Micro-mechanical prediction of the effect of surfactant concentration and external friction on the visco-elasto-plastic response of an aqueous foam

Abstract Several gas Enhanced Oil Recovery (EOR) pilots enhanced with aqueous-foam based conformance solutions have been implemented in the last 30 years. While these pilots were technically successful, there were economic challenges limiting their commercial viability. Many of these pilots were implemented with water-soluble foaming surfactants that can get adversely affected by near wellbore gas-water gravity segregation and adsorption loss up to 90% of the injected surfactant. Novel, gas-soluble surfactants can be injected with the gas phase where these surfactants are carried with the gas to thief zones faster and deeper with relatively lower adsorption to the rock surface. However, the conventional foam modeling approach relied only on the surfactant concentration in brine to determine foam strength, which adversely predicted the performance of gas soluble surfactants. With proven laboratory evaluations and multiple successful field implementations, the advantages of low adsorbing and gas soluble surfactants cannot be ignored. In this paper, the advantages of surfactant partitioning to the gas phase are confirmed by correcting the conventional foam modeling approach while simulating 1D transport of CO2-foam displacing brine in porous media. An empirical foam model was developed from the lab scale core flooding work of CO2foam transport through porous media using a novel gas-soluble foaming surfactant. While investigating the performance of gas soluble surfactants, global surfactant concentration was used to determine foam strength as the surfactant can transport to the gas-water interface from both the phases. Lab experiments and simulations with an improved foam modeling approach confirmed that a higher gas phase partitioning surfactant generated robust foam and deeper foam propagation while injecting surfactant with CO2in a water saturated core. In addition, comparing three partition coefficient scenarios around 1 on mass basis, the higher gas phase partitioning surfactant showed the larger delay in gas breakthrough. Overall, the simulation results with our better modeling approach do support the advantages of the higher gas phase surfactant partitioning in deeper foam transport and conformance enhancement for the gas-EOR technology.

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Prospective Memory Development Across the Lifespan

European Psychologist ◽

10.1027/1016-9040/a000380 ◽

2020 ◽

Vol 25 (3) ◽

pp. 162-173 ◽

Cited By ~ 1

Author(s):

Sascha Zuber ◽

Matthias Kliegel

Keyword(s):

Prospective Memory ◽

Healthy Aging ◽

Present Model ◽

Current Knowledge ◽

Well Being ◽

The Elderly ◽

Cognitive Factors ◽

Everyday Functioning ◽

Integrative Framework

Abstract. Prospective Memory (PM; i.e., the ability to remember to perform planned tasks) represents a key proxy of healthy aging, as it relates to older adults’ everyday functioning, autonomy, and personal well-being. The current review illustrates how PM performance develops across the lifespan and how multiple cognitive and non-cognitive factors influence this trajectory. Further, a new, integrative framework is presented, detailing how those processes interplay in retrieving and executing delayed intentions. Specifically, while most previous models have focused on memory processes, the present model focuses on the role of executive functioning in PM and its development across the lifespan. Finally, a practical outlook is presented, suggesting how the current knowledge can be applied in geriatrics and geropsychology to promote healthy aging by maintaining prospective abilities in the elderly.

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DISSIPATIVE EFFECTS IN PROJECTILE FRAGMENTATION AND PARTICLES EVAPORATION

Le Journal de Physique Colloques ◽

10.1051/jphyscol:1987225 ◽

1987 ◽

Vol 48 (C2) ◽

pp. C2-175-C2-178

Author(s):

A. BONASERA ◽

M. DI TORO ◽

C. GREGOIRE

Keyword(s):

Projectile Fragmentation ◽

Dissipative Effects

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Fatigue Investigation of Elastomeric Structures

Tire Science and Technology ◽

10.2346/1.3481658 ◽

2010 ◽

Vol 38 (3) ◽

pp. 194-212 ◽

Cited By ~ 11

Author(s):

Bastian Näser ◽

Michael Kaliske ◽

Will V. Mars

Keyword(s):

Fatigue Crack ◽

Fatigue Crack Growth ◽

Crack Growth ◽

Material Behavior ◽

Period Effect ◽

Numerical Representation ◽

Material Force ◽

Strain Behavior ◽

Dissipative Effects ◽

Elastomeric Materials

Abstract Fatigue crack growth can occur in elastomeric structures whenever cyclic loading is applied. In order to design robust products, sensitivity to fatigue crack growth must be investigated and minimized. The task has two basic components: (1) to define the material behavior through measurements showing how the crack growth rate depends on conditions that drive the crack, and (2) to compute the conditions experienced by the crack. Important features relevant to the analysis of structures include time-dependent aspects of rubber’s stress-strain behavior (as recently demonstrated via the dwell period effect observed by Harbour et al.), and strain induced crystallization. For the numerical representation, classical fracture mechanical concepts are reviewed and the novel material force approach is introduced. With the material force approach at hand, even dissipative effects of elastomeric materials can be investigated. These complex properties of fatigue crack behavior are illustrated in the context of tire durability simulations as an important field of application.

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Application of an Element-free Galerkin Method to Water Wave Propagation Problems

Archives of Hydro-Engineering and Environmental Mechanics ◽

10.2478/heem-2013-0010 ◽

2014 ◽

Vol 60 (1-4) ◽

pp. 87-105 ◽

Cited By ~ 3

Author(s):

Ryszard Staroszczyk

Keyword(s):

Wave Propagation ◽

Galerkin Method ◽

Present Model ◽

Free Surface Elevation ◽

Element Free Galerkin Method ◽

Plane Flow ◽

Element Free Galerkin ◽

Proposed Model ◽

Sloping Bed ◽

Element Free

Abstract The paper is concerned with the problem of gravitational wave propagation in water of variable depth. The problem is solved numerically by applying an element-free Galerkin method. First, the proposed model is validated by comparing its predictions with experimental data for the plane flow in water of uniform depth. Then, as illustrations, results of numerical simulations performed for plane gravity waves propagating through a region with a sloping bed are presented. These results show the evolution of the free-surface elevation, displaying progressive steepening of the wave over the sloping bed, followed by its attenuation in a region of uniform depth. In addition, some of the results of the present model are compared with those obtained earlier by using the conventional finite element method.

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The Numerical Modeling of Spherical Explosion in the Foam

Proceedings of the Mavlyutov Institute of Mechanics ◽

10.21662/uim2016.1.009 ◽

2016 ◽

Vol 11 (1) ◽

pp. 60-65 ◽

Cited By ~ 3

Author(s):

R.Kh. Bolotnova ◽

E.F. Gainullina

Keyword(s):

Shock Wave ◽

Numerical Modeling ◽

Initial Pressure ◽

Water Volume ◽

Symmetric Model ◽

Two Phase ◽

Experimental Conditions ◽

Initial Water ◽

Aqueous Foam ◽

Spherical Explosion

The spherical explosion propagation process in aqueous foam with the initial water volume content α10=0.0083 corresponding to the experimental conditions is analyzed numerically. The solution method is based on the one-dimensional two-temperature spherically symmetric model for two-phase gas-liquid mixture. The numerical simulation is built by the shock capturing method and movable Lagrangian grids. The amplitude and the width of the initial pressure pulse are found from the amount of experimental explosive energy. The numerical modeling results are compared to the real experiment. It’s shown, that the foam compression in the shock wave leads to the significant decrease in velocity and in amplitude of the shock wave.

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Fabrication, Optimization and Characterization of Paclitaxel and Spirulina Loaded Nanoparticles for Enhanced Oral Bioavailability

Current Nanoscience ◽

10.2174/1573413716666200203115101 ◽

2020 ◽

Vol 16 (5) ◽

pp. 723-733

Author(s):

Keerthi G.S. Nair ◽

Yamuna Ravikumar ◽

Sathesh Kumar Sukumaran ◽

Ramaiyan Velmurugan

Keyword(s):

Gastric Cancer ◽

Oral Bioavailability ◽

Surfactant Concentration ◽

Polymer Concentration ◽

Central Composite Rotatable Design ◽

Normal Cells ◽

Stirring Time ◽

Nanoparticle Formulation ◽

Central Composite

Background: Paclitaxel and spirulina when administered as nanoparticles, are potentially useful. Methods: Nanoformualtions of Paclitaxel and Spirulina for gastric cancer were formulated and optimized with Central composite rotatable design (CCRD) using Response surface methodology (RSM). Results: The significant findings were the optimal formulation of polymer concentration 48 mg, surfactant concentration 45% and stirring time of 60 min gave rise to the EE of (98.12 ± 1.3)%, DL of (15.61 ± 1.9)%, mean diameter of (198 ± 4.7) nm. The release of paclitaxel and spirulina from the nanoparticle matrix at pH 6.2 was almost 45% and 80% in 5 h and 120 h, respectively. The oral bioavailability for the paclitaxel spirulina nanoparticles developed is 24.0% at 10 mg/kg paclitaxel dose, which is 10 times of that for oral pure paclitaxel. The results suggest that RSM-CCRD could efficiently be applied for the modeling of nanoparticles. The paclitaxel and spirulina release rate in the tumor cells may be higher than in normal cells. Paclitaxel spirulina nanoparticle formulation may have higher bioavailability and longer sustainable therapeutic time as compared with pure paclitaxel. Conclusion: Paclitaxel-Spirulina co-loaded nanoparticles could be effectively useful in gastric cancer as chemotherapeutic formulation.

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INFLUENCE OF THE DISSIPATIVE PROPERTIES OF AQUEOUS FOAM ON THE DYNAMICS OF SHOCK WAVES

Journal of Applied Mechanics and Technical Physics ◽

10.1134/s0021894420040021 ◽

2020 ◽

Vol 61 (4) ◽

pp. 510-516

Author(s):

R. Kh. Bolotnova ◽

E. F. Gainullina

Keyword(s):

Shock Waves ◽

Aqueous Foam

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Proton magnetic resonance study of the conformation of the pyrrolidine ring in some proline-thiohydantoins

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19882503 ◽

1988 ◽

Vol 53 (11) ◽

pp. 2503-2510 ◽

Cited By ~ 3

Author(s):

Jef J. M. Sleeckx ◽

Marc J. O. Anteunis ◽

Frans A. M. Borremans

Keyword(s):

Present Model ◽

Coupling Constants ◽

Proton Proton ◽

Proton Coupling ◽

Proton Magnetic Resonance Study ◽

Vicinal Proton ◽

Different Temperatures ◽

Experimental Justification ◽

State Assumption ◽

Methyl Phenyl

The conformational behaviour of a series of N-substituted thiohydantoins of proline was studied by proton NMR. The pseudorotational parameters of the proline moiety were calculated from the ten vicinal proton-proton coupling constants assuming a two state equilibrium (N ⇋ S). The effect of the different substituents (methyl, phenyl, para-nitrophenyl) at the thiohydantoin nitrogen on the conformation of the pyrrolidine rings is discussed. The spectra of proline-N-methylthiohydantoin were recorded at different temperatures in octadeuterotoluene solution. The conformational analysis of these spectra showed that the ratio of the populations of the N and S forms changes considerably with temperature, while the conformational identity of both the N and S forms remains strictly preserved. These facts provide an additional experimental justification of the two-state assumption, at least so for the present model compounds.

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