bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Fabrication and Dielectric Properties of Poly(Vinylidene Fluoride Trifluoroethylene Chlorofluoroethylene) Terpolymer Nanorods
Authors: Lin Jun-Hong , Lu David Sheng-Guo , Lin Minren , Zhang Qiming 
Published: September 2010

AbstractPoly(vinylidene fluoride trifluoroethylene chlorofluoroethylene) (P(VDF-TrFE-CFE)) terpolymer nanorods embedded in Anodic Alumina Oxide( AAO) templates with pore sizes of 25, 70, and 200nm diameter were fabricated by extending the time of the wetting process. The instability of the wetting process induced the terpolymer infiltration into the inner space of tepolymer nanotubes, which formed mostly filled terpolymer nanorods. It was observed that all these nanorods embedded in AAO templates still possess relaxor ferroelectric behavior. The broad dielectric peak shifts progressively to higher temperatures with increasing frequency and the frequency- permittivity peak temperature fits well with the Vogel-Fulcher (V-F) relation. Moreover, the freezing temperature of the V-F relation is reduced, with the reduction of nanorod diameter. This indicates that the lateral confinement of the nanorods influences the relaxor ferroelectric behavior of the relaxor ferroelectric P(VDF-TrFE-CFE) terpolymer.
Functional Polymers for Advanced Lithography
Authors: Choi Kyung 
Published: September 2010

AbstractIn nanotechnology, many scientists have been seeking for new functional polymers, which can replica nano-sized features to achieve improved performances of nano-devices. Soft lithography has been widely used in replica of small features as a low cost alternative to conventional UV photolithography. However, commercial silicon rubbers, PDMS polymers, which have been used in current soft lithography, show limitations, especially for nano-resolution soft lithography. These limitations have motivated us to develop a new version of PDMS polymers to overcome those limitations and thus to extend current technology in soft lithography to the advanced level. Since the resolution of soft lithography significantly relies on stamping performance, we designed a novel PDMS prepolymer, which has photocurable cross-linkers to enhance mechanical property to improve lithographic performance and also to create photocurable capability.
Crystallization of Synthetic Hemozoin (Beta-Hematin) Nucleated at the Surface of Synthetic Neutral Lipid Bodies
Authors: Egan Timothy J , Hoang Anh N , Ncokazi Kanyile K , de Villiers Katherine A , Wright David W 
Published: September 2010

AbstractThe mechanism of formation of hemozoin, a detoxification by-product of several blood-feeding organisms including malaria parasites, has been a subject of debate; however, recent studies suggest that neutral lipids may serve as a catalyst. In this study, a model system consisting of an emulsion of synthetic lipid bodies, resembling their in vivo counterpart in composition and size, was employed to investigate the formation of β-hematin, synthetic hemozoin, at the lipid-water interface. The introduction of heme (Fe(III)PPIX) to this synthetic neutral lipid bodies system under biomimetic conditions (37°C, pH 4.8) produced beta-hematin with apparent first order kinetics and an average half life of 0.5 min. TEM of monoglycerides (MPG) extruded through a 200 nm filter with heme produced beta-hematin crystals aligned and parallel to the lipid/water interface. TEM data suggests that beta-hematin crystallizes via epitaxial nucleation at the lipid-water interface through interaction of Fe(III)PPIX with the polar head group and elongation occurs parallel this interface.
The Method of Characteristics Applied to Oil Displacement by Foam
Authors: Namdar Zanganeh M.. , Kam S.I.. I. , LaForce T.C.. C. , Rossen W.R.. R. 
Published: September 2010

Summary
Solutions obtained by the method of characteristics (MOC) provide key insights into complex foam enhanced-oil-recovery (EOR) displacements and the simulators that represent them. Most applications of the MOC to foam have excluded oil. We extend the MOC to foam flow with oil, where foam is weakened or destroyed by oil saturations above a critical oil saturation and/or weakened or destroyed at low water saturations, as seen in experiments and represented in foam simulators. Simulators account for the effects of oil and capillary pressure on foam using algorithms that bring foam strength to zero as a function of oil or water saturation, respectively. Different simulators use different algorithms to accomplish this.
We examine SAG (surfactant-alternating-gas) and continuous foam-flood (coinjection of gas and surfactant solution) processes in one dimension, using both the MOC and numerical simulation. We find that the way simulators express the negative effect of oil or water saturation on foam can have a large effect on the calculated nature of the displacement. For instance, for gas injection in a SAG process, if foam collapses at the injection point because of infinite capillary pressure, foam has almost no effect on the displacement in the cases examined here. On the other hand, if foam maintains finite strength at the injection point in the gas-injection cycle of a SAG process, displacement leads to implied success in several cases. However, successful mobility control is always possible with continuous foam flood if the initial oil saturation in the reservoir is below the critical oil saturation above which foam collapses.
The resulting displacements can be complex. One may observe, for instance, foam propagation predicted at residual water saturation, with zero flow of water. In other cases, the displacement jumps in a shock past the entire range of conditions in which foam forms. We examine the sensitivity of the displacement to initial oil and water saturations in the reservoir, the foam quality, the functional forms used to express foam sensitivity to oil and water saturations, and linear and nonlinear relative permeability models.
An Environmentally Friendly Stimulation Fluid for High-Temperature Applications
Authors: LePage J.N.. N. , De Wolf C.A.. A. , Bemelaar J.H.. H. , Nasr-El-Din H.A.. A. 
Published: September 2010

SummaryMatrix acidizing is used in carbonate formations to create flow channels from the formation to the wellbore; in sandstone formations, however, the goal is to dissolve materials that impair well performance. However, the use of acids in deep wells has some major drawbacks, including high reaction rate and corrosion to well tubulars.We have discovered a new stimulation chemical that can be used as a replacement for or in combination with acid treatments in deep wells. A polyacid whose structure allows for acidification is described. The polyacidic chelate L-glutamic acid, N, N-diacetic acid (GLDA) is manufactured from L-glutamic acid (MSG). The chelate-based fluid very effectively dissolves CaCO3, and it is less corrosive to the equipment and easy to handle.This paper discusses the reaction of the new chelate, GLDA, with calcite and compares its performance with other available chelates, including ethylenediaminetetraacetic acid (EDTA), hydroxy-ethylethylenediaminetriacetic acid (HEDTA), nitrilotriacetic acid (NTA), and ethanoldiglycine (EDG). GLDA dissolves calcite over a wide pH interval, although it is less effective than HEDTA at pH &gt; 5. A unique property of GLDA is its high solubility; solutions exceeding 40 wt% can be achieved at a pH of approximately 2, whereas HEDTA solubility is limited to approximately 10 wt%. A mole of GLDA with a natural pH of approximately 1.5 is capable of dissolving up to two moles of CaCO3. Throughout the pH range, GLDA appears to be as thermally stable as HEDTA.As an additive to hydrochloric acid (HCl), GLDA is as effective as HEDTA in preventing precipitation of moderate levels of Fe3+ in spent acids. At high Fe3+ concentrations, GLDA is slightly less effective than HEDTA on a molar basis; but, to deal with high Fe3+ levels, GLDA may be better because significantly higher concentrations of it are possible in various acids. In 28 wt% HCl, HEDTA has limited solubility while GLDA's solubility exceeds 40 wt%.From an environmental standpoint, GLDA is readily biodegradable and is made from a renewable raw material, monosodium glutamate. GLDA has low toxicity and aquatic toxicity characteristics. As a replacement for HCl, GLDA is significantly safer and less corrosive.
Improved Kick Management During MPD by Real-Time Pore-Pressure Estimation
Authors: Gravdal Jan Einar , Nikolaou Michael , Breyholtz Øyvind , Carlsen Liv A. 
Published: September 2010

Summary
Pressure maintenance within safe bounds and minimization of influx of fluids from the formation to the well during a kick are basic concerns of well control. Managed-pressure drilling (MPD) offers improved capabilities over conventional well control methods to address these concerns. In this work, we develop a methodology that capitalizes on the improved access to downhole measurements offered by wired-drillpipe telemetry to maintain pressure within desired bounds during kick management. The objective of this methodology is to improve MPD by reducing nonproductive time, reducing formation damage, and optimizing operational limits for the annular backpressure choke manifold.
The proposed methodology estimates formation pore pressure automatically on the basis of real-time measurements when a gas kick is taken during MPD. The methodology relies on the characteristics of the pressure-buildup curve. Implementation of the methodology presumes the availability of standard MPD equipment for automatic annular backpressure control.
A representative North Sea well is used as test-case geometry, and an advanced hydraulics model is used as a virtual well in computer simulations that provide the basis for the presented results.
The proposed methodology is demonstrated to both maintain pressure within desirable bounds and reduce formation-fluid influx during a kick and thereby reduce the risk of hole-stability problems and the cost associated with nonproductive time.
Wellbore-Instability Predictions Within the Cretaceous Mudstones, Clair Field, West of Shetlands
Authors: Narayanasamy R.. , Barr D.. , Milne A.. 
Published: September 2010

Summary
Some early high-inclination wells were impacted adversely by wellbore instability within Cretaceous mudstones overlying the Clair oil field. Detailed investigations of the possible reasons for borehole failure led to a decision to cut two cores within the unstable interval and carry out laboratory testing to investigate the failure mechanism. Analysis of rock failure based on a "planes of weakness" theory fitted previous drilling observations. This theory has been applied primarily for layered hard rocks (e.g., mining and tunneling) and is here extended to significantly weaker mudstones showing strength anisotropy. Minimum required mud weight predictions were made for a range of well configurations. The results of this study were used to plan an extended-reach-drilling (ERD) development well targeting a previously undeveloped part of the Clair field. The new well was successfully drilled, cased, and brought on stream within budget in 2009.
This paper describes the basic geology of the field, rock properties of the Cretaceous mudstones, details of laboratory tests conducted, and analyses carried out. Cretaceous mudstones of the Clair field are characterized by low strength and minor anisotropy. Various rock tests were conducted on core to define the failure behavior: unconfined compressive strength (UCS), single-stage triaxial strength, and multistage triaxial strength tests were conducted, all at various angles to bedding. In addition, the effect of mud invasion was analyzed by performing a multistage triaxial test in drilling mud at high pressure. The analysis used commercial software to evaluate borehole instability in a rock medium that fails along weak planes. Minimum mud weight requirements derived from this analysis were compared with previous drilling experience and were used subsequently for predicting mud weight required to drill an ERD well. Lessons learned from the successful drilling of this well will be applied in future Clair development wells and may be of relevance elsewhere.
Reservoir Modeling in Shale-Gas Reservoirs
Authors: Cipolla C.L.. L. , Lolon E.P. P , Erdle J.C.. C. , Rubin B.. 
Published: September 2010

Summary
The exploitation of unconventional gas reservoirs has become an ever increasing component of the North American gas supply. The economic viability of many unconventional gas developments hinges on effective stimulation of extremely low-permeability rock by creating very complex fracture networks that connect huge reservoir surface area to the wellbore. In addition, gas desorption may be a significant component of overall gas recovery in many shale-gas reservoirs. The widespread application of microseismic (MS) mapping has significantly improved our understanding of hydraulic fracture growth in unconventional gas reservoirs (primarily shale) and has led to better stimulation designs. However, the overall effectiveness of stimulation treatments is difficult to determine from MS mapping because the location of proppant and the distribution of conductivity in the fracture network cannot be measured (and are critical parameters that control well performance). Therefore, it is important to develop reservoir-modeling approaches that properly characterize fluid flow in and the properties of a complex fracture network, tight matrix, and primary hydraulic fracture (if present) to evaluate well performance and understand critical parameters that affect gas recovery.
This paper illustrates the impact of gas desorption on production profile and ultimate gas recovery in shale reservoirs, showing that in some shale-gas reservoirs desorption may be a minor component of gas recovery. In addition, the paper details the impact of changing closure stress distribution in the fracture network on well productivity and gas recovery. In shale-gas reservoirs with lower Young's modulus rock, stress-dependent network-fracture conductivity may reduce ultimate gas recovery significantly. The paper includes an example that contrasts the application of numerical reservoir simulation and advanced decline-curve analyses to illustrate issues associated with conventional production-data-analysis techniques when applied to unconventional reservoirs.
Selected examples from the Barnett shale are included that incorporate MS fracture mapping and production data to illustrate the application of production modeling to evaluate well performance in unconventional gas reservoirs. This paper highlights production modeling and analysis techniques that aid in evaluating stimulation and completion strategies in unconventional gas reservoirs.
On the Wellbore Stress Change Caused by Drawdown and Depletion: An Analytical Model for a Vertical Well in a Thin Reservoir
Authors: Schutjens Peter , Kuvshinov Boris N. 
Published: September 2010

Summary
An analytical model is presented to describe the stress change at the wall of a vertical wellbore because of drawdown and reservoir depletion. The model predicts a lower effective tangential stress and higher effective axial stress (at a given drawdown) than the popular model of Risnes, Bratli, and Horsrud (RBH) model (Risnes et al. 1982; Bratli et al. 1983; Fjær et al. 2008). The reason for this difference is that our model is valid for a finite reservoir thickness ("thin reservoir"), whereas the RBH model is constrained by the condition of an infinite reservoir thickness.
We modeled the production-induced stress change in two reservoirs with different rock properties: Reservoir A has a porosity of approximately 20% and a permeability of up to 30 md; Reservoir B has a porosity of approximately 30% and a permeability of a few darcies. Calculated wellbore stress paths were combined with mechanical properties from core deformation experiments to evaluate the risk of drawdown-induced/depletion-induced shear failure. If we consider only the experimental shear-failure data collected on samples from Reservoir A for the shear-failure limit, then, according to the present model, the planned drawdown of 34 MPa will not lead to wellbore shear failure. Even after 34 MPa of depletion, a drawdown of 34 MPa can be applied safely in Reservoir A. For high-permeability Reservoir B, the model predicts that shear failure of the borehole wall will not occur in the first phase of production, when there is only a drawdown of up to 2 MPa and no depletion. Depending on the shear-failure criterion chosen, the model predicts shear failure after 25 to 42 MPa of depletion. Massive sand production was observed only after some 40 MPa of depletion, confirming that elastic-brittle models are conservative in predicting drawdown-induced or depletion-induced shear failure in a borehole, notably in high-porosity rocks. Our examples show their value in qualitative comparative analysis of shear failure and sand-production risk.
Numerical Evaluation of Hydrocarbon Additives to Steam in the SAGD Process
Authors: Mohebati Moslem Hosseininejad , Maini Brij B. , Harding Thomas G. 
Published: September 2010

Summary
Heavy oil and bitumen are expected to become increasingly important sources of fuel in the coming decades. Steam assisted gravity drainage (SAGD) is a commercially viable and widely used recovery technique for heavy oil and bitumen. However, it remains an expensive technique and requires large energy input in the form of steam. Energy intensity of SAGD, as well as environmental concerns such as fresh water usage and CO2 emission, make it imperative to find new oil extraction technologies. Coinjecting a hydrocarbon additive with steam offers the potential of higher oil rates and recoveries with lower energy and water consumption.
A reservoir simulation study using a 20X12X15 3D Cartesian model and Athabasca fluid and reservoir properties was conducted to evaluate this process. The role of hydrocarbon additive in the steam chamber and its effect on the performance of SAGD was investigated.
Simulation results revealed the parameters that will have the greatest impact on the process performance and indicated the effectiveness of each hydrocarbon additive in improving the performance of SAGD. The results also showed that selecting the most suitable hydrocarbon additive depends on the operating conditions as well as the original reservoir fluid composition.
Investigation of Cyclic Solvent Injection Process for Heavy Oil Recovery
Authors: Ivory John , Chang Jeannine , Coates Roy , Forshner Ken 
Published: September 2010

Summary
This paper summarizes numerical and experimental simulation results of a cyclic solvent injection process study, which was part of a continuing investigation into the use of solvents as a follow-up process in Cold Lake and Lloydminster reservoirs that have been pressure-depleted by cold heavy oil production with sand (CHOPS). Typically only 5% - 10% of the original oil in place (OOIP) is recovered during cold production; therefore, an effective follow-up process is required.
The cyclic solvent injection (CSI) experiment consisted of primary production followed by six solvent (28% C3H8 - 72% CO2) injection cycles. Oil recovery after primary production and six solvent cycles was 50%, which indicates the potential viability of the CSI process.
Concurrently with the laboratory physical simulation, a numerical simulation model was developed to represent the physical behaviour of the experimental results. A history match of the primary production portion of the experiment was obtained using an Alberta Innovates - Technology Futures (AITF) foamy oil model. This resulted in the characterization (fluid saturations and pressures) of the oil sandpack at the start of the solvent injection process. The history match of the subsequent six solvent injection cycles was used to validate the numerical model of the CSI process developed at AITF.
This model includes nonequilibrium rate equations that simulated the delay in solvent reaching its equilibrium concentration as it dissolves or exsolves in the oil in response to changes in the pressure and/or gas-phase composition. Dissolution of CH4, C3H8 and CO2 in oil and CO2 in water were considered, as was exsolution of CH4, C3H8 and CO2 from oil and CO2 from water. Reduced gas-phase permeabilities resulting from gas exsolution were also included.
The history match simulations indicated that:
The important mechanisms were represented in the simulations.
Significant oil swelling by solvent dissolution occurs during solvent injection periods. This can reduce solvent injectivity and penetration into a heavy oil reservoir during solvent injection periods.
Low oil and gas-phase relative permeabilities are required during production periods to match the experimental oil and gas production during solvent cycles.
A parametric simulation study showed that the quantity of gas injected in an injection period was relatively insensitive to the oil-phase diffusion coefficients, but was sensitive to solvent solubility in oil, dissolution rates, gas-phase diffusion coefficients, molar densities in the oil phase, gas-phase relative permeability and capillary pressure. It was shown that oil production is highly dependent on how quickly solvent can dissolve in the oil during injection and exsolve from the oil during production.
Naloxone, but Not Valsartan, Preserves Responses to Hypoglycemia After Antecedent Hypoglycemia
Authors: Poplawski Michal M. , Mastaitis Jason W. , Mobbs Charles V. 
Published: September 2010

OBJECTIVEHypoglycemia-associated autonomic failure (HAAF) constitutes one of the main clinical obstacles to optimum treatment of type 1 diabetes. Neurons in the ventromedial hypothalamus are thought to mediate counterregulatory responses to hypoglycemia. We have previously hypothesized that hypoglycemia-induced hypothalamic angiotensin might contribute to HAAF, suggesting that the angiotensin blocker valsartan might prevent HAAF. On the other hand, clinical studies have demonstrated that the opioid receptor blocker naloxone ameliorates HAAF. The goal of this study was to generate novel hypothalamic markers of hypoglycemia and use them to assess mechanisms mediating HAAF and its reversal.RESEARCH DESIGN AND METHODSQuantitative PCR was used to validate a novel panel of hypothalamic genes regulated by hypoglycemia. Mice were exposed to one or five episodes of insulin-induced hypoglycemia, with or without concurrent exposure to valsartan or naloxone. Corticosterone, glucagon, epinephrine, and hypothalamic gene expression were assessed after the final episode of hypoglycemia.RESULTSA subset of hypothalamic genes regulated acutely by hypoglycemia failed to respond after repetitive hypoglycemia. Responsiveness of a subset of these genes was preserved by naloxone but not valsartan. Notably, hypothalamic expression of four genes, including pyruvate dehydrogenase kinase 4 and glycerol 3-phosphate dehydrogenase 1, was acutely induced by a single episode of hypoglycemia, but not after antecedent hypoglycemia; naloxone treatment prevented this failure. Similarly, carnitine palmitoyltransferase-1 was inhibited after repetitive hypoglycemia, and this inhibition was prevented by naloxone. Repetitive hypoglycemia also caused a loss of hypoglycemia-induced elevation of glucocorticoid secretion, a failure prevented by naloxone but not valsartan.CONCLUSIONSBased on these observations we speculate that acute hypoglycemia induces reprogramming of hypothalamic metabolism away from glycolysis toward β-oxidation, HAAF is associated with a reversal of this reprogramming, and naloxone preserves some responses to hypoglycemia by preventing this reversal.