Co-optimization of CO 2 -EOR and Storage Processes under Geological Uncertainty

DOE PAGES

Ampomah, William; Balch, Robert; Will, Robert; ...

2017-07-01

This paper presents an integrated numerical framework to co-optimize EOR and CO 2 storage performance in the Farnsworth field unit (FWU), Ochiltree County, Texas. The framework includes a field-scale compositional reservoir flow model, an uncertainty quantification model and a neural network optimization process. The reservoir flow model has been constructed based on the field geophysical, geological, and engineering data. A laboratory fluid analysis was tuned to an equation of state and subsequently used to predict the thermodynamic minimum miscible pressure (MMP). A history match of primary and secondary recovery processes was conducted to estimate the reservoir and multiphase flow parametersmore » as the baseline case for analyzing the effect of recycling produced gas, infill drilling and water alternating gas (WAG) cycles on oil recovery and CO 2 storage. A multi-objective optimization model was defined for maximizing both oil recovery and CO 2 storage. The uncertainty quantification model comprising the Latin Hypercube sampling, Monte Carlo simulation, and sensitivity analysis, was used to study the effects of uncertain variables on the defined objective functions. Uncertain variables such as bottom hole injection pressure, WAG cycle, injection and production group rates, and gas-oil ratio among others were selected. The most significant variables were selected as control variables to be used for the optimization process. A neural network optimization algorithm was utilized to optimize the objective function both with and without geological uncertainty. The vertical permeability anisotropy (Kv/Kh) was selected as one of the uncertain parameters in the optimization process. The simulation results were compared to a scenario baseline case that predicted CO 2 storage of 74%. The results showed an improved approach for optimizing oil recovery and CO 2 storage in the FWU. The optimization process predicted more than 94% of CO 2 storage and most importantly about 28% of incremental oil recovery. The sensitivity analysis reduced the number of control variables to decrease computational time. A risk aversion factor was used to represent results at various confidence levels to assist management in the decision-making process. The defined objective functions were proved to be a robust approach to co-optimize oil recovery and CO 2 storage. The Farnsworth CO 2 project will serve as a benchmark for future CO 2–EOR or CCUS projects in the Anadarko basin or geologically similar basins throughout the world.« less

Geologic input to enhanced oil recovery project planning in south Oman

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watts, N.L.; Ellis, D.; Heward, A.P.

1986-05-01

South Oman clastic reservoirs contain a combined stock-tank oil in place of more than 1.9 billion m/sup 3/ of predominantly heavy oil distributed in almost 40 fields of varying size. Successful early application of such enhanced oil recovery (EOR) methods as steam flood, polymer drive, and steam soak could realize undiscounted incremental recoveries of 244 million m/sup 3/ of oil. Target oil is contained in three reservoir intervals with distinct characteristics relevant to EOR. (1) The Cambrian-Ordovician Haima Group is a thick monotonous sequence of continental and coastal sands; major problems are steam-rock reactions, recovery factors, effective kv/kh (ratio ofmore » vertical to horizontal permeability), and aquifer strength. (2) The Permian-Carboniferous Al Khlata Formation is a glacial package showing severe heterogeneity, strong permeability anisotropy, and poor predictability. (3) The Permian Gharif Formation is a coastal to fluvial sequence with isolated and multilayer channel sands, smectitic clays, and anomalous primary production performance. Several EOR pilot projects are either ongoing or in preparation as part of a longer term EOR strategy. Geologic input is important at four essential stages of pilot planning: initial project ranking, optimization of pilot location, definition of pilot size, and predictive/history match simulations. Each stage is illustrated using a specific project example from south Oman to show the diverse geologic and logistic problems of the area. Although geologic aspects are highlighted, EOR project planning in south Oman is multidisciplinary, with integration being aided by a dedicated EOR coordination department.« less

Viscous and gravitational fingering in multiphase compositional and compressible flow

NASA Astrophysics Data System (ADS)

Moortgat, Joachim

2016-03-01

Viscous and gravitational fingering refer to flow instabilities in porous media that are triggered by adverse mobility or density ratios, respectively. These instabilities have been studied extensively in the past for (1) single-phase flow (e.g., contaminant transport in groundwater, first-contact-miscible displacement of oil by gas in hydrocarbon production), and (2) multi-phase immiscible and incompressible flow (e.g., water-alternating-gas (WAG) injection in oil reservoirs). Fingering in multiphase compositional and compressible flow has received much less attention, perhaps due to its high computational complexity. However, many important subsurface processes involve multiple phases that exchange species. Examples are carbon sequestration in saline aquifers and enhanced oil recovery (EOR) by gas or WAG injection below the minimum miscibility pressure. In multiphase flow, relative permeabilities affect the mobility contrast for a given viscosity ratio. Phase behavior can also change local fluid properties, which can either enhance or mitigate viscous and gravitational instabilities. This work presents a detailed study of fingering behavior in compositional multiphase flow in two and three dimensions and considers the effects of (1) Fickian diffusion, (2) mechanical dispersion, (3) flow rates, (4) domain size and geometry, (5) formation heterogeneities, (6) gravity, and (7) relative permeabilities. Results show that fingering in compositional multiphase flow is profoundly different from miscible conditions and upscaling techniques used for the latter case are unlikely to be generalizable to the former.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gragg, Evan James; Middleton, Richard Stephen

This report describes the benefits of the BECCUS screening tools. The goals of this project are to utilize NATCARB database for site screening; enhance NATCARB database; run CO 2-EOR simulations and economic models using updated reservoir data sets (SCO 2T-EOR).

DEVELOPMENT AND OPTIMIZATION OF GAS-ASSISTED GRAVITY DRAINAGE (GAGD) PROCESS FOR IMPROVED LIGHT OIL RECOVERY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dandina N. Rao; Subhash C. Ayirala; Madhav M. Kulkarni

This report describes the progress of the project ''Development and Optimization of Gas-Assisted Gravity Drainage (GAGD) Process for Improved Light Oil Recovery'' for the duration of the second project year (October 1, 2003--September 30, 2004). There are three main tasks in this research project. Task 1 is scaled physical model study of GAGD process. Task 2 is further development of vanishing interfacial tension (VIT) technique for miscibility determination. Task 3 is determination of multiphase displacement characteristics in reservoir rocks. In Section I, preliminary design of the scaled physical model using the dimensional similarity approach has been presented. Scaled experiments onmore » the current physical model have been designed to investigate the effect of Bond and capillary numbers on GAGD oil recovery. Experimental plan to study the effect of spreading coefficient and reservoir heterogeneity has been presented. Results from the GAGD experiments to study the effect of operating mode, Bond number and capillary number on GAGD oil recovery have been reported. These experiments suggest that the type of the gas does not affect the performance of GAGD in immiscible mode. The cumulative oil recovery has been observed to vary exponentially with Bond and capillary numbers, for the experiments presented in this report. A predictive model using the bundle of capillary tube approach has been developed to predict the performance of free gravity drainage process. In Section II, a mechanistic Parachor model has been proposed for improved prediction of IFT as well as to characterize the mass transfer effects for miscibility development in reservoir crude oil-solvent systems. Sensitivity studies on model results indicate that provision of a single IFT measurement in the proposed model is sufficient for reasonable IFT predictions. An attempt has been made to correlate the exponent (n) in the mechanistic model with normalized solute compositions present in both fluid phases. IFT measurements were carried out in a standard ternary liquid system of benzene, ethanol and water using drop shape analysis and capillary rise techniques. The experimental results indicate strong correlation among the three thermodynamic properties solubility, miscibility and IFT. The miscibility determined from IFT measurements for this ternary liquid system is in good agreement with phase diagram and solubility data, which clearly indicates the sound conceptual basis of VIT technique to determine fluid-fluid miscibility. Model fluid systems have been identified for VIT experimentation at elevated pressures and temperatures. Section III comprises of the experimental study aimed at evaluating the multiphase displacement characteristics of the various gas injection EOR process performances using Berea sandstone cores. During this reporting period, extensive literature review was completed to: (1) study the gravity drainage concepts, (2) identify the various factors influencing gravity stable gas injection processes, (3) identify various multiphase mechanisms and fluid dynamics operative during the GAGD process, and (4) identify important dimensionless groups governing the GAGD process performance. Furthermore, the dimensional analysis of the GAGD process, using Buckingham-Pi theorem to isolate the various dimensionless groups, as well as experimental design based on these dimensionless quantities have been completed in this reporting period. On the experimental front, recommendations from previous WAG and CGI have been used to modify the experimental protocol. This report also includes results from scaled preliminary GAGD displacements as well as the details of the planned GAGD corefloods for the next quarter. The technology transfer activities have mainly consisted of preparing technical papers, progress reports and discussions with industry personnel for possible GAGD field tests.« less

Development and Optimization of Gas-Assisted Gravity Drainage (GAGD) Process for Improved Light Oil Recovery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dandina N. Rao; Subhash C. Ayirala; Madhav M. Kulkarni

This is the final report describing the evolution of the project ''Development and Optimization of Gas-Assisted Gravity Drainage (GAGD) Process for Improved Light Oil Recovery'' from its conceptual stage in 2002 to the field implementation of the developed technology in 2006. This comprehensive report includes all the experimental research, models developments, analyses of results, salient conclusions and the technology transfer efforts. As planned in the original proposal, the project has been conducted in three separate and concurrent tasks: Task 1 involved a physical model study of the new GAGD process, Task 2 was aimed at further developing the vanishing interfacialmore » tension (VIT) technique for gas-oil miscibility determination, and Task 3 was directed at determining multiphase gas-oil drainage and displacement characteristics in reservoir rocks at realistic pressures and temperatures. The project started with the task of recruiting well-qualified graduate research assistants. After collecting and reviewing the literature on different aspects of the project such gas injection EOR, gravity drainage, miscibility characterization, and gas-oil displacement characteristics in porous media, research plans were developed for the experimental work to be conducted under each of the three tasks. Based on the literature review and dimensional analysis, preliminary criteria were developed for the design of the partially-scaled physical model. Additionally, the need for a separate transparent model for visual observation and verification of the displacement and drainage behavior under gas-assisted gravity drainage was identified. Various materials and methods (ceramic porous material, Stucco, Portland cement, sintered glass beads) were attempted in order to fabricate a satisfactory visual model. In addition to proving the effectiveness of the GAGD process (through measured oil recoveries in the range of 65 to 87% IOIP), the visual models demonstrated three possible multiphase mechanisms at work, namely, Darcy-type displacement until gas breakthrough, gravity drainage after breakthrough and film-drainage in gas-invaded zones throughout the duration of the process. The partially-scaled physical model was used in a series of experiments to study the effects of wettability, gas-oil miscibility, secondary versus tertiary mode gas injection, and the presence of fractures on GAGD oil recovery. In addition to yielding recoveries of up to 80% IOIP, even in the immiscible gas injection mode, the partially-scaled physical model confirmed the positive influence of fractures and oil-wet characteristics in enhancing oil recoveries over those measured in the homogeneous (unfractured) water-wet models. An interesting observation was that a single logarithmic relationship between the oil recovery and the gravity number was obeyed by the physical model, the high-pressure corefloods and the field data.« less

Integrated Reservoir Modeling of CO2-EOR Performance and Storage Potential in the Farnsworth Field Unit, Texas.

NASA Astrophysics Data System (ADS)

Ampomah, W.; Balch, R. S.; Cather, M.; Dai, Z.

2017-12-01

We present a performance assessment methodology and storage potential for CO2 enhanced oil recovery (EOR) in partially depleted reservoirs. A three dimensional heterogeneous reservoir model was developed based on geological, geophysics and engineering data from Farnsworth field Unit (FWU). The model aided in improved characterization of prominent rock properties within the Pennsylvanian aged Morrow sandstone reservoir. Seismic attributes illuminated previously unknown faults and structural elements within the field. A laboratory fluid analysis was tuned to an equation of state and subsequently used to predict the thermodynamic minimum miscible pressure (MMP). Datasets including net-to-gross ratio, volume of shale, permeability, and burial history were used to model initial fault transmissibility based on Sperivick model. An improved history match of primary and secondary recovery was performed to set the basis for a CO2 flood study. The performance of the current CO2 miscible flood patterns was subsequently calibrated to historical production and injection data. Several prediction models were constructed to study the effect of recycling, addition of wells and /or new patterns, water alternating gas (WAG) cycles and optimum amount of CO2 purchase on incremental oil production and CO2 storage in the FWU. The history matching study successfully validated the presence of the previously undetected faults within FWU that were seen in the seismic survey. The analysis of the various prediction scenarios showed that recycling a high percentage of produced gas, addition of new wells and a gradual reduction in CO2 purchase after several years of operation would be the best approach to ensure a high percentage of recoverable incremental oil and sequestration of anthropogenic CO2 within the Morrow reservoir. Larger percentage of stored CO2 were dissolved in residual oil and less amount existed as supercritical free CO2. The geomechanical analysis on the caprock proved to an excellent seal to ensure long-term security of injected CO2.

Control of Viscous Fingering in Miscible Displacements in Porous Media with a Periodic Change of Injection Rate

NASA Astrophysics Data System (ADS)

Yuan, Q.; Zeng, F.; Knorr, K. D.; Imran, M.

2017-12-01

Context/PurposeThe viscous fingering (VF) is widely encountered in a series of miscible displacements such as CO2 sequestration and solvent-based enhanced oil recovery (EOR). Accurate prediction and effective control of its development are significant. Commercial simulators cannot capture VF because of large numerical diffusion. Moreover, previous measures for controlling VF using polymer are very expensive. In the present study, a periodic change of injection rate involving injection and extraction is used to control and reduce VF instabilities at zero cost. MethodsHighly accurate spectral method and fully implicit alternating direction implicit method are used to simulate VF with concentration-dependent diffusion (CDD) and velocity-induced dispersion (VID), although the consideration of CDD and VID may result in strong nonlinearity and stiff problem under unfavourable viscosity ratio. In-house code is developed. The VF is reduced by optimizing period and amplitude of injection rate. ResultsThe results show that the periodic change of injection rates can strongly affect VF and sweep efficiency. In particular, a period-stabilizing range is found in which the VF is reduced compared with widely used constant injection with the same amount of fluid injected. The frequent change of rate results in high sweep efficiency. The optimal injection scheme, when compared with constant injection, can improve sweep efficiency by 20-35%. InterpretationDispersion plays a key role in the mitigation of VF in periodic displacement rates. It enhances the uniform mixing of two fluids in injection stage in any period, while it can more effectively attenuate VF instabilities through the following extraction stage. Fast switch of injection and extraction can mitigate flow instability once it develops. ConclusionThis finding is very novel and significant as it is the first time to control VF instability in porous media without any additional cost. It shows great potential for EOR at zero cost.

Recovery rates, enhanced oil recovery and technological limits

PubMed Central

Muggeridge, Ann; Cockin, Andrew; Webb, Kevin; Frampton, Harry; Collins, Ian; Moulds, Tim; Salino, Peter

2014-01-01

Enhanced oil recovery (EOR) techniques can significantly extend global oil reserves once oil prices are high enough to make these techniques economic. Given a broad consensus that we have entered a period of supply constraints, operators can at last plan on the assumption that the oil price is likely to remain relatively high. This, coupled with the realization that new giant fields are becoming increasingly difficult to find, is creating the conditions for extensive deployment of EOR. This paper provides a comprehensive overview of the nature, status and prospects for EOR technologies. It explains why the average oil recovery factor worldwide is only between 20% and 40%, describes the factors that contribute to these low recoveries and indicates which of those factors EOR techniques can affect. The paper then summarizes the breadth of EOR processes, the history of their application and their current status. It introduces two new EOR technologies that are beginning to be deployed and which look set to enter mainstream application. Examples of existing EOR projects in the mature oil province of the North Sea are discussed. It concludes by summarizing the future opportunities for the development and deployment of EOR. PMID:24298076

Recovery rates, enhanced oil recovery and technological limits.

PubMed

Muggeridge, Ann; Cockin, Andrew; Webb, Kevin; Frampton, Harry; Collins, Ian; Moulds, Tim; Salino, Peter

2014-01-13

Enhanced oil recovery (EOR) techniques can significantly extend global oil reserves once oil prices are high enough to make these techniques economic. Given a broad consensus that we have entered a period of supply constraints, operators can at last plan on the assumption that the oil price is likely to remain relatively high. This, coupled with the realization that new giant fields are becoming increasingly difficult to find, is creating the conditions for extensive deployment of EOR. This paper provides a comprehensive overview of the nature, status and prospects for EOR technologies. It explains why the average oil recovery factor worldwide is only between 20% and 40%, describes the factors that contribute to these low recoveries and indicates which of those factors EOR techniques can affect. The paper then summarizes the breadth of EOR processes, the history of their application and their current status. It introduces two new EOR technologies that are beginning to be deployed and which look set to enter mainstream application. Examples of existing EOR projects in the mature oil province of the North Sea are discussed. It concludes by summarizing the future opportunities for the development and deployment of EOR.

A Full-Featured User Friendly CO 2-EOR and Sequestration Planning Software

DOE Office of Scientific and Technical Information (OSTI.GOV)

Savage, Bill

A Full-Featured, User Friendly CO 2-EOR and Sequestration Planning Software This project addressed the development of an integrated software solution that includes a graphical user interface, numerical simulation, visualization tools and optimization processes for reservoir simulation modeling of CO 2-EOR. The objective was to assist the industry in the development of domestic energy resources by expanding the application of CO 2-EOR technologies, and ultimately to maximize the CO 2} sequestration capacity of the U.S. The software resulted in a field-ready application for the industry to address the current CO 2-EOR technologies. The software has been made available to the publicmore » without restrictions and with user friendly operating documentation and tutorials. The software (executable only) can be downloaded from NITEC’s website at www.nitecllc.com. This integrated solution enables the design, optimization and operation of CO 2-EOR processes for small and mid-sized operators, who currently cannot afford the expensive, time intensive solutions that the major oil companies enjoy. Based on one estimate, small oil fields comprise 30% of the of total economic resource potential for the application of CO 2-EOR processes in the U.S. This corresponds to 21.7 billion barrels of incremental, technically recoverable oil using the current “best practices”, and 31.9 billion barrels using “next-generation” CO 2-EOR techniques. The project included a Case Study of a prospective CO 2-EOR candidate field in Wyoming by a small independent, Linc Energy Petroleum Wyoming, Inc. NITEC LLC has an established track record of developing innovative and user friendly software. The Principle Investigator is an experienced manager and engineer with expertise in software development, numerical techniques, and GUI applications. Unique, presently-proprietary NITEC technologies have been integrated into this application to further its ease of use and technical functionality.« less

Current Status of the LOFAR EoR Key Science Project

NASA Astrophysics Data System (ADS)

Koopmans, L. V. E.; LOFAR EoR KSP Team

2018-05-01

A short status update on the LOFAR Epoch of Reionization (EoR) Key Science Project (KSP) is given, regarding data acquisition, data processing and analysis, and current power-spectrum limits on the redshifted 21-cm signal of neutral hydrogen at redshifts z = 8 - 10. With caution, we present a preliminary astrophysical analysis of ~60 hr of processed LOFAR data and their resulting power spectrum, showing that potentially already interesting limits on X-ray heating during the Cosmic Dawn can already be gained. This is by no means the final analysis of this sub-set of data, but illustrates the future potential when all nearly 3000 hr of data in hand on two EoR windows will have been processed.

Can Producing Oil Store Carbon? Greenhouse Gas Footprint of CO2EOR, Offshore North Sea.

PubMed

Stewart, R Jamie; Haszeldine, R Stuart

2015-05-05

Carbon dioxide enhanced oil recovery (CO2EOR) is a proven and available technology used to produce incremental oil from depleted fields while permanently storing large tonnages of injected CO2. Although this technology has been used successfully onshore in North America and Europe, there are currently no CO2EOR projects in the United Kingdom. Here, we examine whether offshore CO2EOR can store more CO2 than onshore projects traditionally have and whether CO2 storage can offset additional emissions produced through offshore operations and incremental oil production. Using a high-level Life Cycle system approach, we find that the largest contribution to offshore emissions is from flaring or venting of reproduced CH4 and CO2. These can already be greatly reduced by regulation. If CO2 injection is continued after oil production has been optimized, then offshore CO2EOR has the potential to be carbon negative--even when emissions from refining, transport, and combustion of produced crude oil are included. The carbon intensity of oil produced can be just 0.056-0.062 tCO2e/bbl if flaring/venting is reduced by regulation. This compares against conventional Saudi oil 0.040 tCO2e/bbl or mined shale oil >0.300 tCO2e/bbl.

Managing geological uncertainty in CO2-EOR reservoir assessments

NASA Astrophysics Data System (ADS)

Welkenhuysen, Kris; Piessens, Kris

2014-05-01

Recently the European Parliament has agreed that an atlas for the storage potential of CO2 is of high importance to have a successful commercial introduction of CCS (CO2 capture and geological storage) technology in Europe. CO2-enhanced oil recovery (CO2-EOR) is often proposed as a promising business case for CCS, and likely has a high potential in the North Sea region. Traditional economic assessments for CO2-EOR largely neglect the geological reality of reservoir uncertainties because these are difficult to introduce realistically in such calculations. There is indeed a gap between the outcome of a reservoir simulation and the input values for e.g. cost-benefit evaluations, especially where it concerns uncertainty. The approach outlined here is to turn the procedure around, and to start from which geological data is typically (or minimally) requested for an economic assessment. Thereafter it is evaluated how this data can realistically be provided by geologists and reservoir engineers. For the storage of CO2 these parameters are total and yearly CO2 injection capacity, and containment or potential on leakage. Specifically for the EOR operation, two additional parameters can be defined: the EOR ratio, or the ratio of recovered oil over injected CO2, and the CO2 recycling ratio of CO2 that is reproduced after breakthrough at the production well. A critical but typically estimated parameter for CO2-EOR projects is the EOR ratio, taken in this brief outline as an example. The EOR ratio depends mainly on local geology (e.g. injection per well), field design (e.g. number of wells), and time. Costs related to engineering can be estimated fairly good, given some uncertainty range. The problem is usually to reliably estimate the geological parameters that define the EOR ratio. Reliable data is only available from (onshore) CO2-EOR projects in the US. Published studies for the North Sea generally refer to these data in a simplified form, without uncertainty ranges, and are therefore not suited for cost-benefit analysis. They likely result in too optimistic results because onshore configurations are cheaper and different. We propose to translate the detailed US data to the North Sea, retaining their uncertainty ranges. In a first step, a general cost correction can be applied to account for costs specific to the EU and the offshore setting. In a second step site-specific data, including laboratory tests and reservoir modelling, are used to further adapt the EOR ratio values taking into account all available geological reservoir-specific knowledge. And lastly, an evaluation of the field configuration will have an influence on both the cost and local geology dimension, because e.g. horizontal drilling is needed (cost) to improve injectivity (geology). As such, a dataset of the EOR field is obtained which contains all aspects and their uncertainty ranges. With these, a geologically realistic basis is obtained for further cost-benefit analysis of a specific field, where the uncertainties are accounted for using a stochastic evaluation. Such ad-hoc evaluation of geological parameters will provide a better assessment of the CO2-EOR potential of the North Sea oil fields.

Post Waterflood CO2 Miscible Flood in Light Oil, Fluvial-Dominated Deltaic Reservoir (Pre-Work and Project Proposal), Class I

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bou-Mikael, Sami

This project outlines a proposal to improve the recovery of light oil from waterflooded fluvial dominated deltaic (FDD) reservoir through a miscible carbon dioxide (CO2) flood. The site is the Port Neches Field in Orange County, Texas. The field is well explored and well exploited. The project area is 270 acres within the Port Neches Field.

International Energy Agency (IEA) Greenhouse Gas (GHG) Weyburn-Midale CO₂ Monitoring and Storage Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sacuta, Norm; Young, Aleana; Worth, Kyle

2015-12-22

The IEAGHG Weyburn-Midale CO₂ Monitoring and Storage Project (WMP) began in 2000 with the first four years of research that confirmed the suitability of the containment complex of the Weyburn oil field in southeastern Saskatchewan as a storage location for CO₂ injected as part of enhanced oil recovery (EOR) operations. The first half of this report covers research conducted from 2010 to 2012, under the funding of the United States Department of Energy (contract DEFE0002697), the Government of Canada, and various other governmental and industry sponsors. The work includes more in-depth analysis of various components of a measurement, monitoring andmore » verification (MMV) program through investigation of data on site characterization and geological integrity, wellbore integrity, storage monitoring (geophysical and geochemical), and performance/risk assessment. These results then led to the development of a Best Practices Manual (BPM) providing oilfield and project operators with guidance on CO₂ storage and CO₂-EOR. In 2013, the USDOE and Government of Saskatchewan exercised an optional phase of the same project to further develop and deploy applied research tools, technologies, and methodologies to the data and research at Weyburn with the aim of assisting regulators and operators in transitioning CO₂-EOR operations into permanent storage. This work, detailed in the second half of this report, involves seven targeted research projects – evaluating the minimum dataset for confirming secure storage; additional overburden monitoring; passive seismic monitoring; history-matched modelling; developing proper wellbore design; casing corrosion evaluation; and assessment of post CO₂-injected core samples. The results from the final and optional phases of the Weyburn-Midale Project confirm the suitability of CO₂-EOR fields for the injection of CO₂, and further, highlight the necessary MMV and follow-up monitoring required for these operations to be considered permanent storage.« less

An Analysis of the Distribution and Economics of Oil Fields for Enhanced Oil Recovery-Carbon Capture and Storage

NASA Astrophysics Data System (ADS)

Hall, Kristyn Ann

The rising carbon dioxide emissions contributing to climate change has lead to the examination of potential ways to mitigate the environmental impact. One such method is through the geological sequestration of carbon (CCS). Although there are several different forms of geological sequestration (i.e. Saline Aquifers, Oil and Gas Reservoirs, Unminable Coal Seams) the current projects are just initiating the large scale-testing phase. The lead entry point into CCS projects is to combine the sequestration with enhanced oil recovery (EOR) due to the improved economic model as a result of the oil recovery and the pre-existing knowledge of the geological structures. The potential scope of CCS-EOR projects throughout the continental United States in terms of a systematic examination of individual reservoir storage potential has not been examined. Instead the majority of the research completed has centered on either estimating the total United States storage potential or the potential of a single specific reservoir. The purpose of this paper is to examine the relationship between oil recovery, carbon dioxide storage and cost during CCS-EOR. The characteristics of the oil and gas reservoirs examined in this study from the Nehring Oil and Gas Database were used in the CCS-EOR model developed by Sean McCoy to estimate the lifting and storage costs of the different reservoirs throughout the continental United States. This allows for an examination of both technical and financial viability of CCS-EOR as an intermediate step for future CCS projects in other geological formations. One option for mitigating climate change is to store industrial CO2 emissions in geologic reservoirs as part of a process known as carbon capture and storage (CCS). There is general consensus that large-scale deployment of CCS would best be initiated by combining geologic sequestration with enhanced oil recovery (EOR), which can use CO2 to improve production from declining oil fields. Revenues from the produced oil could help offset the current high costs of CCS. The cumulative potential of CCS-EOR in the continental U.S. has been evaluated in terms of both CO2 storage capacity and additional oil production. This thesis examines the same potential, but on a reservoir-by-reservoir basis. Reservoir properties from the Nehring Oil and Gas Database are used as inputs to a CCS-EOR model developed by McCoy (YR) to estimate the storage capacity, oil production and CCS-EOR costs for over 10,000 oil reservoirs located throughout the continental United States. We find that 86% of the reservoirs could store ≤1 y or CO2 emissions from a single 500 MW coal-fired power plant (i.e., 3 Mtons CO2). Less than 1% of the reservoirs, on the other hand, appear capable of storing ≥30 y of CO2 emissions from a 500 MW plan. But these larger reservoirs are also estimated to contain 48% of the predicted additional oil that could be produced through CCS-EOR. The McCoy model also predicts that the reservoirs will on average produce 4.5 bbl of oil for each ton of sequestered CO2, a ratio known as the utilization factor. This utilization factor is 1.5 times higher that arrived at by the U.S. Department of Energy, and leads to a cumulative production of oil for all the reservoirs examined of ˜183 billion barrels along with a cumulative storage capacity of 41 Mtons CO2. This is equivalent to 26.5 y of current oil consumption by the nation, and 8.5 y of current coal plant emissions.

Joint inversion of time-lapse VSP data for monitoring CO2 injection at the Farnsworth EOR field in Texas

NASA Astrophysics Data System (ADS)

Zhang, M.; Gao, K.; Balch, R. S.; Huang, L.

2016-12-01

During the Development Phase (Phase III) of the U.S. Southwest Regional Partnership on Carbon Sequestration (SWP), time-lapse 3D vertical seismic profiling (VSP) data were acquired to monitor CO2 injection/migration at the Farnsworth Enhanced Oil Recovery (EOR) field, in partnership with the industrial partner Chaparral Energy. The project is to inject a million tons of carbon dioxide into the target formation, the deep oil-bearing Morrow Formation in the Farnsworth Unit EOR field. Quantitative time-lapse seismic monitoring has the potential to track CO2 movement in geologic carbon storage sites. Los Alamos National Laboratory (LANL) has recently developed new full-waveform inversion methods to jointly invert time-lapse seismic data for changes in elastic and anisotropic parameters in target monitoring regions such as a CO2 reservoir. We apply our new joint inversion methods to time-lapse VSP data acquired at the Farnsworth EOR filed, and present some preliminary results showing geophysical properties changes in the reservoir.

CONTROLLING THE AQUEOUS MISCIBILITY OF IONIC LIQUIDS: A NOVEL AQUEOUS BIPHASIC SYSTEM FROM WATER-MISCIBLE IONIC LIQUID AND A WATER-STRUCTURING SALT. (R828257)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Economics show CO2 EOR potential in central Kansas

USGS Publications Warehouse

Dubois, M.K.; Byrnes, A.P.; Pancake, R.E.; Willhite, G.P.; Schoeling, L.G.

2000-01-01

Carbon dioxide (CO2) enhanced oil recovery (EOR) may be the key to recovering hundreds of millions of bbl of trapped oil from the mature fields in central Kansas. Preliminary economic analysis indicates that CO2 EOR should provide an internal rate of return (IRR) greater than 20%, before income tax, assuming oil sells for \\$20/bbl, CO2 costs \\$1/Mcf, and gross utilization is 10 Mcf of CO2/bbl of oil recovered. If the CO2 cost is reduced to \\$0.75/Mcf, an oil price of $17/bbl yields an IRR of 20%. Reservoir and economic modeling indicates that IRR is most sensitive to oil price and CO2 cost. A project requires a minimum recovery of 1,500 net bbl/acre (about 1 million net bbl/1-mile section) under a best-case scenario. Less important variables to the economics are capital costs and non-CO2 related lease operating expenses.

A chemical EOR benchmark study of different reservoir simulators

NASA Astrophysics Data System (ADS)

Goudarzi, Ali; Delshad, Mojdeh; Sepehrnoori, Kamy

2016-09-01

Interest in chemical EOR processes has intensified in recent years due to the advancements in chemical formulations and injection techniques. Injecting Polymer (P), surfactant/polymer (SP), and alkaline/surfactant/polymer (ASP) are techniques for improving sweep and displacement efficiencies with the aim of improving oil production in both secondary and tertiary floods. There has been great interest in chemical flooding recently for different challenging situations. These include high temperature reservoirs, formations with extreme salinity and hardness, naturally fractured carbonates, and sandstone reservoirs with heavy and viscous crude oils. More oil reservoirs are reaching maturity where secondary polymer floods and tertiary surfactant methods have become increasingly important. This significance has added to the industry's interest in using reservoir simulators as tools for reservoir evaluation and management to minimize costs and increase the process efficiency. Reservoir simulators with special features are needed to represent coupled chemical and physical processes present in chemical EOR processes. The simulators need to be first validated against well controlled lab and pilot scale experiments to reliably predict the full field implementations. The available data from laboratory scale include 1) phase behavior and rheological data; and 2) results of secondary and tertiary coreflood experiments for P, SP, and ASP floods under reservoir conditions, i.e. chemical retentions, pressure drop, and oil recovery. Data collected from corefloods are used as benchmark tests comparing numerical reservoir simulators with chemical EOR modeling capabilities such as STARS of CMG, ECLIPSE-100 of Schlumberger, REVEAL of Petroleum Experts. The research UTCHEM simulator from The University of Texas at Austin is also included since it has been the benchmark for chemical flooding simulation for over 25 years. The results of this benchmark comparison will be utilized to improve chemical design for field-scale studies using commercial simulators. The benchmark tests illustrate the potential of commercial simulators for chemical flooding projects and provide a comprehensive table of strengths and limitations of each simulator for a given chemical EOR process. Mechanistic simulations of chemical EOR processes will provide predictive capability and can aid in optimization of the field injection projects. The objective of this paper is not to compare the computational efficiency and solution algorithms; it only focuses on the process modeling comparison.

Co-Optimization of CO 2-EOR and Storage Processes in Mature Oil Reservoirs

DOE PAGES

Ampomah, William; Balch, Robert S.; Grigg, Reid B.; ...

2016-08-02

This article presents an optimization methodology for CO 2 enhanced oil recovery in partially depleted reservoirs. A field-scale compositional reservoir flow model was developed for assessing the performance history of an active CO 2 flood and for optimizing both oil production and CO 2 storage in the Farnsworth Unit (FWU), Ochiltree County, Texas. A geological framework model constructed from geophysical, geological, and engineering data acquired from the FWU was the basis for all reservoir simulations and the optimization method. An equation of state was calibrated with laboratory fluid analyses and subsequently used to predict the thermodynamic minimum miscible pressure (MMP).more » Initial history calibrations of primary, secondary and tertiary recovery were conducted as the basis for the study. After a good match was achieved, an optimization approach consisting of a proxy or surrogate model was constructed with a polynomial response surface method (PRSM). The PRSM utilized an objective function that maximized both oil recovery and CO 2 storage. Experimental design was used to link uncertain parameters to the objective function. Control variables considered in this study included: water alternating gas cycle and ratio, production rates and bottom-hole pressure of injectors and producers. Other key parameters considered in the modeling process were CO 2 purchase, gas recycle and addition of infill wells and/or patterns. The PRSM proxy model was ‘trained’ or calibrated with a series of training simulations. This involved an iterative process until the surrogate model reached a specific validation criterion. A sensitivity analysis was first conducted to ascertain which of these control variables to retain in the surrogate model. A genetic algorithm with a mixed-integer capability optimization approach was employed to determine the optimum developmental strategy to maximize both oil recovery and CO 2 storage. The proxy model reduced the computational cost significantly. The validation criteria of the reduced order model ensured accuracy in the dynamic modeling results. The prediction outcome suggested robustness and reliability of the genetic algorithm for optimizing both oil recovery and CO 2 storage. The reservoir modeling approach used in this study illustrates an improved approach to optimizing oil production and CO 2 storage within partially depleted oil reservoirs such as FWU. Lastly, this study may serve as a benchmark for potential CO 2–EOR projects in the Anadarko basin and/or geologically similar basins throughout the world.« less

Co-Optimization of CO 2-EOR and Storage Processes in Mature Oil Reservoirs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ampomah, William; Balch, Robert S.; Grigg, Reid B.

This article presents an optimization methodology for CO 2 enhanced oil recovery in partially depleted reservoirs. A field-scale compositional reservoir flow model was developed for assessing the performance history of an active CO 2 flood and for optimizing both oil production and CO 2 storage in the Farnsworth Unit (FWU), Ochiltree County, Texas. A geological framework model constructed from geophysical, geological, and engineering data acquired from the FWU was the basis for all reservoir simulations and the optimization method. An equation of state was calibrated with laboratory fluid analyses and subsequently used to predict the thermodynamic minimum miscible pressure (MMP).more » Initial history calibrations of primary, secondary and tertiary recovery were conducted as the basis for the study. After a good match was achieved, an optimization approach consisting of a proxy or surrogate model was constructed with a polynomial response surface method (PRSM). The PRSM utilized an objective function that maximized both oil recovery and CO 2 storage. Experimental design was used to link uncertain parameters to the objective function. Control variables considered in this study included: water alternating gas cycle and ratio, production rates and bottom-hole pressure of injectors and producers. Other key parameters considered in the modeling process were CO 2 purchase, gas recycle and addition of infill wells and/or patterns. The PRSM proxy model was ‘trained’ or calibrated with a series of training simulations. This involved an iterative process until the surrogate model reached a specific validation criterion. A sensitivity analysis was first conducted to ascertain which of these control variables to retain in the surrogate model. A genetic algorithm with a mixed-integer capability optimization approach was employed to determine the optimum developmental strategy to maximize both oil recovery and CO 2 storage. The proxy model reduced the computational cost significantly. The validation criteria of the reduced order model ensured accuracy in the dynamic modeling results. The prediction outcome suggested robustness and reliability of the genetic algorithm for optimizing both oil recovery and CO 2 storage. The reservoir modeling approach used in this study illustrates an improved approach to optimizing oil production and CO 2 storage within partially depleted oil reservoirs such as FWU. Lastly, this study may serve as a benchmark for potential CO 2–EOR projects in the Anadarko basin and/or geologically similar basins throughout the world.« less

Case Studies of the ROZ CO 2 Flood and the Combined ROZ/MPZ CO 2 Flood at the Goldsmith Landreth Unit, Ector County, Texas. Using ''Next Generation'' CO 2 EOR Technologies to Optimize the Residual Oil Zone CO 2 Flood

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trentham, Robert C.; Melzer, L. Stephen; Kuuskraa, Vello

2015-06-30

The technology for CO 2 Enhanced Oil Recovery (CO 2 EOR) has significantly advanced since the earliest floods were implemented in the 1970s. At least for the Permian Basin region of the U.S., the oil recovery has been now been extended into residual oil zones (ROZs) where the mobile fluid phase is water and immobile phase is oil. But the nature of the formation and fluids within the ROZs has brought some challenges that were not present when flooding the MPZs. The Goldsmith-Landreth project in the Permian Basin was intended to first identify the most pressing issues of the ROZsmore » floods and, secondly, begin to address them with new techniques designed to optimize a flood that commingled the MPZ and the ROZ. The early phase of the research conducted considerable reservoir and fluid characterization work and identified both technical and commercial challenges of producing the enormous quantities of water when flooding the ROZs. It also noted the differing water compositions in the ROZ as compared to the overlying MPZs. A new CO 2 gas lift system using a capillary string was successfully applied during the project which conveyed the CO 2 to the deeper and differing ROZ reservoir conditions at Goldsmith and added a second capillary string that facilitated applying scale inhibitors to mitigate the scaling tendencies of the mixing ROZ and MPZ formation waters. The project also undertook a reservoir modeling effort, using the acquired reservoir characterization data, to history match both the primary and water flood phases of the MPZ and to establish the initial conditions for a modeling effort to forecast response of the ROZ to CO 2 EOR. With the advantage of many profile logs acquired from the operator, some concentration on the original pattern area for the ROZ pilot was accomplished to attempt to perfect the history match for that area. Several optional scenarios for producing the ROZ were simulated seeking to find the preferred mode of producing the two intervals. Finally, the project attempted to document for the first time the production performance of commingled MPZ and ROZ CO 2 EOR project at the nearby Seminole San Andres Unit. The analysis shows that over 10,000 bopd can be shown to be coming from the ROZ interval, a zone that would have produced no oil under primary or water flood phases. A similar analysis was done for the GLSAU project illustrating that 2000 bopd of incremental EOR oil is currently being produced. The results of the modeling work would suggest that 800 bopd can be attributed to the ROZ alone at GLSAU.« less

Using Polymer Alternating Gas to Enhance Oil Recovery in Heavy Oil

NASA Astrophysics Data System (ADS)

Yang, Yongzhi; Li, Weirong; Zhou, Tiyao; Dong, Zhenzhen

2018-02-01

CO2 has been used to recover oil for more than 40 years. Currently, about 43% of EOR production in U.S. is from CO2 flooding. CO2 flooding is a well-established EOR technique, but its density and viscosity nature are challenges for CO2 projects. Low density (0.5 to 0.8 g/cm3) causes gas to rise upward in reservoirs and bypass many lower portions of the reservoir. Low viscosity (0.02 to 0.08 cp) leads to poor volumetric sweep efficiency. So water-alternating-gas (WAG) method was used to control the mobility of CO2 and improve sweep efficiency. However, WAG process has some other problems in heavy oil reservoir, such as poor mobility ratio and gravity overriding. To examine the applicability of carbon dioxide to recover viscous oil from highly heterogeneous reservoirs, this study suggests a new EOR method--polymer-alternating gas (PAG) process. The process involves a combination of polymer flooding and CO2 injection. To confirm the effectiveness of PAG process in heavy oils, a reservoir model from Liaohe Oilfield is used to compare the technical and economic performance among PAG, WAG and polymer flooding. Simulation results show that PAG method would increase oil recovery over 10% compared with other EOR methods and PAG would be economically success based on assumption in this study. This study is the first to apply PAG to enhance oil recovery in heavy oil reservoir with highly heterogeneous. Besides, this paper provides detailed discussions and comparison about PAG with other EOR methods in this heavy oil reservoir.

Status of Foreground and Instrument Challenges for 21cm EoR experiments - Design Strategies for SKA and HERA

NASA Astrophysics Data System (ADS)

Thyagarajan, Nithyanandan

2018-05-01

Direct detection of the Epoch of Reionization (EoR) via redshifted 21 cm line of H i will reveal the nature of the first stars and galaxies as well as revolutionize our understanding of a poorly explored evolutionary phase of the Universe. Projects such as the MWA, LOFAR, and PAPER commenced in the last decade with the promise of high significance statistical detection of the EoR, but have so far only weakly constrained models owing to unforeseen challenges from bright foreground sources and instrument systematics. It is essential for next generation instruments like the HERA and SKA to have these challenges addressed. I present an analysis of these challenges - wide-field measurements, antenna beam chromaticity, reflections in the instrument, and antenna position errors - along with performance specifications and design solutions that will be critical to designing successful next-generation instruments in enabling the first detection and also in placing meaningful constraints on reionization models.

Rock formation characterization for CO2-EOR and carbon geosequestration; 3D seismic amplitude and coherency anomalies, Wellington Field, Kansas, USA

USGS Publications Warehouse

Ohl, D.; Raef, A.; Watnef, L.; Bhattacharya, S.

2011-01-01

In this paper, we present a workflow for a Mississipian carbonates characterization case-study integrating post-stack seismic attributes, well-logs porosities, and seismic modeling to explore relating changes in small-scale "lithofacies" properties and/or sub-seismic resolution faulting to key amplitude and coherency 3D seismic attributes. The main objective of this study is to put emphasis on reservoir characterization that is both optimized for and subsequently benefiting from pilot tertiary CO2-EOR in preparation for future carbon geosequestration in a depleting reservoir and a deep saline aquifer. The extracted 3D seismic coherency attribute indicated anomalous features that can be interpreted as a lithofacies change or a sub-seismic resolution faulting. A 2D finite difference modeling has been undertaken to understand and potentially build discriminant attributes to map structural and/or lithofacies anomalies of interest especially when embarking upon CO2-EOR and/or carbon sequestration monitoring and management projects. ?? 2011 Society of Exploration Geophysicists.

Maximize Liquid Oil Production from Shale Oil and Gas Condensate Reservoirs by Cyclic Gas Injection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sheng, James; Li, Lei; Yu, Yang

The current technology to produce shale oil reservoirs is the primary depletion using fractured wells (generally horizontal wells). The oil recovery is less than 10%. The prize to enhance oil recovery (EOR) is big. Based on our earlier simulation study, huff-n-puff gas injection has the highest EOR potential. This project was to explore the potential extensively and from broader aspects. The huff-n-puff gas injection was compared with gas flooding, water huff-n-puff and waterflooding. The potential to mitigate liquid blockage was also studied and the gas huff-n-puff method was compared with other solvent methods. Field pilot tests were initiated but terminatedmore » owing to the low oil price and the operator’s budget cut. To meet the original project objectives, efforts were made to review existing and relevant field projects in shale and tight reservoirs. The fundamental flow in nanopores was also studied.« less

Post waterflood CO{sub 2} miscible flood in light oil, fluvial-dominated deltaic reservoir. FY 1993 annual report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, D.W.

1995-03-01

The project is a Class 1 DOE-sponsored field demonstration project of a CO{sub 2} miscible flood project at the Port Neches Field in Orange County, Texas. The project will determine the recovery efficiency of CO{sub 2} flooding a waterflooded and a partial waterdrive sandstone reservoir at a depth of 5,800. The project will also evaluate the use of a horizontal CO{sub 2} injection well placed at the original oil-water contact of the waterflooded reservoir. A PC-based reservoir screening model will be developed by Texaco`s research lab in Houston and Louisiana State University will assist in the development of a databasemore » of fluvial-dominated deltaic reservoirs where CO{sub 2} flooding may be applicable. This technology will be transferred throughout the oil industry through a series of technical papers and industry open forums.« less

Improved Efficiency of Miscible CO(2) Floods and Enhanced Prospects for CO(2) Flooding Heterogeneous Reservoirs.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grigg, R.B.; Schechter, D.S.

The overall goal of this project was to improve the efficiency of miscible C0{sub 2} floods and enhance the prospects for flooding heterogeneous reservoirs. This objective was accomplished through experimental and modeling research in three task areas: (1) foams for selective mobility control in heterogeneous reservoirs,( 2) reduction of the amount of C0{sub 2} required in C0{sub 2} floods, and (3) low IFT processe and the possibility of C0{sub 2} flooding in fractured reservoirs. This report provides results from the three-year project for each of the three task areas.

Summary of the analyses for recovery factors

USGS Publications Warehouse

Verma, Mahendra K.

2017-07-17

IntroductionIn order to determine the hydrocarbon potential of oil reservoirs within the U.S. sedimentary basins for which the carbon dioxide enhanced oil recovery (CO2-EOR) process has been considered suitable, the CO2 Prophet model was chosen by the U.S. Geological Survey (USGS) to be the primary source for estimating recovery-factor values for individual reservoirs. The choice was made because of the model’s reliability and the ease with which it can be used to assess a large number of reservoirs. The other two approaches—the empirical decline curve analysis (DCA) method and a review of published literature on CO2-EOR projects—were deployed to verify the results of the CO2 Prophet model. This chapter discusses the results from CO2 Prophet (chapter B, by Emil D. Attanasi, this report) and compares them with results from decline curve analysis (chapter C, by Hossein Jahediesfanjani) and those reported in the literature for selected reservoirs with adequate data for analyses (chapter D, by Ricardo A. Olea).To estimate the technically recoverable hydrocarbon potential for oil reservoirs where CO2-EOR has been applied, two of the three approaches—CO2 Prophet modeling and DCA—do not include analysis of economic factors, while the third approach—review of published literature—implicitly includes economics. For selected reservoirs, DCA has provided estimates of the technically recoverable hydrocarbon volumes, which, in combination with calculated amounts of original oil in place (OOIP), helped establish incremental CO2-EOR recovery factors for individual reservoirs.The review of published technical papers and reports has provided substantial information on recovery factors for 70 CO2-EOR projects that are either commercially profitable or classified as pilot tests. When comparing the results, it is important to bear in mind the differences and limitations of these three approaches.

Prognostic value of resident clinical performance ratings.

PubMed

Williams, Reed G; Dunnington, Gary L

2004-10-01

This study investigated the concurrent and predictive validity of end-of-rotation (EOR) clinical performance ratings. Surgeon EOR ratings of residents were collected and compared with end-of-year (EOY) progress decisions and to EOR and EOY confidential judgments of resident ability to provide patient care without direct supervision. Eighty percent to 85% of EOR ratings were Excellent or Very Good. Five percent or fewer were Fair or Poor. Almost all residents receiving Excellent or Very Good EOR ratings also received positive EOR judgments about ability to provide patient care without direct supervision. Residents rated Fair or Poor received negative EOR judgments about ability to provide patient care without direct supervision. As the cumulative percent of Good, Fair, and Poor EOR ratings increased, the number of residents promoted without stipulations at the end of the year decreased and the percentage of faculty members who judged the residents capable of providing effective patient care without direct supervision at the end of the year declined. All residents receiving 40% or more EOR ratings below Very Good had stipulations associated with their promotion. Despite use of descriptive anchors on the scale, clinical performance ratings have no direct meaning. Their meaning needs to be established in the same manner as is done in setting normal values for diagnostic tests, ie, by establishing the relationship between EOR ratings and practice outcomes.

Molecular Probe Fluorescence Monitoring of Polymerization

NASA Technical Reports Server (NTRS)

Bunton, Patrick

2002-01-01

This project investigated the feasibility of using fluorescence spectroscopy to determine viscosity of polymer/monomer in support of Transient Interfacial Phenomena in Miscible Polymer Systems (TIPMPS). This project will attempt to measure gradient induced flow at a miscible interface during and / or after in-flight polymerization of dodecyl acrylate (lauryl acrylate). Concentration and temperature gradients will be intentionally introduced during polymerization and the resultant fluid flow determined by Particle Imaging Velocimetry (PIV). This report describes an investigation of the feasibility of using fluorescence of a probe molecule to monitor viscosity and/or concentration during and after polymerization. The probe used was pyrene which has been shown to be sensitive to its local environment in methyl methacrylate.

Carbon dioxide enhanced oil recovery performance according to the literature

USGS Publications Warehouse

Olea, Ricardo A.

2017-07-17

IntroductionThe need to increase the efficiency of oil recovery and environmental concerns are bringing to prominence the use of carbon dioxide (CO2) as a tertiary recovery agent. Assessment of the impact of flooding with CO2 all eligible reservoirs in the United States not yet undergoing enhanced oil recovery (EOR) requires making the best possible use of the experience gained in 40 years of applications. Review of the publicly available literature has located relevant CO2-EOR information for 53 units (fields, reservoirs, pilot areas) in the United States and 17 abroad.As the world simultaneously faces an increasing concentration of CO2 in the atmosphere and a higher demand for fossil fuels, the CO2-EOR process continues to gain popularity for its efficiency as a tertiary recovery agent and for the potential for having some CO2 trapped in the subsurface as an unintended consequence of the enhanced production (Advanced Resources International and Melzer Consulting, 2009). More extensive application of CO2-EOR worldwide, however, is not making it significantly easier to predict the exact outcome of the CO2 flooding in new reservoirs. The standard approach to examine and manage risks is to analyze the intended target by conducting laboratory work, running simulation models, and, finally, gaining field experience with a pilot test. This approach, though, is not always possible. For example, assessment of the potential of CO2-EOR at the national level in a vast country such as the United States requires making forecasts based on information already available.Although many studies are proprietary, the published literature has provided reviews of CO2-EOR projects. Yet, there is always interest in updating reports and analyzing the information under new perspectives. Brock and Bryan (1989) described results obtained during the earlier days of CO2-EOR from 1972 to 1987. Most of the recovery predictions, however, were based on intended injections of 30 percent the size of the reservoir’s hydrocarbon pore volume (HCPV), and the predictions in most cases badly missed the actual recoveries because of the embryonic state of tertiary recovery in general and CO2 flooding in particular at the time. Brock and Bryan (1989), for example, reported for the Weber Sandstone in the Rangely oil field in Colorado, an expected recovery of 7.5 percent of the original oil in place (OOIP) after injecting a volume of CO2 equivalent to 30 percent of the HCPV, but Clark (2012) reported that after injecting a volume of CO2 equivalent to 46 percent of the HCPV, the actual recovery was 4.8 percent of the OOIP. Decades later, the numbers by Brock and Bryan (1989) continue to be cited as part of expanded reviews, such as the one by Kuuskraa and Koperna (2006). Other comprehensive reviews including recovery factors are those of Christensen and others (2001) and Lake and Walsh (2008). The Oil and Gas Journal (O&GJ) periodically reports on active CO2-EOR operations worldwide, but those releases do not include recovery factors. The monograph by Jarrell and others (2002) remains the most technically comprehensive publication on CO2 flooding, but it does not cover recovery factors either.This chapter is a review of the literature found in a search for information about CO2-EOR. It has been prepared as part of a project by the U.S. Geological Survey (USGS) to assess the incremental oil production that would be technically feasible by CO2 flooding of all suitable oil reservoirs in the country not yet undergoing tertiary recovery.

Recovery Act: Develop a Modular Curriculum for Training University Students in Industry Standard CO{sub 2} Sequestration and Enhanced Oil Recovery Methodologies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trentham, R. C.; Stoudt, E. L.

CO{sub 2} Enhanced Oil Recovery, Sequestration, & Monitoring Measuring & Verification are topics that are not typically covered in Geoscience, Land Management, and Petroleum Engineering curriculum. Students are not typically exposed to the level of training that would prepare them for CO{sub 2} reservoir and aquifer sequestration related projects when they begin assignments in industry. As a result, industry training, schools & conferences are essential training venues for new & experienced personnel working on CO{sub 2} projects for the first time. This project collected and/or generated industry level CO{sub 2} training to create modules which faculties can utilize as presentations,more » projects, field trips and site visits for undergrad and grad students and prepare them to "hit the ground running" & be contributing participants in CO{sub 2} projects with minimal additional training. In order to create the modules, UTPB/CEED utilized a variety of sources. Data & presentations from industry CO{sub 2} Flooding Schools & Conferences, Carbon Management Workshops, UTPB Classes, and other venues was tailored to provide introductory reservoir & aquifer training, state-of-the-art methodologies, field seminars and road logs, site visits, and case studies for students. After discussions with faculty at UTPB, Sul Ross, Midland College, other universities, and petroleum industry professionals, it was decided to base the module sets on a series of road logs from Midland to, and through, a number of Permian Basin CO{sub 2} Enhanced Oil Recovery (EOR) projects, CO{sub 2} Carbon Capture and Storage (CCUS) projects and outcrop equivalents of the formations where CO{sub 2} is being utilized or will be utilized, in EOR projects in the Permian Basin. Although road logs to and through these projects exist, none of them included CO{sub 2} specific information. Over 1400 miles of road logs were created, or revised specifically to highlight CO{sub 2} EOR projects. After testing a number of different entry points into the data set with students and faculty form a number of different universities, it was clear that a standard website presentation with a list of available power point presentations, excel spreadsheets, word documents and pdf's would not entice faculty, staff, and students at universities to delve deeper into the website http://www.utpb.edu/ceed/student modules.« less

Transient enhanced diffusion in preamorphized silicon: the role of the surface

NASA Astrophysics Data System (ADS)

Cowern, N. E. B.; Alquier, D.; Omri, M.; Claverie, A.; Nejim, A.

1999-01-01

Experiments on the depth dependence of transient enhanced diffusion (TED) of boron during rapid thermal annealing of Ge-preamorphized layers reveal a linear decrease in the diffusion enhancement between the end-of-range (EOR) defect band and the surface. This behavior, which indicates a quasi-steady-state distribution of excess interstitials, emitted from the EOR band and absorbed at the surface, is observed for annealing times as short as 1 s at 900°C. Using an etching procedure we vary the distance xEOR from the EOR band to the surface in the range 80-175 nm, and observe how this influences the interstitial supersaturation, s( x). The supersaturations at the EOR band and the surface remain unchanged, while the gradient d s/d x, and thus the flux to the surface, varies inversely with xEOR. This confirms the validity of earlier modelling of EOR defect evolution in terms of Ostwald ripening, and provides conclusive evidence that the surface is the dominant sink for interstitials during TED.

Spatial Persistence of Macropores and Authigenic Clays in a Reservoir Sandstone: Implications for Enhanced Oil Recovery and CO2 Storage

NASA Astrophysics Data System (ADS)

Dewers, T. A.

2015-12-01

Multiphase flow in clay-rich sandstone reservoirs is important to enhanced oil recovery (EOR) and the geologic storage of CO2. Understanding geologic controls on pore structure allows for better identification of lithofacies that can contain, storage, and/or transmit hydrocarbons and CO2, and may result in better designs for EOR-CO2 storage. We examine three-dimensional pore structure and connectivity of sandstone samples from the Farnsworth Unit, Texas, the site of a combined EOR-CO2 storage project by the Southwest Regional Partnership on Carbon Sequestration (SWP). We employ a unique set of methods, including: robotic serial polishing and reflected-light imaging for digital pore-structure reconstruction; electron microscopy; laser scanning confocal microscopy; mercury intrusion-extrusion porosimetry; and relative permeability and capillary pressure measurements using CO2 and synthetic formation fluid. Our results link pore size distributions, topology of porosity and clay-rich phases, and spatial persistence of connected flow paths to multiphase flow behavior. The authors gratefully acknowledge the U.S. Department of Energy's National Energy Technology Laboratory for sponsoring this project through the SWP under Award No. DE-FC26-05NT42591. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

DOE Office of Scientific and Technical Information (OSTI.GOV)

P. Somasundaran

The aim of the project is to develop a knowledge base to help the design of enhanced processes for mobilizing and extracting untrapped oil. We emphasize evaluation of novel surfactant mixtures and obtaining optimum combinations of the surfactants for efficient chemical flooding EOR processes. In this regard, an understanding of the aggregate shape, size and structure is crucial since these properties govern the crude oil removal efficiency. During the three-year period, the adsorption and aggregation behavior of sugar-based surfactants and their mixtures with other types of surfactants have been studied. Sugar-based surfactants are made from renewable resources, nontoxic and biodegradable.more » They are miscible with water and oil. These environmentally benign surfactants feature high surface activity, good salinity, calcium and temperature tolerance, and unique adsorption behavior. They possess the characteristics required for oil flooding surfactants and have the potential for replacing currently used surfactants in oil recovery. A novel analytical ultracentrifugation technique has been successfully employed for the first time, to characterize the aggregate species present in mixed micellar solution due to its powerful ability to separate particles based on their size and shape and monitor them simultaneously. Analytical ultracentrifugation offers an unprecedented opportunity to obtain important information on mixed micelles, structure-performance relationship for different surfactant aggregates in solution and their role in interfacial processes. Initial sedimentation velocity investigations were conducted using nonyl phenol ethoxylated decyl ether (NP-10) to choose the best analytical protocol, calculate the partial specific volume and obtain information on sedimentation coefficient, aggregation mass of micelles. Four softwares: OptimaTM XL-A/XL-I data analysis software, DCDT+, Svedberg and SEDFIT, were compared for the analysis of sedimentation velocity experimental data. The results have been compared to that from Light Scattering. Based on the tests, Svedberg and SEDFIT analysis were chosen for further studies.« less

Simulation study to determine the feasibility of injecting hydrogen sulfide, carbon dioxide and nitrogen gas injection to improve gas and oil recovery oil-rim reservoir

NASA Astrophysics Data System (ADS)

Eid, Mohamed El Gohary

This study is combining two important and complicated processes; Enhanced Oil Recovery, EOR, from the oil rim and Enhanced Gas Recovery, EGR from the gas cap using nonhydrocarbon injection gases. EOR is proven technology that is continuously evolving to meet increased demand and oil production and desire to augment oil reserves. On the other hand, the rapid growth of the industrial and urban development has generated an unprecedented power demand, particularly during summer months. The required gas supplies to meet this demand are being stretched. To free up gas supply, alternative injectants to hydrocarbon gas are being reviewed to support reservoir pressure and maximize oil and gas recovery in oil rim reservoirs. In this study, a multi layered heterogeneous gas reservoir with an oil rim was selected to identify the most optimized development plan for maximum oil and gas recovery. The integrated reservoir characterization model and the pertinent transformed reservoir simulation history matched model were quality assured and quality checked. The development scheme is identified, in which the pattern and completion of the wells are optimized to best adapt to the heterogeneity of the reservoir. Lateral and maximum block contact holes will be investigated. The non-hydrocarbon gases considered for this study are hydrogen sulphide, carbon dioxide and nitrogen, utilized to investigate miscible and immiscible EOR processes. In November 2010, re-vaporization study, was completed successfully, the first in the UAE, with an ultimate objective is to examine the gas and condensate production in gas reservoir using non hydrocarbon gases. Field development options and proces schemes as well as reservoir management and long term business plans including phases of implementation will be identified and assured. The development option that maximizes the ultimate recovery factor will be evaluated and selected. The study achieved satisfactory results in integrating gas and oil reservoir management methodology to maximize both fluid recovery and free up currently injected HC gases for domestic consumption. Moreover, this study identified the main uncertainty parameters impacting the gas and oil production performance with all proposed alternatives. Maximizing both fluids oil and gas in oil rim reservoir are challenging. The reservoir heterogeneity will have a major impact on the performance of non hydrocarbon gas flooding. Therefore, good reservoir description is a key to achieve acceptable development process and make reliable prediction. The lab study data were used successfully to as a tool to identify the range of uncertainty parameters that are impacting the hydrocarbon recovery.

Post Waterflood CO2 Miscible Flood in Light Oil, Fluvial-Dominated Deltaic Reservoir, Class I

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bou-Mikael, Sami

This report demonstrates the effectiveness of the CO2 miscible process in Fluvial Dominated Deltaic reservoirs. It also evaluated the use of horizontal CO2 injection wells to improve the overall sweep efficiency. A database of FDD reservoirs for the gulf coast region was developed by LSU, using a screening model developed by Texaco Research Center in Houston. The results of the information gained in this project is disseminated throughout the oil industry via a series of SPE papers and industry open forums.

VizieR Online Data Catalog: EoR0 central field source catalog (Offringa+, 2016)

NASA Astrophysics Data System (ADS)

Offringa, A. R.; Trott, C. M.; Hurley-Walker, N.; Johnston-Hollitt, M.; McKinley, B.; Barry, N.; Beardsley, A. P.; Bowman, J. D.; Briggs, F.; Carroll, P.; Dillon, J. S.; Ewall-Wice, A.; Feng, L.; Gaensler, B. M.; Greenhill, L. J.; Hazelton, B. J.; Hewitt, J. N.; Jacobs, D. C.; Kim, H.-S.; Kittiwisit, P.; Lenc, E.; Line, J.; Loeb, A.; Mitchell, D. A.; Morales, M. F.; Neben, A. R.; Paul, S.; Pindor, B.; Pober, J. C.; Procopio, P.; Riding, J.; Sethi, S. K.; Shankar, N. U.; Subrahmanyan, R.; Sullivan, I. S.; Tegmark, M.; Thyagarajan, N.; Tingay, S. J.; Wayth, R. B.; Webster, R. L.; Wyithe, J. S. B.

2017-05-01

The observations used in this work have been made as part of the MWA EoR project. We have used observations that are centred at RA 0°, Dec. -27°, and recorded between 2013 August and October. The field around this target is referred to as the MWA EoR0 field - one of three fields that were selected based on having weak Galactic foregrounds and passing nearly through zenith at the MWA. The selected 15 nights are listed in Table 1. Of these 15 nights, 3 nights were not included in the analyses because they show RFI or unusual calibration solutions. The MWA can observe 30.72MHz simultaneously. To cover a larger redshift range, a total bandwidth of 138.9-197.7MHz is recorded by observing in two different bands. The low band covers 138.9-169.6MHz and the high band covers 167.0-197.7MHz. Together these cover the HI 21cm line at redshifts 6.1-9.2. The observations have a frequency resolution of 40kHz and time resolution of 0.5s. (1 data file).

MWA Observations of the EOR1 Field

NASA Astrophysics Data System (ADS)

Pindor, Bart

2018-05-01

The EOR1 field at (RA,DEC)=(4hrs, -30.0°) is one of the main targets of the MWA EOR experiment. It is notable for being in one of the coldest regions of the southern radio sky, as well as for containing the bright radio galaxy Fornax A. We report an early demonstration that the distance of this field from the Galactic Centre may make it a prime field for EOR observations.

The Dynamics of Miscible Interfaces: Simulations

NASA Technical Reports Server (NTRS)

Meiburg, Eckart

2005-01-01

This research project focuses on the dynamics of interfacial regions between miscible fluids. While much attention has focused on immiscible interfaces in the past, miscible interfaces have been explored to a much lesser degree, so that there are many open questions regarding their dynamics at this time. Among the more pressing issues is the role that nonconventional stresses can play in such interfacial regions. Such stresses are typically not accounted for in efforts to model the dynamics of miscible flows. Our research aims to clarify under which circumstances these stresses do have to be taken into account, and what quantitative approaches are most suitable in this regard. In order to address these issues, we have focused on conducting linear stability analyses and nonlinear simulations for capillary tube and Hele-Shaw flows, and to compare the results with corresponding experiments performed in the labs of our co-investigators Prof. Maxworthy at USC, and Dr. Balasubramaniam at NASA. Over the duration of the project we have, among other things, focused on the effects of variable diffusion coefficients in such flows, and specifically on their influence in the growth of instabilities. Furthermore, our three-dimensional spectral element simulations have made good progress, so that we have come to a point where we can conduct more detailed comparisons with experimental observations. We are currently focusing our efforts on reproducing the tip-splitting instability observed by Maxworthy. Finally, we have discovered a new core-annular flow instability in the Stokes flow regime during the last year. This represents a significant finding, as this instability does not have an immiscible counterpart.

DOE tallies Class III oil recovery field projects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1994-07-25

Here are details from midterm proposals submitted as part of the US Department of Energy's Class 3 oil recovery field demonstration candidate projects. All of the proposals emphasize dissemination of project details so that the results, if successful, can be applied widely in similar reservoirs. Project results will also be fed into a national petroleum technology transfer network. The proposals include: Gulf of Mexico, Gulf coast, offshore California, a California thermal, immiscible CO[sub 2], produced/potable water, microbial EOR, California diatomite, West Texas Spraberry field, and other Permian Basin fields.

Subtask – CO 2 storage and enhanced bakken recovery research program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sorensen, James; Hawthorne, Steven; Smith, Steven

Small improvements in productivity could increase technically recoverable oil in the Bakken Petroleum System by billions of barrels. The use of CO 2 for enhanced oil recovery (EOR) in tight oil reservoirs is a relatively new concept. The large-scale injection of CO 2 into the Bakken would also result in the geological storage of significant amounts of CO 2. The Energy & Environmental Research Center (EERC) has conducted laboratory and modeling activities to examine the potential for CO 2 storage and EOR in the Bakken. Specific activities included the characterization and subsequent modeling of North Dakota study areas as wellmore » as dynamic predictive simulations of possible CO 2 injection schemes to predict the potential CO 2 storage and EOR in those areas. Laboratory studies to evaluate the ability of CO 2 to remove hydrocarbons from Bakken rocks and determine minimum miscibility pressures for Bakken oil samples were conducted. Data from a CO 2 injection test conducted in the Elm Coulee area of Montana in 2009 were evaluated with an eye toward the possible application of knowledge gained to future injection tests in other areas. A first-order estimation of potential CO 2 storage capacity in the Bakken Formation in North Dakota was also conducted. Key findings of the program are as follows. The results of the research activities suggest that CO 2 may be effective in enhancing the productivity of oil from the Bakken and that the Bakken may hold the ability to geologically store between 120 Mt and 3.2 Gt of CO 2. However, there are no clear-cut answers regarding the most effective approach for using CO 2 to improve oil productivity or the storage capacity of the Bakken. The results underscore the notion that an unconventional resource will likely require unconventional methods of both assessment and implementation when it comes to the injection of CO 2. In particular, a better understanding of the fundamental mechanisms controlling the interactions between CO 2, oil, and other reservoir fluids in these unique formations is necessary to develop accurate assessments of potential CO 2 storage and EOR in the Bakken. In addition, existing modeling and simulation software packages do not adequately address or incorporate the unique properties of these tight, unconventional reservoirs in terms of their impact on CO 2 behavior. These knowledge gaps can be filled by conducting scaled-up laboratory activities integrated with improved modeling and simulation techniques, the results of which will provide a robust foundation for pilot-scale field injection tests. Finally, field-based data on injection, fluid production, and long-term monitoring from pilot-scale CO 2 injection tests in the Bakken are necessary to verify and validate the findings of the laboratory- and modeling-based research efforts. This subtask was funded through the EERC–U.S. Department of Energy (DOE) Joint Program on Research and Development for Fossil Energy-Related Resources Cooperative Agreement No. DE-FC26-08NT43291. Nonfederal funding was provided by the North Dakota Industrial Commission, Marathon Oil Corporation, Continental Resources Inc., and TAQA North, Ltd.« less

Sensitivity analysis and economic optimization studies of inverted five-spot gas cycling in gas condensate reservoir

NASA Astrophysics Data System (ADS)

Shams, Bilal; Yao, Jun; Zhang, Kai; Zhang, Lei

2017-08-01

Gas condensate reservoirs usually exhibit complex flow behaviors because of propagation response of pressure drop from the wellbore into the reservoir. When reservoir pressure drops below the dew point in two phase flow of gas and condensate, the accumulation of large condensate amount occurs in the gas condensate reservoirs. Usually, the saturation of condensate accumulation in volumetric gas condensate reservoirs is lower than the critical condensate saturation that causes trapping of large amount of condensate in reservoir pores. Trapped condensate often is lost due to condensate accumulation-condensate blockage courtesy of high molecular weight, heavy condensate residue. Recovering lost condensate most economically and optimally has always been a challenging goal. Thus, gas cycling is applied to alleviate such a drastic loss in resources. In gas injection, the flooding pattern, injection timing and injection duration are key parameters to study an efficient EOR scenario in order to recover lost condensate. This work contains sensitivity analysis on different parameters to generate an accurate investigation about the effects on performance of different injection scenarios in homogeneous gas condensate system. In this paper, starting time of gas cycling and injection period are the parameters used to influence condensate recovery of a five-spot well pattern which has an injection pressure constraint of 3000 psi and production wells are constraint at 500 psi min. BHP. Starting injection times of 1 month, 4 months and 9 months after natural depletion areapplied in the first study. The second study is conducted by varying injection duration. Three durations are selected: 100 days, 400 days and 900 days. In miscible gas injection, miscibility and vaporization of condensate by injected gas is more efficient mechanism for condensate recovery. From this study, it is proven that the application of gas cycling on five-spot well pattern greatly enhances condensate recovery preventing financial, economic and resource loss that previously occurred.

End-of-radiation PSA as a novel prognostic factor in patients undergoing definitive radiation and androgen deprivation therapy for prostate cancer.

PubMed

Narang, A K; Trieu, J; Radwan, N; Ram, A; Robertson, S P; He, P; Gergis, C; Griffith, E; Singh, H; DeWeese, T A; Honig, S; Annadanam, A; Greco, S; DeVille, C; McNutt, T; DeWeese, T L; Song, D Y; Tran, P T

2017-06-01

In men undergoing definitive radiation for prostate cancer, it is unclear whether early biochemical response can provide additional prognostic value beyond pre-treatment risk stratification. Prostate cancer patients consecutively treated with definitive radiation at our institution by a single provider from 1993 to 2006 and who had an end-of-radiation (EOR) PSA (n=688, median follow-up 11.2 years). We analyzed the association of an EOR PSA level, obtained during the last week of radiation, with survival outcomes. Multivariable-adjusted cox proportional hazards models were constructed to assess associations between a detectable EOR PSA (defined as ⩾0.1 ng ml -1 ) and biochemical failure-free survival (BFFS), metastasis-free survival (MFS), prostate cancer-specific survival (PCSS) and overall survival (OS). Kaplan-Meier survival curves were constructed, with stratification by EOR PSA. At the end of radiation, the PSA level was undetectable in 30% of patients. Men with a detectable EOR PSA experienced inferior 10-year BFFS (49.7% versus 64.4%, P<0.001), 10-year MFS (84.8% versus 92.0%, P=0.003), 10-year PCSS (94.3% versus 98.2%, P=0.007) and 10-year OS (75.8% versus 82.5%, P=0.01), as compared to men with an undetectable EOR PSA. Among National Comprehensive Care Network (NCCN) intermediate- and high-risk men who were treated with definitive radiation and androgen deprivation therapy (ADT), a detectable EOR PSA was more strongly associated with PCSS than initial NCCN risk level (EOR PSA: HR 5.89, 95% CI 2.37-14.65, P<0.001; NCCN risk level: HR 2.01, 95% CI 0.74-5.42, P=0.168). Main study limitations are retrospective study design and associated biases. EOR PSA was significantly associated with survival endpoints in men who received treatment with definitive radiation and ADT. Whether the EOR PSA can be used to modulate treatment intensity merits further investigation.

The role of CO2 capture and utilization in mitigating climate change

NASA Astrophysics Data System (ADS)

Mac Dowell, Niall; Fennell, Paul S.; Shah, Nilay; Maitland, Geoffrey C.

2017-04-01

To offset the cost associated with CO2 capture and storage (CCS), there is growing interest in finding commercially viable end-use opportunities for the captured CO2. In this Perspective, we discuss the potential contribution of carbon capture and utilization (CCU). Owing to the scale and rate of CO2 production compared to that of utilization allowing long-term sequestration, it is highly improbable the chemical conversion of CO2 will account for more than 1% of the mitigation challenge, and even a scaled-up enhanced oil recovery (EOR)-CCS industry will likely only account for 4-8%. Therefore, whilst CO2-EOR may be an important economic incentive for some early CCS projects, CCU may prove to be a costly distraction, financially and politically, from the real task of mitigation.

End-of-radiation PSA as a novel prognostic factor in patients undergoing definitive radiation and androgen deprivation therapy for prostate cancer

PubMed Central

Narang, Amol K.; Trieu, Janson; Radwan, Noura; Ram, Ashwin; Robertson, Scott P.; He, Pei; Gergis, Carol; Griffith, Emily; Singh, Harleen; DeWeese, Tate A.; Honig, Stephanie; Annadanam, Anvesh; Greco, Stephen; DeVille, Curtiland; McNutt, Todd; DeWeese, Theodore L.; Song, Daniel Y.; Tran, Phuoc T.

2016-01-01

Background In men undergoing definitive radiation for prostate cancer, it is unclear whether early biochemical response can provide additional prognostic value beyond pre-treatment risk stratification. Methods Prostate cancer patients consecutively treated with definitive radiation at our institution by a single provider from 1993–2006 and who had an EOR PSA (n=688, median follow-up 11.2 years). We analyzed the association of an end-of-radiation (EOR) prostate-specific antigen (PSA) level, obtained during the last week of radiation, with survival outcomes. Multivariable-adjusted cox proportional hazards models were constructed to assess associations between a detectable EOR PSA (defined as ≥0.1 ng ml−1) and biochemical failure-free survival (BFFS), metastasis-free survival (MFS), prostate cancer-specific survival (PCSS), and overall survival (OS). Kaplan-Meier survival curves were constructed, with stratification by EOR PSA. Results At the end of radiation, the PSA level was undetectable in 30% of patients. Men with a detectable EOR PSA experienced inferior 10-year BFFS (49.7% vs. 64.4%, p<0.001), 10-year MFS (84.8% vs. 92.0%, p=0.003), 10-year PCSS (94.3% vs. 98.2%, p=0.007), and 10-year OS (75.8% vs. 82.5%, p=0.01), as compared to men with an undetectable EOR PSA. Among NCCN intermediate- and high-risk men who were treated with definitive radiation and androgen deprivation therapy (ADT), a detectable EOR PSA was more strongly associated with PCSS than initial NCCN risk level (EOR PSA: HR 5.89, 95% CI 2.37–14.65, p<0.001; NCCN risk level: HR 2.01, 95% CI 0.74–5.42, p=0.168). Main study limitations are retrospective study design and associated biases. Conclusions EOR PSA was significantly associated with survival endpoints in men who received treated with definitive radiation and ADT. Whether the EOR PSA can be used to modulate treatment intensity merits further investigation. PMID:28094250

Explaining employment relationships with social exchange and job embeddedness.

PubMed

Hom, Peter W; Tsui, Anne S; Wu, Joshua B; Lee, Thomas W; Zhang, Ann Yan; Fu, Ping Ping; Li, Lan

2009-03-01

The research reported in this article clarifies how employee-organization relationships (EORs) work. Specifically, the authors tested whether social exchange and job embeddedness mediate how mutual-investment (whereby employers offer high inducements to employees for their high contributions) and over-investment (high inducements without corresponding high expected contributions) EOR approaches, which are based on Tsui, Pearce, Porter, and Tripoli's (1997) framework, affect quit propensity and organizational commitment. Two studies evaluated these intervening mechanisms. Study 1 surveyed 953 Chinese managers attending part-time master of business administration (MBA) programs in China, whereas Study 2 collected cross-sectional and longitudinal data from 526 Chinese middle managers in 41 firms. Standard and multilevel causal modeling techniques affirmed that social exchange and job embeddedness translate EOR influence. A second multilevel test using lagged outcome measures further established that job embeddedness mediates long-term EOR effects over 18 months. These findings corroborate prevailing views that social exchange explains how mutual- and over-investment EORs motivate greater workforce commitment and loyalty. This study enriches EOR perspectives by identifying job embeddedness as another mediator that is more enduring than social exchange. (c) 2009 APA, all rights reserved.

Ivacaftor and symptoms of extra-oesophageal reflux in patients with cystic fibrosis and G551D mutation.

PubMed

Zeybel, Gemma L; Pearson, Jeffrey P; Krishnan, Amaran; Bourke, Stephen J; Doe, Simon; Anderson, Alan; Faruqi, Shoaib; Morice, Alyn H; Jones, Rhys; McDonnell, Melissa; Zeybel, Mujdat; Dettmar, Peter W; Brodlie, Malcolm; Ward, Chris

2017-01-01

Extra-oesophageal reflux (EOR) may lead to microaspiration in patients with cystic fibrosis (CF), a probable cause of deteriorating lung function. Successful clinical trials of ivacaftor highlight opportunities to understand EOR in a real world study. Data from 12 patients with CF and the G551D mutation prescribed ivacaftor (150mg bd) was collected at baseline, 6, 26 and 52weeks. The changes in symptoms of EOR were assessed by questionnaire (reflux symptom index (RSI) and Hull airway reflux questionnaire (HARQ)). Six patients presented EOR at baseline (RSI >13; median 13; range 2-29) and 5 presented airway reflux (HARQ >13; median 12; range 3 to 33). Treatment with ivacaftor was associated with a significant reduction of EOR symptoms (P<0∙04 versus baseline) denoted by the reflux symptom index and Hull airway reflux questionnaire. Ivacaftor treatment was beneficial for patients with symptoms of EOR, thought to be a precursor to microaspiration. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Detectable end of radiation prostate specific antigen assists in identifying men with unfavorable intermediate-risk prostate cancer at high risk of distant recurrence and cancer-specific mortality.

PubMed

Hayman, Jonathan; Phillips, Ryan; Chen, Di; Perin, Jamie; Narang, Amol K; Trieu, Janson; Radwan, Noura; Greco, Stephen; Deville, Curtiland; McNutt, Todd; Song, Daniel Y; DeWeese, Theodore L; Tran, Phuoc T

2018-06-01

Undetectable End of Radiation PSA (EOR-PSA) has been shown to predict improved survival in prostate cancer (PCa). While validating the unfavorable intermediate-risk (UIR) and favorable intermediate-risk (FIR) stratifications among Johns Hopkins PCa patients treated with radiotherapy, we examined whether EOR-PSA could further risk stratify UIR men for survival. A total of 302 IR patients were identified in the Johns Hopkins PCa database (178 UIR, 124 FIR). Kaplan-Meier curves and multivariable analysis was performed via Cox regression for biochemical recurrence free survival (bRFS), distant metastasis free survival (DMFS), and overall survival (OS), while a competing risks model was used for PCa specific survival (PCSS). Among the 235 patients with known EOR-PSA values, we then stratified by EOR-PSA and performed the aforementioned analysis. The median follow-up time was 11.5 years (138 months). UIR was predictive of worse DMFS and PCSS (P = 0.008 and P = 0.023) on multivariable analysis (MVA). Increased radiation dose was significant for improved DMFS (P = 0.016) on MVA. EOR-PSA was excluded from the models because it did not trend towards significance as a continuous or binary variable due to interaction with UIR, and we were unable to converge a multivariable model with a variable to control for this interaction. However, when stratifying by detectable versus undetectable EOR-PSA, UIR had worse DMFS and PCSS among detectable EOR-PSA patients, but not undetectable patients. UIR was significant on MVA among detectable EOR-PSA patients for DMFS (P = 0.021) and PCSS (P = 0.033), while RT dose also predicted PCSS (P = 0.013). EOR-PSA can assist in predicting DMFS and PCSS among UIR patients, suggesting a clinically meaningful time point for considering intensification of treatment in clinical trials of intermediate-risk men. © 2018 Wiley Periodicals, Inc.

Area 2. Use Of Engineered Nanoparticle-Stabilized CO 2 Foams To Improve Volumetric Sweep Of CO 2 EOR Processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

DiCarlo, David; Huh, Chun; Johnston, Keith P.

2015-01-31

The goal of this project was to develop a new CO 2 injection enhanced oil recovery (CO 2-EOR) process using engineered nanoparticles with optimized surface coatings that has better volumetric sweep efficiency and a wider application range than conventional CO 2-EOR processes. The main objectives of this project were to (1) identify the characteristics of the optimal nanoparticles that generate extremely stable CO 2 foams in situ in reservoir regions without oil; (2) develop a novel method of mobility control using “self-guiding” foams with smart nanoparticles; and (3) extend the applicability of the new method to reservoirs having a widemore » range of salinity, temperatures, and heterogeneity. Concurrent with our experimental effort to understand the foam generation and transport processes and foam-induced mobility reduction, we also developed mathematical models to explain the underlying processes and mechanisms that govern the fate of nanoparticle-stabilized CO 2 foams in porous media and applied these models to (1) simulate the results of foam generation and transport experiments conducted in beadpack and sandstone core systems, (2) analyze CO 2 injection data received from a field operator, and (3) aid with the design of a foam injection pilot test. Our simulator is applicable to near-injection well field-scale foam injection problems and accounts for the effects due to layered heterogeneity in permeability field, foam stabilizing agents effects, oil presence, and shear-thinning on the generation and transport of nanoparticle-stabilized C/W foams. This report presents the details of our experimental and numerical modeling work and outlines the highlights of our findings.« less

On the use of sodium lignosulphonate for enhanced oil recovery

NASA Astrophysics Data System (ADS)

Azis, M. M.; Rachmadi, H.; Wintoko, J.; Yuliansyah, A. T.; Hasokowati, W.; Purwono, S.; Rochmadi, W.; Murachman, B.

2017-05-01

There has been large interest to utilize oil reservoirs in Indonesia by using Enhanced Oil Recovery (EOR) processes. Injection of surfactant as a part of chemical injection technique in EOR is known to aid the mobility and reduction in surface tension. One potential surfactant for EOR application is Sodium Lignosulphonate (SLS) which can be made from various sources particularly empty fruit bunch of oil palm and black liquor from kraft pulp production. Here, we will discuss a number of methods for SLS production which includes lignin isolation techniques and sulphonation reaction. The use of SLS alone as EOR surfactant, however, is often not feasible as the Interfacial Tension (IFT) value of SLS is typically above the order of 10-3 dyne/cm which is mandated for EOR application. Hence, brief discussion on SLS formulation screening is provided which illustrates an extensive labwork experience during the SLS development in our lab.

Intraoperative perception and estimates on extent of resection during awake glioma surgery: overcoming the learning curve.

PubMed

Lau, Darryl; Hervey-Jumper, Shawn L; Han, Seunggu J; Berger, Mitchel S

2018-05-01

OBJECTIVE There is ample evidence that extent of resection (EOR) is associated with improved outcomes for glioma surgery. However, it is often difficult to accurately estimate EOR intraoperatively, and surgeon accuracy has yet to be reviewed. In this study, the authors quantitatively assessed the accuracy of intraoperative perception of EOR during awake craniotomy for tumor resection. METHODS A single-surgeon experience of performing awake craniotomies for tumor resection over a 17-year period was examined. Retrospective review of operative reports for quantitative estimation of EOR was recorded. Definitive EOR was based on postoperative MRI. Analysis of accuracy of EOR estimation was examined both as a general outcome (gross-total resection [GTR] or subtotal resection [STR]), and quantitatively (5% within EOR on postoperative MRI). Patient demographics, tumor characteristics, and surgeon experience were examined. The effects of accuracy on motor and language outcomes were assessed. RESULTS A total of 451 patients were included in the study. Overall accuracy of intraoperative perception of whether GTR or STR was achieved was 79.6%, and overall accuracy of quantitative perception of resection (within 5% of postoperative MRI) was 81.4%. There was a significant difference (p = 0.049) in accuracy for gross perception over the 17-year period, with improvement over the later years: 1997-2000 (72.6%), 2001-2004 (78.5%), 2005-2008 (80.7%), and 2009-2013 (84.4%). Similarly, there was a significant improvement (p = 0.015) in accuracy of quantitative perception of EOR over the 17-year period: 1997-2000 (72.2%), 2001-2004 (69.8%), 2005-2008 (84.8%), and 2009-2013 (93.4%). This improvement in accuracy is demonstrated by the significantly higher odds of correctly estimating quantitative EOR in the later years of the series on multivariate logistic regression. Insular tumors were associated with the highest accuracy of gross perception (89.3%; p = 0.034), but lowest accuracy of quantitative perception (61.1% correct; p < 0.001) compared with tumors in other locations. Even after adjusting for surgeon experience, this particular trend for insular tumors remained true. The absence of 1p19q co-deletion was associated with higher quantitative perception accuracy (96.9% vs 81.5%; p = 0.051). Tumor grade, recurrence, diagnosis, and isocitrate dehydrogenase-1 (IDH-1) status were not associated with accurate perception of EOR. Overall, new neurological deficits occurred in 8.4% of cases, and 42.1% of those new neurological deficits persisted after the 3-month follow-up. Correct quantitative perception was associated with lower postoperative motor deficits (2.4%) compared with incorrect perceptions (8.0%; p = 0.029). There were no detectable differences in language outcomes based on perception of EOR. CONCLUSIONS The findings from this study suggest that there is a learning curve associated with the ability to accurately assess intraoperative EOR during glioma surgery, and it may take more than a decade to be truly proficient. Understanding the factors associated with this ability to accurately assess EOR will provide safer surgeries while maximizing tumor resection.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rychel, Dwight

The Permian Basin Carbon Capture, Utilization and Storage (CCUS) Training Center was one of seven regional centers formed in 2009 under the American Recovery and Reinvestment Act of 2009 and managed by the Department of Energy. Based in the Permian Basin, it is focused on the utilization of CO 2 Enhanced Oil Recovery (EOR) projects for the long term storage of CO 2 while producing a domestic oil and revenue stream. It delivers training to students, oil and gas professionals, regulators, environmental and academia through a robust web site, newsletter, tech alerts, webinars, self-paced online courses, one day workshops, andmore » two day high level forums. While course material prominently features all aspects of the capture, transportation and EOR utilization of CO 2, the audience focus is represented by its high level forums where selected graduate students with an interest in CCUS interact with Industry experts and in-house workshops for the regulatory community.« less

Fundamentals of carbon dioxide-enhanced oil recovery (CO2-EOR): a supporting document of the assessment methodology for hydrocarbon recovery using CO2-EOR associated with carbon sequestration

USGS Publications Warehouse

Verma, Mahendra K.

2015-01-01

The objective of this report is to provide basic technical information regarding the CO2-EOR process, which is at the core of the assessment methodology, to estimate the technically recoverable oil within the fields of the identified sedimentary basins of the United States. Emphasis is on CO2-EOR because this is currently one technology being considered as an ultimate long-term geologic storage solution for CO2 owing to its economic profitability from incremental oil production offsetting the cost of carbon sequestration.

Local and Global Impacts of Carbon Capture and Storage Combined with Enhanced Oil Recovery in Four Depleted Oil Fields, Kern County, California

NASA Astrophysics Data System (ADS)

Gillespie, J.; Jordan, P. D.; Goodell, J. A.; Harrington, K.; Jameson, S.

2015-12-01

Depleted oil reservoirs are attractive targets for geologic carbon storage (GCS) because they possess proven trapping mechanisms and large amounts of data pertaining to production and reservoir geometry. In addition, CO2 enhanced oil recovery (EOR) can improve recovery of the remaining oil at recovery factors of 6 to 20% of original oil in place in appropriate reservoirs. CO2 EOR increases the attractiveness of depleted oil and gas reservoirs as a starting point for CCS because the CO2 becomes a commodity that can be purchased by field operators for EOR purposes thereby offsetting the costs of CO2 capture at the power plant. In California, Kern County contains the largest oil reservoirs and produces 76% of California's oil. Most of the production at depths suitable for CCS combined with CO2 EOR comes from three reservoirs: the Vedder and Temblor formations and the Stevens Sandstone of the Monterey Formation. These formations were evaluated for GCS and CO2 EOR potential at the North and South Coles Levee (Stevens Sandstone), Greeley (Vedder) and McKittrick (Temblor) fields. CO2 EOR could be expected to produce an additional 150 million bbls of oil. The total storage space created by pre- and post-EOR fluid production for all three reservoirs is approximately 104 million metric tons (MMT). Large fixed sources in California produce 156 MMT/yr of CO2, and sources in Kern County produce 26 MMT/yr (WESTCARB, 2012). Therefore, the fields could store about four years of local large fixed source emissions and about two thirds of statewide emissions. However, from a global perspective, burning the additional oil produced by CO2 EOR would generate an additional 65 MMT of CO2 if not captured. This would result in a net reduction of greenhouse gas of only 39 MMT rather than the full 104 MMT. If the water produced along with the oil recovered during CO2 EOR operations is not reinjected into the reservoir, the storage space could be much higher.

Fluid Flow Simulation For CO2-EOR and Sequestration Utilizing Geomechanical Constraints - Teapot Dome Oil Field, Wyoming

NASA Astrophysics Data System (ADS)

Chiaramonte, L.; Zoback, M. D.; Friedmann, J.; Stamp, V.

2007-12-01

Mature oil and gas reservoirs are attractive targets for geological sequestration of CO2 because of their potential storage capacities and the possible cost offsets from enhanced oil recovery (EOR). In this work we develop a 3D reservoir model and fluid flow simulation of the Tensleep Formation using geomechanical constraints to evaluate the feasibility of a CO2-EOR injection project at Teapot Dome Oil Field, WY. The objective of this work is to model the migration of the injected CO2 as well as to obtain limits on the rates and volumes of CO2 that can be injected without compromising seal integrity. Teapot Dome is an elongated asymmetrical, basement-cored anticline with a north-northwest axis. It is part of the Salt Creek structural trend, located in the southwestern edge of the Powder River Basin. The Tensleep Fm. in this area consists of interdune deposits such as eolian sandstones, sabkha carbonates, evaporites (mostly anhydrite), and some very low permeability dolomicrites. The average porosity is 0.10 ranging from 0.05-0.20. The average permeability is 30 mD, ranging from 10 - 100 mD. The average reservoir thickness is 50 ft. The reservoir has strong aquifer drive. In the area under study, the Tensleep Fm. has its structural crest at 1675 m. It presents a 3-way closure trap against a NE-SW fault to the north. We previously carried out a geomechanical stability analysis and found this fault to be able to support the increase in pressure due to the CO2 to be injected, even if the structure was "filled-to-spill". In this work we combine our previous geomechanical analysis, geostatistical reservoir modeling and fluid flow simulations to investigate critical questions regarding the feasibility of a CO2-EOR project in the Tensleep Fm. The analysis takes into consideration the initial trapping and sealing mechanisms of the reservoir, the consequences of past and present oil production on the initial properties, and the potential effect of CO2 injection on both the reservoir and the seal. Finally, we want to predict the long-term oil recovery of the injection site and what will happen in the system once oil production stops.

Project Columbiad: Reestablishment of human presence on the Moon

NASA Technical Reports Server (NTRS)

Shea, Joseph; Weiss, Stanley; Alexander, Harold; Belobaba, Peter; Loboda, Greg; Berry, Maresi; Bower, Mark; Bruen, Charles; Cazeau, Patrick; Clarke, Michael

1992-01-01

In response to the Report of the Advisory Committee on the future of the U.S. Space Program and a request from NASA's Exploration Office, the MIT Hunsaker Aerospace Corporation (HAC) conducted a feasibility study, known as Project Columbiad, on reestablishing human presence on the Moon before the year 2000. The mission criteria established were to transport a four person crew to the lunar surface at any latitude and back to Earth with a 14-28 day stay on the lunar surface. Safety followed by cost of the Columbiad Mission were the top level priorities of HAC. The resulting design has a precursor mission that emplaces the required surface payloads before the piloted mission arrives. Both the precursor and piloted missions require two National Launch System (NLS) launches. Both the precursor and piloted missions have an Earth orbit rendezvous (EOR) with a direct transit to the Moon post-EOR. The piloted mission returns to Earth via a direct transit. Included among the surface payloads preemplaced are a habitat, solar power plant (including fuel cells for the lunar night), lunar rover, and mecanisms used to cover the habitat with regolith (lunar soil) in order to protect the crew members from severe solar flare radiation.

Results from the MWA EoR Experiment

NASA Astrophysics Data System (ADS)

Webster, Rachel L.; MWA EoR Collaboration

2018-05-01

The MWA EoR is one of a small handful of experiments designed to detect the statistical signal from the Epoch of Reionisation. Each of these experiments has reached a level of maturity, where the challenges, in particular of foreground removal, are being more fully understood. Over the past decade, the MWA EoR Collaboration has developed expertise and an understanding of the elements of the telescope array, the end-to-end pipelines, ionospheric conditions, and and the foreground emissions. Sufficient data has been collected to detect the theoretically predicted EoR signal. Limits have been published regularly, however we still several orders of magnitude from a possible detection. This paper outlines recent progress and indicates directions for future efforts.

Determination of Earth outgoing radiation using a constellation of satellites

NASA Astrophysics Data System (ADS)

Gristey, Jake; Chiu, Christine; Gurney, Robert; Han, Shin-Chan; Morcrette, Cyril

2017-04-01

The outgoing radiation fluxes at the top of the atmosphere, referred to as Earth outgoing radiation (EOR), constitute a vital component of the Earth's energy budget. This EOR exhibits strong diurnal signatures and is inherently connected to the rapidly evolving scene from which the radiation originates, so our ability to accurately monitor EOR with sufficient temporal resolution and spatial coverage is crucial for weather and climate studies. Despite vast improvements in satellite observations in recent decades, achieving these criteria remains challenging from current measurements. A technology revolution in small satellites and sensor miniaturisation has created a new and exciting opportunity for a novel, viable and sustainable observation strategy from a constellation of satellites, capable of providing both global coverage and high temporal resolution simultaneously. To explore the potential of a constellation approach for observing EOR we perform a series of theoretical simulation experiments. Using the results from these simulation experiments, we will demonstrate a baseline constellation configuration capable of accurately monitoring global EOR at unprecedented temporal resolution. We will also show whether it is possible to reveal synoptic scale, fast evolving phenomena by applying a deconvolution technique to the simulated measurements. The ability to observe and understand the relationship between these phenomena and changes in EOR is of fundamental importance in constraining future warming of our climate system.

Global Earth Outgoing Radiation From A Constellation Of Satellites: Proof-Of-Concept Study

NASA Astrophysics Data System (ADS)

Gristey, J. J.; Chiu, J. Y. C.; Gurney, R. J.; Han, S. C.; Morcrette, C. J.

2017-12-01

The flux of radiation exiting at the top of the atmosphere, referred to as Earth Outgoing Radiation (EOR), constitutes a vital component of the Earth's energy budget. Since EOR is inherently connected to the rapidly evolving scene from which the radiation originates and exhibits large regional variations, it is of paramount importance that we can monitor EOR at a sufficient frequency and spatial scale for weather and climate studies. Achieving these criteria remains challenging using traditional measurement techniques. However, explosive development in small satellite technology and sensor miniaturisation has paved a viable route for measurements to be made from a constellation of satellites in different orbits. This offers an exciting new opportunity to make observations of EOR with both global coverage and high temporal resolution for the first time. To assess the potential of the constellation approach for observing EOR we perform a series of observing system simulation experiments. We will outline a baseline constellation configuration capable of sampling the Earth with unprecedented temporal resolution. Using this configuration and a sophisticated deconvolution technique, we demonstrate how to recover synoptic-scale global EOR to the accuracy required to understand Earth's global energy budget. Finally, we will reveal the impact of various modifications to the constellation configuration and provide recommendations for the community.

An early deployment strategy for carbon capture, utilisation, and storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carter, L.D.

2012-11-01

This report describes the current use of CO2 for EOR, and discusses potential expansion of EOR using CO2 from power plants. Analysis of potential EOR development in the USA, where most current CO2-based EOR production takes place, indicates that relatively low cost, traditional sources of CO2 for EOR (CO2 domes and CO2 from natural gas processing plants) are insufficient to exploit the full potential of EOR. To achieve that full potential will require use of CO2 from combustion and gasification systems, such as fossil fuel power plants, where capture of CO2 is more costly. The cost of current CCUS systems,more » even with the revenue stream for sale of the CO2 for EOR, is too high to result in broad deployment of the technology in the near term. In the longer term, research and development may be sufficient to reduce CO2 capture costs to a point where CCUS would be broadly deployed. This report describes a case study of conditions in the USA to explore a financial incentive to promote early deployment of CCUS, providing a range of immediate benefits to society, greater likelihood of reducing the long-term cost of CCUS, and greater likelihood of broad deployment of CCUS and CCS in the long term. Additionally, it may be possible to craft such an incentive in a manner that its cost is more than offset by taxes flowing from increased domestic oil production. An example of such an incentive is included in this report.« less

Design and implementation of four enhanced recovery projects in bay fields of South Louisiana

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boardman, R.S.; Moore, L.J.; Julian, M.H.

1982-01-01

This paper reviews the design and implementation of four enhanced recovery projects that were initiated in the shallow-water environment of two bay fields located along the coastline of South Louisiana. These four projects are a caustic augmented waterflood, a miscible carbon dioxide waterflood, both in Quarantine Bay Field, and two polymer augmented waterfloods in the West Bay Field. The paper focuses on the design modifications required for the projects due to the hostile overwater environment and the logistics problems associated with the locations of the projects. 4 refs.

Design and implementation of four enhanced recovery projects in bay fields of south Louisiana

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boardman, R.S.; Moore, L.J.; Julian, M.H.

1982-01-01

This paper reviews the design and implementation of four enhanced recovery projects that were initiated in the shallow-water environment of two bay fields located along the coastline of South Louisiana. These four projects are a caustic augmented waterflood, a miscible carbon dioxide waterflood, both in Quarantine Bay Field, and two polymer augmented waterfloods in the West Bay Field. The paper focuses on the design modifications required for the projects due to the hostile overwater environment and the logistics problems associated with the locations of the projects.

Fate(s) of injected CO2 in a coal-bearing formation, Louisiana, Gulf Coast Basin: Chemical and isotopic tracers of microbial-brine-rock-CO2 interactions

USGS Publications Warehouse

Shelton, Jenna L.

2013-01-01

Coal beds are one of the most promising reservoirs for geologic carbon dioxide (CO₂) sequestration, as CO₂ can strongly adsorb onto organic matter and displace methane; however, little is known about the long-term fate of CO₂ sequestered in coal beds. The "2800' sand" of the Olla oil field is a coal-bearing, oil and gas-producing reservoir of the Paleocene–Eocene Wilcox Group in north-central Louisiana. In the 1980s, this field, specifically the 2800' sand, was flooded with CO₂ in an enhanced oil recovery (EOR) project, with 9.0×10⁷m³ of CO₂ remaining in the 2800' sand after injection ceased. This study utilized isotopic and geochemical tracers from co-produced natural gas, oil and brine from reservoirs located stratigraphically above, below and within the 2800' sand to determine the fate of the remaining EOR-CO₂, examining the possibilities of CO₂ migration, dissolution, mineral trapping, gas-phase trapping, and sorption to coal beds, while also testing a previous hypothesis that EOR-CO₂ may have been converted by microbes (CO₂-reducing methanogens) into methane, creating a microbial "hotspot". Reservoirs stratigraphically-comparable to the 2800' sand, but located in adjacent oil fields across a 90-km transect were sampled to investigate regional trends in gas composition, brine chemistry and microbial activity. The source field for the EOR-CO₂, the Black Lake Field, was also sampled to establish the δ¹³C-CO₂ value of the injected gas (0.9‰ +/- 0.9‰). Four samples collected from the Olla 2800' sand produced CO₂-rich gas with δ¹³C-CO₂ values (average 9.9‰) much lower than average (pre-injection) conditions (+15.9‰, average of sands located stratigraphically below the 2800' sand in the Olla Field) and at much higher CO₂ concentrations (24.9 mole %) than average (7.6 mole %, average of sands located stratigraphically below the 2800' sand in the Olla Field), suggesting the presence of EOR-CO₂ and gas-phase trapping as a major storage mechanism. Using δ¹³C values of CO₂ and dissolved organic carbon (DIC), CO₂ dissolution was also shown to be a major storage mechanism for 3 of the 4 samples from the Olla 2800' sand. Minor storage mechanisms were shown to be migration, which only affected 2 samples (from 1 well), and some EOR-CO₂ conversion to microbial methane for 3 of the 4 Olla 2800' sand samples. Since methanogenesis was not shown to be a major storage mechanism for the EOR-CO₂ in the Olla Field (CO₂ injection did not stimulate methanogenesis), samples were examined from adjacent oil fields to determine the cause of the Olla microbial "hot-spot". Microbial methane was found in all oil fields sampled, but indicators of methanogenesis (e.g. alkalinity, high δ¹³C-DIC values) were the greatest in the Olla Field, and the environmental conditions (salinity, pH, temperature) were most ideal for microbial CO₂ reduction in the Olla field, compared to adjacent fields.

Production report: enhanced recovery. [Combustion, steam, soak steam drive, polymer and caustic, micellar/surfactant miscible hydrocarbons and CO/sub 2/

DOE Office of Scientific and Technical Information (OSTI.GOV)

Noran, D.

Schemes for producing additional oil using enhanced-recovery (ER) methods are under way throughout the world. The extent and intensity of ER activity is highest in the U.S. with 156 projects, about two-thirds of which are thermal. Venezuela has a strong ER commitment with at least 70 active projects, with a major thrust on steam soak. Significant projects, but limited in number, are under way in Canada, North Africa, Southeast Asia, and elsewhere in Latin America. A breakdown of active U.S. ER projects for 1970, 1973, and 1975 is tabulated for combustion, steam soak, steam drive, polymer and caustic, micellar/surfactant, misciblemore » hydrocarbon, and CO/sub 2/ methods. This Oil and Gas Journal Survey includes seven articles; the first six were prepared by David Noran, Journal Production Editor. The final article on Venezuelan activity was written by Alvaro Franco, Editor and Publisher, Petroleo Internacional. The articles are entitled: U.S. Thermal Recovery Activity Growing Steadily; Operators Accelerate Testing of Micellar/Surfactant Potential; Polymer and Caustic Methods on Rebound; Gas Miscible Projects Move at Slow Pace; Canadian Enhanced-Recovery Activity Moderate, Centers on Thermal Projects; Other Global Enhanced-Recovery Work Sparse; and Thermal Work Humming in Venezuela. Detailed information on each method is tabulated for each article. (MCW)« less

Tracing enhanced oil recovery signatures in casing gases from the Lost Hills oil field using noble gases

USGS Publications Warehouse

Barry, Peter H.; Kulongoski, Justin; Landon, Matthew K.; Tyne, R.L.; Gillespie, Janice; Stephens, Michael; Hillegonds, D.J.; Byrne, D.J.; Ballentine, C.J.

2018-01-01

Enhanced oil recovery (EOR) and hydraulic fracturing practices are commonly used methods to improve hydrocarbon extraction efficiency; however the environmental impacts of such practices remain poorly understood. EOR is particularly prevalent in oil fields throughout California where water resources are in high demand and disposal of high volumes of produced water may affect groundwater quality. Consequently, it is essential to better understand the fate of injected (EOR) fluids in California and other subsurface petroleum systems, as well as any potential effect on nearby aquifer systems. Noble gases can be used as tracers to understand hydrocarbon generation, migration, and storage conditions, as well as the relative proportions of oil and water present in the subsurface. In addition, a noble gas signature diagnostic of injected (EOR) fluids can be readily identified. We report noble gas isotope and concentration data in casing gases from oil production wells in the Lost Hills oil field, northwest of Bakersfield, California, and injectate gas data from the Fruitvale oil field, located within the city of Bakersfield. Casing and injectate gas data are used to: 1) establish pristine hydrocarbon noble-gas signatures and the processes controlling noble gas distributions, 2) characterize the noble gas signature of injectate fluids, 3) trace injectate fluids in the subsurface, and 4) construct a model to estimate EOR efficiency. Noble gas results range from pristine to significantly modified by EOR, and can be best explained using a solubility exchange model between oil and connate/formation fluids, followed by gas exsolution upon production. This model is sensitive to oil-water interaction during hydrocarbon expulsion, migration, and storage at reservoir conditions, as well as any subsequent modification by EOR.

Uncertainty Quantification for CO2-Enhanced Oil Recovery

NASA Astrophysics Data System (ADS)

Dai, Z.; Middleton, R.; Bauman, J.; Viswanathan, H.; Fessenden-Rahn, J.; Pawar, R.; Lee, S.

2013-12-01

CO2-Enhanced Oil Recovery (EOR) is currently an option for permanently sequestering CO2 in oil reservoirs while increasing oil/gas productions economically. In this study we have developed a framework for understanding CO2 storage potential within an EOR-sequestration environment at the Farnsworth Unit of the Anadarko Basin in northern Texas. By coupling a EOR tool--SENSOR (CEI, 2011) with a uncertainty quantification tool PSUADE (Tong, 2011), we conduct an integrated Monte Carlo simulation of water, oil/gas components and CO2 flow and reactive transport in the heterogeneous Morrow formation to identify the key controlling processes and optimal parameters for CO2 sequestration and EOR. A global sensitivity and response surface analysis are conducted with PSUADE to build numerically the relationship among CO2 injectivity, oil/gas production, reservoir parameters and distance between injection and production wells. The results indicate that the reservoir permeability and porosity are the key parameters to control the CO2 injection, oil and gas (CH4) recovery rates. The distance between the injection and production wells has large impact on oil and gas recovery and net CO2 injection rates. The CO2 injectivity increases with the increasing reservoir permeability and porosity. The distance between injection and production wells is the key parameter for designing an EOR pattern (such as a five (or nine)-spot pattern). The optimal distance for a five-spot-pattern EOR in this site is estimated from the response surface analysis to be around 400 meters. Next, we are building the machinery into our risk assessment framework CO2-PENS to utilize these response surfaces and evaluate the operation risk for CO2 sequestration and EOR at this site.

4-D High-Resolution Seismic Reflection Monitoring of Miscible CO2 Injected into a Carbonate Reservoir

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richard D. Miller; Abdelmoneam E. Raef; Alan P. Byrnes

2005-09-01

The objective of this research project is to acquire, process, and interpret multiple high-resolution 3-D compressional wave and 2-D, 2-C shear wave seismic data to observe changes in fluid characteristics in an oil field before, during, and after the miscible carbon dioxide (CO{sub 2}) flood that began around December 1, 2003, as part of the DOE-sponsored Class Revisit Project (DOE DE-AC26-00BC15124). Unique and key to this imaging activity is the high-resolution nature of the seismic data, minimal deployment design, and the temporal sampling throughout the flood. The 900-m-deep test reservoir is located in central Kansas oomoldic limestones of the Lansing-Kansasmore » City Group, deposited on a shallow marine shelf in Pennsylvanian time. After 18 months of seismic monitoring, one baseline and six monitor surveys clearly imaged changes that appear consistent with movement of CO{sub 2} as modeled with fluid simulators.« less

Electro-Optical Rectifier (EOR) Update Study

DTIC Science & Technology

1976-05-01

Errors and physical imperfections in paper tape, which is generated by a sepa- rate computer system to drive the EOR, have also limited the...of wrong parameters or other such unpredict- able events Since no physical storage medium such as paper tape or magnetic taiU is used to convey...printing. This is useful to determine whether or not EOR physical limits are exceeded without ruining a piece of film. The trial run can be made at a

Geochemical Modeling of Carbon Sequestration, MMV, and EOR in the Illinois Basin

USGS Publications Warehouse

Berger, P.M.; Roy, W.R.; Mehnert, E.

2009-01-01

The Illinois State Geologic Survey is conducting several ongoing CO2 sequestration projects that require geochemical models to gain an understanding of the processes occurring in the subsurface. The ISGS has collected brine and freshwater samples associated with an enhanced oil recovery project in the Loudon oil field. Geochemical modeling allows us to understand reactions with carbonate and silicate minerals in the reservoir, and the effects they have had on brine composition. For the Illinois Basin Decatur project, geochemical models should allow predictions of the reactions that will take place before CO2 injection begins. ?? 2009 Elsevier Ltd. All rights reserved.

Frontal Polymerization in Microgravity Summary of Research

NASA Technical Reports Server (NTRS)

Pojman, John A.

2002-01-01

The project began with frontal polymerization (FP). We studied many aspects of FP on the ground and performed two successful weeks of flying on the KC-135. The project evolved into the current flight investigation, Transient Interfacial Phenomena in Miscible Polymer Systems (TIPMPS), as we recognized that an essential question could best be studied using a non-frontal approach. We present detailed results from our ground-based work on FP, KC-135 results and the background, justification and numerical work for the TIPMPS project.

Characterization, Monitoring, and Risk Assessment at the IEA GHG Weyburn-Midale CO2 Monitoring and Storage Project, Saskatchewan, Canada.

NASA Astrophysics Data System (ADS)

Ben, R.; Chalaturnyk, R.; Gardner, C.; Hawkes, C.; Johnson, J.; White, D.; Whittaker, S.

2008-12-01

In July 2000, a major research project was initiated to study the geological storage of CO2 as part of a 5000 tonnes/day EOR project planned for the Weyburn Field in Saskatchewan, Canada. Major objectives of the IEA GHG Weyburn CO2 monitoring and storage project included: assessing the integrity of the geosphere encompassing the Weyburn oil pool for effective long-term storage of CO2; monitoring the movement of the injected CO2, and assessing the risk of migration of CO2 from the injection zone (approximately 1500 metres depth) to the surface. Over the period 2000-2004, a diverse group of 80+ researchers worked on: geological, geophysical, and hydrogeological characterizations at both the regional (100 km beyond the field) and detailed scale (10 km around the field); conducted time-lapse geophysical surveys; carried out surface and subsurface geochemical surveys; and undertook numerical reservoir simulations. Results of the characterization were used for a performance assessment that concluded the risk of CO2 movement to the biosphere was very small. By September 2007, more than 14 Mtonnes of CO2 had been injected into the Weyburn reservoir, including approximately 3 Mtonnes recycled from oil production. A "Final Phase" research project was initiated (2007- 2011) to contribute to a "Best Practices" guide for long-term CO2 storage in EOR settings. Research objectives include: improving the geoscience characterization; further detailed analysis and data collection on the role of wellbores; additional geochemical and geophysical monitoring activities; and an emphasis on quantitative risk assessments using multiple analysis techniques. In this talk a review of results from Phase I will be presented followed by plans and initial results for the Final Phase.

Project Columbiad: Mission to the Moon. Book 1: Executive Summary. Volume 1: Mission trade studies and requirements. Volume 2: Subsystem trade studies and selection

NASA Technical Reports Server (NTRS)

Clarke, Michael; Denecke, Johan; Garber, Suzanne; Kader, Beth; Liu, Celia; Weintraub, Ben; Cazeau, Patrick; Goetz, John; Haughwout, James; Larson, Erik

1992-01-01

In response to the Report of the Advisory Committee on the future of the U.S. Space Program and a request from NASA's Exploration Office, the MIT Hunsaker Aerospace Corporation (HAC) conducted a feasibility study, known as Project Columbiad, on reestablishing human presence on the Moon before the year 2000. The mission criteria established were to transport a four person crew to the lunar surface at any latitude and back to Earth with a 14-28 day stay on the lunar surface. Safety followed by cost of the Columbiad Mission were the top level priorities of HAC. The resulting design has a precursor mission that emplaces the required surface payloads before the piloted mission arrives. Both the precursor and piloted missions require two National Launch System (NLS) launches. Both the precursor and piloted mission have an Earth orbit rendezvous (EOR) with a direct transit to the Moon post-EOR. The piloted mission returns to Earth via a direct transit. Included among the surface payloads preemplaced are a habitat, solar power plant (including fuel cells for the lunar night), lunar rover, and mechanisms used to cover the habitat with regolith (lunar soil) in order to protect the crew members from severe solar flare radiation.

Understanding USGS user needs and Earth observing data use for decision making

NASA Astrophysics Data System (ADS)

Wu, Z.

2016-12-01

US Geological Survey (USGS) initiated the Requirements, Capabilities and Analysis for Earth Observations (RCA-EO) project in the Land Remote Sensing (LRS) program, collaborating with the National Oceanic and Atmospheric Administration (NOAA) to jointly develop the supporting information infrastructure - The Earth Observation Requirements Evaluation Systems (EORES). RCA-EO enables us to collect information on current data products and projects across the USGS and evaluate the impacts of Earth observation data from all sources, including spaceborne, airborne, and ground-based platforms. EORES allows users to query, filter, and analyze usage and impacts of Earth observation data at different organizational level within the bureau. We engaged over 500 subject matter experts and evaluated more than 1000 different Earth observing data sources and products. RCA-EO provides a comprehensive way to evaluate impacts of Earth observing data on USGS mission areas and programs through the survey of 345 key USGS products and services. We paid special attention to user feedback about Earth observing data to inform decision making on improving user satisfaction. We believe the approach and philosophy of RCA-EO can be applied in much broader scope to derive comprehensive knowledge of Earth observing systems impacts and usage and inform data products development and remote sensing technology innovation.

Effects of Antenna Beam Chromaticity on Redshifted 21 cm Power Spectrum and Implications for Hydrogen Epoch of Reionization Array

NASA Astrophysics Data System (ADS)

Thyagarajan, Nithyanandan; Parsons, Aaron R.; DeBoer, David R.; Bowman, Judd D.; Ewall-Wice, Aaron M.; Neben, Abraham R.; Patra, Nipanjana

2016-07-01

Unaccounted for systematics from foregrounds and instruments can severely limit the sensitivity of current experiments from detecting redshifted 21 cm signals from the Epoch of Reionization (EoR). Upcoming experiments are faced with a challenge to deliver more collecting area per antenna element without degrading the data with systematics. This paper and its companions show that dishes are viable for achieving this balance using the Hydrogen Epoch of Reionization Array (HERA) as an example. Here, we specifically identify spectral systematics associated with the antenna power pattern as a significant detriment to all EoR experiments which causes the already bright foreground power to leak well beyond ideal limits and contaminate the otherwise clean EoR signal modes. A primary source of this chromaticity is reflections in the antenna-feed assembly and between structures in neighboring antennas. Using precise foreground simulations taking wide-field effects into account, we provide a generic framework to set cosmologically motivated design specifications on these reflections to prevent further EoR signal degradation. We show that HERA will not be impeded by such spectral systematics and demonstrate that even in a conservative scenario that does not perform removal of foregrounds, HERA will detect the EoR signal in line-of-sight k-modes, {k}\\parallel ≳ 0.2 h Mpc-1, with high significance. Under these conditions, all baselines in a 19-element HERA layout are capable of detecting EoR over a substantial observing window on the sky.

Towards simulating and quantifying the light-cone EoR 21-cm signal

NASA Astrophysics Data System (ADS)

Mondal, Rajesh; Bharadwaj, Somnath; Datta, Kanan K.

2018-02-01

The light-cone (LC) effect causes the Epoch of Reionization (EoR) 21-cm signal T_b (\\hat{n}, ν ) to evolve significantly along the line-of-sight (LoS) direction ν. In the first part of this paper, we present a method to properly incorporate the LC effect in simulations of the EoR 21-cm signal that includes peculiar velocities. Subsequently, we discuss how to quantify the second-order statistics of the EoR 21-cm signal in the presence of the LC effect. We demonstrate that the 3D power spectrum P(k) fails to quantify the entire information because it assumes the signal to be ergodic and periodic, whereas the LC effect breaks these conditions along the LoS. Considering a LC simulation centred at redshift 8 where the mean neutral fraction drops from 0.65 to 0.35 across the box, we find that P(k) misses out ˜ 40 per cent of the information at the two ends of the 17.41 MHz simulation bandwidth. The multifrequency angular power spectrum (MAPS) C_{ℓ}(ν_1,ν_2) quantifies the statistical properties of T_b (\\hat{n}, ν ) without assuming the signal to be ergodic and periodic along the LoS. We expect this to quantify the entire statistical information of the EoR 21-cm signal. We apply MAPS to our LC simulation and present preliminary results for the EoR 21-cm signal.

An extended model for ultrasonic-based enhanced oil recovery with experimental validation.

PubMed

Mohsin, Mohammed; Meribout, Mahmoud

2015-03-01

This paper suggests a new ultrasonic-based enhanced oil recovery (EOR) model for application in oil field reservoirs. The model is modular and consists of an acoustic module and a heat transfer module, where the heat distribution is updated when the temperature rise exceeds 1 °C. The model also considers the main EOR parameters which includes both the geophysical (i.e., porosity, permeability, temperature rise, and fluid viscosity) and acoustical (e.g., acoustic penetration and pressure distribution in various fluids and mediums) properties of the wells. Extended experiments were performed using powerful ultrasonic waves which were applied for different kind of oils & oil saturated core samples. The corresponding results showed a good matching with those obtained from simulations, validating the suggested model to some extent. Hence, a good recovery rate of around 88.2% of original oil in place (OOIP) was obtained after 30 min of continuous generation of ultrasonic waves. This leads to consider the ultrasonic-based EOR as another tangible solution for EOR. This claim is supported further by considering several injection wells where the simulation results indicate that with four (4) injection wells; the recovery rate may increase up-to 96.7% of OOIP. This leads to claim the high potential of ultrasonic-based EOR as compared to the conventional methods. Following this study, the paper also proposes a large scale ultrasonic-based EOR hardware system for installation in oil fields. Copyright © 2014 Elsevier B.V. All rights reserved.

Multiphase flow of miscible liquids: jets and drops

NASA Astrophysics Data System (ADS)

Walker, Travis W.; Logia, Alison N.; Fuller, Gerald G.

2015-05-01

Drops and jets of liquids that are miscible with the surrounding bulk liquid are present in many processes from cleaning surfaces with the aid of liquid soaps to the creation of biocompatible implants for drug delivery. Although the interactions of immiscible drops and jets show similarities to miscible systems, the small, transient interfacial tension associated with miscible systems create distinct outcomes such as intricate droplet shapes and breakup resistant jets. Experiments have been conducted to understand several basic multiphase flow problems involving miscible liquids. Using high-speed imaging of the morphological evolution of the flows, we have been able to show that these processes are controlled by interfacial tensions. Further multiphase flows include investigating miscible jets, which allow the creation of fibers from inelastic materials that are otherwise difficult to process due to capillary breakup. This work shows that stabilization from the diminishing interfacial tensions of the miscible jets allows various elongated morphologies to be formed.

Molecular driving forces behind the tetrahydrofuran–water miscibility gap

DOE PAGES

Smith, Micholas Dean; Mostofian, Barmak; Petridis, Loukas; ...

2016-01-06

The tetrahydrofuran water binary system exhibits an unusual closed-loop miscibility gap (transitions from a miscible regime to an immiscible regime back to another miscible regime as the temperature increases). Here, using all-atom molecular dynamics simulations, we probe the structural and dynamical behavior of the binary system in the temperature regime of this gap at four different mass ratios, and we compare the behavior of bulk water and tetrahydrofuran. The changes in structure and dynamics observed in the simulations indicate that the temperature region associated with the miscibility gap is distinctive. Within the miscibility-gap temperature region, the self diffusion of watermore » is significantly altered and the second virial coefficients (pair interaction strengths) show parabolic-like behavior. Altogether, the results suggest that the gap is the result of differing trends with temperature of minor structural changes, which produces interaction virials with parabolic temperature dependence near the miscibility gap.« less

Lake Charles CCS Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leib, Thomas; Cole, Dan

In late September 2014 development of the Lake Charles Clean Energy (LCCE) Plant was abandoned resulting in termination of Lake Charles Carbon Capture and Sequestration (CCS) Project which was a subset the LCCE Plant. As a result, the project was only funded through Phase 2A (Design) and did not enter Phase 2B (Construction) or Phase 2C (Operations). This report was prepared relying on information prepared and provided by engineering companies which were engaged by Leucadia Energy, LLC to prepare or review Front End Engineering and Design (FEED) for the Lake Charles Clean Energy Project, which includes the Carbon Capture andmore » Sequestration (CCS) Project in Lake Charles, Louisiana. The Lake Charles Carbon Capture and Sequestration (CCS) Project was to be a large-scale industrial CCS project intended to demonstrate advanced technologies that capture and sequester carbon dioxide (CO 2) emissions from industrial sources into underground formations. The Scope of work was divided into two discrete sections; 1) Capture and Compression prepared by the Recipient Leucadia Energy, LLC, and 2) Transport and Sequestration prepared by sub-Recipient Denbury Onshore, LLC. Capture and Compression-The Lake Charles CCS Project Final Technical Report describes the systems and equipment that would be necessary to capture CO 2 generated in a large industrial gasification process and sequester the CO 2 into underground formations. The purpose of each system is defined along with a description of its equipment and operation. Criteria for selection of major equipment are provided and ancillary utilities necessary for safe and reliable operation in compliance with environmental regulations are described. Construction considerations are described including a general arrangement of the CCS process units within the overall gasification project. A cost estimate is provided, delineated by system area with cost breakdown showing equipment, piping and materials, construction labor, engineering, and other costs. The CCS Project Final Technical Report is based on a Front End Engineering and Design (FEED) study prepared by SK E&C, completed in [June] 2014. Subsequently, Fluor Enterprises completed a FEED validation study in mid-September 2014. The design analyses indicated that the FEED package was sufficient and as expected. However, Fluor considered the construction risk based on a stick-build approach to be unacceptable, but construction risk would be substantially mitigated through utilization of modular construction where site labor and schedule uncertainty is minimized. Fluor’s estimate of the overall EPC project cost utilizing the revised construction plan was comparable to SKE&C’s value after reflecting Fluor’s assessment of project scope and risk characteristic. Development was halted upon conclusion of Phase 2A FEED and the project was not constructed.Transport and Sequestration – The overall objective of the pipeline project was to construct a pipeline to transport captured CO 2 from the Lake Charles Clean Energy project to the existing Denbury Green Line and then to the Hastings Field in Southeast Texas to demonstrate effective geologic sequestration of captured CO 2 through commercial EOR operations. The overall objective of the MVA portion of the project was to demonstrate effective geologic sequestration of captured CO 2 through commercial Enhanced Oil Recovery (EOR) operations in order to evaluate costs, operational processes and technical performance. The DOE target for the project was to capture and implement a research MVA program to demonstrate the sequestration through EOR of approximately one million tons of CO 2 per year as an integral component of commercial operations.« less

DEVELOPMENT AND OPTIMIZATION OF GAS-ASSISTED GRAVITY DRAINAGE (GAGD) PROCESS FOR IMPROVED LIGHT OIL RECOVERY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dandina N. Rao; Subhash C. Ayirala; Madhav M. Kulkarni

This report describes the progress of the project ''Development And Optimization of Gas-Assisted Gravity Drainage (GAGD) Process for Improved Light Oil Recovery'' for the duration of the thirteenth project quarter (Oct 1, 2005 to Dec 30, 2005). There are three main tasks in this research project. Task 1 is a scaled physical model study of the GAGD process. Task 2 is further development of a vanishing interfacial tension (VIT) technique for miscibility determination. Task 3 is determination of multiphase displacement characteristics in reservoir rocks. Section I reports experimental work designed to investigate wettability effects of porous medium, on secondary andmore » tertiary mode GAGD performance. The experiments showed a significant improvement of oil recovery in the oil-wet experiments versus the water-wet runs, both in secondary as well as tertiary mode. When comparing experiments conducted in secondary mode to those run in tertiary mode an improvement in oil recovery was also evident. Additionally, this section summarizes progress made with regard to the scaled physical model construction and experimentation. The purpose of building a scaled physical model, which attempts to include various multiphase mechanics and fluid dynamic parameters operational in the field scale, was to incorporate visual verification of the gas front for viscous instabilities, capillary fingering, and stable displacement. Preliminary experimentation suggested that construction of the 2-D model from sintered glass beads was a feasible alternative. During this reporting quarter, several sintered glass mini-models were prepared and some preliminary experiments designed to visualize gas bubble development were completed. In Section II, the gas-oil interfacial tensions measured in decane-CO{sub 2} system at 100 F and live decane consisting of 25 mole% methane, 30 mole% n-butane and 45 mole% n-decane against CO{sub 2} gas at 160 F have been modeled using the Parachor and newly proposed mechanistic Parachor models. In the decane-CO{sub 2} binary system, Parachor model was found to be sufficient for interfacial tension calculations. The predicted miscibility from the Parachor model deviated only by about 2.5% from the measured VIT miscibility. However, in multicomponent live decane-CO{sub 2} system, the performance of the Parachor model was poor, while good match of interfacial tension predictions has been obtained experimentally using the proposed mechanistic Parachor model. The predicted miscibility from the mechanistic Parachor model accurately matched with the measured VIT miscibility in live decane-CO2 system, which indicates the suitability of this model to predict miscibility in complex multicomponent hydrocarbon systems. In the previous reports to the DOE (15323R07, Oct 2004; 15323R08, Jan 2005; 15323R09, Apr 2005; 15323R10, July 2005 and 154323, Oct 2005), the 1-D experimental results from dimensionally scaled GAGD and WAG corefloods were reported for Section III. Additionally, since Section I reports the experimental results from 2-D physical model experiments; this section attempts to extend this 2-D GAGD study to 3-D (4-phase) flow through porous media and evaluate the performance of these processes using reservoir simulation. Section IV includes the technology transfer efforts undertaken during the quarter. This research work resulted in one international paper presentation in Tulsa, OK; one journal publication; three pending abstracts for SCA 2006 Annual Conference and an invitation to present at the Independents Day session at the IOR Symposium 2006.« less

Observation of silicon self-diffusion enhanced by the strain originated from end-of-range defects using isotope multilayers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Isoda, Taiga; Uematsu, Masashi; Itoh, Kohei M., E-mail: kitoh@appi.keio.ac.jp

2015-09-21

Si self-diffusion in the presence of end-of-range (EOR) defects is investigated using {sup nat}Si/{sup 28}Si isotope multilayers. The isotope multilayers were amorphized by Ge ion implantation, and then annealed at 800–950 °C. The behavior of Si self-interstitials is investigated through the {sup 30}Si self-diffusion. The experimental {sup 30}Si profiles show further enhancement of Si self-diffusion at the EOR defect region, in addition to the transient enhanced diffusion via excess Si self-interstitials by EOR defects. To explain this additional enhanced diffusion, we propose a model which takes into account enhanced diffusion by tensile strain originated from EOR defects. The calculation results basedmore » on this model have well reproduced the experimental {sup 30}Si profiles.« less

Sonochemical approaches to enhanced oil recovery.

PubMed

Abramov, Vladimir O; Abramova, Anna V; Bayazitov, Vadim M; Altunina, Lyubov K; Gerasin, Artyom S; Pashin, Dmitriy M; Mason, Timothy J

2015-07-01

Oil production from wells reduces with time and the well becomes uneconomic unless enhanced oil recovery (EOR) methods are applied. There are a number of methods currently available and each has specific advantages and disadvantages depending on conditions. Currently there is a big demand for new or improved technologies in this field, the hope is that these might also be applicable to wells which have already been the subject of EOR. The sonochemical method of EOR is one of the most promising methods and is important in that it can also be applied for the treatment of horizontal wells. The present article reports the theoretical background of the developed sonochemical technology for EOR in horizontal wells; describes the requirements to the equipment needed to embody the technology. The results of the first field tests of the technology are reported. Copyright © 2014 Elsevier B.V. All rights reserved.

Ongoing Relative Performance Evaluation for a CO2 EOR Asset in a Worldwide Peer Group

NASA Astrophysics Data System (ADS)

Zhao, C. F.; Li, X. S.; Wang, G. H.; Li, L.

2017-10-01

Abstract. Operators of a CO2 EOR asset need to know the relative performance level of their asset against its peers. The ongoing relative performance evaluation method is appropriate for this purpose. We first choose 52 CO2 assets around the world as the peer group, and then define the four ranking levels in terms of CO2consumption ratio. Only the final values of CO2consumption ratio for the group are obtained, and therefore cannot be used for an ongoing evaluation during a CO2 EOR asset’s life circle. Consequently, numerical reservoir simulation is employed to quantify the process values corresponding to the four ranking levels. Type curve plots are generated on the basis of the process values and utilized for the ongoing relative performance evaluation of a CO2 EOR asset in China.

Miscibility and Morphology of Poly(lactic ACID)/POLY(Β-HYDROXYBUTYRATE) Blends

NASA Astrophysics Data System (ADS)

Tri Phuong, Nguyen; Guinault, Alain; Sollogoub, Cyrille

2011-01-01

The miscibility and morphology of poly(lactic)acid (PLA)/polyβ-hydroxybutyrate (PHB) prepared by melt blending method were investigated by Fourier transform infrared (FTIR), Differential scanning calorimetry (DSC), melt rheology and scanning electron microscopy (SEM) observations. FTIR and DSC methods present some limits to examine the miscibility state of PLA/PHB blends. This drawback can be overcome with the Cole-Cole method by observing the η" = f(η') curves to confirm the miscibility of semicrystalline PLA/ semicrystalline PHB blends. MEB micrographs of fractured surface of blends were also used to investigate the miscibility of these blends.

Development of an assessment methodology for hydrocarbon recovery potential using carbon dioxide and associated carbon sequestration-Workshop findings

USGS Publications Warehouse

Verma, Mahendra K.; Warwick, Peter D.

2011-01-01

The Energy Independence and Security Act of 2007 (Public Law 110-140) authorized the U.S. Geological Survey (USGS) to conduct a national assessment of geologic storage resources for carbon dioxide (CO2) and requested that the USGS estimate the "potential volumes of oil and gas recoverable by injection and sequestration of industrial carbon dioxide in potential sequestration formations" (121 Stat. 1711). The USGS developed a noneconomic, probability-based methodology to assess the Nation's technically assessable geologic storage resources available for sequestration of CO2 (Brennan and others, 2010) and is currently using the methodology to assess the Nation's CO2 geologic storage resources. Because the USGS has not developed a methodology to assess the potential volumes of technically recoverable hydrocarbons that could be produced by injection and sequestration of CO2, the Geologic Carbon Sequestration project initiated an effort in 2010 to develop a methodology for the assessment of the technically recoverable hydrocarbon potential in the sedimentary basins of the United States using enhanced oil recovery (EOR) techniques with CO2 (CO2-EOR). In collaboration with Stanford University, the USGS hosted a 2-day CO2-EOR workshop in May 2011, attended by 28 experts from academia, natural resource agencies and laboratories of the Federal Government, State and international geologic surveys, and representatives from the oil and gas industry. The geologic and the reservoir engineering and operations working groups formed during the workshop discussed various aspects of geology, reservoir engineering, and operations to make recommendations for the methodology.

Optimizing and Quantifying CO 2 Storage Resource in Saline Formations and Hydrocarbon Reservoirs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bosshart, Nicholas W.; Ayash, Scott C.; Azzolina, Nicholas A.

In an effort to reduce carbon dioxide (CO 2) emissions from large stationary sources, carbon capture and storage (CCS) is being investigated as one approach. This work assesses CO 2 storage resource estimation methods for deep saline formations (DSFs) and hydrocarbon reservoirs undergoing CO 2 enhanced oil recovery (EOR). Project activities were conducted using geologic modeling and simulation to investigate CO 2 storage efficiency. CO 2 storage rates and efficiencies in DSFs classified by interpreted depositional environment were evaluated at the regional scale over a 100-year time frame. A focus was placed on developing results applicable to future widespread commercial-scalemore » CO 2 storage operations in which an array of injection wells may be used to optimize storage in saline formations. The results of this work suggest future investigations of prospective storage resource in closed or semiclosed formations need not have a detailed understanding of the depositional environment of the reservoir to generate meaningful estimates. However, the results of this work also illustrate the relative importance of depositional environment, formation depth, structural geometry, and boundary conditions on the rate of CO 2 storage in these types of systems. CO 2 EOR occupies an important place in the realm of geologic storage of CO 2, as it is likely to be the primary means of geologic CO 2 storage during the early stages of commercial implementation, given the lack of a national policy and the viability of the current business case. This work estimates CO 2 storage efficiency factors using a unique industry database of CO 2 EOR sites and 18 different reservoir simulation models capturing fluvial clastic and shallow shelf carbonate depositional environments for reservoir depths of 1219 and 2438 meters (4000 and 8000 feet) and 7.6-, 20-, and 64-meter (25-, 66,- and 209-foot) pay zones. The results of this work provide practical information that can be used to quantify CO 2 storage resource estimates in oil reservoirs during CO 2 EOR operations (as opposed to storage following depletion) and the uncertainty associated with those estimates.« less

Early post-operative magnetic resonance imaging in glioblastoma: correlation among radiological findings and overall survival in 60 patients.

PubMed

Majós, Carles; Cos, Mònica; Castañer, Sara; Gil, Miguel; Plans, Gerard; Lucas, Anna; Bruna, Jordi; Aguilera, Carles

2016-04-01

To evaluate early post-operative magnetic resonance (EPMR) as a prognostic tool after resection of glioblastoma. Sixty EPMR examinations were evaluated for perioperative infarct, tumour growth between diagnosis and EPMR, contrast enhancement pattern, and extent of resection (EOR). The EOR was approached with the subjective evaluation of radiologists and by quantifying volumes. These parameters were tested as predictors of survival using the Kaplan-Meier method. Contrast enhancement was found in 59 patients (59/60; 98 %). Showing a thin-linear pattern of enhancement was the most favourable finding. Patients with this pattern survived longer than patients with thick-linear (median overall survival (OS) thin-linear=609 days; thick-linear=432 days; P = .023) or nodular (median OS = 318 days; P = .001) enhancements. The subjective evaluation of the EOR performed better than its quantification. Patients survived longer when resection was total (median OS total resection=609 days; subtotal=371 days; P = .001). When resection was subtotal, patients survived longer if it was superior to 95 % (median OS resection superior to 95 %=559 days; inferior to 95 %=256 days; P = .034). EPMR provides valuable prognostic information after surgical resection of glioblastomas. A thin-linear pattern of contrast enhancement is the most favourable finding. Further prognostic stratification may be obtained by assessing the EOR. • Some kind of contrast enhancement may be found in most EPMR examinations. • Thin-linear enhancements in the EPMR may be considered benign findings. • The EOR evaluated in the EPMR may stratify prognostic groups of patients. • The subjective evaluation of the EOR performs slightly better than its quantification.

Impact of Three-Phase Relative Permeability and Hysteresis Models on Forecasts of Storage Associated With CO2-EOR

NASA Astrophysics Data System (ADS)

Jia, Wei; McPherson, Brian; Pan, Feng; Dai, Zhenxue; Moodie, Nathan; Xiao, Ting

2018-02-01

Geological CO2 sequestration in conjunction with enhanced oil recovery (CO2-EOR) includes complex multiphase flow processes compared to CO2 storage in deep saline aquifers. Two of the most important factors affecting multiphase flow in CO2-EOR are three-phase relative permeability and associated hysteresis, both of which are difficult to measure and are usually represented by numerical interpolation models. The purpose of this study is to improve understanding of (1) the relative impacts of different three-phase relative permeability models and hysteresis models on CO2 trapping mechanisms, and (2) uncertainty associated with these two factors. Four different three-phase relative permeability models and three hysteresis models were applied to simulations of an active CO2-EOR site, the SACROC unit located in western Texas. To eliminate possible bias of deterministic parameters, we utilized a sequential Gaussian simulation technique to generate 50 realizations to describe heterogeneity of porosity and permeability, based on data obtained from well logs and seismic survey. Simulation results of forecasted CO2 storage suggested that (1) the choice of three-phase relative permeability model and hysteresis model led to noticeable impacts on forecasted CO2 sequestration capacity; (2) impacts of three-phase relative permeability models and hysteresis models on CO2 trapping are small during the CO2-EOR injection period, and increase during the post-EOR CO2 injection period; (3) the specific choice of hysteresis model is more important relative to the choice of three-phase relative permeability model; and (4) using the recommended three-phase WAG (Water-Alternating-Gas) hysteresis model may increase the impact of three-phase relative permeability models and uncertainty due to heterogeneity.

Three-Hand Endoscopic Endonasal Transsphenoidal Surgery: Experience With an Anatomy-Preserving Mononostril Approach Technique.

PubMed

Eseonu, Chikezie I; ReFaey, Karim; Pamias-Portalatin, Eva; Asensio, Javier; Garcia, Oscar; Boahene, Kofi D; Quiñones-Hinojosa, Alfredo

2018-02-01

Variations on the endoscopic transsphenoidal approach present unique surgical techniques that have unique effects on surgical outcomes, extent of resection (EOR), and anatomical complications. To analyze the learning curve and perioperative outcomes of the 3-hand endoscopic endonasal mononostril transsphenoidal technique. Prospective case series and retrospective data analysis of patients who were treated with the 3-hand transsphenoidal technique between January 2007 and May 2015 by a single neurosurgeon. Patient characteristics, preoperative presentation, tumor characteristics, operative times, learning curve, and postoperative outcomes were analyzed. Volumetric EOR was evaluated, and a logistic regression analysis was used to assess predictors of EOR. Two hundred seventy-five patients underwent an endoscopic transsphenoidal surgery using the 3-hand technique. One hundred eighteen patients in the early group had surgery between 2007 and 2010, while 157 patients in the late group had surgery between 2011 and 2015. Operative time was significantly shorter in the late group (161.6 min) compared to the early group (211.3 min, P = .001). Both cohorts had similar EOR (early group 84.6% vs late group 85.5%, P = .846) and postoperative outcomes. The learning curve showed that it took 54 cases to achieve operative proficiency with the 3-handed technique. Multivariate modeling suggested that prior resections and preoperative tumor size are important predictors for EOR. We describe a 3-hand, mononostril endoscopic transsphenoidal technique performed by a single neurosurgeon that has minimal anatomic distortion and postoperative complications. During the learning curve of this technique, operative time can significantly decrease, while EOR, postoperative outcomes, and complications are not jeopardized. Copyright © 2017 by the Congress of Neurological Surgeons

Nanoparticle-stabilized CO₂ foam for CO₂ EOR application

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Ning; Lee, Robert; Yu, Jianjia

The purpose of this project was to develop nanoparticle-stabilized CO₂ foam for CO₂ -EOR application, in which nanoparticles instead of surfactants are used for stabilizing CO₂ foam to improve the CO₂ sweep efficiency and increase oil recovery. The studies included: (1) investigation of CO₂ foam generation nanoparticles, such as silica nanoparticles, and the effects of particle concentration and surface properties, CO₂/brine ratio, brine salinity, pressure, and temperature on foam generation and foam stability; (2) coreflooding tests to understand the nanoparticle-stabilized CO₂ foam for waterflooded residual oil recovery, which include: oil-free coreflooding experiments with nanoparticle-stabilized CO₂ foam to understand the transportationmore » of nanoparticles through the core; measurements of foam stability and CO₂ sweep efficiency under reservoir conditions to investigate temperature and pressure effects on the foam performance and oil recovery as well as the sweep efficiency in different core samples with different rock properties; and (3) long-term coreflooding experiments with the nanoparticle- stabilized CO₂ foam for residual oil recovery. Finally, the technical and economical feasibility of this technology was evaluated.« less

Experimental study on electromagnetic-assisted ZnO nanofluid flooding for enhanced oil recovery (EOR)

PubMed Central

Ahmad Latiff, Noor Rasyada; Alnarabiji, Mohamad Sahban

2018-01-01

Recently, nano-EOR has emerged as a new frontier for improved and enhanced oil recovery (IOR & EOR). Despite their benefits, the nanoparticles tend to agglomerate at reservoir conditions which cause their detachment from the oil/water interface, and are consequently retained rather than transported through a porous medium. Dielectric nanoparticles including ZnO have been proposed to be a good replacement for EOR due to their high melting point and thermal properties. But more importantly, these particles can be polarized under electromagnetic (EM) irradiation, which provides an innovative smart Nano-EOR process denoted as EM-Assisted Nano-EOR. In this study, parameters involved in the oil recovery mechanism under EM waves, such as reducing mobility ratio, lowering interfacial tensions (IFT) and altering wettability were investigated. Two-phase displacement experiments were performed in sandpacks under the water-wet condition at 95°C, with permeability in the range of 265–300 mD. A crude oil from Tapis oil field was employed; while ZnO nanofluids of two different particle sizes (55.7 and 117.1 nm) were prepared using 0.1 wt. % nanoparticles that dispersed into brine (3 wt. % NaCl) along with SDBS as a dispersant. In each flooding scheme, three injection sequential scenarios have been conducted: (i) brine flooding as a secondary process, (ii) surfactant/nano/EM-assisted nano flooding, and (iii) second brine flooding to flush nanoparticles. Compare with surfactant flooding (2% original oil in place/OOIP) as tertiary recovery, nano flooding almost reaches 8.5–10.2% of OOIP. On the other hand, EM-assisted nano flooding provides an incremental oil recovery of approximately 9–10.4% of OOIP. By evaluating the contact angle and interfacial tension, it was established that the degree of IFT reduction plays a governing role in the oil displacement mechanism via nano-EOR, compare to mobility ratio. These results reveal a promising way to employ water-based ZnO nanofluid for enhanced oil recovery purposes at a relatively high reservoir temperature. PMID:29489897

Experimental study on electromagnetic-assisted ZnO nanofluid flooding for enhanced oil recovery (EOR).

PubMed

Adil, Muhammad; Lee, Keanchuan; Mohd Zaid, Hasnah; Ahmad Latiff, Noor Rasyada; Alnarabiji, Mohamad Sahban

2018-01-01

Recently, nano-EOR has emerged as a new frontier for improved and enhanced oil recovery (IOR & EOR). Despite their benefits, the nanoparticles tend to agglomerate at reservoir conditions which cause their detachment from the oil/water interface, and are consequently retained rather than transported through a porous medium. Dielectric nanoparticles including ZnO have been proposed to be a good replacement for EOR due to their high melting point and thermal properties. But more importantly, these particles can be polarized under electromagnetic (EM) irradiation, which provides an innovative smart Nano-EOR process denoted as EM-Assisted Nano-EOR. In this study, parameters involved in the oil recovery mechanism under EM waves, such as reducing mobility ratio, lowering interfacial tensions (IFT) and altering wettability were investigated. Two-phase displacement experiments were performed in sandpacks under the water-wet condition at 95°C, with permeability in the range of 265-300 mD. A crude oil from Tapis oil field was employed; while ZnO nanofluids of two different particle sizes (55.7 and 117.1 nm) were prepared using 0.1 wt. % nanoparticles that dispersed into brine (3 wt. % NaCl) along with SDBS as a dispersant. In each flooding scheme, three injection sequential scenarios have been conducted: (i) brine flooding as a secondary process, (ii) surfactant/nano/EM-assisted nano flooding, and (iii) second brine flooding to flush nanoparticles. Compare with surfactant flooding (2% original oil in place/OOIP) as tertiary recovery, nano flooding almost reaches 8.5-10.2% of OOIP. On the other hand, EM-assisted nano flooding provides an incremental oil recovery of approximately 9-10.4% of OOIP. By evaluating the contact angle and interfacial tension, it was established that the degree of IFT reduction plays a governing role in the oil displacement mechanism via nano-EOR, compare to mobility ratio. These results reveal a promising way to employ water-based ZnO nanofluid for enhanced oil recovery purposes at a relatively high reservoir temperature.

Comparative antibacterial effects of moxifloxacin and levofloxacin on Streptococcus pneumoniae strains with defined mechanisms of resistance: impact of bacterial inoculum.

PubMed

Bowker, K E; Garvey, M I; Noel, A R; Tomaselli, S G; Macgowan, A P

2013-05-01

We aim to further define the impact of the mechanism of fluoroquinolone resistance and inoculum load on the pharmacodynamic effects of levofloxacin and moxifloxacin on Streptococcus pneumoniae. The antibacterial effects of and emergence of resistance (EoR) to moxifloxacin (400 mg once daily) or levofloxacin (750 mg once daily or 500 mg twice daily) were compared using five S. pneumoniae strains containing no known resistance mechanisms, efflux resistance mechanisms, a parC mutation or parC and gyrA mutations, at high (10(8) cfu/mL) and low (10(6) cfu/mL) inocula. An in vitro pharmacokinetic model was used and simulations were performed over 96 h. After drug exposure, isolates were tested for the presence of efflux pumps and mutations in the quinolone resistance-determining regions. A high inoculum diminished the antibacterial effect of moxifloxacin and levofloxacin. Levofloxacin at both dosages produced EoR with all strains. Levofloxacin regimens with AUC/MIC ratios <100 produced EoR. Moxifloxacin produced EoR with the parC strain only. Levofloxacin dosing regimens with low AUC/MIC ratios select for efflux pump overexpression, leading to fluoroquinolone resistance. Levofloxacin dosing may select for gyrA mutations, inducing moxifloxacin resistance. These data confirm that a fluoroquinolone AUC/MIC ratio of >100 is required for prevention of EoR.

Prediction of solubility parameters and miscibility of pharmaceutical compounds by molecular dynamics simulations.

PubMed

Gupta, Jasmine; Nunes, Cletus; Vyas, Shyam; Jonnalagadda, Sriramakamal

2011-03-10

The objectives of this study were (i) to develop a computational model based on molecular dynamics technique to predict the miscibility of indomethacin in carriers (polyethylene oxide, glucose, and sucrose) and (ii) to experimentally verify the in silico predictions by characterizing the drug-carrier mixtures using thermoanalytical techniques. Molecular dynamics (MD) simulations were performed using the COMPASS force field, and the cohesive energy density and the solubility parameters were determined for the model compounds. The magnitude of difference in the solubility parameters of drug and carrier is indicative of their miscibility. The MD simulations predicted indomethacin to be miscible with polyethylene oxide and to be borderline miscible with sucrose and immiscible with glucose. The solubility parameter values obtained using the MD simulations values were in reasonable agreement with those calculated using group contribution methods. Differential scanning calorimetry showed melting point depression of polyethylene oxide with increasing levels of indomethacin accompanied by peak broadening, confirming miscibility. In contrast, thermal analysis of blends of indomethacin with sucrose and glucose verified general immiscibility. The findings demonstrate that molecular modeling is a powerful technique for determining the solubility parameters and predicting miscibility of pharmaceutical compounds. © 2011 American Chemical Society

Development of an In Situ Biosurfactant Production Technology for Enhanced Oil Recovery

DOE Office of Scientific and Technical Information (OSTI.GOV)

M.J. McInerney; R.M. Knapp; Kathleen Duncan

The long-term economic potential for enhanced oil recovery (EOR) is large with more than 300 billion barrels of oil remaining in domestic reservoirs after conventional technologies reach their economic limit. Actual EOR production in the United States has never been very large, less than 10% of the total U. S. production even though a number of economic incentives have been used to stimulate the development and application of EOR processes. The U.S. DOE Reservoir Data Base contains more than 600 reservoirs with over 12 billion barrels of unrecoverable oil that are potential targets for microbially enhanced oil recovery (MEOR). Ifmore » MEOR could be successfully applied to reduce the residual oil saturation by 10% in a quarter of these reservoirs, more than 300 million barrels of oil could be added to the U.S. oil reserve. This would stimulate oil production from domestic reservoirs and reduce our nation's dependence on foreign imports. Laboratory studies have shown that detergent-like molecules called biosurfactants, which are produced by microorganisms, are very effective in mobilizing entrapped oil from model test systems. The biosurfactants are effective at very low concentrations. Given the promising laboratory results, it is important to determine the efficacy of using biosurfactants in actual field applications. The goal of this project is to move biosurfactant-mediated oil recovery from laboratory investigations to actual field applications. In order to meet this goal, several important questions must be answered. First, it is critical to know whether biosurfactant-producing microbes are present in oil formations. If they are present, then it will be important to know whether a nutrient regime can be devised to stimulate their growth and activity in the reservoir. If biosurfactant producers are not present, then a suitable strain must be obtained that can be injected into oil reservoirs. We were successful in answering all three questions. The specific objectives of the project were (1) to determine the prevalence of biosurfactant producers in oil reservoirs, and (2) to develop a nutrient regime that would stimulate biosurfactant production in the oil reservoir.« less

Life cycle assessment of carbon capture and utilization from ammonia process in Mexico.

PubMed

Morales Mora, M A; Vergara, C Pretelín; Leiva, M A; Martínez Delgadillo, S A; Rosa-Domínguez, E R

2016-12-01

Post-combustion CO 2 capture (PCC) of flue gas from an ammonia plant (AP) and the environmental performance of the carbon capture utilization (CCU) technology for greenhouse gas (GHG) emissions to an enhanced oil recovery (EOR) system in Mexico was performed as case study. The process simulations (PS) and life cycle assessment (LCA) were used as supporting tools to quantify the CO 2 capture and their environmental impacts, respectively. Two scenarios were considered: 1) the AP with its shift and CO 2 removal unit and 2) Scenario 1 plus PCC of the flue gas from the AP primary reformer (AP-2CO 2 ) and the global warming (GW) impact. Also, the GW of the whole of a CO 2 -EOR project, from these two streams of captured CO 2 , was evaluated. Results show that 372,426 tCO 2 /year can be PCC from the flue gas of the primary reformer and 480,000 tons/y of capacity from the AP. The energy requirement for solvent regeneration is estimated to be 2.8 MJ/kgCO 2 or a GW impact of 0.22 kgCO 2e /kgCO 2 captured. GW performances are 297.6 kgCO 2e emitted/barrel (bbl) for scenario one, and 106.5 kgCO 2e emitted/bbl for the second. The net emissions, in scenario one, were 0.52 tCO 2e /bbl and 0.33 tCO 2e /bbl in scenario two. Based on PS, this study could be used to evaluate the potential of CO 2 capture of 4080 t/d of 4 ammonia plants. The integration of PS-LCA to a PCC study allows the applicability as methodological framework for the development of a cluster of projects in which of CO 2 could be recycled back to fuel, chemical, petrochemical products or for enhanced oil recovery (EOR). With AP-2CO 2, "CO 2 emission free" ammonia production could be achieved. Copyright © 2016 Elsevier Ltd. All rights reserved.

Polarization leakage in epoch of reionization windows - III. Wide-field effects of narrow-field arrays

NASA Astrophysics Data System (ADS)

Asad, K. M. B.; Koopmans, L. V. E.; Jelić, V.; de Bruyn, A. G.; Pandey, V. N.; Gehlot, B. K.

2018-05-01

Leakage of polarized Galactic diffuse emission into total intensity can potentially mimic the 21-cm signal coming from the epoch of reionization (EoR), as both of them might have fluctuating spectral structure. Although we are sensitive to the EoR signal only in small fields of view, chromatic side-lobes from further away can contaminate the inner region. Here, we explore the effects of leakage into the `EoR window' of the cylindrically averaged power spectra (PS) within wide fields of view using both observation and simulation of the 3C196 and North Celestial Pole (NCP) fields, two observing fields of the LOFAR-EoR project. We present the polarization PS of two one-night observations of the two fields and find that the NCP field has higher fluctuations along frequency, and consequently exhibits more power at high-k∥ that could potentially leak to Stokes I. Subsequently, we simulate LOFAR observations of Galactic diffuse polarized emission based on a model to assess what fraction of polarized power leaks into Stokes I because of the primary beam. We find that the rms fractional leakage over the instrumental k-space is 0.35 {per cent} in the 3C196 field and 0.27 {per cent} in the NCP field, and it does not change significantly within the diameters of 15°, 9°, and 4°. Based on the observed PS and simulated fractional leakage, we show that a similar level of leakage into Stokes I is expected in the 3C196 and NCP fields, and the leakage can be considered to be a bias in the PS.

Application of film-casting technique to investigate drug-polymer miscibility in solid dispersion and hot-melt extrudate.

PubMed

Parikh, Tapan; Gupta, Simerdeep Singh; Meena, Anuprabha K; Vitez, Imre; Mahajan, Nidhi; Serajuddin, Abu T M

2015-07-01

Determination of drug-polymer miscibility is critical for successful development of solid dispersions. This report details a practical method to predict miscibility and physical stability of drug with various polymers in solid dispersion and, especially, in melt extrudates by applying a film-casting technique. Mixtures of itraconazole (ITZ) with hydroxypropylmethylcellulose phthalate (HPMCP), Kollidon(®) VA 64, Eudragit(®) E PO, and Soluplus(®) were film-casted, exposed to 40°C/75% RH for 1 month and then analyzed using differential scanning calorimetry (DSC), powder X-ray diffractometry, and polarized light microscopy (PLM). ITZ had the highest miscibility with HPMCP, being miscible at drug to polymer ratio of 6:4 (w/w). There was a downward trend of lower miscibility with Soluplus(®) (miscible at 3:7, w/w, and a few microcrystals present at 4:6, w/w), Kollidon(®) VA 64 (2:8, w/w) and Eudragit(®) E PO (<1:9, w/w). PLM was found more sensitive to detect drug crystallization than DSC and powder X-ray diffractometry. There was general correlation between results of film casting and hot-melt extrusion (HME) using a twin screw extruder. For ITZ-Soluplus(®) mixtures, HME at 4:6 (w/w) resulted in a single phase, whereas drug crystallization was observed at higher drug load. HME of ITZ-Kollidon(®) VA 64 mixtures also correlated well with the miscibility predicted by film casting. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

Ir catalysts: Preventing CH3COOH formation in ethanol oxidation

NASA Astrophysics Data System (ADS)

Miao, Bei; Wu, Zhipeng; Xu, Han; Zhang, Minhua; Chen, Yifei; Wang, Lichang

2017-11-01

Current catalysts used for ethanol oxidation reaction (EOR) cannot effectively prevent CH3COOH formation, and thus become a major hindrance for direct ethanol fuel cell applications. We report an Ir catalyst that shows great promise for a complete EOR based on density functional theory calculations using PBE functional. The reaction barrier on Ir(1 0 0) was found to be 2.10 eV for CH3COOH formation, which is much higher than currently used Pd and Pt, and 0.57 eV for Csbnd C bond cleavage in CHCO species, which are comparable to Pd and Pt. The result suggests future directions for studying optimal complete EOR catalysts.

Role of extent of resection on quality of life in patients with newly diagnosed GBM.

PubMed

Choudry, Usama Khalid; Shaikh, Huzaifa Ismail; Nisar, Areeba; Khan, Saad Akhtar; Shamim, Muhammad Shahzad

2018-01-01

Glioblastomas known for their adverse outcomes are most reportedly managed by surgical resection. Studies on the impact of (Extent of Resection) EOR against Quality of Life (QOL) are very limited. We have collected data from recent studies in this review to extract a general consensus among the neurosurgeons regarding the EOR. Key parameters like functional independence, neurocognitive improvements and global health status have been explored in the context of QOL. The currently available data suggests that an increased EOR may help improve QOL in GBM patients. With the help of recent advancements it may be possible to attain a better extent of resection while operating on GBMs.

Monte Carlo simulation of star/linear and star/star blends with chemically identical monomers

NASA Astrophysics Data System (ADS)

Theodorakis, P. E.; Avgeropoulos, A.; Freire, J. J.; Kosmas, M.; Vlahos, C.

2007-11-01

The effects of chain size and architectural asymmetry on the miscibility of blends with chemically identical monomers, differing only in their molecular weight and architecture, are studied via Monte Carlo simulation by using the bond fluctuation model. Namely, we consider blends composed of linear/linear, star/linear and star/star chains. We found that linear/linear blends are more miscible than the corresponding star/star mixtures. In star/linear blends, the increase in the volume fraction of the star chains increases the miscibility. For both star/linear and star/star blends, the miscibility decreases with the increase in star functionality. When we increase the molecular weight of linear chains of star/linear mixtures the miscibility decreases. Our findings are compared with recent analytical and experimental results.

Drop impact onto a thin film: Miscibility effect

NASA Astrophysics Data System (ADS)

Chen, Ningli; Chen, H.; Amirfazli, A.

2017-09-01

In this work a systematic experimental study was performed to understand the process of liquid drop impact onto a thin film made of a different liquid from drop. The drop and film liquids can be miscible or immiscible. Three general outcomes of deposition, crown formation without splashing, and splashing, were observed in the advancing phase of the drop impact onto a solid surface covered by either a miscible or an immiscible thin film. However, for a miscible film, a larger Weber number and film thickness are needed for the formation of a crown and splashing comparing with immiscible cases. The advancing phase of drop impact onto a thin immiscible film with a large viscosity is similar to that of drop impact onto a dry surface; for a miscible film viscous film, the behavior is far from that of a dry surface. The behavior of liquid lamella in the receding phase of drop impact onto a thin miscible film is reported for the first time. The results show that immiscibility is not a necessary condition for the existence of a receding phase. The existence of a receding phase is highly dependent on the interfacial tension between the drop and the film. The miscibility can significantly affect the receding morphology as it will cause mixing of the two liquids.

Transient Interfacial Phenomena in Miscible Polymer Systems (TIPMPS)

NASA Technical Reports Server (NTRS)

Pojman, John A.; Bessonov, Nicholas; Volpert, Vitaly; Wilke, Hermann

2003-01-01

Almost one hundred years ago Korteweg published a theory of how stresses could be induced in miscible fluids by concentration gradients, causing phenomena that would appear to be the same as with immiscible fluids. Miscible fluids could manifest a transient or effective interfacial tension (EIT). To this day, there has been no definitive experiment to confirm Korteweg's model but numerous fascinating and suggestive experiments have been reported. The goal of TIPMPS is to answer the question: Can concentration and temperature gradients in miscible materials induce stresses that cause convection? Many polymer processes involving miscible monomer and polymer systems could be affected by fluid flow and so this work could help understand miscible polymer processing, not only in microgravity, but also on earth. Demonstrating the existence of this phenomenon in miscible fluids will open up a new area of study for materials science. The science objectives of TIPMPS are: (1) Determine if convection can be induced by variation of the width of a miscible interface; (2) Determine if convection can be induced by variation of temperature along a miscible interface; (3) Determine if convection can be induced by variation of conversion along a miscible interface An interface between two miscible fluids can best be created via a spatially-selective photopolymerization of dodecyl acrylate with a photoinitiator, which allows the creation of precise and accurate concentration gradients between polymer and monomer. Optical techniques will be used to measure the refractive index variation caused by the resultant temperature and concentration fields. The viscosity of the polymer will be measured from the increase in the fluorescence of pyrene. Because the large concentration and temperature gradients cause buoyancy-driven convection that prevents the observation of the predicted flows, the experiment must be done in microgravity. In this report, we will consider our efforts to estimate the square gradient parameter, k, and our use of the estimates in modeling of the planned TIPMPS experiments. We developed a model consisting of the heat and diffusion equations with convective terms and of the Navier-Stokes equations with an additional volume force written in the form of the Korteweg stresses arising from nonlocal interaction in the fluid. The fluid's viscosity dependence on polymer conversion and temperature was taken from measurements of poly(dodecyl acrylate). Numerical modeling demonstrated that significant flows would arise for conditions corresponding to the planned experiments.

CONSTRAINING POLARIZED FOREGROUNDS FOR EoR EXPERIMENTS. I. 2D POWER SPECTRA FROM THE PAPER-32 IMAGING ARRAY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kohn, S. A.; Aguirre, J. E.; Moore, D. F.

2016-06-01

Current generation low-frequency interferometers constructed with the objective of detecting the high-redshift 21 cm background aim to generate power spectra of the brightness temperature contrast of neutral hydrogen in primordial intergalactic medium. Two-dimensional (2D) power spectra (power in Fourier modes parallel and perpendicular to the line of sight) that formed from interferometric visibilities have been shown to delineate a boundary between spectrally smooth foregrounds (known as the wedge ) and spectrally structured 21 cm background emission (the EoR window ). However, polarized foregrounds are known to possess spectral structure due to Faraday rotation, which can leak into the EoR window.more » In this work we create and analyze 2D power spectra from the PAPER-32 imaging array in Stokes I, Q, U, and V. These allow us to observe and diagnose systematic effects in our calibration at high signal-to-noise within the Fourier space most relevant to EoR experiments. We observe well-defined windows in the Stokes visibilities, with Stokes Q, U, and V power spectra sharing a similar wedge shape to that seen in Stokes I. With modest polarization calibration, we see no evidence that polarization calibration errors move power outside the wedge in any Stokes visibility to the noise levels attained. Deeper integrations will be required to confirm that this behavior persists to the depth required for EoR detection.« less

National Land Imaging Requirements (NLIR) Pilot Project summary report: summary of moderate resolution imaging user requirements

USGS Publications Warehouse

Vadnais, Carolyn; Stensaas, Gregory

2014-01-01

Under the National Land Imaging Requirements (NLIR) Project, the U.S. Geological Survey (USGS) is developing a functional capability to obtain, characterize, manage, maintain and prioritize all Earth observing (EO) land remote sensing user requirements. The goal is a better understanding of community needs that can be supported with land remote sensing resources, and a means to match needs with appropriate solutions in an effective and efficient way. The NLIR Project is composed of two components. The first component is focused on the development of the Earth Observation Requirements Evaluation System (EORES) to capture, store and analyze user requirements, whereas, the second component is the mechanism and processes to elicit and document the user requirements that will populate the EORES. To develop the second component, the requirements elicitation methodology was exercised and refined through a pilot project conducted from June to September 2013. The pilot project focused specifically on applications and user requirements for moderate resolution imagery (5–120 meter resolution) as the test case for requirements development. The purpose of this summary report is to provide a high-level overview of the requirements elicitation process that was exercised through the pilot project and an early analysis of the moderate resolution imaging user requirements acquired to date to support ongoing USGS sustainable land imaging study needs. The pilot project engaged a limited set of Federal Government users from the operational and research communities and therefore the information captured represents only a subset of all land imaging user requirements. However, based on a comparison of results, trends, and analysis, the pilot captured a strong baseline of typical applications areas and user needs for moderate resolution imagery. Because these results are preliminary and represent only a sample of users and application areas, the information from this report should only be used to indicate general user needs for the applications covered. Users of the information are cautioned that use of specific numeric results may be inappropriate without additional research. Any information used or cited from this report should specifically be cited as preliminary findings.

Epoch of reionization window. II. Statistical methods for foreground wedge reduction

NASA Astrophysics Data System (ADS)

Liu, Adrian; Parsons, Aaron R.; Trott, Cathryn M.

2014-07-01

For there to be a successful measurement of the 21 cm epoch of reionization (EoR) power spectrum, it is crucial that strong foreground contaminants be robustly suppressed. These foregrounds come from a variety of sources (such as Galactic synchrotron emission and extragalactic point sources), but almost all share the property of being spectrally smooth and, when viewed through the chromatic response of an interferometer, occupy a signature "wedge" region in cylindrical k⊥k∥ Fourier space. The complement of the foreground wedge is termed the "EoR window" and is expected to be mostly foreground-free, allowing clean measurements of the power spectrum. This paper is a sequel to a previous paper that established a rigorous mathematical framework for describing the foreground wedge and the EoR window. Here, we use our framework to explore statistical methods by which the EoR window can be enlarged, thereby increasing the sensitivity of a power spectrum measurement. We adapt the Feldman-Kaiser-Peacock approximation (commonly used in galaxy surveys) for 21 cm cosmology and also compare the optimal quadratic estimator to simpler estimators that ignore covariances between different Fourier modes. The optimal quadratic estimator is found to suppress foregrounds by an extra factor of ˜105 in power at the peripheries of the EoR window, boosting the detection of the cosmological signal from 12σ to 50σ at the midpoint of reionization in our fiducial models. If numerical issues can be finessed, decorrelation techniques allow the EoR window to be further enlarged, enabling measurements to be made deep within the foreground wedge. These techniques do not assume that foreground is Gaussian distributed, and we additionally prove that a final round of foreground subtraction can be performed after decorrelation in a way that is guaranteed to have no cosmological signal loss.

DEVELOPMENT AND OPTIMIZATION OF GAS-ASSISTED GRAVITY DRAINAGE (GAGD) PROCESS FOR IMPROVED LIGHT OIL RECOVERY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dandina N. Rao

This is the first Annual Technical Progress Report being submitted to the U. S. Department of Energy on the work performed under the Cooperative Agreement DE-FC26-02NT15323. This report follows two other progress reports submitted to U.S. DOE during the first year of the project: The first in April 2003 for the project period from October 1, 2002 to March 31, 2003, and the second in July 2003 for the period April 1, 2003 to June 30, 2003. Although the present Annual Report covers the first year of the project from October 1, 2002 to September 30, 2003, its contents reflectmore » mainly the work performed in the last quarter (July-September, 2003) since the work performed during the first three quarters has been reported in detail in the two earlier reports. The main objective of the project is to develop a new gas-injection enhanced oil recovery process to recover the oil trapped in reservoirs subsequent to primary and/or secondary recovery operations. The project is divided into three main tasks. Task 1 involves the design and development of a scaled physical model. Task 2 consists of further development of the vanishing interfacial tension (VIT) technique for miscibility determination. Task 3 involves the determination of multiphase displacement characteristics in reservoir rocks. Each technical progress report, including this one, reports on the progress made in each of these tasks during the reporting period. Section I covers the scaled physical model study. A survey of literature in related areas has been conducted. Test apparatus has been under construction throughout the reporting period. A bead-pack visual model, liquid injection system, and an image analysis system have been completed and used for preliminary experiments. Experimental runs with decane and paraffin oil have been conducted in the bead pack model. The results indicate the need for modifications in the apparatus, which are currently underway. A bundle of capillary tube model has been considered and formulated aiming to reveal the interplay of the viscous, interfacial and gravity forces and to predict the gravity drainage performance. Scaling criteria for the scaled physical model design have been proposed based on an inspectional analysis. In Section II, equation of state (EOS) calculations were extended to study the effect of different tuning parameters on MMP for two reservoir crude oils of Rainbow Keg River and Terra Nova. This study indicates that tuning of EOS may not always be advisable for miscibility determination. Comparison of IFT measurements for benzene in water, ethanol mixtures with the solubility data from the literature showed that a strong mutual relationship between these two thermodynamic properties exists. These preliminary experiments indicate applicability of the new vanishing interfacial tension (VIT) technique to determine miscibility of ternary liquid systems. The VIT experimental apparatus is under construction with considerations of expanded capacity of using equilibrated fluids and a new provision for low IFT measurement in gas-oil systems. In Section III, recommendations in the previous progress reports have been investigated in this reporting period. WAG coreflood experiments suggest the use of ''Hybrid''-WAG type floods for improved CO{sub 2} utilization factors and recoveries. The effect of saturating the injection water with CO{sub 2} for core-floods has been investigated further in this quarter. Miscible WAG floods using CO{sub 2} saturated brine showed higher recoveries (89.2% ROIP) compared to miscible WAG floods using normal brine (72.5%). Higher tertiary recovery factors (TRF) were also observed for WAG floods using CO{sub 2} saturated brine due to improved mobility ratio and availability of CO{sub 2}. Continued experimentation for evaluation of both, ''Hybrid''-WAG and gravity stable type displacements, in Berea sandstone cores using synthetic as well as real reservoir fluids are planned for the next quarter.« less

4-D High-Resolution Seismic Reflection Monitoring of Miscible CO2 Injected into a Carbonate Reservoir

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richard D. Miller; Abdelmoneam E. Raef; Alan P. Byrnes

2007-06-30

The objective of this research project was to acquire, process, and interpret multiple high-resolution 3-D compressional wave and 2-D, 2-C shear wave seismic data in the hopes of observing changes in fluid characteristics in an oil field before, during, and after the miscible carbon dioxide (CO{sub 2}) flood that began around December 1, 2003, as part of the DOE-sponsored Class Revisit Project (DOE No.DE-AC26-00BC15124). Unique and key to this imaging activity is the high-resolution nature of the seismic data, minimal deployment design, and the temporal sampling throughout the flood. The 900-m-deep test reservoir is located in central Kansas oomoldic limestonesmore » of the Lansing-Kansas City Group, deposited on a shallow marine shelf in Pennsylvanian time. After 30 months of seismic monitoring, one baseline and eight monitor surveys clearly detected changes that appear consistent with movement of CO{sub 2} as modeled with fluid simulators and observed in production data. Attribute analysis was a very useful tool in enhancing changes in seismic character present, but difficult to interpret on time amplitude slices. Lessons learned from and tools/techniques developed during this project will allow high-resolution seismic imaging to be routinely applied to many CO{sub 2} injection programs in a large percentage of shallow carbonate oil fields in the midcontinent.« less

CO 2 Sequestration and Enhanced Oil Recovery at Depleted Oil/Gas Reservoirs

DOE PAGES

Dai, Zhenxue; Viswanathan, Hari; Xiao, Ting; ...

2017-08-18

This study presents a quantitative evaluation of the operational and technical risks of an active CO 2-EOR project. A set of risk factor metrics is defined to post-process the Monte Carlo (MC) simulations for statistical analysis. The risk factors are expressed as measurable quantities that can be used to gain insight into project risk (e.g. environmental and economic risks) without the need to generate a rigorous consequence structure, which include (a) CO 2 injection rate, (b) net CO 2 injection rate, (c) cumulative CO 2 storage, (d) cumulative water injection, (e) oil production rate, (f) cumulative oil production, (g) cumulativemore » CH 4 production, and (h) CO 2 breakthrough time. The Morrow reservoir at the Farnsworth Unit (FWU) site, Texas, is used as an example for studying the multi-scale statistical approach for CO 2 accounting and risk analysis. A set of geostatistical-based MC simulations of CO 2-oil/gas-water flow and transport in the Morrow formation are conducted for evaluating the risk metrics. A response-surface-based economic model has been derived to calculate the CO 2-EOR profitability for the FWU site with a current oil price, which suggests that approximately 31% of the 1000 realizations can be profitable. If government carbon-tax credits are available, or the oil price goes up or CO 2 capture and operating expenses reduce, more realizations would be profitable.« less

CO 2 Sequestration and Enhanced Oil Recovery at Depleted Oil/Gas Reservoirs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dai, Zhenxue; Viswanathan, Hari; Xiao, Ting

This study presents a quantitative evaluation of the operational and technical risks of an active CO 2-EOR project. A set of risk factor metrics is defined to post-process the Monte Carlo (MC) simulations for statistical analysis. The risk factors are expressed as measurable quantities that can be used to gain insight into project risk (e.g. environmental and economic risks) without the need to generate a rigorous consequence structure, which include (a) CO 2 injection rate, (b) net CO 2 injection rate, (c) cumulative CO 2 storage, (d) cumulative water injection, (e) oil production rate, (f) cumulative oil production, (g) cumulativemore » CH 4 production, and (h) CO 2 breakthrough time. The Morrow reservoir at the Farnsworth Unit (FWU) site, Texas, is used as an example for studying the multi-scale statistical approach for CO 2 accounting and risk analysis. A set of geostatistical-based MC simulations of CO 2-oil/gas-water flow and transport in the Morrow formation are conducted for evaluating the risk metrics. A response-surface-based economic model has been derived to calculate the CO 2-EOR profitability for the FWU site with a current oil price, which suggests that approximately 31% of the 1000 realizations can be profitable. If government carbon-tax credits are available, or the oil price goes up or CO 2 capture and operating expenses reduce, more realizations would be profitable.« less

Using Automatic Speech Recognition Technology with Elicited Oral Response Testing

ERIC Educational Resources Information Center

Cox, Troy L.; Davies, Randall S.

2012-01-01

This study examined the use of automatic speech recognition (ASR) scored elicited oral response (EOR) tests to assess the speaking ability of English language learners. It also examined the relationship between ASR-scored EOR and other language proficiency measures and the ability of the ASR to rate speakers without bias to gender or native…

Role of Intra-operative MRI (iMRI) in Improving Extent of Resection and Survival in Patients with Glioblastoma Multiforme.

PubMed

Khan, Inamullah; Waqas, Muhammad; Shamim, Muhammad Shahzad

2017-07-01

Multiple intraoperative aids have been introduced to improve the extent of resection (EOR) in Glioblastoma Multiforme (GBM) patients, avoiding any new neurological deficits. Intraoperative MRI (iMRI) has been debated for its utility and cost for nearly two decades in neurosurgical literature. Review of literature suggests improved EOR in GBM patients who underwent iMRI assisted surgical resections leading to higher overall survival (OS) and progression free survival (PFS). iMRI provides real time intraoperative imaging with reasonable quality. Higher risk for new postoperative deficits with increased EOR is not reported in any study using iMRI. The level of evidence regarding prognostic benefits of iMRI is still of low quality..

Applying monitoring, verification, and accounting techniques to a real-world, enhanced oil recovery operational CO2 leak

USGS Publications Warehouse

Wimmer, B.T.; Krapac, I.G.; Locke, R.; Iranmanesh, A.

2011-01-01

The use of carbon dioxide (CO2) for enhanced oil recovery (EOR) is being tested for oil fields in the Illinois Basin, USA. While this technology has shown promise for improving oil production, it has raised some issues about the safety of CO2 injection and storage. The Midwest Geological Sequestration Consortium (MGSC) organized a Monitoring, Verification, and Accounting (MVA) team to develop and deploy monitoring programs at three EOR sites in Illinois, Indiana, and Kentucky, USA. MVA goals include establishing baseline conditions to evaluate potential impacts from CO2 injection, demonstrating that project activities are protective of human health and the environment, and providing an accurate accounting of stored CO2. This paper focuses on the use of MVA techniques in monitoring a small CO2 leak from a supply line at an EOR facility under real-world conditions. The ability of shallow monitoring techniques to detect and quantify a CO2 leak under real-world conditions has been largely unproven. In July of 2009, a leak in the pipe supplying pressurized CO2 to an injection well was observed at an MGSC EOR site located in west-central Kentucky. Carbon dioxide was escaping from the supply pipe located approximately 1 m underground. The leak was discovered visually by site personnel and injection was halted immediately. At its largest extent, the hole created by the leak was approximately 1.9 m long by 1.7 m wide and 0.7 m deep in the land surface. This circumstance provided an excellent opportunity to evaluate the performance of several monitoring techniques including soil CO2 flux measurements, portable infrared gas analysis, thermal infrared imagery, and aerial hyperspectral imagery. Valuable experience was gained during this effort. Lessons learned included determining 1) hyperspectral imagery was not effective in detecting this relatively small, short-term CO2 leak, 2) even though injection was halted, the leak remained dynamic and presented a safety risk concern during monitoring activities and, 3) the atmospheric and soil monitoring techniques used were relatively cost-effective, easily and rapidly deployable, and required minimal manpower to set up and maintain for short-term assessments. However, characterization of CO2 distribution near the land surface resulting from a dynamic leak with widely variable concentrations and fluxes was challenging. ?? 2011 Published by Elsevier Ltd.

A Model of Carbon Capture and Storage with Demonstration of Global Warming Potential and Fossil Fuel Resource Use Efficiency

NASA Astrophysics Data System (ADS)

Suebsiri, Jitsopa

Increasing greenhouse gas concentration in the atmosphere influences global climate change even though the level of impact is still unclear. Carbon dioxide capture and storage (CCS) is increasingly seen as an important component of broadly based greenhouse gas reduction measures. Although the other greenhouse gases are more potent, the sheer volume of CO 2 makes it dominant in term of its effect in the atmosphere. To understand the implications, CCS activities should be studied from a full life cycle perspective. This thesis outlines the successful achievement of the objectives of this study in conducting life cycle assessment (LCA), reviewing the carbon dioxide implications only, combining two energy systems, coal-fired electrical generations and CO2 used for enhanced oil recovery (EOR). LCA is the primary approach used in this study to create a tool for CCS environmental evaluation. The Boundary Dam Power Station (BDPS) and the Weyburn-Midale CO 2 EOR Project in Saskatchewan, Canada, are studied and adopted as case scenarios to find the potential for effective application of CCS in both energy systems. This study demonstrates two levels of retrofitting of the BDPS, retrofit of unit 3 or retrofit of all units, combined with three options for CO 2 geological storage: deep saline aquifer, CO2 EOR, and a combination of deep saline aquifer storage and CO2 EOR. Energy output is considered the product of combining these two energy resources (coal and oil). Gigajoules (GJ) are used as the fundamental unit of measurement in comparing the combined energy types. The application of this tool effectively demonstrates the results of application of a CCS system concerning global warming potential (GWP) and fossil fuel resource use efficiency. Other environmental impacts could be analyzed with this tool as well. In addition, the results demonstrate that the GWP reduction is directly related to resource use efficiency. This means the lower the GWP of CCS, the lower resource use efficiency as well. Three processes, coal mining, power production including CO2 capture unit operation, and crude oil usage, must be included when the GWP of CCS is calculated. Moreover, the results from the sensitivity analysis of power generation efficiency present not only a significant reduction of GWP, but also a competitive solution for improving or at least preventing the decrease of fossil fuel resource use efficiency when CCS is applied.

W.A. Parish Post-Combustion CO{sub 2} Capture and Sequestration Project Phase 1 Definition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Armpriester, Anthony; Smith, Roger; Scheriffius, Jeff

2014-02-01

For a secure and sustainable energy future, the United States (U.S.) must reduce its dependence on imported oil and reduce its emissions of carbon dioxide (CO{sub 2}) and other greenhouse gases (GHGs). To meet these strategic challenges, the U.S. wiU have to create fundamentally new technologies with performance levels far beyond what is now possible. Developing advanced post-combustion clean coal technologies for capturing CO{sub 2} from existing coal-fired power plants can play a major role in the country's transition to a sustainable energy future, especially when coupled with CO{sub 2}-enhanced oil recovery (CO{sub 2}-EOR). Pursuant to these goals, NRG Energy,more » Inc. (NRG) submitted an application and entered into a cost-shared collaboration with the U.S. Department of Energy (DOE) under Round 3 of the Clean Coal Power Initiative (CCPI) to advance low-emission coal technologies. The objective of the NRG W A Parish Post-Combustion CO{sub 2} Capture and Sequestration Demonstration Project is to establish the technical feasibility and economic viability of post-combustion CO{sub 2} capture using flue gas from an existing pulverized coal-fired boiler integrated with geologic sequestration via an enhanced oil recovery (EOR) process. To achieve these objectives, the project will be executed in three phases. Each phase represents a distinct aspect of the project execution. The project phases are: • Phase I. Project Definition/Front-End Engineering Design (FEED) • Phase ll. Detailed Engineering, Procurement & Construction • Phase III. Demonstration and Monitoring The purpose of Phase I is to develop the project in sufficient detail to facilitate the decision-making process in progressing to the next stage of project delivery. Phase n. This report provides a complete summary of the FEED study effort, including pertinent project background information, the scope of facilities covered, decisions, challenges, and considerations made regarding configuration and performance of the facility, along with the conceptual design and estimate results. The findings of this report should be considered conceptual in nature and are conditioned on the statements contained herein. The cost of preparing this report (including the FEED study described herein) was funded in part by a $167-million grant provided by the U.S. DOE.« less

Effect of PEO molecular weight on the miscibility and dynamics in epoxy/PEO blends.

PubMed

Lu, Shoudong; Zhang, Rongchun; Wang, Xiaoliang; Sun, Pingchuan; Lv, Weifeng; Liu, Qingjie; Jia, Ninghong

2015-11-01

In this work, the effect of poly(ethylene oxide) (PEO) molecular weight in blends of epoxy (ER) and PEO on the miscibility, inter-chain weak interactions and local dynamics were systematically investigated by multi-frequency temperature modulation DSC and solid-state NMR techniques. We found that the molecular weight (M(w)) of PEO was a crucial factor in controlling the miscibility, chain dynamics and hydrogen bonding interactions between PEO and ER. A critical PEO molecular weight (M(crit)) around 4.5k was found. PEO was well miscible with ER when the molecular weight was below M(crit), where the chain motion of PEO was restricted due to strong inter-chain hydrogen bonding interactions. However, for the blends with high molecular weight PEO (M(w) > M(crit)), the miscibility between PEO and ER was poor, and most of PEO chains were considerably mobile. Finally, polarization inversion spin exchange at magic angle (PISEMA) solid-state NMR experiment further revealed the different mobility of the PEO in ER/PEO blends with different molecular weight of PEO at molecular level. Based on the DSC and NMR results, a tentative model was proposed to illustrate the miscibility in ER/PEO blends.

Appendix for the Final Technical Report - DE FE0009284

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duguid, Andrew

2017-05-29

Carbon capture utilization storage (CCUS) is a potential technology to store anthropogenic emissions for CO 2. Utilization often refers to CO 2-enhanced oil recovery (CO 2-EOR). An important factor in the success of CO 2 storage in saline formations or CO 2-EOR reservoirs is ensuring that the storage occurs safely and is long-term. Assessment of well integrity has become more important for CCS and CO 2-EOR as it has become apparent that wells represent the most likely migration pathway for CO 2 to leave a CCS storage unit or a CO 2-EOR reservoir. Although wells represent a migration pathway theymore » are also the best vehicle for employing technology monitoring CO 2 injection and storage. This contradiction of being a potential migration path and key monitoring technology leads to a need to understand how monitoring wells may be similar or different in comparison to other types of wells with respect to migration risk. The maturation and completion US Department of Energy sponsored research projects presents an opportunity to assess the integrity of monitoring wells that have been exposed to injected CO 2. This paper discusses an integrity assessment of two monitoring wells in an operating CO 2-EOR flood in Mississippi, USA. The CFU31F-2 and CFU31F-3 monitoring wells were constructed to test monitoring technologies in and above a commercial CO 2-EOR project. The materials selected and the design of the well were optimized for monitoring. Carbonation in CFU31-F2 was seen as high as 7900 ft, above what was considered top of cement based on the logs. Time-lapse comparison of cement bond amplitude data and acoustic impedance maps show a deterioration of signal that implies a deterioration of cement bond or cement along much of the cemented annulus in the long-string section. Analysis of sidewall cores using XRD and LA-ICP-MS validated the log interpretation by confirming the degradation of cement (carbonation) along the casing-cement interface. The ultrasonic image maps also clearly identify the control lines and monitoring technology attached to the outside of the of the long-string casing on each well studied. The control lines appear as microdebonded or fluid filled vertical features implying that they could act as leakage pathways. The sidewall core through the control line at 10380 ft confirms that CO 2 is migrating along the control line with heavily carbonated cement at the control line interface. LA-ICP-MS and XRD on formation interface of the sidewall cores collected in both wells indicates that CO 2 is also moving of the cement-formation interface. LA-ICP-MS and XRD indicate that the amount carbonation in the center of the cores was less than the carbonation at the interfaces. Indicating that CO 2 is reaching the center of the cores by diffusing in from the interfaces and not migrating up from the reservoir though the porous matrix of the cement. This agrees with Duguid et al. [5] and Carey et al. [1] who have found that the interfaces in the well are more conductive than the porous network of the cement. Both the materials used to construct the well and the decision to attach monitoring technology to the outside of the well may have contributed to the migration of CO 2 along the interfaces. Careful consideration should be given to material selection to ensure that it does not degrade when in contact with the fluids in the reservoir and overlying strata. The addition of the control line on the outside of the casing complicated the cement placement and likely caused no cement to bond to the casing adjacent to the control line leading out of the reservoir. Further study of other wells with external lines should be conducted to see of the results of the construction of CFU31-F2 and -F3 is normal or an exception.« less

Automatic estimation of extent of resection and residual tumor volume of patients with glioblastoma.

PubMed

Meier, Raphael; Porz, Nicole; Knecht, Urspeter; Loosli, Tina; Schucht, Philippe; Beck, Jürgen; Slotboom, Johannes; Wiest, Roland; Reyes, Mauricio

2017-10-01

OBJECTIVE In the treatment of glioblastoma, residual tumor burden is the only prognostic factor that can be actively influenced by therapy. Therefore, an accurate, reproducible, and objective measurement of residual tumor burden is necessary. This study aimed to evaluate the use of a fully automatic segmentation method-brain tumor image analysis (BraTumIA)-for estimating the extent of resection (EOR) and residual tumor volume (RTV) of contrast-enhancing tumor after surgery. METHODS The imaging data of 19 patients who underwent primary resection of histologically confirmed supratentorial glioblastoma were retrospectively reviewed. Contrast-enhancing tumors apparent on structural preoperative and immediate postoperative MR imaging in this patient cohort were segmented by 4 different raters and the automatic segmentation BraTumIA software. The manual and automatic results were quantitatively compared. RESULTS First, the interrater variabilities in the estimates of EOR and RTV were assessed for all human raters. Interrater agreement in terms of the coefficient of concordance (W) was higher for RTV (W = 0.812; p < 0.001) than for EOR (W = 0.775; p < 0.001). Second, the volumetric estimates of BraTumIA for all 19 patients were compared with the estimates of the human raters, which showed that for both EOR (W = 0.713; p < 0.001) and RTV (W = 0.693; p < 0.001) the estimates of BraTumIA were generally located close to or between the estimates of the human raters. No statistically significant differences were detected between the manual and automatic estimates. BraTumIA showed a tendency to overestimate contrast-enhancing tumors, leading to moderate agreement with expert raters with respect to the literature-based, survival-relevant threshold values for EOR. CONCLUSIONS BraTumIA can generate volumetric estimates of EOR and RTV, in a fully automatic fashion, which are comparable to the estimates of human experts. However, automated analysis showed a tendency to overestimate the volume of a contrast-enhancing tumor, whereas manual analysis is prone to subjectivity, thereby causing considerable interrater variability.

Noble Gas signatures of Enhanced Oil Recovery

NASA Astrophysics Data System (ADS)

Barry, P. H.; Kulongoski, J. T.; Tyne, R. L.; Hillegonds, D.; Byrne, D. J.; Landon, M. K.; Ballentine, C. J.

2017-12-01

Noble gases are powerful tracers of fluids from various oil and gas production activities in hydrocarbon reservoirs and nearby groundwater. Non-radiogenic noble gases are introduced into undisturbed oil and natural gas reservoirs through exchange with formation waters [1-3]. Reservoirs with extensive hydraulic fracturing, injection for enhanced oil recovery (EOR), and/or waste disposal also show evidence for a component of noble gases introduced from air [4]. Isotopic and elemental ratios of noble gases can be used to 1) assess the migration history of the injected and formation fluids, and 2) determine the extent of exchange between multiphase fluids in different reservoirs. We present noble gas isotope and abundance data from casing, separator and injectate gases of the Lost Hills and Fruitvale oil fields in the San Joaquin basin, California. Samples were collected as part of the California State Water Resource Control Board's Oil and Gas Regional Groundwater Monitoring Program. Lost Hills (n=7) and Fruitvale (n=2) gases are geochemically distinct and duplicate samples are highly reproducible. Lost Hills casing gas samples were collected from areas where EOR and hydraulic fracturing has occurred in the past several years, and from areas where EOR is absent. The Fruitvale samples were collected from a re-injection port. All samples are radiogenic in their He isotopes, typical of a crustal environment, and show enrichments in heavy noble gases, resulting from preferential adsorption on sediments. Fruitvale samples reflect air-like surface conditions, with higher air-derived noble gas concentrations. Lost Hills gases show a gradation from pristine crustal signatures - indicative of closed-system exchange with formation fluids - to strongly air-contaminated signatures in the EOR region. Pristine samples can be used to determine the extent of hydrocarbon exchange with fluids, whereas samples with excess air can be used to quantify the extent of EOR. Determining noble gas baseline values for pristine vs. recently modified (EOR, hydraulic fracturing) zones will be critical for interpreting the origin of any fugitive gases identified in nearby aquifers. [1] Ballentine et al., (1996) GCA, 60, 831-849 [2] Barry et al., (2016) GCA, 194, 291-309. [3] Barry et al., (2017) Geology, 45, 9. Darrah et al., (2014) PNAS 111, 39.

The system-wide economics of a carbon dioxide capture, utilization, and storage network: Texas Gulf Coast with pure CO2-EOR flood

NASA Astrophysics Data System (ADS)

King, Carey W.; Gülen, Gürcan; Cohen, Stuart M.; Nuñez-Lopez, Vanessa

2013-09-01

This letter compares several bounding cases for understanding the economic viability of capturing large quantities of anthropogenic CO2 from coal-fired power generators within the Electric Reliability Council of Texas electric grid and using it for pure CO2 enhanced oil recovery (EOR) in the onshore coastal region of Texas along the Gulf of Mexico. All captured CO2 in excess of that needed for EOR is sequestered in saline formations at the same geographic locations as the oil reservoirs but at a different depth. We analyze the extraction of oil from the same set of ten reservoirs within 20- and five-year time frames to describe how the scale of the carbon dioxide capture, utilization, and storage (CCUS) network changes to meet the rate of CO2 demand for oil recovery. Our analysis shows that there is a negative system-wide net present value (NPV) for all modeled scenarios. The system comes close to breakeven economics when capturing CO2 from three coal-fired power plants to produce oil via CO2-EOR over 20 years and assuming no CO2 emissions penalty. The NPV drops when we consider a larger network to produce oil more quickly (21 coal-fired generators with CO2 capture to produce 80% of the oil within five years). Upon applying a CO2 emissions penalty of 602009/tCO2 to fossil fuel emissions to ensure that coal-fired power plants with CO2 capture remain in baseload operation, the system economics drop significantly. We show near profitability for the cash flow of the EOR operations only; however, this situation requires relatively cheap electricity prices during operation.

A Multi-scale Approach for CO2 Accounting and Risk Analysis in CO2 Enhanced Oil Recovery Sites

NASA Astrophysics Data System (ADS)

Dai, Z.; Viswanathan, H. S.; Middleton, R. S.; Pan, F.; Ampomah, W.; Yang, C.; Jia, W.; Lee, S. Y.; McPherson, B. J. O. L.; Grigg, R.; White, M. D.

2015-12-01

Using carbon dioxide in enhanced oil recovery (CO2-EOR) is a promising technology for emissions management because CO2-EOR can dramatically reduce carbon sequestration costs in the absence of greenhouse gas emissions policies that include incentives for carbon capture and storage. This study develops a multi-scale approach to perform CO2 accounting and risk analysis for understanding CO2 storage potential within an EOR environment at the Farnsworth Unit of the Anadarko Basin in northern Texas. A set of geostatistical-based Monte Carlo simulations of CO2-oil-water flow and transport in the Marrow formation are conducted for global sensitivity and statistical analysis of the major risk metrics: CO2 injection rate, CO2 first breakthrough time, CO2 production rate, cumulative net CO2 storage, cumulative oil and CH4 production, and water injection and production rates. A global sensitivity analysis indicates that reservoir permeability, porosity, and thickness are the major intrinsic reservoir parameters that control net CO2 injection/storage and oil/CH4 recovery rates. The well spacing (the distance between the injection and production wells) and the sequence of alternating CO2 and water injection are the major operational parameters for designing an effective five-spot CO2-EOR pattern. The response surface analysis shows that net CO2 injection rate increases with the increasing reservoir thickness, permeability, and porosity. The oil/CH4 production rates are positively correlated to reservoir permeability, porosity and thickness, but negatively correlated to the initial water saturation. The mean and confidence intervals are estimated for quantifying the uncertainty ranges of the risk metrics. The results from this study provide useful insights for understanding the CO2 storage potential and the corresponding risks of commercial-scale CO2-EOR fields.

Deformation of interface in a partially miscible system during favorable displacement

NASA Astrophysics Data System (ADS)

Suzuki, Ryuta; Nagatsu, Yuichiro; Mishra, Manoranjan; Ban, Takahiko

2017-11-01

The Saffman-Taylor instability triggers a well-known viscous fingering (VF, called unfavorable displacement), occurring when a less viscous fluid displaces a more viscous one in porous media or in a Hele-Shaw cell because the boundary of the two fluids becomes hydrodynamically unstable. In the reverse situation (called favorable displacement) in which a more viscous fluid displaces a less viscous one, no instabilities occur due to hydrodynamically stable system. It has been reported that the favorable displacements become unstable by several physicochemical effects. So far, studies of both displacements have focused on fluids that are either fully miscible or immiscible. However, little attention has been paid to displacements in partially miscible system. Here, we have discovered that a partial miscibility triggers fingering instability in a favorable displacement without any chemical reactions. The occurrence of this new instability is induced by not hydrodynamic effects but a thermodynamic effect that is so-called Korteweg effect in which convection is induced during phase separation process in a partially miscible system.

Hydrodynamic instabilities in miscible fluids

NASA Astrophysics Data System (ADS)

Truzzolillo, Domenico; Cipelletti, Luca

2018-01-01

Hydrodynamic instabilities in miscible fluids are ubiquitous, from natural phenomena up to geological scales, to industrial and technological applications, where they represent the only way to control and promote mixing at low Reynolds numbers, well below the transition from laminar to turbulent flow. As for immiscible fluids, the onset of hydrodynamic instabilities in miscible fluids is directly related to the physics of their interfaces. The focus of this review is therefore on the general mechanisms driving the growth of disturbances at the boundary between miscible fluids, under a variety of forcing conditions. In the absence of a regularizing mechanism, these disturbances would grow indefinitely. For immiscible fluids, interfacial tension provides such a regularizing mechanism, because of the energy cost associated to the creation of new interface by a growing disturbance. For miscible fluids, however, the very existence of interfacial stresses that mimic an effective surface tension is debated. Other mechanisms, however, may also be relevant, such as viscous dissipation. We shall review the stabilizing mechanisms that control the most common hydrodynamic instabilities, highlighting those cases for which the lack of an effective interfacial tension poses deep conceptual problems in the mathematical formulation of a linear stability analysis. Finally, we provide a short overview on the ongoing research on the effective, out of equilibrium interfacial tension between miscible fluids.

Characterization of interfaces in Binary and Ternary Polymer Blends by Positron Lifetime Spectroscopy

NASA Astrophysics Data System (ADS)

Ranganathaiah, C.

2015-06-01

A miscible blend is a single-phase system with compact packing of the polymeric chains/segments due configuration/conformational changes upon blending. Differential Scanning Calorimetry (DSC) is the most employed method to ascertain whether the blend is miscible or immiscible. Positron Lifetime Spectroscopy (PLS) has been employed in recent times to study miscibility properties of polymer blends by monitoring the ortho-Positronium annihilation lifetimes as function of composition. However, just free volume monitoring and the DSC methods fail to provide the composition dependent miscibility of blends. To overcome this limitation, an alternative approach based on hydrodynamic interactions has been developed to derive this information using the same o-Ps lifetime measurements. This has led to the development of a new method of measuring composition dependent miscibility level in binary and ternary polymer blends. Further, the new method also provides interface characteristics for immiscible blends. The interactions between the blend components has a direct bearing on the strength of adhesion at the interface and hence the hydrodynamic interaction. Understanding the characteristic of interfaces which decides the miscibility level of the blend and their end applications is made easy by the present method. The efficacy of the present method is demonstrated for few binary and ternary blends.

21SSD: a new public 21-cm EoR database

NASA Astrophysics Data System (ADS)

Eames, Evan; Semelin, Benoît

2018-05-01

With current efforts inching closer to detecting the 21-cm signal from the Epoch of Reionization (EoR), proper preparation will require publicly available simulated models of the various forms the signal could take. In this work we present a database of such models, available at 21ssd.obspm.fr. The models are created with a fully-coupled radiative hydrodynamic simulation (LICORICE), and are created at high resolution (10243). We also begin to analyse and explore the possible 21-cm EoR signals (with Power Spectra and Pixel Distribution Functions), and study the effects of thermal noise on our ability to recover the signal out to high redshifts. Finally, we begin to explore the concepts of `distance' between different models, which represents a crucial step towards optimising parameter space sampling, training neural networks, and finally extracting parameter values from observations.

Foreground Characterization for the Murchison Widefield Array Using the Jansky Very Large Array

NASA Astrophysics Data System (ADS)

Busch, Michael P.; Bowman, Judd D.; Kittiwisit, Piyanat; Jacobs, Danny

2016-01-01

One of the most compelling questions in astrophysics today is how the process of galaxy formation unfolded during the Epoch of Reionization (EoR). A new generation of radio telescopes, including the Murchison Widefield Array (MWA) and others, are attempting to capture the redshifted 21cm signal from neutral hydrogen during the EoR. Mapping the reionization of the intergalactic medium (IGM) is one of the core objectives of 21 cm observatories. A pressing concern of these observations is the bright foreground sources in the telescope's sidelobes outside the primary beam of the MWA. These sources, including AGN, radio galaxies and local Galactic sources, are numerous and difficult to deal with. These foreground contaminants are five orders of magnitude brighter than the redshifted 21 cm emission expected from the IGM during the EoR. The Jansky Very Large Array (JVLA) in New Mexico can provide sensitive characterization of these sources in the MWA's northern sidelobe. We observed 100 bright radio sources using the JVLA in P-band and characterized these sources by extracting the spectral fits and fluxes for each source. By creating a foreground model for these data, the MWA will be able to better subtract these sources from future EoR measurements. We report the current status of the creation of the foreground model.

Initial experience of using high field strength intraoperative MRI for neurosurgical procedures.

PubMed

Raheja, Amol; Tandon, Vivek; Suri, Ashish; Sarat Chandra, P; Kale, Shashank S; Garg, Ajay; Pandey, Ravindra M; Kalaivani, Mani; Mahapatra, Ashok K; Sharma, Bhawani S

2015-08-01

We report our initial experience to optimize neurosurgical procedures using high field strength intraoperative magnetic resonance imaging (IOMRI) in 300 consecutive patients as high field strength IOMRI rapidly becomes the standard of care for neurosurgical procedures. Three sequential groups (groups A, B, C; n=100 each) were compared with respect to time management, complications and technical difficulties to assess improvement in these parameters with experience. We observed a reduction in the number of technical difficulties (p<0.001), time to induction (p<0.001) and total anesthesia time (p=0.007) in sequential groups. IOMRI was performed for neuronavigation guidance (n=252) and intraoperative validation of extent of resection (EOR; n=67). Performing IOMRI increased the EOR over and beyond the primary surgical attempt in 20.5% (29/141) and 18% (11/61) of patients undergoing glioma and pituitary surgery, respectively. Overall, EOR improved in 59.7% of patients undergoing IOMRI (40/67). Intraoperative tractography and real time navigation using re-uploaded IOMRI images (accounting for brain shift) helps in intraoperative planning to reduce complications. IOMRI is an asset to neurosurgeons, helping to augment the EOR, especially in glioma and pituitary surgery, with no significant increase in morbidity to the patient. Copyright © 2015 Elsevier Ltd. All rights reserved.

Modeling the Radio Foreground for Detection of CMB Spectral Distortions from the Cosmic Dawn and the Epoch of Reionization

NASA Astrophysics Data System (ADS)

Sathyanarayana Rao, Mayuri; Subrahmanyan, Ravi; Udaya Shankar, N.; Chluba, Jens

2017-05-01

Cosmic baryon evolution during the Cosmic Dawn and Reionization results in redshifted 21-cm spectral distortions in the cosmic microwave background (CMB). These encode information about the nature and timing of first sources over redshifts 30-6 and appear at meter wavelengths as a tiny CMB distortion along with the Galactic and extragalactic radio sky, which is orders of magnitude brighter. Therefore, detection requires precise methods to model foregrounds. We present a method of foreground fitting using maximally smooth (MS) functions. We demonstrate the usefulness of MS functions over traditionally used polynomials to separate foregrounds from the Epoch of Reionization (EoR) signal. We also examine the level of spectral complexity in plausible foregrounds using GMOSS, a physically motivated model of the radio sky, and find that they are indeed smooth and can be modeled by MS functions to levels sufficient to discern the vanilla model of the EoR signal. We show that MS functions are loss resistant and robustly preserve EoR signal strength and turning points in the residuals. Finally, we demonstrate that in using a well-calibrated spectral radiometer and modeling foregrounds with MS functions, the global EoR signal can be detected with a Bayesian approach with 90% confidence in 10 minutes’ integration.

Evaluating the climate benefits of CO2-enhanced oil recovery using life cycle analysis.

PubMed

Cooney, Gregory; Littlefield, James; Marriott, Joe; Skone, Timothy J

2015-06-16

This study uses life cycle analysis (LCA) to evaluate the greenhouse gas (GHG) performance of carbon dioxide (CO2) enhanced oil recovery (EOR) systems. A detailed gate-to-gate LCA model of EOR was developed and incorporated into a cradle-to-grave boundary with a functional unit of 1 MJ of combusted gasoline. The cradle-to-grave model includes two sources of CO2: natural domes and anthropogenic (fossil power equipped with carbon capture). A critical parameter is the crude recovery ratio, which describes how much crude is recovered for a fixed amount of purchased CO2. When CO2 is sourced from a natural dome, increasing the crude recovery ratio decreases emissions, the opposite is true for anthropogenic CO2. When the CO2 is sourced from a power plant, the electricity coproduct is assumed to displace existing power. With anthropogenic CO2, increasing the crude recovery ratio reduces the amount of CO2 required, thereby reducing the amount of power displaced and the corresponding credit. Only the anthropogenic EOR cases result in emissions lower than conventionally produced crude. This is not specific to EOR, rather the fact that carbon-intensive electricity is being displaced with captured electricity, and the fuel produced from that system receives a credit for this displacement.

Comprehensive, Quantitative Risk Assessment of CO{sub 2} Geologic Sequestration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lepinski, James

2013-09-30

A Quantitative Failure Modes and Effects Analysis (QFMEA) was developed to conduct comprehensive, quantitative risk assessments on CO{sub 2} capture, transportation, and sequestration or use in deep saline aquifers, enhanced oil recovery operations, or enhanced coal bed methane operations. The model identifies and characterizes potential risks; identifies the likely failure modes, causes, effects and methods of detection; lists possible risk prevention and risk mitigation steps; estimates potential damage recovery costs, mitigation costs and costs savings resulting from mitigation; and ranks (prioritizes) risks according to the probability of failure, the severity of failure, the difficulty of early failure detection and themore » potential for fatalities. The QFMEA model generates the necessary information needed for effective project risk management. Diverse project information can be integrated into a concise, common format that allows comprehensive, quantitative analysis, by a cross-functional team of experts, to determine: What can possibly go wrong? How much will damage recovery cost? How can it be prevented or mitigated? What is the cost savings or benefit of prevention or mitigation? Which risks should be given highest priority for resolution? The QFMEA model can be tailored to specific projects and is applicable to new projects as well as mature projects. The model can be revised and updated as new information comes available. It accepts input from multiple sources, such as literature searches, site characterization, field data, computer simulations, analogues, process influence diagrams, probability density functions, financial analysis models, cost factors, and heuristic best practices manuals, and converts the information into a standardized format in an Excel spreadsheet. Process influence diagrams, geologic models, financial models, cost factors and an insurance schedule were developed to support the QFMEA model. Comprehensive, quantitative risk assessments were conducted on three (3) sites using the QFMEA model: (1) SACROC Northern Platform CO{sub 2}-EOR Site in the Permian Basin, Scurry County, TX, (2) Pump Canyon CO{sub 2}-ECBM Site in the San Juan Basin, San Juan County, NM, and (3) Farnsworth Unit CO{sub 2}-EOR Site in the Anadarko Basin, Ochiltree County, TX. The sites were sufficiently different from each other to test the robustness of the QFMEA model.« less

A database and probabilistic assessment methodology for carbon dioxide enhanced oil recovery and associated carbon dioxide retention in the United States

USGS Publications Warehouse

Warwick, Peter D.; Verma, Mahendra K.; Attanasi, Emil; Olea, Ricardo A.; Blondes, Madalyn S.; Freeman, Philip; Brennan, Sean T.; Merrill, Matthew; Jahediesfanjani, Hossein; Roueche, Jacqueline; Lohr, Celeste D.

2017-01-01

The U.S. Geological Survey (USGS) has developed an assessment methodology for estimating the potential incremental technically recoverable oil resources resulting from carbon dioxide-enhanced oil recovery (CO2-EOR) in reservoirs with appropriate depth, pressure, and oil composition. The methodology also includes a procedure for estimating the CO2 that remains in the reservoir after the CO2-EOR process is complete. The methodology relies on a reservoir-level database that incorporates commercially available geologic and engineering data. The mathematical calculations of this assessment methodology were tested and produced realistic results for the Permian Basin Horseshoe Atoll, Upper Pennsylvanian-Wolfcampian Play (Texas, USA). The USGS plans to use the new methodology to conduct an assessment of technically recoverable hydrocarbons and associated CO2 sequestration resulting from CO2-EOR in the United States.

EoR imaging with the SKA: the challenge of foreground removal

NASA Astrophysics Data System (ADS)

Bonaldi, Anna

2018-05-01

21-cm observations of the Cosmic dawn (CD) and Epoch of Reionization (EoR) are one of the high priority science objectives for SKA Low. One of the most difficult aspects of the 21-cm measurement is the presence of foreground emission, due to our Galaxy and extragalactic sources, which is about four orders of magnitude brighter than the cosmological signal. While end-to-end simulations are being produced to investigate in details the foreground subtraction strategy, it is useful to complement this thorough but time-consuming approach with simpler, quicker ways to evaluate performance and identify possible critical steps. In this work, I present a forecast method, based on Bonaldi et al. (2015), Bonaldi & Ricciardi (2011), to understand the level of residual contamination after a component separation step, and its impact on our ability to investigate CD and EoR.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moore, David F.; Aguirre, James E.; Parsons, Aaron R.

Experiments aimed at detecting highly-redshifted 21 cm emission from the epoch of reionization (EoR) are plagued by the contamination of foreground emission. A potentially important source of contaminating foregrounds may be Faraday-rotated, polarized emission, which leaks into the estimate of the intrinsically unpolarized EoR signal. While these foregrounds' intrinsic polarization may not be problematic, the spectral structure introduced by the Faraday rotation could be. To better understand and characterize these effects, we present a simulation of the polarized sky between 120 and 180 MHz. We compute a single visibility, and estimate the three-dimensional power spectrum from that visibility using themore » delay spectrum approach presented in Parsons et al. Using the Donald C. Backer Precision Array to Probe the Epoch of Reionization as an example instrument, we show the expected leakage into the unpolarized power spectrum to be several orders of magnitude above the expected 21 cm EoR signal.« less

Influence of miscibility phenomenon on crystalline polymorph transition in poly(vinylidene fluoride)/acrylic rubber/clay nanocomposite hybrid.

PubMed

Abolhasani, Mohammad Mahdi; Naebe, Minoo; Jalali-Arani, Azam; Guo, Qipeng

2014-01-01

In this paper, intercalation of nanoclay in the miscible polymer blend of poly(vinylidene fluoride) (PVDF) and acrylic rubber(ACM) was studied. X-ray diffraction was used to investigate the formation of nanoscale polymer blend/clay hybrid. Infrared spectroscopy and X-ray analysis revealed the coexistence of β and γ crystalline forms in PVDF/Clay nanocomposite while α crystalline form was found to be dominant in PVDF/ACM/Clay miscible hybrids. Flory-Huggins interaction parameter (B) was used to further explain the miscibility phenomenon observed. The B parameter was determined by combining the melting point depression and the binary interaction model. The estimated B values for the ternary PVDF/ACM/Clay and PVDF/ACM pairs were all negative, showing both proper intercalation of the polymer melt into the nanoclay galleries and the good miscibility of PVDF and ACM blend. The B value for the PVDF/ACM blend was almost the same as that measured for the PVDF/ACM/Clay hybrid, suggesting that PVDF chains in nanocomposite hybrids interact with ACM chains and that nanoclay in hybrid systems is wrapped by ACM molecules.

Miscibility, Crystallization, and Rheological Behavior of Solution Casting Poly(3-hydroxybutyrate)/poly(ethylene succinate) Blends Probed by Differential Scanning Calorimetry, Rheology, and Optical Microscope Techniques

NASA Astrophysics Data System (ADS)

Sun, Wei-hua; Qiao, Xiao-ping; Cao, Qi-kun; Liu, Jie-ping

2010-02-01

The miscibility and crystallization of solution casting biodegradable poly(3-hydroxybutyrate)/poly(ethylene succinate) (PHB/PES) blends was investigated by differential scanning calorimetry, rheology, and optical microscopy. The blends showed two glass transition temperatures and a depression of melting temperature of PHB with compositions in phase diagram, which indicated that the blend was partially miscible. The morphology observation supported this result. It was found that the PHB and PES can crystallize simultaneously or upon stepwise depending on the crystallization temperatures and compositions. The spherulite growth rate of PHB increased with increasing of PES content. The influence of compositions on the spherulitic growth rate for the partially miscible polymer blends was discussed.

Impact of removed tumor volume and location on patient outcome in glioblastoma.

PubMed

Awad, Al-Wala; Karsy, Michael; Sanai, Nader; Spetzler, Robert; Zhang, Yue; Xu, Yizhe; Mahan, Mark A

2017-10-01

Glioblastoma is an aggressive primary brain tumor with devastatingly poor prognosis. Multiple studies have shown the benefit of wider extent of resection (EOR) on patient overall survival (OS) and worsened survival with larger preoperative tumor volumes. However, the concomitant impact of postoperative tumor volume and eloquent location on OS has yet to be fully evaluated. We performed a retrospective chart review of adult patients treated for glioblastoma from January 2006 through December 2011. Adherence to standardized postoperative chemoradiation protocols was used as an inclusion criterion. Detailed volumetric and location analysis was performed on immediate preoperative and immediate postoperative magnetic resonance imaging. Cox proportional hazard modeling approach was employed to explore the modifying effects of EOR and eloquent location after adjusting for various confounders and associated characteristics, such as preoperative tumor volume and demographics. Of the 471 screened patients, 141 were excluded because they did not meet all inclusion criteria. The mean (±SD) age of the remaining 330 patients (60.6% male) was 58.9 ± 12.9 years; the mean preoperative and postoperative Karnofsky performance scores (KPSs) were 76.2 ± 10.3 and 80.0 ± 16.6, respectively. Preoperative tumor volume averaged 33.2 ± 29.0 ml, postoperative residual was 4.0 ± 8.1 ml, and average EOR was 88.6 ± 17.6%. The observed average follow-up was 17.6 ± 15.7 months, and mean OS was 16.7 ± 14.4 months. Survival analysis showed significantly shorter survival for patients with lesions in periventricular (16.8 ± 1.7 vs. 21.5 ± 1.4 mo, p = 0.03), deep nuclei/basal ganglia (11.6 ± 1.7 vs. 20.6 ± 1.2, p = 0.002), and multifocal (12.0 ± 1.4 vs. 21.3 ± 1.3 months, p = 0.0001) locations, but no significant influence on survival was seen for eloquent cortex sites (p = 0.14, range 0.07-0.9 for all individual locations). OS significantly improved with EOR in univariate analysis, averaging 22.3, 19.7, and 13.2 months for >90, 80-90, and 70-80% resection, respectively. Survival was 22.8, 19.0, and 12.7 months for 0, 0-5, and 5-10 ml postoperative residual, respectively. A hazard model showed that larger preoperative tumor volume [hazard ratio (HR) 1.05, 95% CI 1.02-1.07], greater age (HR 1.02, 95% CI 1.01-1.03), multifocality (HR 1.44, 95% CI 1.01-2.04), and deep nuclei/basal ganglia (HR 2.05, CI 1.27-3.3) were the most predictive of poor survival after adjusting for KPS and tumor location. There was a negligible but significant interaction between EOR and preoperative tumor volume (HR 0.9995, 95% CI 0.9993-0.9998), but EOR alone did not correlate with OS after adjusting for other factors. The interaction between EOR and preoperative tumor volume represented tumor volume removed during surgery. In conclusion, EOR alone was not an important predictor of outcome during GBM treatment once preoperative tumor volume, age, and deep nuclei/basal ganglia location were factored. Instead, the interaction between EOR and preoperative volume, representing reduced disease burden, was an important predictor of reducing OS. Removal of tumor from eloquent cortex did not impact postoperative KPS. These results suggest aggressive surgical treatment to reduce postoperative residual while maintaining postoperative KPS may aid patient survival outcomes for a given tumor size and location.

Carbon Capture and Sequestration (CCS)

DTIC Science & Technology

2009-06-19

tons of CO2 underground each year to help recover oil and gas resources (enhanced oil recovery , or EOR).1 Also, potentially large amounts of CO2 ... CO2 will be used for enhanced gas recovery at a nearby natural gas field. See http://www.vattenfall.com/www/co2_en/ co2_en/Gemeinsame_Inhalte...for enhanced oil recovery (EOR).18 Transporting CO2 in pipelines is similar to transporting petroleum products like natural gas and oil; it requires

Modeling the Radio Foreground for Detection of CMB Spectral Distortions from the Cosmic Dawn and the Epoch of Reionization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sathyanarayana Rao, Mayuri; Subrahmanyan, Ravi; Shankar, N Udaya

Cosmic baryon evolution during the Cosmic Dawn and Reionization results in redshifted 21-cm spectral distortions in the cosmic microwave background (CMB). These encode information about the nature and timing of first sources over redshifts 30–6 and appear at meter wavelengths as a tiny CMB distortion along with the Galactic and extragalactic radio sky, which is orders of magnitude brighter. Therefore, detection requires precise methods to model foregrounds. We present a method of foreground fitting using maximally smooth (MS) functions. We demonstrate the usefulness of MS functions over traditionally used polynomials to separate foregrounds from the Epoch of Reionization (EoR) signal.more » We also examine the level of spectral complexity in plausible foregrounds using GMOSS, a physically motivated model of the radio sky, and find that they are indeed smooth and can be modeled by MS functions to levels sufficient to discern the vanilla model of the EoR signal. We show that MS functions are loss resistant and robustly preserve EoR signal strength and turning points in the residuals. Finally, we demonstrate that in using a well-calibrated spectral radiometer and modeling foregrounds with MS functions, the global EoR signal can be detected with a Bayesian approach with 90% confidence in 10 minutes’ integration.« less

Ultrathin layered double hydroxide nanosheets with Ni(III) active species obtained by exfoliation for highly efficient ethanol electrooxidation.

PubMed

Xu, Liang; Wang, Zhe; Chen, Xu; Qu, Zongkai; Li, Feng; Yang, Wensheng

2018-01-10

The development of non-precious metal electrocatalysts for renewable energy conversion and storage is compelling but greatly challenging due to low activity of the existing catalysts. Herein, the ultrathin NiAl-layered double hydroxide nanosheets (NiAl-LDH-NSs) are prepared by simple liquid-exfoliation of bulk NiAl-LDHs and first used as ethanol electrooxidation catalysts. The ultrathin two-dimensional (2D) structure ensures that the LDH nanosheets expose a greater number of active sites. More importantly, much Ni(III) active species (NiOOH) in the ultrathin nanosheets are formed by the exfoliation process, which play an authentic catalytic role in the ethanol oxidation reaction (EOR). The presence of NiOOH remarkably improves the reactivity and electrical conductivity of LDH nanosheets. These synergistic effects lead to strikingly more than 30 times enhanced EOR activity of NiAl-LDH-NSs compared to bulk NiAl-LDHs. The obtained electrocatalytic activity is also much better than those of most Ni- and LDH-based EOR catalysts reported to date. In addition, the ultrathin NiAl-LDH-NS electrocatalyst also exhibits good long-term stability (maintain 81.8% of the original value after 10000 s). This study not only provides a highly competitive EOR catalyst, but also opens new avenues toward the design of highly efficient electrode materials that have various potential applications in supercapacitor, Ni-MH battery and other electrocatalytic systems.

An Epoch of Reionization simulation pipeline based on BEARS

NASA Astrophysics Data System (ADS)

Krause, Fabian; Thomas, Rajat M.; Zaroubi, Saleem; Abdalla, Filipe B.

2018-10-01

The quest to unlock the mysteries of the Epoch of Reionization (EoR) is well poised with many experiments at diverse wavelengths beginning to gather data. Albeit these efforts, we are yet uncertain about the various factors that influence the EoR which include, the nature of the sources, their spectral characteristics (blackbody temperatures, power-law indices), clustering property, efficiency, duty cycle etc. Given these physical uncertainties that define the EoR, we need fast and efficient computational methods to model and analyze the data in order to provide confidence bounds on the parameters that influence the brightness temperature at 21-cm. Towards this goal we developed a pipeline that combines dark matter-only N-body simulations with exact 1-dimensional radiative transfer computations to approximate exact 3-dimensional radiative transfer. Because these simulations are about two to three orders of magnitude faster than the exact 3-dimensional methods, they can be used to explore the parameter space of the EoR systematically. A fast scheme like this pipeline could be incorporated into a Bayesian framework for parameter estimation. In this paper we detail the construction of the pipeline and describe how to use the software which is being made publicly available. We show the results of running the pipeline for four test cases of sources with various spectral energy distributions and compare their outputs using various statistics.

CO2 Accounting and Risk Analysis for CO2 Sequestration at Enhanced Oil Recovery Sites.

PubMed

Dai, Zhenxue; Viswanathan, Hari; Middleton, Richard; Pan, Feng; Ampomah, William; Yang, Changbing; Jia, Wei; Xiao, Ting; Lee, Si-Yong; McPherson, Brian; Balch, Robert; Grigg, Reid; White, Mark

2016-07-19

Using CO2 in enhanced oil recovery (CO2-EOR) is a promising technology for emissions management because CO2-EOR can dramatically reduce sequestration costs in the absence of emissions policies that include incentives for carbon capture and storage. This study develops a multiscale statistical framework to perform CO2 accounting and risk analysis in an EOR environment at the Farnsworth Unit (FWU), Texas. A set of geostatistical-based Monte Carlo simulations of CO2-oil/gas-water flow and transport in the Morrow formation are conducted for global sensitivity and statistical analysis of the major risk metrics: CO2/water injection/production rates, cumulative net CO2 storage, cumulative oil/gas productions, and CO2 breakthrough time. The median and confidence intervals are estimated for quantifying uncertainty ranges of the risk metrics. A response-surface-based economic model has been derived to calculate the CO2-EOR profitability for the FWU site with a current oil price, which suggests that approximately 31% of the 1000 realizations can be profitable. If government carbon-tax credits are available, or the oil price goes up or CO2 capture and operating expenses reduce, more realizations would be profitable. The results from this study provide valuable insights for understanding CO2 storage potential and the corresponding environmental and economic risks of commercial-scale CO2-sequestration in depleted reservoirs.

Next Generation Surfactants for Improved Chemical Flooding Technology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Laura Wesson; Prapas Lohateeraparp; Jeffrey Harwell

2012-05-31

The principle objective of this project was to characterize and test current and next generation high performance surfactants for improved chemical flooding technology, focused on reservoirs in the Pennsylvanian-aged (Penn) sands. In order to meet this objective the characteristic curvatures (Cc) of twenty-eight anionic surfactants selected for evaluation for use in chemical flooding formulations were determined. The Cc values ranged from -6.90 to 2.55 with the majority having negative values. Crude oil samples from nine Penn sand reservoirs were analyzed for several properties pertinent to surfactant formulation for EOR application. These properties included equivalent alkane carbon numbers, total acid numbers,more » and viscosity. The brine samples from these same reservoirs were analyzed for several cations and for total dissolved solids. Surfactant formulations were successfully developed for eight reservoirs by the end of the project period. These formulations were comprised of a tertiary mixture of anionic surfactants. The identities of these surfactants are considered proprietary, but suffice to say the surfactants in each mixture were comprised of varying chemical structures. In addition to the successful development of surfactant formulations for EOR, there were also two successful single-well field tests conducted. There are many aspects that must be considered in the development and implementation of effective surfactant formulations. Taking into account these other aspects, there were four additional studies conducted during this project. These studies focused on the effect of the stability of surfactant formulations in the presence of polymers with an associated examination of polymer rheology, the effect of the presence of iron complexes in the brine on surfactant stability, the potential use of sacrificial agents in order to minimize the loss of surfactant to adsorption, and the effect of electrolytes on surfactant adsorption. In these last four studies the effects of such things as temperature, electrolyte concentration and the effect of different types of electrolytes were taken into consideration.« less

Rheo-optical near-infrared (NIR) spectroscopy study of partially miscible polymer blend of polymethyl methacrylate (PMMA) and polyethylene glycol (PEG)

NASA Astrophysics Data System (ADS)

Shinzawa, Hideyuki; Mizukado, Junji

2018-03-01

Tensile deformations of a partially miscible blend of polymethyl methacrylate (PMMA) and polyethylene glycol (PEG) is studied by a rheo-optical characterization near-infrared (NIR) technique to probe deformation behavior during tensile deformation. Sets of NIR spectra of the polymer samples were collected by using an acousto-optic tunable filter (AOTF) NIR spectrometer coupled with a tensile testing machine as an excitation device. While deformations of the samples were readily captured as strain-dependent NIR spectra, the entire feature of the spectra was overwhelmed with the baseline fluctuation induced by the decrease in the sample thickness and subsequent change in the light scattering. Several pretreatment techniques, including multiplicative scatter collection (MSC) and null-space projection, are subjected to the NIR spectra prior to the determination of the sequential order of the spectral intensity changes by two-dimensional (2D) correlation analysis. The comparison of the MSC and null-space projection provided an interesting insight into the system, especially deformation-induced variation of light scattering observed during the tensile testing of the polymer sample. In addition, the sequential order determined with the 2D correlation spectra revealed that orientation of a specific part of PMMA chain occurs before that of the others because of the interaction between Cdbnd O group of PMMA and terminal sbnd OH group of PEG.

Carbon Capture and Sequestration from a Hydrogen Production Facility in an Oil Refinery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Engels, Cheryl; Williams, Bryan, Valluri, Kiranmal; Watwe, Ramchandra

2010-06-21

The project proposed a commercial demonstration of advanced technologies that would capture and sequester CO2 emissions from an existing hydrogen production facility in an oil refinery into underground formations in combination with Enhanced Oil Recovery (EOR). The project is led by Praxair, Inc., with other project participants: BP Products North America Inc., Denbury Onshore, LLC (Denbury), and Gulf Coast Carbon Center (GCCC) at the Bureau of Economic Geology of The University of Texas at Austin. The project is located at the BP Refinery at Texas City, Texas. Praxair owns and operates a large hydrogen production facility within the refinery. Asmore » part of the project, Praxair would construct a CO2 capture and compression facility. The project aimed at demonstrating a novel vacuum pressure swing adsorption (VPSA) based technology to remove CO2 from the Steam Methane Reformers (SMR) process gas. The captured CO2 would be purified using refrigerated partial condensation separation (i.e., cold box). Denbury would purchase the CO2 from the project and inject the CO2 as part of its independent commercial EOR projects. The Gulf Coast Carbon Center at the Bureau of Economic Geology, a unit of University of Texas at Austin, would manage the research monitoring, verification and accounting (MVA) project for the sequestered CO2, in conjunction with Denbury. The sequestration and associated MVA activities would be carried out in the Hastings field at Brazoria County, TX. The project would exceed DOE?s target of capturing one million tons of CO2 per year (MTPY) by 2015. Phase 1 of the project (Project Definition) is being completed. The key objective of Phase 1 is to define the project in sufficient detail to enable an economic decision with regard to proceeding with Phase 2. This topical report summarizes the administrative, programmatic and technical accomplishments completed in Phase 1 of the project. It describes the work relative to project technical and design activities (associated with CO2 capture technologies and geologic sequestration MVA), and Environmental Information Volume. Specific accomplishments of this Phase include: 1. Finalization of the Project Management Plan 2. Development of engineering designs in sufficient detail for defining project performance and costs 3. Preparation of Environmental Information Volume 4. Completion of Hazard Identification Studies 5. Completion of control cost estimates and preparation of business plan During the Phase 1 detailed cost estimate, project costs increased substantially from the previous estimate. Furthermore, the detailed risk assessment identified integration risks associated with potentially impacting the steam methane reformer operation. While the Phase 1 work identified ways to mitigate these integration risks satisfactorily from an operational perspective, the associated costs and potential schedule impacts contributed to the decision not to proceed to Phase 2. We have concluded that the project costs and integration risks at Texas City are not commensurate with the potential benefits of the project at this time.« less

Essays on carbon policy and enhanced oil recovery

NASA Astrophysics Data System (ADS)

Cook, Benjamin R.

The growing concerns about climate change have led policy makers to consider various regulatory schemes designed to reduce the stock and growth of atmospheric CO2 concentrations while at the same time improving energy security. The most prominent proposals are the so called "cap-and-trade" frameworks which set aggregate emission levels for a jurisdiction and then issue or sell a corresponding number of allowances to emitters. Typically, these policy measures will also encourage the deployment of carbon capture and storage (CCS) in geological formations and mature oil fields through subsidies or other incentives. The ability to store CO 2 in mature oil fields through the deployment of CO2 enhanced oil recovery (CO2--EOR) is particularly attractive as it can simultaneously improve oil recovery at those fields, and serve as a possible financial bridge to the development of CO2 transportation infrastructure. The purpose of this research is to explore the impact that a tandem subsidy-tax policy regime may have on bargaining between emitters and sequestration providers, and also to identify oil units in Wyoming that can profitably undertake CO 2--EOR as a starting point for the build-out of CO2 pipelines. In the first essay an economics lab experiment is designed to simulate private bargaining between carbon emitters (such as power plants) and carbon sequestration sites when the emitter faces carbon taxes, sequestration subsidies or both. In a tax-subsidy policy regime the carbon tax (or purchased allowances) can be avoided by sequestering the carbon, and in some cases the emitter can also earn a subsidy to help pay for the sequestration. The main policy implications of the experiment results are that the sequestration market might be inefficient, and sequestration providers seem to have bargaining power sufficient to command high prices. This may lead to the integration of CO2 sources and sequestration sites, and reduced prices for the injectable CO2 purchased by oil operators for enhanced oil recovery. The second essay extends the CO2--EOR economic model described in a recent Energy Journal article by Klaas van 't Veld and Owen R. Phillips (2010). This essay takes a Monte Carlo approach to the economic scoping model which focuses more directly on the probabilistic outcomes for each individual oil field-reservoir combination (FRC). Using data on Wyoming oil fields the essay analyzes 197 FRCs in order to identify oil units with robust CO2--EOR profit potential over a wide range of uncertainty regarding future oil prices and reservoir characteristics. Of the 197 FRCs considered, 93 of them are found to meet an industry threshold IRR of 20 percent in at least half of scenarios with limited chance of actually taking losses. The third essay continues to employ the CO2--EOR economic scoping model, but focuses on Wyoming's aggregate EOR potential and attendant CO2 requirements. A similar Monte Carlo analysis is used to construct incremental oil "supply" and cumulative CO2 purchase "demand" curve estimates. Finally, the study uses a resampling technique similar to bootstrapping in order to create probabilistic distributions of Wyoming's aggregate EOR potential by assigning probabilities to individual oil prices. Although the data only covers oil fields with at least 5 MMbo of production, the analysis suggests around 768 MMbo of additional oil is likely to be recovered with CO2--EOR utilizing roughly 5.5 Tcf of injectable CO2.

Role of Thickness Confinement on Relaxations of the Fast Component in a Miscible A/B Blend

DOE Office of Scientific and Technical Information (OSTI.GOV)

Green, Peter; Sharma, Ravi P.; Dong, Ban Xuan

Spatial compositional heterogeneity strongly influences the dynamics of the A and B components of bulk miscible blends. Its effects are especially apparent in mixtures, such as poly(vinyl methyl ether) (PVME)/polystyrene (PS), where there exist significant disparities between the component glass transition temperatures (Tgs) and relaxation times. The relaxation processes characterized by distinct temperature dependencies and relaxation rates manifest different local compositional environments for temperatures above and below the glass transition temperature of the miscible blend. This same behavior is shown to exist in miscible PS/PVME films as thin as 100 nm. Moreover, in thin films, the characteristic segmental relaxation timesmore » t of the PVME component of miscible PVME/PS blends confined between aluminum (Al) substrates decrease with increasing molecular weight M of the PS component. These relaxation rates are film thickness dependent, in films up to a few hundred nanometers in thickness. This is in remarkable contrast to homopolymer films, where thickness confinement effects are apparent only on length scales on the order of nanometers. These surprisingly large length scales and M dependence are associated with the preferential interfacial enrichment - wetting layer formation - of the PVME component at the external Al interfaces, which alters the local spatial blend composition within the interior of the film. The implications are that the dynamics of miscible thin film blends are dictated in part by component Tg differences, disparities in component relaxation rates, component-substrate interactions, and chain lengths (entropy of mixing).« less

THE IMPACT OF POINT-SOURCE SUBTRACTION RESIDUALS ON 21 cm EPOCH OF REIONIZATION ESTIMATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trott, Cathryn M.; Wayth, Randall B.; Tingay, Steven J., E-mail: cathryn.trott@curtin.edu.au

Precise subtraction of foreground sources is crucial for detecting and estimating 21 cm H I signals from the Epoch of Reionization (EoR). We quantify how imperfect point-source subtraction due to limitations of the measurement data set yields structured residual signal in the data set. We use the Cramer-Rao lower bound, as a metric for quantifying the precision with which a parameter may be measured, to estimate the residual signal in a visibility data set due to imperfect point-source subtraction. We then propagate these residuals into two metrics of interest for 21 cm EoR experiments-the angular power spectrum and two-dimensional powermore » spectrum-using a combination of full analytic covariant derivation, analytic variant derivation, and covariant Monte Carlo simulations. This methodology differs from previous work in two ways: (1) it uses information theory to set the point-source position error, rather than assuming a global rms error, and (2) it describes a method for propagating the errors analytically, thereby obtaining the full correlation structure of the power spectra. The methods are applied to two upcoming low-frequency instruments that are proposing to perform statistical EoR experiments: the Murchison Widefield Array and the Precision Array for Probing the Epoch of Reionization. In addition to the actual antenna configurations, we apply the methods to minimally redundant and maximally redundant configurations. We find that for peeling sources above 1 Jy, the amplitude of the residual signal, and its variance, will be smaller than the contribution from thermal noise for the observing parameters proposed for upcoming EoR experiments, and that optimal subtraction of bright point sources will not be a limiting factor for EoR parameter estimation. We then use the formalism to provide an ab initio analytic derivation motivating the 'wedge' feature in the two-dimensional power spectrum, complementing previous discussion in the literature.« less

Monitoring of magnetic nano-particles in EOR by using the CSEM modeling and inversion.

NASA Astrophysics Data System (ADS)

Heo, J. Y.; KIM, S.; Jeong, G.; Hwang, J.; Min, D. J.

2016-12-01

EOR, which injects water, CO2, or other chemical components into reservoirs to increase the production rate of oil and gas, has widely been used. To promote efficiency of EOR, it is important to monitor distribution of injected materials in reservoirs. Using nano-particles in EOR has advantages that the size of particles is smaller than the pore and particles can be characterized by various physical properties. Specifically, if we use magnetic nano-particles, we can effectively monitor nano-particles by using the electromagnetic survey. CSEM, which can control the frequency range of source, is good to monitor magnetic nano-particles under various reservoir circumstances. In this study, we first perform numerical simulation of 3D CSEM for reservoir under production. In general, two wells are used for EOR: one is for injection, and the other is for extraction. We assume that sources are applied inside the injection well, and receivers are deployed inside the extraction well. To simulate the CSEM survey, we decompose the total fields into primary and secondary fields in Maxwell's equations. For the primary fields, we calculate the analytic solutions of the layered earth. With the calculated primary fields, we compute the secondary fields due to anomalies using the edge-based finite-element method. Finally, we perform electromagnetic inversion for both conductivity and permeability to trace the distribution of magnetic nano-particles. Since these two parameters react differently according to the frequency range of sources, we can effectively describe the distribution of magnetic nano-particles by considering two parameters at the same time. Acknowledgements This work was supported by the Korea Institute of Energy Technology Evaluation and Planning(KETEP) and the Ministry of Trade, Industry & Energy(MOTIE) of the Republic of Korea (No. 20168510030830), and by the International Cooperation (No. 2012-8510030010) of KETEP, and by the Dual Use Technology Program, granted financial resource from the MOTIE.

Influence of Miscibility Phenomenon on Crystalline Polymorph Transition in Poly(Vinylidene Fluoride)/Acrylic Rubber/Clay Nanocomposite Hybrid

PubMed Central

Abolhasani, Mohammad Mahdi; Naebe, Minoo; Jalali-Arani, Azam; Guo, Qipeng

2014-01-01

In this paper, intercalation of nanoclay in the miscible polymer blend of poly(vinylidene fluoride) (PVDF) and acrylic rubber(ACM) was studied. X-ray diffraction was used to investigate the formation of nanoscale polymer blend/clay hybrid. Infrared spectroscopy and X-ray analysis revealed the coexistence of β and γ crystalline forms in PVDF/Clay nanocomposite while α crystalline form was found to be dominant in PVDF/ACM/Clay miscible hybrids. Flory-Huggins interaction parameter (B) was used to further explain the miscibility phenomenon observed. The B parameter was determined by combining the melting point depression and the binary interaction model. The estimated B values for the ternary PVDF/ACM/Clay and PVDF/ACM pairs were all negative, showing both proper intercalation of the polymer melt into the nanoclay galleries and the good miscibility of PVDF and ACM blend. The B value for the PVDF/ACM blend was almost the same as that measured for the PVDF/ACM/Clay hybrid, suggesting that PVDF chains in nanocomposite hybrids interact with ACM chains and that nanoclay in hybrid systems is wrapped by ACM molecules. PMID:24551141

Vapor condensation onto a non-volatile liquid drop

DOE Office of Scientific and Technical Information (OSTI.GOV)

Inci, Levent; Bowles, Richard K., E-mail: richard.bowles@usask.ca

2013-12-07

Molecular dynamics simulations of miscible and partially miscible binary Lennard–Jones mixtures are used to study the dynamics and thermodynamics of vapor condensation onto a non-volatile liquid drop in the canonical ensemble. When the system volume is large, the driving force for condensation is low and only a submonolayer of the solvent is adsorbed onto the liquid drop. A small degree of mixing of the solvent phase into the core of the particles occurs for the miscible system. At smaller volumes, complete film formation is observed and the dynamics of film growth are dominated by cluster-cluster coalescence. Mixing into the coremore » of the droplet is also observed for partially miscible systems below an onset volume suggesting the presence of a solubility transition. We also develop a non-volatile liquid drop model, based on the capillarity approximations, that exhibits a solubility transition between small and large drops for partially miscible mixtures and has a hysteresis loop similar to the one observed in the deliquescence of small soluble salt particles. The properties of the model are compared to our simulation results and the model is used to study the formulation of classical nucleation theory for systems with low free energy barriers.« less

Miscibility of ethyl cellulose/copolyamide6/66/1010 blends by viscometry and refractive index method

NASA Astrophysics Data System (ADS)

Zhang, Xiuzhen; Shen, Yuhua; Xie, Anjian; Gao, Sulian; Xing, Zhiying

2011-04-01

The miscibility of ethyl cellulose (EC)/copolyamide6/66/1010 (PA-130) in formic acid is studied by viscometry and refractive index techniques at 25°C. Using viscosity data, the criteria Δ b, Δ b', Δ[η]m, interaction parameter μ, β and thermodynamic parameter α are calculated. These investigations indicate that blend of EC/PA-130 is miscible when the ethyl cellulose content is more than 50 wt % in the blend. Further the result was also confirmed by refractive index measurements.

The quarantine bay 4RC CO/sub 2/ WAG pilot project: A postflood evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsie, J.C.; Moore, J.S.

1988-08-01

This paper reviews the design, implementation, and performance of a miscible CO/sub 2/ water-alternating-gas (WAG) project in a U.S. gulf coast reservoir. The field-test obtained since the inception of the project in Oct. 1981 are presented, and solutions to such operational problems as downhole corrosion are discussed. Remarkable project response and recovery demonstrated that the CO/sub 2/ WAG process is technically viable for mobilizing considerable amounts of residual oil from watered-out Miocene reservoirs. A 16.9% recovery or original oil in place (OOIP) was obtained with a CO/sub 2/ slug size of 18.9% original HCPV. The CO/sub 2/ requirement was 2.57more » Mcf/bbl (458 m/sup 3//m/sup 3/) of oil recovered.« less

The Quarantine Bay 4RC CO/sub 2/-WAG pilot project: A post-flood evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsie, J.C.; Moore, J.S.

1986-01-01

This paper reviews the design, implementation, and performance of a miscible CO/sub 2/ - WAG (water-alternating-gas) project in a Gulf Coast reservoir. The field test data obtained since the inception of the project in October 1981 are presented, and solutions to operational problems such as downhole corrosion are discussed. Remarkable project response and recovery demonstrated that the CO/sub 2/-WAG process is technically viable for mobilizing considerable amounts of residual oil from watered-out Miocene reservoirs. A 14.7% recovery of original-oil-in-place (OOIP) was obtained using a CO/sub 2/ slug size of 18.9% original hydrocarbon pore volume (HCPV). The CO/sub 2/ requirement wasmore » 2.95 Mcf/bbl (531 m/sup 3//m/sup 3/) of oil recovered.« less

Viscous fingering with partially miscible fluids

NASA Astrophysics Data System (ADS)

Fu, Xiaojing; Cueto-Felgueroso, Luis; Juanes, Ruben

2017-10-01

Viscous fingering—the fluid-mechanical instability that takes place when a low-viscosity fluid displaces a high-viscosity fluid—has traditionally been studied under either fully miscible or fully immiscible fluid systems. Here we study the impact of partial miscibility (a common occurrence in practice) on the fingering dynamics. Through a careful design of the thermodynamic free energy of a binary mixture, we develop a phase-field model of fluid-fluid displacements in a Hele-Shaw cell for the general case in which the two fluids have limited (but nonzero) solubility into one another. We show, by means of high-resolution numerical simulations, that partial miscibility exerts a powerful control on the degree of fingering: fluid dissolution hinders fingering while fluid exsolution enhances fingering. We also show that, as a result of the interplay between compositional exchange and the hydrodynamic pattern-forming process, stronger fingering promotes the system to approach thermodynamic equilibrium more quickly.

Impact of sodium chloride on the expansion of a liquid-liquid miscibility gap in an API/water system. Case study of Brivaracetam.

PubMed

Couvrat, Nicolas; Mahieux, Julien; Fours, Baptiste; Cartigny, Yohann; Schenkel, Eric; Aerts, Luc; Quéré, Luc; Coquerel, Gérard

2016-12-30

Brivaracetam, or (2S)-2-[(4R)-2-oxo-4-propyl-pyrrolidin-1-yl] butanamide, is an active pharmaceutical ingredient designed for the treatment of epilepsy. During the development of the IV administration mode, a liquid-liquid miscibility gap has been observed with pure water, isotonic and hypertonic solutions (vehicle at 0.9% w/w and 5%w/w NaCl respectively). The study reveals that the NaCl concentration has a direct impact on the extent of the demixing domain; from a sub-micronic demixing in pure water towards a macroscopic miscibility gap in hypertonic aqueous solutions. The thorough exploration of these heterogeneous equilibria led to define experimental parameters for safe IV injections without risk of liquid - liquid miscibility gap at 37°C. Copyright © 2016 Elsevier B.V. All rights reserved.

Influence of water-miscible cutting fluid on tool wear behavior of various coated high-speed steel tools in hobbing

NASA Astrophysics Data System (ADS)

Sato, Yuta; Matsuoka, Hironori; Kubo, Akio; Ono, Hajime; Ryu, Takahiro; Qiu, Hua; Nakae, Takashi; Shuto, Shuichi; Watanabe, Suguru; Anan, Ruito

2017-04-01

This paper deals with the influence of water-miscible cutting fluid on tool life (flank wear) compared with that with dry cutting and water-insoluble cutting oil in hobbing. Experiments were conducted by simulating hobbing by fly tool cutting on a milling machine. The following results were clarified. (1) The water-miscible cutting fluid used in the test prolongs the tool life for TiN-, TiAlN-, TiSiN- and AlCrSiN-coated tools in comparison with that obtained by dry cutting and water-insoluble cutting oil. (2) It was presumed that the tool wear decreases and the tool life is improved by the lubrication effect of the synthetic lubrication additive, mineral oil and sulfuric EP additive contained in the water-miscible cutting fluid, and also by the cooling effect.

Pt/Mo 2C/C-cp as a highly active and stable catalyst for ethanol electrooxidation

DOE PAGES

Lin, Lili; Sheng, Wenchao; Yao, Siyu; ...

2017-02-09

Here, a Pt/Mo 2C/C-cp electrocatalyst with optimized Pt-Mo 2C chemical bonding is synthesized and evaluated for the ethanol oxidation reaction (EOR). The chemical bonding of Mo 2C to Pt particles renders exceptional EOR activity at low potentials, which is 15 and 2.5 times higher than Pt/C and commercial 40% PtRu/C, respectively, at 0.6 V (vs. RHE). The stability of the Pt/Mo 2C/C-cp electrocatalyst is comparable to the commercial 40% PtRu/C catalyst. CO stripping test demonstrates the existence of highly active sites for CO oxidation on the Pt/Mo 2C/C-cp catalyst. In-situ infrared spectroscopic studies of EOR reveal that the excellent anti-poisoningmore » ability of the Pt/Mo 2C/C-cp catalyst is related to the relatively weak binding of carbonyl intermediates over the Pt/Mo 2C/C-cp catalysts.« less

Pt/Mo 2C/C-cp as a highly active and stable catalyst for ethanol electrooxidation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Lili; Sheng, Wenchao; Yao, Siyu

Here, a Pt/Mo 2C/C-cp electrocatalyst with optimized Pt-Mo 2C chemical bonding is synthesized and evaluated for the ethanol oxidation reaction (EOR). The chemical bonding of Mo 2C to Pt particles renders exceptional EOR activity at low potentials, which is 15 and 2.5 times higher than Pt/C and commercial 40% PtRu/C, respectively, at 0.6 V (vs. RHE). The stability of the Pt/Mo 2C/C-cp electrocatalyst is comparable to the commercial 40% PtRu/C catalyst. CO stripping test demonstrates the existence of highly active sites for CO oxidation on the Pt/Mo 2C/C-cp catalyst. In-situ infrared spectroscopic studies of EOR reveal that the excellent anti-poisoningmore » ability of the Pt/Mo 2C/C-cp catalyst is related to the relatively weak binding of carbonyl intermediates over the Pt/Mo 2C/C-cp catalysts.« less

Three approaches for estimating recovery factors in carbon dioxide enhanced oil recovery

USGS Publications Warehouse

Verma, Mahendra K.

2017-07-17

PrefaceThe Energy Independence and Security Act of 2007 authorized the U.S. Geological Survey (USGS) to conduct a national assessment of geologic storage resources for carbon dioxide (CO2) and requested the USGS to estimate the “potential volumes of oil and gas recoverable by injection and sequestration of industrial carbon dioxide in potential sequestration formations” (42 U.S.C. 17271(b)(4)). Geologic CO2 sequestration associated with enhanced oil recovery (EOR) using CO2 in existing hydrocarbon reservoirs has the potential to increase the U.S. hydrocarbon recoverable resource. The objective of this report is to provide detailed information on three approaches that can be used to calculate the incremental recovery factors for CO2-EOR. Therefore, the contents of this report could form an integral part of an assessment methodology that can be used to assess the sedimentary basins of the United States for the hydrocarbon recovery potential using CO2-EOR methods in conventional oil reservoirs.

Anti-fouling response of gold-carbon nanotubes composite for enhanced ethanol electrooxidation

NASA Astrophysics Data System (ADS)

Sai Siddhardha, R. S.; Anupam Kumar, Manne; Lakshminarayanan, V.; Ramamurthy, Sai Sathish

2014-12-01

We report the synthesis of gold carbon nanotubes composite through a one-pot surfactant free approach and its utility for ethanol electrooxidation reaction (EOR). The method involves the application of laser ablation for nanoparticle synthesis and simultaneous assembly of these on carbon nanotubes. The catalyst has been characterized by field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDAX) and UV-vis spectroscopic techniques. A systematic study of gold carbon nanotubes modified carbon paste electrode for EOR has been pursued. The kinetic study revealed the excellent stability of the modified electrode even after 200 cycles of EOR and with an Arrhenius energy as low as ∼28 kJ mol-1. Tafel slopes that are the measure of electrode activity have been monitored as a function of temperature of the electrolyte. The results indicate that despite an increase in the reaction rate with temperature, the electrode surface has not been significantly passivated by carbonaceous species produced at high temperatures.

Integrated Mid-Continent Carbon Capture, Sequestration & Enhanced Oil Recovery Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brian McPherson

2010-08-31

A consortium of research partners led by the Southwest Regional Partnership on Carbon Sequestration and industry partners, including CAP CO2 LLC, Blue Source LLC, Coffeyville Resources, Nitrogen Fertilizers LLC, Ash Grove Cement Company, Kansas Ethanol LLC, Headwaters Clean Carbon Services, Black & Veatch, and Schlumberger Carbon Services, conducted a feasibility study of a large-scale CCS commercialization project that included large-scale CO{sub 2} sources. The overall objective of this project, entitled the 'Integrated Mid-Continent Carbon Capture, Sequestration and Enhanced Oil Recovery Project' was to design an integrated system of US mid-continent industrial CO{sub 2} sources with CO{sub 2} capture, and geologicmore » sequestration in deep saline formations and in oil field reservoirs with concomitant EOR. Findings of this project suggest that deep saline sequestration in the mid-continent region is not feasible without major financial incentives, such as tax credits or otherwise, that do not exist at this time. However, results of the analysis suggest that enhanced oil recovery with carbon sequestration is indeed feasible and practical for specific types of geologic settings in the Midwestern U.S.« less

LOW-FREQUENCY OBSERVATIONS OF THE MOON WITH THE MURCHISON WIDEFIELD ARRAY

DOE Office of Scientific and Technical Information (OSTI.GOV)

McKinley, B.; Briggs, F.; Kaplan, D. L.

2013-01-01

A new generation of low-frequency radio telescopes is seeking to observe the redshifted 21 cm signal from the epoch of reionization (EoR), requiring innovative methods of calibration and imaging to overcome the difficulties of wide-field low-frequency radio interferometry. Precise calibration will be required to separate the expected small EoR signal from the strong foreground emission at the frequencies of interest between 80 and 300 MHz. The Moon may be useful as a calibration source for detection of the EoR signature, as it should have a smooth and predictable thermal spectrum across the frequency band of interest. Initial observations of themore » Moon with the Murchison Widefield Array 32 tile prototype show that the Moon does exhibit a similar trend to that expected for a cool thermally emitting body in the observed frequency range, but that the spectrum is corrupted by reflected radio emission from Earth. In particular, there is an abrupt increase in the observed flux density of the Moon within the internationally recognized frequency modulated (FM) radio band. The observations have implications for future low-frequency surveys and EoR detection experiments that will need to take this reflected emission from the Moon into account. The results also allow us to estimate the equivalent isotropic power emitted by the Earth in the FM band and to determine how bright the Earth might appear at meter wavelengths to an observer beyond our own solar system.« less

Simultaneously constraining the astrophysics of reionization and the epoch of heating with 21CMMC

NASA Astrophysics Data System (ADS)

Greig, Bradley; Mesinger, Andrei

2017-12-01

The cosmic 21 cm signal is set to revolutionize our understanding of the early Universe, allowing us to probe the 3D temperature and ionization structure of the intergalactic medium (IGM). It will open a window on to the unseen first galaxies, showing us how their UV and X-ray photons drove the cosmic milestones of the epoch of reionization (EoR) and epoch of heating (EoH). To facilitate parameter inference from the 21 cm signal, we previously developed 21CMMC: a Monte Carlo Markov Chain sampler of 3D EoR simulations. Here, we extend 21CMMC to include simultaneous modelling of the EoH, resulting in a complete Bayesian inference framework for the astrophysics dominating the observable epochs of the cosmic 21 cm signal. We demonstrate that second-generation interferometers, the Hydrogen Epoch of Reionization Array and Square Kilometre Array will be able to constrain ionizing and X-ray source properties of the first galaxies with a fractional precision of the order of ∼1-10 per cent (1σ). The ionization history of the Universe can be constrained to within a few percent. Using our extended framework, we quantify the bias in EoR parameter recovery incurred by the common simplification of a saturated spin temperature in the IGM. Depending on the extent of overlap between the EoR and the EoH, the recovered astrophysical parameters can be biased by ∼3σ-10σ.

Ultrathin layered double hydroxide nanosheets with Ni(III) active species obtained by exfoliation for highly efficient ethanol electrooxidation

PubMed Central

Xu, Liang; Wang, Zhe; Chen, Xu; Qu, Zongkai; Li, Feng; Yang, Wensheng

2018-01-01

The development of non-precious metal electrocatalysts for renewable energy conversion and storage is compelling but greatly challenging due to low activity of the existing catalysts. Herein, the ultrathin NiAl-layered double hydroxide nanosheets (NiAl-LDH-NSs) are prepared by simple liquid-exfoliation of bulk NiAl-LDHs and first used as ethanol electrooxidation catalysts. The ultrathin two-dimensional (2D) structure ensures that the LDH nanosheets expose a greater number of active sites. More importantly, much Ni(III) active species (NiOOH) in the ultrathin nanosheets are formed by the exfoliation process, which play an authentic catalytic role in the ethanol oxidation reaction (EOR). The presence of NiOOH remarkably improves the reactivity and electrical conductivity of LDH nanosheets. These synergistic effects lead to strikingly more than 30 times enhanced EOR activity of NiAl-LDH-NSs compared to bulk NiAl-LDHs. The obtained electrocatalytic activity is also much better than those of most Ni- and LDH-based EOR catalysts reported to date. In addition, the ultrathin NiAl-LDH-NS electrocatalyst also exhibits good long-term stability (maintain 81.8% of the original value after 10000 s). This study not only provides a highly competitive EOR catalyst, but also opens new avenues toward the design of highly efficient electrode materials that have various potential applications in supercapacitor, Ni-MH battery and other electrocatalytic systems. PMID:29622818

Are we witnessing the epoch of reionisation at z = 7.1 from the spectrum of J1120+0641?

NASA Astrophysics Data System (ADS)

Greig, Bradley; Mesinger, Andrei; Haiman, Zoltán; Simcoe, Robert A.

2017-04-01

We quantify the presence of Lyα damping wing absorption from a partially neutral intergalactic medium (IGM) in the spectrum of the z = 7.08 QSO, ULASJ1120+0641. Using a Bayesian framework, we simultaneously account for uncertainties in: (I) the intrinsic QSO emission spectrum; and (II) the distribution of cosmic H I patches during the epoch of reionization (EoR). For (I), we use a new intrinsic Lyα emission line reconstruction method, sampling a covariance matrix of emission line properties built from a large data base of moderate-z QSOs. For (II), we use the Evolution of 21-cm Structure (EOS; Mesinger et al.) simulations, which span a range of physically motivated EoR models. We find strong evidence for the presence of damping wing absorption redward of Lyα (where there is no contamination from the Lyα forest). Our analysis implies that the EoR is not yet complete by z = 7.1, with the volume-weighted IGM neutral fraction constrained to \\bar{x}_{H I} = 0.40^{+0.21 }_{ -0.19} at 1σ (\\bar{x}_{H I} = 0.40^{+0.41 }_{ -0.32} at 2σ). This result is insensitive to the EoR morphology. Our detection of significant neutral H I in the IGM at z = 7.1 is consistent with the latest Planck 2016 measurements of the CMB Thompson scattering optical depth.

COSOLVENCY AND SOPRTION OF HYDROPHOBIC ORGANIC CHEMICALS

EPA Science Inventory

Sorption of hydrophobic organic chemicals (HOCs) by two soils was measured from mixed solvents containing water plus completely miscible organic solvents (CMOSs) and partially miscible organic solvents (PMOSs). The utility of the log-linear cosolvency model for predicting HOC sor...

Small Scale Field Test Demonstrating CO 2 Sequestration In Arbuckle Saline Aquifer And By CO 2-Eor At Wellington Field, Sumner County, Kansas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holubnyak, Yevhen Eugene; Watney, Lynn; Hollenbach, Jennifer

The objectives of this project are to understand the processes that occur when a maximum of 70,000 metric tonnes of CO2 are injected into two different formations to evaluate the response in different lithofacies and depositional environments. The evaluation will be accomplished through the use of both in situ and indirect MVA (monitoring, verification, and accounting) technologies. The project will optimize for carbon storage accounting for 99% of the CO2 using lab and field testing and comprehensive characterization and modeling techniques. Site characterization and CO2 injection should demonstrate state-of-the-art MVA tools and techniques to monitor and visualize the injected CO2more » plume and to refine geomodels developed using nearly continuous core, exhaustive wireline logs, and well tests and a multi-component 3-D seismic survey. Reservoir simulation studies will map the injected CO2 plume and estimate tonnage of CO2 stored in solution, as residual gas, and by mineralization and integrate MVA results and reservoir models shall be used to evaluate CO2 leakage. A rapid-response mitigation plan was developed to minimize CO2 leakage and provide a comprehensive risk management strategy. The CO2 was intended to be supplied from a reliable facility and have an adequate delivery and quality of CO2. However, several unforeseen circumstances complicated this plan: (1) the initially negotiated CO2 supply facility went offline and contracts associated with CO2 supply had to be renegotiated, (2) a UIC Class VI permit proved to be difficult to obtain due to the experimental nature of the project. Both subjects are detailed in separate deliverables attached to this report. The CO2 enhanced oil recovery (EOR) and geologic storage in Mississippian carbonate reservoir was sucessully deployed. Approximately 20,000 metric tons of CO2 was injected in the upper part of the Mississippian reservoir to verify CO2 EOR viability in carbonate reservoirs and evaluate a potential of transitioning to geologic CO2 storage through EOR. A total of 1,101 truckloads, 19,803 metric tons—an average of 120 tonnes per day—were delivered over the course of injection that lasted from January 9 to June 21, 2016. After cessation of CO2 injection, the KGS 2-32 well was converted to water injector and continues to operate. CO2 EOR progression in the field was monitored weekly with fluid level, temperature, and production recording and formation fluid composition sampling. It is important to note that normally, CO2 EOR pilots are less efficient than commercial operations due to lack of directional and precise well control, lack of surface facilities for CO2 recycling, and other factors. As a result of this pilot CO2 injection, the observed incremental average oil production increase was ~68% with only ~18% of injected CO2 produced back. Decline curve analysis forecasts of additional cumulative oil produced were 32.44M STB to the end of 2027. Wellington Mississippian pilot efficiency by the end of forecast calculations is 11 MCF per barrel of produced oil. Using 32M STB oil production and $1,964,063 cost of CO2, CO2 EOR cost per barrel of oil production is ~$60. Simple but robust monitoring technologies proved to be very efficient in detecting and locating CO2. High CO2 reservoir retentions with low yields within an actively producing field could help to estimate real-world risks of CO2 geological storage for future projects. The Wellington Field CO2 EOR was executed in a controlled environment with high efficiency. This case study proves that CO2 EOR could be successfully applied in Kansas carbonate reservoirs if CO2 sources and associated infrastructure are available. Recent developments in unconventional resources development in Mid-Continent USA and associated large volume disposal of backflow water and the resulting seismic activity have brought more focus and attention to the Arbuckle Group in southern Kansas. Despite the commercial interest, limited essential information about reservoir properties and structural elements has impeded the management and regulation of disposal, an issue brought to the forefront by recent seismicity in and near areas of large volumes and rates of brine disposal. The Kansas Geological Survey (KGS) collected, compiled, and analyzed available data, including well logs, core data, step rate tests, drill stem tests, 2-D and 3-D seismic data, water level measurements, and others types of data. Several exploratory wells were drilled and core was collected and modern suites of logs were analyzed. Reservoir properties were populated into several site-specific geological models. The geological models illustrate the highly heterogeneous nature of the Arbuckle Group. Vertical and horizontal variability results in several distinct hydro-stratigraphic units that are the result of both depositional and diagenetic processes. During the course of this project, it has been demonstrated that advanced seismic interpretation methods can be used successfully for characterization of the Mississippian reservoir and Arbuckle saline aquifer. Analysis of post-stack 3-D seismic data at the Mississippian reservoir showed the response of a gradational velocity transition. Pre-stack gather analysis showed that porosity zones of the Mississippian and Arbuckle reservoirs exhibit characteristic amplitude versus offset (AVO) response. Simultaneous AVO inversion estimated P- and S-impedances. The 3-D survey gather azimuthal anisotropy analysis (AVAZ) provided information about the fault and fracture network and showed good agreement to the regional stress field and well data. Mississippian reservoir porosity and fracture predictions agreed well with the observed mobility of injected CO2 in KGS well 2-32. Fluid substitution modeling predicted acoustic impedance reduction in the Mississippian carbonate reservoir introduced by the presence of CO2. Seismicity in the United States midcontinent has increased by orders of magnitude over the past decade. Spatiotemporal correlations of seismicity to wastewater injection operations have suggested that injection-related pore fluid pressure increases are inducing the earthquakes. In this investigation, we examine earthquake occurrence in southern Kansas and northern Oklahoma and its relation to the change in pore pressure. The main source of data comes from the Wellington Array in the Wellington oil field, in Sumner County, Kansas, which has monitored for earthquakes in central Sumner County, Kansas, since early 2015. The seismometer array was established to monitor CO2 injection operations at Wellington Field. Although no seismicity was detected in association with the spring 2016 Mississippian CO2 injection, the array has recorded more than 2,500 earthquakes in the region and is providing valuable understanding to induced seismicity. A catalog of earthquakes was built from this data and was analyzed for spatial and temporal changes, stress information, and anisotropy information. The region of seismic concern has been shown to be expanding through use of the Wellington earthquake catalog, which has revealed a northward progression of earthquake activity reaching the metropolitan area of Wichita. The stress orientation was also calculated from this earthquake catalog through focal mechanism inversion. The calculated stress orientation was confirmed through comparison to other stress measurements from well data and previous earthquake studies in the region. With this knowledge of the stress orientation, the anisotropy in the basement could be understood. This allowed for the anisotropy measurements to be correlated to pore pressure increases. The increase in pore pressure was monitored through time-lapse shear-wave anisotropy analysis. Since the onset of the observation period in 2010, the orientation of the fast shear wave has rotated 90°, indicating a change associated with critical pore pressure build up. The time delay between fast and slow shear wave arrivals has increased, indicating a corresponding increase in anisotropy induced by pore pressure rise. In-situ near-basement fluid pressure measurements corroborate the continuous pore pressure increase revealed by the shear-wave anisotropy analysis over the earthquake monitoring period. This research is the first to identify a change in pore fluid pressure in the basement using seismological data and it was recently published in the AAAS journal Science Advances (Nolte et al., 2017). The shear-wave splitting analysis is a novel application of the technique, which can be used in other regions to identify an increase in pore pressure. This increasing pore fluid pressure has become more regionally extensive as earthquakes are occurring in southern Kansas, where they previously were absent. These monitoring techniques and analyses provide new insight into mitigating induced seismicity’s impact on society.« less

Miscibility and Thermodynamics of Mixing of Different Models of Formamide and Water in Computer Simulation.

PubMed

Kiss, Bálint; Fábián, Balázs; Idrissi, Abdenacer; Szőri, Milán; Jedlovszky, Pál

2017-07-27

The thermodynamic changes that occur upon mixing five models of formamide and three models of water, including the miscibility of these model combinations itself, is studied by performing Monte Carlo computer simulations using an appropriately chosen thermodynamic cycle and the method of thermodynamic integration. The results show that the mixing of these two components is close to the ideal mixing, as both the energy and entropy of mixing turn out to be rather close to the ideal term in the entire composition range. Concerning the energy of mixing, the OPLS/AA_mod model of formamide behaves in a qualitatively different way than the other models considered. Thus, this model results in negative, while the other ones in positive energy of mixing values in combination with all three water models considered. Experimental data supports this latter behavior. Although the Helmholtz free energy of mixing always turns out to be negative in the entire composition range, the majority of the model combinations tested either show limited miscibility, or, at least, approach the miscibility limit very closely in certain compositions. Concerning both the miscibility and the energy of mixing of these model combinations, we recommend the use of the combination of the CHARMM formamide and TIP4P water models in simulations of water-formamide mixtures.

Polymer-fullerene miscibility: a metric for screening new materials for high-performance organic solar cells.

PubMed

Treat, Neil D; Varotto, Alessandro; Takacs, Christopher J; Batara, Nicolas; Al-Hashimi, Mohammed; Heeney, Martin J; Heeger, Alan J; Wudl, Fred; Hawker, Craig J; Chabinyc, Michael L

2012-09-26

The improvement of the power conversion efficiency (PCE) of polymer bulk heterojunction (BHJ) solar cells has generally been achieved through synthetic design to control frontier molecular orbital energies and molecular ordering of the electron-donating polymer. An alternate approach to control the PCE of a BHJ is to tune the miscibility of the fullerene and a semiconducting polymer by varying the structure of the fullerene. The miscibility of a series of 1,4-fullerene adducts in the semiconducting polymer, poly(3-hexylselenophene), P3HS, was measured by dynamic secondary ion mass spectrometry using a model bilayer structure. The microstructure of the bilayer was investigated using high-angle annular dark-field scanning transmission microscopy and linked to the polymer-fullerene miscibility. Finally, P3HS:fullerene BHJ solar cells were fabricated from each fullerene derivative, enabling the correlation of the active layer microstructure to the charge collection efficiency and resulting PCE of each system. The volume fraction of polymer-rich, fullerene-rich, and polymer-fullerene mixed domains can be tuned using the miscibility leading to improvement in the charge collection efficiency and PCE in P3HS:fullerene BHJ solar cells. These results suggest a rational approach to the design of fullerenes for improved BHJ solar cells.

Miscibility comparison for three refrigerant mixtures and four component refrigerants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kang, H.M.; Pate, M.B.

1999-07-01

Miscibility data were taken and compared for seven different refrigerants when mixed with the same polyol ester (POE) lubricant. Four of the seven refrigerants were single-component refrigerants while three of the refrigerants were mixtures composed of various combinations of the pure refrigerants. The purpose of this research was to investigate the difference in miscibility characteristics between refrigerant mixtures and their respective component refrigerants. The POE lubricant was a penta erythritol mixed-acid type POE which has a viscosity ISO32. The four pure refrigerants were R-32, R-125, R-134a, and R-143a and the three refrigerant mixtures were R-404A, R407C, and R-410A. The miscibilitymore » tests were performed in a test facility consisting of a series of miniature test cells submerged in a constant temperature bath. The test cells were constructed to allow for complete visibility of the refrigerant/lubricant mixtures under all test conditions. The tests were performed over a concentration range of 0 to 100% and a temperature range of {minus}40 to 194 F. The miscibility test results for refrigerant mixtures are compared to component refrigerants. In all cases, the refrigerant mixtures appear to have better miscibility than their most immiscible pure component.« less

An investigation of the thermodynamic miscibility between VeTPGS and polymers.

PubMed

Li, Jinjiang; Chiappetta, Doris

2008-02-28

Within the past decade, more than half of the drug candidates generated are poorly water soluble and therefore overcoming the low aqueous solubility of drug candidates becomes critical for product development. Vitamin E TPGS (VeTPGS), a non-ionic surfactant, has been used in both liquid and solid dosage forms to solubilize compounds and improve their bioavailability. To prepare solid dosage forms using VeTPGS, VeTPGS is often mixed with other excipients, mostly polymers. However, there is still a lack of understanding of miscibility between VeTPGS and polymers from a thermodynamic point of view. In this paper, the miscibility of VeTPGS with polymers has been studied in the light of the Flory-Huggins (F-H) theory with an objective to understand the effect of dispersion forces (solubility parameter) and nondispersive interactions on the miscibility between VeTPGS and polymers. A series of polymers with similar solubility parameters and structure similarity were selected. Binary blends of polymers and VeTPGS were prepared using a vapor evaporation technique followed by XRPD, DSC, and SEM characterization. Results suggest that the miscibility between VeTPGS and PMMA is very likely due to a specific interaction between the hydrophobic portion of VeTPGS (Vitamin E) and PMMA.

General introduction and recovery factors

USGS Publications Warehouse

Verma, Mahendra K.

2017-07-17

IntroductionThe U.S. Geological Survey (USGS) compared methods for estimating an incremental recovery factor (RF) for the carbon dioxide enhanced oil recovery (CO2-EOR) process involving the injection of CO2 into oil reservoirs. This chapter first provides some basic information on the RF, including its dependence on various reservoir and operational parameters, and then discusses the three development phases of oil recovery—primary, second­ary, and tertiary (EOR). It ends with a brief discussion of the three approaches for estimating recovery factors, which are detailed in subsequent chapters.

MISCIBILITY, SOLUBILITY, AND VISCOSITY MEASUREMENTS FOR R-236EA WITH POTENTIAL LUBRICANTS

EPA Science Inventory

The report gives results of miscibility, solubility, and viscosity measurements of refrigerant R-236ea with three potential lubricants. (NOTE: The data were needed to determine the suitability of refrigerant/lubricant combinations for use in refrigeration systems.) The lubricants...

Full Characterization of CO2-Oil Properties On-Chip: Solubility, Diffusivity, Extraction Pressure, Miscibility, and Contact Angle.

PubMed

Sharbatian, Atena; Abedini, Ali; Qi, ZhenBang; Sinton, David

2018-02-20

Carbon capture, storage, and utilization technologies target a reduction in net CO 2 emissions to mitigate greenhouse gas effects. The largest such projects worldwide involve storing CO 2 through enhanced oil recovery-a technologically and economically feasible approach that combines both storage and oil recovery. Successful implementation relies on detailed measurements of CO 2 -oil properties at relevant reservoir conditions (P = 2.0-13.0 MPa and T = 23 and 50 °C). In this paper, we demonstrate a microfluidic method to quantify the comprehensive suite of mutual properties of a CO 2 and crude oil mixture including solubility, diffusivity, extraction pressure, minimum miscibility pressure (MMP), and contact angle. The time-lapse oil swelling/extraction in response to CO 2 exposure under stepwise increasing pressure was quantified via fluorescence microscopy, using the inherent fluorescence property of the oil. The CO 2 solubilities and diffusion coefficients were determined from the swelling process with measurements in strong agreement with previous results. The CO 2 -oil MMP was determined from the subsequent oil extraction process with measurements within 5% of previous values. In addition, the oil-CO 2 -silicon contact angle was measured throughout the process, with contact angle increasing with pressure. In contrast with conventional methods, which require days and ∼500 mL of fluid sample, the approach here provides a comprehensive suite of measurements, 100-fold faster with less than 1 μL of sample, and an opportunity to better inform large-scale CO 2 projects.

MISCIBILITY, SOLUBILITY, VISCOSITY, AND DENSITY MEASUREMENTS FOR R-236FA WITH POTENTIAL LUBRICANTS

EPA Science Inventory

The report gives results of miscibility, solubility, viscosity, and density measurements for refrigerant R-236fa and two potential lubricants . (The data are needed to determine the suitability of refrigerant/lubricant combinations for use in refrigeration systems.) The tested oi...

Miscibility, solubility, viscosity, and density measurements for R-236ea with four different Exxon lubricants. Final report, March 1995-March 1997

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kang, H.M.; Pate, M.B.

1999-06-15

The report discusses miscibility, solubility, viscosity, and density data for the refrigerant hydrofluorocarbon (HFC)-236ea (or R-236ea) and four lubricants supplied by Exxon Corporation. The miscibility tests were performed in a test facility consisting of a series of miniature test cells submerged in a constant temperature bath, precisely controlled over a range of {minus}50 to 90 C. Critical solution temperatures obtained from the miscibility data are presented for each refrigerant/lubricant combination. Data for the R-236ea in each of the test lubricants have been collected for refrigerant concentrations of 10--90%. The raw data have been presented, and the results have been summarized.more » Solubility, viscosity, and density data were also obtained for R-236ea mixed with the same four oils for a refrigerant concentration range of 0--40 wt% refrigerant over a temperature range of 30--100 C.« less

Flash-point prediction for binary partially miscible mixtures of flammable solvents.

PubMed

Liaw, Horng-Jang; Lu, Wen-Hung; Gerbaud, Vincent; Chen, Chan-Cheng

2008-05-30

Flash point is the most important variable used to characterize fire and explosion hazard of liquids. Herein, partially miscible mixtures are presented within the context of liquid-liquid extraction processes. This paper describes development of a model for predicting the flash point of binary partially miscible mixtures of flammable solvents. To confirm the predictive efficacy of the derived flash points, the model was verified by comparing the predicted values with the experimental data for the studied mixtures: methanol+octane; methanol+decane; acetone+decane; methanol+2,2,4-trimethylpentane; and, ethanol+tetradecane. Our results reveal that immiscibility in the two liquid phases should not be ignored in the prediction of flash point. Overall, the predictive results of this proposed model describe the experimental data well. Based on this evidence, therefore, it appears reasonable to suggest potential application for our model in assessment of fire and explosion hazards, and development of inherently safer designs for chemical processes containing binary partially miscible mixtures of flammable solvents.

Miscible viscous fingering with chemical reaction involving precipitation.

NASA Astrophysics Data System (ADS)

Bae, Si-Kyun; Nagatsu, Yuichiro; Kato, Yoshihito; Tada, Yutaka

2007-11-01

When a reactive and miscible less-viscous liquid displaces a more-viscous liquid in a Hele-Shaw cell, reactive miscible viscous fingering takes place. The present study has experimentally examined how precipitation produced by chemical reaction affects miscible viscous fingering pattern. A 97 wt % glycerin solution containing iron(III) nitrate (yellow) and a solution containing potassium hexacyano ferrate(II) (colorless) were used as the more- and less-viscous liquids, respectively. In this case, the chemical reaction instantaneously takes place and produces the precipitation being dark blue in color. The experiments were done by varying reactant concentrations, the cell's gap width, and the displacement speed. We compared the patterns involving the precipitation reaction with those in the non-reactive cases. We have found fylfot-like pattern is observed, depending on the experimental condition, which has never been formed in the non-reactive experiments. As the reactant concentrations are increased or the displacement speed is decreased, the effects of the precipitation on the patterns are more pronounced.

Characteristic Fracture Spacing in Primary and Secondary Recovery from Naturally Fractured Reservoirs

NASA Astrophysics Data System (ADS)

Gong, J.; Rossen, W.

2015-12-01

We showed previously (Gong and Rossen, 2014a,b) that, if the fracture aperture distribution is broad enough in a naturally fractured reservoir, even one where the fracture network is well-connected, most fractures can be eliminated without significantly affecting the flow through the fracture network. During a waterflood or enhanced-oil-recovery (EOR) process, the production of oil depends on the supply of injected water or EOR agent. This suggests that the characteristic fracture spacing for the dual-porosity/dual-permeability simulation of waterflood or EOR in a naturally fractured reservoir should account not for all fractures but only the relatively small portion of the fracture network carrying almost all the injected water or EOR agent. In contrast, in primary production even a relatively small fracture represents an effective path for oil to flow to a production well. Thus in primary production the effective fracture spacing should include all the fractures. This distinction means that the "shape factor" in dual-porosity/dual-permeability reservoir simulators and the repeating unit in homogenization should depend on the process involved: specifically, it should be different for primary and secondary or tertiary recovery. We test this hypothesis in a simple representation of a fractured reservoir with a non-uniform distribution of fracture flow conductivities. We compare oil production, flow patterns in matrix, and the pattern of oil recovery around fractures with and without the "unimportant" fractures present. In primary production, all fractures which are much more permeable than matrix play a significant role in production. The shape factor or repeating-unit size should reflect the entire fracture distribution. In secondary or tertiary production, the role of fractures that carry relatively little flow depends on injection rate, the ratio of flow carried by the different fractures, and the permeability of matrix. In some cases, the appropriate shape factor or repeating-unit size for waterflood or EOR should reflect only those fractures that carry most of the flow. References:Gong, and Rossen, 14th ECMOR Conf., Catania, Sicily, 2014(a). Gong, and Rossen, Intl. Discrete Fracture Network Eng. Conf., Vancouver, Canada, 2014(b).

SPHEREx: Understanding the Origin and Evolution of Galaxies Through the Extragalactic Background Light

NASA Astrophysics Data System (ADS)

Zemcov, Michael; SPHEREx Science Team

2018-01-01

The near IR extragalactic background light (EBL) encodes the integrated light production over cosmic history, so traces the total emission from all galaxies along the line of sight up to the ancient first-light objects responsible for the epoch of reionization (EOR). The EBL can be constrained through measurements of anisotropies, taking advantage of the fact that extragalactic populations produce fluctuations with distinct spatial and spectral characteristics from local foregrounds. In particular, EBL anisotropies trace the underlying clustering of faint emission sources, such as stars, galaxies and accreting black holes present during the EOR, dwarf galaxies, and intra-halo light (IHL), all of which are components not readily detected in point source surveys. The fluctuation amplitude observed independently by a number of recent measurements exceeds that expected from the large-scale clustering of known galaxy populations, indicating the presence of a large integrated brightness from these faint and diffuse components. Improved large-area measurements covering the entire near-IR are required to constrain the possible models for the history of emission from stars back to the EOR.SPHEREx brings new capabilities to EBL fluctuation measurements, employing 96 spectral channels covering 0.75 to 5 microns with spectral resolving power R = 41 to 135 that enable SPHEREx to carry out a multi-frequency separation of the integrated light from galaxies, IHL, and EOR components using the rich auto- and cross-correlation information available from two 45 square degree surveys of the ecliptic poles. SPHEREx is an ideal intensity mapping machine, and has the sensitivity to disentangle the history of light production associated with EBL fluctuations. SPHEREx will search for an EOR component its to minimum required level through component separation and spectral fitting techniques optimized for the near-IR. In addition to broad-band intensity mapping that enhances and extends the Euclid survey, uniquely SPHEREx will enable tomography of cosmic large scale structure using line tracers such as Lya, Ha, Hb, O[II] and O[III], as highlighted in community workshops and AAS special sessions over the past several years.

Geochemical effects of CO2 injection on produced water chemistry at an enhanced oil recovery site in the Permian Basin of northwest Texas, USA: Preliminary geochemical and Li isotope results

NASA Astrophysics Data System (ADS)

Pfister, S.; Gardiner, J.; Phan, T. T.; Macpherson, G. L.; Diehl, J. R.; Lopano, C. L.; Stewart, B. W.; Capo, R. C.

2014-12-01

Injection of supercritical CO2 for enhanced oil recovery (EOR) presents an opportunity to evaluate the effects of CO2 on reservoir properties and formation waters during geologic carbon sequestration. Produced water from oil wells tapping a carbonate-hosted reservoir at an active EOR site in the Permian Basin of Texas both before and after injection were sampled to evaluate geochemical and isotopic changes associated with water-rock-CO2 interaction. Produced waters from the carbonate reservoir rock are Na-Cl brines with TDS levels of 16.5-34 g/L and detectable H2S. These brines are potentially diluted with shallow groundwater from earlier EOR water flooding. Initial lithium isotope data (δ7Li) from pre-injection produced water in the EOR field fall within the range of Gulf of Mexico Coastal sedimentary basin and Appalachian basin values (Macpherson et al., 2014, Geofluids, doi: 10.1111/gfl.12084). Pre-injection produced water 87Sr/86Sr ratios (0.70788-0.70795) are consistent with mid-late Permian seawater/carbonate. CO2 injection took place in October 2013, and four of the wells sampled in May 2014 showed CO2 breakthrough. Preliminary comparison of pre- and post-injection produced waters indicates no significant changes in the major inorganic constituents following breakthrough, other than a possible drop in K concentration. Trace element and isotope data from pre- and post-breakthrough wells are currently being evaluated and will be presented.

Economic analysis of secondary and enhanced oil recovery techniques in Wyoming

NASA Astrophysics Data System (ADS)

Kara, Erdal

This dissertation primarily aims to theoretically analyze a firm's optimization of enhanced oil recovery (EOR) and carbon dioxide sequestration under different social policies and empirically analyze the firm's optimization of enhanced oil recovery. The final part of the dissertation empirically analyzes how geological factors and water injection management influence oil recovery. The first chapter builds a theoretical model to analyze economic optimization of EOR and geological carbon sequestration under different social policies. Specifically, it analyzes how social policies on sequestration influence the extent of oil operations, optimal oil production and CO2 sequestration. The theoretical results show that the socially optimal policy is a subsidy on the net CO2 sequestration, assuming negative net emissions from EOR. Such a policy is expected to increase a firm's total carbon dioxide sequestration. The second chapter statistically estimates the theoretical oil production model and its different versions. Empirical results are not robust over different estimation techniques and not in line with the theoretical production model. The last part of the second chapter utilizes a simplified version of theoretical model and concludes that EOR via CO2 injection improves oil recovery. The final chapter analyzes how a contemporary oil recovery technology (water flooding of oil reservoirs) and various reservoir-specific geological factors influence oil recovery in Wyoming. The results show that there is a positive concave relationship between cumulative water injection and cumulative oil recovery and also show that certain geological factors affect the oil recovery. Moreover, the curvature of the concave functional relationship between cumulative water injection and oil recovery is reservoir-specific due to heterogeneities among different reservoirs.

Dynamic stabilization of the Rayleigh-Taylor instability of miscible liquids and the related "frozen waves"

NASA Astrophysics Data System (ADS)

Wolf, Gerd Gerhard H.

2018-02-01

Superimposed miscible liquids, the heavier one on top, when subjected to vibrations vertical to their interface (dynamic stabilization), can only be maintained for a certain period. A mechanism is presented explaining the resulting process of degradation and "anomalous diffusion" through that interface. Superimposed liquids, the lighter one on top, exposed to horizontal vibrations, develop a saw-tooth-like pattern called "frozen waves." These are subject to conditions similar to those of dynamic stabilization and, if miscible, thus can also only be maintained for a certain period. A further analysis of these processes would be desirable, also in view of their relation to analogue phenomena.

MISCIBILITY, SOLUBILITY, VISCOSITY, AND DENSITY MEASUREMENTS FOR R-236EA WITH FOUR DIFFERENT EXXON LUBRICANTS

EPA Science Inventory

The report discusses miscibility, solubility, viscosity, and density data for the refrigerant hydrofluorocarbon (HFC)-236ea (or R-236ea) and four lubricants supplied by Exxon Corporation. Such data are needed to determine the suitability of refrigerant/lubricant combinations for ...

The first data on the porous space structure of the Domanik shales as a potential object for EOR applying

NASA Astrophysics Data System (ADS)

Kadyrov, R.; Statsenko, E.

2018-05-01

The resources of shale oil, contained in the organic matter of the wood deposits, can be considered as a source of profitable production of hydrocarbons, when modern EOR technologies are used. As a result of the primary studies of the pore space structure, it is revealed that two types of porous space are prevailing in the studied samples of the Domanik oil shales. The most prevailing is intrakerogen porosity with pore volumes of 5 × 10-8 1 × 10-6 mm3. The volumetric reconstruction of the structure of this pore space shows that the voids are confined directly to micro lenses of organic matter. The second type of the found void is represented by leaching cracks. It is characteristic of more carbonate varieties of the Dominik oil shale with spotted structure. It is the oil shale intervals with such cracks that are of greatest interest to the EOR, since they consist of a large area with smaller pores and through which pressurization and spread of various agents are possible to occur in order to increase the oil recovery.

Exploring a Massive Starburst in the Epoch of Reionization

NASA Astrophysics Data System (ADS)

Marrone, Daniel; Aravena, M.; Chapman, S.; De Breuck, C.; Gonzalez, A.; Hezavehe, S.; Litke, K.; Ma, J.; Malkan, M.; Spilker, J.; Stalder, B.; Stark, D.; Strandet, M.; Tang, M.; Vieira, J.; Weiss, A.; Welikala, N.

2016-08-01

We request deep multi-band imaging of a unique dusty galaxy in the Epoch of Reionization (EoR), selected via its millimeter-wavelength dust emission in the 2500-square-degree South Pole Telescope survey. Spectroscopically confirmed to lie at z=6.900, this galaxy has a large dust mass and is likely one of the most rapidly star-forming objects in the EoR. Using Gemini-S, we have identified z-band emission from this object that could be UV continuum emission at z=6.9 or from a foreground lens. Interpretation of this object, and a complete understanding of its meaning for the census of star formation in the EoR, requires that we establish the presence or absence of gravitational lensing. The dust mass observed in this source is also unexpectedly large for its era, and measurements of the assembled stellar population, through the UV-continuum slope and restframe optical color, will help characterize the stellar mass and dust properties in this very early galaxy, the most spectacular galaxy yet discovered by the SPT.

Line Intensity Mapping during the Epoch of Reionization

NASA Astrophysics Data System (ADS)

Silva, Marta B.; Zaroubi, Saleem

2018-05-01

Characterizing the properties and the evolution of the first stars and galaxies is a challenging task for traditional galaxy surveys since they are sensitivity limited and can only detect the brightest light sources. Three-dimensional intensity mapping (IM) of transition lines can be a valuable alternative to study the high redshift Universe given that this technique avoids sensitivity limitation problems by measuring the overall emission of a line, with a low resolution, without resolving its sources. While 21cm line IM surveys probe neutral hydrogen gas and can, therefore, be used to probe the state of the IGM and the evolution of the ionization field during the Epoch of Reionization (EoR). IM surveys of other lines, such as CO, CII, Ly-alpha or H-alpha, can be used to probe the galaxies which emitted most of the ionizing radiation responsible for the EoR. These lines will trace the different ISM gas phases, the excitation state of this gas, its metallicity, etc. This study addresses IM of multiple transition lines and how it can be used to probe the EoR and to constrain the redshift evolution of galaxy properties.

Nonergodicity in binary alloys

NASA Astrophysics Data System (ADS)

Son, Leonid; Sidorov, Valery; Popel, Pjotr; Shulgin, Dmitry

2015-09-01

For binary liquids with limited miscibility of the components, we provide the corrections to the equation of state which arise from the nonergogic diffusivity. It is shown that these corrections result in lowering of critical miscibility point. In some cases, it may result in a bifurcation of miscibility curve: the mixtures near 50% concentration which are homogeneous at the microscopic level, occur to be too stable to provide a quasi - eutectic triple point. These features provide a new look on the phase diagrams of some binary systems. In present work, we discuss Ga-Pb, Fe-Cu, and Cu-Zr alloys. Our investigation corresponds their complex behavior in liquid state to the shapes of their phase diagrams.

Displacement front behavior of near miscible CO2 flooding in decane saturated synthetic sandstone cores revealed by magnetic resonance imaging.

PubMed

Liu, Yu; Teng, Ying; Jiang, Lanlan; Zhao, Jiafei; Zhang, Yi; Wang, Dayong; Song, Yongchen

2017-04-01

It is of great importance to study the CO 2 -oil two-phase flow characteristic and displacement front behavior in porous media, for understanding the mechanisms of CO 2 enhanced oil recovery. In this work, we carried out near miscible CO 2 flooding experiments in decane saturated synthetic sandstone cores to investigate the displacement front characteristic by using magnetic resonance imaging technique. Experiments were done in three consolidated sandstone cores with the permeabilities ranging from 80 to 450mD. The oil saturation maps and the overall oil saturation during CO 2 injections were obtained from the intensity of magnetic resonance imaging. Finally the parameters of the piston-like displacement fronts, including the front velocity and the front geometry factor (the length to width ratio) were analyzed. Experimental results showed that the near miscible vertical upward displacement is instable above the minimum miscible pressure in the synthetic sandstone cores. However, low permeability can restrain the instability to some extent. Copyright © 2016 Elsevier Inc. All rights reserved.

Fabrication of thermoplastic ductile films of chitin butyrate/poly(ɛ-caprolactone) blends and their cytocompatibility.

PubMed

Hashiwaki, Hiroki; Teramoto, Yoshikuni; Nishio, Yoshiyuki

2014-12-19

We fabricate thermoplastic films of chitin burtyrate (ChB)/poly(ɛ-caprolactone) (PCL) blends with different degree of miscibility (miscible (M), partially miscible (PM), and immiscible (IM)), and examined the feasibility as a cell scaffold system through evaluating mechanical properties and cytocompatibility. We found a remediation of the brittleness and an increase in ductility of ChB by blending PCL for the M and PM blends. The blend films were subjected to alkaline hydrolysis (2-M NaOH/37°C/48 h) with expectation of the improvement of the surface hydrophilicity and cell accessibility. ATR-FTIR spectroscopy of the alkaline-treated PM and IM films revealed that PCL component and ester side-chains of acyl chitin were selectively removed from the surface domain. L929 fibroblast cells well adhered and proliferated on these films. Therefore, the materials possess a great potential for the utilization as a thermoplastic cell scaffold in tissue engineering by adequate selection of the degree of miscibility and post treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

Preparation and Analysis of Co-precipitated, Biodegradable Poly-(Lactide-co-Glycolide) and Polyethylene Glycol Microspheres Prepared by Spray Drying

NASA Astrophysics Data System (ADS)

Javiya, Curie

Biodegradable poly-(d,l-lactide-co-glycolide) (PLGA) based microspheres are commonly used for numerous clinical applications. PEG is a widely used polymer due to its hydrophilic, biocompatible, and nontoxic nature. In this study, different blends of PLGA/PEG microspheres were prepared using a spray drying technique. The microspheres were spherical with maximum yield found to be 60.3% and average particle size in the range of 2.4 to 3.1 microm. Under the spray drying processing conditions, the polymers showed full miscibility slightly below 15% w/w and partial miscibility up to 20% w/w of PEG in the blended microspheres. At higher temperatures, PLGA and PEG were miscible in all proportions used for the blended microspheres. Blending 10% w/w PEG in PLGA membranes showed significant reduction in attachment of macrophages compared to PLGA membranes. The in-vitro response of macrophage towards the miscible blends of PLGA/PEG microspheres was further characterized. Results showed some reduction in macrophage viability and activation, however, significant effects with PLGA/PEG microspheres were not observed.

Miscibility Studies on Polymer Blends Modified with Phytochemicals

NASA Astrophysics Data System (ADS)

Chandrasekaran, Neelakandan; Kyu, Thein

2009-03-01

The miscibility studies related to an amorphous poly(amide)/poly(vinyl pyrrolidone) [PA/PVP] blend with a crystalline phytochemical called ``Mangiferin'' is presented. Phytochemicals are plant derived chemicals which intrinsically possess multiple salubrious properties that are associated with prevention of diseases such as cancer, diabetes, cardiovascular disease, and hypertension. Incorporation of phytochemicals into polymers has shown to have very promising applications in wound healing, drug delivery, etc. The morphology of these materials is crucial to applications like hemodialysis, which is governed by thermodynamics and kinetics of the phase separation process. Hence, miscibility studies of PA/PVP blends with and without mangiferin have been carried out using dimethyl sulfoxide as a common solvent. Differential scanning calorimetry studies revealed that the binary PA/PVP blends were completely miscible at all compositions. However, the addition of mangiferin has led to liquid-liquid phase separation and liquid-solid phase transition in a composition dependent manner. Fourier transformed infrared spectroscopy was undertaken to determine specific interaction between the polymer constituents and the role of possible hydrogen bonding among three constituents will be discussed.

Maté drinking and esophageal squamous cell carcinoma in South America: pooled results from two large multicenter case-control studies.

PubMed

Lubin, Jay H; De Stefani, Eduardo; Abnet, Christian C; Acosta, Gisele; Boffetta, Paolo; Victora, Cesar; Graubard, Barry I; Muñoz, Nubia; Deneo-Pellegrini, Hugo; Franceschi, Silvia; Castellsagué, Xavier; Ronco, Alvaro L; Dawsey, Sanford M

2014-01-01

Maté tea is a nonalcoholic infusion widely consumed in southern South America, and may increase risk of esophageal squamous cell carcinoma (ESCC) and other cancers due to polycyclic aromatic hydrocarbons (PAH) and/or thermal injury. We pooled two case-control studies: a 1988 to 2005 Uruguay study and a 1986 to 1992 multinational study in Argentina, Brazil, Paraguay, and Uruguay, including 1,400 cases and 3,229 controls. We computed ORs and fitted a linear excess OR (EOR) model for cumulative maté consumption in liters/day-year (LPDY). The adjusted OR for ESCC with 95% confidence interval (CI) by ever compared with never use of maté was 1.60 (1.2-2.2). ORs increased linearly with LPDY (test of nonlinearity; P = 0.69). The estimate of slope (EOR/LPDY) was 0.009 (0.005-0.014) and did not vary with daily intake, indicating maté intensity did not influence the strength of association. EOR/LPDY estimates for consumption at warm, hot, and very hot beverage temperatures were 0.004 (-0.002-0.013), 0.007 (0.003-0.013), and 0.016 (0.009-0.027), respectively, and differed significantly (P < 0.01). EOR/LPDY estimates were increased in younger (<65) individuals and never alcohol drinkers, but these evaluations were post hoc, and were homogeneous by sex. ORs for ESCC increased linearly with cumulative maté consumption and were unrelated to intensity, so greater daily consumption for shorter duration or lesser daily consumption for longer duration resulted in comparable ORs. The strength of association increased with higher maté temperatures. Increased understanding of cancer risks with maté consumption enhances the understanding of the public health consequences given its purported health benefits.

The hydrogen epoch of reionization array dish III: measuring chromaticity of prototype element with reflectometry

NASA Astrophysics Data System (ADS)

Patra, Nipanjana; Parsons, Aaron R.; DeBoer, David R.; Thyagarajan, Nithyanandan; Ewall-Wice, Aaron; Hsyu, Gilbert; Leung, Tsz Kuk; Day, Cherie K.; de Lera Acedo, Eloy; Aguirre, James E.; Alexander, Paul; Ali, Zaki S.; Beardsley, Adam P.; Bowman, Judd D.; Bradley, Richard F.; Carilli, Chris L.; Cheng, Carina; Dillon, Joshua S.; Fadana, Gcobisa; Fagnoni, Nicolas; Fritz, Randall; Furlanetto, Steve R.; Glendenning, Brian; Greig, Bradley; Grobbelaar, Jasper; Hazelton, Bryna J.; Jacobs, Daniel C.; Julius, Austin; Kariseb, MacCalvin; Kohn, Saul A.; Lebedeva, Anna; Lekalake, Telalo; Liu, Adrian; Loots, Anita; MacMahon, David; Malan, Lourence; Malgas, Cresshim; Maree, Matthys; Martinot, Zachary; Mathison, Nathan; Matsetela, Eunice; Mesinger, Andrei; Morales, Miguel F.; Neben, Abraham R.; Pieterse, Samantha; Pober, Jonathan C.; Razavi-Ghods, Nima; Ringuette, Jon; Robnett, James; Rosie, Kathryn; Sell, Raddwine; Smith, Craig; Syce, Angelo; Tegmark, Max; Williams, Peter K. G.; Zheng, Haoxuan

2018-04-01

Spectral structures due to the instrument response is the current limiting factor for the experiments attempting to detect the redshifted 21 cm signal from the Epoch of Reionization (EoR). Recent advances in the delay spectrum methodology for measuring the redshifted 21 cm EoR power spectrum brought new attention to the impact of an antenna's frequency response on the viability of making this challenging measurement. The delay spectrum methodology provides a somewhat straightforward relationship between the time-domain response of an instrument that can be directly measured and the power spectrum modes accessible to a 21 cm EoR experiment. In this paper, we derive the explicit relationship between antenna reflection coefficient ( S 11) measurements made by a Vector Network Analyzer (VNA) and the extent of additional foreground contaminations in delay space. In the light of this mathematical framework, we examine the chromaticity of a prototype antenna element that will constitute the Hydrogen Epoch of Reionization Array (HERA) between 100 and 200 MHz. These reflectometry measurements exhibit additional structures relative to electromagnetic simulations, but we find that even without any further design improvement, such an antenna element will support measuring spatial k modes with line-of-sight components of k ∥ > 0.2 h Mpc- 1. We also find that when combined with the powerful inverse covariance weighting method used in optimal quadratic estimation of redshifted 21 cm power spectra the HERA prototype elements can successfully measure the power spectrum at spatial modes as low as k ∥ > 0.1 h Mpc- 1. This work represents a major step toward understanding the HERA antenna element and highlights a straightforward method for characterizing instrument response for future experiments designed to detect the 21 cm EoR power spectrum.

Mechanism of C-C and C-H bond cleavage in ethanol oxidation reaction on Cu2O(111): a DFT-D and DFT+U study.

PubMed

Xu, Han; Miao, Bei; Zhang, Minhua; Chen, Yifei; Wang, Lichang

2017-10-04

The performance of transition metal catalysts for ethanol oxidation reaction (EOR) in direct ethanol fuel cells (DEFCs) may be greatly affected by their oxidation. However, the specific effect and catalytic mechanism for EOR of transition metal oxides are still unclear and deserve in-depth exploitation. Copper as a potential anode catalyst can be easily oxidized in air. Thus, in this study, we investigated C-C and C-H bond cleavage reactions of CH x CO (x = 1, 2, 3) species in EOR on Cu 2 O(111) using PBE+U calculations, as well as the specific effect of +U correction on the process of adsorption and reaction on Cu 2 O(111). It was revealed that the catalytic performance of Cu 2 O(111) for EOR was restrained compared with that of Cu(100). Except for the C-H cleavage of CH 2 CO, all the reaction barriers for C-C and C-H cleavage were higher than those on Cu(100). The most probable pathway for CH 3 CO to CHCO on Cu 2 O(111) was the continuous dehydrogenation reaction. Besides, the barrier for C-C bond cleavage increased due to the loss of H atoms in the intermediate. Moreover, by the comparison of the traditional GGA/PBE method and the PBE+U method, it could be concluded that C-C cleavage barriers would be underestimated without +U correction, while C-H cleavage barriers would be overestimated. +U correction was proved to be necessary, and the reaction barriers and the values of the Hubbard U parameter had a proper linear relationship.

Preliminary Public Design Report for the Texas Clean Energy Project: Topical Report - Phase 1, June 2010-July 2011

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mattes, Karl

Summit Texas Clean Energy, LLC (Summit) is developing the Texas Clean Energy Project (TCEP or the project) to be located near Penwell, Texas. The TCEP will include an Integrated Gasification Combined Cycle (IGCC) plant with a nameplate capacity of 400 megawatts electric (MWe), combined with the production of urea fertilizer and the capture, utilization and storage of carbon dioxide (CO 2) sold commercially for regional use in enhanced oil recovery (EOR) in the Permian Basin of west Texas. The TCEP will utilize coal gasification technology to convert Powder River Basin sub-bituminous coal delivered by rail from Wyoming into a syntheticmore » gas (syngas) which will be cleaned and further treated so that at least 90 percent of the overall carbon entering the facility will be captured. The clean syngas will then be divided into two high-hydrogen (H 2) concentration streams, one of which will be combusted as a fuel in a combined cycle power block for power generation and the other converted into urea fertilizer for commercial sale. The captured CO 2 will be divided into two streams: one will be used in producing the urea fertilizer and the other will be compressed for transport by pipeline for offsite use in EOR. The TCEP was selected by the U.S. Department of Energy (DOE) Office of Fossil Energy (FE) for cost-shared co-funded financial assistance under Round 3 of its Clean Coal Power Initiative (CCPI). A portion of this financial assistance was budgeted and provided for initial development, permitting and design activities. Front-end Engineering and Design (FEED) commenced in June 2010 and was completed in July 2011, setting the design basis for entering into the detailed engineering phase of the project. During Phase 1, TCEP conducted and completed the FEED, applied for and received its air construction permit, provided engineering and other technical information required for development of the draft Environmental Impact Statement, and completed contracts for the sale of all of the urea and most of the CO 2. Significant progress was made on the contracts for the purchase of coal feedstock from Cloud Peak Energy’s Cordero Rojo mine and the sale of electricity to CPS Energy, as well as a memorandum of understanding with the Union Pacific Railroad (UPRR) for delivery of the coal to the TCEP site.« less

Melt Miscibility in Block Copolymers Containing Polyethylene and Substituted Polynorbornenes

NASA Astrophysics Data System (ADS)

Mulhearn, William; Register, Richard

Very few polymer species exist with a sufficiently weak repulsive interaction against polyethylene (PE), characterized by a low Flory parameter χ or interaction energy density X, to be useful for preparing PE-containing block copolymers with disordered melts at high molecular weights. Most suitably miscible polymers are chemically similar to PE, such as copolymers of ethylene with a minority content of an α-olefin, and so are only marginally useful for property modification due to similar physical properties like the glass transition temperature (Tg) . However, the family of polymers consisting of substituted norbornenes prepared via ring-opening metathesis polymerization (ROMP) and subsequent hydrogenation is unique in that many of its members exhibit very low X against PE (comparable with the interaction energy between poly(ethylene-alt-propylene) and PE), and some of these also exhibit high Tg. The miscibility between PE and a substituted, hydrogenated ROMP polynobornene, or between two dissimilar hydrogenated polynorbornenes, is a strong function of the substituent appended to the norbornene monomer. The mixing thermodynamics of this polymer series are irregular, in that the interaction energies do not follow X = (δ1 - δ2)2 where δ is the solubility parameter. However, other systematic trends do apply and we develop a set of mixing rules to quantitatively describe the experimental miscibility behavior. We also investigate statistical copolymerization of two norbornene monomers as a means to continuously tune miscibility with a homopolymer of a third monomer.

Miscibility and in vitro osteocompatibility of biodegradable blends of poly[(ethyl alanato) (p-phenyl phenoxy) phosphazene] and poly(lactic acid-glycolic acid).

PubMed

Deng, Meng; Nair, Lakshmi S; Nukavarapu, Syam P; Kumbar, Sangamesh G; Jiang, Tao; Krogman, Nicholas R; Singh, Anurima; Allcock, Harry R; Laurencin, Cato T

2008-01-01

Previously we demonstrated the ability of ethyl glycinato substituted polyphosphazenes to neutralize the acidic degradation products and control the degradation rate of poly(lactic acid-glycolic acid) (PLAGA) by blending. In this study, blends of high strength poly[(50% ethyl alanato) (50% p-phenyl phenoxy) phosphazene] (PNEA(50)PhPh(50)) and 85:15 PLAGA were prepared using a mutual solvent approach. Three different solvents, methylene chloride (MC), chloroform (CF) and tetrahydrofuran (THF) were studied to investigate solvent effects on blend miscibility. Three different blends were then fabricated at various weight ratios namely 25:75 (BLEND25), 50:50 (BLEND50), and 75:25 (BLEND75) using THF as the mutual solvent. The miscibility of the blends was evaluated by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR). Among these, BLEND25 was miscible while BLEND50 and BLEND75 were partially miscible. Furthermore, BLEND25 formed apatite layers on its surface as evidenced in a biomimetic study performed. These novel blends showed cell adhesion and proliferation comparable to PLAGA. However, the PNEA(50)PhPh(50) component in the blends was able to increase the phenotypic expression and mineralized matrix synthesis of the primary rat osteoblasts (PRO) in vitro. Blends of high strength PNEA(50)PhPh(50) and 85:15 PLAGA are promising biomaterials for a variety of musculoskeletal applications.

Magnetic resonance imaging study on near miscible supercritical CO2 flooding in porous media

NASA Astrophysics Data System (ADS)

Song, Yongchen; Zhu, Ningjun; Zhao, Yuechao; Liu, Yu; Jiang, Lanlan; Wang, Tonglei

2013-05-01

CO2 flooding is one of the most popular secondary or tertiary recoveries for oil production. It is also significant for studying the mechanisms of the two-phase and multiphase flow in porous media. In this study, an experimental study was carried out by using magnetic resonance imaging technique to examine the detailed effects of pressure and rates on CO2/decane flow in a bead-pack porous media. The displacing processes were conducted under various pressures in a region near the minimum miscibility pressure (the system tuned from immiscible to miscible as pressure is increasing in this region) and the temperature of 37.8 °C at several CO2 injection volumetric rates of 0.05, 0.10, and 0.15 ml/min (or linear rates of 3.77, 7.54, and 11.3 ft/day). The evolution of the distribution of decane and the characteristics of the two phase flow were investigated and analyzed by considering the pressure and rate. The area and velocity of the transition zone between the two phases were calculated and analyzed to quantify mixing. The area of transition zone decreased with pressure at near miscible region and a certain injection rate and the velocity of the transition zone was always less than the "volumetric velocity" due to mutual solution and diffusion of the two phases. Therefore, these experimental results give the fundamental understanding of tertiary recovery processes at near miscible condition.

The Dynamics of Miscible Interfaces: Simulations

NASA Technical Reports Server (NTRS)

Meiburg, Eckart

2002-01-01

The goal of this experimental/computational investigation (joint with Prof Maxworthy at USC) has been to study the dynamics of miscible interfaces, both from a scientific and a practical point of view, and to prepare a related experiment to be flown on the International Space Station. In order to address these effects, we have focused experimental and computational investigations on miscible displacements in cylindrical capillary tubes, as well as in Hele-Shaw cells. Regarding the flow in a capillary tube, the question was addressed as to whether Korteweg stresses and/or divergence effects can potentially account for discrepancies observed between conventional Stokes flow simulations and experiments for miscible flows in capillary tubes. An estimate of the vorticity and streamfunction fields induced by the Kortewegs stresses was derived, which shows these stresses to result in the formation of a vortex ring structure near the tip of the concentration front. Through this mechanism the propagation velocity of the concentration front is reduced, in agreement with the experimental observations. Divergence effects, on the other hand, were seen to be very small, and they have a negligible influence on the tip velocity. As a result, it can be concluded that they are not responsible for the discrepancies between experiments and conventional Stokes simulations. A further part of our investigation focussed on the development of high-accuracy three-dimensional spectral element simulation techniques for miscible flows in capillary tubes, including the effects of variable density and viscosity. Towards this end, the conservation equations are treated in cylindrical coordinates.

Three dimensional graphene foam supported platinum-ruthenium bimetallic nanocatalysts for direct methanol and direct ethanol fuel cell applications

NASA Astrophysics Data System (ADS)

Kung, Chih-Chien; Lin, Po-Yuan; Xue, Yuhua; Akolkar, Rohan; Dai, Liming; Yu, Xiong; Liu, Chung-Chiun

2014-06-01

A novel composite material of hierarchically structured platinum-ruthenium (PtRu) nanoparticles grown on large surface area three dimensional graphene foam (3D GF) is reported. 3D GF was incorporated with PtRu bimetallic nanoparticles as an electrochemical nanocatalyst for methanol and ethanol oxidation. PtRu/3D GF nanocatalyst showed a higher tolerance to poisoning by CO and exhibited improved catalytic activity for both methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR). Cyclic voltammetry (CV) results and long-term cycling stability tests demonstrated that GF provided a promising platform for the development of electrochemical nanocatalysts. Specifically, PtRu/3D GF nanocatalyst showed excellent catalytic activity toward MOR and EOR compared with PtRu/Graphene (Commercial graphene), PtRu/C (Vulcan XC-72R carbon), and PtRu alone. The crystal size of PtRu on 3D GF was reduced to 3.5 nm and its active surface area was enhanced to 186.2 m2 g-1. Consequently, the MOR and EOR rates were nearly doubled on PtRu/3D GF compared to those on PtRu/Graphene.

Integrated Geophysical Monitoring Program to Study Flood Performance and Incidental CO2 Storage Associated with a CO2 EOR Project in the Bell Creek Oil Field

NASA Astrophysics Data System (ADS)

Burnison, S. A.; Ditty, P.; Gorecki, C. D.; Hamling, J. A.; Steadman, E. N.; Harju, J. A.

2013-12-01

The Plains CO2 Reduction (PCOR) Partnership, led by the Energy & Environmental Research Center, is working with Denbury Onshore LLC to determine the effect of a large-scale injection of carbon dioxide (CO2) into a deep clastic reservoir for the purpose of simultaneous CO2 enhanced oil recovery (EOR) and to study incidental CO2 storage at the Bell Creek oil field located in southeastern Montana. This project will reduce CO2 emissions by more than 1 million tons a year while simultaneously recovering an anticipated 30 million barrels of incremental oil. The Bell Creek project provides a unique opportunity to use and evaluate a comprehensive suite of technologies for monitoring, verification, and accounting (MVA) of CO2 on a large-scale. The plan incorporates multiple geophysical technologies in the presence of complementary and sometimes overlapping data to create a comprehensive data set that will facilitate evaluation and comparison. The MVA plan has been divided into shallow and deep subsurface monitoring. The deep subsurface monitoring plan includes 4-D surface seismic, time-lapse 3-D vertical seismic profile (VSP) surveys incorporating a permanent borehole array, and baseline and subsequent carbon-oxygen logging and other well-based measurements. The goal is to track the movement of CO2 in the reservoir, evaluate the recovery/storage efficiency of the CO2 EOR program, identify fluid migration pathways, and determine the ultimate fate of injected CO2. CO2 injection at Bell Creek began in late May 2013. Prior to injection, a monitoring and characterization well near the field center was drilled and outfitted with a distributed temperature-monitoring system and three down-hole pressure gauges to provide continuous real-time data of the reservoir and overlying strata. The monitoring well allows on-demand access for time-lapse well-based measurements and borehole seismic instrumentation. A 50-level permanent borehole array of 3-component geophones was installed in a second monitoring well. A pre-injection series of carbon-oxygen logging across the reservoir was acquired in 35 wells. The baseline 3-D surface seismic survey was acquired in September 2012. A 3-D VSP incorporating two wells and 2 square miles of overlapping seismic coverage in the middle of the field was acquired in May 2013. Initial iterations of geologic modeling and reservoir simulation of the field have been completed. Currently, passive seismic monitoring with the permanent borehole array is being conducted during injection. Interpretation results from the baseline surface 3-D survey and preliminary results from the baseline 3-D VSP are being evaluated and integrated into the reservoir model. The PCOR Partnership's philosophy is to combine site characterization, modeling, and monitoring strategies into an iterative process to produce descriptive integrated results. The comprehensive effort at Bell Creek will allow a comparison of the effectiveness of several complementary geophysical and well-based methods in meeting the goals of the deep subsurface monitoring effort.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burnison, Shaughn; Livers-Douglas, Amanda; Barajas-Olalde, Cesar

The scalable, automated, semipermanent seismic array (SASSA) project led and managed by the Energy & Environmental Research Center (EERC) was designed as a 3-year proof-of-concept study to evaluate and demonstrate an innovative application of the seismic method. The concept was to use a sparse surface array of 96 nodal seismic sensors paired with a single, remotely operated active seismic source at a fixed location to monitor for CO 2 saturation changes in a subsurface reservoir by processing the data for time-lapse changes at individual, strategically chosen reservoir reflection points. The combination of autonomous equipment and modern processing algorithms was usedmore » to apply the seismic method in a manner different from the normal paradigm of collecting a spatially dense data set to produce an image. It was used instead to monitor individual, strategically chosen reservoir reflection points for detectable signal character changes that could be attributed to the passing of a CO 2 saturation front or, possibly, changes in reservoir pressure. Data collection occurred over the course of 1 year at an oil field undergoing CO 2 injection for enhanced oil recovery (EOR) and focused on four overlapping “five-spot” EOR injector–producer patterns. Selection, procurement, configuration, installation, and testing of project equipment and collection of five baseline data sets were completed in advance of CO 2 injection within the study area. Weekly remote data collection produced 41 incremental time-lapse records for each of the 96 nodes. Validation was provided by two methods: 1) a conventional 2-D seismic line acquired through the center of the study area before injection started and again after the project ended and processed in a time-lapse manner and 2) by CO 2 saturation maps created from reservoir simulations based on injection and production history matching. Interpreted results were encouraging but mixed, with indications of changes likely due to the presence of CO 2 on some node reflection points where and when effects would be expected and noneffects where no CO 2 was expected, while results at some locations where simulation outputs suggested CO 2 should be present were ambiguous. Acquisition noise impacted interpretation of data at several locations. Many lessons learned were generated by the study to inform and improve results on a follow-up study. The ultimate aim of the project was to evaluate whether deployment of a SASSA technology can provide a useful and cost-effective monitoring solution for future CO 2 injection projects. The answer appears to be affirmative, with the expectation that lessons learned applied to future iterations, together with technology advances, will likely result in significant improvements.« less

Miscibility and in vitro osteocompatibility of biodegradable blends of poly[(ethyl alanato) (p-phenyl phenoxy) phosphazene] and poly(lactic acid-glycolic acid)

PubMed Central

Deng, Meng; Nair, Lakshmi S.; Nukavarapu, Syam P.; Kumbar, Sangamesh G.; Jiang, Tao; Krogman, Nicholas R.; Singh, Anurima; Allcock, Harry R.; Laurencin, Cato T.

2007-01-01

Previously we demonstrated the ability of ethyl glycinato substituted polyphosphazenes to neutralize the acidic degradation products and control the degradation rate of poly(lactic acid-glycolic acid) by blending. In this study, blends of high strength poly[(50% ethyl alanato) (50% p-phenyl phenoxy) phosphazene] (PNEA50PhPh50) and 85:15 poly(lactic acid-glycolic acid) (PLAGA) were prepared using a mutual solvent approach. Three different solvents, methylene chloride (MC), chloroform (CF) and tetrahydrofuran (THF) were studied to investigate solvent effects on blend miscibility. Three different blends were then fabricated at various weight ratios namely 25:75 (BLEND25), 50:50 (BLEND50), and 75:25 (BLEND75) using THF as the mutual solvent. The miscibility of the blends was evaluated by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR). Among these, BLEND25 was miscible while BLEND50 and BLEND75 were partially miscible. Furthermore, BLEND25 formed apatite layers on its surface as evidenced in a biomimetic study performed. These novel blends showed cell adhesion and proliferation comparable to PLAGA. However, the PNEA50PhPh50 component in the blends was able to increase the phenotypic expression and mineralized matrix synthesis of the primary rat osteoblasts (PRO) in vitro. Blends of high strength poly[(50% ethyl alanato) (50% p-phenyl phenoxy) phosphazene] (PNEA50PhPh50) and 85:15 poly(lactic acid-glycolic acid) (PLAGA) are promising biomaterials for a variety of musculoskeletal applications. PMID:17942150

Estimation of minimum miscibility pressure (MMP) of CO2 and liquid n-alkane systems using an improved MRI technique.

PubMed

Liu, Yu; Jiang, Lanlan; Song, Yongchen; Zhao, Yuechao; Zhang, Yi; Wang, Dayong

2016-02-01

Minimum miscible pressure (MMP) of gas and oil system is a key parameter for the injection system design of CO2 miscible flooding. Some industrial standard approaches such as the experiment using a rising bubble apparatus (RBA), the slim tube tests (STT), the pressure-density diagram (PDD), etc. have been applied for decades to determine the MMP of gas and oil. Some theoretical or experiential calculations of the MMP were also applied to the gas-oil miscible system. In the present work, an improved technique based on our previous research for the estimation of the MMP by using magnetic resonance imaging (MRI) was proposed. This technique was then applied to the CO2 and n-alkane binary and ternary systems to observe the mixing procedure and to study the miscibility. MRI signal intensities, which represent the proton concentration of n-alkane in both the hydrocarbon rich phase and the CO2 rich phase, were plotted as a reference for determining the MMP. The accuracy of the MMP obtained by using this improved technique was enhanced comparing with the data obtained from our previous works. The results also show good agreement with other established techniques (such as the STT) in previous published works. It demonstrates increases of MMPs as the temperature rise from 20 °C to 37.8 °C. The MMPs of CO2 and n-alkane systems are also found to be proportional to the carbon number in the range of C10 to C14. Copyright © 2015 Elsevier Inc. All rights reserved.

CarbonSAFE Illinois - Macon County

DOE Office of Scientific and Technical Information (OSTI.GOV)

Whittaker, Steve

CarbonSAFE Illinois is a a Feasibility study to develop an established geologic storage complex in Macon County, Illinois, for commercial-scale storage of industrially sourced CO2. Feasibility activities are focused on the Mt. Simon Storage Complex; a step-out well will be drilled near existing storage sites (i.e., the Midwest Geological Sequestration Consortium’s Illinois Basin – Decatur Project and the Illinois Industrial Carbon Capture and Storage Project) to further establish commercial viability of this complex and to evaluate EOR potential in a co-located oil-field trend. The Archer Daniels Midland facility (ethanol plant), City Water, Light, and Power in Springfield, Illinois (coal-fired powermore » station), and other regional industries are potential sources of anthropogenic CO2 for storage at this complex. Site feasibility will be evaluated through drilling results, static and dynamic modeling, and quantitative risk assessment. Both studies will entail stakeholder engagement, consideration of infrastructure requirements, existing policy, and business models. Project data will help calibrate the National Risk Assessment Partnership (NRAP) Toolkit to better understand the risks of commercial-scale carbon storage.« less

Miscibility of poly(lactic acid) and poly(ethylene oxide) solvent polymer blends and nanofibers made by solution blow spinning

USDA-ARS?s Scientific Manuscript database

The miscibility of blends of poly(lactic acid) (PLA) and poly(ethylene oxide) (PEO) was studied in polymer solutions by dilute solution viscometry and in solution blow spun nanofibers by microscopy (SEM, TEM) and by thermal and spectral analysis. Three blends of PLA and PEO were solution blended in...

A smoothed particle hydrodynamics model for miscible flow in three-dimensional fractures and the two-dimensional Rayleigh–Taylor instability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tartakovsky, Alexandre M.; Meakin, Paul

2005-08-10

A numerical model based on smoothed particle hydrodynamics (SPH) has been developed and used to simulate the classical two-dimensional Rayleigh–Taylor instability and three-dimensional miscible flow in fracture apertures with complex geometries. To model miscible flow fluid particles with variable, composition dependent, masses were used. By basing the SPH equations on the particle number density artificial surface tension effects were avoided. The simulation results for the growth of a single perturbation driven by the Rayleigh – Taylor instability compare well with numerical results obtained by Fournier et al., and the growth of a perturbation with time can be represented quite wellmore » by a second-degree polynomial, in accord with the linear stability analysis of Duff et al. The dispersion coefficient found from SPH simulation of flow and diffusion in an ideal fracture was in excellent agreement with the value predicted by the theory of Taylor and Aris. The simulations of miscible flow in fracture apertures can be used to determination dispersion coefficients for transport in fractured media - a parameter used in large-scale simulations of contaminant transport.« less

The Galactic interstellar medium: foregrounds and star formation

NASA Astrophysics Data System (ADS)

Miville-Deschênes, Marc-Antoine

2018-05-01

This review presents briefly two aspects of Galactic interstellar medium science that seem relevant for studying EoR. First, we give some statistical properties of the Galactic foreground emission in the diffuse regions of the sky. The properties of the emission observed in projection on the plane of the sky are then related to how matter is organised along the line of sight. The diffuse atomic gas is multi-phase, with dense filamentary structures occupying only about 1% of the volume but contributing to about 50% of the emission. The second part of the review presents aspect of structure formation in the Galactic interstellar medium that could be relevant for the subgrid physics used to model the formation of the first stars.

Molecular design of high performance zwitterionic liquids for enhanced heavy-oil recovery processes.

PubMed

Martínez-Magadán, J M; Cartas-Rosado, A R; Oviedo-Roa, R; Cisneros-Dévora, R; Pons-Jiménez, M; Hernández-Altamirano, R; Zamudio-Rivera, L S

2018-03-01

Branched gemini zwitterionic liquids, which contain two zwitterionic moieties of linked quaternary-ammonium and carboxylate groups, are proposed as chemicals to be applied in the Enhanced Oil Recovery (EOR) from fractured carbonate reservoirs. The zwitterionic moieties are bridged between them through an alkyl chain containing 12 ether groups, and each zwitterionic moiety has attached a long alkyl tail including a CC double bond. A theoretical molecular mechanism over which EOR could rest, consisting on both the disaggregation of heavy oil and the reservoir-rock wettability alteration, was suggested. Results show that chemicals can both reduce the viscosity and remove heavy-oil molecules from the rock surface. Copyright © 2018. Published by Elsevier Inc.

Dynamics of miscible displacements in round tubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meiburg, E.; Maxworthy, T.; Chen, C.Y.

A combined experimental and numerical investigation of miscible two-phase flow in a capillary tube is reported. The fraction of fluid left behind on the wall is obtained as a function of the Peclet, Atwood, and Froude numbers. Scaling arguments are presented for two distinct flow regimes, dominated by diffusion and convection, respectively. In the latter one, an effective surface tension value can be estimated.

Galactic wind X-ray heating of the intergalactic medium during the Epoch of Reionization

NASA Astrophysics Data System (ADS)

Meiksin, Avery; Khochfar, Sadegh; Paardekooper, Jan-Pieter; Dalla Vecchia, Claudio; Kohn, Saul

2017-11-01

The diffuse soft X-ray emissivity from galactic winds is computed during the Epoch of Reionization (EoR). We consider two analytic models, a pressure-driven wind and a superbubble model, and a 3D cosmological simulation including gas dynamics from the First Billion Years (FiBY) project. The analytic models are normalized to match the diffuse X-ray emissivity of star-forming galaxies in the nearby Universe. The cosmological simulation uses physically motivated star formation and wind prescriptions, and includes radiative transfer corrections. The models and the simulation all are found to produce sufficient heating of the intergalactic medium to be detectable by current and planned radio facilities through 21 cm measurements during the EoR. While the analytic models predict a 21 cm emission signal relative to the cosmic microwave backgroundsets in by ztrans ≃ 8-10, the predicted signal in the FiBY simulation remains in absorption until reionization completes. The 21 cm absorption differential brightness temperature reaches a minimum of ΔT ≃ -130 to -200 mK, depending on model. Allowing for additional heat from high-mass X-ray binaries pushes the transition to emission to ztrans ≃ 10-12, with shallower absorption signatures having a minimum of ΔT ≃ -110 to -140 mK. The 21 cm signal may be a means of distinguishing between the wind models, with the superbubble model favouring earlier reheating. While an early transition to emission may indicate X-ray binaries dominate the reheating, a transition to emission as early as ztrans > 12 would suggest the presence of additional heat sources.

Phase Behaviour and Miscibility Studies of Collagen/Silk Fibroin Macromolecular System in Dilute Solutions and Solid State.

PubMed

Ghaeli, Ima; de Moraes, Mariana A; Beppu, Marisa M; Lewandowska, Katarzyna; Sionkowska, Alina; Ferreira-da-Silva, Frederico; Ferraz, Maria P; Monteiro, Fernando J

2017-08-18

Miscibility is an important issue in biopolymer blends for analysis of the behavior of polymer pairs through the detection of phase separation and improvement of the mechanical and physical properties of the blend. This study presents the formulation of a stable and one-phase mixture of collagen and regenerated silk fibroin (RSF), with the highest miscibility ratio between these two macromolecules, through inducing electrostatic interactions, using salt ions. For this aim, a ternary phase diagram was experimentally built for the mixtures, based on observations of phase behavior of blend solutions with various ratios. The miscibility behavior of the blend solutions in the miscible zones of the phase diagram was confirmed quantitatively by viscosimetric measurements. Assessing the effects of biopolymer mixing ratio and salt ions, before and after dialysis of blend solutions, revealed the importance of ion-specific interactions in the formation of coacervate-based materials containing collagen and RSF blends that can be used in pharmaceutical, drug delivery, and biomedical applications. Moreover, the conformational change of silk fibroin from random coil to beta sheet, in solution and in the final solid films, was detected by circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR), respectively. Scanning electron microscopy (SEM) exhibited alterations of surface morphology for the biocomposite films with different ratios. Surface contact angle measurement illustrated different hydrophobic properties for the blended film surfaces. Differential scanning calorimetry (DSC) showed that the formation of the beta sheet structure of silk fibroin enhances the thermal stability of the final blend films. Therefore, the novel method presented in this study resulted in the formation of biocomposite films whose physico-chemical properties can be tuned by silk fibroin conformational changes by applying different component mixing ratios.

Extending semi-numeric reionization models to the first stars and galaxies

NASA Astrophysics Data System (ADS)

Koh, Daegene; Wise, John H.

2018-03-01

Semi-numeric methods have made it possible to efficiently model the epoch of reionization (EoR). While most implementations involve a reduction to a simple three-parameter model, we introduce a new mass-dependent ionizing efficiency parameter that folds in physical parameters that are constrained by the latest numerical simulations. This new parametrization enables the effective modelling of a broad range of host halo masses containing ionizing sources, extending from the smallest Population III host haloes with M ˜ 106 M⊙, which are often ignored, to the rarest cosmic peaks with M ˜ 1012 M⊙ during EoR. We compare the resulting ionizing histories with a typical three-parameter model and also compare with the latest constraints from the Planck mission. Our model results in an optical depth due to Thomson scattering, τe = 0.057, that is consistent with Planck. The largest difference in our model is shown in the resulting bubble size distributions that peak at lower characteristic sizes and are broadened. We also consider the uncertainties of the various physical parameters, and comparing the resulting ionizing histories broadly disfavours a small contribution from galaxies. The smallest haloes cease a meaningful contribution to the ionizing photon budget after z = 10, implying that they play a role in determining the start of EoR and little else.

Measuring the Epoch of Reionization using [CII] Intensity Mapping with TIME-Pilot

NASA Astrophysics Data System (ADS)

Crites, Abigail; Bock, James; Bradford, Matt; Bumble, Bruce; Chang, Tzu-Ching; Cheng, Yun-Ting; Cooray, Asantha R.; Hailey-Dunsheath, Steve; Hunacek, Jonathon; Li, Chao-Te; O'Brient, Roger; Shirokoff, Erik; Staniszewski, Zachary; Shiu, Corwin; Uzgil, Bade; Zemcov, Michael B.; Sun, Guochao

2017-01-01

TIME-Pilot (the Tomographic Ionized carbon Intensity Mapping Experiment) is a new instrument designed to probe the epoch of reionization (EoR) by measuring the 158 um ionized carbon emission line [CII] from redshift 5 - 9. TIME-Pilot will also probe the molecular gas content of the universe during the epoch spanning the peak of star formation (z ~ 1 -3) by making an intensity mapping measurement of the CO transitions in the TIME-Pilot band (CO(3-2), CO(4-3), CO(5-4), and CO(6-5)). I will describe the instrument we are building which is an R of ~100 spectrometer sensitive to the 200-300 GHz radiation. The camera is designed to measure the line emission from galaxies using an intensity mapping technique. This instrument will allow us to detect the [CII] clustering fluctuations from faint galaxies during EoR and compare these measurements to predicted [CII] amplitudes from current models. The CO measurements will allow us to constrain models for galaxies at lower redshift. The [CII] intensity mapping measurements that will be made with TIME-Pilot and detailed measurements made with future more sensitive mm-wavelength spectrometers are complimentary to 21-cm measurements of the EoR and complimentary to direct detections of high redshift galaxies with HST, ALMA, and, in the future, JWST.

The inflammatory response to ruptured abdominal aortic aneurysm is altered by endovascular repair.

PubMed

Makar, R R; Badger, S A; O'Donnell, M E; Soong, C V; Lau, L L; Young, I S; Hannon, R J; Lee, B

2013-01-01

Introduction. Ruptured abdominal aortic aneurysm (rAAA) causes a significant inflammatory response. The study aims to investigate this response following endovascular and open repair of ruptured AAA. Patients and Methods. Consecutive rAAA patients had either endovascular aneurysm repair (EVAR) or open repair (OR). Blood samples were taken for cytokines, lipid hydroperoxides (LOOH), antioxidants, and neutrophil elastase/ α 1-anti-trypsin complexes (NE/AAT) before surgery, 6 hours after clamp release and 1, 3, 5 days postoperatively. Results. 30 patients were included in the study, with 14 undergoing eEVAR and 16 eOR, with comparable baseline comorbidities, age, and parameters. IL-6 peaked higher in eOR patients (P = 0.04), while p75TNFr was similar between groups except at day 5 (P = 0.04). The NE/AAT concentrations were higher in eOR patients (P = 0.01), particularly in the first postoperative day, and correlated with blood (r = 0.398, P = 0.029) and platelet (r = 0.424, P = 0.020) volume transfused. C-reactive protein rose and lipid hydroperoxide fell in both groups without significant intergroup difference. Vitamins C and E, lycopene, and β -carotene levels were similar between groups. Conclusion. EVAR is associated with lower systemic inflammatory response compared to OR. Its increased future use may thereby improve outcomes for patients.

The Inflammatory Response to Ruptured Abdominal Aortic Aneurysm Is Altered by Endovascular Repair

PubMed Central

Makar, R. R.; Badger, S. A.; O'Donnell, M. E.; Soong, C. V.; Lau, L. L.; Young, I. S.; Hannon, R. J.; Lee, B.

2013-01-01

Introduction. Ruptured abdominal aortic aneurysm (rAAA) causes a significant inflammatory response. The study aims to investigate this response following endovascular and open repair of ruptured AAA. Patients and Methods. Consecutive rAAA patients had either endovascular aneurysm repair (EVAR) or open repair (OR). Blood samples were taken for cytokines, lipid hydroperoxides (LOOH), antioxidants, and neutrophil elastase/α1-anti-trypsin complexes (NE/AAT) before surgery, 6 hours after clamp release and 1, 3, 5 days postoperatively. Results. 30 patients were included in the study, with 14 undergoing eEVAR and 16 eOR, with comparable baseline comorbidities, age, and parameters. IL-6 peaked higher in eOR patients (P = 0.04), while p75TNFr was similar between groups except at day 5 (P = 0.04). The NE/AAT concentrations were higher in eOR patients (P = 0.01), particularly in the first postoperative day, and correlated with blood (r = 0.398, P = 0.029) and platelet (r = 0.424, P = 0.020) volume transfused. C-reactive protein rose and lipid hydroperoxide fell in both groups without significant intergroup difference. Vitamins C and E, lycopene, and β-carotene levels were similar between groups. Conclusion. EVAR is associated with lower systemic inflammatory response compared to OR. Its increased future use may thereby improve outcomes for patients. PMID:24363936

Microseismic monitoring of CO2 injection at the Penn West Enhanced Oil Recovery pilot project, Canada: implications for detection of wellbore leakage.

PubMed

Martínez-Garzón, Patricia; Bohnhoff, Marco; Kwiatek, Grzegorz; Zambrano-Narváez, Gonzalo; Chalaturnyk, Rick

2013-09-02

A passive seismic monitoring campaign was carried out in the frame of a CO2-Enhanced Oil Recovery (EOR) pilot project in Alberta, Canada. Our analysis focuses on a two-week period during which prominent downhole pressure fluctuations in the reservoir were accompanied by a leakage of CO2 and CH4 along the monitoring well equipped with an array of short-period borehole geophones. We applied state of the art seismological processing schemes to the continuous seismic waveform recordings. During the analyzed time period we did not find evidence of induced micro-seismicity associated with CO2 injection. Instead, we identified signals related to the leakage of CO2 and CH4, in that seven out of the eight geophones show a clearly elevated noise level framing the onset time of leakage along the monitoring well. Our results confirm that micro-seismic monitoring of reservoir treatment can contribute towards improved reservoir monitoring and leakage detection.

Microseismic Monitoring of CO2 Injection at the Penn West Enhanced Oil Recovery Pilot Project, Canada: Implications for Detection of Wellbore Leakage

PubMed Central

Martínez-Garzón, Patricia; Bohnhoff, Marco; Kwiatek, Grzegorz; Zambrano-Narváez, Gonzalo; Chalaturnyk, Rick

2013-01-01

A passive seismic monitoring campaign was carried out in the frame of a CO2-Enhanced Oil Recovery (EOR) pilot project in Alberta, Canada. Our analysis focuses on a two-week period during which prominent downhole pressure fluctuations in the reservoir were accompanied by a leakage of CO2 and CH4 along the monitoring well equipped with an array of short-period borehole geophones. We applied state of the art seismological processing schemes to the continuous seismic waveform recordings. During the analyzed time period we did not find evidence of induced micro-seismicity associated with CO2 injection. Instead, we identified signals related to the leakage of CO2 and CH4, in that seven out of the eight geophones show a clearly elevated noise level framing the onset time of leakage along the monitoring well. Our results confirm that micro-seismic monitoring of reservoir treatment can contribute towards improved reservoir monitoring and leakage detection. PMID:24002229

Using improved technology for widespread application of a geological carbon sequestration study

NASA Astrophysics Data System (ADS)

Raney, J.

2013-12-01

The Kansas Geological Survey is part of an ongoing collaboration between DOE-NETL, academia, and the petroleum industry to investigate the feasibility of carbon utilization and storage in Kansas. Latest findings in the 25,000 mi2 study area in southern Kansas estimate CO2 storage capacity ranges from 8.8 to 75.5 billion metric tons in a deep Lower Orodovican-age Arbuckle saline aquifer. In addition, an estimated 100 million tonnes of CO2 could be used for extracting additional oil from Kansas' fields, making transitions to carbon management economic. This partnership has a rare opportunity to synchronize abundant, yet previously disseminated knowledge into a cohesive scientific process to optimize sequestration site selection and implementation strategies. Following a thorough characterization, a small-scale CO2 injection of 70,000 tonnes will be implemented in Wellington Field in Sumner County, including a five-plot miscible CO2-EOR flood of a Mississippian reservoir followed by the underlying Arbuckle saline aquifer. Best practices and lessons learned from the field study will improve estimates on CO2 storage capacity, plume migration models, and identify potential leakage pathways to pursue safe and effective geological carbon sequestration at commercial scales. A highly accessible and multifunctional online database is being developed throughout the study that integrates all acquired geological, physical, chemical, and hydrogeologic knowledge. This public database incorporates tens of thousands of data points into easily viewable formats for user downloads. An Interactive Project Map Viewer is a key mechanism to present the scientific research, and will delineate compartment candidates and reservoirs matching reference criteria or user defined attributes. This tool uses a familiar pan and zoom interface to filter regional project data or scale down to detailed digitized information from over 3,300 carefully selected preexisting Kansas wells. A Java-based log analysis program can combine public LAS data with privately owned digital petrophysical information to create refined cross sections with details on lithology and geochemistry. The interactive mapper displays geophysical surveys such as depth and time converted 3D seismic, gravity, magnetic, remote sensing, simulations, regional geologic base layers, and launches web-based well profile tools. Geocelluar models that demonstrate porosity, fault boundaries, seal continuity, and other hydrostratigraphic parameters will illustrate the presence of aquifers and caprocks. Dynamic models will use this input to simulate in situ CO2 plume migration and entrapment mechanisms over time. Additional outreach activities such as core workshops that showcase geological samples, conference presentations to describe technology experiences, and publishing peer-review journal articles will ensure the scientific research is delivered to the general public and useful in academia. Next steps will seek to enhance the current 3D depiction of the subsurface, leading to a direct visual connection between conceptual models and their supporting scientific evidence. Together, these tools aim to unite various industries to perform streamlined data analysis leading to a greater understanding of future geological carbon utilization and storage.

Serum estradiol:oocyte ratio as a predictor of reproductive outcome: an analysis of data from >9000 IVF cycles in the Republic of Ireland.

PubMed

Vaughan, Denis A; Harrity, Conor; Sills, E Scott; Mocanu, Edgar V

2016-04-01

The purpose of this study was to evaluate the serum estradiol (E2) per oocyte ratio (EOR) as a function of selected embryology events and reproductive outcomes with IVF. This retrospective analysis included all IVF cycles where oocyte collection and fresh transfer occurred between January 2001 and November 2012 at a single institution. Patients were divided by three age groups (<35, 35-39, and ≥40 years) and further stratified into nine groups based on EOR (measured in pmol/L/oocyte). Terminal serum E2 (pmol/mL) was recorded on day of hCG trigger administration, and fertilization rate, cleavage rate, number of good quality embryos, and reproductive outcomes were recorded for each IVF cycle. During the study interval, 9109 oocyte retrievals were performed for 5499 IVF patients (mean = 1.7 cycles/patient). A total of 63.4 % of transfers were performed on day 3 (n = 4926), while 36.6 % were carried out on day 5 (n = 2843). Clinical pregnancy rates were highest in patients with EOR of 250-750 and declined as this ratio increased, independent of patient age. While the odds ratio (OR) for clinical pregnancy where EOR = 250-750 vs. EOR > 1500 was 3.4 (p < 0.001; 95 % CI 2.67-4.34), no statistically significant correlation was seen in fertilization, cleavage rates or number of good quality embryos as a function of EOR. Predicting reproductive outcomes with IVF has great utility both for patients and providers. The former have the opportunity to build realistic expectations, and the latter are better able to counsel according to measured clinical parameters. A better understanding of follicular dynamics and ovarian response to gonadotropin stimulation could optimize IVF treatments going forward.

Epigenetic oxidative redox shift (EORS) theory of aging unifies the free radical and insulin signaling theories.

PubMed

Brewer, Gregory J

2010-03-01

Harman's free radical theory of aging posits that oxidized macromolecules accumulate with age to decrease function and shorten life-span. However, nutritional and genetic interventions to boost anti-oxidants have generally failed to increase life-span. Furthermore, the free radical theory fails to explain why exercise causes higher levels of oxyradical damage, but generally promotes healthy aging. The separate anti-aging paradigms of genetic or caloric reductions in the insulin signaling pathway is thought to slow the rate of living to reduce metabolism, but recent evidence from Westbrook and Bartke suggests metabolism actually increases in long-lived mice. To unify these disparate theories and data, here, we propose the epigenetic oxidative redox shift (EORS) theory of aging. According to EORS, sedentary behavior associated with age triggers an oxidized redox shift and impaired mitochondrial function. In order to maintain resting energy levels, aerobic glycolysis is upregulated by redox-sensitive transcription factors. As emphasized by DeGrey, the need to supply NAD(+) for glucose oxidation and maintain redox balance with impaired mitochondrial NADH oxidoreductase requires the upregulation of other oxidoreductases. In contrast to the 2% inefficiency of mitochondrial reduction of oxygen to the oxyradical, these other oxidoreductases enable glycolytic energy production with a deleterious 100% efficiency in generating oxyradicals. To avoid this catastrophic cycle, lactate dehydrogenase is upregulated at the expense of lactic acid acidosis. This metabolic shift is epigenetically enforced, as is insulin resistance to reduce mitochondrial turnover. The low mitochondrial capacity for efficient production of energy reinforces a downward spiral of more sedentary behavior leading to accelerated aging, increased organ failure with stress, impaired immune and vascular functions and brain aging. Several steps in the pathway are amenable to reversal for exit from the vicious cycle of EORS. Examples from our work in the aging rodent brain as well as other aging models are provided. Copyright 2010 Elsevier Inc. All rights reserved.

Awake craniotomy for gliomas in a high-field intraoperative magnetic resonance imaging suite: analysis of 42 cases.

PubMed

Maldaun, Marcos V C; Khawja, Shumaila N; Levine, Nicholas B; Rao, Ganesh; Lang, Frederick F; Weinberg, Jeffrey S; Tummala, Sudhakar; Cowles, Charles E; Ferson, David; Nguyen, Anh-Thuy; Sawaya, Raymond; Suki, Dima; Prabhu, Sujit S

2014-10-01

The object of this study was to describe the experience of combining awake craniotomy techniques with high-field (1.5 T) intraoperative MRI (iMRI) for tumors adjacent to eloquent cortex. From a prospective database the authors obtained and evaluated the records of all patients who had undergone awake craniotomy procedures with cortical and subcortical mapping in the iMRI suite. The integration of these two modalities was assessed with respect to safety, operative times, workflow, extent of resection (EOR), and neurological outcome. Between February 2010 and December 2011, 42 awake craniotomy procedures using iMRI were performed in 41 patients for the removal of intraaxial tumors. There were 31 left-sided and 11 right-sided tumors. In half of the cases (21 [50%] of 42), the patient was kept awake for both motor and speech mapping. The mean duration of surgery overall was 7.3 hours (range 4.0-13.9 hours). The median EOR overall was 90%, and gross-total resection (EOR ≥ 95%) was achieved in 17 cases (40.5%). After viewing the first MR images after initial resection, further resection was performed in 17 cases (40.5%); the mean EOR in these cases increased from 56% to 67% after further resection. No deficits were observed preoperatively in 33 cases (78.5%), and worsening neurological deficits were noted immediately after surgery in 11 cases (26.2%). At 1 month after surgery, however, worsened neurological function was observed in only 1 case (2.3%). There was a learning curve with regard to patient positioning and setup times, although it did not adversely affect patient outcomes. Awake craniotomy can be safely performed in a high-field (1.5 T) iMRI suite to maximize tumor resection in eloquent brain areas with an acceptable morbidity profile at 1 month.

Catalytic and electrocatalytic oxidation of ethanol over palladium-based nanoalloy catalysts.

PubMed

Yin, Jun; Shan, Shiyao; Ng, Mei Shan; Yang, Lefu; Mott, Derrick; Fang, Weiqin; Kang, Ning; Luo, Jin; Zhong, Chuan-Jian

2013-07-23

The control of the nanoscale composition and structure of alloy catalysts plays an important role in heterogeneous catalysis. This paper describes novel findings of an investigation for Pd-based nanoalloy catalysts (PdCo and PdCu) for ethanol oxidation reaction (EOR) in gas phase and alkaline electrolyte. Although the PdCo catalyst exhibits a mass activity similar to Pd, the PdCu catalyst is shown to display a much higher mass activity than Pd for the electrocatalytic EOR in alkaline electrolyte. This finding is consistent with the finding on the surface enrichment of Pd on the alloyed PdCu surface, in contrast to the surface enrichment of Co in the alloyed PdCo surface. The viability of C-C bond cleavage was also probed for the PdCu catalysts in both gas-phase and electrolyte-phase EOR. In the gas-phase reaction, although the catalytic conversion rate for CO2 product is higher over Pd than PdCu, the nanoalloy PdCu catalyst appears to suppress the formation of acetic acid, which is a significant portion of the product in the case of pure Pd catalyst. In the alkaline electrolyte, CO2 was detected from the gas phase above the electrolyte upon acid treatment following the electrolysis, along with traces of aldehyde and acetic acid. An analysis of the electrochemical properties indicates that the oxophilicity of the base metal alloyed with Pd, in addition to the surface enrichment of metals, may have played an important role in the observed difference of the catalytic and electrocatalytic activities. In comparison with Pd alloyed with Co, the results for Pd alloyed with Cu showed a more significant positive shift of the reduction potential of the oxygenated Pd species on the surface. These findings have important implications for further fine-tuning of the Pd nanoalloys in terms of base metal composition toward highly active and selective catalysts for EOR.

Mobility control experience in the Joffre Viking miscible CO[sub 2] flood

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luhning, R.W.; Stephenson, D.J.; Graham, A.G.

1993-08-01

This paper discusses mobility control in the Joffre Viking field miscible CO[sub 2] flood. Since 1984, three injection strategies have been tried: water-alternating-CO[sub 2] (WACO[sub 2]), continuous CO[sub 2], and simultaneous CO[sub 2] and water. The studies showed that simultaneous injection results in the best CO[sub 2] conformance. CO[sub 2]-foam injection has also been investigated.

Structure functions in decomposing Au-Pt systems

NASA Astrophysics Data System (ADS)

Glas, R.; Blaschko, O.; Rosta, L.

1992-09-01

The evolution of Au-Pt alloys quenched within the miscibility gap is investigated by small-angle neutron-scattering techniques. Moreover, in the vicinity of fundamental Bragg reflections the evolution of ``sideband'' satellites induced by a lattice-parameter modulation connected with the precipitation pattern is investigated by diffuse scattering methods. Structure functions are evaluated for a series of concentrations within the miscibility gap and compared to recent results of the literature.

Implications of surfactant-induced flow for miscible-displacement estimation of air-water interfacial areas in unsaturated porous media.

PubMed

Costanza-Robinson, Molly S; Zheng, Zheng; Henry, Eric J; Estabrook, Benjamin D; Littlefield, Malcolm H

2012-10-16

Surfactant miscible-displacement experiments represent a conventional means of estimating air-water interfacial area (A(I)) in unsaturated porous media. However, changes in surface tension during the experiment can potentially induce unsaturated flow, thereby altering interfacial areas and violating several fundamental method assumptions, including that of steady-state flow. In this work, the magnitude of surfactant-induced flow was quantified by monitoring moisture content and perturbations to effluent flow rate during miscible-displacement experiments conducted using a range of surfactant concentrations. For systems initially at 83% moisture saturation (S(W)), decreases of 18-43% S(W) occurred following surfactant introduction, with the magnitude and rate of drainage inversely related to the surface tension of the surfactant solution. Drainage induced by 0.1 mM sodium dodecyl benzene sulfonate, commonly used for A(I) estimation, resulted in effluent flow rate increases of up to 27% above steady-state conditions and is estimated to more than double the interfacial area over the course of the experiment. Depending on the surfactant concentration and the moisture content used to describe the system, A(I) estimates varied more than 3-fold. The magnitude of surfactant-induced flow is considerably larger than previously recognized and casts doubt on the reliability of A(I) estimation by surfactant miscible-displacement.

Giant Plasma Membrane Vesicles: An Experimental Tool for Probing the Effects of Drugs and Other Conditions on Membrane Domain Stability.

PubMed

Gerstle, Zoe; Desai, Rohan; Veatch, Sarah L

2018-01-01

Giant plasma membrane vesicles (GPMVs) are isolated directly from living cells and provide an alternative to vesicles constructed of synthetic or purified lipids as an experimental model system for use in a wide range of assays. GPMVs capture much of the compositional protein and lipid complexity of intact cell plasma membranes, are filled with cytoplasm, and are free from contamination with membranes from internal organelles. GPMVs often exhibit a miscibility transition below the growth temperature of their parent cells. GPMVs labeled with a fluorescent protein or lipid analog appear uniform on the micron-scale when imaged above the miscibility transition temperature, and separate into coexisting liquid domains with differing membrane compositions and physical properties below this temperature. The presence of this miscibility transition in isolated GPMVs suggests that a similar phase-like heterogeneity occurs in intact plasma membranes under growth conditions, albeit on smaller length scales. In this context, GPMVs provide a simple and controlled experimental system to explore how drugs and other environmental conditions alter the composition and stability of phase-like domains in intact cell membranes. This chapter describes methods to generate and isolate GPMVs from adherent mammalian cells and to interrogate their miscibility transition temperatures using fluorescence microscopy. © 2018 Elsevier Inc. All rights reserved.

Understanding How the Presence of Uniform Electric Fields Can Shift the Miscibility of Polystyrene/Poly(vinyl methyl ether) Blends

NASA Astrophysics Data System (ADS)

Kriisa, Annika; Roth, Connie B.

2015-03-01

Techniques which can externally control and manipulate the phase behavior of polymeric systems, without altering chemistry on a molecular level, have great practical benefits. One such possible mechanism is the use of electric fields, shown to cause interfacial instabilities, orientation of morphologies, and phase transitions in polymer blends and block copolymers. We have recently demonstrated that the presence of uniform electric fields can also strongly enhance the miscibility of polystyrene (PS) / poly(vinyl methyl ether) (PVME) blends [J. Chem. Phys. 2014, 141, 134908]. Using fluorescence to measure the phase separation temperature Ts of PS/PVME blends with and without electric fields, we show that Ts can be reproducibly and reversibly increased by 13.5 +/- 1.4 K for electric fields of 17 kV/mm for this lower critical solution temperature (LCST) blend. This increase in blend miscibility with electric fields represents some of the largest absolute shifts in Ts ever recorded, well outside of experimental error. The best theoretical prediction for the expected shift in Ts with electric field for this system is still two orders of magnitude smaller than that observed experimentally. We discuss the limitations of this theoretical prediction and consider possible factors affecting miscibility that may need to be also included.

Solubility and Speciation in the Water-Carbon Dioxide System

NASA Astrophysics Data System (ADS)

Abramson, E.; Bollengier, O.; Brown, J. M.

2016-12-01

The fluid-fluid miscibility surface of the water-carbon dioxide system contains broad regions (in pressure-composition space) exhibiting gradual variations in the temperature of miscibility; this is as expected. However, there is additionally a line of pressure, extending from roughly 2 GPa and 20 mole% CO2 to 6 GPa and 40 mole%, above which the temperature necessary to complete miscibility falls precipitously. This line, which closely approximates a hard limit, is hypothesized to demark a shift in speciation of dissolved CO2. In the same region of pressure the equilibrium limits of a new solid phase, composed of both water and CO2, have been determined. This new phase, the IR and Raman spectra of which led Wang et al.* to ascribe it to carbonic acid, has an observed associated aqueous form which must, in addition to the well-known bicarbonate and carbonate ions, affect the miscibilities of the system. Since zones of rapid subduction are expected to experience the regions of temperatures and pressures at which these equilibria are observed to shift, the chemical nature of these fluids is expected to undergo significant changes during the subduction process. * Wang H., Zeuschner J., Eremets M., Troyan I. and Willams J. (2016) Sci. Rep. 6, 19902-1-8

Subsurface Monitoring of CO2 Sequestration - A Review and Look Forward

NASA Astrophysics Data System (ADS)

Daley, T. M.

2012-12-01

The injection of CO2 into subsurface formations is at least 50 years old with large-scale utilization of CO2 for enhanced oil recovery (CO2-EOR) beginning in the 1970s. Early monitoring efforts had limited measurements in available boreholes. With growing interest in CO2 sequestration beginning in the 1990's, along with growth in geophysical reservoir monitoring, small to mid-size sequestration monitoring projects began to appear. The overall goals of a subsurface monitoring plan are to provide measurement of CO2 induced changes in subsurface properties at a range of spatial and temporal scales. The range of spatial scales allows tracking of the location and saturation of the plume with varying detail, while finer temporal sampling (up to continuous) allows better understanding of dynamic processes (e.g. multi-phase flow) and constraining of reservoir models. Early monitoring of small scale pilots associated with CO2-EOR (e.g., the McElroy field and the Lost Hills field), developed many of the methodologies including tomographic imaging and multi-physics measurements. Large (reservoir) scale sequestration monitoring began with the Sleipner and Weyburn projects. Typically, large scale monitoring, such as 4D surface seismic, has limited temporal sampling due to costs. Smaller scale pilots can allow more frequent measurements as either individual time-lapse 'snapshots' or as continuous monitoring. Pilot monitoring examples include the Frio, Nagaoka and Otway pilots using repeated well logging, crosswell imaging, vertical seismic profiles and CASSM (continuous active-source seismic monitoring). For saline reservoir sequestration projects, there is typically integration of characterization and monitoring, since the sites are not pre-characterized resource developments (oil or gas), which reinforces the need for multi-scale measurements. As we move beyond pilot sites, we need to quantify CO2 plume and reservoir properties (e.g. pressure) over large scales, while still obtaining high resolution. Typically the high-resolution (spatial and temporal) tools are deployed in permanent or semi-permanent borehole installations, where special well design may be necessary, such as non-conductive casing for electrical surveys. Effective utilization of monitoring wells requires an approach of modular borehole monitoring (MBM) were multiple measurements can be made. An example is recent work at the Citronelle pilot injection site where an MBM package with seismic, fluid sampling and distributed fiber sensing was deployed. For future large scale sequestration monitoring, an adaptive borehole-monitoring program is proposed.

Status of Geological Storage of CO2 as Part of Negative Emissions Strategy

NASA Astrophysics Data System (ADS)

Benson, S. M.

2014-12-01

Recent analyses show that many GHG stabilization scenarios require technologies that permanently extract CO2 from the atmosphere -so-called "net negative emissions." Among the most promising negative emissions approaches is bioenergy with carbon capture and storage (BECCS). The most mature options for CO2 storage are in sedimentary rocks located in thick sedimentary basins. Within those basins, CO2 can be stored either in depleted or depleting hydrocarbon formations or in so-called saline aquifers. In addition to the economic costs of bioenergy with CO2 capture, key to the success of and scale at which BECCS can contribute to negative emissions is the ability to store quantities on the order of 1 Gt per year of CO2. Today, about 65 Mt of CO2 per year are injected underground for the purposes of enhancing oil recovery (CO2-EOR) or for CO2 storage, the vast majority being for CO2-EOR. Achieving 1 Gt per year of negative emissions will require a 15-fold scale up of the current injection operations. This paper will review the conditions necessary for storage at this scale, identify what has been learned from nearly 2 decades of experience with CO2 storage that provides insight into the feasibility of CO2 storage on this scale, and identify critical issues that remain to be resolved to meet these ambitious negative emissions targets. Critical technological issues include but are not limited to: the amount of CO2 storage capacity that is available and where it is located in relation to biomass energy resources; identification of sustainable injection rates and how this depends on the properties of the geological formation; the extent to which water extraction will be required to manage the magnitude of pressure buildup; identification of regions at high risk for induced seismicity that could damage structures and infrastructure; and selection of sites with a adequate seals to permanently contain CO2. Social, economic and political issues are also important: including the support for and confidence in the projects by the local population; scale at which these projects are financially feasible; resolution of issues such as who pays and who benefits from these projects; and development of regulatory frameworks that are at the same time, environmentally protective and not overly burdensome.

Transient dynamics of a quantum-dot: From Kondo regime to mixed valence and to empty orbital regimes

NASA Astrophysics Data System (ADS)

Cheng, YongXi; Li, ZhenHua; Wei, JianHua; Nie, YiHang; Yan, YiJing

2018-04-01

Based on the hierarchical equations of motion approach, we study the time-dependent transport properties of a strongly correlated quantum dot system in the Kondo regime (KR), mixed valence regime (MVR), and empty orbital regime (EOR). We find that the transient current in KR shows the strongest nonlinear response and the most distinct oscillation behaviors. Both behaviors become weaker in MVR and diminish in EOR. To understand the physical insight, we examine also the corresponding dot occupancies and the spectral functions, with their dependence on the Coulomb interaction, temperature, and applied step bias voltage. The above nonlinear and oscillation behaviors could be understood as the interplay between dynamical Kondo resonance and single electron resonant-tunneling.

Investigation of immiscible systems and potential applications

NASA Technical Reports Server (NTRS)

Markworth, A. J.; Oldfield, W.; Duga, J.; Gelles, S. H.

1975-01-01

The droplet coalescence kinetics at 0 g and 1 g were considered for two systems which contained liquid droplets in a host liquid. One of these (Al-In) typified a system containing a liquid phase miscibility gap and the order (oil-water) a mixture of two essentially insoluble liquids. A number of coalescence mechanisms potentially prominent at low g in this system were analyzed and explanations are presented for the observed unusual stability of the emulsion. Ground base experiments were conducted on the coalescence of In droplets in and Al-In alloy during cooling through the miscibility gap at different cooling rates. These were in qualitative agreement with the computer simulation. Potential applications for systems with liquid phase miscibility gaps were explored. Possibilities included superconductors, electrical contact materials, superplastic materials, catalysts, magnetic materials, and others. The role of space processing in their production was also analyzed.

Numerical simulation of miscible viscous fingering with viscosity change in a displacing fluid by chemical reaction

NASA Astrophysics Data System (ADS)

Omori, Keiichiro; Nagatsu, Yuichiro

2017-11-01

Viscous fingering (VF) with viscosity changes by chemical reactions in case of miscible systems have been investigated both experimentally and theoretically in the recent years. Nagatsu et al. investigated experimentally miscible VF in which viscosity of the displaced fluid or the displacing one is changed by fast chemical reaction They showed that VF was more dense by the viscosity increase whereas less dense by the viscosity increase regardless of whether the viscosity change occurs in the displaced fluid or displacing one. From a theoretical viewpoint, numerical simulation performed on the reactive VF where viscosity of the displaced fluid is changed by instantaneously fast chemical reaction. The results had a good agreement with those in the corresponding experiment. In this work, we have conducted numerical simulation on such reactive VF where viscosity of the displacing fluid is changed. We have found the results have a good agreement with the corresponding experimental ones.

Miscibility phase diagram of ring-polymer blends: A topological effect.

PubMed

Sakaue, Takahiro; Nakajima, Chihiro H

2016-04-01

The miscibility of polymer blends, a classical problem in polymer science, may be altered, if one or both of the component do not have chain ends. Based on the idea of topological volume, we propose a mean-field theory to clarify how the topological constraints in ring polymers affect the phase behavior of the blends. While the large enhancement of the miscibility is expected for ring-linear polymer blends, the opposite trend toward demixing, albeit comparatively weak, is predicted for ring-ring polymer blends. Scaling formulas for the shift of critical point for both cases are derived. We discuss the valid range of the present theory, and the crossover to the linear polymer blends behaviors, which is expected for short chains. These analyses put forward a view that the topological constraints could be represented as an effective excluded-volume effects, in which the topological length plays a role of the screening factor.

Analytical and variational numerical methods for unstable miscible displacement flows in porous media

NASA Astrophysics Data System (ADS)

Scovazzi, Guglielmo; Wheeler, Mary F.; Mikelić, Andro; Lee, Sanghyun

2017-04-01

The miscible displacement of one fluid by another in a porous medium has received considerable attention in subsurface, environmental and petroleum engineering applications. When a fluid of higher mobility displaces another of lower mobility, unstable patterns - referred to as viscous fingering - may arise. Their physical and mathematical study has been the object of numerous investigations over the past century. The objective of this paper is to present a review of these contributions with particular emphasis on variational methods. These algorithms are tailored to real field applications thanks to their advanced features: handling of general complex geometries, robustness in the presence of rough tensor coefficients, low sensitivity to mesh orientation in advection dominated scenarios, and provable convergence with fully unstructured grids. This paper is dedicated to the memory of Dr. Jim Douglas Jr., for his seminal contributions to miscible displacement and variational numerical methods.

Computer-aided method for the determination of Hansen solubility parameters. Application to the miscibility of refrigerating lubricant and new refrigerant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Remigy, J.C.; Nakache, E.; Brechot, P.D.

This article presents a method which allows one to find the Hansen solubility parameters by means of data processing. In the first part, the authors present the thermodynamical principle of Hansen parameters, and then they explain the model used to find parameters from experimental data. They validate the method by studying the solubility parameters of CFC-12 (dichlorodifluoromethane), HFC-134a (1,1,1,2-tetrafluoroethane), neopentylglycol esters, trimethylolpropane esters, dipentaerythritol esters, and pentaerythritol esters. Then, the variation of Hansen parameters are studied as well as the relation between the miscibility temperature (the temperature at which a blend passes from the miscible state to the immiscible state)more » and the interaction distance. The authors establish the critical interaction distance of HFC-134a which determines the solubility limit and they study its variation with temperature.« less

The Hydrogen Epoch of Reionization Array Dish. I. Beam Pattern Measurements and Science Implications

NASA Astrophysics Data System (ADS)

Neben, Abraham R.; Bradley, Richard F.; Hewitt, Jacqueline N.; DeBoer, David R.; Parsons, Aaron R.; Aguirre, James E.; Ali, Zaki S.; Cheng, Carina; Ewall-Wice, Aaron; Patra, Nipanjana; Thyagarajan, Nithyanandan; Bowman, Judd; Dickenson, Roger; Dillon, Joshua S.; Doolittle, Phillip; Egan, Dennis; Hedrick, Mike; Jacobs, Daniel C.; Kohn, Saul A.; Klima, Patricia J.; Moodley, Kavilan; Saliwanchik, Benjamin R. B.; Schaffner, Patrick; Shelton, John; Taylor, H. A.; Taylor, Rusty; Tegmark, Max; Wirt, Butch; Zheng, Haoxuan

2016-08-01

The Hydrogen Epoch of Reionization Array (HERA) is a radio interferometer aiming to detect the power spectrum of 21 cm fluctuations from neutral hydrogen from the epoch of reionization (EOR). Drawing on lessons from the Murchison Widefield Array and the Precision Array for Probing the EOR, HERA is a hexagonal array of large (14 m diameter) dishes with suspended dipole feeds. The dish not only determines overall sensitivity, but also affects the observed frequency structure of foregrounds in the interferometer. This is the first of a series of four papers characterizing the frequency and angular response of the dish with simulations and measurements. In this paper, we focus on the angular response (I.e., power pattern), which sets the relative weighting between sky regions of high and low delay and thus apparent source frequency structure. We measure the angular response at 137 MHz using the ORBCOMM beam mapping system of Neben et al. We measure a collecting area of 93 m2 in the optimal dish/feed configuration, implying that HERA-320 should detect the EOR power spectrum at z ˜ 9 with a signal-to-noise ratio of 12.7 using a foreground avoidance approach with a single season of observations and 74.3 using a foreground subtraction approach. Finally, we study the impact of these beam measurements on the distribution of foregrounds in Fourier space.

Synergetic effect of palladium-ruthenium nanostructures for ethanol electrooxidation in alkaline media

NASA Astrophysics Data System (ADS)

Monyoncho, Evans A.; Ntais, Spyridon; Soares, Felipo; Woo, Tom K.; Baranova, Elena A.

2015-08-01

Palladium-ruthenium nanoparticles supported on carbon PdxRu1-x/C (x = 1, 0.99, 0.95, 0.90, 0.80, 0.50) were prepared using a polyol method for ethanol electrooxidation in alkaline media. The resulting bimetallic catalysts were found to be primarily a mix of Pd metal, Ru oxides and Pd oxides. Their electrocatalytic activity towards ethanol oxidation reaction (EOR) in 1M KOH was studied using cyclic voltammetry and chronoamperometry techniques. Addition of 1-10 at.% Ru to Pd not only lowers the onset oxidation potential for EOR but also produces higher current densities at lower potentials compared to Pd by itself. Thus, Pd90Ru10/C and Pd99Ru1/C provide the current densities of up to six times those of Pd/C at -0.96 V and -0.67 V vs MSE, respectively. The current density at different potentials was found to be dependent on the surface composition of PdxRu1-x/C nanostructures. Pd90Ru10/C catalyst with more surface oxides was found to be active at lower potential compared to Pd99Ru1/C with less surface oxides, which is active at higher potentials. The steady-state current densities of the two best catalysts, Pd90Ru10/C and Pd99Ru1/C, showed minimal surface deactivation from EOR intermediates/products during chronoamperometry.

Ultrasmall PdmMn1-mOx binary alloyed nanoparticles on graphene catalysts for ethanol oxidation in alkaline media

NASA Astrophysics Data System (ADS)

Ahmed, Mohammad Shamsuddin; Park, Dongchul; Jeon, Seungwon

2016-03-01

A rare combination of graphene (G)-supported palladium and manganese in mixed-oxides binary alloyed catalysts (BACs) have been synthesized with the addition of Pd and Mn metals in various ratios (G/PdmMn1-mOx) through a facile wet-chemical method and employed as an efficient anode catalyst for ethanol oxidation reaction (EOR) in alkaline fuel cells. The as prepared G/PdmMn1-mOx BACs have been characterized by several instrumental techniques; the transmission electron microscopy images show that the ultrafine alloyed nanoparticles (NPs) are excellently monodispersed onto the G. The Pd and Mn in G/PdmMn1-mOx BACs have been alloyed homogeneously, and Mn presents in mixed-oxidized form that resulted by X-ray diffraction. The electrochemical performances, kinetics and stability of these catalysts toward EOR have been evaluated using cyclic voltammetry in 1 M KOH electrolyte. Among all G/PdmMn1-mOx BACs, the G/Pd0.5Mn0.5Ox catalyst has shown much superior mass activity and incredible stability than that of pure Pd catalysts (G/Pd1Mn0Ox, Pd/C and Pt/C). The well dispersion, ultrafine size of NPs and higher degree of alloying are the key factor for enhanced and stable EOR electrocatalysis on G/Pd0.5Mn0.5Ox.

Quasi-zero-dimensional cobalt-doped CeO2 dots on Pd catalysts for alcohol electro-oxidation with enhanced poisoning-tolerance.

PubMed

Tan, Qiang; Zhu, Haiyan; Guo, Shengwu; Chen, Yuanzhen; Jiang, Tao; Shu, Chengyong; Chong, Shaokun; Hultman, Benjamin; Liu, Yongning; Wu, Gang

2017-08-31

Deactivation of an anode catalyst resulting from the poisoning of CO ad -like intermediates is one of the major problems for methanol and ethanol electro-oxidation reactions (MOR & EOR), and remains a grand challenge towards achieving high performance for direct alcohol fuel cells (DAFCs). Herein, we report a new approach for the preparation of ultrafine cobalt-doped CeO 2 dots (Co-CeO 2 , d = 3.6 nm), which can be an effective anti-poisoning promoter for Pd catalysts towards MOR and EOR in alkaline media. Compared to Pd/CeO 2 and pure Pd, the hybrid Pd/Co-CeO 2 nanocomposite catalyst exhibited a much enhanced activity and remarkable anti-poisoning ability for both MOR and EOR. The nanocomposite catalyst showed much higher mass activity (4×) than a state-of-the-art PtRu catalyst. The promotional mechanism was elucidated using extensive characterization and density-functional theory (DFT). A bifunctional effect of the Co-CeO 2 dots was discovered to be due to (i) an enhanced electronic interaction between Co-CeO 2 and Pd dots and (ii) the increased oxygen storage capacity of Co-CeO 2 dots to facilitate the oxidation of CO ad . Therefore, the Pd/Co-CeO 2 nanocomposite appears to be a promising catalyst for advanced DAFCs with low cost and high performance.

Tuning of platinum nano-particles by Au usage in their binary alloy for direct ethanol fuel cell: Controlled synthesis, electrode kinetics and mechanistic interpretation

NASA Astrophysics Data System (ADS)

Dutta, Abhijit; Mondal, Achintya; Datta, Jayati

2015-06-01

Understanding of the electrode-kinetics and mechanism of ethanol oxidation reaction (EOR) is of considerable interest for optimizing electro-catalysis in direct ethanol fuel cell (DEFC). This work attempts to design Pt based electro-catalyst on carbon support, tuned with gold nano-particles (NPs), for their use in DEFC operating in alkaline medium. The platinum-gold alloyed NPs are synthesized at desired compositions and size (2-10 nm) by controlled borohydride reduction method and successfully characterized by XRD, TEM, EDS and XPS techniques. The kinetic parameters along with the activation energies for the EOR are evaluated over the temperature range 20-80 °C and the oxidation reaction products estimated through ion chromatographic analysis. Compared to single Pt/C catalyst, the over potential of EOR is reduced by ca. 500 mV, at the onset during the reaction, for PtAu/C alloy with only 23% Pt content demonstrating the ability of Au and/or its surface oxides providing oxygen species at much lower potentials compared to Pt. Furthermore, a considerable increase in the peak power density (>191%) is observed in an in-house fabricated direct ethanol anion exchange membrane fuel cell, DE(AEM)FC using the best performing Au covered Pt electrode (23% Pt) compared to the monometallic Pt catalyst.

THE HYDROGEN EPOCH OF REIONIZATION ARRAY DISH. I. BEAM PATTERN MEASUREMENTS AND SCIENCE IMPLICATIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neben, Abraham R.; Hewitt, Jacqueline N.; Ewall-Wice, Aaron

2016-08-01

The Hydrogen Epoch of Reionization Array (HERA) is a radio interferometer aiming to detect the power spectrum of 21 cm fluctuations from neutral hydrogen from the epoch of reionization (EOR). Drawing on lessons from the Murchison Widefield Array and the Precision Array for Probing the EOR, HERA is a hexagonal array of large (14 m diameter) dishes with suspended dipole feeds. The dish not only determines overall sensitivity, but also affects the observed frequency structure of foregrounds in the interferometer. This is the first of a series of four papers characterizing the frequency and angular response of the dish withmore » simulations and measurements. In this paper, we focus on the angular response (i.e., power pattern), which sets the relative weighting between sky regions of high and low delay and thus apparent source frequency structure. We measure the angular response at 137 MHz using the ORBCOMM beam mapping system of Neben et al. We measure a collecting area of 93 m{sup 2} in the optimal dish/feed configuration, implying that HERA-320 should detect the EOR power spectrum at z ∼ 9 with a signal-to-noise ratio of 12.7 using a foreground avoidance approach with a single season of observations and 74.3 using a foreground subtraction approach. Finally, we study the impact of these beam measurements on the distribution of foregrounds in Fourier space.« less

Ternary electrocatalysts for oxidizing ethanol to carbon dioxide: making ir capable of splitting C-C bond.

PubMed

Li, Meng; Cullen, David A; Sasaki, Kotaro; Marinkovic, Nebojsa S; More, Karren; Adzic, Radoslav R

2013-01-09

Splitting the C-C bond is the main obstacle to electrooxidation of ethanol (EOR) to CO(2). We recently demonstrated that the ternary PtRhSnO(2) electrocatalyst can accomplish that reaction at room temperature with Rh having a unique capability to split the C-C bond. In this article, we report the finding that Ir can be induced to split the C-C bond as a component of the ternary catalyst. We characterized and compared the properties of several carbon-supported nanoparticle (NP) electrocatalysts comprising a SnO(2) NP core decorated with multimetallic nanoislands (MM' = PtIr, PtRh, IrRh, PtIrRh) prepared using a seeded growth approach. An array of characterization techniques were employed to establish the composition and architecture of the synthesized MM'/SnO(2) NPs, while electrochemical and in situ infrared reflection absorption spectroscopy studies elucidated trends in activity and the nature of the reaction intermediates and products. Both EOR reactivity and selectivity toward CO(2) formation of several of these MM'/SnO(2)/C electrocatalysts are significantly higher compared to conventional Pt/C and Pt/SnO(2)/C catalysts. We demonstrate that the PtIr/SnO(2)/C catalyst with high Ir content shows outstanding catalytic properties with the most negative EOR onset potential and reasonably good selectivity toward ethanol complete oxidation to CO(2).

Quantitative Tumor Segmentation for Evaluation of Extent of Glioblastoma Resection to Facilitate Multisite Clinical Trials12

PubMed Central

Cordova, James S; Schreibmann, Eduard; Hadjipanayis, Costas G; Guo, Ying; Shu, Hui-Kuo G; Shim, Hyunsuk; Holder, Chad A

2014-01-01

Standard-of-care therapy for glioblastomas, the most common and aggressive primary adult brain neoplasm, is maximal safe resection, followed by radiation and chemotherapy. Because maximizing resection may be beneficial for these patients, improving tumor extent of resection (EOR) with methods such as intraoperative 5-aminolevulinic acid fluorescence-guided surgery (FGS) is currently under evaluation. However, it is difficult to reproducibly judge EOR in these studies due to the lack of reliable tumor segmentation methods, especially for postoperative magnetic resonance imaging (MRI) scans. Therefore, a reliable, easily distributable segmentation method is needed to permit valid comparison, especially across multiple sites. We report a segmentation method that combines versatile region-of-interest blob generation with automated clustering methods. We applied this to glioblastoma cases undergoing FGS and matched controls to illustrate the method's reliability and accuracy. Agreement and interrater variability between segmentations were assessed using the concordance correlation coefficient, and spatial accuracy was determined using the Dice similarity index and mean Euclidean distance. Fuzzy C-means clustering with three classes was the best performing method, generating volumes with high agreement with manual contouring and high interrater agreement preoperatively and postoperatively. The proposed segmentation method allows tumor volume measurements of contrast-enhanced T1-weighted images in the unbiased, reproducible fashion necessary for quantifying EOR in multicenter trials. PMID:24772206

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murray, S. G.; Trott, C. M.; Jordan, C. H.

We present a sophisticated statistical point-source foreground model for low-frequency radio Epoch of Reionization (EoR) experiments using the 21 cm neutral hydrogen emission line. Motivated by our understanding of the low-frequency radio sky, we enhance the realism of two model components compared with existing models: the source count distributions as a function of flux density and spatial position (source clustering), extending current formalisms for the foreground covariance of 2D power-spectral modes in 21 cm EoR experiments. The former we generalize to an arbitrarily broken power law, and the latter to an arbitrary isotropically correlated field. This paper presents expressions formore » the modified covariance under these extensions, and shows that for a more realistic source spatial distribution, extra covariance arises in the EoR window that was previously unaccounted for. Failure to include this contribution can yield bias in the final power-spectrum and under-estimate uncertainties, potentially leading to a false detection of signal. The extent of this effect is uncertain, owing to ignorance of physical model parameters, but we show that it is dependent on the relative abundance of faint sources, to the effect that our extension will become more important for future deep surveys. Finally, we show that under some parameter choices, ignoring source clustering can lead to false detections on large scales, due to both the induced bias and an artificial reduction in the estimated measurement uncertainty.« less

Activation of porous MOF materials

DOEpatents

Hupp, Joseph T; Farha, Omar K

2013-04-23

A method for the treatment of solvent-containing MOF material to increase its internal surface area involves introducing a liquid into the MOF in which liquid the solvent is miscible, subjecting the MOF to supercritical conditions for a time to form supercritical fluid, and releasing the supercritical conditions to remove the supercritical fluid from the MOF. Prior to introducing the liquid into the MOF, occluded reaction solvent, such as DEF or DMF, in the MOF can be exchanged for the miscible solvent.

Activation of porous MOF materials

DOEpatents

Hupp, Joseph T; Farha, Omar K

2014-04-01

A method for the treatment of solvent-containing MOF material to increase its internal surface area involves introducing a liquid into the MOF in which liquid the solvent is miscible, subjecting the MOF to supercritical conditions for a time to form supercritical fluid, and releasing the supercritical conditions to remove the supercritcal fluid from the MOF. Prior to introducing the liquid into the MOF, occluded reaction solvent, such as DEF or DMF, in the MOF can be exchanged for the miscible solvent.

Alloy catalysts for fuel cell-based alcohol sensors

NASA Astrophysics Data System (ADS)

Ghavidel, Mohammadreza Zamanzad

Direct ethanol fuel cells (DEFCs) are attractive from both economic and environmental standpoints for generating renewable energy and powering vehicles and portable electronic devices. There is a great interest recently in developing DEFC systems. The cost and performance of the DEFCs are mainly controlled by the Pt-base catalysts used at each electrode. In addition to energy conversion, DEFC technology is commonly employed in the fuel-cell based breath alcohol sensors (BrAS). BrAS is a device commonly used to measure blood alcohol concentration (BAC) and enforce drinking and driving laws. The BrAS is non-invasive and has a fast respond time. However, one of the most important drawback of the commercially available BrAS is the very high loading of Pt employed. One well-known and cost effective method to reduce the Pt loading is developing Pt-alloy catalysts. Recent studies have shown that Pt-transition metal alloy catalysts enhanced the electroactivity while decreasing the required loadings of the Pt catalysts. In this thesis, carbon supported Pt-Mn and Pt-Cu electrocatalysts were synthesized by different methods and the effects of heat treatment and structural modification on the ethanol oxidation reaction (EOR) activity, oxygen reduction reaction (ORR) activity and durability of these samples were thoroughly studied. Finally, the selected Pt-Mn and Pt-Cu samples with the highest EOR activity were examined in a prototype BrAS system and compared to the Pt/C and Pt 3Sn/C commercial electrocatalysts. Studies on the Pt-Mn catalysts produced with and without additives indicate that adding trisodium citrate (SC) to the impregnation solution improved the particle dispersion, decreased particle sizes and reduced the time required for heat treatment. Further studies show that the optimum weight ratio of SC to the metal loading in the impregnation solution was 2:1 and optimum results achieved at pH lower than 4. In addition, powder X-ray diffraction (XRD) analyses indicate that the optimum heat treatment temperature was 700 °C where a uniform ordered PtMn intermetallic phase was formed. Although the electrochemical active surface area (ECSA) decreased due to the heat treatment, the EOR activity of Pt-Mn samples was improved. Moreover, it was shown that the heat-treated samples prepared in the presence of SC showed superior the EOR activity compared to the samples made without SC. The Pt-Cu/C alloys were produced by three different methods: impregnation, impregnation in the presence of sodium citrate and microwave assisted polyol methods. These studies showed that the polyol method was the optimum method to produce the Pt-Cu alloy. The XRD analysis indicates that the heat treatment at 700 °C developed catalysts rich in the PtCu and PtCu3 ordered phases. The highest EOR activity was measured for the Pt-Cu/C-POL (sample made by the polyol method) and heat treated at 700 °C for 1h. Comparing the EOR activity of the Pt-Cu and Pt-Mn samples also demonstrates that the heat treated Pt-Cu/C-POL sample showed higher EOR activity compared to the Pt-Mn samples. These results indicate that the benefits of thermally treating alloy nanoparticles could outweigh any activity losses that may occur due to the particle size growth and the ECSA loss. Besides, accelerated stress tests (ASTs) illustrate that the heat treatment improved the durability of the Pt-Mn and Pt-Cu samples. The durability and EOR activity of the heat treated Pt-Mn and Pt-Cu samples was similar or better than commercial samples. On the other hand, the ORR activity of Pt-Mn and Pt-Cu after the heat treatment was slightly lower than the commercial samples but the ORR activity loss can be compensated by the economic benefits from using the lower Pt loading. Finally, studying the alcohol sensing characteristic of different samples shows that the heat treated Pt-Mn and Pt-Cu catalysts could be used for the ethanol sensing. Additionally, among the different commercial samples tested for ethanol sensing, Pt-Sn/C showed the highest sensitivity but with slightly higher standard deviation. Further studies on the Pt- Cu/C and Pt-Mn/C samples indicate that the heat treatment improved the sensitivity of these samples and the highest normalized sensitivity among all the samples belonged to the Pt- Cu/C-POL (sample produced by polyol method) and heat treated at 700 °C. It can be concluded that the heat treated Pt-Mn and Pt-Cu samples could be used as an alternative to replace Pt black in commercial sensors which would dramatically decrease the Pt loading. This could reduce the price and increase the sensitivity of commercial alcohol sensors.

Miscibility and Phase Behavior of N-Acylethanolamine/Diacylphosphatidylethanolamine Binary Mixtures of Matched Acyl Chainlengths (n = 14, 16)

PubMed Central

Kamlekar, Ravi Kanth; Satyanarayana, S.; Marsh, Derek; Swamy, Musti J.

2007-01-01

The miscibility and phase behavior of hydrated binary mixtures of two N-acylethanolamines (NAEs), N-myristoylethanolamine (NMEA), and N-palmitoylethanolamine (NPEA), with the corresponding diacyl phosphatidylethanolamines (PEs), dimyristoylphosphatidylethanolamine (DMPE), and dipalmitoylphosphatidylethanolamine (DPPE), respectively, have been investigated by differential scanning calorimetry (DSC), spin-label electron spin resonance (ESR), and 31P-NMR spectroscopy. Temperature-composition phase diagrams for both NMEA/DMPE and NPEA/DPPE binary systems were established from high sensitivity DSC. The structures of the phases involved were determined by 31P-NMR spectroscopy. For both systems, complete miscibility in the fluid and gel phases is indicated by DSC and ESR, up to 35 mol % of NMEA in DMPE and 40 mol % of NPEA in DPPE. At higher contents of the NAEs, extensive solid-fluid phase separation and solid-solid immiscibility occur depending on the temperature. Characterization of the structures of the mixtures formed with 31P-NMR spectroscopy shows that up to 75 mol % of NAE, both DMPE and DPPE form lamellar structures in the gel phase as well as up to at least 65°C in the fluid phase. ESR spectra of phosphatidylcholine spin labeled at the C-5 position in the sn-2 acyl chain present at a probe concentration of 1 mol % exhibit strong spin-spin broadening in the low-temperature region for both systems, suggesting that the acyl chains pack very tightly and exclude the spin label. However, spectra recorded in the fluid phase do not exhibit any spin-spin broadening and indicate complete miscibility of the two components. The miscibility of NAE and diacyl PE of matched chainlengths is significantly less than that found earlier for NPEA and dipalmitoylphosphatidylcholine, an observation that is consistent with the notion that the NAEs are most likely stored as their precursor lipids (N-acyl PEs) and are generated only when the system is subjected to membrane stress. PMID:17369415

Preparation of polydopamine nanocapsules in a miscible tetrahydrofuran-buffer mixture.

PubMed

Ni, Yun-Zhou; Jiang, Wen-Feng; Tong, Gang-Sheng; Chen, Jian-Xin; Wang, Jie; Li, Hui-Mei; Yu, Chun-Yang; Huang, Xiao-hua; Zhou, Yong-Feng

2015-01-21

A miscible tetrahydrofuran-tris buffer mixture has been used to fabricate polydopamine hollow capsules with a size of 200 nm and with a shell thickness of 40 nm. An unusual non-emulsion soft template mechanism has been disclosed to explain the formation of capsules. The results indicate that the capsule structure is highly dependent on the volume fraction of tetrahydrofuran as well as the solvent, and the shell thickness of capsules can be controlled by adjusting the reaction time and dopamine concentration.

Video of Miscible Fluid Experiment Conducted on NASA Low Gravity Airplane

NASA Technical Reports Server (NTRS)

2003-01-01

This is a video of dyed water being injected into glycerin in a 2.2 centimeter (cm) diameter test tube. The experiment was conducted on the KC-135 aircraft, a NASA plane that creates microgravity and 2g conditions as it maneuvers through multiple parabolas. The water is less dense and so it rises to the top of the glycerin. The goal of the experiment was to determine if a blob of a miscible fluid would spontaneously become spherical in a microgravity environment.

Nonhuman primate model of polytraumatic hemorrhagic shock recapitulates early platelet dysfunction observed following severe injury in humans.

PubMed

Schaub, Leasha J; Moore, Hunter B; Cap, Andrew P; Glaser, Jacob J; Moore, Ernest E; Sheppard, Forest R

2017-03-01

Platelet dysfunction has been described as an early component of trauma-induced coagulopathy. The platelet component of trauma-induced coagulopathy remains to be fully elucidated and translatable animal models are required to facilitate mechanistic investigations. We sought to determine if the early platelet dysfunction described in trauma patients could be recapitulated in a nonhuman primate model of polytraumatic hemorrhagic shock. Twenty-four male rhesus macaques weighting 7 to 14 kg were subjected to 60 minutes (min) of severe pressure-targeted controlled hemorrhagic shock (HS) with and without other injuries. After 60 min, resuscitation with 0.9% NaCl and whole blood was initiated. Platelet counts and platelet aggregation assays were performed at baseline (BSLN), end of shock (EOS; T = 60 min), end of resuscitation (EOR; T = 180 min), and T = 360 min on overall cohort. Results are reported as mean ± standard deviation (SD) or median (interquartile range). Statistical analysis was conducted using Spearmen correlation, one-way analysis of variance, two-way repeated-measures analysis of variance, paired t-test or Wilcoxon nonparametric test, with p < 0.05 considered significant. Platelet count in all injury cohorts decreased over time, but no animals developed thrombocytopenia. Correlations were observed between platelet aggregation and platelet count for all agonists: adenosine diphosphate, thrombin recognition-activating peptide-6, collagen, and arachidonic acid. Overall, compared to BSLN, platelet aggregation decreased for all agonist at EOS, EOR, and T = 360 min. When normalized to platelet count, platelet aggregation in response to agonist thrombin recognition-activating peptide-6 demonstrated no change from BSLN at subsequent time points. Aggregation to adenosine diphosphate was significantly less at EOR but not EOS or T = 360 min compared to BSLN. Platelet aggregation to collagen and arachidonic acid was not significantly different at EOS compared to BSLN but was significantly less at EOR and T = 360 min. Nonhuman primates manifest early platelet dysfunction in response to polytraumatic hemorrhagic shock, consistent with that reported in severely injured human patients. Nonhuman primate models potentially are translationally valuable for understanding the mechanisms and pathophysiology of trauma-induced platelet dysfunction.

Surgical benefits of combined awake craniotomy and intraoperative magnetic resonance imaging for gliomas associated with eloquent areas.

PubMed

Motomura, Kazuya; Natsume, Atsushi; Iijima, Kentaro; Kuramitsu, Shunichiro; Fujii, Masazumi; Yamamoto, Takashi; Maesawa, Satoshi; Sugiura, Junko; Wakabayashi, Toshihiko

2017-10-01

OBJECTIVE Maximum extent of resection (EOR) for lower-grade and high-grade gliomas can increase survival rates of patients. However, these infiltrative gliomas are often observed near or within eloquent regions of the brain. Awake surgery is of known benefit for the treatment of gliomas associated with eloquent regions in that brain function can be preserved. On the other hand, intraoperative MRI (iMRI) has been successfully used to maximize the resection of tumors, which can detect small amounts of residual tumors. Therefore, the authors assessed the value of combining awake craniotomy and iMRI for the resection of brain tumors in eloquent areas of the brain. METHODS The authors retrospectively reviewed the records of 33 consecutive patients with glial tumors in the eloquent brain areas who underwent awake surgery using iMRI. Volumetric analysis of MRI studies was performed. The pre-, intra-, and postoperative tumor volumes were measured in all cases using MRI studies obtained before, during, and after tumor resection. RESULTS Intraoperative MRI was performed to check for the presence of residual tumor during awake surgery in a total of 25 patients. Initial iMRI confirmed no further tumor resection in 9 patients (36%) because all observable tumors had already been removed. In contrast, intraoperative confirmation of residual tumor during awake surgery led to further tumor resection in 16 cases (64%) and eventually an EOR of more than 90% in 8 of 16 cases (50%). Furthermore, EOR benefiting from iMRI by more than 15% was found in 7 of 16 cases (43.8%). Interestingly, the increase in EOR as a result of iMRI for tumors associated mainly with the insular lobe was significantly greater, at 15.1%, than it was for the other tumors, which was 8.0% (p = 0.001). CONCLUSIONS This study revealed that combining awake surgery with iMRI was associated with a favorable surgical outcome for intrinsic brain tumors associated with eloquent areas. In particular, these benefits were noted for patients with tumors with complex anatomy, such as those associated with the insular lobe.

Free volume study on the miscibility of PEEK/PEI blend using positron annihilation and dynamic mechanical thermal analysis

NASA Astrophysics Data System (ADS)

Ramani, R.; Alam, S.

2015-06-01

High performance polymer blend of poly(ether ether ketone) (PEEK) and poly(ether imide) (PEI) was examined for their free volume behaviour using positron annihilation lifetime spectroscopy and dynamic mechanical thermal analysis methods. The fractional free volume obtained from PALS shows a negative deviation from linear additivity rule implying good miscibility between PEEK and PEI. The dynamic modulus and loss tangent were obtained for the blends at three different frequencies 1, 10 and 100 Hz at temperatures close to and above their glass transition temperature. Applying Time-Temperature-Superposition (TTS) principle to the DMTA results, master curves were obtained at a reference temperature To and the WLF coefficients c01 and c02 were evaluated. Both the methods give similar results for the dependence of fractional free volume on PEI content in this blend. The results reveal that free volume plays an important role in determining the visco-elastic properties in miscible polymer blends.

Monitoring Conformance and Containment for Geological Carbon Storage: Can Technology Meet Policy and Public Requirements?

NASA Astrophysics Data System (ADS)

Lawton, D. C.; Osadetz, K.

2014-12-01

The Province of Alberta, Canada identified carbon capture and storage (CCS) as a key element of its 2008 Climate Change strategy. The target is a reduction in CO2 emissions of 139 Mt/year by 2050. To encourage uptake of CCS by industry, the province has provided partial funding to two demonstration scale projects, namely the Quest Project by Shell and partners (CCS), and the Alberta Carbon Trunk Line Project (pipeline and CO2-EOR). Important to commercial scale implementation of CCS will be the requirement to prove conformance and containment of the CO2 plume injected during the lifetime of the CCS project. This will be a challenge for monitoring programs. The Containment and Monitoring Institute (CaMI) is developing a Field Research Station (FRS) to calibrate various monitoring technologies for CO2 detection thresholds at relatively shallow depths. The objective being assessed with the FRS is sensitivity for early detection of loss of containment from a deeper CO2 storage project. In this project, two injection wells will be drilled to sandstone reservoir targets at depths of 300 m and 700 m. Up to four observation wells will be drilled with monitoring instruments installed. Time-lapse surface and borehole monitoring surveys will be undertaken to evaluate the movement and fate of the CO2 plume. These will include seismic, microseismic, cross well, electrical resistivity, electromagnetic, gravity, geodetic and geomechanical surveys. Initial baseline seismic data from the FRS will presented.

Structural, Electronic, and Optical Properties of BiOX1-xYx (X, Y = F, Cl, Br, and I) Solid Solutions from DFT Calculations.

PubMed

Zhao, Zong-Yan; Liu, Qing-Lu; Dai, Wen-Wu

2016-08-23

Six BiOX1-xYx (X, Y = F, Cl, Br, and I) solid solutions have been systematically investigated by density functional theory calculations. BiOCl1-xBrx, BiOBr1-xIx, and BiOCl1-xIx solid solutions have very small bowing parameters; as such, some of their properties increase almost linearly with increasing x. For BiOF1-xYx solid solutions, the bowing parameters are very large and it is extremely difficult to fit the related calculated data by a single equation. Consequently, BiOX1-xYx (X, Y = Cl, Br, and I) solid solutions are highly miscible, while BiOF1-xYx (Y = Cl, Br, and I) solid solutions are partially miscible. In other words, BiOF1-xYx solid solutions have miscibility gaps or high miscibility temperature, resulting in phase separation and F/Y inhomogeneity. Comparison and analysis of the calculated results and the related physical-chemical properties with different halogen compositions indicates that the parameters of BiOX1-xYx solid solutions are determined by the differences of the physical-chemical properties of the two halogen compositions. In this way, the large deviation of some BiOX1-xYx solid solutions from Vegard's law observed in experiments can be explained. Moreover, the composition ratio of BiOX1-xYx solid solutions can be measured or monitored using optical measurements.

Small Angle Neutron Scattering Studies on Blends of Poly (Styrene-ran-Vinyl Phenol) with Liquid Crystalline Polyurethane

NASA Astrophysics Data System (ADS)

Mehta, Rujul

2005-03-01

Molecular composites, composed of uniformly dispersed rigid-rod liquid crystalline polymer (LCP) molecules in a flexible amorphous polymer matrix, have remained hitherto elusive due to a scarcity of miscible systems containing a LCP and an amorphous polymer. The production of such a blend, with an experimentally accessible miscibility window, has become possible by modifying the architecture of the flexible polymer, so as to induce favorable intermolecular hydrogen bonding. Specifically, liquid crystalline polyurethanes (LCPU) are found to be miscible with a copolymer of styrene and vinyl phenol; with optimum hydrogen bonding between the carbonyl groups of the urethane linkages and the hydroxyl groups present in the styrenic matrix. Availability of a truly miscible molecular composite presents a unique opportunity of studying the confirmation of polymer chains containing rigid-rods that are uniformly dispersed in a flexible coil matrix. A system consisting of the LCPU and the deuterated styrenic copolymer containing 20% vinyl phenol is examined by Small Angle Neutron Scattering at the National Center for Neutron Research at Gaithersburg and Technology, and the Institute of Solid State Research (IFF) at Jülich. Scattering curves for neat dPS-VPh did not fit the Debye-Bueche model; indicating complex structure. A two correlation length Debye-Bueche model was considered to accommodate for this nonlinear behavior. This model utilizes four fitting parameters, including two correlation lengths a1 and a2, corresponding to a Debye-Bueche model and Guinier model.

Comparison between hot-melt extrusion and spray-drying for manufacturing solid dispersions of the graft copolymer of ethylene glycol and vinylalcohol.

PubMed

Guns, Sandra; Dereymaker, Aswin; Kayaert, Pieterjan; Mathot, Vincent; Martens, Johan A; Van den Mooter, Guy

2011-03-01

To investigate the effect of the manufacturing method (spray-drying or hot-melt extrusion) on the kinetic miscibility of miconazole and the graft copolymer poly(ethyleneglycol-g-vinylalcohol). The effect of heat pre-treatment of solutions used for spray-drying and the use of spray-dried copolymer as excipient for hot-melt extrusion was investigated. The solid dispersions were prepared at different drug-polymer ratios and analyzed with modulated differential scanning calorimetry and X-ray powder diffraction. Miconazole either mixed with the PEG-fraction of the copolymer or crystallized in the same or a different polymorph as the starting material. The kinetic miscibility was higher for the solid dispersions obtained from solutions which were pre-heated compared to those spray-dried from solutions at ambient temperature. Hot-melt extrusion resulted in an even higher mixing capability. Here the use of the spray-dried copolymer did not show any benefit concerning the kinetic miscibility of the drug and copolymer, but it resulted in a remarkable decrease in the torque experienced by the extruder allowing extrusion at lower temperature and torque. The manufacturing method has an influence on the mixing capacity and phase behavior of solid dispersions. Heat pre-treatment of the solutions before spray-drying can result in a higher kinetic miscibility. Amorphization of the copolymer by spray-drying before using it as an excipient for hot-melt extrusion can be a manufacturing benefit.

Offshore Storage Resource Assessment - Final Scientific/Technical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Savage, Bill; Ozgen, Chet

The DOE developed volumetric equation for estimating Prospective Resources (CO 2 storage) in oil and gas reservoirs was utilized on each depleted field in the Federal GOM. This required assessment of the in-situ hydrocarbon fluid volumes for the fields under evaluation in order to apply the DOE equation. This project utilized public data from the U.S. Department of the Interior, Bureau of Ocean Energy Management (BOEM) Reserves database and from a well reputed, large database (250,000+ wells) of GOM well and production data marketed by IHS, Inc. IHS interpreted structure map files were also accessed for a limited number ofmore » fields. The databases were used along with geological and petrophysical software to identify depleted oil and gas fields in the Federal GOM region. BOEM arranged for access by the project team to proprietary reservoir level maps under an NDA. Review of the BOEM’s Reserves database as of December 31, 2013 indicated that 675 fields in the region were depleted. NITEC identified and rank these 675 fields containing 3,514 individual reservoirs based on BOEM’s estimated OOIP or OGIP values available in the Reserves database. The estimated BOEM OOIP or OGIP values for five fields were validated by an independent evaluation using available petrophysical, geologic and engineering data in the databases. Once this validation was successfully completed, the BOEM ranked list was used to calculate the estimated CO 2 storage volume for each field/reservoir using the DOE CO 2 Resource Estimate Equation. This calculation assumed a range for the CO 2 efficiency factor in the equation, as it was not known at that point in time. NITEC then utilize reservoir simulation to further enhance and refine the DOE equation estimated range of CO 2 storage volumes. NITEC used a purpose built, publically available, 4-component, compositional reservoir simulator developed under funding from DOE (DE-FE0006015) to assess CO 2-EOR and CO 2 storage in 73 fields/461 reservoirs. This simulator was fast and easy to utilize and provided a valuable enhanced assessment and refinement of the estimated CO 2 storage volume for each reservoir simulated. The user interface was expanded to allow for calculation of a probability based assessment of the CO 2 storage volume based on typical uncertainties in operating conditions and reservoir properties during the CO 2 injection period. This modeling of the CO 2 storage estimates for the simulated reservoirs resulted in definition of correlations applicable to all reservoir types (a refined DOE equation) which can be used for predictive purposes using available public data. Application of the correlations to the 675 depleted fields yielded a total CO 2 storage capacity of 4,748 MM tons. The CO 2 storage assessments were supplemented with simulation modeling of eleven (11) oil reservoirs that quantified the change in the stored CO 2 storage volume with the addition of CO 2-EOR (Enhanced Oil Recovery) production. Application of CO 2-EOR to oil reservoirs resulted in higher volumes of CO 2 storage.« less

Polymeric nanospheres as a displacement fluid in enhanced oil recovery

NASA Astrophysics Data System (ADS)

Hendraningrat, Luky; Zhang, Julien

2015-12-01

This paper presents the investigation of using nanoscale polyacrylamide-based spheres (nanospheres) as a displacement fluid in enhanced oil recovery (EOR). Coreflood experiments were conducted to evaluate the impact of nanospheres and its concentration dispersed in model formation water on oil recovery during a tertiary oil recovery process. The coreflood results showed that nanospheres can enhance residual oil recovery in the sandstone rock samples and its concentration showed a significant impact into incremental oil. By evaluating the contact angle, it was observed that wettability alteration also might be involved in the possible oil displacement mechanism in this process together with fluid behavior and permeability to water that might divert injected fluid into unswept oil areas and enhance the residual oil recovery. These investigations promote nanospheres aqueous disperse solution as a potential displacement fluid in EOR.

Impact Of Three-Phase Relative Permeability and Hysteresis Models On Forecasts of Storage Associated with CO2-EOR

NASA Astrophysics Data System (ADS)

Jia, W.; Pan, F.; McPherson, B. J. O. L.

2015-12-01

Due to the presence of multiple phases in a given system, CO2 sequestration with enhanced oil recovery (CO2-EOR) includes complex multiphase flow processes compared to CO2 sequestration in deep saline aquifers (no hydrocarbons). Two of the most important factors are three-phase relative permeability and hysteresis effects, both of which are difficult to measure and are usually represented by numerical interpolation models. The purposes of this study included quantification of impacts of different three-phase relative permeability models and hysteresis models on CO2 sequestration simulation results, and associated quantitative estimation of uncertainty. Four three-phase relative permeability models and three hysteresis models were applied to a model of an active CO2-EOR site, the SACROC unit located in western Texas. To eliminate possible bias of deterministic parameters on the evaluation, a sequential Gaussian simulation technique was utilized to generate 50 realizations to describe heterogeneity of porosity and permeability, initially obtained from well logs and seismic survey data. Simulation results of forecasted pressure distributions and CO2 storage suggest that (1) the choice of three-phase relative permeability model and hysteresis model have noticeable impacts on CO2 sequestration simulation results; (2) influences of both factors are observed in all 50 realizations; and (3) the specific choice of hysteresis model appears to be somewhat more important relative to the choice of three-phase relative permeability model in terms of model uncertainty.

Quantifying the potential impact of measurement error in an investigation of autism spectrum disorder (ASD).

PubMed

Heavner, Karyn; Newschaffer, Craig; Hertz-Picciotto, Irva; Bennett, Deborah; Burstyn, Igor

2014-05-01

The Early Autism Risk Longitudinal Investigation (EARLI), an ongoing study of a risk-enriched pregnancy cohort, examines genetic and environmental risk factors for autism spectrum disorders (ASDs). We simulated the potential effects of both measurement error (ME) in exposures and misclassification of ASD-related phenotype (assessed as Autism Observation Scale for Infants (AOSI) scores) on measures of association generated under this study design. We investigated the impact on the power to detect true associations with exposure and the false positive rate (FPR) for a non-causal correlate of exposure (X2, r=0.7) for continuous AOSI score (linear model) versus dichotomised AOSI (logistic regression) when the sample size (n), degree of ME in exposure, and strength of the expected (true) OR (eOR)) between exposure and AOSI varied. Exposure was a continuous variable in all linear models and dichotomised at one SD above the mean in logistic models. Simulations reveal complex patterns and suggest that: (1) There was attenuation of associations that increased with eOR and ME; (2) The FPR was considerable under many scenarios; and (3) The FPR has a complex dependence on the eOR, ME and model choice, but was greater for logistic models. The findings will stimulate work examining cost-effective strategies to reduce the impact of ME in realistic sample sizes and affirm the importance for EARLI of investment in biological samples that help precisely quantify a wide range of environmental exposures.

Polarization leakage in epoch of reionization windows - II. Primary beam model and direction-dependent calibration

NASA Astrophysics Data System (ADS)

Asad, K. M. B.; Koopmans, L. V. E.; Jelić, V.; Ghosh, A.; Abdalla, F. B.; Brentjens, M. A.; de Bruyn, A. G.; Ciardi, B.; Gehlot, B. K.; Iliev, I. T.; Mevius, M.; Pandey, V. N.; Yatawatta, S.; Zaroubi, S.

2016-11-01

Leakage of diffuse polarized emission into Stokes I caused by the polarized primary beam of the instrument might mimic the spectral structure of the 21-cm signal coming from the epoch of reionization (EoR) making their separation difficult. Therefore, understanding polarimetric performance of the antenna is crucial for a successful detection of the EoR signal. Here, we have calculated the accuracy of the nominal model beam of Low Frequency ARray (LOFAR) in predicting the leakage from Stokes I to Q, U by comparing them with the corresponding leakage of compact sources actually observed in the 3C 295 field. We have found that the model beam has errors of ≤10 per cent on the predicted levels of leakage of ˜1 per cent within the field of view, I.e. if the leakage is taken out perfectly using this model the leakage will reduce to 10-3 of the Stokes I flux. If similar levels of accuracy can be obtained in removing leakage from Stokes Q, U to I, we can say, based on the results of our previous paper, that the removal of this leakage using this beam model would ensure that the leakage is well below the expected EoR signal in almost the whole instrumental k-space of the cylindrical power spectrum. We have also shown here that direction-dependent calibration can remove instrumentally polarized compact sources, given an unpolarized sky model, very close to the local noise level.

Optimal level of Au nanoparticles on Pd nanostructures providing remarkable electro-catalysis in direct ethanol fuel cell

NASA Astrophysics Data System (ADS)

Dutta, Abhijit; Mondal, Achintya; Broekmann, Peter; Datta, Jayati

2017-09-01

The designing and fabrication of economically viable electro-catalysts for ethanol oxidation reaction (EOR) in direct ethanol fuel cell (DEFC) has been one of the challenging issues over the decades. The present work deals with controlled synthesis of Pd coupled Au nano structure, as the non Pt group of catalysts for DEFC. The catalytic proficiency of bimetallic NPs (2-10 nm) are found to be strongly dependent on the Pd:Au ratio. The over voltage of EOR is considerably reduced by ∼260 mV with 33% of Au content in PdAu composition compared to Pd alone, demonstrating the beneficial role of Au and/or its surface oxides providing oxygen species at much lower potentials compared to Pd. The catalysts are further subjected to electrochemical analysis through voltammetry along with the temperature study on activation parameters. The quantitative determination of EOR products during the electrolysis is carried out by ion chromatographic analysis; vis-a-vis the coulombic efficiency of the product yield were derived from each of the compositions. Furthermore, a strong correlation among catalytic performances and bimetallic composition is established by screening the catalysts in an in-house fabricated direct ethanol anion exchange membrane fuel cell, DE(AEM)FC. The performance testing demonstrates outstanding increase of peak power density (∼40 mWcm-2, 93%) for the best accomplishment Au (33%) covered Pd (67%) catalyst in comparison with the monometallic Pd.

Double layer effects in electrocatalysis: The oxygen reduction reaction and ethanol oxidation reaction on Au(111), Pt(111) and Ir(111) in alkaline media containing Na and Li cations

DOE PAGES

Lopes, Pietro P.; Strmcnik, Dusan; Jirkovsky, Jakub S.; ...

2015-09-28

Oxygen reduction and ethanol oxidation reactions were studied on Au(111), Pt(111) and Ir(111) in alkaline solutions containing sodium and/or lithium cations. By keeping the same (111) surface orientation and exploring oxophilicity trends and non-covalent interactions between OH ad and alkali metal cations (AMC n+), we were able to gain deep insights into the multiple roles that OH ad plays in these important electrocatalytic reactions. Cyclic voltammetry experiments revealed that OH ad formation initiates at distinct electrode potentials, governed by the oxophilicity of the specific metal surface, with further OH ad adlayer stabilization by non-covalent alkali-cation interactions and affecting the formationmore » of a “true oxide” layer at higher electrode potentials. Although OH ad is a simple spectator for the ORR, it promotes the ethanol oxidation reaction (EOR) at lower potentials and act as spectator at high OHad coverages. By changing the alkali metal cation at the interface (Li +) on more oxophilic surfaces, it was possible to promote the EOR even more, relative to Na +, without changing the product distribution for the reaction. This cation effect suggests that OH ad—Li +(H 2O) x clusters can stabilize the ethoxide adlayer, thus improving the EOR activity. Finally, our results indicate the importance of the entire electrochemical interface in determining the electrocatalytic activity during reaction.« less

Ionic liquids for low-tension oil recovery processes: Phase behavior tests.

PubMed

Rodriguez-Escontrela, Iria; Puerto, Maura C; Miller, Clarence A; Soto, Ana

2017-10-15

Chemical flooding with surfactants for reducing oil-brine interfacial tensions (IFTs) to mobilize residual oil trapped by capillary forces has a great potential for Enhanced Oil Recovery (EOR). Surface-active ionic liquids (SAILs) constitute a class of surfactants that has recently been proposed for this application. For the first time, SAILs or their blends with an anionic surfactant are studied by determining equilibrium phase behavior for systems of about unit water-oil ratio at various temperatures. The test fluids were model alkane and aromatic oils, NaCl brine, and synthetic hard seawater (SW). Patterns of microemulsions observed are those of classical phase behavior (Winsor I-III-II transition) known to correlate with low IFTs. The two anionic room-temperature SAILs tested were made from common anionic surfactants by substituting imidazolium or phosphonium cations for sodium. These two anionic and two cationic SAILs were found to have little potential for EOR when tested individually. Thus, also tested were blends of an anionic internal olefin sulfonate (IOS) surfactant with one of the anionic SAILs and both cationic SAILs. Most promising for EOR was the anionic/cationic surfactant blend of IOS with [C 12 mim]Br in SW. A low equilibrium IFT of ∼2·10 -3 mN/m was measured between n-octane and an aqueous solution having the optimal blend ratio for this system at 25°C. Copyright © 2017 Elsevier Inc. All rights reserved.

An Improved Statistical Point-source Foreground Model for the Epoch of Reionization

NASA Astrophysics Data System (ADS)

Murray, S. G.; Trott, C. M.; Jordan, C. H.

2017-08-01

We present a sophisticated statistical point-source foreground model for low-frequency radio Epoch of Reionization (EoR) experiments using the 21 cm neutral hydrogen emission line. Motivated by our understanding of the low-frequency radio sky, we enhance the realism of two model components compared with existing models: the source count distributions as a function of flux density and spatial position (source clustering), extending current formalisms for the foreground covariance of 2D power-spectral modes in 21 cm EoR experiments. The former we generalize to an arbitrarily broken power law, and the latter to an arbitrary isotropically correlated field. This paper presents expressions for the modified covariance under these extensions, and shows that for a more realistic source spatial distribution, extra covariance arises in the EoR window that was previously unaccounted for. Failure to include this contribution can yield bias in the final power-spectrum and under-estimate uncertainties, potentially leading to a false detection of signal. The extent of this effect is uncertain, owing to ignorance of physical model parameters, but we show that it is dependent on the relative abundance of faint sources, to the effect that our extension will become more important for future deep surveys. Finally, we show that under some parameter choices, ignoring source clustering can lead to false detections on large scales, due to both the induced bias and an artificial reduction in the estimated measurement uncertainty.

SUBTASK 2.19 – OPERATIONAL FLEXIBILITY OF CO2 TRANSPORT AND STORAGE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jensen, Melanie; Schlasner, Steven; Sorensen, James

2014-12-31

Carbon dioxide (CO2) is produced in large quantities during electricity generation and by industrial processes. These CO2 streams vary in terms of both composition and mass flow rate, sometimes substantially. The impact of a varying CO2 stream on pipeline and storage operation is not fully understood in terms of either operability or infrastructure robustness. This study was performed to summarize basic background from the literature on the topic of operational flexibility of CO2 transport and storage, but the primary focus was on compiling real-world lessons learned about flexible operation of CO2 pipelines and storage from both large-scale field demonstrations andmore » commercial operating experience. Modeling and pilot-scale results of research in this area were included to illustrate some of the questions that exist relative to operation of carbon capture and storage (CCS) projects with variable CO2 streams. It is hoped that this report’s real-world findings provide readers with useful information on the topic of transport and storage of variable CO2 streams. The real-world results were obtained from two sources. The first source consisted of five full-scale, commercial transport–storage projects: Sleipner, Snøhvit, In Salah, Weyburn, and Illinois Basin–Decatur. These scenarios were reviewed to determine the information that is available about CO2 stream variability/intermittency on these demonstration-scale projects. The five projects all experienced mass flow variability or an interruption in flow. In each case, pipeline and/or injection engineers were able to accommodate any issues that arose. Significant variability in composition has not been an issue at these five sites. The second source of real- world results was telephone interviews conducted with experts in CO2 pipeline transport, injection, and storage during which commercial anecdotal information was acquired to augment that found during the literature search of the five full-scale projects. The experts represented a range of disciplines and hailed from North America and Europe. Major findings of the study are that compression and transport of CO2 for enhanced oil recovery (EOR) purposes in the United States has shown that impurities are not likely to cause transport problems if CO2 stream composition standards are maintained and pressures are kept at 10.3 MPa or higher. Cyclic, or otherwise intermittent, CO2 supplies historically have not impacted in-field distribution pipeline networks, wellbore integrity, or reservoir conditions. The U.S. EOR industry has demonstrated that it is possible to adapt to variability and intermittency in CO2 supply through flexible operation of the pipeline and geologic storage facility. This CO2 transport and injection experience represents knowledge that can be applied in future CCS projects. A number of gaps in knowledge were identified that may benefit from future research and development, further enhancing the possibility for widespread application of CCS. This project was funded through the Energy & Environmental Research Center–U.S. Department of Energy Joint Program on Research and Development for Fossil Energy-Related Resources Cooperative Agreement No. DE-FC26-08NT43291. Nonfederal funding was provided by the IEA Greenhouse Gas R&D Programme.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doug Cathro

The Lake Charles CCS Project is a large-scale industrial carbon capture and sequestration (CCS) project which will demonstrate advanced technologies that capture and sequester carbon dioxide (CO{sub 2}) emissions from industrial sources into underground formations. Specifically the Lake Charles CCS Project will accelerate commercialization of large-scale CO{sub 2} storage from industrial sources by leveraging synergy between a proposed petroleum coke to chemicals plant (the LCC Gasification Project) and the largest integrated anthropogenic CO{sub 2} capture, transport, and monitored sequestration program in the U.S. Gulf Coast Region. The Lake Charles CCS Project will promote the expansion of EOR in Texas andmore » Louisiana and supply greater energy security by expanding domestic energy supplies. The capture, compression, pipeline, injection, and monitoring infrastructure will continue to sequester CO{sub 2} for many years after the completion of the term of the DOE agreement. The objectives of this project are expected to be fulfilled by working through two distinct phases. The overall objective of Phase 1 was to develop a fully definitive project basis for a competitive Renewal Application process to proceed into Phase 2 - Design, Construction and Operations. Phase 1 includes the studies attached hereto that will establish: the engineering design basis for the capture, compression and transportation of CO{sub 2} from the LCC Gasification Project, and the criteria and specifications for a monitoring, verification and accounting (MVA) plan at the Hastings oil field in Texas. The overall objective of Phase 2, provided a successful competitive down-selection, is to execute design, construction and operations of three capital projects: (1) the CO{sub 2} capture and compression equipment, (2) a Connector Pipeline from the LLC Gasification Project to the Green Pipeline owned by Denbury and an affiliate of Denbury, and (3) a comprehensive MVA system at the Hastings oil field.« less

Texas Clean Energy Project: Topical Report, Phase 1 - February 2010-December 2012

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mattes, Karl

2012-11-01

Summit Texas Clean Energy, LLC (STCE) is developing the Texas Clean Energy Project (TCEP or the project) to be located near Penwell, Texas. The TCEP will include an Integrated Gasification Combined Cycle (IGCC) plant with a nameplate capacity of 400 megawatts electric (MWe), combined with the production of urea fertilizer and the capture, utilization and storage of carbon dioxide (CO 2) sold commercially for regional use in enhanced oil recovery (EOR) in the Permian Basin of west Texas. The TCEP will utilize coal gasification technology to convert Powder River Basin subbituminous coal delivered by rail from Wyoming into a syntheticmore » gas (syngas) which will be cleaned and further treated so that at least 90 percent of the overall carbon entering the facility will be captured. The clean syngas will then be divided into two high-hydrogen (H 2) concentration streams, one of which will be combusted as a fuel in a combined cycle power block for power generation and the other converted into urea fertilizer for commercial sale. The captured CO 2 will be divided into two streams: one will be used in producing the urea fertilizer and the other will be compressed for transport by pipeline for offsite use in EOR and permanent underground sequestration. The TCEP was selected by the U.S. Department of Energy (DOE) Office of Fossil Energy (FE) for cost-shared co-funded financial assistance under Round 3 of its Clean Coal Power Initiative (CCPI). A portion of this financial assistance was budgeted and provided for initial development, permitting and design activities. STCE and the DOE executed a Cooperative Agreement dated January 29, 2010, which defined the objectives of the project for all phases. During Phase 1, STCE conducted and completed all objectives defined in the initial development, permitting and design portions of the Cooperative Agreement. This topical report summarizes all work associated with the project objectives, and additional work required to complete the financing of the project. In general, STCE completed project definition, a front-end, engineering and design study (FEED), applied for and received its Record of Decision (ROD) associated with the NEPA requirements summarized in a detailed Environmental Impact Statement. A topical report covering the results of the FEED is the subject of a separate report submitted to the DOE on January 26, 2012. References to the FEED report are contained herein. In December 2011, STCE executed fixed-price turnkey EPC contracts and a long-term O&M agreement with industry-leading contractors.. Other work completed during Phase 1 includes execution of all major commercial input and offtake agreements. STCE negotiated long-term agreements for power, CO 2 and urea offtake. A contract for the purchase of coal feedstock from Cloud Peak Energy’s Cordero Rojo mine was executed, as well as a memorandum of understanding with the Union Pacific Railroad (UPRR) for delivery of the coal to the TCEP site. An MOU for natural gas supply was completed with ONEOK, and a long-term water supply agreement was completed with a private landowner. In addition, STCE secured options for easements and rights-of-way, completed a transmission study, executed an interconnection agreement and devoted substantial effort to debt and conventional and tax equity structuring to position the Project for project financing, currently scheduled for closing on December 31, 2012.« less

Entanglement in miscible blends

NASA Astrophysics Data System (ADS)

Watanabe, Hiroshi

2010-03-01

The entanglement length Le of polymer chains (corresponding to the entanglement molecular weight Me) is not an intrinsic material parameter but changes with the interaction with surrounding chains. For miscible blends of cis-polyisoprene (PI) and poly(tert-butyl styrene) (PtBS), changes of Le on blending was examined. It turned out that the Le averaged over the number fractions of the Kuhn segments of the components (PI and PtBS) satisfactorily describes the viscoelastic behavior of pseudo-monodisperse blends in which the terminal relaxation time is the same for PI and PtBS.

Evidence of a miscibility gap in the FeTe1-xSex polycrystalline samples prepared with a melting process

NASA Astrophysics Data System (ADS)

Sala, A.; Palenzona, A.; Bernini, C.; Caglieris, F.; Cimberle, M. R.; Ferdeghini, C.; Lamura, G.; Martinelli, A.; Pani, M.; Hecher, J.; Eisterer, M.; Putti, M.

2014-05-01

The study of overdoped FeTe1-xSex (0.5 < x < 1) polycrystalline superconductor samples is reported. The samples were prepared using a melting technique previously developed by our group. Increasing the Se content a phase separation related to the formation of FeSe inside the Fe(Se,Te) phase happens, as demonstrated by structural analysis and magnetic characterization. The proposed phase separation picture is likely the fingerprint of a miscibility gap in the Fe(Se,Te) system.

Final Research Performance Report - Small Molecular Associative Carbon Dioxide (CO 2) Thickeners for Improved Mobility Control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Enick, Robert M.

The initial objective of this project was to promote the application of a CO 2 thickener for improved mobility control during CO 2 EOR based on solubility tests, viscosity tests, and core floods. Ultimately, it was demonstrated that the CO 2-soluble polymeric thickeners are much better suited for use a CO 2-soluble conformance control agents for diverting the flow of CO 2 away from thief zones. Our team generated several effective small molecule CO 2 thickeners with ARPA-e funding. Unfortunately, none of these small molecule thickeners could dissolve in CO 2 without the addition of unacceptably large amounts of hexanemore » or toluene as a co-solvent Therefore none were viable candidates for the core flooding studies associated with NETL award. Therefore during the entire core flood testing program associated with this NETL award, our team used only the most promising polymeric CO 2 thickener, a polyfluoroacrylate (PFA). In order to produce an environmentally benign polymer, the monomer used to make the new polymers used in this study was a fluoroacrylate that contains only six fluorinated carbons. We verified CO 2 solubility with a phase behavior cell. The thickening potential of all polymer samples was substantiated with a falling ball viscometer and a falling cylinder viscometer at Pitt. Two different viscometers were used to determine the increase in CO 2 viscosity that could be achieved via the dissolution of PFA. Praxair, which has an interest in thickening CO 2 for pilot EOR projects and for waterless hydraulic fracturing, agreed to measure the viscosity of CO 2-PFA solutions at no cost to the project. Falling cylinder viscometery was conducted at Pitt in our windowed high pressure phase behavior cell. Both apparatuses indicated that at very low shear rates the CO 2 viscosity increased by a factor of roughly 3.5 when 1wt% PFA was dissolved in the CO 22. Our team also planned thickener concentrations and compositions at Pitt for the core tests that were conducted at Special Core Analysis Laboratories, Inc., (SCAL) in Midland, TX, where the ability for PFA to reduce CO 2 mobility in a core was then tested. During the beginning of these tests, the PFA polymer was then shown to impart reasonable improvements in mobility control during the SCAL core tests; as the CO 2-PFA solution displaced CO 2 from the core at a constant volumetric flow rate, the pressure drop increased as expected. However, as the test progressed, there was clear and surprising evidence of dramatic reductions in core permeability due to PFA adsorption, especially for sandstones. For example, as the CO 2-PFA solution displaced pure CO 2 from sandstone and limestone cores, the pressure drop increased by factors of multiple hundreds to over a thousand. It was subsequently demonstrated that the PFA injected into the core either (a) adsorbed strongly and irreversibly onto the rock surfaces, (b) deposited/precipitated within the rock, thereby blocking pores in a manner that could be dislodged by large changes in flow rate or flow direction, or (c) remained in solution and passed completely through the core. The loss of PFA to the porous media and the unacceptably large increases in pressure drop both indicated that PFA was inappropriate for CO 2 EOR mobility control, where thickener adsorption must be minimized and mobility reductions of only 10-100-fold are typically required. However, we realized that because the CO 2-PFA solution could greatly reduce the permeability of porous media, it could serve as a near wellbore conformance control agent for blocking “thief zones”, where adsorption is acceptable and dramatic increases in pressure drop are desirable. These effects were more dramatic for sandstone than for limestone. Therefore, these PFA fluoroacrylate polymers can serve as a CO 2-soluble conformance control agent for CO 2-EOR, especially in sandstone formations. This injection of a single phase solution of CO 2-PFA for permeability reduction is (to the best of our knowledge) the first report of a CO 2-soluble conformance control additive. We also demonstrated that the optimal strategy for using CO 2-PFA solutions for conformance control is analogous to the application of water-based polymeric gels; the CO 2-PFA solution should first be injected only in an isolated thief zone to induce dramatic reductions in permeability only in that thief zone, and then CO 2 should be injected into all of the zones. Finally, it was noted that given the propensity of PFA to adsorb onto sandstone, the adsorption of PFA from CO 2-PFA solutions onto cement surfaces promote the sealing of extremely fine cracks in casing cement.« less

CO/sub 2/ line design needs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Recht, D.L.

Large volumes of carbon dioxide are required for tertiary oil recovery projects that utilize the carbon dioxide miscible flooding method. Carbon dioxide can be successfully transported as a supercritical fluid through a pipeline designed and operated similar to a natural gas pipeline, with careful consideration given to specific differences in design and materials of construction. Carbon dioxide is a colorless, odorless, nonflammable, non-toxic substance that may exist as a gas, as a liquid, as a solid, or in all three forms at its triple point. The critical pressure and temperature of CO/sub 2/ are 1,070 psia and 88/sup 0/F, respectively.more » It is present in the normal atmosphere in a concentration of approximately 330 ppm, and somewhat higher concentrations may occur in occupied buildings. Air in lungs contains approximately 5.5% (55,000 ppm) of CO/sub 2/. Although it is non-toxic, air containing 10% to 20% CO/sub 2/ concentrations by volume is immediately hazardous to life by causing unconsciousness, failure of respiratory muscles, and a change in the pH of the blood stream. Carbon dioxide is commonly used for carbonated beverages, aerosol propellants, fire extinguishers, enrichment of air in greenhouses, fracturing and acidizing of oil wells, as a shielding gas for welding, and as dry ice for refrigeration. In tertiary recovery projects of suitable oil reservoirs, CO/sub 2/ is injected into the formation where it dissolves in the oil, swells the oil, reduces the oil's viscosity, exerts an acidic effect on the reservoir rock (in some cases), and vaporizes some of the oil. As a rough rule of thumb, approximately 6 to 10 mcf of CO/sub 2/ are required to be injected for recovery of 1 bbl of oil. Carbon dioxide miscible flooding will recover approximately 10% to 15% of the oil remaining in place after a waterflood program.« less

The effects of forced small-wavelength, finite-bandwidth initial perturbations and miscibility on the turbulent Rayleigh–Taylor instability

DOE PAGES

Roberts, M. S.; Jacobs, J. W.

2015-12-07

Rayleigh–Taylor instability experiments are performed using both immiscible and miscible incompressible liquid combinations having a relatively large Atwood number ofmore » $$A\\equiv ({\\it\\rho}_{2}-{\\it\\rho}_{1})/({\\it\\rho}_{2}+{\\it\\rho}_{1})=0.48$$. The liquid-filled tank is attached to a test sled that is accelerated downwards along a vertical rail system using a system of weights and pulleys producing approximately$1g$$net acceleration. The tank is backlit and images are digitally recorded using a high-speed video camera. The experiments are either initiated with forced initial perturbations or are left unforced. The forced experiments have an initial perturbation imposed by vertically oscillating the liquid-filled tank to produce Faraday waves at the interface. The unforced experiments rely on random interfacial fluctuations, resulting from background noise, to seed the instability. The main focus of this study is to determine the effects of forced initial perturbations and the effects of miscibility on the growth parameter,$${\\it\\alpha}$$. Measurements of the mixing-layer width,$$h$$, are acquired, from which$${\\it\\alpha}$$is determined. It is found that initial perturbations of the form used in this study do not affect measured$${\\it\\alpha}$$values. However, miscibility is observed to strongly affect$${\\it\\alpha}$$, resulting in a factor of two reduction in its value, a finding not previously observed in past experiments. In addition, all measured$${\\it\\alpha}$values are found to be smaller than those obtained in previous experimental studies.« less

Live cell plasma membranes do not exhibit a miscibility phase transition over a wide range of temperatures.

PubMed

Lee, Il-Hyung; Saha, Suvrajit; Polley, Anirban; Huang, Hector; Mayor, Satyajit; Rao, Madan; Groves, Jay T

2015-03-26

Lipid/cholesterol mixtures derived from cell membranes as well as their synthetic reconstitutions exhibit well-defined miscibility phase transitions and critical phenomena near physiological temperatures. This suggests that lipid/cholesterol-mediated phase separation plays a role in the organization of live cell membranes. However, macroscopic lipid-phase separation is not generally observed in cell membranes, and the degree to which properties of isolated lipid mixtures are preserved in the cell membrane remain unknown. A fundamental property of phase transitions is that the variation of tagged particle diffusion with temperature exhibits an abrupt change as the system passes through the transition, even when the two phases are distributed in a nanometer-scale emulsion. We support this using a variety of Monte Carlo and atomistic simulations on model lipid membrane systems. However, temperature-dependent fluorescence correlation spectroscopy of labeled lipids and membrane-anchored proteins in live cell membranes shows a consistently smooth increase in the diffusion coefficient as a function of temperature. We find no evidence of a discrete miscibility phase transition throughout a wide range of temperatures: 14-37 °C. This contrasts the behavior of giant plasma membrane vesicles (GPMVs) blebbed from the same cells, which do exhibit phase transitions and macroscopic phase separation. Fluorescence lifetime analysis of a DiI probe in both cases reveals a significant environmental difference between the live cell and the GPMV. Taken together, these data suggest the live cell membrane may avoid the miscibility phase transition inherent to its lipid constituents by actively regulating physical parameters, such as tension, in the membrane.

Modelling of Seismic and Resistivity Responses during the Injection of CO2 in Sandstone Reservoir

NASA Astrophysics Data System (ADS)

Omar, Muhamad Nizarul Idhafi Bin; Almanna Lubis, Luluan; Nur Arif Zanuri, Muhammad; Ghosh, Deva P.; Irawan, Sonny; Regassa Jufar, Shiferaw

2016-07-01

Enhanced oil recovery plays vital role in production phase in a producing oil field. Initially, in many cases hydrocarbon will naturally flow to the well as respect to the reservoir pressure. But over time, hydrocarbon flow to the well will decrease as the pressure decrease and require recovery method so called enhanced oil recovery (EOR) to recover the hydrocarbon flow. Generally, EOR works by injecting substances, such as carbon dioxide (CO2) to form a pressure difference to establish a constant productive flow of hydrocarbon to production well. Monitoring CO2 performance is crucial in ensuring the right trajectory and pressure differences are established to make sure the technique works in recovering hydrocarbon flow. In this paper, we work on computer simulation method in monitoring CO2 performance by seismic and resistivity model, enabling geoscientists and reservoir engineers to monitor production behaviour as respect to CO2 injection.

SKN-1-independent transcriptional activation of glutathione S-transferase 4 (GST-4) by EGF signaling

PubMed Central

Van de Walle, Pieter; Schoofs, Liliane

2016-01-01

ABSTRACT In C. elegans research, transcriptional activation of glutathione S-transferase 4 (gst-4) is often used as a read-out for SKN-1 activity. While many heed an assumed non-exclusivity of the GFP reporter signal driven by the gst-4 promoter to SKN-1, this is also often ignored. We here show that gst-4 can also be transcriptionally activated by EOR-1, a transcription factor mediating effects of the epidermal growth factor (EGF) pathway. Along with enhancing exogenous oxidative stress tolerance, EOR-1 inde-pendently of SKN-1 increases gst-4 transcription in response to augmented EGF signaling. Our findings caution researchers within the C. elegans community to always rely on sufficient experimental controls when assaying SKN-1 transcriptional activity with a gst-4p::gfp reporter, such as SKN-1 loss-of-function mutants and/or additional target genes next to gst-4. PMID:28090393

Constraining the CMB optical depth through the dispersion measure of cosmological radio transients

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fialkov, A.; Loeb, A., E-mail: anastasia.fialkov@cfa.harvard.edu, E-mail: aloeb@cfa.harvard.edu

2016-05-01

The dispersion measure of extragalactic radio transients can be used to measure the column density of free electrons in the intergalactic medium. The same electrons also scatter the Cosmic Microwave Background (CMB) photons, affecting precision measurements of cosmological parameters. We explore the connection between the dispersion measure of radio transients existing during the Epoch of Reionization (EoR) and the total optical depth for the CMB showing that the existence of such transients would provide a new sensitive probe of the CMB optical depth. As an example, we consider the population of FRBs. Assuming they exist during the EoR, we showmore » that: (i) such sources can probe the reionization history by measuring the optical depth to sub-percent accuracy, and (ii) they can be detected with high significance by an instrument such as the Square Kilometer Array.« less

Assessing the Strength Enhancement of Heterogeneous Networks of Miscible Polymer Blends

NASA Astrophysics Data System (ADS)

Giller, Carl; Roland, Mike

2013-03-01

At the typical crosslink densities of elastomers, the failure properties vary inversely with mechanical stiffness, so that compounding entails a compromise between stiffness and strength. Our approach to circumvent this conventional limitation is by forming networks of two polymers that: (i) are thermodynamically miscible, whereby the chemical composition is uniform on the segmental level; and (ii) have markedly different reactivities for network formation. The resulting elastomer consists of one highly crosslinked component and one that is lightly or uncrosslinked. This disparity in crosslinking causes their respective contributions to the network mechanical response to differ diametrically. Earlier results showed some success with this approach for thermally crosslinked blends of 1,2-polybutadiene (PVE) and polyisoprene (PI), as well as ethylene-propylene copolymer (EPM) and ethylene-propylene-diene random terpolymer (EPDM), taking advantage of their differing reactivities to sulfur. In this work we demonstrate the miscibility of polyisobutylene (PIB) with butyl rubber (BR) (a copolymer of PIB and polyisoprene) and show that networks in which only the BR is crosslinked possess greater tensile strengths than neat BR over the same range of moduli. Office of Naval Research

A test-tube model for rainfall

NASA Astrophysics Data System (ADS)

Wilkinson, Michael

2014-05-01

If the temperature of a cell containing two partially miscible liquids is changed very slowly, so that the miscibility is decreased, microscopic droplets nucleate, grow and migrate to the interface due to their buoyancy. The system may show an approximately periodic variation of the turbidity of the mixture, as the mean droplet size fluctuates. These precipitation events are analogous to rainfall. This paper considers a theoretical model for these experiments. After nucleation the initial growth is by Ostwald ripening, followed by a finite-time runaway growth of droplet sizes due to larger droplets sweeping up smaller ones. The model predicts that the period \\Delta t and the temperature sweep rate ξ are related by \\Delta t\\sim C \\xi^{-3/7} , and is in good agreement with experiments. The coefficient C has a power-law divergence approaching the critical point of the miscibility transition: C\\sim (T-T_{\\text{c}})^{-\\eta} , and the critical exponent η is determined. It is argued that while the mechanism does not provide a quantitative description of terrestrial rainfall, it may be a faithful model for precipitation on other planets.

Viscometric investigation of compatibilization of the poly(vinyl chloride)/poly(ethylene-co-vinyl acetate) blends by terpolymer of maleic anhydride styrene vinyl acetate

NASA Astrophysics Data System (ADS)

İmren, Dilek; Boztuğ, Ali; Yılmaz, Ersen; Zengin, H. Bayram

2008-11-01

In this study, a blend of poly(vinyl chloride) (PVC)/ethylene-co-vinyl acetate (EVA) was compatibilized by terpolymer of maleic anhydride-styrene-vinyl acetate (MAStVA) used as a compatibilizer. It was prepared the blends of 50/50 PVC/EVA containing 2-10% of the terpolymer. The compatibility experiences of these blends were investigated by using viscometric method in the range of concentrations (0.5-2.0 g dL -1) where tetrahydrofuran (THF) is the solvent. The interaction parameter (Δ b) was used to study the miscibility and compatibility of polymer blend in solution, obtained from the modified Krigbaum and Wall theory. Turbidity and FTIR measurements were also used to investigate the miscibility of this pair of polymers. The values of the relative viscosities of the each polymer solution and their blends were measured by a Cannon-Fenske type viscometer. In consequence of the study, it was observed that a considerable improvement was achieved in the miscibility of PVC/EVA blends by adding among 5 and 10 wt% of compatibilizer.

Miscibility of binary monolayers at the air-water interface and interaction of protein with immobilized monolayers by surface plasmon resonance technique.

PubMed

Wang, Yuchun; Du, Xuezhong

2006-07-04

The miscibility and stability of the binary monolayers of zwitterionic dipalmitoylphosphatidylcholine (DPPC) and cationic dioctadecyldimethylammonium bromide (DOMA) at the air-water interface and the interaction of ferritin with the immobilized monolayers have been studied in detail using surface pressure-area isotherms and surface plasmon resonance technique, respectively. The surface pressure-area isotherms indicated that the binary monolayers of DPPC and DOMA at the air-water interface were miscible and more stable than the monolayers of the two individual components. The surface plasmon resonance studies indicated that ferritin binding to the immobilized monolayers was primarily driven by the electrostatic interaction and that the amount of adsorbed protein at saturation was closely related not only to the number of positive charges in the monolayers but also to the pattern of positive charges at a given mole fraction of DOMA. The protein adsorption kinetics was determined by the properties of the monolayers (i.e., the protein-monolayer interaction) and the structure of preadsorbed protein molecules (i.e., the protein-protein interaction).

Characterization of Physical and Mechanical Properties of Miscible Lactose-Sugars Systems.

PubMed

Li, Runjing; Roos, Yrjö H; Miao, Song

2017-09-01

Lactose-sugars systems were produced by spray drying. They were lactose, lactose-glucose (4:1) mixtures, lactose-maltose (4:1) mixtures, lactose-sucrose (4:1) mixtures, lactose-trehalose (4:1) mixtures, and lactose-corn syrup solids (CSS) (4:1) mixtures. The physical characteristics, water sorption behavior, glass transition, and mechanical properties of miscible lactose-sugars systems were investigated. Lactose-glucose mixtures had larger particle size than other lactose-sugars systems after spray drying. The presence of glucose or sucrose in lactose-sugars mixtures decreased the glass transition temperatures of amorphous systems, while the presence of maltose and trehalose had only minor impact on the glass transition temperatures. Moreover, glucose accelerated the crystallization of amorphous system at 0.44 a w , but its presence delayed the loss of sorbed water at higher water activities (≥0.54 a w ). Mechanical property study indicated that glucose and sucrose in amorphous system could result in an increase of molecular mobility, while the presence of CSS could decrease the free volume and maintain the stiffness of the miscible systems. © 2017 Institute of Food Technologists®.

Texas Clean Energy Project: Decision Point Application, Section 2: Topical Report - Phase 1, February 2010-October 2013

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mattes, Karl

Summit Texas Clean Energy, LLC (STCE) is developing the Texas Clean Energy Project (TCEP or the Project) to be located near Penwell, Texas. The TCEP will include an Integrated Gasification Combined Cycle (IGCC) power plant with a nameplate capacity of 400 megawatts electric (MWe), combined with the production of urea fertilizer and the capture, utilization and storage of carbon dioxide (CO 2) sold commercially for regional use in enhanced oil recovery (EOR) in the Permian Basin of west Texas. The TCEP will utilize coal gasification technology to convert Powder River Basin subbituminous coal delivered by rail from Wyoming into amore » synthetic gas (syngas) that will be cleaned and further treated so that at least 90 percent of the overall carbon entering the IGCC facility will be captured. The clean syngas will then be divided into two highhydrogen (H 2) concentration streams, one of which will be combusted as a fuel in a combined cycle power block for power generation and the other converted into urea fertilizer for commercial sale. The captured CO 2 will be divided into two streams: one will be used in producing the urea fertilizer and the other will be compressed for transport by pipeline for offsite use in EOR and permanent underground sequestration. The TCEP was selected by the U.S. Department of Energy (DOE) Office of Fossil Energy (FE) for cost-shared co-funded financial assistance under Round 3 of its Clean Coal Power Initiative (CCPI). A portion of this financial assistance was budgeted and provided for initial development, permitting and design activities. STCE and the DOE executed a Cooperative Agreement dated January 29, 2010, which defined the objectives of the Project for all phases. During Phase 1, STCE conducted and completed all objectives defined in the initial development, permitting and design portions of the Cooperative Agreement. This topical report summarizes all work associated with the project objectives, and additional work required to complete the financing of the Project. In general, STCE completed project definition, a front-end, engineering and design study (FEED), applied for and received its Record of Decision (ROD) associated with the NEPA requirements summarized in a detailed Environmental Impact Statement. A topical report covering the results of the FEED is the subject of a separate report submitted to the DOE on January 26, 2012. References to the FEED report are contained herein. In August 2013, STCE executed fixed-price turnkey EPC contracts and previously, in December 2011 a long-term O&M agreement, with industry-leading contractors. Other work completed during Phase 1 includes execution of all commercial input and offtake agreements required for project financing. STCE negotiated long-term agreements for power, CO 2 and urea offtake. A contract for the purchase of coal feedstock from Cloud Peak Energy’s Cordero Rojo mine was executed, as well as necessary agreements (supplementing the tariff) with the Union Pacific Railroad (UPRR) for delivery of the coal to the TCEP site. STCE executed firm agreements for natural gas transportation with ONEOK for long-term water supply with a private landowner. In addition, STCE secured options for critical easements and rights-of-way, completed and updated a transmission study, executed an interconnection agreement and has agreed a target October 31, 2013 financial closing date with debt and conventional and tax equity.« less

Quantifying the non-Gaussianity in the EoR 21-cm signal through bispectrum

NASA Astrophysics Data System (ADS)

Majumdar, Suman; Pritchard, Jonathan R.; Mondal, Rajesh; Watkinson, Catherine A.; Bharadwaj, Somnath; Mellema, Garrelt

2018-05-01

The epoch of reionization (EoR) 21-cm signal is expected to be highly non-Gaussian in nature and this non-Gaussianity is also expected to evolve with the progressing state of reionization. Therefore the signal will be correlated between different Fourier modes (k). The power spectrum will not be able capture this correlation in the signal. We use a higher order estimator - the bispectrum - to quantify this evolving non-Gaussianity. We study the bispectrum using an ensemble of simulated 21-cm signal and with a large variety of k triangles. We observe two competing sources driving the non-Gaussianity in the signal: fluctuations in the neutral fraction (x_{H I}) field and fluctuations in the matter density field. We find that the non-Gaussian contribution from these two sources varies, depending on the stage of reionization and on which k modes are being studied. We show that the sign of the bispectrum works as a unique marker to identify which among these two components is driving the non-Gaussianity. We propose that the sign change in the bispectrum, when plotted as a function of triangle configuration cos θ and at a certain stage of the EoR can be used as a confirmative test for the detection of the 21-cm signal. We also propose a new consolidated way to visualize the signal evolution (with evolving \\bar{x}_{H I} or redshift), through the trajectories of the signal in a power spectrum and equilateral bispectrum i.e. P(k) - B(k, k, k) space.

Deconvolving the wedge: maximum-likelihood power spectra via spherical-wave visibility modelling

NASA Astrophysics Data System (ADS)

Ghosh, A.; Mertens, F. G.; Koopmans, L. V. E.

2018-03-01

Direct detection of the Epoch of Reionization (EoR) via the red-shifted 21-cm line will have unprecedented implications on the study of structure formation in the infant Universe. To fulfil this promise, current and future 21-cm experiments need to detect this weak EoR signal in the presence of foregrounds that are several orders of magnitude larger. This requires extreme noise control and improved wide-field high dynamic-range imaging techniques. We propose a new imaging method based on a maximum likelihood framework which solves for the interferometric equation directly on the sphere, or equivalently in the uvw-domain. The method uses the one-to-one relation between spherical waves and spherical harmonics (SpH). It consistently handles signals from the entire sky, and does not require a w-term correction. The SpH coefficients represent the sky-brightness distribution and the visibilities in the uvw-domain, and provide a direct estimate of the spatial power spectrum. Using these spectrally smooth SpH coefficients, bright foregrounds can be removed from the signal, including their side-lobe noise, which is one of the limiting factors in high dynamics-range wide-field imaging. Chromatic effects causing the so-called `wedge' are effectively eliminated (i.e. deconvolved) in the cylindrical (k⊥, k∥) power spectrum, compared to a power spectrum computed directly from the images of the foreground visibilities where the wedge is clearly present. We illustrate our method using simulated Low-Frequency Array observations, finding an excellent reconstruction of the input EoR signal with minimal bias.

Electrochemical Behavior of TiO(x)C(y) as Catalyst Support for Direct Ethanol Fuel Cells at Intermediate Temperature: From Planar Systems to Powders.

PubMed

Calvillo, Laura; García, Gonzalo; Paduano, Andrea; Guillen-Villafuerte, Olmedo; Valero-Vidal, Carlos; Vittadini, Andrea; Bellini, Marco; Lavacchi, Alessandro; Agnoli, Stefano; Martucci, Alessandro; Kunze-Liebhäuser, Julia; Pastor, Elena; Granozzi, Gaetano

2016-01-13

To achieve complete oxidation of ethanol (EOR) to CO2, higher operating temperatures (often called intermediate-T, 150-200 °C) and appropriate catalysts are required. We examine here titanium oxycarbide (hereafter TiOxCy) as a possible alternative to standard carbon-based supports to enhance the stability of the catalyst/support assembly at intermediate-T. To test this material as electrocatalyst support, a systematic study of its behavior under electrochemical conditions was carried out. To have a clear description of the chemical changes of TiOxCy induced by electrochemical polarization of the material, a special setup that allows the combination of X-ray photoelectron spectroscopy and electrochemical measurements was used. Subsequently, an electrochemical study was carried out on TiOxCy powders, both at room temperature and at 150 °C. The present study has revealed that TiOxCy is a sufficiently conductive material whose surface is passivated by a TiO2 film under working conditions, which prevents the full oxidation of the TiOxCy and can thus be considered a stable electrode material for EOR working conditions. This result has also been confirmed through density functional theory (DFT) calculations on a simplified model system. Furthermore, it has been experimentally observed that ethanol molecules adsorb on the TiOxCy surface, inhibiting its oxidation. This result has been confirmed by using in situ Fourier transform infrared spectroscopy (FTIRS). The adsorption of ethanol is expected to favor the EOR in the presence of suitable catalyst nanoparticles supported on TiOxCy.

Endoplasmic Reticulum Stress Response and Mutant Protein Degradation in CHO Cells Accumulating Antithrombin (C95R) in Russell Bodies.

PubMed

Kimura, Koji; Inoue, Kengo; Okubo, Jun; Ueda, Yumiko; Kawaguchi, Kosuke; Sakurai, Hiroaki; Wada, Ikuo; Morita, Masashi; Imanaka, Tsuneo

2015-01-01

Newly synthesized secretory proteins are folded and assembled in the endoplasmic reticulum (ER), where an efficient protein quality control system performs a critically important function. When unfolded or aggregated proteins accumulate in the ER, certain signaling pathways such as the unfolded protein response (UPR) and ER-overload response (EOR) are functionally active in maintaining cell homeostasis. Recently we prepared Chinese hamster ovary (CHO) cells expressing mutant antithrombin (AT)(C95R) under control of the Tet-On system and showed that AT(C95R) accumulated in Russell bodies (RB), large distinctive structures derived from the ER. To characterize whether ER stress takes place in CHO cells, we examined characteristic UPR and EOR in ER stress responses. We found that the induction of ER chaperones such as Grp97, Grp78 and protein disulfide isomerase (PDI) was limited to a maximum of approximately two-fold. The processing of X-box-binding protein-1 (XBP1) mRNA and the phosphorylation of eukaryotic translation initiation factor 2α (eIF2α) subunit were not induced. Furthermore, the activation of nuclear factor-kappa B (NF-κB) was not observed. In contrast, CHO cells displayed UPR and EOR when the cells were treated with thapsigargin and tumor necrosis factor (TNF)-α, respectively. In addition, a portion of the mutant AT(C95R) was degraded through proteasomes and autophagy. CHO cells do respond to ER stress but the folding state of mutant AT(C95R) does not appear to activate the ER stress signal pathway.

Optimized polymer enhanced foam flooding for ordinary heavy oil reservoir after cross-linked polymer flooding.

PubMed

Sun, Chen; Hou, Jian; Pan, Guangming; Xia, Zhizeng

2016-01-01

A successful cross-linked polymer flooding has been implemented in JD reservoir, an ordinary heavy oil reservoir with high permeability zones. For all that, there are still significant volumes of continuous oil remaining in place, which can not be easily extracted due to stronger vertical heterogeneity. Considering selective plugging feature, polymer enhanced foam (PEF) flooding was taken as following EOR technology for JD reservoir. For low cost and rich source, natural gas was used as foaming gas in our work. In the former work, the surfactant systems CEA/FSA1 was recommended as foam agent for natural gas foam flooding after series of compatibility studies. Foam performance evaluation experiments showed that foaming volume reached 110 mL, half-life time reached 40 min, and dimensionless filter coefficient reached 1.180 when CEA/FSA1 reacted with oil produced by JD reservoir. To compare the recovery efficiency by different EOR technologies, series of oil displacement experiments were carried out in a parallel core system which contained cores with relatively high and low permeability. EOR technologies concerned in our work include further cross-linked polymer (C-P) flooding, surfactant-polymer (S-P) flooding, and PEF flooding. Results showed that PEF flooding had the highest enhanced oil recovery of 19.2 % original oil in place (OOIP), followed by S-P flooding (9.6 % OOIP) and C-P flooding (6.1 % OOIP). Also, produced liquid percentage results indicated PEF flooding can efficiently promote the oil recovery in the lower permeability core by modifying the injection profile.

Enhanced sampling simulation analysis of the structure of lignin in the THF–water miscibility gap

DOE PAGES

Smith, Micholas Dean; Petridis, Loukas; Cheng, Xiaolin; ...

2016-01-26

Using temperature replica-exchange molecular dynamics, we characterize a globule-to-coil transition for a softwood-like lignin biopolymer in a tetrahydrofuran (THF)-water cosolvent system at temperatures at which the cosolvent undergoes a de-mixing transition. The lignin is found to be in a coil state, similar to that in the high-temperature miscible region. Analysis of the transition kinetics indicates that THF acts in a surfactant-like fashion. In conclusion, the present study thus suggests that THF-water based pretreatments may efficiently remove lignin from biomass even at relatively low (non-water boiling) temperatures.

Synthesis and phase behavior of end-functionalized associating polymers

NASA Astrophysics Data System (ADS)

Wrue, Michelle H.

We have explored polymer blend phase behavior in the presence of multiple hydrogen bonding end-groups. This work details the synthesis of functionalized polymers and their subsequent use in miscibility studies. The synthesis of end-functionalized hydrogen bonding polymers and the investigation of their physical properties and miscibility is presented. Mono-functional and telechelic ureidopyrimidinone (UPy) functionalized polymers were prepared by two main routes: post-polymerization functionalization (of commercially available or synthesized polymers); and polymerization of monomers using a functionalized initiator. UPy-functionalized polymers were prepared with a variety of polymer backbones including poly(ethylene oxide)s; poly(butadiene)s, poly(dimethyl siloxanxe)s; poly(styrene)s and poly(methyl methacrylate)s. The most successful route to polymers with UPy end-groups was atom transfer radical polymerization (ATRP) using a UPy-functionalized initiator, followed by atom transfer radical coupling (ATRC). The incorporation of ureidopyrimidinone end-groups was shown to affect the physical properties of the polymer backbone. Parent polymers that were liquids became viscous liquids or waxy solids upon UPy-functionalization of chain end. UPy-functionalization of a hydroxyl-terminated polybutadiene (HO-PB-OH) resulted in a waxy solid while the HO-PB-OH precursor was a viscous liquid. The thermal properties of functionalized polymers also differed from those of the unfunctionalized parent polymers. Hot-stage optical microscopy revealed that UPy-functionalized PEO displayed a depressed melting point relative to the analogous unfunctionalized precursor. Differential scanning calorimetry was also used to investigate the synthesized UPy-polymers. UPy-functionalized polystyrenes and poly(methyl methacrylate)s showed an increased T g compared to the equivalent homopolymer standards. This increased Tg was determined to be dependent upon the fraction of UPy groups present and chemical cleavage of the end-groups resulted in Tgs near those observed for polymer standards of comparable molecular weight. Aggregation of UPy end-groups in solution was observed using gel permeation chromatography. Aggregation was only observed for telechelic samples of low molecular weight, indicating that the aggregation of end-groups is dependent upon the concentration of the end-groups. The effect of UPy end-groups on blend miscibility was studied in solution using laser light scattering and in the melt state was using laser light scattering, optical microscopy and differential scanning calorimetry. The incorporation of associating groups onto one end of either blend component decreases miscibility relative to unfunctionalized parent blends. Lower miscibility was also observed for blends in which both components were mono-functionalized with associating end-groups. The largest decrease in miscibility was observed for blends containing telechelic UPy-functionalized polymers, which were immiscible across the entire composition range.

Stomach Cancer Following Hodgkin Lymphoma, Testicular Cancer and Cervical Cancer: A Pooled Analysis of Three International Studies with a Focus on Radiation Effects.

PubMed

Gilbert, Ethel S; Curtis, Rochelle E; Hauptmann, Michael; Kleinerman, Ruth A; Lynch, Charles F; Stovall, Marilyn; Smith, Susan A; Weathers, Rita; Andersson, Michael; Dores, Graça M; Fraumeni, Joseph F; Fossa, Sophie D; Hall, Per; Hodgson, David C; Holowaty, Eric J; Joensuu, Heikki; Johannesen, Tom B; Langmark, Froydis; Kaijser, Magnus; Pukkala, Eero; Rajaraman, Preetha; Storm, Hans H; Vaalavirta, Leila; van den Belt-Dusebout, Alexandra W; Aleman, Berthe M; Travis, Lois B; Morton, Lindsay M; van Leeuwen, Flora E

2017-02-01

To further understand the risk of stomach cancer after fractionated high-dose radiotherapy, we pooled individual-level data from three recent stomach cancer case-control studies. These studies were nested in cohorts of five-year survivors of first primary Hodgkin lymphoma (HL), testicular cancer (TC) or cervical cancer (CX) from seven countries. Detailed data were abstracted from patient records and radiation doses were reconstructed to the site of the stomach cancer for cases and to the corresponding sites for matched controls. Among 327 cases and 678 controls, mean doses to the stomach were 15.3 Gy, 24.7 Gy and 1.9 Gy, respectively, for Hodgkin lymphoma, testicular cancer and cervical cancer survivors, with an overall mean dose of 10.3 Gy. Risk increased with increasing radiation dose to the stomach cancer site (P < 0.001) with no evidence of nonlinearity or of a downturn at the highest doses (≥35 Gy). The pooled excess odds ratio per Gy (EOR/Gy) was 0.091 [95% confidence interval (CI): 0.036-0.20] with estimates of 0.049 (95% CI: 0.007-0.16) for Hodgkin lymphoma, 0.27 (95% CI: 0.054-1.44) for testicular cancer and 0.096 (95% CI: -0.002-0.39) for cervical cancer (P homogeneity = 0.25). The EOR/Gy increased with time since exposure (P trend = 0.004), with an EOR/Gy of 0.38 (95% CI: 0.12-1.04) for stomach cancer occurring ≥20 years postirradiation corresponding to odds ratios of 4.8 and 10.5 at radiation doses to the stomach of 10 and 25 Gy, respectively. Of 111 stomach cancers occurring ≥20 years after radiotherapy, 63.8 (57%) could be attributed to radiotherapy. Our findings differ from those based on Japanese atomic-bomb survivors, where the overall EOR/Gy was higher and where there was no evidence of an increase with time since exposure. By pooling data from three studies, we demonstrated a clear increase in stomach cancer risk over a wide range of doses from fractionated radiotherapy with the highest risks occurring many years after exposure. These findings highlight the need to directly evaluate the health effects of high-dose fractionated radiotherapy rather than relying on the data of persons exposed at low and moderate acute doses.

Do End-of-Rotation and End-of-Shift Assessments Inform Clinical Competency Committees’ (CCC) Decisions?

PubMed Central

Regan, Linda; Cope, Leslie; Omron, Rodney; Bright, Leah; Bayram, Jamil D.

2018-01-01

Introduction Clinical Competency Committees (CCC) require reliable, objective data to inform decisions regarding assignment of milestone proficiency levels, which must be reported to the Accreditation Council for Graduate Medical Education. After the development of two new assessment methods, the end-of-shift (EOS) assessment and the end-of-rotation (EOR) assessment, we sought to evaluate their performance. We report data on the concordance between these assessments, as well as how each informs the final proficiency level determined in biannual CCC meetings. We hypothesized that there would be a high concordance level between the two assessment methods, including concordance of both the EOS and EOR with the final proficiency level designation by the CCC. Methods The residency program is an urban academic four-year emergency medicine residency with 48 residents. After their shifts in the emergency department (ED), residents handed out EOS assessment forms asking about individual milestones from 15 subcompetencies to supervising physicians, as well as triggered electronic EOR-doctor (EORd) assessments to supervising doctors and EOR-nurse (EORn) to nurses they had worked with after each two-week ED block. EORd assessments contained the full proficiency level scale from 16 subcompetencies, while EORn assessments contained four subcompetencies. Data reports were generated after each six-month assessment period and data was aggregated. We calculated Spearman’s rank order correlations for correlations between assessment types and between assessments and final CCC proficiency levels. Results Over 24 months, 5,234 assessments were completed. The strongest correlations with CCC proficiency levels were the EORd for the immediate six-month assessment period prior (rs 0.71–0.84), and the CCC proficiency levels from the previous six-months (rs 0.83–0.92). EOS assessments had weaker correlations (rs 0.49 to 0.62), as did EORn (rs 0.4 to 0.73). Conclusion End-of-rotation assessments completed by supervising doctors are most highly correlated with final CCC proficiency level designations, while end-of-shift assessments and end-of-rotation assessments by nurses did not correlate strongly with final CCC proficiency levels, both with overestimation of levels noted. Every level of proficiency the CCC assigned appears to be highly correlated with the designated level in the immediate six-month period, perhaps implying CCC members are biased by previous level assignments. PMID:29383066

Do End-of-Rotation and End-of-Shift Assessments Inform Clinical Competency Committees' (CCC) Decisions?

PubMed

Regan, Linda; Cope, Leslie; Omron, Rodney; Bright, Leah; Bayram, Jamil D

2018-01-01

Clinical Competency Committees (CCC) require reliable, objective data to inform decisions regarding assignment of milestone proficiency levels, which must be reported to the Accreditation Council for Graduate Medical Education. After the development of two new assessment methods, the end-of-shift (EOS) assessment and the end-of-rotation (EOR) assessment, we sought to evaluate their performance. We report data on the concordance between these assessments, as well as how each informs the final proficiency level determined in biannual CCC meetings. We hypothesized that there would be a high concordance level between the two assessment methods, including concordance of both the EOS and EOR with the final proficiency level designation by the CCC. The residency program is an urban academic four-year emergency medicine residency with 48 residents. After their shifts in the emergency department (ED), residents handed out EOS assessment forms asking about individual milestones from 15 subcompetencies to supervising physicians, as well as triggered electronic EOR-doctor (EORd) assessments to supervising doctors and EOR-nurse (EORn) to nurses they had worked with after each two-week ED block. EORd assessments contained the full proficiency level scale from 16 subcompetencies, while EORn assessments contained four subcompetencies. Data reports were generated after each six-month assessment period and data was aggregated. We calculated Spearman's rank order correlations for correlations between assessment types and between assessments and final CCC proficiency levels. Over 24 months, 5,234 assessments were completed. The strongest correlations with CCC proficiency levels were the EORd for the immediate six-month assessment period prior (r s 0.71-0.84), and the CCC proficiency levels from the previous six-months (r s 0.83-0.92). EOS assessments had weaker correlations (r s 0.49 to 0.62), as did EORn (r s 0.4 to 0.73). End-of-rotation assessments completed by supervising doctors are most highly correlated with final CCC proficiency level designations, while end-of-shift assessments and end-of-rotation assessments by nurses did not correlate strongly with final CCC proficiency levels, both with overestimation of levels noted. Every level of proficiency the CCC assigned appears to be highly correlated with the designated level in the immediate six-month period, perhaps implying CCC members are biased by previous level assignments.

The Cu-Li-Sn Phase Diagram: Isopleths, Liquidus Projection and Reaction Scheme

PubMed Central

Flandorfer, Hans

2016-01-01

The Cu-Li-Sn phase diagram was constructed based on XRD and DTA data of 60 different alloy compositions. Eight ternary phases and 14 binary solid phases form 44 invariant ternary reactions, which are illustrated by a Scheil-Schulz reaction scheme and a liquidus projection. Phase equilibria as a function of concentration and temperature are shown along nine isopleths. This report together with an earlier publication of our group provides for the first time comprehensive investigations of phase equilibria and respective phase diagrams. Most of the phase equilibria could be established based on our experimental results. Only in the Li-rich part where many binary and ternary compounds are present estimations had to be done which are all indicated by dashed lines. A stable ternary miscibility gap could be found which was predicted by modelling the liquid ternary phase in a recent work. The phase diagrams are a crucial input for material databases and thermodynamic optimizations regarding new anode materials for high-power Li-ion batteries. PMID:27788175

Miscibility and interactions of animal and plant sterols with choline plasmalogen in binary and multicomponent model systems.

PubMed

Hąc-Wydro, Katarzyna; Luty, Katarzyna

2014-04-01

In this work miscibility and interactions of sterols with choline plasmalogen (PC-plasm) in Langmuir monolayers were studied. Moreover, the properties of cholesterol/phosphatidylcholine/plasmalogen mixtures of different PC-plasm concentration were investigated. The foregoing systems were treated as a model of cancer cell membranes, which are of higher plasmalogen level than normal cells. Finally, the influence of β-sitosterol and stigmasterol (phytosterols differing in anticancer potency) on these mixtures was verified. The properties of monolayers were analyzed based on the parameters derived from the surface pressure-area isotherms and images taken with Brewster Angle Microscope. It was found that at 30% of sterol in sterol/plasmalogen monolayer the lipids are immiscible and 3D crystallites are formed within the film. Cholesterol molecules mix favorably with PC-plasm at Xchol ≥ 0.5, while the investigated phytosterols only at their prevailing proportion in binary system. The increase of choline plasmalogen in cholesterol/phosphatidylcholine monolayer causes destabilization of the system. Moreover, the incorporation of phytosterols into cholesterol/phosphatidylcholine+PC-plasm mixtures disturbed membrane morphology and this effect was stronger for β-sitosterol as compared to stigmasterol. It was concluded that the presence of vinyl ether bond at sn-1 position in PC-plasm molecule strongly affects miscibility of choline plasmalogen with sterols. The comparison of the collected data with those reported in literature allowed one to conclude that miscibility and interactions of sterols with PC-plasm are less favorable than those with phosphatidylcholine. It was also suggested that overexpression of plasmalogens in cancer cell membranes may be a factor differentiating sensitivity of cells to anticancer effect of phytosterols. Copyright © 2014 Elsevier B.V. All rights reserved.

Multiscale structure, interfacial cohesion, adsorbed layers, miscibility and properties in dense polymer-particle mixtures

NASA Astrophysics Data System (ADS)

Schweizer, Ken

2012-02-01

A major goal in polymer nanocomposite research is to understand and predict how the chemical and physical nature of individual polymers and nanoparticles, and thermodynamic state (temperature, composition, solvent dilution, filler loading), determine bulk assembly, miscibility and properties. Microscopic PRISM theory provides a route to this goal for equilibrium disordered mixtures. A major prediction is that by manipulating the net polymer-particle interfacial attraction, miscibility is realizable via the formation of thin thermodynamically stable adsorbed layers, which, however, are destroyed by entropic depletion and bridging attraction effects if interface cohesion is too weak or strong, respectively. This and related issues are quantitatively explored for miscible mixtures of hydrocarbon polymers, silica nanospheres, and solvent using x-ray scattering, neutron scattering and rheology. Under melt conditions, quantitative agreement between theory and silica scattering experiments is achieved under both steric stabilization and weak depletion conditions. Using contrast matching neutron scattering to characterize the collective structure factors of polymers, particles and their interface, the existence and size of adsorbed polymer layers, and their consequences on microstructure, is determined. Failure of the incompressible RPA, accuracy of PRISM theory, the nm thickness of adsorbed layers, and qualitative sensitivity of the bulk modulus to interfacial cohesion and particle size are demonstrated for concentrated PEO-silica-ethanol nanocomposites. Temperature-dependent complexity is discovered when water is the solvent, and nonequilibrium effects emerge for adsorbing entangled polymers that strongly impact structure. By varying polymer chemistry, the effect of polymer-particle attraction on the intrinsic viscosity is explored with striking non-classical effects observed. This work was performed in collaboration with S.Y.Kim, L.M.Hall, C.Zukoski and B.Anderson.

Carbon Dioxide-Water Emulsions for Enhanced Oil Recovery and Permanent Sequestration of Carbon Dioxide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ryan, David; Golomb, Dan; Shi, Guang

2011-09-30

This project involves the use of an innovative new invention Particle Stabilized Emulsions (PSEs) of Carbon Dioxide-in-Water and Water-in-Carbon Dioxide for Enhanced Oil Recovery (EOR) and Permanent Sequestration of Carbon Dioxide. The EOR emulsion would be injected into a semi-depleted oil reservoir such as Dover 33 in Otsego County, Michigan. It is expected that the emulsion would dislocate the stranded heavy crude oil from the rock granule surfaces, reduce its viscosity, and increase its mobility. The advancing emulsion front should provide viscosity control which drives the reduced-viscosity oil toward the production wells. The make-up of the emulsion would be subsequentlymore » changed so it interacts with the surrounding rock minerals in order to enhance mineralization, thereby providing permanent sequestration of the injected CO{sub 2}. In Phase 1 of the project, the following tasks were accomplished: 1. Perform laboratory scale (mL/min) refinements on existing procedures for producing liquid carbon dioxide-in-water (C/W) and water-in-liquid carbon dioxide (W/C) emulsion stabilized by hydrophilic and hydrophobic fine particles, respectively, using a Kenics-type static mixer. 2. Design and cost evaluate scaled up (gal/min) C/W and W/C emulsification systems to be deployed in Phase 2 at the Otsego County semi-depleted oil field. 3. Design the modifications necessary to the present CO{sub 2} flooding system at Otsego County for emulsion injection. 4. Design monitoring and verification systems to be deployed in Phase 2 for measuring potential leakage of CO{sub 2} after emulsion injection. 5. Design production protocol to assess enhanced oil recovery with emulsion injection compared to present recovery with neat CO{sub 2} flooding. 6. Obtain Federal and State permits for emulsion injection. Initial research focused on creating particle stabilized emulsions with the smallest possible globule size so that the emulsion can penetrate even low-permeability crude oilcontaining formations or saline aquifers. The term globule refers to the water or liquid carbon dioxide droplets sheathed with ultrafine particles dispersed in the continuous external medium, liquid CO{sub 2} or H{sub 2}O, respectively. The key to obtaining very small globules is the shear force acting on the two intermixing fluids, and the use of ultrafine stabilizing particles or nanoparticles. We found that using Kenics-type static mixers with a shear rate in the range of 2700 to 9800 s{sup -1} and nanoparticles between 100-300 nm produced globule sizes in the 10 to 20 μm range. Particle stabilized emulsions with that kind of globule size should easily penetrate oil-bearing formations or saline aquifers where the pore and throat size can be on the order of 50 μm or larger. Subsequent research focused on creating particle stabilized emulsions that are deemed particularly suitable for Permanent Sequestration of Carbon Dioxide. Based on a survey of the literature an emulsion consisting of 70% by volume of water, 30% by volume of liquid or supercritical carbon dioxide, and 2% by weight of finely pulverized limestone (CaCO{sub 3}) was selected as the most promising agent for permanent sequestration of CO{sub 2}. In order to assure penetration of the emulsion into tight formations of sandstone or other silicate rocks and carbonate or dolomite rock, it is necessary to use an emulsion consisting of the smallest possible globule size. In previous reports we described a high shear static mixer that can create such small globules. In addition to the high shear mixer, it is also necessary that the emulsion stabilizing particles be in the submicron size, preferably in the range of 0.1 to 0.2 μm (100 to 200 nm) size. We found a commercial source of such pulverized limestone particles, in addition we purchased under this DOE Project a particle grinding apparatus that can provide particles in the desired size range. Additional work focused on attempts to generate particle stabilized emulsions with a flow through, static mixer based apparatus under a variety of conditions that are suitable for permanent sequestration of carbon dioxide. A variety of mixtures of water, CO{sub 2} and particles may also provide suitable emulsions capable of PS. In addition, it is necessary to test the robustness of PSE formation as composition changes to be certain that emulsions of appropriate size and stability form under conditions that might vary during actual large scale EOR and sequestration operations. The goal was to lay the groundwork for an apparatus and formulation that would produce homogenous microemulsions of CO{sub 2}-in-water capable of readily mixing with the waters of deep saline aquifers and allow a safer and more permanent sequestration of carbon dioxide. In addition, as a beneficial use, we hoped to produce homogenous microemulsions of water-in-CO{sub 2} capable of readily mixing with pure liquid or supercritical CO{sub 2} for use in Enhanced Oil Recovery (EOR). However, true homogeneous microemulsions have proven very difficult to produce and efforts have not yielded either a formulation or a mixing strategy that gives emulsions that do not settle out or that can be diluted with the continuous phase in varying proportions. Other mixtures of water, CO{sub 2} and particles, that are not technically homogeneous microemulsions, may also provide suitable emulsions capable of PS and EOR. For example, a homogeneous emulsion that is not a microemulsion might also provide all of the necessary characteristics desired. These characteristics would include easy formation, stability over time, appropriate size and the potential for mineralization under conditions that would be encountered under actual large scale sequestration operations. This report also describes work with surrogate systems in order to test conditions.« less

Control of surface adatom kinetics for the growth of high-indium content InGaN throughout the miscibility gap

NASA Astrophysics Data System (ADS)

Moseley, Michael; Lowder, Jonathan; Billingsley, Daniel; Doolittle, W. Alan

2010-11-01

The surface kinetics of InGaN alloys grown via metal-modulated epitaxy (MME) are explored in combination with transient reflection high-energy electron diffraction intensities. A method for monitoring and controlling indium segregation in situ is demonstrated. It is found that indium segregation is more accurately associated with the quantity of excess adsorbed metal, rather than the metal-rich growth regime in general. A modified form of MME is developed in which the excess metal dose is managed via shuttered growth, and high-quality InGaN films throughout the miscibility gap are grown.

A study examining the effects of water-miscible cutting fluids for end milling process of carbon fiber reinforced plastic

NASA Astrophysics Data System (ADS)

Anan, Ruito; Matsuoka, Hironori; Ono, Hajime; Ryu, Takahiro; Nakae, Takashi; Shuto, Schuichi; Watanabe, Suguru; Sato, Yuta

2017-04-01

This study examined the improvements to the tool life and finished surface roughness by using water-miscible cutting fluids in carbon fiber reinforced plastics end milling. In cutting tests, it was found that the use of emulsion type, soluble type, and solution type cutting fluids improved tool life compared with the case of dry cutting. Specifically, significant differences in tool life were observed at a high cutting speed of 171 m/min. In addition, the finished surface exhibited a low level of roughness when the solution type cutting fluid was used, regardless of the cutting speed.

Gradient and size effects on spinodal and miscibility gaps

NASA Astrophysics Data System (ADS)

Tsagrakis, Ioannis; Aifantis, Elias C.

2018-05-01

A thermodynamically consistent model of strain gradient elastodiffusion is developed. Its formulation is based on the enhancement of a robust theory of gradient elasticity, known as GRADELA, to account for a Cahn-Hilliard type of diffusion. Linear stability analysis is employed to determine the influence of concentration and strain gradients on the spinodal decomposition. For finite domains, spherically symmetric conditions are considered, and size effects on spinodal and miscibility gaps are discussed. The theoretical predictions are in agreement with the experimental trends, i.e., both gaps shrink as the grain diameter decreases and they are completely eliminated for crystals smaller than a critical size.

Instability patterns in a miscible core annular flow

NASA Astrophysics Data System (ADS)

D'Olce, Marguerite; Martin, Jerome; Rakotomalala, Nicole; Salin, Dominique; Talon, Laurent

2006-11-01

Laboratoire FAST, batiment 502, campus universitaire, 91405 Orsay Cedex (France). Experiments are performed with two miscible fluids of equal density but different viscosities. The fluids are injected co-currently and concentrically into a cylindrical pipe. The so-obtained base state is an axisymmetric parallel flow, for which the ratio of the flow rates of the two fluids monitors the relative amount (and so the radius) of the fluids. Depending on this relative amount and on the total flow rate of the fluids, unstable axisymmetric patterns such as mushrooms and pearls are observed. We delineate the diagram of occurrence of the two patterns and characterize the instabilities.

Buoyancy driven mixing of miscible fluids by volumetric energy deposition of microwaves.

PubMed

Wachtor, Adam J; Mocko, Veronika; Williams, Darrick J; Goertz, Matthew P; Jebrail, Farzaneh F

2013-01-01

An experiment that seeks to investigate buoyancy driven mixing of miscible fluids by microwave volumetric energy deposition is presented. The experiment involves the use of a light, non-polar fluid that initially rests on top of a heavier fluid which is more polar. Microwaves preferentially heat the polar fluid, and its density decreases due to thermal expansion. As the microwave heating continues, the density of the lower fluid eventually becomes less than that of the upper, and buoyancy driven Rayleigh-Taylor mixing ensues. The choice of fluids is crucial to the success of the experiment, and a description is given of numerous fluid combinations considered and characterized. After careful consideration, the miscible pair of toluene/tetrahydrofuran (THF) was determined as having the best potential for successful volumetric energy deposition buoyancy driven mixing. Various single fluid calibration experiments were performed to facilitate the development of a heating theory. Thereafter, results from two-fluid mixing experiments are presented that demonstrate the capability of this novel Rayleigh-Taylor driven experiment. Particular interest is paid to the onset of buoyancy driven mixing and unusual aspects of the experiment in the context of typical Rayleigh-Taylor driven mixing.

Lifecycle of miscible viscous fingering: onset to shutdown

NASA Astrophysics Data System (ADS)

Nijjer, Japinder S.; Hewitt, Duncan R.; Neufeld, Jerome A.

2017-11-01

When a viscous fluid is injected into a porous medium or Hele-Shaw cell that is initially saturated with a more viscous fluid, the flow can be unstable to viscous fingering. We investigate the long-time dynamics of miscible viscous fingering in a homogeneous, planar, two-dimensional porous medium using high-resolution numerical simulations. At late times, we identify a new flow regime which consists of a pair of counter-propagating fingers that diffuse and slow, leaving a linearly well-mixed interior. We derive an analytic solution for this regime, and show that, in contrast to previous suggestions, the flow always evolves to this regime irrespective of the viscosity ratio and Peclet number. As a consequence, we find the instability can only ever generate a finite amount of advective mixing. We also describe the full life-cycle of miscible viscous fingering, which can be partitioned into three regimes: an early-time linearly unstable regime, an intermediate-time non-linear regime, and a late-time exchange-flow regime. We identify, using linear stability theory, a critical Peclet number below which the flow is always stable, and derive a model for the evolution of the transversely averaged concentration in the intermediate-time regime, which extends previous empirical models.

Competing Stereocomplexation and Homocrystallization of Poly(l-lactic acid)/Poly(d-lactic acid) Racemic Mixture: Effects of Miscible Blending with Other Polymers.

PubMed

Bao, Jianna; Xue, Xiaojia; Li, Kai; Chang, Xiaohua; Xie, Qing; Yu, Chengtao; Pan, Pengju

2017-07-20

Promoting the stereocomplexation ability of high-molecular-weight poly(l-lactic acid) (PLLA) and poly(d-lactic acid) (PDLA) is an efficient way to improve the thermal resistance of the resulting materials. Herein, we studied the competing crystallization kinetics, polymorphic crystalline structure, and lamellae structure of the PLLA/PDLA component in its miscible blends with poly(vinyl acetate) (PVAc) and proposed a method to improve the stereocomplexation ability of PLLA and PDLA through miscible blending with the other polymer. Crystallization of the PLLA/PDLA component is suppressed after the addition of PVAc, due to the dilution effect. The stereocomplexation ability of PLLA and PDLA is enhanced by blending with PVAc; this becomes more obvious at a high PVAc content (≥50 wt %) but less significant with the further increase of PLLA, PDLA molecular weights. Almost exclusive formation of SCs is achieved for PLLA and PDLA after blending with a large proportion of PVAc (e.g., 75 wt %). Incorporation of PVAc also facilitates the HC-to-SC structural reorganization upon heating. The increased chain mobility, decreased equilibrium melting point, and enhanced intermolecular interactions may account for the preferential stereocomplexation in PLLA/PDLA/PVAc blends.

Permanganate gel (PG) for groundwater remediation: compatibility, gelation, and release characteristics.

PubMed

Lee, Eung Seok; Olson, Pamela R; Gupta, Neha; Solpuker, Utku; Schwartz, Franklin W; Kim, Yongje

2014-02-01

Permanganate (MnO4(-)) is a strong oxidant that is widely used for treating chlorinated ethylenes in groundwater. This study aims to develop hyper-saline MnO4(-) solution (MnO4(-) gel; PG) that can be injected into aquifers via wells, slowly gelates over time, and slowly release MnO4(-) to flowing water. In this study, compatibility and miscibility of gels, such as chitosan, aluminosilicate, silicate, and colloidal silica gels, with MnO4(-) were tested. Of these gels, chitosan was reactive with MnO4(-). Aluminosilicates were compatible but not readily miscible with MnO4(-). Silicates and colloidal silica were both compatible and miscible with MnO4(-), and gelated with addition of KMnO4 granules. Colloidal silica has low initial viscosity (<15cP), exhibited delayed gelation characteristics with the lag times ranging from 0 to 200min. Release of MnO4(-) from the colloidal silica-based PG gel occurred in a delayed fashion, with maximum duration of 24h. These results suggested that colloidal silica can be used to create PG or delayed-gelling forms containing other oxidants which can be used for groundwater remediation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Early opportunities of CO₂ geological storage deployment in coal chemical industry in China

DOE PAGES

Wei, Ning; Li, Xiaochun; Liu, Shengnan; ...

2014-12-31

Carbon dioxide capture and geological storage (CCS) is regarded as a promising option for climate change mitigation; however, the high capture cost is the major barrier to large-scale deployment of CCS technologies. High-purity CO₂ emission sources can reduce or even avoid the capture requirements and costs. Among these high-purity CO₂ sources, certain coal chemical industry processes are very important, especially in China. In this paper, the basic characteristics of coal chemical industries in China is investigated and analyzed. As of 2013 there were more than 100 coal chemical plants in operation. These emission sources together emit 430 million tons CO₂more » per year, of which about 30% are emit high-purity and pure CO₂ (CO₂ concentration >80% and >98.5% respectively). Four typical source-sink pairs are chosen for techno-economic evaluation, including site screening and selection, source-sink matching, concept design, and economic evaluation. The technical-economic evaluation shows that the levelized cost of a CO₂ capture and aquifer storage project in the coal chemistry industry ranges from 14 USD/t to 17 USD/t CO₂. When a 15USD/t CO₂ tax and 20USD/t for CO₂ sold to EOR are considered, the levelized cost of CCS project are negative, which suggests a benefit from some of these CCS projects. This might provide China early opportunities to deploy and scale-up CCS projects in the near future.« less

Defining Glioblastoma Resectability Through the Wisdom of the Crowd: A Proof-of-Principle Study.

PubMed

Sonabend, Adam M; Zacharia, Brad E; Cloney, Michael B; Sonabend, Aarón; Showers, Christopher; Ebiana, Victoria; Nazarian, Matthew; Swanson, Kristin R; Baldock, Anne; Brem, Henry; Bruce, Jeffrey N; Butler, William; Cahill, Daniel P; Carter, Bob; Orringer, Daniel A; Roberts, David W; Sagher, Oren; Sanai, Nader; Schwartz, Theodore H; Silbergeld, Daniel L; Sisti, Michael B; Thompson, Reid C; Waziri, Allen E; McKhann, Guy

2017-04-01

Extent of resection (EOR) correlates with glioblastoma outcomes. Resectability and EOR depend on anatomical, clinical, and surgeon factors. Resectability likely influences outcome in and of itself, but an accurate measurement of resectability remains elusive. An understanding of resectability and the factors that influence it may provide a means to control a confounder in clinical trials and provide reference for decision making. To provide proof of concept of the use of the collective wisdom of experienced brain tumor surgeons in assessing glioblastoma resectability. We surveyed 13 academic tumor neurosurgeons nationwide to assess the resectability of newly diagnosed glioblastoma. Participants reviewed 20 cases, including digital imaging and communications in medicine-formatted pre- and postoperative magnetic resonance images and clinical vignettes. The selected cases involved a variety of anatomical locations and a range of EOR. Participants were asked about surgical goal, eg, gross total resection, subtotal resection (STR), or biopsy, and rationale for their decision. We calculated a "resectability index" for each lesion by pooling responses from all 13 surgeons. Neurosurgeons' individual surgical goals varied significantly ( P = .015), but the resectability index calculated from the surgeons' pooled responses was strongly correlated with the percentage of contrast-enhancing residual tumor ( R = 0.817, P < .001). The collective STR goal predicted intraoperative decision of intentional STR documented on operative notes ( P < .01) and nonresectable residual ( P < .01), but not resectable residual. In this pilot study, we demonstrate the feasibility of measuring the resectability of glioblastoma through crowdsourcing. This tool could be used to quantify resectability, a potential confounder in neuro-oncology clinical trials. Copyright © 2016 by the Congress of Neurological Surgeons

Spectral performance of Square Kilometre Array Antennas - II. Calibration performance

NASA Astrophysics Data System (ADS)

Trott, Cathryn M.; de Lera Acedo, Eloy; Wayth, Randall B.; Fagnoni, Nicolas; Sutinjo, Adrian T.; Wakley, Brett; Punzalan, Chris Ivan B.

2017-09-01

We test the bandpass smoothness performance of two prototype Square Kilometre Array (SKA) SKA1-Low log-periodic dipole antennas, SKALA2 and SKALA3 ('SKA Log-periodic Antenna'), and the current dipole from the Murchison Widefield Array (MWA) precursor telescope. Throughout this paper, we refer to the output complex-valued voltage response of an antenna when connected to a low-noise amplifier, as the dipole bandpass. In Paper I, the bandpass spectral response of the log-periodic antenna being developed for the SKA1-Low was estimated using numerical electromagnetic simulations and analysed using low-order polynomial fittings, and it was compared with the HERA antenna against the delay spectrum metric. In this work, realistic simulations of the SKA1-Low instrument, including frequency-dependent primary beam shapes and array configuration, are used with a weighted least-squares polynomial estimator to assess the ability of a given prototype antenna to perform the SKA Epoch of Reionisation (EoR) statistical experiments. This work complements the ideal estimator tolerances computed for the proposed EoR science experiments in Trott & Wayth, with the realized performance of an optimal and standard estimation (calibration) procedure. With a sufficient sky calibration model at higher frequencies, all antennas have bandpasses that are sufficiently smooth to meet the tolerances described in Trott & Wayth to perform the EoR statistical experiments, and these are primarily limited by an adequate sky calibration model and the thermal noise level in the calibration data. At frequencies of the Cosmic Dawn, which is of principal interest to SKA as one of the first next-generation telescopes capable of accessing higher redshifts, the MWA dipole and SKALA3 antenna have adequate performance, while the SKALA2 design will impede the ability to explore this era.

Designing Successful Next-Generation Instruments to Detect the Epoch of Reionization

NASA Astrophysics Data System (ADS)

Thyagarajan, Nithyanandan; Hydrogen Epoch of Reionization Array (HERA) team, Murchison Widefield Array (MWA) team

2018-01-01

The Epoch of Reionization (EoR) signifies a period of intense evolution of the Inter-Galactic Medium (IGM) in the early Universe caused by the first generations of stars and galaxies, wherein they turned the neutral IGM to be completely ionized by redshift ≥ 6. This important epoch is poorly explored to date. Measurement of redshifted 21 cm line from neutral Hydrogen during the EoR is promising to provide the most direct constraints of this epoch. Ongoing experiments to detect redshifted 21 cm power spectrum during reionization, including the Murchison Widefield Array (MWA), Precision Array for Probing the Epoch of Reionization (PAPER), and the Low Frequency Array (LOFAR), appear to be severely affected by bright foregrounds and unaccounted instrumental systematics. For example, the spectral structure introduced by wide-field effects, aperture shapes and angular power patterns of the antennas, electrical and geometrical reflections in the antennas and electrical paths, and antenna position errors can be major limiting factors. These mimic the 21 cm signal and severely degrade the instrument performance. It is imperative for the next-generation of experiments to eliminate these systematics at their source via robust instrument design. I will discuss a generic framework to set cosmologically motivated antenna performance specifications and design strategies using the Precision Radio Interferometry Simulator (PRISim) -- a high-precision tool that I have developed for simulations of foregrounds and the instrument transfer function intended primarily for 21 cm EoR studies, but also broadly applicable to interferometer-based intensity mapping experiments. The Hydrogen Epoch of Reionization Array (HERA), designed in-part based on this framework, is expected to detect the 21 cm signal with high significance. I will present this framework and the simulations, and their potential for designing upcoming radio instruments such as HERA and the Square Kilometre Array (SKA).

Comparison of endoscope- versus microscope-assisted resection of deep-seated intracranial lesions using a minimally invasive port retractor system.

PubMed

Hong, Christopher S; Prevedello, Daniel M; Elder, J Bradley

2016-03-01

Tubular brain retractors may improve access to deep-seated brain lesions while potentially reducing the risks of collateral neurological injury associated with standard microsurgical approaches. Here, microscope-assisted resection of lesions using tubular retractors is assessed to determine if it is superior to endoscope-assisted surgery due to the technological advancements associated with modern tubular ports and surgical microscopes. Following institutional approval of the tubular port, data obtained from the initial 20 patients to undergo transportal resection of deep-seated brain lesions were analyzed in this study. The pathological entities of the resected tissues included metastatic tumors (8 patients), glioma (7), meningioma (1), neurocytoma (1), radiation necrosis (1), primitive neuroectodermal tumor (1), and hemangioblastoma (1). Surgery incorporated endoscopic (5 patients) or microscopic (15) assistance. The locations included the basal ganglia (11 patients), cerebellum (4), frontal lobe (2), temporal lobe (2), and parietal lobe (1). Cases were reviewed for neurological outcomes, extent of resection (EOR), and complications. Technical data for the port, surgical microscope, and endoscope were analyzed. EOR was considered total in 14 (70%), near total (> 95%) in 4 (20%), and subtotal (< 90%) in 2 (10%) of 20 patients. Incomplete resection was associated with the basal ganglia location (p < 0.05) and use of the endoscope (p < 0.002). Four of 5 (80%) endoscope-assisted cases were near-total (2) or subtotal (2) resection. Histopathological diagnosis, presenting neurological symptoms, and demographics were not associated with EOR. Complication rates were low and similar between groups. Initial experience with tubular retractors favors use of the microscope rather than the endoscope due to a wider and 3D field of view. Improved microscope optics and tubular retractor design allows for binocular vision with improved lighting for the resection of deep-seated brain lesions.

Impact of Laterality on Surgical Outcome of Glioblastoma Patients: A Retrospective Single-Center Study.

PubMed

Coluccia, Daniel; Roth, Tabitha; Marbacher, Serge; Fandino, Javier

2018-06-01

Resection of left hemisphere (LH) tumors is often complicated by the risks of causing language dysfunction. Although neurosurgeons' concerns when operating on the presumed dominant hemisphere are well known, literature evaluating laterality as a predictive surgical parameter in glioblastoma (GB) patients is sparse. We evaluated whether tumor laterality correlated with surgical performance, functional outcome, and survival. All patients with GB treated at our institution between 2006 and 2016 were reviewed. Analysis comprised clinical characteristics, extent of resection (EOR), neurologic outcome, and survival in relation to tumor lateralization. Two hundred thirty-five patients were included. Right hemisphere (RH) tumors were larger and more frequently extended into the frontal lobe. Preoperatively, limb paresis was more frequent in RH, whereas language deficits were more frequent in LH tumors (P = 0.0009 and P < 0.0001, respectively). At 6 months after resection, LH patients presented lower Karnofsky Performance Status (KPS) score (P = 0.036). More patients with LH tumors experienced dysphasia (P < 0.0001), and no difference was seen for paresis. Average EOR was comparable, but complete resection was achieved less often in LH tumors (37.7 vs. 64.8%; P = 0.0028). Although overall survival did not differ between groups, progression-free survival was shorter in LH tumors (7.4 vs. 10.1 months; P = 0.0225). Patients with LH tumors had a pronounced KPS score decline and shorter progression-free survival without effects on overall survival. This observation might partially be attributed to a more conservative surgical resection. Further investigation is needed to assess whether systematic use of awake surgery and intraoperative mapping results in increased EOR and improved quality survival of patients with GB. Copyright © 2018 Elsevier Inc. All rights reserved.

Probabilistic cost estimation methods for treatment of water extracted during CO 2 storage and EOR

DOE PAGES

Graham, Enid J. Sullivan; Chu, Shaoping; Pawar, Rajesh J.

2015-08-08

Extraction and treatment of in situ water can minimize risk for large-scale CO 2 injection in saline aquifers during carbon capture, utilization, and storage (CCUS), and for enhanced oil recovery (EOR). Additionally, treatment and reuse of oil and gas produced waters for hydraulic fracturing will conserve scarce fresh-water resources. Each treatment step, including transportation and waste disposal, generates economic and engineering challenges and risks; these steps should be factored into a comprehensive assessment. We expand the water treatment model (WTM) coupled within the sequestration system model CO 2-PENS and use chemistry data from seawater and proposed injection sites in Wyoming,more » to demonstrate the relative importance of different water types on costs, including little-studied effects of organic pretreatment and transportation. We compare the WTM with an engineering water treatment model, utilizing energy costs and transportation costs. Specific energy costs for treatment of Madison Formation brackish and saline base cases and for seawater compared closely between the two models, with moderate differences for scenarios incorporating energy recovery. Transportation costs corresponded for all but low flow scenarios (<5000 m 3/d). Some processes that have high costs (e.g., truck transportation) do not contribute the most variance to overall costs. Other factors, including feed-water temperature and water storage costs, are more significant contributors to variance. These results imply that the WTM can provide good estimates of treatment and related process costs (AACEI equivalent level 5, concept screening, or level 4, study or feasibility), and the complex relationships between processes when extracted waters are evaluated for use during CCUS and EOR site development.« less

Preference of multi-walled carbon nanotube (MWCNT) to single-walled carbon nanotube (SWCNT) and activated carbon for preparing silica nanohybrid pickering emulsion for chemical enhanced oil recovery (C-EOR)

DOE Office of Scientific and Technical Information (OSTI.GOV)

AfzaliTabar, M.; Alaei, M., E-mail: alaiem@ripi.ir; Ranjineh Khojasteh, R.

The aim of this research was to determine the best nano hybrid that can be used as a Pickering emulsion Chemical Enhanced Oil Recovery (C-EOR). Therefore, we have prepared different carbon structures nano hybrids with SiO{sub 2} nano particles with different weight percent using sol-gel method. The as-prepared nano materials were characterized with X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM) and Thermal Gravimetric Analysis (TGA). Pickering emulsions of these nanohybrids were prepared at pH=7 in ambient temperature and with distilled water. Stability of the mentioned Pickering emulsions was controlled for one month. Emulsion phase morphology was investigated usingmore » optical microscopic imaging. Evaluation results demonstrated that the best sample is the 70% MWCNT/SiO{sub 2} nanohybrid. Stability of the selected nanohybrid (70% MWCNT/SiO{sub 2} nanohybrid) was investigated by alteration of salinity, pH and temperature. Results showed that the mentioned Pickering emulsion has very good stability at 0.1%, 1% salinity, moderate and high temperature (25 °C and 90 °C) and neutral and alkaline pH (7, 10) that is suitable for the oil reservoirs conditions. The effect of the related nano fluid on the wettability of carbonate rock was investigated by measuring the contact angle and interfacial tension. Results show that the nanofluid could significantly change the wettability of the carbonate rock from oil wet to water wet and can decrease the interfacial tension. Therefore, the 70% MWCNT/SiO{sub 2} nanohybrid Pickering emulsion can be used for Chemical Enhanced Oil Recovery (C-EOR).« less

Glioma Surgery: Technological Advances to Achieve a Maximal Safe Resection.

PubMed

Altieri, Roberto; Zenga, Francesco; Fontanella, Marco Maria; Cofano, Fabio; Agnoletti, Alessandro; Spena, Giannantonio; Crobeddu, Emanuela; Fornaro, Riccardo; Ducati, Alessandro; Garbossa, Diego

2015-11-01

Glioblastoma multiforme (GBM) is the most frequent primary central nervous system (CNS) tumor. Despite the best treatment and advances in therapy, prognosis remains poor. One of the mainstays of therapy in GBM is surgical excision. Several studies have confirmed that the extent of resection (EOR) positively influences overall survival (OS) in patients with high-grade gliomas (HGGs). A literature search was performed using PubMed to assess the useful neurosurgical tools to achieve the best neurosurgical performance. In order to achieve the major extent of resection, preserving neurological function, many tools are now available, especially neuronavigation, intraoperative fluorescence, intraoperative ultrasound, and neuromonitoring. In addition to the maximal excision of tumor, the neurosurgeon can use photodynamic therapy (PTD) and local drug delivery (LDD) to improve the local control and bridge conventional radio and chemotherapy. EOR improves OS in patients with HGGs. There are technological possibilities for achieving a complete resection preserving neurological function, and it is not acceptable to perform only biopsy of these lesions.

Application of Sodium Ligno Sulphonate as Surfactant in Enhanced Oil Recovery and Its Feasibility Test for TPN 008 Oil

NASA Astrophysics Data System (ADS)

Prakoso, N. I.; Rochmadi; Purwono, S.

2018-04-01

One of enhanced oil recovery (EOR) methods is using surfactants to reduce the interfacial tension between the injected fluid and the oil in old reservoir. The most important principle in enhanced oil recovery process is the dynamic interaction of surfactants with crude oil. Sodium ligno sulphonate (SLS) is a commercial surfactant and already synthesized from palm solid waste by another researcher. This work aimed to apply SLS as a surfactant for EOR especially in TPN 008 oil from Pertamina Indonesia. In its application as an EOR’s surfactant, SLS shall be passed feasibility test like IFT, thermal stability, compatibility, filtration, molecular weight, density, viscosity and pH tests. The feasibility test is very important for a preliminary test prior to another advanced test. The results demonstrated that 1% SLS solution in formation water (TPN 008) had 0.254 mN/M IFT value and was also great in thermal stability, compatibility, filtration, molecular weight, viscosity and pH test.

Modeling and simulation of multiphase multicomponent multiphysics porous media flows in the context of chemical enhanced oil recovery

NASA Astrophysics Data System (ADS)

Dutta, Sourav; Daripa, Prabir; Fluids Team

2015-11-01

One of the most important methods of chemical enhanced oil recovery (EOR) involves the use of complex flooding schemes comprising of various layers of fluids mixed with suitable amounts of polymer or surfactant or both. The fluid flow is characterized by the spontaneous formation of complex viscous fingering patterns which is considered detrimental to oil recovery. Here we numerically study the physics of such EOR processes using a modern, hybrid method based on a combination of a discontinuous, multiscale finite element formulation and the method of characteristics. We investigate the effect of different types of heterogeneity on the fingering mechanism of these complex multiphase flows and determine the impact on oil recovery. We also study the effect of surfactants on the dynamics of the flow via reduction of capillary forces and increase in relative permeabilities. Supported by the grant NPRP 08-777-1-141 from the Qatar National Research Fund (a member of The Qatar Foundation).

Stomach Cancer Following Hodgkin Lymphoma, Testicular Cancer and Cervical Cancer: A Pooled Analysis of Three International Studies with a Focus on Radiation Effects

PubMed Central

Gilbert, Ethel S.; Curtis, Rochelle E.; Hauptmann, Michael; Kleinerman, Ruth A.; Lynch, Charles F.; Stovall, Marilyn; Smith, Susan A.; Weathers, Rita; Andersson, Michael; Dores, Graça M.; Fraumeni, Joseph F.; Fossa, Sophie D.; Hall, Per; Hodgson, David C.; Holowaty, Eric J.; Joensuu, Heikki; Johannesen, Tom B.; Langmark, Froydis; Kaijser, Magnus; Pukkala, Eero; Rajaraman, Preetha; Storm, Hans H.; Vaalavirta, Leila; van den Belt-Dusebout, Alexandra W.; Aleman, Berthe M.; Travis, Lois B.; Morton, Lindsay M.; van Leeuwen, Flora E.

2017-01-01

To further understand the risk of stomach cancer after fractionated high-dose radiotherapy, we pooled individual-level data from three recent stomach cancer case-control studies. These studies were nested in cohorts of five-year survivors of first primary Hodgkin lymphoma (HL), testicular cancer (TC) or cervical cancer (CX) from seven countries. Detailed data were abstracted from patient records and radiation doses were reconstructed to the site of the stomach cancer for cases and to the corresponding sites for matched controls. Among 327 cases and 678 controls, mean doses to the stomach were 15.3 Gy, 24.7 Gy and 1.9 Gy, respectively, for Hodgkin lymphoma, testicular cancer and cervical cancer survivors, with an overall mean dose of 10.3 Gy. Risk increased with increasing radiation dose to the stomach cancer site (P < 0.001) with no evidence of nonlinearity or of a downturn at the highest doses (≥35 Gy). The pooled excess odds ratio per Gy (EOR/Gy) was 0.091 [95% confidence interval (CI): 0.036–0.20] with estimates of 0.049 (95% CI: 0.007–0.16) for Hodgkin lymphoma, 0.27 (95% CI: 0.054–1.44) for testicular cancer and 0.096 (95% CI: −0.002–0.39) for cervical cancer (P homogeneity = 0.25). The EOR/Gy increased with time since exposure (P trend = 0.004), with an EOR/Gy of 0.38 (95% CI: 0.12–1.04) for stomach cancer occurring ≥20 years postirradiation corresponding to odds ratios of 4.8 and 10.5 at radiation doses to the stomach of 10 and 25 Gy, respectively. Of 111 stomach cancers occurring ≥20 years after radiotherapy, 63.8 (57%) could be attributed to radiotherapy. Our findings differ from those based on Japanese atomic-bomb survivors, where the overall EOR/Gy was higher and where there was no evidence of an increase with time since exposure. By pooling data from three studies, we demonstrated a clear increase in stomach cancer risk over a wide range of doses from fractionated radiotherapy with the highest risks occurring many years after exposure. These findings highlight the need to directly evaluate the health effects of high-dose fractionated radiotherapy rather than relying on the data of persons exposed at low and moderate acute doses. PMID:28118119

Off-shore enhanced oil recovery in the north sea: matching CO_2 demand and supply given uncertain market conditions

NASA Astrophysics Data System (ADS)

Compernolle, Tine; Welkenhuysen, Kris; Huisman, Kuno; Piessens, Kris; Kort, Peter

2015-04-01

Introduction CO2 enhanced oil recovery (CO2-EOR) entails the injection of CO2 in mature oil fields in order to mobilize the oil. In particular, the injected CO2 reduces the oil's viscosity and acts as a propellant, resulting in an increased oil extraction rate (Leach et al., 2011). Given uncertainty in both oil price and CO2 price under the EU ETS system, aim of this study is to analyze under which economic conditions a CO2 exchange can be established between a CO2 supplier (an electricity producer for whom CO2 is a by-product) and a CO2 user (an offshore oil company that exploits oil fields in the North Sea and needs CO2 for enhanced oil recovery). Methodology A techno-economic simulation tool, PSS IV, was developed to provide investment decision support on integrated CO2-EOR projects (Welkenhuysen et al., 2014). Until now, a fixed onshore supply of CO2 was presumed. An economic optimization model is now developed for both the CO2 producer and the CO2 user. Because net present value and discounted cash flow methods are inadequate to deal with issues like uncertainty and the irreversibility of an investment decision, the real options theory is applied (Dixit and Pindyck, 1994). The way in which cooperation between the companies can take place, will be studied using game theoretical concepts (Lukas and Welling, 2014). Economic and technical data on CO2 capture are available from the PSS database (Piessens et al., 2012). Data on EOR performance, CO2 requirements and various costs are taken from literature (BERR, 2007; Klokk et al., 2010; Pershad et al., 2012). Results/Findings It will be shown what the impact of price uncertainty is on the investment decision of the electricity producer to capture and sell CO2, and on the decision of the oil producer to make the necessary investments to inject CO2 for enhanced oil recovery. Based on these results, it will be determined under which economic conditions a CO2 exchange and transport can take place. Furthermore, also the role of the ETS system will be discussed. In an initial stage, only the CO2-price and oil price market uncertainties are considered. In a further stage, uncertainties from the supply side (technology) and EOR (geological) will be added. References BERR. 2007. Development of a CO2 transport and storage network in the North Sea: report to the North Sea Basin Task Force. Dixit A, Pindyck R (1994). Investment under Uncertainty. In, Princeton University Press. Klokk Ø, Schreiner PF, Pagès-Bernaus A, Tomasgard A (2010). Optimizing a CO2 value chain for the Norwegian Continental Shelf. Energy Policy 38(11): 6604-6614 Leach A, Mason CF, Veld Kvt (2011). Co-optimization of enhanced oil recovery and carbon sequestration. Resource Energy Econ 33(4): 893-912 Lukas E, Welling A (2014). Timing and eco(nomic) efficiency of climate-friendly investments in supply chains. Eur J Oper Res 233(2): 448-457 Pershad, H., Durusut, E., Crerar, A., Black, D., Mackay, E. & Oldern, P., 2012. Economic Impacts of CO2-enhanced oil recovery for Scotland, Final report for Scottish Enterprise. Element energy, London. Piessens, K., Welkenhuysen K., Laenen, B., Ferket, H., Nijs, W., Duerinck, J., Cochez, E., Mathieu, Ph., Valentiny, D., Baele, J.-M., Dupont, N. & Hendriks, Ch., 2012. Policy Support System for Carbon Capture and Storage and Collaboration between Belgium-the Netherlands "PSS-CCS", Final report. Belgian Science Policy Office, Research Programme Science for a Sustainable Development contracts SD/CP/04a,b & SD/CP/803, 335p. Welkenhuysen, K., Compernolle, T., Piessens, K., Ramírez, A., Rupert, J. & Swennen, R., 2014. Geological uncertainty and investment risk in CO2-enhanced oil recovery. 12th International Conference on Greenhouse Gas Control Technologies (GHGT-12), Austin, Texas, 05-09/10/2014.

Modeling CO 2 Sequestration in Saline Aquifer and Depleted Oil Reservoir To Evaluate Regional CO 2 Sequestration Potential of Ozark Plateau Aquifer System, South-Central Kansas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watney, W. Lynn

2014-09-30

1. Drilled, cored, and logged three wells to the basement and collecting more than 2,700 ft of conventional core; obtained 20 m i2 of multicomponent 3D seismic imaging and merged and reprocessed more than 125 mi 2 of existing 3D seismic data for use in modeling CO 2- EOR oil recovery and CO 2 storage in five oil fields in southern Kansas. 2. Determined the technical feasibility of injecting and sequestering CO 2 in a set of four depleted oil reservoirs in the Cutter, Pleasant Prairie South, Eubank, and Shuck fields in southwest Kansas; of concurrently recovering oil from thosemore » fields; and of quantifying the volumes of CO2 sequestered and oil recovered during the process. 3. Formed a consortium of six oil operating companies, five of which own and operate the four fields. The consortium became part of the Southwest Kansas CO 2-EOR Initiative for the purpose of sharing data, knowledge, and interest in understanding the potential for CO 2-EOR in Kansas. 4. Built a regional well database covering 30,000 mi 2 and containing stratigraphic tops from ~90,000 wells; correlated 30 major stratigraphic horizons; digitized key wells, including wireline logs and sample logs; and analyzed more than 3,000 drill stem tests to establish that fluid levels in deep aquifers below the Permian evaporites are not connected to the surface and therefore pressures are not hydrostatic. Connectivity with the surface aquifers is lacking because shale aquitards and impermeable evaporite layers consist of both halite and anhydrite. 5. Developed extensive web applications and an interactive mapping system that do the following: a. Facilitate access to a wide array of data obtained in the study, including core descriptions and analyses, sample logs, digital (LAS) well logs, seismic data, gravity and magnetics maps, structural and stratigraphic maps, inferred fault traces, earthquakes, Class I and II disposal wells, and surface lineaments. b. Provide real-time analysis of the project dataset, including automated integration and viewing of well logs, core, core analyses, brine chemistry, and stratigraphy using the Java Profile app. A cross-section app allows for the display of log data for up to four wells at a time. 6. Integrated interpretations from the project’s interactive web-based mapping system to gain insights to aid in assessing the efficacy of geologic CO 2 storage in Kansas and insights toward understanding recent seismicity to aid in evaluating induced vs. naturally occurring earthquakes. 7. Developed a digital type-log system, including web-based software to modify and refine stratigraphic nomenclature to provide stakeholders a common means for communication about the subsurface. 8. Contracted use of a nuclear magnetic resonance (NMR) log and ran it slowly to capture response and characterize larger pores common for carbonate reservoirs. Used NMR to extend core analyses to apply permeability, relative permeability to CO 2, and capillary pressure to the major rock types, each uniquely expressed as a reservoir quality index (RQI), present in the Mississippian and Arbuckle rocks. 9. Characterized and evaluated the possible role of microbes in dense brines. Used microbes to compliment H/O stable isotopes to fingerprint brine systems. Used perforation/swabbing to obtain samples from multiple hydrostratigraphic units and confirmed equivalent results using less expensive drill stem tests (DST). 10. Used an integrated approach from whole core, logs, tests, and seismic to verify and quantify properties of vuggy, brecciated, and fractured carbonate intervals. 11. Used complex geocellular static and dynamic models to evaluate regional storage capacity using large parallel processing. 12. Carbonates are complex reservoirs and CO 2-EOR needs to move to the next generation to increase effectiveness of CO 2 and efficiency and safety of the injection.« less

Composition-dependent damping and relaxation dynamics in miscible polymer blends above glass transition temperature by anelastic spectroscopy

NASA Astrophysics Data System (ADS)

Wu, Xuebang; Shang, Shuying; Xu, Qiaoling; Liu, Changsong; Zhu, Zhengang; Zhang, Guangzhao

2008-07-01

Anelastic spectroscopy is used to study the composition dependence of the damping and molecular relaxation dynamics in miscible poly(ethylene oxide) (PEO)/poly(methyl methacrylate) (PMMA) blends above the glass transition temperature. The ultrahigh damping peak of the relaxation type is shown to be associated with the liquid-liquid transition of PMMA. A higher PEO concentration leads to a higher damping performance and a lower transition temperature. The decreasing activation energy with increasing PEO concentration indicates a drastic increase in molecular mobility. Moreover, the relaxation time reveals a transition from the Vogel-Fulcher-Tamman behavior to the Arrhenius behavior due to the intermolecular guest-host interactions.

Solvent for urethane adhesives and coatings and method of use

DOEpatents

Simandl, Ronald F.; Brown, John D.; Holt, Jerrid S.

2010-08-03

A solvent for urethane adhesives and coatings, the solvent having a carbaldehyde and a cyclic amide as constituents. In some embodiments the solvent consists only of miscible constituents. In some embodiments the carbaldehyde is benzaldehyde and in some embodiments the cyclic amide is N-methylpyrrolidone (M-pyrole). An extender may be added to the solvent. In some embodiments the extender is miscible with the other ingredients, and in some embodiments the extender is non-aqueous. For example, the extender may include isopropanol, ethanol, tetrahydro furfuryl alcohol, benzyl alcohol, Gamma-butyrolactone or a caprolactone. In some embodiments a carbaldehyde and a cyclic amide are heated and used to separate a urethane bonded to a component.

Chemical Method to Improve CO{sub 2} Flooding Sweep Efficiency for Oil Recovery Using SPI-CO{sub 2} Gels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burns, Lyle D.

2009-04-14

The problem in CO{sub 2} flooding lies with its higher mobility causing low conformance or sweep efficiency. This is an issue in oilfield applications where an injected fluid or gas used to mobilize and produce the oil in a marginal field has substantially higher mobility (function of viscosity and density and relative permeability) relative to the crude oil promoting fingering and early breakthrough. Conformance is particularly critical in CO{sub 2} oilfield floods where the end result is less oil recovered and substantially higher costs related to the CO{sub 2}. The SPI-CO{sub 2} (here after called “SPI”) gel system is amore » unique silicate based gel system that offers a technically effective solution to the conformance problem with CO{sub 2} floods. This SPI gel system remains a low viscosity fluid until an external initiator (CO{sub 2}) triggers gelation. This is a clear improvement over current technologies where the gels set up as a function of time, regardless of where it is placed in the reservoir. In those current systems, the internal initiator is included in the injected fluid for water shut off applications. In this new research effort, the CO{sub 2} is an external initiator contacted after SPI gel solution placement. This concept ensures in the proper water wet reservoir environment that the SPI gel sets up in the precise high permeability path followed by the CO{sub 2}, therefore improving sweep efficiency to a greater degree than conventional systems. In addition, the final SPI product in commercial quantities is expected to be low cost over the competing systems. This Phase I research effort provided “proof of concept” that SPI gels possess strength and may be formed in a sand pack reducing the permeability to brine and CO{sub 2} flow. This SPI technology is a natural extension of prior R & D and the Phase I effort that together show a high potential for success in a Phase II follow-on project. Carbon dioxide (CO{sub 2}) is a major by-product of hydrocarbon combustion for energy, chemical and fertilizer plants. For example, coal fired power plants emit large amounts of CO{sub 2} in order to produce electrical energy. Carbon dioxide sequestration is gaining attention as concerns mount over possible global climate change caused by rising emissions of greenhouse gases. Removing the CO{sub 2} from the energy generation process would make these plants more environmentally friendly. In addition, CO{sub 2} flooding is an attractive means to enhance oil and natural gas recovery. Capture and use of the CO{sub 2} from these plants for recycling into CO{sub 2} flooding of marginal reservoirs provides a “dual use” opportunity prior to final CO{sub 2} sequestration in the depleted reservoir. Under the right pressure, temperature and oil composition conditions, CO{sub 2} can act as a solvent, cleaning oil trapped in the microscopic pores of the reservoir rock. This miscible process greatly increases the recovery of crude oil from a reservoir compared to recovery normally seen by waterflooding. An Enhanced Oil Recovery (EOR) project that uses an industrial source of CO{sub 2} that otherwise would be vented to the atmosphere has the added environmental benefit of sequestering the greenhouse gas.« less

Entanglement Length in Miscible Blends of cis-Polyisoprene and Poly(ptert-butylstyrene)

NASA Astrophysics Data System (ADS)

Watanabe, Hiroshi; Matsumiya, Yumi

In miscible polymer blends, the entanglement length is common for the components, but its changes with the composition w remain unclear. For this problem, this study analyzed viscoelastic data for miscible blends of cis-polyisoprene (PI) and poly(ptert-butylstyrene) (PtBS), considering the basic feature that the local relaxation is determined only by wPI. On the basis of this feature, a series of unentangled low- M PI/PtBS blends having various M and a given wPI were utilized as references for well-entangled high- M PI/PtBS blends having the same wPI, and the modulus data of the references were subtracted from the high- M blend data. For an optimally chosen reference, the storage modulus Ge'of the high- M blends obtained after the subtraction exhibited a clear entanglement plateau GN and the corresponding Ge' ' decreased in proportion to 1/ ω at high frequencies ω. Thus, the onset of entanglement relaxation was detected. The GN values were well described by a linear mixing rule of the entanglement length with the number fraction of Kuhn segments of the components being utilized as the averaging weight. This result, not explained by a mean-field picture of entanglement, is discussed in relation to local packing of bulky PtBS chains and skinny PI chains.

Ionic liquid compatibility in polyethylene oxide/siloxane ion gel membranes

DOE PAGES

Kusuma, Victor A.; Macala, Megan K.; Liu, Jian; ...

2018-10-02

Ion gel films were prepared by incorporating eight commercially available ionic liquids in two different cross-linked polymer matrices to evaluate their phase miscibility, gas permeability and ionic conductivity for potential applications as gas separation membranes and solid electrolyte materials. The ionic liquids cations were 1-ethyl-3-methylimidazolium, 1-ethyl-3-methylpyridinium, 1-butyl-1-methylpyrrolidinium, tributylmethylphosphonium, and butyltrimethylammonium with a common anion (bis(trifluoromethylsulfonyl)imide). In addition, ionic liquids with 1-ethyl-3-methylimidazolium cation with acetate, dicyanamide and tetrafluoroborate counterions were evaluated. The two polymers were cross-linked poly(ethylene oxide) and cross-linked poly(ethylene oxide)/siloxane copolymer. Differential scanning calorimetry, X-ray diffractometry and visual observations were performed to evaluate the ion gels’ miscibility, thermal stabilitymore » and homogeneity. Ionic liquids with the least basic anion (bis(trifluoromethylsulfonyl)imide) and aromatic cations containing acidic proton (e.g. imidazolium and pyridinium) gave the most stable and miscible ion gels. Phase stability was shown to be a function of both ionic liquid content and temperature, with phase separation observed at elevated temperatures. In conclusion, gas permeability testing with carbon dioxide and nitrogen and ionic conductivity measurements confirmed that these ionic liquids increased the gas permeability and ionic conductivity of the polymers.« less

Ionic liquid compatibility in polyethylene oxide/siloxane ion gel membranes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kusuma, Victor A.; Macala, Megan K.; Liu, Jian

Ion gel films were prepared by incorporating eight commercially available ionic liquids in two different cross-linked polymer matrices to evaluate their phase miscibility, gas permeability and ionic conductivity for potential applications as gas separation membranes and solid electrolyte materials. The ionic liquids cations were 1-ethyl-3-methylimidazolium, 1-ethyl-3-methylpyridinium, 1-butyl-1-methylpyrrolidinium, tributylmethylphosphonium, and butyltrimethylammonium with a common anion (bis(trifluoromethylsulfonyl)imide). In addition, ionic liquids with 1-ethyl-3-methylimidazolium cation with acetate, dicyanamide and tetrafluoroborate counterions were evaluated. The two polymers were cross-linked poly(ethylene oxide) and cross-linked poly(ethylene oxide)/siloxane copolymer. Differential scanning calorimetry, X-ray diffractometry and visual observations were performed to evaluate the ion gels’ miscibility, thermal stabilitymore » and homogeneity. Ionic liquids with the least basic anion (bis(trifluoromethylsulfonyl)imide) and aromatic cations containing acidic proton (e.g. imidazolium and pyridinium) gave the most stable and miscible ion gels. Phase stability was shown to be a function of both ionic liquid content and temperature, with phase separation observed at elevated temperatures. In conclusion, gas permeability testing with carbon dioxide and nitrogen and ionic conductivity measurements confirmed that these ionic liquids increased the gas permeability and ionic conductivity of the polymers.« less

Amorphous stabilization and dissolution enhancement of amorphous ternary solid dispersions: combination of polymers showing drug-polymer interaction for synergistic effects.

PubMed

Prasad, Dev; Chauhan, Harsh; Atef, Eman

2014-11-01

The purpose of this study was to understand the combined effect of two polymers showing drug-polymer interactions on amorphous stabilization and dissolution enhancement of indomethacin (IND) in amorphous ternary solid dispersions. The mechanism responsible for the enhanced stability and dissolution of IND in amorphous ternary systems was studied by exploring the miscibility and intermolecular interactions between IND and polymers through thermal and spectroscopic analysis. Eudragit E100 and PVP K90 at low concentrations (2.5%-40%, w/w) were used to prepare amorphous binary and ternary solid dispersions by solvent evaporation. Stability results showed that amorphous ternary solid dispersions have better stability compared with amorphous binary solid dispersions. The dissolution of IND from the ternary dispersion was substantially higher than the binary dispersions as well as amorphous drug. Melting point depression of physical mixtures reveals that the drug was miscible in both the polymers; however, greater miscibility was observed in ternary physical mixtures. The IR analysis confirmed intermolecular interactions between IND and individual polymers. These interactions were found to be intact in ternary systems. These results suggest that the combination of two polymers showing drug-polymer interaction offers synergistic enhancement in amorphous stability and dissolution in ternary solid dispersions. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

The Dynamics of Miscible Fluids: A Space Flight Experiment (MIDAS)

NASA Technical Reports Server (NTRS)

Maxworthy, T.; Meiburg, E.; Balasubramaniam, R.; Rashidnia, N.; Lauver, R.

2001-01-01

We propose a space flight experiment to study the dynamics of miscible interfaces. A less viscous fluid displaces one of higher viscosity within a tube. The two fluids are miscible in all proportions. An intruding "finger" forms that occupies a fraction of the tube. As time progresses diffusion at the interface combined with flow induced straining between the two fluids modifies the concentration and velocity distributions within the whole tube. Also, under such circumstances it has been proposed that the interfacial stresses could depend on the local concentration gradients (Korteweg stresses) and that the divergence of the velocity need not be zero, even though the flow is incompressible. We have obtained reasonable agreement for the tip velocity between numerical simulations (that ignored the Korteweg stress and divergence effects) and physical experiments only at high Peelet Numbers. However at moderate to low Pe agreement was poor. As one possibility we attributed this lack of agreement to the disregard of these effects. We propose a space experiment to measure the finger shape, tip velocity, and the velocity and concentration fields. From intercomparisons between the experiment and the calculations we can then extract values for the coefficients of the Korteweg stress terms and confirm or deny the importance of these stresses.

The Dynamics of Miscible Fluids: A Space Flight Experiment (MIDAS)

NASA Technical Reports Server (NTRS)

Maxworthy, T.; Meiburg, E.; Balasubramaniam, R.; Rashidnia, N.; Lauver, R.

2001-01-01

We propose a space flight experiment to study the dynamics of miscible interfaces. A less viscous fluid displaces one of higher viscosity within a tube. The two fluids are miscible in all proportions. An intruding "finger" forms that occupies a fraction of the tube. As time progresses diffusion at the interface combined with flow induced straining between the two fluids modifies the concentration and velocity distributions within the whole tube. Also, under such circumstances it has been proposed that the interfacial stresses could depend on the local concentration gradients (Korteweg stresses) and that the divergence of the velocity need not be zero, even though the flow is incompressible. We have obtained reasonable agreement for the tip velocity between numerical simulations (that ignored the Korteweg stress and divergence effects) and physical experiments only at high Peclet Numbers. However at moderate to low Pe agreement was poor. As one possibility we attributed this lack of agreement to the disregard of these effects. We propose a space experiment to measure the finger shape, tip velocity, and the velocity and concentration fields. From intercomparisons between the experiment and the calculations we can then extract values for the coefficients of the Korteweg stress terms and confirm or deny the importance of these stresses.

A Molecular-Level View of the Physical Stability of Amorphous Solid Dispersions

NASA Astrophysics Data System (ADS)

Yuan, Xiaoda

Many pharmaceutical compounds being developed in recent years are poorly soluble in water. This has led to insufficient oral bioavailability of many compounds in vitro. The amorphous formulation is one of the promising techniques to increase the oral bioavailability of these poorly water-soluble compounds. However, an amorphous drug substance is inherently unstable because it is a high energy form. In order to increase the physical stability, the amorphous drug is often formulated with a suitable polymer to form an amorphous solid dispersion. Previous research has suggested that the formation of an intimately mixed drug-polymer mixture contributes to the stabilization of the amorphous drug compound. The goal of this research is to better understand the role of miscibility, molecular interactions and mobility on the physical stability of amorphous solid dispersions. Methods were developed to detect different degrees of miscibility on nanometer scale and to quantify the extent of hydrogen-bonding interactions between the drug and the polymer. Miscibility, hydrogen-bonding interactions and molecular mobility were correlated with physical stability during a six-month period using three model systems. Overall, this research provides molecular-level insights into many factors that govern the physical stability of amorphous solid dispersions which can lead to a more effective design of stable amorphous formulations.

Miscibility of choline-substituted polyphosphazenes with PLGA and osteoblast activity on resulting blends.

PubMed

Weikel, Arlin L; Owens, Steven G; Morozowich, Nicole L; Deng, Meng; Nair, Lakshmi S; Laurencin, Cato T; Allcock, Harry R

2010-11-01

The preparation of phosphazene tissue engineering scaffolds with bioactive side groups has been accomplished using the biological buffer, choline chloride. Mixed-substituent phosphazene cyclic trimers (as model systems) and polymers with choline chloride and glycine ethyl ester, alanine ethyl ester, valine ethyl ester, or phenylalanine ethyl ester were synthesized. Two different synthetic protocols were examined. A sodium hydride mediated route resulted in polyphosphazenes with a low choline content, while a cesium carbonate mediated process produced polyphosphazenes with higher choline content. The phosphazene structures and physical properties were studied using multinuclear NMR, differential scanning calorimetry (DSC), and gel permeation chromatography (GPC) techniques. The resultant polymers were then blended with PLGA (50:50) or PLGA (85:15) and characterized by DSC analysis and scanning electron microscopy (SEM). Polymer products obtained via the sodium hydride route produced miscible blends with both ratios of PLGA, while the cesium carbonate route yielded products with reduced blend miscibility. Heterophase hydrolysis experiments in aqueous media revealed that the polymer blends hydrolyzed to near-neutral pH media (∼5.8 to 6.8). The effect of different molecular structures on cellular adhesion showed osteoblast proliferation with an elevated osteoblast phenotype expression compared to PLGA over a 21-day culture period. Copyright © 2010 Elsevier Ltd. All rights reserved.

Ternary Solar Cells Based on Two Small Molecule Donors with Same Conjugated Backbone: The Role of Good Miscibility and Hole Relay Process.

PubMed

Xiao, Liangang; Liang, Tianxiang; Gao, Ke; Lai, Tianqi; Chen, Xuebin; Liu, Feng; Russell, Thomas P; Huang, Fei; Peng, Xiaobin; Cao, Yong

2017-09-06

Ternary organic solar cells (OSCs) are very attractive for further enhancing the power conversion efficiencies (PCEs) of binary ones but still with a single active layer. However, improving the PCEs is still challenging because a ternary cell with one more component is more complicated on phase separation behavior. If the two donors or two acceptors have similar chemical structures, good miscibility can be expected to reduce the try-and-error work. Herein, we report ternary devices based on two small molecule donors with the same backbone but different substituents. Whereas both binary devices show PCEs about 9%, the PCE of the ternary cells is enhanced to 10.17% with improved fill factor and short-circuit current values and external quantum efficiencies almost in the whole absorption wavelength region from 440 to 850 nm. The same backbone enables the donors miscible at molecular level, and the donor with a higher HOMO level plays hole relay process to facilitate the charge transportation in the ternary devices. Since side-chain engineering has been well performed to tune the active materials' energy levels in OSCs, our results suggest that their ternary systems are promising for further improving the binary cells' performance although their absorptions are not complementary.

Three-dimensional Rayleigh-Taylor convection of miscible fluids in a porous medium

NASA Astrophysics Data System (ADS)

Suekane, Tetsuya; Nakanishi, Yuji; Wang, Lei

2017-11-01

Natural convection of miscible fluids in a porous medium is relevant for fields, such as geoscience and geoengineering, and for the geological storage of CO2. In this study, we use X-ray computer tomography to visualize 3D fingering structures associated with the Rayleigh-Taylor instability between miscible fluids in a porous medium. In the early stages of the onset of the Rayleigh-Taylor instability, a fine crinkling pattern gradually appears at the interface. As the wavelength and amplitude increase, descending fingers form on the interface and extend vertically downward; moreover, ascending and highly symmetric fingers form. The adjacent fingers are cylindrical in shape and coalesce to form large fingers. Fingers appearing on the interface tend to become finer with increasing Rayleigh number, which is consistent with linear perturbation theory. If the Péclet number exceeds 10, the transverse dispersion increases the finger diameter and enhances finger coalescence, strongly impacting the decay in finger number density. When mechanical dispersion is negligible, the finger-extension velocity, the mass-transfer rate, and the onset time scale with Rayleigh number. Mechanical dispersion not only reduces the onset time but also enhances mass transport, which indicates that mechanical dispersion influences the long-term dissolution process of CO2 injected into aquifers.

Behavior of CO2/water flow in porous media for CO2 geological storage.

PubMed

Jiang, Lanlan; Yu, Minghao; Liu, Yu; Yang, Mingjun; Zhang, Yi; Xue, Ziqiu; Suekane, Tetsuya; Song, Yongchen

2017-04-01

A clear understanding of two-phase fluid flow properties in porous media is of importance to CO 2 geological storage. The study visually measured the immiscible and miscible displacement of water by CO 2 using MRI (magnetic resonance imaging), and investigated the factor influencing the displacement process in porous media which were filled with quartz glass beads. For immiscible displacement at slow flow rates, the MR signal intensity of images increased because of CO 2 dissolution; before the dissolution phenomenon became inconspicuous at flow rate of 0.8mLmin -1 . For miscible displacement, the MR signal intensity decreased gradually independent of flow rates, because supercritical CO 2 and water became miscible in the beginning of CO 2 injection. CO 2 channeling or fingering phenomena were more obviously observed with lower permeable porous media. Capillary force decreases with increasing particle size, which would increase permeability and allow CO 2 and water to invade into small pore spaces more easily. The study also showed CO 2 flow patterns were dominated by dimensionless capillary number, changing from capillary finger to stable flow. The relative permeability curve was calculated using Brooks-Corey model, while the results showed the relative permeability of CO 2 slightly decreases with the increase of capillary number. Copyright © 2016 Elsevier Inc. All rights reserved.

A combined analysis of North American case-control studies of residential radon and lung cancer.

PubMed

Krewski, Daniel; Lubin, Jay H; Zielinski, Jan M; Alavanja, Michael; Catalan, Vanessa S; Field, R William; Klotz, Judith B; Létourneau, Ernest G; Lynch, Charles F; Lyon, Joseph L; Sandler, Dale P; Schoenberg, Janet B; Steck, Daniel J; Stolwijk, Jan A; Weinberg, Clarice; Wilcox, Homer B

2006-04-01

Cohort studies have consistently shown underground miners exposed to high levels of radon to be at excess risk of lung cancer, and extrapolations based on those results indicate that residential radon may be responsible for nearly 10-15% of all lung cancer deaths per year in the United States. However, case-control studies of residential radon and lung cancer have provided ambiguous evidence of radon lung cancer risks. Regardless, alpha-particle emissions from the short-lived radioactive radon decay products can damage cellular DNA. The possibility that a demonstrated lung carcinogen may be present in large numbers of homes raises a serious public health concern. Thus, a systematic analysis of pooled data from all North American residential radon studies was undertaken to provide a more direct characterization of the public health risk posed by prolonged radon exposure. To evaluate the risk associated with prolonged residential radon exposure, a combined analysis of the primary data from seven large scale case-control studies of residential radon and lung cancer risk was conducted. The combined data set included a total of 4081 cases and 5281 controls, representing the largest aggregation of data on residential radon and lung cancer conducted to date. Residential radon concentrations were determined primarily by a-track detectors placed in the living areas of homes of the study subjects in order to obtain an integrated 1-yr average radon concentration in indoor air. Conditional likelihood regression was used to estimate the excess risk of lung cancer due to residential radon exposure, with adjustment for attained age, sex, study, smoking factors, residential mobility, and completeness of radon measurements. Although the main analyses were based on the combined data set as a whole, we also considered subsets of the data considered to have more accurate radon dosimetry. This included a subset of the data involving 3662 cases and 4966 controls with a-track radon measurements within the exposure time window (ETW) 5-30 yr prior to the index date considered previously by Krewski et al. (2005). Additional restrictions focused on subjects for which a greater proportion of the ETW was covered by measured rather than imputed radon concentrations, and on subjects who occupied at most two residences. The estimated odds ratio (OR) of lung cancer generally increased with radon concentration. The OR trend was consistent with linearity (p = .10), and the excess OR (EOR) was 0.10 per Bq/m3 with 95% confidence limits (-0.01, 0.26). For the subset of the data considered previously by Krewski et al. (2005), the EOR was 0.11 (0.00, 0.28). Further limiting subjects based on our criteria (residential stability and completeness of radon monitoring) expected to improve radon dosimetry led to increased estimates of the EOR. For example, for subjects who had resided in only one or two houses in the 5-30 ETW and who had a-track radon measurements for at least 20 yr of this 25-yr period, the EOR was 0.18 (0.02, 0.43) per 100 Bq/m3. Both estimates are compatible with the EOR of 0.12 (0.02, 0.25) per 100 Bq/m3 predicted by downward extrapolation of the miner data. Collectively, these results provide direct evidence of an association between residential radon and lung cancer risk, a finding predicted by extrapolation of results from occupational studies of radon-exposed underground miners.

Assessment of microorganisms from Indonesian Oil Fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kadarwati, S.; Udiharto, M.; Rahman, M.

1995-12-31

Petroleum resources have been the mainstay of the national development in Indonesia. However, resources are being depleted after over a century of exploitation, while the demand continues to grow with the rapid economic development of the country. In facing the problem, EOR has been applied in Indonesia, such as the steamflooding project in Duri field, but a more energy efficient technology would be preferable. Therefore, MEOR has been recommended as a promising solution. Our study, aimed at finding indigenous microorganisms which can be developed for application in MEOR, has isolated microbes from some oil fields of Indonesia. These microorganisms havemore » been identified, their activities studied, and the effects of their metabolisms examined. This paper describes the research carried out by LEMIGAS in this respect, giving details on the methods of sampling, incubation, identification, and activation of the microbes as well as tests on the effects of their metabolites, with particular attention to those with potential for application in MEOR.« less

Project Columbiad: Mission to the Moon. Book 2, volume 3: Stage configuration designs; volume 4: Program plan

NASA Technical Reports Server (NTRS)

1992-01-01

The Earth Orbital Rendezvous (EOR) configuration for the piloted mission is composed of three propulsive elements in addition to the Crew Module (CM): Primary Trans-Lunar Injection (PTLI), Lunar Braking Module (LBM), and Earth Return Module (ERM). The precursor mission is also composed of three propulsive elements in addition to its surface payloads: PTLI, LBM and the Payload Landing Module (PLM). Refer to Volume 1, Section 5.1 and 5.2 for a break-up of the different stages into the four launches. A quick summary is as follows: PTLI is on Launch 1 and 3 while the LBM, PLM, and surface payloads are on Launch 2 and another LBM, ERM, and CM on Launch 4. The precursor mission is designed to be as modular as possible with the piloted mission for developmental cost considerations. The following topics are discussed: launch vehicle description; primary trans-lunar injection stage; lunar braking module; earth return module; crew module; payload landing module; and surface payload description.

Multi-scale diffuse interface modeling of multi-component two-phase flow with partial miscibility

NASA Astrophysics Data System (ADS)

Kou, Jisheng; Sun, Shuyu

2016-08-01

In this paper, we introduce a diffuse interface model to simulate multi-component two-phase flow with partial miscibility based on a realistic equation of state (e.g. Peng-Robinson equation of state). Because of partial miscibility, thermodynamic relations are used to model not only interfacial properties but also bulk properties, including density, composition, pressure, and realistic viscosity. As far as we know, this effort is the first time to use diffuse interface modeling based on equation of state for modeling of multi-component two-phase flow with partial miscibility. In numerical simulation, the key issue is to resolve the high contrast of scales from the microscopic interface composition to macroscale bulk fluid motion since the interface has a nanoscale thickness only. To efficiently solve this challenging problem, we develop a multi-scale simulation method. At the microscopic scale, we deduce a reduced interfacial equation under reasonable assumptions, and then we propose a formulation of capillary pressure, which is consistent with macroscale flow equations. Moreover, we show that Young-Laplace equation is an approximation of this capillarity formulation, and this formulation is also consistent with the concept of Tolman length, which is a correction of Young-Laplace equation. At the macroscopical scale, the interfaces are treated as discontinuous surfaces separating two phases of fluids. Our approach differs from conventional sharp-interface two-phase flow model in that we use the capillary pressure directly instead of a combination of surface tension and Young-Laplace equation because capillarity can be calculated from our proposed capillarity formulation. A compatible condition is also derived for the pressure in flow equations. Furthermore, based on the proposed capillarity formulation, we design an efficient numerical method for directly computing the capillary pressure between two fluids composed of multiple components. Finally, numerical tests are carried out to verify the effectiveness of the proposed multi-scale method.

Oxygen miscibility gap and spin glass formation in the pyrochlore Lu{sub 2}Mo{sub 2}O{sub 7}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, L.; Ritter, C.; Harrison, A.

2013-07-15

Rare earth (R) molybdate pyrochlores, R{sub 2}Mo{sub 2}O{sub 7}, are of interest as frustrated magnets. Polycrystalline samples of Lu{sub 2}Mo{sub 2}O{sub 7−x} prepared at 1600 °C display a coexistence of cubic pyrochlore phases. Rietveld fits to powder neutron diffraction data and chemical analyses show that the miscibility gap is between a stoichiometric x=0 and an oxygen-deficient x≈0.4 phase. Lu{sub 2}Mo{sub 2}O{sub 7} behaves as a spin glass material, with a divergence of field cooled and zero field cooled DC magnetic susceptibilities at a spin freezing temperature T{sub f}=16 K, that varies with frequency in AC measurements following a Vogel–Fulcher law.more » Lu{sub 2}Mo{sub 2}O{sub 6.6} is more highly frustrated spin glass and has T{sub f}=20 K. - Graphical abstract: The cubic Lu{sub 2}Mo{sub 2}O{sub 7−x} system exhibits a miscibility gap between coexisting pyrochlore phases at 1600 °C. Neutron powder diffraction refinement and chemical analysis shows that the gap separates stoichiometric x=0 and oxygen-deficient x≈0.4 phases. Lu{sub 2}Mo{sub 2}O{sub 7−x} has a frustrated spin glass ground state that is sensitive to the oxygen content. - Highlights: • The cubic Lu{sub 2}Mo{sub 2}O{sub 7−x} system has a miscibility gap between coexisting pyrochlore phases at 1600 °C. • Neutron powder diffraction shows that the gap separates x=0 and oxygen-deficient x≈0.4 phases. • Lu{sub 2}Mo{sub 2}O{sub 7−x} has a frustrated spin glass ground state that is sensitive to the oxygen content.« less

Multi-scale diffuse interface modeling of multi-component two-phase flow with partial miscibility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kou, Jisheng; Sun, Shuyu, E-mail: shuyu.sun@kaust.edu.sa; School of Mathematics and Statistics, Xi'an Jiaotong University, Xi'an 710049

2016-08-01

In this paper, we introduce a diffuse interface model to simulate multi-component two-phase flow with partial miscibility based on a realistic equation of state (e.g. Peng–Robinson equation of state). Because of partial miscibility, thermodynamic relations are used to model not only interfacial properties but also bulk properties, including density, composition, pressure, and realistic viscosity. As far as we know, this effort is the first time to use diffuse interface modeling based on equation of state for modeling of multi-component two-phase flow with partial miscibility. In numerical simulation, the key issue is to resolve the high contrast of scales from themore » microscopic interface composition to macroscale bulk fluid motion since the interface has a nanoscale thickness only. To efficiently solve this challenging problem, we develop a multi-scale simulation method. At the microscopic scale, we deduce a reduced interfacial equation under reasonable assumptions, and then we propose a formulation of capillary pressure, which is consistent with macroscale flow equations. Moreover, we show that Young–Laplace equation is an approximation of this capillarity formulation, and this formulation is also consistent with the concept of Tolman length, which is a correction of Young–Laplace equation. At the macroscopical scale, the interfaces are treated as discontinuous surfaces separating two phases of fluids. Our approach differs from conventional sharp-interface two-phase flow model in that we use the capillary pressure directly instead of a combination of surface tension and Young–Laplace equation because capillarity can be calculated from our proposed capillarity formulation. A compatible condition is also derived for the pressure in flow equations. Furthermore, based on the proposed capillarity formulation, we design an efficient numerical method for directly computing the capillary pressure between two fluids composed of multiple components. Finally, numerical tests are carried out to verify the effectiveness of the proposed multi-scale method.« less

Novel Shapes of Miscible Interfaces Observed

NASA Technical Reports Server (NTRS)

Balasubramaniam, Ramaswamy; Rashidnia, Nasser

2001-01-01

The dynamics of miscible displacements in a cylindrical tube are being investigated experimentally and numerically, with a view to understand the complex processes that occur, for example, in enhanced oil recovery, hydrology, and filtration. We have observed complex shapes of the interface between two liquids that mix with each other when the less viscous liquid is displaced by the more viscous one in a tube. A less viscous fluid that displaces a more viscous fluid is known to propagate in the form of a "finger," and a flight experiment proposed by Maxworthy et al. to investigate the miscible-interface dynamics is currently being developed by NASA. From the current theory of miscible displacements, which was developed for a porous medium satisfying Darcy's law, it can be shown that in the absence of gravity the interface between the fluids is destabilized and thus susceptible to fingering only when a more viscous fluid is displaced by a less viscous one. Therefore, if the interface is initially flat and the more viscous fluid displaces the less viscous fluid, the interface ought to be stable and remain flat. However, numerical simulations by Chen and Meiburg for such displacement in a cylindrical tube show that the interface is unstable and a finger of the more viscous fluid is indeed formed. Preliminary experiments performed at the NASA Glenn Research Center show that not only can fingering occur when the more viscous fluid displaces a less viscous one in a cylindrical tube, but also that under certain conditions the advancing finger achieves a sinuous or snakelike shape. These experiments were performed using silicone oils in a vertical pipette of small diameter. In the initial configuration, the more viscous fluid rested on top of the less viscous one, and the interface was nominally flat. A dye was added to the upper liquid for ease of observation of the interface between the fluids. The flow was initiated by draining the lower fluid from the bottom of the pipette, at speeds less than 0.1 mm/sec.

Improvement of Sweep Efficiency in Gasflooding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kishore Mohanty

2008-12-31

Miscible and near-miscible gasflooding has proven to be one of the few cost effective enhance oil recovery techniques in the past twenty years. As the scope of gas flooding is being expanded to medium viscosity oils in shallow sands in Alaska and shallower reservoirs in the lower 48, there are questions about sweep efficiency in near-miscible regions. The goal of this research is to evaluate sweep efficiency of various gas flooding processes in a laboratory model and develop numerical tools to estimate their effectiveness in the field-scale. Quarter 5-spot experiments were conducted at reservoir pressure to evaluate the sweep efficiencymore » of gas, WAG and foam floods. The quarter 5-spot model was used to model vapor extraction (VAPEX) experiments at the lab scale. A streamline-based compositional simulator and a commercial simulator (GEM) were used to model laboratory scale miscible floods and field-scale pattern floods. An equimolar mixture of NGL and lean gas is multicontact miscible with oil A at 1500 psi; ethane is a multicontact miscible solvent for oil B at pressures higher than 607 psi. WAG improves the microscopic displacement efficiency over continuous gas injection followed by waterflood in corefloods. WAG improves the oil recovery in the quarter 5-spot over the continuous gas injection followed by waterflood. As the WAG ratio increases from 1:2 to 2:1, the sweep efficiency in the 5-spot increases, from 39.6% to 65.9%. A decrease in the solvent amount lowers the oil recovery in WAG floods, but significantly higher amount of oil can be recovered with just 0.1 PV solvent injection over just waterflood. Use of a horizontal production well lowers the oil recovery over the vertical production well during WAG injection phase in this homogeneous 5-spot model. Estimated sweep efficiency decreases from 61.5% to 50.5%. In foam floods, as surfactant to gas slug size ratio increases from 1:10 to 1:1, oil recovery increases. In continuous gasflood VAPEX processes, as the distance between the injection well and production well decreases, the oil recovery and rate decreases in continuous gasflood VAPEX processes. Gravity override is observed for gas injection simulations in vertical (X-Z) cross-sections and 3-D quarter five spot patterns. Breakthrough recovery efficiency increases with the viscous-to-gravity ratio in the range of 1-100. The speed up for the streamline calculations alone is almost linear with the number of processors. The overall speed up factor is sub-linear because of the overhead time spent on the finite-difference calculation, inter-processor communication, and non-uniform processor load. Field-scale pattern simulations showed that recovery from gas and WAG floods depends on the vertical position of high permeability regions and k{sub v}/k{sub h} ratio. As the location of high permeability region moves down and k{sub v}/k{sub h} ratio decreases, oil recovery increases. There is less gravity override. The recovery from the field model is lower than that from the lab 5-spot model, but the effect of WAG ratio is similar.« less

Early opportunities of CO2 geological storage deployment in coal chemical industry in China

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wei, Ning; Li, Xiaochun; Liu, Shengnan

2014-11-12

Abstract: Carbon dioxide capture and geological storage (CCS) is regarded as a promising option for climate change mitigation; however, the high capture cost is the major barrier to large-scale deployment of CCS technologies. High-purity CO2 emission sources can reduce or even avoid the capture requirements and costs. Among these high-purity CO2 sources, certain coal chemical industry processes are very important, especially in China. In this paper, the basic characteristics of coal chemical industries in China is investigated and analyzed. As of 2013 there were more than 100 coal chemical plants in operation or in late planning stages. These emission sourcesmore » together emit 430 million tons CO2 per year, of which about 30% are emit high-purity and pure CO2 (CO2 concentration >80% and >99% respectively).Four typical source-sink pairs are studied by a techno-economic evaluation, including site screening and selection, source-sink matching, concept design, and experienced economic evaluation. The technical-economic evaluation shows that the levelized cost of a CO2 capture and aquifer storage project in the coal chemistry industry ranges from 14 USD/t to 17 USD/t CO2. When a 15USD/t CO2 tax and 15USD/t for CO2 sold to EOR are considered, the levelized cost of CCS project are negative, which suggests a net economic benefit from some of these CCS projects. This might provide China early opportunities to deploy and scale-up CCS projects in the near future.« less

Buoyancy-driven instabilities around miscible A+B→C reaction fronts: a general classification.

PubMed

Trevelyan, P M J; Almarcha, C; De Wit, A

2015-02-01

Upon contact between miscible solutions of reactants A and B along a horizontal interface in the gravity field, various buoyancy-driven instabilities can develop when an A+B→C reaction takes place and the density varies with the concentrations of the various chemicals. To classify the possible convective instability scenarios, we analyze the spatial dependence of the large time asymptotic density profiles as a function of the key parameters of the problem, which are the ratios of diffusion coefficients and of solutal expansion coefficients of species A, B, and C. We find that 62 different density profiles can develop in the reactive problem, whereas only 6 of them can be obtained in the nonreactive one.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Djabbarah, N.F.

A miscible displacement process for recovering oil from a subterranean, oil-containing formation penetrated by at least one injection well and at least one spaced-apart production well and having fluid communication between the injection and the production wells is described comprising: (a) injecting a slug of til oil into the formation through the injection well; (b) injecting a slug of a displacing fluid into the formation through the injection well, the displacing fluid being selected from the group consisting of carbon monoxide, carbon dioxide, methane, nitrogen, air, flue gas, combustion gas and mixtures thereof, the injection of the tall oil loweringmore » the minimum miscibility pressure of the displacing fluid in the formation oil; and (c) recovering the oil through the production well.« less

Osmosis-driven viscous fingering of oil-in-water emulsions

NASA Astrophysics Data System (ADS)

Liu, Ying; Rallabandi, Bhargav; Baskaran, Mrudhula; Stone, Howard

2017-11-01

Viscous fingering occurs when a low viscosity fluid invades a more viscous fluid. Fingering of two miscible fluids is more complicated than that of immiscible fluids in that there is no sharp fluid-fluid interface and diffusion occurs between the phases. We experimentally studied the fingering of two miscible fluids: an oil-in-water emulsion and a sodium chloride solution. When the concentration of sodium chloride in the water phase in the emulsion exceeds that in the sodium chloride solution, the consequent osmotic flow automatically facilitates the occurrence of the fingering. On the contrary, when the sodium chloride solution has higher concentration, the spreading of emulsion is more uniform than the case without the concentration difference. We provide a model to rationalize and quantify these observations.

Beyond Mere Automation.

DTIC Science & Technology

1981-09-01

i ont n oig 1 tte fuom nc ( w tpm i devica, eor, and tits ow rtangi the bu, and it can perfom n i and ck iga both measementandicotrlmoertsios shon...Department of Chemistry University of California, San Diego La Jolla, California , 1 Dr. A. Zirino Naval Undersea Center San Diego, California 92132 1 T’ATEI - 0 MEm~

Bimetallic Platinum-Rhodium Alloy Nanodendrites as Highly Active Electrocatalyst for the Ethanol Oxidation Reaction.

PubMed

Bai, Juan; Xiao, Xue; Xue, Yuan-Yuan; Jiang, Jia-Xing; Zeng, Jing-Hui; Li, Xi-Fei; Chen, Yu

2018-06-13

Rationally designing and manipulating composition and morphology of precious metal-based bimetallic nanostructures can markedly enhance their electrocatalytic performance, including selectivity, activity, and durability. We herein report the synthesis of bimetallic PtRh alloy nanodendrites (ANDs) with tunable composition by a facile complex-reduction synthetic method under hydrothermal conditions. The structural/morphologic features, formation mechanism, and electrocatalytic performance of PtRh ANDs are investigated thoroughly by various physical characterization and electrochemical methods. The preformed Rh crystal nuclei effectively catalyze the reduction of Pt 2+ precursor, resulting in PtRh alloy generation due to the catalytic growth and atoms interdiffusion process. The Pt atoms deposition distinctly interferes in Rh atoms deposition on Rh crystal nuclei, resulting in dendritic morphology of PtRh ANDs. For the ethanol oxidation reaction (EOR), PtRh ANDs display the chemical composition and solution pH co-dependent electrocatalytic activity. Because of the alloy effect and particular morphologic feature, Pt 1 Rh 1 ANDs with optimized composition exhibit better reactivity and stability for the EOR than commercial Pt nanocrystals electrocatalyst.

Simulations of Polarization Leakage and Ionospheric Attenuation in Visibility Measurements for the HERA and PAPER Experiments

NASA Astrophysics Data System (ADS)

Martinot, Zachary; Kohn, Saul; Aguirre, James; Washington, Immanuel; HERA Collaboration, PAPER Collaboration

2018-01-01

The HERA and PAPER experiments that aim to detect the power spectrum of the 21cm brightness temperature during the Epoch of Reionization (EoR) are planned with the expectation that foregrounds will be separated from the cosmological signal by a clearly demarcated boundary in Fourier space. Polarized foregrounds with complex frequency structure present a potential systematic as their mixing into unpolarized signal by the polarized response of an instrument's beam may be confused for the unpolarized EoR signal. There are two factors we believe will mitigate this systematic to the point that it will not impede the detection of the cosmological power spectrum in the foreground avoidance scheme. First, variation in the ionospheric plasma density observed between different days produces attenuation of the effective polarized power on the sky when visibilities are averaged coherently over many days. Second, the absolute level of polarization leakage can be suppressed through careful design of the instrument. We have performed detailed visibility simulations to investigate both effects, and present the results of these simulations for both the HERA and PAPER instruments.

Emulation of reionization simulations for Bayesian inference of astrophysics parameters using neural networks

NASA Astrophysics Data System (ADS)

Schmit, C. J.; Pritchard, J. R.

2018-03-01

Next generation radio experiments such as LOFAR, HERA, and SKA are expected to probe the Epoch of Reionization (EoR) and claim a first direct detection of the cosmic 21cm signal within the next decade. Data volumes will be enormous and can thus potentially revolutionize our understanding of the early Universe and galaxy formation. However, numerical modelling of the EoR can be prohibitively expensive for Bayesian parameter inference and how to optimally extract information from incoming data is currently unclear. Emulation techniques for fast model evaluations have recently been proposed as a way to bypass costly simulations. We consider the use of artificial neural networks as a blind emulation technique. We study the impact of training duration and training set size on the quality of the network prediction and the resulting best-fitting values of a parameter search. A direct comparison is drawn between our emulation technique and an equivalent analysis using 21CMMC. We find good predictive capabilities of our network using training sets of as low as 100 model evaluations, which is within the capabilities of fully numerical radiative transfer codes.

Micro-Employees Employment, Enhanced Oil-Recovery Improvement

NASA Astrophysics Data System (ADS)

Allahtavakoli, M.; Allahtavakoli, Y.

2009-04-01

Employment of Micro-organisms, as profitable micro-employees in improvement of Enhanced Oil Recovery (EOR), leads us to a famous method named "MEOR". Applying micro-organisms in MEOR makes it more lucrative than other EOR ways because feeding these micro-employees is highly economical and their metabolic processes require some cheap food-resources such as molasses. In addition, utilizing the local micro-organism in reservoirs will reduce the costs effectively; Furthermore these micro-organisms are safety and innocuous to some extent. In MEOR, the micro-organisms are always employed for two purposes, "Restoring pressure to reservoir" and "Decreasing Oil-Viscosity". As often as more, the former is achievable by In-Situ Mechanism or by applying the micro-organisms producing Biopolymers and the latter is also reachable by applying the micro-organisms producing Bio-surfactants. This paper as a proposal which was propounded to National Iranian Oil Company (NIOC) is an argument for studying and reviewing "Interaction between Micro-organisms and Reservoir physiochemical properties", "Biopolymer producers and Bio-Surfactant Producers", "In-Situ Mechanism", "Proposed Methods in MEOR" and their limitations.

Analysing 21cm signal with artificial neural network

NASA Astrophysics Data System (ADS)

Shimabukuro, Hayato; a Semelin, Benoit

2018-05-01

The 21cm signal at epoch of reionization (EoR) should be observed within next decade. We expect that cosmic 21cm signal at the EoR provides us both cosmological and astrophysical information. In order to extract fruitful information from observation data, we need to develop inversion method. For such a method, we introduce artificial neural network (ANN) which is one of the machine learning techniques. We apply the ANN to inversion problem to constrain astrophysical parameters from 21cm power spectrum. We train the architecture of the neural network with 70 training datasets and apply it to 54 test datasets with different value of parameters. We find that the quality of the parameter reconstruction depends on the sensitivity of the power spectrum to the different parameter sets at a given redshift and also find that the accuracy of reconstruction is improved by increasing the number of given redshifts. We conclude that the ANN is viable inversion method whose main strength is that they require a sparse extrapolation of the parameter space and thus should be usable with full simulation.

EOR by stimulated microflora

DOE Office of Scientific and Technical Information (OSTI.GOV)

Svarovskaya, L.I.; Altunina, L.K.; Rozhenkova, Z.A.

1995-12-31

A combined microbiological and physico-chemical method for EOR has been developed for flooded West Siberia oil fields with formation temperature of 45{degrees}-95{degrees}C (318-365K). Formation water includes rich and various biocenoses numbering up to 2 x 10{sup 7} cells per ml. Representatives of genera, i.e, Pseudomonas, Bacillus, Actinomyces, Micrococcus, Mycobacterium, Sarcina, etc. were found to be the most widely distributed microorganisms. The method is based on injection of systems exhibiting high oil displacing capacity and at the same time being an additional nitrous nutrient for endemic populations of microorganisms. Their injection into formation water favors biomass growth by 4-6 orders andmore » promotes syntheses of biosurfactants, biopolymers, acids, etc., and gaseous products. The features of residual oil displacement have been studied on laboratory models using a combined microbiological and physico-chemical method. A curve for the yield of residual oil is presented by two peaks. The first peak is stipulated by the washing action of oil displacement system, and the second one by the effect of metabolites produced at stimulation of biogenic processes. Oil displacement index increases by 15%-30%.« less

Improving MWA/HERA Calibration Using Extended Radio Source Models

NASA Astrophysics Data System (ADS)

Cunningham, Devin; Tasker, Nicholas; University of Washington EoR Imaging Team

2018-01-01

The formation of the first stars and galaxies in the universe is among the greatest mysteries in astrophysics. Using special purpose radio interferometers, it is possible to detect the faint 21 cm radio line emitted by neutral hydrogen in order to characterize the Epoch of Reionization (EoR) and the formation of the first stars and galaxies. We create better models of extended radio sources by reducing component number of deconvolved Murchison Widefield Array (MWA) data by up to 90%, while preserving real structure and flux information. This real structure is confirmed by comparisons to observations of the same extended radio sources from the TIFR GMRT Sky Survey (TGSS) and NRAO VLA Sky Survey (NVSS), which detect at a similar frequency range as the MWA. These sophisticated data reduction techniques not only offer improvements to the calibration of the MWA, but also hold applications for the future sky-based calibration of the Hydrogen Epoch of Reionization Array (HERA). This has the potential to reduce noise in the power spectra from these instruments, and consequently provide a deeper view into the window of EoR.

Polarized Power Spectra from HERA-19 Commissioning Data: Instrument Stability

NASA Astrophysics Data System (ADS)

Fox Fortino, Austin; Chichura, Paul; Igarashi, Amy; Kohn, Saul; Aguirre, James; HERA Collaboration

2018-01-01

The Epoch of Reionization (EoR) is a key period in the universe’s history, containing the formation of the first galaxies and large scale structures. Foreground emission is the limiting factor in detecting the 21 cm emission from the Epoch of Reionization (EoR). The HERA-19 low frequency radio interferometer aims to reduce the obfuscation from the foreground emission with its dish shaped antennae. We generate polarized 2D (cylindrically averaged) power spectra from seven days of observation from the HERA-19 2016 observation season in each of the four Stokes parameters I, Q, U, and V. These power spectra serve as a potent diagnostic tool that allow us to understand the instrument stability by comparison between nominally redundant baselines, and between observations of nominally the same astrophysical sky on successive days. The power spectra are expected to vary among nominally redundant measurements due to ionosphere fluctuations and thermal changes in the electronics and instrument beam patterns, as well as other factors. In this work we investigate the stability over time of these polarized power spectra, and use them to quantify the variation due to these effects.

Pore-scale modeling of moving contact line problems in immiscible two-phase flow

NASA Astrophysics Data System (ADS)

Kucala, Alec; Noble, David; Martinez, Mario

2016-11-01

Accurate modeling of moving contact line (MCL) problems is imperative in predicting capillary pressure vs. saturation curves, permeability, and preferential flow paths for a variety of applications, including geological carbon storage (GCS) and enhanced oil recovery (EOR). Here, we present a model for the moving contact line using pore-scale computational fluid dynamics (CFD) which solves the full, time-dependent Navier-Stokes equations using the Galerkin finite-element method. The MCL is modeled as a surface traction force proportional to the surface tension, dependent on the static properties of the immiscible fluid/solid system. We present a variety of verification test cases for simple two- and three-dimensional geometries to validate the current model, including threshold pressure predictions in flows through pore-throats for a variety of wetting angles. Simulations involving more complex geometries are also presented to be used in future simulations for GCS and EOR problems. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Measurement and Visualization of Tight Rock Exposed to CO2 Using NMR Relaxometry and MRI

PubMed Central

Wang, Haitao; Lun, Zengmin; Lv, Chengyuan; Lang, Dongjiang; Ji, Bingyu; Luo, Ming; Pan, Weiyi; Wang, Rui; Gong, Kai

2017-01-01

Understanding mechanisms of oil mobilization of tight matrix during CO2 injection is crucial for CO2 enhanced oil recovery (EOR) and sequestration engineering design. In this study exposure behavior between CO2 and tight rock of the Ordos Basin has been studied experimentally by using nuclear magnetic resonance transverse relaxation time (NMR T2) spectrum and magnetic resonance imaging (MRI) under the reservoir pressure and temperature. Quantitative analysis of recovery at the pore scale and visualization of oil mobilization are achieved. Effects of CO2 injection, exposure times and pressure on recovery performance have been investigated. The experimental results indicate that oil in all pores can be gradually mobilized to the surface of rock by CO2 injection. Oil mobilization in tight rock is time-consuming while oil on the surface of tight rock can be mobilized easily. CO2 injection can effectively mobilize oil in all pores of tight rock, especially big size pores. This understanding of process of matrix exposed to CO2 could support the CO2 EOR in tight reservoirs. PMID:28281697

Study of Synthesis Polyethylene glycol oleate Sulfonated as an Anionic Surfactant for Enhanced Oil Recovery (EOR)

NASA Astrophysics Data System (ADS)

Sampora, Yulianti; Juwono, Ariadne L.; Haryono, Agus; Irawan, Yan

2017-11-01

Mechanical Enhanced Oil Recovery (EOR) through chemical injection is using an anionic surfactant to improve the recovery of oil residues, particularly in a reservoir area that has certain characteristics. This case led the authors to conduct research on the synthesis of an anionic surfactant based on oleic acid and polyethylene glycol 400 that could be applied as a chemical injection. In this work, we investigate the sulfonation of Polyethylene glycol oleate (PDO) in a sulfuric acid agent. PDO in this experiment was derived from Indonesian palm oil. Variation of mole reactant and reaction time have been studied. The surfactant has been characterized by measuring the interfacial tension, acid value, ester value, saponification value, iodine value, Fourier Transform Infrared (FTIR), and particle size analyzer. There is a new peak at 1170-1178 cm-1 indicating that S=O bond has formed. PDO sulfonate exhibits good surface activity due to interfacial tension of 0,003 mN/m. Thus, polyethylene glycol oleate sulfonate was successfully synthesized and it could be useful as a novel an anionic surfactant.

SURFACTANT BASED ENHANCED OIL RECOVERY AND FOAM MOBILITY CONTROL

DOE Office of Scientific and Technical Information (OSTI.GOV)

George J. Hirasaki; Clarence A. Miller; Gary A. Pope

2004-07-01

Surfactant flooding has the potential to significantly increase recovery over that of conventional waterflooding. The availability of a large number of surfactants makes it possible to conduct a systematic study of the relation between surfactant structure and its efficacy for oil recovery. Also, the addition of an alkali such as sodium carbonate makes possible in situ generation of surfactant and significant reduction of surfactant adsorption. In addition to reduction of interfacial tension to ultra-low values, surfactants and alkali can be designed to alter wettability to enhance oil recovery. An alkaline surfactant process is designed to enhance spontaneous imbibition in fractured,more » oil-wet, carbonate formations. It is able to recover oil from dolomite core samples from which there was no oil recovery when placed in formation brine. Mobility control is essential for surfactant EOR. Foam is evaluted to improve the sweep efficiency of surfactant injected into fractured reservoirs. UTCHEM is a reservoir simulator specially designed for surfactant EOR. A dual-porosity version is demonstrated as a potential scale-up tool for fractured reservoirs.« less

Liquidus Projections of Bi-Se-Ga and Bi-Se-Te Ternary Systems

NASA Astrophysics Data System (ADS)

Lin, Po-han; Chen, Sinn-wen; Hwang, Jenn-dong; Chu, Hsu-shen

2016-12-01

This study determines the liquidus projections of both Bi-Se-Ga and Bi-Se-Te ternary systems which are constituent ternary systems of promising Bi-Se-Te-Ga thermoelectric materials. Ternary Bi-Se-Ga and Bi-Se-Te alloys are prepared. Their primary solidification phases are experimentally determined, and thermal analysis experiments are carried out. The liquidus projections are determined based on the ternary experimental results and phase diagrams of constituent binary systems. The Bi-Se-Ga system includes seven primary solidification phases, Bi, Ga, GaSe, Ga2Se3, Se, Bi2Se3, and (Bi2)n(Bi2Se3)m. In the Bi-Se-Te system, there are five primary solidification phases, Bi, (Bi2)n(Bi2Te3)m, Bi2(Se,Te)3, (Se,Te), and (Bi2)n(Bi2Se3)m. Both the (Bi2)n(Bi2Te3)m and (Bi2)n(Bi2Se3)m phases are not a single phase, but a collection of series undetermined phases. Large miscibility gaps are observed in the Bi-Se-Ga system. The temperatures of the invariant reactions, Liquid + Bi + GaSe = Ga and Liquid + Ga2Se3 = Bi + GaSe, are at 495 K (222 °C) and 533 K (260 °C), respectively.

Diffusion and recrystallization of B implanted in crystalline and pre-amorphized Ge in the presence of F

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsu, William, E-mail: william.hsu@utexas.edu; Kim, Taegon; Chou, Harry

2016-07-07

Although the diffusion control and dopant activation of Ge p-type junctions are straightforward when using B{sup +} implantation, the use of the heavier BF{sub 2}{sup +} ions or even BF{sup +} is still favored in terms of shallow junction formation and throughput—because implants can be done at higher energies, which can give higher beam currents and beam stability—and thus the understanding of the effect of F co-doping becomes important. In this work, we have investigated diffusion and end-of-range (EOR) defect formation for B{sup +}, BF{sup +}, and BF{sub 2}{sup +} implants in crystalline and pre-amorphized Ge, employing rapid thermal annealingmore » at 600 °C and 800 °C for 10 s. It is demonstrated that the diffusion of B is strongly influenced by the temperature, the presence of F, and the depth of amorphous/crystalline interface. The B and F diffusion profiles suggest the formation of B–F complexes and enhanced diffusion by interaction with point defects. In addition, the strong chemical effect of F is found only for B in Ge, while such an effect is vanishingly small for samples implanted with F alone, or co-implanted with P and F, as evidenced by the high residual F concentration in the B-doped samples after annealing. After 600 °C annealing for 10 s, interstitial-induced compressive strain was still observed in the EOR region for the sample implanted with BF{sup +}, as measured by X-ray diffraction. Further analysis by cross-sectional transmission electron microscopy showed that the {311} interstitial clusters are the majority type of EOR defects. The impact of these {311} defects on the electrical performance of Ge p{sup +}/n junctions formed by BF{sup +} implantation was evaluated.« less

The Impact of Diffusion Tensor Imaging Fiber Tracking of the Corticospinal Tract Based on Navigated Transcranial Magnetic Stimulation on Surgery of Motor-Eloquent Brain Lesions.

PubMed

Raffa, Giovanni; Conti, Alfredo; Scibilia, Antonino; Cardali, Salvatore Massimiliano; Esposito, Felice; Angileri, Filippo Flavio; La Torre, Domenico; Sindorio, Carmela; Abbritti, Rosaria Viola; Germanò, Antonino; Tomasello, Francesco

2017-11-29

Navigated transcranial magnetic stimulation (nTMS) enables preoperative mapping of the motor cortex (M1). The combination of nTMS with diffusion tensor imaging fiber tracking (DTI-FT) of the corticospinal tract (CST) has been described; however, its impact on surgery of motor-eloquent lesions has not been addressed. To analyze the impact of nTMS-based mapping on surgery of motor-eloquent lesions. In this retrospective case-control study, we reviewed the data of patients operated for suspected motor-eloquent lesions between 2012 and 2015. The patients underwent nTMS mapping of M1 and, from 2014, nTMS-based DTI-FT of the CST. The impact on the preoperative risk/benefit analysis, surgical strategy, craniotomy size, extent of resection (EOR), and outcome were compared with a control group. We included 35 patients who underwent nTMS mapping of M1 (group A), 35 patients who also underwent nTMS-based DTI-FT of the CST (group B), and a control group composed of 35 patients treated without nTMS (group C). The patients in groups A and B received smaller craniotomies (P = .01; P = .001), had less postoperative seizures (P = .02), and a better postoperative motor performance (P = .04) and Karnofsky Performance Status (P = .009) than the controls. Group B exhibited an improved risk/benefit analysis (P = .006), an increased EOR of nTMS-negative lesions in absence of preoperative motor deficits (P = .01), and less motor and Karnofsky Performance Status worsening in case of preoperative motor deficits (P = .02, P = .03) than group A. nTMS-based mapping enables a tailored surgical approach for motor-eloquent lesions. It may improve the risk/benefit analysis, EOR and outcome, particularly when nTMS-based DTI-FT is performed. Copyright © 2017 by the Congress of Neurological Surgeons

Ternary Pt9RhFex Nanoscale Alloys as Highly Efficient Catalysts with Enhanced Activity and Excellent CO-Poisoning Tolerance for Ethanol Oxidation.

PubMed

Wang, Peng; Yin, Shibin; Wen, Ying; Tian, Zhiqun; Wang, Ningzhang; Key, Julian; Wang, Shuangbao; Shen, Pei Kang

2017-03-22

To address the problems of high cost and poor stability of anode catalysts in direct ethanol fuel cells (DEFCs), ternary nanoparticles Pt 9 RhFe x (x = 1, 3, 5, 7, and 9) supported on carbon powders (XC-72R) have been synthesized via a facile method involving reduction by sodium borohydride followed by thermal annealing in N 2 at ambient pressure. The catalysts are physically characterized by X-ray diffraction, scanning transmission electron microscopy, and X-ray photoelectron spectroscopy, and their catalytic performance for the ethanol oxidation reaction (EOR) is evaluated by cyclic and linear scan voltammetry, CO-stripping voltammograms, and chronopotentiometry. All the Pt 9 RhFe x /C catalysts of different atomic ratios produce high EOR catalytic activity. The catalyst of atomic ratio composition 9:1:3 (Pt/Rh/Fe) has the highest activity and excellent CO-poisoning tolerance. Moreover, the enhanced EOR catalytic activity on Pt 9 RhFe 3 /C when compared to Pt 9 Rh/C, Pt 3 Fe/C, and Pt/C clearly demonstrates the presence of Fe improves catalytic performance. Notably, the onset potential for CO oxidation on Pt 9 RhFe 3 /C (0.271 V) is ∼55, 75, and 191 mV more negative than on Pt 9 Rh/C (0.326 V), Pt 3 Fe/C (0.346 V), and Pt/C (0.462 V), respectively, which implies the presence of Fe atoms dramatically improves CO-poisoning tolerance. Meanwhile, compared to the commercial PtRu/C catalyst, the peak potential on Pt 9 RhFe 3 /C for CO oxidation was just slightly changed after several thousand cycles, which shows high stability against the potential cycling. The possible mechanism by which Fe and Rh atoms facilitate the observed enhanced performance is also considered herein, and we conclude Pt 9 RhFe 3 /C offers a promising anode catalyst for direct ethanol fuel cells.

Citronelle Dome: A giant opportunity for multizone carbon storage and enhanced oil recovery in the Mississippi Interior Salt Basin of Alabama

USGS Publications Warehouse

Esposito, R.A.; Pashin, J.C.; Walsh, P.M.

2008-01-01

The Citronelle Dome is a giant, salt-cored anticline in the eastern Mississippi Interior Salt Basin of southern Alabama that is located near several large-scale, stationary, carbon-emitting sources in the greater Mobile area. The dome forms an elliptical, four-way structural closure containing opportunities for CO2-enhanced oil recovery (CO2-EOR) and large-capacity saline reservoir CO2 sequestration. The Citronelle oil field, located on the crest of the dome, has produced more than 169 million bbl of 42-46?? API gravity oil from sandstone bodies in the Lower Cretaceous Rodessa Formation. The top seal for the oil accumulation is a thick succession of shale and anhydrite, and the reservoir is underfilled such that oil-water contacts are typically elevated 30-60 m (100-200 ft) above the structural spill point. Approximately 31-34% of the original oil in place has been recovered by primary and secondary methods, and CO2-EOR has the potential to increase reserves by up to 20%. Structural contour maps of the dome demonstrate that the area of structural closure increases upward in section. Sandstone units providing prospective carbon sinks include the Massive and Pilot sands of the lower Tuscaloosa Group, as well as several sandstone units in the upper Tuscaloosa Group and the Eutaw Formation. Many of these sandstone units are characterized by high porosity and permeability with low heterogeneity. The Tuscaloosa-Eutaw interval is capped by up to 610 m (2000 ft) of chalk and marine shale that are proven reservoir seals in nearby oil fields. Therefore, the Citronelle Dome can be considered a major geologic sink where CO2 can be safely stored while realizing the economic benefits associated with CO2-EOR. Copyright ?? 2008. The American Association of Petroleum Geologists/Division of Environmental Geosciences. All rights reserved.

Influence of * OH adsorbates on the potentiodynamics of the CO 2 generation during the electro-oxidation of ethanol

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Guangxing; Namin, Lida M.; Aaron Deskins, N.

Direct ethanol fuel cells (DEFCs) are a promising technology for the generation of electricity via the direct conversion of ethanol into CO2, showing higher thermodynamic efficiency and volumetric energy density than hydrogen fuel cells. However, implementation of DEFCs is hampered by the low CO2 selectivity during the ethanol oxidation reaction (EOR). Comprehensive understanding of the electro-kinetics and reaction pathways of CO2 generation via CC bond-breaking is not only a fundamental question for electro-catalysis, but also a key technological challenge since practical implementation of DEFC technology is contingent on its ability to selectively oxidize ethanol into CO2 to achieve exceptional energymore » density through 12-electron transfer reaction. Here, we present comprehensive in situ potentiodynamics studies of CO2 generation during the EOR on Pt, Pt/SnO2 and Pt/Rh/SnO2 catalysts using a house-made electrochemical cell equipped with a CO2 microelectrode. Highly sensitive CO2 measurements enable the real time detection of the partial pressure of CO2 during linear sweep voltammetry measurements, through which electro-kinetics details of CO2 generation can be obtained. In situ CO2 measurements provide the mechanistic understanding of potentiodynamics of the EOR, particularly the influence of *OH adsorbates on CO2 generation rate and selectivity. Density functional theory (DFT) simulations of Pt, Pt/SnO2, and Pt/Rh/SnO2 surfaces clarify reaction details over these catalysts. Our results show that at low potentials, inadequate *OH adsorbates impair the removal of reaction intermediates, and thus Pt/Rh/SnO2 exhibited the best performance toward CO2 generation, while at high potentials, Rh sites were overwhelmingly occupied (poisoned) by *OH adsorbates, and thus Pt/SnO2 exhibited the best performance toward CO2 generation.« less

Influence of *OH adsorbates on the potentiodynamics of the CO 2 generation during the electro-oxidation of ethanol

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Guangxing; Namin, Lida M.; Aaron Deskins, N.

Direct ethanol fuel cells (DEFCs) are a promising technology for the generation of electricity via the direct conversion of ethanol into CO 2, showing higher thermodynamic efficiency and volumetric energy density than hydrogen fuel cells. However, implementation of DEFCs is hampered by the low CO 2 selectivity during the ethanol oxidation reaction (EOR). Comprehensive understanding of the electro-kinetics and reaction pathways of CO 2 generation via CC bond-breaking is not only a fundamental question for electro-catalysis, but also a key technological challenge since practical implementation of DEFC technology is contingent on its ability to selectively oxidize ethanol into CO 2more » to achieve exceptional energy density through 12-electron transfer reaction. Here, we present comprehensive in situ potentiodynamics studies of CO 2 generation during the EOR on Pt, Pt/SnO 2 and Pt/Rh/SnO 2 catalysts using a house-made electrochemical cell equipped with a CO 2 microelectrode. Highly sensitive CO 2 measurements enable the real time detection of the partial pressure of CO 2 during linear sweep voltammetry measurements, through which electro-kinetics details of CO 2 generation can be obtained. In situ CO 2 measurements provide the mechanistic understanding of potentiodynamics of the EOR, particularly the influence of *OH adsorbates on CO 2 generation rate and selectivity. Density functional theory (DFT) simulations of Pt, Pt/SnO 2, and Pt/Rh/SnO 2 surfaces clarify reaction details over these catalysts. Our results show that at low potentials, inadequate *OH adsorbates impair the removal of reaction intermediates, and thus Pt/Rh/SnO 2 exhibited the best performance toward CO 2 generation, while at high potentials, Rh sites were overwhelmingly occupied (poisoned) by *OH adsorbates, and thus Pt/SnO 2 exhibited the best performance toward CO 2 generation.« less

Prediction of Phase Behavior of Spray-Dried Amorphous Solid Dispersions: Assessment of Thermodynamic Models, Standard Screening Methods and a Novel Atomization Screening Device with Regard to Prediction Accuracy

PubMed Central

Chavez, Pierre-François; Meeus, Joke; Robin, Florent; Schubert, Martin Alexander; Somville, Pascal

2018-01-01

The evaluation of drug–polymer miscibility in the early phase of drug development is essential to ensure successful amorphous solid dispersion (ASD) manufacturing. This work investigates the comparison of thermodynamic models, conventional experimental screening methods (solvent casting, quench cooling), and a novel atomization screening device based on their ability to predict drug–polymer miscibility, solid state properties (Tg value and width), and adequate polymer selection during the development of spray-dried amorphous solid dispersions (SDASDs). Binary ASDs of four drugs and seven polymers were produced at 20:80, 40:60, 60:40, and 80:20 (w/w). Samples were systematically analyzed using modulated differential scanning calorimetry (mDSC) and X-ray powder diffraction (XRPD). Principal component analysis (PCA) was used to qualitatively assess the predictability of screening methods with regards to SDASD development. Poor correlation was found between theoretical models and experimentally-obtained results. Additionally, the limited ability of usual screening methods to predict the miscibility of SDASDs did not guarantee the appropriate selection of lead excipient for the manufacturing of robust SDASDs. Contrary to standard approaches, our novel screening device allowed the selection of optimal polymer and drug loading and established insight into the final properties and performance of SDASDs at an early stage, therefore enabling the optimization of the scaled-up late-stage development. PMID:29518936

Miscibility and interaction between 1-alkanol and short-chain phosphocholine in the adsorbed film and micelles.

PubMed

Takajo, Yuichi; Matsuki, Hitoshi; Kaneshina, Shoji; Aratono, Makoto; Yamanaka, Michio

2007-09-01

The miscibility and interaction of 1-hexanol (C6OH) and 1-heptanol (C7OH) with 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC) in the adsorbed films and micelles were investigated by measuring the surface tension of aqueous C6OH-DHPC and aqueous C7OH-DHPC solutions. The surface density, the mean molecular area, the composition of the adsorbed film, and the excess Gibbs energy of adsorption g(H,E), were estimated. Further, the critical micelle concentration of the mixtures was determined from the surface tension versus molality curves; the micellar composition was calculated. The miscibility of the 1-alkanols and DHPC molecules in the adsorbed film and micelles was examined using the phase diagram of adsorption (PDA) and that of micellization (PDM). The PDA and the composition dependence of g(H,E) indicated the non-ideal mixing of the 1-alkanols and DHPC molecules due to the attractive interaction between the molecules in the adsorbed film, while the PDM indicated that the 1-alkanol molecules were not incorporated in the micelles within DHPC rich region. The dependence of the mean molecular area of the mixtures on the surface composition suggested that the packing property of the adsorbed film depends on the chain length of 1-alkanol: C6OH expands the DHPC adsorbed film more than C7OH.

Richtmyer-Meshkov instability experiments of miscible and immiscible incompressible fluids

NASA Astrophysics Data System (ADS)

Krivets, Vitaliy; Holt, Brason; Mokler, Matthew; Jacobs, Jeffrey

2017-11-01

Experiments were conducted in a 3 m tall vertical drop tower setup. A flat interface separating two liquids of differing density is formed in the Plexiglas tank with the heavier fluid in the bottom and the lighter one on top. Two liquids pairs were utilized, one - miscible (isopropyl alcohol and a calcium nitrate water mixture) and the other immiscible (silicone oil with the same heavy liquid), both with Atwood near 0.2. The tank is mounted on a rail mounted sled at 2 m initial height where an initial perturbation is generated using vertical periodic motion with 10 Hz frequency and 1 mm displacement, thus producing 3D interfacial waves. An impulsive acceleration, with approximately 100g magnitude, is imparted to the sled by a rail mounted weight released and allowed to fall, impacting the sled from above. Both weight and sled then travel freely down the rails where they are smoothly decelerated at the bottom of drop tower by magnetic brakes. PLIF is used to visualize mixing process by seeding fluorescein in the bottom fluid and illuminating using laser diode from above forming thin vertical sheet. The resulting fluorescent image sequences are captured using a digital camera mounted to the sled operating at a 100 Hz framing rate. Comparisons of the measured growth of the mixing zone for both immiscible and miscible liquid combinations with theoretical models are presented.

Molecular Dynamics Simulation of Amorphous Hydroxypropylmethylcellulose and Its Mixtures With Felodipine and Water.

PubMed

Xiang, Tian-Xiang; Anderson, Bradley D

2017-03-01

Understanding drug-polymer molecular interactions, their miscibility, supersaturation potential, and the effects of water uptake may be invaluable for selecting amorphous polymer dispersions that can maximize the oral bioavailability of poorly water-soluble drugs. Molecular dynamics simulations were performed using a model for hydroxypropylmethylcellulose (HPMC) resembling the substitution patterns found experimentally. HPMC at low and high water contents (0.9%-23.0% wt/wt) and mixtures with a hydrophobic drug, felodipine (FEL), were constructed. T g values and densities after ∼30 ns aging at 298 K were close to published results. Except for hydrogen bonds (HBs) between the 5-O- and a 3-OH group in a neighboring repeat unit, HPMC oxygen atoms have a low HB probability (p < 0.1) perhaps due to shielding by surrounding substituents. Water molecules tend to be isolated at low water content while clusters were prevalent at ≥10.7% water. The Flory-Huggins FEL-HPMC interaction parameter (-0.20 ± 0.07) predicts complete miscibility at all HPMC compositions, in agreement with experiments. However, HBs between the FEL-N-H and HPMC favoring miscibility are disrupted with increasing water. Apparent diffusion coefficients versus water content were generated for water and FEL and a theory for the non-Einsteinian nature of water diffusion is proposed. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

An experimental study of non-isothermal miscible displacements in a Hele-Shaw cell

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nagatsu, Yuichiro; Fujita, Norihito; Kato, Yoshihito

Non-isothermal miscible displacements in a radial Hele-Shaw cell were experimentally investigated using a scheme in which room temperature liquids of relatively high viscosity were displaced by high-temperature (80 C), less-viscous liquids. Fundamental characteristics have been presented regarding how the effect of a non-isothermal field on miscible displacement patterns varies in terms of factors such as the viscosity ratio of the more- and less-viscous liquids at 20 C, M{sub 20}, the rate of an increase in the pattern's area, R, and the gap width of the cell, b. The concept of area density was used to quantitatively evaluate the effect ofmore » the non-isothermal fields on the patterns. We have found that the effect of the non-isothermal field on the patterns does not monotonically vary with M{sub 20} and b. In contrast, it increases with R in the present experimental condition. The experimental results can be explained by introducing an assumption in which heat is transferred mainly to the plates of the cell, in other words, the temperature of the more-viscous liquid remains constant, whereas that of the less-viscous liquid spatiotemporally decreases and the viscosity of it increases along with the temperature decrease. Visualization of non-isothermal field in the cell has been done by means of a thermo sheet and the results support the assumption mentioned above. (author)« less

Pseudolatex preparation using a novel emulsion-diffusion process involving direct displacement of partially water-miscible solvents by distillation.

PubMed

Quintanar-Guerrero, D; Allémann, E; Fessi, H; Doelker, E

1999-10-25

Pseudolatexes were obtained by a new process based on an emulsification-diffusion technique involving partially water-miscible solvents. The preparation method consisted of emulsifying an organic solution of polymer (saturated with water) in an aqueous solution of a stabilizing agent (saturated with solvent) using conventional stirrers, followed by direct solvent distillation. The technique relies on the rapid displacement of the solvent from the internal into the external phase which thereby provokes polymer aggregation. Nanoparticle formation is believed to occur because rapid solvent diffusion produces regions of local supersaturation near the interface, and nanoparticles are formed due to the ensuing interfacial phase transformations and polymer aggregation that occur in these interfacial domains. Using this method, it was possible to prepare pseudolatexes of biodegradable and non-biodegradable polymers such as poly(D,L-lactic acid) and poly(epsilon-caprolactone), Eudragit E, cellulose acetate phthalate, cellulose acetate trimellitate using ethyl acetate or 2-butanone as partially water-miscible solvents and poly(vinyl alcohol) or poloxamer 407 as stabilizing agent. A transition from nano- to microparticles was observed at high polymer concentrations. At concentrations above 30% w/v of Eudragit E in ethyl acetate or cellulose acetate phthalate in 2-butanone only microparticles were obtained. This behaviour was attributed to decreased transport of polymer molecules into the aqueous phase.

Effect of stirring on the safety of flammable liquid mixtures.

PubMed

Liaw, Horng-Jang; Gerbaud, Vincent; Chen, Chan-Cheng; Shu, Chi-Min

2010-05-15

Flash point is the most important variable employed to characterize fire and explosion hazard of liquids. The models developed for predicting the flash point of partially miscible mixtures in the literature to date are all based on the assumption of liquid-liquid equilibrium. In real-world environments, however, the liquid-liquid equilibrium assumption does not always hold, such as the collection or accumulation of waste solvents without stirring, where complete stirring for a period of time is usually used to ensure the liquid phases being in equilibrium. This study investigated the effect of stirring on the flash-point behavior of binary partially miscible mixtures. Two series of partially miscible binary mixtures were employed to elucidate the effect of stirring. The first series was aqueous-organic mixtures, including water+1-butanol, water+2-butanol, water+isobutanol, water+1-pentanol, and water+octane; the second series was the mixtures of two flammable solvents, which included methanol+decane, methanol+2,2,4-trimethylpentane, and methanol+octane. Results reveal that for binary aqueous-organic solutions the flash-point values of unstirred mixtures were located between those of the completely stirred mixtures and those of the flammable component. Therefore, risk assessment could be done based on the flammable component flash-point value. However, for the assurance of safety, it is suggested to completely stir those mixtures before handling to reduce the risk. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Dependence on sphere size of the phase behavior of mixtures of rods and spheres

NASA Astrophysics Data System (ADS)

Urakami, Naohito; Imai, Masayuki

2003-07-01

By the addition of chondroitin sulfate (Chs) to the aqueous suspension of tobacco mosaic virus (TMV), the aggregation of TMV occurs at very dilute TMV concentration compared with the addition of polyethylene oxide (PEO). The difference of physical behavior between Chs and PEO is the chain conformation in solution. The Chs chain has a semirigid nature, whereas the PEO chain has a flexible nature. In this study, the Chs and PEO chains are simplified to spherical particles having different size, and we use the spherocylinder model for TMV particle. The effect of the sphere size on the phase behaviors in the mixtures of rods and spheres is investigated by Monte Carlo simulations. By the addition of small spheres, the system transforms from the miscible isotropic phase to the miscible nematic phase. On the other hand, by the addition of large spheres, the system changes from the miscible isotropic phase to the immiscible nematic phase through the immiscible isotropic phase. The different phase behaviors between the small and the large spheres originate from the difference of overlapping volume of the depletion zone. In addition, we perform the Monte Carlo simulations in the case that semirigid chains are used as the Chs chain models. The same phase behaviors are observed as the mixtures of rods and large spheres. Thus the sphere model captures the phase behaviors of rod and polymer mixture systems.

Effect of poly(ethylene oxide) homopolymer and two different poly(ethylene oxide-b-poly(propylene oxide)-b-poly(ethylene oxide) triblock copolymers on morphological, optical, and mechanical properties of nanostructured unsaturated polyester.

PubMed

Builes, Daniel H; Hernández-Ortiz, Juan P; Corcuera, Ma Angeles; Mondragon, Iñaki; Tercjak, Agnieszka

2014-01-22

Novel nanostructured unsaturated polyester resin-based thermosets, modified with poly(ethylene oxide) (PEO), poly(propylene oxide) (PPO), and two poly(ethylene oxide-b-propylene oxide-b-ethylene oxide) block copolymers (BCP), were developed and analyzed. The effects of molecular weights, blocks ratio, and curing temperatures on the final morphological, optical, and mechanical properties were reported. The block influence on the BCP miscibility was studied through uncured and cured mixtures of unsaturated polyester (UP) resins with PEO and PPO homopolymers having molecular weights similar to molecular weights of the blocks of BCP. The final morphology of the nanostructured thermosetting systems, containing BCP or homopolymers, was investigated, and multiple mechanisms of nanostructuration were listed and explained. By considering the miscibility of each block before and after curing, it was determined that the formation of the nanostructured matrices followed a self-assembly mechanism or a polymerization-induced phase separation mechanism. The miscibility between PEO or PPO blocks with one of two phases of UP matrix was highlighted due to its importance in the final thermoset properties. Relationships between the final morphology and thermoset optical and mechanical properties were examined. The mechanisms and physics behind the morphologies lead toward the design of highly transparent, nanostructured, and toughened thermosetting UP systems.

Miscibility as a factor for component crystallization in multisolute frozen solutions.

PubMed

Izutsu, Ken-Ichi; Shibata, Hiroko; Yoshida, Hiroyuki; Goda, Yukihiro

2014-07-01

The relationship between the miscibility of formulation ingredients and their crystallization during the freezing segment of the lyophilization process was studied. The thermal properties of frozen solutions containing myo-inositol and cosolutes were obtained by performing heating scans from -70 °C before and after heat treatment at -20 °C to -5 °C. Addition of dextran 40,000 reduced and prevented crystallization of myo-inositol. In the first scan, some frozen solutions containing an inositol-rich mixture with dextran showed single broad transitions (Tg's: transition temperatures of maximally freeze-concentrated solutes) that indicated incomplete mixing of the concentrated amorphous solutes. Heat treatment of these frozen solutions induced separation of the solutes into inositol-dominant and solute mixture phases (Tg' splitting) following crystallization of myo-inositol (Tg' shifting). The crystal growth involved myo-inositol molecules in the solute mixture phase. The amorphous-amorphous phase separation and resulting loss of the heteromolecular interaction in the freeze-concentrated inositol-dominant phase should allow ordered assembly of the solute molecules required for nucleation. Some dextran-rich and intermediate concentration ratio frozen solutions retained single Tg's of the amorphous solute mixture, both before and after heat treatments. The relevance of solute miscibility on the crystallization of myo-inositol was also indicated in the systems containing glucose or recombinant human albumin. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

Subsurface Characterization and Seismic Monitoring for the Southwest Partnerships Phase III Demonstration Project at Farnsworth Field, TX

NASA Astrophysics Data System (ADS)

Will, R. A.; Balch, R. S.

2015-12-01

The Southwest Partnership on Carbon Sequestration is performing seismic based characterization and monitoring activities at an active CO2 EOR project at Farnsworth Field, Texas. CO2 is anthropogenically sourced from a fertilizer and an ethanol plant. The field has 13 CO2 injectors and has sequestered 302,982 metric tonnes of CO2 since October 2013. The field site provides an excellent laboratory for testing a range of monitoring technologies in an operating CO2 flood since planned development is sequential and allows for multiple opportunities to record zero CO2 baseline data, mid-flood data, and fully flooded data. The project is comparing and contrasting several scales of seismic technologies in order to determine best practices for large scale commercial sequestration projects. Characterization efforts include an 85 km2 3D surface seismic survey, baseline and repeat 3D VSP surveys centered on injection wells, cross-well tomography baseline and repeat surveys between injector/producer pairs, and a borehole passive seismic array to monitor induced seismicity. All surveys have contributed to detailed geologic models which were then used for fluid flow and risk assessment simulations. 3D VSP and cross-well data with repeat surveys have allowed for direct comparisons of the reservoir prior to CO2 injection and at eight months into injection, with a goal of imaging the CO2 plume as it moves away from injection wells. Additional repeat surveys at regular intervals will continue to refine the plume. The goal of this work is to demonstrate seismic based technologies to monitor CO2 sequestration projects, and to contribute to best practices manuals for commercial scale CO2 sequestration projects. In this talk the seismic plan will be outlined, progress towards goals enumerated, and preliminary results from baseline and repeat seismic data will be discussed. Funding for this project is provided by the U.S. Department of Energy under Award No. DE-FC26-05NT42591.

Low temperature synthesis of Ru-Cu alloy nanoparticles with the compositions in the miscibility gap

NASA Astrophysics Data System (ADS)

Martynova, S. A.; Filatov, E. Yu.; Korenev, S. V.; Kuratieva, N. V.; Sheludyakova, L. A.; Plusnin, P. E.; Shubin, Yu. V.; Slavinskaya, E. M.; Boronin, A. I.

2014-04-01

A complex salt [Ru(NH3)5Cl][Cu(C2O4)2H2O]-the precursor of nanoalloys combining ruthenium and copper was prepared. It crystallizes in the monoclinic space group P21/n. Thermal properties of the prepared salt were examined in different atmospheres (helium, hydrogen, oxygen). Thermal decomposition of the precursor in inert atmosphere was thoroughly examined and the intermediate products were characterized. Experimental conditions for preparation of copper-rich (up to 12 at% of copper) metastable solid solution CuxRu1-x (based on Ru structure) were optimized, what is in sharp contrast to the bimetallic miscibility gap known for the bulk counterparts in a wide composition range. Catalytic properties of copper-ruthenium oxide composite were tested in catalytic oxidation of CO.

Liquid Phase Miscibility Gap Materials

NASA Technical Reports Server (NTRS)

Gelles, S. H.; Markworth, A. J.

1985-01-01

The manner in which the microstructural features of liquid-phase miscibility gap alloys develop was determined. This will allow control of the microstructures and the resultant properties of these alloys. The long-duration low gravity afforded by the shuttle will allow experiments supporting this research to be conducted with minimal interference from buoyancy effects and gravitationally driven convection currents. Ground base studies were conducted on Al-In, Cu-Pb, and Te-Tl alloys to determine the effect of cooling rate, composition, and interfacial energies on the phase separation and solidification processes that influence the development of microstructure in these alloys. Isothermal and directional cooling experiments and simulations are conducted. The ground based activities are used as a technological base from which flight experiments formulated and to which these flight experiments are compared.

Interface instabilities during displacements of two miscible fluids in a vertical pipe

NASA Astrophysics Data System (ADS)

Scoffoni, J.; Lajeunesse, E.; Homsy, G. M.

2001-03-01

We study experimentally the downward vertical displacement of one miscible fluid by another in a vertical pipe at sufficiently high velocities for diffusive effects to be negligible. For certain viscosity ratios and flow rates, the interface between the two fluids can destabilize. We determine the dimensionless flow rate Uc above which the instability is triggered and its dependence on the viscous ratio M, resulting in a stability map Uc=Uc(M). Two different instability modes have been observed: an asymmetric "corkscrew" mode and an axisymmetric one. We remark that the latter is always eventually disturbed by "corkscrew" type instabilities. We speculate that these instabilities are driven by the viscosity stratification and are analogous to those already observed in core annular flows of immiscible fluids.

Investigations on transparent liquid-miscibility gap systems

NASA Technical Reports Server (NTRS)

Lacy, L. L.; Nishioka, G.; Ross, S.

1979-01-01

Sedimentation and phase separation is a well known occurrence in monotectic or miscibility gap alloys. Previous investigations indicate that it may be possible to prepare such alloys in a low-gravity space environment but recent experiments indicate that there may be nongravity dependent phase separation processes which can hinder the formation of such alloys. Such phase separation processes are studied using transparent liquid systems and holography. By reconstructing holograms into a commercial-particle-analysis system, real time computer analysis can be performed on emulsions with diameters in the range of 5 micrometers or greater. Thus dynamic effects associated with particle migration and coalescence can be studied. Characterization studies on two selected immiscible systems including an accurate determination of phase diagrams, surface and interfacial tension measurements, surface excess and wetting behavior near critical solution temperatures completed.

Geochemical and hydrological characterization of shallow aquifer water following a nearby deep CO2 injection in Wellington, Kansas

NASA Astrophysics Data System (ADS)

Datta, S.; Andree, I.; Johannesson, K. H.; Kempton, P. D.; Barker, R.; Birdie, T. R.; Watney, W. L.

2017-12-01

Salinization or CO2 leakage from local Enhanced Oil Recovery (EOR) projects has become a possible source for contamination and water quality degradation for local irrigation or potable well users in Wellington, Kansas. Shallow domestic and monitoring wells, as well as surface water samples collected from the site, were analyzed for a wide array of geochemical proxies including major and trace ions, rare earth elements (REE), stable isotopes, dissolved organic carbon and dissolved hydrocarbons; these analytes were employed as geotracers to understand the extent of hydrologic continuity throughout the Paleozoic stratigraphic section. Previous research by Barker et al. (2012) laid the foundation through a mineralogical and geochemical investigation of the Arbuckle injection zone and assessment of overlying caprock integrity, which led to the conclusion that the 4,910-5,050' interval will safely sequester CO2 with high confidence of a low leakage potential. EOR operations using CO2 as the injectant into the Mississippian 3,677-3,706' interval was initiated in Jan 2016. Two groundwater sampling events were conducted to investigate any temporal changes in the surface and subsurface waters. Dissolved (Ca+Mg)/Na and Na/Cl mass ratio values of two domestic wells and one monitoring well ranged from 0.67 to 2.01 and 0.19 to 0.39, respectively, whereas a nearby Mississippian oil well had values of 0.20 and 0.62, respectively . δ18O and δ2H ranged from -4.74 to -5.41 ‰VSMOW and -31.4 to -34.3 ‰VSMOW, respectively, among the domestic wells and shallowest monitoring well. Conservative ion relationships in drill-stem-test waters from Arbuckle and Mississippian injection zones displayed significant variability, indicating limited vertical hydrologic communication. Total aquifer connectivity is inconclusive based on the provided data; however, a paleoterrace and incised valley within the study site are thought to be connected through a Mississippian salt plume migration passing through the major domestic wells and a well at 200 ft depth. REE patterns of the shallow monitoring wells indicate a different water source than the domestic wells in the study area.

Conflagration Analysis System II: Bibliography.

DTIC Science & Technology

1985-04-01

Therefore, it is Lmportant to examine both the reinforcement and the supplemental considerations Eor the quantitative methods for conflagration...and the meaningful quantitative factors for conflagration analysis are determined, the relevatn literature will be brought into the nainstream of the... quantitative :hods. Fire Development in Multiple Structures From a purely analytical view, the research identified in the literature fire development in

A Directory of Human Performance Models for System Design (Defence Research Group Panel 8 on the Defence Applications of Human and Bio-Medical Sciences)

DTIC Science & Technology

1992-12-27

quantities, but they are not continuously dependent on these quantities. This pure open-loop programmed-control-like behaviour is called precognitive . Like...and largely accomplished by the precognitive action and then may be completed with compeisatory eor-reducuon operations. 304. A quasilinear or

75 FR 78986 - East Cheyenne Gas Storage, LLC; Notice of Intent To Prepare an Environmental Assessment for the...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-17

..., East Cheyenne planned to do enhanced oil recovery (EOR) of petroleum reserves remaining in the storage... primarily involves redeveloping a number of existing oil production wells in the West Peetz and Lewis Creek... of construction and operation of a natural gas storage facility in two nearly depleted oil production...

Role of medium heterogeneity and viscosity contrast in miscible flow regimes and mixing zone growth: A computational pore-scale approach

NASA Astrophysics Data System (ADS)

Afshari, Saied; Hejazi, S. Hossein; Kantzas, Apostolos

2018-05-01

Miscible displacement of fluids in porous media is often characterized by the scaling of the mixing zone length with displacement time. Depending on the viscosity contrast of fluids, the scaling law varies between the square root relationship, a sign for dispersive transport regime during stable displacement, and the linear relationship, which represents the viscous fingering regime during an unstable displacement. The presence of heterogeneities in a porous medium significantly affects the scaling behavior of the mixing length as it interacts with the viscosity contrast to control the mixing of fluids in the pore space. In this study, the dynamics of the flow and transport during both unit and adverse viscosity ratio miscible displacements are investigated in heterogeneous packings of circular grains using pore-scale numerical simulations. The pore-scale heterogeneity level is characterized by the variations of the grain diameter and velocity field. The growth of mixing length is employed to identify the nature of the miscible transport regime at different viscosity ratios and heterogeneity levels. It is shown that as the viscosity ratio increases to higher adverse values, the scaling law of mixing length gradually shifts from dispersive to fingering nature up to a certain viscosity ratio and remains almost the same afterwards. In heterogeneous media, the mixing length scaling law is observed to be generally governed by the variations of the velocity field rather than the grain size. Furthermore, the normalization of mixing length temporal plots with respect to the governing parameters of viscosity ratio, heterogeneity, medium length, and medium aspect ratio is performed. The results indicate that mixing length scales exponentially with log-viscosity ratio and grain size standard deviation while the impact of aspect ratio is insignificant. For stable flows, mixing length scales with the square root of medium length, whereas it changes linearly with length during unstable flows. This scaling procedure allows us to describe the temporal variation of mixing length using a generalized curve for various combinations of the flow conditions and porous medium properties.

Phase separation of comb polymer nanocomposite melts.

PubMed

Xu, Qinzhi; Feng, Yancong; Chen, Lan

2016-02-07

In this work, the spinodal phase demixing of branched comb polymer nanocomposite (PNC) melts is systematically investigated using the polymer reference interaction site model (PRISM) theory. To verify the reliability of the present method in characterizing the phase behavior of comb PNCs, the intermolecular correlation functions of the system for nonzero particle volume fractions are compared with our molecular dynamics simulation data. After verifying the model and discussing the structure of the comb PNCs in the dilute nanoparticle limit, the interference among the side chain number, side chain length, nanoparticle-monomer size ratio and attractive interactions between the comb polymer and nanoparticles in spinodal demixing curves is analyzed and discussed in detail. The results predict two kinds of distinct phase separation behaviors. One is called classic fluid phase boundary, which is mediated by the entropic depletion attraction and contact aggregation of nanoparticles at relatively low nanoparticle-monomer attraction strength. The second demixing transition occurs at relatively high attraction strength and involves the formation of an equilibrium physical network phase with local bridging of nanoparticles. The phase boundaries are found to be sensitive to the side chain number, side chain length, nanoparticle-monomer size ratio and attractive interactions. As the side chain length is fixed, the side chain number has a large effect on the phase behavior of comb PNCs; with increasing side chain number, the miscibility window first widens and then shrinks. When the side chain number is lower than a threshold value, the phase boundaries undergo a process from enlarging the miscibility window to narrowing as side chain length increases. Once the side chain number overtakes this threshold value, the phase boundary shifts towards less miscibility. With increasing nanoparticle-monomer size ratio, a crossover of particle size occurs, above which the phase separation is consistent with that of chain PNCs. The miscibility window for this condition gradually narrows while the other parameters of the PNCs system are held constant. These results indicate that the present PRISM theory can give molecular-level details of the underlying mechanisms of the comb PNCs. It is hoped that the results can be used to provide useful guidance for the future design control of novel, thermodynamically stable comb PNCs.

Miscibility, chain packing, and hydration of 1-palmitoyl-2-oleoyl phosphatidylcholine and other lipids in surface phases.

PubMed

Smaby, J M; Brockman, H L

1985-11-01

The miscibility of 1-palmitoyl-2-oleoyl phosphatidylcholine with triolein, 1,2-diolein, 1,3-diolein, 1(3)-monoolein, oleyl alcohol, methyl oleate, oleic acid, and oleyl cyanide (18:1 lipids) was studied at the argon-water interface. The isothermal phase diagrams for the mixtures at 24 degrees were characterized by two compositional regions. At the limit of miscibility with lower mol fractions of 18:1 lipid, the surface pressure was composition-independent, but above a mixture-specific stoichiometry, surface pressure at the limit of miscibility was composition-dependent. From the two-dimensional phase rule, it was determined that at low mol fractions of 18:1 lipids, the surface consisted of phospholipid and a preferred packing array or complex of phospholipid and 18:1 lipid, whereas, above the stoichiometry of the complex, the surface phase consisted of complex and excess 18:1 lipids. In both regions of the phase diagram, mixing along the phase boundary was apparently ideal allowing application of an equation of state described earlier (J. M. Smaby and H. L. Brockman, 1984, Biochemistry, 23:3312-3316). From such analysis, apparent partial molecular areas and hydrations for phospholipid, complex, and 18:1 lipid were obtained. Comparison of these calculated parameters for the complexed and uncomplexed states shows that the aliphatic moieties behave independently of polar head group. The transition of each 18:1 chain to the complexed state involves the loss of about one interfacial water molecule and its corresponding area. For 18:1 lipids with more than one chain another two water molecules per additional chain are present in both states but contribute little to molecular area. In contrast to 18:1 lipids, the phospholipid area and hydration change little upon complexation. The uniformity of chain packing and hydration behavior among 18:1 lipid species contrasts with complex stoichiometries that vary from 0.04 to 0.65. This suggests that the stoichiometry of the preferred packing array is determined by interactions involving the more polar moieties of the 18:1 lipids and the phospholipid.

Theoretical and experimental investigation of drug-polymer interaction and miscibility and its impact on drug supersaturation in aqueous medium.

PubMed

Baghel, Shrawan; Cathcart, Helen; O'Reilly, Niall J

2016-10-01

Amorphous solid dispersions (ASDs) have the potential to offer higher apparent solubility and bioavailability of BCS class II drugs. Knowledge of the solid state drug-polymer solubility/miscibility and their mutual interaction are fundamental requirements for the effective design and development of such systems. To this end, we have carried out a comprehensive investigation of various ASD systems of dipyridamole and cinnarizine in polyvinylpyrrolidone (PVP) and polyacrylic acid (PAA) at different drug loadings. Theoretical and experimental examinations (by implementing binary and ternary Flory-Huggins (F-H) theory) related to drug-polymer interaction/miscibility including solubility parameter approach, melting point depression method, phase diagram, drug-polymer interaction in the presence of moisture and the effect of drug loading on interaction parameter were performed. The information obtained from this study was used to predict the stability of ASDs at different drug loadings and under different thermal and moisture conditions. Thermal and moisture sorption analysis not only provided the composition-dependent interaction parameter but also predicted the composition dependent miscibility. DPM-PVP, DPM-PAA and CNZ-PAA systems have shown molecular level mixing over the complete range of drug loading. For CNZ-PVP, the presence of a single Tg at lower drug loadings (10, 20 and 35%w/w) indicates the formation of solid solution. However, drug recrystallization was observed for samples with higher drug weight fractions (50 and 65%w/w). Finally, the role of polymer in maintaining drug supersaturation has also been explored. It has been found that drug-polymer combinations capable of hydrogen-bonding in the solution state (DPM-PVP, DPM-PAA and CNZ-PAA) are more effective in preventing drug crystallization compared to the drug-polymer systems without such interaction (CNZ-PVP). The DPM-PAA system outperformed all other ASDs in various stability conditions (dry-state, in the presence of moisture and in solution state), which was attributed to the drug's low crystallization tendency, the strong DPM-PAA interaction, the robustness of this interaction against moisture or water and the ability of PAA in maintaining DPM supersaturation. Copyright © 2016 Elsevier B.V. All rights reserved.

A Novel Equation-of-State to Model Microemulsion Phase Behavior for Enhanced Oil Recovery Application

NASA Astrophysics Data System (ADS)

Ghosh, Soumyadeep

Surfactant-polymer (SP) floods have significant potential to recover waterflood residual oil in shallow oil reservoirs. A thorough understanding of surfactant-oil-brine phase behavior is critical to the design of chemical EOR floods. While considerable progress has been made in developing surfactants and polymers that increase the potential of a chemical enhanced oil recovery (EOR) project, very little progress has been made to predict phase behavior as a function of formulation variables such as pressure, temperature, and oil equivalent alkane carbon number (EACN). The empirical Hand's plot is still used today to model the microemulsion phase behavior with little predictive capability as these and other formulation variables change. Such models could lead to incorrect recovery predictions and improper flood designs. Reservoir crudes also contain acidic components (primarily naphthenic acids), which undergo neutralization to form soaps in the presence of alkali. The generated soaps perform synergistically with injected synthetic surfactants to mobilize waterflood residual oil in what is termed alkali-surfactant-polymer (ASP) flooding. The addition of alkali, however, complicates the measurement and prediction of the microemulsion phase behavior that forms with acidic crudes. In this dissertation, we account for pressure changes in the hydrophilic-lipophilic difference (HLD) equation. This new HLD equation is coupled with the net-average curvature (NAC) model to predict phase volumes, solubilization ratios, and microemulsion phase transitions (Winsor II-, III, and II+). This dissertation presents the first modified HLD-NAC model to predict microemulsion phase behavior for live crudes, including optimal solubilization ratio and the salinity width of the three-phase Winsor III region at different temperatures and pressures. This new equation-of-state-like model could significantly aid the design and forecast of chemical floods where key variables change dynamically, and in screening of potential candidate reservoirs for chemical EOR. The modified HLD-NAC model is also extended here for ASP flooding. We use an empirical equation to calculate the acid distribution coefficient from the molecular structure of the soap. Key HLD-NAC parameters like optimum salinities and optimum solubilization ratios are calculated from soap mole fraction weighted equations. The model is tuned to data from phase behavior experiments with real crudes to demonstrate the procedure. We also examine the ability of the new model to predict fish plots and activity charts that show the evolution of the three-phase region. The modified HLD-NAC equations are then made dimensionless to develop important microemulsion phase behavior relationships and for use in tuning the new model to measured data. Key dimensionless groups that govern phase behavior and their effects are identified and analyzed. A new correlation was developed to predict optimum solubilization ratios at different temperatures, pressures and oil EACN with an average relative error of 10.55%. The prediction of optimum salinities with the modified HLD approach resulted in average relative errors of 2.35%. We also present a robust method to precisely determine optimum salinities and optimum solubilization ratios from salinity scan data with average relative errors of 1.17% and 2.44% for the published data examined.

Notes: Water Flow and Chemical Retardation in Soils: A Simple Effective Laboratory Demonstration.

ERIC Educational Resources Information Center

Bowman, R. S.; And Others

1988-01-01

Describes a laboratory demonstration that illustrates principles of miscible displacement and chemical retardation in soils. Discusses how the experimental apparatus can be constructed from readily available materials. (TW)

Contribution to the thermodynamic description of the corium - The U-Zr-O system

NASA Astrophysics Data System (ADS)

Quaini, A.; Guéneau, C.; Gossé, S.; Dupin, N.; Sundman, B.; Brackx, E.; Domenger, R.; Kurata, M.; Hodaj, F.

2018-04-01

In order to understand the stratification process that may occur in the late phase of the fuel degradation during a severe accident in a PWR, the thermodynamic knowledge of the U-Zr-O system is crucial. The presence of a miscibility gap in the U-Zr-O liquid phase may lead to a stratified configuration, which will impact the accidental scenario management. The aim of this work was to obtain new experimental data in the U-Zr-O liquid miscibility gap. New tie-line data were provided at 2567 ± 25 K. The related thermodynamic models were reassessed using present data and literature values. The reassessed model will be implemented in the TAF-ID international database. The composition and density of phases potentially formed during stratification will be predicted by coupling current thermodynamic model with thermal-hydraulics codes.

Effect of solvent evaporation and coagulation on morphology development of asymmetric membranes

NASA Astrophysics Data System (ADS)

Chandrasekaran, Neelakandan; Kyu, Thein

2008-03-01

Miscibility behavior of blends of amorphous polyamide (PA) and polyvinylpyrrolidone (PVP) was studied in relation to membrane formation. Dimethylsulfoxide (DMSO) and water were used as solvent and non-solvent, respectively. Differential scanning calorimetry and cloud point measurements revealed that the binary PA/PVP blends as well as the ternary PA/PVP/DMSO system were completely miscible at all compositions. However, the addition of non-solvent (water) to this ternary system has led to phase separation. Visual turbidity study was used to establish a ternary liquid-liquid phase diagram of the PA-PVP/DMSO/water system. Scanning Electron Microscopy (SEM) showed the development of finger-like and sponge-like cross sectional morphologies during coagulation. Effects of polymer concentration, PA/PVP blend ratio, solvent/non-solvent quality, and evaporation time on the resulting membrane morphology will be discussed.

How the flow affects the phase behaviour and microstructure of polymer nanocomposites.

PubMed

Stephanou, Pavlos S

2015-02-14

We address the issue of flow effects on the phase behaviour of polymer nanocomposite melts by making use of a recently reported Hamiltonian set of evolution equations developed on principles of non-equilibrium thermodynamics. To this end, we calculate the spinodal curve, by computing values for the nanoparticle radius as a function of the polymer radius-of-gyration for which the second derivative of the generalized free energy of the system becomes zero. Under equilibrium conditions, we recover the phase diagram predicted by Mackay et al. [Science 311, 1740 (2006)]. Under non-equilibrium conditions, we account for the extra terms in the free energy due to changes in the conformations of polymer chains by the shear flow. Overall, our model predicts that flow enhances miscibility, since the corresponding miscibility window opens up for non-zero shear rate values.

Brewster Angle Microscopy Study of Model Stratum Corneum Lipid Monolayers at the Air-Water Interface

NASA Astrophysics Data System (ADS)

Adams, Ellen; Champagne, Alex; William, Joseph; Allen, Heather

2012-04-01

As the first and last barrier in the body, the stratum corneum (SC) is essential to life. Understanding the interactions and organization of lipids within the SC provides insight into essential physiological processes, including water loss prevention and the adsorption of substances from the environment. Langmuir monolayers have long been used to study complex systems, such as biological membranes and marine aerosols, due to their ability to shed light on intermolecular interactions. In this study, lipid mixtures with varying cholesterol and cerebroside ratios were investigated at the air/water interface. Surface tension measurements along with Brewster angle microscopy (BAM) images were used to examine the lipid phase transitions. Results indicate that cholesterol and cerebrosides form miscible monolayers, exhibiting ideal behavior. BAM images of a singular, uniform collapse phase also suggest formation of a miscible monolayer.

Crystallization of D-mannitol in binary mixtures with NaCl: phase diagram and polymorphism.

PubMed

Telang, Chitra; Suryanarayanan, Raj; Yu, Lian

2003-12-01

To study the crystallization, polymorphism, and phase behavior of D-mannitol in binary mixtures with NaCl to better understand their interactions in frozen aqueous solutions. Differential scanning calorimetry, hot-stage microscopy, Raman microscopy, and variable-temperature X-ray diffractometry were used to characterize D-mannitol-NaCl mixtures. NaCl and D-mannitol exhibited significant melt miscibility (up to 7.5% w/w or 0.20 mole fraction of NaCl) and a eutectic phase diagram (eutectic composition 7.5% w/w NaCl; eutectic temperature 150 degrees C for the alpha and beta polymorphs of D-mannitol and 139 degrees C for the delta). The presence of NaCl did not prevent mannitol from crystallizing but, depending on sample size, affected the polymorph crystallized: below 10 mg, delta was obtained; above 100 mg, alpha was obtained. Pure mannitol crystallized under the same conditions first as the delta polymorph and then as the a polymorph, with the latter nucleating on the former. KCl showed similar eutectic points and melt miscibility with D-mannitol as NaCl. LiCl yielded lower eutectic melting points, inhibited the crystallization of D-mannitol during cooling, and enabled the observation of its glass transition. Despite their structural dissimilarity, significant melt miscibility exists between D-mannitol and NaCl. Their phase diagram has been determined and features polymorph-dependent eutectic points. NaCl influences the polymorphic behavior of mannitol, and the effect is linked to the crystallization of mannitol in two polymorphic stages.

CFD study of mixing miscible liquid with high viscosity difference in a stirred tank

NASA Astrophysics Data System (ADS)

Madhania, S.; Cahyani, A. B.; Nurtono, T.; Muharam, Y.; Winardi, S.; Purwanto, W. W.

2018-03-01

The mixing process of miscible liquids with high viscosity difference is crucial role even though the solution mutually dissolved. This paper describes the mixing behaviour of the water-molasses system in a conical-bottomed cylindrical stirred tank (D = 0.28 m and H = 0.395 m) equipped with a side-entry Marine propeller (d = 0.036 m) under the turbulence regime using a three-dimensional and transient CFD-simulation. The objective of this work is to compare the solution strategies was applied in the computational analysis to capture the detail phenomena of mixing two miscible liquid with high viscosity difference. Four solution strategies that have been used are the RANS Standards k-ε (SKE) model as the turbulence model coupled with the Multiple Reference Frame (MRF) method for impeller motion, the RANS Realizable k-ε (RKE) combine with the MRF, the Large Eddy Simulation (LES) coupled with the Sliding Mesh (SM) method and the LES-MRF combination. The transient calculations were conducted with Ansys Fluent 17.1 version. The mixing behaviour and the propeller characteristic are to be compared and discussed in this work. The simulation results show the differences of flow pattern and the molasses distribution profile for every solution strategy. The variation of the flow pattern which happened in each solution strategy showing an instability of the mixing process in stirred tank. The LES-SM strategy shows the realistic direction of flow than another solution strategies.

Amorphous and Crystalline Particulates: Challenges and Perspectives in Drug Delivery.

PubMed

Al-Obaidi, Hisham; Majumder, Mridul; Bari, Fiza

2017-01-01

Crystalline and amorphous dispersions have been the focus of academic and industrial research due to their potential role in formulating poorly water-soluble drugs. This review looks at the progress made starting with crystalline carriers in the form of eutectics moving towards more complex crystalline mixtures. It also covers using glassy polymers to maintain the drug as amorphous exhibiting higher energy and entropy. However, the amorphous form tends to recrystallize on storage, which limits the benefits of this approach. Specific interactions between the drug and the polymer may retard this spontaneous conversion of the amorphous drug. Some studies have shown that it is possible to maintain the drug in the amorphous form for extended periods of time. For the drug and the polymer to form a stable mixture they have to be miscible on a molecular basis. Another form of solid dispersions is pharmaceutical co-crystals, for which research has focused on understanding the chemistry, crystal engineering and physico-chemical properties. USFDA has issued a guidance in April 2013 suggesting that the co-crystals as a pharmaceutical product may be a reality; but just not yet! While some of the research is still oriented towards application of these carriers, understanding the mechanism by which drug-carrier miscibility occurs is also covered. Within this context is the use of thermodynamic models such as Flory-Huggins model with some examples of studies used to predict miscibility. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Time-of-flight expansion of binary Bose–Einstein condensates at finite temperature

NASA Astrophysics Data System (ADS)

Lee, K. L.; Jørgensen, N. B.; Wacker, L. J.; Skou, M. G.; Skalmstang, K. T.; Arlt, J. J.; Proukakis, N. P.

2018-05-01

Ultracold quantum gases provide a unique setting for studying and understanding the properties of interacting quantum systems. Here, we investigate a multi-component system of 87Rb–39K Bose–Einstein condensates (BECs) with tunable interactions both theoretically and experimentally. Such multi-component systems can be characterized by their miscibility, where miscible components lead to a mixed ground state and immiscible components form a phase-separated state. Here we perform the first full simulation of the dynamical expansion of this system including both BECs and thermal clouds, which allows for a detailed comparison with experimental results. In particular we show that striking features emerge in time-of-flight (TOF) for BECs with strong interspecies repulsion, even for systems which were separated in situ by a large gravitational sag. An analysis of the centre of mass positions of the BECs after expansion yields qualitative agreement with the homogeneous criterion for phase-separation, but reveals no clear transition point between the mixed and the separated phases. Instead one can identify a transition region, for which the presence of a gravitational sag is found to be advantageous. Moreover, we analyse the situation where only one component is condensed and show that the density distribution of the thermal component also shows some distinct features. Our work sheds new light on the analysis of multi-component systems after TOF and will guide future experiments on the detection of miscibility in these systems.

Calcium Ions as “Miscibility Switch”: Colocalization of Surfactant Protein B with Anionic Lipids under Absolute Calcium Free Conditions

PubMed Central

Saleem, Mohammed; Meyer, Michaela C.; Breitenstein, Daniel; Galla, Hans-Joachim

2009-01-01

Abstract One of the main determinants of lung surfactant function is the complex interplay between its protein and lipid components. The lipid specificity of surfactant protein B (SP-B), however, and the protein's ability to selectively squeeze out lipids, has remained contradictory. In this work we present, for the first time to our knowledge, by means of time-of-flight secondary ion mass spectrometry chemical imaging, a direct evidence for colocalization of SP-B as well as its model peptide KL4 with negatively charged dipalmitoylphosphatidylglycerol under absolute calcium free conditions. Our results prove that protein/lipid localization depends on the miscibility of all surfactant components, which itself is influenced by subphase ionic conditions. In contrast to our earlier studies reporting SP-B/KL4 colocalization with zwitterionic dipalmitoylphosphatidylcholine, in the presence of even the smallest traces of calcium, we finally evidence an apparent reversal of protein/lipid mixing behavior upon calcium removal with ethylene diamine tetraacetic acid. In addition, scanning force microscopy measurements reveal that by depleting the subphase from calcium ions the protrusion formation ability of SP-B or KL4 is not hampered. However, in the case of KL4, distinct differences in protrusion morphology and height are visible. Our results support the idea that calcium ions act as a “miscibility switch” in surfactant model systems and probably are one of the major factors steering lipid/protein mixing behavior as well as influencing the protein's protrusion formation ability. PMID:19619464

Differential retention and release of CO 2 and CH 4 in kerogen nanopores: Implications for gas extraction and carbon sequestration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ho, Tuan Anh; Wang, Yifeng; Xiong, Yongliang

Methane (CH 4) and carbon dioxide (CO 2), the two major components generated from kerogen maturation, are stored dominantly in nanometer-sized pores in shale matrix as (1) a compressed gas, (2) an adsorbed surface species and/or (3) a species dissolved in pore water (H 2O). In addition, supercritical CO 2 has been proposed as a fracturing fluid for simultaneous enhanced oil/gas recovery (EOR) and carbon sequestration. A mechanistic understanding of CH 4-CO 2-H 2O interactions in shale nanopores is critical for designing effective operational processes. Using molecular simulations, we show that kerogen preferentially retains CO 2 over CH 4 andmore » that the majority of CO 2 either generated during kerogen maturation or injected in EOR will remain trapped in the kerogen matrix. The trapped CO 2 may be released only if the reservoir pressure drops below the supercritical CO 2 pressure. When water is present in the kerogen matrix, it may block CH 4 release. Furthermore, the addition of CO 2 may enhance CH 4 release because CO 2 can diffuse through water and exchange for adsorbed methane in the kerogen nanopores.« less

Evaluation of alcohol dehydrogenase and aldehyde dehydrogenase enzymes as bi-enzymatic anodes in a membraneless ethanol microfluidic fuel cell

NASA Astrophysics Data System (ADS)

Galindo-de-la-Rosa, J.; Arjona, N.; Arriaga, L. G.; Ledesma-García, J.; Guerra-Balcázar, M.

2015-12-01

Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (AldH) enzymes were immobilized by covalent binding and used as the anode in a bi-enzymatic membraneless ethanol hybrid microfluidic fuel cell. The purpose of using both enzymes was to optimize the ethanol electro-oxidation reaction (EOR) by using ADH toward its direct oxidation and AldH for the oxidation of aldehydes as by-products of the EOR. For this reason, three enzymatic bioanode configurations were evaluated according with the location of enzymes: combined, vertical and horizontally separated. In the combined configuration, a current density of 16.3 mA cm-2, a voltage of 1.14 V and a power density of 7.02 mW cm-2 were obtained. When enzymes were separately placed in a horizontal and vertical position the ocp drops to 0.94 V and to 0.68 V, respectively. The current density also falls to values of 13.63 and 5.05 mA cm-2. The decrease of cell performance of bioanodes with separated enzymes compared with the combined bioanode was of 31.7% and 86.87% for the horizontal and the vertical array.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jacobs, Daniel C.; Bowman, Judd; Aguirre, James E., E-mail: daniel.c.jacobs@asu.edu

As observations of the Epoch of Reionization (EoR) in redshifted 21 cm emission begin, we assess the accuracy of the early catalog results from the Precision Array for Probing the Epoch of Reionization (PAPER) and the Murchison Wide-field Array (MWA). The MWA EoR approach derives much of its sensitivity from subtracting foregrounds to <1% precision, while the PAPER approach relies on the stability and symmetry of the primary beam. Both require an accurate flux calibration to set the amplitude of the measured power spectrum. The two instruments are very similar in resolution, sensitivity, sky coverage, and spectral range and havemore » produced catalogs from nearly contemporaneous data. We use a Bayesian Markov Chain Monte Carlo fitting method to estimate that the two instruments are on the same flux scale to within 20% and find that the images are mostly in good agreement. We then investigate the source of the errors by comparing two overlapping MWA facets where we find that the differences are primarily related to an inaccurate model of the primary beam but also correlated errors in bright sources due to CLEAN. We conclude with suggestions for mitigating and better characterizing these effects.« less

Polarized Power Spectra from HERA-19 Commissioning Data: Effect of Calibration Techniques

NASA Astrophysics Data System (ADS)

Chichura, Paul; Igarashi, Amy; Fox Fortino, Austin; Kohn, Saul; Aguirre, James; HERA Collaboration

2018-01-01

Studying the Epoch of Reionization (EOR) is crucial for cosmologists as it not only provides information about the first generation of stars and galaxies, but it may also help answer any number of fundamental astrophysical questions. The Hydrogen Epoch of Reionization Array (HERA) is doing this by examining emission from the 21cm hyperfine transition of neutral hydrogen, which has been identified as a promising probe of reionization. Currently, HERA is still in its commissioning phase; 37 of the planned 350 dishes have been constructed and analysis has begun for data received from the first 19 dishes built. With the creation of fully polarized power spectra, we investigate how different data calibration techniques affect the power spectra and whether or not ordering these techniques in different ways affects the results. These calibration techniques include using both non-imaging redundant measurements within the array to calibrate, as well as more traditional approaches based on imaging and calibrating to a model of sky. We explore the degree to which the different calibration schemes affect leakage of foreground emission to regions of Fourier space where EoR the power spectrum is expected to be measurable.

VizieR Online Data Catalog: KGS EoR0 Catalogue (Carroll+, 2016)

NASA Astrophysics Data System (ADS)

Carroll, P. A.; Line, J.; Morales, M. F.; Barry, N.; Beardsley, A. P.; Hazelton, B. J.; Jacobs, D. C.; Pober, J. C.; Sullivan, I. S.; Webster, R. L.; Bernardi, G.; Bowman, J. D.; Briggs, F.; Cappallo, R. J.; Corey, B. E.; de Oliveira-Costa, A.; Dillon, J. S.; Emrich, D.; Ewall-Wice, A.; Feng, L.; Gaensler, B. M.; Goeke, R.; Greenhill, L. J.; Hewitt, J. N.; Hurley-Walker, N.; Johnston-Hollitt, M.; Kaplan, D. L.; Kasper, J. C.; Kim, Hs.; Kratzenberg, E.; Lenc, E.; Loeb, A.; Lonsdale, C. J.; Lynch, M. J.; McKinley, B.; McWhirter, S. R.; Mitchell, D. A.; Morgan, E.; Neben, A. R.; Oberoi, D.; Offringa, A. R.; Ord, S. M.; Paul, S.; Pindor, B.; Prabu, T.; Procopio, P.; Riding, J.; Rogers, A. E. E.; Roshi, A.; Udaya Shankar, N.; Sethi, S. K.; Srivani, K. S.; Subrahmanyan, R.; Tegmark, M.; Thyagarajan, N.; Tingay, S. J.; Trott, C. M.; Waterson, M.; Wayth, R. B.; Whitney, A. R.; Williams, A.; Williams, C. L.; Wu, C.; Wyithe, J. S. B.

2018-01-01

The MWA EoR0 field is centred at RA=0h and Dec=-27°, and was chosen because it has no bright complex sources in the primary field of view. The FWHM of the antenna beam is approximately 20°, but sources in the edges of the beam and first few side lobes are clearly visible and should be subtracted (Thyagarajan et al., 2015ApJ...804...14T, 2015ApJ...807L..28T; Pober et al., 2016ApJ...819....8P). For this catalogue we concentrate on identifying sources in the primary beam but go out to the 5 per cent power point (nearly first beam null, ~1400deg2). The data for this catalogue include 752min snapshot observations (112s consecutive integrations with 8s gaps) from the night of 2013 August 23. The observations were made at 182MHz with 31MHz bandwidth and cover 2.5h in total. This process for source finding, measurement, and classification has been termed KATALOGSS (KDD Astrometry, Trueness, and Apparent Luminosity of Galaxies in Snapshot Surveys; hereafter abbreviated to KGS). (1 data file).

Condom Effectiveness against Non-Viral Sexually Transmitted Infections: A Prospective Study Using Electronic Daily Diaries

PubMed Central

Crosby, Richard; Charnigo, Richard A.; Weathers, Chandra; Caliendo, Angela M.; Shrier, Lydia A.

2012-01-01

Objectives To prospectively evaluate the protective value of consistent and correct use of latex condoms against the acquisition of Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis. Methods Patients (N=929) attending clinics that treat sexually transmitted infections (STIs) were prospectively followed for up to six months. Urine STI nucleic acid amplification testing was performed at baseline, three months, and six months. Participants were instructed to respond to daily prompts from a hand-held device by completing a report for each penile-vaginal sexual intercourse event. Generalized estimating equation models examined associations of consistent as well as consistent and correct condom use with STI incidence over 3-month intervals. Results Consistent condom use was not significantly associated with STI incidence (Estimated Odds Ratio [EOR]=.75; 95% confidence interval [CI]=.43-1.30; P=.31). However, individuals who used condoms both correctly and consistently were estimated to have 59% lower odds of acquiring an STI (EOR = .41; 95% CI = .19-.90; P = .026), compared to those who did not. Conclusions The correct as well as the consistent use of condoms greatly reduces the odds of non-viral STI acquisition. PMID:23002192

Production of a Lipopeptide Biosurfactant by a Novel Bacillus sp. and Its Applicability to Enhanced Oil Recovery.

PubMed

Varadavenkatesan, Thivaharan; Murty, Vytla Ramachandra

2013-01-01

Biosurfactants are surface-active compounds derived from varied microbial sources including bacteria and fungi. They are secreted extracellularly and have a wide range of exciting properties for bioremediation purposes. They also have vast applications in the food and medicine industry. With an objective of isolating microorganisms for enhanced oil recovery (EOR) operations, the study involved screening of organisms from an oil-contaminated site. Morphological, biochemical, and 16S rRNA analysis of the most promising candidate revealed it to be Bacillus siamensis, which has been associated with biosurfactant production, for the first time. Initial fermentation studies using mineral salt medium supplemented with crude oil resulted in a maximum biosurfactant yield of 0.64 g/L and reduction of surface tension to 36.1 mN/m at 96 h. Characterization studies were done using thin layer chromatography and Fourier transform infrared spectroscopy. FTIR spectra indicated the presence of carbonyl groups, alkyl bonds, and C-H and N-H stretching vibrations, typical of peptides. The extracted biosurfactant was stable at extreme temperatures, pH, and salinity. Its applicability to EOR was further verified by conducting sand pack column studies that yielded up to 60% oil recovery.

Differential retention and release of CO 2 and CH 4 in kerogen nanopores: Implications for gas extraction and carbon sequestration

DOE PAGES

Ho, Tuan Anh; Wang, Yifeng; Xiong, Yongliang; ...

2018-02-06

Methane (CH 4) and carbon dioxide (CO 2), the two major components generated from kerogen maturation, are stored dominantly in nanometer-sized pores in shale matrix as (1) a compressed gas, (2) an adsorbed surface species and/or (3) a species dissolved in pore water (H 2O). In addition, supercritical CO 2 has been proposed as a fracturing fluid for simultaneous enhanced oil/gas recovery (EOR) and carbon sequestration. A mechanistic understanding of CH 4-CO 2-H 2O interactions in shale nanopores is critical for designing effective operational processes. Using molecular simulations, we show that kerogen preferentially retains CO 2 over CH 4 andmore » that the majority of CO 2 either generated during kerogen maturation or injected in EOR will remain trapped in the kerogen matrix. The trapped CO 2 may be released only if the reservoir pressure drops below the supercritical CO 2 pressure. When water is present in the kerogen matrix, it may block CH 4 release. Furthermore, the addition of CO 2 may enhance CH 4 release because CO 2 can diffuse through water and exchange for adsorbed methane in the kerogen nanopores.« less

Post waterflood CO{sub 2} miscible flood in light oil, fluvial-dominated deltaic reservoir. Annual report, fiscal year 1996

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1996-08-15

The Port Neches CO{sub 2} flood has been operating for nearly 4 years. The project performance during the past year has been adversely affected by several factors including: water blockage, low residual oil saturation and wellbore mechanical problems. The company attempted to test a new procedure in a new fault block using CO{sub 2} to accelerate primary production in order to improve the primary reserves net present value. The test was abandoned when the discovery well Polk B-39 for the Marg Area 3 was a dry hole. Also, during this period the company terminated all new CO{sub 2} purchases frommore » Cardox for economical reasons, while continuing to recycle produced CO{sub 2}. A data base for FDD reservoirs for the Louisiana and Texas Gulf Coast Region was developed by LSU and SAIC. This data base includes reservoir parameters and performance data for reservoirs with significant production and OOIP volumes that are amenable to CO{sub 2} injection. A paper discussing the Port Neches CO{sub 2} project was presented at the 1996 SPE/DOE Symposium on Improved Oil Recovery.« less

Viscosity measurements of CO2-in-water foam with dodecyl polypropoxy sulfate surfactants for enhanced oil recovery application

NASA Astrophysics Data System (ADS)

Pramudita, Ria Ayu; Ryoo, Won Sun

2016-08-01

Apparent viscosities of CO2-in-water foams were measured in a wide range of shear rate from 50 to 105 inverse second for enhanced oil recovery (EOR) application. The CO2-in-water dispersions, made of 50:50 weight proportions of CO2 and water with 1 wt.% surfactant concentration, were prepared in high-pressure recirculation apparatus under pressure where CO2 density becomes 0.7, 0.8, and 0.9 g/mL at each temperature of 35, 45, and 55°C. The surfactants used for the foam generation were sodium dodecyl polypropoxy sulfates with average propoxylation degrees of 4.7 and 6.2. The foam viscosity showed shear thinning behaviors with power-law indices ranging from 0.80 to 0.85, and approached a Newtonian regime in the lower shear rate range at several tens of inverse second. Zero-shear viscosity values projected from experimental data based on Ellis model were as high as 57.4 mPa·s and enough to control the mobility of water and CO2 in oil reservoirs.

Epoch of Reionization : An Investigation of the Semi-Analytic 21CMMC Code

NASA Astrophysics Data System (ADS)

Miller, Michelle

2018-01-01

After the Big Bang the universe was filled with neutral hydrogen that began to cool and collapse into the first structures. These first stars and galaxies began to emit radiation that eventually ionized all of the neutral hydrogen in the universe. 21CMMC is a semi-numerical code that takes simulated boxes of this ionized universe from another code called 21cmFAST. Mock measurements are taken from the simulated boxes in 21cmFAST. Those measurements are thrown into 21CMMC and help us determine three major parameters of this simulated universe: virial temperature, mean free path, and ionization efficiency. My project tests the robustness of 21CMMC on universe simulations other than 21cmFAST to see whether 21CMMC can properly reconstruct early universe parameters given a mock “measurement” in the form of power spectra. We determine that while two of the three EoR parameters (Virial Temperature and Efficiency) have some reconstructability, the mean free path parameter in the code is the least robust. This requires development of the 21CMMC code.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Porse, Sean L.; Wade, Sarah; Hovorka, Susan D.

Risk communication literature suggests that for a number of reasons, the public may perceive a risk to be greater than indicated by its statistical probability. Public concern over risk can lead to significant and costly delays in project permitting and operations. Considering these theories, media coverage of CO₂-related well blowouts in 2013 gave rise to the questions: What is the risk of CO₂ well blowouts associated with CCUS through CO₂ EOR? What is the potential public perception of those risks? What information could be used to respond to public concern? To address these questions, this study aims to: 1) providemore » a framework for understanding the nature of onshore well blowouts, 2) quantify the incidence of such events for three specific geographic regions of Texas, 3) relate this data to CCUS and findings from other studies, and 4) explore the potential implications for public perception of this risk associated with CCUS projects. While quantifying answers to these questions proved to be challenging, the results from this study suggest that (1) the perceived risk of CO₂ well blowouts may exceed the statistical risk and (2) information that could be used to address this gap could be made more readily available to the greater benefit of industry and stakeholders who support the development of CCUS as an option for addressing anthropogenic CO₂ emissions. The study also suggests approaches to best conduct such data inquiries.« less

O5.01STANDARDS AND ADVANCED TESTING FOR INTRAOPERATIVE LANGUAGE AND COGNITIVE MAPPING

PubMed Central

Comi, A.; Riva, M.; Casarotti, A.; Fava, E.; Pessina, F.; Papagno, C.; Bello, L.

2014-01-01

Resection of tumors involving language pathways requires the intraoperative identification of cortical and subcortical sites mediating the various language components, which determines the extent of resection (EOR). One of the critical point is which test(s) has to be performed during subcortical mapping. Object naming is the most used one, but it may have the limit to miss other components of language such as verb naming and generation, or comprehension of words or sentences, potentially resulting in permanent post operative deficits. Patients can be submitted intraoperatively to complex batteries of tests, resulting in limited performance and high chance of intraoperative fatigue, resulting in poor mapping. We revised our experience on subcortical language mapping in a series of patients with language pathways gliomas, in which two strategies for subcortical mapping were applied: in a first group only naming was used; in the second group, object naming was prevalently used but integrated with other tests (verb naming and generation, comprehension of words or sentences, number recognition and calculation). Results were evaluated as immediate and permanent deficits by applying a large neuropsychological testing, and as EOR (on volumetric FLAIR or post Gd T1 images). The first group was composed of 221 gliomas (168 LGGs, 53 HGGs); 130 were frontal, 21 in the insula, 58 temporal, and 12 parietal. Object naming was applied for subcortical mapping in all cases; 198 patients had immediate post operative deficits. Neuropsychological evaluation at 1 months showed complete recovery in 199 patients, a mild impairment was documented in 22 patients (12 posterior temporal tumors, 6 parietal tumors, and 4 posterior insular tumors); at 3 months evaluation, 15 patients still showed a mild impairment, mainly those whose tumors were located in the posterior temporal and parietal location. EOR was total and subtotal in 48.9% and 41.5% of cases. Fatigue was observed in 12% of patients with large volume tumors. The second group was composed of 179 gliomas (155 LGGs, 24 HGGs); 61 were frontal, 38 insular, 45 temporal and 11 parietal. Object naming was used for initial mapping and for locating main subcortical tracts (IFOF, ARC, UNC); in addition, when the initial portion of these tracts was identified, other tests were applied during subcortical mapping. 165 patients had immediate post operative deficits, only 2 patients had a mild impairment at 1 and 3 months evaluation. EOR was total and subtotal in 49.6% and 47.4% of cases. Patient fatigue was shown in 9% of patients. Object naming can be safely used during subcortical mapping for resection of tumors in frontal lobe; resection of tumors in posterior temporal, insular and parietal areas requires the use of a larger battery of tests, which did not influence the chance to reach a total or subtotal resection, nor results in a higher chance of patient fatigue.

Stabilization of a finite slice in miscible displacement in homogeneous porous media

NASA Astrophysics Data System (ADS)

Pramanik, Satyajit; Mishra, Manoranjan

2016-11-01

We numerically studied the miscible displacement of a finite slice of variable viscosity and density. The stability of the finite slice depends on different flow parameters, such as displacement velocity U, mobility ratio R , and the density contrast. Series of numerical simulations corresponding to different ordered pair (R, U) in the parameter space, and a given density contrast reveal six different instability regions. We have shown that independent of the width of the slice, there always exists a region of stable displacement, and below a critical value of the slice width, this stable region increases with decreasing slice width. Further we observe that the viscous fingering (buoyancy-induced instability) at the upper interface induces buoyancy-induced instability (viscous fingering) at the lower interface. Besides the fundamental fluid dynamics understanding, our results can be helpful to model CO2 sequestration and chromatographic separation.

Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR FT-IR) Mapping Coupled with Multivariate Curve Resolution (MCR) for Studying the Miscibility of Chlorobutyl Rubber/Polyamide-12 Blends.

PubMed

Tang, Yongjiao; Jing, Nan; Zhang, Pudun

2015-11-01

A series of chlorobutyl rubber/polyamide-12 (CIIR/PA-12) blends compatibilized by different amounts of maleic anhydride (MAH) grafted polypropylene (PP-g-MAH) were investigated by attenuated total reflection Fourier transform infrared spectroscopy (ATR FT-IR) mapping. Multivariate curve resolution (MCR) was used to process the FT-IR images. Both the spectra of pure components in the blends and their concentration distributions in a micro-region were acquired. Our results demonstrated that the blend with 15 parts per hundred rubber PP-g-MAH showed the best miscibility. An amide interphase and an imide interphase were inferred by analyzing the spectra of MCR component 3 of the blends with and without PP-g-MAH, respectively. Correspondingly, two different compatibilizing mechanisms were proposed for these blends.

Initial temperatures effect on the mixing efficiency and flow modes in T-shaped micromixer

NASA Astrophysics Data System (ADS)

Lobasov, A. S.; Shebeleva, A. A.

2017-09-01

Flow patterns and mixing of liquids with different initial temperatures in T-shaped micromixers are numerically investigated on the Reynolds number range from 1 to 250. The temperature of the one of mixing media was set equal to 20°C, while the temperature of the another mixing media was varied from 10°C to 50°C its effect on the flow structure and the mixing was studied. The dependences of the mixing efficiency and the pressure difference in this mixer on the difference in initial temperatures of miscible fluids and the Reynolds number were obtained. It was shown that the presence of a difference in initial temperatures of miscible fluids leads to a shift of flow regimes and the flow and mixing of two fluids with different initial temperatures can be considered as self-similar pattern with regard to the reduced Reynolds number.

Miscible viscous fingering involving production of gel by chemical reactions

NASA Astrophysics Data System (ADS)

Nagatsu, Yuichiro; Hoshino, Kenichi

2015-11-01

We have experimentally investigated miscible viscous fingering with chemical reactions producing gel. Here, two systems were employed. In one system, sodium polyacrylate (SPA) solution and aluminum ion (Al3 +) solution were used as the more and less viscous liquids, respectively. In another system, SPA solution and ferric ion (Fe3 +) solution were used as the more and less viscous liquids, respectively. In the case of Al3 +, displacement efficiency was smaller than that in the non-reactive case, whereas in the case of Fe3 +, the displacement efficiency was larger. We consider that the difference in change of the patterns in the two systems will be caused by the difference in the properties of the gels. Therefore, we have measured the rheological properties of the gels by means of a rheometer. We discuss relationship between the VF patterns and the rheological measurement.

Density profiles around A+B→C reaction-diffusion fronts in partially miscible systems: A general classification.

PubMed

Loodts, V; Trevelyan, P M J; Rongy, L; De Wit, A

2016-10-01

Various spatial density profiles can develop in partially miscible stratifications when a phase A dissolves with a finite solubility into a host phase containing a dissolved reactant B. We investigate theoretically the impact of an A+B→C reaction on such density profiles in the host phase and classify them in a parameter space spanned by the ratios of relative contributions to density and diffusion coefficients of the chemical species. While the density profile is either monotonically increasing or decreasing in the nonreactive case, reactions combined with differential diffusivity can create eight different types of density profiles featuring up to two extrema in density, at the reaction front or below it. We use this framework to predict various possible hydrodynamic instability scenarios inducing buoyancy-driven convection around such reaction fronts when they propagate parallel to the gravity field.

Internal density waves of shock type induced by chemoconvection in miscible reacting liquids

NASA Astrophysics Data System (ADS)

Bratsun, D. A.

2017-10-01

A theoretical explanation of the phenomenon of spontaneous emergence of density waves experimentally observed recently in bilayered systems of miscible liquids placed in a narrow vertical gap of the Hele-Shaw cell in the gravitational field is provided. Upper and lower layers represent aqueous solutions of acids and bases, respectively, whose contact leads to the beginning of a neutralization reaction. The process is accompanied by a strong dependence of the reagent's diffusion coefficients on their concentrations, giving rise to the generation of local density pockets, in which convection develops. The cavities collapse under certain conditions, causing a density jump, which moves faster than typical perturbations in a medium and takes the form of a shock wave. A mathematical model of the phenomenon is proposed, which can be formally reduced to equations of motion of a compressible gas under certain assumptions. Numerical calculations are given and compared with the experimental data.

Electro-optical properties of low viscosity driven holographic polymer dispersed liquid crystals

NASA Astrophysics Data System (ADS)

Moon, K. R.; Bae, S. Y.; Kim, B. K.

2015-04-01

Relative diffraction efficiency (RDE), operating voltage, and response times are most important performance characteristics of holographic polymer dispersed liquid crystals (HPDLC). Two types of triallyl isocyanurate (TI) having different structures were incorporated into the conventional transmission grating of HPDLC. Premix viscosity decreased by 13-18% with up to 3% TI, beyond which it increased. TI eliminated induction period and augmented initial grating formation rate at all contents. Saturation RDE increased over 200% while threshold voltage and rise time decreased to about half and 2/3, respectively up to 3% TI, beyond which the tendencies were reversed. Among the two TIs, low viscosity monomer (TA) showed high RDE, while high miscibility monomer (TE) low characteristic voltages and short response times. It is concluded that grating formation is largely favored by low viscosity, while interface tensions and electro-optical performances by miscibility at similar viscosities.

Miscibility and crystallization behavior of poly (3-hydroxybutyrate) and poly (ethylene glycol) blends studied by positron annihilation spectroscopy

NASA Astrophysics Data System (ADS)

Abdel-Hady, E. E.; Abdel-Hamed, M. O.; Hammam, A. M.

2011-01-01

Positron annihilation Lifetime (PAL) spectroscopy has been used to study the effect of PEG concentrations on the free volume properties of PHB. The data revealed that the ortho-positronium (o-Ps) lifetime τPs increases with 20% increase in concentration, decrease as the concentration increases to 40%, then rapid increase at 50% concentration of PEG. The o-Ps intensity, I3, shows a linear dependence as the concentration increases with a discontinuity at 20% concentration of PEG. Furthermore, the results presented and discussed in this work show that the PHB and PEG are miscible up to 40% of PEG but greater than 40%, the blend is immiscible. In addition, the mechanical properties of PHB are well improved by the addition of PEG with a low concentration up to 20%, while at higher concentration the blend becomes waxy.

Confinement effects on the miscibility of block copolymer blends.

PubMed

Spencer, Russell K W; Matsen, Mark W

2016-04-01

Thin films of long and short symmetric AB diblock copolymers are examined using self-consistent field theory (SCFT). We focus on hard confining walls with a preference for the A component, such that the lamellar domains orient parallel to the film with an even number ν of monolayers. For neat melts, confinement causes the lamellar period, D, to deviate from its bulk value, Db, in order to be commensurate with the film thickness, i.e., L = νD/2. For blends, however, the melt also has the option of macrophase separating into ν(l) large and ν((s)) small monolayers so as to provide a better fit, where L = ν(l)D(l)/2 + ν(s)D((s))/2. In addition to performing full SCFT calculations of the entire film, we develop a semi-analytical calculation for the coexistence of thick and thin monolayers that helps explain the complicated interplay between miscibility and commensurability.

Polymer collapse in miscible good solvents is a generic phenomenon driven by preferential adsorption

PubMed Central

Mukherji, Debashish; Marques, Carlos M.; Kremer, Kurt

2014-01-01

Water and alcohol, such as methanol or ethanol, are miscible and, individually, good solvents for poly(N-isopropylacrylamide) (PNIPAm), but this polymer precipitates in water–alcohol mixtures. The intriguing behaviour of solvent mixtures that cannot dissolve a given polymer or a given protein, while the same macromolecule dissolves well in each of the cosolvents, is called cononsolvency. It is a widespread phenomenon, relevant for many formulation steps in the physicochemical and pharmaceutical industry, that is usually explained by invoking specific chemical details of the mixtures: as such, it has so far eluded any generic explanation. Here, by using a combination of simulations and theory, we present a simple and universal treatment that requires only the preferential interaction of one of the cosolvents with the polymer. The results show striking quantitative agreement with experiments and chemically specific simulations, opening a new perspective towards an operational understanding of macromolecular solubility. PMID:25216245

Buoyant miscible displacement flow of shear-thinning fluids: Experiments and Simulations

NASA Astrophysics Data System (ADS)

Ale Etrati Khosroshahi, Seyed Ali; Frigaard, Ian

2017-11-01

We study displacement flow of two miscible fluids with density and viscosity contrast in an inclined pipe. Our focus is mainly on displacements where transverse mixing is not significant and thus a two-layer, stratified flow develops. Our experiments are carried out in a long pipe, covering a wide range of flow-rates, inclination angles and viscosity ratios. Density and viscosity contrasts are achieved by adding Glycerol and Xanthan gum to water, respectively. At each angle, flow rate and viscosity ratio are varied and density contrast is fixed. We identify and map different flow regimes, instabilities and front dynamics based on Fr , Re / Frcosβ and viscosity ratio m. The problem is also studied numerically to get a better insight into the flow structure and shear-thinning effects. Numerical simulations are completed using OpenFOAM in both pipe and channel geometries and are compared against the experiments. Schlumberger, NSERC.

Effect of critical molecular weight of PEO in epoxy/EPO blends as characterized by advanced DSC and solid-state NMR

NASA Astrophysics Data System (ADS)

Wang, Xiaoliang; Lu, Shoudong; Sun, Pingchuan; Xue, Gi

2013-03-01

The differential scanning calorimetry (DSC) and solid state NMR have been used to systematically study the length scale of the miscibility and local dynamics of the epoxy resin/poly(ethylene oxide) (ER/PEO) blends with different PEO molecular weight. By DSC, we found that the diffusion behavior of PEO with different Mw is an important factor in controlling these behaviors upon curing. We further employed two-dimensional 13C-{1H}PISEMA NMR experiment to elucidate the possible weak interaction and detailed local dynamics in ER/PEO blends. The CH2O group of PEO forms hydrogen bond with hydroxyl proton of cured-ER ether group, and its local dynamics frozen by such interaction. Our finding indicates that molecular weight (Mw) of PEO is a crucial factor in controlling the miscibility, chain dynamics and hydrogen bonding interaction in these blends.

Development of a Polarizable Force Field for Molecular Dynamics Simulations of Poly (Ethylene Oxide) in Aqueous Solution.

PubMed

Starovoytov, Oleg N; Borodin, Oleg; Bedrov, Dmitry; Smith, Grant D

2011-06-14

We have developed a quantum chemistry-based polarizable potential for poly(ethylene oxide) (PEO) in aqueous solution based on the APPLE&P polarizable ether and the SWM4-DP polarizable water models. Ether-water interactions were parametrized to reproduce the binding energy of water with 1,2-dimethoxyethane (DME) determined from high-level quantum chemistry calculations. Simulations of DME-water and PEO-water solutions at room temperature using the new polarizable potentials yielded thermodynamic properties in good agreement with experimental results. The predicted miscibility of PEO and water as a function of the temperature was found to be strongly correlated with the predicted free energy of solvation of DME. The developed nonbonded force field parameters were found to be transferrable to poly(propylene oxide) (PPO), as confirmed by capturing, at least qualitatively, the miscibility of PPO in water as a function of the molecular weight.

New immiscible refrigeration lubricant for HFCs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sunami, Motoshi; Takigawa, Katsuya; Suda, Satoshi

1995-12-31

This study examines the capability of a family of very low-viscosity alkylbenzenes (AB) used in high-side rotary compressors for HFCs. In the development of refrigeration lubricants for HFCs, miscibility is one of the most important problems to be solved. Therefore, PAG (polyalkylene glycols) and POE (polyol esters), which have good miscibility, have been applied in new HFC applications. However, it is difficult for these lubricants to maintain long-term durability in high-side rotary compressors. In friction tests under high HFC pressure, ABs with much lower viscosities than mineral oil maintained a much stronger oil film than the combination of mineral oil/R-12more » or POE/HFCs. These results were also proven by compressor durability tests. From the study of the solubility of ABs and HFCs, it is suggested that the total amount of refrigerant can be reduced because HFCs are barely soluble with ABs inside the high-side shell.« less

Miscible displacement of a non-Newtonian fluid in a capillary tube

NASA Astrophysics Data System (ADS)

Soori, Tejaswi; Ward, Thomas

2017-11-01

This talk focuses on experiments conducted to further our understanding of how to displace an aqueous polymer within a capillary tube (diameter < 1 mm) using a Newtonian fluid. Estimates of the residual film were measured as a function of Reynolds (Re), viscous Atwood (At) and Péclet (Pé) numbers. Aqueous polymers were prepared by mixing ϕ = 0.01-0.1% (wt/wt) Carboxymethyl Cellulose (CMC) in water. We measure the shear viscosity of the aqueous polymer over a broad range of shear rates and fit the data obtained to the Carreau fluid parameters. Separately we measure the average bulk diffusion coefficient of the aqueous polymer and water in water and aqueous polymer phases respectively. Previous studies on the immiscible displacement of polymers have shown residual film thickness to be dependent on the tube diameter. We will investigate if this is true when the two fluids are miscible in nature. American Chemical Society Petroleum Research Fund.

Oscillatory interfacial instability between miscible fluids

NASA Astrophysics Data System (ADS)

Shevtsova, Valentina; Gaponenko, Yuri; Mialdun, Aliaksandr; Torregrosa, Marita; Yasnou, Viktar

Interfacial instabilities occurring between two fluids are of fundamental interest in fluid dynamics, biological systems and engineering applications such as liquid storage, solvent extraction, oil recovery and mixing. Horizontal vibrations applied to stratified layers of immiscible liquids may generate spatially periodic waving of the interface, stationary in the reference frame of the vibrated cell, referred to as a "frozen wave". We present experimental evidence that frozen wave instability exists between two ordinary miscible liquids of similar densities and viscosities. At the experiments and at the numerical model, two superimposed layers of ordinary liquids, water-alcohol of different concentrations, are placed in a closed cavity in a gravitationally stable configuration. The density and viscosity of these fluids are somewhat similar. Similar to the immiscible fluids this instability has a threshold. When the value of forcing is increased the amplitudes of perturbations grow continuously displaying a saw-tooth structure. The decrease of gravity drastically changes the structure of frozen waves.

Ground-State Wave Function with Interactions between Different Species in M-Component Miscible Bose-Einstein Condensates

NASA Astrophysics Data System (ADS)

Kohno, Wataru; Kirikoshi, Akimitsu; Kita, Takafumi

2018-03-01

We construct a variational ground-state wave function of weakly interacting M-component Bose-Einstein condensates beyond the mean-field theory by incorporating the dynamical 3/2-body processes, where one of the two colliding particles drops into the condensate and vice versa. Our numerical results with various masses and particle numbers show that the 3/2-body processes between different particles make finite contributions to lowering the ground-state energy, implying that many-body correlation effects between different particles are essential even in the weak-coupling regime of the Bose-Einstein condensates. We also consider the stability condition for 2-component miscible states using the new ground-state wave function. Through this calculation, we obtain the relation UAB2/UAAUBB < 1 + α , where Uij is the effective contact potential between particles i and j and α is the correction, which originates from the 3/2- and 2-body processes.

Foreground Mitigation in the Epoch of Reionization

NASA Astrophysics Data System (ADS)

Chapman, Emma

2018-05-01

The EoR foregrounds can be up to three magnitudes greater than the cosmological signal we wish to detect. Multiple methods have been developed in order to extract the cosmological signal, falling roughly into three categories: foreground removal, foreground suppression and foreground avoidance. These main approaches are briefly discussed in this review and consideration taken to the future application of these methods as a multi-layered approach.

Multi-functional ultrathin Pd xCu 1-x and Pt~Pd xCu 1-x one-dimensional nanowire motifs for various small molecule oxidation reactions

DOE PAGES

Liu, Haiqing; Wong, Stanislaus S.; Adzic, Radoslav R.

2015-11-18

Developing novel electrocatalysts for small molecule oxidation processes, including formic acid oxidation (FAOR), methanol oxidation reaction (MOR), and ethanol oxidation reaction (EOR), denoting the key anodic reactions for their respective fuel cell configurations, is a significant and relevant theme of recent efforts in the field. Herein, in this report, we demonstrated a concerted effort to couple and combine the benefits of small size, anisotropic morphology, and tunable chemical composition in order to devise a novel “family” of functional architectures. In particular, we have fabricated not only ultrathin 1-D Pd 1–xCu x alloys but also Pt-coated Pd 1–xCu x (i.e., Pt~Pdmore » 1–xCu x; herein the ~ indicates an intimate association, but not necessarily actual bond formation, between the inner bimetallic core and the Pt outer shell) core–shell hierarchical nanostructures with readily tunable chemical compositions by utilizing a facile, surfactant-based, wet chemical synthesis coupled with a Cu underpotential deposition technique. Our main finding is that our series of as-prepared nanowires are functionally flexible. More precisely, we demonstrate that various examples within this “family” of structural motifs can be tailored for exceptional activity with all 3 of these important electrocatalytic reactions. In particular, we note that our series of Pd 1–xCu x nanowires all exhibit enhanced FAOR activities as compared with not only analogous Pd ultrathin nanowires but also commercial Pt and Pd standards, with Pd 9Cu representing the “optimal” composition. Moreover, our group of Pt~Pd 1–xCu x nanowires consistently outperformed not only commercial Pt NPs but also ultrathin Pt nanowires by several fold orders of magnitude for both the MOR and EOR reactions in alkaline media. As a result, the variation of the MOR and EOR performance with the chemical composition of our ultrathin Pt~Pd 1–xCu x nanowires was also discussed.« less

FOR STIMULI-RESPONSIVE POLYMERS WITH ENHANCED EFFICIENCY IN RESERVOIR RECOVERY PROCESSES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Charles McCormick; Roger Hester

To date, our synthetic research efforts have been focused on the development of stimuli-responsive water-soluble polymers designed for use in enhanced oil recovery (EOR) applications. These model systems are structurally tailored for potential application as viscosifiers and/or mobility control agents for secondary and tertiary EOR methods. The following report discloses the progress of our ongoing research of polyzwitterions, polymers derived from monomers bearing both positive and negative charges, that show the ability to sustain or increase their hydrodynamic volume (and thus, solution viscosity) in the presence of electrolytes. Such polymers appear to be well-suited for use under conditions similar tomore » those encountered in EOR operations. Additionally, we disclose the synthesis and characterization of a well-defined set of polyacrylamide (PAM) homopolymers that vary by MW. The MW of the PAM samples is controlled by addition of sodium formate to the polymerization medium as a conventional chain transfer agent. Data derived from polymer characterization is used to determine the kinetic parameter C{sub CT}, the chain transfer constant to sodium formate under the given polymerization conditions. The PAM homopolymer series will be employed in future set of experiments designed to test a simplified intrinsic viscosity equation. The flow resistance of a polymer solution through a porous medium is controlled by the polymer's hydrodynamic volume, which is strongly related to it's intrinsic viscosity. However, the hydrodynamic volume of a polymer molecule in an aqueous solution varies with fluid temperature, solvent composition, and polymer structure. This report on the theory of polymer solubility accentuates the importance of developing polymer solutions that increase in intrinsic viscosity when fluid temperatures are elevated above room conditions. The intrinsic viscosity response to temperature and molecular weight variations of three polymer solutions verified the modeling capability of a simplified intrinsic viscosity equation. These results imply that the simplified intrinsic viscosity equation is adequate in modeling polymer coil size response to solvent composition, temperature and polymer molecular weight. The equation can be used to direct efforts to produce superior polymers for mobility control during flooding of reservoirs at elevated temperatures.« less

THE IMPACT OF THE IONOSPHERE ON GROUND-BASED DETECTION OF THE GLOBAL EPOCH OF REIONIZATION SIGNAL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sokolowski, Marcin; Wayth, Randall B.; Tremblay, Steven E.

2015-11-01

The redshifted 21 cm line of neutral hydrogen (H i), potentially observable at low radio frequencies (∼50–200 MHz), is a promising probe of the physical conditions of the intergalactic medium during Cosmic Dawn and the Epoch of Reionization (EoR). The sky-averaged H i signal is expected to be extremely weak (∼100 mK) in comparison to the Galactic foreground emission (∼10{sup 4} K). Moreover, the sky-averaged spectra measured by ground-based instruments are affected by chromatic propagation effects (∼tens of kelvin) originating in the ionosphere. We analyze data collected with the upgraded Broadband Instrument for Global Hydrogen Reionization Signal system deployed atmore » the Murchison Radio-astronomy Observatory to assess the significance of ionospheric effects on the detection of the global EoR signal. The ionospheric effects identified in these data are, particularly during nighttime, dominated by absorption and emission. We measure some properties of the ionosphere, such as the electron temperature (T{sub e} ≈ 470 K at nighttime), magnitude, and variability of optical depth (τ{sub 100} {sub MHz} ≈ 0.01 and δτ ≈ 0.005 at nighttime). According to the results of a statistical test applied on a large data sample, very long integrations (∼100 hr collected over approximately 2 months) lead to increased signal-to-noise ratio even in the presence of ionospheric variability. This is further supported by the structure of the power spectrum of the sky temperature fluctuations, which has flicker noise characteristics at frequencies ≳10{sup −5} Hz, but becomes flat below ≈10{sup −5} Hz. Hence, we conclude that the stochastic error introduced by the chromatic ionospheric effects tends to zero in an average. Therefore, the ionospheric effects and fluctuations are not fundamental impediments preventing ground-based instruments from integrating down to the precision required by global EoR experiments, provided that the ionospheric contribution is properly accounted for in the data analysis.« less

Very High-Risk Localized Prostate Cancer: Outcomes Following Definitive Radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Narang, Amol K.; Gergis, Carol; Robertson, Scott P.

Purpose: Existing definitions of high-risk prostate cancer consist of men who experience significant heterogeneity in outcomes. As such, criteria that identify a subpopulation of National Comprehensive Cancer Network (NCCN) high-risk prostate cancer patients who are at very high risk (VHR) for poor survival outcomes following prostatectomy were recently developed at our institution and include the presence of any of the following disease characteristics: multiple NCCN high-risk factors, primary Gleason pattern 5 disease and/or ≥5 biopsy cores with Gleason sums of 8 to 10. Whether these criteria also apply to men undergoing definitive radiation is unclear, as is the optimal treatment regimenmore » in these patients. Methods and Materials: All men consecutively treated with definitive radiation by a single provider from 1993 to 2006 and who fulfilled criteria for NCCN high-risk disease were identified (n=288), including 99 patients (34%) with VHR disease. Multivariate-adjusted competing risk regression models were constructed to assess associations between the VHR definition and biochemical failure (BF), distant metastasis (DM), and prostate cancer–specific mortality (PCSM). Multivariate-adjusted Cox regression analysis assessed the association of the VHR definition with overall mortality (OM). Cumulative incidences of failure endpoints were compared between VHR men and other NCCN high-risk men. Results: Men with VHR disease compared to other NCCN high-risk men experienced a higher 10-year incidence of BF (54.0% vs 35.4%, respectively, P<.001), DM (34.9% vs 13.4%, respectively, P<.001), PCSM (18.5% vs 5.9%, respectively, P<.001), and OM (36.4% vs 27.0%, respectively, P=.04). VHR men with a detectable prostate-specific antigen (PSA) concentration at the end of radiation (EOR) remained at high risk of 10-year PCSM compared to VHR men with an undetectable EOR PSA (31.0% vs 13.7%, respectively, P=.05). Conclusions: NCCN high-risk prostate cancer patients who meet VHR criteria experience distinctly worse outcomes following definitive radiation and long-term androgen deprivation therapy, particularly if an EOR PSA is detectable. Optimal use of local therapies for VHR patients should be explored further, as should novel agents.« less

Synthesis and evaluation of novel siloxane-methacrylate monomers used as dentin adhesives

PubMed Central

Ge, Xueping; Ye, Qiang; Song, Linyong; Misra, Anil; Spencer, Paulette

2014-01-01

Objectives The objectives of this study were to synthesize two new siloxane-methacrylate (SM) monomers for application in dentin adhesives and to investigate the influence of different functionality of the siloxane-containing monomers on the adhesive photopolymerization, water sorption, and mechanical properties. Materials and method Two siloxane-methacrylate monomers (SM1 and SM2) with four and eight methacrylate groups were synthesized. Dentin adhesives containing BisGMA, HEMA and the siloxane-methacrylate monomers were photo-polymerized. The experimental adhesives were compared with the control adhesive (HEMA/BisGMA 45/55 w/w) and characterized with regard to degree of conversion (DC), water miscibility of the liquid resin, water sorption and dynamic mechanical analysis (DMA). Results The experimental adhesives exhibited improved water miscibility as compared to the control. When cured in the presence of 12 wt % water to simulate the wet environment of the mouth, the SM-containing adhesives showed DC comparable to the control. The experimental adhesives showed higher rubbery modulus than the control under dry conditions. Under wet conditions, the mechanical properties of the formulations containing SM monomer with increased functionality were comparable with the control, even with more water sorption. Significance The concentration and functionality of the newly synthesized siloxane-methacrylate monomers affected the water miscibility, water sorption and mechanical properties of the adhesives. The experimental adhesives show improved water compatibility compared with the control. The mechanical properties were enhanced with an increase of the functionality of the siloxane-containing monomers. The results provide critical structure/property relationships and important information for future development of durable, versatile siloxane-containing dentin adhesives. PMID:24993811

A new method to simulate the effects of viscous fingering on miscible displacement processes in porous media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vossoughi, S.; Green, D.W.; Smith, J.E.

Dispersion and viscous fingering are important parameters in miscible displacement. Effects of dispersion on concentration profiles in porous media can be simulated when the viscosity ratio is favorable. The capability to simulate viscous fingering is limited. This paper presents a new method to simulate effects of viscous fingering on miscible displacement processes in porous media. The method is based on the numerical solution of a general form of the convection-dispersion equation. In this equation the convection term is represented by a fractional flow function. The fractional flow function is derived from Darcy's law by using a concentration-dependent average viscosity andmore » relative flow area to each fluid at any point in the bed. The method was extended to the description of a polymer flood by including retention and inaccessible PV. A Langmuir-type model for polymer retention in the rock was used. The resulting convection-dispersion equation for displacement by polymer was solved numerically by the use of a finite-element method with linear basis functions and Crank-Nicholson derivative approximation. History matches were performed on four sets of laboratory data to verify the model: (1) an unfavorable viscosity ratio displacement, (2) stable displacement of glycerol by polymer solution, (3) unstable displacement of brine by a slug of polymer solution, and (4) a favorable viscosity ratio displacement. In general, computed results from the model matched laboratory data closely. Good agreement of the model with experiments over a significant range of variables lends support to the analysis.« less

Nonequilibrium Interfacial Tension in Simple and Complex Fluids

NASA Astrophysics Data System (ADS)

Truzzolillo, Domenico; Mora, Serge; Dupas, Christelle; Cipelletti, Luca

2016-10-01

Interfacial tension between immiscible phases is a well-known phenomenon, which manifests itself in everyday life, from the shape of droplets and foam bubbles to the capillary rise of sap in plants or the locomotion of insects on a water surface. More than a century ago, Korteweg generalized this notion by arguing that stresses at the interface between two miscible fluids act transiently as an effective, nonequilibrium interfacial tension, before homogenization is eventually reached. In spite of its relevance in fields as diverse as geosciences, polymer physics, multiphase flows, and fluid removal, experiments and theoretical works on the interfacial tension of miscible systems are still scarce, and mostly restricted to molecular fluids. This leaves crucial questions unanswered, concerning the very existence of the effective interfacial tension, its stabilizing or destabilizing character, and its dependence on the fluid's composition and concentration gradients. We present an extensive set of measurements on miscible complex fluids that demonstrate the existence and the stabilizing character of the effective interfacial tension, unveil new regimes beyond Korteweg's predictions, and quantify its dependence on the nature of the fluids and the composition gradient at the interface. We introduce a simple yet general model that rationalizes nonequilibrium interfacial stresses to arbitrary mixtures, beyond Korteweg's small gradient regime, and show that the model captures remarkably well both our new measurements and literature data on molecular and polymer fluids. Finally, we briefly discuss the relevance of our model to a variety of interface-driven problems, from phase separation to fracture, which are not adequately captured by current approaches based on the assumption of small gradients.

Synthesis and evaluation of novel siloxane-methacrylate monomers used as dentin adhesives.

PubMed

Ge, Xueping; Ye, Qiang; Song, Linyong; Misra, Anil; Spencer, Paulette

2014-09-01

The objectives of this study were to synthesize two new siloxane-methacrylate (SM) monomers for application in dentin adhesives and to investigate the influence of different functionality of the siloxane-containing monomers on the adhesive photopolymerization, water sorption, and mechanical properties. Two siloxane-methacrylate monomers (SM1 and SM2) with four and eight methacrylate groups were synthesized. Dentin adhesives containing BisGMA, HEMA and the siloxane-methacrylate monomers were photo-polymerized. The experimental adhesives were compared with the control adhesive (HEMA/BisGMA, 45/55, w/w) and characterized with regard to degree of conversion (DC), water miscibility of the liquid resin, water sorption and dynamic mechanical analysis (DMA). The experimental adhesives exhibited improved water miscibility as compared to the control. When cured in the presence of 12 wt% water to simulate the wet environment of the mouth, the SM-containing adhesives showed DC comparable to the control. The experimental adhesives showed higher rubbery modulus than the control under dry conditions. Under wet conditions, the mechanical properties of the formulations containing SM monomer with increased functionality were comparable with the control, even with more water sorption. The concentration and functionality of the newly synthesized siloxane-methacrylate monomers affected the water miscibility, water sorption and mechanical properties of the adhesives. The experimental adhesives show improved water compatibility compared with the control. The mechanical properties were enhanced with an increase of the functionality of the siloxane-containing monomers. The results provide critical structure/property relationships and important information for future development of durable, versatile siloxane-containing dentin adhesives. Published by Elsevier Ltd.

Physicochemical properties of film-coated melt-extruded pellets.

PubMed

Young, Chistopher R; Crowley, Michael; Dietzsch, Caroline; McGinity, James W

2007-02-01

The purpose of this study was to investigate the physicochemical properties of poly(ethylene oxide) (PEO) and guaifenesin containing beads prepared by a melt-extrusion process and film-coated with a methacrylic acid copolymer. Solubility parameter calculations, thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), modulated differential scanning calorimetry (MDSC), X-ray powder diffraction (XRPD) and high performance liquid chromatography (HPLC) were used to determine drug/polymer miscibility and/or the thermal processibility of the systems. Powder blends of guaifenesin, PEO and functional excipients were processed using a melt-extrusion and spheronization technique and then film-coated in a fluidized bed apparatus. Solubility parameter calculations were used to predict miscibility between PEO and guaifenesin, and miscibility was confirmed by SEM and observation of a single melting point for extruded drug/polymer blends during MDSC investigations. The drug was stable following melt-extrusion as determined by TGA and HPLC; however, drug release rate from pellets decreased upon storage in sealed HDPE containers with silica desiccants at 40 degrees C/75% RH. The weight loss on drying, porosity and tortuosity determinations were not influenced by storage. Recrystallization of guaifenesin and PEO was confirmed by SEM and XRPD. Additionally, the pellets exhibited a change in adhesion behaviour during dissolution testing. The addition of ethylcellulose to the extruded powder blend decreased and stabilized the drug release rate from the thermally processed pellets. The current study also demonstrated film-coating to be an efficient process for providing melt-extruded beads with pH-dependent drug release properties that were stable upon storage at accelerated conditions.

Entropic depletion in colloidal suspensions and polymer liquids: Role of nanoparticle surface topography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Banerjee, Debapriya; Yang, Jian; Schweizer, Kenneth S.

2015-01-01

Here, we employ a hybrid Monte Carlo plus integral equation theory approach to study how dense fluids of small nanoparticles or polymer chains mediate entropic depletion interactions between topographically rough particles where all interaction potentials are hard core repulsion. The corrugated particle surfaces are composed of densely packed beads which present variable degrees of controlled topographic roughness and free volume associated with their geometric crevices. This pure entropy problem is characterized by competing ideal translational and (favorable and unfavorable) excess entropic contributions. Surface roughness generically reduces particle depletion aggregation relative to the smooth hard sphere case. However, the competition betweenmore » ideal and excess packing entropy effects in the bulk, near the particle surface and in the crevices, results in a non-monotonic variation of the particle-monomer packing correlation function as a function of the two dimensionless length scale ratios that quantify the effective surface roughness. As a result, the inter-particle potential of mean force (PMF), second virial coefficient, and spinodal miscibility volume fraction vary non-monotonically with the surface bead to monomer diameter and particle core to surface bead diameter ratios. A miscibility window is predicted corresponding to an optimum degree of surface roughness that completely destroys depletion attraction resulting in a repulsive PMF. Variation of the (dense) matrix packing fraction can enhance or suppress particle miscibility depending upon the amount of surface roughness. Connecting the monomers into polymer chains destabilizes the system via enhanced contact depletion attraction, but the non-monotonic variations with surface roughness metrics persist.« less

Thermodynamic properties of hematite — ilmenite — geikielite solid solutions

NASA Astrophysics Data System (ADS)

Ghiorso, Mark S.

1990-11-01

A solution model is developed for rhombohedral oxide solid solutions having compositions within the ternary system ilmenite [(Fe{2+/ s }Ti{4+/1- s }) A (Fe{2+/1- s }Ti{4+/s}) B O3]-geikielite [(Mg{2+/ t }Ti{4+/1- t }) A (Mg{2+/1- t }Ti{4+/ t }) B O3]-hematite [(Fe3+) A (Fe3+) B O3]. The model incorporates an expression for the configurational entropy of solution, which accounts for varying degrees of structural long-range order (0≤s, t≤1) and utilizes simple regular solution theory to characterize the excess Gibbs free energy of mixing within the five-dimensional composition-ordering space. The 13 model parameters are calibrated from available data on: (1) the degree of long-range order and the composition-temperature dependence of theRbar 3c - Rbar 3 transition along the ilmenite-hematite binary join; (2) the compositions of coexisting olivine and rhombohedral oxide solid solutions close to the Mg-Fe2+ join; (3) the shape of the miscibility gap along the ilmenite-hematite join; (4) the compositions of coexisting spinel and rhombohedral oxide solid solutions along the Fe2+-Fe3+ join. In the course of calibration, estimates are obtained for the reference state enthalpy of formation of ulvöspinel and stoichiometric hematite (-1488.5 and -822.0 kJ/mol at 298 K and 1 bar, respectively). The model involves no excess entropies of mixing nor does it incorporate ternary interaction parameters. The formulation fits the available data and represents an internally consistent energetic model when used in conjuction with the standard state thermodynamic data set of Berman (1988) and the solution theory for orthopyroxenes, olivines and Fe-Mg titanomagnetite-aluminate-chromate spinels developed by Sack and Ghiorso (1989, 1990a, b). Calculated activity-composition relations for the end-members of the series, demonstrate the substantial degree of nonideality associated with interactions between the ordered and disordered structures and the dominant influence of the miscibility gap across much of the ternary system. The predicted shape of the miscibility gap, and the orientation of tie-lines relating the compositions of coexisting phases, display the effects of coupling between the excess enthalpy of solution and the degree of long-range order. One limb of the miscibility gap follows the composititiontemperature surface corresponding to the ternaryRbar 3 - Rbar 3c second-order transition.

Field-scale simulation of chemical flooding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saad, N.

1989-01-01

A three-dimensional compositional chemical flooding simulator (UTCHEM) has been improved. The new mathematical formulation, boundary conditions, and a description of the physicochemical models of the simulator are presented. This improved simulator has been used for the study of the low tension pilot project at the Big Muddy field near Casper, Wyoming. Both the tracer injection conducted prior to the injection of the chemical slug, and the chemical flooding stages of the pilot project, have been analyzed. Not only the oil recovery but also the tracers, polymer, alcohol and chloride histories have been successfully matched with field results. Simulation results indicatemore » that, for this fresh water reservoir, the salinity gradient during the preflush and the resulting calcium pickup by the surfactant slug played a major role in the success of the project. In addition, analysis of the effects of the crossflow on the performance of the pilot project indicates that, for the well spacing of the pilot, crossflow does not play as important a role as it might for a large-scale project. To improve the numerical efficiency of the simulator, a third order convective differencing scheme has been applied to the simulator. This method can be used with non-uniform mesh, and therefore is suited for simulation studies of large-scale multiwell heterogeneous reservoirs. Comparison of the results with one and two dimensional analytical solutions shows that this method is effective in eliminating numerical dispersion using relatively large grid blocks. Results of one, two and three-dimensional miscible water/tracer flow, water flooding, polymer flooding, and micellar-polymer flooding test problems, and results of grid orientation studies, are presented.« less

EOR production technique tested on Codell

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stremel, K.

1983-05-01

A production method of natural gas that eliminated marketing problems and allowed maximum recovery was dicussed. The method involved the dehydration of the gas, stripping of the propane and butane products, and the compression and reinjection of the dry gas to the well. This maintenance of pressure will allow storage of the gas until marketing conditions improve. The production method is being tested at pilot wells in Colorado by Petromax Energy Corporation.

Defects and Interfaces on PtPb Nanoplates Boost Fuel Cell Electrocatalysis.

PubMed

Sun, Yingjun; Liang, Yanxia; Luo, Mingchuan; Lv, Fan; Qin, Yingnan; Wang, Lei; Xu, Chuan; Fu, Engang; Guo, Shaojun

2018-01-01

Nanostructured Pt is the most efficient single-metal catalyst for fuel cell technology. Great efforts have been devoted to optimizing the Pt-based alloy nanocrystals with desired structure, composition, and shape for boosting the electrocatalytic activity. However, these well-known controls still show the limited ability in maximizing the Pt utilization efficiency for achieving more efficient fuel cell catalysis. Herein, a new strategy for maximizing the fuel cell catalysis by controlling/tuning the defects and interfaces of PtPb nanoplates using ion irradiation technique is reported. The defects and interfaces on PtPb nanoplates, controlled by the fluence of incident C + ions, make them exhibit the volcano-like electrocatalytic activity for methanol oxidation reaction (MOR), ethanol oxidation reaction (EOR), and oxygen reduction reaction (ORR) as a function of ion irradiation fluence. The optimized PtPb nanoplates with the mixed structure of dislocations, subgrain boundaries, and small amorphous domains are the most active for MOR, EOR, and ORR. They can also maintain high catalytic stability in acid solution. This work highlights the impact and significance of inducing/controlling the defects and interfaces on Pt-based nanocrystals toward maximizing the catalytic performance by advanced ion irradiation strategy. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simulation Study of CO2-EOR in Tight Oil Reservoirs with Complex Fracture Geometries

PubMed Central

Zuloaga-Molero, Pavel; Yu, Wei; Xu, Yifei; Sepehrnoori, Kamy; Li, Baozhen

2016-01-01

The recent development of tight oil reservoirs has led to an increase in oil production in the past several years due to the progress in horizontal drilling and hydraulic fracturing. However, the expected oil recovery factor from these reservoirs is still very low. CO2-based enhanced oil recovery is a suitable solution to improve the recovery. One challenge of the estimation of the recovery is to properly model complex hydraulic fracture geometries which are often assumed to be planar due to the limitation of local grid refinement approach. More flexible methods like the use of unstructured grids can significantly increase the computational demand. In this study, we introduce an efficient methodology of the embedded discrete fracture model to explicitly model complex fracture geometries. We build a compositional reservoir model to investigate the effects of complex fracture geometries on performance of CO2 Huff-n-Puff and CO2 continuous injection. The results confirm that the appropriate modelling of the fracture geometry plays a critical role in the estimation of the incremental oil recovery. This study also provides new insights into the understanding of the impacts of CO2 molecular diffusion, reservoir permeability, and natural fractures on the performance of CO2-EOR processes in tight oil reservoirs. PMID:27628131

Sensitivity of the Hydrogen Epoch of Reionization Array and its build-out stages to one-point statistics from redshifted 21 cm observations

NASA Astrophysics Data System (ADS)

Kittiwisit, Piyanat; Bowman, Judd D.; Jacobs, Daniel C.; Beardsley, Adam P.; Thyagarajan, Nithyanandan

2018-03-01

We present a baseline sensitivity analysis of the Hydrogen Epoch of Reionization Array (HERA) and its build-out stages to one-point statistics (variance, skewness, and kurtosis) of redshifted 21 cm intensity fluctuation from the Epoch of Reionization (EoR) based on realistic mock observations. By developing a full-sky 21 cm light-cone model, taking into account the proper field of view and frequency bandwidth, utilizing a realistic measurement scheme, and assuming perfect foreground removal, we show that HERA will be able to recover statistics of the sky model with high sensitivity by averaging over measurements from multiple fields. All build-out stages will be able to detect variance, while skewness and kurtosis should be detectable for HERA128 and larger. We identify sample variance as the limiting constraint of the measurements at the end of reionization. The sensitivity can also be further improved by performing frequency windowing. In addition, we find that strong sample variance fluctuation in the kurtosis measured from an individual field of observation indicates the presence of outlying cold or hot regions in the underlying fluctuations, a feature that can potentially be used as an EoR bubble indicator.

Epoch of Reionisation

NASA Astrophysics Data System (ADS)

Barry, N.; Beardsley, A.; Bowman, J.; Briggs, F.; Byrne, R.; Carroll, P.; Hazelton, B.; Jacobs, D.; Jordan, C.; Kittiwisit, P.; Lanman, A.; Lenc, E.; Li, W.; Line, J.; McKinley, B.; Mitchell, D.; Morales, M.; Murray, S.; Paul, S.; Pindor, B.; Pober, J.; Rahimi, M.; Riding, J.; Sethi, S.; Shankar, U.; Subrahmanyan, R.; Sullivan, I.; Takahashi, K.; Thyagarajan, N.; Tingay, S.; Trott, C.; Wayth, R.; Webster, R.; Wyithe, S.

2017-01-01

The Murchison Widefield Array is designed to measure the fluctuations in the 21cm emission from neutral hydrogen during the Epoch of Reionisation. The new hex configuration is explicitly designed to test the predicted increase in sensitivity of redundant baselines. However the challenge of the new array is to understand calibration with the new configuration. We have developed two new pipelines to reduce the hex data, and will compare the results with previous datasets from the Phase 1 array. We have now processed 80 hours of data refining the data analysis through our two established Phase 1 pipelines. This proposal requests as much observing time as possible in semester 2017-A to (1) obtain a comparable hex dataset to test the sensitivity and systematic limits with redundant arrays, (2) establish the optimal observing strategy for an EoR detection, and (3) continue to explore observational strategies in the three EoR fields to advise the design of SKA-low experiments. Due to the proposed changes in the array during the upcoming semester, we have not requested a specific number of hours, but will optimise our observing program as availability of the telescope becomes clear. We note that this observing proposal implements the key scientific program that can benefit from the new hex configuration.

Enhancing Condom Use Among Black Male Youths: A Randomized Controlled Trial

PubMed Central

Charnigo, Richard J.; Salazar, Laura F.; Pasternak, Ryan; Terrell, Ivy W.; Ricks, JaNelle; Smith, Rachel V.; Taylor, Stephanie N.

2014-01-01

Objectives. We tested the efficacy of a brief intervention to promote correct and consistent use of condoms among Black male youths attending sexually transmitted infection (STI) clinics in 3 southern US cities. Methods. In 2010 to 2012, we screened (n = 1102) and enrolled (n = 702) youths aged 15 to 23 years who identified as Black and reported recent (past 2 months) sexual activity and randomized them to a private, brief, interactive intervention (n = 349) or an attention-equivalent control condition (n = 353). Assessments occurred at baseline and 2 and 6 months after the intervention. Results. At 6 months, with adjustment for age and pretest nonequivalence of the outcome variable, an estimated odds ratio (EOR) of 1.63 (95% confidence interval [CI] = 1.07, 2.49; P = .02) indicated efficacy for correct condom use. An adjusted generalized estimating equations model with both 2- and 6-month condom use variables produced an EOR of 1.49 (95% CI = 1.06, 2.08; P = .02). We did not observe significant effects on chlamydia and gonorrhea incidence. Conclusions. This brief intervention, delivered as part of STI clinical care, could help alleviate the disproportionate STI–HIV burden among young Black men. PMID:25211749

Electrochemical activity evaluation of chemically damaged carbon nanotube with palladium nanoparticles for ethanol oxidation

NASA Astrophysics Data System (ADS)

Ahmed, Mohammad Shamsuddin; Jeon, Seungwon

2015-05-01

The carbon nanotube (CNT) has unique electrical and structural properties due to it's sp2 π-conjugative structure that leads to the higher electrocatalysis. The π-conjugative structure, that allows the CNT interact with various compounds and metal nanoparticles (NPs) through π-π electronic interaction. However, the damage of π-conjugative sidewall of CNT that can be hinder the electrocatalytic activity has found. For this study, the CNT, as base material, has been prepared through a conventional acid treatment method up to 15 h; the higher degree of sidewall damage has been observed in last 5 h during treatment period. The short and long term acid treated (denoted as CNT and CNT-COOH, respectively) CNTs have been subsequently fabricated with palladium NPs (denoted as CNT/Pd and CNT-Pd, respectively) and employed as ethanol oxidation reaction (EOR) catalysts. The CNT-Pd displays a poor electrocatalytic performance towards EOR than that of CNT/Pd due to the damage of π-conjugative sidewall. The kinetic parameters including poisoning tolerance have also been hampered by the surface damage. The CNT/Pd (∼3.3 folds) and CNT-Pd (∼1.5 folds) are express higher electrocatalytic activity and poisoning tolerance than that of Pd/C while Pd mass loading remains in the same amount.

PRECISE MEASUREMENT OF THE REIONIZATION OPTICAL DEPTH FROM THE GLOBAL 21 cm SIGNAL ACCOUNTING FOR COSMIC HEATING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fialkov, Anastasia; Loeb, Abraham, E-mail: anastasia.fialkov@cfa.harvard.edu, E-mail: aloeb@cfa.harvard.edu

2016-04-10

As a result of our limited data on reionization, the total optical depth for electron scattering, τ, limits precision measurements of cosmological parameters from the Cosmic Microwave Background (CMB). It was recently shown that the predicted 21 cm signal of neutral hydrogen contains enough information to reconstruct τ with sub-percent accuracy, assuming that the neutral gas was much hotter than the CMB throughout the entire epoch of reionization (EoR). Here we relax this assumption and use the global 21 cm signal alone to extract τ for realistic X-ray heating scenarios. We test our model-independent approach using mock data for amore » wide range of ionization and heating histories and show that an accurate measurement of the reionization optical depth at a sub-percent level is possible in most of the considered scenarios even when heating is not saturated during the EoR, assuming that the foregrounds are mitigated. However, we find that in cases where heating sources had hard X-ray spectra and their luminosity was close to or lower than what is predicted based on low-redshift observations, the global 21 cm signal alone is not a good tracer of the reionization history.« less

Production, Characterization, and Application of Bacillus licheniformis W16 Biosurfactant in Enhancing Oil Recovery.

PubMed

Joshi, Sanket J; Al-Wahaibi, Yahya M; Al-Bahry, Saif N; Elshafie, Abdulkadir E; Al-Bemani, Ali S; Al-Bahri, Asma; Al-Mandhari, Musallam S

2016-01-01

The biosurfactant production by Bacillus licheniformis W16 and evaluation of biosurfactant based enhanced oil recovery (EOR) using core-flood under reservoir conditions were investigated. Previously reported nine different production media were screened for biosurfactant production, and two were further optimized with different carbon sources (glucose, sucrose, starch, cane molasses, or date molasses), as well as the strain was screened for biosurfactant production during the growth in different media. The biosurfactant reduced the surface tension and interfacial tension to 24.33 ± 0.57 mN m -1 and 2.47 ± 0.32 mN m -1 respectively within 72 h, at 40°C, and also altered the wettability of a hydrophobic surface by changing the contact angle from 55.67 ± 1.6 to 19.54°± 0.96°. The critical micelle dilution values of 4X were observed. The biosurfactants were characterized by different analytical techniques and identified as lipopeptide, similar to lichenysin-A. The biosurfactant was stable over wide range of extreme environmental conditions. The core flood experiments showed that the biosurfactant was able to enhance the oil recovery by 24-26% over residual oil saturation (S or ). The results highlight the potential application of lipopeptide biosurfactant in wettability alteration and microbial EOR processes.

Applicability of anaerobic nitrate-dependent Fe(II) oxidation to microbial enhanced oil recovery (MEOR).

PubMed

Zhu, Hongbo; Carlson, Han K; Coates, John D

2013-08-06

Microbial processes that produce solid-phase minerals could be judiciously applied to modify rock porosity with subsequent alteration and improvement of floodwater sweep in petroleum reservoirs. However, there has been little investigation of the application of this to enhanced oil recovery (EOR). Here, we investigate a unique approach of altering reservoir petrology through the biogenesis of authigenic rock minerals. This process is mediated by anaerobic chemolithotrophic nitrate-dependent Fe(II)-oxidizing microorganisms that precipitate iron minerals from the metabolism of soluble ferrous iron (Fe(2+)) coupled to the reduction of nitrate. This mineral biogenesis can result in pore restriction and reduced pore throat diameter. Advantageously and unlike biomass plugs, these biominerals are not susceptible to pressure or thermal degradation. Furthermore, they do not require continual substrate addition for maintenance. Our studies demonstrate that the biogenesis of insoluble iron minerals in packed-bed columns results in effective hydrology alteration and homogenization of heterogeneous flowpaths upon stimulated microbial Fe(2+) biooxidation. We also demonstrate almost 100% improvement in oil recovery from hydrocarbon-saturated packed-bed columns as a result of this metabolism. These studies represent a novel departure from traditional microbial EOR approaches and indicate the potential for nitrate-dependent Fe(2+) biooxidation to improve volumetric sweep efficiency and enhance both the quality and quantity of oil recovered.

Study on the reutilization of clear fracturing flowback fluids in surfactant flooding with additives for Enhanced Oil Recovery (EOR).

PubMed

Dai, Caili; Wang, Kai; Liu, Yifei; Fang, Jichao; Zhao, Mingwei

2014-01-01

An investigation was conducted to study the reutilization of clear fracturing flowback fluids composed of viscoelastic surfactants (VES) with additives in surfactant flooding, making the process more efficient and cost-effective. The clear fracturing flowback fluids were used as surfactant flooding system with the addition of α-olefin sulfonate (AOS) for enhanced oil recovery (EOR). The interfacial activity, emulsification activity and oil recovery capability of the recycling system were studied. The interfacial tension (IFT) between recycling system and oil can be reduced by 2 orders of magnitude to 10(-3) mN/m, which satisfies the basic demand of surfactant flooding. The oil can be emulsified and dispersed more easily due to the synergetic effect of VES and AOS. The oil-wet surface of quartz can be easily converted to water-wet through adsorption of surfactants (VES/AOS) on the surface. Thirteen core plug flooding tests were conducted to investigate the effects of AOS concentrations, slug sizes and slug types of the recycling system on the incremental oil recovery. The investigations prove that reclaiming clear fracturing flowback fluids after fracturing operation and reuse it in surfactant flooding might have less impact on environment and be more economical.

Blind Spectroscopic Galaxy Surveys Using an Ultra-Wide-Band Imaging Spectrograph on AtLAST and LST

NASA Astrophysics Data System (ADS)

Kohno, Kotaro

2018-01-01

A novel approach to elucidation of cosmic star formation history is a blind search for CO and [CII] emissions using a ultra-wide-band imaging spectrograph on the future large submm telescopes like AtLAST and LST. In particular, searching for [CII] emitters in the appropriate frequency range allows us to sample those sources very efficiently for a redshift range of 3.5 to 9 (190 to 420 GHz), reaching the star-formation in the EoR. Further, spectroscopic analysis of CO in the lower frequency bands will constrain the evolution of CO luminosity functions across cosmic time. We conducted a feasibility study of ``CO/[CII] tomography'' based on a mock galaxy catalog containing 1.4 million objects drawn from the S(3) -SAX (Obreschkow et al. 2009). We find that a blind spectroscopic survey using a 50-m telescope equipped with a 100-pixel imaging spectrograph, which covers 70-370 GHz simultaneously, will be promising indeed. A survey of 2 deg(2) in 1,000 hr (on-source) will uncover > 10^5 line-emitting galaxies in total, including 10^3 [CII] emitters in the EoR (Tamura et al., in prep.). Wider surveys (10 deg^2 or wider) will also be discussed for RSD science cases.

Study on the Reutilization of Clear Fracturing Flowback Fluids in Surfactant Flooding with Additives for Enhanced Oil Recovery (EOR)

PubMed Central

Dai, Caili; Wang, Kai; Liu, Yifei; Fang, Jichao; Zhao, Mingwei

2014-01-01

An investigation was conducted to study the reutilization of clear fracturing flowback fluids composed of viscoelastic surfactants (VES) with additives in surfactant flooding, making the process more efficient and cost-effective. The clear fracturing flowback fluids were used as surfactant flooding system with the addition of α-olefin sulfonate (AOS) for enhanced oil recovery (EOR). The interfacial activity, emulsification activity and oil recovery capability of the recycling system were studied. The interfacial tension (IFT) between recycling system and oil can be reduced by 2 orders of magnitude to 10−3 mN/m, which satisfies the basic demand of surfactant flooding. The oil can be emulsified and dispersed more easily due to the synergetic effect of VES and AOS. The oil-wet surface of quartz can be easily converted to water-wet through adsorption of surfactants (VES/AOS) on the surface. Thirteen core plug flooding tests were conducted to investigate the effects of AOS concentrations, slug sizes and slug types of the recycling system on the incremental oil recovery. The investigations prove that reclaiming clear fracturing flowback fluids after fracturing operation and reuse it in surfactant flooding might have less impact on environment and be more economical. PMID:25409507

Using low-frequency pulsar observations to study the 3-D structure of the Galactic magnetic field

NASA Astrophysics Data System (ADS)

Sobey, C.; LOFAR Collaboration; MWA Collaboration

2018-05-01

The Galactic magnetic field (GMF) plays a role in many astrophysical processes and is a significant foreground to cosmological signals, such as the Epoch of Reionization (EoR), but is not yet well understood. Dispersion and Faraday rotation measurements (DMs and RMs, respectively) towards a large number of pulsars provide an efficient method to probe the three-dimensional structure of the GMF. Low-frequency polarisation observations with large fractional bandwidth can be used to measure precise DMs and RMs. This is demonstrated by a catalogue of RMs (corrected for ionospheric Faraday rotation) from the Low Frequency Array (LOFAR), with a growing complementary catalogue in the southern hemisphere from the Murchison Widefield Array (MWA). These data further our knowledge of the three-dimensional GMF, particularly towards the Galactic halo. Recently constructed or upgraded pathfinder and precursor telescopes, such as LOFAR and the MWA, have reinvigorated low-frequency science and represent progress towards the construction of the Square Kilometre Array (SKA), which will make significant advancements in studies of astrophysical magnetic fields in the future. A key science driver for the SKA-Low is to study the EoR, for which pulsar and polarisation data can provide valuable insights in terms of Galactic foreground conditions.

ENHANCING RESERVOIR MANAGEMENT IN THE APPALACHIAN BASIN BY IDENTIFYING TECHNICAL BARRIER AND PREFERRED PRACTICES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ronald R. McDowell; Khashayar Aminian; Katharine L. Avary

2003-09-01

The Preferred Upstream Management Practices (PUMP) project, a two-year study sponsored by the United States Department of Energy (USDOE), had three primary objectives: (1) the identification of problems, problematic issues, potential solutions and preferred practices related to oil production; (2) the creation of an Appalachian Regional Council to oversee and continue this investigation beyond the end of the project; and (3) the dissemination of investigative results to the widest possible audience, primarily by means of an interactive website. Investigation and identification of oil production problems and preferred management practices began with a Problem Identification Workshop in January of 2002. Threemore » general issues were selected by participants for discussion: Data Management; Reservoir Engineering; and Drilling Practices. At the same meeting, the concept of the creation of an oversight organization to evaluate and disseminated preferred management practices (PMP's) after the end of the project was put forth and volunteers were solicited. In-depth interviews were arranged with oil producers to gain more insight into problems and potential solutions. Project members encountered considerable reticence on the part of interviewees when it came to revealing company-specific production problems or company-specific solutions. This was the case even though interviewees were assured that all responses would be held in confidence. Nevertheless, the following production issues were identified and ranked in order of decreasing importance: Water production including brine disposal; Management of production and business data; Oil field power costs; Paraffin accumulation; Production practices including cementing. An number of secondary issues were also noted: Problems associated with Enhanced Oil Recovery (EOR) and Waterflooding; Reservoir characterization; Employee availability, training, and safety; and Sale and Purchase problems. One item was mentioned both in interviews and in the Workshop, as, perhaps, the key issue related to oil production in the Appalachian region - the price of a barrel of oil. Project members sought solutions to production problems from a number of sources. In general, the Petroleum Technology Transfer Council (PTTC) website, both regional and national, proved to be a fertile source of information. Technical issues included water production, paraffin accumulation, production practices, EOR and waterflooding were addressed in a number of SPE papers. Articles on reservoir characterization were found in both the AAPG Bulletin and in SPE papers. Project members extracted topical and keyword information from pertinent articles and websites and combined them in a database that was placed on the PUMP website. Because of difficulties finding potential members with the qualifications, interests, and flexibility of schedule to allow a long-term commitment, it was decided to implement the PMP Regional Council as a subcommittee of the Producer Advisory Group (PAG) sponsored by Appalachian Region PTTC. The advantages of this decision are that the PAG is in already in existence as a volunteer group interested in problem identification and implementation of solutions and that PAG members are unpaid, so no outside funds will be required to sustain the group. The PUMP website became active in October of 2002. The site is designed to evolve; as new information becomes available, it can be readily added to the site or the site can be modified to accommodate it. The site is interactive allowing users to search within the PUMP site, within the Appalachian Region PTTC site, or within the whole internet through the input of user-supplied key words for information on oil production problems and solutions. Since its inception in the Fall of 2002, the PUMP site has experienced a growing number of users of increasingly diverse nature and from an increasing geographic area. This indicates that the site is reaching its target audience in the Appalachian region and beyond. Following up on a commitment to technology transfer, a total of eight focused-technology workshops were sponsored by the Appalachian Region PTTC center at the request of the PUMP project. Five Welltender Operations and Safety seminars were held in Kentucky, West Virginia, Ohio, and Pennsylvania. A two-day Applied Reservoir Characterization seminar and a one-day course on Paraffin, Asphaltene, and Scale problems were held in Pennsylvania. A one-day workshop on Produced Water was held in OH. In addition to workshops and the PUMP website, the project also generated several topical reports available to the public through the website and through USDOE.« less

Improved Characterization and Modeling of Tight Oil Formations for CO 2 Enhanced Oil Recovery Potential and Storage Capacity Estimation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sorensen, James; Smith, Steven; Kurz, Bethany

Tight oil formations such as those in the Bakken petroleum system are known to hold hundreds of billions of barrels of oil in place; however, the primary recovery factor for these plays is typically less than 10%. Tight oil formations, including the Bakken Formation, therefore, may be attractive candidates for enhanced oil recovery (EOR) using CO 2. Multiphase fluid behavior and flow in fluid-rich shales can vary substantially depending on the size of pore throats, and properties such as fluid viscosity and density are much different in nanoscale pores than in macroscale pores. Thus it is critical to understand themore » nature and distribution of nano-, micro-, and macroscale pores and fracture networks. To address these issues, the Energy & Environmental Research Center (EERC) has been conducting a research program entitled “Improved Characterization and Modeling of Tight Oil Formations for CO 2 Enhanced Oil Recovery Potential and Storage Capacity Estimation.” The objectives of the project are 1) the use of advanced characterization methods to better understand and quantify the petrophysical and geomechanical factors that control CO 2 and oil mobility within tight oil formation samples, 2) the determination of CO 2 permeation and oil extraction rates in tight reservoir rocks and organic-rich shales of the Bakken, and 3) the integration of the laboratory-based CO 2 permeation and oil extraction data and the characterization data into geologic models and dynamic simulations to develop predictions of CO 2 storage resource and EOR in the Bakken tight oil formation. A combination of standard and advanced petrophysical characterization techniques were applied to characterize samples of Bakken Formation tight reservoir rock and shales from multiple wells. Techniques included advanced computer tomography (CT) imaging, scanning electron microscopy (SEM) techniques, whole-core and micro x-ray CT imaging, field emission (FE) SEM, and focused ion beam (FIB) SEM. Selected samples were also analyzed for geomechanical properties. X-ray CT imaging yielded information on the occurrence of fractures, bedding planes, fossils, and bioturbation in core, as well as data on bulk density and photoelectric factor logs, which were used to interpret porosity, organic content, and mineralogy. FESEM was used for characterization of nano- and microscale features, including nanoscale pore visualization and micropore and pore throat mineralogy. FIBSEM yielded micro- to nanoscale visualization of fracture networks, porosity and pore-size distribution, connected versus isolated porosity, and distribution of organics. Results from the characterization activities provide insight on nanoscale fracture properties, pore throat mineralogy and connectivity, rock matrix characteristics, mineralogy, and organic content. Laboratory experiments demonstrated that CO 2 can permeate the tight matrix of Bakken shale and nonshale reservoir samples and mobilize oil from those samples. Geologic models were created at scales ranging from the core plug to the reservoir, and dynamic simulations were conducted. The data from the characterization and laboratory-based activities were integrated into modeling research activities to determine the fundamental mechanisms controlling fluid transport in the Bakken, which support EOR scheme design and estimation of CO 2 storage potential in tight oil formations. Simulation results suggest a CO 2 storage resource estimate range of 169 million to 1.5 billion tonnes for the Bakken in North Dakota, possibly resulting in 1.8 billion to 16 billion barrels of incremental oil.« less

PREDICTION OF THE SOLUBILITY OF HYDROPHOBIC COMPOUNDS IN NONIDEAL SOLVENT MIXTURES

EPA Science Inventory

The solubility of hydrophobic organic chemicals (HOCs) in partially-miscible solvent mixtures was investigated. In agreement with previous findings, it was observed that there is a limited domain in which nonideality effects are important; appreciable concentrations of partially-...

SORPTION KINETICS OF PAHS IN METHANOL-WATER SYSTEMS

EPA Science Inventory

The objectives of this study were to evaluate the relationships between the equilibrium sorption constant (Kp), the first-order desorption rate coefficient (k2), and the volumetric fraction of water miscible solvent (fc); and to utilize SPARC-calculated (SPARC Performs Automatic ...

Validated Test Method 5030C: Purge-and-Trap for Aqueous Samples

EPA Pesticide Factsheets

This method describes a purge-and-trap procedure for the analysis of volatile organic compoundsin aqueous samples & water miscible liquid samples. It also describes the analysis of high concentration soil and waste sample extracts prepared in Method 5035.

The "ouzo effect", recent developments and application to therapeutic drug carrying

NASA Astrophysics Data System (ADS)

Botet, Robert

2012-03-01

This short review is about the spontaneous emulsification effect, aka the "ouzo effect". Under certain conditions, pouring a mixture ol a totally water-miscible solvent and a hydrophobic oil into water, generates spontaneously nanometric droplets which are stable, even without surfactant. A basic example is anise-flavored aperitif, which is known from ages in South Europe and North Africa. Then, it is an amazingly old topic, potentially important in a number of applications - such as food additives, paints, cosmetic products or pharmaceutic drugs -, though the main mechanisms are yet essentially unexplained. This phenomenon is presently under intensive investigation using both microfluidic experiments and large-scale numerical simulations, through a CNRS project grouping four laboratories in France. This presentation will give an overview of the history, context and development of the ouzo effect, as well as recent advancements and ideas in the field. This unique effect is now related to two major streams of the scientific research, namely: nano-technology and bio-technology. Consequences in the latter domain is outlined.

SORPTION OF VINCLOZOLIN AND ATRAZINE ON FOUR GEOSORBENTS

EPA Science Inventory

The objectives of this study were to evaluate the magnitude and kinetics of vinclozolin and atrazine sorption on one surface soil and three freshwater sediments using batch and column techniques. Data from miscible displacement column studies were analyzed using a two-domain, fir...

COSOLVENT EFFECTS ON SORPTION AND MOBILITY OF ORGANIC CONTAMINANTS IN SOILS

EPA Science Inventory

Batch equilibrium and column miscible displacement techniques were used to investigate the influence of an organic cosolvent (methanol) on the sorption and transport of three hydrophobic organic chemicals (HOCs) — naphthalene, phenanthrene, and diuron herbicide — in a sandy surfa...

Can we treat CO₂ well blowouts like routine plumbing problems? A study of the incidence, impact, and perception of loss of well control

DOE PAGES

Porse, Sean L.; Wade, Sarah; Hovorka, Susan D.

2014-12-31

Risk communication literature suggests that for a number of reasons, the public may perceive a risk to be greater than indicated by its statistical probability. Public concern over risk can lead to significant and costly delays in project permitting and operations. Considering these theories, media coverage of CO₂-related well blowouts in 2013 gave rise to the questions: What is the risk of CO₂ well blowouts associated with CCUS through CO₂ EOR? What is the potential public perception of those risks? What information could be used to respond to public concern? To address these questions, this study aims to: 1) providemore » a framework for understanding the nature of onshore well blowouts, 2) quantify the incidence of such events for three specific geographic regions of Texas, 3) relate this data to CCUS and findings from other studies, and 4) explore the potential implications for public perception of this risk associated with CCUS projects. While quantifying answers to these questions proved to be challenging, the results from this study suggest that (1) the perceived risk of CO₂ well blowouts may exceed the statistical risk and (2) information that could be used to address this gap could be made more readily available to the greater benefit of industry and stakeholders who support the development of CCUS as an option for addressing anthropogenic CO₂ emissions. The study also suggests approaches to best conduct such data inquiries.« less

Formulation of 3D Printed Tablet for Rapid Drug Release by Fused Deposition Modeling: Screening Polymers for Drug Release, Drug-Polymer Miscibility and Printability.

PubMed

Solanki, Nayan G; Tahsin, Md; Shah, Ankita V; Serajuddin, Abu T M

2018-01-01

The primary aim of this study was to identify pharmaceutically acceptable amorphous polymers for producing 3D printed tablets of a model drug, haloperidol, for rapid release by fused deposition modeling. Filaments for 3D printing were prepared by hot melt extrusion at 150°C with 10% and 20% w/w of haloperidol using Kollidon ® VA64, Kollicoat ® IR, Affinsiol ™ 15 cP, and HPMCAS either individually or as binary blends (Kollidon ® VA64 + Affinisol ™ 15 cP, 1:1; Kollidon ® VA64 + HPMCAS, 1:1). Dissolution of crushed extrudates was studied at pH 2 and 6.8, and formulations demonstrating rapid dissolution rates were then analyzed for drug-polymer, polymer-polymer and drug-polymer-polymer miscibility by film casting. Polymer-polymer (1:1) and drug-polymer-polymer (1:5:5 and 2:5:5) mixtures were found to be miscible. Tablets with 100% and 60% infill were printed using MakerBot printer at 210°C, and dissolution tests of tablets were conducted at pH 2 and 6.8. Extruded filaments of Kollidon ® VA64-Affinisol ™ 15 cP mixtures were flexible and had optimum mechanical strength for 3D printing. Tablets containing 10% drug with 60% and 100% infill showed complete drug release at pH 2 in 45 and 120 min, respectively. Relatively high dissolution rates were also observed at pH 6.8. The 1:1-mixture of Kollidon ® VA64 and Affinisol ™ 15 cP was thus identified as a suitable polymer system for 3D printing and rapid drug release. Copyright © 2018 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Stability of viscosity stratified flows down an incline: Role of miscibility and wall slip

NASA Astrophysics Data System (ADS)

Ghosh, Sukhendu; Usha, R.

2016-10-01

The effects of wall velocity slip on the linear stability of a gravity-driven miscible two-fluid flow down an incline are examined. The fluids have the matched density but different viscosity. A smooth viscosity stratification is achieved due to the presence of a thin mixed layer between the fluids. The results show that the presence of slip exhibits a promise for stabilizing the miscible flow system by raising the critical Reynolds number at the onset and decreasing the bandwidth of unstable wave numbers beyond the threshold of the dominant instability. This is different from its role in the case of a single fluid down a slippery substrate where slip destabilizes the flow system at the onset. Though the stability properties are analogous to the same flow system down a rigid substrate, slip is shown to delay the surface mode instability for any viscosity contrast. It has a damping/promoting effect on the overlap modes (which exist due to the overlap of critical layer of dominant disturbance with the mixed layer) when the mixed layer is away/close from/to the slippery inclined wall. The trend of slip effect is influenced by the location of the mixed layer, the location of more viscous fluid, and the mass diffusivity of the two fluids. The stabilizing characteristics of slip can be favourably used to suppress the non-linear breakdown which may happen due to the coexistence of the unstable modes in a flow over a substrate with no slip. The results of the present study suggest that it is desirable to design a slippery surface with appropriate slip sensitivity in order to meet a particular need for a specific application.

Compatibility Studies Of Blends Of PPG 4000 And PEG 4000 Using Viscosity Technique

NASA Astrophysics Data System (ADS)

Venkatramanan, K.; Arumugam, V.

2010-06-01

Certain properties of polymers can be enhanced by mixing it with another polymer. When two or more polymers are intimately mixed in a single continuous solid product, the composition is generally referred to as a polymer blend or polyblend. Depending upon the degree of miscibility or immiscibility, such a polyblend may resemble a random copolymer or a block or graft copolymer or it may show micro or macro heterogeneous separation into a multiphase system. Viscosity method is simple and it offers very useful information about the relationship between dilute solution properties and bulk structure of the polymer blend. The basic idea of using viscosity as a parameter for compatibility determination of polymer blends lies in the fact that in solution the repulsive interaction may cause shrinkage of polymer coils resulting in a viscosity of the polymer mixture that is lower than the value calculated from viscosities of the pure components on the assumption of the additive law. In the present study, an attempt has been made to blend PPG 4000 with PEG 4000 in 1,4 -Dioxane at 303K at 1% concentration. The blend compositions were formed in the ratio 0:1, 0.2:0.8, 0.4:0.6, 0.5:0.5, 0.6:0.4, 0.8:0.2, 1:0. Relative viscosity of the blend compositions was determined and the values are nonlinear which showed incompatibility. Miscibility nature of the blends were determined further using additive law, log additive law and free volume additive law and the experimental values in all the cases showed negative deviation which is a characteristic of immiscible blend. The miscibility nature of the blend was further confirmed through density, ultrasonic velocity, refractive index and other techniques. The blend showed immiscibility.

The influence of guaifenesin and ketoprofen on the properties of hot-melt extruded polyethylene oxide films.

PubMed

Crowley, Michael M; Fredersdorf, Anke; Schroeder, Britta; Kucera, Shawn; Prodduturi, Suneela; Repka, Michael A; McGinity, James W

2004-08-01

Films containing polyethylene oxide (PEO) and a model drug, either guaifenesin (GFN) or ketoprofen (KTP), were prepared by hot-melt extrusion. The thermal properties of the hot-melt extruded films were investigated using differential scanning calorimetry (DSC). Scanning electron microscopy (SEM) was used to examine the surface morphology of the films, and wide angle X-ray diffraction (XRD) was used to investigate the crystalline properties of the polymer, drugs and physical mixtures as well as the solid state structure of the films. The stability of the polymer was studied using gel permeation chromatography. The mechanical properties, including percent elongation and tensile strength of the films, were determined on an Instron according to American Society for Testing Materials (ASTM) procedures. The Hansen solubility parameter was calculated using the Hoftyzer or van Krevelen method to estimate the likelihood of drug--polymer miscibility. Both GFN and KTP were stable during the extrusion process. Melting points corresponding to the crystalline drugs were not observed in the films. Crystallization of GFN on the surface of the film was observed at all concentrations studied, however KTP crystallization did not occur until reaching the 15% level. Guaifenesin and ketoprofen were found to decrease drive load, increase PEO stability and plasticize the polymer during extrusion. The Hansen solubility parameters predicted miscibility between PEO and KTP and poor miscibility between PEO and GFN. The predictions of the solubility parameters were in agreement with the XRD and SEM results. The percent elongation decreased with increasing GFN concentrations and significantly increased with increasing levels of KTP. Both GFN and KTP decreased the tensile strength of the extruded film.

Effect of gamma ray on poly(lactic acid)/poly(vinyl acetate-co-vinyl alcohol) blends as biodegradable food packaging films

NASA Astrophysics Data System (ADS)

Razavi, Seyed Mohammad; Dadbin, Susan; Frounchi, Masoud

2014-03-01

Poly(lactic acid) (PLA)/poly(vinyl acetate-co-vinyl alcohol) [P(VAc-co-VA)] blends as new transparent film packaging materials were prepared at various blend compositions and different vinyl alcohol contents. The blends and pure PLA were irradiated by gamma rays to investigate the extent of changes in the packaging material during gamma ray sterilization process. The miscibility of the blends was dependent on the blend composition and vinyl alcohol content; gamma irradiation had little effect on the extent of miscibility. The glass transition temperature of pure PLA and PLA/P(VAc-co-VA) miscible blends reduced after irradiation. On the other hand in PLA/P(VAc-co-VA) immiscible blends, while the glass transition temperature of the PLA phase decreased; that of the copolymer phase slightly increased. The reduction in the glass transition was about 10 percent for samples irradiated with 50 kGy indicating dominance of chain scission of PLA molecules at high irradiation dose. The latter was verified by drop in mechanical properties of pure PLA after exposing to gamma irradiation at 50 kGy. Blending of PLA with the copolymer P(VAc-co-VA) compensated greatly the adverse effects of irradiation on PLA. The oxygen-barrier property of the blend was superior to the neat PLA and remained almost intact with irradiation. The un-irradiated and irradiated blends had excellent transparency. Gamma ray doses used for sterilization purposes are usually less than 20 kGy. It was shown that gamma irradiation at 20 kGy had no or little adverse effects on PLA/P(VAc-co-VA) blends mechanical and gas barrier properties.

Increased physical stability and improved dissolution properties of itraconazole, a class II drug, by solid dispersions that combine fast- and slow-dissolving polymers.

PubMed

Six, Karel; Verreck, Geert; Peeters, Jef; Brewster, Marcus; Van Den Mooter, Guy

2004-01-01

Solid dispersions were prepared of itraconazole-Eudragit E100, itraconazole-PVPVA64, and itraconazole-Eudragit E100/PVPVA64 using a corotating twin-screw hot-stage extruder. Modulated temperature differential scanning calorimetry (MTDSC) was used to evaluate the miscibility of the extrudates, and dissolution experiments were performed in simulated gastric fluid without pepsin (SGF(sp)). Itraconazole and Eudragit E100 are miscible up to 13% w/w drug loading. From that concentration on, phase separation is observed. Pharmaceutical performance of this dispersion was satisfactory because 80% of the drug dissolved after 30 min. Extrudates of itraconazole and PVPVA64 were completely miscible but the pharmaceutical performance was low, with 45% of drug dissolved after 3 h. Combination of both polymers in different ratios, with a fixed drug loading of 40% w/w, was evaluated. MTDSC results clearly indicated a two-phase system consisting of itraconazole-Eudragit E100 and itraconazole-PVPVA64 phases. In these extrudates, no free crystalline or glassy clusters of itraconazole were observed; all itraconazole was mixed with one of both polymers. The pharmaceutical performance was tested in SGF(sp) for different polymer ratios, and Eudragit E100/PVPVA64 ratios of 50/50 and 60/40 showed significant increases in dissolution rate and level. Polymer ratios of 70/30 and 80/20, on the other hand, had a release of 85% after 30 min. Precipitation of the drug was never observed. The combination of the two polymers provides a solid dispersion with good dissolution properties and improved physical stability compared with the binary solid dispersions of itraconazole. Copyright 2004 Wiley-Liss, Inc.

Continuous melt granulation: Influence of process and formulation parameters upon granule and tablet properties.

PubMed

Monteyne, Tinne; Vancoillie, Jochem; Remon, Jean-Paul; Vervaet, Chris; De Beer, Thomas

2016-10-01

The pharmaceutical industry has a growing interest in alternative manufacturing models allowing automation and continuous production in order to improve process efficiency and reduce costs. Implementing a switch from batch to continuous processing requires fundamental process understanding and the implementation of quality-by-design (QbD) principles. The aim of this study was to examine the relationship between formulation-parameters (type binder, binder concentration, drug-binder miscibility), process-parameters (screw speed, powder feed rate and granulation temperature), granule properties (size, size distribution, shape, friability, true density, flowability) and tablet properties (tensile strength, friability, dissolution rate) of four different drug-binder formulations using Design of experiments (DOE). Two binders (polyethylene glycol (PEG) and Soluplus®) with a different solid state, semi-crystalline vs amorphous respectively, were combined with two model-drugs, metoprolol tartrate (MPT) and caffeine anhydrous (CAF), both having a contrasting miscibility with the binders. This research revealed that the granule properties of miscible drug-binder systems depended on the powder feed rate and barrel filling degree of the granulator whereas the granule properties of immiscible systems were mainly influenced by binder concentration. Using an amorphous binder, the tablet tensile strength depended on the granule size. In contrast, granule friability was more important for tablet quality using a brittle binder. However, this was not the case for caffeine-containing blends, since these phenomena were dominated by the enhanced compression properties of caffeine Form I, which was formed during granulation. Hence, it is important to gain knowledge about formulation behavior during processing since this influences the effect of process parameters onto the granule and tablet properties. Copyright © 2016 Elsevier B.V. All rights reserved.