1,711 research outputs found
Reduced-Order Modelling for Production Optimisation
No full textProduction optimisation of a reservoir simulation problem can be very computationally demanding as the reservoir model may contain many variables and nonlinearities, thus many iterations may be needed to obtain an optimal production schedule. Using Proper Orthogonal Decomposition and Trajectory Piecewise Linearization (POD-TPWL) developed in [1] and [2], simulations were performed on the Delft Egg model 100-200 times faster than the high-fidelity simulation with reasonable accuracy, depending on the distance from the trained solution. Production optimisation was performed using the gradient-based adjoint method. A reduced version of the adjoint equation was used by incorporating POD, as presented in [3] and by performing a first-order Taylor series expansion around a training point (similar to TPWL). This method allowed for time gains of 50-100 times when compared to the high-fidelity adjoint method. The results from the high-fidelity production optimisation compared with POD-TPWL showed a similar Net Present Value (NPV) for both optimisation methods, with an error of 0.1% between the two-values. However, the optimal injection schedules were not the same. When the high-fidelity model was run using the input schedules from POD-TPWL optimisation, the error in NPV was 4%. The speed-up observed for the optimisation loop using POD-TPWL was 6 times faster than the high-fidelity model. This is due to the number of snapshots that needed to be generated and the processing of the data from these snapshots. Robust optimisation was performed on the Egg model ensemble using a POD-TPWL model incorporating geological model parameters, states and well controls. Results showed a 0.7% deviation from the mean NPV value calculated in MoReS and a 4 million dollar increase in the standard deviation of the NPV. POD-TPWL was able to complete the robust optimisation 25 times faster than a high-fidelity simulation. POD-TPWL shows promise as a reduced-order modelling application for reservoir simulation and production optimisation. The accuracy needs to be improved in order to move to an operational application.Petroleum EngineeringGeoscience & EngineeringCivil Engineering and Geoscience
Discussion of bedload movement formulas of Kalinske, Einstein and Meyer-Peter and Müller and their application to recent measurements of beload in the rivers in Holland
No full textOverview of sediment transport formulas and comparison with measurements in Waal and Rijn river in the Netherlands
A robust multigrid method for a discretization of the incompressible Navier-Stokes equations in general coordinates
No full text
Development of Hurricane flood protection for Texas City, Texas
No full textThe purpose of this paper is to present the hydraulic problems relating to the computation of hurricane surge, hurricane waves, runup of the waves for providing hurricane flood protection at Texas City, Texas, as well as the effects of rainfall upon the protected area during periods of normal and high tides. The problems of providing protection are discussed, and information is presented on structures that were designed for the hurricane protection project
Onderzoek naar signaalgeneratie met behulp van fasedraaiers ten behoeve van reflectie-compensatie in een F.M.-C.W. radarsysteem
No full textVoor onderzoek aan de troposfeer wordt gebruik gemaakt van een F.M.-C.W. radarsysteem. Een aspect van het radarsysteem waarnaar nog onderzoek gewenst is, is de onderdrukking van de overspraak van zender naar ontvanger, en van sterke reflecties aan nabije obstakels: deze signalen houden nl. het gevaar in van oversturing van de ontvanger. Dit aspect is met name van belang voor een mogelijk nog te realiseren F.M. -C.V. radarsysteem met één antenne…Applied SciencesElectrotechniekTelecommunicatie- en Verkeersbegeleidingssysteme
Nota, betreffende berekeningen omtrent rivierverbeteringen: opgemaakt door den ingenieur van den Rijkswaterstaat C.W. Lely
No full textHydraulische basis voor de normalisatiewerken van de grote rivieren. Berekingen van optimale breedte en diepte
Reversing radial segregation and suppressing morphological instability during vertical Bridgman crystal growth by rotation
No full textDuring vertical Bridgman growth of an alloy crystal, local accumulation of solute at the interface center due to
buoyancy often causes formation of a deep depression or pit and accelerates morphological instability. Through
visualization of the freezing interface during directional solidification of succinonitrile containing ethanol on a rotating
table, it was shown that rotation about the ampoule axis might reverse solute distribution and remove pit formation.
Simulation was also conducted to explain the observations
Tomato EF-Tsmt, a functional mitochondrial translation elongation factor from higher plants
Full text linkEthylene-induced ripening in tomato (Lycopersicon esculentum) resulted in the accumulation of a transcript
designated LeEF-Tsmt that encodes a protein with significant homology to bacterial Ts translational elongation
factor (EF-Ts). Transient expression in tobacco and sunflower protoplasts of full-length and truncated LeEF-Tsmt-
GFP fusion constructs and confocal microscopy observations clearly demonstrated the targeting of LeEF-Tsmt
to mitochondria and not to chloroplasts and the requirement for a signal peptide for the proper sorting of the
protein. Escherichia coli recombinant LeEF-Tsmt co-eluted from Ni-NTA resins with a protein corresponding to
the molecular weight of the elongation factor EF-Tu of E. coli, indicating an interaction with bacterial EF-Tu.
Increasing the GDP concentration in the extraction buffer reduced the amount of EF-Tu in the purified LeEF-Tsmt
fraction. The purified LeEF-Tsmt stimulated the poly(U)-directed polymerization of phenylalanine 10-fold in the
presence of EF-Tu. Furthermore, LeEF-Tsmt was capable of catalysing the nucleotide exchange reaction with E.
coli EF-Tu. Altogether, these data demonstrate that LeEF-Tsmt encodes a functional mitochondrial EF-Ts. LeEFTsmt
represents the first mitochondrial elongation factor to be isolated and functionally characterized in higher
plants
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