Beeswax organogels: Influence of gelator concentration and oil type in the gelation process

This work focused on how different types of oil phase, MCT (medium chain triglycerides) and LCT (long chain triglycerides), exert influence on the gelation process of beeswax and thus properties of the organogel produced thereof. Organogels were produced at different temperatures and qualitative phase diagrams were constructed to identify and classify the type of structure formed at various compositions. The microstructure of gelator crystals was studied by polarized light microscopy. Melting and crystallization were characterized by differential scanning calorimetry and rheology (flow and small amplitude oscillatory measurements) to understand organogels' behaviour under different mechanical and thermal conditions. FTIR analysis was employed for a further understanding of oil-gelator chemical interactions. Results showed that the increase of beeswax concentration led to higher values of storage and loss moduli (G, G) and complex modulus (G*) of organogels, which is associated to the strong network formed between the crystalline gelator structure and the oil phase. Crystallization occurred in two steps (well evidenced for higher concentrations of gelator) during temperature decreasing. Thermal analysis showed the occurrence of hysteresis between melting and crystallization. Small angle X-ray scattering (SAXS) analysis allowed a better understanding in terms of how crystal conformations were disposed for each type of organogel. The structuring process supported by medium or long-chain triglycerides oils was an important exploit to apprehend the impact of different carbon chain-size on the gelation process and on gels' properties.

A elite política parlamentar portuguesa: caracterização, cristalização e circulação (2005-2011)

Dissertação de Mestrado em Ciência Política

Potentially viable solar powered appliances cooling and distillation

Stand alone solar powered refrigeration and water desalination, two of the most popular and sought after applications of solar energy systems, have been selected as the topic of research for the works presented in this thesis. The water desalination system based on evaporation and condensation was found to be the most suitable one to be powered by solar energy. It has been established that highoutput fast-response solar heat collectors used to achieve high rates of evaporation and reliable solar powered cooling system for faster rates of condensation are the most important factors in achieving increased outputs in solar powered desalination systems. Comprehensive reviews of Solar powered cooling/refrigeration and also water desalination techniques have been presented. In view of the fact that the Institute of Technology, Sligo has a well-established long history of research and development in the production of state of the art high-efficiency fast-response evacuated solar heat collectors it was decided to use this know how in the work described in this thesis. For this reason achieving high rates of evaporation was not a problem. It was, therefore, the question of the solar powered refrigeration that was envisaged to be used in the solar powered desalination tofacilitate rapid condensation of the evaporated water that had to be addressed first. The principles of various solar powered refrigeration techniques have also been reviewed. The first step in work on solar powered refrigeration was to successfully modify a conventional refrigerator working on Platen-Munters design to be powered by highoutput fast-response evacuated solar heat collectors. In this work, which was the first ever successful attempt in the field, temperatures as low as —19°C were achieved in the icebox. A new approach in the use of photovoltaic technology to power a conventional domestic refrigerator was also attempted. This was done by modifying a conventional domestic refrigerator to be powered by photovoltaic panels in the most efficient way. In the system developed and successfully tested in this approach, the power demand has been reduced phenomenally and it is possible to achieve 48 hours of cooling power with exposure to just 7 hours of sunshine. The successful development of the first ever multi-cycle intermittent solar powered icemaker is without doubt the most exciting breakthrough in the work described in this thesis. Output of 74.3kg of ice per module with total exposure area of 2.88 m2, or 25.73kg per m2, per day is a major improvement in comparison to about 5-6kg of ice per m2 per day reported for all the single cycle intermittent systems. This system has then become the basis for the development of a new solar powered refrigeration system with even higher output, named the “composite” system described in this thesis. Another major breakthrough associated with the works described in this thesis is the successful development and testing of the high-output water desalination system. This system that uses a combination of the high-output fast-response evacuated solar heat collectors and the multi-cycle icemaker. The system is capable of producing a maximum of 141 litres of distilled water per day per module which has an exposure area of 3.24m2, or a production rate of 43.5 litres per m2 per day. Once again when this result is compared to the reported daily output of 5 litres of desalinated water per m per day the significance of this piece of work becomes apparent. In the presentation of many of the components and systems described in this thesis CAD parametric solid modelling has been used instead of photographs to illustrate them more clearly. The multi-cycle icemaker and the high-output desalination systems are the subject of two patent applications.

Heterogene Prozesse am Beispiel der Verbrennung fester Stoffe und der Kristallisation aus Lösungen

Heterogeneous processes, solids, combustion, crystallization, kinetics, online-monitoring, gaspotentiometric oxygen sensors, chiral separation, solid/liquid equilibria

Einfluss der Mikrokonvektion auf Selektivität und Stofftransport während der Verdunstung binärer Flüssigkeiten aus porösen Schichten

Interfacial convection, enhancement of mass transfer, packed beds, evaporation, selectivity

Untersuchungen zum Einfluss des Gegenenantiomers bei der enantioselektiven Kristallisation aus Lösungen

Enantioseparation, enantioselective crystallization, structurally related impurity, counter enantiomer, crystallization kinetics, crystal growth, chiral purity, crystal shape, mandelic acid, threonine

Modeling and simulation of population balances for particulate processes

This work focuses on the modeling and numerical approximations of population balance equations (PBEs) for the simulation of different phenomena occurring in process engineering. The population balance equation (PBE) is considered to be a statement of continuity. It tracks the change in particle size distribution as particles are born, die, grow or leave a given control volume. In the population balance models the one independent variable represents the time, the other(s) are property coordinate(s), e.g., the particle volume (size) in the present case. They typically describe the temporal evolution of the number density functions and have been used to model various processes such as granulation, crystallization, polymerization, emulsion and cell dynamics. The semi-discrete high resolution schemes are proposed for solving PBEs modeling one and two-dimensional batch crystallization models. The schemes are discrete in property coordinates but continuous in time. The resulting ordinary differential equations can be solved by any standard ODE solver. To improve the numerical accuracy of the schemes a moving mesh technique is introduced in both one and two-dimensional cases ...

Envelhecimento das aguardentes

1 - Colour, by itself, does not constitute a solid ground for judging of the age of a brandy because the more or less pronounced colour it acquires through aging can also be obtained by the addition of oack essence to newly distilled brandy. 2 - Urder the same conditions, colour intensity of a brandy wiU depend upon the nature of the wood and the condition of the storage. 3 - In accordance with the experimental results obtained by the present writers it rests no doubt that fermentation facility ferment resistence, produce and quality of the brendy all are factors depending upon the variety of the sugar cane. In addition, the authors presume that the variety of sugar cane has also influence upon the alteration of composition of the brandy submitted to aging. 4 - All aging phenomena of the brandy are accompanied by volume decreasing, what happens in a slow and continuous manner depending upon storage and environment conditions 5 - During brandy aging the alcoholic degree is greatly af- fected by evaporation, increasing or decreasing in accordance to the hygrometric state of the air and the teriperature in the place where the tuns are stored. 6 - The specific weight of the brandy is inversely proportio- nal to its alcoholic degree, but directly proportional to the extracts since the latter indicates the amount of dissolved residues. 7 - Brandy which shows high specific weight together with high alcoholic degree cannot be considered as aged. It may, however, be takens for brandy artificially coloved in order to conceal its actual age. 8 - The amount of extracts increases with aging, since it is the result of the solvent action of the brandy upon the soluble extractive substances of the wood. Notwithstanding that the extract, considered alone, has no value in determining the age of a brandy, since nothing easier is ohan to nake it change artificially. 9 -During aging the brandy get acidity in physiological as well as in physical way, but never by the action of microorganisms. 10 - The estturs produced during aging by the action of acids upon alcohols are the mean factors of the savour (bouquet) of a brandy and therefore every thing shall be done tor fhr estherification of a preserved brandy being not limited. 11 - Aeration increases esther formation, reduces the aging- time and turn better the taste qualities of the brandy. 12 - Due to the great proportion of high alcohols ordinarily found in the brandy, their analytical discrimination will be greatly important. 13 - The high alcohols are not responsable for the disastrous consequences of the alcoholism, but the high percentage of uthyl alcohol present in the brandy. 14 - The aldehydes appear always in high rate in the brazilian brandys in consequence of some intermediary products of the oxydation of the alcohols being left in the brandys during aging. 15 - The age has little or no influence on the quantity of phurphurol present in a brandy whose amount varies greatly the manner in which the wines to be distilled are treated. Wines centrifugalized or filtered before distillation always give rise to brandys poorer in phurphurol as compared with those distilled without these treatments. 16 - Though greatly variable, brandys of good qualities generally show a high residues coefficient, never under 200 mmg 17 - Lusson - Rocques oxydation coefficient cannot be indis- criminately applied to any brandy class, being, on the contrary, specifically destined to cognacs.

Lactacidemia: métodos de dosagem do ácido lático

A critical study of three methods for the determination of lactic acid (EDWARDS, MENDEL & GOLDSCHEIDER, MILLER & MUNTZ) is presented and some modifications are proposed. It was shown t hat more accurate results could be obtained with Edward's technic when an Iena glass filter is connected with the absorption tube. Before the dropping of the permanganate solution it is necessary to pass a current of air through the reaction flask to avoid the oxidation of the non-lactic acid substances which interfere with the reaction. The absorption tube must be maintained at 18°C during the destillation and the titration of the bisulphite binding aldehyde at 4°C. When the sample contains more than 5 mg it is useful to work with greater quantities of the bisulphite. More permanganate is consumed when the lactic acid concentration is higher. The sensivity of the method permits the titration of 0.04 mg to 5 mg of lactic acid in the sample. The calculated error of the method gave 0.018 % and the normal values for blood determined in 20 human cases averaged 10.30 mg per 100 ml (Table VI). MENDEL and GOLDSCHEIDER'S method was modified in the following details: Somogyis deproteinization was performed instead metaphosphoric acid as in the original method; to avoid the evaporation of the acetic aldehyde during the heating time with sulfuric acid a special glass stopped tube is proposed (Fig. 2). The reaction with sulfuric acid and veratrol is performed in an ice bath. Blood proteins precipitants were tried and Somogyi's lattest tecnic showed better results (Table V). Colorimetric readings were done in the PULFRICH photometer using filter S 53 and a 10 mm cup. The method is accurate within an error of 0.23 % and samples of 5 to 70 microg. could be easily determined. Normal values for human blood averaged 10.78 mg per 100 ml. More accurate results were obtained with the technic of MILLER & MUNTZ. Slight modifications were introduced: deproteinization with copper sulfate and sodium tungstate; satured p-hydroxydiphenyl solution according to KOENEMANN which is stable for 5 months when stored in the ice-box. Using the PULFRICH step-photometer the error is 0.17% with samples varying from 0.1 to 10 microg. of lactic acid. The filter employed was S 57 with the 5 mm cup. The method was adapted to 0.1 ml of blood. Normal values for human blood gave an average of 10.58 mg per 100 ml.

Plancto e hidrobiologia sanitária de tanques tropicais com dáfnias e rotíferos

The engineers of the modern University City are constructing a graceful bridge, named PONTE OSWALDO CRUZ, that crosses a portion of the Guanabara Bay (Fig. 1). The work at west pillar stopped for 3 years (The concret structure in Est. 1). As it will be seen from n.º 1 — 5 of the fig. 1, Est. I, the base of the structure will have five underground boxes of reinforcement, but, to-day they are just like as five uncovered water ponds, until at present: May 1963. (Est. I — fig. 3, n.º 3 — pond n.º 3; A. — old level of the water; B.— actual level of the water; c.— green water; E.— mass of bloom of blue algae Microcystis aeruginosa). Soon after SW portion, as 5 cells in series, of the pillar abutments, and also the NE portion nearly opposite in the Tibau Mount will be filled up with earth, a new way will link Rio City and the University City. We see to day Est. I, fig. 1 — the grasses on the half arenous beach of the Tibau Point. These natural Cyperaceae and Gramineae will be desappear because of so a new road, now under construction, when completed will be 33 feet above the mean sea level, as high as the pillar, covering exactly as that place. Although rainfall was the chief source of water for these ponds, the first water (before meterorological precipitations of whatever first rain it might fall) was a common tap water mixed with Portland Cement, which exuded gradually through the pores of the concret during its hardenning process. Some data of its first cement water composition are on the chemical table, and in Tab. n.º 4 and "Resultado n.º 1". The rain — receiving surface of each pond were about 15 by 16 feet, that is, 240 square feet; when they were full of water, their depth was of 2 feet 3", having each pond about 4,000 gallons. Climatic conditions are obviously similar of those of the Rio de Janeiro City: records of temperature, of precipitation and evaporation are seen on the graphics, figs. 2, 3, 4. Our conceptions of 4 phases is merely to satisfy an easy explanation thus the first phase that of exudation of concrete. We consider the 2nd. phase formation of bacterian and cyanophycean thin pellicel. 3rd. phase - dilution by rains, and fertilisation by birds; the 4th phase - plankton flora and fauna established. The biological material arrived with the air, the rains, and also with contaminations by dusts; with big portion of sand, of earth, and leaves of trees resulted of the SW wind actions in the storming days (See - Est. I, fig. 3, G. - the mangrove trees of the Pinheiro Island). Many birds set down and rest upon the pillar structure, its faeces which are good fertilizers fall into the ponds. Some birds were commonly pigeons, black ravens, swallows, sparrows and other sea mews, moor hens, and a few sea birds of comparatively rare occurence. We get only some examples of tropical dust contaminated helioplankton, of which incipient observations were been done sparcely. See the systematic list of the species of plankters. Phytoplankters - Cyanophyta algae as a basic part for food of zooplankters, represented chiefly by rotiferse, water-fleas Moinodaphnia and other Crustacea: Ostracoda Copepoda and Insecta: Chironomidae and Culicidae larvae. The polysaprobic of septic irruptions have not been done only by heating in summer, and, a good reason of that, for example: when the fifth pond was in polysaprobic phase as the same time an alike septic phase do not happened into the 3rd. pond, therefore, both were in the same conditions of temperature, but with unlike contaminations. Among the most important aquatic organisms used as indicatiors of pollution - and microorganisms of real importance in the field of sanitary science, by authorities of renown, for instance: PALMER, PRESCOTT, INGRAM, LIEBMANN, we choose following microalgae: a) The cosmopolite algae Scenedesmus quadricuada, a common indicator in mesosaprobio waters, which lives between pH 7,0 and it is assimilative of NO[3 subscripted] and NH[4 subscripted]. b) Species of the genus Chlamydomonas; it is even possible that all the species of theses genus inhabit strong-mesosaprobic to polysaprobic waters when in massive blooms. c) Several species of Euglenaceae in fast growing number, at the same time of the protozoa Amoebidae, Vorticellidae and simultaneous with deposition of the decaying cells of the blue algae Anacystis cyanea (= Microcystis) when the consumed oxygen by organic matter resulted in 40 mg. L. But, we found, among various Euglenacea the cosmopolite species (Euglena viridis, a well known polysaprobic indicatior of which presence occur in septic zone. d) Analcystis cyanea (= M. aeruginosa) as we observed was in blooms increasing to the order of billions of cells per litter, its maximum in the summer. Temperatures 73ºF to 82ºF but even 90ºF, the pH higher than 8. When these blue algae was joined to the rotifer Brachionus calyflorus the waters gets a milky appearance, but greenished one. In fact, that cosmopolite algae is used as a mesosaprobic indicator. Into the water of the ponds its predominance finished when the septic polysaprobic conditions began. e) Ankistrodesmus falcatus was present in the 5th pond from 26the. April untill the 26th July, and when N.NH[4 subscripted] gets 1.28 mg. L. and when chlorinity stayed from 0.034 to 0.061 mg. L. It never was found at N.NH[4 subscripted] higher than 1 mg. L. The green algae A. falcatus, an indicatior of pollution, lives in moderate mesosaprobic waters. f) As everyone knows, the rotifer eggs may be widely dispersed by wind. The rotifer Asplanchna brightwelli in our observation seemed like a green colored bag, overcharged by green cells and detritus, specially into its spacious stomach, which ends blindly (the intestine, cloaca, being absent). The stock of Asplanchna in the ponds, during the construction of the bridge "PONTE OSWALDO CRUZ" inhabits alkaline waters, pH 8,0 a 8,3, and when we observed we noted its dissolved oxygen from 3.5 to 4 mg. L. In these ponds Asplanchna lived in 0,2 P.PO[4 subscripted]. (Remember the hydobiological observations foreign to braslian waters refer only from 0.06 to 0,010 mg. L. P.PO[4 subscripted]; and they refer resistance to 0.8 N.NH[4 subscripted]). By our data, that rotiger resist commonly to 1.2 until 1.8 mg. L.N.NH[4 subscripted]; here in our ponds and, when NO[2 subscripted] appears Asplanchna desappears. It may be that Asplanchna were devoured by nitrite resistant animals of by Culicidae or other mosquitoes devoured by Due to these facts the number and the distribution of Asplanchna varies considerabley; see - plates of plankton successions. g) Brachionus one of the commonest members of class Rotatoria was frquently found in abundance into the ponds, and we notice an important biological change produce by the rotifer Brachonus colyciflorus: the occurence of its Brachionus clayciflorus forms pallas, is rare in Brazil, as we know about this. h) When we found the water flea MOinodaphnia we do not record simultanous presence of the blue algae Agmenellun (= Merismopedia).

Oxygen isotope thermometry in carbonatites, Fuerteventura, Canary Islands, Spain

Crystallization temperatures of the oceanic carbonatites of Fuerteventura, Canary Islands, have been determined from oxygen isotope fractionations between calcite, silicate minerals (feldspar, pyroxene, biotite, and zircon) and magnetite. The measured fractionations have been interpreted in the light of late stage interactions with meteoric and/or magmatic water. Cathodoluminescence characteristics were investigated for the carbonatite minerals in order to determine the extent of alteration and to select unaltered samples. Oxygen isotope fractionations of minerals of unaltered samples yield crystallization temperatures between 450 and 960degreesC (average 710degreesC). The highest temperature is obtained from pyroxene-calcite pairs. The above range is in agreement with other carbonatite thermometric Studies. This is the first study that provides oxygen isotope data coupled with a CL study on carbonatite-related zircon. The CL pictures revealed that the zircon is broken and altered in the carbonatites and in associated syenites. Regarding geological field evidences of syenite-carbonatite relationship and the close agreement of published zircon U/Pb and whole rock and biotite K/Ar and Ar-Ar age data, the most probable process is early zircon crystallization from the syenite magma and late-stage reworking during magma evolution and carbonatite segregation. The oxygen isotope fractionations between zircon and other carbonatite minerals (calcite and pyroxene) support the assumption that the zircon would correspond to the early crystallization of syenite-carbonatite magmas.

Mechanisms of inflammation in gout.

An acute attack of gout is a paradigm of acute sterile inflammation, as opposed to pyogenic inflammation. Recent studies suggest that the triggering of IL-1beta release from leucocytes lies at the heart of a cascade of processes that involves multiple cytokines and mediators. The NLRP3 inflammasome appears to have a specific role in this regard, but the biochemical events leading to its activation are still not well understood. We review the known mechanisms that underlie the inflammatory process triggered by urate crystals and suggest areas that require further research.

Stable hydrogen and oxygen isotope composition of waters from mine tailings in different climatic environments

The stable isotope composition of waters (delta H-2, delta O-18) can be used as a natural tracer of hydrologic processes in systems affected by acid mine drainage. We investigated the delta H-2 and delta O-18 values of pore waters from four oxidizing sulfidic mine tailings impoundments in different climatic regions of Chile (Piuquenes at La Andina with Alpine climate, Cauquenes and Caren at El Teniente with Mediterranean climate, and Talabre at the Chuquicamata deposit with hyperarid climate). No clear relationship was found between altitude and isotopic composition. The observed displacement of the tailings pore waters from the local meteoric water line toward higher delta O-18 values (by similar to +2% delta O-18 relative to delta H-2) is partly due to water-rock interaction processes, including hydration and O-isotope exchange with sulfates and Fe(III) oxyhydroxides produced by pyrite oxidation. In most tailings, from the saturated zone toward the surface, isotopically different zones can be distinguished. Zone I is characterized by an upward depletion of H-2 and O-18 in the pore waters from the saturated zone and the lowermost vadose zone, due to ascending diffused isotopically light water triggered by the constant loss of water vapor by evaporation at the surface. In zone II, the capillary flow of a mix of vapor and liquid water causes an evaporative isotopic enrichment in H-2 and O-18. At the top of the tailings in dry climate a zone III between the capillary zone and the surface contains isotopically light diffused and atmospheric water vapor. In temperate climates, the upper part of the profile is affected by recent rainfall and zone III may not differ isotopically from zone II.

Contact metamorphism and emplacement of the western Adamello tonalite

The geodynamic forces acting in the Earth's interior manifest themselves in a variety of ways. Volcanoes are amongst the most impressive examples in this respect, but like with an iceberg, they only represent the tip of a more extensive system hidden underground. This system consists of a source region where melt forms and accumulates, feeder connections in which magma is transported towards the surface, and different reservoirs where it is stored before it eventually erupts to form a volcano. A magma represents a mixture of melt and crystals. The latter can be extracted from the source region, or form anywhere along the path towards their final crystallization place. They will retain information of the overall plumbing system. The host rocks of an intrusion, in contrast, provide information at the emplacement level. They record the effects of thermal and mechanical forces imposed by the magma. For a better understanding of the system, both parts - magmatic and metamorphic petrology - have to be integrated. I will demonstrate in my thesis that information from both is complementary. It is an iterative process, using constraints from one field to better constrain the other. Reading the history of the host rocks is not always straightforward. This is shown in chapter two, where a model for the formation of clustered garnets observed in the contact aureole is proposed. Fragments of garnets, older than the intrusive rocks are overgrown by garnet crystallizing due to the reheating during emplacement of the adjacent pluton. The formation of the clusters is therefore not a single event as generally assumed but the result of a two-stage process, namely the alteration of the old grains and the overgrowth and amalgamation of new garnet rims. This makes an important difference when applying petrological methods such as thermobarometry, geochronology or grain size distributions. The thermal conditions in the aureole are a strong function of the emplacement style of the pluton. therefore it is necessary to understand the pluton before drawing conclusions about its aureole. A study investigating the intrusive rocks by means of field, geochemical, geochronologi- cal and structural methods is presented in chapter three. This provided important information about the assembly of the intrusion, but also new insights on the nature of large, homogeneous plutons and the structure of the plumbing system in general. The incremental nature of the emplacement of the Western Adamello tonalité is documented, and the existence of an intermediate reservoir beneath homogeneous plutons is proposed. In chapter four it is demonstrated that information extracted from the host rock provides further constraints on the emplacement process of the intrusion. The temperatures obtain by combining field observations with phase petrology modeling are used together with thermal models to constrain the magmatic activity in the immediate intrusion. Instead of using the thermal models to control the petrology result, the inverse is done. The model parameters were changed until a match with the aureole temperatures was obtained. It is shown, that only a few combinations give a positive match and that temperature estimates from the aureole can constrain the frequency of ancient magmatic systems. In the fifth chapter, the Anisotropy of Magnetic Susceptibility of intrusive rocks is compared to 3D tomography. The obtained signal is a function of the shape and distribution of ferromagnetic grains, and is often used to infer flow directions of magma. It turns out that the signal is dominated by the shape of the magnetic crystals, and where they form tight clusters, also by their distribution. This is in good agreement with the predictions made in the theoretical and experimental literature. In the sixth chapter arguments for partial melting of host rock carbonates are presented. While at first very surprising, this is to be expected when considering the prior results from the intrusive study and experiments from the literature. Partial melting is documented by compelling microstructures, geochemical and structural data. The necessary conditions are far from extreme and this process might be more frequent than previously thought. The carbonate melt is highly mobile and can move along grain boundaries, infiltrating other rocks and ultimately alter the existing mineral assemblage. Finally, a mineralogical curiosity is presented in chapter seven. The mineral assemblage magne§site and calcite is in apparent equilibrium. It is well known that these two carbonates are not stable together in the system Ca0-Mg0-Fe0-C02. Indeed, magnesite and calcite should react to dolomite during metamorphism. The presented explanation for this '"forbidden" assemblage is, that a calcite melt infiltrated the magnesite bearing rock along grain boundaries and caused the peculiar microstructure. This is supported by isotopie disequilibrium between calcite and magnesite. A further implication of partially molten carbonates is, that the host rock drastically looses its strength so that its physical properties may be comparable to the ones of the intrusive rocks. This contrasting behavior of the host rock may ease the emplacement of the intrusion. We see that the circle closes and the iterative process of better constraining the emplacement could start again. - La Terre est en perpétuel mouvement et les forces tectoniques associées à ces mouvements se manifestent sous différentes formes. Les volcans en sont l'un des exemples les plus impressionnants, mais comme les icebergs, les laves émises en surfaces ne représentent que la pointe d'un vaste système caché dans les profondeurs. Ce système est constitué d'une région source, région où la roche source fond et produit le magma ; ce magma peut s'accumuler dans cette région source ou être transporté à travers différents conduits dans des réservoirs où le magma est stocké. Ce magma peut cristalliser in situ et produire des roches plutoniques ou alors être émis en surface. Un magma représente un mélange entre un liquide et des cristaux. Ces cristaux peuvent être extraits de la source ou se former tout au long du chemin jusqu'à l'endroit final de cristallisation. L'étude de ces cristaux peut ainsi donner des informations sur l'ensemble du système magmatique. Au contraire, les roches encaissantes fournissent des informations sur le niveau d'emplacement de l'intrusion. En effet ces roches enregistrent les effets thermiques et mécaniques imposés par le magma. Pour une meilleure compréhension du système, les deux parties, magmatique et métamorphique, doivent être intégrées. Cette thèse a pour but de montrer que les informations issues de l'étude des roches magmatiques et des roches encaissantes sont complémentaires. C'est un processus itératif qui utilise les contraintes d'un domaine pour améliorer la compréhension de l'autre. Comprendre l'histoire des roches encaissantes n'est pas toujours aisé. Ceci est démontré dans le chapitre deux, où un modèle de formation des grenats observés sous forme d'agrégats dans l'auréole de contact est proposé. Des fragments de grenats plus vieux que les roches intru- sives montrent une zone de surcroissance générée par l'apport thermique produit par la mise en place du pluton adjacent. La formation des agrégats de grenats n'est donc pas le résultat d'un seul événement, comme on le décrit habituellement, mais d'un processus en deux phases, soit l'altération de vieux grains engendrant une fracturation de ces grenats, puis la formation de zone de surcroissance autour de ces différents fragments expliquant la texture en agrégats observée. Cette interprétation en deux phases est importante, car elle engendre des différences notables lorsque l'on applique des méthodes pétrologiques comme la thermobarométrie, la géochronologie ou encore lorsque l'on étudie la distribution relative de la taille des grains. Les conditions thermales dans l'auréole de contact dépendent fortement du mode d'emplacement de l'intrusion et c'est pourquoi il est nécessaire de d'abord comprendre le pluton avant de faire des conclusions sur son auréole de contact. Une étude de terrain des roches intrusives ainsi qu'une étude géochimique, géochronologique et structurale est présente dans le troisième chapitre. Cette étude apporte des informations importantes sur la formation de l'intrusion mais également de nouvelles connaissances sur la nature de grands plutons homogènes et la structure de système magmatique en général. L'emplacement incrémental est mis en évidence et l'existence d'un réservoir intermédiaire en-dessous des plutons homogènes est proposé. Le quatrième chapitre de cette thèse illustre comment utiliser l'information extraite des roches encaissantes pour expliquer la mise en place de l'intrusion. Les températures obtenues par la combinaison des observations de terrain et l'assemblage métamorphique sont utilisées avec des modèles thermiques pour contraindre l'activité magmatique au contact directe de cette auréole. Au lieu d'utiliser le modèle thermique pour vérifier le résultat pétrologique, une approche inverse a été choisie. Les paramètres du modèle ont été changés jusqu'à ce qu'on obtienne une correspondance avec les températures observées dans l'auréole de contact. Ceci montre qu'il y a peu de combinaison qui peuvent expliquer les températures et qu'on peut contraindre la fréquence de l'activité magmatique d'un ancien système magmatique de cette manière. Dans le cinquième chapitre, les processus contrôlant l'anisotropie de la susceptibilité magnétique des roches intrusives sont expliqués à l'aide d'images de la distribution des minéraux dans les roches obtenues par tomographie 3D. Le signal associé à l'anisotropie de la susceptibilité magnétique est une fonction de la forme et de la distribution des grains ferromagnétiques. Ce signal est fréquemment utilisé pour déterminer la direction de mouvement d'un magma. En accord avec d'autres études de la littérature, les résultats montrent que le signal est dominé par la forme des cristaux magnétiques, ainsi que par la distribution des agglomérats de ces minéraux dans la roche. Dans le sixième chapitre, une étude associée à la fusion partielle de carbonates dans les roches encaissantes est présentée. Si la présence de liquides carbonatés dans les auréoles de contact a été proposée sur la base d'expériences de laboratoire, notre étude démontre clairement leur existence dans la nature. La fusion partielle est documentée par des microstructures caractéristiques pour la présence de liquides ainsi que par des données géochimiques et structurales. Les conditions nécessaires sont loin d'être extrêmes et ce processus pourrait être plus fréquent qu'attendu. Les liquides carbonatés sont très mobiles et peuvent circuler le long des limites de grain avant d'infiltrer d'autres roches en produisant une modification de leurs assemblages minéralogiques. Finalement, une curiosité minéralogique est présentée dans le chapitre sept. L'assemblage de minéraux de magnésite et de calcite en équilibre apparent est observé. Il est bien connu que ces deux carbonates ne sont pas stables ensemble dans le système CaO-MgO-FeO-CO.,. En effet, la magnésite et la calcite devraient réagir et produire de la dolomite pendant le métamorphisme. L'explication présentée pour cet assemblage à priori « interdit » est que un liquide carbonaté provenant des roches adjacentes infiltre cette roche et est responsable pour cette microstructure. Une autre implication associée à la présence de carbonates fondus est que la roche encaissante montre une diminution drastique de sa résistance et que les propriétés physiques de cette roche deviennent comparables à celles de la roche intrusive. Cette modification des propriétés rhéologiques des roches encaissantes peut faciliter la mise en place des roches intrusives. Ces différentes études démontrent bien le processus itératif utilisé et l'intérêt d'étudier aussi bien les roches intrusives que les roches encaissantes pour la compréhension des mécanismes de mise en place des magmas au sein de la croûte terrestre.

Histogical and ultrastructural aspects of the brindley's glands of pantrongylus megistus (Burmeister, 1835) (Hemiptera: Reduviidae)

The Brindley's glands of Panstrongylus megistus were studied under the antomic, histologic and ultrastructural point of view. These glands located in the insect's methatorax are paired and have an opening near the third parir of the feet. Beside this aperture, ther are evaporation areas. Shape, sixe and aspect of the gland vary according to the feeding status. The glands are composed by a tubular part corresponding to the duct and a sack-like portion corrsponding to the secretory part. By electron microscopy we observed that the basal part of the epithelium has many interdigitations associated with mitochondria. On the apical surface where epicuticular foldings are located an electonlucent space is often seen. The glands are composed of the following elements: 1) superficial epithelial cells, located just below the apical surface foldings; 2) secretory cells; which are long and have an intracellular canalicule which changes according to the functional state of the cell; 3) a collecting duct to the secretory cells and covered with an epicuticle, reaching up to the gland's lumen; and 4) cells around the duct.