Modelling in-situ upgrading of heavy oil using operator splitting method     

Julien Maes  Ann H. Muggeridge  Matthew D. Jackson  Michel Quintard  Alexandre Lapene 《Computational Geosciences》2016,20(3):581-594

The in-situ upgrading (ISU) of bitumen and oil shale is a very challenging process to model numerically because of the large number of components that need to be modelled using a system of equations that are both highly non-linear and strongly coupled. Operator splitting methods are one way of potentially improving computational performance. Each numerical operator in a process is modelled separately, allowing the best solution method to be used for the given numerical operator. A significant drawback to the approach is that decoupling the governing equations introduces an additional source of numerical error, known as the splitting error. The best splitting method for modelling a given process minimises the splitting error whilst improving computational performance compared to a fully implicit approach. Although operator splitting has been widely used for the modelling of reactive-transport problems, it has not yet been applied to the modelling of ISU. One reason is that it is not clear which operator splitting technique to use. Numerous such techniques are described in the literature and each leads to a different splitting error. While this error has been extensively analysed for linear operators for a wide range of methods, the results cannot be extended to general non-linear systems. It is therefore not clear which of these techniques is most appropriate for the modelling of ISU. In this paper, we investigate the application of various operator splitting techniques to the modelling of the ISU of bitumen and oil shale. The techniques were tested on a simplified model of the physical system in which a solid or heavy liquid component is decomposed by pyrolysis into lighter liquid and gas components. The operator splitting techniques examined include the sequential split operator (SSO), the Strang-Marchuk split operator (SMSO) and the iterative split operator (ISO). They were evaluated on various test cases by considering the evolution of the discretization error as a function of the time-step size compared with the results obtained from a fully implicit simulation. We observed that the error was least for a splitting scheme where the thermal conduction was performed first, followed by the chemical reaction step and finally the heat and mass convection operator (SSO-CKA). This method was then applied to a more realistic model of the ISU of bitumen with multiple components, and we were able to obtain a speed-up of between 3 and 5.  相似文献   

Agonistic effect of imidazole and triazole fungicides on in vitro oocyte maturation in rainbow trout (Oncorhynchus mykiss)     

Gilles Monod  Hlne Rime  Julien Bobe  Bernard Jalabert 《Marine environmental research》2004,58(2-5):143

The purpose of the present study was to assess the in vitro effect of some imidazole (prochloraz, imazalil) and triazole (epoxiconazole) agricultural fungicides on gonadotropin-induced oocyte maturation in rainbow trout. Results show that prochloraz, epoxiconazole and imazalil strongly potentiated the induction of oocyte maturation by gonadotropin in a dose-dependent manner. Furthermore, 10⁻⁵ M prochloraz and epoxiconazole alone induced oocyte maturation. The mRNA biosynthesis inhibitor, actinomycin , completely inhibited oocyte maturation induced by fungicides, suggesting that the gonadotropin-like effect of these chemicals is at least dependent on de novo gene expression.  相似文献   

Neogene exhumation and relief evolution in the eastern Betics (SE Spain): Insights from the Sierra de Gador          下载免费PDF全文

Marianne Janowski  Nicolas Loget  Cécile Gautheron  Jocelyn Barbarand  Nicolas Bellahsen  Jean Van Den Driessche  Julien Babault  Bertrand Meyer 《地学学报》2017,29(2):91-97

The Betics are a key area to study an orogenic landscape disrupted by late‐orogenic extension. New low‐temperature thermochronology (LTT) data (AHe and AFT) coupled with geomorphic constraints in the Sierra de Gador (Alpujarride complex) are used to reconstruct the cooling history and evolution of relief during the Neogene. We document three stages: (1) a fast cooling event between 23 and 16 Ma associated with the well‐known extensive tectonic exhumation of the Alpujarride unit, (2) a period of slow cooling between 16 and 7.2 Ma related to a planation event and (3) a post‐7.2 Ma surface uplift associated with the inversion of the Alboran domain undetected by LTT. The planation event followed by this late uplift can explain the occurrence of inherited low‐relief surfaces overlain by Tortonian–Messinian platform deposits at the top of the range. Finally, we propose that the Sierra de Gador is a more transient landscape than the nearby Sierra Nevada.  相似文献   

Influence of the El Niño/Southern Oscillation on South Korean streamflow variability          下载免费PDF全文

Jai Hong Lee  Pierre Y. Julien 《水文研究》2017,31(12):2162-2178

Deciphering the mechanisms through which the El Niño/Southern Oscillation (ENSO) affects hydrometeorological parameters in the tropics and extratropics is of great interest. We investigate climatic teleconnections between warm or cold phases of ENSO and streamflow patterns over South Korea using an empirical methodology designed to detect regions showing a strong and consistent hydroclimatic signal associated with ENSO. We calculate not only spatial coherence values by monthly streamflow composite formed over 2‐year ENSO cycle and the first harmonic fit to detect candidate regions but also temporal consistency rates by aggregate composite and index time series to determine core regions. As a result, the core regions, namely, the Han river basin and the Nakdong river basin, are detected with a high level of response of ENSO phenomena to streamflow patterns. The ENSO composites for both core regions indicate drier (wetter) conditions in early autumn of the warm (cold) episode years and wetter (drier) conditions from winter to spring of the following year. For both regions, the spatial coherences are over 92% (82%) and the temporal consistencies are 71% (75%) during the El Niño (La Niña) events. In addition, for the core regions identified by composite‐harmonic analysis for both extreme episodes, the results of comparative analyses by using correlation, annual cycle, and Wilcoxon rank sum test indicate that 2 opposite phases‐streamflow relationships have a tendency of sign reversal of the streamflow anomaly. Also, the positive departures during the El Niño years show more coherent and strong responses than the negative anomalies in the La Niña events. In conclusion, South Korea experiences climatic teleconnection between ENSO forcing and midlatitude streamflow patterns.  相似文献   

Carbon and suspended sediment transport in an impounded alpine river (Isère,France)     

Julien Némery  Vincent Mano  Alexandra Coynel  Henri Etcheber  Florentina Moatar  Michel Meybeck  Philippe Belleudy  Alain Poirel 《水文研究》2013,27(17):2498-2508

Carbon and total suspended sediment (TSS) loads were investigated from April 2006 to March 2008 in the mountainous watershed of the Isère River, French Alps (5570 km²). The river bed has been highly impounded for hydroelectricity production during the last century. Hydraulic flushes are managed every year to prevent TSS storage within upstream dams. The Isère River has been instrumented for high‐frequency monitoring of water, TSS by turbidity and carbon (organic, inorganic, dissolved and particulate) in order to evaluate the impact of natural floods and hydraulic flushes on annual loads. Annual TSS load which was estimated between 1.3 and 2.3 MT y^?1 (i.e. 233 to 413 T km^?2 y^?1) highlighted the high erodibility of the Isère watershed. Annual carbon load was estimated between 173 10³ T y^?1 and 199 10³ T y^?1 (i.e 31 to 36 T km^?2 y^?1). About 80% of the annual carbon loads were inorganic. The impact of hydraulic flushes on annual loads appeared limited (less than 3% for annual TSS load and about 1.5% for annual carbon load), whereas the most important natural flood event contributed to 20% of the annual TSS load and 10% of the annual carbon load. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Accretion, feedback and galaxy bimodality: a comparison of the GalICS semi-analytic model and cosmological SPH simulations   总被引：1，自引：0，他引：1  

Andrea Cattaneo  Jérémy Blaizot  David H. Weinberg  Dusan Kere&#;  Stéphane Colombi  Romeel Davé  Julien Devriendt  Bruno Guiderdoni  Neal Katz 《Monthly notices of the Royal Astronomical Society》2007,377(1):63-76

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The relationship between African easterly waves and daily rainfall over West Africa: observations and regional climate simulations     

Julien Crétat  Edward K. Vizy  Kerry H. Cook 《Climate Dynamics》2015,44(1-2):385-404

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Did Saturn's rings form during the Late Heavy Bombardment?     

Sébastien Charnoz  Alessandro Morbidelli  Julien Salmon 《Icarus》2009,199(2):413-711

The origin of Saturn's massive ring system is still unknown. Two popular scenarios—the tidal splitting of passing comets and the collisional destruction of a satellite—rely on a high cometary flux in the past. In the present paper we attempt to quantify the cometary flux during the Late Heavy Bombardment (LHB) to assess the likelihood of both scenarios. Our analysis relies on the so-called “Nice model” of the origin of the LHB [Tsiganis, K., Gomes, R., Morbidelli, A., Levison, H.F., 2005. Nature 435, 459-461; Morbidelli, A., Levison, H.H., Tsiganis, K., Gomes, R., 2005. Nature 435, 462-465; Gomes, R., Levison, H.F., Tsiganis, K., Morbidelli, A., 2005. Nature 435, 466-469] and on the size distribution of the primordial trans-neptunian planetesimals constrained in [Charnoz, S., Morbidelli, A., 2007. Icarus 188, 468-480]. We find that the cometary flux on Saturn during the LHB was so high that both scenarios for the formation of Saturn rings are viable in principle. However, a more detailed study shows that the comet tidal disruption scenario implies that all four giant planets should have comparable ring systems whereas the destroyed satellite scenario would work only for Saturn, and perhaps Jupiter. This is because in Saturn's system, the synchronous orbit is interior to the Roche Limit, which is a necessary condition for maintaining a satellite in the Roche Zone up to the time of the LHB. We also discuss the apparent elimination of silicates from the ring parent body implied by the purity of the ice in Saturn's rings. The LHB has also strong implications for the survival of the saturnian satellites: all satellites smaller than Mimas would have been destroyed during the LHB, whereas Enceladus would have had from 40% to 70% chance of survival depending on the disruption model. In conclusion, these results suggest that the LHB is the “sweet moment” for the formation of a massive ring system around Saturn.  相似文献   

Latitudinal librations of Mercury with a fluid core     

Julien Dufey  Benoît Noyelles  Nicolas Rambaux 《Icarus》2009,203(1):1-12

In the framework of the space missions to Mercury, an accurate model of rotation is needed. Librations around the 3:2 spin-orbit resonance as well as latitudinal librations have to be predicted with the best possible accuracy. In this paper, we use a Hamiltonian analysis and numerical integrations to study the librations of Mercury, both in longitude and latitude. Due to the proximity of the period of the free libration in longitude to the orbital period of Jupiter, the 88-day and 11.86-year contributions dominate Mercury’s libration in longitude (with the Hermean parameters chosen). The amplitude of the libration in latitude is much smaller (under 1 arcsec) and should not be detected by the space missions. Nevertheless, we point out that this amplitude could be much larger (up to several tens of arcsec) if the free period related to the libration in latitude approaches the period of the Jupiter-Saturn Great Inequality (883 years). Given the large uncertainties on the planetary parameters, this new resonant forcing on Mercury’s libration in latitude should be borne in mind.  相似文献   

A multi-model ensemble approach for assessment of climate change impact on surface winds in France   总被引：2，自引：1，他引：1  

Julien Najac  Julien Boé  Laurent Terray 《Climate Dynamics》2009,32(5):615-634

Statistical downscaling of 14 coupled atmosphere-ocean general circulation models (AOGCM) is presented to assess potential changes of the 10 m wind speeds in France. First, a statistical downscaling method is introduced to estimate daily mean 10 m wind speed at specific sites using general circulation model output. Daily 850 hPa wind field has been selected as the large scale circulation predictor. The method is based on a classification of the daily wind fields into a few synoptic weather types and multiple linear regressions. Years are divided into an extended winter season from October to March and an extended summer season from April to September, and the procedure is conducted separately for each season. ERA40 reanalysis and observed station data have been used to build and validate the downscaling algorithm over France for the period 1974–2002. The method is then applied to 14 AOGCMs of the coupled model intercomparison project phase 3 (CMIP3) multi-model dataset. Three time periods are focused on: a historical period (1971–2000) from the climate of the twentieth century experiment and two climate projection periods (2046–2065 and 2081–2100) from the IPCC SRES A1B experiment. Evolution of the 10 m wind speed in France and associated uncertainties are discussed. Significant changes are depicted, in particular a decrease of the wind speed in the Mediterranean area. Sources of those changes are investigated by quantifying the effects of changes in the weather type occurrences, and modifications of the distribution of the days within the weather types.  相似文献