version 9), som innehåller både vätskor och fasta ämnen i en simuleringsmiljö, med konstant fysiska egenskaper. Detta TCS-system är utformat för att lagra och släppa värme vid cirka 80 °C och 8 bar genom absorption och desorption med användning av två identiska reaktorer respektive. Varje reaktor innefattar cirka 1 kg (närmare bestämt 0.985 kg) strontiumkloridsalt reagerande med 1.7 kg ammoniak. Ett verifieringssystem modelleras också i Aspen med hjälp av tillgängliga experimentella data från litteraturen. I detta anpassades den modellerade nya systemdesignen till denna valda andra verifieringssystemlayout från litteratur, som använder samma reaktionspar, men under olika driftsförhållanden. Denna anpassade systemdesign i Aspen användes sedan för att verifiera den valda konfigurationen och tillförlitligheten för det designade systemet för NHS-projektet. Här erhålls ett bra avtal för denna verifieringssystemdesign mellan Aspenmodellresultaten och experimentdata. Här utförs också en känslighetsanalys för det utformade TCSsystemet i det aktuella projektet för att identifiera de optimala driftsförhållandena och beteendet för de valda viktigaste parametrarna i systemet. Det konstruerade systemet ger en energilagringskapacitet på 0.5 kWh för de specifika mängderna (i volymflöde) av ammoniak och monoamin av strontiumklorid, som kommer från analysen, av 1.08696 e-05 kmol/s och 1.5528 e-06 kmol/s respektive. För dessa specifika värden på värmeöverföringsvätskan visade analysen att de volymetriska flödeshastigheterna för värme och kalla yttre källor måste vara 1.56 l/min (vilket minskar när temperaturen på värmeöverföringsvätskan ökar) och 0.42 l/min (som ökar när temperaturen på värmeöverföringsvätskan ökar). Sammanfattningsvis presenterar denna studie ett ammoniak-SrCl2 TCS-bänkskålsystem som möjliggör kontinuerlig värmelagring och frigöring, har en design som är lätt att anpassa och föreslår också optimala driftsförhållanden.

La pollution atmosphérique malodorante provient essentiellement de quatre gaz SO2, H2S, NO2 et NH3. Afin de réduire au mieux ces effets néfastes sur la santé et l'environnement, il faut contrôler en continu les émanations de gaz le plus près possible de la source. Ce qui nécessite un appareil capable de détecter ces gaz polluants, simple d'utilisation, de taille et poids réduits. C'est dans cette optique que nous avons réalisé un nez électronique portable, servant à détecter les quatre gaz cibles déjà cités. La partie sensible de ce prototype est constituée d'une matrice de six capteurs à oxydes métalliques semi-conducteurs, dont nous utilisons la sensibilité croisée. Le nez électronique fonctionne sur le même principe que le nez humain, il doit apprendre à reconnaître une odeur. Cette phase d'apprentissage se déroule au laboratoire où nous envoyons sur les capteurs des mélanges gazeux connus et contrôlés. La réponse des capteurs varie en fonction de la nature du gaz (réducteur ou oxydant) et de leur sensibilité à celui-ci. Puis l'utilisation de méthodes d'analyse de données a prouvé que notre nez électronique peut discriminer un mélange gazeux complexe et le quantifier. Ensuite nous avons placé le nez électronique en situation réelle, en étudiant l'odeur dégagée par des fientes de canards dans une ferme expérimentale. Les résultats obtenus ont montré que cet appareil pouvait détecter de manière fiable les variations d'odeur en fonction des paramètres influents. Ainsi, nous avons réalisé la validation de notre prototype en laboratoire puis sur site. Mais les capteurs utilisés présentent un inconvénient, ils doivent conserver sans interruption leur température de fonctionnement (~ 350°C). Afin de prévenir cette forte consommation d'énergie, nous avons développé des capteurs polymères qui fonctionnent à température ambiante. La caractérisation en laboratoire a montré qu'ils sont sensibles aux gaz cibles étudiés. Leurs réponses à H2S laisse apparaître une bonne stabilité à court et moyen terme, qui permettra de les intégrer dans la matrice après complet développement / The malodorous atmospheric pollution results essentially from four gases SO2, H2S, No2 and NH3. To reduce at best these fatal effects on the health and the environment, it is necessary to control continuously the gas emanations closer to the source, That requires adevice enable to detect these polluant gases, easy to use, with reduced size and weight. In this way, we have realized a portable electronic nose, to detect of the four target gases already mentioned. The sensitive part of this prototype is composed of a matrix of six semi conducting metal oxide sensors, offering a good cross sensivity. The electronic nose mimics the human nose, he has to learn to recognize an odour. This learning phase is realised in the laboratoy by introducing in the sensor cell gas mixtures with controlled composition, The sensor response varies with the nature of the gas (reducing or oxidizing) and their own gas sensitivity. The use of analysis and data methods proves that our electronic nose can well discriminate a complex gas mixture and quantify it. Then, we have placed the electronic nose in a real situation, by studying the odour coming from a duck experimental farm. The obtained results showed that this prototype could well detect the variations of the odour level in accordance with the influent parameters. So, we have realized the laboratory and the real site validation of our electronic nose. But the metal oxide sensors present an inconvenient : they have to keep continuously their working temperature (~ 350°C). To prevent this strong energy consumption, we have developed polymer sensors which work at room temperature. The characterization in laboratory showed that they are sensitive to studied target gases. Their responses to H2S have a good stability in short and middle term, allowing to integrate them into the matrix after complete development

L'ammoniac atmosphérique (NH3) est principalement émis par l'agriculture. C'est le principal composé alcalin de l'atmosphère et il joue un rôle essentiel dans la chimie de l'atmosphère. Les dépôts humides et secs d'NHx (NH3 + NH4+) ont des effets négatifs directs (toxicité à fortes doses) ou indirects acidification, eutrophisation, baisse de la résistance aux stress) sur les écosystèmes naturels ou cultivés.<br />La plante peut être un puits ou une source d'NH3 pour l'atmosphère. Le sens et l'intensité des échanges dépendant du gradient de concentration entre la cavité sous stomatique et l'air. La concentration en ammoniac dans la cavité sous stomatique appelée aussi point de compensation stomatique pour l'ammoniac est déterminée par la température de la feuille, la concentration en ammoniaque ([NH4+]ap) et le pH du liquide apoplastique. Ces deux derniers paramètres dépendent du métabolisme azoté de la feuille et des diverses entrées et sorties de composés à travers le xylème et le phloème. Jusqu'à présent, seuls des modèles empiriques ont été conçus pour modéliser le point de compensation stomatique pour l'ammoniac.<br />Pour analyser le determinisme du point de compensation pour l'ammoniac, nous avons conçu une expérimentation pour mesurer sa variabilité pour de jeunes plantes de colza en fonction de la nutrition azotée et des conditions jour et nuit. Deux méthodes de mesures ont été utilisées : l'extraction d'apoplaste et la chambre à flux. Les deux méthodes montrent une corrélation positive entre la concentration en ammonium dans la solution nutritive et le point de compensation. Par contre la concentration en nitrate a peu d'influence sur le point de compensation de même qu'une alimentation mixte ammonium et nitrate réduit le point de compensation par rapport a une alimentation a même concentration en ammonium. Le point de compensation mesuré de jour n'est pas significativement différent du point de compensation mesuré de nuit même si il a tendance à être plus fort.<br />Le modèle construit est un modèle a compartiment ; il est couplé à un modèle de continuum sol plante atmosphère donnant des flux d'eau et en particulier la conductance stomatique. Il intègre un modèle de photosynthèse et les principales sources et puits d'ammoniac dans une cellule. Le modèle montre une forte dépendance du point de compensation stomatique du flux d'eau, de la température et de la concentration en ammonium dans le xylème.

La prise de conscience de l'importance de la gestion des déchets et de la préservation des ressources a conduit de plus en plus d'acteurs du monde agricole à s'intéresser au compostage comme mode de traitement d'effluents d'élevage ou de boues de stations d'épuration. Les filières d'utilisation de ces substrats, épandage, compostage ou autre, doivent donc être comparées. On sait en effet que l'agriculture est responsable d'une part importante des émissions d'ammoniac (NH3) et de protoxyde d'azote (N2O) et ainsi, indirectement ou directement, de l'augmentation de la concentration de N2O dans l'atmosphère. Trois séries d'expérimentations ont été menées respectivement sur des mélanges d'écorces de peuplier et de fientes de poules pondeuses, sur du fumier de poulet sans ou avec additifs et sur un mélange de paille et de boues de station d'épuration rurale, en parallèle avec un nouveau mélange d'écorces et de fientes. La première a permis de mesurer les émissions de gaz azotés d'un andain (25 m3) en cours de compostage. Elles étaient de 50% environ de l'azote initial sous forme N- NH3 et de moins de 1% sous forme N-N2O. La production de N2O était associée à des activités de nitrification/dénitrification et avait principalement lieu en phase de maturation. La seconde a révélé, pour du compostage de courte durée (1,5 mois) et en taille expérimentale (2 m3), les conditions dans lesquelles les émissions de NH3 et de N2O étaient les plus fortes ou les plus faibles et lesquelles favorisaient l'activité de dénitrification des micro-organismes. L'augmentation du rapport carbone/azote et l'addition de composés ou microorganismes adéquats font passer les pertes en NNH3 de 55 à 7% de l'azote initial. Leur effet sur la libération de N2O (0,2-0,9%) dépend de nombreux facteurs. La troisième a montré que les andains de compostage (10 et 25 m3) devaient être considérés comme des écosystèmes à part entière composés de différents compartiments (grossièrement entrée, fond, sortie et croûte) où les populations microbiennes s'organisent différemment, l'entrée étant productrice de N2O, le fond et la sortie, producteurs, en équilibre ou consommateurs suivant les moments. La taille de l'andain en expérimentation est donc une donnée capitale pour considérer les résultats comme représentatifs de la réalité.

Recently, memory-cells employing discrete traps as the charge storage media have been attracting a lot of attention as a promising candidate to replace conventional DRAM or Flash memories. Conventional floating gate (FG) non-volatile memories (NVMs) present critical issues on device scalability beyond the sub-50nm node. In achieving non-volatility in conventional FG memories, thicker control and tunnel oxide (~8nm) are required to guarantee longer retention time. Relatively, nano-dots memories causes more resistant leakage charges by localized storage sites, thus improving the device retention characteristics. Hence, nano-dots memories allow more aggressive scaling of the tunnel oxide and exhibit superior characteristics compared to Flash memories in term of operation voltage, write / erase speed, retention time and endurance. The advantages of metal nano-dots compared with other material counterparts include higher density of states , stronger coupling with the channel, better size scalability, and the design freedom of engineering the work function to optimize device characteristics. However, tungsten nano-dots are the most interested in all of metal dots is that tungsten metal has more extra attractive advantages, such as ultra high melting point make high process temperature caused superior thermal stability of device and wide application in VLSI technology nowadays caused real possibility of tungsten nano-dots NVMs fabricated in industry in practice. This dissertation is divided into four sections: (1) discussion of basic properties for tungsten nano-dots memory devices; (2) Tunneling Oxide Engineering,; (3) Improvement by novel processes; and (4) The influence with supercritical CO2 (SCCO2) and vapor treatment. Initially, formative mechanism of tungsten nano-dots and electrical characteristics of devices was investigated in the first section. Tungsten nano-dots were formed by oxidizing tungsten silicide / amorphous silicon double stack film at high temperature condition. From electrical measurement, the better characteristics have been achieved for oxidation condition at 1050¢XC / 120 sec. Secondly, the rapid thermal anneal (RTA) oxidation is used to grow tunnel oxide by two different forming gas (O2/N2O). Comparison of electrical characteristics, program characteristics of the device using tunnel oxide with N2O process is inferior than the common device. However, endurance is a important electrical characteristics in the semiconductor device especially apply on the non-volatile memory. Thirdly, novel processes were employed into fabrication of tungsten nano-dots memory devices, include the N2O oxidation and NH3 plasma treatment. The purpose of novel processes is production additional trapping states in nonvolatile memories, which is considerably as combination nano-dots with SONOS structure. In the final section, the application of supercritical CO2 with vapor on tungsten nano-dots memoery devices have been studying. It is found that the device treated by SCCO2 which electrical characteristics is improved obviously. Furthermore, this technology also can fabricate the nano-dots memory which is like the device used high temperature oxidation process. It suggests that the SCCO2 with vapor treatment could oxidize silicide film under a low temperature environment. This novel oxidation process has some advantages and could be noticed in the semiconductor industry.