Дисертації з теми "Fines production"

This thesis work focuses on multiphase flow in the oil and gas industry. As differences in temperatures and pressures come to play from the reservoir to the surface, in tubing and in pipelines, gas tend to dissolve and evolve out from oil, with water and solid particles making their way into the production flow stream, giving rise to a multiphase gas-liquid-solid production and transportation. A review of sand and fines production worldwide was carried out and concluded that sand production is a common occurrence in the petroleum industry, present in all the major oil producing regions of the world. Multiphase flow patterns were equally discussed in this work stating the different flow regimes available in the vertical and horizontal pipe system. HYSYS was used to obtain fluid properties for volatile oil used in the determination of major parameters such as fluid velocities, hold-ups and pressure drop. Results did show that particle velocity to a large extent depended on the fluid velocity, which would always be higher with increasing amounts of gaseous phase present as experienced in annular and slug flow. The velocity profile chart showed the sand peak velocities in annular and slug flow as 13.2 m/s and 9.8 m/s. It was also observed that pressure drop along a pipe will under normal conditions tend give a positive slope when plotted against superficial fluid velocities.

The use of washable baghouses for fines collection in milk powder plants has been investigated. The main aim of this study was to increase the fundamental understanding of both operation and design of washable baghouses for application in milk powder plants. This work has focussed on the industrial scale. Industrial plant operating data has been collected, plant designs compared and analyses conducted on powder produced at the industrial scale. The amount of powder that becomes fines, the small size fraction of powder entrained in spray dryer outlet air streams, has been shown to be significantly greater than the traditionally vague estimate of 10 % to 20 %. The ratio of fines flows to total powder flows ranged from 49 ± 8 % to 86 ± 2 % depending on the powder type and plant operating conditions. A simple yet reliable method was developed to quantify fines flows based on measured powder size distributions of samples taken from around the plant. These estimates were supported by readings from an online optical scintillation instrument, which was shown to be capable of measuring fines flows at concentrations approximately four times the supposed maximum stated by the instrument’s manufacturer. Observations in another part of this work supported previous Fonterra observations showing that the amount of bulk fat in skim milk powder (SMP) has a large influence on the baghouse differential pressure. Fines flows measured by the optical scintillation instrument and analysis of other plant operating data showed that a change in bulk fat in SMP does not appear to cause any change in fines concentration. Observations of the surface of SMP by scanning electron microscopy, and electron spectroscopy for chemical analysis, both showed that fat is over-represented on the surface of the particles, and that only small increases in the bulk fat content are required to cause large increases in the surface fat coverage. It is hypothesised that increased fat on the surface of particles increases the clumping of SMP before deposition on the bags. Consequently, the powder forms more porous cakes and is less likely to penetrate into the interior of the filter bags, which also makes it easier to pulse clean powder from the filter bags. Therefore, the baghouse differential pressure is reduced. The design of pulse-jet baghouses from the literature was found to rely heavily on the authors past experience and approach, giving rise to large variation in recommended values of the key design parameters. A procedure for determining the optimal combination of these parameters was developed. This procedure showed that the main Fonterra washable baghouses are far from optimal because of their high air-to-cloth ratios, long bags and high elutriation and annular velocities. This procedure also showed that the Fonterra vibrating fluid bed washable baghouses are much closer to the optimum, which is the probable reason these washable baghouses have had almost no operational issues. Observations of the movement of the bags from below showed significant movement for bags near the inlet of the baghouse, indicating that this was the probable cause of the high bag damage in this zone. It is suggested that increasing the outer gap (distance between the baghouse wall and the bag on the edge of the bag bundle) be investigated further in an attempt to slow the annular velocity around the edge of the bag bundle and reduce bag movement. It is also recommended that stainless steel inspection hatches installed in the wall of a baghouse for this research, be included in all current and future washable baghouses because use of these hatches reduced the overall clean-in-place turn around time by 20 %. Computational fluid dynamics simulations of the air flow patterns within the Clandeboye Dryer 2 chamber were carried out using a commercial code CFX10.0. These simulations are possibly the first to include the influence of a spray dryer’s internal fluid bed airflow on the flow patterns within a spray dryer. As expected, the simulations showed the main air jet oscillated and precessed about the central axis with no apparent distinct frequency. In turn, the recirculation zones between the main jet and the chamber walls fluctuated in size. Different fluid bed flows within the industrial range had only a local influence on the air only flow field by reducing the length of the main jet. A different outlet boundary condition (including a flow resistance representing the baghouse) also appeared to have little influence on the overall flow field. Good agreement was found between the movements of the main jet via simulations and from telltale tufts installed in the plant dryer. This supported other indications that the simulations were an accurate representation of the actual flows. It was concluded that this project achieved its main aim of improving the fundamental understanding of washable baghouse operation and design, especially for application in milk powder plants. Also this project, as well as a change in production schedules, has helped to reduce downtime associated with the washable baghouses in the Fonterra Clandeboye Dryer 2 plant by an estimated 50 hours per annum.

La sigillée est la céramique de table d'époque romaine par excellence. Son processus de fabrication et les mécanismes de sa commercialisation sont relativement bien connus en Méditerranée occidentale, mais il n'en est pas de même pour la Méditerranée orientale. Chypre offre un cadre particulièrement favorable pour aborder cette problématique puisqu'elle a connu dans l'Antiquité, une forte tradition de potiers. Ceux-ci ont notamment produit du début du Ier s. Av. Notre ère jusqu'à la fin du IIe s. De notre ère une production de "Cypriot sigillita", puis une autre à l'époque proto-byzantine ("Cypriot red slip ware"). En outre, la situation géographique de l'île, située à un carrefour de grands axes commerciaux, explique la présence de nombreuses importations occidentales (sigillée italique) et orientales ("Eastern sigillita" A, B et dans une moindre mesure C). Grâce au matériel inédit provenant du site de Kition, il a été possible de mettre en évidence le rôle de relais que Chypre avait joué dans la redistribution de ces céramiques, et de s'interroger sur les facteurs historiques responsables de leur déclin.

Almost all research on biorefinery concepts are based on chemical pulping processes and ways of utilising lignin, hemicelluloses and extractives as well as a part of the remaining cellulose for production of nano materials in order to create more valuable products than today. Within the Forest as a Resource (FORE) research program at FSCN we are utilising the whole chain of unit processes from forestry to final products as paper and board, where the pulping process research focus on high yield process as TMP and CTMP. As these process solutions are preserving or only slightly changing the properties of the original wood polymers and extractives, the idea is to find high value adding products designed by nature. From an economic perspective, the production of nanocellulose from a chemical pulp is quite expensive as the pulp has to be either enzymatically (e.g. mono-component endoglucanase) pre-treated or chemically oxidised using the TEMPO (2,2,6,6 - tetramethyl-piperidine-1-oxil) - mediated oxidation method in order to make it possible to disrupt the fibres by means of homogenisation. In high yield pulping processes such as in TMP and CTMP, the idea with this study was to investigate the possibility to use fractions of low quality materials from fines fractions for the production of nano-ligno-cellulose (NLC). The integration of a NLC unit process in a high yield pulping production line has a potential to become a future way to improve the quality level of traditional products such as paper and board grades. The intention of this research work was that, by using this concept, a knowledge base can be created so that it becomes possible to develop a low-cost production method for its implementation. In order to study the potential of this concept, treatment of thermo-mechanical pulp (TMP) fines fractions were studied by means of homogenisation It seems possible to homogenise fine particles of thermo-mechanical pulp (1% w/v) to NLC. A correspond fines fraction from bleached kraft pulp (BKP) was tested as a reference at 0.5% w/v concentration. The objective presented in this work was to develop a methodology for producing mechanical pulp based NLC from fines fractions and to utilise this material as strength additives in paper and board grades. Laboratory sheets of CTMP and BKP, with addition of their respective NLC, were made in a Rapid Köthen sheet former. It was found that handsheets of pulp fibres blended with NLC improved the z-strength and other important mechanical properties for similar sheet densities. The characterisation of the particle size distribution of NLC is both important and challenging and the crill methodology developed at Innventia (former STFI) already during the 1980s was tested to see if it would be both fast and reliable enough. The crill measurement technique is based on the optical responses of a micro/nano particle suspension at two wavelengths of light; UV and IR. The crill value of TMP and CTMP based nano-ligno-cellulose were measured as a function of the homogenisation time. Results showed that the crill value of both TMP-NLC and CTMP-NLC correlated with the homogenisation time.

L'hypothèse de l'assurance prévoit que les forêts composées de mélanges d'espèces d'arbres pourraient mieux résister aux conditions environnementales stressantes que les forêts composées d'une seule espèce d'arbre. La majorité des travaux antérieurs ont testé cette hypothèse en se focalisant sur la productivité et les variables de réponse associées sans prendre en compte les processus souterrains. L’objectif principal de ma thèse était d’étudier l’effet de la diversité des espèces d’arbres sur les processus souterrains impliqués dans la décomposition des racines à travers des gradients climatiques. J'ai émis l'hypothèse que le mélange d'espèces ayant des systèmes racinaires contrastés entraînerait une faible compétition souterraine, et se traduirait par la production de plus biomasse de racines fines. En outre, j'ai émis l'hypothèse que les racines ayant des caractéristiques chimiques et morphologiques contrastées dans les peuplements mixtes se décomposent plus rapidement. Dans des conditions de stress hydrique, j'ai émis l'hypothèse d'une décomposition plus lente mais d’une atténuation des mélanges d'arbres sur la décomposition en raison de l'amélioration des conditions micro-environnementales. Pour tester ces hypothèses, j'ai examiné la variation des caractéristiques fonctionnelles des racines et leurs conséquences sur les flux de C, N et P à l'échelle de l'écosystème à travers l’étude de : 1) la ségrégation verticale des racines et la biomasse des racines fines, 2) la dynamique des racines fines et les flux de nutriments associés et 3) la décomposition des racines fines et des feuilles mortes. Dans ce cadre, trois deux expériences de terrain ont été réalisé, l'une avec une expérience de plantation d'arbres de 10 ans avec du bouleau et du pin près de Bordeaux (expérience ORPHEE), la seconde le long d'un gradient latitudinal de forêts de hêtres matures dans les Alpes françaises (expérience BIOPROFOR).Les résultats obtenus montrent que les racines de bouleaux et de pins présentaient une distribution verticale similaire et une biomasse souterraine similaire de racines dans les mélanges d'arbres par rapport aux monocultures, contrairement à ma première hypothèse. Cependant, l'attribution plus importante du pin mais pas du bouleau à la croissance des racines dans les horizons du sol supérieur dans des conditions moins limitatives en eau suggère des conditions localement favorables qui peuvent conduire à une compétition asymétrique à la profondeur du sol. De plus, la production et la décomposition des racines fines étaient similaires dans les mélanges et dans les monocultures, en contradiction avec ma deuxième hypothèse. Il est intéressant de noter que les racines de bouleau, mais pas les racines de pin, ont libéré du P pendant leur décomposition, ce qui suggère un rôle important du bouleau dans le cycle du P et pour la nutrition en P des arbres sur ces sols sableux limités en P. Conformément à ma troisième hypothèse, j'ai observé une décomposition plus lente de la litière de feuilles et des racines fines en réponse à une sécheresse estivale prolongée, tout au long du gradient latitudinal dans les Alpes. Cependant, cette décomposition plus lente sous la sécheresse n'a pas été atténuée dans les peuplements forestiers à essences mixtes par rapport aux peuplements à essences uniques. Il est intéressant de noter qu’il y a une libération nette d'azote dans les racines fines en décomposition mais pas dans la litière de feuilles en décomposition, ce qui suggère un rôle distinct des racines fines dans le cycle de l'azote. En conclusion, j'ai constaté que le mélange des espèces d'arbres n'atténue pas les effets négatifs du changement climatique. Cette thèse démontre que la promotion de mélanges peut toujours être bénéfique pour au moins une des espèces d'arbres mélangées, par l'ajout d'espèces, car une espèce d'arbre peut en faciliter la nutrition minérale d’une autre par des flux souterrains de N et de P
The insurance hypothesis predicts that forests with tree species mixtures may resist better to stressful environmental conditions than forests composed of only one tree species. Most of the currently available literature tested this hypothesis for aboveground productivity and its related response variables, but less is known about belowground processes. In my PhD thesis, I studied the drivers of belowground productivity and decomposition across climatic gradients and how they are affected by tree mixtures. I hypothesized that mixing of tree species with contrasting rooting patterns and fine root morphologies, would result in a release of competitive pressure belowground, and translate into higher fine root standing biomass and increased fine root productivity. Moreover, I hypothesized that roots with contrasting chemical and morphological characteristics in mixed stands would decompose faster, which may be particularly important under nutrient-limited conditions. Under water-limiting conditions, such as during extreme summer drought, I hypothesized overall slower decomposition but an attenuating effect of tree mixtures on decomposition due to improved micro-environmental conditions, in particular for leaves, since roots decompose in a more buffered soil environment. To test these hypotheses I examined the variation in tree root functional traits (across- and within-species), and its consequences for fluxes of C, N and P at the ecosystem scale. I addressed three main objectives and associated research questions to quantify the interactive effect of tree mixtures and climate on: 1) vertical root segregation and fine root standing biomass, 2) fine root dynamics and their associated nutrient fluxes and 3) fine root- and leaf litter decomposition. I could benefit from two different field experiments for my work, one with a 10-year-old tree-plantation experiment with birch and pine close to Bordeaux (ORPHEE experiment), the second along a latitudinal gradient of mature beech forests in the French Alps (BIOPROFOR experiment).I observed that roots from the birch and pine tree-plantation showed similar vertical distribution and similar belowground root standing biomass in tree mixtures compared to monocultures, contrary to my first hypothesis. However, the greater allocation of pine but not of birch to root growth within the top soil horizons under less water-limiting conditions suggests locally favourable conditions that may lead to soil depth-specific asymmetric competition. In the same experiment, fine root production and decomposition were similar in mixtures and in monocultures, in contradiction with my second hypothesis. Moreover, I did not observe any interactive effects of tree mixtures with stand density or water availability. Interestingly though, birch roots, but not pine roots released P during root decomposition, which suggests an important role of birch in the P-cycle and for P nutrition of trees on these P-limited sandy soils. In line with my third hypothesis, I observed a slower decomposition of leaf litter and fine roots in response to reinforced and prolonged summer drought, irrespective of the position along the latitudinal gradient in the Alps. However, this slower decomposition under drought was not attenuated in forest stands with mixed tree species compared to single species stands. Compared to leaf litter, fine roots decomposed slower and released less C. Interestingly, I found a net N release in decomposing fine roots but not in decomposing leaf litter, which suggests a distinct role of fine roots in the N cycle. In conclusion, I found that mixing tree species did not attenuate negative effects of climate change. However, this thesis demonstrates that promoting mixtures can still be beneficial for at least one of the admixed tree species, through species addition (i.e., complementing one tree species with another tree species), as one tree species may facilitate another via belowground fluxes of N and P

Alexandrie, en tant que site de consommation antique, recevait des céramiques de provenances diverses mais dont les ateliers de production avaient acquis un degré d'organisation et un développement suffisants pour procéder à une diffusion à longue distance. Cette étude prend en compte plusieurs facteurs de connaissance des ensembles de céramiques issus des fouilles archéologiques du centre ville d'Alexandrie actuelle pour évaluer les importations (quantité, identité technique et identité culturelle, approche du commerce) en regard des fabrications locales. L'étude céramologique proprement dite a permis de déterminer les fabriques (ou ateliers) céramiques importées à Alexandrie et de connaître l'évolution de leur représentativité. Parallèlement, des analyses chimiques d'un échantillon des productions de certaines de ces fabriques ont permis d'identifier leur origine géographique. Cette démarche nous a conduit à faire le point sur les liens commerciaux entre Alexandrie et le reste de la Méditerranée : en précisant, d'un point de vue chronologique, l'apport, en terme de quantité et de qualité (degré technologique mis en œuvre), de chacun des centres producteurs qui exportent à longue distance. Dans un second temps, l'objectif a été de retracer l'évolution des productions d'un point de vue technologique et culturel et de confronter les données avec les facteurs économiques, notamment le fonctionnement du commerce. Enfin, on a cherché à appréhender les facteurs d'évolution de la production qu'ils soient culturels (évolution des formes de vases, adaptation, rejet) ou technologiques (revêtements noirs, revêtements rouges, absence de revêtement) de production. L'étude de ces ensembles céramiques s'est enfin appuyée sur des confrontations avec des faciès céramiques d'autres régions méditerranéennes aux mêmes époques afin de déterminer les caractères propres à la céramique fine d'Alexandrie tout en prenant soin de replacer ceux-ci dans leur contexte historique
In Alexandria, which was an important trade center in Antiquity, table ware were imported from many places. These wares came from workshops whose development and high level of organization allowed a large scale trading. Although the pottery workshops were numerous, those trading on a large scale were much fewer. This study deals with technical and cultural identity, quantity and provenance of fine wares found in Alexandria for approaching the question of trade. We also tried to assess at the part of the importations and the part of the local productions. The technical groups of production (called fabrics) and their respective quantity depending on the chronology were determined. A sample of sherds of some of the fabrics have been studied by chemical analysis aiming to find out the geographical provenience of these fabrics. All these investigations led us to precise our knowledge about the trading connections between Alexandria and the other Mediterranean lands. We also got new chronological indications concerning the quantity and the quality (technological level of the production) of each workshop producing and exportating pottery. We also tried to give a picture of the evolution of the production according to technological (black-glazed ware, red-glazed ware, ware without glaze) and cultural (evolution of shape, copy, disappearance, adaptation of shape) features and to compare these data with the trade mecanisms. Then, the Alexandrian series of fine pottery have been compared with other series from Mediterranean sites at the same period to determine Alexandrian specificities

Le lapis-lazuli fut la véritable pierre précieuse de l'orient ancien, signifiant symbolique essentiel du Proche-Orient et de l'Égypte, sa possession était un gage de puissance politique et religieuse. Son histoire, entamée dès le néolithique (au 7e millénaire), se prolonge à l’âge du bronze jusqu'au 2e millénaire av. J. -C. Et au-delà. Il est attesté sur des sites distants de plus de 3000 km, de l’Asie centrale à la Mésopotamie, et de la Syrie à l'Égypte. C'est une roche rare et difficile à se procurer car originaire de très hautes montagnes à l'accès restreint par les conditions naturelles. Le lapis-lazuli travaille dans l'orient ancien provenait des mines du Badakhshan (Afghanistan), du Gorno- Badakhshan au Pamir (Tadjikistan) et peut-être des monts de Chaghaï (Pakistan). Le lapis-lazuli connait son plus grand usage au milieu du 3e millénaire, les fabuleuses richesses des tombes du cimetière royal d'Ur en témoignent. L'étude des vestiges de fabrication et des outils indique l'existence d'une chaine commune de séquences opératoires pour la production des parures en lapis-lazuli. Des styles régionaux se sont différenciés selon qu'il s'agit de parures d'Égypte, de syro-Mésopotamie et de Susiane, ou bien d’Iran (hors l'Elam) ou encore d'Asie centrale. Les cités-états hiérarchisées de Syro-Mésopotamie étaient de grosses consommatrices de biens symboliques qui servaient aussi leur propagande. Les artisans travaillaient dans le cadre d'ateliers dépendants du palais ou des temples. L'épopée de Gilgamesh nous montre les dieux équiper de lapis-lazuli les êtres qu'ils veulent favoriser ou munir de protections avant l'entrée dans l'enfer. Le lapis-lazuli symbolise la force de vie qui est à la source de la puissance des dieux. Il est agent, signe et manifestation de la circulation de biens, d'idées et de représentations culturelles mais aussi des rapports d'influence, de domination et d'échanges entre les centres de civilisation du Proche-Orient du 4e au 2e millénaires av. J. -C
Lapis lazuli is considered as the real precious gem in the ancient near east, it was the most highly prized symbolic goods and being in possession of it was a gage of political and religious power. It is during the neolithic period 7th millennium bc) that its history begins; it goes on until the 2d millennium bc and beyond. The stone is found on sites which are more than 3000 km away from each other from central asia to mesopotamia, and from syria to egypt. This gem is scarce and very difficult to get because deposits are located in very high mountains with means of access limited by natural conditions. Lapis lazuli worked in ancient eastern came from Badakhshan deposits (Afghanistan), Gorno- Badakhshan in Pamir mountains (Tadjikistan) and perhaps from chaghai hills (Pakistan). Lapis lazuli use reached its zenith during the 3rd millennium; it is testified by the fabulous treasures of the graves excavated in the royal cemetery at ur. The study of beadmaking remains and tools reveals the existence of a common process of working phases to produce lapis lazuli jewellery. Regional styles appeared between ornaments from egypt, syria, mesopotamia and susiana, or iran (except elam) or even central asia. The state cities organised in hierarchy from syria and mesopotamia were great consumers of symbolic goods, which were usefil to their propaganda. Craftsmen worked in workshops that depended on palaces or temples, the gilgamesh epic tell us gods equipped with lapis lazuli the beings they wanted to favour or give protection to before entering hell. Lapis lazuli symbolises vital energy which is the origin of deity power. It is not only agent, sign and expression of the circulation of goods, of ideas and cultural representations but also of influence, domination and exchange relations between the near east civilisation centres from 4th till 2d millennia BC

Le procédé de broyage en voie humide est une opération intéressante permettant la production de particules fines ou de nanoparticules. La caractérisation de la taille des particules est une donnée essentielle pour l'interprétation des données, le contrôle et l'optimisation de ces procédés selon divers aspects. Il y a un manque de connaissances relatif à la caractérisation de la taille de particules en relation avec les procédés de broyage en voie humide. Cette caractérisation est spécifique pour différentes raisons. (i) Les dispersions traitées par broyage contiennent souvent des impuretés et (ou) des additifs. Nous savons assez peu comment les impuretés et les additifs influencent la taille des particules en suspension dans ces procédés. (ii) Lors de procédés de broyage en voie humide, des dispersions de différentes concentrations peuvent être utilisées. Il est important de savoir comment la concentration de la dispersion peut influencer la mesure de la taille des particules lors du procédé. (iii) La modification de la taille moyenne des particules, résultant de leur fragmentation, est rapide. (iv) Le degré de polydispersité dans le produit change au cours du temps. (v) La nature des interactions entre les particules change; avant broyage les particules sont non-colloïdales, elles le deviennent après un certain temps d'opération. De même, il y a un manque de connaissances permettant de comprendre comment la qualité du produit broyé final est affectée lors du broyage. Dans cette étude nous explorons plusieurs aspects de la caractérisation de taille et de la qualité du produit au cours d'un procédé de broyage en voie humide du CaCO3, réalisé à l'aide d'un broyeur à billes agité. La spectroscopie acoustique qui est une technique connue pour ses potentialités en matière de caractérisation de taille de dispersions en ligne, sous des conditions réelles de procédés et sans nécessiter une dilution des échantillons, a été utilisée dans cette étude en complément de la diffusion dynamique de la lumière. Ce travail a montré sous quelles conditions les effets des impuretés et des additifs etc. sur la taille des particules en suspension pouvaient être déterminés par spectroscopie acoustique. De plus, nous avons comparé et analysé les résultats des mesures de taille obtenus avec les deux techniques. Les différences observées ont été analysées. Nous avons montré que la diffusion multiple observée à forte concentration en solide lors des procédés de broyage en voie humide pouvait conduire à une mauvaise interprétation des résultats relatifs à la taille des particules. En outre, la qualité est un concept relatif. Dans ce travail, nous avons adopté une démarche pour mesurer les effets de différents paramètres sur les caractéristiques du produit broyé en se basant sur une définition de la qualité telle que dans la norme ISO 9000 :2005. La démarche a permis de prendre en compte différents paramètres opératoires importants (tels que les conditions de fonctionnement du broyeur, la mesure de la taille des particules et les propriétés du matériau), ainsi que différentes propriétés caractéristiques du produit (comme la taille moyenne des particules, la largeur de la distribution de taille, la stabilité de la dispersion, le taux d'impuretés, l'énergie spécifique apportée au système et l'apparence visuelle du produit). Nous avons montré que nous pouvions établir une relation entre les paramètres opératoires et différentes qualités de produits obtenus par un procédé de broyage en voie humide
Wet grinding process is an interesting means of producing fine and nano particles. The particle sizing plays an important role in interpretation, control and optimization of various aspects of the wet grinding process. There is a lack of knowledge in understanding different aspects of particle sizing during a wet grinding process. The particle sizing in a wet grinding process is typical in the sense: (i) The dispersions in a wet grinding process, often, involve additives and (or) impurities. It is less known how impurities and additives influence the particle size of the dispersions in the wet grinding process. (ii) In a wet grinding process, dispersions of different concentrations may be used. It is less known how dispersions of different concentration may influence the particle sizing in a wet grinding process. (iii) In a wet grinding process, the change in average particle size of the product is rapid due to relatively fast breakage of the particles. (iv) The degree of poly dispersity in product changes with grinding time. (v) The nature of interaction between particles is non-colloidal before grinding process; this interaction becomes colloidal after a certain grinding time. Similarly, there is a lack of knowledge to understand how quality of final ground product is influenced in a wet grinding process. This study investigates the different aspects of particle sizing and product quality of aqueous dispersions of CaCO3 in a wet grinding process carried out in a stirred media mill. Acoustic attenuation spectroscopy that is known for measuring particle size of dispersions on line, under real process conditions and without diluting the sample has been employed in the study in addition to the technique of dynamic light scattering. The study brings out the conditions in which the effects of impurities and additives etc. on particle size of the dispersions may be determined using acoustic attenuation spectroscopy. Furthermore, the study compares and analyze the particle sizing results obtained though acoustic attenuation spectroscopy and dynamic light scattering. The causes of differences in the results of two techniques have been investigated. We report presence of multiple scattering at high concentration of the dispersions during wet grinding process that result in misleading results of the particles sizes. Quality is an intangible concept. In order to understand how different operating parameters influence product quality, we propose a method based upon the definition of quality as defined in ISO 9000:2005. The method takes into consideration the important operating parameters of wet grinding process (such as the operating condition of the mill, the measurement of particle size and the material) and important product characteristics ( such as average particle size, range of width of particle size distribution, stability of dispersion, degree of impurities, specific energy input and physical appearance). We bring out how a relationship between operating parameters and products of different grades may be established in a wet grinding process

Le 5 janvier 1875 eut lieu à Paris l'inauguration du nouvel opéra, construit par l'architecte Charles Garnier. Ce dernier, partisan de l'architecture polychrome et passionne de mosaïques, avait réussi, non sans peine et avec l'aide du mosaïste italien Jean-Dominique Facchina (établi dans la capitale vers 1860), à recouvrir les plafonds de la loggia et de l'avant foyer de mosaïques d'email et les sols du théâtre de pavements en mosaïque de marbre. Ces travaux, inédits pour l'époque-puisque c'était la première fois que l'on faisait usage de la mosaïque de smalt à fond d'or pour la décoration d'un édifice public, remportèrent au cours de cette soirée inaugurale un triomphe stupéfiant, qui engendra aussitôt un phénomène de mode tout aussi spectaculaire. Des lors, et pendant plusieurs décennies, de nombreux architectes, adeptes de la polychromie, inclurent la mosaïque dans leurs programmes de décoration. C'est ainsi que les plus prestigieux édifices parisiens, profanes et religieux, privés et publics, bénéficièrent de décors en mosaïque, exécutés, en très grande majorité, dans l'atelier du maitre Facchina. Ce mosaïste, promoteur du renouveau de la mosaïque monumentale, dirigea jusqu'à sa mort (en 1903) le plus important atelier de mosaïque qui fut en France en cette fin de siècle et produisit une quantité incalculable d'ouvrages pour des commandes contractées dans le monde entier. Cet engouement extraordinaire pour ce genre de décoration favorisa également la création d'un atelier national et d'une multitude d'établissements prives, français et italiens, qui ont laissé, dans la capitale comme en province, d'importants ouvrages.

Includes bibliographical references.
The focus of this dissertation is the establishment of various entry-points into my practical project, Postproduction (2007 -2009). My project entails re-printing Nicolas Bourriaud's Postproduction (2007) with outdated and superseded printing technology, specifically letterpress/movable type. The text is printed onto paper that was handmade from original copies of Postproduction . Standard letterpress ink was used in combination with a Vandercook 219 AB press for the printing. To compensate for the occurrence of various complications and errors during the production process there were three to five working copies of the book. After a Single volume was selected for presentation in the gallery space all the remaining copies of the text were destroyed.

This work is an experimental and theoretical analysis of factors and conditions affecting smoke and carbon monoxide (CO) production in corridor-like enclosure fires. Thirty eight experiments were performed in a three metre long corridor-like enclosure having a cross section 0.5 m x 0.5 m, door-like openings in the front panel and a propane gas burner located near the closed end. Measurements of smoke and carbon monoxide concentrations were performed at locations inside the enclosure and also in the exhaust duct of a hood collecting the combustion products. The main conclusion of this work is that smoke production depends not only on the fuel and Global Equivalence Ratio (GER) - as is reported in the literature - but also on the temperatures and residence time inside the enclosure, at least for the experimental conditions examined in this study. Additionally, it was found that the smoke concentration inside the enclosure was increasing during the ventilation controlled regime even after external burning started. Such increase was verified by temperature, smoke and velocity measurements inside the enclosure. The increase was due to reverse flow behind the flames travelling along the corridor. Namely, the gases reversed direction behind the flames with hot gases travelling in the upper layer backwards towards the closed end of the corridor in contrast to hot gas movements towards the opening in front of the flames. This recirculation was confirmed by velocity and oxygen concentration measurements in the upper and lower layers inside the enclosure. In addition, the present results show that the relationship reported in the literature between smoke and carbon monoxide production during overventilated conditions yco/ys ≈ constant, is no longer valid during an underventilated enclosure fire. The ratio yco/ys increases for the Global Equivalence Ratios of the enclosure greater than one. The obtained results are useful for CFD validation and specifically applicable for assessing smoke hazards in corridor fires in buildings where smoke concentrations can be much larger than anticipated owing to leakage to adjacent rooms behind travelling flames.

Ce travail s'inscrit dans le cadre de la modelisation et de l'evaluation quantitative des performances de systemes complexes de production a flux discrets par modeles a reseaux de files d'attente (rfa). Nous nous interessons plus particulierement a deux classes de systemes de production: les systemes flexibles de production (sfp) et les architectures multiprocesseurs (am) multibus avec blocages des memoires. Le developpement et l'exploitation d'un sfp posent des problemes relevant d'horizons temporels differents (niveaux strategique, tactique et operationnel), et qui sont reconnus comme tres difficiles. Les industriels recherchent donc des methodes et des outils qui permettent une evaluation quantitative des performances d'un sfp, en particulier pour l'etude des problemes rencontres aux niveaux strategique et tactique. Un etat de l'art montre non seulement la richesse du formalisme des rfa, mais aussi son adequation pour aider a resoudre ces problemes. Cependant, l'obtention des caracteristiques d'un modele a rfa exploitable sur calculateur, a partir des donnees des industriels, est un probleme qui n'a pas ete resolu de maniere satisfaisante. En effet, l'exploitation ad hoc de ces donnees conduit a un nombre prohibitif de chaines et de classes de clients, excluant de facto toute resolution par approches analytiques et/ou numerique. Dans ce contexte, nous proposons des elements de reponse qui s'appuient sur: une vision systemique d'un sfp qui aide a maitriser la complexite d'un sfp lors de la specification de sa structure et de son fonctionnement, une formalisation de la charge d'un sfp exploitee pour definir un processus systematique d'agregation des donnees de la charge ; et qui fournit, de maniere transparente a un industriel, les caracteristiques exactes d'un modele a rfa soluble par methodes analytiques et/ou numerique. Nous montrons l'applicabilite et la qualite de nos resultats sur un sfp industriel de type job-shop avec blocages en transfert des machines, modelise par un rfa resolu par chaines de markov et approche analytique. Bien que les am multibus aient ete largement etudiees par modeles a rfa, la prise en compte d'une indisponibilite temporaire des memoires exclut, a priori, le developpement de tels modeles a forme produit. Dans ce contexte, nous proposons, dans le cas ou les memoires sont systematiquement bloquees apres chaque acces, un modele markovien exact a rfa, plusieurs modeles markoviens approximatifs agreges, et deux approches analytiques approximatives. La qualite et la robustesse des approches approximatives sont etablies experimentalement

Les alginates sont des polysaccharides naturels extraits des macro-algues brunes, et disponibles en quantités quasi-illimitées à bas prix. En présence de cations divalents ou par diminution de pH, ces polymères renouvelables ont la capacité de former instantanément des hydrogels, que l’on peut ensuite transformer en solvogels et aérogels, caractérisés par de grandes surfaces spécifiques, de bonnes propriétés mécaniques, une bonne résistance à une large gamme de solvants organiques et une manipulation aisée. Ces dernières années, les gels d’alginate ont été utilisés comme supports d’espèces chimiques actives en catalyse hétérogène, ainsi que comme catalyseurs acides de Brønsted. Dans ce contexte, le présent travail contribue à élargir l’utilisation des gels d’alginate à la catalyse hétérogène asymétrique, en exploitant les propriétés particulières de ces biomatériaux. Dans la première partie de cette étude, les billes de gel d’acide alginique ont été utilisées comme support pour préparer une version hétérogène d’un catalyseur chiral homogène, dérivé de la quinine, pour l’addition de Michael asymétrique. Contrairement aux approches classiques d’immobilisation de catalyseurs par liaison covalente, notre approche consiste à immobiliser l’organocatalyseur par simples interactions non-covalentes. Les résultats présentés ici montrent que l’adsorption du catalyseur, une base de Lewis organique, se produit avec d’excellents rendements sur les gels d’acide alginique en utilisant un protocole très simple et tout à fait reproductible. Les billes d’organocatalyseur chiral supporté sont actives comme catalyseurs hétérogènes dans l’addition de Michael d’aldéhydes sur les nitroalcènes, permettant l’obtention du produit attendu avec de bons rendements et de bonnes diastéréosélectivités et énantiosélectivités. Dans cette réaction, les fonctions acides carboxyliques du biopolymère agissent à la fois comme co-catalyseur acide et comme site d'ancrage non covalent pour le catalyseur amine tertiaire. L’utilisation de gels hétérocationiques, formés par l’échange partiel de protons par des cation alcalino-terreux, ont permis pour cette réaction d’obtenir des catalyseurs avec une meilleure tenue mécanique, une plus grande porosité, menant ainsi à de plus grandes activités catalytiques. Dans un second temps, les gels d’alginate ont aussi été utilisés comme un moyen possible de transférer la chiralité du support alginate à un produit de réaction sans l’aide d’un inducteur chiral. La réaction de Friedel-Crafts des nitroalcènes avec les indoles a été choisie comme réaction modèle pour évaluer l’énantio-induction éventuelle de métaux de Lewis supportés sur gels d’alginate. La librairie de catalyseurs testée est active dans la réaction. Les catalyseurs comprenant du cuivre et du Baryum ont montré une bonne activité et surtout ont permis de prouver l’effet inducteur chiral du support, puisqu’un excès énantiomérique modéré est obtenu. De plus, ces deux métaux donnent chacun accès majoritairement aux deux énantiomères possibles, ce qui est un résultat important puisque l’alginate ne présente qu’un seule forme énantiomérique. Le choix du métal pourrait donc orienter l’obtention de l’un ou l’autre des énantiomères. La nature hétérogène de ces catalyseurs est prouvée en utilisant les gels au Cu, et la recyclabilité du système est également montrée puisqu’une perte très faible d’activité et une conservation de la stéréosélectivité sont observées sur cinq cycles réactionnels. Ce travail représente la première utilisation des gels d’alginate comme supports de catalyseurs pour l’organocatalyse chirale, et le premier exemple d’induction chirale par le support alginate uniquement pour une réaction de couplage C-C d’intérêt pour la chimie fine
Alginates are natural polysaccharides extracted from brown macro-algae, available in nearly unlimited amounts at very low prices. In the presence of some divalent metals or by lowering the pH, these renewable biopolymers can readily form hydrogels, solvogels and aerogels, characterized by high surface areas, good mechanical properties, tolerance to different media, and easy manageability. In the last years, alginate gels have been gradually used as supports for a varied range of active chemical species in heterogeneous catalysis and as solid acid Brønsted catalyst. In this context, the present work contributes to broaden the use of alginate gels in asymmetric heterogeneous catalysis, exploiting the peculiar features of this class of natural biomaterials. In the first part of this study, the use of alginate gel beads as supports to prepare a heterogenized version of an amino Cinchona alkaloid for asymmetric Michael addition is described. In contrast with the classical immobilization via covalent attachment in oil-derived support, our approach was the immobilization of the organocatalyst using non-covalent interactions. The results presented here demonstrate that the adsorption of a representative Lewis base organic catalyst (9-amino-9-deoxy epi-quinine, QNA) takes place with high yields onto acidic alginate gels (AGs) using a very simple and straightforward protocol. This protocol is robust and fully reproducible. The resulting chiral solvogel beads (QNA@AGs) are active as heterogeneous catalysts in the addition of aldehydes to nitroalkenes, affording the corresponding adducts in good yields and moderate to excellent diastereo- and enantio-selectivities. In these reactions, the carboxylic functions of the biopolymer act as both acidic co-catalyst and non-covalent anchoring site for the tertiary amine catalyst (as observed by IR spectroscopy). The use of heterocationic gels, derived from alkaline earth metal gels by partial proton exchange, provided materials with better mechanical properties and higher porosities, ultimately resulting in higher catalytic activities. The alginate gels were also assessed as a possible way of transfering chirality from the support to a reaction outcome. The Friedel-Crafts alkylation of nitroalkenes with indoles was selected as a model reaction to evaluate preliminarily the enantio-induction by metal Lewis alginate gels. The library of alginate gels tested is active in the benchmark reaction. The Cu and Ba- alginate gels afford good activity and the enantiomeric-induction is proved, obtaining moderate enantiomeric excesses under the optimized reaction conditions. Furthermore, these two metals allow access to both enantiomers of the products, an important aspect given that only one enantiomeric form of alginates is available. Finally, the heterogeneous nature of the catalyst is proved using Cu-alginate gels. The full recyclability is demonstrated, by showing that Cu-alginate gels can be recovered and recycled without loss of stereochemical activity for at least five reaction cycles. This work represents the first utilization of alginates, abundant and renewable biopolymers, as gel supports/media for asymmetric organocatalytic processes and the first example of induction of enantioselectivity for a C-C bonding reaction with interest in the fine chemical industry

Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第11615号
農博第1471号
新制||農||905(附属図書館)
学位論文||H17||N4008(農学部図書室)
23258
UT51-2005-D364
京都大学大学院農学研究科地域環境科学専攻
(主査)教授 武田 博清, 教授 二井 一禎, 教授 東 順一
学位規則第4条第1項該当

Devising new photocatalysts that can harvest light energy to drive chemical processes is in the forefront of chemical research. It aims at limiting the use of depleting fossil fuel energy, better understanding optical properties of materials and developing green chemical synthesis processes. During this doctoral work, three different types of photocatalysts, based on titanium dioxide, gold nanoparticles and vanadium clusters, have been designed and evaluated for synthetically important organic chemical reactions under visible light irradiation at near ambient conditions.

El delta del Paraná conforma una unidad diferenciada de su entorno: la selva de rivera. Sufre periódicas inundaciones como consecuencia del desborde de los ríos o por la sudestada que provoca el ingreso de las aguas del Río de la Plata en dirección contraria a su escorrentía natural. El sector interno de las islas presenta una capa freática cercana a la superficie y el perfil de los suelos es una sucesión de capas de diferente espesor y granulometría. En cambio en las partes altas se ha desarrollado un horizonte superficial, característico de los molisoles. Actualmente el principal destino de los suelos es forestal o ganadería extensiva estacional pero, es posible que en un futuro, debido a la creciente demanda de alimentos sean acondicionadas para fines agrícolas. El objetivo del presente trabajo es el de analizar las principales limitaciones  de los suelos' presentes en el delta argentino y cartografiarlos a escala 1:500000 a nivel de unidad cartográfica. Las limitantes estudiadas fueron la textura superficial y subsuperficial, salinidad, alcalinidad, drenaje y peligro de anegamiento. Se utilizaron los datos presentes en la cartografía de suelos a escala 1:500000 y l: 200000.   The Delta of Parana conforms a different unit of its surrounding environment : the shore jungle. It's a zone characterized by several and frecuent inundations as consequence of rivers overflow or by south east wind which causes the Río de la Plata water to enter in opposite direction to its natural flow. The islands internal area presents a phreatic layer near the surface and the si de view soils have several layers of different thickness and granulometric types. Otherwise, a shallow soil horizon has developed at high sectors, mainly characterized by mollisels. At present, main land use is forestry or livestock, but in the future it's posible to prepare the soil for agricultúral purposes, because of food demand m crease. The objetive of this paper is to analize the main limitations of present soils in the Argentinian delta and map them with 1:500000 scale as a cartographic unit. Studied limitations were: surface and undersurface texture, alkalinity, salinity, drainage and overflowing. Present data were used in soils cartography with scale 1:500000 and 1:200000.

Le but de cette these est l'etude theorique et l'implementation numerique de la methode des volumes finis associee a la discretisation des flux dans une base mixte pour des problemes d'evolution non lineaires intervenant dans des problemes lies a l'extraction d'hydrocarbures. Nous etudions tout d'abord un modele diphasique faisant intervenir deux lois de conservation pour l'huile et pour l'eau que nous discretisons de deux facons differentes : tout d'abord, nous reprenons une methode souvent utilisee qui consiste a transformer le probleme en une loi de conservation pour une saturation couplee a une equation elliptique pour la pression ; nous discretisons la loi de conservation a l'aide de la methode des volumes finis tandis que nous appliquons la methode de elements finis mixtes ou mixtes hybrides pour le calcul de la pression. Nous proposons ensuite une nouvelle methode qui consiste a discretiser les deux lois de conservation a l'aide de la methode des volumes finis tandis que nous calculons le gradient de la pression a l'aide d'une base mixte. Cette methode a l'avantage de pouvoir s'etendre au cas general ou il n'est pas possible de transformer le systeme en une equation d'evolution en saturation couplee a une equation elliptique en pression. Nous demontrons ensuite la convergence de la methode numerique dans le cas d'un systeme lineaire hyperbolique-elliptique ou l'on discretise l'equation elliptique par la methode des elements finis mixtes et la loi de conservation par celle des volumes finis ; ce systeme est un cas particulier des deux formulations du modele diphasique considere plus haut. La demonstration de convergence s'appuie sur un principe de maximum discret et sur une inegalite de type bv-stable. Nous discutons ensuite l'implementation effective de la methode pour un modele compositionnel huile-gaz appele encore modele black oil ou sont pris en compte des phenomenes de vaporisation, de dissolution, de compressibilite et d'heterogenite. Il s'avere que cette methode numerique peut etre appliquee dans le cas ou le tenseur de permeabilite est heterogene et anisotrope, ce qui represente un cas difficile que les ingenieurs des milieux petroliers ne savaient pas bien aborder jusqu'a present. Nous considerons finalement le cas ou la pression capillaire est presente et nous discretisons les termes de diffusion a l'aide de la base mixte. Les resultats obtenus sont satisfaisants si la pression capillaire n'est pas trop importante.

Les ateliers flexibles multi-objectifs de chimie fine sont mis en uvre pour elaborer, a faibles tonnages, des gammes variees de produits a forte valeur ajoutee. Leur fabrication, impliquant de nombreuses etapes de synthese, est soumise a des contraintes strictes relatives, d'une part, a l'instabilite du marche (duree de vie courte, fluctuation de la demande) et, d'autre part, a des normes rigoureuses sur la qualite et la protection de l'environnement. Dans ce contexte, une gestion efficace de tels ateliers doit concilier les performances locales des operations unitaires et la performance globale de l'atelier. Ce memoire propose differentes strategies de resolution de ce probleme a travers une methodologie a trois volets. La premiere phase concerne le developpement d'un modele de simulation a evenements discrets pour representer le fonctionnement global de l'atelier au cours du temps et determiner la faisabilite de l'ordonnancement. Il integre les principales caracteristiques du domaine de la chimie fine. Toutefois, son ecriture en langage oriente-objet, c++, a pour but de le rendre adaptatif a d'autres applications. La deuxieme etape est relative a la definition de protocoles operatoires et a permis de determiner, a travers un exemple, une strategie de recyclage pour minimiser tant la consommation des matieres premieres que le rejet d'effluents. Cette phase implique la modelisation de certaines operations unitaires afin de definir leurs conditions d'exploitation. Le couplage du simulateur d'atelier avec une procedure d'optimisation par algorithme genetique permet ensuite de resoudre efficacement le probleme de planification au caractere combinatoire tres marque. Trois cas de figure sont traites : maximisation de la production pour un fonctionnement par campagnes cycliques, maximisation de la production d'une seule campagne a horizon fini, minimisation des delais. Dans tous les cas, un gain significatif est obtenu par rapport a une recherche manuelle par essais-erreurs.

La céramique à paroi fine est un groupe de vaisselle romaine parmi les plus représentés sur les sites archéologiques. Un échantillonnage important (environ 25000 fragments) a été mis au jour dans les différents secteurs fouillés de la cité étrusco-romaine de Musarna (territoire de Tarquinia). Son étude a permis d'identifier cinquante-huit formes de vases et de retracer leur évolution technique. Leur comparaison avec le matériel provenant des sites voisins, de l'Étrurie, de toute la péninsule italique, et des territoires conquis a conduit à l'identification de plusieurs zones de production. Divisés en six phases chronologiques, leur datation s'étend entre le dernier tiers du IIe siècle av. J.-C. et le IIe siècle ap. J.-C
The Thin-walled ware is one of the most represented class of vessel ceramic found on roman archaeological sites. An important batch (around 25000 shards) has been found in the various areas explored in one of the etrusco-roman cities of Tarquinia's territory: Musarna. The study of that Corpus allowed us to identify fifty-eight forms of vases and to trace their technological evolution. The parallels found with the material coming from others sites in Etruria, in the whole Italy and in the conquered territories have evidenced the existence of several productions areas. The Thin-walled ware from Musarna can be divided in six chronological phases, distributed between the last third of the II century B.C. and the II century A.D

My project is an exploration of process within the painting medium, themed round my experiences of 'self' and community, as located in my past and present circumstances. Throughout my work, my intention has been to explore my social, personal and political 'beliefs' in order to create a body of paintings that both reflects and challenges my 'belief' structures. In my work there are contradictory desires for change and stability, and an ongoing struggle between location and dislocation.

This PhD by Publication is a contribution to art and art theory through the book Art and Value in the context of the practice of the Freee art collective. This thesis situates Art and Value within contemporary art practices and debates. Art and Value addresses itself directly to misrecognitions of the relationship between art and capitalism within the humanities and social sciences. The conviction that art was a commercial activity had penetrated the discourses of contemporary art in the UK, Western Europe and North America since the 1960s and therefore constituted, in part, the milieu in and against which Freee has operated since 2004. The historical study of the emergence of the theory of art’s economic exceptionalism in classical political economy gives an alternative historical framework in which to situate the discussion of art’s relationship to capitalism. The rationale for my economic analysis of art – comprising separate critiques of the economics of art in classical, neoclassical, welfare and Marxist economics – is to reset the coordinates for thinking politically about art’s relationship to capitalism. Art and Value does not claim to cover every aspect of art’s encounter with capitalism, which would require sociological, semiotic, psychoanalytic, geographical, philosophical and historical inquiries, at the very least, but establishes the economic groundwork for the interdisciplinary study of art’s relationship to capitalism. Economic analysis provides this ground; not because economics is the master discipline of the social sciences, but because the question of art’s relationship to capitalism must be understood, first and foremost, by understanding what capitalism is and how the production of art has or has not been incorporated into the capitalist mode of production.

El presente Estudio de Caso describe el desarrollo de la política de incentivo a las plantaciones forestales con fines productivos en Colombia, y evalúa su desempeño a través de la eficacia del Programa “Certificado de Incentivo Forestal” de reforestación (CIF). Analiza además, aspectos relevantes de su diseño y gestión para el periodo 1994 –2007. Para hacer esta investigación se analizó información actualizada de fuentes primarias y secundarias sobre el sector forestal colombiano. Así mismo, para efectuar la evaluación de eficacia fue necesario realizar una reconstrucción a nivel de antecedentes y de resultados del Programa, pues éste contó con un diseño de acuerdo con una metodología de formulación. En este sentido, este proceso se adelantó tomando elementos fundamentales de la metodología de Marco Lógico y particularmente de la estructura de evaluación de programas gubernamentales, utilizada por Ministerio de Hacienda de Chile. El CIF es el principal instrumento económico del Gobierno colombiano orientado a promover la forestación con fines comerciales en el país. Éste se materializa mediante la entrega por cinco años de una compensación a los productores, equivalente a un porcentaje de sus costos de plantación y mantenimiento, como reconocimiento por su participación en una actividad que genera externalidades positivas; para este caso, servicios ambientales. Así, se busca motivar el incremento sostenible de la superficie forestada, la mayor producción de servicios ambientales y el aumento de la competitividad. Los resultados obtenidos indican que el desempeño del Programa a nivel de eficacia no ha sido satisfactorio, y que su contribución al cumplimiento de las metas de largo plazo se encuentra por debajo de lo esperado, al ser la herramienta gubernamental más importante para fomentar esta actividad. Lo anterior, teniendo en cuenta el enorme potencial forestal de Colombia sustentado en 25 millones de hectáreas (has) de suelos de aptitud forestal y en el hecho que existe la meta de plantar 1,5 millones de has. para el año 2025. Sin embargo, desde su creación en 1994 hasta el 2007, solamente fueron forestadas 220.679 has. en todo el país; de estas, el 57,3% fueron efectuadas a través del CIF, lo que equivale al 8,34% de la meta asignada. Estas cifras demuestran que aunque el CIF ha logrado mantener una dinámica de forestación, representada en una inversión estatal de USD 45 millones para el periodo de análisis, esta no ha sido significativa para contribuir a hacer de Colombia un país competitivo y líder en materia forestal. Lo anterior es producto de múltiples factores que han afectado su desempeño a nivel de eficacia y eficiencia. A nivel de diseño, se evidenció falta de focalización del fin y propósito del Programa CIF, hoy orientados a cumplir múltiples objetivos en lo social, ambiental y productivo. Así mismo, a nivel de gestión, se constató la inexistencia de un presupuesto fijo para financiarlo y su gran variabilidad de una vigencia a otra. En esta misma línea, también se verificaron dificultades relacionadas con el control de la gestión, asociadas a la ausencia de un sistema de seguimiento y evaluación de los proyectos. Así, aunque se evidencia que se han realizado importantes ajustes a su operatividad y focalización, al orientarse a la consolidación de Núcleos Forestales competitivos y al concentrar cada vez más su gestión en el Ministerio de Agricultura, se concluye que el Estado debe comprometerse aún más en generar las condiciones que propicien el cumplimiento de los logros definidos en su diseño. Este sentido, se recomienda revisar y priorizar sus objetivos, mejorar la focalización y acotar las metas de acuerdo a la capacidad institucional existente; aumentar y ser más eficiente en uso del presupuesto e incrementar el liderazgo del Ministerio en la implementación y evaluación del Programa. Lo anterior enfocado a mejorar la satisfacción de los beneficiarios, para que esto se traduzca en una mayor y mejor superficie forestada, que genere los beneficios ambientales y económicos esperados.

This work investigates the computer modelling of the photochemical formation of smog products such as ozone and aerosol, in a system containing toluene, NOx and water vapour. In particular, the problem of modelling this process in the Commonwealth Scientific and Industrial Research Organization (CSIRO) smog chambers, which utilize outdoor exposure, is addressed. The primary requirement for such modelling is a knowledge of the photolytic rate coefficients. Photolytic rate coefficients of species other than N02 are often related to JNo2 (rate coefficient for the photolysis ofN02) by a simple factor, but for outdoor chambers, this method is prone to error as the diurnal profiles may not be similar in shape. Three methods for the calculation of diurnal JNo2 are investigated. The most suitable method for incorporation into a general model, is found to be one which determines the photolytic rate coefficients for N02, as well as several other species, from actinic flux, absorption cross section and quantum yields. A computer model was developed, based on this method, to calculate in-chamber photolysis rate coefficients for the CSIRO smog chambers, in which ex-chamber rate coefficients are adjusted by accounting for variation in light intensity by transmittance through the Teflon walls, albedo from the chamber floor and radiation attenuation due to clouds. The photochemical formation of secondary aerosol is investigated in a series of toluene-NOx experiments, which were performed in the CSIRO smog chambers. Three stages of aerosol formation, in plots of total particulate volume versus time, are identified: a delay period in which no significant mass of aerosol is formed, a regime of rapid aerosol formation (regime 1) and a second regime of slowed aerosol formation (regime 2). Two models are presented which were developed from the experimental data. One model is empirically based on observations of discrete stages of aerosol formation and readily allows aerosol growth profiles to be calculated. The second model is based on an adaptation of published toluene photooxidation mechanisms and provides some chemical information about the oxidation products. Both models compare favorably against the experimental data. The gross effects of precursor concentrations (toluene, NOx and H20) and ambient conditions (temperature, photolysis rate) on the formation of secondary aerosol are also investigated, primarily using the mechanism model. An increase in [NOx]o results in increased delay time, rate of aerosol formation in regime 1 and volume of aerosol formed in regime 1. This is due to increased formation of dinitrocresol and furanone products. An increase in toluene results in a decrease in the delay time and an increase in the rate of aerosol formation in regime 1, due to enhanced reactivity from the toluene products, such as the radicals from the photolysis of benzaldehyde. Water vapor has very little effect on the formation of aerosol volume, except that rates are slightly increased due to more OH radicals from reaction with 0(1D) from ozone photolysis. Increased temperature results in increased volume of aerosol formed in regime 1 (increased dinitrocresol formation), while increased photolysis rate results in increased rate of aerosol formation in regime 1. Both the rate and volume of aerosol formed in regime 2 are increased by increased temperature or photolysis rate. Both models indicate that the yield of secondary particulates from hydrocarbons (mass concentration aerosol formed/mass concentration hydrocarbon precursor) is proportional to the ratio [NOx]0/[hydrocarbon]0

Dans des filières à haut degré de diversité et de renouvellement des produits, il est très difficile d'établir des lois économiques permettant de prévoir avec précision le coût dès la phase de conception. Pourtant c'est à ce stade que sont définis 70 à 80% des coûts d'un produit, mais on dispose d'une information très limitée et souvent relative aux caractéristiques esthétiques ou fonctionnelles du produit. Il s'avère donc essentiel pour les concepteurs d'avoir un outil d'estimation adapté et flexible afin d'optimiser les décisions en conception et de minimiser le risque de rejet du produit. Nous avons retenu l'approche basée sur la méthode paramétrique des Formules d'Estimation des coûts (FEC). D'abord, nous définissons une méthodologie générale pour le développement des FEC spécifiques, en intégrant les contraintes lors de la conception d'un produit, puis nous avons expliqué les concepts des principales techniques pour le développement des FEC, comme les techniques de régression et celles issues du " soft computing ". En particulier nous avons développé un modèle Hybride Neuro-flou Simplifié permettant, une meilleure interprétation des interrelations entre variables notamment dans des systèmes complexes. En autre, un outil permettant de développer une FEC avec ces différentes techniques simultanément et de comparer plusieurs FEC en termes de précision, robustesse, pertinence et capacité d'adaptation, est proposé afin de soutenir le processus de conception. Il permet d'avoir un maximum de visibilité en simultané des diverses FEC candidates. Cette approche a été testée sur un exemple d'application, dans le domaine de l'impression textile pour développement d'une FEC spécifique
In supply chains with high degree of product diversity and renewal, there is very difficult to establish economical laws at the design stage, in order to accurately forecast product cost. Nevertheless at this early stage, product cost is defined by 70 to 80% but also, only scarce product information is available, related mainly to product aesthetical features or functionalities. In order to minimise the risk of product reject, it is important for designers to have a cost estimation tool, flexible and easy to adapt. We use the parametric approach in order to develop Cost Estimation Relationships (CER's). First, we define a general methodology and main concepts in order to develop CER's as regression and softcomputing techniques. In particular we developed a Simplified Hybrid Neuro-Fuzzy model, allowing better variables interpretation, mainly for complex systems. Also, we proposed a tool in order to develop a CER by using the described modelling techniques. The candidates CER's could be compared in terms of accuracy, robustness and relevance. This tool allows a maximum of information in order to choose the best CER. This approach has been tested on a particular case concerning the development of specific CER for a textile printing industry

Un systeme flexible de production peut etre modelise par reseau de files d'attente. Nous faisons une synthese de travaux recents sur le developpement de modeles analytiques, et nous presentons de nouveaux modeles. Les modeles de quatrieme et cinquieme chapitres peuvent etre qualifies de modeles simplifies, puisqu'ils ne prennent en compte qu'un seul type de synchronisation: un nombre limite de palettes (au quatrieme chapitre), ou la capacite limitee du systeme automatise de transport (au cinquieme chapitre). Nous analysons des modeles complexes en utilisant une methodologie de decomposition au sixieme chapitre. L'evaluation est faite a la fois par methodes analytiques et par methode markovienne. Nous pouvons ainsi analyser des synchronisations type "rendez-vous". . . .

For all kinds of paperboard packages, the bending stiffness of the paperboard is a crucial property. In multi-ply folding boxboard (FBB) grades, this is obtained by placing different stocks in the outer and centre plies of the board. In the outer plies, a stock with a high tensile stiffness is used, typically made from refined kraft pulp fibres. In the middle ply/plies a stock with more bulky properties is placed, typically comprising of a high proportion of CTMP (chemi-thermomechanical pulp). CTMP fibres are stiffer and more inflexible with poor bonding abilities resulting in low strength properties. To increase the bonding strength in the middle ply, broke, containing chemical pulp is added, and sometimes refined chemical kraft pulp as well. Both fibres and fines, i.e. smaller fibre fragments, in a pulp have a significant contribution to the properties of the product. Fines produced during refining of chemical pulp are especially beneficial for increasing the strength. To achieve pulp fraction with higher fines content the pulp can be fractionated with a micro-perforated screen basket; a fine fraction produced from a screen with very small holes will contain a large proportion of fines. By adding such a fine fraction to a middle ply stock, the bulk properties of the main pulp, for example a CTMP, can be conserved as less refining of this pulp is required to achieve the targeted strength properties. However, a drawback is that the fine fraction usually has a very low mass concentration after the screening process as a lot of water pass through the screen together with the fines and fibre fragments. The excess water must be removed to maintain the water balance of the papermaking process. Further, the larger volumes require extra pumping capacity. A resource-efficient production of a fine fraction must target a high fine fraction mass concentration and a high content of fines and short fibre fragments in order to be implemented industrially. The focus of the present work was on separation efficiency (i.e. the difference in fibre length distribution caused by screening) and process efficiency (i.e. the concentration of the fine fraction) for production of a fine fraction of chemical pulp by screening, and the utilisation of the fine fraction as strength agent. Pilot-scale fractionation trials with a pressure screen with different microperforated screen baskets were performed in order to evaluate how the separation efficiency and process efficiency were affected by parameters such as feed concentration, pulp type (hardwood or softwood kraft pulp), hole size of the screen, and refining treatment prior to screening. The trials were evaluated using fibre length distributions, flow rates and concentrations of viii the feed flow and the fractions. Here, two complementary quantitative measures, Proportion in fine fraction (for process efficiency) and Fine fraction enrichment (for separation efficiency), were developed. To evaluate the strength enhancing effect of the obtained fine fraction, a lab scale study was performed where the fine fraction of a highly refined pulp was compared with the highly refined pulp as strength agent for a CTMP. The results of this study were verified in a pilot paper machine trial. In a second pilot paper machine trial, sheets with different CTMP proportions in the middle ply were studied in order to find out if the bulk could be increased while maintaining strength, by using a fine fraction made from refined chemical pulp. Regarding process efficiency, it was found that the most important parameter to obtain a high fine fraction concentration was a high feed concentration. Further, a higher fine fraction concentration for a given screening process was also obtained when using hardwood pulp and refining the pulp prior to the screening process. A higher feed concentration also had a positive effect on the separation efficiency. Small holes and a smooth surface of the screen basket were also important to improve the separation efficiency. It was shown that, when used as a strength agent in a CTMP pulp, the fine fraction of highly refined kraft pulp was twice as efficient as the highly refined kraft pulp, when added at equal mass proportion. However, both in the lab and pilot trial the strength increase was accompanied by a decreased bulk. This was expected, and to avoid this the proportion of the bulky CTMP had to be increased. The pilot paper machine trial with an increased CTMP proportion in the middle ply and a fine fraction of refined kraft pulp as strength agent demonstrated that it was possible to produce sheets with an increased bulk and maintained z-strength.
Böjstyvheten är en viktig egenskap för alla sorters hårda förpackningar. I flerskiktskartong får man böjstyvhet genom att ha ytterskikt med hög dragstyvhet tillverkade av fibrer från kemisk massa och ett mittskikt med hög bulk från styva fibrer, ofta med en stor andel CTMP (kemitermomekanisk massa). CTMP-fibrer är styva men ger lägre styrka i arket. För att öka styrkan i mittskiktet tillsätter man utskott (kasserad kartong) som delvis innehåller kemisk massa, och ibland även ren högmald kemisk massa. Både fibrer och finmaterial (fines) har stor betydelse för slutproduktens egenskaper. Fines som skapas vid malning av kemisk massa är särskilt effektiva för att öka styrkan. Genom att fraktionera massa med en mikroperforerad sil kan man få en finfraktion med högt finesinnehåll. Mikroperforerade silar är effektiva för längdfraktionering av massa; fines anrikas i den fraktionen som passerar silen medan långa fibrer stannar i den andra fraktionen. Genom att använda en sådan finfraktion i mittskiktet kan man få tillräcklig styrka och samtidigt behålla mer av bulken från CTMP:n genom att man inte behöver mala den för att få styrka. En nackdel är att finfraktionen vanligtvis har väldigt låg masskoncentration eftersom mycket vatten passerar silen tillsammans med fines och fiberfragment. Detta extra vatten måste tas bort för att vattenbalansen i papperstillverkningsprocessen ska bibehållas. Dessutom kräver den större volymen ökad pumpkapacitet. För att kunna använda en finfraktion industriellt behövs en effektiv produktion med hög koncentration och högt finesinnehåll. Fokus i det här arbetet lades på separationseffektivitet (skillnaden i fiberlängdsfördelning som resultat av silningen) och processeffektivitet (koncentrationen i finfraktionen) för tillverkning av en finfraktion av kemisk massa genom silning samt dess utnyttjande som styrkehöjande tillsats i ett mittskikt av kartong. För att utvärdera hur separationseffektiviteten och processeffektiviteten påverkas av parametrar som koncentrationen i flödet in till silen, typ av kemisk massa (gjord av lövved eller barrved), hålstorlek i silen samt malningen av massan, gjordes fraktioneringsförsök i pilotskala med en trycksil med olika mikroperforerade silkorgar. Resultatet av fraktioneringen utvärderades med hjälp av fiberlängdsfördelningar, flöden och koncentrationer i flödet till silen och de två fraktionerna efter silen. För utvärderingen togs två olika utvärderingsmetoder fram: Proportion i finfraktionen (för processeffektivitet) och Finfraktionsanrikning (för x separationseffektivitet). För att utvärdera hur effektiv en finfraktion av kemisk massa var som styrkeadditiv i ett CTMP-ark gjordes labbförsök där tillsats av högmald kemisk massa jämfördes med tillsats av enbart en finfraktion av den högmalda kemiska massan. Resultaten verifierades med ett försök på en pilotpappersmaskin. I ett följande försök på pilotpappersmaskinen tillverkades ark med ökat CTMP-innehåll för att öka bulken, och med en tillsats av en finfraktion av kemisk massa som styrkeadditiv. När det gäller processeffektivitet var hög koncentration i flödet till silen den viktigaste parametern för att få hög koncentration på finfraktionen. Detta var också positivt för separationseffektiviteten, färre av de längre partiklarna hamnade i finfraktionen. Vidare blev finfraktionens koncentration högre för lövvedsmassa. En finfraktion som ska användas som styrkeadditiv ska vara tillverkad av mald massa, malning av massan var också fördelaktigt för finfraktionens koncentration. Små hål och en slät yta på silkorgen var också positivt för separationseffektiviteten. Som styrkeadditiv i CTMP var finfraktionen av högmald kemisk massa dubbelt så effektiv som den högmalda kemiska massan vid lika stor tillsats. Men i både labbförsök och pilotförsök minskade bulken när styrkan ökade. Det var väntat eftersom att ersätta en del av originalmassan som har hög bulk, med en finfraktion eller högmald massa, som båda har mycket lägre bulk, alltid minskar bulken på arket. För att undvika en bulkförlust måste massasammansättningen i arket ändras. Försöket på pilotpappersmaskinen med ökat CTMP innehåll och en finfraktion av mald kemisk massa som styrkeadditiv visade att det är möjligt att tillverka ett ark med högre bulk och bibehållen styrka.

The Building Breathes Together presents a realm of speculative, industrial habitation and alchemical production. In my instillation, I look to raise questions surrounding romantic notions of production and utility. The work introduces a surreal and haunted space of decomposition and regeneration.

The present investigation analyzed early second language (L2) learning in adults. A common finding regarding L2 acquisition is that early learning appears to be necessary in order to perform on the same level as a native speaker. Surprisingly, many current theoretical models posit that the human ability to learn novel speech sounds remains active throughout the lifespan. In light of this fact, this project examines L2 acquisition in late learners with a special focus on L1/L2 use, input, and context of learning. Research regarding L1/L2 use has tended to be observational, and throughout the previous six decades of L2 research the role of input has been minimized and left largely unexplained. This study includes two production experiments and two perception experiments and focuses on the role of L1/L2 use and input in L2 acquisition in late learners in order to add to current research regarding their role in accurately and efficiently acquiring a novel speech sound. Moreover, this research is concerned with shedding light on when, if at all, during the acquisition process late learners begin to acquire a new, language-specific phonetic system, and the amount of exposure necessary in order to acquire L2 fine-phonetic detail. The experimental design presented in the present study also aims to shed light on the temporal relationship between production and perception with regard to category formation. To begin to fully understand these issues, the present study proposes a battery of tasks which were administered throughout the course of a domestic immersion program. Domestic immersion provides an understudied linguistic context in which L1 use is minimized, target language use is maximized, and L2 input is abundant. The results suggest that L2 phonetic category formation occurs at an early stage of development, and is perceptually driven. Moreover, early L2 representations are fragile, and especially susceptible to cross-language interference. Together, the studies undertaken for this work add to our understanding of the initial stages of the acquisition of L2 phonology in adult learners.

Le travail de these propose d'integrer les notions de niveaux d'information aux questions classiques de gestion et conception. Lorsque le contexte est celui d'une grande diversite, une solution permettant un bon compromis entre diversite offerte et delai d'obtention d'un produit fini est l'assemblage a la commande. Nous proposons des methodes d'aide a la mise en place de cette politique. En effet, quand le choix de strategie de production a ete effectue en faveur de cette politique, il faut repondre a la question suivante: comment la mettre en place en utilisant au mieux l'information partielle disponible? cette derniere question souleve deux problemes, le choix des produits semi-finis a pre-assembler et le dimensionnement des stocks ainsi definis. Notre travail permet la prise en compte de differents niveaux d'information qui peuvent etre accessibles. Cette etude s'attache aussi a mettre en lumiere et a quantifier l'avantage que constitue une connaissance plus precise de la demande des produits finis. Pour cela, nous avons determine:-une formalisation de l'information sur la demande en produits finis est proposee. Elle introduit une notion de hierarchisation de l'information. -une demarche permettant la construction, a partir de l'information disponible, d'une information sur la demande en produit finis s'appuyant sur l'entropie est proposee. -des heuristiques permettant de choisir les produits semi-finis a stocker-une demarche d'etude pour le dimensionnement d'exemples didactiquesnous avons ainsi propose des methodes permettant de determiner des solutions aux deux questions soulevees. Les tests nous ont egalement permis d'illustrer la valeur de l'information
This phd thesis addresses the problem of the set-up of a stock policy adapted to a huge diversity context. We propose to include the notion of information levels into the classical question of design and inventory management. When product diversity enlarges, choosing an assemble to order policy offers a good compromise between product portfolio size and assembly lead time. We propose methods to help set up this policy. Actually this implementation raises the following question: how to make the set-up using the available information. This question can be split up in two: how to choose the modules to stock ? how to size stocks ? huge diversity also has a powerful impact on information. Therefore, our work enables to take into account different information levels. This study also aims at observing the advantage of information on final products demand. Therefore we : - model information about demand with an hierarchical point of view- develop an entropy-based method to construct information about final demand from available information- propose heuristics for the choice of modules- study the inventory problem on didactical examplesby those means we propose methods to deal with the two questions of ato set-up. Thanks to tests, we also stress the value of information

Le travail de cette thèse, en partenariat entre l'UPMC et CGGVeritas, consiste en l'étude de faisabilité théorique du suivi CSEM du déplacement latéral de l’interface huile/eau au sein d’un réservoir terrestre avec un dispositif permettant d'obtenir l'information sur la répartition des fluides sur une grande surface. Après un état des lieux des méthodes géophysiques appliquées au suivi de réservoir d'hydrocarbures, une présentation de la théorie sur les algorithmes de simulation est donnée (Méthode des Moments et différences finies). Le développement est plus approfondi pour la Méthode des Moments. Le dispositif qui a montré la meilleure sensibilité consiste en un dipôle source vertical enterré à mi-profondeur entre le réservoir et la surface, et des récepteurs horizontaux de champ électrique posés à la surface. Le niveau du signal 4D, i. E. La différence de champ mesuré à deux instants différents, reste légèrement au dessus du bruit ambiant que l'on peut éliminer par sommation. L’inversion 4D a montré la possibilité d'interpréter les données synthétiques CSEM en utilisant une seule position de source et une grille de récepteurs posés à la surface. Les images tirées de ces essais d'inversion font bien ressortir l'interface huile/eau. La non prise en compte d'une couche fine d'une dizaine de mètres, avec un fort contraste de résistivité par rapport à l'encaissant, est pratiquement sans effet sur le signal mesuré directement à la surface, mais réduit la résolution de la frontière huile-eau lors de l'inversion 4D. Une bonne connaissance de la distribution de conductivité électrique de l'ensemble du terrain environnant reste donc nécessaire à l'inversion de données CSEM 4D
Low frequency electromagnetic methods from a controlled source (CSEM : Controlled Cource ElectroMagnetic) have been applied for a little more than a decade in oil exploration. As a complement to seismic methods, they permit lowering of the risk of «dry holes», since they are more sensitive to the nature of the uid contained in rock. Because of the numerous successes encountered, and experience acquired, petroleum companies foresee extending application of CSEM to the monitoring of reservoirs under production. The principal problems are monitoring the oil-water interface to avoid loss of production due to invasion by water, and to estimate the e_ciency of improved techniques on the recovery rate for production (EOR : Enhanced Oil Recovery). The interface of oil and water is subject to an essentially lateral displacement due of low thickness of hydrocarbon reservoirs having an area that exceeds several square kilometres. The work of this thesis, done in partnership between UPMC and CGG Veritas, consists of the theoretical feasibility of monitoring CSEM for the lateral displacement of oil-water interface with a n apparatus that permits obtaining information on the distribution of uids for a large surface reservoir. We are particularly interested in the land milieu. After an examination of the status of applied geophysical methods on the monitoring for hydrocarbon reservoirs, a presentation of the theory of simulation algorithms is made. For this thesis, two codes have been developed, parallelized and used on parallel machines for which the calculation grid is European, EGEE. The _rst uses the semi-analytic Method of Moments for the frequency domain, and by extension, for the time domain. The second is based on _nite di_erence for the time domain. The development is more concentrated on the Method of Moments (code : EM MOM). The EM MOM code was able to be tested during a cooperative mission with CIPR (Center for Integrated Petroleum Research) at the University of Bergen, Norway. The code permitted doing a sensitivity analysis in the frequency domain to identify device geometries better adapted to the monitoring of a hydrocarbon reservoir (depth of 1000 meters). The apparatus that yields the greatest sensitivity consists of a vertical dipole source buried at mid depth between the top of the reservoir and the ground surface, and of horizontal receptors for electrical _eld set on the ground surface. The level of 4D signal, i. E. , the di_erence of measured _eld at two di_erent instants («time lapse») remains at a level slightly over the ambient noise, which can largely be eliminated by summation (vertical stacking). A series of measures of ambient noise done by CGGVeritas, presented in the _rst part of this thesis, establishes this observation. A 4D inversion algorithm has demonstrated the possibility of interpreting the synthetic CSEM data by using a single position of source, and an array of receivers positioned on the surface. The images drawn from the inversion trials show the oil-water interface very well. The neglect of a narrow layer of a dozen meters having a strong contrast in conductivity with the terrain environment, is practically annulled for the signal measured at the surface, but reduces the resolution of the oil-water boundary in 4D inversion. A high level of knowledge of the distribution of electrical conductivity for the entire terrain environment is therefore necessary for the inversion of 4D CSEM data. Iv

L'allergie respiratoire au pollen de bouleau affecte un nombre important de personnes dans le monde. Il est estimé que 100 millions d'individus sont sensibilisés à l'allergène majeur du pollen de bouleau nommé Bet v 1. L’immunothérapie allergénique, basée sur l'administration répétée de l'allergène incriminé, permet la rééducation du système immunitaire du patient d’un profil TH2 vers un profil TH1/Treg et à terme la diminution des symptômes allergiques. Ces travaux de thèse avaient donc pour finalité de produire et de caractériser l'allergène recombinant Bet v 1, à des fins d’immunothérapie allergénique. Dans ce cadre, différentes méthodes analytiques ont été développées et appliquées afin d'optimiser le procédé de production via l'élimination de différentes impuretés liées au produit ou au procédé de production et de documenter la structure de l’allergène. En particulier, l'utilisation de la spectrométrie de masse a permis la détermination de la masse exacte de l'allergène ainsi que la vérification complète de sa séquence en acides aminés. Les travaux en spectrométrie de masse ont également contribué aux détections et identifications de diverses impuretés et produits de dégradations et ont ainsi conduit à plusieurs optimisations du procédé industriel de production de l'allergène recombinant. Les activités immunologiques de certains produits de dégradations ont également été investiguées. La structure tertiaire (spatiale) de l'allergène a été déterminée par diffraction aux rayons X. Enfin, ces travaux ont permis de documenter la qualité de l'allergène recombinant rBet v 1 afin i) de l'établir comme substance de référence pour la Pharmacopée Européenne et ii) de procéder à une étude clinique d’immunothérapie allergénique de phase II auprès de 483 patients allergiques au pollen de bouleau
Respiratory allergy to birch pollen affects a large number of people in the world. It is estimated that 100 million people are sensitized to the major allergen from birch pollen, namely Bet v 1. Allergen immunotherapy, based on the repeated administration of the allergen of interest, allows the modification of the patient's immune response from a TH2 to a TH1/Treg pattern and thus the reduction of allergic symptoms. This study was therefore aimed to produce and characterize the recombinant Bet v 1 (rBet v 1) allergen, for immunotherapy purpose.In this context, various analytical methods have been developed and applied in order to optimize the production of rBet v 1 via the reduction of process or product-related impurities as well as to document the quality of the purified allergen. In particular, the use of mass spectrometry has allowed the determination of the exact mass of the intact allergen and the complete verification of its amino acid sequence. Mass spectrometry data have also contributed to the detection and identification of impurities and degradation products and have therefore led to several optimizations of the industrial process for the production of the recombinant allergen. Immunological activities of certain degradation products were also investigated and the allergen tertiary structure was determined by X-ray diffraction. Finally, this study was decisive in order i) to establish rBet v 1 as a chemical reference substance for the European Pharmacopoeia as well as ii) to perform a phase II clinical study conducted in 483 patients with birch pollen-induced rhinoconjunctivitis

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O Gerenciamento das Restrições (GR) parte do pressuposto de que a meta de qualquer empresa é ganhar mais dinheiro no presente, bem como no futuro. A Teoria das Restrições é um conjunto de soluções embasadas na Teoria do Caos, que busca o desempenho global do sistema, pela gestão de seus poucos recursos críticos. Esta teoria é aplicada a qualquer empresa, já que estas, por natureza, têm característica sistêmica. O objetivo deste trabalho é avaliar a implantação da metodologia Tambor-Pulmão-Corda com Supermercado, resultante da Teoria das Restrições, na gestão do planejamento e programação de produção, nas unidades de fabricação de eletrodos de grafite da Graftech International Ltd., situadas em Candeias e Monterrey, no período de 2001 a 2004. Projeto piloto, aplicando esta metodologia, foi desenvolvido por um grupo de técnicos da Empresa e, posteriormente, foi aprovado para ser implantado nas demais unidades do grupo. A estratégia de pesquisa adotada foi o estudo de casos. Como resultados da implantação do modelo TPC com Supermercado, temos uma linguagem uniforme de planejamento e programação de produção entre as unidades estudadas e a Corporação, tendência de redução do nível de inventário e o entendimento comum de como gerir as restrições físicas a partir das cinco etapas da Teoria das Restrições: Identificar, explorar, subordinar, elevar e identificar a nova restrição. Por fim, chegamos à conclusão de que o modelo proposto não pode ser dado como implantado em nenhuma das duas unidades estudadas, e que as maiores dificuldades encontradas estão atreladas às restrições não físicas, principalmente no que se refere às políticas de vendas/marketing, contabilidade de custos e busca dos resultados de curto prazo.
Salvador

A cafeicultura é uma atividade agrícola histórica e tradicional no Brasil e que passa atualmente por uma reformulação em função das novas exigências qualitativas e sociais no mercado internacional. A importância da qualidade do café reside em atender o gosto do consumidor e em representar um fator bastante específico para sua apreciação. As características físicas e organolépticas da bebida do café são influenciadas pelos manejos pré e pós-colheita da cultura. Nesse contexto, a demanda por cafés finos torna necessário que os sistemas de produção adotem novas tecnologias, de manejo e gerenciais, que permitam o aumento da produtividade e a obtenção de um produto com elevada qualidade. O incremento da complexidade no setor torna maior a responsabilidade do produtor perante suas decisões administrativas, incentivando-o a buscar novas ferramentas de análise. A modelagem matemática apresenta-se como um auxílio nas tomadas de decisões cuja aplicação em problemas de otimização na agricultura é bem sucedida. Nesse sentido, esta dissertação tem como objetivo a otimização do gerenciamento de uma propriedade agrícola voltada para a produção de cafés. Para tanto, foi realizado um estudo de caso na Fazenda Santa Maria da Boa Vista, localizada no município de Cristais Paulista (SP), cujos dados empíricos da produção de café auxiliaram na elaboração e validação de um modelo matemático para a otimização da produção de cafés finos. Tal modelo matemático de programação linear multiobjetivo, composto por uma função multiobjetivo, três conjuntos de restrições contábeis, sete conjuntos restrições técnicas e dois conjuntos de variáveis endógenas, se mostrou capaz de auxiliar no planejamento da produção da propriedade, na programação do seqüenciamento de colheita das lavouras, determinando o volume ótimo de produção de cafés finos.
Coffee production is a historical and traditional agricultural activity in Brazil which is going through a reformulation due to new qualitative and social demands in the international market. The importance of quality to coffee resides in attending the consumer needs and in representing a specific factor for price determination. The physical and organaleptic characteristics of coffee drinks are influenced by pre and post-harvest management of the culture. In this context the demand for special coffee makes it necessary to adopt new technologies to the production systems, to manage the culture and its administration, which allow increase in productivity and a product with good quality. This elevation in complexity within the coffee chain increases the importance given to the farmer\'s administration decisions, stimulating him to search for new supporting tools for analysis. Mathematical modeling presents itself as an assisting tool to decision making with successful applications in agriculture. Therefore, this study aims to optimize the management of a coffee farm. A case study was conducted at the farm Santa Maria da Boa Vista, located in Cristais Paulista district in the State of São Paulo. The production data of the farm was used to elaborate and validate the mathematical model for special coffee production optimization. This linear programming multiobjective model with one multiobjective function, three sets of countable restrictions, seven sets of technical restrictions and two sets of endogenous variables presented itself as capable of assisting in the farms production planning, in the determination of the harvest sequencing and of the optimal volume of special coffee production.

Nanocelluloses are a very promising material that has been widely explored for the most diverse applications. The pursuit for sustainable and environmentally friendly materials is in line with the nature of nanocelluloses and therefore they have emerged as the perfect candidate for plastics substitution, food additive, rheology controller, 3D printing of diverse structures, among many other possibilities. This derives from their interesting characteristics, such as reduced size and high specific surface area, high tensile strength, crystallinity and transparency, and from the fact that, such as cellulose, they are obtained from renewable sources, with relative ease for functionalization in order to obtain desired specificities. It makes sense to explore their benefits in the papermaking industry, a sector that is becoming very competitive, with emerging research and development of new products with new interesting functionalities. The aim of the present thesis was to assess the interactions between nanocelluloses and the several paper components and their influence in the papermaking process and on the paper products quality. Considering that the work was conducted in straight cooperation with the national papermaking industry, the research was focused on the uncoated wood-free papers and nanocelluloses were used as furnish additive or at the paper surface as sizing or coating agent. Several goals were outlined, related with the difficulties/obstacles and challenges proposed by the industry, namely to a) improve the paper dry and wet-web strengths, b) increase mineral filler retention, c) reduce the softwood content, d) reduce the pulp refining energy, while controlling parameters such as drainability and process runnability when using nanocelluloses in the paper furnish, but also to e) improve printing quality when used at the papers’ surface. To fulfil the objectives proposed, different nanocelluloses were produced from a bleached eucalyptus kraft pulp, by using distinct production processes, which conferred specific properties to the final product. The isolation of the fibrils from the pulp was performed by intensive mechanical treatment and pre-treatments based on enzymatic hydrolysis, TEMPOmediated oxidation or carboxymethylation were previously conducted in order to facilitate the disruption of the structure. All of the production processes used were based on the existing literature. Besides, bacterial nanocellulose, which is produced from a bottom-up methodology, was also tested. The different nanocelluloses produced originated very different results when applied in papermaking. When used at the fibrous matrix, the study of their interaction with mineral fillers has revealed to be very important and therefore a thorough assessment of the calcium carbonate flocculation was performed through laser diffraction spectrometry. It was found that, depending on the nanocellulose characteristics, strong PCC flocs could be obtained. However, this was only possible in specific conditions, namely a) if a minimum level of fibrillation occurred during nanocellulose production, which was attained by pre-treating the pulp previously to mechanical isolation and b) by controlling the extent of chemical modification, as too high charge led to reverse flocculation. Besides, the extent of flocculation could be controlled by adjusting the nanocellulose characteristics, such as the degree of polymerization or charge. When added to papermaking furnishes, nanocelluloses generally confirmed their great potential as strength enhancer. The most promising samples were those produced from enzymatic hydrolysis, as they were able to accomplish all of the goals pursuit. Besides, it was found that they were able to substitute the requirements for common retention agents, emerging therefore as a green replacer for these synthetic polymers. As for the functionalized nanocelluloses, interesting outcomes were found. Firstly, a limit for the content of carboxyl groups of the samples was established, as too much charge and reduced fibrils size was found to be detrimental in papermaking. Secondly, due to their negative nature, it was found that they interact preferentially with the common cationic paper additives, and therefore, their reinforcing potential was only possible in the absence of these additives. The drainability of the process was always negatively affected by the nanocelluloses presence. However, some strategies to mitigate this problem, based on high-filler loadings, were implemented. Nanocelluloses were also used at the papers’ surface, as coating material or as additive in common sizing formulations, with the goal to improve the inkjet printing quality. Their ability to form strong entangled networks, very known for the film forming properties, was responsible for more closed paper structures, able to retain the ink pigments more effectively, increasing therefore printability. When combined with starch, an interesting synergy was found and the results revealed that the addition of 5% of nanocellulose to sizing formulations was able to significantly improve the end-users color perception. In conclusion, the nanocellulose influence in the production process and final properties of fine papers was assessed and it was found that this new material can be produced in such a way that the industry requirements are fulfilled. Besides, a new commercial bioproduct, produced from the industry’s main raw material and with relevant potential applications was explored. In this sense, the paper industry will be not only improving its final product, but also adding value to one of the intermediate materials.
As nanoceluloses são um material com imenso potencial, tendo vindo a ser exploradas para as mais diversas aplicações. A procura por materiais sustentáveis e amigos do ambiente está em linha com a natureza das nanoceluloses e portanto, estas têm surgido como o candidato perfeito na temática crucial da substituição dos plásticos, ou como aditivo na indústria alimentar, controlador reológico, para impressão 3D de diversas estruturas, entre muitas outras possibilidades. As suas peculiares propriedades, tal como reduzido tamanho e elevada área de superfície específica, bem como o potencial para elevada resistência mecânica, cristalinidade e transparência, combinadas com o facto de, tal como a celulose, provir de fontes renováveis e ter relativa facilidade de funcionalização, são os principais responsáveis pela elevada procura das nanoceluloses. Faz assim todo o sentido o seu uso na indústria do papel, um sector cada vez mais competitivo com uma forte componente de investigação e desenvolvimento de novos produtos afins com interessantes funcionalidades. A presente tese pretende explorar a influência das nanoceluloses no processo produtivo e na qualidade final de produtos papeleiros. O objectivo principal foi o de estudar as interacções entre estes novos nanomateriais e os diferentes componentes do papel. Uma vez que o trabalho foi efectuado em estreita cooperação com a indústria papeleira nacional, o plano experimental focou-se nos papéis finos de impressão e escrita e as nanocelulose foram adicionadas como aditivo na produção do papel ou à superfície deste, como agente de revestimento ou aditivo em formulações de colagem superficial. Estabeleceram-se assim vários objectivos, concordantes com as dificuldades identificadas e desafios propostos pela indústria, nomeadamente a) melhorar a resistência a seco e a húmido do papel, b) aumentar o conteúdo de cargas minerais, c) reduzir o conteúdo de fibra longa, d) reduzir a energia de refinação da pasta, controlando ao mesmo tempo parâmetros processuais como drenabilidade, quando se usam as nanoceluloses na produção do papel, mas também e) melhorar a qualidade de impressão quando usadas à superfície deste. Por forma a cumprir os objectivos propostos, pasta kraft de eucalipto branqueada foi usada para produzir diferentes tipos de nanocelulose com base em distintos processos de produção que conferiram propriedades específicas. O isolamento das fibrilas foi efectuado com recurso a tratamento mecânico intensivo, aplicando-se previamente tratamentos de hidrólise enzimática, oxidação mediada por TEMPO ou carboximetilação para facilitar a desestruturação dos materiais. De referir que todas as metodologias usadas se basearam na literatura existente. Para além disso, nanocelulose produzida por síntese bacteriana também foi testada. As diferentes nanoceluloses produzidas deram origem a diversos resultados quando aplicadas na produção de papel. Ao serem usadas na matriz fibrosa revelou-se de extrema importância o estudo das suas interacções com as cargas minerais e neste sentido efectuou-se uma análise detalhada dos processos de floculação de carbonato de cálcio por recurso a espectrometria de difracção laser. Foi possível produzir flocos de PCC, cujas características dependem das nanoceluloses usadas. Para tal, concluiu-se ser necessário a) ocorrer fibrilação aquando da produção das nanoceluloses, o que foi possível quando se pré-tratou a pasta antes do isolamento mecânico e b) controlar a extensão da modificação química, uma vez que uma carga demasiado elevada conduziu ao reverso da floculação. Para além disso, o processo de floculação pôde ser controlado pelo ajuste das características das nanoceluloses usadas, nomeadamente o seu grau de polimerização e carga. Ao serem adicionadas à matriz fibrosa, as nanoceluloses melhoraram de uma forma geral as resistências mecânicas. As amostras com maior potencial revelaram ser as produzidas com recurso a hidrólise enzimática, uma vez que permitiram alcançar todos os objectivos propostos. Ademais, pelo seu uso, foi possível substituir a necessidade de uso de agentes de retenção comuns, emergindo assim como um substituto ecológico destes aditivos sintéticos. Relativamente às nanoceluloses funcionalizadas, foi também possível obter resultados interessantes. Por um lado, foi possível estabelecer um limite ideal para o conteúdo de grupos carboxílicos, uma vez que uma carga demasiado elevada ou um tamanho de fibrilas muito diminuto demonstraram ser prejudiciais na produção de papel. Por outro lado, concluiu-se que, devido à sua carga altamente negativa, estas interagem preferencialmente com os aditivos papeleiros, que são catiónicos, e portanto o efeito de reforço foi apenas conseguido na ausência dos referidos aditivos. A drenabilidade do processo foi sempre afectada negativamente na presença das nanoceluloses. No entanto, apresentaram-se algumas estratégias baseadas no aumento do conteúdo de cargas minerais, que podem ajudar a reduzir esta limitação. Finalmente, as nanocelulose foram adicionadas à superfície do papel, seja como agente de revestimento ou como aditivo a formulações de colagem superficial, com o intuito de melhorar a qualidade de impressão. A conhecida capacidade de estabelecer fortes redes interligadas levou a uma estrutura papeleira fechada, capaz de reter os pigmentos da tinta de forma mais eficaz. Adicionalmente, quando combinadas com amido, revelaram estabelecer uma relação sinergística muito interessante e pela adição de 5% de nanoceluloses foi possível melhorar consideravelmente a qualidade de impressão. Conclui-se assim que as nanoceluloses podem ser produzidas de forma a satisfazer as necessidades da indústria papeleira. De salientar que este é um novo bioproduto com potencial de mercado, produzido a partir da matéria-prima principal deste sector produtivo. Desta forma, não só a indústria papeleira estará a melhorar a qualidade do produto final, mas também a acrescentar valor a um dos seus produtos intermediários.
The Navigator Company

Thesis (Ph. D.)--Chemical Engineering, Georgia Institute of Technology, 2008.
Committee Chair: Dr. Christopher Jones; Committee Member: Dr. Dennis Hess; Committee Member: Dr. Hang Lu; Committee Member: Dr. Marcus Weck; Committee Member: Dr. Pradeep Agrawal. Part of the SMARTech Electronic Thesis and Dissertation Collection.