Littérature scientifique sur le sujet « Porous magma »
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Articles de revues sur le sujet "Porous magma"
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Scott, David R., et David J. Stevenson. « Magma ascent by porous flow ». Journal of Geophysical Research 91, B9 (1986) : 9283. http://dx.doi.org/10.1029/jb091ib09p09283.
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Olsen, Sakiko N., Bruce D. Marsh et Lukas P. Baumgartner. « Modelling mid-crustal migmatite terrains as feeder zones for granite plutons : the competing dynamics of melt transfer by bulk versus porous flow ». Earth and Environmental Science Transactions of the Royal Society of Edinburgh 95, no 1-2 (mars 2004) : 49–58. http://dx.doi.org/10.1017/s0263593300000912.
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ABSTRACTThe common association of mid-crustal migmatites with an upper-level granite pluton could indicate that the migmatites are a feeder zone for the pluton. If magma from a deeper level pervasively intrudes a high temperature metamorphic complex, most of the intruded magma would not freeze because of the prevailing temperature. The interaction between the magma and country rocks, which could include partial melting and crystallisation of the magma passing through, would modify magma to a more granitic composition, as found in the higher-level pluton.The physical aspect of the magma transport through such a hot feeder zone is modelled by introducing a dimensionless melt transport (MT) number, which is the ratio of the rate of melt movement caused by the bulk flow of the entire mass (melt+solid) to that of porous media flow of melt only through the solid framework. The MT number is strongly dependent on the melt content of the melt-rich zone (MRZ), the diameter of the MRZ and typical particle size in the MRZ.The ∼300-Ma, diatexitic, Lauterbrunnen migmatites (LM) in the Aar massif, Swiss Alps, may be such a feeder zone for the nearby 303-Ma Gastern granite (GG). The chemical and field evidence indicates that the LM formed by an intrusion of intermediate composition magma, which interacted with country rocks to produce a magma of GG composi
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Melnik, O. E., A. A. Afanasyev et G. A. Zarin. « Magma degassing during eruption through water-saturated porous rocks ». Doklady Physics 61, no 5 (mai 2016) : 235–38. http://dx.doi.org/10.1134/s1028335816050074.
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Rees Jones, David W., et Richard F. Katz. « Reaction-infiltration instability in a compacting porous medium ». Journal of Fluid Mechanics 852 (2 août 2018) : 5–36. http://dx.doi.org/10.1017/jfm.2018.524.
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Certain geological features have been interpreted as evidence of channelized magma flow in the mantle, which is a compacting porous medium. Aharonov et al. (J. Geophys. Res., vol. 100 (B10), 1995, pp. 20433–20450) developed a simple model of reactive porous flow and numerically analysed its instability to channels. The instability relies on magma advection against a chemical solubility gradient and the porosity-dependent permeability of the porous host rock. We extend the previous analysis by systematically mapping out the parameter space. Crucially, we augment numerical solutions with asymptotic analysis to better understand the physical controls on the instability. We derive scalings for the critical conditions of the instability and analyse the associated bifurcation structure. We also determine scalings for the wavelengths and growth rates of the channel structures that emerge. We obtain quantitative theories for and a physical understanding of, first, how advection or diffusion over the reactive time scale sets the horizontal length scale of channels and, second, the role of viscous compaction of the host rock, which also affects the vertical extent of channelized flow. These scalings allow us to derive estimates of the dimensions of emergent channels that are consistent with the geologic record.
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Claydon, R. V., et B. R. Bell. « The structure and petrology of ultrabasic rocks in the southern part of the Cuillin Igneous Complex, Isle of Skye ». Transactions of the Royal Society of Edinburgh : Earth Sciences 83, no 4 (1992) : 635–53. http://dx.doi.org/10.1017/s0263593300003345.
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AbstractThe ultrabasic rocks of the southern portion of the Early Tertiary Cuillin Igneous Complex, Isle of Skye, are recognised as forming a Peridotite Series s.l. and have been separated into six distinct structural–lithological units. These units range from almost pure dunite (Unit 1, at the lowest structural level), through to feldspathic peridotites and allivalites (Units 5 and 6, at the highest structural levels). Detailed field and mineralogical studies indicate that both cumulus and postcumulus processes involving ultrabasic (picritic) magmas may be identified, and that the latter processes have significantly modified many of the primary features of these rocks.Layering, both modal and phase, is present within all six units, although it is more prominent within the higher units, especially Units 5 and 6. Differing orientations of fabrics defined by cumulus spinel and intercumulus plagioclase layers within Unit 3 indicate the important role of compaction and intercumulus melt migration. Unit 4 is extremely heterogeneous, involving material ranging in composition from peridotite to allivalite, and provides clear evidence for postcumulus melt movement, magma-mixing, disruption and brecciation. Units 5 and 6 developed with a more porous cumulus framework, giving rise to dendritic growths involving cumulus olivine and poikilitic plagioclase.It is concluded that postcumulus melt movement, injection and magma-mixing, involving ultrabasic magmas, were significant processes in the formation of the ultrabasic rocks of the Cuillin Igneous Complex.
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KOYAGUCHI, TAKEHIRO. « MULTIPHASE FLOWS IN MAGMATISM ». International Journal of Modern Physics B 07, no 09n10 (20 avril 1993) : 1997–2023. http://dx.doi.org/10.1142/s0217979293002730.
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Diversity of volcanic activities reflects various styles of magma flows. One of the most important characters of the magma flows is that they are composed of gas, liquid and solid phases (multiphase flow). Macroscopic behaviours of multiphase flows are affected by their internal microstructures including the distribution of each phase and the shape of the boundaries between the two phases. Magma segregation from partially molten rock occurs by porous flow being accompanied with compaction of the matrix rock, the macroscopic behaviours of which are governed by microscopic flows of the melt at grain boundaries and deformation of each crystal. The fluctuation of magma effusion at volcanic eruptions is explained by instability of gas-liquid two-phase flow, which depends on motion of each bubble and the ability of bubbles to coalesce. Complex features of pyroclastic flow result from a wide range of grain-size, and hence, variable settling velocities of volcanic fragments within the flow. Physical processes of these multiphase flows in magmatism are reviewed.
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Alidibirov, Mikhail, et Vsevolod Panov. « Magma fragmentation dynamics : experiments with analogue porous low-strength material ». Bulletin of Volcanology 59, no 7 (23 juin 1998) : 481–89. http://dx.doi.org/10.1007/s004450050205.
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Ichihara, Mie, Daniel Rittel et Bradford Sturtevant. « Fragmentation of a porous viscoelastic material : Implications to magma fragmentation ». Journal of Geophysical Research : Solid Earth 107, B10 (octobre 2002) : ECV 8–1—ECV 8–14. http://dx.doi.org/10.1029/2001jb000591.
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Correale, Alessandra, Vittorio Scribano et Antonio Paonita. « A Volcanological Paradox in a Thin-Section : Large Explosive Eruptions of High-Mg Magmas Explained Through a Vein of Silicate Glass in a Serpentinized Peridotite Xenolith (Hyblean Area, Sicily) ». Geosciences 9, no 4 (29 mars 2019) : 150. http://dx.doi.org/10.3390/geosciences9040150.
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Ultramafic magmas (MgO ≥ 18 wt%) are generally thought to be primary mantle melts formed at temperatures in excess of 1600 °C. Volatile contents are expected to be low, and accordingly, high-Mg magmas generally do not yield large explosive eruptions. However, there are important exceptions to low explosivity that require an explanation. Here we show that hydrous (hence, potentially explosive) ultramafic magmas can also form at crustal depths at temperatures even lower than 1000 °C. Such a conclusion arose from the study of a silicate glass vein, ~1 mm in thickness, cross-cutting a mantle-derived harzburgite xenolith from the Valle Guffari nephelinite diatreme (Hyblean area, Sicily). The glass vein postdates a number of serpentine veins already existing in the host harzburgite, thus reasonably excluding that the melt infiltrated in the rock at mantle depths. The glass is highly porous at the sub-micron scale, it also bears vesicles filled by secondary minerals. The distribution of some major elements corresponds to a meimechite composition (MgO = 20.35 wt%; Na2O + K2O < 1 wt%; and TiO2 > 1 wt%). On the other hand, trace element distribution in the vein glass nearly matches the nephelinite juvenile clasts in the xenolith-bearing tuff-breccia. These data strongly support the hypothesis that an upwelling nephelinite melt (MgO = 7–9 wt%; 1100 ≤ T ≤ 1250 °C) intersected fractured serpentinites (T ≤ 500 °C) buried in the aged oceanic crust. The consequent dehydroxilization of the serpentine minerals gave rise to a supercritical aqueous fluid, bearing finely dispersed, hydrated cationic complexes such as [Mg2+(H2O)n]. The high-Mg, hydrothermal solution "flushed" into the nephelinite magma producing an ultramafic, hydrous (hence, potentially explosive), hybrid magma. This hypothesis explains the volcanological paradox of large explosive eruptions produced by ultramafic magmas.
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Woods, Andrew W., et Michael J. Stock. « Some fluid mechanical constraints on crystallization and recharge within sills ». Philosophical Transactions of the Royal Society A : Mathematical, Physical and Engineering Sciences 377, no 2139 (7 janvier 2019) : 20180007. http://dx.doi.org/10.1098/rsta.2018.0007.
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The injection of hot magma into a sill can lead to heating and melting of the walls and roof of the reservoir while the injected magma cools and crystallizes. If the crystals are relatively dense, they will try to sediment from the injected magma to form a cumulate layer. In this cumulate layer, the crystals form a porous framework which traps the melt as it is built up. As the melt within the sill continually cools and precipitates dense crystals, there will be a gradual reduction in the density of the remaining silicate liquid. As a result, the melt which is progressively trapped in the pore space of the cumulate layer will become stably stratified in density. Using an idealized model of the fluid mechanical and thermodynamical principles, we explore some of the controls on the thickness and density stratification of cumulate layers following replenishment of a sill-like magma chamber. We show the balance between jamming of the crystal laden melt to form a homogeneous layer and the formation of a stratified cumulate zone depends on the cooling time scale compared to the sedimentation time scale. A key finding is that the composition and stratification in a packed crystal–melt suspension and the associated cumulate layer formed by cooling an intrusion of hot melt injected into the crust may have considerable variability, depending on the properties of the overlying roof melt and the size and hence fall speed of crystals which form in the melt. This article is part of the Theo Murphy meeting issue ‘Magma reservoir architecture and dynamics’.
Thèses sur le sujet "Porous magma"
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Bergantz, George W. « Double-diffusive boundary layer convection in a porous medium : implications for fractionation in magma chambers ». Thesis, Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/26030.
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Küppers, Ulrich. « Nature and efficiency of pyroclast generation from porous magma insights from field investigations and laboratory experiments / ». [S.l.] : [s.n.], 2005. http://edoc.ub.uni-muenchen.de/archive/00004587.
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Küppers, Ulrich. « Nature and efficiency of pyroclast generation from porous magma : Insights from field investigations and laboratory experiments ». Diss., lmu, 2005. http://nbn-resolving.de/urn:nbn:de:bvb:19-45876.
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Gressier, Jean-Baptiste. « Sills en milieu poreux : rôle des pressions de fluides, de la rhéologie et des échanges chimiques magma-sédiments ». Le Mans, 2010. http://cyberdoc.univ-lemans.fr/theses/2010/2010LEMA1033.pdf.
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Dans la croûte supérieure, fragile, le fort contraste de rhéologie (viscosité) entre le magma et l’encaissant favorise la mise en place d’intrusions magmatiques planaires par fracturation hydraulique. Ce mode de mise en place des magmas conduit à la formation de deux types d’intrusions planaires: les dykes, subverticaux, et les sills, subhorizontaux. Nous nous sommes intéressés à deux problématiques liées à l’injection de sills en milieu poreux : (1) la profondeur de la transition dyke-sill, et (2) les conséquences mécaniques et chimiques de l’injection d’un sill dans un sédiment plastique. Dans le premier cas, nous nous sommes focalisés sur le rôle joué par les fluides sous pression présents dans la porosité de nombreuses formations sédimentaires. Grace à un nouveau protocole de modélisation analogique, nous avons montré que l’effet des pressions de fluide sur les contraintes dépend de la distribution des surpressions, et que les surpressions de fluide aux pores sont un des paramètres contrôlant la transition dyke-sill. Dans le deuxième cas, pour quantifier les échanges chimiques entre sill et encaissant, nous avons étudié les évolutions chimiques du magma et des sédiments de part et d’autre des épontes d’un sill. Nous avons ainsi mis en évidence un dégazage limité de CO2 et un enrichissement (relatif) en Terres Rares des zones altérées par la circulation de fluides. Enfin, à l’aide d’une modélisation numérique, nous avons contraint l’importance de la part plastique dans la déformation d’un encaissant sédimentaire, lors de la mise en place d’un sill. Nous avons montré une déformation plastique très localisée qui se révèle plus importante dans le cas de sills segmentésIn the upper crust, the high contrast of rheology (viscosity) between magma and host rocks favors the development of planar magmatic intrusions by hydraulic fracturing. This mode of magma setup led to the formation of two types of planar intrusions: dykes, subvertical, and sills, subhorizontal. We focused on two issues related to the injection of sills in porous media: (1) the depth of the dyke-sill transition, and (2) Mechanical and chemical consequences of the injection of a sill in a plastic sediment. In the first case, we focused on the role of fluid pressure present in the porosity of many sedimentary formations. Thanks to a new protocol for analog modeling, we have shown that the effect of fluid pressures on the constraints depends on the distribution of overpressure, and overpressure of the pore fluid is a parameter controlling the dyke-sill transition. In the second case, to quantify the chemical exchanges between sill and host rocks, we studied the chemical evolution of magma and sediment from both sides of the walls of a sill. We have identified a limited outgassing of CO2 and an enrichment (relative) in rare earth elements, in areas affected by the circulation of fluids. Finally, using numerical modeling, we have shown the importance of plasticity in deformation of a sedimentary host rock at the emplacement of a sill. We showed a highly localized plastic deformation which is more important in the case of segmented sills
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Boulanger, Marine. « Le devenir des liquides au sein de la croûte océanique des dorsales à expansion lente : nouveaux apports de l'étude d'Atlantis Bank (dorsale Sud-Ouest Indienne) ». Electronic Thesis or Diss., Université de Lorraine, 2020. http://www.theses.fr/2020LORR0030.
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Les processus magmatiques qui régissent l'accrétion crustale au niveau des dorsales médio-océaniques à expansion lente restent à l'heure actuelle mal contraints. Parmi les processus potentiellement impliqués dans l'évolution des réservoirs de magma de la croûte inférieure, les réactions associées à des écoulements poreux réactifs au travers de bouillies cristallines - ou mush - tendent à supplanter les processus classiques de cristallisation simple des magmas. La part de ces processus dans la formation des gabbros cumulatifs de base de croûte est dépendante des modes de migration des liquides, qui sont eux-mêmes corrélés à la géométrie des réservoirs considérés. En combinant des études structurales, pétrographiques et géochimiques à haute résolution de sections in situ forées dans un corps complexe océanique de la dorsale Sud-Ouest indienne, j'ai pu apporter de nouvelles contraintes sur les modes de formation et d'évolution des réservoirs magmatiques impliqués lors de l'accrétion crustale. Le modèle de réservoir développé est généralisable, au moins en partie, à d'autres portions de croûte inférieure océanique. Ce modèle, ainsi que les nouvelles contraintes de l'étude expérimentale couplée des processus de cristallisation, ouvre la voie vers de nouvelles quantifications des processus d'interaction liquides-roches dans la différenciation des lithologies gabbroïques, et de manière plus générale dans l'évolution des liquides magmatiques de la croûte océanique. Ces développements vont de pair avec l'évolution au cours des dernières décennies de la vision des systèmes magmatiques crustaux, passant de chambres magmatiques constituées de liquides vers des modèles de réservoirs magmatiques majoritairement constitués de mush cristallinsMagmatic processes that govern crustal accretion at mid-ocean ridges still need to be better constrained. Among the processes potentially involved in the evolution of the lower crust magma reservoirs, reactions associated with reactive porous flow through crystal mushes tend to be considered as one of the predominant processes together with simple crystallization of magmas. The share of these processes during magma differentiation is dependent on the modes of melt migration and is thus correlated to the geometry of the reservoirs considered. By combining high-resolution structural, petrographic and geochemical studies of in situ sections drilled in an oceanic core complex of the Southwest Indian Ridge, I was able to bring new constraints on the formation and evolution of magmatic reservoirs involved in crustal accretion. All or part of the igneous reservoir model developed herein can be applied to other sections of lower oceanic crust. This model, together with additional constraints obtained by the coupled experimental petrology study of crystallization processes, paves the way for new quantifications of the involvement of melt-rock reactions in the differentiation of gabbroic lithologies, and more generally in the evolution of melts within the oceanic crust. Those developments are consistent with the constant evolution in recent decades of the understanding of crustal magmatic systems, which shifted from melt-filled magma chambers to igneous reservoir models mostly composed of crystal mushes
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Abramo, Maria Cristina Cavallari. « Estruturas portuárias nas apoikias da Magna Grécia e Sicília entre os séculos VIII a V a.C. : relação entre porto e malha urbana ». Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/71/71131/tde-27062013-142248/.
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Partindo de considerações acerca da importância do mar, do comércio e das trocas com estrangeiros para o modo de vida grego, esta pesquisa tem o objetivo de entender qual era o local ocupado pelos portos e pelas cidades portuárias nessa configuração. Através da localização do porto em sete cidades fundadas durante os movimentos de expansão grega para o ocidente buscamos situar o porto em relação às estruturas urbanas importantes tais como acrópole, ágora, templos e muralhas. Ao estabelecer essas relações queremos entender não só o lugar físico ocupado pelo porto mas também e principalmente, o que a sua localização física pode representar e nos dizer acerca de sua posição na hierarquia social de cada cidade.Considering the importance of the sea, commerce and trading with foreign people for the Greek life style, this research tries to understand the place of harbours and harbour cities in this scenario. Based on the location of the port in seven cities established during the Greek expansionist movements to the west, our aim is to establish the place of the port towards the important urban structures such as the acropolis, agora, sanctuaries and walls. By establishing these relations we try to understand not only the physical location of the port but what this location could represent and tell us about the situation of the port within the social hierarchy of each city.
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Kueppers, U. « Nature and efficiency of pyroclast generation from porous magma : Insights from field investigations and laboratory experiments ». Thesis, 2005. http://hdl.handle.net/2122/1169.
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Enhanced knowledge of pre- and syn-eruptive processes is vital to deal with the increasing threat imposed to population and infrastructure by volcanoes that have been active historically and may potentially erupt in future. For many years, most of this knowledge was received from experiments on analogue materials and/or numerical models. In order to increase their significance and applicability for the “real” case, the natural complexity may not be oversimplified and the input parameters must be reliable and realistic. In the light of this, a close connection of field and laboratory work is essential. Volcanic eruptions may be phreatic, phreatomagmatic or magmatic, the latter scenario of which was addressed in this study. Rising magma is subject to decreasing lithostatic pressure. As a direct consequence, volatiles become increasingly oversaturated and bubbles will nucleate and grow depending on initial volatile content and melt viscosity. Both factors directly influence the diffusivity that limits the rate of bubble growth. Increasing amounts of bubbles increase the buoyancy difference to the surrounding rocks and lead to an acceleration of the rising melt-bubble mixture. Beside these limiting factors, the overpressure in the gas bubbles greatly depends on the magma’s ascent speed as it controls the residence time to conditions favourable to degassing (a combination of lithostatic pressure and magma temperature) and the time of overpressure reduction due to degassing. Volcanic eruptions occur when the bubbly melt can no longer withstand the exerted stress that derives from the overlying weight (lithostatic pressure), the expanding gas bubbles (internal gas overpressure) and different ascent velocities in the conduit (velocity profile). The melt will be fragmented and the gas-pyroclast mixture will be erupted. This study has combined close investigation of the deposits of the 1990-1995 eruption of Unzen volcano, Japan and detailed laboratory investigations on samples of this eruption and other volcanoes. The field work intended to reveal the density distribution of samples from within the eruptive products. Although all samples already underwent one eruption, their physical state (e.g. crystallinity, porosity) mostly remained close to sub-surface pre-eruption conditions due to their high viscosity and accordingly allowed their usage for the analysis of the fragmentation behaviour. In that purpose, rapid decompression experiments that simulate volcanic eruptions triggered by internal gas overpressure have been performed at 850 °C to evaluate fragmentation threshold and fragmentation efficiency. Laboratory investigations of that kind are one approach to bridge the gap between observational field volcanology and risk assessment as they reveal information on what can not be investigated closely but what is essential to know for realistic eruption models and the adjacent hazard mitigation. Changing the experimental conditions and close investigation of the artificial products reveals the influence of physical properties on the fragmentation behaviour. The density distribution inside a dome and the upper part of the conduit is crucial to the eruptive style of an explosive volcano. This information cannot be collected during an ongoing eruption but is important for future hazard assessment via modelling conduit flow and dome collapse/explosion behaviour. Therefore, the percentage of the mass fractions of all rock types in the primary and secondary volcanic deposits must be evaluated. For this purpose and at the lowest logistic effort, field-based density measurements have been performed on Unzen volcano, Japan. The resultant density distribution was found to be generally bimodal at constant peak values but changing peak ratios. The most abundant rock types at Unzen exhibited an open porosity of 8 and 20 vol.%, respectively. The porosity was found to be arranged in layers of cm- to dm-scale that were oriented subparallel to flow direction, i.e. subvertical within the conduit and flank-parallel within the dome lobes. The achieved results allowed for an internal picture of the dome during the last eruption of Unzen volcano. The evaluated picture of the density distribution within the uppermost parts of the conduit and the dome itself allowed for insights into and a better understanding of magma ascent and degassing conditions at Unzen volcano during its last eruption. Knowledge of the density distribution is additionally required to draw conclusions from the results of laboratory investigations on the fragmentation behaviour to the monitored behaviour of Unzen volcano during its last eruption. In the laboratory, the fragmentation behaviour upon rapid decompression has been investigated in a modified fragmentation bomb (Spieler et al., 2004). At 850 °C, initial overpressure conditions as high as 50 MPa have been applied to sample cylinders (25 mm diameter, 60 mm length) drilled from natural samples. In a first step, the minimum overpressure required to cause complete sample fragmentation (= fragmentation threshold, ΔPfr) has been evaluated. Results from samples of several volcanoes (Unzen, Montserrat, Stromboli, and Mt. St. Helens) showed that ΔPfr mainly depended on open porosity and permeability of the specific sample as these parameters were controlling pressure build-up and loss. The experiments further revealed that sample fragmentation was not the result of a single process but the result of a combination of simultaneously occurring processes as indicated by Alidibirov et al. (2000). The degree of influence of a single process to the fragmentation behaviour was found to be porosity-dependent. Further experiments at initial pressure conditions above ΔPfr and close investigation of the artificially generated pyroclasts allowed evaluating the fragmentation efficiency upon changing physical properties of the used samples. The efficiency of sample size reduction was investigated by grain-size analysis (dry sieving for particles bigger than 0.25 mm and wet laser refraction for particles smaller than 0.25 mm) and surface area measurements (by Argon adsorption). Results of experiments with samples of different porosities at different initial pressure values showed that the efficiency of fragmentation increased with increasing energy. The energy available for fragmentation was estimated from the open porosity and the applied pressure. A series of abrasion experiments was performed to shed light on the grain size reduction due to particle-particle interaction during mass movements. The degree of abrasion was found to be primarily depending on porosity and experimental duration. The results showed that abrasion may change the density distribution of block-and-ash flows (BAF) by preferentially abrading porous clasts. However, during the short drying interval prior to the analysis of the experimental pyroclasts, abrasion-induced grain-size reduction only played a minor role and was assumed to be negligible.Earth & Environmental Sciences, University of Munich (LMU)
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Scott, David Russell. « Magmons : Solitary Waves Arising in the Buoyant Ascent of Magma by Porous Flow through a Viscously Deformable Matrix ». Thesis, 1987. https://thesis.library.caltech.edu/11448/2/Scott_DR_1987.pdf.
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The dynamics of partially molten regions of the Earth's mantle are studied using a combination of theoretical, experimental, and numerical techniques. The physical model is based on experimental observations of partially molten ultramafic rocks and incorporates two elements: buoyancy-driven porous flow of magma through a viscously deformable matrix, and buoyancy-driven circulation of the whole rock.
The first element of this model is analogous to buoyancy-driven pipe flow of a liquid through a denser and more viscous wall fluid. Laboratory experiments on this system illustrate the phenomenon of solitary waves. These are waves of larger pipe radius that ascend a uniform pipe of smaller radius. The waves are very nearly conserved in collisions. These, and the corresponding waves of higher porosity that arise in one-dimensional porous flow, are characterized further by analysis and numerical experiments.
The full system, incorporating circulation in a multidimensional porous medium, also displays solitary waves governed by the same basic processes as the one-dimensional waves. Analysis and numerical experiments show that the multidimensional waves have a circular or spherical form.
A possible natural manifestation of this fluid dynamical phenomenon is in igneous processes. Magmons, as the waves are called in that setting, probably have wavelengths of kilometers and velocities of centimeters per year. Magma ascent in magmons may account for episodicity in igneous emplacement. Also, a magmon can collect and mobilize a small degree of partial melt without disturbing its geochemical signature. In a partially molten region the characteristic wavelength of magmons will always be superimposed on that of large scale variations in porosity.
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Küppers, Ulrich [Verfasser]. « Nature and efficiency of pyroclast generation from porous magma : insights from field investigations and laboratory experiments / vorgelegt von Ulrich Küppers ». 2005. http://d-nb.info/978063759/34.
Texte intégralLivres sur le sujet "Porous magma"
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Gasparro Sevilha Greco, Patrícia, et André Del Grossi Assumpção. Reflexões sobre uma nova hermenêutica constitucional : leis, valores e sociedade. Sous la direction de Raul Greco. Vox Littera Publicações, 2022. http://dx.doi.org/10.55647/012022.
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A sociedade vem sofrendo modificações em suas relações intersubjetivas em velocidades jamais vistas na história da humanidade. Neste cenário, deve-se considerar o intercâmbio entre diferentes culturas, com os mais variados níveis de desenvolvimentos econômicos e tecnológicos, somados às plataformas digitais de comunicação e, ainda, às mudanças paradigmáticas no fluxo informacional. O ethos exigido tanto na condução das coisas públicas pelo Estado, quanto na vida cívica do cidadão é, diuturnamente, testado com variantes axiológicas crescentes e que, a um só tempo, podem ser o instrumento de pacificação necessária aos conflitos derivados da convivência social, como, ainda, podem ser objeto destas mesmas pretensões resistidas. A fórmula para se conseguir manejar toda sorte de situações oriundas desta dinâmica acelerada não mais se repousa na mera subsunção das normas aos fatos, demandando-se, em verdade, ao Direito, uma hermenêutica mais complexa, rica em soluções que possam se dar em tempo mínimo. É neste sentido que se busca um novo olhar que resista a um positivismo frio e, ainda, a um relativismo perigoso e subjetivista, o qual pode seduzir um olhar incauto e virar um cheque em branco para autoritarismos. A dosagem reside na virtude aristotélica do meio termo, fugindo-se de fórmulas prontas, as quais serão obsoletas em questão de pouco tempo, como, ainda, reside no afastamento de radicalismos que ignorem as mutações na sociedade. A hermenêutica, deste modo, apresenta-se como o meio necessário para trazer as soluções demandadas, carreando nesta busca resolutiva a ponderação de valores, a noção de justiça, a obediência à democracia e à lei (sobretudo à Constituição) e a busca ao bem comum. Com base em pensadores como Schleiermacher, Ausubel, Gadamer, dentre outros, podemos ver a hermenêutica jurídica como a busca de um significado normativo que desvele uma universalidade e, portanto, a verdade, o bom e o justo. A lei, sob a égide hermenêutica, não é mais um comando fechado em si, mas pertencente a um sistema que envolve, ainda, valores, princípios e tem objetivos claros a serem atingidos e que, nem sempre, resultam de sua aplicação imediata, mas dos desdobramentos que dela possam advir. A presente obra propõe aos seus autores uma releitura de temas que demandem um olhar hermenêutico que integre este cabedal de variantes altamente mutáveis, dado o aumento da complexidade das relações humanas. Assim, o tônus da obra é o de chamar a atenção para as causas do tratamento normativo, ou seja, porque certo tema tem relevância a ponto de ser regrado pela lei, e de como sua resolução demanda, consequentemente, um processo integrativo dos atos e fatos jurídicos aos valores constitucionais que orientarão a interpretação universalista desta mesma norma. O fenômeno de mutação constitucional, por exemplo, é um exemplo vívido de como uma mesma previsão legal pode ter sua aplicação variada conforme a hermenêutica que se lança sobre ele, com a lente axiológica de seu tempo e espaço. Não é por menos que normas-princípio são extraídas do texto constitucional sem que haja menção expressa sobre elas. É deste exercício hermenêutico que todos os ramos do Direito, irradiados a partir da Carta Magna, recebem a carga interpretativa mais apta a resolver os problemas no seio social, buscando-se, desta maneira, a almejada justiça.
Chapitres de livres sur le sujet "Porous magma"
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Petford, Nick. « Porous Media Flow in Granitoid Magmas : An Assessment ». Dans Flow and Creep in the Solar System : Observations, Modeling and Theory, 261–86. Dordrecht : Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-015-8206-3_17.
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Lundstrom, C. C., X. Lin, K. Brueckel, C. Campe, X. Nan, K. Ortega, P. Akrie, M. Yu et S. Marshak. « New mechanism for forming thick granitic continental crust at Phanerozoic convergent margins ». Dans In the Footsteps of Warren B. Hamilton : New Ideas in Earth Science. Geological Society of America, 2022. http://dx.doi.org/10.1130/2021.2553(20).
Texte intégralRésumé :
ABSTRACT Phanerozoic continental subduction zones have produced thick continental crust composed almost entirely of granitoid plutons. While ideas about how plutons form have evolved from models that envisioned large, highly molten magma bodies, the exact processes involved remain debated. Geochronology and seismology have led to the view that plutons form by incremental emplacement; stacked sills represent one type of incremental model whereby granitoids grow top-down by sills underplating their predecessor. Still, many questions remain unanswered, including why sill-like contacts are not often seen in more mature plutons, why the mafic residuum is not observed with many granitoid plutons, why some plutons are compositionally zoned (and others are not), and why geochemical characteristics of intrusions systematically change during magmatic cycles. Here, we propose a hypothesis for the construction of batholiths by amalgamation of plutons formed in a two-stage process. During stage 1, intermediate-composition sills underplate previous sills, forming a moving reaction zone mafic complex that produces a thickening granitoid as the process moves downward. The top of this mafic complex also releases a water-rich, low-temperature silicate liquid (LTSL), which begins ascent by reactive porous flow. During stage 2, the upward flux of LTSL further differentiates the overlying granitoids, increasing silica by 5%–10% and resulting in linear “mixing-like” behavior on Harker diagrams. Multiple plutons building downward in a magmatic cycle thicken the crust, leading to garnet gabbro mafic complexes forming at ~20 km depth. Their high density leads to delamination and net silicification of continental crust. The continuous flux of LTSL up through the arc crust can explain many geochemical spatial-temporal trends found in magmatic cycles, including Pb isotope evolution and increasing Fe3+, and provides a mechanism for addition of water to the upper crust, leading to sustained volcanism through time.
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Van Haeperen, Françoise. « Portus. Lieu de culte de Mater Magna (localisation incertaine) ». Dans Fana, templa, delubra. Corpus dei luoghi di culto dell'Italia antica (FTD) - 6. Collège de France, 2019. http://dx.doi.org/10.4000/books.cdf.6835.
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Goti, Jaime Malamud. « ¿CASTIGAR LA MAGIA NEGRA VUDÚ SOLO PORQUE MATA ? : ». Dans Homenaje a Genaro R. Carri? ?, 31–50. Universidad del Externado de Colombia, 2017. http://dx.doi.org/10.2307/j.ctv1ddcw76.6.
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Furbish, David Jon. « Introduction ». Dans Fluid Physics in Geology. Oxford University Press, 1997. http://dx.doi.org/10.1093/oso/9780195077018.003.0005.
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Fluids are involved in virtually all geological processes. Obvious examples are phenomena occurring at Earth’s surface in which fluid flow is a highlight: the flow of a lava stream, the play of a geyser, river flow and wind currents, the swash and backswash on a beach. Also obvious are phenomena that occur in the presence of fluid flows, such as sediment motion. Less obvious, but readily imaginable in terms of their behaviors, are fluid motions occurring within Earth’s crust: flows of magma and ground water, and expulsion of brines from sediments during compaction. In addition, a bit of reflection will recall a host of phenomena in which fluid behavior, although not the highlight, may nonetheless take on a significant role: initiation of landslides, seismic activity, glacier movement, taphonomic organization, and fracture mechanics. With these should be considered instances in which the geological material containing a fluid can influence its fundamental behavior at a molecular scale. An example is flow through very small rock pores, where molecular forces interacting among fluid molecules and pore surfaces can lead to a structural arrangement of the fluid molecules such that their mechanical behavior is unlike that which occurs in large pores, where the bulk of the fluid is “far” from pore surfaces. It is thus understandable that to describe many geologic phenomena requires knowing how fluids work. It is also natural to begin by considering how fluids behave in a general way, then in turn, how they are involved in specific geological processes. There are several approaches for describing fluids and their motions, and the choice of one, or some combination, depends on the sort of insight desired as well as the specific problem being considered. Fluid statics, as the name implies, involves considering the properties of fluids that are at rest in some inertial frame of reference. Note that this frame of reference may actually be moving relative to the Earth frame of reference, so long as the fluid motion is like that of a rigid body. An important example of our use of fluid statics will be in developing the hydrostatic equation, which formalizes how fluid pressure varies with depth.
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Furbish, David Jon. « Thermodynamic Properties of Fluids ». Dans Fluid Physics in Geology. Oxford University Press, 1997. http://dx.doi.org/10.1093/oso/9780195077018.003.0008.
Texte intégralRésumé :
Fluid behavior in many geological problems is strongly influenced by extant thermal conditions and flow of heat. Recall, for example, that the coefficient A in Glen’s law for ice (3.40) varies over three orders of magnitude with a change in temperature of 50 °C. The effect of this is to strongly modulate the rate of ice deformation for a given level of stress. Recall further that we introduced several fluid properties—fluid compressibility, for example—where we asserted that our purely mechanical developments were incomplete inasmuch as they did not treat effects of varying temperature. The reasons for this will become clear in this chapter, including why it is difficult to maintain isothermal conditions when the pressure of a fluid is changing. In addition, many geological problems involve fluid flows that are induced by effects of variations in thermal conditions over time and space. These include buoyancy-driven convective motions that arise from variations in fluid density associated with variations in temperature (Chapter 16). Specific examples include convective overturning in a magma chamber, which can significantly influence how crystallizing minerals are distributed; convective circulations of water and chemical solutions in a sedimentary basin, which can influence where rock materials are dissolved and where they are precipitated as cements within pores; and convective circulation of water within the active layer above seasonally frozen ground, which may influence where patterned ground develops in periglacial environments. These processes, and viscous flows in general, invariably involve conversions of mechanical energy to heat, or vice versa. So in considering problems involving heat energy, we should recall from introductory chemistry and physics that such conversions can involve work performed on the fluid or its surroundings, and anticipate that the effects of this ought be manifest in fluid behavior. This chapter, then, is concerned with fluid pressure, temperature, and density, and how these variables are related to heat, mechanical energy, and work. We will note in digressions how these macroscopic concepts, like fluid viscosity, often have clear interpretations at a molecular scale based on kinetic theory of matter.
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Bonilla Olaya, María del Pilar. « Itinerario diagnóstico de pacientes con cáncer de próstata en población vulnerable en Colombia una realidad vivida ». Dans Formación y manejo del cuerpo desde la educación para la salud y la antropología, 105–20. Fundación Universitaria Juan N. Corpas, 2020. http://dx.doi.org/10.26752/9789589297445.6.
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El cáncer en todas sus demostraciones se ha convertido a nivel global en la patología crónica no transmisible más común, después de la hipertensión arterial y la diabetes mellitus tipo 2, teniendo alcances como en el cáncer de mama que tiene una de las tasas de mortalidad más altas en neoplasias en el mundo. El cáncer de próstata es un problema de salud pública, que aqueja a hombres desde los 50 años sin distinción de raza, religión, orientación sexual o cultura. Muchos han sido los inconvenientes para el diagnóstico de cáncer de próstata en Colombia, desde las dificultades para el acceso a los servicios en salud, ya sea por poblaciones lejanas con características demográficas que dificultan la llegada de los entes de salud o simplemente por las características sociales y culturales que hacen de nuestra población masculina machista, la limitada capacidad de respuesta que se oferta para el tratamiento: acceder a la atención especializada es difícil, porque se requieren de muchos trámites con la EPS y no se puede lograr el tratamiento oportuno. A esto se suma el desconocimiento que la población masculina tiene de esta enfermedad que muy pocos conocen del curso natural para evitar situaciones de riesgo y prevenir la mortalidad derivada del cáncer de próstata, y principalmente en lo relacionado con las pruebas diagnósticas y la sintomatología. Conocer las perspectivas y aspectos similares encontrados en la población, teniendo en cuenta las dificultades que puedan presentarse en el sistema de salud colombiano para su diagnóstico y tratamiento; describiendo de esta forma las barreras y problemas frecuentes encontradas por la población diagnosticada.
Actes de conférences sur le sujet "Porous magma"
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Sicola, Stefania, Alessandro Vona, Claudia Romano, Amy G. Ryan et James K. Russell. « The Rheological Behaviour of Porous Magmas : Bubbles vs. Vesicles ». Dans Goldschmidt2020. Geochemical Society, 2020. http://dx.doi.org/10.46427/gold2020.2380.
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Pazini, Heloísa Martendal, Dylson Junyor Neckel Linden, Isabella Cristina Michelon et Letícia Bortolazzi. « TIPOS HISTOLÓGICOS PREVALENTES DO CÂNCER DE MAMA NA REGIÃO OESTE DO PARANÁ ». Dans I Congresso Nacional Multidisciplinar de Oncologia On-line. Revista Multidisciplinar em Saúde, 2021. http://dx.doi.org/10.51161/rems/1997.
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Introdução: Este artigo tem como objetivo elencar e comparar os tipos histológicos do câncer de mama na região Oeste do Paraná, composta pelas microrregiões Cascavel, Foz do Iguaçu e Toledo no período de 2015 a 2019. Ob: Serão observados estatisticamente os números de casos de Cânceres de Mama por tipo histológico que se mostram mais prevalentes na região oeste do Paraná. Com a coleta dos dados e a observação dos tipos histológico do câncer de mama, é possível que sejam elaborados planos quanto à prevenção e diagnóstico precoce. MATERIAL E MÉTODOS: Para o levantamento de dados foi utilizada a plataforma do Instituto Nacional de Câncer onde são disponibilizados dados em forma de tabela através do Integrador RHC (Registro Hospitalar de Câncer) comparando número de casos por tipo do caso e tipo histológico. RESULTADOS: Dos dados coletados foi verificado que em Cascavel, o carcinoma ductal infiltrante apresentou 996 casos, carcinoma lobular SOE apresentou 37 casos, o carcinoma sem outra especificação (SOE) apresentou 29 casos. Foz do Iguaçu tem como carcinoma prevalente o carcinoma ductal infiltrante com 360 casos, o carcinoma intraductal não infiltrante com 19 casos e o carcinoma SOE com 11 casos. Já Toledo não apresentou casos de câncer de mama. CONCLUSÃO: Visto que no oeste do Paraná a maioria das mulheres foram diagnosticadas com câncer de mama entre os 55-59 anos, o planejamento de estratégias para a detecção precoce faz-se fundamental nesta região. É importante orientar essa população sobre a prevenção primária e realização de exames preventivos antes dos 50 anos, principalmente em casos de histórico familiar da doença. A importância do autoexame, que é feito com a palpação mensal das mamas, e o exame clínico das mamas são fundamentais porque podem detectar alguns sinais ou alterações nas mamas, como: abaulamentos, retração e secreção nos mamilos, vermelhidão, e nódulos.
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AlJanahi, Ahmed, Feras Altawash, Hassan AlMannai, Sayed Abdelredy, Hamed Al Ghadhban, Eyad Ali, Atanu Bandyopadhyay et al. « Geomechanical Model as the Key Step to Proppant Fracturing Success in Shallow Carbonate Reservoir of Bahrain ». Dans Abu Dhabi International Petroleum Exhibition & Conference. SPE, 2021. http://dx.doi.org/10.2118/207635-ms.
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Abstract Geomechanics play an important role in stimulation design, especially in complex tight reservoirs with very low matrix permeability. Robust modelling of stresses along with rock mechanical properties helps to identify the stress barriers which are crucial for optimum stimulation design and proppant allocation. Complex modeling and calibration workflow showcased the value of geomechanical analysis in a large stimulation project in the Ostracod-Magwa reservoir, a complicated shallow carbonate reservoir in the Bahrain Field. For the initial model, regional average rock properties and minimum stress values from earlier frack campaigns were considered. During campaign progression, advanced cross dipole sonic measurements of the new wells were incorporated in the geomechanical modeling which provided rock properties and stresses with improved confidence. The outputs from wireline-conveyed microfrac tests and the fracturing treatments were also considered for calibration of the minimum horizontal stress and breakdown pressure. The porepressure variability was established with the measured formation pressure data. The geomechanically derived horizontal stresses were used as input for the frack-design. Independent fracture geometry measurements were run to validate the model. The poro-elastic horizontal strain approach was taken to model the horizontal stresses, which shows better variability of the stress profile depending on the elastic rock properties. The study shows variable depletion in porepressure across the field as well as within different reservoir layers. The Ostracod reservoir is more depleted than Magwa, with porepressure values lower than hydrostatic (∼7 ppg). The B3 shale layer in between the Magwa and Ostracod reservoirs is a competent barrier with 1200-1500psi closure pressure. The closure pressures in the Ostracod and Magwa vary from 1000-1500psi and 1100-1600psi, respectively. There is a gradual increasing trend observed in closure pressure in Magwa with depth, but no such trend is apparent in the shallower Ostracod formation. High resolution stress profiles help to identify the barriers within each reservoir to place horizontal wells and quantify the magnitude of hydraulic fracture stress barriers along horizontal wells. The geomechanical model served as a key part of the fracturing optimization workflow, resulting in more than double increase in wells productivity compared to previous stimulation campaigns. The study also helped to optimize the selection of the clusters depth of hydraulic fracturing stages in horizontal wells. The poroelastic horizontal strain approach to constrain horizontal stresses from cross dipole sonic provides better variability in the stress profile to ultimately yield high resolution. This model, calibrated with actual frac data, is crucial for stimulation design in complex reservoirs with very low matrix permeability. The geomechanical model serves as one of the few for shallow carbonates rock in the Middle East region and can be of significant importance to many other shallow projects in the region.
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Souza, Michelle Freitas de, Fatima Helena Do Espirito Santo, Ana Paula De Magalhaes Barbosa et Fabio Ricardo Dutra Lamego. « O ENFERMEIRO E O ACOLHIMENTO DE PACIENTES NO PRÉ OPERATÓRIO DE CÂNCER DE MAMA : RELATO DE EXPERIÊNCIA ». Dans II Congresso Brasileiro de Saúde On-line. Revista Multidisciplinar em Saúde, 2021. http://dx.doi.org/10.51161/rems/1517.
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Introdução: A Política Nacional de Humanização define acolher como reconhecer o que o outro traz como legítima e singular necessidade de saúde. Ele é construído de forma coletiva, a partir da análise dos processos de trabalho e tem como objetivo a construção de relações de confiança, compromisso e vínculo entre profissionais e pacientes tornando-se em uma rede socioafetiva. O câncer de mama é o mais temido entre as mulheres, porque ao receberem o diagnóstico significa incertezas, medo da morte, mutilação, distúrbio de imagem e depressão. Objetivo: Descrever a experiência da atuação do enfermeiro no acolhimento de pacientes em pré operatório de câncer de mama. Metodologia: Trata-se de um relato de experiência de uma enfermeira da clínica cirúrgica feminina de um Hospital Universitário no Rio de Janeiro, no período de janeiro a abril de 21. Resultados: O acolhimento acontece quando a paciente é admitida no setor de clínica cirúrgica feminina (CCF). O enfermeiro entrevista e colhe o histórico da paciente, logo após oferta uma escuta qualificada, apoio psicológico e emocional, fortalece que ela é capaz de vencer as adversidades da doença, explica a importância do tratamento precoce e do auto cuidado. Conclusão: O acolhimento vem ao encontro do cuidado humanizado cujos elementos são a empatia, a compaixão e o respeito à dignidade da pessoa. A partir da relação dialógica e escuta ativa o enfermeiro favorece que a paciente se sinta mais segura e confiante para enfrentar o diagnóstico e superar os desafios do tratamento do câncer repercutindo na recuperação e conscientização quanto à importância do auto cuidado.
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FELIN, GIANCARLLO DANEZI, GIULLIANO DANEZI FELIN, CAROLLINA DANEZI FELIN, FELLIPE DANEZI FELIN et IZABELLA PAZ DANEZI FELIN. « GENÉTICA MOLECULAR DO CÂNCER DE MAMA : IMPLICAÇÕES NA CLASSIFICAÇÃO MOLECULAR E NO ALVO TERAPÊUTICO ». Dans I Congresso Nacional de Pesquisas e Estudos Genéticos On-line. Revista Multidisciplinar em Saúde, 2022. http://dx.doi.org/10.51161/geneticon/9011.
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Introdução: Antigamente a classificação do câncer de mama (CM) era estabelecida exclusivamente através de critérios histopatológicos e seu tratamento direcionado pelo estadiamento. Atualmente foi incorporada uma classificação molecular o que determinou novas possibilidades antineoplásicas. Nesse sentido, o estudo da genética molecular do CM é altamente relevante, pois além de direcionar sua classificação e tratamento, relaciona-se à neoplasia mais incidente nas mulheres no mundo todo. Objetivos: Identificar a genética molecular do câncer de mama e sua implicação na classificação e no alvo terapêutico. Metodologia: Revisão de literatura através de pesquisa na base de dados MEDLINE, via PubMed, utilizando-se os termos DeCS/ MeHS: "breast cancer" [and] “molecular classification" [and] “targeted therapy”. Aplicados filtros de busca: “textos completos gratuitos” e “últimos 5 anos”. Encontrados 10 resultados e incluídos 3 nesse estudo. Os critérios de elegibilidade foram todos os artigos coincidentes com tema proposto, conforme os filtros e termos de busca. Excluiu-se 7 artigos por não contemplarem os critérios elegíveis. Realizada extração de dados, análise dos resultados e redação dessa revisão. Resultados: A genética molecular do CM é heterogênea, o que permite classifica-lo conforme alterações da expressão gênica dos receptores hormonais (RH), do receptor de fator de crescimento epidérmico tipo 2 (HER2) e do índice de proliferação celular Ki67/MIB-1, nos subtipos: luminal A (LA), luminal B (LB), HER2 e triplo negativo (TN). Os LA e parte dos LB superexpressam RH, mas não o HER2. Nos LA o Ki67/MIB-1 é menor que 14%, enquanto nos LB é igual ou superior a 14%. Os LA e LB que hiperexpressam RH, mas não expressam HER2, independente do Ki67, devem receber bloqueio hormonal (BH), mas a terapia alvo molecular (TAM) é contraindicada. Alguns LB são triplo positivos porque hiperexpressam RH e HER2, esses tem indicação combinada de BH e TAM. O subtipo HER2 usa exclusivamente TAM, enquanto que o TN não responde a nenhuma dessas terapias de BH e TAM. Felizmente, estudos recentes demonstraram que 25% dos TN respondem à imunoterapia (IMT). Conclusão: Foi possível identificar a genética molecular do câncer de mama e sua importante implicação na determinação da classificação molecular e no direcionamento do alvo terapêutico.
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AlJanahi, Ahmed, Feras Altawash, Omar Matar, Hassan AlMannai, Atanu Bandyopadhyay, Florian Karpfinger, Vladimir Stashevskiy et Alexey Yudin. « Geomechanical Model as the Key Step to Proppant Fracturing Success in Shallow Carbonate Reservoir of Bahrain ». Dans SPE Middle East Oil & Gas Show and Conference. SPE, 2021. http://dx.doi.org/10.2118/204853-ms.
Texte intégralRésumé :
Abstract Geomechanics plays an important role in stimulation design especially in complex tight reservoirs with very low matrix permeability. Robust modelling of horizontal stresses along with rock mechanical properties helps to identify the stress barriers which are crucial for optimum stimulation design and proppant allocation. A comprehensive modeling and calibration workflow showcased the value of geomechanical analysis in large stimulation project of Ostracod-Magwa, a compex shallow carbonate reservoir in the Awali onshore field, Bahrain. For the initial Geomechanical model regional average rock properties and minimum stress values from earlier frac campaigns were considered. During campaign progression, advanced cross dipole sonic measurements of the new wells were incorporated in the geomechanical modeling which provided rock properties and stresses with improved confidence. The outputs from wireline-conveyed microfrac tests and the fracturing treatments were also considered for calibration of the minimum horizontal stress and breakdown pressure. The porepressure variability was established with the measured formation pressure data. The geomechanically derived horizontal stresses and elastic properties were used as input for the frac-design. Independent fracture geometry measurements were run to validate the model. The poro-elastic horizontal strain approach was used to model the horizontal stress magnitudes. This approach shows variability of the stress profile depending on the elastic rock properties. The study shows variable depletion in porepressure across the field as well as within different reservoir layers of Magwa and Ostracod. Ostracod is more depleted compared to the Magwa reservoir with porepressure values below hydrostatic (~7 ppg). The B3 shale layer between Magwa and Ostracod reservoirs could be established as a stress barrier with 1200-1500 psi closure pressure. The closure pressure in Ostracod varies in the range of 1000-1500 psi while the range in Magwa is 1100-1600 psi. In the Magwa reservoir a gradual increase of closure pressure with depth is observed, while no such trend is apparent in the shallower Ostracod formation. Geomechanical models served as a key input of the integral frac optimization workflow that resulted in increasing the well productivity by more then double compared to previous stimulation campaigns. The poroelastic horizontal strain model to predict the horizontal stresses from cross-dipole sonic data provides higher stress variability and ultimately yields a high resolution stress profile. This model calibrated with direct closure pressure measuremtns is crucial for successful stimulation design in complex reservoirs with very low matrix permeability. Geology Overview and Problem Statement The Ostracod and Magwa formations are shallow reservoir development targets over the Awali field in the Kingdom of Bahrain. The depth of these reservoir ranges from 1400-1800 ft TVDSS and are represented by shallow marine limestones, which are composed of bioclastic, packstone/wackestone with occasional dolomites, chert, lime mudstone, and scarce pyrite. The reservoirs are represented by a triple porosity system which consists of matrix porosity, secondary natural fractures porosity and bioturbation enhanced porosities that can be associated with dissolution (micro-vugs). The Ostracod reservoir exhibits intense natural fractures towards the base whereas the upper part of the reservoir is associated with a combination of both, vugs and natural fractures. The section is heavily interbedded with numerous shale barriers which gives an average net-to-grows (NTG) ~ 35% with gross thickness ~150-200 ft. On the other hand, Magwa reservoir is represented by thicker limestones where the secondary porosity is mostly represented by bioturbated units resulting in a higher average NTG ~75% with gross thickness up to 150 ft. The reservoirs are heavily faulted, ~140 faults identified by manual seismic interpretation and more than 800 faults observed on the well log data by missing/repeating sections over total of ~2000 wells. Production from the reservoirs started from early 1960's mainly by perforation of watered/gas out wells from the lower producing horizons, followed by active drilling camping in 2011-2015 ~250 wells and minor drilling in 2016-2019. New drilled wells had a so-called "flash" production exhibits a high oil production rates followed by rapid production decline with the long low rate tail production. Long production history and active development drilling however did not provide good recovery factor for the reservoirs – after more than 55 years of development the current recovery factor is ~5%. At the same time, a recent new well drilling campaign provided only marginal economic production results, which opened the area for production enhancement opportunities. Based on historical production analysis and numerous acid stimulations performed on the field it was concluded that acid stimulations demonstrated a good immediate production response however the effect was not lasting more than 3-6 months (AlJanahi et al. 2020). And one of the key contributors to this effect on top of the natural depletion was the geological structure of target reservoirs – the reservoirs are not clean carbonates – they are heavily intercalated with shales. The effect of increased connected reservoir volume to the wellbore was not lasting for long due to possible fine migration and did not provide enough vertical connectivity and good lateral extension. Based on above observations, hydraulic fracturing was considered as an option for the production enhancement which could potentially provide good lateral and vertical reservoir connectivity with the wellbore and would not be heavily affected by time, or at least the effect of operation will last longer than observed historically. However, a hydraulic fracturing campaign was performed on the field in the period 2010-2011, despite good production results the incremental production after hydraulic fracturing was insignificant comparing with the wells without the fracturing. After analyzing observed results coupled with post fracturing evaluation it was concluded that the actual achieved hydraulic fracture geometry was not enough to outpace non fractured wells in these reservoirs. Based on numerical simulation studies it was concluded that the higher effective half-length and higher conductivity of a hydraulic fracture could provide better production results with much longer effect in time. Therefore, the question of achievable fracture geometry, its distribution laterally and vertically was pushed into the forefront.
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Folgado, Jéssica Diniz, Bruna Taiane Gomes Copetti, Naiara Pinheiro Gonçalves et Helizandra Simoneti Bianchini Romanholo. « CUIDADOS DE ENFERMAGEM NO PREPARO DAS MAMAS PARA O ALEITAMENTO MATERNO : REVISÃO INTEGRATIVA ». Dans II Congresso Nacional Multidisciplinar em Enfermagem On-line. Revista Multidisciplinar em Saúde, 2021. http://dx.doi.org/10.51161/rems/2467.
Texte intégralRésumé :
Introdução: o enfermeiro exerce um papel importante na assistência à saúde da mulher durante o pré-natal, parto e puerpério, sendo fundamental orientar cuidados que visam preparar as mamas para o aleitamento materno, pois evita complicações com as mamas e garante a promoção do aleitamento materno, trazendo benefícios para mãe e filho. Objetivo: descrever os cuidados de enfermagem que são eficazes no preparo da mama para o aleitamento materno. Método: trata-se de um artigo de revisão integrativa, foram adotadas como fonte de informação as bases de dados eletrônicas vinculadas a BVS (Biblioteca Virtual em Saúde) e não eletrônicas disponíveis na biblioteca do Centro Universitário Unifacimed, tendo como critérios de inclusão: estudos na íntegra e de acesso gratuito; estudos publicados de janeiro de 2010 à julho 2021; estudos com mulheres sem limitação de idade e estudos publicados na língua portuguesa e inglesa. Critérios de exclusão: estudos duplicados; indisponíveis na íntegra e os estudos que não contemplavam o objetivo da pesquisa. O levantamento das referências ocorreu em setembro e outubro de 2021, para o levantamento de dados foram utilizados os descritores: “cuidados de enfermagem”, “aleitamento materno”, “pré-natal” e “período pós-parto”, no qual foi identificado 1056 referências, onde fizeram parte da amostra 09 referências. Resultados: das referências analisadas 07 (77,7%) mencionou, que o banho de sol nas mamas é o cuidado mais instrutivo para a gestante no preparo das mamas antes do parto e a indicação do banho de luz, citado por 03 (33,3%) autores reafirmar a importância do fortalecimento do tecido mamário, o banho de sol e o banho de luz desenvolvem funções semelhantes pois podem fortalecer as mamas, evitar possíveis complicações mamárias e contribuir na produção de leite e 05 (55,6%) referem que pomadas, sabonetes, cremes e óleos são contra indicados durante o preparo das mamas porque afinam a espessura dos tecidos das mamas e removem a proteção natural do mamilo. Conclusão: concluiu-se que é de suma importância o auxílio da enfermagem na preparação da mama durante o pré-natal. Pois o aleitamento materno é a mais sabia estratégia natural de vinculo, afeto, proteção e nutrição entre a mãe e o bebê.