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Sample records for miscible flood processes

  1. Scale-up of miscible flood processes

    SciTech Connect

    Orr, F.M. Jr.

    1992-05-01

    Results of a wide-ranging investigation of the scaling of the physical mechanisms of miscible floods are reported. Advanced techniques for analysis of crude oils are considered in Chapter 2. Application of supercritical fluid chromatography is demonstrated for characterization of crude oils for equation-of-state calculations of phase equilibrium. Results of measurements of crude oil and phase compositions by gas chromatography and mass spectrometry are also reported. The theory of development of miscibility is considered in detail in Chapter 3. The theory is extended to four components, and sample solutions for a variety of gas injection systems are presented. The analytical theory shows that miscibility can develop even though standard tie-line extension criteria developed for ternary systems are not satisfied. In addition, the theory includes the first analytical solutions for condensing/vaporizing gas drives. In Chapter 4, methods for simulation of viscous fingering are considered. The scaling of the growth of transition zones in linear viscous fingering is considered. In addition, extension of the models developed previously to three dimensions is described, as is the inclusion of effects of equilibrium phase behavior. In Chapter 5, the combined effects of capillary and gravity-driven crossflow are considered. The experimental results presented show that very high recovery can be achieved by gravity segregation when interfacial tensions are moderately low. We argue that such crossflow mechanisms are important in multicontact miscible floods in heterogeneous reservoirs. In addition, results of flow visualization experiments are presented that illustrate the interplay of crossflow driven by gravity with that driven by viscous forces.

  2. Scale-up of miscible flood processes. Annual report

    SciTech Connect

    Orr, F.M. Jr.

    1992-05-01

    Results of a wide-ranging investigation of the scaling of the physical mechanisms of miscible floods are reported. Advanced techniques for analysis of crude oils are considered in Chapter 2. Application of supercritical fluid chromatography is demonstrated for characterization of crude oils for equation-of-state calculations of phase equilibrium. Results of measurements of crude oil and phase compositions by gas chromatography and mass spectrometry are also reported. The theory of development of miscibility is considered in detail in Chapter 3. The theory is extended to four components, and sample solutions for a variety of gas injection systems are presented. The analytical theory shows that miscibility can develop even though standard tie-line extension criteria developed for ternary systems are not satisfied. In addition, the theory includes the first analytical solutions for condensing/vaporizing gas drives. In Chapter 4, methods for simulation of viscous fingering are considered. The scaling of the growth of transition zones in linear viscous fingering is considered. In addition, extension of the models developed previously to three dimensions is described, as is the inclusion of effects of equilibrium phase behavior. In Chapter 5, the combined effects of capillary and gravity-driven crossflow are considered. The experimental results presented show that very high recovery can be achieved by gravity segregation when interfacial tensions are moderately low. We argue that such crossflow mechanisms are important in multicontact miscible floods in heterogeneous reservoirs. In addition, results of flow visualization experiments are presented that illustrate the interplay of crossflow driven by gravity with that driven by viscous forces.

  3. Scale-up of miscible flood processes for heterogeneous reservoirs. Quarterly report, April 1, 1994--June 30, 1994

    SciTech Connect

    Orr, F.M. Jr.

    1994-07-01

    The current project is a systematic research effort to quantify relationships between process mechanisms that can lead to improved recovery from gas injection processes performed in heterogeneous Class 1 and Class 2 reservoirs. It will provide a rational basis for the design of displacement processes that take advantage of crossflow due to capillary, gravity and viscous forces to offset partially the adverse effects of heterogeneity. In effect, the high permeability zones are used to deliver fluid by crossflow to zones that would otherwise be flooded only very slowly. Thus, the research effort is divided into five areas: (a) Development of miscibility in multicomponent systems, (b) Design estimates for nearly miscible displacements, (c) Design of miscible floods for fractured reservoirs (d), Compositional flow visualization experiments, and (e) Simulation of near-miscible flow in heterogeneous systems. The status of the research effort in each area is reviewed briefly in the following section.

  4. Scale-up of miscible flood processes. [Quarterly report], January 1--April 31, 1992

    SciTech Connect

    Orr, F.M. Jr.

    1992-08-01

    Efficient application of miscible floods to heterogeneous reservoirs requires the designer to take advantage of more than one of the physical mechanisms that act and interact to determine displacement performance. In this report, the investigators summarize the interactions of phase behavior, nonuniform flow, and crossflow and based on novel results obtained during the course of their experimental efforts. They suggest design opportunities for application of gas injection to near-miscible recovery processes, to enhanced gravity drainage, and even to fractured reservoirs. To design such processes intelligently, the quantitative scaling of the interplay of phase equilibria, reservoir heterogeneity, viscous fingering and particularly crossflow must be understood. In essence, they propose to make use of crossflow, i.e. transport in the direction transverse to the basic flow direction, to sweep portions of reservoirs that can be reached only very slowly by direct displacement. In this report, the core displacement and flow visualization experiments described suggest that the effects of low interfacial tensions (IFT`s) and gravity can be used to advantage in the design of multicontact miscible displacements for heterogeneous reservoirs, including fractured reservoirs.

  5. Scale-up of miscible flood processes for heterogeneous reservoirs. Final report

    SciTech Connect

    Orr, F.M. Jr.

    1996-04-01

    Results of a wide-ranging investigation of the scaling of gas injection processes are reported. The research examines how the physical mechanisms at work during a gas injection project interact to determine process performance. In particular, the authors examine: the interactions of equilibrium phase behavior and two-phase flow that determine local displacement efficiency and minimum miscibility pressure, the combined effects of viscous fingering, gravity segregation and heterogeneity that control sweep efficiency in 2- and 3-dimensional porous media, the use of streamtube/streamline methods to create very efficient simulation technique for multiphase compositional displacements, the scaling of viscous, capillary and gravity forces for heterogeneous reservoirs, and the effects of the thin films and spreading behavior on three-phase flow. The following key results are documented: rigorous procedures for determination of minimum miscibility pressure (MMP) or minimum miscibility enrichment (MME) for miscibility have been developed for multicomponent systems; the complex dependence of MMP`s for nitrogen/methane floods on oil and injection gas composition observed experimentally is explained for the first time; the presence of layer-like heterogeneities strongly influences the interplay of gravity segregation and viscous fingering, as viscous fingers adapt to preferential flow paths and low permeability layers restrict vertical flow; streamtube/streamline simulation techniques are demonstrated for a variety of injection processes in 2 and 3 dimensions; quantitative scaling estimates for the transitions from capillary-dominated to gravity-dominated to viscous-dominated flows are reported; experimental results are given that demonstrate that high pressure CO{sub 2} can be used to generate low IFT gravity drainage in fractured reservoirs if fractures are suitably connected; and the effect of wetting and spreading behavior on three-phase flow is described. 209 refs.

  6. Scale-up of miscible flood processes. Quarterly report, July 1, 1993--September 30, 1993

    SciTech Connect

    Orr, F.M. Jr.

    1993-12-31

    Progress is reported for a comprehensive investigation of the scaling behavior of gas injection processes in heterogeneous reservoirs. The interplay of phase behavior, viscous fingering, gravity segregation, capillary imbibition and drainage, and reservoir heterogeneity is examined in a series of simulations and experiments. Compositional and first-contact miscible simulations of viscous fingering and gravity segregation are compared to show that the two techniques can give very different results. Also, analyzed are two-dimensional and three-dimensional flows in which gravity segregation and viscous fingering interact. The simulations show that 2D and 3D flows can differ significantly. A comparison of analytical solutions for three-component two-phase flow with experimental results for oil/water/alcohol systems is reported. While the experiments and theory show reasonable agreement, some differences remain to be explained. The scaling behavior of the interaction of gravity segregation and capillary forces is investigated through simulations and through scaling arguments based on analysis of the differential equations. The simulations show that standard approaches do not agree well with results of low IFT displacements. The scaling analyses, however, reveal flow regimes where capillary, gravity, or viscous forces dominate the flow.

  7. Scale-up of miscible flood processes for heterogeneous reservoirs. Second annual report

    SciTech Connect

    Orr, F.M. Jr.

    1995-03-01

    Progress is reported for a comprehensive investigation of the scaling behavior of gas injection processes in heterogeneous reservoirs. The interplay of phase behavior, viscous fingering, gravity segregation, capillary imbibition and drainage, and reservoir heterogeneity is examined in a series of simulations and experiments. Use of streamtube to model multiphase flow is demonstrated to be a fast and accurate approach for displacements that are dominated by reservoir heterogeneity. The streamtube technique is particularly powerful for multiphase compositional displacements because it represents the effects of phase behavior with a one-dimensional flow and represents the effects of heterogeneity through the locations of streamtubes. A new approach for fast calculations of critical tie-lines directly from criticality conditions is reported. A global triangular structure solution for four-component flow systems, whose tie-lies meet at the edge of a quaternary phase diagram or lie in planes is presented. Also demonstrated is the extension of this solution to multicomponent systems under the same assumptions. The interplay of gravity, capillary and viscous forces on final residual oil saturation is examined experimentally and theoretically. The analysis of vertical equilibrium conditions for three-phase gravity drainage shows that almost all oil can be recovered from the top part of a reservoir. The prediction of spreading and stability of thin film is performed to investigate three-phase gravity drainage mechanisms. Finally, experimental results from gravity drainage of crude oil in the presence of CO{sub 2} suggest that gravity drainage could be an efficient oil recovery process for vertically fractured reservoirs.

  8. Scale-up of miscible flood processes for heterogeneous reservoirs. 1993 annual report

    SciTech Connect

    Orr, F.M. Jr.

    1994-05-01

    Progress is reported for a comprehensive investigation of the scaling behavior of gas injection processes in heterogeneous reservoirs. The interplay of phase behavior, viscous fingering, gravity segregation, capillary imbibition and drainage, and reservoir heterogeneity is examined in a series of simulations and experiments. Compositional and first-contact miscable simulations of viscous fingering and gravity segregation are compared to show that the two techniques can give very different results. Also, analyzed are two-dimensional and three-dimensional flows in which gravity segregation and viscous fingering interact. The simulations show that 2D and 3D flows can differ significantly. A comparison of analytical solutions for three-component two-phase flow with experimental results for oil/water/alcohol systems is reported. While the experiments and theory show reasonable agreement, some differences remain to be explained. The scaling behavior of the interaction of gravity segregation and capillary forces is investigated through simulations and through scaling arguments based on analysis of the differential equations. The simulations show that standard approaches do not agree well with results of low IFT displacements. The scaling analyses, however, reveal flow regimes where capillary, gravity, or viscous forces dominate the flow.

  9. Improved Efficiency of Miscible CO2 Floods and Enhanced Prospects for CO2 Flooding Heterogeneous Reservoirs

    SciTech Connect

    Grigg, Reid B.; Schechter, David S.

    1999-10-15

    The goal of this project is to improve the efficiency of miscible CO2 floods and enhance the prospects for flooding heterogeneous reservoirs. This report provides results of the second year of the three-year project that will be exploring three principles: (1) Fluid and matrix interactions (understanding the problems). (2) Conformance control/sweep efficiency (solving the problems. 3) Reservoir simulation for improved oil recovery (predicting results).

  10. Potential Mississippi oil recovery and economic impact from CO sub 2 miscible flooding

    SciTech Connect

    Moring, J.A.; Rogers, R.E. )

    1991-01-01

    Maturing of Mississippi oil reservoirs has resulted in a steady decline in crude oil production in the state. This paper reports that, to evaluate the potential of enhanced recovery processes, particularly in the use of the state's large CO{sub 2} reserves, for arresting this trend, the subject study was performed. A computer data base of over 1315 Mississippi reservoirs was established. All reservoirs were screened for applicability of the carbon dioxide miscible process. With models developed by the National Petroleum Council and DOE, incremental oil that could be produced from the carbon dioxide miscible process was calculated. Under selected economic conditions, carbon dioxide miscible flooding with utilization of carbon dioxide from the state's Norphlet formation (3-7 tcf reserves of high-purity CO{sub 2}) could produce 120 million barrels of incremental oil in Mississippi. Incremental state revenues as a consequence of this production were calculated to be $45 million of severance taxes, $50 million of corporate income taxes, and $60 million of royalty payments, expressed as present values.

  11. The tertiary extension of the Wizard Lake D-3A pool miscible flood

    SciTech Connect

    Backmeyer, L.A.; Guise, D.R.; Mac Donell, P.E.; Nute, A.J.

    1984-09-01

    A tertiary extension of the existing secondary hydrocarbon miscible flood in the Wizard Lake D-3A Pool was implemented in October, 1983. The extension will result in the oil-water contact being lowered 22.6 meters (74.1 feet) to allow miscible displacement of the residual oil in the water flushed portion of the reef. This water flushed zone was formed when the oil-water contact rose during primary depletion of the reservoir from discovery in 1951 until the implementation of the secondary miscible flood in 1969, and also during the repressuring phase of the secondary miscible flood. Ultimate recovery from the pool is expected to be 59 539 10/sup 3/m/sup 3/ (374.49 MMSTB) or 95.95 percent of the original oil-in-place; which is 4 531 10/sup 3/m/sup 3/ (28.50 MMSTB) higher than the secondary miscible flood and 18 583 10/sup 3/m/sup 3/ (116.88 MMSTB) more than under primary depletion. This paper reviews the implementation and monitoring of the tertiary extension of the miscible flood and also the performance of the pool to January 1, 1984.

  12. Origin of Scale-Dependent Dispersivity and Its Implications For Miscible Gas Flooding

    SciTech Connect

    Steven Bryant; Russ Johns; Larry Lake; Thomas Harmon

    2008-09-30

    Dispersive mixing has an important impact on the effectiveness of miscible floods. Simulations routinely assume Fickian dispersion, yet it is well established that dispersivity depends on the scale of measurement. This is one of the main reasons that a satisfactory method for design of field-scale miscible displacement processes is still not available. The main objective of this project was to improve the understanding of the fundamental mechanisms of dispersion and mixing, particularly at the pore scale. To this end, microsensors were developed and used in the laboratory to measure directly the solute concentrations at the scale of individual pores; the origin of hydrodynamic dispersion was evaluated from first principles of laminar flow and diffusion at the grain scale in simple but geometrically completely defined porous media; techniques to use flow reversal to distinguish the contribution to dispersion of convective spreading from that of true mixing; and the field scale impact of permeability heterogeneity on hydrodynamic dispersion was evaluated numerically. This project solved a long-standing problem in solute transport in porous media by quantifying the physical basis for the scaling of dispersion coefficient with the 1.2 power of flow velocity. The researchers also demonstrated that flow reversal uniquely enables a crucial separation of irreversible and reversible contributions to mixing. The interpretation of laboratory and field experiments that include flow reversal provides important insight. Other advances include the miniaturization of long-lasting microprobes for in-situ, pore-scale measurement of tracers, and a scheme to account properly in a reservoir simulator (grid-block scale) for the contributions of convective spreading due to reservoir heterogeneity and of mixing.

  13. Improved efficiency of miscible CO{sub 2} floods and enhanced prospects for CO{sub 2} flooding heterogeneous reservoirs. Annual report, April 14, 1994--April 13, 1995

    SciTech Connect

    Grigg, R.; Heller, J.; Schechter, D.

    1995-09-01

    The overall goal of this project is to improve the efficiency of miscible CO{sub 2} floods and enhance the prospects for flooding heterogeneous reservoirs. This objective is being accomplished by extending experimental research in three task areas: (1) foams for selective mobility control in heterogeneous reservoirs, (2) reduction of the amount of CO{sub 2} required in CO{sub 2} floods, and (3) miscible CO{sub 2} flooding in fractured reservoirs. This report provides results of the first year of the three-year project for each of the three task areas.

  14. FIELD DEMONSTRATION OF CARBON DIOXIDE MISCIBLE FLOODING IN THE LANSING-KANSAS CITY FORMATION, CENTRAL KANSAS

    SciTech Connect

    Alan Byrnes; G. Paul Willhite; Don Green; Martin Dubois; Richard Pancake; Timothy Carr; W. Lynn Watney; John Doveton; Willard Guy; Rodney Reynolds; Dave Murfin; James Daniels; Russell Martin; William Flanders; Dave Vander Griend; Eric Mork; Paul Cantrell

    2004-06-30

    A pilot carbon dioxide miscible flood was initiated in the Lansing Kansas City C formation in the Hall Gurney Field, Russell County, Kansas. Continuous carbon dioxide injection began on December 2, 2003. By the end of June 2004, 6.26 MM lb of carbon dioxide were injected into the pilot area. Carbon dioxide injection rates averaged about 250 MCFD. Carbon dioxide was detected in one production well near the end of May. The amount of carbon dioxide produced was small during this period. Wells in the pilot area produced 100% water at the beginning of the flood. Oil production began in February, increasing to an average of about 2.5 B/D in May and June. Operational problems encountered during the initial stages of the flood were identified and resolved.

  15. Development of a method for evaluating carbon dioxide miscible flooding prospects. Final report

    SciTech Connect

    Green, D.W.; Swift, G.W.

    1985-03-01

    Research was undertaken to develop a method of evaluating reservoirs as prospects for carbon dioxide flooding. Evaluation was to be based on a determination of miscibility pressure and displacement efficiency under idealized conditions. To reach the objective, project work was divided into five areas: (1) conducting of phase-equilibrium studies of carbon dioxide with synthetic oils; (2) application of an equation of state to simulate the phase behavior of carbon dioxide - oil systems; (3) conducting of linear displacements of crude oils and synthetic oils by carbon dioxide in a slim-tube apparatus; (4) application of the equation of state, the phase-behavior data and slim-tube data to develop a method of screening reservoirs for carbon dioxide flooding based on determination of minimum miscibility pressure and displacement efficiency; (5) development of a one-dimensional mathematical model, based on the equation of state, for application in conjunction with the results of Parts 1 to 4. The accomplishments for these five areas are discussed in five chapters. 44 references, 90 figures, 42 tables.

  16. Improved minimum miscibility pressure correlation for CO2 flooding using various oil components and their effects

    NASA Astrophysics Data System (ADS)

    Lai, Fengpeng; Li, Zhiping; Hu, Xiaoqing

    2017-03-01

    Carbon dioxide (CO2) flooding is an effective method of enhanced oil recovery (EOR) that has become one of the most important EOR processes. One of the key factors in the design of a CO2 injection project is the minimum miscibility pressure (MMP), whereas local sweeping efficiency during gas injection is dependent on the MMP. There are many empirical correlation analyses for the MMP calculation. However, these analyses focus on the molecular weight of the C5+ or C7+ fraction, and do not emphasize the effects of various components on MMP. Our study aims to develop an improved CO2–oil MMP correlation analysis that includes parameters such as reservoir temperature and various oil mole fractions. Here, correlation analysis was performed to define the influence of various components on the MMP using various data from 45 oilfields which have experimental CO2–oil MMP and oil compositions readily available. Thirty of the data sets were used to develop an improved correlation, and the other 15 data sets were used to verify the correlation. It was found that the mole fraction of C3 and C6 were the main factors that affected MMP. There was a good quadratic polynomial relationship between the mole fraction of C3 and MMP, and the relationship also existed between the mole fraction of C6 and MMP. The results do not include the molecular weight of the C5+ or C7+ fraction like other common correlations. Nine popular correlations were then used to also predict the MMP, and the comparison showed that the improved CO2–oil MMP correlation defined here was a better estimate. The correlation was then used in Dongshisi and Fuyu oilfields to assess EOR potential, the results also indicated that MMP increased over the course of the CO2 flooding process. This increase shows that it would be more difficult to achieve a mixed phase between crude oil and CO2, therefore the oil recovery would be difficult to further improve towards the end of injection.

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

    SciTech Connect

    Bou-Mikael, Sami

    2002-02-05

    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.

  18. Field Demonstration of Carbon Dioxide Miscible Flooding in the Lansing-Kansas City Formation, Central Kansas

    SciTech Connect

    Alan Byrnes; G. Paul Willhite; Don Green; Richard Pancake; JyunSyung Tsau; W. Lynn Watney; John Doveton; Willard Guy; Rodney Reynolds; Dave Murfin; James Daniels; Russell Martin; William Flanders; Dave Vander Griend; Eric Mork; Paul Cantrell

    2010-03-07

    A pilot carbon dioxide miscible flood was initiated in the Lansing Kansas City C formation in the Hall Gurney Field, Russell County, Kansas. The reservoir zone is an oomoldic carbonate located at a depth of about 2900 feet. The pilot consists of one carbon dioxide injection well and three production wells. Continuous carbon dioxide injection began on December 2, 2003. By the end of June 2005, 16.19 MM lb of carbon dioxide was injected into the pilot area. Injection was converted to water on June 21, 2005 to reduce operating costs to a breakeven level with the expectation that sufficient carbon dioxide was injected to displace the oil bank to the production wells by water injection. By March 7,2010, 8,736 bbl of oil were produced from the pilot. Production from wells to the northwest of the pilot region indicates that oil displaced from carbon dioxide injection was produced from Colliver A7, Colliver A3, Colliver A14 and Graham A4 located on adjacent leases. About 19,166 bbl of incremental oil were estimated to have been produced from these wells as of March 7, 2010. There is evidence of a directional permeability trend toward the NW through the pilot region. The majority of the injected carbon dioxide remains in the pilot region, which has been maintained at a pressure at or above the minimum miscibility pressure. Estimated oil recovery attributed to the CO2 flood is 27,902 bbl which is equivalent to a gross CO2 utilization of 4.8 MCF/bbl. The pilot project is not economic.

  19. Development and verification of simplified prediction models for enhanced oil recovery applications. CO/sub 2/ (miscible flood) predictive model. Final report

    SciTech Connect

    Paul, G.W.

    1984-10-01

    A screening model for CO/sub 2/ miscible flooding has been developed consisting of a reservoir model for oil rate and recovery and an economic model. The reservoir model includes the effects of viscous fingering, reservoir heterogeneity, gravity segregation and areal sweep. The economic model includes methods to calculate various profitability indices, the windfall profits tax, and provides for CO/sub 2/ recycle. The model is applicable to secondary or tertiary floods, and to solvent slug or WAG processes. The model does not require detailed oil-CO/sub 2/ PVT data for execution, and is limited to five-spot patterns. A pattern schedule may be specified to allow economic calculations for an entire project to be made. Models of similar architecture have been developed for steam drive, in-situ combustion, surfactant-polymer flooding, polymer flooding and waterflooding. 36 references, 41 figures, 4 tables.

  20. A simulation research on evaluation of development in shale oil reservoirs by near-miscible CO2 flooding

    NASA Astrophysics Data System (ADS)

    Lai, Fengpeng; Li, Zhiping; Fu, Yingkun; Yang, Zhihao; Li, Hong

    2015-08-01

    Shale oil is a key resource that could mitigate the impending energy shortage in the future. Despite its abundance in China, studies on shale oil are still at the preliminary stage. Shale oil development through CO2 flooding has been successfully implemented in the United States. Therefore, the mechanics of CO2 flooding in shale oil reservoirs should be investigated. This study applies a simulation method to evaluate the development efficiency of CO2 flooding in shale oil reservoirs. Near-miscible CO2 flooding can effectively develop shale oil. After 20 years, recovery could improve by up to 9.56% as a result of depletion development under near-miscible CO2 flooding with 0.5% pore volume gas injection. Horizontal well injection is better than vertical well injection in terms of sweep efficiency and recovery. Cyclic gas injection is superior to continuous gas injection because the former reduces gas channelling. Thus, the use of horizontal wells with near-miscible cyclic gas injections has the potential to effectively develop shale oil reservoirs.

  1. 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 CO2-oil two-phase flow characteristic and displacement front behavior in porous media, for understanding the mechanisms of CO2 enhanced oil recovery. In this work, we carried out near miscible CO2 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 CO2 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.

  2. FIELD DEMONSTRATION OF CARBON DIOXIDE MISCIBLE FLOODING IN THE LANSING-KANSAS CITY FORMATION, CENTRAL KANSAS

    SciTech Connect

    Alan Byrnes; G. Paul Willhite; Don Green; Martin Dubois; Richard Pancake; Timothy Carr; W. Lynn Watney; John Doveton; Willard Guy; Rodney Reynolds; Dave Murfn; James Daniels; Russell Martin; William Flanders; Dave Vander Griend; Eric Mork; Paul Cantrell

    2004-12-31

    A pilot carbon dioxide miscible flood was initiated in the Lansing Kansas City C formation in the Hall Gurney Field, Russell County, Kansas. Continuous carbon dioxide injection began on December 2, 2003. By the end of December 2004, 11.39 MM lb of carbon dioxide were injected into the pilot area. Carbon dioxide injection rates averaged about 242 MCFD. Vent losses were excessive during June as ambient temperatures increased. Installation of smaller plungers in the carbon dioxide injection pump reduced the recycle and vent loss substantially. Carbon dioxide was detected in one production well near the end of May and in the second production well in August. No channeling of carbon dioxide was observed. The GOR has remained within the range of 3000-4000 for most the last six months. Wells in the pilot area produced 100% water at the beginning of the flood. Oil production began in February, increasing to an average of about 2.35 B/D for the six month period between July 1 and December 31. Cumulative oil production was 814 bbls. Neither well has experienced increased oil production rates expected from the arrival of the oil bank generated by carbon dioxide injection.

  3. Field Demonstration of Carbon Dioxide Miscible Flooding in the Lansing-Kansas City Formation, Central Kansas

    SciTech Connect

    Alan Byrnes; G. Paul Willhite; Don Green; Martin Dubois; Richard Pancake; Timothy Carr; W. Lynn Watney; John Doveton; Willard Guy; Rodney Reynolds; Dave Murfin; James Daniels; Russell Martin; William Flanders; Dave Vander Griend; Eric Mork; Paul Cantrell

    2007-03-07

    A pilot carbon dioxide miscible flood was initiated in the Lansing Kansas City C formation in the Hall Gurney Field, Russell County, Kansas. The reservoir zone is an oomoldic carbonate located at a depth of about 2900 feet. The pilot consists of one carbon dioxide injection well and three production wells. Continuous carbon dioxide injection began on December 2, 2003. By the end of June 2005, 16.19 MM lb of carbon dioxide were injected into the pilot area. Injection was converted to water on June 21, 2005 to reduce operating costs to a breakeven level with the expectation that sufficient carbon dioxide has been injected to displace the oil bank to the production wells by water injection. By December 31, 2006, 79,072 bbls of water were injected into CO2 I-1 and 3,923 bbl of oil were produced from the pilot. Water injection rates into CO2 I-1, CO2 No.10 and CO2 No.18 were stabilized during this period. Oil production rates increased from 4.7 B/D to 5.5 to 6 B/D confirming the arrival of an oil bank at CO2 No.12. Production from wells to the northwest of the pilot region indicates that oil displaced from carbon dioxide injection was produced from Colliver No.7, Colliver No.3 and possibly Graham A4 located on an adjacent property. There is evidence of a directional permeability trend toward the NW through the pilot region. The majority of the injected carbon dioxide remains in the pilot region, which has been maintained at a pressure at or above the minimum miscibility pressure. Our management plan is to continue water injection maintaining oil displacement by displacing the carbon dioxide remaining in the C zone,. If the decline rate of production from the Colliver Lease remains as estimated and the oil rate from the pilot region remains constant, we estimate that the oil production attributed to carbon dioxide injection will be about 12,000 bbl by December 31, 2007. Oil recovery would be equivalent to 12 MCF/bbl, which is consistent with field experience in

  4. FIELD DEMONSTRATION OF CARBON DIOXIDE MISCIBLE FLOODING IN THE LANSING-KANSAS CITY FORMATION, CENTRAL KANSAS

    SciTech Connect

    Alan Byrnes; G. Paul Willhite; Don Green; Martin Dubois; Richard Pancake; Timothy Carr; W. Lynn Watney; John Doveton; Willard Guy; Rodney Reynolds; Dave Murfin; James Daniels; Russell Martin; William Flanders; Dave Vander Griend; Eric Mork; Paul Cantrell

    2006-06-30

    A pilot carbon dioxide miscible flood was initiated in the Lansing Kansas City C formation in the Hall Gurney Field, Russell County, Kansas. The reservoir zone is an oomoldic carbonate located at a depth of about 2900 feet. The pilot consists of one carbon dioxide injection well and two production wells on about 10 acre spacing. Continuous carbon dioxide injection began on December 2, 2003. By the end of June 2005, 16.19 MM lb of carbon dioxide were injected into the pilot area. Injection was converted to water on June 21, 2005 to reduce operating costs to a breakeven level with the expectation that sufficient carbon dioxide has been injected to displace the oil bank to the production wells by water injection. Wells in the pilot area produced 100% water at the beginning of the flood. Oil production began in February 2004, increasing to an average of about 3.78 B/D for the six month period between January 1 and June 30, 2005 before declining. By June 30, 2006, 41,566 bbls of water were injected into CO2I-1 and 2,726 bbl of oil were produced from the pilot. Injection rates into CO2I-1 declined with time, dropping to an unacceptable level for the project. The injection pressure was increased to reach a stable water injection rate of 100 B/D. However, the injection rate continued to decline with time, suggesting that water was being injected into a region with limited leakoff and production. Oil production rates remained in the range of 3-3.5 B/D following conversion to water injection. Oil rates increased from about 3.3 B/D for the period from January through March to about 4.7 B/D for the period from April through June. If the oil rate is sustained, this may be the first indication of the arrival of the oil bank mobilized by carbon dioxide injection. A sustained fluid withdrawal rate of about 200 B/D from CO2 No.12 and CO2 No.13 appears to be necessary to obtain higher oil rates. There is no evidence that the oil bank generated by injection of carbon dioxide has

  5. FIELD DEMONSTRATION OF CARBON DIOXIDE MISCIBLE FLOODING IN THE LANSING-KANSAS CITY FORMATION, CENTRAL KANSAS

    SciTech Connect

    Alan Byrnes; G. Paul Willhite; Don Green; Martin Dubois; Richard Pancake; Timothy Carr; W. Lynn Watney; John Doveton; Willard Guy; Rodney Reynolds; Dave Murfin; James Daniels; Russell Martin; William Flanders; Dave Vander Griend; Eric Mork; Paul Cantrell

    2005-12-31

    A pilot carbon dioxide miscible flood was initiated in the Lansing Kansas City C formation in the Hall Gurney Field, Russell County, Kansas. The reservoir zone is an oomoldic carbonate located at a depth of about 2900 feet. The pilot consists of one carbon dioxide injection well and two production wells on about 10 acre spacing. Continuous carbon dioxide injection began on December 2, 2003. By the end of June 2005, 16.19 MM lb of carbon dioxide were injected into the pilot area. Injection was converted to water on June 21, 2005 to reduce operating costs to a breakeven level with the expectation that sufficient carbon dioxide has been injected to displace the oil bank to the production wells by water injection. Wells in the pilot area produced 100% water at the beginning of the flood. Oil production began in February 2004, increasing to an average of about 3.78 B/D for the six month period between January 1 and June 30, 2005 before declining. By the end of December 2005, 14,115 bbls of water were injected into CO2I-1 and 2,091 bbl of oil were produced from the pilot. Injection rates into CO2I-1 declined with time, dropping to an unacceptable level for the project. The injection pressure was increased to reach a stable water injection rate of 100 B/D. However, the injection rate continued to decline with time, suggesting that water was being injected into a region with limited leakoff and production. Oil production rates remained in the range of 3-3.5 B/D following conversion to water injection. There is no evidence that the oil bank generated by injection of carbon dioxide has reached either production well. Continued injection of water is planned to displace oil mobilized by carbon dioxide to the production wells and to maintain the pressure in the PPV region at a level that supports continued miscible displacement as the carbon dioxide is displaced by the injected water.

  6. Improved efficiency of miscible CO{sub 2} floods and enhanced prospects for CO{sub 2} flooding heterogeneous reservoirs. Annual report, April 18, 1995--April 17, 1996

    SciTech Connect

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

    1996-10-01

    The overall goal of this project is to improve the efficiency of miscible CO{sub 2} floods and enhance the prospects for flooding heterogeneous reservoirs. This objective is being accomplished by extending experimental and modeling research in three task areas: (1) foams for selective mobility control in heterogeneous reservoirs, (2) reduction of the amount of CO{sub 2} required in CO{sub 2} floods, and (3) low IFT processes and the possibility of CO{sub 2} flooding in fractured reservoirs. This report provides results of the second year of the three-year project for each of the three task areas. In the first task, we are investigating a desirable characteristic of CO{sub 2}-foam called Selective Mobility Reduction (SMR) that results in an improvement in displacement efficiency by reducing the effects of reservoir heterogeneity. Research on SMR of foam during the past year has focused on three subjects: (1) to verify SMR in different rock permeabilities that are in capillary contact; (2) to test additional surfactants for the SMR property; and (3) to develop a modeling approach to assess the oil recovery efficiency of SMR in CO{sub 2}-foam on a reservoir scale. The experimental results from the composite cores suggest that the rock heterogeneity has significant effect on two phase (CO{sub 2}/brine) flow behavior in porous media, and that foam can favorably control CO{sub 2} mobility. The numerical modeling results suggest that foam with SMR can substantially increase the sweep efficiency and therefore improve oil recovery.

  7. Improved Efficiency of Miscible CO2 Floods and Enhanced Prospects for CO2 Flooding Heterogeneous Reservoirs

    SciTech Connect

    Grigg, Reid B.

    1999-10-28

    Continued testing the horizontal-well capabilities of MASTER, the DOE's pseudomiscible reservoir simulator, by running simulation tests with several combinations of horizontal and vertical wells and various alternative reservoir descriptions. These sensitivity tests were compared and validated using simulation results from a commercial simulator. This sensitivity study was used in conjunction with our numerical tests on the comparison of foam injection processes and horizontal well injection processes. In addition, a preprocessor used to set up the input file to MASTER and a postprocessor for plotting the well performance were completed. Tests were progressed and the official version of MASTER will be released in the next few months.

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

    SciTech Connect

    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 database 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.

  9. Improved efficiency of miscible CO2 floods and enhanced prospects for CO2 flooding heterogeneous reservoirs. Final report, April 17, 1991--May 31, 1997

    SciTech Connect

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

    1998-02-01

    From 1986 to 1996, oil recovery in the US by gas injection increased almost threefold, to 300,000 bbl/day. Carbon dioxide (CO{sub 2}) injection projects make up three-quarters of the 191,139 bbl/day production increase. This document reports experimental and modeling research in three areas that is increasing the number of reservoirs in which CO{sub 2} can profitably enhance oil recovery: (1) foams for selective mobility reduction (SMR) in heterogeneous reservoirs, (2) reduction of the amount of CO{sub 2} required in CO{sub 2} floods, and (3) low interfacial tension (97) processes and the possibility of CO{sub 2} flooding in naturally fractured reservoirs. CO{sub 2} injection under miscible conditions can effectively displace oil, but due to differences in density and viscosity the mobility of CO{sub 2} is higher than either oil or water. High CO{sub 2} mobility causes injection gas to finger through a reservoir, causing such problems as early gas breakthrough, high gas production rates, excessive injection gas recycling, and bypassing of much of the reservoir oil. These adverse effects are exacerbated by increased reservoir heterogeneity, reaching an extreme in naturally fractured reservoirs. Thus, many highly heterogeneous reservoirs have not been considered for CO{sub 2} injection or have had disappointing recoveries. One example is the heterogeneous Spraberry trend in west Texas, where only 10% of its ten billion barrels of original oil in place (OOIP) are recoverable by conventional methods. CO{sub 2} mobility can be reduced by injecting water (brine) alternated with CO{sub 2} (WAG) and then further reduced by adding foaming agents-surfactants. In Task 1, we studied a unique foam property, selective mobility reduction (SMR), that effectively reduces the effects of reservoir heterogeneity. Selective mobility reduction creates a more uniform displacement by decreasing CO{sub 2} mobility in higher permeability zones more than in lower permeability zones.

  10. Improved efficiency of miscible CO{sub 2} floods and enhanced prospects for CO{sub 2} flooding heterogeneous reservoirs. Annual report, June 1, 1997--May 31, 1998

    SciTech Connect

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

    1998-07-01

    The goal of this project is to improve the efficiency of miscible CO{sub 2} floods and enhance the prospects for flooding heterogeneous reservoirs. This report provides results of the first year of the three-year project that will be exploring three principle areas: (1) Fluid and matrix interactions (understanding the problems): interfacial tension (IFT), phase behavior, miscibility, capillary number, injectivity, wettability, and gravity drainage; (2) Conformance control/sweep efficiency (solving the problems): reduction of mobility using foam, diversion by selective mobility reduction (SMR) using foam, improved injectivity, alternating water and gas injection, and using horizontal wells; and (3) Reservoir simulation for improved oil recovery (predicting results): gravity drainage, SMR, CO{sub 2}-foam flooding, interfacial tension, injectivity profile, horizontal wells, and naturally fractured reservoirs. Studies of surfactant foam quality were performed during this first year. Simulation studies on a foam pilot area resulted in an acceptable history match model. The results confirm that the communication path between the foam injection well and a production well had a strong impact on the production performance. A laboratory study to aid in the development of a gravity drainage reservoir was undertaken on the Wellman Unit. Experiments were begun meant to duplicate situations of injectivity loss in WAG flooding and identify factors affecting the injectivity loss. The preliminary results indicate that for a given rock the injectivity loss depends on oil saturation in the core during WAG flooding. The injectivity loss is higher in cores with high in-situ oil saturations during WAG flooding. This effect is being verified by more experimental data.

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

    SciTech Connect

    Bou-Mikael, Sami

    2002-02-05

    The main objective of the Port Neches Project was to determine the feasibility and producibility of CO2 miscible flooding techniques enhanced with horizontal drilling applied to a Fluvial Dominated Deltaic reservoir. The second was to disseminate the knowledge gained through established Technology Transfer mechanisms to support DOE's programmatic objectives of increasing domestic oil production and reducing abandonment of oil fields.

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

    SciTech Connect

    Bou-Mikael, Sami

    2002-02-05

    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.

  13. Review of miscible flood performance, intisar ''D'' field, socialist people's Libyan Arab Jamahiriya

    SciTech Connect

    Des Brisay, C.L.; Elghussein, B.F.; Holst, P.H.; Misellati, A.

    1982-08-01

    One of the largest miscible gas injection projects in the world is in its 12th year in the Intisar ''D'' field in the Socialist People's Libyan Arab Jamahiriya. As of March 31, 1981, cumulative oil production totaled 890 MMbbl (141.4 X 10/sup 6/ m/sup 3/) of oil, or 56% recovery of the estimated stock-tank original oil in place (OOIP). This past performance and recent simulation studies indicate a final recovery efficiency on the order of 70%.

  14. Improved Efficiency of Miscible CO{sub 2} Floods and Enhanced Prospects for CO{sub 2} Flooding Heterogeneous Reservoirs

    SciTech Connect

    Boyun Guo; David S. Schechter; Jyun-Syung Tsau; Reid B. Grigg; Shih-Hsien Chang

    1997-10-31

    This work will examine three major areas in which CO{sub 2} flooding can be improved: fluid and matrix interactions, conformance control/sweep efficiency, and reservoir simulation for improved oil recovery. The first full quarter of this project has been completed. We began examining synergistic affects of mixed surfactant versus single surfactant systems to enhance the properties of foams used for improving oil recovery in CO{sub 2} floods. The purpose is to reduce the concentration of surfactants or finding less expensive surfactants. Also, we are examining the effect of oil saturation on the development of foam in CO{sub 2}-surfactant solution systems. CO{sub 2} flooding of low permeability, vugular, and fracture reservoirs are another major thrust of this project. Work conducted this quarter involved simulating gravity stable floods using large core samples; results showed excellent recovery in a low permeability vugular core.

  15. IMPROVED MISCIBLE NITROGEN FLOOD PERFORMANCE UTILIZING ADVANCED RESERVOIR CHARACTERIZATION AND HORIZONTAL LATERALS IN A CLASS I RESERVOIR - EAST BINGER (MARCHAND) UNIT

    SciTech Connect

    Joe Sinner

    2002-03-26

    The objective of this project is two-fold. It will demonstrate use of nitrogen as a widely available, cost-effective and environmentally superior injectant for miscible floods. It will also demonstrate the effectiveness of horizontal wellbores in reducing gas breakthrough and cycling. It is expected that the demonstration will lead to implementation of nitrogen injection projects in areas without readily available carbon dioxide sources. Technology transfer will occur throughout the project.

  16. Improved Miscible Nitrogen Flood Performance Utilizing Advanced Reservoir Characterization and Horizontal Laterals in a Class I Reservoir - East Binger (Marchand) Unit

    SciTech Connect

    Joe Sinner

    2004-06-30

    The DOE-sponsored project at the East Binger Unit is an investigation into the benefits of reservoir characterization and horizontal wells in this particular setting of geologic and recovery method. The geologic setting is a tight (average porosity of 7% and average permeability of less than 1 millidarcy) Pennsylvanian-age sandstone at about 10,000 feet, and the recovery method is a miscible nitrogen flood. The projected oil recovery of the East Binger Unit, prior to the initiation of this project, was about 25%. Gravity segregation of nitrogen and crude oil was believed to be the principal cause of the poor sweep efficiency, and it was envisioned that with horizontal producing wells in the lower portion of the reservoir and horizontal injection wells near the top, the process could be converted from a lateral displacement process to a vertical displacement/gravity assisted process. Through the characterization and field development work completed in Budget Periods 1 and 2, Binger Operations, LLC (BOL) has developed a different interpretation of the sweep problem as well as a different approach to improving recovery. The sweep problem is now believed to be one of an areal nature, due to a combination of natural and hydraulic fracturing. Vertical wells have provided a much better economic return than have the horizontal wells. The natural and hydraulic fracturing manifests itself as a direction of higher permeability, and the flood is being converted to a line drive flood aligned with this orientation. Consistent with this concept, horizontal wells have been drilled along the line of the fracture orientation, such that hydraulic fracturing leads to 'longitudinal' fractures, in line with the wellbore. As such, the hydraulically fractured horizontal wells are not significantly different than hydraulically fractured vertical wells - save for the potential for a much longer fracture face. This Topical Report contains data from new wells, plus new and updated production

  17. 4D seismic to image a thin carbonate reservoir during a miscible C02 flood: Hall-Gurney Field, Kansas, USA

    USGS Publications Warehouse

    Raef, A.E.; Miller, R.D.; Franseen, E.K.; Byrnes, A.P.; Watney, W.L.; Harrison, W.E.

    2005-01-01

    The movement of miscible CO2 injected into a shallow (900 m) thin (3.6-6m) carbonate reservoir was monitored using the high-resolution parallel progressive blanking (PPB) approach. The approach concentrated on repeatability during acquisition and processing, and use of amplitude envelope 4D horizon attributes. Comparison of production data and reservoir simulations to seismic images provided a measure of the effectiveness of time-lapse (TL) to detect weak anomalies associated with changes in fluid concentration. Specifically, the method aided in the analysis of high-resolution data to distinguish subtle seismic characteristics and associated trends related to depositional lithofacies and geometries and structural elements of this carbonate reservoir that impact fluid character and EOR efforts.

  18. Study of hydrocarbon miscible solvent slug injection process for improved recovery of heavy oil from Schrader Bluff Pool, Milne Point Unit, Alaska. [Quarterly] report, January 1, 1993--March 31, 1993

    SciTech Connect

    Sharma, G.D.

    1993-06-01

    The ultimate objective of this three-year research project is to evaluate the performance of the hydrocarbon miscible solvent slug process and to assess the feasibility of this process for improving recovery of heavy oil from Schrader Bluff reservoir. This will be accomplished through measurement of PVT and fluid properties of Schrader Bluff oil, determination of phase behavior of Schrader Bluff oil solvent mixtures, asphaltene precipitation tests, slim tube displacement tests, core flood experiments and reservoir simulation studies. The expected results from this project include: determination of optimum hydrocarbon solvent composition suitable for hydrocarbon miscible solvent slug displacement process, optimum slug sizes of solvent needed, solvent recovery factor, solvent requirements, extent and timing of solvent recycle, displacement and sweep efficiency to be achieved and oil recovery. Work performed during quarter includes preliminary reservoir fluid characterization and multiple contact test runs using equation-of-state (EOS) simulator. Reservoir fluid samples are being acquired from Conoco Inc., and the process is expected to continue through the next quarter. Also, the experimental apparatus for the displacement study was set up.

  19. Improved efficiency of miscible CO{sub 2} floods and enhanced prospects for CO{sub 2} flooding heterogeneous reservoirs. Quarterly technical progress report, April 1, 1995--June 30, 1995

    SciTech Connect

    Grigg, R.B.; Heller, J.P.; Schechter, D.S.

    1995-09-01

    The objective of this experimental research is to improve the effectiveness of CO{sub 2} flooding in heterogeneous reservoirs. Activities are being conducted in three closely related areas: (1) exploring further the applicability of selective mobility reduction (SMR) in the use of foam flooding, (2) exploring the possibility of higher economic viability of floods at slightly reduced CO{sub 2} injection pressures, and (3) taking advantage of gravitational forces during low interfacial tension (IFT), CO{sub 2} flooding in tight, vertically fractured reservoirs. Progress made this quarter in the following tasks is described: Task 1 CO{sub 2}-foams for selective mobility reduction; task 2 reduction of the amount of CO{sub 2} required in CO{sub 2} flooding; and Task 3 low IFT processes and gas injection in fractured reservoirs.

  20. 4D seismic monitoring of the miscible CO2 flood of Hall-Gurney Field, Kansas, U.S

    USGS Publications Warehouse

    Raef, A.E.; Miller, R.D.; Byrnes, A.P.; Harrison, W.E.

    2004-01-01

    A cost-effective, highly repeatable, 4D-optimized, single-pattern/patch seismic data-acquisition approach with several 3D data sets was used to evaluate the feasibility of imaging changes associated with the " water alternated with gas" (WAG) stage. By incorporating noninversion-based seismic-attribute analysis, the time and cost of processing and interpreting the data were reduced. A 24-ms-thick EOR-CO 2 injection interval-using an average instantaneous frequency attribute (AIF) was targeted. Changes in amplitude response related to decrease in velocity from pore-fluid replacement within this time interval were found to be lower relative to background values than in AIF analysis. Carefully color-balanced AIF-attribute maps established the overall area affected by the injected EOR-CO2.

  1. 44 CFR 78.6 - Flood Mitigation Plan approval process.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 44 Emergency Management and Assistance 1 2012-10-01 2011-10-01 true Flood Mitigation Plan approval..., DEPARTMENT OF HOMELAND SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program FLOOD MITIGATION ASSISTANCE § 78.6 Flood Mitigation Plan approval process. The State POC will forward all...

  2. 44 CFR 78.6 - Flood Mitigation Plan approval process.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Flood Mitigation Plan..., DEPARTMENT OF HOMELAND SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program FLOOD MITIGATION ASSISTANCE § 78.6 Flood Mitigation Plan approval process. The State POC will forward all...

  3. 44 CFR 78.6 - Flood Mitigation Plan approval process.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 44 Emergency Management and Assistance 1 2013-10-01 2013-10-01 false Flood Mitigation Plan..., DEPARTMENT OF HOMELAND SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program FLOOD MITIGATION ASSISTANCE § 78.6 Flood Mitigation Plan approval process. The State POC will forward all...

  4. 44 CFR 78.6 - Flood Mitigation Plan approval process.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 44 Emergency Management and Assistance 1 2014-10-01 2014-10-01 false Flood Mitigation Plan..., DEPARTMENT OF HOMELAND SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program FLOOD MITIGATION ASSISTANCE § 78.6 Flood Mitigation Plan approval process. The State POC will forward all...

  5. 44 CFR 78.6 - Flood Mitigation Plan approval process.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 44 Emergency Management and Assistance 1 2011-10-01 2011-10-01 false Flood Mitigation Plan..., DEPARTMENT OF HOMELAND SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program FLOOD MITIGATION ASSISTANCE § 78.6 Flood Mitigation Plan approval process. The State POC will forward all...

  6. Post waterflood CO{sub 2} miscible flood in light oil, fluvial-dominated deltaic reservoir. Annual report, October 1, 1993--September 30, 1994

    SciTech Connect

    Bou-Mikael, S.

    1995-07-01

    Texaco Exploration and Production Inc. (TEPI) and the U.S. Department of Energy (DOE) entered into a cost sharing cooperative agreement to conduct an Enhanced Oil Recovery demonstration project at Port Neches. The field is located in Orange County near Beaumont, Texas. The project will demonstrate the effectiveness of the CO{sub 2}, miscible process in Fluvial Dominated Deltaic reservoirs. It will also evaluate the use of horizontal CO{sub 2} injection wells to improve the overall sweep efficiency. A data base of FDD reservoirs for the gulf coast region will be developed by LSU, using a screening model developed by Texaco Research Center in Houston. Finally, the results and the information gained from this project will be disseminated throughout the oil industry via a series of SPE papers and industry open forums. Reservoir characterization efforts for the Marginulina sand, are in progress utilizing conventional and advanced technologies including 3-D seismic. Sidewall and conventional. cores were cut and analyzed, lab tests were conducted on reservoir fluids, reservoir BHP pressure and reservoir voidage were monitored as shown. Texaco is utilizing the above data to develop a Stratamodel to best describe and characterize the reservoir and to use it as an input for the compositional simulator. The current compositional model is being revised to integrate the new data from the 3-D seismic and field performance under CO{sub 2} injection, to ultimately develop an accurate economic model. All facilities work has been completed and placed in service including the CO{sub 2} pipeline and metering equipment, CO{sub 2} injection and production equipment, water injection equipment, well work and injection/production lines. The horizontal injection well was drilled and completed on January 15, 1994. CO{sub 2} purchases from Cardox continue at an average rate of 3600 MCFD. The CO{sub 2} is being injected at line pressure of 1350 psi.

  7. An investigation into the influence of drug-polymer interactions on the miscibility, processability and structure of polyvinylpyrrolidone-based hot melt extrusion formulations.

    PubMed

    Chan, Siok-Yee; Qi, Sheng; Craig, Duncan Q M

    2015-12-30

    While hot melt extrusion is now established within the pharmaceutical industry, the prediction of miscibility, processability and structural stability remains a pertinent issue, including the issue of whether molecular interaction is necessary for suitable performance. Here we integrate the use of theoretical and experimental drug-polymer interaction assessment with determination of processability and structure of dispersions in two polyvinylpyrrolidone-based polymers (PVP and PVP vinyl acetate, PVPVA). Caffeine and paracetamol were chosen as model drugs on the basis of their differing hydrogen bonding potential with PVP. Solubility parameter and interaction parameter calculations predicted a greater miscibility for paracetamol, while ATR-FTIR confirmed the hydrogen bonding propensity of the paracetamol with both polymers, with little interaction detected for caffeine. PVP was found to exhibit greater interaction and miscibility with paracetamol than did PVPVA. It was noted that lower processing temperatures (circa 40°C below the Tg of the polymer alone and Tm of the crystalline drug) and higher drug loadings with associated molecular dispersion up to 50% w/w were possible for the paracetamol dispersions, although molecular dispersion with the non-interactive caffeine was noted at loadings up to 20% w./w. A lower processing temperature was also noted for caffeine-loaded systems despite the absence of detectable interactions. The study has therefore indicated that theoretical and experimental detection of miscibility and drug-polymer interactions may lead to insights into product processing and extrudate structure, with direct molecular interaction representing a helpful but not essential aspect of drug-polymer combination prediction.

  8. Glacier lake outburst floods - modelling process chains

    NASA Astrophysics Data System (ADS)

    Schaub, Yvonne; Huggel, Christian; Haeberli, Wilfried

    2013-04-01

    New lakes are forming in high-mountain areas all over the world due to glacier recession. Often they will be located below steep, destabilized flanks and are therefore exposed to impacts from rock-/ice-avalanches. Several events worldwide are known, where an outburst flood has been triggered by such an impact. In regions such as in the European Alps or in the Cordillera Blanca in Peru, where valley bottoms are densely populated, these far-travelling, high-magnitude events can result in major disasters. For appropriate integral risk management it is crucial to gain knowledge on how the processes (rock-/ice-avalanches - impact waves in lake - impact on dam - outburst flood) interact and how the hazard potential related to corresponding process chains can be assessed. Research in natural hazards so far has mainly concentrated on describing, understanding, modeling or assessing single hazardous processes. Some of the above mentioned individual processes are quite well understood in their physical behavior and some of the process interfaces have also been investigated in detail. Multi-hazard assessments of the entire process chain, however, have only recently become subjects of investigations. Our study aims at closing this gap and providing suggestions on how to assess the hazard potential of the entire process chain in order to generate hazard maps and support risk assessments. We analyzed different types of models (empirical, analytical, physically based) for each process regarding their suitability for application in hazard assessments of the entire process chain based on literature. Results show that for rock-/ice-avalanches, dam breach and outburst floods, only numerical, physically based models are able to provide the required information, whereas the impact wave can be estimated by means of physically based or empirical assessments. We demonstrate how the findings could be applied with the help of a case study of a recent glacier lake outburst event at Laguna

  9. Study of hydrocarbon miscible solvent slug injection process for improved recovery of heavy oil from Schrader Bluff Pool, Milne Point Unit, Alaska. Final report

    SciTech Connect

    1995-11-01

    The National Energy Strategy Plan (NES) has called for 900,000 barrels/day production of heavy oil in the mid-1990s to meet our national needs. To achieve this goal, it is important that the Alaskan heavy oil fields be brought to production. Alaska has more than 25 billion barrels of heavy oil deposits. Conoco, and now BP Exploration have been producing from Schrader Bluff Pool, which is part of the super heavy oil field known as West Sak Field. Schrader Bluff reservoir, located in the Milne Point Unit, North Slope of Alaska, is estimated to contain up to 1.5 billion barrels of (14 to 21{degrees}API) oil in place. The field is currently under production by primary depletion; however, the primary recovery will be much smaller than expected. Hence, waterflooding will be implemented earlier than anticipated. The eventual use of enhanced oil recovery (EOR) techniques, such as hydrocarbon miscible solvent slug injection process, is vital for recovery of additional oil from this reservoir. The purpose of this research project was to determine the nature of miscible solvent slug which would be commercially feasible, to evaluate the performance of the hydrocarbon miscible solvent slug process, and to assess the feasibility of this process for improved recovery of heavy oil from Schrader Bluff reservoir. The laboratory experimental work includes: slim tube displacement experiments and coreflood experiments. The components of solvent slug includes only those which are available on the North Slope of Alaska.

  10. Gas miscible displacement enhanced oil recovery: Technology status report

    SciTech Connect

    Not Available

    1986-10-01

    Gas miscible displacement enhanced oil recovery research is conducted by the US Department of Energy's Morgantown Energy Technology Center to advance the application of miscible carbon dioxide flooding. This research is an integral part of a multidisciplinary effort to improve the technology for producing additional oil from US resources. This report summarizes the problems of the technology and the 1986 results of the ongoing research that was conducted to solve those problems. Poor reservoir volumetric sweep efficiency is the major problem associated with gas flooding and all miscible displacements. This problem results from the channeling and viscous fingering that occur due to the large differences between viscosity or density of the displacing and displaced fluids (i.e., carbon dioxide and oil, respectively). Simple modeling and core flooding studies indicate that, because of differences in fluid viscosities, breakthrough can occur after only 30% of the total pore volume (PV) of the rock has been injected with gas, while field tests have shown breakthrough occurring much earlier. The differences in fluid densities lead to gravity segregation. The lower density carbon dioxide tends to override the residual fluids in the reservoir. This process would be considerably more efficient if a larger area of the reservoir could be contacted by the gas. Current research has focused on the mobility control, computer simulation, and reservoir heterogeneity studies. Three mobility control methods have been investigated: (1) the use of polymers for direct thickening of high-density carbon dioxide, (2) mobile ''foam-like dispersions'' of carbon dioxide and an aqueous surfactant, and (3) in situ deposition of chemical precipitates. 22 refs., 14 figs., 6 tabs.

  11. 3-D hydrodynamic modelling of flood impacts on a building and indoor flooding processes

    NASA Astrophysics Data System (ADS)

    Gems, Bernhard; Mazzorana, Bruno; Hofer, Thomas; Sturm, Michael; Gabl, Roman; Aufleger, Markus

    2016-06-01

    Given the current challenges in flood risk management and vulnerability assessment of buildings exposed to flood hazards, this study presents three-dimensional numerical modelling of torrential floods and its interaction with buildings. By means of a case study application, the FLOW-3D software is applied to the lower reach of the Rio Vallarsa torrent in the village of Laives (Italy). A single-family house on the flood plain is therefore considered in detail. It is exposed to a 300-year flood hydrograph. Different building representation scenarios, including an entire impervious building envelope and the assumption of fully permeable doors, light shafts and windows, are analysed. The modelling results give insight into the flooding process of the building's interior, the impacting hydrodynamic forces on the exterior and interior walls, and further, they quantify the impact of the flooding of a building on the flow field on the surrounding flood plain. The presented study contributes to the development of a comprehensive physics-based vulnerability assessment framework. For pure water floods, this study presents the possibilities and limits of advanced numerical modelling techniques within flood risk management and, thereby, the planning of local structural protection measures.

  12. Flooding

    MedlinePlus

    ... flooding Prepare for flooding For communities, companies, or water and wastewater facilities: Suggested activities to help facilities ... con monóxido de carbono. Limit contact with flood water. Flood water may have high levels of raw ...

  13. Spreading of miscible liquids

    NASA Astrophysics Data System (ADS)

    Walls, Daniel J.; Haward, Simon J.; Shen, Amy Q.; Fuller, Gerald G.

    2016-05-01

    Miscible liquids commonly contact one another in natural and technological situations, often in the proximity of a solid substrate. In the scenario where a drop of one liquid finds itself on a solid surface and immersed within a second, miscible liquid, it will spread spontaneously across the surface. We show experimental findings of the spreading of sessile drops in miscible environments that have distinctly different shape evolution and power-law dynamics from sessile drops that spread in immiscible environments, which have been reported previously. We develop a characteristic time to scale radial data of the spreading sessile drops based on a drainage flow due to gravity. This time scale is effective for a homologous subset of the liquids studied. However, it has limitations when applied to significantly chemically different, yet miscible, liquid pairings; we postulate that the surface energies between each liquid and the solid surface becomes important for this other subset of the liquids studied. Initial experiments performed with pendant drops in miscible environments support the drainage flow observed in the sessile drop systems.

  14. Miscible polymer blend dynamics

    NASA Astrophysics Data System (ADS)

    Pathak, Jai Avinash

    The segmental and terminal dynamics of miscible polymer blends have been systematically investigated with pointed experiments to test dichotomous literature ideas on the origin of dynamic heterogeneity in these systems. Segmental dynamics have been studied by dielectric spectroscopy, while terminal dynamics have been studied by oscillatory shear rheology. It has been found that when composition fluctuations are suppressed, dynamic heterogeneities, such as the failure of time-temperature superposition (tTS), are also suppressed. This observation lends credence to the ideas of Fischer and Kumar that spontaneous composition fluctuations in miscible blends profoundly affect their segmental dynamics. In addition, data acquired in this study on two model weakly-interacting miscible polyolefin blends, were combined with literature data to show that breakdown of tTS worsens with increasing dynamic asymmetry (intrinsic differences in component dynamics) in weakly-interacting miscible blends. This observation is adduced as evidence for the role of dynamic asymmetry in miscible blend dynamics, in addition to the role of composition fluctuations. Finally, attempts were made to use information on component segmental dynamics, as obtained from the composition fluctuation model of Kumar, to predict terminal dynamics in miscible blends. In this regard, the composition fluctuation model was first used to model segmental dynamics in a model weakly-interacting blend. Then, experimental segmental and terminal dynamics data were used to identify a possible segmental time-scale which may control terminal relaxation of a chain in a blend. This timescale was found to lie on the long-time end of the distribution of segmental relaxation times for each component. It was calculated from the segmental relaxation time distribution for each component of a miscible blend as the average-longest segmental time experienced by the monomers of a given chain. Using the Doi-Edwards tube model, the

  15. Comparison of oil removal in surfactant alternating gas with water alternating gas, water flooding and gas flooding in secondary oil recovery process

    PubMed Central

    Salehi, Mehdi Mohammad; Safarzadeh, Mohammad Amin; Sahraei, Eghbal; Nejad, Seyyed Alireza Tabatabaei

    2014-01-01

    Growing oil prices coupled with large amounts of residual oil after operating common enhanced oil recovery methods has made using methods with higher operational cost economically feasible. Nitrogen is one of the gases used in both miscible and immiscible gas injection process in oil reservoir. In heterogeneous formations gas tends to breakthrough early in production wells due to overriding, fingering and channeling. Surfactant alternating gas (SAG) injection is one of the methods commonly used to decrease this problem. Foam which is formed on the contact of nitrogen and surfactant increases viscosity of injected gas. This increases the oil–gas contact and sweep efficiency, although adsorption of surfactant on rock surface can causes difficulties and increases costs of process. Many parameters must be considered in design of SAG process. One of the most important parameters is SAG ratio that should be in optimum value to improve the flooding efficiency. In this study, initially the concentration of surfactant was optimized due to minimization of adsorption on rock surface which results in lower cost of surfactant. So, different sodium dodecyl sulfate (SDS) concentrations of 100, 500, 1000, 2000, 3000 and 4000 ppm were used to obtain the optimum concentration at 70 °C and 144.74×105 Pa. A simple, clean and relatively fast spectrophotometric method was used for determination of surfactant which is based on the formation of an ion-pair. Then the effect of surfactant to gas volume ratio on oil recovery in secondary oil recovery process during execution of immiscible surfactant alternating gas injection was examined experimentally. The experiments were performed with sand pack under certain temperature, pressure and constant rate. Experiments were performed with surfactant to gas ratio of 1:1, 1:2, 1:3, 2:1 and 3:1 and 1.2 pore volume injected. Then, comparisons were made between obtained results (SAG) with water flooding, gas flooding and water alternating gas

  16. Comparison of oil removal in surfactant alternating gas with water alternating gas, water flooding and gas flooding in secondary oil recovery process.

    PubMed

    Salehi, Mehdi Mohammad; Safarzadeh, Mohammad Amin; Sahraei, Eghbal; Nejad, Seyyed Alireza Tabatabaei

    2014-08-01

    Growing oil prices coupled with large amounts of residual oil after operating common enhanced oil recovery methods has made using methods with higher operational cost economically feasible. Nitrogen is one of the gases used in both miscible and immiscible gas injection process in oil reservoir. In heterogeneous formations gas tends to breakthrough early in production wells due to overriding, fingering and channeling. Surfactant alternating gas (SAG) injection is one of the methods commonly used to decrease this problem. Foam which is formed on the contact of nitrogen and surfactant increases viscosity of injected gas. This increases the oil-gas contact and sweep efficiency, although adsorption of surfactant on rock surface can causes difficulties and increases costs of process. Many parameters must be considered in design of SAG process. One of the most important parameters is SAG ratio that should be in optimum value to improve the flooding efficiency. In this study, initially the concentration of surfactant was optimized due to minimization of adsorption on rock surface which results in lower cost of surfactant. So, different sodium dodecyl sulfate (SDS) concentrations of 100, 500, 1000, 2000, 3000 and 4000 ppm were used to obtain the optimum concentration at 70 °C and 144.74×10(5) Pa. A simple, clean and relatively fast spectrophotometric method was used for determination of surfactant which is based on the formation of an ion-pair. Then the effect of surfactant to gas volume ratio on oil recovery in secondary oil recovery process during execution of immiscible surfactant alternating gas injection was examined experimentally. The experiments were performed with sand pack under certain temperature, pressure and constant rate. Experiments were performed with surfactant to gas ratio of 1:1, 1:2, 1:3, 2:1 and 3:1 and 1.2 pore volume injected. Then, comparisons were made between obtained results (SAG) with water flooding, gas flooding and water alternating gas

  17. Shear-stabilized emulsion flooding process

    SciTech Connect

    Carpenter, C.W.; Reed, R.L.

    1982-06-29

    Additional amounts of crude oil are recovered from a subterranean formation by flooding with a translucent emulsion comprising an upper- or middle-phase microemulsion as an external phase and a polymer-containing brine solution as an internal phase. The translucent emulsion tends to coalesce into its component phases under conditions of no shear, but is stabilized by low shears such as those imposed on fluids flowing through a subterranean formation.

  18. Geologic investigations in support of a proposed carbon dioxide miscible flood in the MCA unit Maljamar-Grayburg/San Andres Pool, Lea County, New Mexico. Final report

    SciTech Connect

    Foster, R.W.

    1984-03-01

    Presented are the results of a detailed geologic study of the principal oil-bearing intervals within the Grayburg and San Andres Formations at the MCA Unit of the Maljamar Field. The work includes an interpretation of the depositional environment for selected intervals as determined from core and thinsection studies. The conclusion is that the sediments were deposited along a prograding shore line and represent near shore marine, intertidal, and supratidal deposits. An evaluation of porosity and permeability as related to core interpretations led to the conclusion that conditions favorable for the accumulation of oil were almost entirely restricted to nearshore marine deposits. Intertidal and supratidal rocks were not favorable for the development of effective porosity. Although many types of porosity are present, the most important in both the dolomite and sandstone reservoirs is secondary vuggy porosity. The Grayburg includes at least 14 sandstone reservoirs and the San Andres numerous dolomite zones and one sandstone interval. The distribution and effective porosity of important zones as related to the carbon dioxide flood are shown in maps and cross sections. 14 references, 64 figures, 11 tables.

  19. Gas miscible displacement enhanced oil recovery: Technology status report

    SciTech Connect

    Watts, R.J.; Komar, C.A.

    1989-01-01

    Research on gas flooding and miscible displacement, with an emphasis on improvement of CO/sub 2/ flood performance is described. Low reservoir volumetric sweep efficiency is the major problem associated with gas flooding and all miscible displacements. CO/sub 2/ flooding would be considerably more efficient if a larger area of the reservoir could be contacted by the gas. Current research has focused on mobility control, computer simulation, and reservoir heterogeneity studies. Three mobility control methods have been investigated: the use of polymers for direct thickening of high-density carbon dioxide, mobile ''foam-like dispersions'' of carbon dioxide and aqueous surfactant, and in situ deposition of chemical precipitates. 17 refs., 22 figs., 8 tabs.

  20. Post waterflood CO2 miscible flood in light oil fluvial - dominated deltaic reservoirs. Technical progress report, October 1, 1994--December 30, 1994. 1st Quarter, fiscal year 1995

    SciTech Connect

    1994-01-15

    Production is averaging about 450 BOPD for the quarter. The fluctuation was primarily due to a temporary shutdown of CO{sub 2} delivery and maturing of the first WAG cycle. CO{sub 2} and water injection were reversed again in order to optimize changing yields and water cuts in the producing wells. Measured BHP was close to the anticipated value. A limited CO{sub 2} volume of 120 MMCF was injected to stimulate well Kuhn No. 6 to test the Huff-Puff process, since the well did not respond to CO{sub 2} injection from the main reservoir. The well will be placed on February 1, 1995. Total CO{sub 2} injection averaged this quarter about 8.8 MMCFD, including 3.6 MMCFD purchased CO{sub 2} from Cardox. The stratigraphy of the sand deposits is also discussed.

  1. Study of hydrocarbon miscible solvent slug injection process for improved recovery of heavy oil from Schrader Bluff Pool, Milne Point Unit, Alaska. Annual report, January 1, 1994--December 31, 1994

    SciTech Connect

    Sharma, G.D.

    1995-07-01

    Alaska is the second largest oil producing state in the nation and currently contributes nearly 24% of the nations oil production. It is imperative that Alaskan heavy oil fields be brought into production. Schrader Bluff reservoir, located in the Milne Point Unit, which is part of the heavy oil field known as West Sak is estimated to contain 1.5 billion barrels of (14 to 21 degree API) oil-in-place. The field is currently under production by primary depletion. The eventual implementation of enhanced oil recovery (EOR) techniques will be vital for the recovery of additional oil from this reservoir. The availability of hydrocarbon gases (solvents) on the Alaska North Slope make the hydrocarbon miscible solvent injection process an important consideration for the EOR project in Schrader Bluff reservoir. Since Schrader Bluff oil is heavy and viscous, a water-alternating-gas (WAG) type of process for oil recovery is appropriate since such a process tends to derive synergetic benefits from both water injection (which provides mobility control and improvement in sweep efficiency) and miscible gas injection (which provides improved displacement efficiency). A miscible solvent slug injection process rather than continuous solvent injection is considered appropriate. Slim tube displacement studies, PVT data and asphaltene precipitation studies are needed for Schrader bluff heavy oil to define possible hydrocarbon solvent suitable for miscible solvent slug displacement process. Coreflood experiments are also needed to determine the effect of solvent slug size, WAG ratio and solvent composition on the recovery and solvent breakthrough. A compositional reservoir simulation study will be conducted later to evaluate the complete performance of the hydrocarbon solvent slug process and to assess the feasibility of this process for improving recovery of heavy oil from Schrader Bluff reservoir.

  2. Flooding and Flood Management

    USGS Publications Warehouse

    Brooks, K.N.; Fallon, J.D.; Lorenz, D.L.; Stark, J.R.; Menard, Jason; Easter, K.W.; Perry, Jim

    2011-01-01

    Floods result in great human disasters globally and nationally, causing an average of $4 billion of damages each year in the United States. Minnesota has its share of floods and flood damages, and the state has awarded nearly $278 million to local units of government for flood mitigation projects through its Flood Hazard Mitigation Grant Program. Since 1995, flood mitigation in the Red River Valley has exceeded $146 million. Considerable local and state funding has been provided to manage and mitigate problems of excess stormwater in urban areas, flooding of farmlands, and flood damages at road crossings. The cumulative costs involved with floods and flood mitigation in Minnesota are not known precisely, but it is safe to conclude that flood mitigation is a costly business. This chapter begins with a description of floods in Minneosta to provide examples and contrasts across the state. Background material is presented to provide a basic understanding of floods and flood processes, predication, and management and mitigation. Methods of analyzing and characterizing floods are presented because they affect how we respond to flooding and can influence relevant practices. The understanding and perceptions of floods and flooding commonly differ among those who work in flood forecasting, flood protection, or water resource mamnagement and citizens and businesses affected by floods. These differences can become magnified following a major flood, pointing to the need for better understanding of flooding as well as common language to describe flood risks and the uncertainty associated with determining such risks. Expectations of accurate and timely flood forecasts and our ability to control floods do not always match reality. Striving for clarity is important in formulating policies that can help avoid recurring flood damages and costs.

  3. What Drives Blend Miscibility?

    NASA Astrophysics Data System (ADS)

    White, Ronald; Lipson, Jane

    2014-03-01

    With no mixture data available, can one predict phase behavior in polymeric systems based on pure component information only? Due to the very weak entropic drive for large molecules to mix, predicting and understanding miscibility behavior is indeed very difficult. However, while not perfect, some a priori insight is attainable when pure component properties are analyzed within the framework of a theoretical model. A theory provides a platform, allowing one to define quantities and other measures that may not always be directly measurable, but, are physically appealing and insightful none-the-less. Are there properties that can explain for example, why a polymer like polyisobutylene (PIB) exhibits such different phase behavior compared to other polyolefins? Applying our simple lattice-based equation of state, we have recently analyzed a large number of different polymers. In this talk we will present insights from trends and patterns we have observed. Work supported by the National Science Foundation.

  4. USING PHASE DIAGRAMS TO PREDICT THE PERFORMANCE OF COSOLVENT FLOODS FOR NAPL REMEDIATION

    EPA Science Inventory

    Cosolvent flooding using water miscible solvents such as alcohols has been proposed as an in-situ NAPL remediation technique. This process is conceptually similar to enhanced oil recovery (EOR) using alcohols and some surfactant formulations. As a result of interest in the EOR ...

  5. Investigations of infiltration processes from flooded areas by column experiments

    NASA Astrophysics Data System (ADS)

    Mohrlok, U.; Bethge, E.; Golalipour, A.

    2009-04-01

    In case of inundation of flood plains during flood events there is an increased risk of groundwater contamination due to infiltration of increasingly polluted river water. Specifically in densely populated regions, this groundwater may be used as source for drinking water supply. For the evaluation of this a detailed quantitative understanding of the infiltration processes under such conditions is required. In this context the infiltration related to a flood event can be described by three phases. The first phase is defined by the saturation of the unsaturated soils. Within the second phase infiltration takes place under almost saturated conditions determined by the hydraulic load of the flood water level. The drainage of the soils due to falling groundwater table is characterizing the third phase. Investigations by soil columns gave a detailed insight into the infiltration processes caused by flooding. Inflow at the soil top was established by a fixed water table fed by a Mariotte bottle. Free outflow and a groundwater table were used as lower boundary condition. Inflow and outflow volume were monitored. The evolution of the matrix pressure was observed by micro-tensiometers installed at several depths within the soil column. The flow processes during phase one and two were characterized by a tracer test. Some of the experiments were repeated in order to study the influence of preliminary events. Main results were a difference in infiltration due to the lower boundary condition with regard to inflow rate, outflow dynamics and matrix pressure evolution which is directly related to the water content evolution. Further, the influence of preliminary events was different for the different boundary conditions. A replacement of pre-event water could be observed which was confirmed by volume balances calculated for the infiltration experiments. Although these water balances were almost closed significant dynamics of the matrix pressure remained in soil column in the

  6. Floods

    MedlinePlus

    ... quickly, often have a dangerous wall of roaring water. The wall carries rocks, mud, and rubble and can sweep away most things in its path. Be aware of flood hazards no matter where you live, but especially if you live in a low-lying area, near water or downstream from a dam. Although there are ...

  7. Enhancing flood forecasting with the help of processed based calibration

    NASA Astrophysics Data System (ADS)

    Cullmann, Johannes; Krauße, Thomas; Philipp, Andy

    Due to the fact that the required input data are not always completely available and model structures are only a crude description of the underlying natural processes, model parameters need to be calibrated. Calibrated model parameters only reflect a small domain of the natural processes well. This imposes an obstacle on the accuracy of modelling a wide range of flood events, which, in turn is crucial for flood forecasting systems. Together with the rigid model structures of currently available rainfall-runoff models this presents a serious constraint to portraying the highly non-linear transformation of precipitation into runoff. Different model concepts (interflow, direct runoff), or rather the represented processes, such as infiltration, soil water movement etc. are more or less dominating different sections of the runoff spectrum. Most models do not account for such transient characteristics inherent to the hydrograph. In this paper we try to show a way out of the dilemma of limited model parameter validity. Exemplarily, we investigate on the model performance of WaSiM-ETH, focusing on the parameterisation strategy in the context of flood forecasting. In order to compensate for the non-transient parameters of the WaSiM model we propose a process based parameterisation strategy. This starts from a detailed analysis of the considered catchments rainfall-runoff characteristics. Based on a classification of events, WaSiM-ETH is calibrated and validated to describe all the event classes separately. These specific WaSiM-ETH event class models are then merged to improve the model performance in predicting peak flows. This improved catchment modelling can be used to train an artificial intelligence based black box forecasting tool as described in [Schmitz, G.H., Cullmann, J., Görner, W., Lennartz, F., Dröge, W., 2005. PAI-OFF: Eine neue Strategie zur Hochwasservorhersage in schnellreagierenden Einzugsgebieten. Hydrologie und Wasserbewirtschaftung 49, 226

  8. 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

  9. Interpretations of Polymer-Polymer Miscibility.

    ERIC Educational Resources Information Center

    Olabisi, Olagoke

    1981-01-01

    Discusses various aspects of polymeric mixtures, mixtures of structurally different homopolymers, copolymers, terpolymers, and the like. Defines concepts of polymer-polymer miscibility from practical and theoretical viewpoints, and ways of predicting such miscibility. (JN)

  10. Effect of phase behavior on bypassing in enriched gas floods

    SciTech Connect

    Burger, J.E.; Bhogeswara, R.; Mohanty, K.K. )

    1994-05-01

    Enriched gas floods incorporate a complex interaction of heterogeneity, fingering, multiphase flow, and phase behavior. Experiments and simulations indicate that the optimum solvent enrichment in high-viscosity-ratio secondary gas floods can be below minimum miscibility enrichment (MME). The compositional path and resulting mobility profile in multidimensional multiple-contact miscible (MCM) or immiscible floods are different from their 1D counterparts for high-viscosity-ratio floods in heterogeneous media.

  11. Hydro-geological process chain for building a flood scenario

    NASA Astrophysics Data System (ADS)

    Longoni, Laura; Brambilla, Davide; Papini, Monica; Ivanov, Vladislav; Radice, Alessio

    2015-04-01

    Flash-flood events in mountain environments are often related to the transport of large amounts of sediment from the slopes through the stream network. As a consequence, significant morphological changes may occur in rivers during a single, short-duration event, with possibly significant effect on the water elevation. An appropriate hazard evaluation would therefore require the thorough modelling of the flood-related phenomena and of their interconnection. In this context, this work is focused on an attempt of integrated modelling of event-scale water and sediment transport processes for a reference case-study of the Mallero basin in the Italian Alps. The area of the catchments is about 320 square km, the main stream being almost 25 km long and having slopes in the range from 1 to 40 %. A town (Sondrio) is present at the downstream end of the river. In 1987, Sondrio was at risk of inundation due to a combined effect of relatively high discharge and aggradation of the river bed up to 5 m (almost equal to the bankfull depth in the in-town reach). A 100-year flood scenario was produced including (i) a sediment supply model, (ii) a one-dimensional, hydro-morphologic model of the river bed evolution, and (iii) an estimation of the outflowing discharge at river sections where the bank elevation was exceeded by water. Rainfall-runoff transformation was not included into the modelling chain as the 100-year water hydrograph was already available from previous studies. For the sediment production model, a downscaling in time of the Gavrilovic equation was attempted using rainfall estimation from depth-duration-frequency curves, which furnished values in reasonable agreement with some available data. The hydro-morphologic model, based on the Saint-Venant and Exner equations, was preliminarily calibrated against data for bed aggradation measured in 1987. A point of separation was chosen at an appropriate location in the basin, and the sediment yield estimated upstream of this

  12. Field Experiments Aimed To The Analysis of Flood Generation Processes

    NASA Astrophysics Data System (ADS)

    Carriero, D.; Iacobellis, V.; Oliveto, G.; Romano, N.; Telesca, V.; Fiorentino, M.

    The study of the soil moisture dynamics and of the climate-soil-vegetation interac- tion is essential for the comprehension of possible climatic change phenomena, as well as for the analysis of occurrence of extreme hydrological events. In this trend the theoretically-based distribution of floods recently derived by Fiorentino and Ia- cobellis, [ŞNew insights about the climatic and geologic control on the probability distribution of floodsT, Water Resources Research, 2001, 37: 721-730] demonstrated, by an application in some Southern Italy basins, that processes at the hillslope scale strongly influence the basin response by means of the different mechanisms of runoff generation produced by various distributions of partial area contributing. This area is considered as a stochastic variable whose pdf position parameter showed strong de- pendence on the climate as it can seen in the studied basins behavior: in dry zones, where there is the prevalence of the infiltration excess (Horton) mechanism, the basin water loss parameter decreases as basin area increases and the flood peak source area depends on the permeability of soils; in humid zones, with the prevalence of satu- ration excess (Dunne) process, the loss parameter seems independent from the basin area and very sensitive to simple climatic index while only small portion of the area invested by the storm contributes to floods. The purpose of this work is to investigate the consistency of those interpretations by means of field experiments at the hillslope scale to establish a parameterization accounting for soil physical and hydraulic prop- erties, vegetation characteristics and land-use. The research site is the catchment of River Fiumarella di Corleto, which is located in Basilicata Region, Italy, and has a drainage area of approximately 32 km2. The environment has a rather dynamic geo- morphology and very interesting features from the soil-landscape modeling viewpoint [Santini A., A. Coppola, N. Romano, and

  13. Miscibility of lubricants with refrigerants

    SciTech Connect

    Pate, M.B.; Zoz, S.C.; Berkenbosch, L.J.

    1992-07-01

    Miscibility data is being obtained for a variety of non-CFC refrigerants and their potential lubricants. Ten different refrigerants and seven different lubricants are being investigated. Experiments are being performed in two phases: Phase I focuses on performing screening tests and Phase II consists of developing miscibility plots. The miscibility tests are being performed in a test facility consisting of a series of miniature test cells submerged in a constant temperature bath. The bath temperature can be precisely controlled over a temperature range of -50{degrees}C to 100{degrees}C. The test cells are constructed to allow for complete visibility of lubricant-refrigerant mixtures under all test conditions. Early in this reporting period, new procedures for charging the lubricant and refrigerant into the cells for testing were adopted. All of the refrigerants and all but one of the lubricants have been received from the manufacturers. Data obtained to date includes that for R-134a, R142b, R-32, R-134, R-125, and R-143a with four lubricants, namely, two esters and two polypropylene glycols.

  14. Phase separation in transparent liquid-liquid miscibility gap systems

    NASA Technical Reports Server (NTRS)

    Gelles, S. H.; Bhat, B. N.; Laub, R. J.

    1979-01-01

    A program to be carried out on transparent liquid-phase miscibility gap materials was developed for the purpose of acquiring additional insight into the separation process occurring in these systems. The transparency feature allows the reaction to be viewed directly through light scattering and holographic methods.

  15. Process-based distributed hydrological modelling of annual floods in the Upper Zambezi using the Desert Flood Index

    NASA Astrophysics Data System (ADS)

    Meinhardt, Markus; Sven, Kralisch; Manfred, Fink; Daniel, Butchart-Kuhlmann; Anthony, Chabala; Melanie, Fleischer; Jörg, Helmschrot; Wilson, Phiri; Tina, Trautmann; Henry, Zimba; Imasiku, Nyambe

    2016-04-01

    Wetland areas are especially sensitive to changes in hydrological conditions. The catchment of the Luanginga River, a tributary of the Upper Zambezi which covers about 33000 km², shows this characteristic in an exemplary way. Ranging from the Angolan highlands to the Barotse floodplain of the Zambezi River , it is characterized by an annual flow regime and extensive wetland areas. Due to its annual flooding with peak times in April, the area features exceptionally fertile soils with high agricultural production and is further known for its rich cultural heritage, making it especially sensitive to changes of hydrological conditions . To identify possible changes related to projected climate and land management change, especially in the area of the floodplain, there is a need to apply a process-based distributed hydrological model of the annual floods . Remote sensing techniques have shown to be appropriate to identify the extend of the important flooding and were used to validate the model in space and time. The results of this research can be used as a basis with which to provide evidence-based advice and information for all decision-makers and stakeholders in the region. For this assessment , such a modelling approach is applied to adequately represent hydrological processes and to address key water resources management issues at sub-basin levels. Introducing a wetland simulation extension, the model allows to represent the annual flood regime of the system and thus to address the effect of climate change and upstream land use changes on flow regimes in the downstream watershed. In order to provide a basis for model validation and calibration, the inundated area was determined using the Desert Flood Index (DFI), which was generated from a time series of Landsat images. We will give a short introduction to the study area and related water resources management problems, present the intended model structure and show first simulations and model validation results

  16. Comparative hazard analysis of processes leading to remarkable flash floods (France, 1930-1999)

    NASA Astrophysics Data System (ADS)

    Boudou, M.; Lang, M.; Vinet, F.; Cœur, D.

    2016-10-01

    Flash flood events are responsible for large economic losses and lead to fatalities every year in France. This is especially the case in the Mediterranean and oversea territories/departments of France, characterized by extreme hydro-climatological features and with a large part of the population exposed to flood risks. The recurrence of remarkable flash flood events, associated with high hazard intensity, significant damage and socio-political consequences, therefore raises several issues for authorities and risk management policies. This study aims to improve our understanding of the hazard analysis process in the case of four remarkable flood events: March 1930, October 1940, January 1980 and November 1999. Firstly, we present the methodology used to define the remarkability score of a flood event. Then, to identify the factors leading to a remarkable flood event, we explore the main parameters of the hazard analysis process, such as the meteorological triggering conditions, the return period of the rainfall and peak discharge, as well as some additional factors (initial catchment state, flood chronology, cascade effects, etc.). The results contribute to understanding the complexity of the processes leading to flood hazard and highlight the importance for risk managers of taking additional factors into account.

  17. The resilience of neighborhood social processes: A case study of the 2011 Brisbane flood.

    PubMed

    Wickes, Rebecca; Britt, Chester; Broidy, Lisa

    2017-02-01

    Social disorganization theories position neighborhood social capital and collective efficacy as key social processes that should facilitate community resilience in the aftermath of disaster. Yet limited evidence demonstrates that these social processes are themselves resilient with some studies showing that disaster can fracture even once cohesive neighborhoods. In this paper we assess the stability of neighborhood level collective efficacy and social capital before and after a disaster. We use multilevel structural equation modeling and draw on census and longitudinal survey data collected from over 4000 residents living in 148 neighborhoods in Brisbane, Australia before and after a significant flood event. We examine what happens to social capital and collective efficacy in flooded and non-flooded neighborhoods and assess whether demographic shifts are associated with change and/or stability in these processes. We find strong evidence that these processes operate similarly across flooded and not flooded communities. Our findings also reveal significant stability for our measures of social capital across time, while collective efficacy increases post flood across all neighborhoods, but more so in flooded neighborhoods. Neighborhood demographics have limited effect on patterns of stability or change in these social processes. We discuss the theoretical and practical implications of these findings for our understanding of neighborhood resilience in the wake of disaster.

  18. Insurance against climate change and flood risk: Insurability and decision processes of insurers

    NASA Astrophysics Data System (ADS)

    Hung, Hung-Chih; Hung, Jia-Yi

    2016-04-01

    1. Background Major portions of the Asia-Pacific region is facing escalating exposure and vulnerability to climate change and flood-related extremes. This highlights an arduous challenge for public agencies to improve existing risk management strategies. Conventionally, governmental funding was majorly responsible and accountable for disaster loss compensation in the developing countries in Asia, such as Taiwan. This is often criticized as an ineffective and inefficient measure of dealing with flood risk. Flood insurance is one option within the toolkit of risk-sharing arrangement and adaptation strategy to flood risk. However, there are numerous potential barriers for insurance companies to cover flood damage, which would cause the flood risk is regarded as uninsurable. This study thus aims to examine attitudes within the insurers about the viability of flood insurance, the decision-making processes of pricing flood insurance and their determinants, as well as to examine potential solutions to encourage flood insurance. 2. Methods and data Using expected-utility theory, an insurance agent-based decision-making model was developed to examine the insurers' attitudes towards the insurability of flood risk, and to scrutinize the factors that influence their decisions on flood insurance premium-setting. This model particularly focuses on how insurers price insurance when they face either uncertainty or ambiguity about the probability and loss of a particular flood event occurring. This study considers the factors that are expected to affect insures' decisions on underwriting and pricing insurance are their risk perception, attitudes towards flood insurance, governmental measures (e.g., land-use planning, building codes, risk communication), expected probabilities and losses of devastating flooding events, as well as insurance companies' attributes. To elicit insurers' utilities about premium-setting for insurance coverage, the 'certainty equivalent,' 'probability

  19. 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

  20. The effect of pressure, isotopic (H/D) substitution, and other variables on miscibility in polymer-solvent systems. The nature of the demixing process; dynamic light scattering and small angle neutron scattering studies. Final report

    SciTech Connect

    Van Hook, W.A.

    2000-01-01

    A research program examining the effects of pressure, isotope substitution and other variables on miscibility in polymer solvent systems is described. The techniques employed included phase equilibrium measurements and dynamic light scattering and small angle neutron scattering.

  1. GIS-based flood risk model evaluated by Fuzzy Analytic Hierarchy Process (FAHP)

    NASA Astrophysics Data System (ADS)

    Sukcharoen, Tharapong; Weng, Jingnong; Teetat, Charoenkalunyuta

    2016-10-01

    Over the last 2-3 decades, the economy of many countries around the world has been developed rapidly but it was unbalanced development because of expecting on economic growth only. Meanwhile it lacked of effective planning in the use of natural resources. This can significantly induce climate change which is major cause of natural disaster. Hereby, Thailand has also suffered from natural disaster for ages. Especially, the flood which is most hazardous disaster in Thailand can annually result in the great loss of life and property, environment and economy. Since the flood management of country is inadequate efficiency. It is unable to support the flood analysis comprehensively. This paper applied Geographic Information System and Multi-Criteria Decision Making to create flood risk model at regional scale. Angthong province in Thailand was used as the study area. In practical process, Fuzzy logic technique has been used to improve specialist's assessment by implementing with Fuzzy membership because human decision is flawed under uncertainty then AHP technique was processed orderly. The hierarchy structure in this paper was categorized the spatial flood factors into two levels as following: 6 criteria (Meteorology, Geology, Topography, Hydrology, Human and Flood history) and 8 factors (Average Rainfall, Distance from Stream, Soil drainage capability, Slope, Elevation, Land use, Distance from road and Flooded area in the past). The validity of the pair-wise comparison in AHP was shown as C.R. value which indicated that the specialist judgment was reasonably consistent. FAHP computation result has shown that the first priority of criteria was Meteorology. In addition, the Rainfall was the most influencing factor for flooding. Finally, the output was displayed in thematic map of Angthong province with flood risk level processed by GIS tools. The map was classified into: High Risk, Moderate Risk and Low Risk (13.20%, 75.58%, and 11.22% of total area).

  2. Process-based selection of copula types for flood peak-volume relationships in Northwest Austria: a case study

    NASA Astrophysics Data System (ADS)

    Kohnová, Silvia; Gaál, Ladislav; Bacigál, Tomáš; Szolgay, Ján; Hlavčová, Kamila; Valent, Peter; Parajka, Juraj; Blöschl, Günter

    2016-12-01

    The case study aims at selecting optimal bivariate copula models of the relationships between flood peaks and flood volumes from a regional perspective with a particular focus on flood generation processes. Besides the traditional approach that deals with the annual maxima of flood events, the current analysis also includes all independent flood events. The target region is located in the northwest of Austria; it consists of 69 small and mid-sized catchments. On the basis of the hourly runoff data from the period 1976- 2007, independent flood events were identified and assigned to one of the following three types of flood categories: synoptic floods, flash floods and snowmelt floods. Flood events in the given catchment are considered independent when they originate from different synoptic situations. Nine commonly-used copula types were fitted to the flood peak - flood volume pairs at each site. In this step, two databases were used: i) a process-based selection of all the independent flood events (three data samples at each catchment) and ii) the annual maxima of the flood peaks and the respective flood volumes regardless of the flood processes (one data sample per catchment). The goodness-of-fit of the nine copula types was examined on a regional basis throughout all the catchments. It was concluded that (1) the copula models for the flood processes are discernible locally; (2) the Clayton copula provides an unacceptable performance for all three processes as well as in the case of the annual maxima; (3) the rejection of the other copula types depends on the flood type and the sample size; (4) there are differences in the copulas with the best fits: for synoptic and flash floods, the best performance is associated with the extreme value copulas; for snowmelt floods, the Frank copula fits the best; while in the case of the annual maxima, no firm conclusion could be made due to the number of copulas with similarly acceptable overall performances. The general

  3. Two glass transitions in miscible polymer blends?

    SciTech Connect

    Dudowicz, Jacek; Freed, Karl F.; Douglas, Jack F.

    2014-06-28

    In contrast to mixtures of two small molecule fluids, miscible binary polymer blends often exhibit two structural relaxation times and two glass transition temperatures. Qualitative explanations postulate phenomenological models of local concentration enhancements due to chain connectivity in ideal, fully miscible systems. We develop a quantitative theory that explains qualitative trends in the dynamics of real miscible polymer blends which are never ideal mixtures. The theory is a synthesis of the lattice cluster theory of blend thermodynamics, the generalized entropy theory for glass-formation in polymer materials, and the Kirkwood-Buff theory for concentration fluctuations in binary mixtures.

  4. Study of hydrocarbon miscible solvent slug injection process for improved recovery of heavy oil from Schrader Bluff Pool, Milne Point Unit, Alaska. Annual report, December 1, 1992--December 31, 1993

    SciTech Connect

    Sharma, G.D.

    1994-01-01

    The shallow Cretaceous sands of the Schrader Bluff Reservoir occur between depths of 4,000 and 4,800 feet below surface and are estimated to contain up to 1.5 billion barrels of oil in place. The field is currently under production by primary depletion. Initial production indicated that primary recovery will fall short of earlier estimates and waterflooding will have to be employed much earlier than expected. A large portion of the oil-in-place thus would still be left behind in this reservoir after primary and secondary recovery methods have been applied. Enhanced oil recovery (EOR) techniques will be needed to recover the additional portion of remaining oil in this huge reservoir and to add significant additional reserves. Slim tube displacement studies, PVT data and asphaltene precipitation studies are needed for Schrader Bluff heavy oil to define possible hydrocarbon solvent suitable for miscible solvent slug displacement process. Such studies are essential because the API gravity of the crude in Schrader Bluff reservoir varies significantly from well to well. Coreflood experiments are also needed to determine effect of solvent slug size, WAG ratio and solvent composition on the oil recovery and solvent breakthrough. A compositional reservoir simulation study will be conducted later to evaluate the complete performance of the hydrocarbon solvent slug process and to assess the feasibility of this process for improving recovery of heavy oil from Schrader Bluff reservoir. This report contains the following: reservoir description; slim tube displacement studies; and coreflood experiments.

  5. Voice-enabled Knowledge Engine using Flood Ontology and Natural Language Processing

    NASA Astrophysics Data System (ADS)

    Sermet, M. Y.; Demir, I.; Krajewski, W. F.

    2015-12-01

    The Iowa Flood Information System (IFIS) is a web-based platform developed by the Iowa Flood Center (IFC) to provide access to flood inundation maps, real-time flood conditions, flood forecasts, flood-related data, information and interactive visualizations for communities in Iowa. The IFIS is designed for use by general public, often people with no domain knowledge and limited general science background. To improve effective communication with such audience, we have introduced a voice-enabled knowledge engine on flood related issues in IFIS. Instead of navigating within many features and interfaces of the information system and web-based sources, the system provides dynamic computations based on a collection of built-in data, analysis, and methods. The IFIS Knowledge Engine connects to real-time stream gauges, in-house data sources, analysis and visualization tools to answer natural language questions. Our goal is the systematization of data and modeling results on flood related issues in Iowa, and to provide an interface for definitive answers to factual queries. The goal of the knowledge engine is to make all flood related knowledge in Iowa easily accessible to everyone, and support voice-enabled natural language input. We aim to integrate and curate all flood related data, implement analytical and visualization tools, and make it possible to compute answers from questions. The IFIS explicitly implements analytical methods and models, as algorithms, and curates all flood related data and resources so that all these resources are computable. The IFIS Knowledge Engine computes the answer by deriving it from its computational knowledge base. The knowledge engine processes the statement, access data warehouse, run complex database queries on the server-side and return outputs in various formats. This presentation provides an overview of IFIS Knowledge Engine, its unique information interface and functionality as an educational tool, and discusses the future plans

  6. Viscous fingering with partial miscible fluids

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

    When a less viscous fluid displaces a more viscous fluid, the contrast in viscosity destabilizes the interface between the two fluids, leading to the formation of fingers. Studies of viscous fingering have focused on fluids that are either fully miscible or perfectly immiscible. In practice, however, the miscibility of two fluids can change appreciably with temperature and pressure, and often falls into the case of partial miscibility, where two fluids have limited solubility in each other. Following our recent work for miscible (Jha et al., PRL 2011, 2013) and immiscible systems (Cueto-Felgueroso and Juanes, PRL 2012, JFM 2014), here we propose a phase-field model for fluid-fluid displacements in a Hele-Shaw cell, when the two fluids have limited (but nonzero) solubility in one another. Partial miscibility is characterized through the design of thermodynamic free energy of the two-fluid system. We elucidate the key dimensionless groups that control the behavior of the system. We present high-resolution numerical simulations of the model applied to the viscous fingering problem. On one hand, we demonstrate the effect of partial miscibility on the hydrodynamic instability. On the other, we elucidate the role of the degree of fingering on the rate of mutual fluid dissolution.

  7. An integrated process for the production of platform chemicals and diesel miscible fuels by acid-catalyzed hydrolysis and downstream upgrading of the acid hydrolysis residues with thermal and catalytic pyrolysis.

    PubMed

    Girisuta, Buana; Kalogiannis, Konstantinos G; Dussan, Karla; Leahy, James J; Hayes, Michael H B; Stefanidis, Stylianos D; Michailof, Chrysa M; Lappas, Angelos A

    2012-12-01

    This study evaluates an integrated process for the production of platform chemicals and diesel miscible biofuels. An energy crop (Miscanthus) was treated hydrothermally to produce levulinic acid (LA). Temperatures ranging between 150 and 200 °C, sulfuric acid concentrations 1-5 wt.% and treatment times 1-12 h were applied to give different combined severity factors. Temperatures of 175 and 200 °C and acid concentration of 5 wt.% were found to be necessary to achieve good yield (17 wt.%) and selectivities of LA while treatment time did not have an effect. The acid hydrolysis residues were characterized for their elemental, cellulose, hemicellulose and lignin contents, and then tested in a small-scale pyrolyzer using silica sand and a commercial ZSM-5 catalyst. Milder pretreatment yielded more oil (43 wt.%) and oil O(2) (37%) while harsher pretreatment and catalysis led to more coke production (up to 58 wt.%), less oil (12 wt.%) and less oil O(2) (18 wt.%).

  8. A regional look at the selection of a process-oriented model for flood peak/volume relationships

    NASA Astrophysics Data System (ADS)

    Szolgay, Ján; Gaál, Ladislav; Bacigál, Tomáš; Kohnová, Silvia; Hlavčová, Kamila; Výleta, Roman; Blöschl, Günter

    2016-05-01

    Recent research on the bivariate flood peak/volume frequency analysis has mainly focused on the statistical aspects of the use of various copula models. The interplay of climatic and catchment processes in discriminating among these models has attracted less interest. In the paper we analyse the influence of climatic and hydrological controls on flood peak and volume relationships and their models, which are based on the concept of comparative hydrology in the catchments of a selected region in Austria. Independent flood events have been isolated and assigned to one of the three types of flood processes: synoptic floods, flash floods and snowmelt floods. First, empirical copulas are regionally compared in order to verify whether any flood processes are discernible in terms of the corresponding bivariate flood-peak relationships. Next the types of copulas, which are frequently used in hydrology are fitted, and their goodness-of-fit is examined in a regional scope. The spatial similarity of copulas and their rejection rate, depending on the flood type, region, and sample size are examined, too. In particular, the most remarkable difference is observed between flash floods and the other two types of flood. It is concluded that treating flood processes separately in such an analysis is beneficial, both hydrologically and statistically, since flood processes and the relationships associated with them are discernible both locally and regionally in the pilot region. However, uncertainties inherent in the copula-based bivariate frequency analysis itself (caused, among others, also by the relatively small sample sizes for consistent copula model selection, upper tail dependence characterization and reliable predictions) may not be overcome in the scope of such a regional comparative analysis.

  9. 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.

  10. Post waterflood CO{sub 2} miscible flood in light oil, fluvial - dominated deltaic reservoirs. Technical progress report, 4th quarter, fiscal year 1994, July 1, 1994--September 30, 1994

    SciTech Connect

    Not Available

    1994-10-15

    Production from the Port Neches project has reached a new high of 500 BOPD, as shown. Production from several wells has improved after changing WAGer and CO{sub 2} injection patterns. The WAG process appears to be effective in FDD reservoirs. The WAT process has improved the oil production rates and simultaneously decreased the CO{sub 2} production rates from wells with high GOR. Material balance calculations indicate that the reservoir pressure remained relatively flat, and a new BHP will be taken this month to verify the calculations. Total CO{sub 2} injection is averaging about 9.5 MMCFD, including 3.9 MMCFD purchased from Cardox, as shown, and the balance is recycled from the producing wells. Over 50% of the gas was produced from one well, Khun No. 33. A CO{sub 2} injection line was installed to huff-puff well Khun No. 6 that did not respond yet to CO{sub 2} injection in well Khun No. 17. After injecting a limited CO{sub 2} volume in well Khun No. 6, this will be followed by a short shut-in period, then the well will be placed on production.

  11. Effects of multiscale rainfall variability on flood frequency: Comparative multisite analysis of dominant runoff processes

    NASA Astrophysics Data System (ADS)

    Samuel, Jos M.; Sivapalan, Murugesu

    2008-09-01

    We present results of a comparative modeling analysis of the effects of multiscale rainfall variability (within-event, between-event, seasonal, interannual, and interdecadal) on estimated flood frequency curves for three catchments located in Perth, Newcastle, and Darwin, Australia. The analysis is performed using the derived distribution approach by combining long-term rainfall time series generated by a stochastic rainfall model with a continuous rainfall-runoff flood model that is able to generate runoff variability over a multiplicity of timescales. Similarities and differences of the flood frequency curves (FFCs) in these rather diverse catchments are then interpreted on the basis of differences in the dominant runoff generation processes. In Newcastle, annual maximum flood peaks are caused by saturation excess overland flow over the entire range of annual exceedance probabilities (AEPs) or return periods. On the other hand, in Darwin, the shape of the FFC is determined strongly by seasonal climatic variability, which, in combination with deep soils, leads to a switch of dominant runoff mechanisms contributing to annual maximum flood peaks, from subsurface stormflow at high AEPs (low return periods) to saturation excess overland flow at low AEPs (high return periods). This leads to FFCs exhibiting a consistent break in slope in the Darwin catchment but not so in Newcastle. On the other hand, the FFCs in Perth are affected by both seasonality and long-term climate variability and produce a variety of shapes depending on the relative strengths of these climatic controls. Because of the fact that in Perth and Darwin the shapes of the flood frequency curves depend on a possible switch of the dominant runoff generation mechanisms with increasing return period, uncertainty in hydrological model parameters relating to landscape properties contributes significantly to the uncertainty in the flood frequency curves. This uncertainty is much less pronounced in Newcastle

  12. Quantifying the effect of sea level rise and flood defence - a point process perspective on coastal flood damage

    NASA Astrophysics Data System (ADS)

    Boettle, M.; Rybski, D.; Kropp, J. P.

    2016-02-01

    In contrast to recent advances in projecting sea levels, estimations about the economic impact of sea level rise are vague. Nonetheless, they are of great importance for policy making with regard to adaptation and greenhouse-gas mitigation. Since the damage is mainly caused by extreme events, we propose a stochastic framework to estimate the monetary losses from coastal floods in a confined region. For this purpose, we follow a Peak-over-Threshold approach employing a Poisson point process and the Generalised Pareto Distribution. By considering the effect of sea level rise as well as potential adaptation scenarios on the involved parameters, we are able to study the development of the annual damage. An application to the city of Copenhagen shows that a doubling of losses can be expected from a mean sea level increase of only 11 cm. In general, we find that for varying parameters the expected losses can be well approximated by one of three analytical expressions depending on the extreme value parameters. These findings reveal the complex interplay of the involved parameters and allow conclusions of fundamental relevance. For instance, we show that the damage typically increases faster than the sea level rise itself. This in turn can be of great importance for the assessment of sea level rise impacts on the global scale. Our results are accompanied by an assessment of uncertainty, which reflects the stochastic nature of extreme events. While the absolute value of uncertainty about the flood damage increases with rising mean sea levels, we find that it decreases in relation to the expected damage.

  13. Quantifying the effect of sea level rise and flood defence - apoint process perspective on coastal flood damage

    NASA Astrophysics Data System (ADS)

    Boettle, M.; Rybski, D.; Kropp, J. P.

    2015-10-01

    In contrast to recent advances in projecting sea levels, estimations about the economic impact of sea level rise are vague. Nonetheless, they are of great importance for policy making with regard to adaptation and greenhouse-gas mitigation. Since the damage is mainly caused by extreme events, we propose a stochastic framework to estimate the monetary losses from coastal floods in a confined region. For this purpose, we follow a Peak-over-Threshold approach employing a Poisson point process and the Generalised Pareto Distribution. By considering the effect of sea level rise as well as potential adaptation scenarios on the involved parameters, we are able to study the development of the annual damage. An application to the city of Copenhagen shows that a doubling of losses can be expected from a mean sea level increase of only 11 cm. In general, we find that for varying parameters the expected losses can be well approximated by one of three analytical expressions depending on the extreme value parameters. These findings reveal the complex interplay of the involved parameters and allow conclusions of fundamental relevance. For instance, we show that the damage always increases faster than the sea level rise itself. This in turn can be of great importance for the assessment of sea level rise impacts on the global scale. Our results are accompanied by an assessment of uncertainty, which reflects the stochastic nature of extreme events. While the uncertainty of flood damage increases with rising sea levels, we find that the error of our estimations in relation to the expected damage decreases.

  14. Towards a generalized catchment flood processes simulation system with distributed hydrological model

    NASA Astrophysics Data System (ADS)

    Chen, Y.

    2015-12-01

    High resolution distributed hydrological model is regarded as to have the potential to finely simulate the catchment hydrological processes, but challenges still exist. This paper, presented a generalized catchment flood processes simulation system with Liuxihe Model, a physically-based distributed hydrological model proposed mainly for catchment flood forecasting, which is a process-based hydrological model. In this system, several cutting edge technologies have been employed, such as the supercomputing technology, PSO algorithm for parameter optimization, cloud computation, GIS and software engineering, and it is deployed on a high performance computer with free public accesses. The model structure setting up data used in this system is the open access database, so it could be used for catchments world widely. With the application of parallel computation algorithm, the model spatial resolution could be as fine as up to 100 m grid, while maintaining high computation efficiency, and could be used in large scale catchments. With the utilization of parameter optimization method, the model performance cold be improved largely. The flood events of several catchments in southern China with different drainage sizes have been simulated by this system, and the results show that this system has strong capability in simulating catchment flood events even in large river basins.

  15. Processes and Geomorphological Impacts of an Extreme Flash Flood Event in SE Spain

    NASA Astrophysics Data System (ADS)

    Hooke, J.

    2015-12-01

    A major flash flood event took place on 28 September, 2012 in SE Spain, resulting in 10 fatalities and much damage to infrastructure regionally. The flood affected long-term monitoring sites in two catchments in which morphological changes and flow dynamics of these ephemeral channels were being measured. Thus detailed data on channel state prior to the flood were available. The flood event in the Nogalte catchment was extreme in its peak flow, rate of rise and unit runoff. The catchment has steep relief and much bare soil under almond groves, resulting in high sediment supply. The channel is confined in places, but mostly wide and braided, composed of loose gravel and occupying much of the valley floor. Flow was spatially continuous, with high connectivity throughout the catchment. The flood effects were net depositional in the monitored sites, with massive sedimentation on the channel bars. Vegetation was destroyed. Bank erosion and destruction of embankments took place in some locations. Hydraulic calculations indicate very high velocities, stream power and Froude numbers. Modelling and field evidence demonstrate extremely high sediment competence and sediment loadings. The influence of the event dynamics on processes and net outcomes is discussed. The impacts are compared with other events in this and neighbouring catchments. Overall, the event in the Nogalte did not alter the morphology markedly in spite of its extreme characteristics. It is suggested that these valley floors are adapted to this type of flash flood but that flows of such force and magnitude need to be allowed for in management in such an environment.

  16. Optical data processing and projected applications of the ERTS-1 imagery covering the 1973 Mississippi River Valley floods

    USGS Publications Warehouse

    Deutsch, Morris; Ruggles, Fred

    1974-01-01

    Flooding along the Mississippi River and some of its tributaries was detected by the multispectral scanner (MSS) on the Earth Resources Technology Satellite (ERTS-1) on at least three orbits during the spring of 1973. The ERTS data provided the first opportunity for mapping the regional extent of flooding at the time of the imagery. Special optical data processing techniques were used to produce a variety of multispectral color composites enhancing flood-plain details. One of these, a 2-color composite of near infrared bands 6 and 7, was enlarged and registered to 1:250,000-scale topographic maps and used as the basis for preparation of flood image maps. Two specially filtered 3-color composites of MSS bands 5, 6, and 7 and 4, 5, and 7 were prepared to aid in the interpretation of the data. The extent of the flooding was vividly depicted on a single image by 2-color temporal composites produced on the additive-color viewer using band 7 flood data superimposed on pre-flood band 7 images. On May 24, when the floodwaters at St. Louis receded to bankfull stage, imagery was again obtained by ERTS. Analysis of temporal data composites of the pre-flood and post-flood band 7 images indicate that changes in surface reflectance characteristics caused by the flooding can be delineated, thus making it possible to map the overall area flooded without the necessity of a real-time system to track and image the peak flood waves. Regional planning and disaster relief agencies such as the Corps of Engineers, Office of Emergency Preparedness, Soil Conservation Service, interstate river basin commissions and state agencies, as well as private lending and insurance institutions, have indicated strong potential applications for ERTS image-maps of flood-prone areas.

  17. Miscibility of Itraconazole-Hydroxypropyl Methylcellulose Blends: Insights with High Resolution Analytical Methodologies.

    PubMed

    Purohit, Hitesh S; Taylor, Lynne S

    2015-12-07

    Drug-polymer miscibility is considered to be a prerequisite to achieve an optimally performing amorphous solid dispersion (ASD). Unfortunately, it can be challenging to evaluate drug-polymer miscibility experimentally. The aim of this study was to investigate the miscibility of ASDs of itraconazole (ITZ) and hydroxypropyl methylcellulose (HPMC) using a variety of analytical approaches. The phase behavior of ITZ-HPMC films prepared by solvent evaporation was studied before and after heating. Conventional methodology for miscibility determination, that is, differential scanning calorimetry (DSC), was used in conjunction with emerging analytical techniques, such as fluorescence spectroscopy, fluorescence imaging, and atomic force microscopy coupled with nanoscale infrared spectroscopy and nanothermal analysis (AFM-nanoIR-nanoTA). DSC results showed a single glass transition event for systems with 10% to 50% drug loading, suggesting that the ASDs were miscible, whereas phase separation was observed for all of the films based on the other techniques. The AFM-coupled techniques indicated that the phase separation occurred at the submicron scale. When the films were heated, it was observed that the ASD components underwent mixing. The results provide new insights into the phase behavior of itraconazole-HPMC dispersions and suggest that the emerging analytical techniques discussed herein are promising for the characterization of miscibility and microstructure in drug-polymer systems. The observed differences in the phase behavior in films prepared by solvent evaporation before and after heating also have implications for processing routes and suggest that spray drying/solvent evaporation and hot melt extrusion/melt mixing can result in ASDs with varying extent of miscibility between the drug and the polymer.

  18. A FRAMEWORK TO DESIGN AND OPTIMIZE CHEMICAL FLOODING PROCESSES

    SciTech Connect

    Mojdeh Delshad; Gary A. Pope; Kamy Sepehrnoori

    2005-07-01

    The goal of this proposed research is to provide an efficient and user friendly simulation framework for screening and optimizing chemical/microbial enhanced oil recovery processes. The framework will include (1) a user friendly interface to identify the variables that have the most impact on oil recovery using the concept of experimental design and response surface maps, (2) UTCHEM reservoir simulator to perform the numerical simulations, and (3) an economic model that automatically imports the simulation production data to evaluate the profitability of a particular design. Such a reservoir simulation framework is not currently available to the oil industry. The objectives of Task 1 are to develop three primary modules representing reservoir, chemical, and well data. The modules will be interfaced with an already available experimental design model. The objective of the Task 2 is to incorporate UTCHEM reservoir simulator and the modules with the strategic variables and developing the response surface maps to identify the significant variables from each module. The objective of the Task 3 is to develop the economic model designed specifically for the chemical processes targeted in this proposal and interface the economic model with UTCHEM production output. Task 4 is on the validation of the framework and performing simulations of oil reservoirs to screen, design and optimize the chemical processes.

  19. A Framework to Design and Optimize Chemical Flooding Processes

    SciTech Connect

    Mojdeh Delshad; Gary A. Pope; Kamy Sepehrnoori

    2006-08-31

    The goal of this proposed research is to provide an efficient and user friendly simulation framework for screening and optimizing chemical/microbial enhanced oil recovery processes. The framework will include (1) a user friendly interface to identify the variables that have the most impact on oil recovery using the concept of experimental design and response surface maps, (2) UTCHEM reservoir simulator to perform the numerical simulations, and (3) an economic model that automatically imports the simulation production data to evaluate the profitability of a particular design. Such a reservoir simulation framework is not currently available to the oil industry. The objectives of Task 1 are to develop three primary modules representing reservoir, chemical, and well data. The modules will be interfaced with an already available experimental design model. The objective of the Task 2 is to incorporate UTCHEM reservoir simulator and the modules with the strategic variables and developing the response surface maps to identify the significant variables from each module. The objective of the Task 3 is to develop the economic model designed specifically for the chemical processes targeted in this proposal and interface the economic model with UTCHEM production output. Task 4 is on the validation of the framework and performing simulations of oil reservoirs to screen, design and optimize the chemical processes.

  20. A FRAMEWORK TO DESIGN AND OPTIMIZE CHEMICAL FLOODING PROCESSES

    SciTech Connect

    Mojdeh Delshad; Gary A. Pope; Kamy Sepehrnoori

    2004-11-01

    The goal of this proposed research is to provide an efficient and user friendly simulation framework for screening and optimizing chemical/microbial enhanced oil recovery processes. The framework will include (1) a user friendly interface to identify the variables that have the most impact on oil recovery using the concept of experimental design and response surface maps, (2) UTCHEM reservoir simulator to perform the numerical simulations, and (3) an economic model that automatically imports the simulation production data to evaluate the profitability of a particular design. Such a reservoir simulation framework is not currently available to the oil industry. The objectives of Task 1 are to develop three primary modules representing reservoir, chemical, and well data. The modules will be interfaced with an already available experimental design model. The objective of the Task 2 is to incorporate UTCHEM reservoir simulator and the modules with the strategic variables and developing the response surface maps to identify the significant variables from each module. The objective of the Task 3 is to develop the economic model designed specifically for the chemical processes targeted in this proposal and interface the economic model with UTCHEM production output. Task 4 is on the validation of the framework and performing simulations of oil reservoirs to screen, design and optimize the chemical processes.

  1. Floods and Flash Flooding

    MedlinePlus

    Floods and flash flooding Now is the time to determine your area’s flood risk. If you are not sure whether you ... If you are in a floodplain, consider buying flood insurance. Do not drive around barricades. If your ...

  2. State-of-the-art review of nitrogen and flue gas flooding in enhanced oil recovery. Final report

    SciTech Connect

    Anada, H.R.

    1980-12-01

    This report provides a review of technical publications and patents in the field of nitrogen and flue gas flooding in Enhanced Oil Recovery (EOR). The physical and chemical characteristics of nitrogen and flue gas are provided with some comparisons with CO/sub 2/ related to EOR operations. Experimental research and field based activities using nitrogen and flue gas are briefly summarized. Cost data for generation of nitrogen and flue gases are provided. Nitrogen and flue gas costs are approximately one third to one half that of CO/sub 2/. The low cost of production and its non-corrosive nature are advantages of using nitrogen, whereas the higher miscibility pressure requirement is a disadvantage. Nitrogen flooding does not work well with low API gravity crudes. Miscible displacement with nitrogen seems promising for oils containing solution gas. Flue gas flooding can be applied to low API gravity crude reservoirs. However, flue gas flooding creates operating problems due to its corrosive nature. The report provides a discussion on process and reservoir parameters that affect nitrogen and/or flue gas flooding in EOR. A bibliography of related literature is provided in the appendices.

  3. 4-D High-Resolution Seismic Reflection Monitoring of Miscible CO2 Injected into a Carbonate Reservoir

    SciTech Connect

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

    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 limestones 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.

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

    SciTech Connect

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

    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-Kansas 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.

  5. 4-D High-Resolution Seismic Reflection Monitoring of Miscible CO2 Injected into a Carbonate Reservoir

    SciTech Connect

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

    2006-08-31

    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 in an attempt 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-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.

  6. Coupling glacial lake impact, dam breach, and flood processes: A modeling perspective

    NASA Astrophysics Data System (ADS)

    Worni, Raphael; Huggel, Christian; Clague, John J.; Schaub, Yvonne; Stoffel, Markus

    2014-11-01

    Glacial lake outburst floods (GLOFs) are highly mobile mixtures of water and sediment that occur suddenly and are capable of traveling tens to hundreds of kilometers with peak discharges and volumes several orders of magnitude larger than those of normal floods. They travel along existing river channels, in some instances into populated downstream regions, and thus pose a risk to people and infrastructure. Many recent events involve process chains, such as mass movements impacting glacial lakes and triggering dam breaches with subsequent outburst floods. A concern is that effects of climate change and associated increased instability of high mountain slopes may exacerbate such process chains and associated extreme flows. Modeling tools can be used to assess the hazard of potential future GLOFs, and process modeling can provide insights into complex processes that are difficult to observe in nature. A number of numerical models have been developed and applied to simulate different types of extreme flows, but such modeling faces challenges stemming from a lack of process understanding and difficulties in measuring extreme flows for calibration purposes. Here we review the state of knowledge of key aspects of modeling GLOFs, with a focus on process cascades. Analysis and simulation of the onset, propagation, and potential impact of GLOFs are based on illustrative case studies. Numerical models are presently available for simulating impact waves in lakes, dam failures, and flow propagation but have been used only to a limited extent for integrated simulations of process cascades. We present a spectrum of case studies from Patagonia, the European Alps, central Asia, and the Himalayas in which we simulate single processes and process chains of past and potential future events. We conclude that process understanding and process chain modeling need to be strengthened and that research efforts should focus on a more integrative treatment of processes in numerical models.

  7. Viscous fingering with partially miscible fluids

    NASA Astrophysics Data System (ADS)

    Fu, X.; Cueto-Felgueroso, L.; Juanes, R.

    2015-12-01

    When a less viscous fluid displaces a more viscous fluid, the contrast in viscosity destabilizes the interface between the two fluids, leading to the formation of fingers. Experimental and numerical studies of viscous fingering have focused on fluids that are either fully miscible (e.g. water and glycerol) or perfectly immiscible (e.g. water and oil). In practice, however, the miscibility of two fluids can change appreciably with temperature and pressure, and often falls into the case of partial miscibility, where two fluids have limited solubility in each other (e.g. CO2 and water). Following our recent work for miscible systems (Jha et al., PRL 2011, 2013) and immiscible systems (Cueto-Felgueroso and Juanes, PRL 2012, JFM 2014), here we propose a phase-field model for fluid-fluid displacements in a porous medium, when the two fluids have limited (but nonzero) solubility in one another. In our model, partial miscibility is characterized through the design of the thermodynamic free energy of the two-fluid system. We express the model in dimensionless form and elucidate the key dimensionless groups that control the behavior of the system. We present high-resolution numerical simulations of the model applied to the viscous fingering problem. On one hand, we demonstrate the effect of partial miscibility on the hydrodynamic instability. On the other, we elucidate the role of the degree of fingering on the rate of mutual fluid dissolution. Figure caption: final snapshots in simulations of viscous fingering with a two-fluid system mimicking that of CO2 and water. The colormap corresponds to the concentration of CO2. A band of less viscous gas phase rich in CO2 (red) displaces through the more viscous liquid phase that is undersaturated with CO2 (blue). At the fluid interface, an exchange of CO2 occurs as a result of local chemical potentials that drives the system towards thermodynamic equilibrium. This results in a shrinkage of gas phase as well as a local increase in

  8. Influence of seismic processes and volcanic activity on the formation of disastrous floods

    NASA Astrophysics Data System (ADS)

    Trifonov, Dmitriy

    2014-05-01

    Traditionally, the main cause of catastrophic floods are considered prolonged heavy rains, which lead to over-saturation of soil moisture and the deposition of precipitation on the surface of the earth. And at the same time there is reason to believe that precipitation cannot be the main cause of floods. Firstly, we observe a catastrophic floods not in every case of heavy precipitation: moreover, a direct correlation between precipitation intensity and scale of the flooding is not detected. Secondly, a simple calculation shows that the quantity of water, that drops down to the ground with torrential rains, are insufficient to cover the earth's surface such layer of water, where we can talk about the flood (especially catastrophic). In particular, the intensity of normal not tropical rainfall does not exceed 60 mm per hour. Then such a downpour would have to go continuously for at least two days in a row, to cause flooding of a height of 3 m provided a complete impenetrability of the earth's surface. In reality, however, such showers last no more than half an hour. Thus, it can be argued that the source of water for catastrophic floods fed by ground water, the volume of which is comparable with the volume of all surface water on Earth [1]. Classic examples of surface and groundwater interactions are, on the one hand, springs and artesian wells, and on the other hand, the phenomenon of absorption of precipitation by soil. In normal conditions underground water is moving by aquifers, penetrating through the pores and cracks in rocks in the conditions of nonstationary/unsteady filtration, forming a 3D network of underground channels in different directions (horizontal, vertical, inclined), including the so-called underground lakes - water basins in underground cavities. Especially strongly these processes are shown in the fractured and karst rocks. It is also important that the movement of water obeys the laws of hydrostatics and hydrodynamics in terms of specific

  9. Unmanned Aerial Vehicle Systems for Remote Estimation of Flooded Areas Based on Complex Image Processing

    PubMed Central

    Popescu, Dan; Ichim, Loretta; Stoican, Florin

    2017-01-01

    Floods are natural disasters which cause the most economic damage at the global level. Therefore, flood monitoring and damage estimation are very important for the population, authorities and insurance companies. The paper proposes an original solution, based on a hybrid network and complex image processing, to this problem. As first novelty, a multilevel system, with two components, terrestrial and aerial, was proposed and designed by the authors as support for image acquisition from a delimited region. The terrestrial component contains a Ground Control Station, as a coordinator at distance, which communicates via the internet with more Ground Data Terminals, as a fixed nodes network for data acquisition and communication. The aerial component contains mobile nodes—fixed wing type UAVs. In order to evaluate flood damage, two tasks must be accomplished by the network: area coverage and image processing. The second novelty of the paper consists of texture analysis in a deep neural network, taking into account new criteria for feature selection and patch classification. Color and spatial information extracted from chromatic co-occurrence matrix and mass fractal dimension were used as well. Finally, the experimental results in a real mission demonstrate the validity of the proposed methodologies and the performances of the algorithms. PMID:28241479

  10. Unmanned Aerial Vehicle Systems for Remote Estimation of Flooded Areas Based on Complex Image Processing.

    PubMed

    Popescu, Dan; Ichim, Loretta; Stoican, Florin

    2017-02-23

    Floods are natural disasters which cause the most economic damage at the global level. Therefore, flood monitoring and damage estimation are very important for the population, authorities and insurance companies. The paper proposes an original solution, based on a hybrid network and complex image processing, to this problem. As first novelty, a multilevel system, with two components, terrestrial and aerial, was proposed and designed by the authors as support for image acquisition from a delimited region. The terrestrial component contains a Ground Control Station, as a coordinator at distance, which communicates via the internet with more Ground Data Terminals, as a fixed nodes network for data acquisition and communication. The aerial component contains mobile nodes-fixed wing type UAVs. In order to evaluate flood damage, two tasks must be accomplished by the network: area coverage and image processing. The second novelty of the paper consists of texture analysis in a deep neural network, taking into account new criteria for feature selection and patch classification. Color and spatial information extracted from chromatic co-occurrence matrix and mass fractal dimension were used as well. Finally, the experimental results in a real mission demonstrate the validity of the proposed methodologies and the performances of the algorithms.

  11. A review of atmospheric and land surface processes with emphasis on flood generation in the Southern Himalayan rivers.

    PubMed

    Dimri, A P; Thayyen, R J; Kibler, K; Stanton, A; Jain, S K; Tullos, D; Singh, V P

    2016-06-15

    Floods in the southern rim of the Indian Himalayas are a major cause of loss of life, property, crops, infrastructure, etc. They have long term socio-economic impacts on the habitat living along/across the Himalayas. In the recent decade extreme precipitation events have led to numerous flash floods in and around the Himalayan region. Sporadic case-based studies have tried to explain the mechanisms causing the floods. However, in some of the cases, the causative mechanisms have been elusive. Various types of flood events have been debated at different spatial and temporal scales. The present study provides an overview of mechanisms that lead to floods in and around the southern rim of the Indian Himalayas. Atmospheric processes, landuse interaction, and glacier-related outbreaks are considered in the overview.

  12. How Pure Components Control Polymer Blend Miscibility

    NASA Astrophysics Data System (ADS)

    White, Ronald; Lipson, Jane; Higgins, Julia

    2012-02-01

    We present insight into some intriguing relationships revealed by our recent studies of polymer mixture miscibility. Applying our simple lattice-based equation of state, we discuss some of the patterns observed over a sample of experimental blends. We focus on the question of how much key information can one determine from a knowledge of just the pure components only, and further, on the role of separate enthalpic and entropic contributions to the miscibility behavior. One interesting correlation connects the value of the difference in pure component energetic parameters with that of the mixed segment interactions, suggesting new possibilities for predictive modeling. We also show how in some cases these two parameter groupings act as separate controls determining the entropy and enthalpy of mixing. Also discussed are the different patterns exhibited for UCST-type and LCST-type blends, these being revealed in some cases by simple examination of the underlying microscopic parameters.

  13. Spatial Analysis in Determination Of Flood Prone Areas Using Geographic Information System and Analytical Hierarchy Process at Sungai Sembrong's Catchment

    NASA Astrophysics Data System (ADS)

    Bukari, S. M.; Ahmad, M. A.; Wai, T. L.; Kaamin, M.; Alimin, N.

    2016-07-01

    Floods that struck Johor state in 2006 and 2007 and the East Coastal in 2014 have triggered a greatly impact to the flood management here in Malaysia. Accordingly, this study conducted to determine potential areas of flooding, especially in Batu Pahat district since it faces terrifying experienced with heavy flood. This objective is archived by using the application of Geographic Information Systems (GIS) on study area of flood risk location at the watershed area of Sungai Sembrong. GIS functions as spatial analysis is capable to produce new information based on analysis of data stored in the system. Meanwhile the Analytical Hierarchy Process (AHP) was used as a method for setting up in decision making concerning the existing data. By using AHP method, preparation and position of the criteria and parameters required in GIS are neater and easier to analyze. Through this study, a flood prone area in the watershed of Sungai Sembrong was identified with the help of GIS and AHP. Analysis was conducted to test two different cell sizes, which are 30 and 5. The analysis of flood prone areas were tested on both cell sizes with two different water levels and the results of the analysis were displayed by GIS. Therefore, the use of AHP and GIS are effective and able to determine the potential flood plain areas in the watershed area of Sungai Sembrong.

  14. Dynamics of miscible displacements in round tubes

    SciTech Connect

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

    1995-12-31

    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.

  15. 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.

  16. Oil recovery by nitrogen flooding. Final report

    SciTech Connect

    Ronde, H.; Hagoort, J.

    1992-03-01

    The general objective of the project is the Establishment of technical and economic design criteria and evaluation tools for oil and condensate recovery by Nitrogen Injection. The main objective has been divided into the following specific objectives: Determination of the effect of oil composition on the oil recovery; Investigation of the pros and cons of slim-tube experiments as a tool for the design and evaluation of nitrogen flooding; Measurement and calculation of the minimum miscibility pressures (MMP) for nitrogen flooding.

  17. Projecting nuisance flooding in a warming climate using generalized linear models and Gaussian processes

    NASA Astrophysics Data System (ADS)

    Vandenberg-Rodes, Alexander; Moftakhari, Hamed R.; AghaKouchak, Amir; Shahbaba, Babak; Sanders, Brett F.; Matthew, Richard A.

    2016-11-01

    Nuisance flooding corresponds to minor and frequent flood events that have significant socioeconomic and public health impacts on coastal communities. Yearly averaged local mean sea level can be used as proxy to statistically predict the impacts of sea level rise (SLR) on the frequency of nuisance floods (NFs). In this study, we use generalized linear models (GLM) and Gaussian Process (GP) models combined to (i) estimate the frequency of NF associated with the change in mean sea level, and (ii) quantify the associated uncertainties via a novel and statistically robust approach. We calibrate our models to the water level data from 18 tide gauges along the coasts of United States, and after validation, we estimate the frequency of NF associated with the SLR projections in year 2030 (under RCPs 2.6 and 8.5), along with their 90% bands, at each gauge. The historical NF-SLR data are very noisy, and show large changes in variability (heteroscedasticity) with SLR. Prior models in the literature do not properly account for the observed heteroscedasticity, and thus their projected uncertainties are highly suspect. Among the models used in this study, the Negative Binomial Distribution GLM with GP best characterizes the uncertainties associated with NF estimates; on validation data ≈93% of the points fall within the 90% credible limit, showing our approach to be a robust model for uncertainty quantification.

  18. Molecular Driving Forces behind the Tetrahydrofuran-Water Miscibility Gap.

    PubMed

    Smith, Micholas Dean; Mostofian, Barmak; Petridis, Loukas; Cheng, Xiaolin; Smith, Jeremy C

    2016-02-04

    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 water is significantly altered and the second virial coefficients (pair-interaction strengths) show parabolic-like behavior. Overall, 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.

  19. 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

  20. Molecular driving forces behind the tetrahydrofuran–water miscibility gap

    SciTech Connect

    Smith, Micholas Dean; Mostofian, Barmak; Petridis, Loukas; Cheng, Xiaolin; Smith, Jeremy C.

    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 water 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.

  1. Miscibility and dynamical properties of cellulose acetate/plasticizer systems.

    PubMed

    Bao, Cong Yu; Long, Didier R; Vergelati, Caroll

    2015-02-13

    Due to its biodegradability and renewability, a great interest has been devoted to investigating cellulose acetate in order to expand its potential applications. In addition, secondary cellulose acetate (CDA) could also be considered as a model system for strongly polar polymer system. The dynamical behavior of CDA is supposed to be governed by H-bonding and dipolar interaction network. Due to their high glass transition temperature, cellulose acetate-based systems are processed when blended with plasticizers. It is thus of utmost importance to study the miscibility and plasticizing effects of various molecules. We prepared CDA films via solvent casting method with diethyl phthalate as the plasticizer. Miscibility diagrams were established by calorimetry and thermo-mechanical (DMTA) experiments. Dynamical properties were analyzed by DMTA and broadband dielectric spectroscopy. We could identify the α-relaxation of these CDA-plasticizer systems in the frequency range from 0.06 Hz to 10(6)Hz, which allowed for describing the dynamics in the so-called Williams-Landel-Ferry/Vogel-Fulcher-Tammann regime.

  2. Flood hazards analysis based on changes of hydrodynamic processes in fluvial systems of Sao Paulo, Brazil.

    NASA Astrophysics Data System (ADS)

    Simas, Iury; Rodrigues, Cleide

    2016-04-01

    The metropolis of Sao Paulo, with its 7940 Km² and over 20 million inhabitants, is increasingly being consolidated with disregard for the dynamics of its fluvial systems and natural limitations imposed by fluvial terraces, floodplains and slopes. Events such as floods and flash floods became particularly persistent mainly in socially and environmentally vulnerable areas. The Aricanduva River basin was selected as the ideal area for the development of the flood hazard analysis since it presents the main geological and geomorphological features found in the urban site. According to studies carried out by Anthropic Geomorphology approach in São Paulo, to study this phenomenon is necessary to take into account the original hydromorphological systems and its functional conditions, as well as in which dimensions the Anthropic factor changes the balance between the main variables of surface processes. Considering those principles, an alternative model of geographical data was proposed and enabled to identify the role of different driving forces in terms of spatial conditioning of certain flood events. Spatial relationships between different variables, such as anthropogenic and original morphology, were analyzed for that purpose in addition to climate data. The surface hydrodynamic tendency spatial model conceived for this study takes as key variables: 1- The land use present at the observed date combined with the predominant lithological group, represented by a value ranging 0-100, based on indexes of the National Soil Conservation Service (NSCS-USA) and the Hydraulic Technology Center Foundation (FCTH-Brazil) to determine the resulting balance of runoff/infiltration. 2- The original slope, applying thresholds from which it's possible to determine greater tendency for runoff (in percents). 3- The minimal features of relief, combining the curvature of surface in plant and profile. Those three key variables were combined in a Geographic Information System in a series of

  3. 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.

  4. DEVELOPMENT OF MORE-EFFICIENT GAS FLOODING APPLICABLE TO SHALLOW RESERVOIRS

    SciTech Connect

    William R. Rossen; Russell T. Johns; Gary A. Pope

    2003-08-21

    The objective of this research is to widen the applicability of gas flooding to shallow oil reservoirs by reducing the pressure required for miscibility using gas enrichment and increasing sweep efficiency with foam. Task 1 examines the potential for improved oil recovery with enriched gases. Subtask 1.1 examines the effect of dispersion processes on oil recovery and the extent of enrichment needed in the presence of dispersion. Subtask 1.2 develops a fast, efficient method to predict the extent of enrichment needed for crude oils at a given pressure. Task 2 develops improved foam processes to increase sweep efficiency in gas flooding. Subtask 2.1 comprises mechanistic experimental studies of foams with N2 gas. Subtask 2.2 conducts experiments with CO{sub 2} foam. Subtask 2.3 develops and applies a simulator for foam processes in field application.

  5. 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.

  6. Pore-Scale Study of Miscible Displacements in Porous Media Using Lattice Boltzmann Method

    NASA Astrophysics Data System (ADS)

    Zhang, Ting; Shi, Baochang; Huang, Changsheng; Liang, Hong

    2015-12-01

    In the past few years, the miscible displacements in porous media were usually simulated by some semiempirical models based on the volume averaging at the representative elementary volume scale. To better understand the microscopic mechanism of the viscous fingering phenomenon in porous media for miscible fluids, in this paper the miscible displacements processes in porous media are studied using the lattice Boltzmann method (LBM) at the pore scale. First, the code of LBM is tested by simulating the displacement process of two miscible fluids with the same viscosity between two parallel plates which is the well-known Taylor-Aris dispersion problem, and comparing the results with the theoretical predictions. Then, the effects of the Péclet number Pe, the viscosity ratio M and the structure of the porous media on the displacement phenomenon are investigated, and the location and velocity of the finger tip, the displacement efficiency are also studied. In this paper, the displacement efficiency is calculated by 1-m, here the quantity m is defined as m=V_M/V_T, where V_M is the volume of more viscous fluids (the displaced fluid) left behind the finger tip, V_T is the total pore volume behind the finger tip. It can be found that the "interface" of two fluids will become clearer with the increasing of the Péclet number. As Pe and M are large enough, the viscous fingering phenomenon will occur, and in the front of the finger, "mushroom-like" pattern can be observed. Besides, with the increasing of Pe or M the quantity m will be increased too, i.e., the displacement efficiency will be decreased. While Pe (or M) is greater than a certain value, the growth rate of the quantity m will slow down. The same trend was observed for the miscible displacement in capillary tubes or Hele-Shaw cells. Besides, changing the structure of the porous media makes the finger pattern different. The present simulation results provide a good understanding of the microscopic mechanism of the

  7. Prediction on miscibility of silicone and gasoline components by Monte Carlo simulation.

    PubMed

    Li, Qingyin; Liu, Dong; Song, Linhua; Wu, Pingping; Yan, Zifeng

    2014-05-01

    The miscibility behavior between silicone materials and mixed gasoline components was explored via Monte Carlo simulation. The variation of energy of mixing and Gibbs energy of mixing between silicone and gasoline components shifted with temperature was calculated. The findings indicated that the miscibility of gasoline components was exceptional in silicone 2 and the selectivity of thiophene was superior to that of other silicones, which resulted from the ester groups and methyl side chains. The density of methyl side chains in silicone 2 was significantly higher than other silicones; therefore, it could explain the lower energy of mixing and higher selectivity concerning silicone 2 and thiophene. The energy of mixing between silicone 2 and gasoline components declined with the increasing temperature (300-500 K). Nevertheless, the more increased the temperature, the more decreased the selectivity of thiophene. At 350 K, it was essential for us to research the miscibility between silicone 2 and gasoline components further. The value of Gibbs energy of mixing for silicone 2 was considerably smaller than that of the hydrocarbons at 350 K. It could be demonstrated that the miscibility between silicone 2 and thiophene was better than that of hydrocarbons. Accordingly, we should attach importance to silicone 2 in the gasoline desulfurization process.

  8. Modeling a glacial lake outburst flood process chain: the case of Lake Palcacocha and Huaraz, Peru

    NASA Astrophysics Data System (ADS)

    Somos-Valenzuela, Marcelo A.; Chisolm, Rachel E.; Rivas, Denny S.; Portocarrero, Cesar; McKinney, Daene C.

    2016-07-01

    One of the consequences of recent glacier recession in the Cordillera Blanca, Peru, is the risk of glacial lake outburst floods (GLOFs) from lakes that have formed at the base of retreating glaciers. GLOFs are often triggered by avalanches falling into glacial lakes, initiating a chain of processes that may culminate in significant inundation and destruction downstream. This paper presents simulations of all of the processes involved in a potential GLOF originating from Lake Palcacocha, the source of a previously catastrophic GLOF on 13 December 1941, killing about 1800 people in the city of Huaraz, Peru. The chain of processes simulated here includes (1) avalanches above the lake; (2) lake dynamics resulting from the avalanche impact, including wave generation, propagation, and run-up across lakes; (3) terminal moraine overtopping and dynamic moraine erosion simulations to determine the possibility of breaching; (4) flood propagation along downstream valleys; and (5) inundation of populated areas. The results of each process feed into simulations of subsequent processes in the chain, finally resulting in estimates of inundation in the city of Huaraz. The results of the inundation simulations were converted into flood intensity and preliminary hazard maps (based on an intensity-likelihood matrix) that may be useful for city planning and regulation. Three avalanche events with volumes ranging from 0.5 to 3 × 106 m3 were simulated, and two scenarios of 15 and 30 m lake lowering were simulated to assess the potential of mitigating the hazard level in Huaraz. For all three avalanche events, three-dimensional hydrodynamic models show large waves generated in the lake from the impact resulting in overtopping of the damming moraine. Despite very high discharge rates (up to 63.4 × 103 m3 s-1), the erosion from the overtopping wave did not result in failure of the damming moraine when simulated with a hydro-morphodynamic model using excessively conservative soil

  9. Modeling a Glacial Lake Outburst Flood Process Chain: The Case of Lake Palcacocha and Huaraz, Peru

    NASA Astrophysics Data System (ADS)

    Chisolm, Rachel; Somos-Valenzuela, Marcelo; Rivas Gomez, Denny; McKinney, Daene C.; Portocarrero Rodriguez, Cesar

    2016-04-01

    One of the consequences of recent glacier recession in the Cordillera Blanca, Peru, is the risk of Glacial Lake Outburst Floods (GLOFs) from lakes that have formed at the base of retreating glaciers. GLOFs are often triggered by avalanches falling into glacial lakes, initiating a chain of processes that may culminate in significant inundation and destruction downstream. This paper presents simulations of all of the processes involved in a potential GLOF originating from Lake Palcacocha, the source of a previously catastrophic GLOF on December 13, 1941, 1800 people in the city of Huaraz, Peru. The chain of processes simulated here includes: (1) avalanches above the lake; (2) lake dynamics resulting from the avalanche impact, including wave generation, propagation, and run-up across lakes; (3) terminal moraine overtopping and dynamic moraine erosion simulations to determine the possibility of breaching; (4) flood propagation along downstream valleys; and (5) inundation of populated areas. The results of each process feed into simulations of subsequent processes in the chain, finally resulting in estimates of inundation in the city of Huaraz. The results of the inundation simulations were converted into flood intensity and hazard maps (based on an intensity-likelihood matrix) that may be useful for city planning and regulation. Three avalanche events with volumes ranging from 0.5-3 x 106 m3 were simulated, and two scenarios of 15 m and 30 m lake lowering were simulated to assess the potential of mitigating the hazard level in Huaraz. For all three avalanche events, three-dimensional hydrodynamic models show large waves generated in the lake from the impact resulting in overtopping of the damming-moraine. Despite very high discharge rates (up to 63.4 x 103 m3/s), the erosion from the overtopping wave did not result in failure of the damming-moraine when simulated with a hydro-morphodynamic model using excessively conservative soil characteristics that provide very

  10. Process-Based Modeling of Floods Through Shrub Carrs of Varying Densities

    NASA Astrophysics Data System (ADS)

    Smith, J.

    2001-12-01

    Floodplain surfaces typically are protected from erosion during deep overbank flows by vegetation of varying types and densities. Drag on stems, branches, leaves, and exposed roots of the floodplain plants reduces both the near-bed flow and the fluid forces on the sediment grains. The drag on vegetation and on topographic elements of the floodplain surface can be calculated by carefully applying fundamental fluid-mechanical principals. Doing so requires identification and appropriate approximation of the reference velocity in the drag equation, and accurate estimates of the floodplain plant geometries and spacings. For shrubs, calculations indicate that skin friction on leaves is negligible compared to form drag on stems and branches, whereas, for uncut grasses, skin friction on the fronds is of primary importance. Scaling relationships are developed for each shrub species for specific applications, so that the fluid mechanically important properties can be estimated from mean stem diameters, mean stem group diameters, and mean stem group spacings. Stem group spacings and diameters can be related to shrub-canopy spacings and diameters respectively, which are determined from aerial photographs in the applications. A process-based model incorporating the necessary principles was developed and applied to a headwater tributary of East Plum Creek, Colorado. Calculations using the estimated decrease in density of the sandbar willows along this tributary accurately postdict the site of initiation of floodplain unraveling (transformation from a narrow, sinuous stream to a wide, straight one) that occurred during an extreme flood in 1965. Details of this application are presented in an accompanying poster. The model then is applied to Clark Fork of the Columbia River in the Deer Lodge Valley, Montana. This meandering fluvial system is an EPA Superfund site, because the flood-of-record in 1908 deposited several decimeters of contaminated tailings in the meander belt. The

  11. Towards a robust assessment of bridge clogging processes in flood risk management

    NASA Astrophysics Data System (ADS)

    Gschnitzer, T.; Gems, B.; Mazzorana, B.; Aufleger, M.

    2017-02-01

    River managers are aware that wood-clogging mechanisms frequently trigger damage-causing processes like structural damages at bridges, sudden channel outbursts, and occasionally, major displacements of the water course. To successfully mitigate flood risks related to the transport of large wood (LW), river managers need a guideline for an accurate and reliable risk assessment procedure and the design of river sections and bridges that are endangered of LW clogging. In recent years, comprehensive research dealing with the triggers of wood-clogging mechanisms at bridges and the corresponding impacts on flood risk was accomplished at the University of Innsbruck. A large set of laboratory experiments in a rectangular flume was conducted. In this paper we provide an overall view of these tests and present our findings. By applying a logistic regression analysis, the available knowledge on the influence of geometrical, hydraulic, and wood-related parameters on LW clogging probabilities is processed in a generalized form. Based on the experimental modeling results a practice-oriented guideline that supports the assessment of flood risk induced by LW clogging, is presented. In this context, two specific local structural protection measures at the bridge, aiming for a significant decrease of the entrapment probabilities, are illustrated: (i) a deflecting baffle installed on the upstream face of the bridge and (ii) a channel constriction leading to a change in flow state and a corresponding increase of the flow velocities and the freeboard at the bridge cross section. The presented guideline is based on a three-step approach: estimation of LW potential, entrainment, and transport; clogging scenario at the bridge; and the impact on channel and floodplain hydraulics. For a specific bridge susceptible to potential clogging caused by LW entrapment, it allows for a qualitative evaluation of potential LW entrainment in the upstream river segments, its transport toward the

  12. 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.

  13. Miscible, porous media displacements with density stratification.

    PubMed

    Riaz, Amir; Meiburg, Eckart

    2004-11-01

    High accuracy, three-dimensional numerical simulations of miscible displacements with gravity override, in both homogeneous and heterogeneous porous media, are discussed for the quarter five-spot configuration. The influence of viscous and gravitational effects on the overall displacement dynamics is described in terms of the vorticity variable. Density differences influence the flow primarily by establishing a narrow gravity layer, in which the effective Peclet number is enhanced due to the higher flow rate. Although this effect plays a dominant role in homogeneous flows, it is suppressed to some extent in heterogeneous displacements. This is a result of coupling between the viscous and permeability vorticity fields. When the viscous wavelength is much larger than the permeability wavelength, gravity override becomes more effective because coupling between the viscous and permeability vorticity fields is less pronounced. Buoyancy forces of a certain magnitude can lead to a pinch-off of the gravity layer, thereby slowing it down.

  14. Understanding processes that generate flash floods in the arid Judean Desert to the Dead Sea - a measurement network

    NASA Astrophysics Data System (ADS)

    Hennig, Hanna; Rödiger, Tino; Laronne, Jonathan B.; Geyer, Stefan; Merz, Ralf

    2016-04-01

    Flash floods in (semi-) arid regions are fascinating in their suddenness and can be harmful for humans, infrastructure, industry and tourism. Generated within minutes, an early warning system is essential. A hydrological model is required to quantify flash floods. Current models to predict flash floods are often based on simplified concepts and/or on concepts which were developed for humid regions. To more closely relate such models to local conditions, processes within catchments where flash floods occur require consideration. In this study we present a monitoring approach to decipher different flash flood generating processes in the ephemeral Wadi Arugot on the western side of the Dead Sea. To understand rainfall input a dense rain gauge network was installed. Locations of rain gauges were chosen based on land use, slope and soil cover. The spatiotemporal variation of rain intensity will also be available from radar backscatter. Level pressure sensors located at the outlet of major tributaries have been deployed to analyze in which part of the catchment water is generated. To identify the importance of soil moisture preconditions, two cosmic ray sensors have been deployed. At the outlet of the Arugot water is sampled and level is monitored. To more accurately determine water discharge, water velocity is measured using portable radar velocimetry. A first analysis of flash flood processes will be presented following the FLEX-Topo concept .(Savenije, 2010), where each landscape type is represented using an individual hydrological model according to the processes within the three hydrological response units: plateau, desert and outlet. References: Savenije, H. H. G.: HESS Opinions "Topography driven conceptual modelling (FLEX-Topo)", Hydrol. Earth Syst. Sci., 14, 2681-2692, doi:10.5194/hess-14-2681-2010, 2010.

  15. Miscible Applied Simulation Techniques for Energy Recovery

    SciTech Connect

    Zeng, Zhengwen; Chang, Shih-Hsien; Grigg, Reid B.

    2005-07-01

    During the use of MASTER at the New Mexico Petroleum Recovery Research Center (PRRC) as research division of New Mexico Institute of Mining and Technology a number of modification have been made to the original MASTER. We have worked at minimizing programming errors and incorporating a foaming option for surfactant solution (aqueous phase) injection altemating with gas (SAG) The original program checks and modifications performed at PRRC were under the direction of Dr. Shih-Hsien Chang under previous DOE contracts. The final modifications and completion of the documentation were performed by Dr. Zhengwen Zeng under DOE Contract Number DE-FG26-01BC15364. Drs. Chang and Zeng worked under Dr. Reid B. Grigg in the Gas Flooding Processes and Flow Heterogeneities Section of PRRC. This work is not intended to have any long-term support from the PRRC, but any errors should be reported to the Department of Energy for inclusion in future releases of MASTER. MASTER is an effective reservoir simulator for modeling a number of fluid flow problems and is a straight forward and economical program. We thank the Department of Energy for the original development of this program and the availability for our use.

  16. Miscible ferrofluid patterns in a radial magnetic field.

    PubMed

    Chen, Ching-Yao; Yang, Y-S; Miranda, José A

    2009-07-01

    Pattern formation in a miscible ferrofluid system is experimentally investigated. The experiment is performed by immersing a thin ferrofluid droplet in a cylindrical container, overfilling it with a nonmagnetic miscible fluid, and applying an in-plane radial magnetic field. Visually striking patterns are obtained whose morphologies change from circular at zero field to complex starburst-like structures at finite field. The evolution of miscible ferrofluid droplets of various initial diameters subjected to different magnetic-field strengths is considered. Proper rescaling of the experimental data indicates that the time evolution of the droplets' area increments obeys a universal 4/3 power-law behavior at long times.

  17. Flooded homes, broken bonds, the meaning of home, psychological processes and their impact on psychological health in a disaster.

    PubMed

    Carroll, Bob; Morbey, Hazel; Balogh, Ruth; Araoz, Gonzalo

    2009-06-01

    In 2005, Carlisle suffered severe flooding and 1600 houses were affected. A qualitative research project to study the social and health impacts was undertaken. People whose homes had been flooded and workers who had supported them were interviewed. The findings showed that there was severe disruption to people's lives and severe damage to their homes, and many suffered from psychological health issues. Phenomenological and transactional perspectives are utilised to analyse the psychological processes (identity, attachment, alienation and dialectics) underlying the meaning of home and their impact on psychological health. Proposals for policy and practice are made.

  18. Design by Nature in a Confined Flood Alleviation Scheme: Analysis of Form-Process Feedbacks and Morphological Evolution

    NASA Astrophysics Data System (ADS)

    Hetherington, D.; German, S.

    2015-12-01

    any conventional hard flood risk alleviation schemes have been detrimental to natural geomorphic processes and have damaged fluvial habitats. This is primarily due to the over-riding focus on managing flood risk by dictating channel capacity and hydraulics, which is not always conducive to the promotion of geomorphologically-healthy and diverse conditions that allow and promote natural processes. This paper explains how the principles of fluvial geomorphology had a large influence on the design, construction and post project monitoring of a flood alleviation scheme in Wales within a heavily confined river corridor that is designated as having special ecological status; without adversely impacting on flood risk. The challenge was to ensure that the physical habitat required by the important species (including Atlantic Salmon and Ranunculus) were retained and that the surrounding infrastructure and properties were not at risk of being undercut as a result of scour in the confined high energy channel. A geomorphologically-guided soft engineering approach was taken to promote local morphological diversity and flow diversity, utilising information from up and downstream natural river reaches, and general geomorphological principles. The proposed layout was modelled in 1D to understand the effects of the reprofiling on flows, allowing for a basic assessment of coarse sediment transport to be undertaken. A combination of terrestrial laser scanning and contact GPS surveys were used to monitor morphological evolution post construction, and to determine how morphological form adjusted post-construction within the confined channel. This paper will introduce the guiding principles of process restoration that influenced scheme design, and then report on the morphological evolution of the river channel that occurred as river processes produced and maintained a dynamic, diverse and healthy physical habitat. Keywords: Process Restoration; Form Process Feedbacks; Fluvial

  19. Improved Efficiency of Miscible C02 Floods and Enhanced Prospects for C02 Flooding Heterogeneous Reservoirs

    SciTech Connect

    Boyn Guo; David S. Schechter; Jyun-Syung Tsau; Reid B. Grigg; Shih-Hsien Chang

    1996-10-10

    Surfactant and foam properties have been evaluated at high pressure using the foam durability apparatus. For a number of surfactant solutions the interfacial tension with cense CO2, critical micelle concentrations, foaming ability, and foam stability were determined. Preliminary results show that these tests correlate well to predict surfactant properties and mobility in cores. Work has also restarted in the parallel-dual permeability system.

  20. Grid infrastructure for automatic processing of SAR data for flood applications

    NASA Astrophysics Data System (ADS)

    Kussul, Natalia; Skakun, Serhiy; Shelestov, Andrii

    2010-05-01

    More and more geosciences applications are being put on to the Grids. Due to the complexity of geosciences applications that is caused by complex workflow, the use of computationally intensive environmental models, the need of management and integration of heterogeneous data sets, Grid offers solutions to tackle these problems. Many geosciences applications, especially those related to the disaster management and mitigations require the geospatial services to be delivered in proper time. For example, information on flooded areas should be provided to corresponding organizations (local authorities, civil protection agencies, UN agencies etc.) no more than in 24 h to be able to effectively allocate resources required to mitigate the disaster. Therefore, providing infrastructure and services that will enable automatic generation of products based on the integration of heterogeneous data represents the tasks of great importance. In this paper we present Grid infrastructure for automatic processing of synthetic-aperture radar (SAR) satellite images to derive flood products. In particular, we use SAR data acquired by ESA's ENVSAT satellite, and neural networks to derive flood extent. The data are provided in operational mode from ESA rolling archive (within ESA Category-1 grant). We developed a portal that is based on OpenLayers frameworks and provides access point to the developed services. Through the portal the user can define geographical region and search for the required data. Upon selection of data sets a workflow is automatically generated and executed on the resources of Grid infrastructure. For workflow execution and management we use Karajan language. The workflow of SAR data processing consists of the following steps: image calibration, image orthorectification, image processing with neural networks, topographic effects removal, geocoding and transformation to lat/long projection, and visualisation. These steps are executed by different software, and can be

  1. Process, mechanism and impacts of scale formation in alkaline flooding by a variable porosity and permeability model

    NASA Astrophysics Data System (ADS)

    Zhang, Zhen; Li, Jiachun

    2016-06-01

    In spite of the role of alkali in enhancing oil recovery (EOR), the formation of precipitation during alkaline-surfactant-polymer (ASP) flooding can severely do harm to the stratum of oil reservoirs, which has been observed in situ tests of oil fields such as scale deposits found in oil stratum and at the bottom of oil wells. On the other hand, remarkable variation of stratum parameters, e.g., pore radius, porosity, and permeability due to scale formation considerably affects seepage flow and alkaline flooding process in return. The objective of this study is to firstly examine these mutual influential phenomena and corresponding mechanisms along with EOR during alkaline flooding when the effects of precipitation are no longer negligible. The chemical kinetic theory is applied for the specific fundamental reactions to describe the process of rock dissolution in silica-based reservoirs. The solubility product principle is used to analyze the mechanism of alkali scale formation in flooding. Then a 3D alkaline flooding coupling model accounting for the variation of porosity and permeability is established to quantitatively estimate the impact of alkali scales on reservoir stratum. The reliability of the present model is verified in comparison with indoor experiments and field tests of the Daqing oil field. Then, the numerical simulations on a 1/4 well group in a 5-spot pattern show that the precipitation grows with alkali concentration, temperature, and injection pressure and, thus, reduces reservoir permeability and oil recovery correspondingly. As a result, the selection of alkali with a weak base is preferable in ASP flooding by tradeoff strategy.

  2. Sedimentary processes of the Kusawa Lake torrent system, Yukon, Canada, as revealed by the September 16, 1982 flood event

    NASA Astrophysics Data System (ADS)

    Lowey, Grant W.

    2002-08-01

    The Kusawa Lake torrent system is located in the northern Canadian Cordillera of southwestern Yukon. It is Holocene in age and consists of a catchment area, gorge and alluvial fan complex. The north compartment of the catchment is a third-order basin covering an area of 13.2 km 2. It is characterized by active slumping of Quaternary glacial deposits that supply sediment for the torrent system. The gorge is approximately 800 m long and distinguished by 10 m high vertical walls cut into granitic bedrock. The fan complex is semiconical in shape and covers an area of 1.52 km 2. The active part of the fan is plano-convex in longitudinal profile, covers an area of 0.75 km 2, and is subdivided into an upper, middle and lower fan, based on the occurrence of seven sedimentary facies that were deposited by a catastrophic flood in 1982. The upper fan is characterized by boulder gravel levees and boulder gravel lobes that were deposited by debris flows. It is also characterized by sandy boulder gravel that may represent a transition from debris flow to dominantly hyperconcentrated flow processes. The middle fan is distinguished by sandy cobble gravel and sandy pebble gravel that is interbedded with horizontally laminated sand. These sediments were deposited by hyperconcentrated flows. The lower fan is characterized by horizontally bedded and laminated sand that may represent a transition from hyperconcentrated flow to sheetflood dominant processes, and by sand channels that represent rechannelized waning-flood discharge. The fan displays downfan trends in grain size (boulders to sand), slope style (plano-concave), and slope value (4-1°) typical of sheetflood-dominated fans. The initiation of sedimentation in the Kusawa Lake torrent system was due to a combination of rainfall flooding and flooding related to catastrophic slope failure in the catchment area. Slope failure leads to the formation of a landslide dam and lake, and when the dam fails, the draining lake results in a

  3. "Physically-based" numerical experiment to determine the dominant hillslope processes during floods?

    NASA Astrophysics Data System (ADS)

    Gaume, Eric; Esclaffer, Thomas; Dangla, Patrick; Payrastre, Olivier

    2016-04-01

    To study the dynamics of hillslope responses during flood event, a fully coupled "physically-based" model for the combined numerical simulation of surface runoff and underground flows has been developed. A particular attention has been given to the selection of appropriate numerical schemes for the modelling of both processes and of their coupling. Surprisingly, the most difficult question to solve, from a numerical point of view, was not related to the coupling of two processes with contrasted kinetics such as surface and underground flows, but to the high gradient infiltration fronts appearing in soils, source of numerical diffusion, instabilities and sometimes divergence. The model being elaborated, it has been successfully tested against results of high quality experiments conducted on a laboratory sandy slope in the early eighties, which is still considered as a reference hillslope experimental setting (Abdul & Guilham). The model appeared able to accurately simulate the pore pressure distributions observed in this 1.5 meter deep and wide laboratory hillslope, as well as its outflow hydrograph shapes and the measured respective contributions of direct runoff and groundwater to these outflow hydrographs. Based on this great success, the same model has been used to simulate the response of a theoretical 100-meter wide and 10% sloped hillslope, with a 2 meter deep pervious soil and impervious bedrock. Three rain events have been tested: a 100 millimeter rainfall event over 10 days, over 1 day or over one hour. The simulated responses are hydrologically not realistic and especially the fast component of the response, that is generally observed in the real-world and explains flood events, is almost absent of the simulated response. Thinking a little about the whole problem, the simulation results appears totally logical according to the proposed model. The simulated response, in fact a recession hydrograph, corresponds to a piston flow of a relatively uniformly

  4. Pre- and post-processing of hydro-meteorological ensembles for the Norwegian flood forecasting system in 145 basins.

    NASA Astrophysics Data System (ADS)

    Jahr Hegdahl, Trine; Steinsland, Ingelin; Merete Tallaksen, Lena; Engeland, Kolbjørn

    2016-04-01

    Probabilistic flood forecasting has an added value for decision making. The Norwegian flood forecasting service is based on a flood forecasting model that run for 145 basins. Covering all of Norway the basins differ in both size and hydrological regime. Currently the flood forecasting is based on deterministic meteorological forecasts, and an auto-regressive procedure is used to achieve probabilistic forecasts. An alternative approach is to use meteorological and hydrological ensemble forecasts to quantify the uncertainty in forecasted streamflow. The hydrological ensembles are based on forcing a hydrological model with meteorological ensemble forecasts of precipitation and temperature. However, the ensembles of precipitation are often biased and the spread is too small, especially for the shortest lead times, i.e. they are not calibrated. These properties will, to some extent, propagate to hydrological ensembles, that most likely will be uncalibrated as well. Pre- and post-processing methods are commonly used to obtain calibrated meteorological and hydrological ensembles respectively. Quantitative studies showing the effect of the combined processing of the meteorological (pre-processing) and the hydrological (post-processing) ensembles are however few. The aim of this study is to evaluate the influence of pre- and post-processing on the skill of streamflow predictions, and we will especially investigate if the forecasting skill depends on lead-time, basin size and hydrological regime. This aim is achieved by applying the 51 medium-range ensemble forecast of precipitation and temperature provided by the European Center of Medium-Range Weather Forecast (ECMWF). These ensembles are used as input to the operational Norwegian flood forecasting model, both raw and pre-processed. Precipitation ensembles are calibrated using a zero-adjusted gamma distribution. Temperature ensembles are calibrated using a Gaussian distribution and altitude corrected by a constant gradient

  5. Reducing uncertainty in the selection of bi-variate distributions of flood peaks and volumes using copulas and hydrological process-based model selection

    NASA Astrophysics Data System (ADS)

    Szolgay, Jan; Gaál, Ladislav; Bacigál, Tomáš; Kohnová, Silvia; Blöschl, Günter

    2016-04-01

    Bi-variate distributions of flood peaks and flood event volumes are needed for a range of practical purposes including e.g. retention basin design and identifying extent and duration of flooding in flood hazard zones. However, the selection of the types of bi-variate distributions and estimating their parameters from observed peak-volume pairs are associated with far larger uncertainties compared to uni-variate distributions, since observed flood records of required length are rarely available. This poses a serious problem to reliable flood risk estimation in bi-variate design cases. The aim of this contribution was to shed light on the possibility of reducing uncertainties in the estimation of the dependence models/parameters from a regional perspective. The peak-volume relationships were modeled in terms of copulas. Flood events were classified according to their origin. In order to reduce the uncertainty in estimating flood risk, pooling and analyzing catchments of similar behavior according to flood process types was attempted. Most of the work reported in the literature so far did not direct the multivariate analysis toward discriminating certain types of models regionally according to specific runoff generation processes. Specifically, the contribution addresses these problems: - Are the peak-volume relationships of different flood types for a given catchment similar? - Are the peak-volume dependence structures between catchments in a larger region for given flood types similar? - Are some copula types more suitable for given flood process types and does this have consequences for reliable risk estimation? The target region is located in the northern parts of Austria, and consists of 72 small and mid-sized catchments. Instead of the traditional approach that deals with annual maximum floods, the current analysis includes all independent flood events in the region. 24 872 flood events from the period 1976-2007 were identified, and classified as synoptic, flash

  6. Formation of miscible fluid microstructures by hydrodynamic focusing in plane geometries.

    PubMed

    Cubaud, Thomas; Mason, Thomas G

    2008-11-01

    We experimentally investigate the flow structures formed when two miscible fluids that have large viscosity contrasts are injected and hydrodynamically focused in plane microchannels. Parallel viscous flows composed of a central stream surrounded by symmetric sheath streams are examined as a function of the flow rates, fluid viscosities, and rates of molecular diffusion. We study miscible interfacial morphologies and show a route for manipulating viscous flow-segregation processes in plane microsystems. The diffusion layer at the boundary of an ensheathed fluid grows as function of the distance downstream and depends on the Péclet number. In particular, we observe diffusion-enhanced viscous ensheathing processes. In the presence of a constriction, we investigate the formation of a lubricated viscous thread in the converging flow and also the buckling morphologies of the thread in the diverging flow. This study, relevant to multifluid flow between a "thick" material and a "thin" solvent, demonstrates the possibility to further control steady and oscillatory miscible fluid microstructures.

  7. Deconvolving Flood Plain Dynamical Processes from Pedogenic Processes on Ancient Floodplains

    NASA Astrophysics Data System (ADS)

    Sheldon, N. D.

    2014-12-01

    Paleosols (fossil soils) preserved in ancient floodplain systems represent one of the most widely used and potentially powerful continental paleoclimatic archives. At the same time, to apply most of the quantitative paleoclimate proxies requires the deconvolution of floodplain dynamics from pedogenic processes. For example, a paleosol could be weakly developed because of low atmospheric CO2 levels, low amounts of precipitation, or because of short formation duration due to frequent channel avulsion. The interpretation of local floodplain dynamics in paleo-floodplain systems is often simplistic, assuming both straightforward uniformitarianism and also that a single vertical section represents that lateral diversity of environments, however, these assumptions have rarely, if ever, been put to the test. Herein, a variety of paleoclimatic and paleobiological proxies will be examined in well-preserved paleo-floodplain settings in Spain, Wyoming, and Montana to test those assumptions. Multi-proxy (phytolith, stable isotope) paleovegetation studies along paleo-floodplain transects in Montana (Miocene, Eocene) indicate substantial heterogeneity at the scale of tens to hundreds of meters, floodplain dynamics-driven succession, and cryptic paludal or everwet areas that are not recognizable purely on the basis of sedimentology. Similarly, rapidly aggrading floodplains in fluvial distributary systems (Spain, Miocene) or in dryland basins (Montana) often record significant mismatches between paleosol-based and paleobotanically based estimates of paleoprecipitation, likely due to variable sediment accumulation rates. Both of those sets of results indicate that single vertical sections are unlikely to represent the breadth floodplain environments and properties operating across paleo-floodplain systems. In contrast, newly described mineralogical proxies based on rock magnetics that can be used to reconstruct paleoclimatic/paleoenvironmental properties appear to be robust at the

  8. CO{sub 2} huff-n-puff process in a light oil shallow carbonate reservoir. Annual report, January 1, 1996--December 31, 1996

    SciTech Connect

    Prieditis, J.; Wehner, S.

    1998-01-01

    The application of cyclic CO{sub 2}, often referred to as the CO{sub 2} Huff-n-Puff process, may find its niche in the maturing waterfloods of the Permian Basin. Coupling the CO{sub 2} H-n-P process to miscible flooding applications could provide the needed revenue to sufficiently mitigate near-term negative cash flow concerns in the capital intensive miscible projects. Texaco Exploration & Production Inc. and the U.S. Department of Energy have teamed up in an attempt to develop the CO{sub 2} Huff-n-Puff process in the Grayburg and San Andres formations; a light oil, shallow shelf carbonate reservoir that exists throughout the Permian Basin. A significant amount of oil reserves are located in carbonate reservoirs. Specifically, the carbonates deposited in shallow shelf (SSC) environments make up the largest percentage of known reservoirs within the Permian Basin of North America. Many of these known resources have been under waterflooding operations for decades and are at risk of abandonment if crude oil recoveries cannot be economically enhanced. The selected site for this demonstration project is the Central Vacuum Unit waterflood in Lea County, New Mexico. Miscible CO{sub 2} flooding is the process of choice for enhancing recovery of light oils and already accounts for over 12% of the Permian Basin`s daily production. There are significant probable reserves associated with future miscible CO{sub 2} projects. However, many are marginally economic at current market conditions due to large up-front capital commitments for a peak response which may be several years in the future. The resulting negative cash-flow is sometimes too much for an operator to absorb. The CO{sub 2} H-n-P process is being investigated as a near-term option to mitigate the negative cash-flow situation--allowing acceleration of inventoried miscible CO{sub 2} projects when coupled together.

  9. Uphill diffusion and phase separation in partially miscible multicomponent mixtures

    NASA Astrophysics Data System (ADS)

    He, Ping; Raghavan, Ashwin; Ghoniem, Ahmed

    2015-11-01

    The partially miscible multicomponent mixtures, which are frequently encountered in green chemistry processes, often exhibit complicated behaviors, and are critical to the production rate, energy efficiency, and pollution controls. Recent studies have been mainly focused on phase behaviors. However, the coupled phase equilibrium and transport process, which may be the answer to phase separations observed in experiments, is not well researched. Here, we present a numerical and theoretical study on coupled mixing of heavy oil and supercritical water, and the results of our state-of-art modeling agree with experimental measurements. We find that due to the non-ideal diffusion driving force, (1) strong uphill diffusion of heavy oil fractions occurs, (2) a new heavy oil phase is separated starting from the plait point, and heavy fractions become highly concentrated, and (3) water diffusion initially overshoots in oil, and is expelled lately. Finally, we conclude our analysis applicable to different molecules and conditions. The authors thank Saudi Aramco for supporting this work (contract number 6600023444).

  10. Analysis of flash flood-triggering rainfall for a process-oriented hydrological model

    NASA Astrophysics Data System (ADS)

    Garambois, P. A.; Larnier, K.; Roux, H.; Labat, D.; Dartus, D.

    2014-02-01

    We propose an extended study of recent flood-triggering storms and resulting hydrological responses for catchments in the Pyrenean foothills up to the Aude region. For hydrometeorological sciences, it appears relevant to characterize flash floods and the storm that triggered them over various temporal and spatial scales. There are very few studies of extreme storm-caused floods in the literature covering the Mediterranean and highlighting, for example, the quickness and seasonality of this natural phenomenon. The present analysis is based on statistics that clarify the dependence between the spatial and temporal distributions of rainfall at catchment scale, catchment morphology and runoff response. Given the specific space and time scales of rainfall cell development, we show that the combined use of radar and a rain gauge network appears pertinent. Rainfall depth and intensity are found to be lower for catchments in the Pyrenean foothills than for the nearby Corbières or Montagne Noire regions. We highlight various hydrological behaviours and show that an increase in initial soil saturation tends to foster quicker catchment flood response times, of around 3 to 10 h. The hydrometeorological data set characterized in this paper constitutes a wealth of information to constrain a physics-based distributed model for regionalization purposes in the case of flash floods. Moreover, the use of diagnostic indices for rainfall distribution over catchment drainage networks highlights a unimodal trend in spatial temporal storm distributions for the entire flood dataset. Finally, it appears that floods in mountainous Pyrenean catchments are generally triggered by rainfall near the catchment outlet, where the topography is lower.

  11. Miscibility Study of PCBM/P3EHT Organic Photovoltaics via Small Angle Neutron Scattering

    NASA Astrophysics Data System (ADS)

    Yin, Wen; McCulloch, Bryan; Segalman, Rachel; Dadmun, Mark

    2011-03-01

    Organic photovoltaics (OPV) attracted considerable interest as lightweight, inexpensive, and easily processable replacement of inorganic photovoltaics. Current results indicate that the morphology of these photovoltaic materials is essential to their solar energy conversion efficiency but a detailed and fundamental understanding is absent. In this paper, the miscibility and structure of P3EHT/PCBM composites with varying PCBM loading level are investigated via small angle neutron scattering (SANS). With P3EHT having a melting temperature below 100°C, SANS experiments of the blends are conducted above the melting point to unequivocally determine the miscibility of PCBM and P3EHT without the added complexity of polymer crystals. Our SANS results show that blends with 20 and 50 wt% PCBM exhibit dramatically larger scattering at low-Q regime relative to 10 and 15wt% PCBM samples. This result implies that the miscibility limit of PCBM and P3EHT lies between 15:85 and 20:80. Further analysis is underway to correlate these results to OPV efficiency.

  12. Buoyant miscible displacement flows in vertical pipe

    NASA Astrophysics Data System (ADS)

    Amiri, A.; Larachi, F.; Taghavi, S. M.

    2016-10-01

    The displacement flow of two miscible Newtonian fluids is investigated experimentally in a vertical pipe of long aspect ratio (δ-1 ≈ 210). The fluids have a small density difference and they have the same viscosity. The heavy displacing fluid is initially placed above the light displaced fluid. The displacement flow is downwards. The experiments cover a wide range of the two dimensionless parameters that largely describe the flow: the modified Reynolds number (0 ≤ Ret⪅800) and the densimetric Froude number (0 ≤ Fr ≤ 24). We report on the stabilizing effect of the imposed flow and uncover the existence of two main flow regimes at long times: a stable displacement flow and an unstable displacement flow. The transition between the two regimes occurs at a critical modified Reynolds number " separators=" R et | Critical , as a function of Fr. We study in depth the stable flow regime: First, a lubrication model combined with a simple initial acceleration formulation delivers a reasonable prediction to the time-dependent penetrating displacing front velocity. Second, we find two sub-regimes for stable displacements, namely, sustained-back-flows and no-sustained-back-flows. The transition between the two sub-regimes is a marginal stationary interface flow state, which is also well predicted by the lubrication model. The unstable regime is associated to instabilities and diffusive features of the flow. In addition, particular patterns such as front detachment phenomenon appear in the unstable flow regime, for which we quantify the regions of existence versus the dimensionless groups.

  13. Assessment Approach for Identifying Compatibility of Restoration Projects with Geomorphic and Flooding Processes in Gravel Bed Rivers.

    PubMed

    DeVries, Paul; Aldrich, Robert

    2015-08-01

    A critical requirement for a successful river restoration project in a dynamic gravel bed river is that it be compatible with natural hydraulic and sediment transport processes operating at the reach scale. The potential for failure is greater at locations where the influence of natural processes is inconsistent with intended project function and performance. We present an approach using practical GIS, hydrologic, hydraulic, and sediment transport analyses to identify locations where specific restoration project types have the greatest likelihood of working as intended because their function and design are matched with flooding and morphologic processes. The key premise is to identify whether a specific river analysis segment (length ~1-10 bankfull widths) within a longer reach is geomorphically active or inactive in the context of vertical and lateral stabilities, and hydrologically active for floodplain connectivity. Analyses involve empirical channel geometry relations, aerial photographic time series, LiDAR data, HEC-RAS hydraulic modeling, and a time-integrated sediment transport budget to evaluate trapping efficiency within each segment. The analysis segments are defined by HEC-RAS model cross sections. The results have been used effectively to identify feasible projects in a variety of alluvial gravel bed river reaches with lengths between 11 and 80 km and 2-year flood magnitudes between ~350 and 1330 m(3)/s. Projects constructed based on the results have all performed as planned. In addition, the results provide key criteria for formulating erosion and flood management plans.

  14. Miscible Quarter Five-Spot Flows in Porous Media

    NASA Astrophysics Data System (ADS)

    Chen, Ching-Yao; Meiburg, Eckart

    1997-11-01

    Miscible quarter five-spot flows in both homogeneous and heterogeneous porous media were investigated by means of direct numerical simulations based on compact finite differences. Comparisons of the algebraic growth rate and the preferred wave number of the viscous fingering instability with analytical linear stability results demonstrate excellent accuracy. A series of simulations illustrate the effects of the mobility ratio R, the dimensionless flow rate Pe, and the heterogeneity on the displacement process. For sufficiently large R and Pe, the homogeneous flow gives rise to a vigorous fingering instability, along with strong nonlinear interactions among the fingers. The spatial nonuniformity of the potential base flow leads to a clear separation in space and time of the large and small scales in the flow field. Small scales occur predominantly during the early stages near the injection well, and at late times near the production well. The central domain is dominated by larger scales. Both local and integral flow features are quantified by means of concentration, vorticity, stream function, and sweep efficiency data. For heterogeneous porous media, the influence of the parameters characterizing the permeability variation was investigated. Typically, the minimal sweep efficiency was observed at intermediate values of the correlation length. Partially supported by Chevron Petroleum Technology Co.

  15. Optical Studies of model binary miscibility gap system

    NASA Technical Reports Server (NTRS)

    Lacy, L. L.; Witherow, W. K.; Facemire, B. R.; Nishioka, G. M.

    1982-01-01

    In order to develop a better understanding of separation processes in binary miscibility gap metal alloys, model transparent fluid systems were studied. The system selected was diethylene glycol-ethyl salicylate which has convenient working temperatures (288 to 350 K), low toxicity, and is relatively easy to purify. The system is well characterized with respect to its phase diagram, density, surface and interfacial tensions, viscosity and other pertinent physical properties. Studies of migration of the dispersed phase in a thermal gradient were performed using conventional photomicroscopy. Velocities of the droplets of the dispersed phase were measured and compared to calculated rates which included both Stokes and thermal components. A holographic microscopy system was used to study growth, coalescence, and particle motions. Sequential holograms allowed determination of particle size distribution changes with respect to time and temperature. Holographic microscopy is capable of recording particle densities up to 10 to the 7th power particles/cu cm and is able to resolve particles of the order of 2 to 3 microns in diameter throughout the entire volume of the test cell. The reconstructed hologram produces a wavefront that is identical to the original wavefront as it existed when the hologram was made. The reconstructed wavefront is analyzed using a variety of conventional optical methods.

  16. CO2 Huff-n-Puff Process in a Light Oil Shallow Shelf Carbonate Reservoir

    SciTech Connect

    Boomer, R.J.; Cole, R.; Kovar, M.; Prieditis, J.; Vogt, J.; Wehner, S.

    1999-02-24

    The application cyclic CO2, often referred to as the CO2 Huff-n-Puff process, may find its niche in the maturing waterfloods of the Permian Basin. Coupling the CO2 Huff-n-Puff process to miscible flooding applications could provide the needed revenue to sufficiently mitigate near-term negative cash flow concerns in capital-intensive miscible projects. Texaco Exploration and Production Inc. and the US Department of Energy have teamed up in a attempt to develop the CO2 Huff-n-Puff process in the Grayburg and San Andres formations which are light oil, shallow shelf carbonate reservoirs that exist throughout the Permian Basin. This cost-shared effort is intended to demonstrate the viability of this underutilized technology in a specific class of domestic reservoir.

  17. Mapping hazards from glacier lake outburst floods based on modelling of process cascades at Lake 513, Carhuaz, Peru

    NASA Astrophysics Data System (ADS)

    Schneider, D.; Huggel, C.; Cochachin, A.; Guillén, S.; García, J.

    2014-01-01

    Recent warming has had enormous impacts on glaciers and high-mountain environments. Hazards have changed or new ones have emerged, including those from glacier lakes that form as glaciers retreat. The Andes of Peru have repeatedly been severely impacted by glacier lake outburst floods in the past. An important recent event occurred in the Cordillera Blanca in 2010 when an ice avalanche impacted a glacier lake and triggered an outburst flood that affected the downstream communities and city of Carhuaz. In this study we evaluate how such complex cascades of mass movement processes can be simulated coupling different physically-based numerical models. We furthermore develop an approach that allows us to elaborate corresponding hazard maps according to existing guidelines for debris flows and based on modelling results and field work.

  18. Model parameters conditioning on regional hydrologic signatures for process-based design flood estimation in ungauged basins.

    NASA Astrophysics Data System (ADS)

    Biondi, Daniela; De Luca, Davide Luciano

    2015-04-01

    The use of rainfall-runoff models represents an alternative to statistical approaches (such as at-site or regional flood frequency analysis) for design flood estimation, and constitutes an answer to the increasing need for synthetic design hydrographs (SDHs) associated to a specific return period. However, the lack of streamflow observations and the consequent high uncertainty associated with parameter estimation, usually pose serious limitations to the use of process-based approaches in ungauged catchments, which in contrast represent the majority in practical applications. This work presents the application of a Bayesian procedure that, for a predefined rainfall-runoff model, allows for the assessment of posterior parameters distribution, using the limited and uncertain information available for the response of an ungauged catchment (Bulygina et al. 2009; 2011). The use of regional estimates of river flow statistics, interpreted as hydrological signatures that measure theoretically relevant system process behaviours (Gupta et al. 2008), within this framework represents a valuable option and has shown significant developments in recent literature to constrain the plausible model response and to reduce the uncertainty in ungauged basins. In this study we rely on the first three L-moments of annual streamflow maxima, for which regressions are available from previous studies (Biondi et al. 2012; Laio et al. 2011). The methodology was carried out for a catchment located in southern Italy, and used within a Monte Carlo scheme (MCs) considering both event-based and continuous simulation approaches for design flood estimation. The applied procedure offers promising perspectives to perform model calibration and uncertainty analysis in ungauged basins; moreover, in the context of design flood estimation, process-based methods coupled with MCs approach have the advantage of providing simulated floods uncertainty analysis that represents an asset in risk-based decision

  19. COSOLVENCY OF PARTIALLY MISCIBLE ORGANIC SOLVENTS ON THE SOLUBILITY OF HYDROPHOBIC ORGANIC CHEMICALS

    EPA Science Inventory

    The cosolvency of completely miscible organic solvents (CMOSs) and partially miscible organic solvents (PMOSs) on the solubility of hydrophobic organic chemicals (HOCs) was examined, with an emphasis on PMOSs. Measured solubilities were compared with predictions from the log- lin...

  20. D/H on Mars: Effects of floods, volcanism, impacts, and polar processes

    USGS Publications Warehouse

    Carr, M.H.

    1990-01-01

    Water in the Martian atmosphere is 5.1 times more enriched in deuterium than terrestial water. The enrichment has been previously attributed to either a massive loss of water early in the planet's history or the presence of only a very small reservoir of water that has exchanged with the atmosphere over geologic time. Both these interpretations appear inconsistent with geologic evidence of large floods and sustained volcanism. Large floods are believed to have episodically introduced large amounts of water onto the surface. During a large flood roughly 1017 g of water would almost immediately sublime into the atmospher and be frozen out on polar terrain, to form a new layer several centimeters thick. The long-term effect of a flood would depend on where the water pooled after the flood. If the water pooled at low latitudes, all the water would slowly sublime into the atmosphers and ultimately be frozen out at the poles, thereby adding several meters to the polar deposits for each flood. If the water pooled at high latitude, it would form a permanent ice deposit, largely isolated from further interchange with the atmosphere. Volcanism has also episodically introduced water into the atmosphere. Most of this water has become incorporated into the polar deposits. That released over the last 3.5 Ga could have added a few kilometers to the polar deposits, depending on the amount of dust incorporated along with the ice. Large cometary impacts would have introduced additional large amounts of water into the atmosphere. The long-term evolution of D/H in the atmosphere depends on the rate of exchange of water between the atmosphere and the polar deposits. If exchange is active, then loss rates of hydrogen from the upper atmosphere are substantially higher than those estimated by Y. L. Yung, J. Wen, J. P. Pinto, M. Allen, K. K. Pierce, and S. Paulsen [Icarus 76, 146-159 (1988)]. More plausibly, exchange of water between the atmosphere and the polar deposits is limited, so

  1. Miscibility and structure-property relationships in some novel polyolefins

    NASA Astrophysics Data System (ADS)

    Kamdar, Akshay Rajprakash

    In the first chapter, miscibility of homogeneous propylene/ethylene (P/E) copolymers of relatively narrow molecular weight distribution was studied as a function of constituent comonomer content. Polymers with up to 31 mol% ethylene were blended in pairs in order to vary the comonomer content difference. Copolymers of molecular weight about 200 kg mol-1 were miscible if the difference in ethylene content was less than about 18 mol%, and immiscible if the ethylene content difference was greater than about 20 mol%. Blends with constituent composition difference in the range of 18-20 mol% exhibited partial miscibility in the melt. In the second chapter, the effect of chain microstructure on the miscibility and phase behavior of ethylene-octene (EO) copolymer blends was studied. Binary blends of two statistical copolymers (EO/EO blends) that differed in comonomer content were compared with blends of an EO with an olefinic blocky ethylene-octene copolymer, OBC (EO/OBC blends). Two EOs of molecular weight about 100 kg/mol were miscible if the difference in octene content was less than about 10 mol% and immiscible if the octene content difference was greater than about 13 mol%. The blocky nature of the OBCs reduced the miscibility and broadened the partial miscibility window of EO/OBC blends compared to EO/EO blends. The EO/OBC blends were miscible if the octene content difference was less than 7 mol% and immiscible above 13 mol% octene content difference. In the third chapter, the adhesion of some ethylene-octene copolymers to polypropylene (PP) and high density polyethylene (HDPE) was studied in order to evaluate their suitability as compatibilizers for PP/HDPE blends. A one-dimensional model of the compatibilized blend was fabricated by layer-multiplying coextrusion. The microlayered tapes consisted of many alternating layers of PP and HDPE with a thin tie-layer inserted at each interface. The thickness of the tie-layer varied from 0.1 to 14 mum, which included

  2. Application of miscible displacement for Field MTX low permeability formations

    NASA Astrophysics Data System (ADS)

    Kuntsevich, V.; Slivkin, S.; Belozerov, V.

    2015-02-01

    Miscible displacement is a very effective method of recovery efficiency improvement. It is widely used in the world, but this technology is not widely used in Russia. For this reason, it is necessary to study global experience and physical aspects of this EOR method. The most important factors and limitations of miscible displacement application from the geological point of view (heterogeneity) and from the physical point of view (properties of injected fluids and reservoir fluids) should be determined. The results of this analysis should be tested on the low permeability reservoir of field MTX with analytical, proxy calculation and simulation methods.

  3. Multiple flow processes accompanying a dam-break flood in a small upland watershed, Centralia, Washington

    USGS Publications Warehouse

    Costa, John E.

    1994-01-01

    On October 5, 1991, following 35 consecutive days of dry weather, a 105-meter long, 37-meter wide, 5.2-meter deep concrete-lined watersupply reservoir on a hillside in the eastern edge of Centralia, Washington, suddenly failed, sending 13,250 cubic meters of water rushing down a small, steep tributary channel into the city. Two houses were destroyed, several others damaged, mud and debris were deposited in streets, on lawns, and in basements over four city blocks, and 400 people were evacuated. The cause of failure is believed to have been a sliding failure along a weak seam or joint in the siltstone bedrock beneath the reservoir, possibly triggered by increased seepage into the rock foundation through continued deterioration of concrete panel seams, and a slight rise (0.6 meters) in the pool elevation. A second adjacent reservoir containing 18,900 cubic meters of water also drained, but far more slowly, when a 41-cm diameter connecting pipe was broken by the landslide. The maximum discharge resulting from the dam-failure was about 71 cubic meters per second. A reconstructed hydrograph based on the known reservoir volume and calculated peak discharge indicates the flood duration was about 6.2 minutes. Sedimentologic evidence, high-water mark distribution, and landforms preserved in the valley floor indicate that the dam failure flood consisted of two flow phases: an initial debris flow that deposited coarse bouldery sediment along the slope-area reach as it lost volume, followed soon after by a water-flood that achieved a stage about one-half meter higher than the debris flow. The Centralia dam failure is one of three constructed dams destroyed by rapid foundation failure that defines the upper limits of an envelope curve of peak flood discharge as a function of potential energy for failed constructed dams worldwide.

  4. Perceptions of the Decision Process though Drought and Flood in the Murray-Darling Basin, Australia

    NASA Astrophysics Data System (ADS)

    Lynch, A. H.; Adler, C.; Howard, N.

    2012-12-01

    The Murray-Darling Basin incorporates Australia's three longest rivers and spans four States and one Territory. It is important for an agricultural industry worth more than AUS$9 billion per year, but is also the life source and spirit of the Indigenous Yorta Yorta people. Persistent severe drought and extreme flooding episodes have presented new challenges in the region. The exceptionally wet conditions experienced since the break of the "Millenium Drought" beg the question as to whether key drought and flood characteristics are changing due to anthropogenic climate change. Many alternative goals for the management of the Basin answer to the requirement for an evidentiary basis. A choice cannot be made on this basis alone - interests are implicated in any alternative. Here we use Q methodology, an approach that elucidates patterns of subjectivity, to explore the perspectives of Indigenous and non-Indigenous residents, workers and decision-makers in the region. We address the inherent diversity of viewpoints on the risks from and responses to flood and drought, and identify the potential for common ground.

  5. Assessment of flood hazard areas at a regional scale using an index-based approach and Analytical Hierarchy Process: Application in Rhodope-Evros region, Greece.

    PubMed

    Kazakis, Nerantzis; Kougias, Ioannis; Patsialis, Thomas

    2015-12-15

    The present study introduces a multi-criteria index to assess flood hazard areas in a regional scale. Accordingly, a Flood Hazard Index (FHI) has been defined and a spatial analysis in a GIS environment has been applied for the estimation of its value. The developed methodology processes information of seven parameters namely flow accumulation, distance from the drainage network, elevation, land use, rainfall intensity and geology. The initials of these criteria gave the name to the developed method: "FIGUSED". The relative importance of each parameter for the occurrence and severity of flood has been connected to weight values. These values are calculated following an "Analytical Hierarchy Process", a method originally developed for the solution of Operational Research problems. According to their weight values, information of the different parameters is superimposed, resulting to flood hazard mapping. The accuracy of the method has been supported by a sensitivity analysis that examines a range for the weights' values and corresponding to alternative scenarios. The presented methodology has been applied to an area in north-eastern Greece, where recurring flood events have appeared. Initially FIGUSED method resulted to a Flood Hazard Index (FHI) and a corresponding flood map. A sensitivity analysis on the parameters' values revealed some interesting information on the relative importance of each criterion, presented and commented in the Discussion section. Moreover, the sensitivity analysis concluded to a revised index FHIS (methodology named FIGUSED-S) and flood mapping, supporting the robustness of FIGUSED methodology. A comparison of the outcome with records of historical flood events confirmed that the proposed methodology provides valid results.

  6. Flow prediction using stochastic emulators of flood wave propagation process: middle Vistula case study

    NASA Astrophysics Data System (ADS)

    Romanowicz, Renata; Karamuz, Emilia; Kochanek, Krzysztof

    2014-05-01

    Flow predictions along the river reach are required for flood protection, flood risk assessment and also for the planning of water infrastructures and water management. Due to uncertainties involved in hydro-meteorological observations and mathematical modelling, the predictions are always uncertain. Their uncertainty increases with an increase of the time horizon of the prediction - e.g. when forecasts of flow are required many days ahead. Apart from the uncertainty, also the speed of forecast acquisition might also be of concern, in particular when fast preventive actions should be taken to issue flood warning to the public, or some water management actions should be performed. In these cases, the stochastic emulators of flood wave propagation might be very useful. The emulators can be based on available data but also be built using the modelled flows along the river in the absence of the required observations. The middle River Vistula reach stretches between Zawichost and Warsaw and is 100 km long. Two distributed flow routing models were built for the reach based on the detailed river channel and floodplain geometry data. These models are used for the temporal and spatial interpolation of the water level observations available at only 5 cross-sections and in the form of daily averages of water levels. The observations span over 50 years, but they are irregular, with long periods missing either flow or level data. The observed and modelled water level data were used to build stochastic emulators in the form of a nonlinear transformation of water levels at cross-sections along the river reach. The validation of the emulators and the comparison of their performance are done using the available observations of water levels at those cross-sections. A discussion is given on the uncertainty of predictions and the application of emulators to on-line forecasting. This work was partly supported by the project "Stochastic flood forecasting system (The River Vistula reach

  7. Molecular dynamics of binary and ternary nanodroplets with a miscibility gap

    NASA Astrophysics Data System (ADS)

    Wilemski, Gerald; Hrahsheh, Fawaz

    2012-02-01

    The structure of nanodroplets plays an important role in many natural processes including particle nucleation and aerosol formation in the atmosphere. Among other factors, chemical miscibility and surface tension strongly affect the structure of multicomponent nanodroplets at low temperature. Here, we investigate the structure of water/nonane and water/butanol/nonane nanodroplets using molecular dynamics (MD). Our MD results confirm our theoretical predictions of nonspherical nanodroplet (Russian-Doll) structures at low temperatures using density functional and lattice Monte Carlo techniques. We systematically study the variation of the droplet structure with temperature and with butanol concentration.

  8. A Methodology For Flood Vulnerability Analysis In Complex Flood Scenarios

    NASA Astrophysics Data System (ADS)

    Figueiredo, R.; Martina, M. L. V.; Dottori, F.

    2015-12-01

    Nowadays, flood risk management is gaining importance in order to mitigate and prevent flood disasters, and consequently the analysis of flood vulnerability is becoming a key research topic. In this paper, we propose a methodology for large-scale analysis of flood vulnerability. The methodology is based on a GIS-based index, which considers local topography, terrain roughness and basic information about the flood scenario to reproduce the diffusive behaviour of floodplain flow. The methodology synthetizes the spatial distribution of index values into maps and curves, used to represent the vulnerability in the area of interest. Its application allows for considering different levels of complexity of flood scenarios, from localized flood defence failures to complex hazard scenarios involving river reaches. The components of the methodology are applied and tested in two floodplain areas in Northern Italy recently affected by floods. The results show that the methodology can provide an original and valuable insight of flood vulnerability variables and processes.

  9. Improvement in oil recovery using cosolvents with CO sub 2 gas floods

    SciTech Connect

    Raible, C.

    1992-01-01

    This report presents the results of investigations to improve oil recovery using cosolvents in CO{sub 2} gas floods. Laboratory experiments were conducted to evaluate the application and selection of cosolvents as additives to gas displacement processes. A cosolvent used as a miscible additive changed the properties of the supercritical gas phase. Addition of a cosolvent resulted in increased viscosity and density of the gas mixture, and enhanced extraction of oil compounds into the CO{sub 2} rich phase. Gas phase properties were measured in an equilibrium cell with a capillary viscometer and a high pressure densitometer. A number of requirements must be considered in the application of a cosolvent. Cosolvent miscibility with CO{sub 2}, brine solubility, cosolvent volatility and relative quantity of the cosolvent partitioning into the oil phase were factors that must be considered for the successful application of cosolvents. Coreflood experiments were conducted with selected cosolvents to measure oil recovery efficiency. The results indicate lower molecular weight additives, such as propane, are the most effective cosolvents to increase oil recovery.

  10. Improvement in oil recovery using cosolvents with CO{sub 2} gas floods

    SciTech Connect

    Raible, C.

    1992-01-01

    This report presents the results of investigations to improve oil recovery using cosolvents in CO{sub 2} gas floods. Laboratory experiments were conducted to evaluate the application and selection of cosolvents as additives to gas displacement processes. A cosolvent used as a miscible additive changed the properties of the supercritical gas phase. Addition of a cosolvent resulted in increased viscosity and density of the gas mixture, and enhanced extraction of oil compounds into the CO{sub 2} rich phase. Gas phase properties were measured in an equilibrium cell with a capillary viscometer and a high pressure densitometer. A number of requirements must be considered in the application of a cosolvent. Cosolvent miscibility with CO{sub 2}, brine solubility, cosolvent volatility and relative quantity of the cosolvent partitioning into the oil phase were factors that must be considered for the successful application of cosolvents. Coreflood experiments were conducted with selected cosolvents to measure oil recovery efficiency. The results indicate lower molecular weight additives, such as propane, are the most effective cosolvents to increase oil recovery.

  11. Modelling cascading and erosional processes for glacial lake outburst floods in the Quillcay catchment, Huaraz, Cordillera Blanca, Peru

    NASA Astrophysics Data System (ADS)

    Baer, Patrick; Huggel, Christian; Frey, Holger; Chisolm, Rachel; McKinney, Daene; McArdell, Brian; Portocarrero, Cesar; Cochachin, Alejo

    2016-04-01

    Huaraz as the largest city in Cordillera Blanca has faced a major disaster in 1941, when an outburst flood from Lake Palcacocha killed several thousand people and caused widespread destruction. Recent studies on glacial lake outburst flood (GLOF) modelling and early warning systems focussed on Lake Palcacocha which has regrown after the 1941 event, from a volume of half a million m3 in 1974 to a total volume of more than 17 million m3 today. However, little research has been conducted so far concerning the situation of other lakes in the Quillcay catchment, namely Lake Tullparaju (12 mill. m3) and Cuchillacocha (2.5 mill. m3), which both also pose a threat to the city of Huaraz. In this study, we modelled the cascading processes at Lake Tullparaju and Lake Cuchillacocha including rock/ice avalanches, flood wave propagation in the lake and the resulting outburst flood and debris flows. We used the 2D model RAMMS to simulate ice avalanches. Model output was used as input for analytical 2D and 3D calculations of impact waves in the lakes that allowed us to estimate dam overtopping wave height. Since the dimension of the hanging glaciers above all three lakes is comparable, the scenarios in this study have been defined similar to the previous study at Lake Palcacocha. The flow propagation model included sediment entrainment in the steeper parts of the catchment, adding up to 50% to the initial flow volume. The results for total travel time as well as for inundated areas and flow depth and velocity in the city of Huaraz are comparable to the previous studies at Lake Palcacocha. This underlines the importance of considering also these lakes within an integral hazard analysis for the city of Huaraz. A main challenge for modelling GLOFs in the Quillcay catchment using RAMMS is the long runout distance of over 22 km combined with the very low slope gradient of the river. Further studies could improve the process understanding and could focus on more detailed investigations

  12. Calcium Carbonate Crystal Growth in Porous Media, in the presence of Water Miscible and Non-Miscible Organic Fluids

    NASA Astrophysics Data System (ADS)

    Jaho, Sofia; Sygouni, Varvara; Paraskeva, Christakis A.

    2015-04-01

    The deposition of sparingly soluble salts (scaling) within porous media is a major problem encountered in many industrial and environmental applications. In the oil industry scaling causes severe operational malfunctions and, therefore, increasing the total operating and maintenance cost [1]. The most common types of sparingly soluble salts located in oil fields include carbonate and sulfate salts of calcium, strondium and barium[1,2]. Multiple phase flow and tubing surface properties are some of the factors affecting scale formation [3]. The main purpose of the present work was the investigation of the precipitation mechanisms of calcium carbonate (CaCO3) through in situ mixing of two soluble salt solutions in a flow granular medium, in the presence of water miscible organic fluid (ethylene glycol) or non-miscible organic fluid (n-dodecane). All series of experiments were carried out in a two dimensional porous medium made of Plexiglas. For all solutions used in the experiments, the contact angles with the surface of the porous medium and the interfacial tensions were measured. During the experiments, the calcium carbonate crystal growth was continuously monitored and recorded through an optical microscope equipped with a digital programmed video camera. The snap-shots were taken within specific time intervals and their detailed procession gave information concerning the crystal growth rate and kinetics. The pH of the effluent was measured and fluids samples were collected for calcium analysis using Atomic Absorption Spectroscopy (AAS). In all experiments effluent calcium concentration decreased as a function of time, suggesting that CaCO3 precipitation took place inside the porous medium. Crystals of the precipitated salt were identified using Infrared Spectroscopy (IR) and the morphology of the crystals was examined using Scanning Electron Microscopy (SEM). The induction time for precipitation of CaCO3 crystals in the presence of n-dodecane was significantly

  13. Large wood recruitment processes and transported volumes in Swiss mountain streams during the extreme flood of August 2005

    NASA Astrophysics Data System (ADS)

    Steeb, Nicolas; Rickenmann, Dieter; Badoux, Alexandre; Rickli, Christian; Waldner, Peter

    2017-02-01

    The extreme flood event that occurred in August 2005 was the most costly (documented) natural hazard event in the history of Switzerland. The flood was accompanied by the mobilization of > 69,000 m3 of large wood (LW) throughout the affected area. As recognized afterward, wood played an important role in exacerbating the damages, mainly because of log jams at bridges and weirs. The present study aimed at assessing the risk posed by wood in various catchments by investigating the amount and spatial variability of recruited and transported LW. Data regarding LW quantities were obtained by field surveys, remote sensing techniques (LiDAR), and GIS analysis and was subsequently translated into a conceptual model of wood transport mass balance. Detailed wood budgets and transport diagrams were established for four study catchments of Swiss mountain streams, showing the spatial variability of LW recruitment and deposition. Despite some uncertainties with regard to parameter assumptions, the sum of reconstructed wood input and observed deposition volumes agree reasonably well. Mass wasting such as landslides and debris flows were the dominant recruitment processes in headwater streams. In contrast, LW recruitment from lateral bank erosion became significant in the lower part of mountain streams where the catchment reached a size of about 100 km2. According to our analysis, 88% of the reconstructed total wood input was fresh, i.e., coming from living trees that were recruited from adjacent areas during the event. This implies an average deadwood contribution of 12%, most of which was estimated to have been in-channel deadwood entrained during the flood event.

  14. Stabilization of miscible viscous fingering by chemical reaction decreasing viscosity

    NASA Astrophysics Data System (ADS)

    Arai, Shuntaro; Nagatsu, Yuichiro; Shukla, Priyanka; de Wit, Anne

    2016-11-01

    Viscous fingering (VF) occurs when a more viscous fluid is displaced by a less viscous one in porous media or Hele-Shaw cells. In this study, experiment on miscible VF with chemical reaction is conducted by using a Hele-Shaw cell. Here, the chemical reaction takes place between a polymer dissolved in the more viscous solution and hydrochloric acid (HCl) dissolved in the less viscous one in the miscible interface region. The reaction decreases the viscosity of the polymer solution. The experiment shows that the reaction stabilizes VF when the flow rate is small. In the present study, the corresponding numerical simulation is also conducted. The simulation is able to reproduce the experimental results mentioned above when different diffusion coefficients are considered meaning that HCl diffuses faster than the polymer. However, the stabilization cannot be found under conditions of the same diffusivity of the reactants. These numerical results show that the different diffusivity is responsible for the stabilization of miscible VF by the chemical reaction decreasing viscosity.

  15. Development of Concentration-Dependent Diffusion Instability in Reactive Miscible Fluids Under Influence of Constant or Variable Inertia

    NASA Astrophysics Data System (ADS)

    Bratsun, Dmitry A.; Stepkina, Olga S.; Kostarev, Konstantin G.; Mizev, Alexey I.; Mosheva, Elena A.

    2016-12-01

    In this work, we focus on the processes which accompany a frontal neutralization reaction occurring between two miscible fluids filling a vertical Hele-Shaw cell. We have found that chemically-induced changes of reagent concentrations coupled with concentration- dependent diffusion (CDD) can produce spatially localized low density areas which are sensitive to the external inertial field. In the case of static gravity we have demonstrated both experimentally and theoretically that it can give rise to the development of perfectly periodic convective structure. This scenario is strikingly different from the irregular density fingering, which is typically observed in the miscible systems. When the system is under the influence of the periodic low-frequency vibrations perpendicular to the reaction front, we found numerically the excitation of a mixed-mode instability combining the double-diffusion instabilities and the Rayleigh-Taylor mechanism of the convection within the low density areas.

  16. Determining CO2 storage potential during miscible CO2 enhanced oil recovery: Noble gas and stable isotope tracers

    USGS Publications Warehouse

    Shelton, Jenna L.; McIntosh, Jennifer C.; Hunt, Andrew; Beebe, Thomas L; Parker, Andrew D; Warwick, Peter; Drake, Ronald; McCray, John E.

    2016-01-01

    Rising atmospheric carbon dioxide (CO2) concentrations are fueling anthropogenic climate change. Geologic sequestration of anthropogenic CO2 in depleted oil reservoirs is one option for reducing CO2 emissions to the atmosphere while enhancing oil recovery. In order to evaluate the feasibility of using enhanced oil recovery (EOR) sites in the United States for permanent CO2 storage, an active multi-stage miscible CO2flooding project in the Permian Basin (North Ward Estes Field, near Wickett, Texas) was investigated. In addition, two major natural CO2 reservoirs in the southeastern Paradox Basin (McElmo Dome and Doe Canyon) were also investigated as they provide CO2 for EOR operations in the Permian Basin. Produced gas and water were collected from three different CO2 flooding phases (with different start dates) within the North Ward Estes Field to evaluate possible CO2 storage mechanisms and amounts of total CO2retention. McElmo Dome and Doe Canyon were sampled for produced gas to determine the noble gas and stable isotope signature of the original injected EOR gas and to confirm the source of this naturally-occurring CO2. As expected, the natural CO2produced from McElmo Dome and Doe Canyon is a mix of mantle and crustal sources. When comparing CO2 injection and production rates for the CO2 floods in the North Ward Estes Field, it appears that CO2 retention in the reservoir decreased over the course of the three injections, retaining 39%, 49% and 61% of the injected CO2 for the 2008, 2010, and 2013 projects, respectively, characteristic of maturing CO2 miscible flood projects. Noble gas isotopic composition of the injected and produced gas for the flood projects suggest no active fractionation, while δ13CCO2 values suggest no active CO2dissolution into formation water, or mineralization. CO2 volumes capable of dissolving in residual formation fluids were also estimated along with the potential to store pure-phase supercritical CO2. Using a combination

  17. 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.

  18. Controlling Miscibility in Polyethylene-Polynorbornene Block Copolymers via Side-Group Chemistry

    NASA Astrophysics Data System (ADS)

    Mulhearn, William; Register, Richard

    Block copolymers containing a crystallizable block, such as polyethylene (PE), and an amorphous block with high glass transition temperature (Tg) are an interesting class of materials since the rigid glassy block can improve the mechanical response of the article under strain by reinforcing the crystal fold surface. However, to prepare an easily processable PE-containing block copolymer it is necessary to avoid microphase separation in the melt by selection of amorphous blocks with weak repulsive interactions against PE (low Flory interaction parameter χ or interaction energy density X) . Most such low- χ polymers are chemically similar to PE, such as copolymers of ethylene and a small amount of an α-olefin, and therefore exhibit similarly low glass transition temperatures. This work investigates a series of low- and high-Tg polymers based on substituted norbornene monomers, polymerized via ring-opening metathesis polymerization (ROMP). Hydrogenated polynorbornene derivatives possess a wide range of glass transition temperatures, and miscibility with PE can be readily tuned by the choice of substituents on the monomers (e.g. aromatic vs. aliphatic groups). Two species investigated, hydrogenated poly(cyclohexyl norbornene) and hydrogenated poly(norbornyl norbornene), have high Tg and also remain miscible with polyethylene to high molecular weight. Furthermore, we develop a set of mixing rules to qualitatively predict the solubility behavior of substituted ROMP polynorbornenes as a function of their side-groups.

  19. Serpentine diffusion trajectories and the Ouzo effect in partially miscible ternary liquid mixtures.

    PubMed

    Krishna, Rajamani

    2015-11-07

    This work investigates the transient equilibration process when partially miscible ternary liquid mixtures of two different compositions are brought into contact with each other. Diffusional coupling effects are shown to become increasingly significant as the mixture compositions approach the meta-stable regions of the phase equilibrium diagrams. The proper modelling of coupled diffusion phenomena requires the use of a Fick diffusivity matrix [D], with inclusion of non-zero off-diagonal elements. The primary objective of this article is to develop a simple, robust, procedure for the estimation of the matrix [D], using the Maxwell-Stefan (M-S) formulation as a convenient starting point. In the developed simplified approach, the Fick diffusivity matrix [D] is expressed as the product of a scalar diffusivity and the matrix of thermodynamic correction factors [Γ]. By detailed examination of experimental data for the matrix [D] in a wide variety of ternary mixtures, it is deduced that the major contribution of diffusional coupling arises from the contributions of non-ideal solution thermodynamics, quantified by the matrix of thermodynamic correction factors [Γ]. An important consequence of strong thermodynamic coupling is that equilibration trajectories are serpentine in shape and may exhibit incursions into meta-stable zones opening up the possibility of spontaneous emulsification and the Ouzo effect. If diffusional coupling effects are ignored, the equilibration trajectory is linear in composition space. For a wide variety of partially miscible ternary mixtures, it is demonstrated that the corresponding linear equilibration trajectories do not anticipate the possibility of emulsification.

  20. Comparing bottom-up and top-down parameterisations of a process-based runoff generation model tailored on floods

    NASA Astrophysics Data System (ADS)

    Antonetti, Manuel; Scherrer, Simon; Margreth, Michael; Zappa, Massimiliano

    2016-04-01

    Information about the spatial distribution of dominant runoff processes (DRPs) can improve flood predictions on ungauged basins, where conceptual rainfall-runoff models usually appear to be limited due to the need for calibration. For example, hydrological classifications based on DRPs can be used as regionalisation tools assuming that, once a model structure and its parameters have been identified for each DRP, they can be transferred to other areas where the same DRP occurs. Here we present a process-based runoff generation model as an event-based spin-off of the conceptual hydrological model PREVAH. The model is grid-based and consists of a specific storage system for each DRP. To unbind the parameter values from catchment-related characteristics, the runoff concentration and the flood routing are uncoupled from the runoff generation routine and simulated separately. For the model parameterisation, two contrasting approaches are applied. First, in a bottom-up approach, the parameters of the runoff generation routine are determined a priori based on the results of sprinkling experiments on 60-100 m2 hillslope plots at several grassland locations in Switzerland. The model is, then, applied on a small catchment (0.5 km2) on the Swiss Plateau, and the parameters linked to the runoff concentration are calibrated on a single heavy rainfall-runoff event. The whole system is finally verified on several nearby catchments of larger sizes (up to 430 km2) affected by different heavy rainfall events. In a second attempt, following a top-down approach, all the parameters are calibrated on the largest catchment under investigation and successively verified on three sub-catchments. Simulation results from both parameterisation techniques are finally compared with results obtained with the traditional PREVAH.

  1. 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.

  2. Dissolution behavior of a miscible polymer blend

    SciTech Connect

    Rodriguez, F.

    1996-12-31

    The orderly dissolution process with minimal swelling exhibited by poly(methyl methacrylate), PMMA, also is preserved in some blends of PMMA with other polymers. In the present work, dissolution rates for blends with up to 30 % poly(epichlorohydrin), PECH, have been measured in 4-methyl-2-pentanone at temperatures of 20 to 40{degrees}C. For films in the thickness range of 0.5 to 1 {mu}m, a laser interferometer yielded both the rate and the presence or absence of a transition layer at the polymer-solvent interface. The dissolution rate increases monotonically as the amount of PECH is increased. Beyond about 40% PECH, the dissolution process becomes less orderly. When a laser beam is reflected from a flat polymer film on a reflecting substrate like silicon, the reflected light intensity takes the form of a sinusoidal (or nearly sinusoidal) oscillation. The period of the oscillation can be related to the rate of dissolution. The amplitude of the oscillations gives a direct measure of refractive index of the polymer film. Changes in the amplitude (and, sometimes, the rate) give information about swelling. The offset between the maximum in the oscillations during dissolution compared to the reflectance of the bare wafer can be converted into a transition layer thickness although it is necessary to interpose a mathematical model for the concentration gradient in the layer. The most investigated {open_quotes}well-ordered{close_quotes} polymer is poly(methylmethacrylate), PMMA. Although primarily limited to lithography using electron beams or x-rays, PMMA continues to be a valuable reference polymer for dissolution studies.

  3. Miscibility Phase Diagrams of Giant Vesicles Containing Sphingomyelin

    NASA Astrophysics Data System (ADS)

    Veatch, Sarah L.; Keller, Sarah L.

    2005-04-01

    Saturated sphingomyelin (SM) lipids are implicated in lipid rafts in cell plasma membranes. Here we use fluorescence microscopy to observe coexisting liquid domains in vesicles containing SM, an unsaturated phosphatidylcholine lipid (either DOPC or POPC), and cholesterol. We note similar phase behavior in a model membrane mixture without SM (DOPC/DPPC/Chol), but find no micron-scale liquid domains in membranes of POPC/PSM/Chol. We delineate the onset of solid phases below the miscibility transition temperature, and detail indirect evidence for a three-phase coexistence of one solid and two liquid phases.

  4. Investigating the role of geology in the hydrological response of Mediterranean catchments prone to flash-floods: Regional modelling study and process understanding

    NASA Astrophysics Data System (ADS)

    Vannier, Olivier; Anquetin, Sandrine; Braud, Isabelle

    2016-10-01

    In this study, a regional distributed hydrological model is used to perform long-term and flash-flood event simulations, over the Cévennes-Vivarais region (south of France). The objective is to improve our understanding on the role played by geology on the hydrological processes of catchments during two past flash-flood events. This modelling work is based on Vannier et al. ("Regional estimation of catchment-scale soil properties by means of streamflow recession analysis for use in distributed hydrological models", Hydrological Processes, 2014), where streamflow recessions are analysed to estimate the thickness and hydraulic conductivity of weathered rock layers, depending on the geological nature of catchments. Weathered rock layers are thus implemented into the hydrological model CVN-p, and the contribution of these layers is assessed during flash-flood events simulations as well as during inter-event periods. The model is used without any calibration, to test hypotheses on the active hydrological processes. The results point out two different hydrological behaviours, depending on the geology: on crystalline rocks (granite and gneiss), the addition of a weathered rock layer considerably improves the simulated discharges, during flash-flood events as well as during recession periods, and makes the model able to remarkably reproduce the observed streamflow dynamics. For other geologies (schists especially), the benefits are real, but not sufficient to properly simulate the observed streamflow dynamics. These results probably underline the existence of poorly known processes (flow paths, non-linear spilling process) associated with the planar structure of schisty rocks. On a methodological point of view, this study proposes a simple way to account for the additional storage associated with each geological entity, through the addition of a weathered porous rock layer situated below the traditionally-considered upper soil horizons, and shows its applicability and

  5. Distillation Column Flooding Predictor

    SciTech Connect

    George E. Dzyacky

    2010-11-23

    /vapor traffic that produce increased contact area and lead to substantial increases in separation efficiency – which translates to a 10% increase in energy efficiency on a BTU/bbl basis. The Flooding Predictor™ operates on the principle that between five to sixty minutes in advance of a flooding event, certain column variables experience an oscillation, a pre-flood pattern. The pattern recognition system of the Flooding Predictor™ utilizes the mathematical first derivative of certain column variables to identify the column’s pre-flood pattern(s). This pattern is a very brief, highly repeatable, simultaneous movement among the derivative values of certain column variables. While all column variables experience negligible random noise generated from the natural frequency of the process, subtle pre-flood patterns are revealed among sub-sets of the derivative values of column variables as the column approaches its hydraulic limit. The sub-set of column variables that comprise the pre-flood pattern is identified empirically through in a two-step process. First, 2ndpoint’s proprietary off-line analysis tool is used to mine historical data for pre-flood patterns. Second, the column is flood-tested to fine-tune the pattern recognition for commissioning. Then the Flooding Predictor™ is implemented as closed-loop advanced control strategy on the plant’s distributed control system (DCS), thus automating control of the column at its hydraulic limit.

  6. Rheological behaviors and miscibility of mixture solution of polyaniline and cellulose dissolved in an aqueous system.

    PubMed

    Shi, Xingwei; Lu, Ang; Cai, Jie; Zhang, Lina; Zhang, Hongming; Li, Ji; Wang, Xianhong

    2012-08-13

    In our previous work, supramolecular films composed of hydrophilic cellulose and hydrophobic polyaniline (PANI) dissolved in NaOH/urea aqueous solution at low temperature through rearrangement of hydrogen bonds have been constructed. To further understand the miscibility and processability of the complex solution, the dynamic rheological behaviors of the PANI/cellulose complex solution were investigated, for the first time, in the present work. Transmission electron microscope (TEM) results demonstrated that the inclusion complexes consisted of PANI and cellulose, existed in the aqueous solution, showing a good miscibility. Time-temperatures superposition (tTs) results indicated that the PANI/cellulose solution exhibited a homogeneous system, and the complex solution was more stable than the cellulose solution in the temperature range from 5 to 25 °C. Winter-Chambon theory was proved to be capable of describing the gelation behavior of the PANI/cellulose complex solution. The relaxation exponent at the gel point was calculated to be 0.74, lower than the cellulose solution, indicating strong interactions between PANI and cellulose chains. Relatively larger flow activation energy of the PANI/cellulose solution suggested the formation and rupture of linkages in "junction zones" during the gelation processes. Furthermore, PANI/cellulose gels could form at elevated temperature as a result of the physical cross-linking and chain entanglement, and it was a thermoirreversible process. Moreover, the PANI/cellulose solution remained a liquid state for a long time at the temperature range from 0 to 8 °C, which is important for the industry process.

  7. How the Image Processing Pipeline Handles the Flood of Data from Pan-STARRS 1

    NASA Astrophysics Data System (ADS)

    Flewelling, Heather

    2012-05-01

    Pan-STARRS 1 (PS-1) is a 1.8 meter telescope with a 1.4 Gigapixel camera, located in Haleakala, Hawaii. PS1's science mission began in May 2010, and roughly 500 exposures are taken each night. There are several surveys, with different requirements for image processing. The Image Processing Pipeline (IPP) is the group responsible for processing the PS1 data. The requirements to process this data is staggering. We have 138 machines, 2.3 TB of storage, and 4.4T of ram. The data is processed each night as it is taken, and is distributed to the consortium. This poster will show the different stages of processing, with various metrics showing the quality of data, time and resources needed. The PS1 Science Consortium consists of The Institute for Astronomy at the University of Hawai'i in Manoa, the Max Planck Institute for Astronomy, Heidelberg and the Max Planck Institute for Extraterrestrial Physics, Garching, The Johns Hopkins University, the University of Durham, the University of Edinburgh, the Queen's University Belfast, the Harvard-Smithsonian Center for Astrophysics, the Los Cumbres Observatory Global Telescope Network Incorporated, the National Central University of Taiwan, and NASA.

  8. 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.

  9. Self-similarity of Boussinesq Miscible Thermals: an Experimental Study

    NASA Astrophysics Data System (ADS)

    Zhao, Bing; Lai, Adrian; Law, Adrian; Adams, Eric

    2012-11-01

    The gross characteristics of fully-developed round miscible thermals have been well studied and reported to be self-similar (e.g. Scorer, 1957). However, there have been very few studies (Bond & Johari, 2005; Hart, 2008) concerning the internal structures of the thermal. Many important questions related to the interior fluid dynamics inside the thermal, including the self-similarity of the internal velocity and scalar distributions, remain outstanding. In the present study, detailed PIV and PLIF measurements were conducted in the axisymmetric plane (i.e. side view) of a negatively buoyant Boussinesq thermal to reveal the detailed internal structures, with CCD cameras that synchronized with a unique release mechanism that minimized the initial variations. Synchronized simultaneous flow visualization (with spotlights and a video camera) were also made to monitor the developmental shape of the thermal through a bottom view. The simultaneous information enabled an objective assessment of the experimental quality. The results showed that the maximum radius of the miscible thermal grows linearly with travel distance, which agrees with previous studies using dimensional analysis with self-similarity. The radius of the vortex ring is found to be expanding linearly, but surprising at a smaller growth rate that the overall thermal size. This raises a critical question whether the self-similarity with thermals truly exists or not. The results will be presented at the meeting.

  10. 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.

  11. Post Waterflood C02 Miscible Flood in Light Oil Fluvial-Dominated Deltaic Reservoirs

    SciTech Connect

    Tim Tipton

    1998-05-13

    The only remaining active well, Kuhn #14, in the Port Neches CO2 project went off production in October 1997. Production from this project is reached economic limit and the project termination began in the last quarter of 1997.

  12. Post Waterflood CO{sub 2} Miscible Flood in Light Oil Fluvial-Dominated Deltaic Reservoirs

    SciTech Connect

    1996-04-30

    Texaco terminated the CO{sub 2} purchase agreement with Cardox due to the declining production from the project during 1995. This decision was supported by the DOE and the Exploration and Production Technology Department (EPTD) who developed the model to simulate reservoir performance. Texaco is planning to continue recycling produced CO{sub 2} to recover the remaining 400 MBO from the Marg Area 1 reservoir. Currently one well is remaining on production Kuhn {number_sign}15R after the second producing well Kuhn {number_sign}38 sanded up. Changing the water and CO{sub 2} injection patterns should improve the sweep efficiency and restore production from other existing wells.

  13. Improving Gas Flooding Efficiency

    SciTech Connect

    Reid Grigg; Robert Svec; Zheng Zeng; Alexander Mikhalin; Yi Lin; Guoqiang Yin; Solomon Ampir; Rashid Kassim

    2008-03-31

    This study focuses on laboratory studies with related analytical and numerical models, as well as work with operators for field tests to enhance our understanding of and capabilities for more efficient enhanced oil recovery (EOR). Much of the work has been performed at reservoir conditions. This includes a bubble chamber and several core flood apparatus developed or modified to measure interfacial tension (IFT), critical micelle concentration (CMC), foam durability, surfactant sorption at reservoir conditions, and pressure and temperature effects on foam systems.Carbon dioxide and N{sub 2} systems have been considered, under both miscible and immiscible conditions. The injection of CO2 into brine-saturated sandstone and carbonate core results in brine saturation reduction in the range of 62 to 82% brine in the tests presented in this paper. In each test, over 90% of the reduction occurred with less than 0.5 PV of CO{sub 2} injected, with very little additional brine production after 0.5 PV of CO{sub 2} injected. Adsorption of all considered surfactant is a significant problem. Most of the effect is reversible, but the amount required for foaming is large in terms of volume and cost for all considered surfactants. Some foams increase resistance to the value beyond what is practical in the reservoir. Sandstone, limestone, and dolomite core samples were tested. Dissolution of reservoir rock and/or cement, especially carbonates, under acid conditions of CO2 injection is a potential problem in CO2 injection into geological formations. Another potential change in reservoir injectivity and productivity will be the precipitation of dissolved carbonates as the brine flows and pressure decreases. The results of this report provide methods for determining surfactant sorption and can be used to aid in the determination of surfactant requirements for reservoir use in a CO{sub 2}-foam flood for mobility control. It also provides data to be used to determine rock permeability

  14. Monitoring and Risk Identification Caused by High Water, Floods and Erosion Processes in Urban Part of Sava Riverbed

    NASA Astrophysics Data System (ADS)

    Oskoruš, D.; Miković, N.; Ljevar, I.

    2012-04-01

    Riverbed erosion and bottom deepening are part of natural fluvial processes in the upper stream of Sava River. The increasing gradient of those changes is interconnected with the level of human influence in the river basin and riverbed as well. In time period of last forty years the consequences of riverbed erosion are become serious as well as dangerous and they threaten the stability of hydro technical structures. The increasing value of flow velocity in riverbed in urban part of river section during high water level, mud and debris flow during the floods as well, is especially dangerous for old bridges. This paper contains result of velocity measurements during high waters taken by Hydrological Service of Republic Croatia, load transport monitoring during such events and cross sections in some vulnerable location. In this paper is given one example of Jakuševac railway bridge in Zagreb, heavily destroyed during high water event on the 30 March 2009., recently reconstructed by "Croatian Railways" company. Keywords: Riverbed erosion, flow velocity, mud and debris flow, risk identification, stability of bridges

  15. Flow and sediment processes in a cutoff meander of the Danube Delta during 100-year recurrent flood

    NASA Astrophysics Data System (ADS)

    Jugaru Tiron, L.; Le Coz, J.; Provansal, M.; Dutu, F.

    2009-04-01

    River training operations, such as meander cutoff, initiated for navigational purposes often lead to dramatic changes in the streamwise profiles (Hooke, 1986, Kesel, 2003; Kiss et al., 2007). Meander correction affects both the hydraulic and morphodynamical behavior of the modified branches that sedimentation occurs in time, while newly built canals usually experience degradation (Jugaru et. al, 2006). This study reports and analyzes new data on the hydrological and sedimentary processes at work during a morphogenic flood in a large modified meander (the Mahmudia meander) of the St. George branch, the southern branch of the Danube Delta. The 100-year recurrent flood that occurred in 2006 offered an exceptional opportunity for scanning different cross sections of the Mahmudia meander system by means of the emerging Doppler profiler (aDcp) technology in order to analyze the impact on sedimentation and dynamic processes in the study area. The Mahmudia study site corresponds to a vast natural meander which was cut off in 1984-1988 by an artificial canal opened to shipping. The meander correction accelerated fluxes through the artificial canal and dramatically enhanced deposition in the former meander. After his formation, the cutoff meander acted as sediment storage locations, essentially removing channel and point bar sediments from the active sediment budget of the main channel (Popa, 1997). During the one-hundred-year recurrent flood in April 2006, bathymetry, flow velocity and discharge data were acquired across several sections of both natural and artificial channels with an acoustic Doppler current profiler (aDcp Workhorse Sentinel 600 kHz, Teledyne RDI) in order to investigate the distribution of the flow and sediment and his impact on sedimentation in a channelized reach and its adjacent cutoff. The contrasting hydro-sedimentary processes at work in both channels and bifurcation/confluence nodal points are analyzed from the measured flux distribution

  16. Role of Conformation in - Interactions and Polymer/Fullerene Miscibility

    SciTech Connect

    Sumpter, Bobby G; Bucknall, David G.; Thio, Yonathan S; Gurun, Bilge; Campbell, Katie

    2011-01-01

    The origin of the miscibility between C60 fullerene and a series of phenylic vinyl polymers has been investigate using a combination of wide-angle x-ray (WAXS) and neutron (WANS) scattering and density functional theory (DFT) computational modeling. The solubility limit of the C60 in the polymers was found to increase non-linearly with increasing phenylic groups in the side-chain from 1 wt% in polystyrene (PS) to 12 wt% in poly(9-vinyl phenanthrene) (P9VPh). The DFT calculations showed that the polymer interacts with the fullerene preferentially with the phenylic groups in these vinyl polymers. However, due to the backbone these phenyl groups are unable to form the energetically favorable T-junction or planar - stacks with the fullerene, and are randomly oriented to the cage. The non-linear increase in solubility is believed to be associated with shape conformity of the three ring phenanthrene to the curvature of the fullerene.

  17. 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.

  18. Miscibility critical pressures in monolayers of ternary lipid mixtures.

    PubMed Central

    Keller, S L; Anderson, T G; McConnell, H M

    2000-01-01

    When phospholipids are mixed with cholesterol in a monolayer at an air-water interface, coexisting 2-dimensional liquid phases can be observed if the surface pressure, pi, is lower than the miscibility critical pressure, pi(c). Ternary mixtures of two phospholipid species with dihydrocholesterol have been reported to have critical pressures that are linearly proportional to the relative composition of the phospholipids. However, we report here that, if the acyl chains of the two phospholipids differ significantly in length or unsaturation, the behavior is markedly different. In this case, the critical pressure of the ternary mixture can be remarkably high, exceeding the critical pressures of the corresponding binary mixtures. High critical pressures are also seen in binary mixtures of phospholipid and dihydrocholesterol when the two acyl chains of the phospholipid differ sufficiently in length. Using regular solution theory, we interpret the elevated critical pressures of these mixtures as an attractive interaction between the phospholipid components. PMID:11023907

  19. 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.

  20. Polymer flooding

    SciTech Connect

    Littmann, W.

    1988-01-01

    This book covers all aspects of polymer flooding, an enhanced oil recovery method using water soluble polymers to increase the viscosity of flood water, for the displacement of crude oil from porous reservoir rocks. Although this method is becoming increasingly important, there is very little literature available for the engineer wishing to embark on such a project. In the past, polymer flooding was mainly the subject of research. The results of this research are spread over a vast number of single publications, making it difficult for someone who has not kept up-to-date with developments during the last 10-15 years to judge the suitability of polymer flooding to a particular field case. This book tries to fill that gap. An indispensable book for reservoir engineers, production engineers and lab. technicians within the petroleum industry.

  1. Tunable miscibility and thermalization in a spin-orbit coupled BEC

    NASA Astrophysics Data System (ADS)

    Wang, Su-Ju; Niffenegger, Robert J.; Chen, Yong P.; Greene, Chris H.

    2014-05-01

    The commonly used relation for the miscible-immiscible transition for two-component Bose-Einstein condensates is reconsidered. Our study goes beyond the Thomas-Fermi approximation by considering the kinetic energy term in mean field theory. Numerical solution of the time-dependent and time-independent Gross-Pitaevskii equations in the spin-orbit coupled BEC suggests a new phase boundary for the miscible-immiscible transition when kinetic energy becomes important. The possible implications of this kinetic energy effect on the thermalization of a binary BEC based on this miscibility transition are also discussed. This work was supported by NSF.

  2. Evolution of flood typology across Europe

    NASA Astrophysics Data System (ADS)

    Hundecha, Yeshewatesfa; Parajka, Juraj; Viglione, Alberto

    2016-04-01

    Following the frequent occurrence of severe flood events in different parts of Europe in the recent past, there has been a rise in interest in understanding the mechanisms by which the different events have been triggered and how they have been evolving over time. This study was carried out to establish the characteristics of observed flood events in the past across Europe in terms of their spatial extent and the processes leading up to the events using a process based hydrological model. To this end, daily discharge data from more than 750 stations of the Global Runoff Data Center were used to identify flood events at the stations based on a threshold method for the period 1961-2010. The identified events at the different stations were further analyzed to determine whether they form the same flood event, thereby delineating the spatial extent of the flood events. The pan-European hydrological model, E-HYPE, which runs at a daily time step, was employed to estimate a set of catchment hydrological and hydro-meteorological state variables that are relevant in the flood generating process for each of the identified spatially delineated flood events. A subsequent clustering of the events based on the simulated state variables, together with the spatial extent of the flood events, was used to identify the flood generating mechanism of each flood event. Four general flood generation mechanisms were identified: long-rain flood, short-rain flood, snowmelt flood, and rain-on-snow flood. A trend analysis was performed to investigate how the frequency of each of the flood types has changed over time. In order to investigate whether there is a regional and seasonal pattern in the dominant flood generating mechanisms, this analysis was performed separately for winter and summer seasons and three different regions of Europe: Northern, Western, and Eastern Europe. The results show a regional difference both in the dominant flood generating mechanism and the corresponding trends.

  3. Aspects of organic matter transport and processing within Savannah River Plant streams and the Savannah River flood plain swamp

    SciTech Connect

    Hauer, F.R.

    1985-06-01

    The studies were directed toward understanding; (1) the transport dynamics, storage, and retention of organic matter, (2) the processing of leaf material that enters the streams and swamp habitats of the SRP, and (3) how these factors are influenced by current or previous reactor operations at the SRP. Suspended particulate organic matter, benthic organic matter, and in-stream wood were investigated along selected reaches of Steel Creek from April 1983 to April 1984. Concentrations of organic seston ranged from 0.4 to 5.7 mg l/sup -1/. Steel Creek transported significantly higher concentrations of particulate organic matter than did either Meyers Branch or the waters at the swamp site. Seston and dissolved organic matter were investigated on Four Mile Creek, a thermal stream on the SRP, within three different reactor cycles; reactor not operating (cold flow), reactor operating in early portion of cycle (early hot flow), and reactor operating in late portion of cycle (late hot flow). Significantly higher concentrations of particulate organic matter were transported at all study sites during hot flow than during cold flow. Particulate organic matter and dissolved organic matter concentrations were investigated at twelve sampling sites to quantify input and output dynamics of organic matter to the flood plain swamp. Samples were taken biweekly from February 1983 to March 1984. Dissolved organic matter concentrations ranged from 1.3 to 9.9 mg l/sup -1/ and particulate organic matter concentrations ranged from 0.3 to 5.1 mg l/sup -1/. Leaf decomposition of three bottomland tree species was studied at six stream and four swamp sites under various temperature regimes.

  4. Flood Hazards - A National Threat

    USGS Publications Warehouse

    ,

    2006-01-01

    In the late summer of 2005, the remarkable flooding brought by Hurricane Katrina, which caused more than $200 billion in losses, constituted the costliest natural disaster in U.S. history. However, even in typical years, flooding causes billions of dollars in damage and threatens lives and property in every State. Natural processes, such as hurricanes, weather systems, and snowmelt, can cause floods. Failure of levees and dams and inadequate drainage in urban areas can also result in flooding. On average, floods kill about 140 people each year and cause $6 billion in property damage. Although loss of life to floods during the past half-century has declined, mostly because of improved warning systems, economic losses have continued to rise due to increased urbanization and coastal development.

  5. Flood Risk and Global Change: Future Prospects

    NASA Astrophysics Data System (ADS)

    Serra-Llobet, A.

    2014-12-01

    Global flood risk is increasing in response to population growth in flood-prone areas, human encroachment into natural flood paths (exacerbating flooding in areas formerly out of harm's way), and climate change (which alters variables driving floods). How will societies respond to and manage flood risk in coming decades? Analysis of flood policy evolution in the EU and US demonstrates that changes occurred in steps, in direct response to disasters. After the flood produced by the collapse of Tous Dam in 1982, Spain initiated a systematic assessment of areas of greatest flood risk and civil protection response. The devastating floods on the Elbe and elsewhere in central Europe in 2002 motivated adoption of the EU Floods Directive (2007), which requires member states to develop systematic flood risk maps (now due) and flood risk management plans (due in 2015). The flooding of New Orleans by Hurricane Katrina in 2005 resulted in a nationwide levee-safety assessment and improvements in communicating risk, but overall less fundamental change in US flood management than manifest in the EU since 2007. In the developing world, large (and increasing) concentrations of populations in low-lying floodplains, deltas, and coasts are increasingly vulnerable, and governments mostly ill-equipped to implement fundamental changes in land use to prevent future increases in exposure, nor to develop responses to the current threats. Even in the developed world, there is surprisingly little research on how well residents of flood-prone lands understand their true risk, especially when they are 'protected' by '100-year' levees. Looking ahead, researchers and decision makers should prioritize improvements in flood risk perception, river-basin-scale assessment of flood runoff processes (under current and future climate and land-use conditions) and flood management alternatives, and bridging the disconnect between national and international floodplain management policies and local land

  6. Comparative hemolytic activity of undiluted organic water-miscible solvents for intravenous and intra-arterial injection.

    PubMed

    Mottu, F; Stelling, M J; Rüfenacht, D A; Doelker, E

    2001-01-01

    In humans, nonaqueous solvents are administered intravascularly in two kinds of situations. They have been used in subcutaneous or intramuscular pharmaceutical formulations to dissolve water-insoluble drugs. The need for these vehicles had increased in recent years, since the drug development process has yielded many poorly water-soluble drugs. The use of water-miscible nonaqueous solvents in therefore one of the approaches for administering these products as reference solutions useful in formulation bioequivalence studies. The intravascular use of organic solvents has also gained importance owing to a new approach for the treatment of cerebral malformations using precipitating polymers dissolved in water-miscible organic solvents. At present, the solvent most commonly used for the liquid embolics to solubilize the polymers is dimethyl sulfoxide, which exhibits some local and hemodynamic toxicities. In order to find new, less toxic vehicles for pharmaceutical formulations for the intravenous and intra-arterial routes and for embolic materials, 13 water-miscible organic solvents currently used (diluted with water) for pharmaceutical applications, were evaluated in this study. Their hemolytic activity and the morphological changes induced when mixed with blood (1:99, 5:95, 10:90 solvent:blood) were estimated in vitro. From these data, the selected organic solvents could be subdivided into four groups depending on their hemolytic activity: very highly hemolytic solvents (ethyl lactate, dimethyl sulfoxide), highly hemolytic solvents (polyethylene glycol 200, acetone), moderately hemolytic solvents (tetrahydrofurfuryl alcohol, N-methyl-2-pyrrolidone, glycerol formal, ethanol, Solketal, glycofurol) and solvents with low hemolytic activity (propylene glycol, dimethyl isosorbide, diglyme).

  7. The Effects of Recent Floods and Geomorphic Processes on Red Ash Populations, Upper St Lawrence Estuary, Québec

    NASA Astrophysics Data System (ADS)

    Langlais, Dominique; Bégin, Yves

    1993-11-01

    Effects of recent floods on red ash ( Fraxinus pennsylvanica Marsh.) forest margins were studied along the upper St Lawrence Estuary in eastern Canada. Major floods amplified by tides left many injuries on riparian red ash trees, which allows dating of past disturbances based on stand structure and dendrochronological analysis. The formation of ice scars on stems, the development of basal sprouts, and the inhibition of population regeneration on shore, provide evidence of a recent increase in shore disturbance. Since the 1950s and especially the 1970s, a landward displacement of the tree line occurred as a result of increasing shore erosion. Usually the ice foot on the shore disintegrates in situ in April, but since the 1950s, early snow-melts in mid-winter have been causing sudden floods that raise the ice foot to the edge of the backshore forest, leaving many signs of damage. Increasing winter climatic variability since the 1950s seems responsible for such variations in flood regime.

  8. 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...

  9. Influence of Miscibility of Protein-Sugar Lyophilizates on Their Storage Stability.

    PubMed

    Mensink, Maarten A; Nethercott, Matthew J; Hinrichs, Wouter L J; van der Voort Maarschalk, Kees; Frijlink, Henderik W; Munson, Eric J; Pikal, Michael J

    2016-09-01

    For sugars to act as successful stabilizers of proteins during lyophilization and subsequent storage, they need to have several characteristics. One of them is that they need to be able to form interactions with the protein and for that miscibility is essential. To evaluate the influence of protein-sugar miscibility on protein storage stability, model protein IgG was lyophilized in the presence of various sugars of different molecular weight. By comparing solid-state nuclear magnetic resonance spectroscopy relaxation times of both protein and sugar on two different timescales, i.e., (1)H T1 and (1)H T1ρ, miscibility of the two components was established on a 2-5- and a 20-50-nm length scale, respectively, and related to protein storage stability. Smaller sugars showed better miscibility with IgG, and the tendency of IgG to aggregate during storage was lower for smaller sugars. The largest sugar performed worst and was phase separated on both length scales. Additionally, shorter protein (1)H T1 relaxation times correlated with higher aggregation rates during storage. The enzyme-linked immunosorbent assay (ELISA) assay showed overlapping effects of aggregation and chemical degradation and did not correspond as well with the miscibility. Because of the small scale at which miscibility was determined (2-5 nm) and the size of the protein domains (∼2.5 × 2.5 × 5 nm), the miscibility data give an indirect measure of interaction between protein and sugar. This reduced interaction could be the result of steric hindrance, providing a possible explanation as to why smaller sugars show better miscibility and storage stability with the protein.

  10. A database on flood and debris-flow processes in alluvial fans: a preliminary analysis aimed at evaluation of the damage

    NASA Astrophysics Data System (ADS)

    Vennari, Carmela; Santangelo, Nicoletta; Santo, Antonio; Parise, Mario

    2015-04-01

    Debris-flow and flood events cause yearly wide damages to buildings and infrastructures, and produce many casualties and fatalities. These processes are very common in Italy, affecting mainly torrential stream basins with different geological and morphological settings: in the Alpine mountain areas they are quite well analysed, whilst much less attention is generally paid in contexts such as those of the Apennines mostly due to the minor frequency of the events. Nevertheless, debris-flows and flood processes occur along many alluvial fans, have greatly contributed to their building up, and are therefore worth to be studied. Along many areas of the Southern Apennines, coalescent alluvial fans are a widespread geomorphic unit, typically located at the foot of steep slopes. In most cases these areas correspond to the more highly urbanised sectors, generally considered to be safer than the bottom valley, as concerns the direct effects from flooding. During intense storms, villages and towns built on alluvial fans may be affected by flooding and/or debris flow processes originated in the above catchment, and rapidly transferred downslope due to the steep slopes and the torrential character of the streams. This creates a very high hazard to the population and is at the origin of the severe and recurrent damage to urban settlements. Starting from the above considerations, we compiled a catalogue of flood and debris-flow events occurred in Campania Region, southern Italy, by consulting very different information sources: national and local newspapers and journals, regional historical archives, scientific literature, internet blogs. More than 350 events, occurred in Campania from 1700 to present, were collected. Information on time of occurrence and location are available for each event, with different level of accuracy, that is typically lower going back to the oldest events for which only the year or the month of occurrence of the event was identified; nevertheless, for

  11. Blend miscibility of cellulose propionate with poly(N-vinyl pyrrolidone-co-methyl methacrylate).

    PubMed

    Sugimura, Kazuki; Teramoto, Yoshikuni; Nishio, Yoshiyuki

    2013-10-15

    The blend miscibility of cellulose propionate (CP) with poly(N-vinyl pyrrolidone-co-methyl methacrylate) (P(VP-co-MMA)) was investigated. The degree of substitution (DS) of CP used ranged from 1.6 to >2.9, and samples for the vinyl polymer component were prepared in a full range of VP:MMA compositions. Through DSC analysis and solid-state (13)C NMR and FT-IR measurements, we revealed that CPs of DS<2.7 were miscible with P(VP-co-MMA)s of VP≥~10mol% on a scale within a few nanometers, in virtue of hydrogen-bonding interactions between CP-hydroxyls and VP-carbonyls. When the DS of CP exceeded 2.7, the miscibility was restricted to the polymer pairs using P(VP-co-MMA)s of VP=ca. 10-40 mol%; the scale of mixing in the blends concerned was somewhat larger (ca. 5-20 nm), however. The appearance of such a "miscibility window" was interpretable as an effect of intramolecular repulsion in the copolymer component. Results of DMA and birefringence measurements indicated that the miscible blending of CP with the vinyl polymer invited synergistic improvements in thermomechanical and optical properties of the respective constituent polymers. Additionally, it was found that the VP:MMA composition range corresponding to the miscibility window was expanded by modification of the CP component into cellulose acetate propionate.

  12. Phase-field modelling of a miscible system in spinning droplet tensiometer.

    PubMed

    Vorobev, Anatoliy; Boghi, Andrea

    2016-11-15

    The spinning drop tensiometry is used for measurements of surface tension coefficients, especially, when interfaces are characterised by low and ultra-low interfacial stresses. A droplet of lighter liquid is introduced into a rotating capillary that was initially saturated with another heavier liquid. The tube is subject to axial rotation that results in droplet's elongation along the tube's axis. The equilibrium shape of the droplet is used to determine the surface tension coefficient. In this work, the evolution of a slowly miscible droplet introduced into a spinning capillary is investigated. This technique is frequently employed for studies of the dynamics of miscible systems, even despite the fact that a strict equilibrium is never achieved in a mixture of fully miscible liquids. The numerical modelling of a miscible droplet is fulfilled on the basis of the phase-field (Cahn-Hilliard) approach. The numerical results are compared against the experimental data pursuing two objectives: (i) to verify the use of the phase-field approach as a consistent physics-based approach capable of accurate tracking of the short- and long-term evolution of miscible systems, and (ii) to estimate the values of the phenomenological parameters introduced within the phase-field approach, so making this approach a practical tool for modelling of thermohydrodynamic changes in miscible systems within various configurations.

  13. Temporal clustering of floods in Germany: Do flood-rich and flood-poor periods exist?

    NASA Astrophysics Data System (ADS)

    Merz, Bruno; Nguyen, Viet Dung; Vorogushyn, Sergiy

    2016-10-01

    The repeated occurrence of exceptional floods within a few years, such as the Rhine floods in 1993 and 1995 and the Elbe and Danube floods in 2002 and 2013, suggests that floods in Central Europe may be organized in flood-rich and flood-poor periods. This hypothesis is studied by testing the significance of temporal clustering in flood occurrence (peak-over-threshold) time series for 68 catchments across Germany for the period 1932-2005. To assess the robustness of the results, different methods are used: Firstly, the index of dispersion, which quantifies the departure from a homogeneous Poisson process, is investigated. Further, the time-variation of the flood occurrence rate is derived by non-parametric kernel implementation and the significance of clustering is evaluated via parametric and non-parametric tests. Although the methods give consistent overall results, the specific results differ considerably. Hence, we recommend applying different methods when investigating flood clustering. For flood estimation and risk management, it is of relevance to understand whether clustering changes with flood severity and time scale. To this end, clustering is assessed for different thresholds and time scales. It is found that the majority of catchments show temporal clustering at the 5% significance level for low thresholds and time scales of one to a few years. However, clustering decreases substantially with increasing threshold and time scale. We hypothesize that flood clustering in Germany is mainly caused by catchment memory effects along with intra- to inter-annual climate variability, and that decadal climate variability plays a minor role.

  14. Multifractal Flood Frequency Analysis

    NASA Astrophysics Data System (ADS)

    Tchiguirinskaia, I.; Schertzer, D.; Lovejoy, S.

    2007-12-01

    Hydrology and more generally sciences involved in water resources management, researches and technological or operational development face a fundamental difficulty: the extreme variability of hydrological fields. It clearly appears today that this variability is a function of the observation scale and yield natural hazards such as floods or droughts. The estimation of return periods for extreme precipitation and flooding events requires a model of the natural (unperturbed) statistical behaviour of the probability tails and the possible clustering (including possible long-range dependencies) of the extremes. Appropriate approaches for handling such non classical variability over wide ranges of time and space scale do exist. They are based on a fundamental property of the non-linear equations: scale invariance. Its specific framework is that of multifractals. In this framework hydrological variability builds up scale by scale leading to non-classical statistics; this provides the key element needed to better understand and predict floods. Scaling is a verifiable physical principle which can be exploited to model hydrological processes and estimate their statistics over wide ranges of space-time scales. We first present the Multifractal Flood Frequency Analysis (MFFA) tool and illustrate some results of its application to a large database (for more than 16000 selected stations over USA and Canada). We then discuss its efficiency by showing how the mean flow information - coupled with universal multifractal parametrizations with power law tails - can be used to estimate return times for extreme flood events.

  15. Damping of Quasi-stationary Waves Between Two Miscible Liquids

    NASA Technical Reports Server (NTRS)

    Duval, Walter M. B.

    2002-01-01

    Two viscous miscible liquids with an initially sharp interface oriented vertically inside a cavity become unstable against oscillatory external forcing due to Kelvin-Helmholtz instability. The instability causes growth of quasi-stationary (q-s) waves at the interface between the two liquids. We examine computationally the dynamics of a four-mode q-s wave, for a fixed energy input, when one of the components of the external forcing is suddenly ceased. The external forcing consists of a steady and oscillatory component as realizable in a microgravity environment. Results show that when there is a jump discontinuity in the oscillatory excitation that produced the four-mode q-s wave, the interface does not return to its equilibrium position, the structure of the q-s wave remains imbedded between the two fluids over a long time scale. The damping characteristics of the q-s wave from the time history of the velocity field show overdamped and critically damped response; there is no underdamped oscillation as the flow field approaches steady state. Viscous effects serve as a dissipative mechanism to effectively damp the system. The stability of the four-mode q-s wave is dependent on both a geometric length scale as well as the level of background steady acceleration.

  16. Combustion of two-component miscible droplets in reduced gravity

    NASA Technical Reports Server (NTRS)

    Shaw, Benjamin D.; Aharon, Israel; Gage, James W.; Jenkins, Andrew J.; Kahoe, Thomas J.

    1995-01-01

    This research focuses on the combustion of binary miscible droplets initially in the mm size range. Experiments are performed using the NASA Lewis 2.2 sec drop tower in Cleveland, Ohio, where mixtures of alkanes and/or alcohols are studied. The fuel components are selected to have significantly different volatilities. Initial oxygen mole fractions from about 0.15-0.5 and initial pressures from 0.2-2 atm are employed. Different inerts are used (He, CO2, Ar, N2) to change burning rates and sooting behaviors. Objectives are to observe the following: (1) Transient droplet diameters (including three-staged combustion behaviors and microexplosion; (2) Transient flow behaviors (sudden flame contraction, luminosity, extinction); and (3) Behaviors of observable soot particles. theoretical and computational research in support of this program has also been undertaken. This research includes analytical studies to determine the effects of small but nonzero gravitational levels on droplet gasification, analytical studies of hydrodynamic stability of spherically-symmetrical droplet gasification (to address the question as to whether spherically-symmetrical droplet gasification may be destabilized from capillary, i.e., Marangoni effects), and computational modeling of effects of capillary stresses on droplet gasification.

  17. Alcohol drops on miscible liquid: mixing or spreading?

    NASA Astrophysics Data System (ADS)

    Kim, Hyoungsoo; Muller, Koen; Shardt, Orest; Afkhami, Shahriar; Stone, Howard

    2016-11-01

    We studied how a sessile drop of alcohol behaves when placed on a fully miscible liquid. The dynamics of the subsequent mixing and spreading were captured by using a high-speed camera and investigated by varying parameters (e.g., surface tension, density, and viscosity). We observed that a deposited alcohol drop on a liquid bath remains as a floating lens shape, the alcohol liquid leaks out along the rim of the droplet, and it spreads axi-symmetrically along the bottom liquid interface. To visualize spreading and mixing features, we used time-resolved Particle Tacking Velocimetry and a Schlieren method. We observed a localized mixing flow at the rim of the floating droplet where the maximum flow speed is obtained, driven by a solutal Marangoni effect. Underneath the interface of the bath liquid, a viscous boundary layer develops while the alcohol liquid spreads along the radial direction. We also observed a finite quasi-steady interfacial flow velocity regime after the alcohol droplet touched the bottom liquid surface. In this regime, the flow speed linearly increases inside the floating lens, and outside the lens the flow speed decays along the r-direction with a power-law slope, Ur r - 1 / 2 . Physical arguments to support the observations will be discussed.

  18. Flood information for flood-plain planning

    USGS Publications Warehouse

    Bue, Conrad D.

    1967-01-01

    Floods are natural and normal phenomena. They are catastrophic simply because man occupies the flood plain, the highwater channel of a river. Man occupies flood plains because it is convenient and profitable to do so, but he must purchase his occupancy at a price-either sustain flood damage, or provide flood-control facilities. Although large sums of money have been, and are being, spent for flood control, flood damage continues to mount. However, neither complete flood control nor abandonment of the flood plain is practicable. Flood plains are a valuable resource and will continue to be occupied, but the nature and degree of occupancy should be compatible with the risk involved and with the degree of protection that is practicable to provide. It is primarily to meet the needs for defining the risk that the flood-inundation maps of the U.S. Geological Survey are prepared.

  19. Experimental Measurements of Longitudinal and Transverse Dispersion in Miscible Fluids with a High Viscosity and Density Contrast

    NASA Astrophysics Data System (ADS)

    Alkindi, A.; Bijeljic, B.; Muggeridge, A.

    2008-12-01

    Diffusion and advective dispersion may have a significant influence on the mixing between miscible fluids during displacement processes in porous media. This is particularly important when intimate mixing may result in important changes to the fluid behaviour. For example in oil recovery, mixing between injected and connate water will tend to reduce the efficiency of low salinity water injection. On the other hand recovery may be increased if injected gas mixes with high viscosity oil increasing its mobility. Most experimental data for longitudinal and transverse dispersion have been obtained using fluid pairs with very similar viscosities and densities. The traditional description (Perkins and Johnston, 1963) suggests that longitudinal dispersion decreases as mobility ratio increases. It also suggests that gravity will tend to reduce transverse dispersion. We provide experimental measurements of longitudinal (KL) and transverse (KT) dispersion at low Reynolds number as a function of Peclet number for the first contact miscible ethanol- glycerol fluid system flowing in a porous media formed from glass beads. These fluids have a high viscosity ratio of over 1000 and a significant density difference of 470 kg m-3. We show that both KL and KT are similar to values measured for a water-brine system but that KT is reduced when the less dense ethanol is flowing above the denser glycerol.

  20. Fast fluorescence-based microfluidic method for measuring minimum miscibility pressure of CO2 in crude oils.

    PubMed

    Nguyen, Phong; Mohaddes, Danyal; Riordon, Jason; Fadaei, Hossein; Lele, Pushan; Sinton, David

    2015-03-17

    Carbon capture, storage, and utilization has emerged as an essential technology for near-term CO2 emission control. The largest CO2 projects globally combine storage and oil recovery. The efficiency of this process relies critically on the miscibility of CO2 in crude oils at reservoir conditions. We present a microfluidic approach to quantify the minimum miscibility pressure (MMP) that leverages the inherent fluorescence of crude oils, is faster than conventional technologies, and provides quantitative, operator-independent measurements. To validate the approach, synthetic oil mixtures of known composition (pentane, hexadecane) are tested and MMP values are compared to reported values. Results differ by less than 0.5 MPa on average, in contrast to comparison between conventional methods with variations on the order of 1-2 MPa. In terms of speed, a pressure scan for a single MMP measurement required less than 30 min (with potential to be sub-10 min), in stark contrast to days or weeks with existing approaches. The method is applied to determine the MMP for Pennsylvania, West Texas, and Saudi crudes. Importantly, our fluorescence-based approach enables rapid, automated, operator-independent measurement of MMP as needed to inform the world's largest CO2 projects.

  1. Measuring miscible fluid displacement in porous media with magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Muir, Colleen E.; Petrov, Oleg V.; Romanenko, Konstantin V.; Balcom, Bruce J.

    2014-03-01

    The development of new quantitative magnetic resonance imaging (MRI) technologies open new opportunities for measurements of mass transport in porous media. The current work examines a simple miscible displacement process of H2O and D2O in porous media samples. Laboratory measurements of dispersion in porous media traditionally monitor the effluent intensity of an injected tracer. We employ MRI to obtain quantitative water saturation profiles, and to measure dispersion in rock core plugs. The saturation profiles are modeled with PHREEQC, a fluid transport modeling program. We demonstrate how independent magnetic resonance measurements can be employed to estimate three important input parameters for PHREEQC, mobile porosity, immobile porosity, and dispersivity. Bulk Carr Purcell Meiboom Gill (CPMG) T2 distribution measurements were undertaken to estimate mobile and immobile porosity. Bulk alternating-pulsed-gradient-stimulated-echo (APGSTE) measurements were undertaken to measure dispersivity. The imaging method employed, T2 mapping Spin Echo Single Point Imaging (SE-SPI), also provides information about the pore size distributions in the rock cores, and how the fluid occupancy of the pores changes during the displacement process.

  2. Study of rheological behavior and miscibility of epoxidized natural rubber modified neoprene

    NASA Astrophysics Data System (ADS)

    Chiu, Hsien-Tang; Tsai, Peir-An; Cheng, Tzu-Chi

    2006-02-01

    The Mooney viscosity, curing rates, vulcanization behavior, and the relationship between molecular motion of epoxidized natural rubber (ENR) and neoprene (CR) blends at different blending ratios have been studied. The experimental results of ENR/CR blends show that the Mooney viscosity decreased gradually. Plasticization was most pronounced at an ENR/CR ratio of 75/25 and is thus the easiest to process. Owing to the ring opening of the epoxy group of ENR, the rate of crosslink formation is much faster than that of CR at higher temperature. The vulcanized rate increased with increasing ENR content. The results indicated that 175 °C and 5 min were the optimum processing conditions for ENR/CR blends. The DMA spectra showed a single damping peak for the ENR/CR blends, which suggests that ENR and CR are miscible. As seen in the Arrhenius plot of frequency against T g, the activation energy increased with increasing ENR contents. This suggests the existence of interpenetration of these two rubber molecular networks.

  3. Flood resilience urban territories. Flood resilience urban territories.

    NASA Astrophysics Data System (ADS)

    Beraud, Hélène; Barroca, Bruno; Hubert, Gilles

    2010-05-01

    The flood's impact during the last twenty years on French territory reveals our lack of preparation towards large-extended floods which might cause the stopping of companies' activity, services, or lead to housing unavailability during several months. New Orleans' case has to exemplify us: four years after the disaster, the city still couldn't get back its dynamism. In France, more than 300 towns are flood-exposed. While these towns are the mainspring of territory's development, it is likely that the majority of them couldn't get up quickly after a large-extended flood. Therefore, to understand and improve the urban territory's resilience facing floods is a real stake for territory's development. Urban technical networks supply, unify and irrigate all urban territories' constituents. Characterizing their flood resilience can be interesting to understand better urban resilience. In this context, waste management during and after floods is completely crucial. During a flood, the waste management network can become dysfunctional (roads cut, waste storage installations or waste treatment flooded). How can the mayor respect his obligation to guarantee salubrity and security in his city? In post flood the question is even more problematic. The waste management network presents a real stake for territory's restart. After a flood, building materials, lopped-of branches, furniture, business stocks, farm stocks, mud, rubbles, animal cadavers are wet, mixed, even polluted by hydrocarbons or toxic substances. The waste's volume can be significant. Sanitary and environmental risks can be crucial. In view of this situation, waste's management in post crisis period raises a real problem. What to make of this waste? How to collect it? Where to stock it? How to process it? Who is responsible? Answering these questions is all the more strategic since this waste is the mark of disaster. Thus, cleaning will be the first population's and local actor's reflex in order to forget the

  4. Geomorphological factors of flash floods

    NASA Astrophysics Data System (ADS)

    Kuznetsova, Yulia

    2016-04-01

    Growing anthropogenic load, rise of extreme meteorological events frequency and total precipitation depth often lead to increasing danger of catastrophic fluvial processes worldwide. Flash floods are one of the most dangerous and less understood types of them. Difficulties of their study are mainly related to short duration of single events, remoteness and hard access to origin areas. Most detailed researches of flash floods focus on hydrological parameters of the flow itself and its meteorological factors. At the same time, importance of the basin geological and geomorphological structure for flash floods generation and the role they play in global sediment redistribution is yet poorly understood. However, understanding and quantitative assessment of these features is a real basis for a complete concept of factors, characteristics and dynamics of flash floods. This work is a review of published data on flash floods, and focuses on the geomorphological factors of the phenomenon. We consider both individual roles and interactions between different geomorphological features (the whole basin parameters, characteristics of the single slopes and valley bottom). Special attention is paid to critical values of certain factors. This approach also highlights the gaps or less studied factors of flash floods. Finally, all data is organized into a complex diagram that may be used for flash floods modeling. This also may help to reach a new level of flash flood predictions and risk assessment.

  5. Effects of Land-Cover Change, Floods, and Stream Position on Geomorphic Processes - Implications for Restoration Activities

    USGS Publications Warehouse

    Fitzpatrick, F.A.; ,

    2001-01-01

    A geomorphic study for North Fish Creek, a northern Wisconsin tributary to Lake Superior was analyzed to determine the hydrologic and geomorphic changes caused by clear-cut logging and agricultural activity. Discharge magnitude estimated with HEC-2 for full-channel capacities indicate that modern full-channel discharges are about twice as large as pre-1946 full-channel discharges. Flood-plain deposition rates were high along the transitional main stem after European settlement. Restoration and protection activities would be most effective if focused on watershed practices to reduce runoff and on channel restoration that reduce buff and bank erosion in the upper and transitional main stems.

  6. Quantifying Floods of a Flood Regime in Space and Time

    NASA Astrophysics Data System (ADS)

    Whipple, A. A.; Fleenor, W. E.; Viers, J. H.

    2015-12-01

    Interaction between a flood hydrograph and floodplain topography results in spatially and temporally variable conditions important for ecosystem process and function. Individual floods whose frequency and dimensionality comprise a river's flood regime contribute to that variability and in aggregate are important drivers of floodplain ecosystems. Across the globe, water management actions, land use changes as well as hydroclimatic change associated with climate change have profoundly affected natural flood regimes and their expression within the floodplain landscape. Homogenization of riverscapes has degraded once highly diverse and productive ecosystems. Improved understanding of the range of flood conditions and spatial variability within floodplains, or hydrospatial conditions, is needed to improve water and land management and restoration activities to support the variable conditions under which species adapted. This research quantifies the flood regime of a floodplain site undergoing restoration through levee breaching along the lower Cosumnes River of California. One of the few lowland alluvial rivers of California with an unregulated hydrograph and regular floodplain connectivity, the Cosumnes River provides a useful test-bed for exploring river-floodplain interaction. Representative floods of the Cosumnes River are selected from previously-established flood types comprising the flood regime and applied within a 2D hydrodynamic model representing the floodplain restoration site. Model output is analyzed and synthesized to quantify and compare conditions in space and time, using metrics such as depth and velocity. This research establishes methods for quantifying a flood regime's floodplain inundation characteristics, illustrates the role of flow variability and landscape complexity in producing heterogeneous floodplain conditions, and suggests important implications for managing more ecologically functional floodplains.

  7. Tsunami flooding

    USGS Publications Warehouse

    Geist, Eric; Jones, Henry; McBride, Mark; Fedors, Randy

    2013-01-01

    Panel 5 focused on tsunami flooding with an emphasis on Probabilistic Tsunami Hazard Analysis (PTHA) as derived from its counterpart, Probabilistic Seismic Hazard Analysis (PSHA) that determines seismic ground-motion hazards. The Panel reviewed current practices in PTHA and determined the viability of extending the analysis to extreme design probabilities (i.e., 10-4 to 10-6). In addition to earthquake sources for tsunamis, PTHA for extreme events necessitates the inclusion of tsunamis generated by submarine landslides, and treatment of the large attendant uncertainty in source characterization and recurrence rates. Tsunamis can be caused by local and distant earthquakes, landslides, volcanism, and asteroid/meteorite impacts. Coastal flooding caused by storm surges and seiches is covered in Panel 7. Tsunamis directly tied to earthquakes, the similarities with (and path forward offered by) the PSHA approach for PTHA, and especially submarine landslide tsunamis were a particular focus of Panel 5.

  8. A diffuse interface approach to injection-driven flow of different miscibility in heterogeneous porous media

    NASA Astrophysics Data System (ADS)

    Chen, Ching-Yao; Yan, Pei-Yu

    2015-08-01

    Miscible and immiscible injection flows in heterogeneous porous media, for which the permeability is characterized by a log Gaussian distribution, are simulated by a robust diffuse-interface formulation. The robust numerical method enables direct qualitative and quantitative comparisons regarding pattern formations in various fluid miscibility conditions. For miscible injections, the typical size of fingering structures depends strongly on the correlation length and forms tapered fingers with sharper tips. On the other hand, the typical size of immiscible fingers is affected less significantly by the permeability heterogeneity, and wide spreading tips are retained in the fingering patterns. Prominence of fingering instability is quantitatively evaluated by the channeling width and the interfacial length. The channeling width shows strong and monotonic dependences on the heterogeneous variance. On the contrary, maximum channeling width occurs at intermediate correlation length due to local resonant effect between the faster penetrating fingers and permeability heterogeneity. On the other hand, effects of the correlation length and the permeability variance on the interfacial lengths are generally consistent. Longer interfacial length is perturbed by smaller correlation length or higher variance. Interesting invariant evolutions of interfacial lengths are revealed regardless of the permeability variance in sufficiently large correlation length under all miscibility conditions. In addition, the regime of slower growth of interfacial length at later times experimentally observed in homogeneous miscible injection is verified in heterogeneous porous media as well.

  9. Miscibility of eudragit/chitosan polymer blend in water determined by physical property measurements.

    PubMed

    Haque, Sk Ershadul; Sheela, A

    2013-01-30

    The interest in the preparation and application of polymeric blends is growing since they can exhibit properties of great industrial interest. The current study focuses on the preparation of polymeric blends of varying compositions of eudragit and chitosan and their miscibility studies. The preparation was carried out by using ethanol and 1% acetic acid in water. FT-IR spectra reveal the possibilities of chemical interactions between eudragit/chitosan. The miscibility of polymeric blend at different composition has been investigated by viscosity, ultrasonic velocity, density, refractive index and adiabatic compressibility values measured at two different temperatures 30 °C and 40 °C. The interaction parameters ΔB, μ and α, were determined from viscosity data. From the values observed, it is found that the blend is miscible in all compositions at 30 °C whereas at 40 °C, it seems to be immiscible in certain compositions. It is found that the blend is miscible, when the chitosan concentration is more than 70% (v/v) at both the temperatures and also observed that variation of temperature has no effect on the miscibility of eudragit/chitosan blend.

  10. The Miscibility of PCBM in Low Band-Gap Conjugated Polymers in Organic Photovoltaics

    NASA Astrophysics Data System (ADS)

    Chen, Huipeng; You, Wei; Peet, Jeff; Azoulay, Jason; Bazan, Guillermo; Dadmun, Mark

    2012-02-01

    Understanding the morphology of the photoactive layer in organic photovoltaics (OPVs) is essential to optimizing conjugated polymer-based solar cells to meet the targeted efficiency of 10%. The miscibility and interdiffusion of components are among the key elements that impact the development of morphology and structure in OPV active layers. This study uses neutron reflectivity to correlate the structure of low band gap polymers to their miscibility with PCBM. Several low band gap polymers that exhibit power conversion efficiencies exceeding 7%, including PBnDT-DTffBT were examined. The intermixing of low band-gap polymer and PCBM bilayers was monitored by neutron reflectivity before and after thermal annealing, providing quantification of the miscibility and interdiffusion of PCBM within the low band gap polymer layer. These results indicate that the miscibility of PCBM ranges from 3% to 26% with the low band-gap polymers studied. The correlation between low band gap polymer structure and miscibility of PCBM will also be discussed.

  11. Evaluation of some water-miscible organic solvents for spray-drying enzymes and carbohydrates.

    PubMed

    Sass, Anke; Lee, Geoffrey

    2014-06-01

    The spray-drying behaviour of 16 water-miscible organic solvents on a bench-scale machine (Büchi B290 with inert loop) was determined under mild-to-moderate process conditions, namely inlet gas temperature of 130 °C and liquid feed flow rate of ≤3 mL/min. The solvents with boiling points below the inlet gas temperature could be fully dried (Group 1 solvents). The two exceptions were DMSO and DMF which despite their higher boiling points could be fully dried. The remaining solvents with boiling points above the inlet gas temperature were not fully dried during passage through the spray-dryer (Group 2 solvents). Trypsin and lysozyme when spray-dried from Group 1 solvent binary mixtures with water showed similar inactivation and residual water content, independent of solvent. The level of residual solvent was, however, strongly dependent on solvent. Trehalose (20%) and mannitol (10%) could be spray-dried from DMSO/water binary mixtures, but the amorphous disaccharide required higher inlet gas temperature. Trehalose/trypsin and mannitol/trypsin formulations showed differing degrees of protection against enzyme inactivation when spray-dried from Group 1 solvent binary mixtures with water. In all solvents the mannitol protected as well, if not better, than the trehalose. This study identifies some suitable organic solvents for spray-drying protein formulations, but also shows the difficulties of remaining organic solvent under the moderate inlet gas temperature used.

  12. Regional flood probabilities

    USGS Publications Warehouse

    Troutman, B.M.; Karlinger, M.R.

    2003-01-01

    The T-year annual maximum flood at a site is defined to be that streamflow, that has probability 1/T of being exceeded in any given year, and for a group of sites the corresponding regional flood probability (RFP) is the probability that at least one site will experience a T-year flood in any given year. The RFP depends on the number of sites of interest and on the spatial correlation of flows among the sites. We present a Monte Carlo method for obtaining the RFP and demonstrate that spatial correlation estimates used in this method may be obtained with rank transformed data and therefore that knowledge of the at-site peak flow distribution is not necessary. We examine the extent to which the estimates depend on specification of a parametric form for the spatial correlation function, which is known to be nonstationary for peak flows. It is shown in a simulation study that use of a stationary correlation function to compute RFPs yields satisfactory estimates for certain nonstationary processes. Application of asymptotic extreme value theory is examined, and a methodology for separating channel network and rainfall effects on RFPs is suggested. A case study is presented using peak flow data from the state of Washington. For 193 sites in the Puget Sound region it is estimated that a 100-year flood will occur on the average every 4,5 years.

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

    SciTech Connect

    Dandina N. Rao

    2003-10-01

    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 reflect 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

  14. Shift in membrane miscibility transition temperature upon addition of short-chain alcohols

    NASA Astrophysics Data System (ADS)

    Schick, M.

    2016-12-01

    I consider the effect of a small concentration of a molecule, such as a short-chain alcohol, on the miscibility transition temperature of a giant plasma membrane vesicle. For concentrations sufficiently small such that the system can be treated as a dilute solution, the change in transition temperature is known to depend upon the extent of the molecule's partition into the coexisting liquid-disordered and liquid-ordered phases. Preferential partitioning into the former decreases the miscibility temperature, while preferential partitioning into the latter causes an increase. The analysis, combined with calculated values of the partition coefficient of saturated chains, illuminates the results of recent experiments on the change in miscibility transition temperatures with changing alcohol chain length, and makes several testable predictions.

  15. Drug-polymer solubility and miscibility: Stability consideration and practical challenges in amorphous solid dispersion development.

    PubMed

    Qian, Feng; Huang, Jun; Hussain, Munir A

    2010-07-01

    Drug-polymer solid dispersion has been demonstrated as a feasible approach to formulate poorly water-soluble drugs in the amorphous form, for the enhancement of dissolution rate and bioperformance. The solubility (for crystalline drug) and miscibility (for amorphous drug) in the polymer are directly related to the stabilization of amorphous drug against crystallization. Therefore, it is important for pharmaceutical scientists to rationally assess solubility and miscibility in order to select the optimal formulation (e.g., polymer type, drug loading, etc.) and recommend storage conditions, with respect to maximizing the physical stability. This commentary attempts to discuss the concepts and implications of the drug-polymer solubility and miscibility on the stabilization of solid dispersions, review recent literatures, and propose some practical strategies for the evaluation and development of such systems utilizing a working diagram.

  16. Miscibility gap in fluid dimyristoylphosphatidylcholine:cholesterol as "seen" by x rays.

    PubMed

    Richter, F; Rapp, G; Finegold, L

    2001-05-01

    A binary mixture of dimyristoylphosphatidylcholine (DMPC) and cholesterol displays a fluid miscibility gap under excess water conditions. Effects due to the imperfect miscibility of the two amphiphiles are studied near to and far from thermodynamic equilibrium by time-resolved small angle x-ray diffraction. The experiment discloses that this mixture phase separates when leaving the miscibility gap upon heating, a transition that is not included in current phase diagrams. This transition appears to be reversible and shows a temperature hysteresis of only a few degrees. We suggest a model in which the transition is driven with increasing temperature by a movement of the cholesterol away from the hydrophilic-hydrophobic interface toward the hydrophobic core of the bilayer.

  17. Effect of using miscible and immiscible healing agent on solid state self-healing system

    NASA Astrophysics Data System (ADS)

    Makenan, Siti Mastura; Jamil, Mohd Suzeren Md.

    2014-09-01

    The aim of this study is to identify the effect of using various healing agent which are miscible; poly(bisphenol-A-co-epichlorohydrin), and immiscible; poly(ethylene-co-acetate) and poly(ethylene-co-acrylic acid), on self-healing resin system. The specimens were analysed by Fourier-transform Infrared Spectrometer (FTIR), Dynamic Mechanical Thermal Analysis (DMTA), and izod test. Optical image of the sample morphology was observed using optical microscope. Healing efficiencies (HE) were evaluated using izod test. The concept of healing recovery was proved based on the use of miscible and immiscible healing agent. From the results, it can be concluded that the healable resin with miscible healing agent has the highest HE within the third healing cycle.

  18. The Effects of Branching and Deuterium Labeling on Polymer Blend Miscibility

    NASA Astrophysics Data System (ADS)

    Defelice, Jeffrey; Higgins, Julia; Lipson, Jane

    Local structural or chemical changes made to one component of a polymer blend can have a significant impact on miscibility. In this talk we will focus on several blends involving linear and 4-arm star polystyrene (PS), both hydrogenous and deuterated, and poly(vinylmethylether) (PVME). We consider the effect of the structural change on the miscibility of PS/PVME, then turn to the added effect of deuterium labeling, both on this blend and for isotopic PS mixtures. Using our Locally Correlated Lattice (LCL) model we are able to identify trends in the physical properties of pure components, such as: free volume, thermal expansion coefficient, and cohesive energy density. We find that branching and labeling, both independently and cumulatively, affect pure component properties. Our ability to correlate structural and chemical changes with trends in physical properties leads to predictions about the compatibility of pure components, and thus their blend miscibility. The authors gratefully acknowledge support from NSF DMR-1403757 and GAANN.

  19. Data mining of solubility parameters for computational prediction of drug-excipient miscibility.

    PubMed

    Alhalaweh, Amjad; Alzghoul, Ahmad; Kaialy, Waseem

    2014-07-01

    Abstract Computational data mining is of interest in the pharmaceutical arena for the analysis of massive amounts of data and to assist in the management and utilization of the data. In this study, a data mining approach was used to predict the miscibility of a drug and several excipients, using Hansen solubility parameters (HSPs) as the data set. The K-means clustering algorithm was applied to predict the miscibility of indomethacin with a set of more than 30 compounds based on their partial solubility parameters [dispersion forces (δd), polar forces (δp) and hydrogen bonding (δh)]. The miscibility of the compounds was determined experimentally, using differential scanning calorimetry (DSC), in a separate study. The results of the K-means algorithm and DSC were compared to evaluate the K-means clustering prediction performance using the HSPs three-dimensional parameters, the two-dimensional parameters such as volume-dependent solubility (δv) and hydrogen bonding (δh) and selected single (one-dimensional) parameters. Using HSPs, the prediction of miscibility by the K-means algorithm correlated well with the DSC results, with an overall accuracy of 94%. The prediction accuracy was the same (94%) when the two-dimensional parameters or the hydrogen-bonding (one-dimensional) parameter were used. The hydrogen-bonding parameter was thus a determining factor in predicting miscibility in such set of compounds, whereas the dispersive and polar parameters had only a weak correlation. The results show that data mining approach is a valuable tool for predicting drug-excipient miscibility because it is easy to use, is time and cost-effective, and is material sparing.

  20. Tuning the phase diagrams: the miscibility studies of multilactate liquid crystalline compounds

    NASA Astrophysics Data System (ADS)

    Bubnov, Alexej; Tykarska, Marzena; Hamplová, Věra; Kurp, Katarzyna

    2016-09-01

    Design of binary and multicomponent liquid crystalline mixtures is a very powerful tool to reach the desired self-assembling properties. Beyond many advantages, this method has a distinct negativity - it is very material-consuming. While working with unique chiral materials in the research laboratory, this problem can be solved by applying miscibility study by the contact preparation method. In this work, the miscibility studies of lactic acid derivatives and non-chiral/chiral liquid crystalline molecules of different structure have been done in order to establish the phase diagrams. Special attention is focused on the ferro(antiferro)electric smectic phases.

  1. Method of forming carbon dioxide mixtures miscible with formation crude oils

    SciTech Connect

    Froning, H. R.; Yellig Jr., W. F.

    1985-07-16

    A method is disclosed for forming a carbon dioxide-containing mixture which is miscible with crude oil. The method comprises maintaining a mixture of crude oil and carbon dioxide in an extraction zone at a temperature and pressure such that multiple phase equilibrium is achieved therebetween. A carbon dioxide-rich phase that includes a mixture of carbon dioxide and hydrocarbons is withdrawn and is miscible with the reservoir crude oil when injected into the reservoir from which the crude oil was produced.

  2. Miscibility study of hexanoyl chitosan in blend with epoxidized natural rubber by viscometric analysis

    NASA Astrophysics Data System (ADS)

    Jamal, Asheila; Chan, C. H.; Muhammad, F. H.; Winie, Tan

    2015-08-01

    Miscibility of blends of hexanoyl chitosan and epoxidized natural rubber with 25 mol% epoxidation level (ENR25) was investigated by dilute solution viscometry (DSV). Experimental results obey the Huggins' equation in the concentration range under investigation. Intrinsic viscosities are found to vary linearly with blend composition. The difference between experimental and ideal Huggins coefficients, κ =K12-√{K1ṡK2 } is proposed to evaluate the miscibility behavior of the blends. Negative deviations from the ideal behavior indicated immiscibility between hexanoyl chitosan and ENR25.

  3. Understanding cratonic flood basalts

    NASA Astrophysics Data System (ADS)

    Silver, Paul G.; Behn, Mark D.; Kelley, Katherine; Schmitz, Mark; Savage, Brian

    2006-05-01

    The origin of continental flood basalts has been debated for decades. These eruptions often produce millions of cubic kilometers of basalt on timescales of only a million years. Although flood basalts are found in a variety of settings, no locale is more puzzling than cratonic areas such as southern Africa or the Siberian craton, where strong, thick lithosphere is breached by these large basaltic outpourings. Conventionally, flood basalts have been interpreted as melting events produced by one of two processes: 1) elevated temperatures associated with mantle plumes and/or 2) adiabatic-decompression melting associated with lithospheric thinning. In southern Africa, however, there are severe problems with both of these mechanisms. First, the rifting circumstances of several well-known basaltic outpourings clearly reflect lithospheric control rather than the influence of a deep-seated plume. Specifically, rift timing and magmatism are correlated with stress perturbations to the lithosphere associated with the formation of collisional rifts. Second, the substantial lithospheric thinning required for adiabatic decompression melting is inconsistent with xenolith evidence for the continued survival of thick lithosphere beneath flood basalt domains. As an alternative to these models, we propose a new two-stage model that interprets cratonic flood basalts not as melting events, but as short-duration drainage events that tap previously created sublithospheric reservoirs of molten basalt formed over a longer time scale. Reservoir creation/existence (Stage I) requires long-term (e.g. ≫ 1 Ma) supersolidus conditions in the sublithospheric mantle that could be maintained by an elevated equilibrium geotherm (appropriate for the Archean), a slow thermal perturbation (e.g. thermal blanketing or large-scale mantle upwelling), or a subduction-related increase in volatile content. The drainage event (Stage II) occurs in response to an abrupt stress change in the lithosphere, which

  4. Local Flood Proofing Programs

    DTIC Science & Technology

    2005-02-01

    100-year flood. Selecting an appropriate flood protection level is discussed on page 63. Human Intervention: the need for one or more people to be...this publication, communities were asked “Why did your community select flood proofing as a damage reduction measure?” Six broad reasons were cited...Flood Proofing Programs – 10 – February 2005 External impact: Sometimes flood proofing is selected because the other flood protection measures

  5. Modelling Miscible Fluid Displacements in Porous Media Using Karhunen-Loéve Decomposition and Artificial Neural Networks

    NASA Astrophysics Data System (ADS)

    Smaoui, Nejib; Gharbi, Ridha

    2000-11-01

    An approach to model fluid displacements in porous media that combines two powerful techniques, namely Karhunen-Loéve (KL) decomposition and artificial neural networks (ANNs) is descibed. KL decomposition known, for data compression and feature identification, is used to extract coherent structures or eigenfunctions using fluid concentration maps obtained from fine-mesh numerical simulations of miscible fluid displacements of oil by solvent in a two-dimensional vertical cross-section. Twenty KL eigenfunctions that capture 98.8% of the total energy are extracted. Corresponding data coefficients are constructed by projecting the fluid concentration maps of the numerical simulations onto the KL eigenfunctions. Processing these data coefficients through an ANN is found to be a powerful tool in predicting the fluid displacements of the fine-mesh numerical simulations without actually performing these simulations.

  6. Drivers of flood damage on event level

    NASA Astrophysics Data System (ADS)

    Kreibich, Heidi

    2016-04-01

    Flood risk is dynamic and influenced by many processes related to hazard, exposure and vulnerability. Flood damage increased significantly over the past decades, however, resulting overall economic loss per event is an aggregated indicator and it is difficult to attribute causes to this increasing trend. Much has been learned about damaging processes during floods at the micro-scale, e.g. building level. However, little is known about the main factors determining the amount of flood damage on event level. Thus, we analyse and compare paired flood events, i.e. consecutive, similar damaging floods that occurred in the same area. In analogy to 'Paired catchment studies' - a well-established method in hydrology to understand how changes in land use affect streamflow - we will investigate how and why resulting flood damage in a region differed between the first and second consecutive flood events. One example are the 2002 and 2013 floods in the Elbe and Danube catchments in Germany. The 2002 flood caused the highest economic damage (EUR 11600 million) due to a natural hazard event in Germany. Damage was so high due to extreme flood hazard triggered by extreme precipitation and a high number of resulting dyke breaches. Additionally, exposure hotspots like the city of Dresden at the Elbe river as well as some smaller municipalities at the river Mulde (e.g. Grimma, Eilenburg, Bitterfeld, Dessau) were severely impacted. However, affected parties and authorities learned from the extreme flood in 2002, and many governmental flood risk programs and initiatives were launched. Considerable improvements since 2002 occurred on many levels that deal with flood risk reduction and disaster response, in particular in 1) increased flood prevention by improved spatial planning, 2) an increased number of property-level mitigation measures, 3) more effective early warning and improved coordination of disaster response and 4) a more targeted maintenance of flood defence systems and their

  7. Floods, flood control, and bottomland vegetation

    USGS Publications Warehouse

    Friedman, Jonathan M.; Auble, Gregor T.

    2000-01-01

    Bottomland plant communities are typically dominated by the effects of floods. Floods create the surfaces on which plants become established, transport seeds and nutrients, and remove establish plants. Floods provide a moisture subsidy that allows development of bottomland forests in arid regions and produce anoxic soils, which can control bottomland plant distribution in humid regions. Repeated flooding produces a mosaic of patches of different age, sediment texture, and inundation duration; this mosaic fosters high species richness.

  8. Implementing the EU Floods Directive (2007/60/EC) in Austria: Flood Risk Management Plans

    NASA Astrophysics Data System (ADS)

    Neuhold, Clemens

    2013-04-01

    he Directive 2007/60/EC of the European Parliament and of the Council of 23 October 2007 on the assessment and management of flood risks (EFD) aims at the reduction of the adverse consequences for human health, the environment, cultural heritage and economic activity associated with floods in the Community. This task is to be achieved based on three process steps (1) preliminary flood risk assessment (finalised by the end of 2011), (2) flood hazard maps and flood risk maps (due 2013) and (3) flood risk management plans (due 2015). Currently, an interdisciplinary national working group is defining the methodological framework for flood risk management plans in Austria supported by a constant exchange with international bodies and experts. Referring to the EFD the components of the flood risk management plan are (excerpt): 1. conclusions of the preliminary flood risk assessment 2. flood hazard maps and flood risk maps and the conclusions that can be drawn from those maps 3. a description of the appropriate objectives of flood risk management 4. a summary of measures and their prioritisation aiming to achieve the appropriate objectives of flood risk management The poster refers to some of the major challenges in this process, such as the legal provisions, coordination of administrative units, definition of public relations, etc. The implementation of the EFD requires the harmonisation of legal instruments of various disciplines (e.g. water management, spatial planning, civil protection) enabling a coordinated - and ideally binding - practice of flood risk management. This process is highly influenced by the administrative organisation in Austria - federal, provincial and municipality level. The Austrian approach meets this organisational framework by structuring the development of the flood risk management plan into 3 time-steps: (a) federal blueprint, (b) provincial editing and (c) federal finishing as well as reporting to the European Commission. Each time

  9. Constraints on the Cretaceous thermal event in the Transantarctic Mountains from alteration processes in Ferrar flood basalts

    NASA Astrophysics Data System (ADS)

    Molzahn, M.; Wörner, G.; Henjes-Kunst, F.; Rocholl, A.

    1999-12-01

    K-Ar and 40Ar/ 39Ar incremental-heating analyses on apophyllite formed during hydrothermal alteration of volcanic rocks from the Ferrar Supergroup in North Victoria Land, Antarctica, provide strong evidence for hydrothermal events during mid-Cretaceous time. A last event has been dated at 96.7±0.6 Ma. Variable older ages between 112 and 125 Ma are interpreted as mixed ages of hydrothermal events or may be caused by disturbances of the Ar-Ar system. The Rb-Sr isotope system of the apophyllites is not applicable to dating because a large portion of the Sr is radiogenic and because of Rb-mobility in the crystal structure. Secondary mineralogy suggests a temperature for alteration between 300° and 400°C. Assuming a normal thermal gradient, this temperature implies a burial depth of about 10 km. However, there is no evidence for such a burial of the Ferrar flood basalts. Therefore, an elevated thermal gradient in mid-Cretaceous time in combination with circulating fluids is proposed for the origin of the alteration phenomena.

  10. Scales of Natural Flood Management

    NASA Astrophysics Data System (ADS)

    Nicholson, Alex; Quinn, Paul; Owen, Gareth; Hetherington, David; Piedra Lara, Miguel; O'Donnell, Greg

    2016-04-01

    The scientific field of Natural flood Management (NFM) is receiving much attention and is now widely seen as a valid solution to sustainably manage flood risk whilst offering significant multiple benefits. However, few examples exist looking at NFM on a large scale (>10km2). Well-implemented NFM has the effect of restoring more natural catchment hydrological and sedimentological processes, which in turn can have significant flood risk and WFD benefits for catchment waterbodies. These catchment scale improvements in-turn allow more 'natural' processes to be returned to rivers and streams, creating a more resilient system. Although certain NFM interventions may appear distant and disconnected from main stem waterbodies, they will undoubtedly be contributing to WFD at the catchment waterbody scale. This paper offers examples of NFM, and explains how they can be maximised through practical design across many scales (from feature up to the whole catchment). New tools to assist in the selection of measures and their location, and to appreciate firstly, the flooding benefit at the local catchment scale and then show a Flood Impact Model that can best reflect the impacts of local changes further downstream. The tools will be discussed in the context of our most recent experiences on NFM projects including river catchments in the north east of England and in Scotland. This work has encouraged a more integrated approach to flood management planning that can use both traditional and novel NFM strategies in an effective and convincing way.

  11. Physical Processes Associated with Heavy Flooding Rainfall in Nashville, Tennessee, and Vicinity during 1-2 May 2010: The Role of an Atmospheric River and Mesoscale Convective Systems

    NASA Astrophysics Data System (ADS)

    Moore, B. J.; Neiman, P. J.; Ralph, F. M.; Barthold, F. E.

    2011-12-01

    A multi-scale analysis is conducted in order to examine the physical processes that resulted in prolonged heavy rainfall and devastating flash flooding across western and central Tennessee and Kentucky on 1-2 May 2010, during which Nashville, Tennessee, received 344.7 mm of rainfall and incurred 11 flood-related fatalities. On the synoptic scale, heavy rainfall was supported by a persistent corridor of strong water vapor transport rooted in the Tropics that was manifested as an atmospheric river (AR). This AR developed as water vapor was extracted from the eastern tropical Pacific and the Caribbean Sea and transported into the central Mississippi Valley by a strong southerly low-level jet (LLJ) positioned between a persistent lee trough along the eastern Mexico coast and a broad, stationary subtropical ridge positioned over the southeastern U.S. and the subtropical Atlantic. The AR, associated with substantial water vapor content and moderate convective available potential energy, supported the successive development of two quasi-stationary mesoscale convective systems (MCSs) on 1 May and 2 May, respectively. These MCSs were both linearly organized and exhibited back building and echo training, processes which afforded the repeated movement of convective cells over the same area of western and central Tennessee and Kentucky, resulting in a narrow band of rainfall totals of 200-400 mm. Mesoscale analyses reveal that the MCSs developed on the warm side of a slow-moving cold front and that the interaction between the southerly LLJ and convectively generated surface outflow boundaries was fundamental for repeatedly generating convection.

  12. What are the hydro-meteorological controls on flood characteristics?

    NASA Astrophysics Data System (ADS)

    Nied, Manuela; Schröter, Kai; Lüdtke, Stefan; Nguyen, Viet Dung; Merz, Bruno

    2017-02-01

    Flood events can be expressed by a variety of characteristics such as flood magnitude and extent, event duration or incurred loss. Flood estimation and management may benefit from understanding how the different flood characteristics relate to the hydrological catchment conditions preceding the event and to the meteorological conditions throughout the event. In this study, we therefore propose a methodology to investigate the hydro-meteorological controls on different flood characteristics, based on the simulation of the complete flood risk chain from the flood triggering precipitation event, through runoff generation in the catchment, flood routing and possible inundation in the river system and floodplains to flood loss. Conditional cumulative distribution functions and regression tree analysis delineate the seasonal varying flood processes and indicate that the effect of the hydrological pre-conditions, i.e. soil moisture patterns, and of the meteorological conditions, i.e. weather patterns, depends on the considered flood characteristic. The methodology is exemplified for the Elbe catchment. In this catchment, the length of the build-up period, the event duration and the number of gauges undergoing at least a 10-year flood are governed by weather patterns. The affected length and the number of gauges undergoing at least a 2-year flood are however governed by soil moisture patterns. In case of flood severity and loss, the controlling factor is less pronounced. Severity is slightly governed by soil moisture patterns whereas loss is slightly governed by weather patterns. The study highlights that flood magnitude and extent arise from different flood generation processes and concludes that soil moisture patterns as well as weather patterns are not only beneficial to inform on possible flood occurrence but also on the involved flood processes and resulting flood characteristics.

  13. Galerkin Methods for Miscible Displacement Problems with Point Sources and Sinks - Unit Mobility Ratio Case,

    DTIC Science & Technology

    In most cases of reservoir simulation , the size of the well-bore is extremely small in comparison with the size of the reservoir. For this reason...the invading and displaced fluids are equal. Keywords include: Galerkin methods, time-stepping procedures, reservoir simulation . treatment of singularities, asymptotic analysis, miscible displacement.

  14. 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...

  15. 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 ...

  16. Flooding and Schools

    ERIC Educational Resources Information Center

    National Clearinghouse for Educational Facilities, 2011

    2011-01-01

    According to the Federal Emergency Management Agency, flooding is the nation's most common natural disaster. Some floods develop slowly during an extended period of rain or in a warming trend following a heavy snow. Flash floods can occur quickly, without any visible sign of rain. Catastrophic floods are associated with burst dams and levees,…

  17. Core flooding tests to investigate the effects of IFT reduction and wettability alteration on oil recovery during MEOR process in an Iranian oil reservoir.

    PubMed

    Rabiei, Arash; Sharifinik, Milad; Niazi, Ali; Hashemi, Abdolnabi; Ayatollahi, Shahab

    2013-07-01

    Microbial enhanced oil recovery (MEOR) refers to the process of using bacterial activities for more oil recovery from oil reservoirs mainly by interfacial tension reduction and wettability alteration mechanisms. Investigating the impact of these two mechanisms on enhanced oil recovery during MEOR process is the main objective of this work. Different analytical methods such as oil spreading and surface activity measurements were utilized to screen the biosurfactant-producing bacteria isolated from the brine of a specific oil reservoir located in the southwest of Iran. The isolates identified by 16S rDNA and biochemical analysis as Enterobacter cloacae (Persian Type Culture Collection (PTCC) 1798) and Enterobacter hormaechei (PTCC 1799) produce 1.53 g/l of biosurfactant. The produced biosurfactant caused substantial surface tension reduction of the growth medium and interfacial tension reduction between oil and brine to 31 and 3.2 mN/m from the original value of 72 and 29 mN/m, respectively. A novel set of core flooding tests, including in situ and ex situ scenarios, was designed to explore the potential of the isolated consortium as an agent for MEOR process. Besides, the individual effects of wettability alteration and IFT reduction on oil recovery efficiency by this process were investigated. The results show that the wettability alteration of the reservoir rock toward neutrally wet condition in the course of the adsorption of bacteria cells and biofilm formation are the dominant mechanisms on the improvement of oil recovery efficiency.

  18. Designing a Flood-Risk Education Program in the Netherlands

    ERIC Educational Resources Information Center

    Bosschaart, Adwin; van der Schee, Joop; Kuiper, Wilmad

    2016-01-01

    This study focused on designing a flood-risk education program to enhance 15-year-old students' flood-risk perception. In the flood-risk education program, learning processes were modeled in such a way that the arousal of moderate levels of fear should prompt experiential and analytical information processing. In this way, understanding of flood…

  19. Visual Sensing for Urban Flood Monitoring

    PubMed Central

    Lo, Shi-Wei; Wu, Jyh-Horng; Lin, Fang-Pang; Hsu, Ching-Han

    2015-01-01

    With the increasing climatic extremes, the frequency and severity of urban flood events have intensified worldwide. In this study, image-based automated monitoring of flood formation and analyses of water level fluctuation were proposed as value-added intelligent sensing applications to turn a passive monitoring camera into a visual sensor. Combined with the proposed visual sensing method, traditional hydrological monitoring cameras have the ability to sense and analyze the local situation of flood events. This can solve the current problem that image-based flood monitoring heavily relies on continuous manned monitoring. Conventional sensing networks can only offer one-dimensional physical parameters measured by gauge sensors, whereas visual sensors can acquire dynamic image information of monitored sites and provide disaster prevention agencies with actual field information for decision-making to relieve flood hazards. The visual sensing method established in this study provides spatiotemporal information that can be used for automated remote analysis for monitoring urban floods. This paper focuses on the determination of flood formation based on image-processing techniques. The experimental results suggest that the visual sensing approach may be a reliable way for determining the water fluctuation and measuring its elevation and flood intrusion with respect to real-world coordinates. The performance of the proposed method has been confirmed; it has the capability to monitor and analyze the flood status, and therefore, it can serve as an active flood warning system. PMID:26287201

  20. Cyber surveillance for flood disasters.

    PubMed

    Lo, Shi-Wei; Wu, Jyh-Horng; Lin, Fang-Pang; Hsu, Ching-Han

    2015-01-22

    Regional heavy rainfall is usually caused by the influence of extreme weather conditions. Instant heavy rainfall often results in the flooding of rivers and the neighboring low-lying areas, which is responsible for a large number of casualties and considerable property loss. The existing precipitation forecast systems mostly focus on the analysis and forecast of large-scale areas but do not provide precise instant automatic monitoring and alert feedback for individual river areas and sections. Therefore, in this paper, we propose an easy method to automatically monitor the flood object of a specific area, based on the currently widely used remote cyber surveillance systems and image processing methods, in order to obtain instant flooding and waterlogging event feedback. The intrusion detection mode of these surveillance systems is used in this study, wherein a flood is considered a possible invasion object. Through the detection and verification of flood objects, automatic flood risk-level monitoring of specific individual river segments, as well as the automatic urban inundation detection, has become possible. The proposed method can better meet the practical needs of disaster prevention than the method of large-area forecasting. It also has several other advantages, such as flexibility in location selection, no requirement of a standard water-level ruler, and a relatively large field of view, when compared with the traditional water-level measurements using video screens. The results can offer prompt reference for appropriate disaster warning actions in small areas, making them more accurate and effective.

  1. Cyber Surveillance for Flood Disasters

    PubMed Central

    Lo, Shi-Wei; Wu, Jyh-Horng; Lin, Fang-Pang; Hsu, Ching-Han

    2015-01-01

    Regional heavy rainfall is usually caused by the influence of extreme weather conditions. Instant heavy rainfall often results in the flooding of rivers and the neighboring low-lying areas, which is responsible for a large number of casualties and considerable property loss. The existing precipitation forecast systems mostly focus on the analysis and forecast of large-scale areas but do not provide precise instant automatic monitoring and alert feedback for individual river areas and sections. Therefore, in this paper, we propose an easy method to automatically monitor the flood object of a specific area, based on the currently widely used remote cyber surveillance systems and image processing methods, in order to obtain instant flooding and waterlogging event feedback. The intrusion detection mode of these surveillance systems is used in this study, wherein a flood is considered a possible invasion object. Through the detection and verification of flood objects, automatic flood risk-level monitoring of specific individual river segments, as well as the automatic urban inundation detection, has become possible. The proposed method can better meet the practical needs of disaster prevention than the method of large-area forecasting. It also has several other advantages, such as flexibility in location selection, no requirement of a standard water-level ruler, and a relatively large field of view, when compared with the traditional water-level measurements using video screens. The results can offer prompt reference for appropriate disaster warning actions in small areas, making them more accurate and effective. PMID:25621609

  2. Flood Resilient Systems and their Application for Flood Resilient Planning

    NASA Astrophysics Data System (ADS)

    Manojlovic, N.; Gabalda, V.; Antanaskovic, D.; Gershovich, I.; Pasche, E.

    2012-04-01

    Following the paradigm shift in flood management from traditional to more integrated approaches, and considering the uncertainties of future development due to drivers such as climate change, one of the main emerging tasks of flood managers becomes the development of (flood) resilient cities. It can be achieved by application of non-structural - flood resilience measures, summarised in the 4As: assistance, alleviation, awareness and avoidance (FIAC, 2007). As a part of this strategy, the key aspect of development of resilient cities - resilient built environment can be reached by efficient application of Flood Resilience Technology (FReT) and its meaningful combination into flood resilient systems (FRS). FRS are given as [an interconnecting network of FReT which facilitates resilience (including both restorative and adaptive capacity) to flooding, addressing physical and social systems and considering different flood typologies] (SMARTeST, http://www.floodresilience.eu/). Applying the system approach (e.g. Zevenbergen, 2008), FRS can be developed at different scales from the building to the city level. Still, a matter of research is a method to define and systematise different FRS crossing those scales. Further, the decision on which resilient system is to be applied for the given conditions and given scale is a complex task, calling for utilisation of decision support tools. This process of decision-making should follow the steps of flood risk assessment (1) and development of a flood resilience plan (2) (Manojlovic et al, 2009). The key problem in (2) is how to match the input parameters that describe physical&social system and flood typology to the appropriate flood resilient system. Additionally, an open issue is how to integrate the advances in FReT and findings on its efficiency into decision support tools. This paper presents a way to define, systematise and make decisions on FRS at different scales of an urban system developed within the 7th FP Project

  3. Large-scale Flood Monitoring: Where is the most exposed to large flood in Asia?

    NASA Astrophysics Data System (ADS)

    Kwak, Y.; PARK, J.; Iwami, Y.

    2015-12-01

    Flood mapping and monitoring (particularly flood areas, locations, and durations) are an imperative process and are the fundamental part of risk management as well as emergency response. We have found that Bangladesh is the highest risk country among 14 Asian developing countries from flood risk assessment under climate change scenarios because of its largest vulnerable population to cyclic 50-year flood events. This study shows a methodological possibility to be used as a standard approach for continental-scale flood hazard and risk assessment with the use of multi-temporal Moderate Resolution Imaging Spectrometer (MODIS), a big contributor to progress in real-time hazard mapping. The purpose of this study is to detect flood inundation areas considering the flood propagation even with limitations of optical and multispectral images. We improved a water detection algorithm to achieve a better discrimination capacity to discern flood areas by using amodified land surface water index (MLSWI), and estimated flood extent areas, coupled with the water level and an optimal threshold ofMLSWI based on the spectral characteristics. In Bangladesh, the FFWC warns people that floods occur when the water level exceeds the danger level. We clearly confirmed that the flood propagation was in good agreement with the timing of the water level exceeding the water danger level in the case of the cyclic 10-year flood event. The flooding was also found to be proportional to theflood extent (areas) and duration. The results showed the novel approach's capability of providing instant,comprehensive nationwide flood mapping over the entire Bangladesh by using multi-temporal MODIS data. The ambiguities of rapid flood mapping from satellite-derived products were verified in the Brahmaputra River by using high-resolution images (ALOS AVNIR2, spatial resolution 10m), ground truth and field survey data.

  4. Radar Based Precipitation Forecasting for Flood Warning

    NASA Astrophysics Data System (ADS)

    Chen, Y.

    2007-12-01

    Precipitation is one of the most important inputs for flood warning. The accuracy of the measured precipitation controls the effectiveness of flood warning, while the forecasted precipitation increases the lead time of flood warning, this is vital for catastrophically flood warning as it provides time for flood management, such as the emergency evacuation of the people and properties within the flood prone area, so to avoid flood damages. This paper presents an algorithm for forecasting precipitation based on Chinese next generation weather radar- CINRAD for catastrophically flood warning. This algorithm includes radar data quality control, precipitation estimation and forecasting, result correction. The radar data, received at every 5-6 minutes, is quality controlled first to delete the data noises, the pre-processed radar data then is used to estimate the precipitation, which will be employed to calibrate the radar equation parameters, then the pre-processed radar data and calibrated radar equation parameters will be input to the precipitation procedure to forecast precipitation. A software based on the above algorithm is developed that can be used to forecast precipitation on real ¡§Ctime. The radar in Guangzhou city, the biggest city in southern China is studied and the precipitation in 2005 and 2006 in Liuxihe River Basin in southern China were forecasted to validate the effectiveness, the results show this algorithm is encouraging and will be put into real-time operation in the flood warning of Liuxihe River in 2007.

  5. CO{sub 2} Huff-n-Puff process in a light oil shallow shelf carbonate reservoir

    SciTech Connect

    1998-06-01

    The application of cyclic CO{sub 2}, often referred to as the CO{sub 2} Huff-n-Puff process, may find its niche in the maturing waterfloods of the Permian Basin. Coupling the CO{sub 2} H-n-P process to miscible flooding applications could provide the needed revenue to sufficiently mitigate near-term negative cash flow concerns in the capital intensive miscible projects. Texaco Exploration and Production Inc. and the US Department of Energy have teamed up in an attempt to develop the CO{sub 2} Huff-n-Puff process in the Grayburg and San Andres formations, a light oil, shallow shelf carbonate reservoir that exists throughout the Permian Basin. This cost-shared effort is intended to demonstrate the viability of this underutilized technology in a specific class of domestic reservoir. The selected site for this demonstration project is the Central Vacuum Unit waterflood in Lea County, New Mexico. The goals of the project are the development of guidelines for cost-effective selection of candidate reservoirs and wells, along with estimating recovery potential. This project has two defined budget periods. The first budget period primarily involves tasks associated with reservoir analysis and characterization, characterizing existing producibility problems, and reservoir simulation of the proposed technology. The final budget period covers the actual field demonstration of the proposed technology. Technology transfer spans the entire course of the project. This report covers the concluding tasks performed under the second budget period.

  6. BEHAVIOR OF SURFACTANT MIXTURES AT SOLID/LIQUID AND OIL/LIQUID INTERFACES IN CHEMICAL FLOODING SYSTEMS

    SciTech Connect

    P. Somasundaran

    2004-11-20

    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. 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

  7. Modeling of coalescence, agglomeration, and phase segregation in microgravity processing of bimetallic composite materials

    NASA Technical Reports Server (NTRS)

    Davis, Robert H.

    1992-01-01

    The overall objective of this research is to develop models to predict drop-size-distribution evolutions due to droplet collisions and coalescence during processing within the miscibility gap of bimetallic liquid-phase-miscibility-gap materials. The individual and collective action of gravitational and nongravitational mechanisms on the relative motion and coalescence of drops are considered.

  8. Special challenges in assessing and mapping flood risk following a flood-debris flow event

    NASA Astrophysics Data System (ADS)

    Aggett, Graeme

    2016-04-01

    Severe rainfall along the Colorado front range in 2013 delivered flood and debris flows to many mountain communities, causing millions of dollars of damage as well as taking several lives. Phase changes in clear-hyperconcentrated-debris flows during the event created challenges in recreating the hydrology post-flood and in estimating and mapping new regulatory floodplains to support ongoing flood recovery efforts. This presentation highlights approaches used to overcome these challenges and to adequately represent the different processes and their uncertainties in updated flood hazard and risk assessments. It also considers the need to educate and involve the community in this process.

  9. Flash flood awareness in southwest Virginia.

    PubMed

    Knocke, Ethan T; Kolivras, Korine N

    2007-02-01

    Flash floods are one of the most dangerous weather-related natural disasters in the world. These events develop less than six hours after a rainfall event and create hazardous situations for people and extensive damage to property. It is critical for flash flood conditions to be warned of in a timely manner to minimize impacts. There is currently a knowledge gap between flood experts and the general public about the level of perceived risk that the latter has toward the powerful flood waters and how events should be warned of, which affects the communication capabilities and efficiency of the warning process. Prior research has addressed risk perception of natural disasters, but there is little emphasis on flash floods within flood-prone regions of the United States. This research utilizes an online survey of 300 respondents to determine the current state of flash flood awareness and preparation in southwest Virginia. Analysis of trends involved the use of chi-squared tests (chi2) and simple frequency and percentage calculations. Results reveal that a knowledge base of flash floods does exist, but is not advanced enough for proper awareness. Young adults have a lower understanding and are not as concerned about flood impacts. Increased exposure and perceived risk play a key role in shaping the way a person approaches flash floods. People do monitor flood events, but they are unaware of essential guidance and communication mechanisms. Finally, results suggest that the current method of warning about flash floods is not provided at an appropriate level of detail for effective communication.

  10. Partial entrainment of gravel bars during floods

    USGS Publications Warehouse

    Konrad, C.P.; Booth, D.B.; Burges, S.J.; Montgomery, D.R.

    2002-01-01

    Spatial patterns of bed material entrainment by floods were documented at seven gravel bars using arrays of metal washers (bed tags) placed in the streambed. The observed patterns were used to test a general stochastic model that bed material entrainment is a spatially independent, random process where the probability of entrainment is uniform over a gravel bar and a function of the peak dimensionless shear stress ??*0 of the flood. The fraction of tags missing from a gravel bar during a flood, or partial entrainment, had an approximately normal distribution with respect to ??*0 with a mean value (50% of the tags entrained) of 0.085 and standard deviation of 0.022 (root-mean-square error of 0.09). Variation in partial entrainment for a given ??*0 demonstrated the effects of flow conditioning on bed strength, with lower values of partial entrainment after intermediate magnitude floods (0.065 < ??*0 < 0.08) than after higher magnitude floods. Although the probability of bed material entrainment was approximately uniform over a gravel bar during individual floods and independent from flood to flood, regions of preferential stability and instability emerged at some bars over the course of a wet season. Deviations from spatially uniform and independent bed material entrainment were most pronounced for reaches with varied flow and in consecutive floods with small to intermediate magnitudes.

  11. Miscibility gap in the U-Nd-O phase diagram: a new approach of nuclear oxides in the environment?

    PubMed

    Desgranges, L; Pontillon, Y; Matheron, P; Marcet, M; Simon, P; Guimbretière, G; Porcher, F

    2012-09-03

    To some extent, rare-earth-doped UO(2) is representative of an irradiated nuclear fuel. The two phases we observed previously in neodymium-doped UO(2) are now interpreted as the existence of a miscibility gap in the U-Nd-O phase diagram using new results obtained with Raman spectroscopy. Extrapolating the miscibility gap in the U-Nd-O phase diagram to irradiated UO(2) opens the path to a new understanding of nuclear oxides in the environment.

  12. Fluid-fluid interaction during miscible and immiscible displacement under ultrasonic waves

    NASA Astrophysics Data System (ADS)

    Hamida, T.; Babadagli, T.

    2007-12-01

    This paper aims at identifying and analyzing the influence of high-frequency, high-intensity ultrasonic radiation at the interface between immiscible (different types of oils and aqueous solutions) and miscible (different types of oil and solvent) fluids. An extensive set of Hele-Shaw type experiments were performed for several viscosity ratios, and interfacial tension. Fractal analysis techniques were applied to quantify the degree of fingering and branching. This provided a rough assessment of the degree of perturbation generated at the interface when the capillary forces along with the viscous forces are effective. Miscible Hele-Shaw experiments were also presented to isolate the effect of viscous forces. We found that ultrasound acts to stabilize the interfacial front, and that such effect is most pronounced at low viscosity ratios.

  13. Miscibility and Thermophysical Properties of Blend of Poly methyl methacrylate with Polyvinylchloride

    NASA Astrophysics Data System (ADS)

    Dixit, Manasvi; Mathur, Vishal; Baboo, Mahesh; Sharma, Kananbala; Saxena, N. S.

    2010-06-01

    The present paper reports the investigations on miscibility and thermophysical properties of blend of Poly methyl methacrylate with Polyvinylchloride, prepared by solution casting method. The miscibility of the samples is examined by dynamic mechanical analyzer (DMA) and the thermophysical properties (thermal conductivity (λ) and thermal diffusivity (χ)) have been measured using the transient plane source (TPS) technique from room temperature to 100 °C. The results of thermal transport properties of PMMA/PVC blend show an increasing trend of λ and χ upto Tg, beyond which they show a decreasing trend. The variation of thermal conductivity and diffusivity of PMMA, PVC and PMMA/PVC blend with temperature is explained on the basis of structural changes of the sample and mean free path of the phonons.

  14. Comparison of two- and three-dimensional simulations of miscible Rayleigh-Taylor instability

    SciTech Connect

    Cabot, W

    2006-02-23

    A comparison of two-dimensional and three-dimensional high-resolution numerical large-eddy simulations of planar, miscible Rayleigh-Taylor instability flows are presented. The resolution of the three-dimensional simulation is sufficient to attain a fully turbulent state. A number of different statistics from the mixing region (e.g., growth rates, PDFs, mixedness measures, and spectra) are used to demonstrate that two-dimensional flow simulations differ substantially from the three-dimensional one. It is found that the two-dimensional flow grows more quickly than its three-dimensional counterpart at late times, develops larger structures, and is much less well mixed. These findings are consistent with the concept of inverse cascade in two-dimensional flow, as well as the influence of a reduced effective Atwood number on miscible flow.

  15. 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.

  16. Flooding the Zone: A Ten-Point Approach to Assessing Critical Thinking as Part of the AACSB Accreditation Process

    ERIC Educational Resources Information Center

    Cavaliere, Frank; Mayer, Bradley W.

    2012-01-01

    Undergoing the accreditation process of the Association to Advance Collegiate Schools of Business (AACSB) can be quite daunting and stressful. It requires prodigious amounts of planning, record-keeping, and document preparation. It is not something that can be thrown together at the last minute. The same is true of the five-year reaccreditation…

  17. Effect of Chain Structure on the Miscibility of Cellulose Acetate Blends. A Small-Angle Neutron Scattering Study

    SciTech Connect

    Dyer, Caleb W.; Jiang, Zhe; Bozell, Joseph J.; Rials, Timothy G.; Heller, William T.; Dadmun, Mark D.

    2013-02-12

    The miscibility of cellulose ester blends with varying degree of substitution (DS) of acetates along the chain backbone has been investigated using small-angle neutron scattering. The difference in degree of substitution (ΔDS) between the two components in the blend was systematically varied from 0.06 to 0.63 where each blend was found to be a partially miscible, two-phase system. Miscibility between the two components initially decreases as ΔDS of the blends increases. The Flory interaction parameter, χ, concurrently increases with increasing ΔDS as a result of diminishing van der Waals forces between components. The cellulose acetates with lower degree of substitution, which contain more hydroxyl substituents, however, demonstrate greater miscibility even at higher ΔDS. This is interpreted to be the result of favorable hydrogen bonding between blend components that are possible in the presence of more hydroxyl groups. FT-IR data support this interpretation, indicating an increase in hydrogen bonding in a blend having a lower DS component. These results indicate that while an increase in structural differences between cellulose acetate blend components limits miscibility, the presence of hydroxyl groups on the chain promotes mixing. This competition accentuates the significant impact specific interactions have on blend miscibility for these copolymers.

  18. Ceramide acyl chain length markedly influences miscibility with palmitoyl sphingomyelin in bilayer membranes.

    PubMed

    Westerlund, Bodil; Grandell, Pia-Maria; Isaksson, Y Jenny E; Slotte, J Peter

    2010-07-01

    Ceramides are precursors of major sphingolipids and can be important cellular effectors. The biological effects of ceramides have been suggested to stem from their biophysical effects on membrane structure affecting the lateral and transbilayer organization of other membrane components. In this study we investigated the effect of acyl chain composition in ceramides (C4-C24:1) on their miscibility with N-palmitoyl-sphingomyelin (PSM) using differential scanning calorimetry. We found that short-chain (C4 and C8) ceramides induced phase separation and lowered the T (m) and enthalpy of the PSM endotherm. We conclude that short-chain ceramides were more miscible in the fluid-phase than in the gel-phase PSM bilayers. Long-chain ceramides induced apparent heterogeneity in the bilayers. The main PSM endotherm decreased in cooperativity and enthalpy with increasing ceramide concentration. New ceramide-enriched components could be seen in the thermograms at all ceramide concentrations above X (Cer) = 0.05. These broad components had higher T (m) values than pure PSM. C24:1 ceramide exhibited complex behavior in the PSM bilayers. The miscibility of C24:1 ceramide with PSM at low (X (Cer) = 0.05-0.10) concentrations was exceptionally good according to the cooperativity of the transition. At higher concentrations, multiple components were detected, which might have arisen from interdigitated gel-phases formed by this very asymmetric ceramide. The results of this study indicate that short-chain and long-chain ceramides have very different effects on the sphingomyelin bilayers. There also seems to be a correlation between their miscibility in binary systems and the effect of ceramides of different hydrophobic length on sphingomyelin-rich domains in multicomponent membranes.

  19. Flood mapping with multitemporal MODIS data

    NASA Astrophysics Data System (ADS)

    Son, Nguyen-Thanh; Chen, Chi-Farn; Chen, Cheng-Ru

    2014-05-01

    Flood is one of the most devastating and frequent disasters resulting in loss of human life and serve damage to infrastructure and agricultural production. Flood is phenomenal in the Mekong River Delta (MRD), Vietnam. It annually lasts from July to November. Information on spatiotemporal flood dynamics is thus important for planners to devise successful strategies for flood monitoring and mitigation of its negative effects. The main objective of this study is to develop an approach for weekly mapping flood dynamics with the Moderate Resolution Imaging Spectroradiometer data in MRD using the water fraction model (WFM). The data processed for 2009 comprises three main steps: (1) data pre-processing to construct smooth time series of the difference in the values (DVLE) between land surface water index (LSWI) and enhanced vegetation index (EVI) using the empirical mode decomposition (EMD), (2) flood derivation using WFM, and (3) accuracy assessment. The mapping results were compared with the ground reference data, which were constructed from Envisat Advanced Synthetic Aperture Radar (ASAR) data. As several error sources, including mixed-pixel problems and low-resolution bias between the mapping results and ground reference data, could lower the level of classification accuracy, the comparisons indicated satisfactory results with the overall accuracy of 80.5% and Kappa coefficient of 0.61, respectively. These results were reaffirmed by a close correlation between the MODIS-derived flood area and that of the ground reference map at the provincial level, with the correlation coefficients (R2) of 0.93. Considering the importance of remote sensing for monitoring floods and mitigating the damage caused by floods to crops and infrastructure, this study eventually leads to the realization of the value of using time-series MODIS DVLE data for weekly flood monitoring in MRD with the aid of EMD and WFM. Such an approach that could provide quantitative information on

  20. Miscibility of lubricants with refrigerants. Quarterly report, 1 April 1992--30 June 1992

    SciTech Connect

    Pate, M.B.; Zoz, S.C.; Berkenbosch, L.J.

    1992-07-01

    Miscibility data is being obtained for a variety of non-CFC refrigerants and their potential lubricants. Ten different refrigerants and seven different lubricants are being investigated. Experiments are being performed in two phases: Phase I focuses on performing screening tests and Phase II consists of developing miscibility plots. The miscibility tests are being performed in a test facility consisting of a series of miniature test cells submerged in a constant temperature bath. The bath temperature can be precisely controlled over a temperature range of -50{degrees}C to 100{degrees}C. The test cells are constructed to allow for complete visibility of lubricant-refrigerant mixtures under all test conditions. Early in this reporting period, new procedures for charging the lubricant and refrigerant into the cells for testing were adopted. All of the refrigerants and all but one of the lubricants have been received from the manufacturers. Data obtained to date includes that for R-134a, R142b, R-32, R-134, R-125, and R-143a with four lubricants, namely, two esters and two polypropylene glycols.

  1. Miscibility of sodium chloride and sodium dodecyl sulfate in the adsorbed film and aggregate.

    PubMed

    Iyota, Hidemi; Krastev, Rumen

    2009-04-01

    The adsorption, micelle formation, and salting out of sodium dodecyl sulfate in the presence of sodium chloride were studied from the viewpoint of their mixed adsorption and aggregate formation. The surface tension of aqueous solutions of a sodium chloride-sodium dodecyl sulfate mixture was measured as a function of the total molality and composition of the mixture. Phase diagrams of adsorption and aggregate formation were obtained by applying thermodynamic equations to the surface tension. Judging from the phase diagrams, sodium chloride and sodium dodecyl sulfate are miscible in the adsorbed film at very large composition of sodium chloride and in the salted-out crystalline particle, while they are immiscible in the micelle. The miscibilities in the adsorbed film, micelle, and crystalline particle increase in the following order: particle > adsorbed film > micelle. The difference in miscibility among the oriented states was ascribed to the difference in geometry between the adsorbed film and micelle and to the interaction between bilayer surfaces in the particle.

  2. Buoyancy-driven instability of a miscible horizontal displacement in a Hele-Shaw cell

    NASA Astrophysics Data System (ADS)

    Haudin, F.; Riolfo, L. A.; Knaepen, B.; de Wit, A.

    2012-11-01

    In Hele-Shaw cells, viscous fingers are forming when a fluid is injected into a more viscous one. If the two fluids are reversed, with the less mobile fluid injected into the low viscosity one, the situation is expected to be stable from a viscous point of view. Nevertheless, a destabilization of the interface can be observed due to a buoyancy-driven effect if a density difference exists between the two miscible fluids. As a result, the Poiseuille profile established in the gap of the cell locally destabilizes and convection rolls are forming. In a view from above, a striped pattern is observed at the miscible interface between the two fluids. To characterize the development of this instability, we have performed an experimental study of viscously stable miscible displacements in a Hele-Shaw cell with radial injection. The displacing fluids are aqueous solutions of glycerol and the displaced ones are either dyed water or dyed glycerol solutions. The way the relative properties of the two fluids is influencing the onset time of the instability and the characteristic size of the pattern is studied. The influence of the gap width and of the flow rate on the buoyantly unstable dynamics is also characterized.

  3. CO2 Huff-n-Puff Process in a Light Oil Shallow Shelf Carbonate Reservoir

    SciTech Connect

    Kovar, Mark; Wehner, Scott

    1998-01-13

    The application of cyclic CO2, often referred to as the CO2 Huff-n-Puff process, may find its niche in the maturing waterfloods of the Permian Basin. Coupling the CO2 Huff-n-Puff process to miscible flooding applications could provide the needed revenue to sufficiently mitigate near-term negative cash flow concerns in the capital-intensive miscible projects. Texaco Exploration & Production Inc. and the U. S. Department of Energy have teamed up in an attempt to develop the CO2 Huff-n-Puff process in the Grayburg and San Andres formations which are light oil, shallow shelf carbonate reservoirs that exist throughout the Permian Basin. This cost-shared effort is intended to demonstrate the viability of this underutilized technology in a specific class of domestic reservoir. A significant amount of oil reserves are located in carbonate reservoirs. Specifically, the carbonates deposited in shallow shelf (SSC) environments make up the largest percentage of known reservoirs within the Permian Basin of North America. Many of these known resources have been under waterflooding operations for decades and are at risk of abandonment if crude oil recoveries cannot be economically enhanced. The selected sites for this demonstration project are the Central Vacuum Unit waterflood in Lea County, New Mexico and the Sundown Slaughter Field in Hockley County, Texas. Miscible CO2 flooding is the process of choice for enhancing recovery of light oils and already accounts for over 12% of the Permian Basin's daily production. There are significant probable reserves associated with future miscible CO2 projects. However, many are marginally economic at current market conditions due to large up-front capital commitments for a peak response, which may be several years in the future. The resulting negative cash-flow is sometimes too much for an operator to absorb. The CO2 Huff-n-Puff process is being investigated as a near

  4. Characterization of remarkable floods in France, a transdisciplinary approach applied on generalized floods of January 1910

    NASA Astrophysics Data System (ADS)

    Boudou, Martin; Lang, Michel; Vinet, Freddy; Coeur, Denis

    2014-05-01

    The 2007 Flood Directive promotes the integration and valorization of historical and significant floods in flood risk management (Flood Directive Text, chapter II, and article 4). Taking into account extreme past floods analysis seems necessary in the mitigation process of vulnerability face to flooding risk. In France, this aspect of the Directive was carried out through the elaboration of Preliminary Flood Risk Assessment (PFRA) and the establishment of a 2000 floods list. From this first list, a sample of 176 floods, considered as remarkable has been selected. These floods were compiled in discussion with local authorities in charge of flood management (Lang et al., 2012) and have to be integrated in priority in local risk management policies. However, a consideration emerges about this classification: how a remarkable flood can be defined? According which criteria can it be considered as remarkable? To answer these questions, a methodology has been established by building an evaluation grid of remarkable floods in France. The primary objective of this grid is to analyze the remarkable flood's characteristics (hydrological and meteorological characteristics, sociological- political and economic impacts), and secondly to propose a classification of significant floods selected in the 2011 PFRA. To elaborate this evaluation grid, several issues had to be taken into account. First, the objective is to allow the comparison of events from various periods. These temporal disparities include the integration of various kinds of data and point out the importance of historical hydrology. It is possible to evaluate accurately the characteristics of recent floods by interpreting quantitative data (for example hydrological records. However, for floods that occurred before the 1960's it is necessary resorting to qualitative information such as written sources is necessary (Coeur, Lang, 2008). In a second part the evaluation grid requires equitable criteria in order not to

  5. CO2 Huff-n-Puff process in a light oil shallow shelf carbonate reservoir. Annual report, January 1, 1995--December 31, 1995

    SciTech Connect

    Wehner, S.C.; Boomer, R.J.; Cole, R.; Preiditus, J.; Vogt, J.

    1996-09-01

    The application of cyclic CO{sub 2}, often referred to as the CO{sub 2} Huff-n-Puff process, may find its niche in the maturing waterfloods of the Permian Basin. Coupling the CO{sub 2} H-n-P process to miscible flooding applications could provide the needed revenue to sufficiently mitigate near-term negative cash flow concerns in the capital intensive miscible projects. Texaco Exploration & Production Inc. and the U.S. Department of Energy have teamed up in an attempt to develop the CO{sub 2} Huff-n-Puff process in the Grayburg/San Andres formation; a light oil, shallow shelf carbonate reservoir within the Permian Basin. This cost-shared effort is intended to demonstrate the viability of this underutilized technology in a specific class of domestic reservoir. A significant amount of oil reserves are located in carbonate reservoirs. Specifically, the carbonates deposited in shallow shelf (SSC) environments make up the largest percentage of known reservoirs within the Permian Basin of North America. Many of these known resources have been under waterflooding operations for decades and are at risk of abandonment if crude oil recoveries cannot be economically enhanced. The selected site for this demonstration project is the Central Vacuum Unit waterflood in Lea County, New Mexico.

  6. The Hydroclimatology of Extreme Flooding in the Lower Mississippi River

    NASA Astrophysics Data System (ADS)

    Smith, James; Baeck, Mary Lynn

    2015-04-01

    The 1927 flood in the lower Mississippi River was the most destructive flood in American history, inundating more than 68,000 square kilometers of land, resulting in approximately 500 fatalities and leaving more than 700,000 people homeless. Despite the prominence of the 1927 flood, hard details on the flood, and the storms that produced the flood, are sparse. We examine the hydrometeorology, hydroclimatolgy and hydrology of the 1927 flood in the lower Mississippi River through empirical analyses of rainfall and streamflow records and through downscaling simulations of the storms that were responsible for cata-strophic flooding. We use 20th Century Reanalysis fields as boundary conditions and initial conditions for downscaling simulations with the Weather Research and Forecasting (WRF) model. We place the hydrometeorological analyses of the 1927 storms in a hydroclimatolog-ical context through analyses of the 20th Century Reanalysis fields. Analyses are designed to assess the physical processes that control the upper tail of flooding in the lower Missis-sippi River. We compare the 1927 flood in the Lower Mississippi River to floods in 2011, 1937 and 1973 that represent the most extreme flooding in the Lower Mississippi River. Our results show that extreme flooding is tied to anomalous water vapor transport linked to strength and position of the North Atlantic Subtropical High. More generally, the results are designed to provide insights to the hydroclimatology of flooding in large rivers.

  7. Floods in mountain environments: A synthesis

    NASA Astrophysics Data System (ADS)

    Stoffel, Markus; Wyżga, Bartłomiej; Marston, Richard A.

    2016-11-01

    Floods are a crucial agent of geomorphic change in the channels and valley floors of mountains watercourses. At the same time, they can be highly damaging to property, infrastructure, and life. Because of their high energy, mountain watercourses are highly vulnerable to environmental changes affecting their catchments and channels. Many factors have modified and frequently still tend to modify the environmental conditions in mountain areas, with impacts on geomorphic processes and the frequency, magnitude, and timing of floods in mountain watercourses. The ongoing climate changes vary between regions but may affect floods in mountain areas in many ways. In many mountain regions of Europe, widespread afforestation took place over the twentieth century, considerably increasing the amounts of large wood delivered to the channels and the likelihood of jamming bridges. At the same time, deforestation continues in other mountain areas, accelerating runoff and amplifying the magnitude and frequency of floods in foreland areas. In many countries, in-channel gravel mining has been a common practice during recent decades; the resultant deficit of bed material in the affected channels may suddenly manifest during flood events, resulting in the failure of scoured bridges or catastrophic channel widening. During the past century many rivers in mountain and foreland areas incised deeply; the resultant loss of floodplain water storage has decreased attenuation of flood waves, hence increasing flood hazard to downstream river reaches. On the other hand, a large amount of recent river restoration activities worldwide may provide examples of beneficial changes to flood risk, attained as a result of increased channel storage or reestablished floodplain water storage. Relations between geomorphic processes and floods operate in both directions, which means that changes in flood probability or the character of floods (e.g., increased wood load) may significantly modify the morphology

  8. Flood loss assessment in Can Tho City, Vietnam

    NASA Astrophysics Data System (ADS)

    Do, T. C.; Kreibich, H.

    2012-04-01

    Floods are recurring events in the Lower Mekong Basin resulting in loss of life and property, causing damage to agriculture and rural infrastructure, and disrupting social and economic activities. Flood management and mitigation has become a priority issue at the national and regional levels. Besides, it is expected that large areas of the Mekong delta, the Red River delta and the central coast will be flooded by sea-level rise due to climate change. Can Tho City is ranked under the five most flood-tide-influenced cities of Vietnam. It is the biggest city in the Mekong delta and it is located near the Hau river. Like other region of the Mekong delta, Can Tho suffers due to floods from upstream and flood tides from the sea. In the flood season large rural areas of the city are flooded, particularly during tidal days. Flood risk management policy includes preparative measures for living with floods and to minimise the damage caused by floods as well as to take advantage of floods for sustainable development. An intensive literature review, including administrative reports as well as expert interviews have been undertaken to gain more insight into flood characteristics, their consequences and risk mitigation. Therefore, flood damaging processes and trends have been reviewed for Can Tho City and the Mekong Basin in Vietnam. Additionally, suitable flood damage estimation methodologies have been collected as important input for flood risk analyses. On this basis it has been investigated which flood risk mitigation and management strategies promise to be effective in Can Tho City, Vietnam.

  9. Flood damage modelling: ambition and reality

    NASA Astrophysics Data System (ADS)

    Gerl, Tina; Kreibich, Heidi; Franco, Guillermo; Marechal, David; Schröter, Kai

    2015-04-01

    Flood damage modelling is of increasing importance for reliable risk assessment and management. Research efforts have improved the understanding of damaging processes and more sophisticated flood damage models have been developed. However, research seems to focus on a limited number of sectors and regions and validation of models still receives too little attention. We present a global inventory of flood damage models which is compiled from a review of scientific papers and research reports on flood damage models. The models are catalogued according to model specifications, geographical characteristics, sectors addressed, input variables used, model validation, transferability and model functions. The inventory is evaluated to position the current state of science and technology in flood damage modelling as well as to derive requirements for benchmarking damage models.

  10. 78 FR 43906 - Proposed Flood Hazard Determinations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-22

    .... Additional information regarding the SRP process can be found online at http://floodsrp.org/pdfs/srp_fact... Riverside Riverside County Flood Control County. and Water Conservation District, 1995 Market...

  11. NR/EPDM elastomeric rubber blend miscibility evaluation by two-level fractional factorial design of experiment

    NASA Astrophysics Data System (ADS)

    Razak, Jeefferie Abd; Ahmad, Sahrim Haji; Ratnam, Chantara Thevy; Mahamood, Mazlin Aida; Yaakub, Juliana; Mohamad, Noraiham

    2014-09-01

    Fractional 25 two-level factorial design of experiment (DOE) was applied to systematically prepare the NR/EPDM blend using Haake internal mixer set-up. The process model of rubber blend preparation that correlates the relationships between the mixer process input parameters and the output response of blend compatibility was developed. Model analysis of variance (ANOVA) and model fitting through curve evaluation finalized the R2 of 99.60% with proposed parametric combination of A = 30/70 NR/EPDM blend ratio; B = 70°C mixing temperature; C = 70 rpm of rotor speed; D = 5 minutes of mixing period and E = 1.30 phr EPDM-g-MAH compatibilizer addition, with overall 0.966 desirability. Model validation with small deviation at +2.09% confirmed the repeatability of the mixing strategy with valid maximum tensile strength output representing the blend miscibility. Theoretical calculation of NR/EPDM blend compatibility is also included and compared. In short, this study provides a brief insight on the utilization of DOE for experimental simplification and parameter inter-correlation studies, especially when dealing with multiple variables during elastomeric rubber blend preparation.

  12. Severe Flooding in India

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Floods devestated parts of eastern India along the Brahmaputra River in June 2000. In some tributaries of the Brahmaputra, the water reached more than 5 meters (16.5 feet) above flood stage. At least 40 residents died, and the flood waters destroyed a bridge linking the region to the rest of India. High water also threatened endangered Rhinos in Kaziranga National Park. Flooded areas are shown in red in the above image. The map was derived from Advanced Very High Resolution Radiometer (AVHRR) data taken on June 15, 2000. For more information on observing floods with satellites, see: Using Satellites to Keep our Head above Water and the Dartmouth Flood Observatory Image by the Dartmouth Flood Observatory

  13. Enhancing flood resilience through improved risk communications

    NASA Astrophysics Data System (ADS)

    O'Sullivan, J. J.; Bradford, R. A.; Bonaiuto, M.; De Dominicis, S.; Rotko, P.; Aaltonen, J.; Waylen, K.; Langan, S. J.

    2012-07-01

    A framework of guiding recommendations for effective pre-flood and flood warning communications derived from the URFlood project (2nd ERA-Net CRUE Research Funding Initiative) from extensive quantitative and qualitative research in Finland, Ireland, Italy and Scotland is presented. Eleven case studies in fluvial, pluvial, coastal, residual and "new" flood risk locations were undertaken. The recommendations were developed from questionnaire surveys by exploring statistical correlations of actions and understandings of individuals in flood risk situations to low, moderate and high resilience groupings. Groupings were based on a conceptual relationship of self-assessed levels of awareness, preparedness and worry. Focus groups and structured interviews were used to discuss barriers in flood communications, explore implementation of the recommendations and to rank the recommendations in order of perceived importance. Results indicate that the information deficit model for flood communications that relies on the provision of more and better information to mitigate risk in flood-prone areas is insufficient, and that the communications process is very much multi-dimensional. The recommendations are aimed at addressing this complexity and their careful implementation is likely to improve the penetration of flood communications. The recommendations are applicable to other risks and are transferrable to jurisdictions beyond the project countries.

  14. CO/sub 2/ flooding: its time has come

    SciTech Connect

    Holm, L.W.

    1982-12-01

    Significant increases in enhanced oil recovery projects utilizing CO/sub 2/ have been noted in the past 2 years, and CO/sub 2/ pipeline completions will bring on large field applications. Factors in selection of reservoirs for CO/sub 2/ miscible flooding are summarized. The potential for immiscible flooding can be determined by simple laboratory CO/sub 2/ solubility, swelling, and viscosity tests at reservoir conditions. Single-well minitests with logging and coring and single-well huff-n-puff field tests will provide a direct evaluation of CO/sub 2/ in a reservoir where geology, rock permeability, and other properties are not well known. CO/sub 2/ huff-n-puff has produced large quantities of heavy oil at low water-oil ratio in many field projects. It probably will be limited to relatively few fields because steam is usually more available and cheaper, and can be effective in several injection/production cycles. However, use of CO/sub 2/ huff-n-puff as a precursor to an immiscible CO/sub 2/ flood could be an efficient application of CO/sub 2/. 50 references.

  15. Final Report, Distillation Column Flooding Predictor

    SciTech Connect

    George E. Dzyacky

    2003-05-31

    The Flooding Predictor is an advanced process control strategy comprising a patented pattern-recognition methodology that identifies pre-flood patterns discovered to precede flooding events in distillation columns. The grantee holds a U.S. patent on the modeling system. The technology was validated at the Separations Research Program, The University of Texas at Austin under a grant from the U. S. Department of Energy, Inventions & Innovation Program. Distillation tower flooding occurs at abnormally high vapor and/or liquid rates. The loss in tray efficiencies is attributed to unusual behavior of liquid inventories inside the column leading to conditions of flooding of the space in between trays with liquid. Depending on the severity of the flood condition, consequences range from off spec products to equipment damage and tower shutdown. This non-intrusive pattern recognition methodology, processes signal data obtained from existing column instrumentation. Once the pattern is identified empirically, it is modeled and coded into the plant's distributed control system. The control system is programmed to briefly "unload" the tower each time the pattern appears. The unloading takes the form of a momentary reduction in column severity, e.g., decrease bottom temperature, reflux or tower throughput. Unloading the tower briefly at the pre-flood state causes long-term column operation to become significantly more stable - allowing an increase in throughput and/or product purity. The technology provides a wide range of value between optimization and flooding. When a distillation column is not running at capacity, it should be run in such a way ("pushed") that optimal product purity is achieved. Additional benefits include low implementation and maintenance costs, and a high level of console operator acceptance. The previous commercial applications experienced 98% uptime over a four-year period. Further, the technology is unique in its ability to distinguish between different

  16. Miscibility of hydrogen and helium mixtures at megabar pressures

    SciTech Connect

    Klepeis, J.E.; Schafer, K.J.; Barbee, T.W. III; Ross, M.

    1991-09-01

    Models of Jupiter and Saturn postulate a central rock core surrounded by a fluid mixture of hydrogen and helium. These models suggest that the mixture is undergoing phase separation in Saturn but not Jupiter. State-of-the-art total energy calculations of the enthalpy of mixing for ordered alloys of hydrogen and helium confirm that at least partial phase separation has occurred in Saturn and predict that this process has also begun in Jupiter. 15 refs., 2 figs.

  17. Phase transitions and phase miscibility of mixed particles of ammonium sulfate, toluene-derived secondary organic material, and water.

    PubMed

    Smith, Mackenzie L; You, Yuan; Kuwata, Mikinori; Bertram, Allan K; Martin, Scot T

    2013-09-12

    The phase states of atmospheric particles influence their roles in physicochemical processes related to air quality and climate. The phases of particles containing secondary organic materials (SOMs) are still uncertain, especially for SOMs produced from aromatic precursor gases. In this work, efflorescence and deliquescence phase transitions, as well as phase separation, in particles composed of toluene-derived SOM, ammonium sulfate, and water were studied by hygroscopic tandem differential mobility analysis (HTDMA) and optical microscopy. The SOM was produced in the Harvard Environmental Chamber by photo-oxidation of toluene at chamber relative humidities of <5 and 40%. The efflorescence and deliquescence relative humidities (ERH and DRH, respectively, studied by HTDMA) of ammonium sulfate decreased as the SOM organic fraction ε in the particle increased, dropping from DRH = 80% and ERH = 31% for ε = 0.0 to DRH = 58% and ERH = 0% for ε = 0.8. For ε < 0.2, the DRH and ERH to first approximation did not change with the organic volume fraction. This observation is consistent with independent behaviors for ε < 0.2 of water-infused toluene-derived SOM and aqueous ammonium sulfate, suggesting phase immiscibility between the two. Optical microscopy of particles prepared for ε = 0.12 confirmed phase separation for RH < 85%. For ε from 0.2 to 0.8, the DRH and ERH values steadily decreased, as studied by HTDMA. This result is consistent with one-phase mixing of ammonium sulfate, SOM, and water. Optical microscopy for particles of ε = 0.8 confirmed this result. Within error, increased exposure times of the aerosol in the HTDMA from 0.5 to 30 s affected neither the ERH(ε) nor DRH(ε) curves, implying an absence of kinetic effects on the observations over the studied time scales. For ε > 0.5, the DRH values of ammonium sulfate in mixtures with SOM produced at <5% RH were offset by -3 to -5% RH compared to the results for SOM produced at 40% RH, suggesting differences

  18. Using of Hydrodynamic Model for the Support of Decision Making Process in Water Management and Flood Risk Assessment of Lower Kuban River, Russia

    NASA Astrophysics Data System (ADS)

    Ermolaeva, O.; Zeiliguer, A.; Buber, A.

    2009-04-01

    Hydrological conditions of Lower Kuban River watershed are extremely variable. Frequently arising floods, alternated with the periods of water shortage. The catastrophic flood events occur promptly and, commonly, there is not enough time to manage flooding by normal operation of reservoirs. The management of water releases using standard rules during high waters is not effective. There is a need to use the imitation hydrodynamic model of the river network for the flood forecasting to check all possible variants of flood development and to take the efficient decision in short time. The model of the water object, validated and calibrated on the data of observations, allows to determine the basic river parameters (discharges, levels, velocities etc.) in the operative mode and to solve the following tasks: - Protection of the settlements and agricultural areas in the floodplain; - Management of water resources during the period of water deficit. The object of modeling is the basin of Lower Kuban River, including the following parts: Krasnodarskoe, Shapsugskoe, Krjukovskoe, Varnavinskoe reservoirs, Fedorovskij and Tikhovskij hydrounits, Lower Kuban River and it's branch Protoka from Krasnodar hydrosystem up to the Azov Sea, Krjukovsky connecting channel and Varnavinskij release channel, adjusted to left tributaries of Zakubanskij area together with Krjukovskoe and Varnavinskoe reservoirs. The multipurpose hydrodynamic model of system of interconnected rivers and channels at Lower Kuban River was developed with MIKE 11 package (Danish Hydraulic Institute). On its basis the special technique of water system regulation to protect agricultural areas in floodplain zone was developed. Developed approach along with authentic and regularly peer hour monitored data provide us with necessary tool for qualitative management of regulating hydraulic structures during the passage of high waters. Keywords: Flood risk assessment, MIKE 11, hydrodynamic model

  19. Historic-flood evaluation and research needs in mountainous areas

    USGS Publications Warehouse

    Jarrett, Robert D.

    1994-01-01

    An evaluation of historic flood estimates in mountainous areas in Colorado was made to assess their accuracy. The purpose of this evaluation is to enhance awareness of the need to assess the accuracy of historic flood peaks, particularly floods of record, because they are such a critical factor in flood-plain management, design of hydraulic structures in flood plains, and related environmental studies. Research needs based on a proposed river-system-process approach are suggested. A critical need exists for interdisciplinary documentation of extreme-flood processes, particularly to improve methods to directly measure extreme floods and quantify total energy losses. Such research will benefit the public through improved engineering designs and environmental investigations.

  20. Investigating miscibility and molecular mobility of nifedipine-PVP amorphous solid dispersions using solid-state NMR spectroscopy.

    PubMed

    Yuan, Xiaoda; Sperger, Diana; Munson, Eric J

    2014-01-06

    Solid-state NMR (SSNMR) (1)H T1 and T1ρ relaxation times were used to evaluate the miscibility of amorphous solid dispersions of nifedipine (NIF) and polyvinylpyrrolidone (PVP) prepared by three different methods: melt quenching in the typical lab setting, spray drying and melt quenching in the NMR rotor while spinning. Of the five compositions prepared by melt quenching in the lab setting, the 95:5 and 90:10 NIF:PVP (w:w) amorphous solid dispersions were not miscible while 75:25, 60:40, and 50:50 NIF:PVP dispersions were miscible by the (1)H T1ρ measurements. The domain size of the miscible systems was estimated to be less than 4.5 nm. Amorphous solid dispersions with composition of 90:10 NIF:PVP prepared by spray drying and melt quenching in the NMR rotor showed miscibility by (1)H T1ρ values. Variable-temperature SSNMR (1)H T1ρ relaxation measurements revealed a change in relaxation time at approximately 20 °C below Tg, suggesting increased molecular mobility above that temperature.

  1. Seasonal characteristics of flood regimes across the Alpine-Carpathian range.

    PubMed

    Parajka, J; Kohnová, S; Bálint, G; Barbuc, M; Borga, M; Claps, P; Cheval, S; Dumitrescu, A; Gaume, E; Hlavčová, K; Merz, R; Pfaundler, M; Stancalie, G; Szolgay, J; Blöschl, G

    2010-11-17

    The aim of this paper is to analyse the differences in the long-term regimes of extreme precipitation and floods across the Alpine-Carpathian range using seasonality indices and atmospheric circulation patterns to understand the main flood-producing processes. This is supported by cluster analyses to identify areas of similar flood processes, both in terms of precipitation forcing and catchment processes. The results allow to isolate regions of similar flood generation processes including southerly versus westerly circulation patterns, effects of soil moisture seasonality due to evaporation and effects of soil moisture seasonality due to snow melt. In many regions of the Alpine-Carpathian range, there is a distinct shift in flood generating processes with flood magnitude as evidenced by a shift from summer to autumn floods. It is argued that the synoptic approach proposed here is valuable in both flood analysis and flood estimation.

  2. Seasonal characteristics of flood regimes across the Alpine–Carpathian range

    PubMed Central

    Parajka, J.; Kohnová, S.; Bálint, G.; Barbuc, M.; Borga, M.; Claps, P.; Cheval, S.; Dumitrescu, A.; Gaume, E.; Hlavčová, K.; Merz, R.; Pfaundler, M.; Stancalie, G.; Szolgay, J.; Blöschl, G.

    2010-01-01

    Summary The aim of this paper is to analyse the differences in the long-term regimes of extreme precipitation and floods across the Alpine–Carpathian range using seasonality indices and atmospheric circulation patterns to understand the main flood-producing processes. This is supported by cluster analyses to identify areas of similar flood processes, both in terms of precipitation forcing and catchment processes. The results allow to isolate regions of similar flood generation processes including southerly versus westerly circulation patterns, effects of soil moisture seasonality due to evaporation and effects of soil moisture seasonality due to snow melt. In many regions of the Alpine–Carpathian range, there is a distinct shift in flood generating processes with flood magnitude as evidenced by a shift from summer to autumn floods. It is argued that the synoptic approach proposed here is valuable in both flood analysis and flood estimation. PMID:25067854

  3. Surface effects on phase distributions of a fast-quenched miscibility gap type system - Succinonitrile-water

    NASA Technical Reports Server (NTRS)

    Frazier, D. O.; Facemire, B. R.; Fanning, U. S.

    1986-01-01

    If a binary homogeneous melt is cooled into an immiscible region, the newly formed second phase will generally have a density different from the parent phase, and will separate readily by sedimentation. Observation of solidification processes in microgravity indicates that outside of sedimentation, at least two other important effets can separate the phases: (1) preferential wetting, and (2) thermal migration of second-phase droplets due to interfacial tension gradients. The latter effect would drive the minority phase along the thermal gradient toward the hottest part (assuming the interfacial tension decreases with increasing temperature), which is usually away from the crucible wall. On the other hand, if the minority phase preferentially wets the crucible, a minority phase layer which thickens as initial solution compositions approach critical, will form adjacent to the solid surface and remain in the coldest region of the ingot. This study presents compelling preliminary evidence that these two effects do exist and that they compete with one another. However, the temperature dependence of preferential wetting below T(c) for the current system of study is, as yet, undetermined. These effects are sensitive to the initial concentration of a hypermonotectic solution cooling through a miscibility gap.

  4. Miscible gravitational instability of initially stable horizontal interface in a porous medium: Non-monotonic density profiles

    NASA Astrophysics Data System (ADS)

    Kim, Min Chan

    2014-11-01

    To simulate a CO2 sequestration process, some researchers employed a water/propylene glycol (PPG) system which shows a non-monotonic density profile. Motivated by this fact, the stability of the diffusion layer of two miscible fluids saturated in a porous medium is analyzed. For a non-monotonic density profile system, linear stability equations are derived in a global domain, and then transformed into a system of ordinary differential equations in an infinite domain. Initial growth rate analysis is conducted without the quasi-steady state approximation (QSSA) and shows that initially the system is unconditionally stable for the least stable disturbance. For the time evolving case, the ordinary differential equations are solved applying the eigen-analysis and numerical shooting scheme with and without the QSSA. To support these theoretical results, direct numerical simulations are conducted using the Fourier spectral method. The results of theoretical linear stability analyses and numerical simulations validate one another. The present linear and nonlinear analyses show that the water/PPG system is more unstable than the CO2/brine one, and the flow characteristics of these two systems are quite different from each other.

  5. Past and present floods in South Moravia

    NASA Astrophysics Data System (ADS)

    Brázdil, Rudolf; Chromá, Kateřina; Řezníčková, Ladislava; Valášek, Hubert; Dolák, Lukáš; Stachoň, Zdeněk; Soukalová, Eva; Dobrovolný, Petr

    2015-04-01

    Floods represent the most destructive natural phenomena in the Czech Republic, often causing great material damage or loss of human life. Systematic instrumental measurements of water levels in Moravia (the eastern part of the Czech Republic) started mainly in the 1880s-1890s, while for discharges it was in the 1910s-1920s. Different documentary evidence allows extension of our knowledge about floods prior the instrumental period. The paper presents long-term flood chronologies for four South Moravian rivers: the Jihlava, the Svratka, the Dyje and the Morava. Different documentary data are used to extract floods. Taxation records are of particular importance among them. Since the mid-17th century, damage to property and land (fields, meadows, pastures or gardens) entitled farmers and landowners to request a tax relief. Related documents of this administration process kept mainly in Moravian Land Archives in Brno allow to obtain detail information about floods and their impacts. Selection of floods in the instrumental period is based on calculation of N-year return period of peak water levels and/or peak discharges for selected hydrological stations of the corresponding rivers (with return period of two years and more). Final flood chronologies combine floods derived from both documentary data and hydrological measurements. Despite greater inter-decadal variability, periods of higher flood frequency are c. 1821-1850 and 1921-1950 for all four rivers; for the Dyje and Morava rivers also 1891-1900. Flood frequency fluctuations are further compared with other Central European rivers. Uncertainties in created chronologies with respect to data and methods used for compilation of long-term series and anthropogenic changes in river catchments are discussed. The study is a part of the research project "Hydrometeorological extremes in Southern Moravia derived from documentary evidence" supported by the Grant Agency of the Czech Republic, reg. no. 13-19831S.

  6. Mapping technological and biophysical capacities of watersheds to regulate floods

    USGS Publications Warehouse

    Mogollon, Beatriz; Villamagna, Amy M.; Frimpong, Emmanuel A.; Angermeier, Paul

    2016-01-01

    Flood regulation is a widely valued and studied service provided by watersheds. Flood regulation benefits people directly by decreasing the socio-economic costs of flooding and indirectly by its positive impacts on cultural (e.g., fishing) and provisioning (e.g., water supply) ecosystem services. Like other regulating ecosystem services (e.g., pollination, water purification), flood regulation is often enhanced or replaced by technology, but the relative efficacy of natural versus technological features in controlling floods has scarcely been examined. In an effort to assess flood regulation capacity for selected urban watersheds in the southeastern United States, we: (1) used long-term flood records to assess relative influence of technological and biophysical indicators on flood magnitude and duration, (2) compared the widely used runoff curve number (RCN) approach for assessing the biophysical capacity to regulate floods to an alternative approach that acknowledges land cover and soil properties separately, and (3) mapped technological and biophysical flood regulation capacities based on indicator importance-values derived for flood magnitude and duration. We found that watersheds with high biophysical (via the alternative approach) and technological capacities lengthened the duration and lowered the peak of floods. We found the RCN approach yielded results opposite that expected, possibly because it confounds soil and land cover processes, particularly in urban landscapes, while our alternative approach coherently separates these processes. Mapping biophysical (via the alternative approach) and technological capacities revealed great differences among watersheds. Our study improves on previous mapping of flood regulation by (1) incorporating technological capacity, (2) providing high spatial resolution (i.e., 10-m pixel) maps of watershed capacities, and (3) deriving importance-values for selected landscape indicators. By accounting for technology that enhances

  7. αs-Casein-PE6400 mixtures: surface properties, miscibility and self-assembly.

    PubMed

    Kessler, Anne; Menéndez-Aguirre, Orquidéa; Hinrichs, Jörg; Stubenrauch, Cosima; Weiss, Jochen

    2014-06-01

    Surface properties, miscibility and self-assembly of mixtures of a food-grade αs-casein and the triblock copolymer PE6400 (PEO13-PPO30-PEO13) were examined. The properties at the surface were determined by surface pressure measurements for a 1:1 molar mixture. Comparison of the measured with the calculated isotherms show attractive interactions at surface pressures above 9mN/m. The miscibility gaps of solutions containing 0.004-0.2mmol/l αs-casein and 0.02-0.1mol/l polymer were examined. It was found that a one-phase region exists at distinct mixing ratios and temperatures. Comparison of the cloud points of mixtures of αs-casein and PE6400 with pure αs-casein showed that the presence of the triblock copolymer enhanced the solubility of the protein. The ζ-potential of the αs-casein solution decreased by addition of PE6400 to zero. Our results thus suggest that αs-casein and PE6400 are miscible. The results of the cloud point and ζ-potential measurements were explained by formation of a mixed aggregate where the PPO chains are anchored inside the hydrophobic part of the αs-casein while the PEO chains cover the charged hydrophilic part of the αs-casein thereby leading to an increase of the cloud point and a decrease in ζ-potential. This is in agreement with the attractive interactions between αs-casein and PE6400 as observed via surface pressure measurements at the surface.

  8. Understanding Flood Hazards and Vulnerabilities: New Approaches To Comprehensive Flood Risk Assessment In The U.k.

    NASA Astrophysics Data System (ADS)

    Kelman, I.; Spence, R.

    Flood risk assessment in the U.K. has traditionally considered the hazard to be princi- pally flood depth and the vulnerability to be principally damage resulting from water contact with property for a specified but arbitrary duration. Some efforts have factored in velocity and salinity at a superficial level while other research has recently exam- ined the danger of flood hazard parameters to human life. This work is valuable, but it has tended to ignore both the physical and conceptual processes which lead from flood hazards such as rainfall and sewage to a flood disaster with consequences such as property damage, casualties, and societal disruption. The work presented here uses a detailed analysis to propose a framework describing which flood vulnerabilities are susceptible to which flood hazards and how this fundamental knowledge translates into an understanding of the creation of flood risks. A flood damage scale is produced and a conceptual map of flood risk is drawn through categorising flood hazards and vulnerabilities and exploring their interaction. The physical description of flood haz- ard parameters and the parametersS potential effects form the basis for communication strategies focused on risk and vulnerability reduction.

  9. Enhanced sampling simulation analysis of the structure of lignin in the THF-water miscibility gap.

    PubMed

    Smith, Micholas Dean; Petridis, Loukas; Cheng, Xiaolin; Mostofian, Barmak; Smith, Jeremy C

    2016-03-07

    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. The present study thus suggests that THF-water based pretreatments may efficiently remove lignin from biomass even at relatively low (non-water boiling) temperatures.

  10. 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.

  11. CO2 miscible displacement enhanced oil recovery in Dutch North Sea

    SciTech Connect

    Alkemade, P.J.C.

    1995-12-31

    In the Dutch sector of the North Sea several relatively small oil deposits are present. Their locations are spread and only few oil fields are being produced. An attempt is made to investigate the feasibility of EOR application i.e. CO2 miscible displacement by a commonly available pressurized CO2 supply system. This feasibility study is based on an utilizes as much as possible past and present data bout existing oil fields, CO2 availability, compression and distribution pipelines to be installed and injection methods at existing production facilities.

  12. Flooding: A unique year

    USGS Publications Warehouse

    Putnam, A.L.

    1984-01-01

    Floods have been and continue to be one of the most destructive hazards facing the people of the United States. Of all the natural hazards, floods are the most widespread and the most ruinous to life and property. Today, floods are a greater menace to our welfare than ever before because we live in large numbers near water and have developed a complex reliance upon it. From large rivers to country creeks, from mountain rills to the trickles that occasionally dampen otherwise arid wastelands, every stream in the United States is subject to flooding at some time. Floods strike in myriad forms, including sea surges driven by wild winds or tsunamis churned into fury by seismic activity. By far the most frequent, however, standing in a class by themselves, are the inland, freshwater floods that are caused by rain, by melting snow and ice, or by the bursting of structures that man has erected to protect himself and his belongings from angry waters.

  13. Paleohydraulics and hydrodynamics of Scabland floods

    NASA Technical Reports Server (NTRS)

    Baker, V. R.

    1978-01-01

    The last major episode of scabland flooding (approx. 18,000-13,000 years B.P.) left considerable high-water mark evidence in the form of: (1) eroded channel margins; (2) depositional features; (3) ice-rafter erratics; and (4) divide crossings. These were used to reconstruct maximum flood stages and water-surface gradients. Engineering hydraulic calculation procedures allowed the analyses of flood discharges and mean velocities from these data. Secondary flow phenomena, including various forms of vortices and flow separations, are considered to have been the principal erosive processes. The intense pressure and velocity gradients of vortices along the irregular channel boundaries produced the plucking-type erosion.

  14. Flood regimes in a changing world: What do we know?

    NASA Astrophysics Data System (ADS)

    Bloeschl, G.

    2015-12-01

    There has been a surprisingly large number of major floods in the last years around the world which suggests that floods may have increased and will continue to increase in the next decades. However, the realism of such changes is still hotly discussed in the literature. In this presentation I will argue that a fresh look is needed at the flood change problem in terms of the causal factors including river training, land use changes and climate variability. Analysing spatial patterns of dynamic flood characteristics helps learn form the rich diversity of flood processes across the landscape. I will present a number of examples across Europe to illustrate the range of flood generation processes and the causal factors of changes in the flood regime. On the basis of these examples, I will demonstrate how comparative hydrology can assist in learning from the differences of flood characteristics between catchments both for present and future conditions. Focus on the interactions of the natural and human water system will be instrumental in making meaningful statements about future floods in a changing world. References Hall et al. (2014) Understanding Flood Regime Changes in Europe: A state of the art assessment. Hydrol. Earth Sys. Sc., 18, 2735-2772. Blöschl et al. (2015) Increasing river floods: fiction or reality? Wiley Interdisciplinary Reviews: Water. doi: 10.1002/wat2.1079

  15. The use of rheology to elucidate the granulation mechanisms of a miscible and immiscible system during continuous twin-screw melt granulation.

    PubMed

    Monteyne, Tinne; Heeze, Liza; Mortier, Séverine Thérèse F C; Oldörp, Klaus; Nopens, Ingmar; Remon, Jean-Paul; Vervaet, Chris; De Beer, Thomas

    2016-08-20

    Twin-screw hot melt granulation (TS HMG) is a valuable, but still unexplored alternative to granulate temperature and moisture sensitive drugs in a continuous way. Recently, the material behavior of an immiscible drug-binder blend during TS HMG was unraveled by using a rheometer and differential scanning calorimetry (DSC). Additionally, vibrational spectroscopic techniques proved the link between TS HMG and rheology since equal interactions at molecular level did occur in both processes. This allowed to use a rheometer to gain knowledge of the material behavior during hot melt processing of an immiscible drug-binder blend. However, miscibility of a drug-binder formulation and drug-binder interactions appear to influence the rheological properties and, hence conceivably also the granulation mechanism. The aim of this research was to examine if the TS HMG process of a miscible formulation system is comparable with the mechanism of an immiscible system and to evaluate whether rheology still serves as a useful tool to understand and optimize the hot melt granulation (HMG) process. The executed research (thermal analysis, rheological parameters and spectroscopic data) demonstrated the occurrence of a high and broad tan(δ) curve without a loss peak during the rheological temperature ramp which implies a higher material deformability without movement of the softened single polymer chains. Spectroscopic analysis revealed drug-polymer interactions which constrain the polymer to flow independently. As a result, the binder distribution step, which generally follows the immersion step, was hindered. This insight assisted the understanding of the granule properties. Inhomogeneous granules were produced due to large initial nuclei or adhesion of multiple smaller nuclei. Consequently, a higher granulation temperature was required in order to get the binder more homogeneously distributed within the granules.

  16. RASOR flood modelling

    NASA Astrophysics Data System (ADS)

    Beckers, Joost; Buckman, Lora; Bachmann, Daniel; Visser, Martijn; Tollenaar, Daniel; Vatvani, Deepak; Kramer, Nienke; Goorden, Neeltje

    2015-04-01

    Decision making in disaster management requires fast access to reliable and relevant information. We believe that online information and services will become increasingly important in disaster management. Within the EU FP7 project RASOR (Rapid Risk Assessment and Spatialisation of Risk) an online platform is being developed for rapid multi-hazard risk analyses to support disaster management anywhere in the world. The platform will provide access to a plethora of GIS data that are relevant to risk assessment. It will also enable the user to run numerical flood models to simulate historical and newly defined flooding scenarios. The results of these models are maps of flood extent, flood depths and flow velocities. The RASOR platform will enable to overlay historical event flood maps with observations and Earth Observation (EO) imagery to fill in gaps and assess the accuracy of the flood models. New flooding scenarios can be defined by the user and simulated to investigate the potential impact of future floods. A series of flood models have been developed within RASOR for selected case study areas around the globe that are subject to very different flood hazards: • The city of Bandung in Indonesia, which is prone to fluvial flooding induced by heavy rainfall. The flood hazard is exacerbated by land subsidence. • The port of Cilacap on the south coast of Java, subject to tsunami hazard from submarine earthquakes in the Sunda trench. • The area south of city of Rotterdam in the Netherlands, prone to coastal and/or riverine flooding. • The island of Santorini in Greece, which is subject to tsunamis induced by landslides. Flood models have been developed for each of these case studies using mostly EO data, augmented by local data where necessary. Particular use was made of the new TanDEM-X (TerraSAR-X add-on for Digital Elevation Measurement) product from the German Aerospace centre (DLR) and EADS Astrium. The presentation will describe the flood models and the

  17. Stochastic trigger model for flood peaks: 2. Application of the model to the flood peaks of Goksu-Karahacili

    NASA Astrophysics Data System (ADS)

    Kavvas, M. L.

    1982-04-01

    In order to assess the suitability of the stochastic trigger process in modeling flood peak occurrences in the time-discharge plane, the trigger process is applied to the flood peaks data of the Karahacili gaging station on the Goksu River, Turkey, in each of the flood seasons which are defined in the paper. The flood peak process in each flood season is treated as a transient stochastic process which starts at the beginning of the season and ends at the end of the season. Consequently, time-discharge nonhomogeneous trigger processes are used to model these seasonal flood peak processes. In each flood season the two-dimensional nonhomogeneous stochastic trigger (TDNST) model is calibrated by fitting its first theoretical time-discharge moment and its second theoretical time moment to the corresponding estimated moments of the observed flood peak counts at Goksu-Karahacili. Then in each flood season the theoretical two-dimensional probability mass function (pmf) of the variable discharge exceedence level (DEL) is calculated from the calibrated TDNST model for that flood season. The goodness of fit of the theoretical two-dimensional pmf to the empirical two-dimensional pmf of the Goksu-Karahacili flood peak counts in each flood season is tested by the chi-square goodness-of-fit (CSGQF) test. In all of the flood seasons the TDNST model passes the CSGOF test at discharge levels above the 500-m3/s DEL. This DEL corresponds to a river stage that is 1 m above the river bank stage at Goksu-Karahacili.

  18. SERVIR-Africa: Developing an Integrated Platform for Floods Disaster Management in Africa

    NASA Technical Reports Server (NTRS)

    Macharia, Daniel; Korme, Tesfaye; Policelli, Fritz; Irwin, Dan; Adler, Bob; Hong, Yang

    2010-01-01

    SERVIR-Africa is an ambitious regional visualization and monitoring system that integrates remotely sensed data with predictive models and field-based data to monitor ecological processes and respond to natural disasters. It aims addressing societal benefits including floods and turning data into actionable information for decision-makers. Floods are exogenous disasters that affect many parts of Africa, probably second only to drought in terms of social-economic losses. This paper looks at SERVIR-Africa's approach to floods disaster management through establishment of an integrated platform, floods prediction models, post-event flood mapping and monitoring as well as flood maps dissemination in support of flood disaster management.

  19. Investigating the Correlation between Miscibility and Physical Stability of Amorphous Solid Dispersions Using Fluorescence-Based Techniques.

    PubMed

    Tian, Bin; Tang, Xing; Taylor, Lynne S

    2016-11-07

    The purpose of this study was to investigate the feasibility of using a fluorescence-based technique to evaluate drug-polymer miscibility and to probe the correlation between miscibility and physical stability of amorphous solid dispersions (ASDs). Indomethacin-hydroxypropyl methylcellulose (IDM-HPMC), indomethacin-hydroxypropyl methylcellulose acetate succinate, and indomethacin-polyvinylpyrrolidone (IDM-PVP) were used as model systems. The miscibility of the IDM-polymer systems was evaluated by fluorescence spectroscopy, fluorescence imaging, differential scanning calorimetry (DSC), and infrared (IR) spectroscopy. The physical stability of IDM-polymer ASDs stored at 40 °C was evaluated using fluorescence imaging and X-ray diffraction (XRD). The experimentally determined miscibility limit of IDM with the polymers was 50-60%, 20-30%, and 70-80% drug loading for HPMC, HPMCAS, and PVP, respectively. The X-ray results showed that for IDM-HPMC ASDs, samples with a drug loading of less than 50% were maintained in amorphous form during the study period, while samples with drug loadings higher than 50% crystallized within 15 days. For IDM-HPMCAS ASDs, samples with drug loading less than 30% remained amorphous, while samples with drug loadings higher than 30% crystallized within 10 days. IDM-PVP ASDs were found to be resistant to crystallization for all compositions. Thus, a good correlation was observed between phase separation and reduced physical stability, suggesting that miscibility is indeed an important ASDs characteristic. In addition, fluorescence-based techniques show promise in the evaluation of drug-polymer miscibility.

  20. Climate change impacts on future flooding in Bangladesh

    NASA Astrophysics Data System (ADS)

    Mirza, M.

    2003-04-01

    Bangladesh is located at the tail end of the three large river systems- the Ganges, Brahmaputra and Meghna. About 92.5% of the basin area is located outside of its boundary. The country is frequently devastated by floods and can engulf up to 70% of the country. Economic damage could be as high as 10% of the GDP. Cross border and local precipitation plays a major role in generating floods in Bangladesh. However, precipitation over some cross border areas is really crucial for the flooding process. Any change in precipitation regime in those areas in future may aggravate flooding in Bangladesh. In this paper future flooding situation in Bangladesh has been assessed in a three-step procedure. First, stepwise regression method was applied to identify climatologically important regions those contribute to flooding. Second, precipitation scenarios were constructed. Third, the scenarios were applied in the regression models to determine future flood discharges in the Ganges, Brahmaputra and Meghna rivers in Bangladesh.

  1. Communicating Flood Risk with Street-Level Data

    NASA Astrophysics Data System (ADS)

    Sanders, B. F.; Matthew, R.; Houston, D.; Cheung, W. H.; Karlin, B.; Schubert, J.; Gallien, T.; Luke, A.; Contreras, S.; Goodrich, K.; Feldman, D.; Basolo, V.; Serrano, K.; Reyes, A.

    2015-12-01

    Coastal communities around the world face significant and growing flood risks that require an accelerating adaptation response, and fine-resolution urban flood models could serve a pivotal role in enabling communities to meet this need. Such models depict impacts at the level of individual buildings and land parcels or "street level" - the same spatial scale at which individuals are best able to process flood risk information - constituting a powerful tool to help communities build better understandings of flood vulnerabilities and identify cost-effective interventions. To measure understanding of flood risk within a community and the potential impact of street-level models, we carried out a household survey of flood risk awareness in Newport Beach, California, a highly urbanized coastal lowland that presently experiences nuisance flooding from high tides, waves and rainfall and is expected to experience a significant increase in flood frequency and intensity with climate change. Interviews were completed with the aid of a wireless-enabled tablet device that respondents could use to identify areas they understood to be at risk of flooding and to view either a Federal Emergency Management Agency (FEMA) flood map or a more detailed map prepared with a hydrodynamic urban coastal flood model (UCI map) built with grid cells as fine as 3 m resolution and validated with historical flood data. Results indicate differences in the effectiveness of the UCI and FEMA maps at communicating the spatial distribution of flood risk, gender differences in how the maps affect flood understanding, and spatial biases in the perception of flood vulnerabilities.

  2. Increasing river floods: fiction or reality?

    PubMed

    Blöschl, Günter; Gaál, Ladislav; Hall, Julia; Kiss, Andrea; Komma, Jürgen; Nester, Thomas; Parajka, Juraj; Perdigão, Rui A P; Plavcová, Lenka; Rogger, Magdalena; Salinas, José Luis; Viglione, Alberto

    2015-01-01

    There has been a surprisingly large number of major floods in the last years around the world, which suggests that floods may have increased and will continue to increase in the next decades. However, the realism of such changes is still hotly discussed in the literature. This overview article examines whether floods have changed in the past and explores the driving processes of such changes in the atmosphere, the catchments and the river system based on examples from Europe. Methods are reviewed for assessing whether floods may increase in the future. Accounting for feedbacks within the human-water system is important when assessing flood changes over lead times of decades or centuries. It is argued that an integrated flood risk management approach is needed for dealing with future flood risk with a focus on reducing the vulnerability of the societal system. WIREs Water 2015, 2:329-344. doi: 10.1002/wat2.1079 For further resources related to this article, please visit the WIREs website.

  3. Microwave remote sensing of flood inundation

    NASA Astrophysics Data System (ADS)

    Schumann, Guy J.-P.; Moller, Delwyn K.

    Flooding is one of the most costly natural disasters and thus mapping, modeling and forecasting flood events at various temporal and spatial scales is important for any flood risk mitigation plan, disaster relief services and the global (re-)insurance markets. Both computer models and observations (ground-based, airborne and Earth-orbiting) of flood processes and variables are of great value but the amount and quality of information available varies greatly with location, spatial scales and time. It is very well known that remote sensing of flooding, especially in the microwave region of the electromagnetic spectrum, can complement ground-based observations and be integrated with flood models to augment the amount of information available to end-users, decision-makers and scientists. This paper aims to provide a concise review of both the science and applications of microwave remote sensing of flood inundation, focusing mainly on synthetic aperture radar (SAR), in a variety of natural and man-made environments. Strengths and limitations are discussed and the paper will conclude with a brief account on perspectives and emerging technologies.

  4. Evaluation of various modelling approaches in flood routing simulation and flood area mapping

    NASA Astrophysics Data System (ADS)

    Papaioannou, George; Loukas, Athanasios; Vasiliades, Lampros; Aronica, Giuseppe

    2016-04-01

    An essential process of flood hazard analysis and mapping is the floodplain modelling. The selection of the modelling approach, especially, in complex riverine topographies such as urban and suburban areas, and ungauged watersheds may affect the accuracy of the outcomes in terms of flood depths and flood inundation area. In this study, a sensitivity analysis implemented using several hydraulic-hydrodynamic modelling approaches (1D, 2D, 1D/2D) and the effect of modelling approach on flood modelling and flood mapping was investigated. The digital terrain model (DTMs) used in this study was generated from Terrestrial Laser Scanning (TLS) point cloud data. The modelling approaches included 1-dimensional hydraulic-hydrodynamic models (1D), 2-dimensional hydraulic-hydrodynamic models (2D) and the coupled 1D/2D. The 1D hydraulic-hydrodynamic models used were: HECRAS, MIKE11, LISFLOOD, XPSTORM. The 2D hydraulic-hydrodynamic models used were: MIKE21, MIKE21FM, HECRAS (2D), XPSTORM, LISFLOOD and FLO2d. The coupled 1D/2D models employed were: HECRAS(1D/2D), MIKE11/MIKE21(MIKE FLOOD platform), MIKE11/MIKE21 FM(MIKE FLOOD platform), XPSTORM(1D/2D). The validation process of flood extent achieved with the use of 2x2 contingency tables between simulated and observed flooded area for an extreme historical flash flood event. The skill score Critical Success Index was used in the validation process. The modelling approaches have also been evaluated for simulation time and requested computing power. The methodology has been implemented in a suburban ungauged watershed of Xerias river at Volos-Greece. The results of the analysis indicate the necessity of sensitivity analysis application with the use of different hydraulic-hydrodynamic modelling approaches especially for areas with complex terrain.

  5. Preparation of carbamazepine-Soluplus solid dispersions by hot-melt extrusion, and prediction of drug-polymer miscibility by thermodynamic model fitting.

    PubMed

    Djuris, Jelena; Nikolakakis, Ioannis; Ibric, Svetlana; Djuric, Zorica; Kachrimanis, Kyriakos

    2013-05-01

    Hot-melt extrusion (HME) is a dust- and solvent-free continuous process enabling the preparation of a variety of solid dosage forms containing solid dispersions of poorly soluble drugs into thermoplastic polymers. Miscibility of drug and polymer is a prerequisite for stable solid dispersion formation. The present study investigates the feasibility of forming solid dispersions of carbamazepine (CBZ) into polyethyleneglycol-polyvinyl caprolactam-polyvinyl acetate grafted copolymer (Soluplus) by hot-melt extrusion. Physicochemical properties of the raw materials, extrudates, co-melted products, and corresponding physical mixtures were characterized by thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), attenuated total reflectance infrared (ATR-FTIR) spectroscopy and hot stage microscopy (HSM), while miscibility of CBZ and Soluplus was estimated on the basis of the Flory-Huggins theory, Hansen solubility parameters, and solid-liquid equilibrium equation. It was found that hot-melt extrusion of carbamazepine and Soluplus is feasible on a single-screw hot-melt extruder without the addition of plasticizers. DSC analysis and FTIR spectroscopy revealed that a molecular dispersion is formed when the content of CBZ does not exceed ∼5% w/w while higher CBZ content results in a microcrystalline dispersion of CBZ form III crystals, with the molecularly dispersed percentage increasing with extrusion temperature, at the risk of inducing transformation to the undesirable form I of CBZ. Thermodynamic modeling elucidated potential limitations and temperature dependence of solubility/dispersibility of carbamazepine in Soluplus hot-melt extrudates. The results obtained by thermodynamic models are in agreement with the findings of the HME processing, encouraging therefore their further application in the HME process development.

  6. Flood management: prediction of microbial contamination in large-scale floods in urban environments.

    PubMed

    Taylor, Jonathon; Lai, Ka Man; Davies, Mike; Clifton, David; Ridley, Ian; Biddulph, Phillip

    2011-07-01

    With a changing climate and increased urbanisation, the occurrence and the impact of flooding is expected to increase significantly. Floods can bring pathogens into homes and cause lingering damp and microbial growth in buildings, with the level of growth and persistence dependent on the volume and chemical and biological content of the flood water, the properties of the contaminating microbes, and the surrounding environmental conditions, including the restoration time and methods, the heat and moisture transport properties of the envelope design, and the ability of the construction material to sustain the microbial growth. The public health risk will depend on the interaction of these complex processes and the vulnerability and susceptibility of occupants in the affected areas. After the 2007 floods in the UK, the Pitt review noted that there is lack of relevant scientific evidence and consistency with regard to the management and treatment of flooded homes, which not only put the local population at risk but also caused unnecessary delays in the restoration effort. Understanding the drying behaviour of flooded buildings in the UK building stock under different scenarios, and the ability of microbial contaminants to grow, persist, and produce toxins within these buildings can help inform recovery efforts. To contribute to future flood management, this paper proposes the use of building simulations and biological models to predict the risk of microbial contamination in typical UK buildings. We review the state of the art with regard to biological contamination following flooding, relevant building simulation, simulation-linked microbial modelling, and current practical considerations in flood remediation. Using the city of London as an example, a methodology is proposed that uses GIS as a platform to integrate drying models and microbial risk models with the local building stock and flood models. The integrated tool will help local governments, health authorities

  7. Oil-Miscible and Non-Corrosive Phosphonium Ionic Liquids as Candidate Lubricant Additives

    SciTech Connect

    Yu, Bo; Bansal, Dinesh G; Qu, Jun; Sun, Xiaoqi; Luo, Huimin; Dai, Sheng; Blau, Peter Julian; Bunting, Bruce G; Mordukhovich, Gregory; Smolenski, Donald

    2012-01-01

    Ionic liquids (ILs) have been receiving considerable attention from the lubricants industry as potential friction and wear-reducing additives, but their solubility in oils is an issue. Unlike most ionic liquids that are insoluble in non-polar hydrocarbon oils, this study reports phosphonium-based ILs (PP-ILs) that are fully miscible with both mineral oil-based and synthetic lubricants. Both the cation and anion in quaternary structures, long alkyl chains, and capability of pairing the cation and the anion via a H-O bond are hypothesized to improve the compatibility between ions and neutral oil molecules. The measured viscosities of the oil-IL blends agree well with the Refutas equation that is for solutions containing multiple components. High thermal stability and non-corrosiveness were observed for the PP-ILs. Effective friction reduction and anti-wear functionality have been demonstrated in tribological tests when adding 5 wt% of a PP-IL into a base oil, suggesting potential applications for using the oil-miscible PP-ILs as lubricant additives.

  8. Quantum Turbulence Arising from Countersuperflow Instability in Miscible Two-component Bose-Einstein Condensates

    NASA Astrophysics Data System (ADS)

    Takeuchi, Hiromitsu; Ishino, Shungo; Tsubota, Makoto

    2014-05-01

    Turbulence is one of the great unsolved problems in physics. Quantum turbulence (QT) in superfluids is expected to give a prototype of turbulence much simpler than usual classical turbulence and has recently become one of the most important fields in low-temperature physics. Recent development of experimental technique enable us to study QT in atomic Bose-Einstein condensates (BECs). Recently, we proposed that countersuperflow, a flow state of miscible superfluids with a relative velocity, can lead to turbulence after the characteristic instability development of vortex nucleation and vortex reconnection in miscible two-component BECs. QT of two-component BECs can provide another prototype of turbulence because eddies in classical turbulence may be mimicked by vorticity distribution without singularity in this system. In this presentation, we will report on our numerical analysis of the parameter dependence of the statistical property, such as energy spectrum and enstrophy distribution, of the QT arising from countersuperflow instability (CSI) in two-component condensates. This work was supported by JSPS KAKENHI Grant Numbers 25887042, 26870500 and the MEXT KAKENHI (No. 22103003).

  9. Flow and Reactive Transport of Miscible and Immiscible Solutions in Fractured & Porous Media

    NASA Astrophysics Data System (ADS)

    Ryerson, F. J.; Ezzedine, S. M.; Antoun, T.

    2012-12-01

    Miscible and immiscible flows are important phenomena encountered in many industrial and engineering applications such as hydrothermal systems, oil and gas reservoirs, salt/water intrusion, geological carbon sequestration etc… Under the influence of gravity, the flow of fluids with sufficiently large density ratios may become unstable leading to instabilities, mixing and in some instances reactions at the interfacial contact between fluids. Flow is governed by a combination of momentum and mass conservation equations that describe the flow of the fluid phase and a convection-diffusion equation describing the change of concentration in the fluid phase. When hydrodynamic instabilities develop it may be difficult to use standard grid-based methods to model miscible/immiscible flow because the domains occupied by fluids evolve constantly with time. In the current study, adaptive mesh refinement finite elements method has been used to solve for flow and transport equations. Furthermore, a particle tracking scheme has also been implemented to track the kinematics of swarm of particles injected into the porous fractured media to quantify surface area, sweeping zones, and their impact on porosity changes. Spatial and temporal moments of the fingering instabilities and the development of reaction zones and the impact of kinetic reaction at the fluid/solution interfaces have also been analyzed. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  10. 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.

  11. Low temperature synthesis of Ru–Cu alloy nanoparticles with the compositions in the miscibility gap

    SciTech Connect

    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(NH{sub 3}){sub 5}Cl][Cu(C{sub 2}O{sub 4}){sub 2}H{sub 2}O]—the precursor of nanoalloys combining ruthenium and copper was prepared. It crystallizes in the monoclinic space group P2{sub 1}/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 Cu{sub x}Ru{sub 1−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. - Highlights: • We synthesized new precursor of CuRu metastable nanoalloys. • Thermal properties of the prepared salt were examined in different atmospheres. • Thermodestruction mechanism of precursor are studied. • Cu{sub 0.12}Ru{sub 0.88} nanoalloy with the compositions in the miscibility gap is obtained. • Catalytic conversion of CO on copper–ruthenium oxide composite were examined.

  12. 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

  13. Cellulose acetate butyrate/poly(caprolactonetriol) blends: Miscibility, mechanical properties, and in vivo inflammatory response.

    PubMed

    Kanis, Luiz A; Marques, Ellen L; Zepon, Karine M; Pereira, Jefferson R; Pamato, Saulo; de Oliveira, Marcelo T; Danielski, Lucinéia G; Petronilho, Fabricia C

    2014-11-01

    This study reports the results of the characterization of cellulose acetate butyrate and polycaprolactone-triol blends in terms of miscibility, swelling capacity, mechanical properties, and inflammatory response in vivo. The cellulose acetate butyrate film was opaque and rigid, with glass transition (T g ) at 134℃ and melting temperature of 156℃. The cellulose acetate butyrate/polycaprolactone-triol films were transparent up to a polycaprolactone-triol content of 60%. T g of the cellulose acetate butyrate films decreased monotonically as polycaprolactone-triol was added to the blend, thus indicating miscibility. FTIR spectroscopy revealed a decrease in intramolecular hydrogen bonding in polycaprolactone-triol, whereas no hydrogen bonding was observed between cellulose acetate butyrate and -OH from polycaprolactone-triol. The increase in polycaprolactone-triol content in the blend decreased the water uptake. An increase in polycaprolactone-triol content decreased the modulus of elasticity and increased the elongation at break. A cellulose acetate butyrate/polycaprolactone-triol 70/30 blend implanted in rats showed only an acute inflammatory response 7 days after surgery. No change in inflammation mediators was observed.

  14. 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.

  15. Experimental study of 3D Rayleigh-Taylor convection between miscible fluids in a porous medium

    NASA Astrophysics Data System (ADS)

    Nakanishi, Yuji; Hyodo, Akimitsu; Wang, Lei; Suekane, Tetsuya

    2016-11-01

    The natural convection of miscible fluids in porous media has applications in several fields, such as geoscience and geoengineering, and can be employed for the geological storage of CO2. In this study, we used 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 appeared at the interface. As the wavelength and amplitude increased, descending fingers formed on the interface and extended vertically downward; in addition, ascending and highly symmetric fingers formed. The adjacent fingers were cylindrical in shape and coalesced to form large fingers. The fingers appearing on the interface tended to become finer with increasing Rayleigh number, which is consistent with linear perturbation theory. When the Péclet number exceeded 10, transverse dispersion increased the finger diameter and enhanced the finger coalescence, strongly impacting the decrease in finger number density. When mechanical dispersion was negligible, the finger-extension velocity and the dimensionless mass-transfer rate scaled with the characteristic velocity and the Rayleigh number with an appropriate length scale. Mechanical dispersion not only reduced the onset time but also enhanced the mass transport.

  16. ON EFFECT OF HAZARD MAP ON CONS CIOUSNESS OF FLOOD DISASTER PREVENSION OF RESIDENTS WHO EXPERIENCED FLOOD RECENTLY

    NASA Astrophysics Data System (ADS)

    Asai, Koji; Koga, Syota; Sakakibara, Hiroyuki

    In this paper, the effect of the flood hazard map distributed to the residents who experienced flood disasters recently and an effective method for improving consciousness of flood di saster prevention are discussed. The questionnaire surveys were conducted on the residents living in the middle basin of the Nishiki River, Iwakuni city, Yamaguchi Prefecture, before and after the distribution of the hazard map. It is found from this investigation that "knowledge", "att achment", and "crisis", are the main factors in the psychological process related to the flood prevention behavior. The effect of the distribution of the hazard map is judged from the probability of the flood prevention behavior. In addition, it is also found that "knowledge", "flood experiment of T0514", "crisis", "eff ectiveness", "load", and "easy reading of the hazard map", are keys to improve the cons ciousness of flood di saster prevention.

  17. High resolution mapping of flood hazard for South Korea

    NASA Astrophysics Data System (ADS)

    Ghosh, Sourima; Nzerem, Kechi; Zovi, Francesco; Li, Shuangcai; Mei, Yi; Assteerawatt, Anongnart; Hilberts, Arno; Tillmanns, Stephan; Mitas, Christos

    2015-04-01

    Floods are one of primary natural hazards that affect South Korea. During the past 15 years, catastrophic flood events which mainly have occurred during the rainy and typhoon seasons - especially under condition where soils are already saturated, have triggered substantial property damage with an average annual loss of around US1.2 billion (determined from WAter Management Information System's flood damage database for years 2002-2011) in South Korea. According to Seoul Metropolitan Government, over 16,000 households in the capital city Seoul were inundated during 2010 flood events. More than 10,000 households in Seoul were apparently flooded during one major flood event due to torrential rain in July 2011. Recently in August 2014, a serious flood event due to heavy rainfall hit the Busan region in the south east of South Korea. Addressing the growing needs, RMS has recently released country-wide high resolution combined flood return period maps for post-drainage local "pluvial" inundation and undefended large-scale "fluvial" inundation to aid the government and the insurance industry in the evaluation of comprehensive flood risk. RMS has developed a flood hazard model for South Korea to generate inundation depths and extents for a range of flood return periods. The model is initiated with 30 years of historical meteorological forcing data and calibrated to daily observations at over 100 river gauges across the country. Simulations of hydrologic processes are subsequently performed based on a 2000 year set of stochastic forcing. Floodplain inundation processes are modelled by numerically solving the shallow water equations using finite volume method on GPUs. Taking into account the existing stormwater drainage standards, economic exposure densities, etc., reasonable flood maps are created from inundation model output. Final hazard maps at one arcsec grid resolution can be the basis for both evaluating and managing flood risk, its economic impacts, and insured flood

  18. Necessity of Flood Early Warning Systems in India

    NASA Astrophysics Data System (ADS)

    Kurian, C.; Natesan, U.; Durga Rao, K. H. V.

    2014-12-01

    India is one of the highly flood prone countries in the world. National flood commission has reported that 400,000 km² of geographical area is prone to floods, constituting to twelve percent of the country's geographical area. Despite the reoccurrences of floods, India still does not have a proper flood warning system. Probably this can be attributed to the lack of trained personnel in using advanced techniques. Frequent flood hazards results in damage to livelihood, infrastructure and public utilities. India has a potential to develop an early warning system since it is one of the few countries where satellite based inputs are regularly used for monitoring and mitigating floods. However, modeling of flood extent is difficult due to the complexity of hydraulic and hydrologic processes during flood events. It has been reported that numerical methods of simulations can be effectively used to simulate the processes correctly. Progress in computational resources, data collection and development of several numerical codes has enhanced the use of hydrodynamic modeling approaches to simulate the flood extent in the floodplains. In this study an attempt is made to simulate the flood in one of the sub basins of Godavari River in India using hydrodynamic modeling techniques. The modeling environment includes MIKE software, which simulates the water depth at every grid cell of the study area. The runoff contribution from the catchment was calculated using Nebdor Afstromnings model. With the hydrodynamic modeling approach, accuracy in discharge and water level computations are improved compared to the conventional methods. The results of the study are proming to develop effective flood management plans in the basin. Similar studies could be taken up in other flood prone areas of the country for continuous modernisation of flood forecasting techniques, early warning systems and strengthening decision support systems, which will help the policy makers in developing management

  19. Validation of a Global Hydrodynamic Flood Inundation Model

    NASA Astrophysics Data System (ADS)

    Bates, P. D.; Smith, A.; Sampson, C. C.; Alfieri, L.; Neal, J. C.

    2014-12-01

    In this work we present first validation results for a hyper-resolution global flood inundation model. We use a true hydrodynamic model (LISFLOOD-FP) to simulate flood inundation at 1km resolution globally and then use downscaling algorithms to determine flood extent and depth at 90m spatial resolution. Terrain data are taken from a custom version of the SRTM data set that has been processed specifically for hydrodynamic modelling. Return periods of flood flows along the entire global river network are determined using: (1) empirical relationships between catchment characteristics and index flood magnitude in different hydroclimatic zones derived from global runoff data; and (2) an index flood growth curve, also empirically derived. Bankful return period flow is then used to set channel width and depth, and flood defence impacts are modelled using empirical relationships between GDP, urbanization and defence standard of protection. The results of these simulations are global flood hazard maps for a number of different return period events from 1 in 5 to 1 in 1000 years. We compare these predictions to flood hazard maps developed by national government agencies in the UK and Germany using similar methods but employing detailed local data, and to observed flood extent at a number of sites including St. Louis, USA and Bangkok in Thailand. Results show that global flood hazard models can have considerable skill given careful treatment to overcome errors in the publicly available data that are used as their input.

  20. "Prophetic vision, vivid imagination": The 1927 Mississippi River flood

    NASA Astrophysics Data System (ADS)

    Smith, James A.; Baeck, Mary Lynn

    2015-12-01

    The 1927 flood in the Lower Mississippi River was the most destructive flood in American history, inundating more than 70,000 km2 of land, resulting in approximately 500 fatalities and leaving more than 700,000 people homeless. Despite the prominence of the 1927 flood, details on the flood, and the storms that produced the flood, are sparse. We examine the hydrometeorology and hydroclimatology of the 1927 flood in the Lower Mississippi River through downscaling simulations of the storms that were responsible for catastrophic flooding and through empirical analyses of rainfall and streamflow records. We use Twentieth Century Reanalysis fields as boundary conditions and initial conditions for downscaling simulations using the Weather Research and Forecasting (WRF) model. We place the hydrometeorological analyses of the 1927 storms in a hydroclimatological context through analyses of the Twentieth Century Reanalysis fields. Analyses are designed to assess the physical processes that control the upper tail of flooding in the Lower Mississippi River. We compare the 1927 flood in the Lower Mississippi River to floods in 1937 and 2011 that represent the most extreme flooding in the Lower Mississippi River.

  1. Glacier generated floods

    USGS Publications Warehouse

    Walder, J.S.; Fountain, A.G.; ,

    1997-01-01

    Destructive floods result from drainage of glacier-dammed lakes and sudden release of water stored within glaciers. There is a good basis - both empirical and theoretical - for predicting the magnitude of floods from ice-dammed lakes, although some aspects of flood initiation need to be better understood. In contrast, an understanding of floods resulting from release of internally stored water remains elusive, owing to lack of knowledge of how and where water is stored and to inadequate understanding of the complex physics of the temporally and spatially variable subglacial drainage system.Destructive floods result from drainage of glacier-dammed lakes and sudden release of water stored within glaciers. There is a good basis - both empirical and theoretical - for predicting the magnitude of floods from ice-dammed lakes, although some aspects of flood initiation need to be better understood. In contrast, an understanding of floods resulting from release of internally stored water remains elusive, owing to lack of knowledge of how and where water is stored and to inadequate understanding of the complex physics of the temporally and spatially variable subglacial drainage system.

  2. Discover Floods Educators Guide

    ERIC Educational Resources Information Center

    Project WET Foundation, 2009

    2009-01-01

    Now available as a Download! This valuable resource helps educators teach students about both the risks and benefits of flooding through a series of engaging, hands-on activities. Acknowledging the different roles that floods play in both natural and urban communities, the book helps young people gain a global understanding of this common--and…

  3. The Spokane flood controversy

    NASA Technical Reports Server (NTRS)

    Baker, V. R.

    1978-01-01

    An enormous plexus of proglacial channels that eroded into the loess and basalt of the Columbia Plateau, eastern Washington is studied. This channeled scabland contained erosional and depositional features that were unique among fluvial phenomena. Documentation of the field relationships of the region explains the landforms as the product of a relatively brief, but enormous flood, then so-called the Spokane flood.

  4. Flood hazard and flood risk assessment using a time series of satellite images: a case study in Namibia.

    PubMed

    Skakun, Sergii; Kussul, Nataliia; Shelestov, Andrii; Kussul, Olga

    2014-08-01

    In this article, the use of time series of satellite imagery to flood hazard mapping and flood risk assessment is presented. Flooded areas are extracted from satellite images for the flood-prone territory, and a maximum flood extent image for each flood event is produced. These maps are further fused to determine relative frequency of inundation (RFI). The study shows that RFI values and relative water depth exhibit the same probabilistic distribution, which is confirmed by Kolmogorov-Smirnov test. The produced RFI map can be used as a flood hazard map, especially in cases when flood modeling is complicated by lack of available data and high uncertainties. The derived RFI map is further used for flood risk assessment. Efficiency of the presented approach is demonstrated for the Katima Mulilo region (Namibia). A time series of Landsat-5/7 satellite images acquired from 1989 to 2012 is processed to derive RFI map using the presented approach. The following direct damage categories are considered in the study for flood risk assessment: dwelling units, roads, health facilities, and schools. The produced flood risk map shows that the risk is distributed uniformly all over the region. The cities and villages with the highest risk are identified. The proposed approach has minimum data requirements, and RFI maps can be generated rapidly to assist rescuers and decisionmakers in case of emergencies. On the other hand, limitations include: strong dependence on the available data sets, and limitations in simulations with extrapolated water depth values.

  5. 78 FR 5821 - Final Flood Hazard Determinations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-28

    ... SECURITY Federal Emergency Management Agency Final Flood Hazard Determinations AGENCY: Federal Emergency Management Agency, DHS. ACTION: Final Notice. SUMMARY: Flood hazard determinations, which may include additions or modifications of Base Flood Elevations (BFEs), base flood depths, Special Flood Hazard...

  6. 78 FR 21143 - Final Flood Hazard Determinations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-09

    ... SECURITY Federal Emergency Management Agency Final Flood Hazard Determinations AGENCY: Federal Emergency Management Agency, DHS. ACTION: Final notice. SUMMARY: Flood hazard determinations, which may include additions or modifications of Base Flood Elevations (BFEs), base flood depths, Special Flood Hazard...

  7. 78 FR 52953 - Final Flood Hazard Determinations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-27

    ... SECURITY Federal Emergency Management Agency Final Flood Hazard Determinations AGENCY: Federal Emergency Management Agency, DHS. ACTION: Final Notice. SUMMARY: Flood hazard determinations, which may include additions or modifications of Base Flood Elevations (BFEs), base flood depths, Special Flood Hazard...

  8. 78 FR 52954 - Final Flood Hazard Determinations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-27

    ... SECURITY Federal Emergency Management Agency Final Flood Hazard Determinations AGENCY: Federal Emergency Management Agency, DHS. ACTION: Final notice. SUMMARY: Flood hazard determinations, which may include additions or modifications of Base Flood Elevations (BFEs), base flood depths, Special Flood Hazard...

  9. 78 FR 5820 - Final Flood Hazard Determinations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-28

    ... SECURITY Federal Emergency Management Agency Final Flood Hazard Determinations AGENCY: Federal Emergency Management Agency, DHS. ACTION: Final Notice. SUMMARY: Flood hazard determinations, which may include additions or modifications of Base Flood Elevations (BFEs), base flood depths, Special Flood Hazard...

  10. A Methodology to Define Flood Resilience

    NASA Astrophysics Data System (ADS)

    Tourbier, J.

    2012-04-01

    Flood resilience has become an internationally used term with an ever-increasing number of entries on the Internet. The SMARTeST Project is looking at approaches to flood resilience through case studies at cities in various countries, including Washington D.C. in the United States. In light of U.S. experiences a methodology is being proposed by the author that is intended to meet ecologic, spatial, structural, social, disaster relief and flood risk aspects. It concludes that: "Flood resilience combines (1) spatial, (2) structural, (3) social, and (4) risk management levels of flood preparedness." Flood resilience should incorporate all four levels, but not necessarily with equal emphasis. Stakeholders can assign priorities within different flood resilience levels and the considerations they contain, dividing 100% emphasis into four levels. This evaluation would be applied to planned and completed projects, considering existing conditions, goals and concepts. We have long known that the "road to market" for the implementation of flood resilience is linked to capacity building of stakeholders. It is a multidisciplinary enterprise, involving the integration of all the above aspects into the decision-making process. Traditional flood management has largely been influenced by what in the UK has been called "Silo Thinking", involving constituent organizations that are responsible for different elements, and are interested only in their defined part of the system. This barrier to innovation also has been called the "entrapment effect". Flood resilience is being defined as (1) SPATIAL FLOOD RESILIENCE implying the management of land by floodplain zoning, urban greening and management to reduce storm runoff through depression storage and by practicing Sustainable Urban Drainage (SUD's), Best Management Practices (BMP's, or Low Impact Development (LID). Ecologic processes and cultural elements are included. (2) STRUCTURAL FLOOD RESILIENCE referring to permanent flood defense

  11. An automated approach to flood mapping

    NASA Astrophysics Data System (ADS)

    Sun, Weihua; Mckeown, Donald M.; Messinger, David W.

    2012-10-01

    Heavy rain from Tropical Storm Lee resulted in a major flood event for the southern tier of New York State in early September 2011 causing evacuation of approximately 20,000 people in and around the city of Binghamton. In support of the New York State Office of Emergency Management, a high resolution multispectral airborne sensor (WASP) developed by RIT was deployed over the flooded area to collect aerial images. One of the key benefits of these images is their provision for flood inundation area mapping. However, these images require a significant amount of storage space and the inundation mapping process is conventionally carried out using manual digitization. In this paper, we design an automated approach for flood inundation mapping from the WASP airborne images. This method employs Spectral Angle Mapper (SAM) for color RGB or multispectral aerial images to extract the flood binary map; then it uses a set of morphological processing and a boundary vectorization technique to convert the binary map into a shapefile. This technique is relatively fast and only requires the operator to select one pixel on the image. The generated shapefile is much smaller than the original image and can be imported to most GIS software packages. This enables critical flood information to be shared with and by disaster response managers very rapidly, even over cellular phone networks.

  12. Flood Warning and Forecasting System in Slovakia

    NASA Astrophysics Data System (ADS)

    Leskova, Danica

    2016-04-01

    In 2015, it finished project Flood Warning and Forecasting System (POVAPSYS) as part of the flood protection in Slovakia till 2010. The aim was to build POVAPSYS integrated computerized flood forecasting and warning system. It took a qualitatively higher level of output meteorological and hydrological services in case of floods affecting large territorial units, as well as local flood events. It is further unfolding demands on performance and coordination of meteorological and hydrological services, troubleshooting observation, evaluation of data, fast communication, modeling and forecasting of meteorological and hydrological processes. Integration of all information entering and exiting to and from the project POVAPSYS provides Hydrological Flood Forecasting System (HYPOS). The system provides information on the current hydrometeorological situation and its evolution with the generation of alerts and notifications in case of exceeding predefined thresholds. HYPOS's functioning of the system requires flawless operability in critical situations while minimizing the loss of its key parts. HYPOS is a core part of the project POVAPSYS, it is a comprehensive software solutions based on a modular principle, providing data and processed information including alarms, in real time. In order to achieve full functionality of the system, in proposal, we have put emphasis on reliability, robustness, availability and security.

  13. A global flash flood forecasting system

    NASA Astrophysics Data System (ADS)

    Baugh, Calum; Pappenberger, Florian; Wetterhall, Fredrik; Hewson, Tim; Zsoter, Ervin

    2016-04-01

    resolution appropriate to the NWP system. We then demonstrate how these warning areas could eventually complement existing global systems such as the Global Flood Awareness System (GloFAS), to give warnings of flash floods. This work demonstrates the possibility of creating a global flash flood forecasting system based on forecasts from existing global NWP systems. Future developments, in post-processing for example, will need to address an under-prediction bias, for extreme point rainfall, that is innate to current-generation global models.

  14. Iowa Flood Information System

    NASA Astrophysics Data System (ADS)

    Demir, I.; Krajewski, W. F.; Goska, R.; Mantilla, R.; Weber, L. J.; Young, N.

    2011-12-01

    The Iowa Flood Information System (IFIS) is a web-based platform developed by the Iowa Flood Center (IFC) to provide access to flood inundation maps, real-time flood conditions, flood forecasts both short-term and seasonal, flood-related data, information and interactive visualizations for communities in Iowa. The key element of the system's architecture is the notion of community. Locations of the communities, those near streams and rivers, define basin boundaries. The IFIS provides community-centric watershed and river characteristics, weather (rainfall) conditions, and streamflow data and visualization tools. Interactive interfaces allow access to inundation maps for different stage and return period values, and flooding scenarios with contributions from multiple rivers. Real-time and historical data of water levels, gauge heights, and rainfall conditions are available in the IFIS by streaming data from automated IFC bridge sensors, USGS stream gauges, NEXRAD radars, and NWS forecasts. Simple 2D and 3D interactive visualizations in the IFIS make the data more understandable to general public. Users are able to filter data sources for their communities and selected rivers. The data and information on IFIS is also accessible through web services and mobile applications. The IFIS is optimized for various browsers and screen sizes to provide access through multiple platforms including tablets and mobile devices. The IFIS includes a rainfall-runoff forecast model to provide a five-day flood risk estimate for around 500 communities in Iowa. Multiple view modes in the IFIS accommodate different user types from general public to researchers and decision makers by providing different level of tools and details. River view mode allows users to visualize data from multiple IFC bridge sensors and USGS stream gauges to follow flooding condition along a river. The IFIS will help communities make better-informed decisions on the occurrence of floods, and will alert communities

  15. May flood-poor periods be more dangerous than flood-rich periods?

    NASA Astrophysics Data System (ADS)

    Salinas, Jose Luis; Di Baldassarre, Giuliano; Viglione, Alberto; Kuil, Linda; Bloeschl, Guenter

    2014-05-01

    River floods are among the most devastating natural hazards experienced by populations that, since the earliest recorded civilisations, have settled in floodplains because they offer favourable conditions for trade, agriculture, and economic development. The occurrence of a flood may cause loss of lives and tremendous economic damages and, therefore, is rightly seen as a very negative event by the communities involved. Occurrence of many floods in a row is, of course, even more frustrating and is rightly considered a unbearable calamity. Unfortunately, the occurrence of many floods in a limited number of consecutive years is not unusual. In many places in the world, it has been observed that extreme floods do not arrive randomly but cluster in time into flood-poor and flood-rich periods consistent with the Hurst effect. If this is the case, when are the people more in danger? When should people be more scared? In flood-poor or flood-rich periods? In this work, a Socio-Hydrology model (Di Baldassarre et al., 2013; Viglione et al., 2014) is used to show that, maybe counter-intuitively, flood-poor periods may be more dangerous than flood-rich periods. The model is a conceptualisation of a hypothetical setting of a city at a river where a community evolves, making choices between flood management options on the floodplain. The most important feedbacks between the economic, political, technological and hydrological processes of the evolution of that community are represented in the model. In particular, the model also accounts in a dynamic way for the evolution of the the community awareness to flood risk. Occurrence of floods tends to increase peoples' recognition that their property is in an area that is potentially at risk of flooding, both at the scales of individuals and communities, which is one of the main reasons why flood coping actions are taken. It is shown through examples that frequent flood events may result in moderate damages because they ensure that the

  16. How do changes along the risk chain affect flood risk?

    NASA Astrophysics Data System (ADS)

    Merz, B.; Apel, H.; Guse, B.; Nguyen, V. D.; Falter, D.; Kreibich, H.; Schroeter, K.; Vorogushyn, S.

    2015-12-01

    Flood risk management is increasingly based on risk assessments whereas risk is defined as the probability of flood losses. The quantification of flood risk ideally considers the complete risk chain, from the atmospheric processes, through the catchment and river system processes to the damage mechanisms in the affected areas. For a given flood risk system, a multitude of changes can occur along this risk chain possibly affecting flood risk. Hence, it is important to understand how changes in different risk components affect the spatio-temporal distribution of risk. Applying a flood risk model chain to German case studies, we analyze how changes propagate along the risk chain. We discuss how they influence different parts of the risk curve, for example, whether a certain change has a similar influence on low probability/high impact events and high probability/low impact events. This is important information for risk-based design and risk management.

  17. Flood hazard assessment for french NPPs

    NASA Astrophysics Data System (ADS)

    Rebour, Vincent; Duluc, Claire-Marie; Guimier, Laurent

    2015-04-01

    This paper presents the approach for flood hazard assessment for NPP which is on-going in France in the framework of post-Fukushima activities. These activities were initially defined considering both European "stress tests" of NPPs pursuant to the request of the European Council, and the French safety audit of civilian nuclear facilities in the light of the Fukushima Daiichi accident. The main actors in that process are the utility (EDF is, up to date, the unique NPP's operator in France), the regulatory authority (ASN) and its technical support organization (IRSN). This paper was prepared by IRSN, considering official positions of the other main actors in the current review process, it was not officially endorsed by them. In France, flood hazard to be considered for design basis definition (for new NPPs and for existing NPPs in periodic safety reviews conducted every 10 years) was revised before Fukushima-Daichi accident, due to le Blayais NPP December 1999 experience (partial site flooding and loss of some safety classified systems). The paper presents in the first part an overview of the revised guidance for design basis flood. In order to address design extension conditions (conditions that could result from natural events exceeding the design basis events), a set of flooding scenarios have been defined by adding margins on the scenarios that are considered for the design. Due to the diversity of phenomena to be considered for flooding hazard, the margin assessment is specific to each flooding scenario in terms of parameter to be penalized and of degree of variation of this parameter. The general approach to address design extension conditions is presented in the second part of the paper. The next parts present the approach for five flooding scenarios including design basis scenario and additional margin to define design extension scenarios.

  18. 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.

  19. Understanding liquid mixture phase miscibility via pair energy parameter behaviors with respect to temperatures determined from molecular simulations.

    PubMed

    Oh, Suk Yung; Bae, Young Chan

    2011-05-19

    The miscibility behaviors of binary liquid mixtures were studied by a combination of molecular simulations and thermodynamic theories. Pairwise interaction parameters were obtained from molecular simulations that accounted for the effect of temperature. From a thermodynamic perspective, different types of liquid-liquid equilibrium (LLE) and different degrees of miscibility can be expressed in terms of energy behaviors with respect to temperature. Our simulation results proved this viewpoint by showing a correspondence between the simulation results and experimental observations. To describe phase diagrams, thermodynamic modeling is presented using the energy parameters obtained from the simulations. Correlations are needed to correct size mismatches between the simulations and the thermodynamic model. Using this method, not only the upper critical solution temperature (UCST) but also the closed-loop miscibility phase diagrams could be calculated without requiring additional parameters for specific interactions. The utility of this method is demonstrated for mixtures containing water, hydrocarbon, alcohols, aldehydes, ketones, chlorides, amines, nitriles, sulfides, and other organic liquids in various temperature ranges. The method presented in this paper can facilitate the understanding of the miscibilities in binary liquid mixtures from the viewpoint of thermal energy behaviors.

  20. Effect of flooding on C metabolism of flood-tolerant (Quercus robur) and non-tolerant (Fagus sylvatica) tree species.

    PubMed

    Ferner, Eleni; Rennenberg, Heinz; Kreuzwieser, Jürgen

    2012-02-01

    Flooding is assumed to cause an energy crisis in plants because-due to a lack of O(2)-mitochondrial respiration is replaced by alcoholic fermentation which yields considerably less energy equivalents. In the present study, the effect of flooding on the carbon metabolism of flooding-tolerant pedunculate oak (Quercus robur L.) and flooding-sensitive European beech (Fagus sylvatica L.) seedlings was characterized. Whereas soluble carbohydrate concentrations dropped in roots of F. sylvatica, they were constant in Q. robur during flooding. At the same time, root alcohol dehydrogenase activities were decreased in beech but not in oak, suggesting substrate limitation of alcoholic fermentation in beech roots. Surprisingly, leaf and phloem sap sugar concentrations increased in both species but to a much higher degree in beech. This finding suggests that the phloem unloading process in flooding-sensitive beech was strongly impaired. It is assumed that root-derived ethanol is transported to the leaves via the transpiration stream. This mechanism is considered an adaptation to flooding because it helps avoid the accumulation of toxic ethanol in the roots and supports the whole plant's carbon metabolism by channelling ethanol into the oxidative metabolism of the leaves. A labelling experiment demonstrated that in the leaves of flooded trees, ethanol metabolism does not differ between flooded beech and oak, indicating that processes in the roots are crucial for the trees' flooding tolerance.

  1. Large miscibility gap in the Ba(MnxFe1-x)2As2 system

    NASA Astrophysics Data System (ADS)

    Pandey, Abhishek; Anand, V. K.; Johnston, D. C.

    2011-07-01

    The compounds BaMn2As2 and BaFe2As2 both crystallize in the body-centered-tetragonal ThCr2Si2-type (122-type) structure at room temperature but exhibit quite different unit cell volumes and very different magnetic and electronic transport properties. Evidently reflecting these disparities, we have discovered a large miscibility gap in the system Ba(MnxFe1-x)2As2. Rietveld refinements of powder x-ray diffraction (XRD) measurements on samples slow-cooled from 1000 °C to room temperature (RT) reveal a two-phase mixture of BaMn2As2 and Ba(Mn0.12Fe0.88)2As2 phases together with impurity phases for x=0.2, 0.4, 0.5, 0.6, and 0.8. We infer that there exists a miscibility gap in this system at 300 K with composition limits 0.12≲x≲1. For samples quenched from 1000 °C to 77 K, the refinements of RT XRD data indicate that the miscibility gap at RT narrows at 1000 °C to 0.2≲x≲0.8. Samples with x=0.4, 0.5, and 0.6 quenched from 1100 to 1400 °C to 77 K contain a single 122-type phase together with significant amounts of Fe1-xMnxAs and FeAs2 impurity phases. These results indicate that the system is not a pseudobinary system over the whole composition range and that the 122-type phase has a significant homogeneity range at these temperatures. Magnetic susceptibility χ, electrical resistivity ρ, and heat capacity measurements versus temperature T of the single-phase quenched polycrystalline samples with x=0.2 and 0.8 are reported. We also report attempts to grow single crystals of the substituted compounds Ba(Mn1-xTx)2As2 (T = Cr, Fe, Co, Ni, Cu, Ru, Rh, Pd, Re, and Pt) and BaMn2(As1-xSbx)2 out of Sn flux. Energy-dispersive x-ray analyses show that most of these elements do not substitute into the lattice in amounts greater than 0.5%. However, concentrations of 4.4%, ~10% and 2.6% were achieved for Cr, Fe, and Sb substitutions, respectively, and χ(T) and ρ(T) data for these crystals are presented.

  2. Flood Insurance in Canada: Implications for Flood Management and Residential Vulnerability to Flood Hazards

    NASA Astrophysics Data System (ADS)

    Oulahen, Greg

    2015-03-01

    Insurance coverage of damage caused by overland flooding is currently not available to Canadian homeowners. As flood disaster losses and water damage claims both trend upward, insurers in Canada are considering offering residential flood coverage in order to properly underwrite the risk and extend their business. If private flood insurance is introduced in Canada, it will have implications for the current regime of public flood management and for residential vulnerability to flood hazards. This paper engages many of the competing issues surrounding the privatization of flood risk by addressing questions about whether flood insurance can be an effective tool in limiting exposure to the hazard and how it would exacerbate already unequal vulnerability. A case study investigates willingness to pay for flood insurance among residents in Metro Vancouver and how attitudes about insurance relate to other factors that determine residential vulnerability to flood hazards. Findings indicate that demand for flood insurance is part of a complex, dialectical set of determinants of vulnerability.

  3. Flood insurance in Canada: implications for flood management and residential vulnerability to flood hazards.

    PubMed

    Oulahen, Greg

    2015-03-01

    Insurance coverage of damage caused by overland flooding is currently not available to Canadian homeowners. As flood disaster losses and water damage claims both trend upward, insurers in Canada are considering offering residential flood coverage in order to properly underwrite the risk and extend their business. If private flood insurance is introduced in Canada, it will have implications for the current regime of public flood management and for residential vulnerability to flood hazards. This paper engages many of the competing issues surrounding the privatization of flood risk by addressing questions about whether flood insurance can be an effective tool in limiting exposure to the hazard and how it would exacerbate already unequal vulnerability. A case study investigates willingness to pay for flood insurance among residents in Metro Vancouver and how attitudes about insurance relate to other factors that determine residential vulnerability to flood hazards. Findings indicate that demand for flood insurance is part of a complex, dialectical set of determinants of vulnerability.

  4. Miscibility of nifedipine and hydrophilic polymers as measured by (1)H-NMR spin-lattice relaxation.

    PubMed

    Aso, Yukio; Yoshioka, Sumie; Miyazaki, Tamaki; Kawanishi, Tohru; Tanaka, Kazuyuki; Kitamura, Satoshi; Takakura, Asako; Hayashi, Takashi; Muranushi, Noriyuki

    2007-08-01

    The miscibility of a drug with excipients in solid dispersions is considered to be one of the most important factors for preparation of stable amorphous solid dispersions. The purpose of the present study was to elucidate the feasibility of (1)H-NMR spin-lattice relaxation measurements to assess the miscibility of a drug with excipients. Solid dispersions of nifedipine with the hydrophilic polymers poly(vinylpyrrolidone) (PVP), hydroxypropylmethylcellulose (HPMC) and alpha,beta-poly(N-5-hydroxypentyl)-L-aspartamide (PHPA) with various weight ratios were prepared by spray drying, and the spin-lattice relaxation decay of the solid dispersions in a laboratory frame (T(1) decay) and in a rotating frame (T(1rho) decay) were measured. T(1rho) decay of nifedipine-PVP solid dispersions (3 : 7, 5 : 5 and 7 : 3) was describable with a mono-exponential equation, whereas T(1rho) decay of nifedipine-PHPA solid dispersions (3 : 7, 4 : 6 and 5 : 5) was describable with a bi-exponential equation. Because a mono-exponential T(1rho) decay indicates that the domain sizes of nifedipine and polymer in solid dispersion are less than several nm, it is speculated that nifedipine is miscible with PVP but not miscible with PHPA. All the nifedipine-PVP solid dispersions studied showed a single glass transition temperature (T(g)), whereas two glass transitions were observed for the nifedipine-PHPA solid dispersion (3 : 7), thus supporting the above speculation. For nifedipine-HPMC solid dispersions (3 : 7 and 5 : 5), the miscibility of nifedipine and HPMC could not be determined by DSC measurements due to the lack of obviously evident T(g). In contrast, (1)H-NMR spin-lattice relaxation measurements showed that nifedipine and HPMC are miscible, since T(1rho) decay of the solid dispersions (3 : 7, 5 : 5 and 7 : 3) was describable with a mono-exponential equation. These results indicate that (1)H-NMR spin-lattice relaxation measurements are useful for assessing the miscibility of a drug and an

  5. A European Flood Database: facilitating comprehensive flood research beyond administrative boundaries

    NASA Astrophysics Data System (ADS)

    Hall, J.; Arheimer, B.; Aronica, G. T.; Bilibashi, A.; Boháč, M.; Bonacci, O.; Borga, M.; Burlando, P.; Castellarin, A.; Chirico, G. B.; Claps, P.; Fiala, K.; Gaál, L.; Gorbachova, L.; Gül, A.; Hannaford, J.; Kiss, A.; Kjeldsen, T.; Kohnová, S.; Koskela, J. J.; Macdonald, N.; Mavrova-Guirguinova, M.; Ledvinka, O.; Mediero, L.; Merz, B.; Merz, R.; Molnar, P.; Montanari, A.; Osuch, M.; Parajka, J.; Perdigão, R. A. P.; Radevski, I.; Renard, B.; Rogger, M.; Salinas, J. L.; Sauquet, E.; Šraj, M.; Szolgay, J.; Viglione, A.; Volpi, E.; Wilson, D.; Zaimi, K.; Blöschl, G.

    2015-06-01

    The current work addresses one of the key building blocks towards an improved understanding of flood processes and associated changes in flood characteristics and regimes in Europe: the development of a comprehensive, extensive European flood database. The presented work results from ongoing cross-border research collaborations initiated with data collection and joint interpretation in mind. A detailed account of the current state, characteristics and spatial and temporal coverage of the European Flood Database, is presented. At this stage, the hydrological data collection is still growing and consists at this time of annual maximum and daily mean discharge series, from over 7000 hydrometric stations of various data series lengths. Moreover, the database currently comprises data from over 50 different data sources. The time series have been obtained from different national and regional data sources in a collaborative effort of a joint European flood research agreement based on the exchange of data, models and expertise, and from existing international data collections and open source websites. These ongoing efforts are contributing to advancing the understanding of regional flood processes beyond individual country boundaries and to a more coherent flood research in Europe.

  6. Climatic and geomorphic controls on flash flood response in Europe

    NASA Astrophysics Data System (ADS)

    Marchi, Lorenzo; Borga, Marco; Preciso, Emanuele; Gaume, Eric

    2010-05-01

    High-resolution data enabling identification and analysis of the hydrometeorological causative processes of flash floods have been collected and analysed for 25 extreme flash floods (60 drainage basins) across Europe. Criteria for flood selection were high intensity of triggering rainfall and flood response and availability of reliable high-resolution data. Hydrometeorological data collected for each event were checked by using a hydrological model. The derivation and analysis of summarising variables has made it possible to outline some characteristics of flash floods in various morphoclimatic regions of Europe. Peak discharge data for more than 50% of the studied watersheds derive from post-flood surveys in ungauged streams. This stresses both the significance of post-flood surveys in building and extending flash flood databases, and the need to develop new methods for flash-flood hazard assessment able to take into account data from post-event analysis. Catchments do not need to be particularly steep to favour flash flooding. However, relief is important since it may affect flash flood occurrence in specific catchments by combination of two main mechanisms: orographic effects augmenting precipitation and anchoring convection, and topographic relief promoting rapid concentration of streamflow. Examination of data shows a peculiar seasonality effect on flash flood occurrence, with events in the Mediterranean and Alpine-Mediterranean regions mostly occurring in autumn, whereas events in the inland Continental region commonly occur in summer, revealing different climatic forcing. Consistently with this seasonality effect, spatial extent and duration of the events is generally smaller for the Continental events with respect to those occurring in the Mediterranean region. Furthermore, the flash flood regime is usually more intense in the Mediterranean Region than in the Continental areas. The runoff coefficients of the studied flash floods are usually rather low (mean

  7. Development of flood index by characterisation of flood hydrographs

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Biswa; Suman, Asadusjjaman

    2015-04-01

    In recent years the world has experienced deaths, large-scale displacement of people, billions of Euros of economic damage, mental stress and ecosystem impacts due to flooding. Global changes (climate change, population and economic growth, and urbanisation) are exacerbating the severity of flooding. The 2010 floods in Pakistan and the 2011 floods in Australia and Thailand demonstrate the need for concerted action in the face of global societal and environmental changes to strengthen resilience against flooding. Due to climatological characteristics there are catchments where flood forecasting may have a relatively limited role and flood event management may have to be trusted upon. For example, in flash flood catchments, which often may be tiny and un-gauged, flood event management often depends on approximate prediction tools such as flash flood guidance (FFG). There are catchments fed largely by flood waters coming from upstream catchments, which are un-gauged or due to data sharing issues in transboundary catchments the flow of information from upstream catchment is limited. Hydrological and hydraulic modelling of these downstream catchments will never be sufficient to provide any required forecasting lead time and alternative tools to support flood event management will be required. In FFG, or similar approaches, the primary motif is to provide guidance by synthesising the historical data. We follow a similar approach to characterise past flood hydrographs to determine a flood index (FI), which varies in space and time with flood magnitude and its propagation. By studying the variation of the index the pockets of high flood risk, requiring attention, can be earmarked beforehand. This approach can be very useful in flood risk management of catchments where information about hydro-meteorological variables is inadequate for any forecasting system. This paper presents the development of FI and its application to several catchments including in Kentucky in the USA

  8. Nogales flood detention study

    USGS Publications Warehouse

    Norman, Laura M.; Levick, Lainie; Guertin, D. Phillip; Callegary, James; Guadarrama, Jesus Quintanar; Anaya, Claudia Zulema Gil; Prichard, Andrea; Gray, Floyd; Castellanos, Edgar; Tepezano, Edgar; Huth, Hans; Vandervoet, Prescott; Rodriguez, Saul; Nunez, Jose; Atwood, Donald; Granillo, Gilberto Patricio Olivero; Ceballos, Francisco Octavio Gastellum

    2010-01-01

    Flooding in Ambos Nogales often exceeds the capacity of the channel and adjacent land areas, endangering many people. The Nogales Wash is being studied to prevent future flood disasters and detention features are being installed in tributaries of the wash. This paper describes the application of the KINEROS2 model and efforts to understand the capacity of these detention features under various flood and urbanization scenarios. Results depict a reduction in peak flow for the 10-year, 1-hour event based on current land use in tributaries with detention features. However, model results also demonstrate that larger storm events and increasing urbanization will put a strain on the features and limit their effectiveness.

  9. Nanoscale Infrared, Thermal, and Mechanical Characterization of Telaprevir-Polymer Miscibility in Amorphous Solid Dispersions Prepared by Solvent Evaporation.

    PubMed

    Li, Na; Taylor, Lynne S

    2016-03-07

    Miscibility is of great interest for pharmaceutical systems, in particular, for amorphous solid dispersions, as phase separation can lead to a higher tendency to crystallize, resulting in a loss in solubility, decreased dissolution rate, and compromised bioavailability. The purpose of this study was to investigate the miscibility behavior of a model poorly water-soluble drug, telaprevir (TPV), with three different polymers using atomic force microscopy-based infrared, thermal, and mechanical analysis. Standard atomic force microscopy (AFM) imaging together with nanoscale infrared spectroscopy (AFM-IR), nanoscale thermal analysis (nanoTA), and Lorentz contact resonance (LCR) measurements were used to evaluate the miscibility behavior of TPV with three polymers, hydroxypropyl methylcellulose (HPMC), HPMC acetate succinate (HPMCAS), and poly(vinylpyrrolidone-co-vinyl acetate) (PVPVA), at different drug to polymer ratios. Phase separation was observed with HPMC and PVPVA at drug loadings above 10%. For HPMCAS, a smaller miscibility gap was observed, with phase separation being observed at drug loadings higher than ∼30-40%. The domain size of phase-separated regions varied from below 50 nm to a few hundred nanometers. Localized infrared spectra, nano-TA measurements, images from AFM-based IR, and LCR measurements showed clear contrast between the continuous and discrete domains for these phase-separated systems, whereby the discrete domains were drug-rich. Fluorescence microscopy provided additional evidence for phase separation. These methods appear to be promising to evaluate miscibility in drug-polymer systems with similar Tgs and submicron domain sizes. Furthermore, such findings are of obvious importance in the context of contributing to a mechanistic understanding of amorphous solid dispersion phase behavior.

  10. Miscibility studies of Polyethylene Glycol with Polystyrene in Toluene by Various Physical and Advanced Techniques

    NASA Astrophysics Data System (ADS)

    Padmanaban, R.; Venkatramanan, K.

    2016-10-01

    Polyethylene glycol (PEG) is a chemical that has an extensive variety of applications in the world of medicine. It is used as a base to manufacture certain medicines, assist in drug delivery, and is also used as an agent in some medical procedures. It is an osmotic laxative. Polyethylene glycol works by retaining water in the stool, resulting in softer stools and more frequent bowel movements. Polyethylene glycol does not affect glucose and electrolytes in the body. PEG refers to a hydrocarbon molecule that can have a variable size, and different sizes can have different physical properties, giving this compound a great deal of flexibility in its application. In the present study, Polyethylene Glycol (PEG) (Molar mass: 1500) is blended with Polystyrene (PS) (Molar mass: 35000) in Toluene. The miscibility nature of the poly blend is analyzed by Ultrasonic velocity, viscosity, density and refractive index techniques at 303K. The compatibility nature of the blend is confirmed by Differential Scanning Calorimetry (DSC) studies.

  11. Evaporation dynamics of a liquid drop on a non-miscible liquid bath

    NASA Astrophysics Data System (ADS)

    Pirat, Christophe; Ramos-Canut, Stella; Caupin, Frederic; wetting Team

    2016-11-01

    When a liquid drop sits on a solid surface, it is well known that the wetting and evaporation properties strongly depend on the environmental and wetting conditions. In this experimental study, we investigate the coupled spreading-evaporation dynamics of a liquid drop, made of a mixture of water and ethanol, gently deposited on a non-miscible oil bath. After a fast spreading stage due to a positive spreading parameter, the drop starts to recede while the evaporation is going on. Subsequently, a Marangoni instability develops as alcohol evaporates faster than water. In particular, depending on the initial alcohol-water ratio, a set of rim instabilities takes place. Radial droplet ejections can be observed, with various droplet speeds, sizes and frequencies.

  12. Countersuperflow instability in miscible two-component Bose-Einstein condensates

    SciTech Connect

    Ishino, Shungo; Tsubota, Makoto; Takeuchi, Hiromitsu

    2011-06-15

    We study theoretically the instability of countersuperflow, i.e., two counterpropagating miscible superflows, in uniform two-component Bose-Einstein condensates. Countersuperflow instability causes mutual friction between the superfluids, causing a momentum exchange between the two condensates, when the relative velocity of the counterflow exceeds a critical value. The momentum exchange leads to nucleation of vortex rings from characteristic density patterns due to the nonlinear development of the instability. Expansion of the vortex rings drastically accelerates the momentum exchange, leading to a highly nonlinear regime caused by intervortex interaction and vortex reconnection between the rings. For a sufficiently large interaction between the two components, rapid expansion of the vortex rings causes isotropic turbulence and the global relative motion of the two condensates relaxes. The maximum vortex line density in the turbulence is proportional to the square of the relative velocity.

  13. Three-dimensional miscible, porous media displacements for the quarter five-spot configuration

    NASA Astrophysics Data System (ADS)

    Riaz, Amir

    Three-dimensional miscible displacements with gravity override are investigated in homogeneous and heterogeneous porous media using high accuracy numerical simulations. Special emphasis is placed on the interpretation of the dynamics in terms of the vorticity production related to viscosity, permeability and gravity. Comparison with experimental results show that three-dimensional neutrally buoyant displacements give a better estimate of the displacement efficiency than two-dimensional displacements. Gravity override profoundly influences the flow dynamics both by creating a gravity layer where most of the displaced fluid is bypassed as well as by enhancing the horizontal and vertical mode interactions. Heterogeneous displacements are classified into regimes of viscous fingering, harmonic resonance and channeling depending upon the relative magnitudes of the viscous and permeability length scales. A complex coupling between the viscous instability and permeability spectra leads to intricate fingering patterns that profoundly influence the displacement efficiency.

  14. Wavelength Analysis of Interface between Two Miscible Solutions Observed in Formation of Fractal Pattern

    NASA Astrophysics Data System (ADS)

    Shimokawa, Michiko; Takami, Toshiya

    2014-04-01

    When a droplet of a higher-density solution (HDS) is placed on top of a lower-density solution (LDS), the HDS draws a fractal pattern on the surface of the LDS. Before the fractal pattern is formed, a stick-like pattern with a periodic structure emerges in a region surrounding the surface pattern due to interfacial instability. We experimentally measure the wavelength of this stick-like pattern. The wavelength increases with the volume of the HDS and is independent of the viscosities of the two solutions. To understand the stick generation, we propose a model of miscible viscous fingering whose boundary conditions are similar to those of the experiments. The wavelength obtained from the model agrees with the experimentally obtained wavelength. The formation of the fractal pattern is discussed by comparing it with the viscous fingering.

  15. Adaptive enriched Galerkin methods for miscible displacement problems with entropy residual stabilization

    NASA Astrophysics Data System (ADS)

    Lee, Sanghyun; Wheeler, Mary F.

    2017-02-01

    We present a novel approach to the simulation of miscible displacement by employing adaptive enriched Galerkin finite element methods (EG) coupled with entropy residual stabilization for transport. In particular, numerical simulations of viscous fingering instabilities in heterogeneous porous media and Hele-Shaw cells are illustrated. EG is formulated by enriching the conforming continuous Galerkin finite element method (CG) with piecewise constant functions. The method provides locally and globally conservative fluxes, which are crucial for coupled flow and transport problems. Moreover, EG has fewer degrees of freedom in comparison with discontinuous Galerkin (DG) and an efficient flow solver has been derived which allows for higher order schemes. Dynamic adaptive mesh refinement is applied in order to reduce computational costs for large-scale three dimensional applications. In addition, entropy residual based stabilization for high order EG transport systems prevents spurious oscillations. Numerical tests are presented to show the capabilities of EG applied to flow and transport.

  16. Theoretical study of miscibility and glass-forming trends in mixtures of polystyrene spheres

    NASA Technical Reports Server (NTRS)

    Shih, W.-H.; Stroud, D.

    1984-01-01

    A theoretical study of glass-forming trends and miscibility in mixtures of polystyrene spheres (polyballs) of different diameters, suspended in an aqueous solution, is presented. The polyballs are assumed to be charged and to interact via a Debye-Hueckel screened Coulomb potential. The Helmholtz free energy is calculated from a variational principle based on the Gibbs-Bogoliubov inequality, in which a mixture of hard spheres of different diameters is chosen as the reference system. It is found that when the charges of the two types of polyballs are sufficiently different, the variationally determined ratio of hard-sphere diameters differs substantially, leading to packing difficulties characteristic of glass formation. The experimentally observed range of glass formation corresponds to a ratio of hard-sphere diameters of 0.8 or less. Calculations of the free energy as a function of concentration indicate that the liquid polyball mixture is stable against the phase separation, even for widely different polyball charges.

  17. Experimental study of the growth of mixing zone in miscible viscous fingering

    NASA Astrophysics Data System (ADS)

    Malhotra, Sahil; Sharma, Mukul M.; Lehman, Eric R.

    2015-01-01

    An experimental study is performed to quantify the growth of the mixing zone in miscible viscous fingering. Rectilinear flow displacement experiments are performed in a Hele-Shaw cell over a wide range of viscosity ratios (1-1225) by injecting water into glycerol solutions at different flow rates. All the experiments are performed at high Peclet numbers and linear growth in mixing zone is observed. The mixing zone velocity increases with the viscosity ratio up to viscosity ratios of 340 and the trend is consistent with Koval's model. However, at higher viscosity ratios, the mixing velocity plateaus signifying no further effect of viscosity contrast on the growth of mixing zone. The front (fingertip) velocities also increase up to viscosity ratios of 340 above which the velocities plateau.

  18. Polymer collapse in miscible good solvents is a generic phenomenon driven by preferential adsorption

    NASA Astrophysics Data System (ADS)

    Mukherji, Debashish; Marques, Carlos M.; Kremer, Kurt

    2014-09-01

    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.

  19. 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.

  20. 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.

  1. Flood hazard assessment in areas prone to flash flooding

    NASA Astrophysics Data System (ADS)

    Kvočka, Davor; Falconer, Roger A.; Bray, Michaela

    2016-04-01

    Contemporary climate projections suggest that there will be an increase in the occurrence of high-intensity rainfall events in the future. These precipitation extremes are usually the main cause for the emergence of extreme flooding, such as flash flooding. Flash floods are among the most unpredictable, violent and fatal natural hazards in the world. Furthermore, it is expected that flash flooding will occur even more frequently in the future due to more frequent development of extreme weather events, which will greatly increase the danger to people caused by flash flooding. This being the case, there will be a need for high resolution flood hazard maps in areas susceptible to flash flooding. This study investigates what type of flood hazard assessment methods should be used for assessing the flood hazard to people caused by flash flooding. Two different types of flood hazard assessment methods were tested: (i) a widely used method based on an empirical analysis, and (ii) a new, physically based and experimentally calibrated method. Two flash flood events were considered herein, namely: the 2004 Boscastle flash flood and the 2007 Železniki flash flood. The results obtained in this study suggest that in the areas susceptible to extreme flooding, the flood hazard assessment should be conducted using methods based on a mechanics-based analysis. In comparison to standard flood hazard assessment methods, these physically based methods: (i) take into account all of the physical forces, which act on a human body in floodwater, (ii) successfully adapt to abrupt changes in the flow regime, which often occur for flash flood events, and (iii) rapidly assess a flood hazard index in a relatively short period of time.

  2. Flooding the market

    NASA Astrophysics Data System (ADS)

    Horn, Diane; McShane, Michael

    2013-11-01

    A flood insurance market with risk-based prices in the UK will only stimulate climate change adaptation if it is part of a wider strategy that includes land-use planning, building regulations and water management.

  3. Floods and Mold Growth

    EPA Pesticide Factsheets

    Mold growth may be a problem after flooding. Excess moisture in the home is cause for concern about indoor air quality primarily because it provides breeding conditions for pests, molds and other microorganisms.

  4. Localized Flood Management

    EPA Pesticide Factsheets

    practitioners will cover a range of practices that can help communities build flood resilience, from small scale interventions such as rain gardens and permeable pavement to coordinated open space and floodplain preservation

  5. Japan: Tsunami Flooding

    Atmospheric Science Data Center

    2013-04-16

    ... article title:  Lingering Floods from Tohoku-oki Earthquake Tsunami     View Larger Image The March 11, 2011 Tohoku-oki earthquake triggered a deadly and destructive tsunami whose impacts were felt ...

  6. Assessing Flood Mitigation Alternatives in Brezovička Village in Slovakia

    NASA Astrophysics Data System (ADS)

    Zvijáková, Lenka; Zeleňáková, Martina

    2013-06-01

    Flooding due to extreme rain events in urban environments is a problem and a growing concern. There is an increasing demand for a new paradigm to improve flood-mitigation decision processes that calls for riskreduction strategies at several levels. Therefore is a challenge in assessing and comparing different flood mitigation measures. The aim of this paper is to explore a new method to improve an environmental impact assessment of flood-mitigation measures in decision processes by risk analysis method.

  7. Modeling of Flood Risk for the Continental United States

    NASA Astrophysics Data System (ADS)

    Lohmann, D.; Li, S.; Katz, B.; Goteti, G.; Kaheil, Y. H.; Vojjala, R.

    2011-12-01

    The science of catastrophic risk modeling helps people to understand the physical and financial implications of natural catastrophes (hurricanes, flood, earthquakes, etc.), terrorism, and the risks associated with changes in life expectancy. As such it depends on simulation techniques that integrate multiple disciplines such as meteorology, hydrology, structural engineering, statistics, computer science, financial engineering, actuarial science, and more in virtually every field of technology. In this talk we will explain the techniques and underlying assumptions of building the RMS US flood risk model. We especially will pay attention to correlation (spatial and temporal), simulation and uncertainty in each of the various components in the development process. Recent extreme floods (e.g. US Midwest flood 2008, US Northeast flood, 2010) have increased the concern of flood risk. Consequently, there are growing needs to adequately assess the flood risk. The RMS flood hazard model is mainly comprised of three major components. (1) Stochastic precipitation simulation module based on a Monte-Carlo analogue technique, which is capable of producing correlated rainfall events for the continental US. (2) Rainfall-runoff and routing module. A semi-distributed rainfall-runoff model was developed to properly assess the antecedent conditions, determine the saturation area and runoff. The runoff is further routed downstream along the rivers by a routing model. Combined with the precipitation model, it allows us to correlate the streamflow and hence flooding from different rivers, as well as low and high return-periods across the continental US. (3) Flood inundation module. It transforms the discharge (output from the flow routing) into water level, which is further combined with a two-dimensional off-floodplain inundation model to produce comprehensive flood hazard map. The performance of the model is demonstrated by comparing to the observation and published data. Output from

  8. Urban flood risk warning under rapid urbanization.

    PubMed

    Chen, Yangbo; Zhou, Haolan; Zhang, Hui; Du, Guoming; Zhou, Jinhui

    2015-05-01

    In the past decades, China has observed rapid urbanization, the nation's urban population reached 50% in 2000, and is still in steady increase. Rapid urbanization in China has an adverse impact on urban hydrological processes, particularly in increasing the urban flood risks and causing serious urban flooding losses. Urban flooding also increases health risks such as causing epidemic disease break out, polluting drinking water and damaging the living environment. In the highly urbanized area, non-engineering measurement is the main way for managing urban flood risk, such as flood risk warning. There is no mature method and pilot study for urban flood risk warning, the purpose of this study is to propose the urban flood risk warning method for the rapidly urbanized Chinese cities. This paper first presented an urban flood forecasting model, which produces urban flood inundation index for urban flood risk warning. The model has 5 modules. The drainage system and grid dividing module divides the whole city terrain into drainage systems according to its first-order river system, and delineates the drainage system into grids based on the spatial structure with irregular gridding technique; the precipitation assimilation module assimilates precipitation for every grids which is used as the model input, which could either be the radar based precipitation estimation or interpolated one from rain gauges; runoff production module classifies the surface into pervious and impervious surface, and employs different methods to calculate the runoff respectively; surface runoff routing module routes the surface runoff and determines the inundation index. The routing on surface grid is calculated according to the two dimensional shallow water unsteady flow algorithm, the routing on land channel and special channel is calculated according to the one dimensional unsteady flow algorithm. This paper then proposed the urban flood risk warning method that is called DPSIR model based

  9. 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.

  10. National Flood Interoperability Experiment

    NASA Astrophysics Data System (ADS)

    Maidment, D. R.

    2014-12-01

    The National Flood Interoperability Experiment is led by the academic community in collaboration with the National Weather Service through the new National Water Center recently opened on the Tuscaloosa campus of the University of Alabama. The experiment will also involve the partners in IWRSS (Integrated Water Resources Science and Services), which include the USGS, the Corps of Engineers and FEMA. The experiment will address the following questions: (1) How can near-real-time hydrologic forecasting at high spatial resolution, covering the nation, be carried out using the NHDPlus or next generation geofabric (e.g. hillslope, watershed scales)? (2) How can this lead to improved emergency response and community resilience? (3) How can improved an improved interoperability framework support the first two goals and lead to sustained innovation in the research to operations process? The experiment will run from September 2014 through August 2015, in two phases. The mobilization phase from September 2014 until May 2015 will assemble the components of the interoperability framework. A Summer Institute to integrate the components will be held from June to August 2015 at the National Water Center involving faculty and students from the University of Alabama and other institutions coordinated by CUAHSI. It is intended that the insight that arises from this experiment will help lay the foundation for a new national scale, high spatial resolution, near-real-time hydrologic simulation system for the United States.

  11. On the significance of future trends in flood frequencies

    NASA Astrophysics Data System (ADS)

    Bernhardt, M.; Schulz, K.; Wieder, O.

    2015-12-01

    Floods are a significant threat for alpine headwater catchments and for the forelands. The formation of significant flood events is thereby often coupled on processes occurring in the alpine zone. Rain on snow events are just one example. The prediction of flood risks or trends of flood risks is of major interest to people under direct threat, policy and decision makers as well as for insurance companies. A lot of research was and is currently done in view of detecting future trends in flood extremes or return periods. From a pure physically based point of view, there is strong evidence that those trends exist. But, the central point question is if trends in flood events or other extreme events could be detected from a statistical point of view and on the basis of the available data. This study will investigate this question on the basis of different target parameters and by using long term measurements.

  12. Measuring flood footprint of a regional economy - A case study for the UK flooding

    NASA Astrophysics Data System (ADS)

    Guan, D.

    2013-12-01

    Analysis of the urban economy and society is central to understanding the broad impacts of flooding and to identify cost-effective adaptation and mitigation measures. Assessments of the flooding impacts on cities have traditionally focused on the initial impact on people and assets. These initial estimates (so-called ';direct damage') are useful both in understanding the immediate implications of damage, and in marshalling the pools of capital and supplies required for re-building after an event. Since different economies as well as societies are coupled, especially under the current economic crisis, any small-scale damage may be multiplied and cascaded throughout wider economic systems and social networks. The direct and indirect damage is currently not evaluated well and could be captured by quantification of what we call the flood footprint. Flooding in one location can impact the whole UK economy. Neglecting these knock-on costs (i.e. the true footprint of the flood) means we might be ignoring the economic benefits and beneficiaries of flood risk management interventions. In 2007, for example, floods cost the economy about £3.2 bn directly, but the wider effect might actually add another 50% to 250% to that. Flood footprint is a measure of the exclusive total socioeconomic impact that is directly and indirectly caused by a flood event to the flooding region and wider economic systems and social networks. We adopt the UK 2012 flooding. An input-output basic dynamic inequalities (BDI) model is used to assess the impact of the floodings on the level of a Yorkshire economy, accounting for interactions between industries through demand and supply of intermediate consumption goods with a circular flow. After the disaster the economy will be unbalanced. The recovery process finishes when the economy is completely balance, i.e., when labour production capacity equals demands and production and all the variables reach pre-disaster levels. The analysis is carried out

  13. Preparing for floods: flood forecasting and early warning

    NASA Astrophysics Data System (ADS)

    Cloke, Hannah

    2016-04-01

    Flood forecasting and early warning has continued to stride ahead in strengthening the preparedness phases of disaster risk management, saving lives and property and reducing the overall impact of severe flood events. For example, continental and global scale flood forecasting systems such as the European Flood Awareness System and the Global Flood Awareness System provide early information about upcoming floods in real time to various decisionmakers. Studies have found that there are monetary benefits to implementing these early flood warning systems, and with the science also in place to provide evidence of benefit and hydrometeorological institutional outlooks warming to the use of probabilistic forecasts, the uptake over the last decade has been rapid and sustained. However, there are many further challenges that lie ahead to improve the science supporting flood early warning and to ensure that appropriate decisions are made to maximise flood preparedness.

  14. Flood resilience and uncertainty in flood risk assessment

    NASA Astrophysics Data System (ADS)

    Beven, K.; Leedal, D.; Neal, J.; Bates, P.; Hunter, N.; Lamb, R.; Keef, C.

    2012-04-01

    Flood risk assessments do not normally take account of the uncertainty in assessing flood risk. There is no requirement in the EU Floods Directive to do so. But given the generally short series (and potential non-stationarity) of flood discharges, the extrapolation to smaller exceedance potentials may be highly uncertain. This means that flood risk mapping may also be highly uncertainty, with additional uncertainties introduced by the representation of flood plain and channel geometry, conveyance and infrastructure. This suggests that decisions about flood plain management should be based on exceedance probability of risk rather than the deterministic hazard maps that are common in most EU countries. Some examples are given from 2 case studies in the UK where a framework for good practice in assessing uncertainty in flood risk mapping has been produced as part of the Flood Risk Management Research Consortium and Catchment Change Network Projects. This framework provides a structure for the communication and audit of assumptions about uncertainties.

  15. Validation of a global hydrodynamic flood inundation model against high resolution observation data of urban flooding

    NASA Astrophysics Data System (ADS)

    Bates, Paul; Sampson, Chris; Smith, Andy; Neal, Jeff

    2015-04-01

    In this work we present further validation results for a hyper-resolution global flood inundation model. We use a true hydrodynamic model that uses highly efficient numerical algorithms (LISFLOOD-FP) to simulate flood inundation at ~1km resolution globally and then use downscaling algorithms to determine flood extent and water depth at 3 seconds of arc spatial resolution (~90m at the equator). The global model has ~150 million cells and requires ~180 hours of CPU time for a 10 year simulation period. Terrain data are taken from a custom version of the SRTM data set that has been processed specifically for hydrodynamic modelling. Return periods of flood flows along the entire global river network are determined using: (1) empirical relationships between catchment characteristics and index flood magnitude in different hydroclimatic zones derived from global runoff data; and (2) an index flood growth curve, also empirically derived. Bankful return period flow is then used to set channel width and depth, and flood defence impacts are modelled using empirical relationships between GDP, urbanization and defence standard of protection. The results of these simulations are global flood hazard maps for a number of different return period events from 1 in 5 to 1 in 1000 years. This method has already been show to compare well to return period flood hazard maps derived from models built with high resolution and accuracy local data (Sampson et al., submitted), yet the output from the global flood model has not yet been compared to real flood observations. Whilst the spatial resolution of the global model is high given the size of the model domain, ~1km resolution is still coarse compared to the models typically used to simulate urban flooding and the data typically used to validate these (~25m or less). Comparison of the global model to real-world observations or urban flooding therefore represents an exceptionally stringent test of model skill. In this paper we therefore

  16. Miscibility study of carbon dioxide injection to enhance oil recovery from Abu-Dhabi oil field Thani reservoire

    NASA Astrophysics Data System (ADS)

    Aljarwan, Abdulla Humaid Saif Saeed

    The subject field in this study has been recognized among the largest offshore oil fields in the world, located in the Arabian Gulf 63 kilometers to the Northwest of Abu Dhabi, producing large quantities of crude oil and associated gas from three different carbonate reservoirs, Thani-I, II and IIII since 1963. In the early 1970's peripheral water injection scheme was adopted to maintain the reservoir pressure and sustain production. Simultaneously, partial waterflooding was applied to one sector of the field, but stopped soon after implementation shadowed by poor sweep efficiency and dramatic escalation of water-cut. Furthermore, hydrocarbon miscible gas injection was implemented in the year 2000 but stopped seven years later, due to high gas oil ratio and aspheltene deposition. In light of such recovery complications, management is considering serious recovery measures to extend plateau production and meet long-term production from this field. Post initial screening phase, it became evident that CO 2 miscible injection is the most suitable way forward. Characteristics of the Thani-III reservoir are within the favorable range for both immiscible and miscible CO2 injection criteria set by Taber, Martine and Serigh. Thani-III reservoir is considered more homogenous, less fractured and with higher production potential than Thani-I and II, hence promoted to be the target of CO2 miscible gas injection. This thesis aims to study the miscibility features of CO2 miscible injecton to enhanced oil recovery from Thani-III reservoir. Comprehensive simulation model is used to determine multi contact miscibility and suitable equation of state with CO2 as a separate pseudo component using one of the industry standard simulation software. Experimental PVT data for bottom hole and separator samples including compositional analysis, differential liberation test, separator tests, constant composition expansion, viscosity measurements and swelling tests for pure CO2 were used to

  17. Probabilistic modelling of flood events using the entropy copula

    NASA Astrophysics Data System (ADS)

    Li, Fan; Zheng, Qian

    2016-11-01

    The estimation of flood frequency is vital for the flood control strategies and hydraulic structure design. Generating synthetic flood events according to statistical properties of observations is one of plausible methods to analyze the flood frequency. Due to the statistical dependence among the flood event variables (i.e. the flood peak, volume and duration), a multidimensional joint probability estimation is required. Recently, the copula method is widely used for multivariable dependent structure construction, however, the copula family should be chosen before application and the choice process is sometimes rather subjective. The entropy copula, a new copula family, employed in this research proposed a way to avoid the relatively subjective process by combining the theories of copula and entropy. The analysis shows the effectiveness of the entropy copula for probabilistic modelling the flood events of two hydrological gauges, and a comparison of accuracy with the popular copulas was made. The Gibbs sampling technique was applied for trivariate flood events simulation in order to mitigate the calculation difficulties of extending to three dimension directly. The simulation results indicate that the entropy copula is a simple and effective copula family for trivariate flood simulation.

  18. Flood hazard and risk analysis in the southwest region of Bangladesh

    NASA Astrophysics Data System (ADS)

    Tingsanchali, Tawatchai; Fazlul Karim, Mohammed

    2005-06-01

    Flood hazard and risk assessment was conducted to identify the priority areas in the southwest region of Bangladesh for flood mitigation. Simulation of flood flow through the Gorai and Arial Khan river system and its floodplains was done by using a hydrodynamic model. After model calibration and verification, the model was used to simulate the flood flow of 100-year return period for a duration of four months. The maximum flooding depths at different locations in the rivers and floodplains were determined. The process in determining long flooding durations at every grid point in the hydrodynamic model is laborious and time-consuming. Therefore the flood durations were determined by using satellite images of the observed flood in 1988, which has a return period close to 100 years. Flood hazard assessment was done considering flooding depth and duration. By dividing the study area into smaller land units for hazard assessment, the hazard index and the hazard factor for each land unit for depth and duration of flooding were determined. From the hazard factors of the land units, a flood hazard map, which indicates the locations of different categories of hazard zones, was developed. It was found that 54% of the study area was in the medium hazard zone, 26% in the higher hazard zone and 20% in the lower hazard zone. Due to lack of sufficient flood damage data, flood damage vulnerability is simply considered proportional to population density. The flood risk factor of each land unit was determined as the product of the flood hazard factor and the vulnerability factor. Knowing the flood risk factors for the land units, a flood risk map was developed based on the risk factors. These maps are very useful for the inhabitants and floodplain management authorities to minimize flood damage and loss of human lives.

  19. Progress towards regional flash flood modelling

    NASA Astrophysics Data System (ADS)

    Bates, P. D.; Coxon, G.; Quinn, N.; Freer, J. E.

    2015-12-01

    Flash flooding causes widespread disruption and damage across the UK, with recent research indicating that the occurrence and severity of intense rainfall is likely to increase in the future. To date, our ability to model such events at anything other than local scales has been hindered both by a lack of data at adequate spatial and temporal resolutions and a limited understanding of the processes involved in flooding from short duration, high intensity rainfall events. To enable effective flood risk management and decisions, it is essential that we improve our understanding of the variability in risk from such events across the UK and this requires an ability to undertake flash flood modelling at regional scales. In this study, we have implemented a coupled hydrological - hydrodynamic model for the representation of flash flooding at regional scales over long durations. To provide inputs to these models, we have developed a gridded sub-daily (hourly) rainfall record of the UK from 1993 to 2011. This enables us to more accurately represent flooding resulting from short duration rainfall events that are poorly represented by commonly utilised daily rainfall data. For a given region of interest we cascade rainfall estimates from our sub-daily dataset into a semi-distributed hydrological model (Dynamic Topmodel) in order to generate river discharge estimates which are then used to force a widely utilised inundation model (LISFLOOD-FP). Here we present the results from a test case in order to demonstrate the capabilities of the modelling framework over a variety of events with differing characteristics. The results will provide an insight into our capabilities of representing flash flooding and highlight key areas for future model development and enhanced process understanding.

  20. Drug-polymer miscibility across a spray dryer: a case study of naproxen and miconazole solid dispersions.

    PubMed

    Worku, Zelalem Ayenew; Aarts, Jolie; Singh, Abhishek; Van den Mooter, Guy

    2014-04-07

    The structural and physical stability of solid dispersions have not been adequately explored during spray drying manufacturing processes. In this study a wide range of compositions of naproxen/PVP-VA 64 (poly(1-vinylpyrrolidone-co-vinyl acetate)) and miconazole/PVP-VA 64 solid dispersions prepared by different laboratory spray dryers were collected from various selected locations and used to investigate the drug-polymer mixing across spray dryers. Spray-dried dispersions with 30% (w/w) naproxen collected from the transport tube of the Pro-C-epT Microspray dryer showed the narrowest glass transition width, which apparently indicates the highest degree of drug-polymer mixing compared to the other locations. The intensity of the naproxen-PVP-VA 64 interaction peak at 1654 cm(-1) of IR spectra differs for solid dispersions (SDs) from the collector and transport tube of Pro-C-epT Microspray dryer with a higher intensity for the latter. Samples with 50% (w/w) naproxen loading collected from the cyclone and the cyclone steel part of the Buchi mini spray dryer showed a melting endotherm (Tm at 112.2 ± 0.8 °C and ΔHf between 0.7 and 1.8 J/g), whereas samples from the cyclone tube to the drying chamber were devoid of crystalline material. The variations in drug-polymer mixing extend to miconazole/PVP-VA solid dispersions where 20% drug loading showed location-dependent drug-polymer mixing. This study clearly showed that the variation in drug-polymer miscibility and solid form of the drug in solid dispersions can occur across spray dryer in small-scale manufacturing processes. The optimization of formulation parameters and spray drying process parameters is imperative to diminish these variations to enhance homogeneity of solid dispersions in laboratory scale spray dryers. The same problem can occur in geometrically large spray drying manufacturing equipment, and the robustness of the processes should be carefully assessed.

  1. Changes in Soil Microbial Community Structure with Flooding

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flooding disturbs both above- and below-ground ecosystem processes. Although often ignored, changes in below-ground environments are no less important than those that occur above-ground. Shifts in soil microbial community structure are expected when anaerobic conditions develop from flooding. The ...

  2. Real Time Monitoring of Flooding from Microwave Satellite Observations

    NASA Technical Reports Server (NTRS)

    Galantowicz, John F.; Frey, H. (Technical Monitor)

    2001-01-01

    In this report, we review the progress to date including results from data analyses and present a schedule of milestones for the remainder of the project. We discuss the processing of flood extent data and SSM/I brightness temperature data for the 1993 Midwest Flood. We present preliminary results from the derivation of open water fraction from brightness temperatures.

  3. The tele-connections of long duration floods and their implications for dynamically updating the Flood Control Pool

    NASA Astrophysics Data System (ADS)

    Devineni, Naresh; Najibi, Nasser; Lall, Upmanu

    2016-04-01

    Traditional approaches to flood risk assessment are typically indexed to an instantaneous peak flow event at a specific recording gage on a river, and then extrapolated through hydraulic modeling of that peak flow to the potential area that is likely to be inundated. However, property losses tend to be determined as much by the duration and volume of flooding as by the depth and velocity of inundation. We argue that the existing notion of a flood risk assessment and consequent reservoir flood control operations needs to be revisited, especially for floods due to persistent rainfall (>30 day duration). Our interest lies in explicitly understanding the dependence of the likelihood or frequency and intensity of extreme regional floods on a causal chain of ocean-atmosphere processes whose slow variation and regime-like changes translate into significant and persistent changes in the probability of major floods in the large river basins. An understanding and mapping of these factors into a dynamic risk framework is important for establishing a process by which flood risk for large basins could be systematically updated reflecting changing climate conditions, whether due to human influence, or as part of the natural cycles of climate variation. In this study, we developed an inference system for climate informed flood risk assessment using an integrated statistical modeling approach. We first develop multivariate flood attributes and classify their characteristic spatial variability using the hierarchical clustering approach. Depending on the flood event type, different rainfall inducing mechanisms (e.g. tropical storm, local convection, frontal system, recurrent tropical waves) may be involved with characteristic spatial scales and statistical properties. Hence, we identify the antecedent rainfall conditions for the flood types and map their corresponding specific atmospheric circulation patterns using compositing of the NCEP/NCAR reanalysis data and the storm tracks

  4. Mitigating flood exposure

    PubMed Central

    Shultz, James M; McLean, Andrew; Herberman Mash, Holly B; Rosen, Alexa; Kelly, Fiona; Solo-Gabriele, Helena M; Youngs Jr, Georgia A; Jensen, Jessica; Bernal, Oscar; Neria, Yuval

    2013-01-01

    Introduction. In 2011, following heavy winter snowfall, two cities bordering two rivers in North Dakota, USA faced major flood threats. Flooding was foreseeable and predictable although the extent of risk was uncertain. One community, Fargo, situated in a shallow river basin, successfully mitigated and prevented flooding. For the other community, Minot, located in a deep river valley, prevention was not possible and downtown businesses and one-quarter of the homes were inundated, in the city’s worst flood on record. We aimed at contrasting the respective hazards, vulnerabilities, stressors, psychological risk factors, psychosocial consequences, and disaster risk reduction strategies under conditions where flood prevention was, and was not, possible. Methods. We applied the “trauma signature analysis” (TSIG) approach to compare the hazard profiles, identify salient disaster stressors, document the key components of disaster risk reduction response, and examine indicators of community resilience. Results. Two demographically-comparable communities, Fargo and Minot, faced challenging river flood threats and exhibited effective coordination across community sectors. We examined the implementation of disaster risk reduction strategies in situations where coordinated citizen action was able to prevent disaster impact (hazard avoidance) compared to the more common scenario when unpreventable disaster strikes, causing destruction, harm, and distress. Across a range of indicators, it is clear that successful mitigation diminishes both physical and psychological impact, thereby reducing the trauma signature of the event. Conclusion. In contrast to experience of historic flooding in Minot, the city of Fargo succeeded in reducing the trauma signature by way of reducing risk through mitigation. PMID:28228985

  5. Achieving Natural Flood Management through collaboration

    NASA Astrophysics Data System (ADS)

    Nicholson, Alex; Byers, Samantha; Thomas, Ted; Welton, Phil

    2016-04-01

    Recent flooding in the UK has brought much attention to the field of Natural flood Management (NFM) as a means of helping to reduce flood risk to communities. Key questions exist in the field, which include quantifying the impact of NFM and maintaining it. In addition, agencies and at-risk communities look for ways of delivering NFM in a tightly stretched financial climate. Well-implemented NFM has the effect of restoring more natural catchment hydrological and sedimentological processes, which in turn can have significant flood risk and WFD benefits for catchment waterbodies. These catchment scale improvements in-turn allow more 'natural' processes to be returned to rivers and streams, creating a more resilient system. NFM can tick many boxes and target many funding opportunities. This paper discusses the NFM component of the Lustrum Beck Flood Alleviation Scheme (Stockton-On-Tees, UK), and explains how a multi-agency approach had to be considered to allow elements of the scheme to be delivered. A startling 70 different landowners and agencies manage the land in the Lustrum Beck catchment (~40km2). A partnership between the Environment Agency and the Forestry Commission is planning to work on a demonstration site in the centre of the catchment. The paper goes on to explain the importance of this demonstration area in the context of the wider scheme.

  6. Crowdsourcing detailed flood data

    NASA Astrophysics Data System (ADS)

    Walliman, Nicholas; Ogden, Ray; Amouzad*, Shahrzhad

    2015-04-01

    Over the last decade the average annual loss across the European Union due to flooding has been 4.5bn Euros, but increasingly intense rainfall, as well as population growth, urbanisation and the rising costs of asset replacements, may see this rise to 23bn Euros a year by 2050. Equally disturbing are the profound social costs to individuals, families and communities which in addition to loss of lives include: loss of livelihoods, decreased purchasing and production power, relocation and migration, adverse psychosocial effects, and hindrance of economic growth and development. Flood prediction, management and defence strategies rely on the availability of accurate information and flood modelling. Whilst automated data gathering (by measurement and satellite) of the extent of flooding is already advanced it is least reliable in urban and physically complex geographies where often the need for precise estimation is most acute. Crowdsourced data of actual flood events is a potentially critical component of this allowing improved accuracy in situations and identifying the effects of local landscape and topography where the height of a simple kerb, or discontinuity in a boundary wall can have profound importance. Mobile 'App' based data acquisition using crowdsourcing in critical areas can combine camera records with GPS positional data and time, as well as descriptive data relating to the event. This will automatically produce a dataset, managed in ArcView GIS, with the potential for follow up calls to get more information through structured scripts for each strand. Through this local residents can provide highly detailed information that can be reflected in sophisticated flood protection models and be core to framing urban resilience strategies and optimising the effectiveness of investment. This paper will describe this pioneering approach that will develop flood event data in support of systems that will advance existing approaches such as developed in the in the UK

  7. A laboratory investigation of the optimum CO/sub 2/ slug size required for CO/sub 2/ flooding

    SciTech Connect

    Omole, O.; Osoba, J.S.

    1984-02-01

    The optimum CO/sub 2/ bank size required during CO/sub 2/ flooding was studied in linear horizontal consolidated sandstone cores. Crude oils were displaced from the cores by different CO/sub 2/ slug sizes propelled with brine at pressures above the CO/sub 2/ - crude oil miscibility pressures of the oils. Two natural crude oils of 34/sup 0/ and 44/sup 0/ API gravity, two 2 in. X 2 in. 15 foot long and a 5 foot long horizontal consolidated sandstone cores were used for the investigation. Studies were conducted at 110/sup 0/ and at 120/sup 0/ F. A 0.3 HPV of CO/sub 2/ slug was found to be an optimum bank size required for flooding in the horizontal cores using water as the slug propellant. The total oil recoveries were lower for tests conducted at 120/sup 0/ F than for those conducted at 110/sup 0/ F.

  8. Floods in Colorado

    USGS Publications Warehouse

    Follansbee, Robert; Sawyer, Leon R.

    1948-01-01

    The first records of floods in Colorado antedated the settlement of the State by about 30 years. These were records of floods on the Arkansas and Republican Rivers in 1826. Other floods noted by traders, hunters and emigrants, some of whom were on their way to the Far West, occurred in 1844 on the Arkansas River, and by inference on the South Platte River. Other early floods were those on the Purgatoire, the Lower Arkansas, and the San Juan Rivers about 1859. The most serious flood since settlement began was that on the Arkansas River during June 1921, which caused the loss of about 100 lives and an estimated property loss of $19,000,000. Many floods of lesser magnitude have occurred, and some of these have caused loss of life and very considerable property damage. Topography is the chief factor in determining the location of storms and resulting floods. These occur most frequently on the eastern slope of the Front Range. In the mountains farther west precipitation is insufficient to cause floods except during periods of melting snow, in June. In the southwestern part of the State, where precipitation during periods of melting snow is insufficient to cause floods, the severest floods yet experienced resulted from heavy rains in September 1909 and October 1911. In the eastern foothills region, usually below an altitude of about 7,500 feet and extending for a distance of about 50 miles east of the mountains, is a zone subject to rainfalls of great intensity known as cloudbursts. These cloudbursts are of short duration and are confined to very small areas. At times the intensity is so great as to make breathing difficult for those exposed to a storm. The areas of intense rainfall are so small that Weather Bureau precipitation stations have not been located in them. Local residents, being cloudburst conscious, frequently measure the rainfall in receptacles in their yards, and such records constitute the only source of information regarding the intensity. A flood

  9. The variation characteristics analysis of polymer concentration in polymer flooding

    NASA Astrophysics Data System (ADS)

    Li, Kai

    2017-03-01

    Since the polymer industry promotion block production, with the development of polymer flooding from the main oil layer to the second type of oil gradually expanded, polymer flooding the whole process of the development of the law is also gradually deepening, gathering concentration is the analysis of polymer. The results show that there is a certain variation rule of the concentration of polymer in the whole process of polymer flooding development through the accumulation of a large number of gathering concentration data. In this paper, the characteristics of polymer flooding concentration, comprehensive water cut down rate, comprehensive water cut down, water cutoff duration and subsequent water flooding concentration and comprehensive water content are expounded, as well as the influence of polymer concentration and the changing trend of the concentration of polymer flooding in the development process was analyzed. In-depth study and grasp the concentration of mining concentration, can further improve the overall effect of polymer flooding development, but also for the follow-up injection block, especially the second type of polymer flooding development has great significance.

  10. Development of an Advanced Simulator to Model Mobility Control and Geomechanics during CO{sub 2} Floods

    SciTech Connect

    Delshad, Mojdeh; Wheeler, Mary; Sepehrnoori, Kamy; Pope, Gary

    2013-12-31

    The simulator is an isothermal, three-dimensional, four-phase, compositional, equation-of– state (EOS) simulator. We have named the simulator UTDOE-CO2 capable of simulating various recovery processes (i.e., primary, secondary waterflooding, and miscible and immiscible gas flooding). We include both the Peng-Robinson EOS and the Redlich-Kwong EOS models. A Gibbs stability test is also included in the model to perform a phase identification test to consistently label each phase for subsequent property calculations such as relative permeability, viscosity, density, interfacial tension, and capillary pressure. Our time step strategy is based on an IMPEC-type method (implicit pressure and explicit concentration). The gridblock pressure is solved first using the explicit dating of saturation-dependent terms. Subsequently, the material balance equations are solved explicitly for the total concentration of each component. The physical dispersion term is also included in the governing equations. The simulator includes (1) several foam model(s) for gas mobility control, (2) compositional relative permeability models with the hysteresis option, (3) corner point grid and several efficient solvers, (4) geomechanics module to compute stress field as the result of CO{sub 2} injection/production, (5) the format of commercial visualization software, S3graf from Science-soft Ltd., was implemented for user friendly visualization of the simulation results. All tasks are completed and the simulator was fully tested and delivered to the DOE office including a user’s guide and several input files and the executable for Windows Pcs. We have published several SPE papers, presented several posters, and one MS thesis is completed (V. Pudugramam, 2013) resulting from this DOE funded project.

  11. 77 FR 18842 - Proposed Flood Hazard Determinations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-28

    ... SECURITY Federal Emergency Management Agency Proposed Flood Hazard Determinations AGENCY: Federal Emergency Management Agency, DHS. ACTION: Notice. SUMMARY: Comments are requested on proposed flood hazard determinations, which may include additions or modifications of any Base Flood Elevation (BFE), base flood...

  12. 78 FR 5824 - Proposed Flood Hazard Determinations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-28

    ... SECURITY Federal Emergency Management Agency Proposed Flood Hazard Determinations AGENCY: Federal Emergency Management Agency, DHS. ACTION: Notice. SUMMARY: Comments are requested on proposed flood hazard determinations, which may include additions or modifications of any Base Flood Elevation (BFE), base flood...

  13. 77 FR 18846 - Proposed Flood Hazard Determinations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-28

    ... SECURITY Federal Emergency Management Agency Proposed Flood Hazard Determinations AGENCY: Federal Emergency Management Agency, DHS. ACTION: Notice. SUMMARY: Comments are requested on proposed flood hazard determinations, which may include additions or modifications of any Base Flood Elevation (BFE), base flood...

  14. 78 FR 21143 - Proposed Flood Hazard Determinations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-09

    ... SECURITY Federal Emergency Management Agency Proposed Flood Hazard Determinations AGENCY: Federal Emergency Management Agency, DHS. ACTION: Notice. SUMMARY: Comments are requested on proposed flood hazard determinations, which may include additions or modifications of any Base Flood Elevation (BFE), base flood...

  15. 77 FR 18839 - Proposed Flood Hazard Determinations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-28

    ... SECURITY Federal Emergency Management Agency Proposed Flood Hazard Determinations AGENCY: Federal Emergency Management Agency, DHS. ACTION: Notice. SUMMARY: Comments are requested on proposed flood hazard determinations, which may include additions or modifications of any Base Flood Elevation (BFE), base flood...

  16. 77 FR 18844 - Proposed Flood Hazard Determinations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-28

    ... SECURITY Federal Emergency Management Agency Proposed Flood Hazard Determinations AGENCY: Federal Emergency Management Agency, DHS. ACTION: Notice. SUMMARY: Comments are requested on proposed flood hazard determinations, which may include additions or modifications of any Base Flood Elevation (BFE), base flood...

  17. 78 FR 48701 - Proposed Flood Hazard Determinations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-09

    ... SECURITY Federal Emergency Management Agency Proposed Flood Hazard Determinations AGENCY: Federal Emergency Management Agency, DHS. ACTION: Notice. SUMMARY: Comments are requested on proposed flood hazard determinations, which may include additions or modifications of any Base Flood Elevation (BFE), base flood...

  18. 77 FR 18835 - Proposed Flood Hazard Determinations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-28

    ... SECURITY Federal Emergency Management Agency Proposed Flood Hazard Determinations AGENCY: Federal Emergency Management Agency, DHS. ACTION: Notice. SUMMARY: Comments are requested on proposed flood hazard determinations, which may include additions or modifications of any Base Flood Elevation (BFE), base flood...

  19. 78 FR 5822 - Proposed Flood Hazard Determinations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-28

    ... SECURITY Federal Emergency Management Agency Proposed Flood Hazard Determinations AGENCY: Federal Emergency Management Agency, DHS. ACTION: Notice. SUMMARY: Comments are requested on proposed flood hazard determinations, which may include additions or modifications of any Base Flood Elevation (BFE), base flood...

  20. 77 FR 74859 - Proposed Flood Hazard Determinations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-18

    ... SECURITY Federal Emergency Management Agency Proposed Flood Hazard Determinations AGENCY: Federal Emergency Management Agency, DHS. ACTION: Notice. SUMMARY: Comments are requested on proposed flood hazard determinations, which may include additions or modifications of any Base Flood Elevation (BFE), base flood...

  1. 78 FR 5826 - Proposed Flood Hazard Determinations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-28

    ... SECURITY Federal Emergency Management Agency Proposed Flood Hazard Determinations AGENCY: Federal Emergency Management Agency, DHS. ACTION: Notice. SUMMARY: Comments are requested on proposed flood hazard determinations, which may include additions or modifications of any Base Flood Elevation (BFE), base flood...

  2. 78 FR 49277 - Proposed Flood Hazard Determinations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-13

    ... SECURITY Federal Emergency Management Agency Proposed Flood Hazard Determinations AGENCY: Federal Emergency Management Agency, DHS. ACTION: Notice. SUMMARY: Comments are requested on proposed flood hazard determinations, which may include additions or modifications of any Base Flood Elevation (BFE), base flood...

  3. 78 FR 49278 - Proposed Flood Hazard Determinations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-13

    ... SECURITY Federal Emergency Management Agency Proposed Flood Hazard Determinations AGENCY: Federal Emergency Management Agency, DHS. ACTION: Notice. SUMMARY: Comments are requested on proposed flood hazard determinations, which may include additions or modifications of any Base Flood Elevation (BFE), base flood...

  4. 77 FR 18841 - Proposed Flood Hazard Determinations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-28

    ... SECURITY Federal Emergency Management Agency Proposed Flood Hazard Determinations AGENCY: Federal Emergency Management Agency, DHS. ACTION: Notice. SUMMARY: Comments are requested on proposed flood hazard determinations, which may include additions or modifications of any Base Flood Elevation (BFE), base flood...

  5. Union soluble oil flood in El Dorado cores

    SciTech Connect

    Chiou, C.S.

    1983-02-01

    Results are presented of laboratory experiments using Union's soluble oil flood process in El Dorado cores. The core flood is to provide complete information on fluid compositions and phase behavior of the effluents such that adequate core flood match using the chemical flood simulator can be made. This step is essential for evaluating reservoir performance on the South Pattern of the El Dorado Micellar-Polymer Project. The results show the caustic preflush in the flood process causes face plugging of the field cores. The problem was controlled by using chelating agents along with the caustic fluid to keep divalent cations in solution. The required amount of chelating agent was determined to be ca 25 times as strong as the original design for the field test. Liquid chromatography analysis of sulfonate provides valuable information on selective fractionation of monosulfonate in the micellar fluid. 10 references.

  6. The Global Flood Model

    NASA Astrophysics Data System (ADS)

    Williams, P.; Huddelston, M.; Michel, G.; Thompson, S.; Heynert, K.; Pickering, C.; Abbott Donnelly, I.; Fewtrell, T.; Galy, H.; Sperna Weiland, F.; Winsemius, H.; Weerts, A.; Nixon, S.; Davies, P.; Schiferli, D.

    2012-04-01

    Recently, a Global Flood Model (GFM) initiative has been proposed by Willis, UK Met Office, Esri, Deltares and IBM. The idea is to create a global community platform that enables better understanding of the complexities of flood risk assessment to better support the decisions, education and communication needed to mitigate flood risk. The GFM will provide tools for assessing the risk of floods, for devising mitigation strategies such as land-use changes and infrastructure improvements, and for enabling effective pre- and post-flood event response. The GFM combines humanitarian and commercial motives. It will benefit: - The public, seeking to preserve personal safety and property; - State and local governments, seeking to safeguard economic activity, and improve resilience; - NGOs, similarly seeking to respond proactively to flood events; - The insurance sector, seeking to understand and price flood risk; - Large corporations, seeking to protect global operations and supply chains. The GFM is an integrated and transparent set of modules, each composed of models and data. For each module, there are two core elements: a live "reference version" (a worked example) and a framework of specifications, which will allow development of alternative versions. In the future, users will be able to work with the reference version or substitute their own models and data. If these meet the specification for the relevant module, they will interoperate with the rest of the GFM. Some "crowd-sourced" modules could even be accredited and published to the wider GFM community. Our intent is to build on existing public, private and academic work, improve local adoption, and stimulate the development of multiple - but compatible - alternatives, so strengthening mankind's ability to manage flood impacts. The GFM is being developed and managed by a non-profit organization created for the purpose. The business model will be inspired from open source software (eg Linux): - for non-profit usage

  7. Assessing the Strength Enhancement of Heterogeneous Networks of Miscible Blends of 1,2-Polybutadiene and Polyisoprene

    NASA Astrophysics Data System (ADS)

    Giller, Carl; Roland, Mike

    2012-02-01

    At typical crosslink densities of elastomers, 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, so that the chemical composition is uniform on the nm 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 vulcanized blends of 1,2-polybutadiene and polyisoprene, taking advantage of their differing reactivities to sulfur. In this work we explore networks of this miscible blend formed via UV irradiation with a photoinitiator. The vinyl group in 1,2-polybutadiene has a much greater photo-reactivity than the double bond in polyisoprene, resulting in a disparity in respective degrees of crosslinking, while the thermodynamic miscibility is retained. Mechanical properties of the radiation crosslinked blend are compared to conventional networks.

  8. Investigation and correlation of drug polymer miscibility and molecular interactions by various approaches for the preparation of amorphous solid dispersions.

    PubMed

    Meng, Fan; Trivino, Anne; Prasad, Dev; Chauhan, Harsh

    2015-04-25

    Curcumin (CUR) was used as a poorly soluble drug whereas polyvinyl pyrrolidone K90 (PVP), Eudragit EPO (EPO), hydroxypropyl methylcellulose E5 (HPMC) and polyethylene glycol 8000 (PEG) were used as hydrophilic polymers. CUR polymer miscibility was evaluated by solubility parameter, melting point depression and glass transition temperature (Tg) measurements. Molecular interactions between CUR and polymers were determined by Fourier-transform infrared spectroscopy (FTIR) and Raman. Amorphous solid dispersions were prepared with CUR-polymer ratio of 70:30 (w/w) by solvent evaporation technique and were evaluated for dissolution enhancement using USP II method. Physical states of solid dispersions were characterized by X-ray diffraction (XRD) whereas thermal behaviors were investigated using modulated differential scanning calorimetry (MDSC). CUR-EPO system showed good miscibility through all the approaches, whereas immiscibility was found in other CUR-polymer systems. CUR-EPO and CUR-HPMC systems showed significant molecular interactions whereas CUR-PVP and CUR-PEG showed no molecular interactions. All solid dispersions showed significant dissolution enhancement with CUR-EPO showing highest dissolution rate during first 1h whereas CUR-HPMC was effective in maintaining high CUR concentrations for 6h. The study highlights the importance of investigating and correlating drug polymer miscibility and molecular interactions by various approaches for successful formulation of amorphous solid dispersions.

  9. Sustainability appraisal and flood risk management

    SciTech Connect

    Carter, Jeremy G. White, Iain Richards, Juliet

    2009-01-15

    This research establishes that sustainability appraisal (SA) has a role to play in strengthening spatial plans in the context of flooding issues. Indeed, evidence has been gathered to indicate that tentative steps are being taken in this direction during the SA of English regional spatial plans, which are used as an illustrative case study. In England as in many other countries, appraisal procedures including SA and strategic environmental assessment (SEA) are enshrined in planning law. An opportunity therefore exists to utilise existing and familiar planning tools to embed flooding considerations within spatial plans at an early stage in the planning process. SA (and similar appraisal tools such as SEA) can therefore usefully aid in the implementation of decision making principles and government policy relating to flooding. Moreover, with the threats associated with climate change becoming increasingly apparent, of which increased flood risk is a particular concern in many countries, there is a need develop appropriate adaptation responses. This article emphasizes the role that SA can play in managing future flood risk in this context.

  10. The pattern of spatial flood disaster region in DKI Jakarta

    NASA Astrophysics Data System (ADS)

    Tambunan, M. P.

    2017-02-01

    The study of disaster flood area was conducted in DKI Jakarta Province, Indonesia. The aim of this research is: to study the spatial distribution of potential and actual of flood area The flood was studied from the geographic point of view using spatial approach, while the study of the location, the distribution, the depth and the duration of flooding was conducted using geomorphologic approach and emphasize on the detailed landform unit as analysis unit. In this study the landforms in DKI Jakarta have been a diversity, as well as spatial and temporal pattern of the actual and potential flood area. Landform at DKI Jakarta has been largely used as built up area for settlement and it facilities, thus affecting the distribution pattern of flooding area. The collection of the physical condition of landform in DKI Jakarta data prone were conducted through interpretation of the topographic map / RBI map and geological map. The flood data were obtained by survey and secondary data from Kimpraswil (Public Work) of DKI Jakarta Province for 3 years (1996, 2002, and 2007). Data of rainfall were obtained from BMKG and land use data were obtained from BPN DKI Jakarta. The analysis of the causal factors and distribution of flooding was made spatially and temporally using geographic information system. This study used survey method with a pragmatic approach. In this study landform as result from the analytical survey was settlement land use as result the synthetic survey. The primary data consist of landform, and the flood characteristic obtained by survey. The samples were using purposive sampling. Landform map was composed by relief, structure and material stone, and process data Landform map was overlay with flood map the flood prone area in DKI Jakarta Province in scale 1:50,000 to show. Descriptive analysis was used the spatial distribute of the flood prone area. The result of the study show that actual of flood prone area in the north, west and east of Jakarta lowland both

  11. Flood Heterogeneity as a Tool for Exploring Flood Frequency-Climate Linkages from a Watershed Perspective

    NASA Astrophysics Data System (ADS)

    Zamora-Reyes, D.; Hirschboeck, K. K.; Valdes, J. B.

    2013-12-01

    Accurate discharge estimates derived from flood frequency analysis (FFA) are needed for real-world applications to reduce or eliminate flood hazard impacts. In the US, these estimates are currently calculated following the FFA method described in the 1982 Bulletin 17b (B17b) of the Hydrology Subcommittee of the Interagency Advisory Committee on Water Data. Although it has proven to be efficient over the past 30 years, the authors and the hydrologic community agree that it's time for an update. An assumption made in B17b is that all floods come from the same homogeneous population when in reality heterogeneity may exist. For such cases, incorporation of the driving atmospheric mechanisms into the analysis is encouraged even if it becomes a statistically challenging problem. Moreover, watersheds that currently exhibit heterogeneity can benefit from this alternative analysis since climate change might not affect the prevalence of all flood types similarly. Arizona's geographic location and complex terrain are associated with three different types of flood-generating atmospheric processes: summer convective thunderstorms, tropical cyclone-enhanced convective activity, and winter synoptic-scale storms. In an earlier study, regional patterns of flood heterogeneity in Arizona were found to influence flood frequency discharge estimates in individual watersheds. In this study we build on these watershed-based climate-flood linkages by exploring the temporal relationship between flood heterogeneity and climatic variability. US Geological Survey partial duration series (PDS) peak flow discharge records from stations across Arizona were compiled and classified according to meteorological cause. Subsequently, the PDS for each station was analyzed for the prevalence of each flood type by counting the number of peaks-over-threshold in each classification per water year. The observed record revealed distinct periods of temporal dominance by different flood producing mechanisms, e

  12. Multivariate pluvial flood damage models

    SciTech Connect

    Van Ootegem, Luc; Verhofstadt, Elsy; Van Herck, Kristine; Creten, Tom

    2015-09-15

    Depth–damage-functions, relating the monetary flood damage to the depth of the inundation, are commonly used in the case of fluvial floods (floods caused by a river overflowing). We construct four multivariate damage models for pluvial floods (caused by extreme rainfall) by differentiating on the one hand between ground floor floods and basement floods and on the other hand between damage to residential buildings and damage to housing contents. We do not only take into account the effect of flood-depth on damage, but also incorporate the effects of non-hazard indicators (building characteristics, behavioural indicators and socio-economic variables). By using a Tobit-estimation technique on identified victims of pluvial floods in Flanders (Belgium), we take into account the effect of cases of reported zero damage. Our results show that the flood depth is an important predictor of damage, but with a diverging impact between ground floor floods and basement floods. Also non-hazard indicators are important. For example being aware of the risk just before the water enters the building reduces content damage considerably, underlining the importance of warning systems and policy in this case of pluvial floods. - Highlights: • Prediction of damage of pluvial floods using also non-hazard information • We include ‘no damage cases’ using a Tobit model. • The damage of flood depth is stronger for ground floor than for basement floods. • Non-hazard indicators are especially important for content damage. • Potential gain of policies that increase awareness of flood risks.

  13. Epic Flooding in Georgia, 2009

    USGS Publications Warehouse

    Gotvald, Anthony J.; McCallum, Brian E.

    2010-01-01

    Metropolitan Atlanta-September 2009 Floods The epic floods experienced in the Atlanta area in September 2009 were extremely rare. Eighteen streamgages in the Metropolitan Atlanta area had flood magnitudes much greater than the estimated 0.2-percent (500-year) annual exceedance probability. The Federal Emergency Management Agency (FEMA) reported that 23 counties in Georgia were declared disaster areas due to this flood and that 16,981 homes and 3,482 businesses were affected by floodwaters. Ten lives were lost in the flood. The total estimated damages exceed $193 million (H.E. Longenecker, Federal Emergency Management Agency, written commun., November 2009). On Sweetwater Creek near Austell, Ga., just north of Interstate 20, the peak stage was more than 6 feet higher than the estimated peak stage of the 0.2-percent (500-year) flood. Flood magnitudes in Cobb County on Sweetwater, Butler, and Powder Springs Creeks greatly exceeded the estimated 0.2-percent (500-year) floods for these streams. In Douglas County, the Dog River at Ga. Highway 5 near Fairplay had a peak stage nearly 20 feet higher than the estimated peak stage of the 0.2-percent (500-year) flood. On the Chattahoochee River, the U.S. Geological Survey (USGS) gage at Vinings reached the highest level recorded in the past 81 years. Gwinnett, De Kalb, Fulton, and Rockdale Counties also had record flooding.South Georgia March and April 2009 FloodsThe March and April 2009 floods in South Georgia were smaller in magnitude than the September floods but still caused significant damage. No lives were lost in this flood. Approximately $60 million in public infrastructure damage occurred to roads, culverts, bridges and a water treatment facility (Joseph T. McKinney, Federal Emergency Management Agency, written commun., July 2009). Flow at the Satilla River near Waycross, exceeded the 0.5-percent (200-year) flood. Flows at seven other stations in South Georgia exceeded the 1-percent (100-year) flood.

  14. Mental models of flash floods and landslides.

    PubMed

    Wagner, Klaus

    2007-06-01

    Perceptions of flash floods and landslides were analyzed in four communities of the Bavarian Alps using the mental model approach. Thirty-eight qualitative interviews, two telephone surveys with 600 respondents, and two onsite interviews (74/95 respondents) were conducted. Mental models concerning flash floods are much better developed than those for landslides because the key physical processes for flash floods are easier for the general public to recognize and understand. Mental models are influenced by the local conditions. People who have a better knowledge about the hazards are those who use many different sources to inform themselves, express fear about natural hazards, or have previous experience with hazards. Conclusions for how to improve information for the general public are discussed.

  15. Climate change impacts on flood seasonality in Norway

    NASA Astrophysics Data System (ADS)

    Vormoor, Klaus; Heistermann, Maik; Lawrence, Deborah; Bronstert, Axel

    2013-04-01

    The hydrological impacts of climate change on floods have been studied by ensemble based modeling in 115 catchments in Norway (Lawrence & Hisdal 2011). Despite of a considerable variation in the projections, consistent regional patterns of hydrological change are evident. Spatial patterns of directional change in flood magnitude allow for drawing conclusions about dominating flood-generating processes and for differentiating regions with similar flood regimes. Since the magnitude of floods results from the seasonality of precipitation, snowmelt/snow storage, and the preconditions in a catchment, seasonal flood frequency analysis can help to understand the influence of flood-generating processes under a changing climate. Currently, regional patterns of flood regimes in Norway separate regions which are dominated by high flows during the spring and early summer snowmelt season (inland and northernmost regions) from regions where autumn and winter pluvial floods are dominant (western Norway along the coast). However, projected increase in winter temperature, reduced snow storage and earlier snowmelt will probably lead to a reduction in flood probability in inland and northern Norway. In western Norway and along the coast, the probability of large floods is likely to increase due to projected increases in seasonal and extreme rainfall. In addition, there are some areas which probably will be dominated by a mixed regime in the future where both snowmelt- and rainfall-dominated events will occur. Based on an ensemble model approach in a subset of representative catchments, we study the role of seasonality contributing to flood hazards in Norway. Seasonal flood frequency analyses are used to explore changes in flood seasonality. Peak flow series are analyzed using a Peak Over Threshold (POT) approach, and changes in the return periods are estimated based on the Generalized Pareto Distribution (GPD). A model re-calibration is performed based on the series distance approach

  16. Effects of G-Jitter on Interfacial Dynamics of Two Miscible Liquids: Application of MIM

    NASA Technical Reports Server (NTRS)

    Duval, Walter M. B.; Tryggvason, Bjarni V.

    2000-01-01

    We designed an experiment to examine the effects of g-jitter on mixing of two miscible liquids using the Microgravity Vibration Isolation Mount (MIM). The global bifurcation of the interface was observed with the MIM operating alternatively to either transmit the g-jitter, isolate from the g-jitter or to provide controlled vibration levels with well defined amplitude and frequency content. With the MIM in isolation mode, the interface remains stationary indicating buoyancy induced convection is negligibly small such that mixing occurs via intrinsic mass diffusion without the masking effect of vibration driven convection. Analytical and computational results are in agreement with the experimental findings. Operation of the MIM in forced mode with conditions typical of g-jitter shows that vibration induced convective flows can excite instability mechanisms such as Kelvin-Helmholtz to generate large amplitude quasi-stationary waves oriented vertically for various cases with Stokes-Reynolds number in the range of 0.003 to 0.5. The two and four mode quasi-stationary waves are also predicted with a mathematical model. Though unplanned, the effect of a primary thruster filing was captured and shown to cause a catastrophic bifurcation, enhancing local mass transport. In light of the findings, experiments planned for the International Space Station should consider the potential effects of g-jitter.

  17. Ag-Pt alloy nanoparticles with the compositions in the miscibility gap

    SciTech Connect

    Peng Zhenmeng; Yang Hong

    2008-07-15

    Silver platinum binary alloys with compositions between about Ag{sub 2}Pt{sub 98} and Ag{sub 95}Pt{sub 5} at <{approx} 400 deg. C have largely not been observed in bulk due to the large immiscibility between these two metals. We present in this paper that Ag-Pt alloy nanostructures can be made in a broad composition range. The formation of Ag-Pt nanostructures is studied by powder X-ray diffraction (PXRD) and energy-dispersive X-ray (EDX). Our results indicate that lattice parameter changes almost linearly with composition in these Ag-Pt nanomaterials. In another word, lattice parameter and composition relationship follows the Vegard's law, which is a strong indication for the formation of metal alloys. Our transmission electron microscopy (TEM) study shows that the silver-rich Ag-Pt alloy nanostructures have spherical shape, while the platinum-rich ones possess wire-like morphology. The stability and crystal phase are investigated by annealing the alloy nanostructures directly or on carbon supports. - Graphical abstract: While platinum and silver cannot form a solid solution with the composition between about Ag{sub 2}Pt{sub 98} and Ag{sub 95}Pt{sub 5} at 400 deg. C or below in bulk form, alloy particles and wires can be made within this miscibility gap at the nanometer scale.

  18. Miscibility of Hydrocarbon and Fluorocarbon Surfactants in Adsorbed Film and Micelle.

    PubMed

    Villeneuve, Masumi; Nomura, Teruko; Matsuki, Hitoshi; Kaneshina, Shoji; Aratono, Makoto

    2001-02-01

    We investigated the miscibility of nonionic hydrocarbon and fluorocarbon surfactants in the adsorbed film and the micelle by surface tension measurements of the aqueous solution. The combination of tetraethyleneglycol monodecyl ether (C10E4) and tetraethyleneglycol mono-1,1,7-trihydrododecafluoroheptyl ether (FC7E4) was chosen because they have the same hydrophilic groups and about the same surface activity. The extent of nonideal mixing was estimated quantitatively in terms of the excess Gibbs energy in the adsorbed film g(H,E) and that in the micelle g(M,E). The excess area per adsorbed molecule, A(H,E), was also evaluated and discussed. The ionic hydrocarbon and fluorocarbon mixed surfactant systems, lithium dodecyl sulfate (LiDS)/lithium perfluorooctane sulfonate (LiFOS) and lithium tetradecyl sulfate (LiTS)/LiFOS systems are also investigated from the standpoint of excess Gibbs energy and excess area. It is also clearly shown that the regular solution approach does not fit in the systems that contain ionic species. Copyright 2001 Academic Press.

  19. Self-assembly of Iron Oxide Nanoparticles on Liquid Surfaces by Using Miscible Solvent Pairs

    NASA Astrophysics Data System (ADS)

    Hu, Jiayang; Zhang, Datong; Kennedy, Kathleen M.; Herman, Irving P.

    Nanoparticle (NP) self-assembly on liquid-air interfaces by using immiscible solvent pairs is a fast and effective way to prepare two-dimensional (2D) close-packed superlattices. However, this technique is limited by the number of available solvent pairs that are immiscible with each other while being different in the dispersity of NPs. Here, we report forming 2D superlattices using toluene/dimethyl sulfoxide miscible solvent pairs. In-situ small angle X-ray scattering patterns from NP layers sitting on the meniscus agree with patterns expected from 2D tilted closed packed superlattices. Real time optical microscopy shows that after drop casting, most of NPs coagulate immediately and sink to the bottom over several days, but leave a continuous ML on the surface, without forming 3D clusters that are usually seen in the immiscible techniques generated by the ``coffee ring'' effect. TEM images show that NPs nucleate simultaneously on different parts on the liquid surface until they touch, therefore covering the whole surface.

  20. Growth dynamics of isotactic polypropylene single crystals during isothermal crystallization from a miscible polymeric solvent.

    PubMed

    Mehta, Rujul; Keawwattana, Wirunya; Kyu, Thein

    2004-02-22

    The present article presents a spatiotemporal growth of isotactic polypropylene (iPP) single crystals, melt crystallized from a polymeric solvent, i.e., poly (ethylene octene) copolymer that is known to be miscible with iPP. Optical and atomic force microscopic investigations reveal that the melt grown single crystals of iPP develop in the form of two parallel rows of crystal lamellae, but these crystals merge at the tips. To elucidate the mechanism of these emerging parallel rows of iPP crystals, a phase field model pertaining to solidification phenomena has been employed that involves a nonconserved crystal order parameter and a chain-tilting angle. This phase field model is based on the free energy of crystallization, having an asymmetric double well, and a tensorial surface free energy of the crystal interface coupled with a curvature elastic free energy that is possessed by the solid-liquid interface. The spatiotemporal simulation of iPP single crystal growth has been carried out on a square lattice based on the finite difference method for spatial steps and an explicit method for temporal steps with a periodic boundary condition. The appearance of the seemingly twin crystal is captured in the simulation, which may be attributed to the sector demarcation that is taking place in the anisotropically growing single crystal of iPP.

  1. Growth dynamics of isotactic polypropylene single crystals during isothermal crystallization from a miscible polymeric solvent

    NASA Astrophysics Data System (ADS)

    Mehta, Rujul; Keawwattana, Wirunya; Kyu, Thein

    2004-02-01

    The present article presents a spatiotemporal growth of isotactic polypropylene (iPP) single crystals, melt crystallized from a polymeric solvent, i.e., poly (ethylene octene) copolymer that is known to be miscible with iPP. Optical and atomic force microscopic investigations reveal that the melt grown single crystals of iPP develop in the form of two parallel rows of crystal lamellae, but these crystals merge at the tips. To elucidate the mechanism of these emerging parallel rows of iPP crystals, a phase field model pertaining to solidification phenomena has been employed that involves a nonconserved crystal order parameter and a chain-tilting angle. This phase field model is based on the free energy of crystallization, having an asymmetric double well, and a tensorial surface free energy of the crystal interface coupled with a curvature elastic free energy that is possessed by the solid-liquid interface. The spatiotemporal simulation of iPP single crystal growth has been carried out on a square lattice based on the finite difference method for spatial steps and an explicit method for temporal steps with a periodic boundary condition. The appearance of the seemingly twin crystal is captured in the simulation, which may be attributed to the sector demarcation that is taking place in the anisotropically growing single crystal of iPP.

  2. Spreading and mixing of drops on a miscible liquid of different surface tension

    NASA Astrophysics Data System (ADS)

    Afkhami, S.; Seric, I.; Kondic, L.; Kim, H.; Shardt, O.; Stone, H. A.

    2016-11-01

    We carry out Volume-of-Fluid based numerical simulations of a Marangoni-driven spreading of isopropyl alcohol (IPA) drops placed on water-air interface. The two fully miscible liquids create a spatially varying surface tension, leading to the spreading of the IPA drop on the water surface. We study the spreading of drops as IPA concentration is varied. In particular, we compute the spreading velocity and show that the scaling of the front position, L, with time, t, is given by L t 0 . 7 . We observe that while the surface tension difference between the two liquids controls the spreading velocity, it only slightly alters the power-law behavior for the range of considered IPA concentrations. We also provide detailed insight of the mixing of the IPA and water, and show the time evolution of liquid-air surface tension distribution. We show that the mixing results in a volume flux in a thin region on the surface, generating a vortical flow underneath the spreading front; we investigate the details of these flow patterns and show the time evolution of the circulation within the water. The numerical results are supported by new experimental observations reported separately.

  3. Experimental study of miscible displacement fronts in rough self-affine fractures

    SciTech Connect

    Auradou, Harold; Hulin, Jean-Pierre; Roux, Stephane

    2001-06-01

    Miscible fluid displacements are studied experimentally in a radial flow between two complementary replica of a self-affine rough granite fracture surface. The displacement front between a dyed fluid and a transparent (but otherwise identical) one is followed optically through one face of the cell. The evolution of its geometry is studied as a function of time, flow-rate, and normal and lateral relative displacements between the two surfaces. For a purely normal displacement, the front is globally smooth, due to the constant local distance between surfaces. For a finite lateral displacement, the front is rough due to spatial variations of this distance; its geometry is fractal and its dimension is directly related to the Hurst exponent H{approximately}0.8 of the surface. The fractal regime is observed only above a lower cut-off scale that depends on the normal spacing of the surfaces and an upper one that increases with the injected volume and with the amplitude of the lateral displacement.

  4. Characteristics of proportionate growth observed in instability patterns of miscible fluids

    NASA Astrophysics Data System (ADS)

    Bischofberger, Irmgard; Ramachandran, Radha; Nagel, Sidney R.; Nagel lab Team

    2014-11-01

    As a baby mammal grows, different parts of its body develop at the nearly the same rate and thus to a good approximation in direct proportion to one another. This type of growth is called proportionate growth. As familiar as it appears to us, it is very rarely found in physical systems outside of the biological world. We here show an example of proportionate growth that occurs in the instability formed when a less viscous liquid, of viscosity ηin displaces a more viscous miscible one, of viscosity ηout. We investigate the growth of these patterns in a quasi-two-dimensional geometry. Within a range of viscosity ratios 0.1 <ηin /ηout <0.3, we observe the formation of small blunt structures that form at the edges of an inner circular region devoid of fingers. As the pattern grows, the size of these structures increases in proportion to the size of the inner circle, such that even small details in the shape of the pattern remain essentially unchanged during growth. These characteristics of proportionate growth are reflected in the shape of the interface in the third dimension as well.

  5. Three-dimensional miscible displacement simulations in homogeneous porous media with gravity override

    NASA Astrophysics Data System (ADS)

    Riaz, A.; Meiburg, E.

    2003-11-01

    High-accuracy three-dimensional numerical simulations of miscible displacements with gravity override in homogeneous porous media are carried out for the quarter five-spot configuration. Special emphasis is placed on describing the influence of viscous and gravitational effects on the overall displacement dynamics in terms of the vorticity variable. Even for neutrally buoyant displacements, three-dimensional effects are seen to change the character of the flow significantly, in contrast to earlier findings for rectilinear displacements. At least in part this can be attributed to the time dependence of the most dangerous vertical instability mode. Density differences influence the flow primarily by establishing a narrow gravity layer, in which the effective Péclet number is enhanced owing to the higher flow rate. However, buoyancy forces of a certain magnitude can lead to a pinch-off of the gravity layer, thereby slowing it down. Overall, an increase of the gravitational parameter is found to enhance mostly the vertical perturbations, while larger Pe values act towards amplifying horizontal disturbances. The asymptotic rate of growth of the mixing length varies only with Péclet number. For large Péclet numbers, an asymptotic value of 0.7 is observed. A scaling law for the thickness of the gravity layer is obtained as well. In contrast to immiscible flow displacements, it is found to increase with the gravity parameter.

  6. Miscible porous media displacements driven by non-vertical injection wells

    NASA Astrophysics Data System (ADS)

    Upchurch, E.; Meiburg, E.

    High-resolution simulations are employed to identify and analyse the mechanisms dominating miscible porous media displacements generated by inclined injection wells. Compared to vertical injection wells, significant differences are observed that strongly influence breakthrough times and recovery rates. Constant density and viscosity displacements, for which the velocity field is potential in nature, demonstrate the existence of pronounced flow non-uniformities, due to the interaction of the inclined well with the reservoir boundaries. These non-uniformities deform the fronts during the initial displacement stages.In the presence of a viscosity difference, the non-uniformities of the potential flow field result in a focusing of the fingering instability. If the fluids also have different densities, a gravity tongue will reinforce the dominant finger along one front, while a gravitational instability leads to the disintegration of the dominant finger along the other front. Hence, the two fronts emerging from the inclined injection well usually evolve very differently from each other for variable density and viscosity displacements.For inclined injection wells and sufficiently large mobility ratios, gravity tongues are seen to evolve dendritically for an intermediate range of density contrasts. While mild gravitational forces are necessary to create the gravity tongue in the first place, large density differences will suppress the growth of the dendritic side branches. Since the dendritic branches appear along the side of the gravity tongue that should be stable according to traditional stability criteria, it can be concluded that the tip region plays a crucial role in their formation.

  7. Investigation of miscibility of p(3hydroxybutyrate-co-3hydroxyhexanoate) and epoxidized natural rubber blends

    SciTech Connect

    Akram, Faridah; Chan, Chin Han; Natarajan, Valliyappan David

    2015-08-28

    Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate [P(3HB-co-3HHx)] produced by C. necator PHB{sup −}4 harboring phaC{sub cs} from crude palm kernel oil with 21 mol% of 3-hydroxyhexanoate and epoxidized natural rubber with 25 mol% of epoxy content (ENR-25) were used to study the miscibility of the blends by attenuated total reflection-Fourier transform infrared (ATR-FTIR) and differential scanning calorimetry (DSC). The polymers used were purified and the blends were prepared by solution casting method. Nuclear magnetic resonance (NMR) spectra confirm the purity and molecular structures of P(3HB-co-3HHx) and ENR-25. FTIR spectra for different compositions of P(3HB-co-3HHx) and ENR-25 blends show absorbance change of the absorbance bands but with no significant shifting of the absorbance bands as the P(3HB-co-3HHx) content decreases, which shows that there is no intermolecular interaction between the parent polymer blends. On top of that, there are two T{sub g}s present for the blends and both remain constant for different compositions which corresponds to the T{sub g}s of the parent polymers. This indicates that the blends are immiscible.

  8. Antiwear performance and mechanism of an oil-miscible ionic liquid as a lubricant additive.

    PubMed

    Qu, Jun; Bansal, Dinesh G; Yu, Bo; Howe, Jane Y; Luo, Huimin; Dai, Sheng; Li, Huaqing; Blau, Peter J; Bunting, Bruce G; Mordukhovich, Gregory; Smolenski, Donald J

    2012-02-01

    An ionic liquid (IL) trihexyltetradecylphosphonium bis(2-ethylhexyl) phosphate has been investigated as a potential antiwear lubricant additive. Unlike most other ILs that have very low solubility in nonpolar fluids, this IL is fully miscible with various hydrocarbon oils. In addition, it is thermally stable up to 347 °C, showed no corrosive attack to cast iron in an ambient environment, and has excellent wettability on solid surfaces (e.g., contact angle on cast iron <8°). Most importantly, this phosphonium-based IL has demonstrated effective antiscuffing and antiwear characteristics when blended with lubricating oils. For example, a 5 wt % addition into a synthetic base oil eliminated the scuffing failure experienced in neat oil and, as a result, reduced the friction coefficient by 60% and the wear rate by 3 orders of magnitude. A synergistic effect on wear protection was observed with the current antiwear additive when added into a fully formulated engine oil. Nanostructure examination and composition analysis revealed a tribo-boundary film and subsurface plastic deformation zone for the metallic surface lubricated by the IL-containing lubricants. This protective boundary film is believed to be responsible for the IL's antiscuffing and antiwear functionality.

  9. Investigation of miscibility of p(3hydroxybutyrate-co-3hydroxyhexanoate) and epoxidized natural rubber blends

    NASA Astrophysics Data System (ADS)

    Akram, Faridah; Chan, Chin Han; Natarajan, Valliyappan David

    2015-08-01

    Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate [P(3HB-co-3HHx)] produced by C. necator PHB-4 harboring phaCcs from crude palm kernel oil with 21 mol% of 3-hydroxyhexanoate and epoxidized natural rubber with 25 mol% of epoxy content (ENR-25) were used to study the miscibility of the blends by attenuated total reflection-Fourier transform infrared (ATR-FTIR) and differential scanning calorimetry (DSC). The polymers used were purified and the blends were prepared by solution casting method. Nuclear magnetic resonance (NMR) spectra confirm the purity and molecular structures of P(3HB-co-3HHx) and ENR-25. FTIR spectra for different compositions of P(3HB-co-3HHx) and ENR-25 blends show absorbance change of the absorbance bands but with no significant shifting of the absorbance bands as the P(3HB-co-3HHx) content decreases, which shows that there is no intermolecular interaction between the parent polymer blends. On top of that, there are two Tgs present for the blends and both remain constant for different compositions which corresponds to the Tgs of the parent polymers. This indicates that the blends are immiscible.

  10. Anesthetics lower Tc of a 2D miscibility critical point in the plasma membrane

    NASA Astrophysics Data System (ADS)

    Machta, Benjamin; Gray, Elly; Veatch, Sarah

    2014-03-01

    Many small hydrophobic molecules induce general anesthesia. Their efficacy as anesthetics has been shown to correlate both with their hydrophobicity and with their potency in inhibiting certain ligand gated ion channels. I will first report on our experiments on the effects that these molecules have on the two-dimensional miscibility critical point observed in cell derived vesicles (GPMVs). We show that anesthetics depress the critical temperature (Tc) of these GPMVs but do not strongly affect the ratio of phases found below Tc. The magnitude of this affect is consistent across the n-alcohols only when their concentration is rescaled by the median anesthetic concentration (AC50) for tadpole anesthesia and at AC50 we see a 4K downward shift in Tc. I will next present a model in which anesthetics interfere with native allosteric regulation of ligand gated channels by the critical membrane, showing that our observed change in critical properties could lead to the previously observed changes in channel conductance without a direct interaction between anesthetic molecules and their target proteins. Finally, I will discuss ongoing experiments that will clarify the role of this membrane effect in mediating the organism level anesthetic response.

  11. Using Computer-Based Visualization Strategies to Improve Students' Understanding of Molecular Polarity and Miscibility

    NASA Astrophysics Data System (ADS)

    Sanger, Michael J.; Badger, Steven M., II

    2001-10-01

    This study reports how instruction including visualization strategies associated with computer animations and electron density plots affected students' conceptual understanding of two chemistry topics. Two sets of students responded to several conceptual questions about molecular polarities and miscibilities and these responses were compared. One group received instruction including the use of wooden model kits and physical demonstrations; the other received similar instruction with the additional use of computer animations and electron-density plots. Students who viewed electron-density plots were more likely to identify symmetric molecules with polar bonds as being nonpolar and provided more complete descriptions of how soap molecules help remove grease from an object. Students who viewed computer animations and electron density plots were also more likely to explain that the intermolecular attractions among water molecules are responsible for the immiscibility of oil and water, and were more likely to recognize that water molecules are attracted to each other and to sodium and chloride ions but are not strongly attracted to hydrogen molecules. Although other studies have shown that computer animations can improve students' conceptual understanding of chemistry, this is the first to demonstrate that electron-density plots mapped with electrostatic potentials can also be an effective visualization strategy.

  12. Labyrinthine instabilities of miscible magnetic fluids in a rotating Hele-Shaw cell

    NASA Astrophysics Data System (ADS)

    Chen, Mei-Yu; Chen, Li-Que; Li, Huanhao; Wen, Chih-Yung

    2017-02-01

    This study presents the first experimental results of confining miscible magnetic fluids in a rotating Hele-Shaw cell. Variations in the prominence of labyrinthine instabilities are observed under a range of experimental conditions, with different magnetic field strengths, gap depths, and rotation speeds. These instabilities are characterized by two modified Péclect numbers, namely, Pem (the ratio of the characteristic magnetic advection rate and the diffusion rate) and Pec (the ratio of characteristic rotation advection and the diffusion rate). The magnetic effect is characterized by dipolar repulsion, which triggers a distinctive fingering pattern differing from the progressive diffusion pattern that occurs without magnetic fields or rotation. Under the same rotation speed, the magnetoviscous effect will hinder the growth rate of the magnetic drops at the later stage. However, both the rotation effect and the gap depth greatly enhance the growth rate of the magnetic drops, as these conditions help to intensify the labyrinthine instabilities. In contrast, the countering pressure gradient produces an opposite force that constrains the trend toward expansion. Two major phases in the growth of instabilities are defined: a magnetization phase and a rotation phase, which are dominated by the magnetic and the rotation effect, respectively. The significance of the rotation effect is confirmed by the linear regression between the rotation growth rate and Pec. Finally, main fingering structures that evolve from the secondary waves are verified as having a wavelength λ to gap depth h relation of λ ≈(7 ±1 ) h .

  13. Flood Risk Management in Hungary's Upper Tisza Basin: the Potential Use of a Flood Catastrophe Model

    NASA Astrophysics Data System (ADS)

    Linerooth-Bayer, J.; Ermoliev, Y.; Ermolieva, T.; Galambos, I.

    2001-05-01

    This paper is based on the preliminary results of an IIASA-based study of flood-risk management for the Hungarian Upper Tisza River, where recent devastating floods have been exacerbated by cyanide and heavy metal pollution episodes originating in Romania. Hungary ranks only behind countries like Bangladesh and the Netherlands with regard to the extent of its territory exposed to flood risks, yet the government does not have a clear risk-management strategy in place. In the past, the national government has taken full responsibility for flood prevention, mainly through the construction of dikes, as well as for the post-disaster compensation of losses. This policy, however, is placing an increasing strain on the national budget. Like in many other countries, Hungarians recognize that a national flood program must be developed that effectively links private and public responsibility for the losses, private insurance and loss mitigation. The development of an insurance/mitigation program, however, faces distributive-value problems (the Hungarian public is skeptical of private insurance). Moreover, if private insurance is to be a policy option, it is necessary to devise improved tools and models for estimating spatially dependent risks in cases of little historical data. This is an area in which hydrologic models can be particularly useful. In this discussion, we describe a flood catastrophe model based on Monte Carlo simulation that can be of use in analyzing policy options for reducing the losses of floods in the Upper Tisza region, as well as for improving the insurability of the losses. The policy scenarios examined in the model, which are limited by data availability, have been developed by Hungarian policy makers. While the results are modest, the study demonstrates a methodology and process that may have considerable potential for aiding Hungarian policy makers in designing a national flood program.

  14. Past and future flooding in Bangladesh

    NASA Astrophysics Data System (ADS)

    Thiele-Eich, Insa; Hopson, Thomas; Simmer, Clemens; Simon, Thorsten

    2016-04-01

    Currently, an average of about 20 % of the land surface in Bangladesh is flooded each year, affecting one of the most densely populated regions in the world. We aim to understand the processes currently determining flooding in the Ganges-Brahmaputra-Meghna (GBM) basin, in particular the role of precipitation and sea-level rise, as well as to assess how climate change might impact flood characteristics in the future. Water level and discharge data were provided by the Bangladesh Water Development Board on a daily basis for a period of 1909-2009. Monthly maps based on daily sea level anomalies from the Data Unification Altimeter Combination System DUACS are available on a 0.25° by 0.25° grid for the time period 1993-2014. Ensemble model output for upper catchment precipitation and annual mean thermosteric sea-level rise is taken from historical and RCP scenario runs conducted with the CCSM4. We first analyzed daily water levels of the past 100 years in order to detect potential shifts in extremes. The available observations are then used to set up a generalized linear model to detect how precipitation influences flooding in the GBM basin. This model can then be used to give a prognosis on changes in future flooding. Our analysis suggests that water levels have indeed changed over the course of the past century. While the magnitude and duration of average flood events decreased, the frequency of extreme flood events has increased. Low water levels have also changed, with a significant decrease in the annual minimum water level most noticeable when we compare the time periods 1909-1939 and 1979-2009. For the future, first results confirm the decrease in return periods of strong flood events found in previous studies. The impact of climate change on flooding will also be compared to the impact of man-made structures such as Farakka barrage, built across the Ganges on the border between India and Bangladesh and operating since 1975. This is of particular interest as

  15. Rethinking the relationship between flood risk perception and flood management.

    PubMed

    Birkholz, S; Muro, M; Jeffrey, P; Smith, H M

    2014-04-15

    Although flood risk perceptions and their concomitant motivations for behaviour have long been recognised as significant features of community resilience in the face of flooding events, there has, for some time now, been a poorly appreciated fissure in the accompanying literature. Specifically, rationalist and constructivist paradigms in the broader domain of risk perception provide different (though not always conflicting) contexts for interpreting evidence and developing theory. This contribution reviews the major constructs that have been applied to understanding flood risk perceptions and contextualises these within broader conceptual developments around risk perception theory and contemporary thinking around flood risk management. We argue that there is a need to re-examine and re-invigorate flood risk perception research, in a manner that is comprehensively underpinned by more constructivist thinking around flood risk management as well as by developments in broader risk perception research. We draw attention to an historical over-emphasis on the cognitive perceptions of those at risk to the detriment of a richer understanding of a wider range of flood risk perceptions such as those of policy-makers or of tax-payers who live outside flood affected areas as well as the linkages between these perspectives and protective measures such as state-supported flood insurance schemes. Conclusions challenge existing understandings of the relationship between risk perception and flood management, particularly where the latter relates to communication strategies and the extent to which those at risk from flooding feel responsible for taking protective actions.

  16. The Stanford Flood.

    ERIC Educational Resources Information Center

    Leighton, Philip D.

    1979-01-01

    Describes, from the flood to the start of freeze-drying operations, the preservation efforts of Stanford University regarding books damaged by water in the Green Library in November 1978. Planning, action, and mopping-up activities are chronicled, and 20 suggestions are offered as guidance in future similar situations. (JD)

  17. After the Flood

    ERIC Educational Resources Information Center

    Stanistreet, Paul

    2007-01-01

    When floodwater swept through the McVities biscuit factory in Carlisle in January 2005 few were confident that it would reopen. The factory, in the Caldewgate area of the city, was one of the first casualties of the flood, as water, nine feet deep in places, coursed trough the food preparation areas, destroying equipment and covering everything in…

  18. Flooding on Elbe River

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Heavy rains in Central Europe over the past few weeks have led to some of the worst flooding the region has witnessed in more than a century. The floods have killed more than 100 people in Germany, Russia, Austria, Hungary, and the Czech Republic and have led to as much as $20 billion in damage. This false-color image of the Elbe River and its tributaries was taken on August 20, 2002, by the Moderate Resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra satellite. The floodwaters that inundated Dresden, Germany, earlier this week have moved north. As can be seen, the river resembles a fairly large lake in the center of the image just south of the town of Wittenberg. Flooding was also bad further downriver in the towns of Maqgdeburge and Hitzacker. Roughly 20,000 people were evacuated from their homes in northern Germany. Fifty thousand troops, border police, and technical assistance workers were called in to combat the floods along with 100,000 volunteers. The floodwaters are not expected to badly affect Hamburg, which sits on the mouth of the river on the North Sea. Credit:Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

  19. Hydrologic Flood Routing.

    ERIC Educational Resources Information Center

    Heggen, Richard J.

    1982-01-01

    Discusses a short classroom-based BASIC program which routes stream flow through a system of channels and reservoirs. The program is suitable for analyses of open channel conveyance systems, flood detention reservoirs, and combinations of the two. (Author/JN)

  20. Rapid Exposure Assessment of Nationwide River Flood for Disaster Risk Reduction

    NASA Astrophysics Data System (ADS)

    Kwak, Y.; Park, J.; Arifuzzaman, B.; Iwami, Y.; Amirul, Md.; Kondoh, A.

    2016-06-01

    considerably increased. For flood disaster risk reduction, it is important to identify and characterize flood area, locations (particularly lowland along rivers), and durations. For this purpose, flood mapping and monitoring are an imperative process and the fundamental part of risk management as well as emergency response. Our ultimate goal is to detect flood inundation areas over a nationwide scale despite limitations of optical and multispectral images, and to estimate flood risk in terms of affected people. We propose a methodological possibility to be used as a standard approach for nationwide rapid flood exposure assessment with the use of the multi-temporal Moderate Resolution Imaging Spectrometer (MODIS), a big contributor to progress in near-real-time flood mapping. The preliminary results in Bangladesh show that a propensity of flood risk change strongly depends on the temporal and spatial dynamics of exposure such as distributed population.

  1. Based on GIS technology flood disaster assessment study of Fuhe River Basin

    NASA Astrophysics Data System (ADS)

    Wu, Dingding; Zhao, Xinyu; Chen, Jing

    2014-01-01

    Flood protection of Fuhe river basin has been payed high attention after Changkai-levee crevasse in 2010. This paper constructions a model of flood disaster lose calculation considering flood disaster and social economic developing based on GIS. Firstly social economic indexes have been selected according to characteristics of the urban and the rural. Secondly a mathematical model of flood routing using Finite Volume Method has been made in spacial information grids, the data of inundated depth and flood duration can be extracted from the grids. In the end ,wo calculate the loss by flood disaster losses calculation process model. This paper solves the stacking problem of flood characteristic and administrative boundaries effectively, which makes a development on accuracy of flood disaster assessment.

  2. Attribution of regional flood changes based on scaling fingerprints

    NASA Astrophysics Data System (ADS)

    Viglione, Alberto; Merz, Bruno; Viet Dung, Nguyen; Parajka, Juraj; Nester, Thomas; Blöschl, Günter

    2016-07-01

    Changes in the river flood regime may be due to atmospheric processes (e.g., increasing precipitation), catchment processes (e.g., soil compaction associated with land use change), and river system processes (e.g., loss of retention volume in the floodplains). This paper proposes a new framework for attributing flood changes to these drivers based on a regional analysis. We exploit the scaling characteristics (i.e., fingerprints) with catchment area of the effects of the drivers on flood changes. The estimation of their relative contributions is framed in Bayesian terms. Analysis of a synthetic, controlled case suggests that the accuracy of the regional attribution increases with increasing number of sites and record lengths, decreases with increasing regional heterogeneity, increases with increasing difference of the scaling fingerprints, and decreases with an increase of their prior uncertainty. The applicability of the framework is illustrated for a case study set in Austria, where positive flood trends have been observed at many sites in the past decades. The individual scaling fingerprints related to the atmospheric, catchment, and river system processes are estimated from rainfall data and simple hydrological modeling. Although the distributions of the contributions are rather wide, the attribution identifies precipitation change as the main driver of flood change in the study region. Overall, it is suggested that the extension from local attribution to a regional framework, including multiple drivers and explicit estimation of uncertainty, could constitute a similar shift in flood change attribution as the extension from local to regional flood frequency analysis.

  3. Scoping of Flood Hazard Mapping Needs for Penobscot County, Maine

    USGS Publications Warehouse

    Schalk, Charles W.; Dudley, Robert W.

    2007-01-01

    Background The Federal Emergency Management Agency (FEMA) developed a plan in 1997 to modernize the FEMA flood mapping program. FEMA flood maps delineate flood hazard areas in support of the National Flood Insurance Program (NFIP). FEMA's plan outlined the steps necessary to update FEMA's flood maps for the nation to a seamless digital format and streamline FEMA's operations in raising public awareness of the importance of the maps and responding to requests to revise them. The modernization of flood maps involves conversion of existing information to digital format and integration of improved flood hazard data as needed. To determine flood mapping modernization needs, FEMA has established specific scoping activities to be done on a county-by-county basis for identifying and prioritizing requisite flood-mapping activities for map modernization. The U.S. Geological Survey (USGS), in cooperation with FEMA and the Maine State Planning Office Floodplain Management Program (MFMP), began scoping work in 2006 for Penobscot County. Scoping activities included assembling existing data and map needs information for communities in Penobscot County, documentation of data, contacts, community meetings, and prioritized mapping needs in a final scoping report (this document), and updating the Mapping Needs Update Support System (MNUSS) Database with information gathered during the scoping process. As of 2007, the average age of the FEMA floodplain maps in Penobscot County, Maine, is 22 years, based on the most recent revisions to the maps. Because the revisions did not affect all the map panels in each town, however, the true average date probably is more than 22 years. Many of the studies were published in the mid-1980s. Since the studies were completed, development has occurred in many of the watersheds, and the characteristics of the watersheds have changed with time. Therefore, many of the older studies may not depict current conditions nor accurately estimate risk in terms

  4. Scoping of Flood Hazard Mapping Needs for Hancock County, Maine

    USGS Publications Warehouse

    Schalk, Charles W.; Dudley, Robert W.

    2007-01-01

    Background The Federal Emergency Management Agency (FEMA) developed a plan in 1997 to modernize the FEMA flood mapping program. FEMA flood maps delineate flood hazard areas in support of the National Flood Insurance Program (NFIP). FEMA's plan outlined the steps necessary to update FEMA's flood maps for the nation to a seamless digital format and streamline FEMA's operations in raising public awareness of the importance of the maps and responding to requests to revise them. The modernization of flood maps involves conversion of existing information to digital format and integration of improved flood hazard data as needed. To determine flood mapping modernization needs, FEMA has established specific scoping activities to be done on a county-by-county basis for identifying and prioritizing requisite flood-mapping activities for map modernization. The U.S. Geological Survey (USGS), in cooperation with FEMA and the Maine Floodplain Management Program (MFMP) State Planning Office, began scoping work in 2006 for Hancock County. Scoping activities included assembling existing data and map needs information for communities in Hancock County, documentation of data, contacts, community meetings, and prioritized mapping needs in a final scoping report (this document), and updating the Mapping Needs Update Support System (MNUSS) database with information gathered during the scoping process. The average age of the FEMA floodplain maps (all types) in Hancock County, Maine, is at least 19 years. Most of these studies were published in the late 1980s and early 1990s, and no study is more recent than 1992. Some towns have partial maps that are more recent than their study, indicating that the true average age of the data is probably more than 19 years. Since the studies were done, development has occurred in some of the watersheds and the characteristics of the watersheds have changed. Therefore, many of the older studies may not depict current conditions or accurately estimate

  5. Scoping of Flood Hazard Mapping Needs for Lincoln County, Maine

    USGS Publications Warehouse

    Schalk, Charles W.; Dudley, Robert W.

    2007-01-01

    Background The Federal Emergency Management Agency (FEMA) developed a plan in 1997 to modernize the FEMA flood mapping program. FEMA flood maps delineate flood hazard areas in support of the National Flood Insurance Program (NFIP). FEMA's plan outlined the steps necessary to update FEMA's flood maps for the nation to a seamless digital format and streamline FEMA's operations in raising public awareness of the importance of the maps and responding to requests to revise them. The modernization of flood maps involves conversion of existing information to digital format and integration of improved flood hazard data as needed. To determine flood mapping modernization needs, FEMA has established specific scoping activities to be done on a county-by-county basis for identifying and prioritizing requisite flood-mapping activities for map modernization. The U.S. Geological Survey (USGS), in cooperation with FEMA and the Maine Floodplain Management Program (MFMP) State Planning Office, began scoping work in 2006 for Lincoln County. Scoping activities included assembling existing data and map needs information for communities in Lincoln County, documentation of data, contacts, community meetings, and prioritized mapping needs in a final scoping report (this document), and updating the Mapping Needs Update Support System (MNUSS) database with information gathered during the scoping process. The average age of the FEMA floodplain maps in Lincoln County, Maine is at least 17 years. Many of these studies were published in the mid- to late-1980s, and some towns have partial maps that are more recent than their study. However, in the ensuing 15-20 years, development has occurred in many of the watersheds, and the characteristics of the watersheds have changed with time. Therefore, many of the older studies may not depict current conditions nor accurately estimate risk in terms of flood heights or flood mapping.

  6. Scoping of Flood Hazard Mapping Needs for Androscoggin County, Maine

    USGS Publications Warehouse

    Schalk, Charles W.; Dudley, Robert W.

    2007-01-01

    Background The Federal Emergency Management Agency (FEMA) developed a plan in 1997 to modernize the FEMA flood mapping program. FEMA flood maps delineate flood hazard areas in support of the National Flood Insurance Program (NFIP). FEMA's plan outlined the steps necessary to update FEMA's flood maps for the nation to a seamless digital format and streamline FEMA's operations in raising public awareness of the importance of the maps and responding to requests to revise them. The modernization of flood maps involves conversion of existing information to digital format and integration of improved flood hazard data as needed and as funds allow. To determine flood mapping modernization needs, FEMA has established specific scoping activities to be done on a county-by-county basis for identifying and prioritizing requisite flood-mapping activities for map modernization. The U.S. Geological Survey (USGS), in cooperation with FEMA and the Maine Floodplain Management Program (MFMP) State Planning Office, began scoping work in 2006 for Androscoggin County. Scoping activities included assembling existing data and map needs information for communities in Androscoggin County, documentation of data, contacts, community meetings, and prioritized mapping needs in a final scoping report (this document), and updating the Mapping Needs Update Support System (MNUSS) Database with information gathered during the scoping process. The average age of the FEMA floodplain maps in Androscoggin County, Maine, is at least 17 years. Most studies were published in the early 1990s, and some towns have partial maps that are more recent than their study date. Since the studies were done, development has occurred in many of the watersheds and the characteristics of the watersheds have changed with time. Therefore, many of the older studies may not depict current conditions nor accurately estimate risk in terms of flood heights or flood mapping.

  7. Changes in flood risk in Europe - Holistic perspective

    NASA Astrophysics Data System (ADS)

    Kundzewicz, Z. W.

    2012-04-01

    Fluvial foods, associated with high river flows and stages, have become more abundant and more destructive than ever in many regions of the globe, including Europe. The present contribution asks: Has flood risk increased in Europe, how, where, and why? How do socio-economic trends and associated land-use change contribute to the risk? Are climate change impacts apparent? The material draws from the multi-authored book "Changes in Flood Risk in Europe" edited by Z. W. Kundzewicz, and published by IAHS Press in March 2012, that embraces many national and regional studies. Changes in flood risk is regarded in a holistic cradle-to-grave perspective, driven by a chain of processes and variables, from the realm of climatic, terrestrial, and socio-economic systems. There are multiple factors contributing to the growth of flood risk that differ for various regions and flood generation mechanisms. It can be hypothesised that the anthropogenic influence plays a major role, via increase in exposure to floods and damage potential. The questions about the impact of land-use change and climate change (viz. ubiquitous warming and changes in intense precipitation) on flood hazard and flood risk are more complex. There is little doubt that a multi-factor situation, weakness of the climate change signal and a strong natural variability render the detection and attribution problems very difficult. No ubiquitous, general, and significant changes in observed flood flows can be detected, even at a national scale, and dissemination of this finding is very important. However, in some regions, changes in intense precipitation and in frequency of flood-prone climate circulation patterns were spotted, as well as climate-related trends in flood indicators.

  8. Flooding in counter-current two-phase flow

    SciTech Connect

    Ragland, W.A.; Ganic, E.N.

    1982-01-01

    Flooding is a phenomenon which is best described as the transition from counter-current to co-current flow. Early notice was taken of this phenomenon in the chemical engineering industry. Flooding also plays an important role in the field of two-phase heat transfer since it is a limit for many systems involving counter-current flow. Practical applications of flooding limited processes include wickless thermosyphons and the emergency core cooling system (ECCS) of pressurized water nuclear reactors. The phenomenon of flooding also is involved in the behavior of nuclear reactor core materials during severe accident conditions where flooding is one of the mechanisms governing the motion of the molten fuel pin cladding.

  9. Flood risk assessment and mapping for the Lebanese watersheds

    NASA Astrophysics Data System (ADS)

    Abdallah, Chadi; Hdeib, Rouya

    2016-04-01

    Of all natural disasters, floods affect the greatest number of people worldwide and have the greatest potential to cause damage. Nowadays, with the emerging global warming phenomenon, this number is expected to increase. The Eastern Mediterranean area, including Lebanon (10452 Km2, 4.5 M habitant), has witnessed in the past few decades an increase frequency of flooding events. This study profoundly assess the flood risk over Lebanon covering all the 17 major watersheds and a number of small sub-catchments. It evaluate the physical direct tangible damages caused by floods. The risk assessment and evaluation process was carried out over three stages; i) Evaluating Assets at Risk, where the areas and assets vulnerable to flooding are identified, ii) Vulnerability Assessment, where the causes of vulnerability are assessed and the value of the assets are provided, iii) Risk Assessment, where damage functions are established and the consequent damages of flooding are estimated. A detailed Land CoverUse map was prepared at a scale of 1/ 1 000 using 0.4 m resolution satellite images within the flood hazard zones. The detailed field verification enabled to allocate and characterize all elements at risk, identify hotspots, interview local witnesses, and to correlate and calibrate previous flood damages with the utilized models. All filed gathered information was collected through Mobile Application and transformed to be standardized and classified under GIS environment. Consequently; the general damage evaluation and risk maps at different flood recurrence periods (10, 50, 100 years) were established. Major results showed that floods in a winter season (December, January, and February) of 10 year recurrence and of water retention ranging from 1 to 3 days can cause total damages (losses) that reach 1.14 M for crop lands and 2.30 M for green houses. Whereas, it may cause 0.2 M to losses in fruit trees for a flood retention ranging from 3 to 5 days. These numbers differs

  10. Understanding the geomorphology of macrochannel systems for flood risk management in Queensland, Australia

    NASA Astrophysics Data System (ADS)

    Thompson, Chris; Croke, Jacky

    2016-04-01

    The year 2010-2011 was the wettest on record for the state of Queensland, Australia producing catastrophic floods. A tropical low pressure system in 2013 delivered further extreme flood events across South East Queensland (SEQ) which prompted state and local governments to conduct studies into flood magnitude and frequency in the region and catchment factors contributing to flood hazards. The floods in the region are strongly influenced by El Nino-Southern Oscillation (ENSO) phenomenon, but also modulated by the Interdecadal Pacific Oscillation (IPO) which leads to flood and drought dominated regimes and high hydrological variability. One geomorphic feature in particular exerted a significant control on the transmission speed, the magnitude of flood inundation and resultant landscape resilience. This feature was referred to as a 'macrochannel', a term used to describe a 'large-channel' which has bankfull recurrence intervals generally greater than 10 years. The macrochannels display non-linear downstream hydraulic geometry which leads to zones of flood expansion (when hydraulic geometry decreases) and zones of flood contraction (when hydraulic geometry increases). The pattern of contraction and expansion zones determines flood hazard zones. The floods caused significant wet flow bank mass failures that mobilised over 1,000,000 m3 of sediment in one subcatchment. Results suggest that the wetflow bank mass failures are a stage in a cyclical evolution process which maintains the macrochannel morphology, hence channel resilience to floods. Chronological investigations further show the macrochannels are laterally stable and identify periods of heightened flood activity over the past millennium and upper limits on flood magnitude. This paper elaborates on the results of the geomorphic investigations on Lockyer Creek in SEQ and how the results have alerted managers and policy makers to the different flood responses of these systems and how flood risk management plans can

  11. Synthetic generation of arbitrarily long series of flood hydrographs for flood risk assessment

    NASA Astrophysics Data System (ADS)

    Flores, Isabel; Sordo-Ward, Alvaro; Mediero, Luis; Garrote, Luis

    2013-04-01

    Flood risk assessment is an essential component of natural disaster management. Flood frequency analysis has traditionally been approached by fitting relatively short series of annual maxima of observations to a parametric probability distribution. Under this approach, only one relevant variable (usually peak discharge) can be analyzed, while in many practical applications, like dam safety analysis, the entire flood hydrograph is of interest. Obtaining a good representation of the ensemble of hydrographs would require extremely long historical flood series which almost never exist. Hydrometeorological modelling tools can be applied to extend the relatively short series of observations and generate an arbitrarily long series of synthetic events that can be used in flood risk assessment. The heavy computational burden of these processes requires the contribution of Information and Communication Technology (ICT) developments to enable the practical application of the hydrometeorological modelling chain for this purpose. In this paper, an example of this methodology is applied to the Santillana reservoir, located in the Manzanares basin, in Spain. The methodology is based on the Monte Carlo generation of synthetic hydrographs from rainstorms events extracted from arbitrarily long synthetic rainfall time series. The rainfall series are generated with the RainSim software, a model based on a spatial-temporal Neyman-Scott rectangular pulses process. The highest event of every year is chosen, based on three different criterions. The selected rainstorm events are transformed into runoff by the RIBS distributed rainfall-runoff event model, obtaining the ensemble of hydrographs which make possible to evaluate the associated flood risk. The procedure has been validated by comparing the observed flood frequency series in the Santillana reservoir with the synthetic ones, obtaining a good agreement.

  12. Study of Beijiang catchment flash-flood forecasting model

    NASA Astrophysics Data System (ADS)

    Chen, Y.; Li, J.; Huang, S.; Dong, Y.

    2015-05-01

    Beijiang catchment is a small catchment in southern China locating in the centre of the storm areas of the Pearl River Basin. Flash flooding in Beijiang catchment is a frequently observed disaster that caused direct damages to human beings and their properties. Flood forecasting is the most effective method for mitigating flash floods, the goal of this paper is to develop the flash flood forecasting model for Beijiang catchment. The catchment property data, including DEM, land cover types and soil types, which will be used for model construction and parameter determination, are downloaded from the website freely. Based on the Liuxihe Model, a physically based distributed hydrological model, a model for flash flood forecasting of Beijiang catchment is set up. The model derives the model parameters from the terrain properties, and further optimized with the observed flooding process, which improves the model performance. The model is validated with a few observed floods occurred in recent years, and the results show that the model is reliable and is promising for flash flood forecasting.

  13. Intelligent Real-Time Reservoir Operation for Flood Control

    NASA Astrophysics Data System (ADS)

    Chang, L.; Hsu, H.

    2008-12-01

    Real-time flood control of a multi-purpose reservoir should consider decreasing the flood peak stage downstream and storing floodwaters for future usage during typhoon seasons. It is a continuous and instant decision-making process based on relevant operating rules, policy and water laws, in addition the immediate rainfall and the hydrology information; however, it is difficult to learn the intelligent experience from the elder operators. The main purpose of this study is to establish the automatic reservoir flood control model to achieve the goal of a reservoir operation during flood periods. In this study, we propose an intelligent reservoir operating methodology for real-time flood control. First, the genetic algorithm is used to search the optimal solutions, which can be considered as extracting the knowledge of reservoir operation strategies. Then, the adaptive network-based fuzzy inference system (ANFIS), which uses a hybrid learning procedure for extracting knowledge in the form of fuzzy if-then rules, is used to learn the input-output patterns and then to estimate the optimal flood operation. The Shihmen reservoir in Northern Taiwan was used as a case study, where its 26 typhoon events are investigated by the proposed method. The results demonstrate that the proposed control model can perform much better than the original reservoir operator in 26 flood events and effectively achieve decreasing peak flood stage downstream and storing floodwaters for future usage.

  14. Accounting for rainfall systematic spatial variability in flash flood forecasting

    NASA Astrophysics Data System (ADS)

    Douinot, Audrey; Roux, Hélène; Garambois, Pierre-André; Larnier, Kévin; Labat, David; Dartus, Denis

    2016-10-01

    Just as with the storms that cause them, flash floods are highly variable and non-linear phenomena in both time and space; hence understanding and anticipating the genesis of flash floods is far from straightforward. There is therefore a huge requirement for tools with the potential to provide advance warning of situations likely to lead to flash floods, and thus provide additional time for the flood forecasting services. The Flash Flood Guidance (FFG) method is used on US catchments to estimate the average number of inches of rainfall for given durations required to produce flash flooding. This rainfall amount is used afterwards as a flood warning threshold. In Europe, flash floods often occur on small catchments (approximately 100 km2) and it has already been shown that the spatial variability of rainfall has a great impact on the catchment response (Le Lay and Saulnier, 2007). Therefore, in this study, an improved FFG method which accounts for rainfall spatial variability is proposed. The objectives of this paper are (i) to assess the FFG method applicability on French Mediterranean catchments with a distributed process-oriented hydrological model and (ii) to assess the effect of the rainfall spatial variability on this method. The results confirm the influence of the spatial variability of rainfall events in relation with its interaction with soil properties.

  15. Floods at Mount Clemens, Michigan

    USGS Publications Warehouse

    Wiitala, S.W.; Ash, Arlington D.

    1962-01-01

    The approximate areas inundated during the flood of April 5-6, 1947, by Clinton River, North Branch and Middle Branch of Clinton River, and Harrington Drain, in Clinton Township, Macomb County, Mich., are shown on a topographic map base to record the flood hazard in graphical form. The flood of April 1947 is the highest known since 1934 and probably since 1902. Greater floods are possible, but no attempt was made to define their probable overflow limits.The Clinton River Cut-Off Canal, a flood-relief channel which diverts flow directly into Lake St. Clair from a point about 1500 feet downstream from Gratiot Avenue (about 9 miles upstream from the mouth) has been in operation since October 1951. The approximate limits of overflow that would results from a flood equivalent in discharge to that of April 1947, and occurring with the Cut-Off Canal in operation, are also shown. Although the Cut-Off Canal may reduce the frequency and depth of flooding it will not necessarily eliminate future flooding in the area. Improvements and additions to the drainage systems in the basin, expanding urbanization, new highways, and other cultural changes may influence the inundation pattern of future floods.The preparation of this flood inundation map was financed through a cooperative agreement between Clinton Township, Macomb County, Mich., and the U.S. Geological Survey.Backwater curves used to define the profile for a hypothetical flood on the Clinton River downstream from Moravian Drive, equivalent in discharge to the 1947 flood, but occurring with the present Cut-Off Canal in operation; flood stage established at the gaging station on Clinton River at Mount Clemens; and supplementary floodmark elevations were furnished by the Corps of Engineers.Bench-mark elevations and field survey data, used in the analysis of floods on Harrington Drain, were furnished by the Macomb County Drain Commission.

  16. Extending RST-FLOOD to thermal infrared data: a possible operational strategy for flooded areas detection in near real time

    NASA Astrophysics Data System (ADS)

    Faruolo, Mariapia; Coviello, Irina; Lacava, Teodosio; Pergola, Nicola; Tramutoli, Valerio

    2013-04-01

    In the recent years the use of remote sensing data has been growing rapidly in the flood risk context, because they can offer the possibility to support hydrological and hydraulic analyses aimed at both improving flood inundation models and better understanding hydrodynamic processes for managing flood emergency. Optical sensors aboard meteorological satellites may provide a useful contribution for a rapid detection and mapping of areas interested by a flood. Such sensors, being able to guarantee a steady and frequent stream of images (with a temporal resolution variable from hours to minutes), have in fact a great potential for near real time monitoring of flood evolution. Actually, to be effectively used for supporting flood risk management and assessment, such kind of data must be analyzed using reliable earth observation (EO) techniques in order to guarantee consistent results regardless of the used data/sensor. The methodology used and shown in this paper has been moving in this direction. Such a methodology, known as RST (Robust Satellite Techniques) approach (in the paper named RST-FLOOD to indicate its specific application to flood risk) and based entirely on satellite remote sensing data, is a multi-temporal scheme of data analysis which identifies statistically significant anomalies of the investigated signal on the basis of a preliminary characterization of the signal in normal (i.e. unperturbed) conditions. Its implementation on visible and near infrared bands of AVHRR (Advanced Very High Resolution Radiometer) and MODIS (Moderate Resolution Imaging Spectroradiometer) sensors, for studying different flooding events occurred worldwide, already showed it