491 research outputs found
Finite element modelling of immiscible two-phase flow in oil reservoirs
Reservoir simulators utilize numerical techniques to solve the governing
equations of fluid flow in porous media and they are essential tool for oil and
gas fields development. In practical reservoir simulation, the finite
difference method (FDM) is the common numerical technique owing to its
simplicity in application. In this paper, we introduce the finite element
method (FEM) as a numerical tool to simulate an example in 3D and prior to
that, Buckley-Leverett problem is used to validate using a commercial FEM-based
software package that is applied through this paper. To achieve the proposed
target, the mathematical model of the immiscible-two phase problem is reviewed
and formulated to be applied easily in the proposed software. Immiscible
two-phase flow in 3D is simulated on the 1/4th inverted five-spot benchmark and
the results are shown and discussed. The results show that the FEM can be used
efficiently to simulated immiscible two-phase flow in oil reservoirs with an
acceptable CPU time and this is due to faster solvers advances in the last few
years.Comment: 26 page
Nodular eruptions as a rare complication of botulinum neurotoxin type-A : case series and review of literature
Nodular eruption after botulinum neurotoxin type-A (BoNT-A) treatment is exceedingly rare, and the pathogenesis is poorly understood. This case series reports three patients that developed nodular eruptions following administration of Botox® (onabotulinum neurotoxin type A (ONA) injections). These patients had undergone multiple treatments before and after development of the eruptions which were uneventful. In addition to this, we have reviewed the published literature regarding this condition and have compared and contrasted the similarities and differences with regards to the clinical presentation and treatment with our patient cohort. This case series aims to raise awareness of this rare condition, its importance in relation to patient consent and provides a simplified management approach based on our experience. Further evaluation is needed to determine treatment consensus but conducting such research may prove to be challenging due to this condition being an infrequent encounter
Neutron Transfer reactions induced by 8Li on 9Be
Angular distributions for the elastic scattering of 8Li on 9Be and the
neutron transfer reactions 9Be(8Li,7Li)10Be and 9Be(8Li,9Li)8Be have been
measured with a 27 MeV 8Li radioactive nuclear beam. Spectroscopic factors for
8Li|n=9Li and 7Li|n=8Li bound systems were obtained from the comparison between
the experimental differential cross section and finite-range DWBA calculations
with the code FRESCO. The spectroscopic factors obtained are compared to shell
model calculations and to other experimental values from (d,p) reactions. Using
the present values for the spectroscopic factor, cross sections for the direct
neutron-capture reactions 7Li(n,g)8Li and 8Li(n,g)9Li were calculated in the
framework of a potential model.Comment: 24 pages, 8 Figures, submitted as regular article to PR
State-space distribution and dynamical flow for closed and open quantum systems
We present a general formalism for studying the effects of dynamical
heterogeneity in open quantum systems. We develop this formalism in the state
space of density operators, on which ensembles of quantum states can be
conveniently represented by probability distributions. We describe how this
representation reduces ambiguity in the definition of quantum ensembles by
providing the ability to explicitly separate classical and quantum sources of
probabilistic uncertainty. We then derive explicit equations of motion for
state space distributions of both open and closed quantum systems and
demonstrate that resulting dynamics take a fluid mechanical form analogous to a
classical probability fluid on Hamiltonian phase space, thus enabling a
straightforward quantum generalization of Liouville's theorem. We illustrate
the utility of our formalism by analyzing the dynamics of an open two-level
system using the state-space formalism that are shown to be consistent with the
derived analytical results
Introducing dip pen nanolithography as a tool for controlling stem cell behaviour: unlocking the potential of the next generation of smart materials in regenerative medicine (vol 10, pg 1662, 2010)
Correction for ‘Introducing dip pen nanolithography as a tool for controlling stem cell behaviour: unlocking the potential of the next generation of smart materials in regenerative medicine’ by Judith M. Curran et al., Lab Chip, 2010, 10, 1662–1670.</p
Integrity Experiments for Geological Carbon Storage (GCS) in Depleted Hydrocarbon Reservoirs: Wellbore Components under Cyclic CO2 Injection Conditions
Integrity of wellbores and near wellbore processes are crucial issues in geological carbon storage (GCS) projects as they both define the confinement and injectivity of CO2. For the proper confinement of CO2, any flow of CO2 along the wellbore trajectory must be prevented using engineered barriers. The effect of cyclic stimuli on wellbore integrity, especially in the context of GCS projects, has been given less attention. In this study, the effect of pressure- and temperature-cycling on two types of wellbore composites (i.e., casing-cement and cement-caprock) have been investigated experimentally in small- and large-scale laboratory setups. The experiments have been carried out by measuring the effective permeability of the composites under pressure and thermal cyclic conditions. Furthermore, the permeability of individual samples (API class G and HMR+ cement and caprock) was measured and compared to the permeability of the composites. The results indicate that the permeability of API class G cement when exposed to CO2 is in the order of 10−20 m2 (10−5 mD) as a result of the chemical reaction between the cement and CO2. In addition, the tightness of the composite cement–rock has been confirmed, while the permeability of the composite casing–cement falls within the acceptable range for tight cement and the CO2 flow was identified to occur through or close to the interface casing–cement. Results from thermal cycling within the range −9 to 14 °C revealed no significant effect on the integrity of the bond casing–cement. In contrast, pressure cycling experiments showed that the effective pressure has a larger influence on the permeability. The potential creation of micro-cracks under pressure variations may require some time for complete closing. In conclusion, the pressure and temperature cycling from this study did not violate the integrity of the casing–cement composite sample as the permeability remained low and within the acceptable range for wellbore cement.Integrity Experiments for Geological Carbon Storage (GCS) in Depleted Hydrocarbon Reservoirs: Wellbore Components under Cyclic CO2 Injection ConditionspublishedVersio
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