MOBILITY REDUCTION OF CO2 USING CO2 SOLUBLE SURFACTANTS

Addition of slightly CO2-soluble, brine-soluble, surfactants to high pressure CO2 for EOR may facilitate in-situ generation of CO2-in-brine foams for mobility control. These non-ionic surfactants have been demonstrated to dissolve in CO2 to concentrations of 0.1wt% at reservoir conditions and stabilize CO2-in-brine foams in a high pressure windowed cell. One such surfactant is Huntsman SURFONIC® N, a branched nonylphenol ethoxylates with averages of 12 (N-120) or 15(N-150) ethylene oxide repeat units in the hydrophile. SURFONIC® N-120 was selected for mobility reduction studies involving flow of CO2 into brine-saturated porous media. Transient mobility measurements were conducted using a water-wet Berea core (104mD), water-wet Bentheimer sandstone core (~1500mD), and several SACROC carbonate cores (3.6 and 8.9mD). The CO2 was injected into brine-saturated cores at superficial velocity of 10 ft/day, and surfactant was either not used (control), dissolved only in brine at 0.07wt%, dissolved only in CO2 at ~0.07wt%, or dissolved in brine and CO2 at 0.07wt%. In general, in-situ foam generation in relatively high permeability sandstone was evidenced during the first few pore volumes of CO2 injected by pressure drops that were 2-3 times greater than control tests regardless of what phase CO2 was in. Mobility reduction was more modest (20–50% increases in pressure drop) in lower permeability SACROC cores (3.6 and 8.9mD) when surfactant was dissolved in CO2. With surfactant dissolved in brine, pressure drops increased by a factor of 2–3 when CO2 was injected into an 8.9mD core. High pressure CT imaging of in-situ foam generation was conducted by injecting high pressure CO2 into 5wt% KI-brine-saturated Berea sandstone (3-8mD). Tests with no surfactant (control), or with surfactant dissolved either brine or CO2 at ~0.07wt%. At lower superficial velocities (0.47ft/day), in-siti foam generation was obvious only when surfactant was dissolved in brine. Higher flow rates (4.7ft/day) preferential flow of CO2 through high permeability layers and viscous fingering within layers that occurred during control tests was suppressed by addition of surfactant to either CO2 or brine. The most distinct CO2 foam front occurred with surfactant dissolved in brine

Tracing the Scenarios in Scenario-Based Product Design: a study to support scenario generation

Scenario-based design originates from the human-computer interaction and\ud software engineering disciplines, and continues to be adapted for product development. Product development differs from software development in the former’s more varied context of use, broader characteristics of users and more tangible solutions. The possible use of scenarios in product design is therefore broader and more challenging. Existing design methods that involve scenarios can be employed in many different stages of the product design process. However, there is no proficient overview that discusses a\ud scenario-based product design process in its full extent. The purposes of creating scenarios and the evolution of scenarios from their original design data are often not obvious, although the results from using scenarios are clearly visible. Therefore, this paper proposes to classify possible scenario uses with their purpose, characteristics and supporting design methods. The classification makes explicit different types of scenarios and their relation to one another. Furthermore, novel scenario uses can be referred or added to the classification to develop it in parallel with the scenario-based design\ud practice. Eventually, a scenario-based product design process could take inspiration for creating scenarios from the classification because it provides detailed characteristics of the scenario

Diagnostic applications of next generation sequencing: working towards quality standards

Over the past 6 years, next generation sequencing (NGS) has been established as a valuable high-throughput method for research in molecular genetics and has successfully been employed in the identification of rare and common genetic variations. All major NGS technology companies providing commercially available instruments (Roche 454, Illumina, Life Technologies) have recently marketed bench top sequencing instruments with lower throughput and shorter run times, thereby broadening the applications of NGS and opening the technology to the potential use for clinical diagnostics. Although the high expectations regarding the discovery of new diagnostic targets and an overall reduction of cost have been achieved, technological challenges in instrument handling, robustness of the chemistry and data analysis need to be overcome. To facilitate the implementation of NGS as a routine method in molecular diagnostics, consistent quality standards need to be developed. Here the authors give an overview of the current standards in protocols and workflows and discuss possible approaches to define quality criteria for NGS in molecular genetic diagnostics

Fundamentals of 3-D Neutron Kinetics and Current Status

This lecture includes the following topics: 1) A summary of the cell and lattice calculations used to generate the neutron reaction data for neutron kinetics, including the spectral and burn up calculations of LWR cells and fuel assembly lattices, and the main nodal kinetics parameters: mean neutron generation time and delayed neutron fraction; 2) the features of the advanced nodal methods for 3-D LWR core physics, including the treatment of partially inserted control rods, fuel assembly grids, fuel burn up and xenon and samarium transients, and ex core detector responses, that are essential for core surveillance, axial offset control and operating transient analysis; 3) the advanced nodal methods for 3-D LWR core neutron kinetics (best estimate safety analysis, real time simulation); and 4) example applications to 3-D neutron kinetics problems in transient analysis of PWR cores, including model, benchmark and operational transients without, or with simple, thermal-hydraulics feedback

Ocean Energy in Belgium - 2019

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Totally Corrective Multiclass Boosting with Binary Weak Learners

In this work, we propose a new optimization framework for multiclass boosting learning. In the literature, AdaBoost.MO and AdaBoost.ECC are the two successful multiclass boosting algorithms, which can use binary weak learners. We explicitly derive these two algorithms' Lagrange dual problems based on their regularized loss functions. We show that the Lagrange dual formulations enable us to design totally-corrective multiclass algorithms by using the primal-dual optimization technique. Experiments on benchmark data sets suggest that our multiclass boosting can achieve a comparable generalization capability with state-of-the-art, but the convergence speed is much faster than stage-wise gradient descent boosting. In other words, the new totally corrective algorithms can maximize the margin more aggressively.Comment: 11 page