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Artigos de revistas sobre o assunto "Water masses formation"
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Said, M. A., e A. M. Karam. "On the formation of the intermediate water masses off the Egyptian Mediterranean coast". Archiv für Hydrobiologie 120, n.º 1 (12 de dezembro de 1990): 111–22. http://dx.doi.org/10.1127/archiv-hydrobiol/120/1990/111.
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Kawamura, Hideyuki, Jong-Hwan Yoon e Toshimichi Ito. "Formation rate of water masses in the Japan sea". Journal of Oceanography 63, n.º 2 (abril de 2007): 243–53. http://dx.doi.org/10.1007/s10872-007-0025-6.
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Thompson, Lu Anne, e Wei Cheng. "Water Masses in the Pacific in CCSM3". Journal of Climate 21, n.º 17 (1 de setembro de 2008): 4514–28. http://dx.doi.org/10.1175/2008jcli2280.1.
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Abstract An examination of model water masses in the North Pacific Ocean is performed in the Community Climate System version 3 (CCSM3) and its ocean-only counterpart. While the surface properties of the ocean are well represented in both simulations, biases in thermocline and intermediate-water masses exist that point to errors in both ocean model physics and the atmospheric component of the coupled model. The lack of North Pacific Intermediate Water (NPIW) in both simulations as well as the overexpression of a too-fresh Antarctic Intermediate Water (AAIW) is indicative of ocean model deficiencies. These properties reflect the difficulty of low-resolution ocean models to represent processes that control deep-water formation both in the Southern Ocean and in the Okhotsk Sea. In addition, as is typical of low-resolution ocean models, errors in the position of the Kuroshio, the North Pacific subtropical gyre western boundary current (WBC), impact the formation of the water masses that form the bulk of the thermocline as well as the properties of the NPIW. Biases that arise only in the coupled simulation include too-salty surface water in the subtropical North Pacific and too deep a thermocline, the source of which is the too-strong westerlies at midlatitudes. Biases in the location of the intertropical convergence zone (ITCZ) and the southern Pacific convergence zone (SPCZ) lead to the opposite hemispheric asymmetry in water mass structure when compared to observations. The atmospheric component of the coupled model acts to compound most ocean model biases.
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Poulos, Serafeim E. "Water Masses of the Mediterranean Sea and Black Sea: An Overview". Water 15, n.º 18 (7 de setembro de 2023): 3194. http://dx.doi.org/10.3390/w15183194.
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This overview presents the different water masses present in the various primary and secondary marine regions of the Mediterranean Sea and Black Sea, providing information on their main physical characteristics (i.e., temperature, salinity, density), the water depths at which they have been observed and the processes involved in their formation. There is a characteristic difference in the overall hydrology of the Mediterranean Sea compared to the Black Sea, in terms of the number and characteristics of water masses and their formation processes, although they form a single (integrated) marine system. This difference is explained by the limited communication between the two seas through the Sea of Marmara and its straits (the Dardanelles and Bosporus) and by the fact that the Mediterranean Sea is a condensation basin while the Black Sea is a dilution basin; therefore, the deficit of water in the former is compensated by the inflow of Atlantic waters, while the surplus in the latter outflows to the Aegean Sea. In total, 21 different water masses have been identified in the Mediterranean Sea (excluding the Straits of Gibraltar and the Sea of Marmara) compared to the 5 water masses identified in the Black Sea (excluding the Sea of Azov). This large number of water masses is attributed to coastal morphology (i.e., presence of straits) and submarine relief (i.e., deep basin separated by shallow sills) and different formation processes.
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Nielsen, Morten Holtegaard, Torben Vang e Lars Chresten Lund-Hansen. "Internal hydraulic control in the Little Belt, Denmark – observations of flow configurations and water mass formation". Ocean Science 13, n.º 6 (18 de dezembro de 2017): 1061–75. http://dx.doi.org/10.5194/os-13-1061-2017.
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Abstract. Internal hydraulic control, which occurs when stratified water masses are forced through an abrupt constriction, plays an enormous role in nature on both large and regional scales with respect to dynamics, circulation, and water mass formation. Despite a growing literature on this subject surprisingly few direct observations have been made that conclusively show the existence of and the circumstances related to internal hydraulic control in nature. In this study we present observations from the Little Belt, Denmark, one of three narrow straits connecting the Baltic Sea and the North Sea. The observations (comprised primarily of along-strait, detailed transects of salinity and temperature; continuous observations of flow velocity, salinity, and temperature at a permanent station; and numerous vertical profiles of salinity, temperature, fluorescence, and flow velocity in various locations) show that internal hydraulic control is a frequently occurring phenomenon in the Little Belt. The observations, which are limited to south-going flows of approximately two-layered water masses, show that internal hydraulic control may take either of two configurations, i.e. the lower or the upper layer being the active, accelerating one. This is connected to the depth of the pycnocline on the upstream side and the topography, which is both deepening and contracting toward the narrow part of the Little Belt. The existence of two possible flow configurations is known from theoretical and laboratory studies, but we believe that this has never been observed in nature and reported before. The water masses formed by the intense mixing, which is tightly connected with the presence of control, may be found far downstream of the point of control. The observations show that these particular water masses are associated with chlorophyll concentrations that are considerably higher than in adjacent water masses, showing that control has a considerable influence on the primary production and hence the ecosystem in the area.
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Kovalev, S. N. "PECULIARITIES OF WATER AND SEDIMENT RUN-OFF IN A RAVINE AT THE BEGINNING OF THE FLOOD". Bulletin of Udmurt University. Series Biology. Earth Sciences 33, n.º 3 (29 de setembro de 2023): 328–34. http://dx.doi.org/10.35634/2412-9518-2023-33-3-328-334.
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The formation of water and sediment run-off in a ravine in different natural zones with humid climate begins before the main flood event. The type of spring (advective or solar type) determines the volume of water and sediment run-off, which is formed depending on the volume of snow masses in the ravine and in its catchment area. The density parameters of the snow mass, formed depending on the alternation of thaws and snow compaction under the influence of wind, determine the nature of the water flow through the snow mass or under the snow. At the same time, with the advective type of spring, the water flow does not produce any erosive work. The solar type of spring corresponds to active erosion of the sides and top of the ravine with a slight impact on the thalweg. The purpose of this work is to show the role of snow masses in the catchment and in the ravine and their influence on the formation of water and sediment run-off in the pre-water period with different types of spring. The work was carried out on the basis of observations during field work in different regions of the country and showed that the flow of water in the ravine at the initial stage of high water depends on the conditions for the formation of snow masses in the ravine. It has been established that snow masses accumulated during winter have an ambiguous effect on the water flow in the pre-water area and largely depend on specific weather conditions and anthropogenic impact on the gully catchment.
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Antipov, N. N., e A. V. Klepikov. "Interannual variability of water masses in the area of bottom water formation in Рrydz Вay". Arctic and Antarctic Research, n.º 3 (30 de setembro de 2017): 87–106. http://dx.doi.org/10.30758/0555-2648-2017-0-3-87-106.
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The results of field studies of the processes of Antarctic Bottom Water formation conducted in the period from 2004 to 2016 in the Prydz Bay of the Commonwealth Sea is discussed. During this period the oceanographic observations along the 70° E section, crossing the shelf and the continental slope, were repeated nine times. In this area in the austral summer of 2004 during the AARI expedition on the r/v “Akademik Fedorov” the process of formation of bottom water has been recorded for the first time. A further study of the structure and characteristics of water masses on this section and in the adjacent area confirmed the regularity of these processes during the summer period. At the same time, a significant interannual variability of the structure, characteristics, and mechanisms of distribution of the main water masses in the section shelf, deep and bottom waters — was found. For the first time, detailed information on the bottom topography of the ocean in the vicinity of this section made it possible to show the determining role of bottom topography features in the distribution of newly formed bottom water along the continental slope. The tendency of increasing of the volume of bottom water formed in the Prydz Bay in recent years is revealed, which is associated with the intensification of the basal melting of the ice shelf leading to an increase in the volume of the formation of supercooled Shelf Water, the most important component in the formation of bottom water.
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Solomon, Amy, e Matthew D. Shupe. "A Case Study of Airmass Transformation and Cloud Formation at Summit, Greenland". Journal of the Atmospheric Sciences 76, n.º 10 (19 de setembro de 2019): 3095–113. http://dx.doi.org/10.1175/jas-d-19-0056.1.
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Abstract This study investigates cloud formation and transitions in cloud types at Summit, Greenland, during 16–22 September 2010, when a warm, moist air mass was advected to Greenland from lower latitudes. During this period there was a sharp transition between high ice clouds and the formation of a lower stratocumulus deck at Summit. A regional mesoscale model is used to investigate the air masses that form these cloud systems. It is found that the high ice clouds form in originally warm, moist air masses that radiatively cool while being transported to Summit. A sensitivity study removing high ice clouds demonstrates that the primary impact of these clouds at Summit is to reduce cloud liquid water embedded within the ice cloud and water vapor in the boundary layer due to vapor deposition on snow. The mixed-phase stratocumulus clouds form at the base of cold, dry air masses advected from the northwest above 4 km. The net surface radiative fluxes during the stratocumulus period are at least 20 W m−2 larger than during the ice cloud period, indicating that, in seasons other than summer, cold, dry air masses advected to Summit above the boundary layer may radiatively warm the top of the Greenland Ice Sheet more effectively than warm, moist air masses advected from lower latitudes.
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Haines, Keith, e Chris Old. "Diagnosing Natural Variability of North Atlantic Water Masses in HadCM3". Journal of Climate 18, n.º 12 (15 de junho de 2005): 1925–41. http://dx.doi.org/10.1175/jcli3348.1.
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Abstract A study of thermally driven water mass transformations over 100 yr in the ocean component of the Third Hadley Centre Coupled Ocean–Atmosphere General Circulation Model (HadCM3) is presented. The processes of surface-forced transformations, subduction and mixing, both above and below the winter mixed layer base, are quantified. Subtropical Mode Waters are formed by surface heat fluxes and subducted at more or less the same rate. However, Labrador Seawater and Nordic Seawater classes (the other main subduction classes) are primarily formed by mixing within the mixed layer with very little formation directly from surface heat fluxes. The Subpolar Mode Water classes are dominated by net obduction of water back into the mixed layer from below. Subtropical Mode Water (18°C) variability shows a cycle of formation by surface fluxes, subduction ∼2 yr later, followed by mixing with warmer waters below the winter mixed layer base during the next 3 yr, and finally obduction back into the mixed layer at 21°C, ∼5 yr after the original formation. Surface transformation of Subpolar Mode Waters, ∼12°C, are led by surface transformations of warmer waters by up to 5 yr as water is transferred from the subtropical gyre. They are also led by obduction variability from below the mixed layer, by ∼2 yr. The variability of obduction in Subpolar Mode Waters also appears to be preceded, by 3–5 yr, by variability in subduction of Labrador Sea Waters at ∼6°C. This supports a mechanism in which southward-propagating Labrador seawater anomalies below the subpolar gyre can influence the upper water circulation and obduction into the mixed layer.
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Liu, Beibei, Michiel Lambrechts, Anders Johansen e Fan Liu. "Super-Earth masses sculpted by pebble isolation around stars of different masses". Astronomy & Astrophysics 632 (26 de novembro de 2019): A7. http://dx.doi.org/10.1051/0004-6361/201936309.
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We developed a pebble-driven core accretion model to study the formation and evolution of planets around stars in the stellar mass range of 0.08 M⊙–1 M⊙. By Monte Carlo sampling of the initial conditions, the growth and migration of a large number of individual protoplanetary embryos were simulated in a population synthesis manner. We tested two hypotheses for the birth locations of embryos: at the water ice line or log-uniformly distributed over entire protoplanetary disks. Two types of disks with different turbulent viscous parameters αt of 10−3 and 10−4 are also investigated to shed light on the role of outward migration of protoplanets. The forming planets are compared with the observed exoplanets in terms of mass, semimajor axis, metallicity, and water content. We find that gas giant planets are likely to form when the characteristic disk sizes are larger, the disk accretion rates are higher, the disks are more metal rich, and/or their stellar hosts are more massive. Our model shows that first, the characteristic mass of super-Earth is set by the pebble isolation mass. Super-Earth masses increase linearly with the mass of its stellar host, which corresponds to one Earth mass around a late M-dwarf star and 20 Earth masses around a solar-mass star. Second, the low-mass planets, up to 20 M⊕, can form around stars with a wide range of metallicities, while massive gas giant planets are preferred to grow around metal rich stars. Third, super-Earth planets that are mainly composed of silicates, with relatively low water fractions, can form from protoplanetary embryos at the water ice line in weakly turbulent disks where outward migration is suppressed. However, if the embryos are formed over a wide range of radial distances, the super-Earths would end up having a distinctive, bimodal composition in water mass. Altogether, our model succeeds in quantitatively reproducing several important observed properties of exoplanets and correlations with their stellar hosts.
Teses / dissertações sobre o assunto "Water masses formation"
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Barral, Quentin-Boris. "Caractérisation du front Nord-Baléares : Variabilité et rôle de la circulation des masses d'eau en Méditerranée Occidentale". Electronic Thesis or Diss., Toulon, 2022. http://www.theses.fr/2022TOUL0006.
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La Méditerranée Occidentale est l’un des bassins avec le plus de pollution plastique au monde, et son réchauffement de surface est quatre fois plus intense que celui des océans. Elle est dite "bassin laboratoire" pour l’étude de l’océan global : elle développe sa propre circulation de retournement. Sa courantologie est composée de 4 couches et d’environ 6 masses d’eau. La rencontre de deux masses d’eau de différentes températures et salinités en surface crée un front thermohalin. Cette thèse présente des avancées récentes sur la caractérisation des zones de fronts et sur la dynamique des masses d’eau en Méditerranée Occidentale. La détection de fronts de surface dans une simulation, et sur des observations satellites, a produit des cartes de statistiques de présence des fronts. Deux zones majeures de fronts, de température et de salinité, apparaissent dans le centre du bassin et se révèlent très différentes.La première est thermique, estivale et sur une profondeur de 50m. Elle part des Pyrénées mais s’estompe vers le nord-ouest de la Corse. La deuxième est haline, quasi-permanente et sur 200m de profondeur. Elle relie nettement les îles Baléares au sud-ouest de la Sardaigne. Précédemment confondues au sein d’un seul « front Nord-Baléares », leurs différentes origines et localisations impliquent que deux nouvelles appellations soient proposées. La zone de fronts halins marque la frontière entre eaux atlantiques jeunes du sud (AW) et vieilles du nord (mAW). Elle se fait déplacer vers le sud lors de la formation d’eau profonde (DWF) interannuelle du bassin provençal, et remonte ensuite vers le nord sous l’influence des tourbillons algériens (AEs). Le développement d’un algorithme de séparation des 6 différentes masses d’eau a permis de décrire la circulation particulière de chacune d’entre elles dans la simulation. Les circulations moyennes coïncident avec la littérature connue. Puis, outre un évènement irréaliste de circulation profonde, deux résultats importants sont déduits. D’une part, la simulation montre que la DWF du bassin provençal semble disloquer le gyre profond Est-Algérien, modifiant à son tour la trajectoire des AEs en surface. D’autre part, la DWF de 2005 a induit en 2009 un transit d’eau profonde vers la mer Tyrrhénienne.Néanmoins, ce transit a provoqué en surface un courant de retour de mAWs par le canal de Sardaigne vers le bassin algérien, au lieu d’un apport habituel par le canal Corse, et entraînant exceptionnellement de l’AW jusqu’en mer LigureThe Western Mediterranean is one of the basins with the most plastic pollution in the world, and its surface warming is four times more intense than that of the oceans. It is a so-called "laboratory basin" for the study of the global ocean : it develops its own overturning circulation. Its currentology is composed of 4 layers and about 6 water masses. The meeting of two water masses of different surface temperatures and salinities creates a thermohaline front. This thesis presents recent advances in the characterisation of front zones and water mass dynamics in the Western Mediterranean. The detection of surface fronts in a simulation, and on satellite observations, has produced maps of front presence statistics. Two major zones of fronts, of temperature and salinity, appear in the centre of the basin and are very different. The first is thermal, summer and 50m deep. It starts in the Pyrenees but fades towards the north-west of Corsica. The second is haline, quasi-permanent and over 200m depth. It clearly connects the Balearic Islands to southwestern Sardinia. Previously confused within a single "North Balearic front", their different origins and locations imply that two new designations are proposed. The haline front zone marks the boundary between young southern Atlantic waters (AW) and old northern waters (mAW). It is displaced southwards during the interannual deep water formation (DWF) of the Provençal basin, and then moves northwards under the influence of Algerian eddies (AEs). The development of an algorithmfor separating the 6 different water masses allowed the description of the particular circulation of each of them in the simulation. The average circulations coincide with the known literature. Then, besides an unrealistic deep circulation event, two important results are deduced. On the one hand, the simulation shows that the DWF of the Provençal Basin seems to dislocate the deep East Algerian gyre, modifying in turn the trajectory of the surface AEs. On the other hand, the 2005 DWF induced a deep water transit towards the Tyrrhenian Sea in 2009. However, this transit induced a surface return flow of mAWs through the Sardinia Channel towards the Algerian Basin, instead of the usual inflow through the Corsica Channel, and exceptionally causing AWto reach the Ligurian Sea
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Akhoudas, Camille. "Un nouveau regard sur la dynamique de l’océan Austral et ses interactions avec la cryosphère révélé par une approche isotopique". Electronic Thesis or Diss., Sorbonne université, 2020. http://www.theses.fr/2020SORUS464.
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L’océan Austral est un acteur central de la circulation océanique mondiale et du système climatique terrestre. Malgré l’essor des observations in situ dans cette région reculée du globe depuis les années 1990 (avec notamment le début de « l’ère satellitaire » et des grands programmes internationaux d’observations tel que WOCE, CLIVAR, GO-SHIP, ou ARGO), ce vaste océan reste encore aujourd’hui largement méconnu. Il est pourtant nécessaire de parvenir à mieux observer et comprendre les mécanismes de sa dynamique océanique ainsi que sa variabilité afin de prédire au mieux l’évolution future du système climatique. Notamment, une des particularités qui rend l’océan Austral essentiel dans le système climatique est qu’il est l’un des principaux lieux de ventilation de l’océan profond, qui permet une redistribution et un stockage de chaleur, d’eau douce, de carbone, d’oxygène, et de nutriments, entre autres. Cette ventilation est en partie dirigée par une circulation verticale unique connectant la surface aux abysses océaniques, mise en mouvement par les intenses interactions et échanges de flux d’énergie et de flottabilité entre atmosphère, océan et cryosphère. Je me penche dans cette thèse sur certains aspects de la dynamique australe en m’efforçant d’apporter une vue mécanistique de la circulation grande échelle et des changements en cours. Un fil rouge méthodologique que j’emploie sur l’ensemble de cette thèse est l’utilisation d’observations des isotopes stables de l’eau, traceur passif utilisé couramment dans un grand nombre de disciplines des sciences de la terre, mais jusque récemment assez peu en océanographie physique. La mesure des isotopes de l’eau constitue un outil, qui en tant que traceurs de l’origine de l’eau, permet de mieux caractériser les différentes composantes du cycle hydrologique ainsi que son évolution. En particulier, la composition isotopique de l’eau de mer représente une empreinte importante des masses d’eau, contenant des informations sur les conditions de leur formation et leur évolution. Dans cette thèse, au-delà du travail méthodologique important sur le terrain et en laboratoire pour l’échantillonnage, l’analyse et la calibration des mesures isotopiques, j’utilise les isotopes de l’eau en combinaison avec d’autres traceurs plus conventionnels pour aborder avec un nouveau regard, les questions du rôle des interactions entre océan et calotte polaire à la circulation grande échelle, de la signature des eaux de surface dans les abysses, ou encore de l’impact des changements de régimes atmosphériques ou de fonte de la cryosphère sur l’océan de surface. Au-delà de la seule utilisation des isotopes stables de l’eau, les approches que j’ai mises en place m’ont permis de documenter la quantité de fonte et de regel d’une des plus grandes cavités glaciaires au monde, qui influence les caractéristiques des masses d’eau denses, précurseurs des eaux abyssales se formant en mer de Weddell. Mes résultats mettent également à jour la proportion que représente, in fine, ces eaux denses dans la production des eaux abyssales dans le secteur Atlantique de l’océan Austral. Je détaille les processus qui mènent à la formation des eaux abyssales et avec cette nouvelle force, je montre que des estimations passées de la production d’eaux abyssales en apparente contradiction, s’attaquaient en réalité à différents processus. Finalement, je quantifie les changements des apports en eau douce lors des trois dernières décennies sur les tendances des propriétés de surface dans le secteur Indien de l’océan Austral. Mes résultats démontrent que des changements dans le régime des précipitations expliquent les changements des caractéristiques de l’océan surface affectant la stratification avec des conséquences sur la formation des masses d’eau et la circulation de retournement de l’océan Austral à grande échelleThe Southern Ocean is a key component in global ocean circulation and the Earth's climate system. Despite the increase of in situ observations in this remote region since the 1990s (notably with the « satellite era » and major international observation programs such as WOCE, CLIVAR, GO-SHIP, or ARGO), this immense ocean remains largely unknown. However, it is essential to observe and understand the mechanisms of its dynamics as well as its variability with the aim to predict the future evolution of the climate system. In particular, one important characteristic of the Southern Ocean is that it is one of the main sites of deep ocean ventilation, which allows redistribution and sequestration of heat, freshwater, carbon, oxygen, and nutrients. This ventilation process is mainly associated with a vertical circulation connecting the ocean surface to the abyss, fueled by intense interactions and exchanges of energy and buoyancy fluxes between atmosphere, ocean and cryosphere. In this thesis, I apprehend some aspects of the Southern Ocean dynamics by providing a mechanistic view of large-scale circulation and its ongoing changes. The approach I use throughout this thesis is based on observations of stable water isotopes, a passive tracer commonly used in a large number of earth science disciplines, but until recently only sparsely used in physical oceanography. Stable water isotopes constitute a robust tool which, as a tracer of the origin of water, help to better characterize the different components of the hydrological cycle as well as its evolution. In particular, the isotopic composition of seawater represents an important imprint of water masses, containing information on the conditions of their formation and their evolution. In this thesis, beyond the important methodological work at sea and in the laboratory for the sampling, analysis and calibration of isotopic measurements, I use the stable water isotopes in combination with other more conventional tracers to apprehend, with a new perspective, the questions of the role of interactions between the Southern Ocean and the Antarctic Ice Sheet in large-scale circulation, the signature of surface waters in the abyss, or even the impact of changes in atmospheric or cryosphere regimes on the surface ocean. Beyond the only use of stable water isotopes, original approaches have allowed me to document melting and refreezing of one of the largest ice shelves in the world, which influences the characteristics of the dense waters, precursors of abyssal waters produced in the Weddell Sea. My results also reveal the proportion of these dense waters in bottom water formation in the Atlantic sector of the Southern Ocean. We detail the processes that lead to the formation of bottom waters and with this new insight, we demonstrate that past estimates of bottom water production, in apparent contradiction, were actually focusing on different processes. Finally, I propose to quantify the changes in freshwater inputs over the past three decades that influence the trends in surface properties in the Indian sector of the Southern Ocean. The results demonstrate that changes in the precipitation regime explain changes in the surface ocean characteristics impacting stratification with consequences for large-scale water mass formation and overturning circulation in the Southern Ocean
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Jenness, Timothy. "A molecular line and continuum study of water maser sources". Thesis, University of Cambridge, 1996. https://www.repository.cam.ac.uk/handle/1810/245081.
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Recent observations at the James Clerk Maxwell Telescope (JCMT) and elsewhere have identified a class of very deeply embedded, possibly protostellar, sources which are not associated with any of the traditional indicators of star formation, such as HII regions and near-infrared emission, but which do lie close to otherwise isolated H2O masers. This thesis describes a search, based on catalogues of known water maser positions, for new deeply embedded cores similar to those found in S106 and M17. In addition to millimetre molecular line and submillimetre continuum observations, 22 GHz and 8 GHz radio observations have been made of a number of the sources in order to obtain more accurate maser positions and to search for any associated compact HII regions. Observing sources such as these in less active star forming regions provides a cleaner environment in which to examine the maser excitation and the ongoing process of star formation. A sample of 44 water maser sources was observed from which submillimetre continuum emission was detected from 40 (91 per cent). The most striking feature of the data is the close association of the masers with the submillimetre cores: the data are consistent with masers occurring within 6000 AU of the embedded core. The results can be summarised as follows: o High temperature gas has been detected, and most of the submillimetre cores have mean densities greater than 10^6 /cm^3. o The masers have low velocities with respect to the molecular cloud and are uniformly distributed within 6600 AU of the submillimetre core. o The isotropic maser luminosity is proportional to the far-infrared luminosity over more than 5 orders of magnitude. o There is no obvious correlation between the near-infrared spectral class and the maser emission. o Where a radio spectral index is known the majority of sources are optically thin HII regions. The bulk of the remainder are undetected and have a flux density less than 1 mJy. o Masers not associated directly with a submillimetre core show explicit evidence for shocks. Embedded cores \emph{have} been detected with this survey and the maser emission is consistent with collisionally excited pump models.
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Roveretto, Marie. "Formation et vieillissement des aérosols : impact de la photochimie hétérogène". Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1346.
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Les interfaces sont omniprésentes dans l'environnement et, de plus, de nombreux processus atmosphériques clés, comme les dépôts de gaz, la formation d'aérosol et de nuages, sont, à un stade ou à un autre, fortement touchés par les processus physiques et chimiques qui se produisent aux interfaces. Malheureusement, ces réactions hétérogènes ne sont pas entièrement comprises à ce jour et limitent notre capacité à simuler et quantifier l’impact des aérosols du fait de grandes incertitudes quant à leur formation et leur évolution dans la troposphère. Ce travail de thèse se propose donc d’améliorer nos connaissances sur les réactions photochimiques aux interfaces air/liquide afin d’obtenir une compréhension fondamentale des processus sous-jacents, ce qui pourrait être crucial pour l'évaluation de leurs impacts atmosphériques. Premièrement la réactivité de l’acide stéarique à l’interface air/eau sous irradiation a été étudiée dans différentes matrices grâce un outil très sensible, la balance de Langmuir. Nous avons observé la dégradation des monocouches d’acide stéarique sous irradiation et ce, même en l’absence de photosensibilisateur. Les expériences réalisées avec des monocouches dans différents états de surface indiquent que la pression de surface exerce une influence sur cette réactivité. Le couplage APCI-Orbitrap a été utilisé pour détecter et identifier des composés halogénés produits à partir d’une solution irradiée contenant un photosensibilisateur à savoir l’acide 4-benzoylbenzoïque. Les effets de l’octanol comme surfactant et de l’acide citrique comme donneur de protons sur ces réactions photosensibilisées ont également été examinés. De plus, la formation d’aérosols secondaires et leur vieillissement en milieu marin (au Cap-Vert) ont été étudiés sous différents aspects. Les expériences démontrent clairement l’existence de processus photosensibilisés à l’interface air/mer en tant que source d’aérosols secondaires marins. Pour finir, des travaux sur la photochimie de la matière organique issue de phytoplanctons ont permis de récolter des informations sur leur réactivité dans la phase liquide. Globalement, les résultats obtenus durant cette thèse montrent que la photochimie étudiée ici peut avoir une incidence importante sur la microcouche superficielle des océans et, par extension, sur les aérosols marinsInterfaces are ubiquitous in the environment, and in addition many key atmospheric processes, such as gas deposition, aerosol and cloud formation are, at one stage or the other, strongly affected by physical and chemical processes occurring at interfaces. Unfortunately, these heterogeneous reactions are not fully understood to date and limit our ability to simulate and quantify the impact of aerosols due to large uncertainties in their formation and their evolution in the troposphere. This thesis aims to improve our knowledge about photochemical reactions at the air/liquid interfaces, which could be crucial for the assessment of their atmospheric impacts. Firstly, the reactivity of stearic acid at the air/water interface under irradiation was studied in different matrices thanks to a very sensitive tool, the Langmuir trough. We observed that monolayers of stearic acid undergo degradation under irradiation, even in the absence of photosensitizers. Experiments with monolayers in different surface states indicate that surface pressure influences this reactivity. APCI-Orbitrap coupling was used to detect and identify halogenated compounds produced from an irradiated solution containing a photosensitizer, 4-benzoylbenzoic acid. The effects of octanol as a surfactant and citric acid as a proton donor on these photosensitized reactions were also examined. In addition, the formation of secondary aerosols and their aging in the marine environment (at Cape-Verde) were studied in different conditions. The experiments clearly demonstrate the existence of photosensitized processes at the air/sea interface as a source of marine secondary aerosols. Finally, work on the photochemistry of organic matter from phytoplanktons gave information on their reactivity in the liquid phase. Overall, the results obtained during this thesis show that the photochemistry studied here can have a significant impact on the superficial microlayer of the oceans and, by extension, on marine aerosols
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Boissier, Jean-Michel. "Etude des flux de matière organique transportée par les eaux de percolation de trois sols forestiers, à la suite de fortes précipitations orageuses simulées". Grenoble 1, 1992. http://www.theses.fr/1992GRE10112.
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Les milieux terrestres representent une source potentielle de matiere organique pour les ecosystemes aquatiques, notamment au cours de fortes precipitations orageuses. Dans ce travail, nous avons cherche a quantifier une partie des transferts entre les ecosystemes terrestres et les milieux aquatiques, en utilisant des descripteurs globaux tels que les differentes formes du carbone organique, l'activite enzymatique, les denombrements bacteriens, ainsi que des mesures physico-chimiques simples. Ces descripteurs ont ete mesures a la fois sur trois sols forestiers de montagne (deux sols bruns et un pseudogley podzolique) et sur les eaux de percolation qui s'en ecoulent a la suite de precipitations orageuses simulees. Pour les deux sols bruns, on observe de fortes variations de l'activite enzymatique edaphique. Ces variations sont fonction des evenements climatiques precedant les pluies artificielles. L'humidite des sols semble etre la seule variable pedoclimatique a jouer un role, a notre echelle de mesures. Cette influence est moins marquee pour le pseudogley podzolique, sans doute a cause de l'effet mulch induit par la litiere. Les caracteristiques biologiques des eaux de percolation sont inversement proportionnelles a celles mesurees sur leurs sols d'origines, notamment pour les deux sols bruns. Nous avons attribues les differentes valeurs de l'activite biologique des eaux de percolation a la qualite du carbone organique entraine par ces dernieres. Des mesures de biodegradabilite du carbone organique, faites a l'aide de bacteries autochtones, montrent que les sols bruns sont capables d'alimenter les milieux aquatiques en carbone assimilable. Le pseudogley podzolique relargue des eaux dont les charges en carbone sont majoritairement constituees de carbone refractaire a une biodegradation rapide (produits phenoliques)
Livros sobre o assunto "Water masses formation"
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Mauritzen, Cecilie. A study of the large scale circulation and water mass formation in the Nordic Seas and the Arctic Ocean. [Wood Hole, Mass: Woods Hole Oceanographic Institution, 1994.
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Kiszka, Krzysztof. Ruchy osuwiskowe w świetle badań dendrogeomorfologicznych na podstawie analizy osuwiska Sawickiego w Beskidzie Niskim = Landsilde movements based on dendrogeomorphological research based on a analysis of the Sawicki Landslide in the Beskid Niski mts. Instytut Geografii i Przestrzennego Zagospodarowania im. Stanisława Leszczyckiego, Polska Akademia Nauk, 2021. http://dx.doi.org/10.7163/9788361590835.
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Research concerns the problem of landslide movement, which is one of the most important geomorphological processes in the Carpathians. The aim of the studies is to determine the temporal and spatial complexity of landslide activity and to demonstrate the suitability of using different species of conifers in the dendrogeomorphological method. The Sawicki landslide located in Beskid Niski Mts., which is one of the largest landslides in the Polish Flysch Carpathians, was selected for dendrogeomorphological analysis. The dendrogeomorphological method and geomorphological mapping were used in the research. 1078 samples from conifers (fir, spruce, larch and pine) growing on the Sawicki landslide and its immediate surroundings were taken using an increment borer in 2013- 2018. The cores were taken from the upslope and downslope side of the tree stump. The width of annual tree rings were measured for each extracted core sample. The landslide activity was assessed on the basis of the eccentricity, the eccentricity index and its yearly variation. Geological and topographic maps, published data on landslides activity in the research area, precipitation data from the Research Station in Szymbark (Institute of Geography and Spatial Organization Polish Academy of Science) for 1968-2017 and from the meteorological station in Krynica (Institute of Meteorology and Water Management) for 1881-2010 were also used for dendrogeomorphological research of Sawicki landslide. The research shows that the Sawicki landslide is characterized by varied temporal and spatial complexity of landslide activity. The dynamics of displacements within the research sites and research sub-sites, including various fragments of landslides, and movements of colluvial packages is spatially mosaic and chaotic in time. Mass movements covering almost the entire surface of the landslide occurred in the years 1913-1914 and 1974-1975, while in the years 1888, 1906-1907, 1916, 1918, 1929, 1965, 1973, 1980, 1983-1985, 1997 landslide activity was recorded only in its particular parts. The largest variation in the dynamics of landslide movements is characteristic for the period 1970-1985. It was also found that in the initial stage of formation of the landslide tongue, the colluviums movement is disordered. During further downhill movement, the direction of displacement is arranged. Periods of Sawicki landslide activity refers to extremely humid years (62%) and wet years (48%) and they are consistent with the years of landslides activity in Szymbark, listed in the current literature of the subject. The most predisposed conifer species to dendrogeomorphological analysis were spruce, larch and fir. Despite its limitations, the dendrogeomorphological method is a useful tool in landslide activity research.
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N-Force Presents: Tips Force. Shropshire, UK: Europress Impact Ltd., 1992.
Encontre o texto completo da fonteCapítulos de livros sobre o assunto "Water masses formation"
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Gratchev, Ivan, Sinnappoo Ravindran, Dong Hyun Kim, Chen Cui e Qianhao Tang. "Mechanisms of Shallow Rainfall-Induced Landslides from Australia: Insights into Field and Laboratory Investigations". In Progress in Landslide Research and Technology, Volume 1 Issue 1, 2022, 113–22. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-16898-7_7.
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AbstractThis paper presents and discusses the mechanisms of rainfall-induced shallow landslides that commonly occur in South East Queensland (SEQ) and northern New South Wales (NSW), Australia. The major factors causing the formation of landslide mass such as geology, weathering, and rainfall patterns were discussed. Results from field surveys and laboratory testing of rock/soil material from landslide masses were presented, and relationships between the material strength and landslide occurrence were drawn. It was found that most of shallow slides were related to sandstone deposits. Those failures occurred on natural slopes and road cuts with the inclination of the failure plane being in the range of 35–45°. For natural slopes where the landslide mass mostly consisted of coarse-grained soil, the relationship between the soil strength and water content was established. In addition, the relationship between rainfall patterns such as intensity and duration, and the landslide occurrence was presented. Based on the data from field work and laboratory results including a series of flume tests, the mechanism of shallow landslides triggered by rainfall events was identified and discussed.
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Testi, L., M. Felli, P. Persia e M. Roth. "Near infrared images of galactic water masers". In Star Formation and Techniques in Infrared and mm-Wave Astronomy, 312–13. Berlin, Heidelberg: Springer Berlin Heidelberg, 1994. http://dx.doi.org/10.1007/3-540-58196-0_57.
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"Formation and descent of water masses". In The Oceanic Thermohaline Circulation: An Introduction, 121–51. New York, NY: Springer New York, 2007. http://dx.doi.org/10.1007/978-0-387-48039-8_7.
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Samah, Ourras, El Aymani Ismail, Mouden Najoua, El Gabardi Soumaya, Adnani Manal, Selmaoui Karima, Artib Mariam et al. "Saffron endomycorrhizae: diversity and effect on plant growth and corm formation". In Mycorrhiza - New Insights [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.106881.
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Saffron cultivation is an important alternative for marginalized areas. Due to low soil fertility and low water availability, arbuscular mycorrhizal fungi are an essential alternative for maintaining fertility and water economy, stimulating growth and protecting plants against soil diseases. Studies on the diversity of endomycorrhizal fungi in the rhizosphere of Crocus sativus in Taliouine (Tinfat), located in Morocco, revealed the impact of age saffron plantations. A greater endomycorrhizal fungi density was recorded in the rhizosphere of saffron plants from plots operated for 2 years (138.66/100 g of soil) over that occupied for 10 years. Seventeen morphotypes of collected spores belong to 5 genera: Glomus (seven species), Acaulospora (seven species), Rhizophagus, Densicitata, and Funneliformis (one species). The weak endomycorrhizal species richness can be explained by the accumulation of C. sativus residues over time and its allelopathic effect. The beneficial effect of composite endomycorrhizal inocula, originating from Moroccan saffron plantations, was obvious in the growth of saffron plants, mother bulb number, the leaves length, root, and vegetative masses. These inocula mycorrhized over time saffron plants’ roots and can sporulate at the level of the rhizosphere of these plants. The use of composite inocula, as biofertilizers, can be one of the solutions for sustainable agriculture.
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Wright, James D. "Role of the Greenland-Scotland Ridge in Neogene Climate Changes". In Tectonic Boundary Conditions for Climate Reconstructions, 192–211. Oxford University PressNew York, NY, 1998. http://dx.doi.org/10.1093/oso/9780195112450.003.0009.
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Abstract Cenozoic climates are marked by long-term cooling since the early Eocene that evolved into the large amplitude glacial/interglacial cycles of the late Pleistocene. Circulation models (both atmospheric and oceanic) have simulated these changes by altering the concentration of atmospheric trace gases (i.e., increased CO2) or by changing the meridional heat transports (increased delivery of heat to the poles via oceanic circulation) (e.g., Barron, 1983, 1987; Manabe and Bryan, 1985; Rind, 1987; Covey and Barron, 1988; Covey and Thompson, 1989; Manabe et al., 1990; Rind and Chandler, 1991). There is evidence in support of both mechanisms, leaving unclear the fundamental cause of the long-term climate change during the Cenozoic. Identifying mechanisms that triggered Cenozoic cooling has focused on tectonic changes, both marine and terrestrial, that fundamentally altered the ocean-atmosphere system. Arrangements of continents and marine gateways dictate surface and deep-water circulation patterns, and therefore, how water masses communicate between the ocean basins. Opening of the Drake Passage and uplift of the Central American Isthmus are two gateways that are often associated with climate change. The Drake Passage gateway is thought to be a critical “valve” in the development of a circumpolar circulation that led to the thermal isolation of Antarctica (Kennett, 1977). The closure of the Central American Isthmus has been implicated as a potential causes for largescale Northern Hemisphere glaciation (Keigwin, 1982) and the formation of deepwater in the North Atlantic (Keigwin, 1982; Maier-Reimer et al., 1990).
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"of control. The state of Queensland has generous expertise in this area, with the CSIRO Division of Entomology – Lands Department group in Brisbane boasting spectacular success against Salvinia and Eichhornia, and near the reservoir at James Cook University a USDA unit was involved in successes with the Tennessee Valley Authority (TVA) (see Chapter 12) using a range of stem-boring and leaf-mining insects (Balciunas et al. 1993). One might consider the herbivorous grass carp Ctenopharyngodon idella, originally from China, more as a harvester than a biological control agent. This fish grazes on submerged weeds such as Hydrilla, Myriophyllum, Chara, Potamogeton and Ceratophyllum, and at stocking rates of 75 fish/ha control is rapidly achieved. Some introductions in the USA have resulted in removal of all vegetation (Leslie et al. 1987), and in the Australian context the use of sterile (triploid) fish (Cassani and Canton 1985) could be the only consideration. However, in view of the damage already done by grass carp to some inland waterways in Australia, it is suspected that this option would be greeted with horror. Mechanical control involves the physical removal of weeds from a problem area and is useful in situations where the use of herbicides is not practical or poses risks to human health or the environment. Mobile harvesters sever, lift and carry plants to the shore. Most are intended for harvesting submerged plants, though some have been designed or adapted to harvest floating plants. Handling the harvested weed is a problem because of their enormous water content, therefore choppers are often incorporated into harvesting machinery design. However, many mechanical harvesters have a small capacity and the process of disposing of harvested plant material is time-consuming. Any material that remains may affect water quality during the decay process by depleting the water of oxygen. Furthermore, nutrients released by decay may cause algal blooms (Mitchell 1978). Another disadvantage of mechanical removal is that disturbance often promotes rapid new growth and germination of seed, and encourages the spread of weed by fragmentation. Some direct uses of macrophytes include the following: livestock food; protein extraction; manufacture of yeast; production of alcohol and other by-products; the formation of composts, mulches and fertilizers; and use for methane generation (Williams 1977). Herbicides either kill on contact, or after translocation through the plant. Some are residual and retain their toxicity for a period of time. Where herbicides are used for control of plants, some contamination of the water is inevitable (Bill 1977). The degree of contamination depends on the toxicity of the material, its fate and persistence in the water, the concentration used and the main purpose served by the water. After chemical defoliation of aquatic vegetation, the masses of decaying organic debris produced can interfere with fish production. Several factors must be taken into account when selecting and adapting herbicides for aquatic purposes, including: type of water use; toxicity of the herbicide to humans, fish, stock, and wildlife; rate of disappearance of residues, species affected and duration of control; concentration of herbicide; and cost (Bill 1977). The TVA has successfully used EPA-approved herbicides such as Endothall, Diquat, Fluridone and Komeen against Hydrilla (Burns et al. 1992), and a list of approved". In Water Resources, 153–54. CRC Press, 1998. http://dx.doi.org/10.4324/9780203027851-40.
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Lolaev, Alan, Aleksan Oganesyan, Aleksandr Badoev e Emil Oganesyan. "Determination of Water-Saturated Tailings Compaction Characteristics During Geotechnical Massif Formation". In Advances in Transdisciplinary Engineering. IOS Press, 2022. http://dx.doi.org/10.3233/atde220846.
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The research focuses on the tailing dump, which is located in the Norilsk industrial region’s (Northern Siberia) territory. The difficulty of precisely calculating the period of tailings consolidation presented itself to the authors while they conducted research on improving the technological parameters of the tailings alluvium. Without resolving this issue, it is impossible to improve the technology of the tailings alluvium. In order to assure safety and efficiency at all phases of construction and to strengthen the stability of the examined tailings, a sophisticated set of model tests and calculations was conducted. This work provided the foundation for modifying the work techniques. The method for defining the maximum density at the optimum humidity, when the formation of a geotechnical massif at the tailing dam’s inwash occurs, has been devised on the basis of laboratory testing. The findings from study may be effectively used as the foundation for building tailing dams.
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V. Kireicheva, Liudmila, Valery M. Yashin, Ekaterina А. Lentyaeva e Aleksey D. Timoshkin. "Diffuse Runoff from Agricultural Lands within a River Basin and Water Protection Measures". In Water Conservation - Inevitable Strategy [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.100439.
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This paper is dedicated to the study of the pollutants coming from agricultural lands located within the catchment into the Yakhroma river, a third-order tributary of the Upper Volga. The area of the river catchment is 1437 km2. It is located in the north-eastern part of the Moscow region, which geographically belongs to the Klinsko-Dmitrov ridge (the upper part of the basin) and the Upper Volga Lowland. The slopes and floodplain included in the reclaimed lands (more than 9 th ha) are lined with cities, rural settlements, numerous kitchen gardens, and agricultural lands. Water quality, river profile from the source to the mouth, and sources of pollution within the reclaimed lands of the Yakhroma floodplain were studied from 2004 to the present. A geospatial intelligence system (GIS) was developed for the catchment area. Land areas are allocated according to the conditions of surface runoff formation, taking into account soil types and slopes. The studies of the river water quality, tributaries, and drainage network in the reclaimed lands showed biogenic pollution caused by insufficiently treated wastewater discharged from cities and agricultural land, especially within the reclaimed massif. The calculations of the removal of nitrogen, phosphorus, and potassium from surface and drainage waters revealed that the main role in the pollution of both surface and drainage waters is played by nitrogen and potassium compounds, and to a lesser extent by phosphorus compounds. For nitrogen, removal from surface runoff was 27.36 t/year; for phosphorus it was 6.06 t/year; for potassium it was 242.28 t/year; with drainage runoff, the removal of nitrogen was 98.88 t/year; the removal of phosphorus was 0.38 t/year; the removal of potassium was 37.04 t/year. To reduce the inflow of surface diffuse runoff and to purify collector and drainage waters from nitrogen and phosphorus compounds, including the creation of bioplateaus and biosorption structures, it was proposed to use a set of protective measures, which will significantly reduce the biogenic load on the river flow.
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Carvalho, Ângelo Rodrigues de. "Countryside education and professional education: Territorialities under construction for a human formation". In PATHWAYS TO KNOWLEDGE: EXPLORING THE HORIZONS OF EDUCATION. Seven Editora, 2023. http://dx.doi.org/10.56238/ptoketheeducati-036.
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The present work brings the approach of the perspective of the construction of professional education from the Education of the Field, based on an educational thinking that is based on a formation of the subjects through human emancipation; reflecting the historicity of the Education of the Field thought by (their) Social Movements. The theoretical framework is based on the efforts of authors such as Bernardo Mançano Fernandes, Saskia Sassen, Doreen Massey, Mônica Molina and Pistrak. The methodology used was through semi-structured interviews with representatives of social movements that are in the locus of the research. Our reflection is based on the projects developed in the spaces of experiences of students, which are based on the Movement for a Rural Education, since it is contrary to the logic and dynamics of capitalist reproduction, which understands the field as a space of possibilities, valuing the cultural history of the subjects belonging to the territories of the field, of waters and forests. In this sense, Rural Education is an alternative to Rural Professional Education, especially with regard to the construction of territorialities that promote the integration of the subjects of the field, the waters and the forests.
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LOUCKS, ROBERT G., CHARLES KERANS, XAVIER JANSON e M. ALFREDO MARHX ROJANO. "Lithofacies Analysis and Stratigraphic Architecture of a Deep-Water Carbonate Debris Apron: Lower Cretaceous (Latest Aptian to Latest Albian) Tamabra Formation, Poza Rica Field Area, Mexico". In Mass-Transport Deposits in Deepwater Settings, 367–89. SEPM (Society for Sedimentary Geology), 2011. http://dx.doi.org/10.2110/sepmsp.096.367.
Texto completo da fonteTrabalhos de conferências sobre o assunto "Water masses formation"
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Яшин, Валерий Михайлович. "ECOLOGICAL APPROACH TO THE CONSIDERATION OF THE PROTECTIVE FUNCTIONS OF THE UNSATURATED ZONE". In Сборник избранных статей по материалам научных конференций ГНИИ "Нацразвитие" (Санкт-Петербург, Февраль 2021). Crossref, 2021. http://dx.doi.org/10.37539/feb295.2021.46.83.006.
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В статье на основе анализа формирования потоков влаги в ландшафтах предлагается рассматривать зону аэрации как природный объект - экологический демпфер. Экологические демпферы- это природные или антропогенно-природные образования, имеющие дополнительное сопротивление потоку и высокое значение ассимиляционной емкости, позволяющие сглаживать (гасить) результаты интенсивных изменений процессов переноса водных или воздушных масс, происходящих на границе объекта. Показаны границы зоны аэрации и формирование водного режима. In the article, based on the analysis of the formation of moisture flows in landscapes, it is proposed to consider the aeration zone as a natural object - an ecological damper. Environmental dampers are natural or anthropogenic-natural formations that have additional resistance to flow and a high value of assimilation capacity, which make it possible to smooth out (damp) the results of intensive changes in the processes of transfer of water or air masses occurring at the boundary of the object. The boundaries of the aeration zone and the formation of the water regime are shown.
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Almajid, Muhammad Majid, Markus Zechner e Zuhair A. AlYousif. "CO2 Sequestration: Sensitivity Analysis of Storage Mass to Multiphase Parameters". In Middle East Oil, Gas and Geosciences Show. SPE, 2023. http://dx.doi.org/10.2118/213959-ms.
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Abstract Geological CO2 sequestration is one of the main enablers for reducing carbon emissions. Prediction of CO2 behavior in uncertain subterranean formations requires more robust descriptions of the most critical geological and multiphase parameters. The objective of this work is to present a sensitivity analysis of multiphase parameters on the amount of CO2 stored/leaked in a sequestration project and to identify the most critical parameters that we need to focus on to ensure successful project implementation. A vertical equilibrium model is used to simulate the sequestration process for over 1000 years in the Johansen formation, which is a candidate site for large-scale CO2 storage offshore the southwest coast of Norway. The multiphase parameters of the capillary pressure and the relative permeability curves are altered randomly (Monte Carlo experiment). A distance-based generalized sensitivity analysis (DGSA) is used to interpret the responses and quantify the most influential parameters on five different masses of CO2 (free plume, leaked, residual after water reimbibition, residual CO2, trapped residually in structural traps). Amongst the five different masses of CO2 investigated in this work, the most influencing parameters were the residual CO2 saturation and the relative permeability exponent. The residual water saturation, capillary pressure curve exponent, and the entry pressure had much lesser effect on the computed masses of CO2. The mass of CO2 in the free plume as well as the mass of residual CO2 in the plume after water reimbibition were most sensitive to the residual CO2 saturation. On the other hand, the mass of CO2 leaked from the aquifer, the mass of residual CO2, and the mass of CO2 that is trapped residually in the structural traps were most sensitive to the relative permeability exponent. The results of our work indicate that initial experimental investigation in a sequestration project should be directed towards limiting the uncertainty of the relative permeability parameters such as the residual CO2 saturation and the relative permeability exponent.
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Busarev, V. V. "Active asteroids of the Main Belt as probable relics of the formation processes of giant planets". In ASTRONOMY AT THE EPOCH OF MULTIMESSENGER STUDIES. Proceedings of the VAK-2021 conference, Aug 23–28, 2021. Crossref, 2022. http://dx.doi.org/10.51194/vak2021.2022.1.1.076.
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The discovery and study of cometary activity of some bodies in the Main-Belt of asteroids (MBA) over the past decadeallowed us suggest that the most common cause of this phenomenon is a significant content of water ice in the subsurfacelayers of primitive asteroids. Accordingly, this may be a sign of the formation of such asteroids (or their parent bodies)behind the snowline. As demonstrated analytical calculations performed more than 50 years ago [1], a sharp increase inthe number and total mass of stone-ice bodies behind the snowline let possible the runaway growth of giant planets there,especially Jupiter. As follows from predominately hydrogen content of Jupiter’s atmosphere, its core probably formed overa few first million years due to the accretion of smaller bodies. However, should keep in mind that this process graduallychanged into its opposite. When the core of a giant planet is reaching several masses of the Earth, the capture and absorptionby it of smaller bodies is replacing by their gravitational ejection far beyond the zone of formation. Thus, all giant planetsmight have alternately turned (starting with Jupiter and ending with the most distant Neptune in accordance with thechronology of their formation) into “transporters” of small bodies of rock-ice composition from their zones of formation toother regions of the early Solar System including the MBA, where they now could be observed as active asteroids.
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Musunuri, Naga, Ian Fischer, Pushpendra Singh, Daniel E. Bunker e Susan Pell. "Fluid Dynamics of Hydrophilous Pollination in Ruppia (Widgeon Grass)". In ASME 2016 Fluids Engineering Division Summer Meeting collocated with the ASME 2016 Heat Transfer Summer Conference and the ASME 2016 14th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/fedsm2016-7891.
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The aim of this work is to understand the physics underlying the mechanisms of two-dimensional aquatic pollen dispersal, known as hydrophily, that have evolved in several genera of aquatic plants, including Halodule, Halophila, Lepilaena, and Ruppia. We selected Ruppia maritima, which is native to salt and brackish waters circumglobally, for this study. We observed two mechanisms by which the pollen released from male inflorescences of Ruppia is adsorbed on a water surface: 1) inflorescences rise above the water surface and after they mature their pollen mass falls onto the surface as clumps and disperses as it comes in contact with the surface; 2) inflorescences remain below the surface and produce air bubbles which carry pollen mass to the surface where it disperses. In both cases dispersed pollen masses combined with others under the action of lateral capillary forces to form pollen rafts. The formation of porous pollen rafts increases the probability of pollination since the attractive capillary force on a pollen raft toward a stigma is much larger than on a single pollen grain. The presence of a trace amount of surfactant can disrupt the pollination process as the pollen is not captured or transported on the water surface.
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Ahmed, R., D. Hsu, C. Bailey e T. B. Jones. "Dispensing Picoliter Droplets Using DEP Micro-Actuation". In ASME 2003 1st International Conference on Microchannels and Minichannels. ASMEDC, 2003. http://dx.doi.org/10.1115/icmm2003-1110.
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Non-uniform, AC electric fields created by coplanar electrodes patterned on a substrate are used to move and manipulate aqueous liquid masses, and to dispense very small droplets. This liquid dielectrophoretic microactuation scheme has potential applications for microfluidic systems in the laboratory on a chip. Simple, co-planar electrode strips are used to divide microliter-sized, sessile water droplets into large numbers of droplets down to ∼40 picoliters. The dispensing system uses the electrodes to draw a long finger or rivulet of liquid from the parent microliter droplet. When the voltage is removed, the rivulet breaks up into numbers of droplets as a result of the familiar capillary instability. We propose and provide data that supports a very simple power law dependence of the finger length upon time: Z(t)∝t, which governs the time required to fill a structure. A capillary instability, very similar to the case of the cylindrical jet, leads to droplet formation when voltage is removed. The hydrodynamic instability features a critical wavelength, below which instability is not possible, and a most unstable wavelength, which controls the volume and spacing of the droplets formed.
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Mendoza-Torres, J. E., e E. E. Lekht. "Time variations of water vapor masers in star-forming regions". In The seventh astrophysical conference: Star formation, near and far. AIP, 1997. http://dx.doi.org/10.1063/1.52744.
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Al-Marri, Saad Zayed, Gary Peach e Hernan Vigil Fernandez. "TBM Challenges on Musaimeer outfall tunnel". In The 2nd International Conference on Civil Infrastructure and Construction. Qatar University Press, 2023. http://dx.doi.org/10.29117/cic.2023.0017.
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Musaimeer outfall tunnel is the longest outfall tunnel in the Middle East. The tunnel was excavated by Earth Pressure Balance (EPB), Tunnel Boring Machine (TBM) and encountered three distinct rock masses namely Rus Formation, Midra-Shale, and Simsima Limestone along with water inflows at high pressure, complex mixed ground, and weaker ground strata prone to cavities with the presence of vertical and lateral fractures connected to the seabed. These conditions resulted in the TBM operating in very dry conditions where the addition of soil conditioners and water sprayed in the excavations chamber and cutter head were required to avoid clogging situations and create a pasty excavation material, which impacted TBM operation. The opposite scenario occurred when the TBM encountered very wet conditions while passing through weathered Simsima Limestone fully connected hydrostatically with the seabed. Such situations directly impacted the productions rates, quantities of consumables, extra cost on the tunnel enabling activities and finally, the need of both atmospheric and hyperbaric interventions into the cutter head up to 3.5 bar to replace cutting tools. Long tunnels with only one access shaft pose many programme problems for logistics, combine these with the requirement to drive directly out under the seabed for 10.2 km, and the programme issues become even more challenging. To meet and eventually improve on the planned completion date required a complex and extensive management of all tunnel logistics activities required to support consistent tunnelling for a two-year period. This technical paper will discuss the management issues and solutions implemented to meet the challenges of the outfall tunnel construction.
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Kairanbayeva, A., Zh Zhantayev, G. Nurpeissova, D. Panyukova e A. Kiyalbayev. "LANDSLIDE PROCESSES� IMPACT ON AUTOMOBILE ROAD CHARACTERISTICS". In 22nd SGEM International Multidisciplinary Scientific GeoConference 2022. STEF92 Technology, 2022. http://dx.doi.org/10.5593/sgem2022/2.1/s09.30.
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The research is part of the �Design of an intelligent system to forecast landslides' processes and their influence on the roads' technical and operational characteristics� project financed by the Ministry of Education and Science of the Republic of Kazakhstan by AP09260066 program. The research goal is in surveying deformed parts of �Almaty-Cosmostation� automobile road nearby critical slopes to identify in the next phases the causes of pavement degradation and formulate then the recommendation to prevent such degeneration. This site was chosen due to the extreme danger associated with the possible closure of the river flowing through the gorges along the road under study due to a landslide slope. This can lead to a change in the riverbed, the formation of a strong water flow, which will create a danger to the population, will lead to significant material damage. Main results. Within the framework of this project, new knowledge will be gained in the theory of forecasting the occurrence of landslide processes and their impact on the technical and economic indicators of highways, which undoubtedly has applied significance and contributes to the widespread introduction of intelligent systems for forecasting and making industry decisions. Detailed engineering and geological research of deformed parts of �Almaty-Cosmostation� automobile road nearby critical slopes are provided. The article results with the field researches to formulate causes of deterioration of the road pavement and formation of longitudinal and transversal cracks on it. To develop intelligent models for predicting landslide processes and their impact on the state of the road, the following types of work were carried out: georadar sounding method; Earth remote sensing methods; ground-satellite geodesy method; modeling and training of intelligent systems. Conclusions: The surface smoothness of the road pavement is partly below the minimum permissible level. The causes of the �irregular� (unusual) transversal cracks should be associated with slides of the rock masses and water falling from the rock slopes. Suggested causes of the grading�s slide slopes� erosion are the faint provision of surface drainage for the road pavement. The unevenness of the pavement on a micro level is connected to the uncompacted enough asphaltic concrete pavement and other pavement�s layers. The field researches� results will be used for training and testing of intellectual models.
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Guan, Lijun, Xiannan Wang, Jian Wang, Gao Bei, Adriaan Gisolf, Zhaoya Fan, Ashers Partouche et al. "Intelligent Wireline Formation Tester Evaluation of Low-Permeability and Low-Resistivity-Contrast Formation with Detailed Digital Planning." In Gas & Oil Technology Showcase and Conference. SPE, 2023. http://dx.doi.org/10.2118/214252-ms.
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Abstract Exploration and development drilling in offshore China is extending to Paleogene formations that are characterized by low-resistivity-contrast and low-permeability rocks. These formations have become a focus for increasing reserves and production. During exploration activities, these low-resistivity, low-formation-contrast formations have been critical and challenging for formation evaluation because the geological structure and lithology are more complex than in previously discovered fields. Differentiating hydrocarbon from water using petrophysical interpretation has a large uncertainty in these formations. Confirming the fluid type using conventional formation testing technology has been extremely challenging because the produced fluid is mainly mud filtrate, which is of no use for fluid confirmation. The dual-flowline architecture of the intelligent formation testing platform (IFT) is designed to systematically address shortcomings of legacy technology, enabling focused sampling in the tightest conventional formations. Specialized digital planning of the numerical flow models by adding a brine tracking facility and enumeration initialization was performed to (a) compare and benchmark the cleanup performance of conventional radial 3D probe and new focus radial probe; (b) simulate multiple scenarios including hydrocarbon-water transition to understand the salinity changes while pumping in various water saturation circumstance and optimize operational planning by quantifying cleanup time uncertainties even in two-phase fluid reservoir; and (c) history match the sampling drawdown, flow rate, and salinity change with actual sampling data and provide real-time answers to help accelerate the decision-making cycle. This dedicated design resulted in increased efficiency in water sampling compared to previous testing done by the operator. Whereas previous gas-water transition zone sampling was challenging because high water-based mud filtrate fractions masked the presence of formation water and formation hydrocarbon, the focused radial probe, combined with state-of-the-art resistivity measurements and prejob modeling of salinity change, allowed identification of gas and the measurement of formation water resistivity in a multiphase flow environment. The formation testing of these low-resistivity-contrast and low-permeability formations enabled acquisition of a 2% contaminated formation water sample in 140 minutes with formation mobility of 1 md/cP. The gas-water zone was confirmed from a dual-flowline resistivity measurement and a hydrocarbon show in mobility of 1.4 md/cP. The intelligent wireline formation testing platform enabled high-performance and efficient collection and identification of formation water and gas in a low-mobility low-resistivity-low-contrast formation.
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Chudnenko, K. V., V. V. Murzin e G. A. Pal'yanova. "PHYSICOCHEMICAL MODELING OF THE FORMATION OF GOLD-BEARING MAGNETITE-CHLORITE-CARBONATE ROCKS (KARABASH MASSIF, SOUTH URALS)". In The Geological Evolution of the Water-Rock Interaction. Buryat Scientific Center of SB RAS Press, 2018. http://dx.doi.org/10.31554/978-5-7925-0536-0-2018-84-86.
Texto completo da fonteRelatórios de organizações sobre o assunto "Water masses formation"
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Ramsey, Andree L., Heather H. Furey e Amy S. Bower. Overturning of the Subpolar North Atlantic Program (OSNAP): RAFOS Float Data Report June 2014 - January 2019. Woods Hole Oceanographic Institution, dezembro de 2022. http://dx.doi.org/10.1575/1912/29540.
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The Overturning in the Subpolar North Atlantic Program (OSNAP) is an international effort started in 2014 dedicated to achieving a better understanding of the link between dense-water formation and the meridional overturning circulation in the high-latitude North Atlantic. Moorings, gliders, and subsurface acoustically-tracked RAFOS floats have been used to collect temperature, salinity, and current data across the Labrador Sea, Irminger Sea, Reykjanes Ridge, Iceland Basin, Rockall-Hatton Plateau, and Rockall Trough. The specific objective of the OSNAP float program is to gather information on the pathways of the dense overflow waters transported by the deep limb of the overturning circulation and assess the connection of those pathways with currents observed crossing the OSNAP mooring line. This data report details the observations collected by 148 floats that were deployed for OSNAP during the summers of 2014, 2015, 2016 and 2017. Deployment locations were in the Iceland Basin, Irminger Sea, and in the Charlie-Gibbs Fracture Zone. Mission lengths ranged from 540-730 days, and the floats were ballasted to passively drift at a fixed pressure of either 1800, 2000, 2200, 2500, or 2800 dbar to tag the deep overflow water masses of the subpolar North Atlantic (Iceland-Scotland and Denmark Strait Overflow Waters).
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Mikula, R. J., I. S. Parsons, V. A. Munoz, W. W. Lam, C. Payette e K. C. McAuley. High-temperature settling of bitumen from Aostra's underground test facility. Natural Resources Canada/CMSS/Information Management, 1990. http://dx.doi.org/10.4095/331489.
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Several bitumen samples from AOSTRA's Underground Test Facility were obtained (heat exchanger outlet) in order to characterize the emulsion droplet size distribution and to ultimately establish whether or not high temperature settling could successfully be used to separate the bitumen and water phases. Characterization of the dispersed phase was not straightforward since the samples varied. The samples would sometimes be separated into a large bitumen mass and significant free water and sometimes be quite fluid with dispersed bitumen. It was our opinion that sampling contamination, perhaps with residual soaps, lead to some samples remaining as a bitumen in water emulsion without separating. Normally, one would expect that the bitumen would separate from the free water. Preliminary characterization of the solids in the feed was also done since it is known that mineral/solids composition can influence emulsion formation and the stability of rag layers in bitumen/water separation schemes. High temperature settling evaluations proved the feasibility of this type of settling as a method of bitumen separation producing a product of less than 5% water. Good results were achieved with temperatures from 190 to 220 °C and 250 to 1000 ppm demulsifier. Separation without demulsifiers vas not successful. Product samples were examined microscopically to determine the dispersed water size distributions.
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Lacerda Silva, P., G. R. Chalmers, A. M. M. Bustin e R. M. Bustin. Gas geochemistry and the origins of H2S in the Montney Formation. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/329794.
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The geology of the Montney Formation and the geochemistry of its produced fluids, including nonhydrocarbon gases such as hydrogen sulfide were investigated for both Alberta and BC play areas. Key parameters for understanding a complex petroleum system like the Montney play include changes in thickness, depth of burial, mass balance calculations, timing and magnitudes of paleotemperature exposure, as well as kerogen concentration and types to determine the distribution of hydrocarbon composition, H2S concentrations and CO2 concentrations. Results show that there is first-, second- and third- order variations in the maturation patterns that impact the hydrocarbon composition. Isomer ratio calculations for butane and propane, in combination with excess methane estimation from produced fluids, are powerful tools to highlight effects of migration in the hydrocarbon distribution. The present-day distribution of hydrocarbons is a result of fluid mixing between hydrocarbons generated in-situ with shorter-chained hydrocarbons (i.e., methane) migrated from deeper, more mature areas proximal to the deformation front, along structural elements like the Fort St. John Graben, as well as through areas of lithology with higher permeability. The BC Montney play appears to have hydrocarbon composition that reflects a larger contribution from in-situ generation, while the Montney play in Alberta has a higher proportion of its hydrocarbon volumes from migrated hydrocarbons. Hydrogen sulphide is observed to be laterally discontinuous and found in discrete zones or pockets. The locations of higher concentrations of hydrogen sulphide do not align with the sulphate-rich facies of the Charlie Lake Formation but can be seen to underlie areas of higher sulphate ion concentrations in the formation water. There is some alignment between CO2 and H2S, particularly south of Dawson Creek; however, the cross-plot of CO2 and H2S illustrates some deviation away from any correlation and there must be other processes at play (i.e., decomposition of kerogen or carbonate dissolution). The sources of sulphur in the produced H2S were investigated through isotopic analyses coupled with scanning electron microscopy, energy dispersive spectroscopy, and mineralogy by X-ray diffraction. The Montney Formation in BC can contain small discrete amounts of sulphur in the form of anhydrite as shown by XRD and SEM-EDX results. Sulphur isotopic analyses indicate that the most likely source of sulphur is from Triassic rocks, in particular, the Charlie Lake Formation, due to its close proximity, its high concentration of anhydrite (18-42%), and the evidence that dissolved sulphate ions migrated within the groundwater in fractures and transported anhydrite into the Halfway Formation and into the Montney Formation. The isotopic signature shows the sulphur isotopic ratio of the anhydrite in the Montney Formation is in the same range as the sulphur within the H2S gas and is a lighter ratio than what is found in Devonian anhydrite and H2S gas. This integrated study contributes to a better understanding of the hydrocarbon system for enhancing the efficiency of and optimizing the planning of drilling and production operations. Operators in BC should include mapping of the Charlie Lake evaporites and structural elements, three-dimensional seismic and sulphate ion concentrations in the connate water, when planning wells, in order to reduce the risk of encountering unexpected souring.
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Shomer, Ilan, Ruth E. Stark, Victor Gaba e James D. Batteas. Understanding the hardening syndrome of potato (Solanum tuberosum L.) tuber tissue to eliminate textural defects in fresh and fresh-peeled/cut products. United States Department of Agriculture, novembro de 2002. http://dx.doi.org/10.32747/2002.7587238.bard.
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The project sought to understand factors and mechanisms involved in the hardening of potato tubers. This syndrome inhibits heat softening due to intercellular adhesion (ICA) strengthening, compromising the marketing of industrially processed potatoes, particularly fresh peeled-cut or frozen tubers. However, ICA strengthening occurs under conditions which are inconsistent with the current ideas that relate it to Ca-pectate following pectin methyl esterase (PME) activity or to formation of rhamnogalacturonan (RG)-II-borate. First, it was necessary to induce strengthening of the middle lamellar complex (MLX) and the ICA as a stress response in some plant parenchyma. As normally this syndrome does not occur uniformly enough to study it, we devised an efficient model in which ICA-strengthening is induced consistently under simulated stress by short-chain, linear, mono-carboxylic acid molecules (OAM), at 65 oC [appendix 1 (Shomer&Kaaber, 2006)]. This rapid strengthening was insufficient for allowing the involved agents assembly to be identifiable; but it enabled us to develop an efficient in vitro system on potato tuber parenchyma slices at 25 ºC for 7 days, whereas unified stress was reliably simulated by OAMs in all the tissue cells. Such consistent ICA-strengthening in vitro was found to be induced according to the unique physicochemical features of each OAM as related to its lipophilicity (Ko/w), pKa, protonated proportion, and carbon chain length by the following parameters: OAM dissociation constant (Kdiss), adsorption affinity constant (KA), number of adsorbed OAMs required for ICA response (cooperativity factor) and the water-induced ICA (ICAwater). Notably, ICA-strengthening is accompanied by cell sap leakage, reflecting cell membrane rupture. In vitro, stress simulation by OAMs at pH<pKa facilitated the consistent assembly of ICAstrengthening agents, which we were able to characterize for the first time at the molecular level within purified insoluble cell wall of ICA-strengthened tissue. (a) With solid-state NMR, we established the chemical structure and covalent binding to cell walls of suberin-like agents associated exclusively with ICA strengthening [appendix 3 (Yu et al., 2006)]; (b) Using proteomics, 8 isoforms of cell wall-bound patatin (a soluble vacuolar 42-kDa protein) were identified exclusively in ICA-strengthened tissue; (c) With light/electron microscopy, ultrastructural characterization, histochemistry and immunolabeling, we co-localized patatin and pectin in the primary cell wall and prominently in the MLX; (d) determination of cell wall composition (pectin, neutral sugars, Ca-pectate) yielded similar results in both controls and ICA-strengthened tissue, implicating factors other than PME activity, Ca2+ or borate ions; (e) X-ray powder diffraction experiments revealed that the cellulose crystallinity in the cell wall is masked by pectin and neutral sugars (mainly galactan), whereas heat or enzymatic pectin degradation exposed the crystalline cellulose structure. Thus, we found that exclusively in ICA-strengthened tissue, heat-resistant pectin is evident in the presence of patatin and suberinlike agents, where the cellulose crystallinity was more hidden than in fresh control tissue. Conclusions: Stress response ICA-strengthening is simulated consistently by OAMs at pH< pKa, although PME and formation of Ca-pectate and RG-II-borate are inhibited. By contrast, at pH>pKa and particularly at pH 7, ICA-strengthening is mostly inhibited, although PME activity and formation of Ca-pectate or RG-II-borate are known to be facilitated. We found that upon stress, vacuolar patatin is released with cell sap leakage, allowing the patatin to associate with the pectin in both the primary cell wall and the MLX. The stress response also includes formation of covalently bound suberin-like polyesters within the insoluble cell wall. The experiments validated the hypotheses, thus led to a novel picture of the structural and molecular alterations responsible for the textural behavior of potato tuber. These findings represent a breakthrough towards understanding of the hardening syndrome, laying the groundwork for potato-handling strategies that assure textural quality of industrially processed particularly in fresh peeled cut tubers, ready-to-prepare and frozen preserved products.
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Klammler, Harald. Introduction to the Mechanics of Flow and Transport for Groundwater Scientists. The Groundwater Project, 2023. http://dx.doi.org/10.21083/gxat7083.
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Starting from Newton’s laws of motion and viscosity, this book is an introduction to fundamental aspects of fluid dynamics that are most relevant to groundwater scientists. Based on a perspective of driving versus resisting forces that govern the motion of a fluid, the author derives Darcy’s law for flow through porous media by drawing an analogy to Bernoulli’s law for fluid with negligible viscosity. By combining the effects of gravity and pressure, the author identifies hydraulic head as a convenient numerical quantity to represent the force driving groundwater flow. In contrast to the physical derivation of hydraulic head, hydraulic conductivity emerges as a parameter related to the resisting frictional forces between the mobile fluid and the stationary porous medium. These frictional seepage forces also affect the effective stress state of the porous medium, thus establishing a link to soil stability and quicksand formation. Combining Darcy’s law with the law of mass conservation leads the reader to the fundamental equations of saturated groundwater flow. Finally, the effects of capillary forces are included to establish the governing equations for unsaturated and multi-phase flow. Throughout the book, the author focuses on thoroughly illustrating and deriving the equations while applying order of magnitude analyses. This approach makes it possible to extract the most information, for example in terms of the scale of response time, without requiring explicit solutions. A number of boxes and solved exercises contain further details and links to practical applications such as the water table ratio that reflects ‘fullness’ of an aquifer and the performance of slug tests for in situ measurement of hydraulic conductivity. This book makes an important contribution to groundwater science by providing a progressive introductory explanation of the physical mechanics of groundwater flow and the accompanying socioeconomic and ecological problems that may arise.