Sample records for reservoir level constraints

  1. Electricity production in a hydro system with a reservoir constraint

    Energy Technology Data Exchange (ETDEWEB)

    Mathiesen, Lars; Skaar, Jostein; Soergard, Lars


    The purpose of this article is to analyze how market power may affect the allocation of production between seasons (summer and winter) in a hydro power system with reservoir constraints and inflow uncertainty. We find that even without market power the price in the summer season may be lower than the expected price in the winter season. Market power may in some situations lead to higher sales and lower price in summer than the competitive outcome and in other situations to the opposite result. Furthermore, market power may lead to a smaller price difference between summer and winter than in a competitive market. (Author)

  2. Hydroeconomic optimization of reservoir management under downstream water quality constraints

    DEFF Research Database (Denmark)

    Davidsen, Claus; Liu, Suxia; Mo, Xingguo


    A hydroeconomic optimization approach is used to guide water management in a Chinese river basin with the objectives of meeting water quantity and water quality constraints, in line with the China 2011 No. 1 Policy Document and 2015 Ten-point Water Plan. The proposed modeling framework couples...... water quantity and water quality management and minimizes the total costs over a planning period assuming stochastic future runoff. The outcome includes cost-optimal reservoir releases, groundwater pumping, water allocation, wastewater treatments and water curtailments. The optimization model uses...... a variant of stochastic dynamic programming known as the water value method. Nonlinearity arising from the water quality constraints is handled with an effective hybrid method combining genetic algorithms and linear programming. Untreated pollutant loads are represented by biochemical oxygen demand (BOD...

  3. Hydroeconomic optimization of reservoir management under downstream water quality constraints (United States)

    Davidsen, Claus; Liu, Suxia; Mo, Xingguo; Holm, Peter E.; Trapp, Stefan; Rosbjerg, Dan; Bauer-Gottwein, Peter


    A hydroeconomic optimization approach is used to guide water management in a Chinese river basin with the objectives of meeting water quantity and water quality constraints, in line with the China 2011 No. 1 Policy Document and 2015 Ten-point Water Plan. The proposed modeling framework couples water quantity and water quality management and minimizes the total costs over a planning period assuming stochastic future runoff. The outcome includes cost-optimal reservoir releases, groundwater pumping, water allocation, wastewater treatments and water curtailments. The optimization model uses a variant of stochastic dynamic programming known as the water value method. Nonlinearity arising from the water quality constraints is handled with an effective hybrid method combining genetic algorithms and linear programming. Untreated pollutant loads are represented by biochemical oxygen demand (BOD), and the resulting minimum dissolved oxygen (DO) concentration is computed with the Streeter-Phelps equation and constrained to match Chinese water quality targets. The baseline water scarcity and operational costs are estimated to 15.6 billion CNY/year. Compliance to water quality grade III causes a relatively low increase to 16.4 billion CNY/year. Dilution plays an important role and increases the share of surface water allocations to users situated furthest downstream in the system. The modeling framework generates decision rules that result in the economically efficient strategy for complying with both water quantity and water quality constraints.

  4. Thermoelastic properties of the Rotokawa Andesite: A geothermal reservoir constraint (United States)

    Siratovich, P. A.; von Aulock, F. W.; Lavallée, Y.; Cole, J. W.; Kennedy, B. M.; Villeneuve, M. C.


    Knowledge of the thermal properties of geothermal reservoir rocks is essential to constraining important engineering concerns such as wellbore stability, reservoir forecasting and stimulation procedures. The thermo-mechanical evolution of geological material is also important to assess when considering natural processes such as magmatic dyke propagation, contact metamorphism and magma/lava emplacement and cooling effects. To better constrain these properties in the geothermal reservoir, thermal measurements were carried out on core samples from production wells drilled in the Rotokawa Andesite geothermal reservoir, located in the Taupo Volcanic Zone, New Zealand. Linear thermal expansion testing, thermogravimetric analysis, and differential scanning calorimetry were used, employing experimental heating rates of 2, 5 and 20 °C/min. Thermal property analyses can elucidate whether thermal expansion values measured under varied heating (and cooling) rates are rate dependent and if thermo-chemical reactions influence the resultant expansivity. Measured thermal expansion coefficients of the Rotokawa Andesite are shown not to be heating rate dependent. We have also found that significant thermochemical reactions occur during heating above 500 °C resulting in non-reversible changes to the thermomechanical properties. The combined thermogravimetric, calorimetric and thermomechanical analysis allows insight to the reactions occurring and how the thermomechanical properties are affected at high temperature. We incorporated results of tensile strength testing on the Rotokawa Andesite to apply our thermal property measurements to a one-dimensional thermal stress model. The developed model provides a failure criterion for the Rotokawa Andesite under thermal stress. The importance of this study is to further understand the critical heating and cooling rates at which thermal stress may cause cracking within the Rotokawa reservoir. Thermal cracking in the reservoir can be

  5. Multiple shooting applied to robust reservoir control optimization including output constraints on coherent risk measures

    DEFF Research Database (Denmark)

    Codas, Andrés; Hanssen, Kristian G.; Foss, Bjarne


    . In this work, we propose a new formulation for robust optimization of reservoir well controls. It is inspired by the multiple shooting (MS) method which permits a broad range of parallelization opportunities and output constraint handling. This formulation exploits coherent risk measures, a concept...... traditionally used in finance, to bound the risk on constraint violation. We propose a reduced sequential quadratic programming (rSQP) algorithm to solve the underlying optimization problem. This algorithm exploits the structure of the coherent risk measures, thus a large set of constraints are solved within...... sub-problems. Moreover, a variable elimination procedure allows solving the optimization problem in a reduced space and an iterative active-set method helps to handle a large set of inequality constraints. Finally, we demonstrate the application of constraints to bound the risk of water production...

  6. Lithofacies and associated reservoir properties co-simulations constraint by seismic data; Cosimulations de lithofacies et de proprietes reservoirs associees contraintes par les donnees sismiques

    Energy Technology Data Exchange (ETDEWEB)

    Fichtl, P.


    Integration of data different sources and nature leads to more accurate reservoir models, useful for controlling fluid and assessing final uncertainties. In this frame, this thesis presents a new technique for co-simulating in 3D two high resolution properties - one categorical, one continuous - conditionally to well information and under the constraint of seismic data. This technique could be applied to simulate lithofacies and related reservoir properties like acoustic impedances or porosities. The proposed algorithm combines a non-parametric approach for the categorical variable and a parametric approach for the continuous variable through a sequential co-simulation. The co-simulation process is divided in two steps: in the first step, the lithofacies is co-simulated with the seismic information by a sequential indicator co-simulation with co-kriging and, in the second step, the reservoir property of interest is simulated from the previously co-simulated lithofacies using sequential Gaussian (co- )simulation or P-field simulation. A validation study on a synthetic but realistic model shows that this technique provides alternative models of lithofacies and associated high resolution acoustic impedances consistent with the seismic data. The seismic information constraining the co-simulations contributes to reduce the uncertainties for the lithofacies distribution at the reservoir level. In some case, a Markov co-regionalization model can be used for simplifying the inference and modelling of the cross-covariances; finally, the co-simulation algorithm was applied to a 3D real case study with objective the joint numerical modelling of lithofacies and porosity in a fluvial channel reservoir. (author) 88 refs.

  7. Integrated reservoir characterization: Improvement in heterogeneities stochastic modelling by integration of additional external constraints

    Energy Technology Data Exchange (ETDEWEB)

    Doligez, B.; Eschard, R. [Institut Francais du Petrole, Rueil Malmaison (France); Geffroy, F. [Centre de Geostatistique, Fontainebleau (France)] [and others


    The classical approach to construct reservoir models is to start with a fine scale geological model which is informed with petrophysical properties. Then scaling-up techniques allow to obtain a reservoir model which is compatible with the fluid flow simulators. Geostatistical modelling techniques are widely used to build the geological models before scaling-up. These methods provide equiprobable images of the area under investigation, which honor the well data, and which variability is the same than the variability computed from the data. At an appraisal phase, when few data are available, or when the wells are insufficient to describe all the heterogeneities and the behavior of the field, additional constraints are needed to obtain a more realistic geological model. For example, seismic data or stratigraphic models can provide average reservoir information with an excellent areal coverage, but with a poor vertical resolution. New advances in modelisation techniques allow now to integrate this type of additional external information in order to constrain the simulations. In particular, 2D or 3D seismic derived information grids, or sand-shale ratios maps coming from stratigraphic models can be used as external drifts to compute the geological image of the reservoir at the fine scale. Examples are presented to illustrate the use of these new tools, their impact on the final reservoir model, and their sensitivity to some key parameters.

  8. Constraints on geothermal reservoir volume change calculations from InSAR surface displacements and injection and production data (United States)

    Kaven, J. Ole; Barbour, Andrew J.; Ali, Tabrez


    Continual production of geothermal energy at times leads to significant surface displacement that can be observed in high spatial resolution using InSAR imagery. The surface displacement can be analyzed to resolve volume change within the reservoir revealing the often-complicated patterns of reservoir deformation. Simple point source models of reservoir deformation in a homogeneous elastic or poro-elastic medium can be superimposed to provide spatially varying, kinematic representations of reservoir deformation. In many cases, injection and production data are known in insufficient detail; but, when these are available, the same Green functions can be used to constrain the reservoir deformation. Here we outline how the injection and production data can be used to constrain bounds on the solution by posing the inversion as a quadratic programming with inequality constraints and regularization rather than a conventional least squares solution with regularization. We apply this method to InSAR-derived surface displacements at the Coso and Salton Sea Geothermal Fields in California, using publically available injection and production data. At both geothermal fields the available surface deformation in conjunction with the injection and production data permit robust solutions for the spatially varying reservoir deformation. The reservoir deformation pattern resulting from the constrained quadratic programming solution is more heterogeneous when compared to a conventional least squares solution. The increased heterogeneity is consistent with the known structural controls on heat and fluid transport in each geothermal reservoir.

  9. Effects of reservoirs water level variations on fish recruitment

    Directory of Open Access Journals (Sweden)

    Fabíula T. de Lima


    Full Text Available ABSTRACT The construction of hydroelectric power plants has many social and environmental impacts. Among them, the impacts on fish communities, which habitats are drastically modified by dams, with consequences across the ecosystem. This study aimed to assess the influence of water level (WL variations in the reservoirs of the Itá and Machadinho hydroelectric plants on the recruitment of fish species from the upper Uruguay River in southern Brazil. The data analyzed resulted from the WL variation produced exclusively by the hydroelectric plants generation and were collected between the years 2001 and 2012. The results showed significant correlations between the abundance of juvenile fish and the hydrological parameters only for some reproductive guilds. The species that spawn in nests showed, in general, a clear preference for the stability in the WL of the reservoirs, while the species that spawn in macrophytes or that release demersal eggs showed no significant correlation between the abundance of juvenile fish and hydrological parameters. A divergence of results between the two reservoirs was observed between the species that release semi-dense eggs; a positive correlation with a more stable WL was only observed in the Machadinho reservoir. This result can be driven by a wider range of WL variation in Machadinho reservoir.

  10. The perceived constraints, motivation, and physical activity levels of ...

    African Journals Online (AJOL)

    The purpose of this research was threefold; Are Korean youth physically active to promote health during leisure time? What constraints to physical active do youth experience during leisure time? Are there relationships among constraints, motivation, and physical activity level? Of 1 280 youth randomly selected by a ...

  11. Educational Level and Major Constraints Faced by Farmers and ...

    African Journals Online (AJOL)

    Educational Level and Major Constraints Faced by Farmers and Tappers in Production and Marketing of Coconut-based Products. ... Journal of Agriculture, Science and Technology ... The study identified all the major constraints that attributed to the amorphous marketing structures and lack of processing industries.

  12. Make use of dynamic data - a constraint based EnKF for SAGD reservoir characterization and production management

    Energy Technology Data Exchange (ETDEWEB)

    Gul, Ali; Nejadi, Siavash; Shah, Sirish L; Trivedi, Japan J [University of Alberta (Canada)


    Steam assisted gravity drainage (SAGD) is a thermal recovery process widely used in the Athabasca oil sands, the largest bitumen reservoir in the world. In order to optimize the process, an accurate characterization of the reservoir heterogeneity and identification of the potential steam barriers is necessary. The aim of this paper was to assess the potential of constraint based ensemble Kalman filter (EnKF) approach with localization to address these issues. Data records from observation, production and injection wells were used and the method was tested on a twin well SAGD process and a single well SAGD model with hybrid grids. Results showed a better characterization of the reservoir's heterogeneity and a reduction of uncertainty in the prediction of steam chamber growth. The technique developed herein provides accurate information about the steam chamber and the reservoir heterogeneity and can be used for planning and decision making of other field development strategies.

  13. Constraints on relaxation rates for N-level quantum systems

    International Nuclear Information System (INIS)

    Schirmer, S.G.; Solomon, A.I.


    We study the constraints imposed on the population and phase relaxation rates by the physical requirement of completely positive evolution for open N-level systems. The Lindblad operators that govern the evolution of the system are expressed in terms of observable relaxation rates, explicit formulas for the decoherence rates due to population relaxation are derived, and it is shown that there are additional, nontrivial constraints on the pure dephasing rates for N>2. Explicit, experimentally testable inequality constraints for the decoherence rates are derived for three- and four-level systems, and the implications of the results are discussed for generic ladder, Λ, and V systems and transitions between degenerate energy levels

  14. Quantification of Libby Reservoir Levels Needed to Maintain or Enhance Reservoir Fisheries, 1983-1987 Methods and Data Summary.

    Energy Technology Data Exchange (ETDEWEB)

    Chisholm, Ian


    Libby Reservoir was created under an International Columbia River Treaty between the United States and Canada for cooperative water development of the Columbia River Basin. The authorized purpose of the dam is to provide power, flood control, and navigation and other benefits. Research began in May 1983 to determine how operations of Libby dam impact the reservoir fishery and to suggest ways to lessen these impacts. This study is unique in that it was designed to accomplish its goal through detailed information gathering on every trophic level in the reservoir system and integration of this information into a quantitative computer model. The specific study objectives are to: quantify available reservoir habitat, determine abundance, growth and distribution of fish within the reservoir and potential recruitment of salmonids from Libby Reservoir tributaries within the United States, determine abundance and availability of food organisms for fish in the reservoir, quantify fish use of available food items, develop relationships between reservoir drawdown and reservoir habitat for fish and fish food organisms, and estimate impacts of reservoir operation on the reservoir fishery. 115 refs., 22 figs., 51 tabs.

  15. Level-Set Topology Optimization with Aeroelastic Constraints (United States)

    Dunning, Peter D.; Stanford, Bret K.; Kim, H. Alicia


    Level-set topology optimization is used to design a wing considering skin buckling under static aeroelastic trim loading, as well as dynamic aeroelastic stability (flutter). The level-set function is defined over the entire 3D volume of a transport aircraft wing box. Therefore, the approach is not limited by any predefined structure and can explore novel configurations. The Sequential Linear Programming (SLP) level-set method is used to solve the constrained optimization problems. The proposed method is demonstrated using three problems with mass, linear buckling and flutter objective and/or constraints. A constraint aggregation method is used to handle multiple buckling constraints in the wing skins. A continuous flutter constraint formulation is used to handle difficulties arising from discontinuities in the design space caused by a switching of the critical flutter mode.

  16. Lot Sizing Based on Stochastic Demand and Service Level Constraint

    Directory of Open Access Journals (Sweden)

    hajar shirneshan


    Full Text Available Considering its application, stochastic lot sizing is a significant subject in production planning. Also the concept of service level is more applicable than shortage cost from managers' viewpoint. In this paper, the stochastic multi period multi item capacitated lot sizing problem has been investigated considering service level constraint. First, the single item model has been developed considering service level and with no capacity constraint and then, it has been solved using dynamic programming algorithm and the optimal solution has been derived. Then the model has been generalized to multi item problem with capacity constraint. The stochastic multi period multi item capacitated lot sizing problem is NP-Hard, hence the model could not be solved by exact optimization approaches. Therefore, simulated annealing method has been applied for solving the problem. Finally, in order to evaluate the efficiency of the model, low level criterion has been used .

  17. Petroacoustic Modelling of Heterolithic Sandstone Reservoirs: A Novel Approach to Gassmann Modelling Incorporating Sedimentological Constraints and NMR Porosity data (United States)

    Matthews, S.; Lovell, M.; Davies, S. J.; Pritchard, T.; Sirju, C.; Abdelkarim, A.


    Heterolithic or 'shaly' sandstone reservoirs constitute a significant proportion of hydrocarbon resources. Petroacoustic models (a combination of petrophysics and rock physics) enhance the ability to extract reservoir properties from seismic data, providing a connection between seismic and fine-scale rock properties. By incorporating sedimentological observations these models can be better constrained and improved. Petroacoustic modelling is complicated by the unpredictable effects of clay minerals and clay-sized particles on geophysical properties. Such effects are responsible for erroneous results when models developed for "clean" reservoirs - such as Gassmann's equation (Gassmann, 1951) - are applied to heterolithic sandstone reservoirs. Gassmann's equation is arguably the most popular petroacoustic modelling technique in the hydrocarbon industry and is used to model elastic effects of changing reservoir fluid saturations. Successful implementation of Gassmann's equation requires well-constrained drained rock frame properties, which in heterolithic sandstones are heavily influenced by reservoir sedimentology, particularly clay distribution. The prevalent approach to categorising clay distribution is based on the Thomas - Stieber model (Thomas & Stieber, 1975), this approach is inconsistent with current understanding of 'shaly sand' sedimentology and omits properties such as sorting and grain size. The novel approach presented here demonstrates that characterising reservoir sedimentology constitutes an important modelling phase. As well as incorporating sedimentological constraints, this novel approach also aims to improve drained frame moduli estimates through more careful consideration of Gassmann's model assumptions and limitations. A key assumption of Gassmann's equation is a pore space in total communication with movable fluids. This assumption is often violated by conventional applications in heterolithic sandstone reservoirs where effective porosity, which

  18. Quantification of Hungry Horse Reservoir Water Levels Needed to Maintain or Enhance Reservoir Fisheries, 1983-1985 Summary Report.

    Energy Technology Data Exchange (ETDEWEB)

    May, Bruce


    The Pacific Northwest Electric Power Planning and Conservation Act passed in 1980 by Congress has provided a mechanism which integrates and provides for stable energy planning in the Pacific Northwest. The Act created the Northwest Power Planning Council and charged the Council with developing a comprehensive fish and wildlife program to protect and enhance fish and wildlife impacted by hydroelectric development in the Columbia River Basin. Implementation of the plan is being carried out by the Bonneville Power Administration. The Hungry Horse Reservoir study is part of that Council's plan. This study proposes to quantify seasonal water levels needed to maintain or enhance principal gamefish species in Hungry Horse Reservoir. The specific study objects are listed below. (1) Quantify the amount of reservoir habitat available at different water level elevations; (2) Estimate recruitment of westslope cutthroat trout juveniles from important spawning and nursery tributaries; (3) Determine the abundance, growth, distribution and use of available habitat by major game species in the reservoir; (4) Determine the abundance and availability of fish food organisms in the reservoir; (5) Quantify the seasonal use of available food items by major fish species; (6) Develop relationships between reservoir drawdown and reservoir habitat used by fish and fish food organisms; and (7) Estimate the impact of reservoir operation on major gamefish species.

  19. Quantification of Libby Reservoir Water Levels Needed to Maintain or Enhance Reservoir Fisheries, 1988-1996 Methods and Data Summary.

    Energy Technology Data Exchange (ETDEWEB)

    Dalbey, Steven Ray


    The Libby Reservoir study is part of the Northwest Power Planning Council's resident fish and wildlife program. The program was mandated by the Northwest Planning Act of 1980, and is responsible for mitigating for damages to fish and wildlife caused by hydroelectric development in the Columbia River Basin. The objective of Phase I of the project (1983 through 1987) was to maintain or enhance the Libby Reservoir fishery by quantifying seasonal water levels and developing ecologically sound operational guidelines. The objective of Phase II of the project (1988 through 1996) was to determine the biological effects of reservoir operations combined with biotic changes associated with an aging reservoir. This report summarizes the data collected from Libby Reservoir during 1988 through 1996.

  20. Detection of a reservoir water level using shape similarity metrics (United States)

    Pipitone, Claudia; Maltese, Antonino; Dardanelli, Gino; Capodici, Fulvio; Lo Brutto, Mauro; La Loggia, Goffredo


    The matching between reservoirs' water edge and digital elevation model's (DEM) contour lines allowed determining the water level at the acquisition date of satellite images. A preliminary study was conducted on the Castello dam (Magazzolo Lake), between Alessandria della Rocca and Bivona (Agrigento, south-Italy). The accuracy assessment of the technique was than evaluated from the comparison between classified and reference objects using similarity metrics about the shape, theme, edge and position, through the plugin STEP of open source software GIS. Moreover, an independent GIS technique was implemented to evaluate the water level, based on a distances' array between existing contour lines and nodes extracted from vectorised classification images. Results have shown the potentiality of the techniques when applied on an ideal case; advantages and disadvantages when the images are characterized by clear sky, and limits when images are acquired during not ideal atmospheric conditions.

  1. The Coupling Effect of Rainfall and Reservoir Water Level Decline on the Baijiabao Landslide in the Three Gorges Reservoir Area, China

    Directory of Open Access Journals (Sweden)

    Nenghao Zhao


    Full Text Available Rainfall and reservoir level fluctuation are two of the main factors contributing to reservoir landslides. However, in China’s Three Gorges Reservoir Area, when the reservoir water level fluctuates significantly, it comes at a time of abundant rainfall, which makes it difficult to distinguish which factor dominates the deformation of the landslide. This study focuses on how rainfall and reservoir water level decline affect the seepage and displacement field of Baijiabao landslide spatially and temporally during drawdown of reservoir water level in the Three Gorges Reservoir Area, thus exploring its movement mechanism. The monitoring data of the landslide in the past 10 years were analyzed, and the correlation between rainfall, reservoir water level decline, and landslide displacement was clarified. By the numerical simulation method, the deformation evolution mechanism of this landslide during drawdown of reservoir water level was revealed, respectively, under three conditions, namely, rainfall, reservoir water level decline, and coupling of the above two conditions. The results showed that the deformation of the Baijiabao landslide was the coupling effect of rainfall and reservoir water level decline, while the latter effect is more pronounced.

  2. Vandenberg Air Force Base Upper Level Wind Launch Weather Constraints (United States)

    Shafer, Jaclyn A.; Wheeler, Mark M.


    The 30th Operational Support Squadron Weather Flight (30 OSSWF) provides comprehensive weather services to the space program at Vandenberg Air Force Base (VAFB) in California. One of their responsibilities is to monitor upper-level winds to ensure safe launch operations of the Minuteman III ballistic missile. The 30 OSSWF tasked the Applied Meteorology Unit (AMU) to analyze VAFB sounding data with the goal of determining the probability of violating (PoV) their upper-level thresholds for wind speed and shear constraints specific to this launch vehicle, and to develop a tool that will calculate the PoV of each constraint on the day of launch. In order to calculate the probability of exceeding each constraint, the AMU collected and analyzed historical data from VAFB. The historical sounding data were retrieved from the National Oceanic and Atmospheric Administration Earth System Research Laboratory archive for the years 1994-2011 and then stratified into four sub-seasons: January-March, April-June, July-September, and October-December. The maximum wind speed and 1000-ft shear values for each sounding in each subseason were determined. To accurately calculate the PoV, the AMU determined the theoretical distributions that best fit the maximum wind speed and maximum shear datasets. Ultimately it was discovered that the maximum wind speeds follow a Gaussian distribution while the maximum shear values follow a lognormal distribution. These results were applied when calculating the averages and standard deviations needed for the historical and real-time PoV calculations. In addition to the requirements outlined in the original task plan, the AMU also included forecast sounding data from the Rapid Refresh model. This information provides further insight for the launch weather officers (LWOs) when determining if a wind constraint violation will occur over the next few hours on day of launch. The interactive graphical user interface (GUI) for this project was developed in

  3. Development of a new control device for stabilizing blood level in reservoir during extracorporeal circulation. (United States)

    Momose, Naoki; Yamakoshi, Rie; Kokubo, Ryo; Yasuda, Toru; Iwamoto, Norio; Umeda, Chinori; Nakajima, Itsuro; Yanagisawa, Mitsunobu; Tomizawa, Yasuko


    We developed a simple device that stabilizes the blood level in the reservoir of the extracorporeal circulation open circuit system by measuring the hydrostatic pressure of the reservoir to control the flow rate of the arterial pump. When the flow rate of the venous return decreases, the rotation speed of the arterial pump is automatically slowed down. Consequently, the blood level in the reservoir is stabilized quickly between two arbitrarily set levels and never falls below the pre-set low level. We conducted a basic experiment to verify the operation of the device, using a mock circuit with water. Commercially available pumps and reservoir were used without modification. The results confirmed that the control method effectively regulates the reservoir liquid level and is highly reliable. The device possibly also functions as a safety device.

  4. Constraint-based deadlock checking of high-level specifications

    DEFF Research Database (Denmark)

    Hallerstede, Stefan; Leuschel, Michael


    B's Prolog kernel, such as reification of membership and arithmetic constraints. ProB typically finds counter examples to deadlock-freedom constraints, a formula of about 900 partly nested conjunctions and disjunction among them 80 arithmetic and 150 set-theoretic predicates (in total a formula of 30 pages....... In this paper we propose a constraint-based approach to finding deadlocks employing the ProB constraint solver to find values for the constants and variables of formal models that describe a deadlocking state. We present the general technique, as well as various improvements that had to be performed on Pro......), in under two seconds. We also present other successful applications of this new technique, in particular to BPEL processes. Experiments using SAT and SMT solvers on these constraints were thus far unsuccessful....

  5. Sediment transport in the aftermath of the 2008 Wenchuan earthquake: constraints from landslide mapping, photo-sieving and reservoir accumulation (United States)

    Li, G.; West, A. J.; Hammond, D. E.; Xiao, Z.; Okaya, D. A.; Densmore, A. L.; Hilton, R. G.; Jin, Z.; Zhang, F.; Wang, J.


    Understanding post-seismic sediment transport is important for assessing crustal mass redistribution by earthquakes and for managing seismically-induced geohazards, including channel aggradation and flooding. The 2008 Wenchuan earthquake (Mw 7.9) triggered over 60,000 landslides in the Longmen Shan range of the eastern Tibetan Plateau. Records from hydrometric gauging show enhanced regional suspended sediment fluxes following the earthquake, resulting from evacuation of the landslide sediment (Wang et al., in revision). In addition to the insights into suspended sediment dynamics from gauging stations, this large-magnitude seismic event provides an opportunity to study bedload sediment transport after a large earthquake. Here we present primary results from a comprehensive investigation of the Min Jiang river system following the Wenchuan earthquake. Using a landslide inventory map (Li et al., 2014) and a DEM-based river network, we mapped landslide-river network connectivity. With photo-sieving techniques, we estimated the grain size distribution of medium-grained (mm to cm scale) landslide deposits. These data provide constraints on sediment sources. The mass of sediment in transport has been estimated from river sediment quartz 10Be measurements (West et al., 2014), supplemented here by constraints from rates of sediment infill in a downstream reservoir, determined by bathymetric profiling and analysis of sediment cores. Together with hydrometric data, this dataset provides the basic parameters for modeling sediment transport in the Min Jiang river system after the Wenchuan earthquake and promises insight into the mechanisms controlling post-earthquake sediment transport. References Li et al., 2014 , Geochem. Geophys. Geosyst., 15, 833-844, Wang et al., in revision West et al., 2014, Earth Planet Sc. Lett., 396, 143-153

  6. Water-level fluctuations influence sediment porewater chemistry and methylmercury production in a flood-control reservoir. (United States)

    Reservoirs typically have elevated fish mercury (Hg) levels compared to natural lakes and rivers. A unique feature of reservoirs is water-level management which can result in sediment exposure to the air. The objective of this study is to identify how reservoir water-level fluct...

  7. Response of littoral macrophytes to water level fluctuations in a storage reservoir

    Directory of Open Access Journals (Sweden)

    Krolová M.


    Full Text Available Lakes and reservoirs that are used for water supply and/or flow regulations have usually poorly developed littoral macrophyte communities, which impairs ecological potential in terms of the EU Water Framework Directive. The aim of our study was to reveal controlling factors for the growth of littoral macrophytes in a storage reservoir with fluctuating water level (Lipno Reservoir, Czech Republic. Macrophytes occurred in this reservoir only in the eulittoral zone i.e., the shoreline region between the highest and the lowest seasonal water levels. Three eulittoral sub-zones could be distinguished: the upper eulittoral with a stable community of perennial species with high cover, the middle eulittoral with relatively high richness of emergent and amphibious species present at low cover values, and the lower eulittoral devoid of permanent vegetation. Cover and species composition in particular sub-zones were primarily influenced by the duration and timing of flooding, followed by nutrient limitation and strongly reducing conditions in the flooded organic sediment. Our results stress the ecological importance of eulittoral zone in reservoirs with fluctuating water levels where macrophyte growth can be supported by targeted management of water level, thus helping reservoir managers in improving the ecological potential of this type of water bodies.

  8. Non-Markovian decay of a three-level cascade atom in a structured reservoir

    International Nuclear Information System (INIS)

    Dalton, B.J.; Garraway, B.M.


    The dynamics of a three-level atom in a cascade (or ladder) configuration with both transitions coupled to a single structured reservoir of quantized electromagnetic field modes is treated using Laplace transform methods applied to the coupled amplitude equations. In this system two-photon excitation of the reservoir occurs, and both sequences for emitting the two photons are allowed and included in the theory. An integral equation is found to govern the complex amplitudes of interest. It is shown that the dynamics of the atomic system is completely determined in terms of reservoir structure functions, which are products of the mode density with the coupling constant squared. This dependence on reservoir structure functions rather than on the mode density or coupling constants alone, shows that it may be possible to extend pseudomode theory to treat multiphoton excitation of a structured reservoir--pseudomodes being introduced in one-one correspondence with the poles of reservoir structure functions in the complex frequency plane. A general numerical method for solving the integral equations based on discretizing frequency space, and applicable to different structured reservoirs such as high-Q cavities and photonic band-gap systems, is presented. An application to a high-Q-cavity case with identical Lorentzian reservoir structure functions is made, and the non-Markovian decay of the excited state shown. A formal solution to the integral equations in terms of right and left eigenfunctions of a non-Hermitian kernel is also given. The dynamics of the cascade atom, with the two transitions coupled to two separate structured reservoirs of quantized electromagnetic field modes, is treated similarly to the single structured reservoir situation. Again the dynamics only depends on reservoir structure functions. As only one sequence of emitting the two photons now occurs, the integral equation for the amplitudes can be solved analytically. The non-Markovian decay of the

  9. Household‐level credit constraints in urban Ethiopia | Kedir ...

    African Journals Online (AJOL)

    We find a high percentage of credit‐constrained households. After controlling for potential endogeneity and selectivity bias, our econometric models showed that current household resources, number of dependants and location are significant correlates of credit constraints. Further, we discuss the policy implications of our ...

  10. Constraints on Water Reservoir Lifetimes From Catchment-Wide 10Be Erosion Rates—A Case Study From Western Turkey (United States)

    Heineke, Caroline; Hetzel, Ralf; Akal, Cüneyt; Christl, Marcus


    The functionality and retention capacity of water reservoirs is generally impaired by upstream erosion and reservoir sedimentation, making a reliable assessment of erosion indispensable to estimate reservoir lifetimes. Widely used river gauging methods may underestimate sediment yield, because they do not record rare, high-magnitude events and may underestimate bed load transport. Hence, reservoir lifetimes calculated from short-term erosion rates should be regarded as maximum values. We propose that erosion rates from cosmogenic 10Be, which commonly integrate over hundreds to thousands of years, are useful to complement short-term sediment yield estimates and should be employed to estimate minimum reservoir lifetimes. Here we present 10Be erosion rates for the drainage basins of six water reservoirs in Western Turkey, which are located in a tectonically active region with easily erodible bedrock. Our 10Be erosion rates for these catchments are high, ranging from ˜170 to ˜1,040 t/km2/yr. When linked to reservoir volumes, they yield minimum reservoir lifetimes between 25 ± 5 and 1,650 ± 360 years until complete filling, with four reservoirs having minimum lifespans of ≤110 years. In a neighboring region with more resistant bedrock and less tectonic activity, we obtain much lower catchment-wide 10Be erosion rates of ˜33 to ˜95 t/km2/yr, illustrating that differences in lithology and tectonic boundary conditions can cause substantial variations in erosion even at a spatial scale of only ˜50 km. In conclusion, we suggest that both short-term sediment yield estimates and 10Be erosion rates should be employed to predict the lifetimes of reservoirs.

  11. The effect of constraint level on a crack path

    Czech Academy of Sciences Publication Activity Database

    Ševčík, Martin; Hutař, Pavel; Náhlík, Luboš; Seitl, Stanislav


    Roč. 29, APR (2013), s. 83-92 ISSN 1350-6307. [Crack paths 2012. Gaeta, 19.09.2012-21.09.2012] R&D Projects: GA ČR GA106/09/1954; GA MŠk(CZ) ED1.1.00/02.0068; GA MŠk EE2.3.30.0063 Grant - others:Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M100420901 Institutional support: RVO:68081723 Keywords : Fracture mechanics * Constraint effect * Crack propagation * MTS criterion * Gear rim Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 1.130, year: 2013

  12. Increasing the predictive power of geostatistical reservoir models by integration of geological constraints from stratigraphic forward modeling

    NARCIS (Netherlands)

    Sacchi, Q.; Borello, E.S.; Weltje, G.J.; Dalman, R.


    Current static reservoir models are created by quantitative integration of interpreted well and seismic data through geostatistical tools. In these models, equiprobable realizations of structural settings and property distributions can be generated by stochastic simulation techniques. The

  13. Estimating the Optimal Capacity for Reservoir Dam based on Reliability Level for Meeting Demands

    Directory of Open Access Journals (Sweden)

    Mehrdad Taghian


    Full Text Available Introduction: One of the practical and classic problems in the water resource studies is estimation of the optimal reservoir capacity to satisfy demands. However, full supplying demands for total periods need a very high dam to supply demands during severe drought conditions. That means a major part of reservoir capacity and costs is only usable for a short period of the reservoir lifetime, which would be unjustified in economic analysis. Thus, in the proposed method and model, the full meeting demand is only possible for a percent time of the statistical period that is according to reliability constraint. In the general methods, although this concept apparently seems simple, there is a necessity to add binary variables for meeting or not meeting demands in the linear programming model structures. Thus, with many binary variables, solving the problem will be time consuming and difficult. Another way to solve the problem is the application of the yield model. This model includes some simpler assumptions and that is so difficult to consider details of the water resource system. The applicationof evolutionary algorithms, for the problems have many constraints, is also very complicated. Therefore, this study pursues another solution. Materials and Methods: In this study, for development and improvement the usual methods, instead of mix integer linear programming (MILP and the above methods, a simulation model including flow network linear programming is used coupled with an interface manual code in Matlab to account the reliability based on output file of the simulation model. The acre reservoir simulation program (ARSP has been utilized as a simulation model. A major advantage of the ARSP is its inherent flexibility in defining the operating policies through a penalty structure specified by the user. The ARSP utilizes network flow optimization techniques to handle a subset of general linear programming (LP problems for individual time intervals

  14. Water level influences on body condition of Geophagus brasiliensis (Perciformes: Cichlidae in a Brazilian oligotrophic reservoir

    Directory of Open Access Journals (Sweden)

    Alejandra Filippo Gonzalez Neves dos Santos

    Full Text Available Effects of water level fluctuations on body condition of Geophagus brasiliensis were studied in a 30 km² Brazilian oligotrophic reservoir. Physiological condition (K and gonadosomatic index (GSI were compared according to water level (low and high. Females' best conditions were associated to higher resources availability during high water, since gonad development did not change between low and high water. Males' condition did not change between water levels, while the highest gonad development occurred in low water. Females presented higher reproductive investment than males, which allocated most of energy for somatic development. This strategy could be a mechanism to undergo the stress caused by oligotrophic characteristics of the reservoir enhanced during low water level.

  15. A framework to identify Pareto-efficient subdaily environmental flow constraints on hydropower reservoirs using a grid-wide power dispatch model (United States)

    Olivares, Marcelo A.; Haas, Jannik; Palma-Behnke, Rodrigo; Benavides, Carlos


    Hydrologic alteration due to hydropeaking reservoir operations is a main concern worldwide. Subdaily environmental flow constraints (ECs) on operations can be promising alternatives for mitigating negative impacts. However, those constraints reduce the flexibility of hydropower plants, potentially with higher costs for the power system. To study the economic and environmental efficiency of ECs, this work proposes a novel framework comprising four steps: (i) assessment of the current subdaily hydrologic alteration; (ii) formulation and implementation of a short-term, grid-wide hydrothermal coordination model; (iii) design of ECs in the form of maximum ramping rates (MRRs) and minimum flows (MIFs) for selected hydropower reservoirs; and (iv) identification of Pareto-efficient solutions in terms of grid-wide costs and the Richard-Baker flashiness index for subdaily hydrologic alteration (SDHA). The framework was applied to Chile's main power grid, assessing 25 EC cases, involving five MIFs and five MRRs. Each case was run for a dry, normal, and wet water year type. Three Pareto-efficient ECs are found, with remarkably small cost increase below 2% and a SDHA improvement between 28% and 90%. While the case involving the highest MIF worsens the flashiness of another basin, the other two have no negative effect on other basins and can be recommended for implementation.


    Directory of Open Access Journals (Sweden)

    Lori Badea


    Full Text Available In this paper we introduce four multigrid algorithms for the constrained minimization of non-quadratic functionals. These algorithms are combinations of additive or multiplicative iterations on levels with additive or multiplicative ones over the levels. The convex set is decomposed as a sum of convex level subsets, and consequently, the algorithms have an optimal computing complexity. The methods are described as multigrid V -cycles, but the results hold for other iteration types, the W-cycle iterations, for instance. We estimate the global convergence rates of the proposed algorithms as functions of the number of levels, and compare them with the convergence rates of other existing multigrid methods. Even if the general convergence theory olds for convex sets which can be decomposed as a sum of convex level subsets, our algorithms are applied to the one-obstacle problems because, for these problems, we are able to construct optimal decompositions. But, in this case, the convergence rates of the methods introduced in this paper are better than those of the methods we know in the literature.

  17. High-Level Synthesis: Productivity, Performance, and Software Constraints

    Directory of Open Access Journals (Sweden)

    Yun Liang


    Full Text Available FPGAs are an attractive platform for applications with high computation demand and low energy consumption requirements. However, design effort for FPGA implementations remains high—often an order of magnitude larger than design effort using high-level languages. Instead of this time-consuming process, high-level synthesis (HLS tools generate hardware implementations from algorithm descriptions in languages such as C/C++ and SystemC. Such tools reduce design effort: high-level descriptions are more compact and less error prone. HLS tools promise hardware development abstracted from software designer knowledge of the implementation platform. In this paper, we present an unbiased study of the performance, usability and productivity of HLS using AutoPilot (a state-of-the-art HLS tool. In particular, we first evaluate AutoPilot using the popular embedded benchmark kernels. Then, to evaluate the suitability of HLS on real-world applications, we perform a case study of stereo matching, an active area of computer vision research that uses techniques also common for image denoising, image retrieval, feature matching, and face recognition. Based on our study, we provide insights on current limitations of mapping general-purpose software to hardware using HLS and some future directions for HLS tool development. We also offer several guidelines for hardware-friendly software design. For popular embedded benchmark kernels, the designs produced by HLS achieve 4X to 126X speedup over the software version. The stereo matching algorithms achieve between 3.5X and 67.9X speedup over software (but still less than manual RTL design with a fivefold reduction in design effort versus manual RTL design.

  18. Lava lake level as a gauge of magma reservoir pressure and eruptive hazard (United States)

    Patrick, Matthew R.; Anderson, Kyle R.; Poland, Michael P.; Orr, Tim R.; Swanson, Donald A.


    Forecasting volcanic activity relies fundamentally on tracking magma pressure through the use of proxies, such as ground surface deformation and earthquake rates. Lava lakes at open-vent basaltic volcanoes provide a window into the uppermost magma system for gauging reservoir pressure changes more directly. At Kīlauea Volcano (Hawaiʻi, USA) the surface height of the summit lava lake in Halemaʻumaʻu Crater fluctuates with surface deformation over short (hours to days) and long (weeks to months) time scales. This correlation implies that the lake behaves as a simple piezometer of the subsurface magma reservoir. Changes in lava level and summit deformation scale with (and shortly precede) changes in eruption rate from Kīlauea's East Rift Zone, indicating that summit lava level can be used for short-term forecasting of rift zone activity and associated hazards at Kīlauea.

  19. Dynamics of quantum Fisher information in a two-level system coupled to multiple bosonic reservoirs (United States)

    Wang, Guo-You; Guo, You-Neng; Zeng, Ke


    We consider the optimal parameter estimation for a two-level system coupled to multiple bosonic reservoirs. By using quantum Fisher information (QFI), we investigate the effect of the Markovian reservoirs’ number N on QFI in both weak and strong coupling regimes for a two-level system surrounded by N zero-temperature reservoirs of field modes initially in the vacua. The results show that the dynamics of QFI non-monotonically decays to zero with revival oscillations at some time in the weak coupling regime depending on the reservoirs’ parameters. Furthermore, we also present the relations between the QFI flow, the flows of energy and information, and the sign of the decay rate to gain insight into the physical processes characterizing the dynamics. Project supported by the Hunan Provincial Innovation Foundation for Postgraduate, China (Grant No. CX2014B194) and the Scientific Research Foundation of Hunan Provincial Education Department, China (Grant No. 13C039).

  20. System-level modeling for economic evaluation of geological CO2 storage in gas reservoirs

    International Nuclear Information System (INIS)

    Zhang, Yingqi; Oldenburg, Curtis M.; Finsterle, Stefan; Bodvarsson, Gudmundur S.


    One way to reduce the effects of anthropogenic greenhouse gases on climate is to inject carbon dioxide (CO 2 ) from industrial sources into deep geological formations such as brine aquifers or depleted oil or gas reservoirs. Research is being conducted to improve understanding of factors affecting particular aspects of geological CO 2 storage (such as storage performance, storage capacity, and health, safety and environmental (HSE) issues) as well as to lower the cost of CO 2 capture and related processes. However, there has been less emphasis to date on system-level analyses of geological CO 2 storage that consider geological, economic, and environmental issues by linking detailed process models to representations of engineering components and associated economic models. The objective of this study is to develop a system-level model for geological CO 2 storage, including CO 2 capture and separation, compression, pipeline transportation to the storage site, and CO 2 injection. Within our system model we are incorporating detailed reservoir simulations of CO 2 injection into a gas reservoir and related enhanced production of methane. Potential leakage and associated environmental impacts are also considered. The platform for the system-level model is GoldSim [GoldSim User's Guide. GoldSim Technology Group; 2006,]. The application of the system model focuses on evaluating the feasibility of carbon sequestration with enhanced gas recovery (CSEGR) in the Rio Vista region of California. The reservoir simulations are performed using a special module of the TOUGH2 simulator, EOS7C, for multicomponent gas mixtures of methane and CO 2 . Using a system-level modeling approach, the economic benefits of enhanced gas recovery can be directly weighed against the costs and benefits of CO 2 injection

  1. Porosity and permeability evolution of vesicular basalt reservoirs with increasing depth: constraints from the Big Island of Hawai'i (United States)

    Millett, John; Haskins, Eric; Thomas, Donald; Jerram, Dougal; Planke, Sverre; Healy, Dave; Kück, Jochem; Rossetti, Lucas; Farrell, Natalie; Pierdominici, Simona


    Volcanic reservoirs are becoming increasingly important in the targeting of petroleum, geothermal and water resources globally. However, key areas of uncertainty in relation to volcanic reservoir properties during burial in different settings remain. In this contribution, we present results from borehole logging and sampling operations within two fully cored c. 1.5 km deep boreholes, PTA2 and KMA1, from the Humúula saddle region on the Big Island of Hawai'i. The boreholes were drilled as part of the Humu'ula Groundwater Research Project (HGRP) between 2013-2016 and provide unique insights into the evolution of pore structure with increasing burial in a basaltic dominated lava sequence. The boreholes encounter mixed sequences of 'a'ā, pāhoehoe and transitional lava flows along with subsidiary intrusions and sediments from the shield to post-shield phases of Mauna Kea. Borehole wireline data including sonic, spectral gamma and Televiewer imagery were collected along with density, porosity, permeability and ultrasonic velocity laboratory measurements from core samples. A range of intra-facies were sampled for analysis from various depths within the two boreholes. By comparison with core data, the potential for high resolution Televiewer imaging to reveal spectacular intra-facies features including individual vesicles, vesicle segregations, 'a'ā rubble zones, intrusive contacts, and intricate pāhoehoe lava flow lobe morphologies is demonstrated. High quality core data enables the calibration of Televiewer facies enabling improved interpretation of volcanic reservoir features in the more common exploration scenario where core is absent. Laboratory results record the ability of natural vesicular basalt samples to host very high porosity (>50%) and permeability (>10 darcies) within lava flow top facies which we demonstrate are associated with vesicle coalescence and not micro-fractures. These properties may be maintained to depths of c. 1.5 km in regions of limited

  2. Spontaneous emission spectrum of a four-level atom coupled by three kinds of reservoirs

    International Nuclear Information System (INIS)

    Yang Dong; Wang Jian; Zhang, Hanzhuang; Yao Jinbo


    A model of a four-level atom embedded in a double-band photonic crystal (PC) is presented. The atomic transitions from the upper two levels to the lower two levels are coupled by the same reservoir which is assumed in turn to be isotropic PC modes, anisotropic PC modes and free vacuum modes. The effects of the fine structure of the atomic ground state levels and the quantum interference on the spontaneous emission spectrum of an atom are investigated in detail. Most interestingly, it is shown for the first time that new spontaneous emission lines are produced from the fine splitting of atomic ground state levels in the isotropic PC case. Quantum interference induces additional narrow spontaneous lines near the transition from the empty upper level to the lower levels

  3. Simulation of extreme reservoir level distribution with the SCHADEX method (EXTRAFLO project) (United States)

    Paquet, Emmanuel; Penot, David; Garavaglia, Federico


    The standard practice for the design of dam spillways structures and gates is to consider the maximum reservoir level reached for a given hydrologic scenario. This scenario has several components: peak discharge, flood volumes on different durations, discharge gradients etc. Within a probabilistic analysis framework, several scenarios can be associated with different return times, although a reference return level (e.g. 1000 years) is often prescribed by the local regulation rules or usual practice. Using continuous simulation method for extreme flood estimation is a convenient solution to provide a great variety of hydrological scenarios to feed a hydraulic model of dam operation: flood hydrographs are explicitly simulated by a rainfall-runoff model fed by a stochastic rainfall generator. The maximum reservoir level reached will be conditioned by the scale and the dynamics of the generated hydrograph, by the filling of the reservoir prior to the flood, and by the dam gates and spillway operation during the event. The simulation of a great number of floods will allow building a probabilistic distribution of maximum reservoir levels. A design value can be chosen at a definite return level. An alternative approach is proposed here, based on the SCHADEX method for extreme flood estimation, proposed by Paquet et al. (2006, 2013). SCHADEX is a so-called "semi-continuous" stochastic simulation method in that flood events are simulated on an event basis and are superimposed on a continuous simulation of the catchment saturation hazard using rainfall-runoff modelling. The SCHADEX process works at the study time-step (e.g. daily), and the peak flow distribution is deduced from the simulated daily flow distribution by a peak-to-volume ratio. A reference hydrograph relevant for extreme floods is proposed. In the standard version of the method, both the peak-to-volume and the reference hydrograph are constant. An enhancement of this method is presented, with variable peak

  4. Quantification of Libby Reservoir Levels Needed to Maintain or Enhance Reservior Fisheries, 1984 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Shepard, Bradley B.


    We are evaluating the potential impacts of Libby Reservoir operation on the fishery in Libby Reservoir. The sampling program has been tested and modified to provide data for developing an understanding of how reservoir operation impacts the reservoir fishery. Temperature appears to be an important variable influenced by reservoir operation which regulates fish and fish food production and distribution. 39 refs., 21 figs., 19 tabs.

  5. Reservoir stratification affects methylmercury levels in river water, plankton, and fish downstream from Balbina hydroelectric dam, Amazonas, Brazil. (United States)

    Kasper, Daniele; Forsberg, Bruce R; Amaral, João H F; Leitão, Rafael P; Py-Daniel, Sarah S; Bastos, Wanderley R; Malm, Olaf


    The river downstream from a dam can be more contaminated by mercury than the reservoir itself. However, it is not clear how far the contamination occurs downstream. We investigated the seasonal variation of methylmercury levels in the Balbina reservoir and how they correlated with the levels encountered downstream from the dam. Water, plankton, and fishes were collected upstream and at sites between 0.5 and 250 km downstream from the dam during four expeditions in 2011 and 2012. Variations in thermal stratification of the reservoir influenced the methylmercury levels in the reservoir and in the river downstream. Uniform depth distributions of methylmercury and oxygen encountered in the poorly stratified reservoir during the rainy season collections coincided with uniformly low methylmercury levels along the river downstream from the dam. During dry season collections, the reservoir was strongly stratified, and anoxic hypolimnion water with high methylmercury levels was exported downstream. Methylmercury levels declined gradually to 200 km downstream. In general, the methylmercury levels in plankton and fishes downstream from the dam were higher than those upstream. Higher methylmercury levels observed 200-250 km downstream from the dam during flooding season campaigns may reflect the greater inflow from tributaries and flooding of natural wetlands that occurred at this time.

  6. Influence of Large Reservoir Operation on Water-Levels and Flows in Reaches below Dam: Case Study of the Three Gorges Reservoir. (United States)

    Yang, Yunping; Zhang, Mingjin; Zhu, Lingling; Liu, Wanli; Han, Jianqiao; Yang, Yanhua


    The Three Gorges Project (TGP) is the world's largest water conservation project. The post-construction low-flow water level at the same discharge below the dam has declined, but there remains disagreement over whether the flood level has increased. Measured water levels and upstream and downstream flow data from 1955 to 2016 show that, post-construction: (1) the low-flow water level at the same discharge decreased, and the lowest water level increased due to dry-season reservoir discharge; (2) the decline of the low-flow water level below the dam was less than the undercutting value of the flow channel of the river; (3) the flood level at the same discharge below the dam was slightly elevated, although peak water levels decreased; (4) flood characteristics changed from a high discharge-high flood level to a medium discharge - high flood level; and (5) an expected decline in the flood level downstream was not observed. Channel erosion and the adjustment of rivers and lakes tend to reduce flood levels, while river bed coarsening, vegetation, and human activities downstream increase the flood level. Although the flood control benefits of the Three Gorges Dam (TGD) and the upstream reservoirs are obvious, increased elevation of the downstream flood level remains a concern.

  7. Stability Analysis of Hydrodynamic Pressure Landslides with Different Permeability Coefficients Affected by Reservoir Water Level Fluctuations and Rainstorms

    Directory of Open Access Journals (Sweden)

    Faming Huang


    Full Text Available It is significant to study the variations in the stability coefficients of hydrodynamic pressure landslides with different permeability coefficients affected by reservoir water level fluctuations and rainstorms. The Sifangbei landslide in Three Gorges Reservoir area is used as case study. Its stability coefficients are simulated based on saturated-unsaturated seepage theory and finite element analysis. The operating conditions of stability coefficients calculation are reservoir water level variations between 175 m and 145 m, different rates of reservoir water level fluctuations, and a three-day continuous rainstorm. Results show that the stability coefficient of the hydrodynamic pressure landslide decreases with the drawdown of the reservoir water level, and a rapid drawdown rate leads to a small stability coefficient when the permeability coefficient ranges from 1.16 × 10−6 m/s to 4.64 × 10−5 m/s. Additionally, the landslide stability coefficient increases as the reservoir water level increases, and a rapid increase in the water level leads to a high stability coefficient when the permeability coefficient ranges from 1.16 × 10−6 m/s to 4.64 × 10−5 m/s. The landslide stability coefficient initially decreases and then increases as the reservoir water level declines when the permeability coefficient is greater than 4.64 × 10−5 m/s. Moreover, for structures with the same landslide, the landslide stability coefficient is most sensitive to the change in the rate of reservoir water level drawdown when the permeability coefficient increases from 1.16 × 10−6 m/s to 1.16 × 10−4 m/s. Additionally, the rate of decrease in the stability coefficient increases as the permeability coefficient increases. Finally, the three-day rainstorm leads to a significant reduction in landslide stability, and the rate of decrease in the stability coefficient initially increases and then decreases as the permeability coefficient increases.

  8. Automated Liquid-Level Control of a Nutrient Reservoir for a Hydroponic System (United States)

    Smith, Boris; Asumadu, Johnson A.; Dogan, Numan S.


    A microprocessor-based system for control of the liquid level of a nutrient reservoir for a plant hydroponic growing system has been developed. The system uses an ultrasonic transducer to sense the liquid level or height. A National Instruments' Multifunction Analog and Digital Input/Output PC Kit includes NI-DAQ DOS/Windows driver software for an IBM 486 personal computer. A Labview Full Development system for Windows is the graphical programming system being used. The system allows liquid level control to within 0.1 cm for all levels tried between 8 and 36 cm in the hydroponic system application. The detailed algorithms have been developed and a fully automated microprocessor based nutrient replenishment system has been described for this hydroponic system.

  9. Aeroelastic two-level optimization for preliminary design of wing structures considering robust constraints

    Directory of Open Access Journals (Sweden)

    Wan Zhiqiang


    Full Text Available An aeroelastic two-level optimization methodology for preliminary design of wing structures is presented, in which the parameters for structural layout and sizes are taken as design variables in the first-level optimization, and robust constraints in conjunction with conventional aeroelastic constraints are considered in the second-level optimization. A low-order panel method is used for aerodynamic analysis in the first-level optimization, and a high-order panel method is employed in the second-level optimization. It is concluded that the design of the abovementioned structural parameters of a wing can be improved using the present method with high efficiency. An improvement is seen in aeroelastic performance of the wing obtained with the present method when compared to the initial wing. Since these optimized structures are obtained after consideration of aerodynamic and structural uncertainties, they are well suited to encounter these uncertainties when they occur in reality.

  10. The effect of service level constraint on EPQ model with random defective rate

    Directory of Open Access Journals (Sweden)


    Full Text Available We study the effect of service level constraint on the economic production quantity (EPQ model with random defective rate. We first prove that the expected overall cost for imperfect quality EPQ model with backlogging permitted is less than or equal to that of the same model without backlogging. Secondly, the relationship between “imputed backorder cost” and maximal shortage level is derived for decision-making on whether the required service level is achievable. Then an equation is proposed for calculating the intangible backorder cost for the situation when the required service level is not attainable. By including this intangible backorder cost in the mathematical analysis, one can derive a new optimal lot-size policy that minimizes expected total costs as well as satisfies the service level constraint. Numerical example is provided to demonstrate its practical usage.

  11. Mercury distribution in different tissues and trophic levels of fish from a tropical reservoir, Brazil

    Directory of Open Access Journals (Sweden)

    Daniele Kasper

    Full Text Available Concentrations of organic (OrgHg and inorganic mercury (InorgHg were assessed in different fish tissues (liver, muscle, kidney, gut and gonads and trophic levels collected in an impacted tropical reservoir in southeastern Brazil. Organic mercury concentrations in muscle were remarkably higher in the carnivorous species Hoplias malabaricus and Oligosarcus hepsetus. The ratios of OrgHg in relation to total mercury (%OrgHg in muscle also varied according to the species trophic level: 93% for carnivores, 84% for omnivores, 73% for algivores/planktivores and 58% for detritivores. The %OrgHg in the gut tissue of carnivores (78% was much higher than that found in omnivores (30%, possibly reflecting a process of trophic biomagnification in the reservoir. On the other hand, the InorgHg concentrations in muscle decreased with the trophic level increase, suggesting that this form of mercury did not biomagnify through the food web. Gonads contained the least total mercury, and approximately all of this mercury was represented by the organic form (83 to 98%. The kidney and the liver of all fish species contained less than 50% OrgHg. We suggest that the low %OrgHg in the liver is related to different capacities or strategies of OrgHg detoxification by the fish.

  12. A pore-level scenario for the development of mixed-wettability in oil reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Kovscek, A.R.; Wong, H.; Radke, C.J.


    Understanding the role of thin films in porous media is vital if wettability is to be elucidated at the pore level. The type and thickness of films coating pore walls determines reservoir wettability and whether or not reservoir rock can be altered from its initial state of wettability. Pore shape, especially pore wall curvature, is an important factor in determining wetting-film thicknesses. Yet, pore shape and the physics of thin wetting films are generally neglected in models of flow in porous rocks. This paper incorporates thin-film forces into a collection of star-shaped capillary tubes model to describe the geological development of mixed-wettability in reservoir rock. Here, mixed-wettability refers to continuous and distinct oil and water-wetting surfaces coexisting in the porous medium. The proposed model emphasizes the remarkable role of thin films. New pore-level fluid configurations arise that are quite unexpected. For example, efficient water displacement of oil (i.e, low residual oil saturation) characteristic of mixed-wettability porous media is ascribed to interconnected oil lenses or rivulets which bridge the walls adjacent to a pore corner. Predicted residual oil saturations are approximately 35 % less in mixed-wet rock compared to completely water-wet rock. Calculated capillary pressure curves mimic those of mixed-wet porous media in the primary drainage of water, imbibition of water, and secondary drainage modes. Amott-Harvey indices range from {minus}0.18 to 0.36 also in good agreement with experimental values. (Morrow et al, 1986; Judhunandan and Morrow, 1991).

  13. An Assessment of Some Design Constraints on Heat Production of a 3D Conceptual EGS Model Using an Open-Source Geothermal Reservoir Simulation Code

    Energy Technology Data Exchange (ETDEWEB)

    Yidong Xia; Mitch Plummer; Robert Podgorney; Ahmad Ghassemi


    Performance of heat production process over a 30-year period is assessed in a conceptual EGS model with a geothermal gradient of 65K per km depth in the reservoir. Water is circulated through a pair of parallel wells connected by a set of single large wing fractures. The results indicate that the desirable output electric power rate and lifespan could be obtained under suitable material properties and system parameters. A sensitivity analysis on some design constraints and operation parameters indicates that 1) the fracture horizontal spacing has profound effect on the long-term performance of heat production, 2) the downward deviation angle for the parallel doublet wells may help overcome the difficulty of vertical drilling to reach a favorable production temperature, and 3) the thermal energy production rate and lifespan has close dependence on water mass flow rate. The results also indicate that the heat production can be improved when the horizontal fracture spacing, well deviation angle, and production flow rate are under reasonable conditions. To conduct the reservoir modeling and simulations, an open-source, finite element based, fully implicit, fully coupled hydrothermal code, namely FALCON, has been developed and used in this work. Compared with most other existing codes that are either closed-source or commercially available in this area, this new open-source code has demonstrated a code development strategy that aims to provide an unparalleled easiness for user-customization and multi-physics coupling. Test results have shown that the FALCON code is able to complete the long-term tests efficiently and accurately, thanks to the state-of-the-art nonlinear and linear solver algorithms implemented in the code.


    Directory of Open Access Journals (Sweden)

    H. Sudardja


    Full Text Available The modeling of earth dam was carried out in a drainage and seepage tank to analyze the seepage resulting from water level fluctuation in the upstream of the dam. The dam models were made of the mixture of Mt. Merapi sand deposit with the soil of sandy-silt from Wonosari area. The variations of sand content in the mixture were 100%; 90% and 80% and the upstream slope inclinations were 1:1; 1:1.5 and 1:2. The result showed that the dams with more sandy-silt in the mixture have smaller seepage and the dams with steeper upstream slope have greater seepage. During rapid rising of water level, the dams with steeper upstream slope have a high rising rate of upstream water level and higher height of downstream slope failure. Moreover, during rapid drawdown, the dams with gentler upstream slope have a smaller rate of upstream drawdown and lower height of upstream slope failure. The dams with more sandy-silt in the mixture have a higher value of rising rate and drawdown of upstream water level but lower height of downstream and upstream slope failure. In the dam management, continuous monitoring of the seepage resulting from reservoir water level fluctuation is required to avoid dam failure. Keywords: Earth dam, rapid rising, rapid drawdown, seepage, slope failure.

  15. Movement of Sediment Associated With Lowered Reservoir Levels in the Rio La Venta Arm of the Presa Netzahualcoyotl, Chiapas, Mexico (United States)

    Hilton, S.; de La Fuente, J.; Lisle, T. E.; Velasquez, J.; Allison, B.; Olson, B.; Quinones, R.


    A joint sedimentation study is currently underway at the Netzahualcoyotl reservoir in Chiapas, Mexico, involving the Comision Nacional de Areas Naturales Protegidas (CONANP) of the Secretaria de Medio Ambiente y Recursos Naturales and the USDA Forest Service. The reservoir is adjacent to the Reserva de la Biosfera, Selva El Ocote, administered by CONANP. Ongoing research is intended to provide watershed and reservoir managers with strategies to protect the resources of Rio La Venta canyon. The Rio La Venta arm of the reservoir is incised into karst terrain, with near-vertical limestone walls up to 300 meters high. The canyon is fed by two rivers, Rio La Selva and Rio Negro, and is surrounded by pristine tropical forest. The majority of the clastic sediment (predominantly sand and fine gravel) entering the reservoir originates in the headwaters of the two rivers which are underlain by weathered and dissected granitic terrain. Rapid sedimentation of the partially inundated canyon poses a threat to the aquatic ecosystem, as well as to recreational resources. Longitudinal and transverse profiles were surveyed in the inundated canyon in March of 2002 and repeated in April of 2003 when the reservoir level was 15 meters lower. The 2002 longitudinal profile shows an inflection from a slope of 0.0017 to one of 0.0075 at 7.2 km downstream of the mouth of Rio Negro. In 2003, the two slopes remained the same, but the bed lowered about 5 meters and the inflection point moved downstream about 2.3 km. We calculated that reservoir lowering in 2003 allowed the transport of 2.5 million cubic meters of sand further out into the reservoir. This volume is more than the average annual rate of filling up to the 2002 level since 1984 when sedimentation was not as advanced (De la Fuente et al., 2002), which was calculated disregarding loss of sediment to the main reservoir. Field observations at late dry season low flows in 2003 revealed active transport of sand and pebbles and formation

  16. Tabu search approaches for the multi-level warehouse layout problem with adjacency constraints (United States)

    Zhang, G. Q.; Lai, K. K.


    A new multi-level warehouse layout problem, the multi-level warehouse layout problem with adjacency constraints (MLWLPAC), is investigated. The same item type is required to be located in adjacent cells, and horizontal and vertical unit travel costs are product dependent. An integer programming model is proposed to formulate the problem, which is NP hard. Along with a cube-per-order index policy based heuristic, the standard tabu search (TS), greedy TS, and dynamic neighbourhood based TS are presented to solve the problem. The computational results show that the proposed approaches can reduce the transportation cost significantly.

  17. An integrated multi-level watershed-reservoir modeling system for examining hydrological and biogeochemical processes in small prairie watersheds. (United States)

    Zhang, Hua; Huang, Guo H; Wang, Dunling; Zhang, Xiaodong; Li, Gongchen; An, Chunjiang; Cui, Zheng; Liao, Renfei; Nie, Xianghui


    Eutrophication of small prairie reservoirs presents a major challenge in water quality management and has led to a need for predictive water quality modeling. Studies are lacking in effectively integrating watershed models and reservoir models to explore nutrient dynamics and eutrophication pattern. A water quality model specific to small prairie water bodies is also desired in order to highlight key biogeochemical processes with an acceptable degree of parameterization. This study presents a Multi-level Watershed-Reservoir Modeling System (MWRMS) to simulate hydrological and biogeochemical processes in small prairie watersheds. It integrated a watershed model, a hydrodynamic model and an eutrophication model into a flexible modeling framework. It can comprehensively describe hydrological and biogeochemical processes across different spatial scales and effectively deal with the special drainage structure of small prairie watersheds. As a key component of MWRMS, a three-dimensional Willows Reservoir Eutrophication Model (WREM) is developed to addresses essential biogeochemical processes in prairie reservoirs and to generate 3D distributions of various water quality constituents; with a modest degree of parameterization, WREM is able to meet the limit of data availability that often confronts the modeling practices in small watersheds. MWRMS was applied to the Assiniboia Watershed in southern Saskatchewan, Canada. Extensive efforts of field work and lab analysis were undertaken to support model calibration and validation. MWRMS demonstrated its ability to reproduce the observed watershed water yield, reservoir water levels and temperatures, and concentrations of several water constituents. Results showed that the aquatic systems in the Assiniboia Watershed were nitrogen-limited and sediment flux played a crucial role in reservoir nutrient budget and dynamics. MWRMS can provide a broad context of decision support for water resources management and water quality

  18. Levels and distribution of polybrominated diphenyl ethers in Three Gorges Reservoir, China

    Directory of Open Access Journals (Sweden)

    Jingxian Wang


    Full Text Available Polybrominated diphenyl ethers (PBDEs were investigated in water, sediments, suspended sediments and biofilms in Three Gorges Reservoir (TGR, China. Results showed that dissolved bioavailable PBDEs in water of TGR collected with semipermeable membrane device (SPMD-based virtual organisms (VOs were very low in the range of n.d. to 811 pg/g lipid and the detected compounds were mainly low molecular BDEs such as BDE-15, 17, 28, 47, 49, 66, 99 and 100. The PBDE levels in the sediment core collected near the dam were also very low in the range of 84–300 pg/g dw and the detected compounds were mainly large molecular BDEs such as BDE-196, 197, 206, 207 and 208. In suspended sediments and biofilms, the levels of PBDEs ranged from 298 to 52,843 pg/g dw and the detected compounds were also mainly large molecular BDEs such as BDE- 196, 197, 201, 203, 206, 207, 208 and 209. The dominant compound was BDE-209 which accounted for more than 90% of the total BDEs. Therefore, large molecular BDEs tended to be attached on fine particles. The vertical profile of BDEs on suspended sediments (SS showed that SSs in the middle depth of water contained high level of BDE-209. The phenomenon indicated that most of BDE-209 did not settle into the sediment in front of the dam, instead transported further to downstream.

  19. [Distribution of Mercury in Plants at Water-Level-Fluctuating Zone in the Three Gorges Reservoir]. (United States)

    Liang, Li; Wang, Yong-min; Li, Xian-yuan; Tang, Zhen-ya; Zhang, Xiang; Zhang, Cheng; WANG, Ding-yong


    The mercury (Hg) distribution and storage in plants at water-level-fluctuating zone (WLFZ) in the Three Gorges Reservoir were investigated by analyzing the total mercury(THg) and methylmercury ( MeHg) levels in different parts of plants collected from three typical sites including Shibaozhai, Zhenxi and Hanfeng Lake in WLFZ. The results indicated that THg and MeHg concentrations in plants ranged from (1.62 ± 0.57) to (49.42 ± 3.93) μg x kg(-1) and from (15.27 ± 7.09) to (1 974.67 ± 946.10) ng x kg(-1), respectively. In addition, THg levels in different plant parts followed the trend: root > leaf > stem, and similar trend for MeHg was observed with the highest level in root. An obvious spatial distribution was also found with the THg and MeHg levels in plants in Hanfeng higher than those in the same plants in the other two sampling sites (Shibaozhai and Zhenxi), and there was a difference of THg and MeHg storage in plants in various attitudes. The corresponding THg and MeHg storages were 145.3, 166.4, 124.3 and 88.2 mg x hm(-2), and 1.9, 2.7, 3.6 and 3.2 mg x hm(-2) in 145-150, 150-160, 160-170 and 170-175 m attitudes. The accumulation ability of dominant plants in WLFZ for THg (bioaccumulation factor, BAF 1).

  20. Response of aquatic macrophyte biomass to limnological changes under water level fluctuation in tropical reservoirs

    Directory of Open Access Journals (Sweden)

    E. G. Moura Júnior


    Full Text Available Abstract We evaluated the response of the biomass of aquatic macrophytes under limnological changes after water level fluctuation (WLF of two tropical reservoirs (R1 and R2, located in northeastern Brazil. Initially we tested the hypothesis that post-WLF limnological conditions and biomass of macrophytes increase or decrease, depending on the variable or species. We monitored a 4 × 50 m permanent plot, in four expeditions per period (pre- or post-WLF, assessing species biomass and 10 limnological variables. We utilized 0.25 × 0.25 m quadrats for biomass. Once the effect of WLF in limnological variables and species biomass was confirmed, we utilized Canonical Correspondence Analysis to understand the relationship between limnological variables and species biomass. The abundant and/or dominant species in pre-WLF of R1 ( Pistia stratiotes, Eichhornia crassipes and Salvinia auriculata and R2 (Paspalidium geminatum and S. auriculata reduced their biomass post-WLF and were correlated with temperature, total phosphorous and nitrate. The reduced biomass of P. stratiotes, E. crassipes and S. auriculata in post-WLF widened resource availability, allowing coexistence of species. Therefore, we suggest that the change of limnological conditions in post-WLF in artificial lakes acts only as a moderator factor of the interspecific interaction (especially coexistence, without direct relation between these conditions and species biomass.

  1. Top-Down CO Emissions Based On IASI Observations and Hemispheric Constraints on OH Levels (United States)

    Müller, J.-F.; Stavrakou, T.; Bauwens, M.; George, M.; Hurtmans, D.; Coheur, P.-F.; Clerbaux, C.; Sweeney, C.


    Assessments of carbon monoxide emissions through inverse modeling are dependent on the modeled abundance of the hydroxyl radical (OH) which controls both the primary sink of CO and its photochemical source through hydrocarbon oxidation. However, most chemistry transport models (CTMs) fall short of reproducing constraints on hemispherically averaged OH levels derived from methylchloroform (MCF) observations. Here we construct five different OH fields compatible with MCF-based analyses, and we prescribe those fields in a global CTM to infer CO fluxes based on Infrared Atmospheric Sounding Interferometer (IASI) CO columns. Each OH field leads to a different set of optimized emissions. Comparisons with independent data (surface, ground-based remotely sensed, aircraft) indicate that the inversion adopting the lowest average OH level in the Northern Hemisphere (7.8 × 105 molec cm-3, ˜18% lower than the best estimate based on MCF measurements) provides the best overall agreement with all tested observation data sets.

  2. A Market Framework for Enabling Electric Vehicles Flexibility Procurement at the Distribution Level Considering Grid Constraints

    DEFF Research Database (Denmark)

    Gadea, Ana; Marinelli, Mattia; Zecchino, Antonio


    In a context of extensive electrification of the transport sector, the use of flexibility services from electric vehicles (EVs) is becoming of paramount importance. This paper defines a market framework for enabling EVs flexibility at the distribution level, considering grid constraints. The main...... objective is to establish an adequate incentive system and proceed with an evaluation of EVs grid support for both users and DSOs, benchmarking it against the typical reinforcement solution. To exploit this framework, a billing process based on a two-price system is proposed for the controlled EV charging....... The derived methodology is applied to a piece of semi-urban Danish distribution grid consisting of 42 customers. The service remuneration spans from 16 €/year to 51 €/year per customer, depending on the incentive scheme, and avoids a standard reinforcement of approximately 6200 €/year. It is demonstrated...

  3. Relative lake level fluctuations and their influence on productivity and resilience in tropical lakes and reservoirs

    NARCIS (Netherlands)

    Kolding, J.; Zwieten, van P.A.M.


    Lakes and reservoirs are traditionally characterised from static morphological or chemical parameters such as depth and dissolved solids, while the dynamic impact of shifting water supplies has received little attention. There is increasing evidence, however, that the hydrodynamic regime in tropical

  4. A numerical index for evaluating phytoplankton response to changes in nutrient levels in deep mediterranean reservoirs

    Directory of Open Access Journals (Sweden)

    Nicola SECHI


    Full Text Available This paper proposes a new ecological index based on phytoplankton (MedPTI as suggested by the European Directive 2000/60/CE, Water Framework Directive (WFD. The index is a useful tool to verify the impacts of eutrophication in Mediterranean reservoirs belonging to different categories of the WFD. Multiple data sets were employed to develop the MedPTI index. The calibration data set included data collected from 30 Sardinian reservoirs in 1994. A list of 44 selected taxa was obtained and used for index calculation. A second dataset including 48 averaged annual values from 10 reservoirs was used. Results showed good correlation between MedPTI and concentration of total phosphorus, which was the limiting nutrient in these reservoirs. The trophic classifications determined using the index agreed with the results from the OECD probabilistic model on the same series of data. Finally, the index was included in an international exercise to compare the definition of reference conditions and quality class boundaries against indices used in other Mediterranean countries.

  5. Sensitivity Analysis of features in tolerancing based on constraint function level sets

    International Nuclear Information System (INIS)

    Ziegler, Philipp; Wartzack, Sandro


    Usually, the geometry of the manufactured product inherently varies from the nominal geometry. This may negatively affect the product functions and properties (such as quality and reliability), as well as the assemblability of the single components. In order to avoid this, the geometric variation of these component surfaces and associated geometry elements (like hole axes) are restricted by tolerances. Since tighter tolerances lead to significant higher manufacturing costs, tolerances should be specified carefully. Therefore, the impact of deviating component surfaces on functions, properties and assemblability of the product has to be analyzed. As physical experiments are expensive, methods of statistical tolerance analysis tools are widely used in engineering design. Current tolerance simulation tools lack of an appropriate indicator for the impact of deviating component surfaces. In the adoption of Sensitivity Analysis methods, there are several challenges, which arise from the specific framework in tolerancing. This paper presents an approach to adopt Sensitivity Analysis methods on current tolerance simulations with an interface module, which bases on level sets of constraint functions for parameters of the simulation model. The paper is an extension and generalization of Ziegler and Wartzack [1]. Mathematical properties of the constraint functions (convexity, homogeneity), which are important for the computational costs of the Sensitivity Analysis, are shown. The practical use of the method is illustrated in a case study of a plain bearing. - Highlights: • Alternative definition of Deviation Domains. • Proof of mathematical properties of the Deviation Domains. • Definition of the interface between Deviation Domains and Sensitivity Analysis. • Sensitivity analysis of a gearbox to show the methods practical use

  6. Availability, Level of Use and Constraints to Use of Electronic Resources by Law Lecturers in Public Universities in Nigeria (United States)

    Amusa, Oyintola Isiaka; Atinmo, Morayo


    (Purpose) This study surveyed the level of availability, use and constraints to use of electronic resources among law lecturers in Nigeria. (Methodology) Five hundred and fifty-two law lecturers were surveyed and four hundred and forty-two responded. (Results) Data analysis revealed that the level of availability of electronic resources for the…

  7. Multi variate regression model of the water level and production rate time series of the geothermal reservoir Waiwera (New Zealand) (United States)

    Kühn, Michael; Schöne, Tim


    Water management tools are essential to ensure the conservation of natural resources. The geothermal hot water reservoir below the village of Waiwera, on the Northern Island of New Zealand is used commercially since 1863. The continuous production of 50 °C hot geothermal water, to supply hotels and spas, has a negative impact on the reservoir. Until the year 1969 from all wells drilled the warm water flow was artesian. Due to overproduction the water needs to be pumped up nowadays. Further, within the years 1975 to 1976 the warm water seeps on the beach of Waiwera ran dry. In order to protect the reservoir and the historical and tourist site in the early 1980s a water management plan was deployed. The "Auckland Council" established guidelines to enable a sustainable management of the resource [1]. The management plan demands that the water level in the official and appropriate observation well of the council is 0.5 m above sea level throughout the year in average. Almost four decades of data (since 1978 until today) are now available [2]. For a sustainable water management, it is necessary to be able to forecast the water level as a function of the production rates in the production wells. The best predictions are provided by a multivariate regression model of the water level and production rate time series, which takes into account the production rates of individual wells. It is based on the inversely proportional relationship between the independent variable (production rate) and the dependent variable (measured water level). In production scenarios, a maximum total production rate of approx. 1,100 m3 / day is determined in order to comply with the guidelines of the "Auckland Council". [1] Kühn M., Stöfen H. (2005) A reactive flow model of the geothermal reservoir Waiwera, New Zealand. Hydrogeology Journal 13, 606-626, doi: 10.1007/s10040-004-0377-6 [2] Kühn M., Altmannsberger C. (2016) Assessment of data driven and process based water management tools for

  8. Amphibians biochemical indices from reservoirs of different levels of waste discharge

    Directory of Open Access Journals (Sweden)

    I. N. Zalipuha


    Full Text Available Influence of uranium mining and processing wastes on the metabolism of common amphibian species of the Dnieper region – the marsh frog (Pelophylax ridibundus – from differently contaminated reservoirs. The change of protein, lipids and carbohydrates in organs and tissues of frogs with ageing and under influence of the pollution. Considerable increase of energy consumption at the expense of lipids and carbohydrates is one of biochemical adaptations. It promotes partial resistance of amphibians to the influence of uranium mining wastes.

  9. Information retrieval system: impacts of water-level changes on uses of federal storage reservoirs of the Columbia River.

    Energy Technology Data Exchange (ETDEWEB)

    Fickeisen, D.H.; Cowley, P.J.; Neitzel, D.A.; Simmons, M.A.


    A project undertaken to provide the Bonneville Power Administration (BPA) with information needed to conduct environmental assessments and meet requirements of the National Environmental Policy Act (NEPA) and the Pacific Northwest Electric Power Planning and Conservation Act (Regional Act) is described. Access to information on environmental effects would help BPA fulfill its responsibilities to coordinate power generation on the Columbia River system, protect uses of the river system (e.g., irrigation, recreation, navigation), and enhance fish and wildlife production. Staff members at BPA identified the need to compile and index information resources that would help answer environmental impact questions. A computer retrieval system that would provide ready access to the information was envisioned. This project was supported by BPA to provide an initial step toward a compilation of environmental impact information. Scientists at Pacific Northwest Laboratory (PNL) identified, gathered, and evaluated information related to environmental effects of water level on uses of five study reservoirs and developed and implemented and environmental data retrieval system, which provides for automated storage and retrieval of annotated citations to published and unpublished information. The data retrieval system is operating on BPA's computer facility and includes the reservoir water-level environmental data. This project was divided into several tasks, some of which were conducted simultaneously to meet project deadlines. The tasks were to identify uses of the five study reservoirs, compile and evaluate reservoir information, develop a data entry and retrieval system, identify and analyze research needs, and document the data retrieval system and train users. Additional details of the project are described in several appendixes.

  10. Edge effects and geometric constraints: a landscape-level empirical test. (United States)

    Ribeiro, Suzy E; Prevedello, Jayme A; Delciellos, Ana Cláudia; Vieira, Marcus Vinícius


    Edge effects are pervasive in landscapes yet their causal mechanisms are still poorly understood. Traditionally, edge effects have been attributed to differences in habitat quality along the edge-interior gradient of habitat patches, under the assumption that no edge effects would occur if habitat quality was uniform. This assumption was questioned recently after the recognition that geometric constraints tend to reduce population abundances near the edges of habitat patches, the so-called geometric edge effect (GEE). Here, we present the first empirical, landscape-level evaluation of the importance of the GEE in shaping abundance patterns in fragmented landscapes. Using a data set on the distribution of small mammals across 18 forest fragments, we assessed whether the incorporation of the GEE into the analysis changes the interpretation of edge effects and the degree to which predictions based on the GEE match observed responses. Quantitative predictions were generated for each fragment using simulations that took into account home range, density and matrix use for each species. The incorporation of the GEE into the analysis changed substantially the interpretation of overall observed edge responses at the landscape scale. Observed abundances alone would lead to the conclusion that the small mammals as a group have no consistent preference for forest edges or interiors and that the black-eared opossum Didelphis aurita (a numerically dominant species in the community) has on average a preference for forest interiors. In contrast, incorporation of the GEE suggested that the small mammal community as a whole has a preference for forest edges, whereas D. aurita has no preference for forest edges or interiors. Unexplained variance in edge responses was reduced by the incorporation of GEE, but remained large, varying greatly on a fragment-by-fragment basis. This study demonstrates how to model and incorporate the GEE in analyses of edge effects and that this

  11. The effect of water level fluctuation on tributary spawning migration of reservoir fish

    Czech Academy of Sciences Publication Activity Database

    Hladík, Milan; Kubečka, Jan


    Roč. 4, č. 4 (2004), s. 449-457 ISSN 1642-3593. [Ecohydrology and physical habitat modifications in lakes. Mondsee, 26.11.2003-28.11.2003] R&D Projects: GA ČR(CZ) GA206/02/0520; GA AV ČR(CZ) IBS6017004; GA AV ČR(CZ) IAA6017201; GA AV ČR(CZ) KSK6005114 Institutional research plan: CEZ:AV0Z6017912 Keywords : freshwater fish spawning migration * tributary * reservoir Subject RIV: GL - Fishing

  12. New constraints on late Holocene eustatic sea-level changes from Mahé, Seychelles (United States)

    Woodroffe, Sarah A.; Long, Antony J.; Milne, Glenn A.; Bryant, Charlotte L.; Thomas, Alexander L.


    This study provides new estimates of globally integrated ice sheet melt during the late Holocene (since 4 ka BP) from Seychelles in the western Indian Ocean, a tectonically stable, far field location where the necessary Glacial-Isostatic Adjustment (GIA) correction is small and is relatively insensitive to predictions using different Earth viscosity profiles. We compare sea level data from Seychelles to estimates of eustasy from two GIA models, ICE-5G and EUST3, which represent end-members in the quantity of global melt during the late Holocene. We use data from a range of coastal environments including fringing reef, present day beaches, fossil plateau and mangrove deposits on the largest island of the Seychelles archipelago, Mahé to reconstruct relative sea-level changes. Our data suggest that extensive coastal deposits of carbonate-rich sands that fringe the west coast formed in the last 2 ka and the horizontal nature of their surface topography suggests RSL stability during this period. Mangrove sediments preserved behind these deposits and in river mouths date to c. 2 ka and indicate that RSL was between -2 m and present during this interval. Correcting the reconstructed sea level data using a suite of optimal GIA models based on the two ice models mentioned above and a large number (c. 350) of Earth viscosity models gives a result that is consistent with the sedimentological constraints. When uncertainties in both model results and data are considered, it is possible to rule out eustatic sea levels below c. 2 m and more than a few decimetres above present during the past two millennia. This uncertainty is dominated by error in the reconstructions rather than the model predictions. We note, however, that our estimates of eustasy are more compatible with the EUST3 model compared to the ICE-5G model during the late Holocene (2-1 ka BP). Our evidence from Seychelles shows that the timing of when eustatic sea level first rose close to present is between the

  13. Renewable Energy Prices in State-Level Feed-in Tariffs: Federal Law Constraints and Possible Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Hempling, S.; Elefant, C.; Cory, K.; Porter, K.


    State legislatures and state utility commissions trying to attract renewable energy projects are considering feed-in tariffs, which obligate retail utilities to purchase electricity from renewable producers under standard arrangements specifying prices, terms, and conditions. The use of feed-in tariffs simplifies the purchase process, provides revenue certainty to generators, and reduces the cost of financing generating projects. However, some argue that federal law--including the Public Utility Regulatory Policies Act of 1978 (PURPA) and the Federal Power Act of 1935 (FPA)--constrain state-level feed-in tariffs. This report seeks to reduce the legal uncertainties for states contemplating feed-in tariffs by explaining the constraints imposed by federal statutes. It describes the federal constraints, identifies transaction categories that are free of those constraints, and offers ways for state and federal policymakers to interpret or modify existing law to remove or reduce these constraints. This report proposes ways to revise these federal statutes. It creates a broad working definition of a state-level feed-in tariff. Given this definition, this report concludes there are paths to non-preempted, state-level feed-in tariffs under current federal law.

  14. The 3.6 ka Aniakchak tephra in the Arctic Ocean: a constraint on the Holocene radiocarbon reservoir age in the Chukchi Sea

    DEFF Research Database (Denmark)

    Pearce, C.; Varhelyi, A.; Wastegård, S.


    to ice rafting as an important secondary transport mechanism of volcanic ash. Combined with radiocarbon dates on mollusks in the same sediment core, the volcanic marker is used to calculate a marine radiocarbon reservoir age offset ΔR = 477 ± 60 years. This relatively high value may be explained...... reservoir age offset, is the first of its kind in the Arctic Ocean and provides an important framework for improving chronologies and correlating marine sediment archives in this region. Core 2PC has a high sediment accumulation rate averaging 200 cm/kyr throughout the last 4000 years, and the chronology......The caldera-forming eruption of the Aniakchak volcano in the Aleutian Range on the Alaskan Peninsula at 3.6 cal ka BP, was one of the largest Holocene eruptions worldwide. The resulting ash is found as a visible sediment layer in several Alaskan sites and as a cryptotephra on Newfoundland...

  15. Quantification of Libby Reservoir Levels Needed to Maintain or Enhance Reservoir Fisheries, 1990-1994 Investigations of Fish Entrainment Through Libby Dam.

    Energy Technology Data Exchange (ETDEWEB)

    Skaar, Don


    We investigated fish entrainment through Libby Dam from December 1990 to June 1994. This study was one portion of the effort by the Montana Department of Fish, Wildlife and Parks to quantify Libby Dam operations necessary to maintain or enhance Libby Reservoir fisheries.

  16. Accuracy enhancement for forecasting water levels of reservoirs and river streams using a multiple-input-pattern fuzzification approach. (United States)

    Valizadeh, Nariman; El-Shafie, Ahmed; Mirzaei, Majid; Galavi, Hadi; Mukhlisin, Muhammad; Jaafar, Othman


    Water level forecasting is an essential topic in water management affecting reservoir operations and decision making. Recently, modern methods utilizing artificial intelligence, fuzzy logic, and combinations of these techniques have been used in hydrological applications because of their considerable ability to map an input-output pattern without requiring prior knowledge of the criteria influencing the forecasting procedure. The artificial neurofuzzy interface system (ANFIS) is one of the most accurate models used in water resource management. Because the membership functions (MFs) possess the characteristics of smoothness and mathematical components, each set of input data is able to yield the best result using a certain type of MF in the ANFIS models. The objective of this study is to define the different ANFIS model by applying different types of MFs for each type of input to forecast the water level in two case studies, the Klang Gates Dam and Rantau Panjang station on the Johor river in Malaysia, to compare the traditional ANFIS model with the new introduced one in two different situations, reservoir and stream, showing the new approach outweigh rather than the traditional one in both case studies. This objective is accomplished by evaluating the model fitness and performance in daily forecasting.

  17. Symbol recognition via statistical integration of pixel-level constraint histograms: a new descriptor. (United States)

    Yang, Su


    A new descriptor for symbol recognition is proposed. 1) A histogram is constructed for every pixel to figure out the distribution of the constraints among the other pixels. 2) All the histograms are statistically integrated to form a feature vector with fixed dimension. The robustness and invariance were experimentally confirmed.

  18. Displacement response of a concrete arch dam to seasonal temperature fluctuations and reservoir level rise during the first filling period: evidence from geodetic data


    Cemal Ozer Yigit; Salih Alcay; Ayhan Ceylan


    The present study evaluates the dynamic behaviour of the Ermenek Dam, the second highest dam in Turkey, based on conventional geodetic measurements and Finite Element Model (FEM) analyses during its first filling period. In total, eight periods of measured deformation are considered from the end of construction until the reservoir reached its full capacity. The displacement response of the dam to the reservoir level and to seasonal temperature variations is examined in detail. Time series of ...

  19. Integrating Compact Constraint and Distance Regularization with Level Set for Hepatocellular Carcinoma (HCC) Segmentation on Computed Tomography (CT) Images (United States)

    Gui, Luying; He, Jian; Qiu, Yudong; Yang, Xiaoping


    This paper presents a variational level set approach to segment lesions with compact shapes on medical images. In this study, we investigate to address the problem of segmentation for hepatocellular carcinoma which are usually of various shapes, variable intensities, and weak boundaries. An efficient constraint which is called the isoperimetric constraint to describe the compactness of shapes is applied in this method. In addition, in order to ensure the precise segmentation and stable movement of the level set, a distance regularization is also implemented in the proposed variational framework. Our method is applied to segment various hepatocellular carcinoma regions on Computed Tomography images with promising results. Comparison results also prove that the proposed method is more accurate than other two approaches.

  20. The disposal of high level radioactive waste in argillaceous host rocks identification of parameters, constraints and geological assessment priorities

    International Nuclear Information System (INIS)

    Horseman, S.T.


    The purpose of this report, commissioned by ENRESA, is to examine the characteristics, properties and responses of argillaceous media (clays and more indurated mudrocks) in some detail in order to identify the main parameters that will influence the radiological safety of a deep underground facility for the disposal of high-level radioactive wastes (HLW) and to highlight possible constraints and other important issues relating to the construction, operation and performance of such a facility

  1. Using a Bayesian Probabilistic Forecasting Model to Analyze the Uncertainty in Real-Time Dynamic Control of the Flood Limiting Water Level for Reservoir Operation

    DEFF Research Database (Denmark)

    Liu, Dedi; Li, Xiang; Guo, Shenglian


    Dynamic control of the flood limiting water level (FLWL) is a valuable and effective way to maximize the benefits from reservoir operation without exceeding the design risk. In order to analyze the impacts of input uncertainty, a Bayesian forecasting system (BFS) is adopted. Applying quantile water...... inflow values and their uncertainties obtained from the BFS, the reservoir operation results from different schemes can be analyzed in terms of benefits, dam safety, and downstream impacts during the flood season. When the reservoir FLWL dynamic control operation is implemented, there are two fundamental......, also deterministic water inflow was tested. The proposed model in the paper emphasizes the importance of analyzing the uncertainties of the water inflow forecasting system for real-time dynamic control of the FLWL for reservoir operation. For the case study, the selected quantile inflow from...

  2. Low-level HIV-1 replication and the dynamics of the resting CD4+ T cell reservoir for HIV-1 in the setting of HAART

    Directory of Open Access Journals (Sweden)

    Wilke Claus O


    Full Text Available Abstract Background In the setting of highly active antiretroviral therapy (HAART, plasma levels of human immunodeficiency type-1 (HIV-1 rapidly decay to below the limit of detection of standard clinical assays. However, reactivation of remaining latently infected memory CD4+ T cells is a source of continued virus production, forcing patients to remain on HAART despite clinically undetectable viral loads. Unfortunately, the latent reservoir decays slowly, with a half-life of up to 44 months, making it the major known obstacle to the eradication of HIV-1 infection. However, the mechanism underlying the long half-life of the latent reservoir is unknown. The most likely potential mechanisms are low-level viral replication and the intrinsic stability of latently infected cells. Methods Here we use a mathematical model of T cell dynamics in the setting of HIV-1 infection to probe the decay characteristics of the latent reservoir upon initiation of HAART. We compare the behavior of this model to patient derived data in order to gain insight into the role of low-level viral replication in the setting of HAART. Results By comparing the behavior of our model to patient derived data, we find that the viral dynamics observed in patients on HAART could be consistent with low-level viral replication but that this replication would not significantly affect the decay rate of the latent reservoir. Rather than low-level replication, the intrinsic stability of latently infected cells and the rate at which they are reactivated primarily determine the observed reservoir decay rate according to the predictions of our model. Conclusion The intrinsic stability of the latent reservoir has important implications for efforts to eradicate HIV-1 infection and suggests that intensified HAART would not accelerate the decay of the latent reservoir.

  3. Low-level HIV-1 replication and the dynamics of the resting CD4+ T cell reservoir for HIV-1 in the setting of HAART (United States)

    Sedaghat, Ahmad R; Siliciano, Robert F; Wilke, Claus O


    Background In the setting of highly active antiretroviral therapy (HAART), plasma levels of human immunodeficiency type-1 (HIV-1) rapidly decay to below the limit of detection of standard clinical assays. However, reactivation of remaining latently infected memory CD4+ T cells is a source of continued virus production, forcing patients to remain on HAART despite clinically undetectable viral loads. Unfortunately, the latent reservoir decays slowly, with a half-life of up to 44 months, making it the major known obstacle to the eradication of HIV-1 infection. However, the mechanism underlying the long half-life of the latent reservoir is unknown. The most likely potential mechanisms are low-level viral replication and the intrinsic stability of latently infected cells. Methods Here we use a mathematical model of T cell dynamics in the setting of HIV-1 infection to probe the decay characteristics of the latent reservoir upon initiation of HAART. We compare the behavior of this model to patient derived data in order to gain insight into the role of low-level viral replication in the setting of HAART. Results By comparing the behavior of our model to patient derived data, we find that the viral dynamics observed in patients on HAART could be consistent with low-level viral replication but that this replication would not significantly affect the decay rate of the latent reservoir. Rather than low-level replication, the intrinsic stability of latently infected cells and the rate at which they are reactivated primarily determine the observed reservoir decay rate according to the predictions of our model. Conclusion The intrinsic stability of the latent reservoir has important implications for efforts to eradicate HIV-1 infection and suggests that intensified HAART would not accelerate the decay of the latent reservoir. PMID:18171475

  4. Quantum theory of phonon-mediated decoherence and relaxation of two-level systems in a structured electromagnetic reservoir (United States)

    Roy, Chiranjeeb

    In this thesis we study the role of nonradiative degrees of freedom on quantum optical properties of mesoscopic quantum dots placed in the structured electromagnetic reservoir of a photonic crystal. We derive a quantum theory of the role of acoustic and optical phonons in modifying the optical absorption lineshape, polarization dynamics, and population dynamics of a two-level atom (quantum dot) in the "colored" electromagnetic vacuum of a photonic band gap (PBG) material. This is based on a microscopic Hamiltonian describing both radiative and vibrational processes quantum mechanically. Phonon sidebands in an ordinary electromagnetic reservoir are recaptured in a simple model of optical phonons using a mean-field factorization of the atomic and lattice displacement operators. Our formalism is then used to treat the non-Markovian dynamics of the same system within the structured electromagnetic density of states of a photonic crystal. We elucidate the extent to which phonon-assisted decay limits the lifetime of a single photon-atom bound state and derive the modified spontaneous emission dynamics due to coupling to various phonon baths. We demonstrate that coherent interaction with undamped phonons can lead to enhanced lifetime of a photon-atom bound state in a PBG by (i) dephasing and reducing the transition electric dipole moment of the atom and (ii) reducing the quantum mechanical overlap of the state vectors of the excited and ground state (polaronic shift). This results in reduction of the steady-state atomic polarization but an increase in the fractionalized upper state population in the photon-atom bound state. We demonstrate, on the other hand, that the lifetime of the photon-atom bound state in a PBG is limited by the lifetime of phonons due to lattice anharmonicities (break-up of phonons into lower energy phonons) and purely nonradiative decay. We demonstrate how these additional damping effects limit the extent of the polaronic (Franck-Condon) shift of

  5. Displacement response of a concrete arch dam to seasonal temperature fluctuations and reservoir level rise during the first filling period: evidence from geodetic data

    Directory of Open Access Journals (Sweden)

    Cemal Ozer Yigit


    Full Text Available The present study evaluates the dynamic behaviour of the Ermenek Dam, the second highest dam in Turkey, based on conventional geodetic measurements and Finite Element Model (FEM analyses during its first filling period. In total, eight periods of measured deformation are considered from the end of construction until the reservoir reached its full capacity. The displacement response of the dam to the reservoir level and to seasonal temperature variations is examined in detail. Time series of apparent total displacements at the middle of the crest of the dam exhibits periodicity and linear trends. Correlation analysis revealed that periodic and linear displacement responses of the dam are related to variations of seasonal temperature and linearly increased reservoir level, respectively, indicating a relation between temperature, water load and dam deformation. It is also concluded that measured deformations based on geodetic data show good agreement with the predicted deformation obtained by the FEM analysis.

  6. Implementation of the - Constraint Method in Special Class of Multi-objective Fuzzy Bi-Level Nonlinear Problems

    Directory of Open Access Journals (Sweden)

    Azza Hassan Amer


    Full Text Available Geometric programming problem is a powerful tool for solving some special type nonlinear programming problems. In the last few years we have seen a very rapid development on solving multiobjective geometric programming problem. A few mathematical programming methods namely fuzzy programming, goal programming and weighting methods have been applied in the recent past to find the compromise solution. In this paper, -constraint method has been applied in bi-level multiobjective geometric programming problem to find the Pareto optimal solution at each level. The equivalent mathematical programming problems are formulated to find their corresponding value of the objective function based on the duality theorem at eash level. Here, we have developed a new algorithm for fuzzy programming technique to solve bi-level multiobjective geometric programming problems to find an optimal compromise solution. Finally the solution procedure of the fuzzy technique is illustrated by a numerical example

  7. Response of littoral macrophytes to water level fluctuations in a storage reservoir

    Czech Academy of Sciences Publication Activity Database

    Krolová, Monika; Čížková, Hana; Hejzlar, Josef; Poláková, S.


    Roč. 408, May (2013), 07p1-07p21 ISSN 1961-9502 R&D Projects: GA ČR(CZ) GA206/09/1764; GA MŠk(CZ) 7E11059 Grant - others:EC ENV(CZ) FP7 244121 Program:FP7 Institutional research plan: CEZ:AV0Z60170517 Institutional support: RVO:60077344 ; RVO:67179843 Keywords : littoral macrophytes * eulittoral * water level fluctuation * European Water Framework Directive * ecophases Subject RIV: DA - Hydrology ; Limnology Impact factor: 0.622, year: 2013

  8. Reservoir characterisation by a binary level set method and adaptive multiscale estimation

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Lars Kristian


    The main focus of this work is on estimation of the absolute permeability as a solution of an inverse problem. We have both considered a single-phase and a two-phase flow model. Two novel approaches have been introduced and tested numerical for solving the inverse problems. The first approach is a multi scale zonation technique which is treated in Paper A. The purpose of the work in this paper is to find a coarse scale solution based on production data from wells. In the suggested approach, the robustness of an already developed method, the adaptive multi scale estimation (AME), has been improved by utilising information from several candidate solutions generated by a stochastic optimizer. The new approach also suggests a way of combining a stochastic and a gradient search method, which in general is a problematic issue. The second approach is a piecewise constant level set approach and is applied in Paper B, C, D and E. Paper B considers the stationary single-phase problem, while Paper C, D and E use a two-phase flow model. In the two-phase flow problem we have utilised information from both production data in wells and spatially distributed data gathered from seismic surveys. Due to the higher content of information provided by the spatially distributed data, we search solutions on a slightly finer scale than one typically does with only production data included. The applied level set method is suitable for reconstruction of fields with a supposed known facies-type of solution. That is, the solution should be close to piecewise constant. This information is utilised through a strong restriction of the number of constant levels in the estimate. On the other hand, the flexibility in the geometries of the zones is much larger for this method than in a typical zonation approach, for example the multi scale approach applied in Paper A. In all these papers, the numerical studies are done on synthetic data sets. An advantage of synthetic data studies is that the true

  9. Farm-level constraints on the domestic supply of perennial energy crops in the UK

    International Nuclear Information System (INIS)

    Sherrington, Chris; Bartley, Justin; Moran, Dominic


    There are a number of estimates of the land area that could potentially be dedicated to perennial energy crops such as short rotation coppice (SRC) willow and miscanthus in the UK, but little is known about how farmers will respond to the opportunities presented by these relatively novel crops. Perennial energy crops face competition from other, arguably more flexible, uses of farmland, and if not seen as attractive propositions to individual farmers, they will not be grown. Farmers' decisions are therefore a key constraint on potential supply. This paper reviews the policy background and considers whether policy is based on any consideration of likely supply response, before presenting outcomes of focus groups composed of farmers who already grow or are considering growing perennial energy crops. There appear to be a number of barriers to adoption. In addition to concerns over the security of contracts, the current high wheat price increases the opportunity cost of committing land to perennial energy crops. There are also worries about the impact of willow roots on field drains and the cost of returning the land to other uses. This paper outlines a number of issues of importance to policy makers and suggests future research needs

  10. Pore level investigation of oil mobility enhancement in heavy oil reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz-Arango, J.D.; Kantzas, A. [Calgary Univ., AB (Canada)


    This study investigated the effect of water lubrication on oil mobility at the pore level. The aim of the study was to investigate the foamy oil phenomenon associated with the solution-gas drive mechanism that occurs during heavy oil production. The study considered the physical principles of momentum transfer and viscous coupling in multiphase flow through porous media. Capillary models were used to derive expressions for the shapes of fluid-fluid interfaces, relative permeabilities, and velocity distributions. The Galerkin method was used to solve 2-phase flow problems, and various cross-sectional geometries were analyzed. Results showed that the maximum stable wetting phase saturation, and the corresponding minimum stable non-wetting phase situation were functions of the viscosity ratio. The study demonstrated that viscous coupling is an important factor in porous media multiphase flow. Viscous coupling effects were non-existent in the wetting phase, but became very important during the non-wetting phase. It was concluded that viscosity ratios have a significant influence on the relative permeabilities of heavy oil systems. 25 refs., 14 figs.

  11. New Constraints from the Seychelles on the Timing and Magnitude of Peak Global Mean Sea Level during the Last Interglacial (United States)

    Vyverberg, K.; Dechnik, B.; Dutton, A.; Webster, J.; Zwartz, D.; Edwards, R. L.


    Projecting the rate of future sea-level rise remains a primary challenge associated with continued climate change. However, uncertainties remain in our understanding of the rate of polar ice sheet retreat in warmer-than-present climates. To address this issue, we present a new sea level reconstruction from the tectonically stable granitic Seychelles based on Last Interglacial coral ages and elevations within their sedimentary and stratigraphic context, including estimates of paleo-water depth based on newly defined coralgal assemblages. The reef facies analyzed here has a narrow and shallow paleowater depth range (dwelling barnacles. These disturbance layers may have been generated through internal reef processes and/or external agents, including coral disease, bleaching, predation, hurricanes, or sub-aerial exposure. In total, these new observations provide improved constraints on the timing, magnitude, and rates of sea-level rise during the Last Interglacial.

  12. Sedimentary constraints on late Quaternary lake-level fluctuations at Bear Lake, Utah and Idaho (United States)

    Smoot, J.P.; Rosenbaum, J.G.


    A variety of sedimentological evidence was used to construct the lake-level history for Bear Lake, Utah and Idaho, for the past ???25,000 years. Shorelines provide evidence of precise lake levels, but they are infrequently preserved and are poorly dated. For cored sediment similar to that in the modern lake, grain-size distributions provide estimates of past lake depths. Sedimentary textures provide a highly sensitive, continuous record of lake-level changes, but the modern distribution of fabrics is poorly constrained, and many ancient features have no modern analog. Combining the three types of data yields a more robust lake-level history than can be obtained from any one type alone. When smooth age-depth models are used, lake-level curves from multiple cores contain inconsistent intervals (i.e., one record indicates a rising lake level while another record indicates a falling lake level). These discrepancies were removed and the multiple records were combined into a single lake-level curve by developing age-depth relations that contain changes in deposition rate (i.e., gaps) where indicated by sedimentological evidence. The resultant curve shows that, prior to 18 ka, lake level was stable near the modern level, probably because the lake was overflowing. Between ca. 17.5 and 15.5 ka, lake level was ???40 m below the modern level, then fluctuated rapidly throughout the post-glacial interval. Following a brief rise centered ca. 15 ka ( = Raspberry Square phase), lake level lowered again to 15-20 m below modern from ca. 14.8-11.8 ka. This regression culminated in a lowstand to 40 m below modern ca. 12.5 ka, before a rapid rise to levels above modern ca. 11.5 ka. Lake level was typically lower than present throughout the Holocene, with pronounced lowstands 15-20 m below the modern level ca. 10-9, 7.0, 6.5-4.5, 3.5, 3.0-2.5, 2.0, and 1.5 ka. High lake levels near or above the modern lake occurred ca. 8.5-8.0, 7.0-6.5, 4.5-3.5, 2.5, and 0.7 ka. This lake-level history

  13. Evaluation of storm event inputs on levels of gross primary production and respiration in a drinking water reservoir

    DEFF Research Database (Denmark)

    Samal, Nihar; Stæhr, Peter A.; Pierson, Donald C.

    Weather related episodic events are typically unpredictable and the episodic inputs of dissolved and particulate material during storm events can have important effects on lake and reservoir ecosystem function and also impact reservoir drinking water quality.   We evaluate the impacts of storm...... events using vertical profiles of temperature, dissolved oxygen, turbidity and chlorophyll automatically collected at 6 hour intervals in West basin of Ashokan Reservoir, which is a part of the New York City drinking water supply. Using data from before, during and after storm events, we examine how...... the balance between GPP and R is influenced by storm related increases in turbidity and dissolved organic matter, which would in turn influence light attenuation and bacterial production. Storm driven inputs to the reservoir periodically resulted in large input of suspended sediments raising water turbidity...

  14. A sample-based method for perishable good inventory control with a service level constraint

    NARCIS (Netherlands)

    Hendrix, Eligius M.T.; Pauls-Worm, Karin G.J.; Rossi, Roberto; Alcoba, Alejandro G.; Haijema, Rene


    This paper studies the computation of so-called order-upto levels for a stochastic programming inventory problem of a perishable product. Finding a solution is a challenge as the problem enhances a perishable product, fixed ordering cost and non-stationary stochastic demand with a service level

  15. Study on a technology to afforest water level varying part of a reservoir; Chosuichi suii hendobu ryokuka gijutsu ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Onodera, O.; Matsubara, K.; Koyama, S. [Hokkaido Electric Power Co. Inc., Sapporo (Japan)


    Equisetum was noted as a plant adaptable to stringent environment referred to as the water level varying part of a reservoir, and was used for afforestation trials. The afforestation trials were performed at the reservoir of Uryuu Dam No. 1 and the regulating reservoir of Moiwa Dam of Hokkaido Electric Power Company. Although the rate of water level variation is small at Uryuu Dam No. 1, it is necessary for Equisetum to withstand submergence and drought for an extended period of time. Moiwa Dam has high water level variation rate, but its water depth is small, and the reservoir is free of long-term submergence and drought. As a result of long-term observation from 1993 through 1997, Equisetum was found having grown well at lower altitude part with higher submergence frequency. It has grown favorably even in parts where submergence rate reaches about 80%. However, at higher altitude with submergence rate of 10% or lower, decrement trend was seen. At Moiwa Dam, Equisetum was all buried in accumulated sand and earth, revealing that such an environment is unsuitable for Equisetum as the one subject to effect of sand and earth that flow in during freshet. (NEDO)

  16. New constraints on MIS 7 and 5 relative sea-level at Bermuda: a speleothem approach (United States)

    Wainer, Karine; Henderson, Gideon; Mason, Andrew; Thomas, Alexander; Williams, Bruce; Rowe, Mark; van Hengstum, Peter; Chandler, Robert


    It is now widely accepted that a sea-level rise is associated with global warming [1]. However, its rate, and the height it might reach by the end of the century remain poorly constrained. This study aims to provide better information and precision on the rates and magnitudes of past sea-level change, for periods when sea-level is close to its modern value, using speleothems from Bermudian caves. Speleothems interrupt their growth when they are submerged by sea-water, so U-Th dating periods of growth in coastal sites allows the reconstruction of past sea-level variation versus absolute time [e.g. 2,3,4]. We will present new MC-ICP-MS U-Th ages, trace elements and isotopic data from a set of speleothems (stalagmites, stalactites, flowstones) collected from -14 to +12 m versus modern sea level from several caves in this northern Atlantic archipelago. Relative sea-level (RSL) at Bermuda is of particular interest because it is at a distance from northern hemisphere ice sheets where the isostatic response to ice-unloading is uncertain. RSL reconstruction therefore provides both an indicates of possible rates of sea level change, and a test for glacial-isostatic-adjustment (GIA) models. We will present new relative sea level data for late MIS7, and the different highstands of MIS5. The RSL at Bermuda for these episodes appears to be higher than present. For MIS5a, this is significantly distinct from what is expected from the eustatic sea level. These results will be considered in the context of previous assessments of eustatic change, and of GIA models. [1] Intergovernmental Panel on Climate Change (2007) Contribution of Working Group I to the Fourth Assessment Report, Cambridge Univ. Press. [2] Harmon et al. (1981) Nature 289, 357-360. [3] Richards et al. (1994) Nature 367, 481-483. [4] Bard (2002) EPSL 196, 135-146.

  17. Development of a 400 Level 3C Clamped Downhole Seismic Receiver Array for 3D Borehole Seismic Imaging of Gas Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Bjorn N. P. Paulsson


    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to perform high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology has been hampered by the lack of acquisition technology necessary to record large volumes of high frequency, high signal-to-noise-ratio borehole seismic data. This project took aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array has removed the technical acquisition barrier for recording the data volumes necessary to do high resolution 3D VSP and 3D cross-well seismic imaging. Massive 3D VSP{reg_sign} and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that promise to take the gas industry to the next level in their quest for higher resolution images of deep and complex oil and gas reservoirs. Today only a fraction of the oil or gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of detailed compartmentalization of oil and gas reservoirs. In this project, we developed a 400 level 3C borehole seismic receiver array that allows for economic use of 3D borehole seismic imaging for reservoir characterization and monitoring. This new array has significantly increased the efficiency of recording large data volumes at sufficiently dense spatial sampling to resolve reservoir complexities. The receiver pods have been fabricated and tested to withstand high temperature (200 C/400 F) and high pressure (25,000 psi), so that they can operate in wells up to 7,620 meters (25,000 feet) deep. The receiver array is deployed on standard production or drill tubing. In combination with 3C surface seismic or 3C borehole seismic sources, the 400

  18. Reservoir management

    International Nuclear Information System (INIS)

    Satter, A.; Varnon, J.E.; Hoang, M.T.


    A reservoir's life begins with exploration leading to discovery followed by delineation of the reservoir, development of the field, production by primary, secondary and tertiary means, and finally to abandonment. Sound reservoir management is the key to maximizing economic operation of the reservoir throughout its entire life. Technological advances and rapidly increasing computer power are providing tools to better manage reservoirs and are increasing the gap between good and neutral reservoir management. The modern reservoir management process involves goal setting, planning, implementing, monitoring, evaluating, and revising plans. Setting a reservoir management strategy requires knowledge of the reservoir, availability of technology, and knowledge of the business, political, and environmental climate. Formulating a comprehensive management plan involves depletion and development strategies, data acquisition and analyses, geological and numerical model studies, production and reserves forecasts, facilities requirements, economic optimization, and management approval. This paper provides management, engineers geologists, geophysicists, and field operations staff with a better understanding of the practical approach to reservoir management using a multidisciplinary, integrated team approach

  19. Ocean basin volume constraints on global sea level since the Jurassic (United States)

    Seton, M.; Müller, R. D.


    Changes in the volume of the ocean basins, predominately via changes in the age-area distribution of oceanic lithosphere, have been suggested as the main driver for long-term eustatic sea-level change. As ocean lithosphere cools and thickens, ocean depth increases. The balance between the abundance of hot and buoyant crust along mid ocean ridges relative to abyssal plains is the primary driving force of long-term sea level changes. The emplacement of volcanic plateaus and chains as well as sedimentation contribute to raising eustatic sea level. Quantifying the average ocean basin depth through time primarily relies on the present day preserved seafloor spreading record, an analysis of the spatio-temporal record of plate boundary processes recorded on the continental margins adjacent to ocean basins as well as a consideration of the rules of plate tectonics, to reconstruct the history of seafloor spreading in the oceanic basins through time. This approach has been successfully applied to predict the magnitude and pattern of eustatic sea-level change since the Cretaceous (Müller et. al. 2008) but uncertainties in reconstructing mid ocean ridges and flanks increase back through time, given that we mainly depend on information preserved in preserved ocean crust. We have reconstructed the age-area distribution of oceanic lithosphere and the plate boundary configurations back to the Jurassic (200 Ma) in order to assess long-term sea-level change from amalgamation to dispersal of Pangaea. We follow the methodology presented in Müller et. al. (2008) but incorporate a new absolute plate motion model derived from Steinberger and Torsvik (2008) prior to 100 Ma, a merged Wessel et. al. (2006) and Wessel and Kroenke (2008) fixed Pacific hotspot reference frame, and a revised model for the formation of Panthalassa and the Cretaceous Pacific. Importantly, we incorporate a model for the break-up of the Ontong Java-Manihiki-Hikurangi plateaus between 120-86 Ma. We extend a

  20. Low-level radioactive waste from commercial nuclear reactors. Volume 2. Treatment, storage, disposal, and transportation technologies and constraints

    Energy Technology Data Exchange (ETDEWEB)

    Jolley, R.L.; Dole, L.R.; Godbee, H.W.; Kibbey, A.H.; Oyen, L.C.; Robinson, S.M.; Rodgers, B.R.; Tucker, R.F. Jr.


    The overall task of this program was to provide an assessment of currently available technology for treating commercial low-level radioactive waste (LLRW), to initiate development of a methodology for choosing one technology for a given application, and to identify research needed to improve current treatment techniques and decision methodology. The resulting report is issued in four volumes. Volume 2 discusses the definition, forms, and sources of LLRW; regulatory constraints affecting treatment, storage, transportation, and disposal; current technologies used for treatment, packaging, storage, transportation, and disposal; and the development of a matrix relating treatment technology to the LLRW stream as an aid for choosing methods for treating the waste. Detailed discussions are presented for most LLRW treatment methods, such as aqueous processes (e.g., filtration, ion exchange); dewatering (e.g., evaporation, centrifugation); sorting/segregation; mechanical treatment (e.g., shredding, baling, compaction); thermal processes (e.g., incineration, vitrification); solidification (e.g., cement, asphalt); and biological treatment.

  1. Low-level radioactive waste from commercial nuclear reactors. Volume 2. Treatment, storage, disposal, and transportation technologies and constraints

    International Nuclear Information System (INIS)

    Jolley, R.L.; Dole, L.R.; Godbee, H.W.; Kibbey, A.H.; Oyen, L.C.; Robinson, S.M.; Rodgers, B.R.; Tucker, R.F. Jr.


    The overall task of this program was to provide an assessment of currently available technology for treating commercial low-level radioactive waste (LLRW), to initiate development of a methodology for choosing one technology for a given application, and to identify research needed to improve current treatment techniques and decision methodology. The resulting report is issued in four volumes. Volume 2 discusses the definition, forms, and sources of LLRW; regulatory constraints affecting treatment, storage, transportation, and disposal; current technologies used for treatment, packaging, storage, transportation, and disposal; and the development of a matrix relating treatment technology to the LLRW stream as an aid for choosing methods for treating the waste. Detailed discussions are presented for most LLRW treatment methods, such as aqueous processes (e.g., filtration, ion exchange); dewatering (e.g., evaporation, centrifugation); sorting/segregation; mechanical treatment (e.g., shredding, baling, compaction); thermal processes (e.g., incineration, vitrification); solidification (e.g., cement, asphalt); and biological treatment

  2. Cesium accumulation by aquatic organisms at different trophic levels following an experimental release into a small reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Pinder, J.E., E-mail: jepinder@uga.ed [Savannah River Ecology Laboratory, P. O. Drawer E, Aiken, SC 29802 (United States); Hinton, T.G., E-mail: thomas.hinton@irsn.f [Savannah River Ecology Laboratory, P. O. Drawer E, Aiken, SC 29802 (United States); Taylor, B.E., E-mail: [Savannah River Ecology Laboratory, P. O. Drawer E, Aiken, SC 29802 (United States); Whicker, F.W., E-mail: ward.whicker@colostate.ed [Department of Environmental and Radiological Health Sciences, Colorado, State University, Fort Collins, CO 80523-1618 (United States)


    The rates of accumulation and subsequent loss of stable cesium ({sup 133}Cs) by organisms at different trophic levels within plankton-based and periphyton-based food chains were measured following the addition of {sup 133}Cs into a small reservoir near Aiken, South Carolina, USA. An uptake parameter u (L kg{sup -1} d{sup -1} dry mass) and a loss rate parameter k (d{sup -1}) were estimated for each organism using time-series measurements of {sup 133}Cs concentrations in water and biota, and these parameters were used to estimate maximum concentrations, times to maximum concentrations, and concentration ratios (C{sub r}). The maximum {sup 133}Cs concentrations for plankton, periphyton, the insect larva Chaoborus punctipennis, which feeds on plankton, and the snail Helisoma trivolvis, which feeds on periphyton, occurred within the first 14 days following the addition, whereas the maximum concentrations for the fish species Lepomis macrochirus and Micropterus salmoides occurred after 170 days. The C{sub r} based on dry mass for plankton and C. punctipennis were 1220 L kg{sup -1} and 5570 L kg{sup -1}, respectively, and were less than the C{sub r} of 8630 L kg{sup -1} for periphyton and 47,700 L kg{sup -1} for H. trivolvis. Although the C{sub r} differed between plankton-based and periphyton-based food chains, they displayed similar levels of biomagnification. Biomagnification was also indicated for fish where the C{sub r} for the mostly nonpiscivorous L. macrochirus of 22,600 L kg{sup -1} was three times less than that for mostly piscivorous M. salmoides of 71,500 L kg{sup -1}. Although the C{sub r} for M. salmoides was greater than those for periphyton and H. trivolvis, the maximum {sup 133}Cs concentrations for periphyton and H. trivolvis were greater than that for M. salmoides. - Research highlights: {yields} A simple uptake and loss model described the Cs dynamics in all the various biota. {yields} Concentrations of Cs were greater in periphyton than in plankton

  3. Constraints on sea level during the Pliocene: Records from the deep Pacific Ocean (United States)

    Woodard, S. C.; Rosenthal, Y.; Miller, K. G.; Wright, J. D.; Chiu, B. K.


    To reconstruct sea level during the transition from peak late Pliocene warmth (~3.15 Ma) to the onset of N. Hemisphere glaciation (~2.75 Ma), we generated high resolution stable isotope (δ18O, δ13C) and trace metal (Mg/Ca) records using benthic foraminifera, Uvigerina sp., from northwest Pacific ODP Site 1208 (3350 m water depth). During the peak late Pliocene warmth Mg/Ca-derived temperature records indicate deep Pacific interglacial temperatures were not significantly warmer (+0.6 ×0.8°C) than modern and glacial temperatures were near freezing similar to the LGM. In contrast, the deep N. Atlantic (Site 607) was apparently ~3°C warmer than the modern during both Pliocene glacial and interglacial periods (Sosdian and Rosenthal, 2009), based on the Mg/Ca of P. wuellerstorfi, which may be influenced by carbonate ion effect (Elderfield et al., 2009 and refs therein). δ18O records indicate a significant long-term increase in benthic δ18O in both the N. Atlantic and N. Pacific, although the rate of increase (Δδ18O) in the N. Atlantic is approximately 3x that of the N. Pacific (Site 1208), based on least squares regressions of all glacial-interglacial data. The discrepancy in the Δδ18O between the two basins is explained by Mg/Ca-derived temperature records. Results from Site 1208 show that the deep Pacific experienced no long-term cooling over the period 3.15-2.7 Ma when the deep N. Atlantic cooled by ~2.5°C on average. The relatively stable Pacific deep-water record provides the more reliable reconstructions of sea-level changes. From 3.15-2.7 Ma, Pacific δ18O data records an average increase of ~0.19× 0.08 per mil implying a sea level drop of 19 m × 8 m. After correcting the N. Atlantic record for temperature, we find the long term δ18O change from 3.15-2.7 Ma is ~0.23×0.1 per mil which equates to a peak of 23 m × 10 m. Our estimates are further corroborated by foraminiferal calcite δ18O recorded during Pliocene peak interglacials KM3 and G17. The

  4. Monitoring Water Surface and Level of a Reservoir Using Different Remote Sensing Approaches and Comparison with Dam Displacements Evaluated via GNSS

    Directory of Open Access Journals (Sweden)

    Claudia Pipitone


    Full Text Available Remote sensing allowed monitoring the reservoir water level by estimating its surface extension. Surface extension has been estimated using different approaches, employing both optical (Landsat 5 TM, Landsat 7 ETM+ SLC-Off, Landsat 8 OLI-TIRS and ASTER images and Synthetic Aperture Radar (SAR images (Cosmo SkyMed and TerraSAR-X. Images were characterized by different acquisition modes, geometric and spectral resolutions, allowing the evaluation of alternative and/or complementary techniques. For each kind of image, two techniques have been tested: The first based on an unsupervised classification and suitable to automate the process, the second based on visual matching with contour lines with the aim of fully exploiting the dataset. Their performances were evaluated by comparison with water levels measured in situ (r2 = 0.97 using the unsupervised classification, r2 = 0.95 using visual matching demonstrating that both techniques are suitable to quantify reservoir surface extension. However ~90% of available images were analyzed using the visual matching method, and just 37 images out of 58 using the other method. The evaluation of the water level from the water surface, using both techniques, could be easily extended to un-gauged reservoirs to manage the variations of the levels during normal operation. In addition, during the period of investigation, the use of Global Navigation Satellite System (GNSS allowed the estimation of dam displacements. The advantage of using as reference a GNSS permanent station positioned relatively far from the dam, allowed the exclusion of any interaction with the site deformations. By comparing results from both techniques, relationships between the orthogonal displacement component via GNSS, estimated water levels via remote sensing and in situ measurements were investigated. During periods of changing water level (April 2011–September 2011 and October 2011–March 2012, the moving average of displacement time

  5. A periodic review integrated inventory model with controllable setup cost, imperfect items, and inspection errors under service level constraint (United States)

    Saga, R. S.; Jauhari, W. A.; Laksono, P. W.


    This paper presents an integrated inventory model which consists of single vendor and buyer. The buyer managed its inventory periodically and orders products from the vendor to satisfy the end customer’s demand, where the annual demand and the ordering cost were in the fuzzy environment. The buyer used a service level constraint instead of the stock-out cost term, so that the stock-out level per cycle was bounded. Then, the vendor produced and delivered products to the buyer. The vendor had a choice to commit an investment to reduce the setup cost. However, the vendor’s production process was imperfect, thus the lot delivered contained some defective products. Moreover, the buyer’s inspection process was not error-free since the inspector could be mistaken in categorizing the product’s quality. The objective was to find the optimum value for the review period, the setup cost, and the number of deliveries in one production cycle which might minimize the joint total cost. Furthermore, the algorithm and numerical example were provided to illustrate the application of the model.

  6. Preindustrial atmospheric ethane levels inferred from polar ice cores: A constraint on the geologic sources of atmospheric ethane and methane (United States)

    Nicewonger, Melinda R.; Verhulst, Kristal R.; Aydin, Murat; Saltzman, Eric S.


    Ethane levels were measured in air extracted from Greenland and Antarctic ice cores ranging in age from 994 to 1918 Common Era (C.E.) There is good temporal overlap between the two data sets from 1600 to 1750 C.E. with ethane levels stable at 397 ± 28 parts per trillion (ppt) (±2 standard error (s.e.)) over Greenland and 103 ± 9 ppt over Antarctica. The observed north/south interpolar ratio of ethane (3.9 ± 0.1, 1σ) implies considerably more ethane emissions in the Northern Hemisphere than in the Southern Hemisphere, suggesting geologic ethane sources contribute significantly to the preindustrial ethane budget. Box model simulations based on these data constrain the global geologic emissions of ethane to 2.2-3.5 Tg yr-1 and biomass burning emissions to 1.2-2.5 Tg yr-1 during the preindustrial era. The results suggest biomass burning emissions likely increased since the preindustrial period. Biomass burning and geologic outgassing are also sources of atmospheric methane. The results place constraints on preindustrial methane emissions from these sources.

  7. Comparable contributions of structural-functional constraints and expression level to the rate of protein sequence evolution

    Directory of Open Access Journals (Sweden)

    Koonin Eugene V


    Full Text Available Abstract Background Proteins show a broad range of evolutionary rates. Understanding the factors that are responsible for the characteristic rate of evolution of a given protein arguably is one of the major goals of evolutionary biology. A long-standing general assumption used to be that the evolution rate is, primarily, determined by the specific functional constraints that affect the given protein. These constrains were traditionally thought to depend both on the specific features of the protein's structure and its biological role. The advent of systems biology brought about new types of data, such as expression level and protein-protein interactions, and unexpectedly, a variety of correlations between protein evolution rate and these variables have been observed. The strongest connections by far were repeatedly seen between protein sequence evolution rate and the expression level of the respective gene. It has been hypothesized that this link is due to the selection for the robustness of the protein structure to mistranslation-induced misfolding that is particularly important for highly expressed proteins and is the dominant determinant of the sequence evolution rate. Results This work is an attempt to assess the relative contributions of protein domain structure and function, on the one hand, and expression level on the other hand, to the rate of sequence evolution. To this end, we performed a genome-wide analysis of the effect of the fusion of a pair of domains in multidomain proteins on the difference in the domain-specific evolutionary rates. The mistranslation-induced misfolding hypothesis would predict that, within multidomain proteins, fused domains, on average, should evolve at substantially closer rates than the same domains in different proteins because, within a mutlidomain protein, all domains are translated at the same rate. We performed a comprehensive comparison of the evolutionary rates of mammalian and plant protein domains

  8. Organic Matter Isotopic Analyses from Chukchi Sea Sediments: New Constraints on the Late Quaternary Sea Level History of Beringia (United States)

    Lundeen, Z.; Brigham-Grette, J.; Driscoll, N.; Keigwin, L.; Burns, S.; Petsch, S.


    Accurately defining the sea level history of Beringia since the Last Glacial Maximum has important implications for understanding local paleoclimate data, paleoceanography of the Arctic Basin, and the timing of human migration from Asia into North America. However, few constraints exist on the timing of post-glacial sea level transgression across the former land bridge. To address this data gap, a new investigation into the sea level history of Beringia and its effects on regional paleoclimate and paleoceanography was launched in the summer of 2002 during a cruise on the USCGC Healy in the Bering and Chukchi Seas. A transect of cores were collected across the continental shelf to record the flooding history associated with glacial termination after the LGM. Cores from > 60m modern water depth lack lithologic changes expected from a marine transgressive sequence. Instead, these sediments consist primarily of clay and silt, with only minor amounts of coarser material, reflecting offshore marine burial. However, abrupt changes in downcore density suggest that disconformities may exist, with Holocene and Late-Glacial muds overlying older marine clays from an earlier sea level high-stand. To confirm this possibility, three cores were selected for elemental and isotopic analysis of bulk sedimentary organic matter. Downcore variations in δ 13C, δ 15N, TOC, and C/N are being used to determine the relative contributions of marine and terrigenous organic matter to the sediments. These geochemical data are useful as indicators of proximity to shoreline, riverine organic matter delivery and diagenetic alteration. Together with radiocarbon ages from fossil mollusks, these data place minimum limiting ages on the post-glacial transgression at multiple water depths on the Chukchi Shelf.

  9. Reproduction, food dynamics and exploitation level of Oreochromis niloticus (Perciformes: Cichlidae from artisanal fisheries in Barra Bonita Reservoir, Brazil

    Directory of Open Access Journals (Sweden)

    José Luis Costa Novaes


    Full Text Available Nile tilapia (Oreochromis niloticus, which is exotic to South America, is the most common species caught in artisanal fisheries at the Barra Bonita Reservoir, Southeastern Brazil. This species is of great socioeconomic importance for the region and keeps active a population of about 500 fishers. In the present study we assess reproduction, food dynamics and level of exploitation of O. niloticus, caught by artisanal fisheries in the Barra Bonita Reservoir. Specimens were collected monthly, from July 2004-June 2005, and a total of 1 715 specimens were analyzed. Each specimen was examined to obtain biological and biometric data: standard length (cm, total weight (g, reproductive data (sex and stage of maturation, and stomach contents (empty, partly full, and full. We also estimated the sex ratio (by macroscopic observation of gonads, reproductive period (by ovarian development and seasonal average of gonadosomatic index in females, and feeding habits (by stomach contents. The possible relationship between abiotic factors and the reproductive period was statistically verified using Spearman’s Rank Correlation. The FiSAT (ELEFAN I package was used to assess growth parameters, mortality rates and to infer exploitation rate from standard length frequencies. The O. niloticus population had a sex ratio of 1.3:1 (M:F. Results indicated that ripe females were captured throughout the year, with a higher frequency during the winter-2004 (with a frequency of 59%, at a mean temperature of 20.5°C, and in spring-2004 (with a frequency of 60.5% at a mean temperature of 21.18°C. The GSI mean values obtained by season were: winter-2004: 1.71; spring-2004: 1.72; summer-2005: 0.80, and autumn-2005: 1.19. The Spearman correlation indicated positive values with respect to pH, dissolved oxygen, electric conductivity, transparency and chlorophyll a, and negative values with respect to temperature, accumulated rainfall and altimetric benchmark. The main food items

  10. Constraint Differentiation

    DEFF Research Database (Denmark)

    Mödersheim, Sebastian Alexander; Basin, David; Viganò, Luca


    We introduce constraint differentiation, a powerful technique for reducing search when model-checking security protocols using constraint-based methods. Constraint differentiation works by eliminating certain kinds of redundancies that arise in the search space when using constraints to represent...... results show that constraint differentiation substantially reduces search and considerably improves the performance of OFMC, enabling its application to a wider class of problems....

  11. Determining the Probability of Violating Upper-Level Wind Constraints for the Launch of Minuteman Ill Ballistic Missiles At Vandenberg Air Force Base (United States)

    Shafer, Jaclyn A.; Brock, Tyler M.


    The 30th Operational Support Squadron Weather Flight (30 OSSWF) provides comprehensive weather services to the space program at Vandenberg Air Force Base (VAFB) in California. One of their responsibilities is to monitor upper-level winds to ensure safe launch operations of the Minuteman Ill ballistic missile. The 30 OSSWF requested the Applied Meteorology Unit (AMU) analyze VAFB sounding data to determine the probability of violating (PoV) upper-level thresholds for wind speed and shear constraints specific to this launch vehicle, and to develop a graphical user interface (GUI) that will calculate the PoV of each constraint on the day of launch. The AMU suggested also including forecast sounding data from the Rapid Refresh (RAP) model. This would provide further insight for the launch weather officers (LWOs) when determining if a wind constraint violation will occur over the next few hours, and help to improve the overall upper winds forecast on launch day.

  12. [Distribution and risk assessment of mercury species in soil of the water-level-fluctuating zone in the Three Gorges Reservoir]. (United States)

    Zhang, Cheng; Chen, Hong; Wang, Ding-Yong; Sun, Rong-Guo; Zhang, Jin-Yang


    To investigate pollution level and ecological risk of mercury in soils of the water-level-fluctuating zone in the Three Gorges Reservoir Region, 192 surface soil samples from 14 counties (districts) in Chongqing were obtained. Concentrations of THg and Hg species, bioavailable Hg were analyzed and discussed. Geoaccumulation index (I(geo)) and Håkanson potential ecological risk index (E(r)) were applied to assess the pollution status and potential ecological risk of THg and Hg species, respectively. The results showed that significant differences in the concentration of THg were found in soils of water-level-fluctuating zone in the Three Gorges Reservoir. The THg concentration ranged from 22.4 to 393.5 microg x kg(-1), with an average of (84.2 +/- 54.3) microg x kg(-1). 76.6% of the samples' THg content was higher than the soil background value in the Three Gorges Reservoir Region. The percentage of five mercury species (water-soluble Hg, HCl-soluble Hg, KOH-soluble Hg, H2O2-soluble Hg, residue Hg) in soils were 4.1%, 15.5%, 18.3%, 10.9%, 51.3%, respectively. The average concentrations of bioavailable mercury varied between 19.7-36.6 microg x kg(-1), and the percentage of bioavailable Hg was 22.1%-51.6% of THg. According to the geoaccumulation index, the soils were lightly polluted by Hg. Håkanson single potential ecological risk index evaluation showed that Hg species had a low potential ecological risk, moreover, soils of water-level-fluctuating zone in the Three Gorges Reservoir were at low ecological risk levels as evaluated by bioavailable Hg. While, the assessment results based on THg of soils was much higher than that based on the Hg species. Two methods of evaluation showed that the I(geo) and E(r) values calculated based on the Hg species better reflected the actual pollution levels of soils and its hazard to aquatic organisms.

  13. Stoichiometric Representation of Gene–Protein–Reaction Associations Leverages Constraint-Based Analysis from Reaction to Gene-Level Phenotype Prediction

    DEFF Research Database (Denmark)

    Machado, Daniel; Herrgard, Markus; Rocha, Isabel


    level by explicitly accounting for the individual fluxes of enzymes (and subunits) encoded by each gene. We show how this can be applied to different kinds of constraint-based analysis: flux distribution prediction, gene essentiality analysis, random flux sampling, elementary mode analysis...

  14. Material Weakening of Slip Zone Soils Induced by Water Level Fluctuation in the Ancient Landslides of Three Gorges Reservoir

    Directory of Open Access Journals (Sweden)

    Yu-Yong Jiao


    Full Text Available This experimental study investigated the effect of repeated wetting and drying on the reduction of slip zone soils taken from the Huangtupo landslide in the Three Gorges Reservoir, China. The variation process of the physical property and substance composition of the slip zone soils under the wetting-drying cycles was studied through liquid and plastic limit test and X-ray diffraction test. The results indicate that (1 the shearing strength of the slip zone soil dramatically decreased after one wetting-drying cycle and then gradually decreased until reaching a relatively stable state at the fourth cycle; (2 the plasticity index of the slip zone soil varied with increasing number of cycles and a variation process opposite to that of the strength value was observed; and (3 the clay mineral content in the slip zone soil increased and the calcite and quartz contents relatively decreased with increasing number of cycles. The variations in the plasticity index of the slip zone soil, as well as the increase in its clay mineral content, play important roles in the strength reduction. The results of this study provide a foundation for revealing the deformation and damage mechanism of landslides in reservoir banks.

  15. Renewable Energy Prices in State-Level Feed-in Tariffs. Federal Law Constraints and Possible Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Hempling, Scott [National Regulatory Research Inst., Silver Spring, MD (United States); Elefant, Carolyn [Law Offices of Carolyn Elefant, Washington, DC (United States); Cory, Karlynn [National Renewable Energy Lab. (NREL), Golden, CO (United States); Porter, Kevin [Exeter Associates, Inc., Golden, CO (United States)


    This report details how state feed-in tariff (FIT) programs can be legally implemented and how they can comply with federal requirements. The report describes the federal constraints on FIT programs and identifies legal methods that are free of those constrains.

  16. Trace Metal Levels in Rainbow Trout (Oncorhynchus mykiss) Cultured in Net Cages in a Reservoir and Evaluation of Human Health Risks from Consumption. (United States)

    Varol, Memet; Kaya, Gülderen Kurt; Alp, Sumru Anık; Sünbül, Muhammet Raşit


    Although fish consumption has positive health effects, metals accumulated in fish can cause human health risks. In this study, the levels of ten metals in rainbow trout (Oncorhynchus mykiss) farmed in the Keban Dam Reservoir, which has the biggest rainbow trout production capacity in Turkey, were determined and compared with the maximum permissible levels (MPLs). Also, human health risks associated with rainbow trout consumption were assessed. The metal concentrations in rainbow trout were found below the MPLs. The estimated daily intake of each metal was much lower than the respective tolerable daily intake. The target hazard quotient (THQ) for individual metal and total THQ for combined metals did not exceed 1, indicating no health risk for consumers. The cancer risk (CR) value for inorganic arsenic was within the acceptable lifetime risk range of 10 -6 and 10 -4 . For carcinogenic and non-carcinogenic effects, the maximum allowable fish consumption rates were high enough to ensure the human health. According to these results, the consumption of rainbow trout farmed in the Keban Dam Reservoir does not pose a risk on human health.

  17. Response of soil physico-chemical properties to restoration approaches and submergence in the water level fluctuation zone of the Danjiangkou Reservoir, China. (United States)

    Shu, Xiao; Zhang, KeRong; Zhang, QuanFa; Wang, WeiBo


    With the completion of the Danjiangkou Dam, the impoundment and drainage of dams can significantly alter shorelines, hydrological regime, and sediment and can result in the loss of soil and original riparian vegetation. Revegetation may affect soil properties and have broad important implications both for ecological services and soil recovery. In this work, we investigated the soil properties under different restoration approaches, and before and after submergence in the water level fluctuation zone (WLFZ) of the Danjiangkou Reservoir. Soil physical (bulk density and soil moisture), chemical (pH, soil organic carbon, nitrogen, phosphorus and potassium contents), and heavy metals were determined. This study reported that restoration approaches have impacts on soil moisture, pH, N, soil organic carbon, P, K and heavy metals in the WLFZ of the Danjiangkou Reservoir. Our results indicated that different restoration approaches could increase the soil moisture while decrease soil pH. Higher soil organic carbon in propagule banks transplantation (PBT) and shrubs restoration (SR) indicate that PBT and SR may provide soil organic matter more quickly than trees restoration (TR). SR and TR could significantly improve the soil total P and available P. PBT and SR could improve the soil total K and available K. SR and TR could significantly promote Cu and Zn adsorption, and Pb and Fe release by plant. Submergence could significantly affect the soil pH, NO 3 - -N, NH 4 + -N, total P and available P. Submergence could promote NO 3 - -N and available P adsorption, and NH 4 + -N and total P release by soil. The soil quality index (SQI) values implied that TR and PBT greatly improved soil quality. The present study suggests that PBT and TR could be effective for soil restoration in WLFZ of the Danjiangkou Reservoir. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. How the fluctuations of water levels affect populations of invasive bivalve Corbicula fluminea (Müller, 1774) in a Neotropical reservoir? (United States)

    Paschoal, L R P; Andrade, D P; Darrigran, G


    Corbicula fluminea is an invasive bivalve responsible for several environmental and financial problems around the globe. Despite the invasive potential of this species, it suffers certain restrictions in lentic environments due to natural phenomena that significantly affect its population structure (e.g. water column fluctuation and sunlight exposure). The present study addresses how temporal decline of the water level in a Neotropical reservoir and exposure to sunlight affect the population structure of C. fluminea. Samplings were carried out twice in the reservoir of Furnas Hydroelectric Power Station (HPS) (Minas Gerais, Brazil), in 2011 and 2012. Population density, spatial distribution and mean shell length of C. fluminea were estimated for each year after sampling in 51 quadrats (0.0625m2) placed on three transects at different distances along the reservoir margins (0, 10 and 20 m from a fixed-point). We observed a predominance of C. fluminea in both years, with a simultaneous gradual decrease in density and richness of native species in the sampling area. Significant differences in density of C. fluminea were registered at different distances from the margin, and are related to the temporal variability of physical conditions of the sediment and water in these environments. We also registered a trend toward an increase in the density and aggregation of C. fluminea as we moved away from the margin, due to the greater stability of these areas (>10 m). The mean shell length of C. fluminea showed significant difference between the distinct distances from the margin and during the years, as well as the interaction of these factors (Distances vs.Years). These results were associated with the reproductive and invasive capacity of this species. This study reveals that these temporal events (especially water column fluctuation) may cause alterations in density, spatial distribution and mean shell length of C. fluminea and the composition of the native malacofauna in

  19. How the fluctuations of water levels affect populations of invasive bivalve Corbicula fluminea (Müller, 1774 in a Neotropical reservoir?

    Directory of Open Access Journals (Sweden)

    LRP. Paschoal

    Full Text Available Corbicula fluminea is an invasive bivalve responsible for several environmental and financial problems around the globe. Despite the invasive potential of this species, it suffers certain restrictions in lentic environments due to natural phenomena that significantly affect its population structure (e.g. water column fluctuation and sunlight exposure. The present study addresses how temporal decline of the water level in a Neotropical reservoir and exposure to sunlight affect the population structure of C. fluminea. Samplings were carried out twice in the reservoir of Furnas Hydroelectric Power Station (HPS (Minas Gerais, Brazil, in 2011 and 2012. Population density, spatial distribution and mean shell length of C. fluminea were estimated for each year after sampling in 51 quadrats (0.0625m2 placed on three transects at different distances along the reservoir margins (0, 10 and 20 m from a fixed-point. We observed a predominance of C. fluminea in both years, with a simultaneous gradual decrease in density and richness of native species in the sampling area. Significant differences in density of C. fluminea were registered at different distances from the margin, and are related to the temporal variability of physical conditions of the sediment and water in these environments. We also registered a trend toward an increase in the density and aggregation of C. fluminea as we moved away from the margin, due to the greater stability of these areas (>10 m. The mean shell length of C. fluminea showed significant difference between the distinct distances from the margin and during the years, as well as the interaction of these factors (Distances vs.Years. These results were associated with the reproductive and invasive capacity of this species. This study reveals that these temporal events (especially water column fluctuation may cause alterations in density, spatial distribution and mean shell length of C. fluminea and the composition of the native

  20. Enhanced characterization of reservoir hydrocarbon components using electromagnetic data attributes

    KAUST Repository

    Katterbauer, Klemens


    Advances in electromagnetic imaging techniques have led to the growing utilization of this technology for reservoir monitoring and exploration. These exploit the strong conductivity contrast between the hydrocarbon and water phases and have been used for mapping water front propagation in hydrocarbon reservoirs and enhancing the characterization of the reservoir formation. The conventional approach for the integration of electromagnetic data is to invert the data for saturation properties and then subsequently use the inverted properties as constraints in the history matching process. The non-uniqueness and measurement errors may however make this electromagnetic inversion problem strongly ill-posed, leading to potentially inaccurate saturation profiles. Another limitation of this approach is the uncertainty of Archie\\'s parameters in relating rock conductivity to water saturation, which may vary in the reservoir and are generally poorly known. We present an Ensemble Kalman Filter framework for efficiently integrating electromagnetic data into the history matching process and for simultaneously estimating the Archie\\'s parameters and the variance of the observation error of the electromagnetic data. We apply the proposed framework to a compositional reservoir model. We aim at assessing the relevance of EM data for estimating the different hydrocarbon components of the reservoir. The experimental results demonstrate that the individual hydrocarbon components are generally well matched, with nitrogen exhibiting the strongest improvement. The estimated observation error standard deviations are also within expected levels (between 5 and 10%), significantly contributing to the robustness of the proposed EM history matching framework. Archie\\'s parameter estimates approximate well the reference profile and assist in the accurate description of the electrical conductivity properties of the reservoir formation, hence leading to estimation accuracy improvements of around

  1. Food web (bio-)manipulation of South African reservoirs – viable ...

    African Journals Online (AJOL)


    Oct 4, 2006 ... consequences in local reservoirs, although conversely, these are offset by suspended-clay turbidity. ... Keywords: eutrophication, management constraints and options, warm-water reservoirs, biomanipulation, research needs. Introduction ... a collective term to include both conventional algae (photosyn-.

  2. On the successful use of a simplified model to simulate the succession of toxic cyanobacteria in a hypereutrophic reservoir with a highly fluctuating water level. (United States)

    Fadel, Ali; Lemaire, Bruno J; Vinçon-Leite, Brigitte; Atoui, Ali; Slim, Kamal; Tassin, Bruno


    Many freshwater bodies worldwide that suffer from harmful algal blooms would benefit for their management from a simple ecological model that requires few field data, e.g. for early warning systems. Beyond a certain degree, adding processes to ecological models can reduce model predictive capabilities. In this work, we assess whether a simple ecological model without nutrients is able to describe the succession of cyanobacterial blooms of different species in a hypereutrophic reservoir and help understand the factors that determine these blooms. In our study site, Karaoun Reservoir, Lebanon, cyanobacteria Aphanizomenon ovalisporum and Microcystis aeruginosa alternatively bloom. A simple configuration of the model DYRESM-CAEDYM was used; both cyanobacteria were simulated, with constant vertical migration velocity for A. ovalisporum, with vertical migration velocity dependent on light for M. aeruginosa and with growth limited by light and temperature and not by nutrients for both species. The model was calibrated on two successive years with contrasted bloom patterns and high variations in water level. It was able to reproduce the measurements; it showed a good performance for the water level (root-mean-square error (RMSE) lower than 1 m, annual variation of 25 m), water temperature profiles (RMSE of 0.22-1.41 °C, range 13-28 °C) and cyanobacteria biomass (RMSE of 1-57 μg Chl a L -1 , range 0-206 μg Chl a L -1 ). The model also helped understand the succession of blooms in both years. The model results suggest that the higher growth rate of M. aeruginosa during favourable temperature and light conditions allowed it to outgrow A. ovalisporum. Our results show that simple model configurations can be sufficient not only for theoretical works when few major processes can be identified but also for operational applications. This approach could be transposed on other hypereutrophic lakes and reservoirs to describe the competition between dominant phytoplankton

  3. Reservoir characterization of Pennsylvanian Sandstone Reservoirs. Annual report

    Energy Technology Data Exchange (ETDEWEB)

    Kelkar, M.


    This annual report describes the progress during the second year of a project on Reservoir Characterization of Pennsylvanian Sandstone Reservoirs. The report is divided into three sections: (i) reservoir description and scale-up procedures; (ii) outcrop investigation; (iii) in-fill drilling potential. The first section describes the methods by which a reservoir can be characterized, can be described in three dimensions, and can be scaled up with respect to its properties, appropriate for simulation purposes. The second section describes the progress on investigation of an outcrop. The outcrop is an analog of Bartlesville Sandstone. We have drilled ten wells behind the outcrop and collected extensive log and core data. The cores have been slabbed, photographed and the several plugs have been taken. In addition, minipermeameter is used to measure permeabilities on the core surface at six inch intervals. The plugs have been analyzed for the permeability and porosity values. The variations in property values will be tied to the geological descriptions as well as the subsurface data collected from the Glen Pool field. The third section discusses the application of geostatistical techniques to infer in-fill well locations. The geostatistical technique used is the simulated annealing technique because of its flexibility. One of the important reservoir data is the production data. Use of production data will allow us to define the reservoir continuities, which may in turn, determine the in-fill well locations. The proposed technique allows us to incorporate some of the production data as constraints in the reservoir descriptions. The technique has been validated by comparing the results with numerical simulations.

  4. [Mercury dynamics of several plants collected from the water-level fluctuation zone of the Three Gorges Reservoir area during flooding and its impact on water body]. (United States)

    Zhang, Xiang; Zhang, Cheng; Sun, Rong-guo; Wang, Ding-yong


    Submerged plants are a major source for the abnormal elevation of methylmercury in reservoir. Several specific plants (Echinochloa crusgalli, Cynodondactylon and Corn stover) were collected and inundated in a simulated aquatic environment in the laboratory for investigating the mercury (Hg) dynamics in plants and the release process into water, aiming to find out the properties of Hg dynamics of plants under inundation conditions and its impact on water body in the Water-Level Fluctuation Zone of the Three Gorges Reservoir Area. The results showed that the contents of total mercury in several plants were in the range of 9. 21-12.07 ng x g(-1), and the percentage content of methylmercury (MeHg) was about 1%-2%. The content of total mercury (THg) in plants gradually decreased, by 35.81%-55.96%, whereas that of the dissolved mercury (DHg) increased sharply, by 103.23% -232.15%, which indicated an emission of Hg from plants to water in the process of decomposition. Furthermore, the state of inundation provided sufficient conditions for the methylation process in plants and therefore caused an increase of the content of methylmercury in the plant residues, which was 3.04-6.63 times as much as the initial content. The concentration of dissolved methylmercury (DMeHg) in the overlying water also increased significantly by 14.84- 16.05 times compared with the initial concentration. Meanwhile, the concentration of dissolved oxygen (DO) in the overlying water was significantly and negatively correlated with DMeHg. On the other hand, the concentration of dissolved organic carbon (DOC) in the overlying water was significantly and positively correlated with DMeHg. During the whole inundation period, the increase of DHg in the overlying water accounted for 41.74% -47.01% of the total amount of THg emission, and there was a negative correlation between the content of THg in plant residues and that of DHg in the overlying water.

  5. An integrated production-inventory model for the singlevendor two-buyer problem with partial backorder, stochastic demand, and service level constraints (United States)

    Arfawi Kurdhi, Nughthoh; Adi Diwiryo, Toray; Sutanto


    This paper presents an integrated single-vendor two-buyer production-inventory model with stochastic demand and service level constraints. Shortage is permitted in the model, and partial backordered partial lost sale. The lead time demand is assumed follows a normal distribution and the lead time can be reduced by adding crashing cost. The lead time and ordering cost reductions are interdependent with logaritmic function relationship. A service level constraint policy corresponding to each buyer is considered in the model in order to limit the level of inventory shortages. The purpose of this research is to minimize joint total cost inventory model by finding the optimal order quantity, safety stock, lead time, and the number of lots delivered in one production run. The optimal production-inventory policy gained by the Lagrange method is shaped to account for the service level restrictions. Finally, a numerical example and effects of the key parameters are performed to illustrate the results of the proposed model.


    Cytochrome P4501A (CYP1A) levels in tissues of fish inhabiting polluted areas have been used extensively in biomonitoring studies in Europe and North America. However, little information is available about the extent of CYP1A expression in fish from South American waters, nor on ...

  7. Efficient Operation of a Multi-purpose Reservoir in Chile: Integration of Economic Water Value for Irrigation and Hydropower (United States)

    Olivares, M. A.; Gonzalez Cabrera, J. M., Sr.; Moreno, R.


    Operation of hydropower reservoirs in Chile is prescribed by an Independent Power System Operator. This study proposes a methodology that integrates power grid operations planning with basin-scale multi-use reservoir operations planning. The aim is to efficiently manage a multi-purpose reservoir, in which hydroelectric generation is competing with other water uses, most notably irrigation. Hydropower and irrigation are competing water uses due to a seasonality mismatch. Currently, the operation of multi-purpose reservoirs with substantial power capacity is prescribed as the result of a grid-wide cost-minimization model which takes irrigation requirements as constraints. We propose advancing in the economic co-optimization of reservoir water use for irrigation and hydropower at the basin level, by explicitly introducing the economic value of water for irrigation represented by a demand function for irrigation water. The proposed methodology uses the solution of a long-term grid-wide operations planning model, a stochastic dual dynamic program (SDDP), to obtain the marginal benefit function for water use in hydropower. This marginal benefit corresponds to the energy price in the power grid as a function of the water availability in the reservoir and the hydrologic scenarios. This function allows capture technical and economic aspects to the operation of hydropower reservoir in the power grid and is generated with the dual variable of the power-balance constraint, the optimal reservoir operation and the hydrologic scenarios used in SDDP. The economic value of water for irrigation and hydropower are then integrated into a basin scale stochastic dynamic program, from which stored water value functions are derived. These value functions are then used to re-optimize reservoir operations under several inflow scenarios.

  8. A periodic review integrated inventory model with controllable safety stock and setup cost under service level constraint and distribution-free demand (United States)

    Kurdhi, N. A.; Jamaluddin, A.; Jauhari, W. A.; Saputro, D. R. S.


    In this study, we consider a stochastic integrated manufacturer-retailer inventory model with service level constraint. The model analyzed in this article considers the situation in which the vendor and the buyer establish a long-term contract and strategic partnership to jointly determine the best strategy. The lead time and setup cost are assumed can be controlled by an additional crashing cost and an investment, respectively. It is assumed that shortages are allowed and partially backlogged on the buyer’s side, and that the protection interval (i.e., review period plus lead time) demand distribution is unknown but has given finite first and second moments. The objective is to apply the minmax distribution free approach to simultaneously optimize the review period, the lead time, the setup cost, the safety factor, and the number of deliveries in order to minimize the joint total expected annual cost. The service level constraint guarantees that the service level requirement can be satisfied at the worst case. By constructing Lagrange function, the analysis regarding the solution procedure is conducted, and a solution algorithm is then developed. Moreover, a numerical example and sensitivity analysis are given to illustrate the proposed model and to provide some observations and managerial implications.

  9. Optimizing Wind And Hydropower Generation Within Realistic Reservoir Operating Policy (United States)

    Magee, T. M.; Clement, M. A.; Zagona, E. A.


    Previous studies have evaluated the benefits of utilizing the flexibility of hydropower systems to balance the variability and uncertainty of wind generation. However, previous hydropower and wind coordination studies have simplified non-power constraints on reservoir systems. For example, some studies have only included hydropower constraints on minimum and maximum storage volumes and minimum and maximum plant discharges. The methodology presented here utilizes the pre-emptive linear goal programming optimization solver in RiverWare to model hydropower operations with a set of prioritized policy constraints and objectives based on realistic policies that govern the operation of actual hydropower systems, including licensing constraints, environmental constraints, water management and power objectives. This approach accounts for the fact that not all policy constraints are of equal importance. For example target environmental flow levels may not be satisfied if it would require violating license minimum or maximum storages (pool elevations), but environmental flow constraints will be satisfied before optimizing power generation. Additionally, this work not only models the economic value of energy from the combined hydropower and wind system, it also captures the economic value of ancillary services provided by the hydropower resources. It is recognized that the increased variability and uncertainty inherent with increased wind penetration levels requires an increase in ancillary services. In regions with liberalized markets for ancillary services, a significant portion of hydropower revenue can result from providing ancillary services. Thus, ancillary services should be accounted for when determining the total value of a hydropower system integrated with wind generation. This research shows that the end value of integrated hydropower and wind generation is dependent on a number of factors that can vary by location. Wind factors include wind penetration level

  10. The effect of water physical quality and water level changes on the occurrence and density of larvae of Anopheles mosquitoes around the shoreline of the Koka reservoir, Central Ethiopia (United States)

    Teklu, B. M.; Tekie, H.; McCartney, M.; Kibret, S.


    Entomological studies to determine the effect of the physical characteristics of larval breeding water bodies and reservoir water level changes on the occurrence of Anopheles mosquito larvae and on the spatial and temporal formation of larval breeding habitats were conducted in two villages at Koka reservoir between August and December 2007. Of the two study villages, Ejersa is in close proximity to the reservoir, and Kuma is 5 km away from it. Data on the type, number and physical characteristics of Anopheles larval breeding habitat, species composition and densities of anopheles mosquitoes in and around the study villages were investigated and recorded. Meteorological and reservoir water level data were compared with availability of Anopheles larval breeding sites and densities. Entomological data from the weekly larval collections showed that Anopheles pharoensis Theobald, Anopheles gambiae s.l. Giles, Anopheles coustani Laveran and Anopheles squamosus Theobald were breeding in the study area. The mean larval density of A. gambiae s.l. in this study was higher in slightly turbid and shallow aquatic habitats than in turbid and relatively deep aquatic habitats (F=16.97, plevels and the number of positive breeding habitats at Ejersa during the sampling period (r=0.605, pphysical characteristics such as water temperature, turbidity, depth and vegetation cover play an important role in the species composition, total Anopheles larval count, and the density of Anopheles mosquitoes in the vicinity. The proliferation of suitable breeding habitats around the reservoir villages is strongly associated with reservoir water level changes. This is particularly important for A. pharoensis and A. arabiensis which are important vectors of malaria in the area. Further investigation on the species diversity, physical and chemical habitat characteristics and impact of water holding capacity of the soil need to be done to generate detailed baseline data which will serve as a basis

  11. Modelling of Hydropower Reservoir Variables for Energy Generation ...

    African Journals Online (AJOL)

    Efficient management of hydropower reservoir can only be realized when there is sufficient understanding of interactions existing between reservoir variables and energy generation. Reservoir inflow, storage, reservoir elevation, turbine release, net generating had, plant use coefficient, tail race level and evaporation losses ...

  12. Hydrologic-energy balance constraints on the Holocene lake-level history of lake Titicaca, South America

    Energy Technology Data Exchange (ETDEWEB)

    Rowe, H.D.; Dunbar, R.B. [Stanford University, Geological and Environmental Sciences, Stanford, CA (United States)


    A basin-scale hydrologic-energy balance model that integrates modern climatological, hydrological, and hypsographic observations was developed for the modern Lake Titicaca watershed (northern Altiplano, South America) and operated under variable conditions to understand controls on post-glacial changes in lake level. The model simulates changes in five environmental variables (air temperature, cloud fraction, precipitation, relative humidity, and land surface albedo). Relatively small changes in three meteorological variables (mean annual precipitation, temperature, and/or cloud fraction) explain the large mid-Holocene lake-level decrease ({proportional_to}85 m) inferred from seismic reflection profiling and supported by sediment-based paleoproxies from lake sediments. Climatic controls that shape the present-day Altiplano and the sediment-based record of Holocene lake-level change are combined to interpret model-derived lake-level simulations in terms of changes in the mean state of ENSO and its impact on moisture transport to the Altiplano. (orig.)

  13. Hydrologic-energy balance constraints on the Holocene lake-level history of lake Titicaca, South America (United States)

    Rowe, H. D.; Dunbar, R. B.


    A basin-scale hydrologic-energy balance model that integrates modern climatological, hydrological, and hypsographic observations was developed for the modern Lake Titicaca watershed (northern Altiplano, South America) and operated under variable conditions to understand controls on post-glacial changes in lake level. The model simulates changes in five environmental variables (air temperature, cloud fraction, precipitation, relative humidity, and land surface albedo). Relatively small changes in three meteorological variables (mean annual precipitation, temperature, and/or cloud fraction) explain the large mid-Holocene lake-level decrease (˜85 m) inferred from seismic reflection profiling and supported by sediment-based paleoproxies from lake sediments. Climatic controls that shape the present-day Altiplano and the sediment-based record of Holocene lake-level change are combined to interpret model-derived lake-level simulations in terms of changes in the mean state of ENSO and its impact on moisture transport to the Altiplano.

  14. [Effects of Citric Acid on Activation and Methylation of Mercury in the Soils of Water-Level-Fluctuating Zone of the Three Gorges.Reservoir]. (United States)

    Qin, Cai-qing; Liang, Li; You, Rui; Deng, Han; Wang, Ding-yong


    To investigate effects of the main component of vegetation root exudates-citric acid on activation and methylation of mercury in the soil of water-level-fluctuating zone (WLFZ) of the Three Gorges Reservoir area, simulation experiments were conducted by extracting and cultivating soil with different concentrations of citric acid. The results showed that after adding citric acid, the total mercury content in leaching solution before reaching peak were higher than that of the control, and increased with the increase of citric acid concentrations. The maximum amount of mercury complexes increased initially and then reached plateaus with the percentage against the total mercury in soil of 1.03%, 1.67%, 1.99%, 2.47%, 2.68%, 2.73% and 2.73% for different citric acid concentrations (0, 1, 2, 4, 5, 6 and 8 mmol · L⁻¹). In addition, concentrations of methylmercury ( MeHg) in soil remained stable in the first 3 hours, and then increased accompanying with the increasing rate rising with the concentration of citric acid ( besides the control group) . This result indicated that citric acid probably could promote the transformation process from inorganic mercury to MeHg in soil. which increased with the concentration of citric acid.

  15. [Characteristics of dissolved organic carbon release under inundation from typical grass plants in the water-level fluctuation zone of the Three Gorges Reservoir area]. (United States)

    Tan, Qiu-Xia; Zhu, Boi; Hua, Ke-Ke


    The water-level fluctuation zone of the Three Gorges Reservoir (TGR) exposes in spring and summer, then, green plants especially herbaceous plants grow vigorously. In the late of September, water-level fluctuation zone of TGR goes to inundation. Meanwhile, annually accumulated biomass of plant will be submerged for decaying, resulting in organism decomposition and release a large amount of dissolved organic carbon (DOC). This may lead to negative impacts on water environment of TGR. The typical herbaceous plants from water-level fluctuation zone were collected and inundated in the laboratory for dynamic measurements of DOC concentration of overlying water. According to the determination, the DOC release rates and fluxes have been calculated. Results showed that the release process of DOC variation fitted in a parabolic curve. The peak DOC concentrations emerge averagely in the 15th day of inundation, indicating that DOC released quickly with organism decay of herbaceous plant. The release process of DOC could be described by the logarithm equation. There are significant differences between the concentration of DOC (the maximum DOC concentration is 486.88 mg x L(-1) +/- 35.97 mg x L(-1) for Centaurea picris, the minimum is 4.18 mg x L(-1) +/- 1.07 mg x L(-1) for Echinochloacrus galli) and the release amount of DOC (the maximum is 50.54 mg x g(-1) for Centaurea picris, the minimum is 6.51 mg x g(-1) for Polygonum hydropiper) due to different characteristics of plants, especially, the values of C/N of herbaceous plants. The cumulative DOC release quantities during the whole inundation period were significantly correlated with plants' C/N values in linear equations.

  16. Interaction of Technology Adoption Constraints and Multi-level Policy Coherence at the Energy-Food Nexus (United States)

    Gerst, M.; Cox, M. E.; Laser, M.; Locke, K. A.; Kapuscinski, A. R.


    Policy- and decision-making at the food-energy-water (FEW) nexus entails additional complexities due to the multi-objective nature of FEW socio-technical systems: policies and decisions meant to improve one facet of the nexus might be less beneficial, or even detrimental, to achieving goals for other facets. In addition, implementing policies and decisions may be more difficult due to increasing coordination required among stakeholders across each nexus facet. We highlight these issues in an economic, material/energy flow, and institutional assessment of dairy farms that produce power from anaerobic digestion of cow manure. This socio-technical system is an example of an integrated food-energy system (IFES), which co-produces food and energy. In the case of dairy farms, water is also a significant consideration because cow manure, if improperly managed, can negatively impact water bodies. Our assessment asks the questions (i) of whether or not adopting an IFES improves farm resilience under potential economic and environment futures and (ii) how decisions, policies, and information can best be tailored to the FEW nexus. Our study consists of semi-structured interviews of 60 farms split between the US states of New York and Vermont, both of which have enacted policies to encourage digester adoption. Each interview asks farmers about their material and energy flows, costs, and decision-making process for adopting (or not) an anaerobic digester. In addition, farmers are asked questions about challenges and barriers they might have faced and future drivers of change. Preliminary results highlight important interactions between policy and decision-making. Foremost, an analysis of policy cohesion shows that environmental objectives cross sectors and governance levels, as state-level greenhouse gas mitigation policies interact with federal-level nutrient management policies. This form of potential policy incoherence may introduce additional problems that hinder digester

  17. The constraints

    International Nuclear Information System (INIS)

    Jones, P.M.S.


    There are considerable incentives for the use of nuclear in preference to other sources for base load electricity generation in most of the developed world. These are economic, strategic, environmental and climatic. However, there are two potential constraints which could hinder the development of nuclear power to its full economic potential. These are public opinion and financial regulations which distort the nuclear economic advantage. The concerns of the anti-nuclear lobby are over safety, (especially following the Chernobyl accident), the management of radioactive waste, the potential effects of large scale exposure of the population to radiation and weapons proliferation. These are discussed. The financial constraint is over two factors, the availability of funds and the perception of cost, both of which are discussed. (U.K.)

  18. Low-level radioactive waste from commercial nuclear reactors. Volume 3. Bibliographic abstracts of significant source references. Part 2. Bibliography for treatment, storage, disposal and transportation regulatory constraints

    Energy Technology Data Exchange (ETDEWEB)

    Jolley, R.L.; Rodgers, B.R.


    The overall task of this program was to provide an assessment of currently available technology for treating commercial low-level radioactive waste (LLRW), to initiate development of a methodology for choosing one technology for a given application, and to identify research needed to improve current treatment techniques and decision methodology. The resulting report is issued in four volumes. Volume 3 of this series is a collection of abstracts of most of the reference documents used for this study. Because of the large volume of literature, the abstracts have been printed in two separate parts. Federal, state, and local regulations affect the decision process for selecting technology applications. Regulations may favor a particular technology and may prevent application of others. Volume 3, part 2 presents abstracts of the regulatory constraint documents that relate to all phases of LLRW management (e.g., treatment, packaging, storage, transportation, and disposal).

  19. Economic Design of Multi-echelon Inventory System with Variable Lead Time and Service Level Constraint in a Fuzzy Cost Environment

    Directory of Open Access Journals (Sweden)

    S. Priyan


    Full Text Available Normally, human based industrial decision making involves both quantitative and qualitative input factors such as ordering cost, setup cost, etc. Thus the practitioners should be careful in accounting flexibility in the input factors. This paper optimizes an inventory system by employing mathematical model with variable lead time and service level constraint (SLC in a fuzzy cost environment. Fuzziness is established by allowing the cost components imprecise and vague to certain extent. Trapezoidal and triangular fuzzy numbers are used to represent these characteristics. We also use signed distance method to defuzzify the fuzzy joint total expected cost and differential calculus optimization technique is adopted to find all optimal solutions to the model. Numerical results highlighting the sensitivity in the decision variables are also described.

  20. Play-level distributions of estimates of recovery factors for a miscible carbon dioxide enhanced oil recovery method used in oil reservoirs in the conterminous United States (United States)

    Attanasi, E.D.; Freeman, P.A.


    In a U.S. Geological Survey (USGS) study, recovery-factor estimates were calculated by using a publicly available reservoir simulator (CO2 Prophet) to estimate how much oil might be recovered with the application of a miscible carbon dioxide (CO2) enhanced oil recovery (EOR) method to technically screened oil reservoirs located in onshore and State offshore areas in the conterminous United States. A recovery factor represents the percentage of an oil reservoir’s original oil in place estimated to be recoverable by the application of a miscible CO2-EOR method. The USGS estimates were calculated for 2,018 clastic and 1,681 carbonate candidate reservoirs in the “Significant Oil and Gas Fields of the United States Database” prepared by Nehring Associates, Inc. (2012).

  1. Holocene sea level history, modern-day vertical uplift and forebulge evolution: further constraints on the GIA process over the North American continent (United States)

    Roy, K.


    The intense cycles of glaciation and deglaciation that have characterized Earth's climate over the past 900,000 years have had a profound impact on the Earth system. The significant imprints that the related variations in surface mass load have had on sea level history and the Earth's shape can be employed to constrain models of the glacial isostatic adjustment (GIA) process. These models rely on two fundamental inputs, namely a history of ice-sheet loading and a representation of the variation of viscosity in the lithosphere and in the mantle. Especially important GIA related observables include Global Positioning System (GPS) observations of the movement of the solid Earth's surface and inferences of past relative sea level evolution. Depending on the region from which they originate, these data provide information on different model characteristics. In particular, while the relative sea level constrained relaxation occurring near former centers of glaciation can be relatively easily parametrized to facilitate an inversion for mantle viscosity, the same process in the regions of forebulge collapse is much more complex but nevertheless provides essential further constraints upon mantle viscosity. In this paper, we examine how recently available high-quality datasets of relative sea level evolution from the U.S. East coast (Engelhart et al., Geology, 2011) and the North American Pacific coast (Engelhart et al., QSR, 2015) can be employed, together with an extensive dataset of space-geodetic observations of present-day vertical uplift of the crust over North America (Peltier et al., JGR - Solid Earth, 2015), to further improve the latest state-of-the-art ICE-6G_C (VM5a) model (Peltier et al., JGR - Solid Earth, 2015). It will be demonstrated that the high quality of the data does not only provide further constraints on radial variations of viscosity in the mantle, but also on the history of the deglaciation that occurred over North America after the Last Glacial

  2. Multiobjective reservoir operating rules based on cascade reservoir input variable selection method (United States)

    Yang, Guang; Guo, Shenglian; Liu, Pan; Li, Liping; Xu, Chongyu


    The input variable selection in multiobjective cascade reservoir operation is an important and difficult task. To address this problem, this study proposes the cascade reservoir input variable selection (CIS) method that searches for the most valuable input variables for decision making in multiple-objectivity cascade reservoir operations. From a case study of Hanjiang cascade reservoirs in China, we derive reservoir operating rules based on the combination of CIS and Gaussian radial basis functions (RBFs) methods and optimize the rules through Pareto-archived dynamically dimensioned search (PA-DDS) with two objectives: to maximize both power generation and water supply. We select the most effective input variables and evaluate their impacts on cascade reservoir operations. From the simulated trajectories of reservoir water level, power generation, and water supply, we analyze the multiobjective operating rules with several input variables. The results demonstrate that the CIS method performs well in the selection of input variables for the cascade reservoir operation, and the RBFs method can fully express the nonlinear operating rules for cascade reservoirs. We conclude that the CIS method is an effective and stable approach to identifying the most valuable information from a large number of candidate input variables. While the reservoir storage state is the most valuable information for the Hanjiang cascade reservoir multiobjective operation, the reservoir inflow is the most effective input variable for the single-objective operation of Danjiangkou.

  3. Risk Decision Making Model for Reservoir Floodwater resources Utilization (United States)

    Huang, X.


    Floodwater resources utilization(FRU) can alleviate the shortage of water resources, but there are risks. In order to safely and efficiently utilize the floodwater resources, it is necessary to study the risk of reservoir FRU. In this paper, the risk rate of exceeding the design flood water level and the risk rate of exceeding safety discharge are estimated. Based on the principle of the minimum risk and the maximum benefit of FRU, a multi-objective risk decision making model for FRU is constructed. Probability theory and mathematical statistics method is selected to calculate the risk rate; C-D production function method and emergy analysis method is selected to calculate the risk benefit; the risk loss is related to flood inundation area and unit area loss; the multi-objective decision making problem of the model is solved by the constraint method. Taking the Shilianghe reservoir in Jiangsu Province as an example, the optimal equilibrium solution of FRU of the Shilianghe reservoir is found by using the risk decision making model, and the validity and applicability of the model are verified.

  4. Prediction of long-term influence of ONKALO and Korvensuo reservoir on groundwater level and water balance components on Olkiluoto island

    International Nuclear Information System (INIS)

    Karvonen, T.


    The Olkiluoto surface hydrological model was used to compute the influence of various ONKALO leakage scenarios on changes in groundwater level in overburden soils and hydraulic heads in the bedrock. Moreover, the model effect of ONKALO leakages on water balance components of the Olkiluoto Island (runoff, evapotranspiration, discharge to the sea area through the bedrock and discharge from the Korvensuo reservoir) and on the thickness and area of unsaturated bedrock layer were computed. Leakages into ONKALO lower the groundwater level in overburden soils especially during those years when precipitation is smaller than the long-term average value 550 mm a -1 . According to model results groundwater level can be below sea level if leakage rate into ONKALO is 180 l/min or more. If leakage rate is smaller than 180 l/min groundwater level is above sea level all the time also during dry years. The modelling results show that there are local water divides inside the island both on the southern and northern side of ONKALO at all time points and for all leakage rates. The local water divides ensure that sea water cannot intrude to ONKALO via surface waters. A more detailed version of the Olkiluoto surface hydrological model was developed for the area around the infiltration experiment. Site scale data were available for the location of the most transmissive hydrogeological zones. The analysis of hydraulic responses has shown that there are local connections between different areas around the pumping drillhole OL-KR14. The importance of the local responses was verified by an additional small hydrogeological zone HZInf connecting HZ19A, HZ19C, OL-KR14, OL-PP66, OL-PP68 and OL-PP69 that was added to the model. In future studies it is necessary to describe the local zones explicitly in the model to allow more realistic flow simulations. Discharge has been measured manually in four measuring weirs since March 2003. The old V-shaped measuring weirs were replaced by new automatic

  5. Constrained genetic algorithms for optimizing multi-use reservoir operation (United States)

    Chang, Li-Chiu; Chang, Fi-John; Wang, Kuo-Wei; Dai, Shin-Yi


    To derive an optimal strategy for reservoir operations to assist the decision-making process, we propose a methodology that incorporates the constrained genetic algorithm (CGA) where the ecological base flow requirements are considered as constraints to water release of reservoir operation when optimizing the 10-day reservoir storage. Furthermore, a number of penalty functions designed for different types of constraints are integrated into reservoir operational objectives to form the fitness function. To validate the applicability of this proposed methodology for reservoir operations, the Shih-Men Reservoir and its downstream water demands are used as a case study. By implementing the proposed CGA in optimizing the operational performance of the Shih-Men Reservoir for the last 20 years, we find this method provides much better performance in terms of a small generalized shortage index (GSI) for human water demands and greater ecological base flows for most of the years than historical operations do. We demonstrate the CGA approach can significantly improve the efficiency and effectiveness of water supply capability to both human and ecological base flow requirements and thus optimize reservoir operations for multiple water users. The CGA can be a powerful tool in searching for the optimal strategy for multi-use reservoir operations in water resources management.

  6. Optimal Reoperation of Multi-Reservoirs for Integrated Watershed Management with Multiple Benefits

    Directory of Open Access Journals (Sweden)

    Xinyi Xu


    Full Text Available Constructing reservoirs can make more efficient use of water resources for human society. However, the negative impacts of these projects on the environment are often ignored. Optimal reoperation of reservoirs, which considers not only in socio-economic values but also environmental benefits, is increasingly important. A model of optimal reoperation of multi-reservoirs for integrated watershed management with multiple benefits was proposed to alleviate the conflict between water use and environmental deterioration. The social, economic, water quality and ecological benefits were respectively taken into account as the scheduling objectives and quantified according to economic models. River minimum ecological flows and reservoir water levels based on flood control were taken as key constraint conditions. Feasible search discrete differential dynamic programming (FS-DDDP was used to run the model. The proposed model was used in the upstream of the Nanpan River, to quantitatively evaluate the difference between optimal reoperation and routine operation. The results indicated that the reoperation could significantly increase the water quality benefit and have a minor effect on the benefits of power generation and irrigation under different hydrological years. The model can be readily adapted to other multi-reservoir systems for water resources management.

  7. Data Compression of Hydrocarbon Reservoir Simulation Grids

    KAUST Repository

    Chavez, Gustavo Ivan


    A dense volumetric grid coming from an oil/gas reservoir simulation output is translated into a compact representation that supports desired features such as interactive visualization, geometric continuity, color mapping and quad representation. A set of four control curves per layer results from processing the grid data, and a complete set of these 3-dimensional surfaces represents the complete volume data and can map reservoir properties of interest to analysts. The processing results yield a representation of reservoir simulation results which has reduced data storage requirements and permits quick performance interaction between reservoir analysts and the simulation data. The degree of reservoir grid compression can be selected according to the quality required, by adjusting for different thresholds, such as approximation error and level of detail. The processions results are of potential benefit in applications such as interactive rendering, data compression, and in-situ visualization of large-scale oil/gas reservoir simulations.

  8. Reservoir fisheries of Asia

    International Nuclear Information System (INIS)

    Silva, S.S. De.


    At a workshop on reservoir fisheries research, papers were presented on the limnology of reservoirs, the changes that follow impoundment, fisheries management and modelling, and fish culture techniques. Separate abstracts have been prepared for three papers from this workshop

  9. [Fractions and adsorption characteristics of phosphorus on sediments and soils in water level fluctuating zone of the Pengxi River, a tributary of the Three Gorges Reservoir]. (United States)

    Sun, Wen-Bin; Du, Bin; Zhao, Xiu-Lan; He, Bing-Hui


    The sediment, one of the key factors leading to the eutrophication of water bodies, is an important ecological component of natural water body. In order to investigate the morphological characteristics and moving-transiting rule of phosphorus in the sediments of the Pengxi River, a tributary of the Three Gorges Reservoir, the distributions of different phosphorus forms on the three cross-section in the sediments and three soil types of riparian zone were investigated using the sequential extraction method. The characteristics of phosphorus adsorption on the sediments were also investigated by batch experiments. The equilibrium phosphorus concentrations at zero adsorption (EPC0) on those sediments were estimated using the Henry linear models. The results show that the total phosphorus (TP) contents of these sediments and soils of riparian zone were 0.80-1.45 g x kg(-1) and 0.65-1.16 g x kg(-1), respectively. Phosphorus in sediments and soils were divided into inorganic phosphorus (IP) and organic phosphorus (Or-P), and the inorganic phosphorus was the dominant component of TP. Of the inorganic phosphorus fractions, the percentages of phosphorus bounded to calcium (Ca-P) and occluded phosphorus (O-P) from sediments were higher than 80%, implying that the contents of phosphorus were mainly influenced by their bedrocks and the sedimentary environmental conditions, not by the activities of human beings. The fractions of Ca-P and O-P were the dominant components of inorganic phosphorus in alluvial soil and purple soil, while the fraction of O-P was the highest in the paddy soil. The EPC0 values of the sediments from the sections of Huangshi, Shuangjiang and Gaoyang were 0.08, 0.13 and 0.11 mg x L(-1) respectively, but the EPC0 values of the alluvial soil, purple soil and paddy soil located in riparian zone were 0.08, 0.09 and 0.04 mg x L(-1), respectively. Correlation analysis shows that the values of EPC0 positively related to the contents of total phosphorus and clay

  10. Large reservoirs: Chapter 17 (United States)

    Miranda, Leandro E.; Bettoli, Phillip William


    Large impoundments, defined as those with surface area of 200 ha or greater, are relatively new aquatic ecosystems in the global landscape. They represent important economic and environmental resources that provide benefits such as flood control, hydropower generation, navigation, water supply, commercial and recreational fisheries, and various other recreational and esthetic values. Construction of large impoundments was initially driven by economic needs, and ecological consequences received little consideration. However, in recent decades environmental issues have come to the forefront. In the closing decades of the 20th century societal values began to shift, especially in the developed world. Society is no longer willing to accept environmental damage as an inevitable consequence of human development, and it is now recognized that continued environmental degradation is unsustainable. Consequently, construction of large reservoirs has virtually stopped in North America. Nevertheless, in other parts of the world construction of large reservoirs continues. The emergence of systematic reservoir management in the early 20th century was guided by concepts developed for natural lakes (Miranda 1996). However, we now recognize that reservoirs are different and that reservoirs are not independent aquatic systems inasmuch as they are connected to upstream rivers and streams, the downstream river, other reservoirs in the basin, and the watershed. Reservoir systems exhibit longitudinal patterns both within and among reservoirs. Reservoirs are typically arranged sequentially as elements of an interacting network, filter water collected throughout their watersheds, and form a mosaic of predictable patterns. Traditional approaches to fisheries management such as stocking, regulating harvest, and in-lake habitat management do not always produce desired effects in reservoirs. As a result, managers may expend resources with little benefit to either fish or fishing. Some locally

  11. Stream, Lake, and Reservoir Management. (United States)

    Dai, Jingjing; Mei, Ying; Chang, Chein-Chi


    This review on stream, lake, and reservoir management covers selected 2016 publications on the focus of the following sections: Stream, lake, and reservoir management • Water quality of stream, lake, and reservoirReservoir operations • Models of stream, lake, and reservoir • Remediation and restoration of stream, lake, and reservoir • Biota of stream, lake, and reservoir • Climate effect of stream, lake, and reservoir.

  12. Status of Wheeler Reservoir

    Energy Technology Data Exchange (ETDEWEB)


    This is one in a series of status reports prepared by the Tennessee Valley Authority (TVA) for those interested in the conditions of TVA reservoirs. This overview of Wheeler Reservoir summarizes reservoir purposes and operation, reservoir and watershed characteristics, reservoir uses and use impairments, and water quality and aquatic biological conditions. The information presented here is from the most recent reports, publications, and original data available. If no recent data were available, historical data were summarized. If data were completely lacking, environmental professionals with special knowledge of the resource were interviewed. 12 refs., 2 figs.

  13. Cloud computing and Reservoir project

    International Nuclear Information System (INIS)

    Beco, S.; Maraschini, A.; Pacini, F.; Biran, O.


    The support for complex services delivery is becoming a key point in current internet technology. Current trends in internet applications are characterized by on demand delivery of ever growing amounts of content. The future internet of services will have to deliver content intensive applications to users with quality of service and security guarantees. This paper describes the Reservoir project and the challenge of a reliable and effective delivery of services as utilities in a commercial scenario. It starts by analyzing the needs of a future infrastructure provider and introducing the key concept of a service oriented architecture that combines virtualisation-aware grid with grid-aware virtualisation, while being driven by business service management. This article will then focus on the benefits and the innovations derived from the Reservoir approach. Eventually, a high level view of Reservoir general architecture is illustrated.

  14. Development of gas and gas condensate reservoirs

    Energy Technology Data Exchange (ETDEWEB)



    In the study of gas reservoir development, the first year topics are restricted on reservoir characterization. There are two types of reservoir characterization. One is the reservoir formation characterization and the other is the reservoir fluid characterization. For the reservoir formation characterization, calculation of conditional simulation was compared with that of unconditional simulation. The results of conditional simulation has higher confidence level than the unconditional simulation because conditional simulation considers the sample location as well as distance correlation. In the reservoir fluid characterization, phase behavior calculations revealed that the component grouping is more important than the increase of number of components. From the liquid volume fraction with pressure drop, the phase behavior of reservoir fluid can be estimated. The calculation results of fluid recombination, constant composition expansion, and constant volume depletion are matched very well with the experimental data. In swelling test of the reservoir fluid with lean gas, the accuracy of dew point pressure forecast depends on the component characterization. (author). 28 figs., 10 tabs.

  15. System-Level Operational and Adequacy Impact Assessment of Photovoltaic and Distributed Energy Storage, with Consideration of Inertial Constraints, Dynamic Reserve and Interconnection Flexibility

    Directory of Open Access Journals (Sweden)

    Lingxi Zhang


    Full Text Available The growing penetration of solar photovoltaic (PV systems requires a fundamental understanding of its impact at a system-level. Furthermore, distributed energy storage (DES technologies, such as batteries, are attracting great interest owing to their ability to provide support to systems with large-scale renewable generation, such as PV. In this light, the system-level impacts of PV and DES are assessed from both operational and adequacy perspectives. Different control strategies for DES are proposed, namely: (1 centralised, to support system operation in the presence of increasing requirements on system ramping and frequency control; and (2 decentralised, to maximise the harnessing of solar energy from individual households while storing electricity generated by PV panels to provide system capacity on request. The operational impacts are assessed by deploying a multi-service unit commitment model with consideration of inertial constraints, dynamic reserve allocation, and interconnection flexibility, while the impacts on adequacy of supply are analysed by assessing the capacity credit of PV and DES through different metrics. The models developed are then applied to different future scenarios for the Great Britain power system, whereby an electricity demand increase due to electrification is also considered. The numerical results highlight the importance of interconnectors to provide flexibility. On the other hand, provision of reserves, as opposed to energy arbitrage, from DES that are integrated into system operation is seen as the most effective contribution to improve system performance, which in turn also decreases the role of interconnectors. DES can also contribute to providing system capacity, but to an extent that is limited by their individual and aggregated energy availability under different control strategies.

  16. Reservoir-induced seismicity at Castanhao reservoir, NE Brazil (United States)

    Nunes, B.; do Nascimento, A.; Ferreira, J.; Bezerra, F.


    Our case study - the Castanhão reservoir - is located in NE Brazil on crystalline rock at the Borborema Province. The Borborema Province is a major Proterozoic-Archean terrain formed as a consequence of convergence and collision of the São Luis-West Africa craton and the São Francisco-Congo-Kasai cratons. This reservoir is a 60 m high earth-filled dam, which can store up to 4.5 billion m3 of water. The construction begun in 1990 and finished in October 2003.The first identified reservoir-induced events occurred in 2003, when the water level was still low. The water reached the spillway for the first time in January 2004 and, after that, an increase in seismicity occured. The present study shows the results of a campaign done in the period from November 19th, 2009 to December 31th, 2010 at the Castanhão reservoir. We deployed six three-component digital seismographic station network around one of the areas of the reservoir. We analyzed a total of 77 events which were recorded in at least four stations. To determine hypocenters and time origin, we used HYPO71 program (Lee & Lahr, 1975) assuming a half-space model with following parameters: VP= 5.95 km/s and VP/VS=1.73. We also performed a relocation of these events using HYPODD (Waldhauser & Ellsworth, 2000) programme. The input data used we used were catalogue data, with all absolute times. The results from the spatio-temporal suggest that different clusters at different areas and depths are triggered at different times due to a mixture of: i - pore pressure increase due to diffusion and ii - increase of pore pressure due to the reservoir load.

  17. On Constraints in Assembly Planning

    Energy Technology Data Exchange (ETDEWEB)

    Calton, T.L.; Jones, R.E.; Wilson, R.H.


    Constraints on assembly plans vary depending on product, assembly facility, assembly volume, and many other factors. Assembly costs and other measures to optimize vary just as widely. To be effective, computer-aided assembly planning systems must allow users to express the plan selection criteria that appIy to their products and production environments. We begin this article by surveying the types of user criteria, both constraints and quality measures, that have been accepted by assembly planning systems to date. The survey is organized along several dimensions, including strategic vs. tactical criteria; manufacturing requirements VS. requirements of the automated planning process itself and the information needed to assess compliance with each criterion. The latter strongly influences the efficiency of planning. We then focus on constraints. We describe a framework to support a wide variety of user constraints for intuitive and efficient assembly planning. Our framework expresses all constraints on a sequencing level, specifying orders and conditions on part mating operations in a number of ways. Constraints are implemented as simple procedures that either accept or reject assembly operations proposed by the planner. For efficiency, some constraints are supplemented with special-purpose modifications to the planner's algorithms. Fast replanning enables an interactive plan-view-constrain-replan cycle that aids in constraint discovery and documentation. We describe an implementation of the framework in a computer-aided assembly planning system and experiments applying the system to a number of complex assemblies, including one with 472 parts.

  18. Ant colony optimization and constraint programming

    CERN Document Server

    Solnon, Christine


    Ant colony optimization is a metaheuristic which has been successfully applied to a wide range of combinatorial optimization problems. The author describes this metaheuristic and studies its efficiency for solving some hard combinatorial problems, with a specific focus on constraint programming. The text is organized into three parts. The first part introduces constraint programming, which provides high level features to declaratively model problems by means of constraints. It describes the main existing approaches for solving constraint satisfaction problems, including complete tree search

  19. Improving reservoir history matching of EM heated heavy oil reservoirs via cross-well seismic tomography

    KAUST Repository

    Katterbauer, Klemens


    Enhanced recovery methods have become significant in the industry\\'s drive to increase recovery rates from oil and gas reservoirs. For heavy oil reservoirs, the immobility of the oil at reservoir temperatures, caused by its high viscosity, limits the recovery rates and strains the economic viability of these fields. While thermal recovery methods, such as steam injection or THAI, have extensively been applied in the field, their success has so far been limited due to prohibitive heat losses and the difficulty in controlling the combustion process. Electromagnetic (EM) heating via high-frequency EM radiation has attracted attention due to its wide applicability in different environments, its efficiency, and the improved controllability of the heating process. While becoming a promising technology for heavy oil recovery, its effect on overall reservoir production and fluid displacements are poorly understood. Reservoir history matching has become a vital tool for the oil & gas industry to increase recovery rates. Limited research has been undertaken so far to capture the nonlinear reservoir dynamics and significantly varying flow rates for thermally heated heavy oil reservoir that may notably change production rates and render conventional history matching frameworks more challenging. We present a new history matching framework for EM heated heavy oil reservoirs incorporating cross-well seismic imaging. Interfacing an EM heating solver to a reservoir simulator via Andrade’s equation, we couple the system to an ensemble Kalman filter based history matching framework incorporating a cross-well seismic survey module. With increasing power levels and heating applied to the heavy oil reservoirs, reservoir dynamics change considerably and may lead to widely differing production forecasts and increased uncertainty. We have shown that the incorporation of seismic observations into the EnKF framework can significantly enhance reservoir simulations, decrease forecasting

  20. Economics of Developing Hot Stratigraphic Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Greg Mines; Hillary Hanson; Rick Allis; Joseph Moore


    Stratigraphic geothermal reservoirs at 3 – 4 km depth in high heat-flow basins are capable of sustaining 100 MW-scale power plants at about 10 c/kWh. This paper examines the impacts on the levelized cost of electricity (LCOE) of reservoir depth and temperature, reservoir productivity, and drillhole/casing options. For a reservoir at 3 km depth with a moderate productivity index by hydrothermal reservoir standards (about 50 L/s/MPa, 5.6 gpm/psi), an LCOE of 10c/kWh requires the reservoir to be at about 200°C. This is the upper temperature limit for pumps. The calculations assume standard hydrothermal drilling costs, with the production interval completed with a 7 inch liner in an 8.5 inch hole. If a reservoir at 4 km depth has excellent permeability characteristics with a productivity index of 100 L/s/MPa (11.3 gpm/psi), then the LCOE is about 11 c/kWh assuming the temperature decline rate with development is not excessive (< 1%/y, with first thermal breakthrough delayed by about 10 years). Completing wells with modest horizontal legs (e.g. several hundred meters) may be important for improving well productivity because of the naturally high, sub-horizontal permeability in this type of reservoir. Reducing the injector/producer well ratio may also be cost-effective if the injectors are drilled as larger holes.

  1. The Alphabet Soup of HIV Reservoir Markers. (United States)

    Sharaf, Radwa R; Li, Jonathan Z


    Despite the success of antiretroviral therapy in suppressing HIV, life-long therapy is required to avoid HIV reactivation from long-lived viral reservoirs. Currently, there is intense interest in searching for therapeutic interventions that can purge the viral reservoir to achieve complete remission in HIV patients off antiretroviral therapy. The evaluation of such interventions relies on our ability to accurately and precisely measure the true size of the viral reservoir. In this review, we assess the most commonly used HIV reservoir assays, as a clear understanding of the strengths and weaknesses of each is vital for the accurate interpretation of results and for the development of improved assays. The quantification of intracellular or plasma HIV RNA or DNA levels remains the most commonly used tests for the characterization of the viral reservoir. While cost-effective and high-throughput, these assays are not able to differentiate between replication-competent or defective fractions or quantify the number of infected cells. Viral outgrowth assays provide a lower bound for the fraction of cells that can produce infectious virus, but these assays are laborious, expensive and substantially underestimate the potential reservoir of replication-competent provirus. Newer assays are now available that seek to overcome some of these problems, including full-length proviral sequencing, inducible HIV RNA assays, ultrasensitive p24 assays and murine adoptive transfer techniques. The development and evaluation of strategies for HIV remission rely upon our ability to accurately and precisely quantify the size of the remaining viral reservoir. At this time, all current HIV reservoir assays have drawbacks such that combinations of assays are generally needed to gain a more comprehensive view of the viral reservoir. The development of novel, rapid, high-throughput assays that can sensitively quantify the levels of the replication-competent HIV reservoir is still needed.


    Constantz, Jim; Murphy, Fred


    The mariotte reservoir supplies water at a constant hydraulic pressure by self-regulation of its internal gas pressure. Automated outflow measurements from mariotte reservoirs are generally difficult because of the reservoir's self-regulation mechanism. This paper describes an automated flow meter specifically designed for use with mariotte reservoirs. The flow meter monitors changes in the mariotte reservoir's gas pressure during outflow to determine changes in the reservoir's water level. The flow measurement is performed by attaching a pressure transducer to the top of a mariotte reservoir and monitoring gas pressure changes during outflow with a programmable data logger. The advantages of the new automated flow measurement techniques include: (i) the ability to rapidly record a large range of fluxes without restricting outflow, and (ii) the ability to accurately average the pulsing flow, which commonly occurs during outflow from the mariotte reservoir.

  3. [Demographic constraints]. (United States)

    Cartier, M; Veron, J


    This is a comparative analysis of China and India's policies and programs designed to reduce the rate of population growth. The authors note that these two countries also differ with regard to the emphasis given to primary, secondary, or higher education and to levels of female labor force participation. They conclude that over the next 10 years both will face a growing population, an excess of manpower over available jobs, and regional disparities in development that could threaten internal stability.

  4. Transport of reservoir fines

    DEFF Research Database (Denmark)

    Yuan, Hao; Shapiro, Alexander; Stenby, Erling Halfdan

    Modeling transport of reservoir fines is of great importance for evaluating the damage of production wells and infectivity decline. The conventional methodology accounts for neither the formation heterogeneity around the wells nor the reservoir fines’ heterogeneity. We have developed an integral...


    African Journals Online (AJOL)

    Calls have been made to the government through various media to assist its populace in combating this nagging problem. It was concluded that sediment maximum accumulation is experienced in reservoir during the periods of maximum flow. Keywords: reservoir model, siltation, sediment, catchment, sediment transport. 1.

  6. Dynamic reservoir well interaction

    NARCIS (Netherlands)

    Sturm, W.L.; Belfroid, S.P.C.; Wolfswinkel, O. van; Peters, M.C.A.M.; Verhelst, F.J.P.C.M.


    In order to develop smart well control systems for unstable oil wells, realistic modeling of the dynamics of the well is essential. Most dynamic well models use a semi-steady state inflow model to describe the inflow of oil and gas from the reservoir. On the other hand, reservoir models use steady

  7. Reservoir Engineering Management Program

    Energy Technology Data Exchange (ETDEWEB)

    Howard, J.H.; Schwarz, W.J.


    The Reservoir Engineering Management Program being conducted at Lawrence Berkeley Laboratory includes two major tasks: 1) the continuation of support to geothermal reservoir engineering related work, started under the NSF-RANN program and transferred to ERDA at the time of its formation; 2) the development and subsequent implementation of a broad plan for support of research in topics related to the exploitation of geothermal reservoirs. This plan is now known as the GREMP plan. Both the NSF-RANN legacies and GREMP are in direct support of the DOE/DGE mission in general and the goals of the Resource and Technology/Resource Exploitation and Assessment Branch in particular. These goals are to determine the magnitude and distribution of geothermal resources and reduce risk in their exploitation through improved understanding of generically different reservoir types. These goals are to be accomplished by: 1) the creation of a large data base about geothermal reservoirs, 2) improved tools and methods for gathering data on geothermal reservoirs, and 3) modeling of reservoirs and utilization options. The NSF legacies are more research and training oriented, and the GREMP is geared primarily to the practical development of the geothermal reservoirs. 2 tabs., 3 figs.

  8. Assessment of the economic impact of environmental constraints on annual hydropower plant operation

    International Nuclear Information System (INIS)

    Guisández, Ignacio; Pérez-Díaz, Juan I.; Wilhelmi, José R.


    Environmental constraints imposed on hydropower operation are becoming increasingly restrictive. These constraints may reduce the operational flexibility of a hydro plant and therefore its revenue. The objective of this paper is to assess the economic impact of minimum environmental flows and maximum ramping rates on the annual operation of a hydropower plant. For this purpose, a revenue-driven annual optimization model based on discrete dynamic programming and mixed integer linear programming is used. The model considers hourly water inflows and energy prices, limits on reservoir level and water discharge, power generation dependence on the available head, wear and tear costs of hydro units caused by power variations, start-up and shut-down costs of hydro units, and the above-mentioned environmental constraints. In order to show the applicability of the proposed methodology, it is used in a real hydropower plant under five different water year types and 56 distinct combinations of the considered environmental constraints. The results indicate that the revenues of the hydropower plant are very sensitive to the presence and magnitudes of these constraints. Annual losses increase quadratically as a function of the maximum ramping rates and almost linearly as a function of the minimum environmental flows. - Highlights: • The effect of environmental constraints on the annual income of a hydro plant has been assessed. • A revenue-driven optimization model has been used for this purpose. • The model is based on discrete dynamic programming and mixed integer linear programming. • Different water year types and magnitudes of the environmental constraints have been studied. • Results show that annual income is very sensitive to the presence and magnitude of these constraints

  9. Destratification of an impounding reservoir using compressed air??case of Mudi reservoir, Blantyre, Malawi (United States)

    Chipofya, V. H.; Matapa, E. J.

    This paper reviews the operational and cost effectiveness of a compressed air destratification system that was installed in the Mudi reservoir for destratifying the reservoir. Mudi reservoir is a raw water source for the Blantyre Water Board. It has a capacity of 1,400,000 cubic metres. The reservoir is 15.3 m deep at top water level. In the absence of any artificial circulation of air, the reservoir stratifies into two layers. There is a warm epilimnion in the top 3 m of the reservoir, with temperatures ranging from 23 to 26 °C. There is prolific algal growth in this layer. The bottom layer has much lower temperatures, and is oxygen deficient. Under such anaerobic conditions, ammonia, sulphides, iron and manganese are released from the sediments of the reservoir. As a result of nutrient inflow from the catchments, coupled with tropical ambient temperatures, the reservoir is most times infested with blue-green algae. This results into water treatment problems in respect of taste and odour and iron and manganese soluble salts. To abate such problems, air is artificially circulated in the reservoir, near the intake tower, through a perforated pipe that is connected to an electrically driven compressor. This causes artificial circulation of water in the hypolimnion region of the reservoir. As a result of this circulation, a hostile environment that inhibits the propagation of algae is created. Dissolved oxygen and temperature profiles are practically uniform from top to bottom of reservoir. Concentrations of iron and manganese soluble salts are much reduced at any of the draw-off points available for the water treatment process. The paper concludes by highlighting the significant cost savings in water treatment that are accrued from the use of compressed air destratification in impounding water storage reservoirs for the control of algae and other chemical pollutants.

  10. A reservoir operating method for riverine ecosystem protection, reservoir sedimentation control and water supply (United States)

    Yin, Xin-An; Yang, Zhi-Feng; Petts, Geoffrey E.; Kondolf, G. Mathias


    Riverine ecosystem protection requires the maintenance of natural flow and sediment regimes downstream from dams. In reservoir management schedules this requirement should be integrated with sedimentation control and human water supply. However, traditional eco-friendly reservoir operating methods have usually only considered the natural flow regime. This paper seeks to develop a reservoir operating method that accounts for both the natural flow and sediment regimes as well as optimizing the water supply allocations. Herein, reservoir water level (RWL), sediment-occupied ratio of reservoir volume (SOR) and rate of change of SOR (RCSOR) are adopted as three triggers of a drawdown-flushing-based sediment management policy. Two different groups of reservoir operating rule curves (RORCs) are designed for sediment-flushing and non-sediment-flushing years, and the three triggers, RWL, SOR and RCSOR, are used to change the “static” RORCs to “dynamic” ones. The approach is applied to the Wangkuai Reservoir, China to test its effectiveness. This shows that the approach can improve the flexibility of reservoir operators to balance the reservoir management, water supply management and the flow and sediment needs of the downstream riverine ecosystem.

  11. Stochastic reservoir operation under drought with fuzzy objectives

    International Nuclear Information System (INIS)

    Parent, E.; Duckstein, L.


    Biojective reservoir operation under drought conditions is investigated using stochastic dynamic programming. As both objectives (irrigation water supply, water quality) can only be defined imprecisely, a fuzzy set approach is used to encode the decision maker (DM)'s preferences. The nature driven components are modeled by means of classical stage-state system analysis. The state is three dimensional (inflow memory, drought irrigation index, reservoir level); the decision vector elements are release and irrigation allocation. Stochasticity stems from the random nature of inflows and irrigation demands. The transition function includes a lag one inflow Markov model and mass balance equations. The human driven component is designed as a confluence of fuzzy objectives and constraints after Bellman and Zadeh. Fuzzy numbers are assessed to represent the DM's objectives by two different techniques, the direct one and indirect pairwise comparison. The real case study of the Neste river system in southwestern France is used to illustrate the approach; the result are compared to a classical sequential decision theoretical model derived earlier from the viewpoints of ease of modeling, computational efforts, plausibility and robustness of results

  12. First assessment of the ecological status of Karaoun reservoir, Lebanon

    International Nuclear Information System (INIS)

    Fadel, A.; Lemaire, B.; Vinc on Leite, B.; Tassin, B.; Amacha, N.; Slim, K.; Atoui, A.


    Many reservoirs have been constructed throughout the world during the 20th century, with many also suffering from eutrophication. The resulting increased phytoplankton biomass in reservoirs impairs their use. Except for Lake Kinneret, the environmental status of lakes and reservoirs in the Middle East is poorly documented. Karaoun reservoir, also known as Qaroun, Qaraoun or Qarun, is the largest water body in Lebanon, having been constructed for irrigation and hydropower production. This present study reviews Karaoun reservoir, including its characteristics, uses, water quality and phytoplankton succession, to assess the environmental status of the reservoir on the basis of the few existing previous publications about the reservoir. Since 2004, which is 39 years after its construction, the reservoir is considered to be hypereutrophic, with low phytoplankton biodiversity and regular blooms of toxic cyanobacteria. The nutrient and trace metal concentrations would not prevent use of the reservoir for a drinking water supply for Beirut, as is currently being planned, although not all the micropollutants in the lake were documented. Karaoun reservoir is compared to other monitored lakes and reservoirs around the Mediterranean Sea. They share annual toxic cyanobacteria blooms of Aphanizomenon ovalisporum and of Microcystis aeruginosa. The phytoplankton composition and succession of Karaoun reservoir is more similar to El Gergal reservoir (Spain) than nearby natural lakes such as Lake Kinneret (Israel) and Lake Trichonis (Greece). Phytoplankton diversity in Karaoun reservoir was the lowest, due to higher nutrient concentrations and a larger decrease in water level in the dry season. Karaoun reservoir represents an interesting example of the potential response of the phytoplankton community in other lakes and reservoirs during the drought periods expected to occur as a result of global climate change. (author)

  13. Gas coning control for smart wells using a dynamic coupled well-reservoir simulator

    NARCIS (Netherlands)

    Leemhuis, A.P.; Nennie, E.D.; Belfroid, S.P.C.; Alberts, G.J.N.; Peters, E.; Joosten, G.J.P.


    A strong increase in gas inflow due to gas coning and the resulting bean-back because of Gas to Oil Ratio (GOR) constraints can severely limit oil production and reservoir drive energy. In this paper we will use a coupled reservoir-well model to demonstrate that oil production can be increased by

  14. Sediment management for reservoir

    International Nuclear Information System (INIS)

    Rahman, A.


    All natural lakes and reservoirs whether on rivers, tributaries or off channel storages are doomed to be sited up. Pakistan has two major reservoirs of Tarbela and Managla and shallow lake created by Chashma Barrage. Tarbela and Mangla Lakes are losing their capacities ever since first impounding, Tarbela since 1974 and Mangla since 1967. Tarbela Reservoir receives average annual flow of about 62 MAF and sediment deposits of 0.11 MAF whereas Mangla gets about 23 MAF of average annual flows and is losing its storage at the rate of average 34,000 MAF annually. The loss of storage is a great concern and studies for Tarbela were carried out by TAMS and Wallingford to sustain its capacity whereas no study has been done for Mangla as yet except as part of study for Raised Mangla, which is only desk work. Delta of Tarbala reservoir has advanced to about 6.59 miles (Pivot Point) from power intakes. In case of liquefaction of delta by tremor as low as 0.12g peak ground acceleration the power tunnels I, 2 and 3 will be blocked. Minimum Pool of reservoir is being raised so as to check the advance of delta. Mangla delta will follow the trend of Tarbela. Tarbela has vast amount of data as reservoir is surveyed every year, whereas Mangla Reservoir survey was done at five-year interval, which has now been proposed .to be reduced to three-year interval. In addition suspended sediment sampling of inflow streams is being done by Surface Water Hydrology Project of WAPDA as also some bed load sampling. The problem of Chasma Reservoir has also been highlighted, as it is being indiscriminately being filled up and drawdown several times a year without regard to its reaction to this treatment. The Sediment Management of these reservoirs is essential and the paper discusses pros and cons of various alternatives. (author)

  15. Full Waveform Inversion for Reservoir Characterization - A Synthetic Study

    KAUST Repository

    Zabihi Naeini, E.


    Most current reservoir-characterization workflows are based on classic amplitude-variation-with-offset (AVO) inversion techniques. Although these methods have generally served us well over the years, here we examine full-waveform inversion (FWI) as an alternative tool for higher-resolution reservoir characterization. An important step in developing reservoir-oriented FWI is the implementation of facies-based rock physics constraints adapted from the classic methods. We show that such constraints can be incorporated into FWI by adding appropriately designed regularization terms to the objective function. The advantages of the proposed algorithm are demonstrated on both isotropic and VTI (transversely isotropic with a vertical symmetry axis) models with pronounced lateral and vertical heterogeneity. The inversion results are explained using the theoretical radiation patterns produced by perturbations in the medium parameters.

  16. Reservoir characterization of Pennsylvanian sandstone reservoirs. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kelkar, M.


    This final report summarizes the progress during the three years of a project on Reservoir Characterization of Pennsylvanian Sandstone Reservoirs. The report is divided into three sections: (i) reservoir description; (ii) scale-up procedures; (iii) outcrop investigation. The first section describes the methods by which a reservoir can be described in three dimensions. The next step in reservoir description is to scale up reservoir properties for flow simulation. The second section addresses the issue of scale-up of reservoir properties once the spatial descriptions of properties are created. The last section describes the investigation of an outcrop.

  17. Beyond the replication-competent HIV reservoir: transcription and translation-competent reservoirs. (United States)

    Baxter, Amy E; O'Doherty, Una; Kaufmann, Daniel E


    Recent years have seen a substantial increase in the number of tools available to monitor and study HIV reservoirs. Here, we discuss recent technological advances that enable an understanding of reservoir dynamics beyond classical assays to measure the frequency of cells containing provirus able to propagate a spreading infection (replication-competent reservoir). Specifically, we focus on the characterization of cellular reservoirs containing proviruses able to transcribe viral mRNAs (so called transcription-competent) and translate viral proteins (translation-competent). We suggest that the study of these alternative reservoirs provides complementary information to classical approaches, crucially at a single-cell level. This enables an in-depth characterization of the cellular reservoir, both following reactivation from latency and, importantly, directly ex vivo at baseline. Furthermore, we propose that the study of cellular reservoirs that may not contain fully replication-competent virus, but are able to produce HIV mRNAs and proteins, is of biological importance. Lastly, we detail some of the key contributions that the study of these transcription and translation-competent reservoirs has made thus far to investigations into HIV persistence, and outline where these approaches may take the field next.

  18. Optimizing withdrawal from drinking water reservoirs to reduce downstream temperature pollution and reservoir hypoxia. (United States)

    Weber, M; Rinke, K; Hipsey, M R; Boehrer, B


    Sustainable management of drinking water reservoirs requires balancing the demands of water supply whilst minimizing environmental impact. This study numerically simulates the effect of an improved withdrawal scheme designed to alleviate the temperature pollution downstream of a reservoir. The aim was to identify an optimal withdrawal strategy such that water of a desirable discharge temperature can be supplied downstream without leading to unacceptably low oxygen concentrations within the reservoir. First, we calibrated a one-dimensional numerical model for hydrodynamics and oxygen dynamics (GLM-AED2), verifying that the model reproduced water temperatures and hypolimnetic dissolved oxygen concentrations accurately over a 5 year period. Second, the model was extended to include an adaptive withdrawal functionality, allowing for a prescribed withdrawal temperature to be found, with the potential constraint of hypolimnetic oxygen concentration. Scenario simulations on epi-/metalimnetic withdrawal demonstrate that the model is able to autonomously determine the best withdrawal height depending on the thermal structure and the hypolimnetic oxygen concentration thereby optimizing the ability to supply a desirable discharge temperature to the downstream river during summer. This new withdrawal strategy also increased the hypolimnetic raw water volume to be used for drinking water supply, but reduced the dissolved oxygen concentrations in the deep and cold water layers (hypolimnion). Implications of the results for reservoir management are discussed and the numerical model is provided for operators as a simple and efficient tool for optimizing the withdrawal strategy within different reservoir contexts. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Controlling Eutrophication in A Mediterranean Shallow Reservoir by Phosphorus Loading Reduction: The Need for an Integrated Management Approach. (United States)

    Zaragüeta, Mikel; Acebes, Pablo


    Increased nutrient enrichment in Mediterranean standing waters has enhanced the risk of being affected by cyanobacterial blooms. Because phosphorus abatement is shaped as a crucial strategy for controlling eutrophication, this study introduces a structural thinking, experiential learning laboratory with animation dynamic model elaborated for Cazalegas Reservoir (Spain) to assess the feasibility of implementing a set of internal and external control measures and hydromorphological adjustments to meet the goal of oligotrophication. This shallow reservoir is another case where recurrent eutrophication has led to reach annual mean total phosphorus concentrations (0.16 ± 0.08 mg total phosphorus/L) over the threshold of current water policies, triggering cyanobacterial growth up to undesirable levels in summer time (approximately 50,000 cells/mL). Modeling results showed that (i) after upgrading water treatment in the main tributary, (ii) applying a lanthanum-modified bentonite into the water column and sediment, and (iii) increasing reservoir water level, in-lake P concentrations and cyanobacterial abundance decreased in an 88% (below 0.01 mg total phosphorus/L) and 84% (below 6000 cells/mL), respectively in the most critical periods. However, the constraints of the proposed management strategies are associated with their costs of implementation and the time span for a stable trophic recovery of the reservoir. In that end, integrated management approaches are aimed to be adopted by water managers to reach adequate ecological status of freshwater bodies.

  20. Controlling Eutrophication in A Mediterranean Shallow Reservoir by Phosphorus Loading Reduction: The Need for an Integrated Management Approach (United States)

    Zaragüeta, Mikel; Acebes, Pablo


    Increased nutrient enrichment in Mediterranean standing waters has enhanced the risk of being affected by cyanobacterial blooms. Because phosphorus abatement is shaped as a crucial strategy for controlling eutrophication, this study introduces a structural thinking, experiential learning laboratory with animation dynamic model elaborated for Cazalegas Reservoir (Spain) to assess the feasibility of implementing a set of internal and external control measures and hydromorphological adjustments to meet the goal of oligotrophication. This shallow reservoir is another case where recurrent eutrophication has led to reach annual mean total phosphorus concentrations (0.16 ± 0.08 mg total phosphorus/L) over the threshold of current water policies, triggering cyanobacterial growth up to undesirable levels in summer time (approximately 50,000 cells/mL). Modeling results showed that (i) after upgrading water treatment in the main tributary, (ii) applying a lanthanum-modified bentonite into the water column and sediment, and (iii) increasing reservoir water level, in-lake P concentrations and cyanobacterial abundance decreased in an 88% (below 0.01 mg total phosphorus/L) and 84% (below 6000 cells/mL), respectively in the most critical periods. However, the constraints of the proposed management strategies are associated with their costs of implementation and the time span for a stable trophic recovery of the reservoir. In that end, integrated management approaches are aimed to be adopted by water managers to reach adequate ecological status of freshwater bodies.

  1. A Study of the Optimal Planning Model for Reservoir Sustainable Management- A Case Study of Shihmen Reservoir (United States)

    Chen, Y. Y.; Ho, C. C.; Chang, L. C.


    The reservoir management in Taiwan faces lots of challenge. Massive sediment caused by landslide were flushed into reservoir, which will decrease capacity, rise the turbidity, and increase supply risk. Sediment usually accompanies nutrition that will cause eutrophication problem. Moreover, the unevenly distribution of rainfall cause water supply instability. Hence, how to ensure sustainable use of reservoirs has become an important task in reservoir management. The purpose of the study is developing an optimal planning model for reservoir sustainable management to find out an optimal operation rules of reservoir flood control and sediment sluicing. The model applies Genetic Algorithms to combine with the artificial neural network of hydraulic analysis and reservoir sediment movement. The main objective of operation rules in this study is to prevent reservoir outflow caused downstream overflow, minimum the gap between initial and last water level of reservoir, and maximum sluicing sediment efficiency. A case of Shihmen reservoir was used to explore the different between optimal operating rule and the current operation of the reservoir. The results indicate optimal operating rules tended to open desilting tunnel early and extend open duration during flood discharge period. The results also show the sluicing sediment efficiency of optimal operating rule is 36%, 44%, 54% during Typhoon Jangmi, Typhoon Fung-Wong, and Typhoon Sinlaku respectively. The results demonstrate the optimal operation rules do play a role in extending the service life of Shihmen reservoir and protecting the safety of downstream. The study introduces a low cost strategy, alteration of operation reservoir rules, into reservoir sustainable management instead of pump dredger in order to improve the problem of elimination of reservoir sediment and high cost.

  2. Composing constraint solvers

    NARCIS (Netherlands)

    P. Zoeteweij (Peter)


    htmlabstractComposing constraint solvers based on tree search and constraint propagation through generic iteration leads to efficient and flexible constraint solvers. This was demonstrated using OpenSolver, an abstract branch-and-propagate tree search engine that supports a wide range of relevant

  3. Modeling Reservoir-River Networks in Support of Optimizing Seasonal-Scale Reservoir Operations (United States)

    Villa, D. L.; Lowry, T. S.; Bier, A.; Barco, J.; Sun, A.


    HydroSCOPE (Hydropower Seasonal Concurrent Optimization of Power and the Environment) is a seasonal time-scale tool for scenario analysis and optimization of reservoir-river networks. Developed in MATLAB, HydroSCOPE is an object-oriented model that simulates basin-scale dynamics with an objective of optimizing reservoir operations to maximize revenue from power generation, reliability in the water supply, environmental performance, and flood control. HydroSCOPE is part of a larger toolset that is being developed through a Department of Energy multi-laboratory project. This project's goal is to provide conventional hydropower decision makers with better information to execute their day-ahead and seasonal operations and planning activities by integrating water balance and operational dynamics across a wide range of spatial and temporal scales. This presentation details the modeling approach and functionality of HydroSCOPE. HydroSCOPE consists of a river-reservoir network model and an optimization routine. The river-reservoir network model simulates the heat and water balance of river-reservoir networks for time-scales up to one year. The optimization routine software, DAKOTA (Design Analysis Kit for Optimization and Terascale Applications -, is seamlessly linked to the network model and is used to optimize daily volumetric releases from the reservoirs to best meet a set of user-defined constraints, such as maximizing revenue while minimizing environmental violations. The network model uses 1-D approximations for both the reservoirs and river reaches and is able to account for surface and sediment heat exchange as well as ice dynamics for both models. The reservoir model also accounts for inflow, density, and withdrawal zone mixing, and diffusive heat exchange. Routing for the river reaches is accomplished using a modified Muskingum-Cunge approach that automatically calculates the internal timestep and sub-reach lengths to match the conditions of

  4. Heavy oil reservoirs recoverable by thermal technology. Annual report

    Energy Technology Data Exchange (ETDEWEB)

    Kujawa, P.


    The purpose of this study was to compile data on reservoirs that contain heavy oil in the 8 to 25/sup 0/ API gravity range, contain at least ten million barrels of oil currently in place, and are non-carbonate in lithology. The reservoirs within these constraints were then analyzed in light of applicable recovery technology, either steam-drive or in situ combustion, and then ranked hierarchically as candidate reservoirs. The study is presented in three volumes. Volume I presents the project background and approach, the screening analysis, ranking criteria, and listing of candidate reservoirs. The economic and environmental aspects of heavy oil recovery are included in appendices to this volume. This study provides an extensive basis for heavy oil development, but should be extended to include carbonate reservoirs and tar sands. It is imperative to look at heavy oil reservoirs and projects on an individual basis; it was discovered that operators, and industrial and government analysts will lump heavy oil reservoirs as poor producers, however, it was found that upon detailed analysis, a large number, so categorized, were producing very well. A study also should be conducted on abandoned reservoirs. To utilize heavy oil, refiners will have to add various unit operations to their processes, such as hydrotreaters and hydrodesulfurizers and will require, in most cases, a lighter blending stock. A big problem in producing heavy oil is that of regulation; specifically, it was found that the regulatory constraints are so fluid and changing that one cannot settle on a favorable recovery and production plan with enough confidence in the regulatory requirements to commit capital to the project.

  5. Optimizing Environmental Flow Operation Rules based on Explicit IHA Constraints (United States)

    Dongnan, L.; Wan, W.; Zhao, J.


    Multi-objective operation of reservoirs are increasingly asked to consider the environmental flow to support ecosystem health. Indicators of Hydrologic Alteration (IHA) is widely used to describe environmental flow regimes, but few studies have explicitly formulated it into optimization models and thus is difficult to direct reservoir release. In an attempt to incorporate the benefit of environmental flow into economic achievement, a two-objective reservoir optimization model is developed and all 33 hydrologic parameters of IHA are explicitly formulated into constraints. The benefit of economic is defined by Hydropower Production (HP) while the benefit of environmental flow is transformed into Eco-Index (EI) that combined 5 of the 33 IHA parameters chosen by principal component analysis method. Five scenarios (A to E) with different constraints are tested and solved by nonlinear programming. The case study of Jing Hong reservoir, located in the upstream of Mekong basin, China, shows: 1. A Pareto frontier is formed by maximizing on only HP objective in scenario A and on only EI objective in scenario B. 2. Scenario D using IHA parameters as constraints obtains the optimal benefits of both economic and ecological. 3. A sensitive weight coefficient is found in scenario E, but the trade-offs between HP and EI objectives are not within the Pareto frontier. 4. When the fraction of reservoir utilizable capacity reaches 0.8, both HP and EI capture acceptable values. At last, to make this modelmore conveniently applied to everyday practice, a simplified operation rule curve is extracted.

  6. Mathematical models of a liquid filtration from reservoirs

    Directory of Open Access Journals (Sweden)

    Anvarbek Meirmanov


    Full Text Available This article studies the filtration from reservoirs into porous media under gravity. We start with the exact mathematical model at the microscopic level, describing the joint motion of a liquid in reservoir and the same liquid and the elastic solid skeleton in the porous medium. Then using a homogenization procedure we derive the chain of macroscopic models from the poroelasticity equations up to the simplest Darcy's law in the porous medium and hydraulics in the reservoir.

  7. Optimising reservoir operation

    DEFF Research Database (Denmark)

    Ngo, Long le

    Anvendelse af optimeringsteknik til drift af reservoirer er blevet et væsentligt element i vandressource-planlægning og -forvaltning. Traditionelt har reservoirer været styret af heuristiske procedurer for udtag af vand, suppleret i en vis udstrækning af subjektive beslutninger. Udnyttelse af...... reservoirer involverer en lang række interessenter med meget forskellige formål (f.eks. kunstig vanding, vandkraft, vandforsyning mv.), og optimeringsteknik kan langt bedre lede frem til afbalancerede løsninger af de ofte modstridende interesser. Afhandlingen foreslår en række tiltag, hvormed traditionelle...... driftsstrategier kan erstattes af optimale strategier baseret på den nyeste udvikling indenfor computer-baserede beregninger. Hovedbidraget i afhandlingen er udviklingen af et beregningssystem, hvori en simuleringsmodel er koblet til en model for optimering af nogle udvalgte beslutningsvariable, der i særlig grad...

  8. Geothermal reservoir engineering

    CERN Document Server

    Grant, Malcolm Alister


    As nations alike struggle to diversify and secure their power portfolios, geothermal energy, the essentially limitless heat emanating from the earth itself, is being harnessed at an unprecedented rate.  For the last 25 years, engineers around the world tasked with taming this raw power have used Geothermal Reservoir Engineering as both a training manual and a professional reference.  This long-awaited second edition of Geothermal Reservoir Engineering is a practical guide to the issues and tasks geothermal engineers encounter in the course of their daily jobs. The bo

  9. Session: Reservoir Technology

    Energy Technology Data Exchange (ETDEWEB)

    Renner, Joel L.; Bodvarsson, Gudmundur S.; Wannamaker, Philip E.; Horne, Roland N.; Shook, G. Michael


    This session at the Geothermal Energy Program Review X: Geothermal Energy and the Utility Market consisted of five papers: ''Reservoir Technology'' by Joel L. Renner; ''LBL Research on the Geysers: Conceptual Models, Simulation and Monitoring Studies'' by Gudmundur S. Bodvarsson; ''Geothermal Geophysical Research in Electrical Methods at UURI'' by Philip E. Wannamaker; ''Optimizing Reinjection Strategy at Palinpinon, Philippines Based on Chloride Data'' by Roland N. Horne; ''TETRAD Reservoir Simulation'' by G. Michael Shook

  10. Nonlinearities in reservoir engineering: Enhancing quantum correlations (United States)

    Hu, Xiangming; Hu, Qingping; Li, Lingchao; Huang, Chen; Rao, Shi


    There are two decisive factors for quantum correlations in reservoir engineering, but they are strongly reversely dependent on the atom-field nonlinearities. One is the squeezing parameter for the Bogoliubov modes-mediated collective interactions, while the other is the dissipative rates for the engineered collective dissipations. Exemplifying two-level atomic ensembles, we show that the moderate nonlinearities can compromise these two factors and thus enhance remarkably two-mode squeezing and entanglement of different spin atomic ensembles or different optical fields. This suggests that the moderate nonlinearities of the two-level systems are more advantageous for applications in quantum networks associated with reservoir engineering.

  11. Relative sea level in the Western Mediterranean basin: A regional test of the ICE-7G_NA (VM7) model and a constraint on late Holocene Antarctic deglaciation (United States)

    Roy, Keven; Peltier, W. R.


    The Mediterranean Basin is a region of special interest in the study of past and present relative sea level evolution, given its location south of the ice sheets that covered large fractions of Northern Europe during the last glaciation, the large number of biological, geological and archaeological sea level indicators that have been retrieved from its coastal regions, as well as its high density of modern coastal infrastructure. Models of the Glacial Isostatic Adjustment (GIA) process provide reconstructions of past relative sea level evolution, and can be tested for validity against past sea level indicators from the region. It is demonstrated herein that the latest ICE-7G_NA (VM7) model of the GIA process, the North American component of which was refined using a full suite of geophysical observables, is able to reconcile the vast majority of uniformly analyzed relative sea level constraints available for the Western part of the Mediterranean basin, a region to which it was not tuned. We also revisit herein the previously published interpretations of relative sea level information obtained from Roman-era coastal Mediterranean "fish tanks", analyze the far-field influence of the rate of late Holocene Antarctic ice sheet melting history on the exceptionally detailed relative sea level history available from southern Tunisia, and extend the analysis to complementary constraints on the history of Antarctic ice-sheet melting available from islands in the equatorial Pacific Ocean. The analyses reported herein provide strong support for the global "exportability" of the ICE-7G_NA (VM7) model, a result that speaks directly to the ability of spherically symmetric models of the internal viscoelastic structure to explain globally distributed observations, while also identifying isolated regions of remaining misfit which will benefit from further study.

  12. Simulation of Reservoir Sediment Flushing of the Three Gorges Reservoir Using an Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Xueying Li


    Full Text Available Reservoir sedimentation and its effect on the environment are the most serious world-wide problems in water resources development and utilization today. As one of the largest water conservancy projects, the Three Gorges Reservoir (TGR has been controversial since its demonstration period, and sedimentation is the major concern. Due to the complex physical mechanisms of water and sediment transport, this study adopts the Error Back Propagation Training Artificial Neural Network (BP-ANN to analyze the relationship between the sediment flushing efficiency of the TGR and its influencing factors. The factors are determined by the analysis on 1D unsteady flow and sediment mathematical model, mainly including reservoir inflow, incoming sediment concentration, reservoir water level, and reservoir release. Considering the distinguishing features of reservoir sediment delivery in different seasons, the monthly average data from 2003, when the TGR was put into operation, to 2011 are used to train, validate, and test the BP-ANN model. The results indicate that, although the sample space is quite limited, the whole sediment delivery process can be schematized by the established BP-ANN model, which can be used to help sediment flushing and thus decrease the reservoir sedimentation.

  13. A New Method for Fracturing Wells Reservoir Evaluation in Fractured Gas Reservoir

    Directory of Open Access Journals (Sweden)

    Jianchun Guo


    Full Text Available Natural fracture is a geological phenomenon widely distributed in tight formation, and fractured gas reservoir stimulation effect mainly depends on the communication of natural fractures. Therefore it is necessary to carry out the evaluation of this reservoir and to find out the optimal natural fractures development wells. By analyzing the interactions and nonlinear relationships of the parameters, it establishes three-level index system of reservoir evaluation and proposes a new method for gas well reservoir evaluation model in fractured gas reservoir on the basis of fuzzy logic theory and multilevel gray correlation. For this method, the Gaussian membership functions to quantify the degree of every factor in the decision-making system and the multilevel gray relation to determine the weight of each parameter on stimulation effect. Finally through fuzzy arithmetic operator between multilevel weights and fuzzy evaluation matrix, score, rank, the reservoir quality, and predicted production will be gotten. Result of this new method shows that the evaluation of the production coincidence rate reaches 80%, which provides a new way for fractured gas reservoir evaluation.

  14. The Ambiguous Role of Constraints in Creativity

    DEFF Research Database (Denmark)

    Biskjær, Michael Mose; Onarheim, Balder; Wiltschnig, Stefan


    . In this paper, we explore these particular issues in two creative domains: art and engineering design. These domains vary so greatly in terms of number and types of constraints in play that we argue for considering them as opposite extremes of a continuum of levels of creative freedom. By comparing two case......-disciplinary research into the ambiguous role of constraints in creativity....

  15. Optimal Complexity in Reservoir Modeling of an Eolian Sandstone for Carbon Sequestration Simulation (United States)

    Li, S.; Zhang, Y.; Zhang, X.


    Geologic Carbon Sequestration (GCS) is a proposed means to reduce atmospheric concentrations of carbon dioxide (CO2). Given the type, abundance, and accessibility of geologic characterization data, different reservoir modeling techniques can be utilized to build a site model. However, petrophysical properties of a formation can be modeled with simplifying assumptions or with greater detail, the later requiring sophisticated modeling techniques supported by additional data. In GCS where cost of data collection needs to be minimized, will detailed (expensive) reservoir modeling efforts lead to much improved model predictive capability? Is there an optimal level of detail in the reservoir model sufficient for prediction purposes? In Wyoming, GCS into the Nugget Sandstone is proposed. This formation is a deep (>13,000 ft) saline aquifer deposited in eolian environments, exhibiting permeability heterogeneity at multiple scales. Based on a set of characterization data, this study utilizes multiple, increasingly complex reservoir modeling techniques to create a suite of reservoir models including a multiscale, non-stationary heterogeneous model conditioned to a soft depositional model (i.e., training image), a geostatistical (stationary) facies model without conditioning, a geostatistical (stationary) petrophysical model ignoring facies, and finally, a homogeneous model ignoring all aspects of sub-aquifer heterogeneity. All models are built at regional scale with a high-resolution grid (245,133,140 cells) from which a set of local simulation models (448,000 grid cells) are extracted. These are considered alternative conceptual models with which pilot-scale CO2 injection is simulated (50 year duration at 1/10 Mt per year). A computationally efficient sensitivity analysis (SA) is conducted for all models based on a Plackett-Burman Design of Experiment metric. The SA systematically varies key parameters of the models (e.g., variogram structure and principal axes of intrinsic

  16. unconventional natural gas reservoirs

    International Nuclear Information System (INIS)

    Correa G, Tomas F; Osorio, Nelson; Restrepo R, Dora P


    This work is an exploration about different unconventional gas reservoirs worldwide: coal bed methane, tight gas, shale gas and gas hydrate? describing aspects such as definition, reserves, production methods, environmental issues and economics. The overview also mentioned preliminary studies about these sources in Colombia.

  17. Parallel reservoir simulator computations

    International Nuclear Information System (INIS)

    Hemanth-Kumar, K.; Young, L.C.


    The adaptation of a reservoir simulator for parallel computations is described. The simulator was originally designed for vector processors. It performs approximately 99% of its calculations in vector/parallel mode and relative to scalar calculations it achieves speedups of 65 and 81 for black oil and EOS simulations, respectively on the CRAY C-90

  18. Mercury and methylmercury in reservoirs in Indiana (United States)

    Risch, Martin R.; Fredericksen, Amanda L.


    Mercury (Hg) is an element that occurs naturally, but evidence suggests that human activities have resulted in increased amounts being released to the atmosphere and land surface. When Hg is converted to methylmercury (MeHg) in aquatic ecosystems, MeHg accumulates and increases in the food web so that some fish contain levels which pose a health risk to humans and wildlife that consume these fish. Reservoirs unlike natural lakes, are a part of river systems that are managed for flood control. Data compiled and interpreted for six flood-control reservoirs in Indiana showed a relation between Hg transport, MeHg formation in water, and MeHg in fish that was influenced by physical, chemical, and biological differences among the reservoirs. Existing information precludes a uniform comparison of Hg and MeHg in all reservoirs in the State, but factors and conditions were identified that can indicate where and when Hg and MeHg levels in reservoirs could be highest.

  19. Sensitivity Analysis of Methane Hydrate Reservoirs: Effects of Reservoir Parameters on Gas Productivity and Economics (United States)

    Anderson, B. J.; Gaddipati, M.; Nyayapathi, L.


    This paper presents a parametric study on production rates of natural gas from gas hydrates by the method of depressurization, using CMG STARS. Seven factors/parameters were considered as perturbations from a base-case hydrate reservoir description based on Problem 7 of the International Methane Hydrate Reservoir Simulator Code Comparison Study led by the Department of Energy and the USGS. This reservoir is modeled after the inferred properties of the hydrate deposit at the Prudhoe Bay L-106 site. The included sensitivity variables were hydrate saturation, pressure (depth), temperature, bottom-hole pressure of the production well, free water saturation, intrinsic rock permeability, and porosity. A two-level (L=2) Plackett-Burman experimental design was used to study the relative effects of these factors. The measured variable was the discounted cumulative gas production. The discount rate chosen was 15%, resulting in the gas contribution to the net present value of a reservoir. Eight different designs were developed for conducting sensitivity analysis and the effects of the parameters on the real and discounted production rates will be discussed. The breakeven price in various cases and the dependence of the breakeven price on the production parameters is given in the paper. As expected, initial reservoir temperature has the strongest positive effect on the productivity of a hydrate deposit and the bottom-hole pressure in the production well has the strongest negative dependence. Also resulting in a positive correlation is the intrinsic permeability and the initial free water of the formation. Negative effects were found for initial hydrate saturation (at saturations greater than 50% of the pore space) and the reservoir porosity. These negative effects are related to the available sensible heat of the reservoir, with decreasing productivity due to decreasing available sensible heat. Finally, we conclude that for the base case reservoir, the break-even price (BEP


    Energy Technology Data Exchange (ETDEWEB)

    Scott Walker; Chris Phillips; Roy Koerner; Don Clarke; Dan Moos; Kwasi Tagbor


    This project increased recoverable waterflood reserves in slope and basin reservoirs through improved reservoir characterization and reservoir management. The particular application of this project is in portions of Fault Blocks IV and V of the Wilmington Oil Field, in Long Beach, California, but the approach is widely applicable in slope and basin reservoirs. Transferring technology so that it can be applied in other sections of the Wilmington Field and by operators in other slope and basin reservoirs is a primary component of the project. This project used advanced reservoir characterization tools, including the pulsed acoustic cased-hole logging tool, geologic three-dimensional (3-D) modeling software, and commercially available reservoir management software to identify sands with remaining high oil saturation following waterflood. Production from the identified high oil saturated sands was stimulated by recompleting existing production and injection wells in these sands using conventional means as well as a short radius redrill candidate. Although these reservoirs have been waterflooded over 40 years, researchers have found areas of remaining oil saturation. Areas such as the top sand in the Upper Terminal Zone Fault Block V, the western fault slivers of Upper Terminal Zone Fault Block V, the bottom sands of the Tar Zone Fault Block V, and the eastern edge of Fault Block IV in both the Upper Terminal and Lower Terminal Zones all show significant remaining oil saturation. Each area of interest was uncovered emphasizing a different type of reservoir characterization technique or practice. This was not the original strategy but was necessitated by the different levels of progress in each of the project activities.

  1. Constraints meet concurrency

    CERN Document Server

    Mauro, Jacopo


    This book describes the benefits that emerge when the fields of constraint programming and concurrency meet. On the one hand, constraints can be used in concurrency theory to increase the conciseness and the expressive power of concurrent languages from a pragmatic point of view. On the other hand, problems modeled by using constraints can be solved faster and more efficiently using a concurrent system. Both directions are explored providing two separate lines of development. Firstly the expressive power of a concurrent language is studied, namely Constraint Handling Rules, that supports constraints as a primitive construct. The features of this language which make it Turing powerful are shown. Then a framework is proposed to solve constraint problems that is intended to be deployed on a concurrent system. For the development of this framework the concurrent language Jolie following the Service Oriented paradigm is used. Based on this experience, an extension to Service Oriented Languages is also proposed in ...

  2. Constraint Optimization Literature Review (United States)


    constraint propagation techniques, see Bessière (2006). 3.1.3 Depth-First Search Depth-first search (also called backtracking search) is a trial-and...any constraints, the algorithm backtracks by unassigning the most recent variable binding and reassigning the variable to a different value. If a solution, so choosing the value that is least likely to cause a constraint violation reduces the chance that it will be necessary to backtrack

  3. Temporal Concurrent Constraint Programming

    DEFF Research Database (Denmark)

    Nielsen, Mogens; Palamidessi, Catuscia; Valencia, Frank Dan


    The ntcc calculus is a model of non-deterministic temporal concurrent constraint programming. In this paper we study behavioral notions for this calculus. In the underlying computational model, concurrent constraint processes are executed in discrete time intervals. The behavioral notions studied...... reflect the reactive interactions between concurrent constraint processes and their environment, as well as internal interactions between individual processes. Relationships between the suggested notions are studied, and they are all proved to be decidable for a substantial fragment of the calculus...

  4. vanA Gene Harboring Enterococcal and Non-enterococcal Isolates Expressing High Level Vancomycin and Teicoplanin Resistance Reservoired in Surface Waters. (United States)

    Nakipoğlu, Mustafa; Yilmaz, Fadime; Icgen, Bulent


    Untreated wastewaters and treated effluents even after final disinfection contain antibiotic resistant bacteria and resistance genes before they are released into surface waters. A correlation between resistant bacteria and antibiotics in surface waters has been found, as have antibiotic resistance genes. Of particular interest are vancomycin-resistant enterococci harboring vanA gene that confers high level of resistance to glycopeptide antibiotics including teicoplanin. Therefore, in this study, river water samples were analysed to investigate vancomycin- and teicoplanin-resistant bacterial isolates harboring vanA gene. Out of 290, 15 surface water isolates displayed resistance to both antibiotics. These glycopeptide resistant enterococcal and non-enterococcal isolates, identified by 16S rRNA sequencing, were found to harbor vanA gene with sequence similarities of 50 % to 100 %. The presence of D-alanine-D-lactate ligase encoded by vanA gene was also shown for all vancomycin- and teicoplanin-resistant isolates through western blot analysis. Due to reuse of treated wastewater and release of untreated wastewaters to water bodies, antibiotic resistant bacteria and resistance genes are being introduced into surface waters and present human health risks. Therefore, surface waters are not only hot spots for vanA harboring enterococcal isolates but also non-enterococcal isolates due to gene dissemination and require special scientific consideration.


    Energy Technology Data Exchange (ETDEWEB)

    Jack Bergeron; Tom Blasingame; Louis Doublet; Mohan Kelkar; George Freeman; Jeff Callard; David Moore; David Davies; Richard Vessell; Brian Pregger; Bill Dixon; Bryce Bezant


    Reservoir performance and characterization are vital parameters during the development phase of a project. Infill drilling of wells on a uniform spacing, without regard to characterization does not optimize development because it fails to account for the complex nature of reservoir heterogeneities present in many low permeability reservoirs, especially carbonate reservoirs. These reservoirs are typically characterized by: (1) large, discontinuous pay intervals; (2) vertical and lateral changes in reservoir properties; (3) low reservoir energy; (4) high residual oil saturation; and (5) low recovery efficiency. The operational problems they encounter in these types of reservoirs include: (1) poor or inadequate completions and stimulations; (2) early water breakthrough; (3) poor reservoir sweep efficiency in contacting oil throughout the reservoir as well as in the nearby well regions; (4) channeling of injected fluids due to preferential fracturing caused by excessive injection rates; and (5) limited data availability and poor data quality. Infill drilling operations only need target areas of the reservoir which will be economically successful. If the most productive areas of a reservoir can be accurately identified by combining the results of geological, petrophysical, reservoir performance, and pressure transient analyses, then this ''integrated'' approach can be used to optimize reservoir performance during secondary and tertiary recovery operations without resorting to ''blanket'' infill drilling methods. New and emerging technologies such as geostatistical modeling, rock typing, and rigorous decline type curve analysis can be used to quantify reservoir quality and the degree of interwell communication. These results can then be used to develop a 3-D simulation model for prediction of infill locations. The application of reservoir surveillance techniques to identify additional reservoir ''pay'' zones

  6. Intermittent reservoir daily-inflow prediction using lumped and ...

    Indian Academy of Sciences (India)

    cations such as flood control, drought manage- ment, optimal reservoir operation and hydropower generation. There are many studies pertaining to .... est, 49% cultivated area, 6% waste land and 4% of others (CDO 1992). The water spread area at full reservoir level is 115.36 km2 which is about 13% of the total catchment ...

  7. Seasonal and diurnal stratification in two small Zimbabwean reservoirs

    African Journals Online (AJOL)

    The shallow nature of small reservoirs and the considerable fluctuations in their water levels makes them more vulnerable to external fluxes such as daily changes in incoming short-wave solar radiation and wind runs, and hence the prevalence of diel stratification regimes. Consequently, small reservoirs are characterised ...

  8. Systemic insecticide treatment of the canine reservoir of Trypanosoma cruzi induces high levels of lethality in Triatoma infestans, a principal vector of Chagas disease. (United States)

    Loza, Ariel; Talaga, Adrianna; Herbas, Gladys; Canaviri, Ruben Jair; Cahuasiri, Thalia; Luck, Laura; Guibarra, Alvaro; Goncalves, Raquel; Pereira, Juan Antonio; Gomez, Sonia A; Picado, Albert; Messenger, Louisa Alexandra; Bern, Caryn; Courtenay, Orin


    Despite large-scale reductions in Chagas disease prevalence across Central and South America, Trypanosoma cruzi infection remains a considerable public health problem in the Gran Chaco region where vector-borne transmission persists. In these communities, peridomestic animals are major blood-meal sources for triatomines, and household presence of infected dogs increases T. cruzi transmission risk for humans. To address the pressing need for field-friendly, complementary methods to reduce triatomine infestation and interrupt T. cruzi transmission, this study evaluated the systemic activity of three commercial, oral, single dose insecticides Fluralaner (Bravecto®), Afoxolaner (NexGard®) and Spinosad (Comfortis®) in canine feed-through assays against Triatoma infestans, the principal domestic vector species in the Southern Cone of South America. Twelve healthy, outbred dogs were recruited from the Zoonosis Surveillance and Control Program in Santa Cruz, Bolivia, and randomized to three treatment groups, each containing one control and three treated dogs. Following oral drug administration, colony-reared second and third stage T. infestans instars were offered to feed on dogs for 30 min at 2, 7, 21, 34 and 51 days post-treatment. Eighty-five per cent (768/907) of T. infestans successfully blood-fed during bioassays, with significantly higher proportions of bugs becoming fully-engorged when exposed to Bravecto® treated dogs (P Fluralaner or Afoxolaner was safe and well tolerated, producing complete triatomine mortality on treated dogs over 7.3 weeks. While both drugs were highly efficacious, more bugs exposed to Fluralaner took complete blood-meals, and experienced rapid knock-down. Coupled with its longer residual activity, Fluralaner represents an ideal insecticide for development into a complementary, operationally-feasible, community-level method of reducing triatomine infestation and potentially controlling T. cruzi transmission, in the Gran Chaco region.

  9. Partial constraint satisfaction approaches for optimal operation of a hydropower system (United States)

    Ferreira, Andre R.; Teegavarapu, Ramesh S. V.


    Optimal operation models for a hydropower system using partial constraint satisfaction (PCS) approaches are proposed and developed in this study. The models use mixed integer nonlinear programming (MINLP) formulations with binary variables. The models also integrate a turbine unit commitment formulation along with water quality constraints used for evaluation of reservoir downstream water quality impairment. New PCS-based models for hydropower optimization formulations are developed using binary and continuous evaluator functions to maximize the constraint satisfaction. The models are applied to a real-life hydropower reservoir system in Brazil. Genetic Algorithms (GAs) are used to solve the optimization formulations. Decision maker's preferences towards power production targets and water quality improvements are incorporated using partial satisfaction constraints to obtain compromise operating rules for a multi-objective reservoir operation problem dominated by conflicting goals of energy production, water quality and consumptive water uses.

  10. Floodplains within reservoirs promote earlier spawning of white crappies Pomoxis annularis (United States)

    Miranda, Leandro E.; Dagel, Jonah D.; Kaczka, Levi J.; Mower, Ethan; Wigen, S. L.


    Reservoirs impounded over floodplain rivers are unique because they may include within their upper reaches extensive shallow water stored over preexistent floodplains. Because of their relatively flat topography and riverine origin, floodplains in the upper reaches of reservoirs provide broad expanses of vegetation within a narrow range of reservoir water levels. Elsewhere in the reservoir, topography creates a band of shallow water along the contour of the reservoir where vegetation often does not grow. Thus, as water levels rise, floodplains may be the first vegetated habitats inundated within the reservoir. We hypothesized that shallow water in reservoir floodplains would attract spawning white crappies Pomoxis annularis earlier than reservoir embayments. Crappie relative abundance over five years in floodplains and embayments of four reservoirs increased as spawning season approached, peaked, and decreased as fish exited shallow water. Relative abundance peaked earlier in floodplains than embayments, and the difference was magnified with higher water levels. Early access to suitable spawning habitat promotes earlier spawning and may increase population fitness. Recognition of the importance of reservoir floodplains, an understanding of how reservoir water levels can be managed to provide timely connectivity to floodplains, and conservation of reservoir floodplains may be focal points of environmental management in reservoirs.

  11. Chalk reservoirs of the North Sea

    International Nuclear Information System (INIS)

    Hardman, R.F.P.


    The amount of clay in the chalk, whether primary or secondary, is the factor of greatest importance in determining whether chalk has the capability of forming a reservoir rock or not. It has been empirically observed that the less the clay content the better the resevoir and as has been remarked earlier, the amount of clay in the Chalk can be closely correlated with sea level. changes. Where other factors are either absent or of only minor importance, the effect of clay is most clearly seen. A good example is well N-2 in Danish waters. It is concluded that in N-2 clay is the dominant control on reservoir quality. (EG)

  12. Mechanisms of HIV persistence in HIV reservoirs. (United States)

    Mzingwane, Mayibongwe L; Tiemessen, Caroline T


    The establishment and maintenance of HIV reservoirs that lead to persistent viremia in patients on antiretroviral drugs remains the greatest challenge of the highly active antiretroviral therapy era. Cellular reservoirs include resting memory CD4+ T lymphocytes, implicated as the major HIV reservoir, having a half-life of approximately 44 months while this is less than 6 hours for HIV in plasma. In some individuals, persistent viremia consists of invariant HIV clones not detected in circulating resting CD4+ T lymphocytes suggesting other possible sources of residual viremia. Some anatomical reservoirs that may harbor such cells include the brain and the central nervous system, the gastrointestinal tract and the gut-associated lymphoid tissue and other lymphoid organs, and the genital tract. The presence of immune cells and other HIV susceptible cells, occurring in differing compositions in anatomical reservoirs, coupled with variable and poor drug penetration that results in suboptimal drug concentrations in some sites, are all likely factors that fuel the continued low-level replication and persistent viremia during treatment. Latently, HIV-infected CD4+ T cells harboring replication-competent virus, HIV cell-to-cell spread, and HIV-infected T cell homeostatic proliferation due to chronic immune activation represent further drivers of this persistent HIV viremia during highly active antiretroviral therapy. Copyright © 2017 John Wiley & Sons, Ltd.

  13. Physical modelling of the Akkajaure reservoir

    Directory of Open Access Journals (Sweden)

    J. Sahlberg


    Full Text Available This paper describes the seasonal temperature development in the Akkajaure reservoir, one of the largest Swedish reservoirs. It lies in the headwaters of the river Lulealven in northern Sweden; it is 60 km long and 5 km wide with a maximum depth of 92 m. The maximum allowed variation in surface water level is 30 m. The temperature field in the reservoir is important for many biochemical processes. A one-dimensional lake model of the Akkajaure reservoir is developed from a lake model by Sahlberg (1983 and 1988. The dynamic eddy viscosity is calculated by a two equation turbulence model, a k–ε model and the hypolimnic eddy diffusivity formulation which is a function of the stability frequency (Hondzo et al., 1993. A comparison between calculated and measured temperature profiles showed a maximum discrepancy of 0.5–1.0°C over the period 1999-2002. Except for a few days in summer, the water temperature is vertically homogeneous. Over that period of years, a weak stratification of temperature occurred on only one to two weeks a year on different dates in July and August. This will have biological consequences. Keywords: temperature profile,reservoir, 1-D lake model, stratification, Sweden

  14. Temporal Concurrent Constraint Programming

    DEFF Research Database (Denmark)

    Nielsen, Mogens; Valencia Posso, Frank Dan


    The ntcc calculus is a model of non-deterministic temporal concurrent constraint programming. In this paper we study behavioral notions for this calculus. In the underlying computational model, concurrent constraint processes are executed in discrete time intervals. The behavioral notions studied...

  15. Theory of Constraints (TOC)

    DEFF Research Database (Denmark)

    Michelsen, Aage U.


    Tankegangen bag Theory of Constraints samt planlægningsprincippet Drum-Buffer-Rope. Endvidere skitse af The Thinking Process.......Tankegangen bag Theory of Constraints samt planlægningsprincippet Drum-Buffer-Rope. Endvidere skitse af The Thinking Process....

  16. Credit Constraints in Education (United States)

    Lochner, Lance; Monge-Naranjo, Alexander


    We review studies of the impact of credit constraints on the accumulation of human capital. Evidence suggests that credit constraints have recently become important for schooling and other aspects of households' behavior. We highlight the importance of early childhood investments, as their response largely determines the impact of credit…

  17. Evaluating Distributed Timing Constraints

    DEFF Research Database (Denmark)

    Kristensen, C.H.; Drejer, N.


    In this paper we describe a solution to the problem of implementing time-optimal evaluation of timing constraints in distributed real-time systems.......In this paper we describe a solution to the problem of implementing time-optimal evaluation of timing constraints in distributed real-time systems....

  18. Work reservoirs in thermodynamics (United States)

    Anacleto, Joaquim


    We stress the usefulness of the work reservoir in the formalism of thermodynamics, in particular in the context of the first law. To elucidate its usefulness, the formalism is then applied to the Joule expansion and other peculiar and instructive experimental situations, clarifying the concepts of configuration and dissipative work. The ideas and discussions presented in this study are primarily intended for undergraduate students, but they might also be useful to graduate students, researchers and teachers.

  19. Constraints in Quantum Geometrodynamics (United States)

    Gentle, Adrian P.; George, Nathan D.; Miller, Warner A.; Kheyfets, Arkady

    We compare different treatments of the constraints in canonical quantum gravity. The standard approach on the superspace of 3-geometries treats the constraints as the sole carriers of the dynamic content of the theory, thus rendering the traditional dynamical equations obsolete. Quantization of the constraints in both the Dirac and ADM square root Hamiltonian approaches leads to the well known problems of time evolution. These problems of time are of both an interpretational and technical nature. In contrast, the geometrodynamic quantization procedure on the superspace of the true dynamical variables separates the issues of quantization from the enforcement of the constraints. The resulting theory takes into account states that are off-shell with respect to the constraints, and thus avoids the problems of time. We develop, for the first time, the geometrodynamic quantization formalism in a general setting and show that it retains all essential features previously illustrated in the context of homogeneous cosmologies.

  20. Facies-constrained FWI: Toward application to reservoir characterization

    KAUST Repository

    Kamath, Nishant


    The most common approach to obtaining reservoir properties from seismic data exploits the amplitude variation with offset response of reflected waves. However, structural complexity and errors in the velocity model can severely reduce the quality of the inverted results. Full-waveform inversion (FWI) has shown a lot of promise in obtaining high-resolution velocity models for depth imaging. We propose supplementing FWI with rock-physics constraints obtained from borehole data to invert for reservoir properties. The constraints are imposed by adding appropriately weighted regularization terms to the objective function. The advantages of this technique over conventional FWI algorithms are shown by conducting synthetic tests for both isotropic and VTI (transversely isotropic with a vertical symmetry axis) models. The medium parameterization for FWI is selected using radiation (scattering) patterns of perturbations in the model parameters.

  1. Constraints to increased sludge utilization

    International Nuclear Information System (INIS)

    Pound, C.E.; Bory, L.D.


    The management and disposition of municipal sewage sludge is a growing problem as secondary treatment plants are completed to meet Clean Water Act standards. The prohibition of ocean dumping, the increased cost and difficulty to secure and operate sludge landfills, and the high energy costs of dewatering and incineration should all contribute to an increase in land application. However, land application and other beneficial use alternatives, such as give away/sale, account for only 20% of the 12 m/day tons of sludge produced nationally. This result can in part be attributed to public health, institutional, and legal constraints on implementing land application systems. Public health constraints include contaminants in sludge which may pose a risk to human health. Much current controversy about the safety of applying sludge to agricultural land on which food chain crops are grown focuses on heavy metals, especially cadmium. But proposed federal and state regulation of cadmium concentrations in sludge, at levels where human health risk has not been demonstrated, may limit utilization by land application. State operating rules and other administrative controls over sludge application are among the institutional constraints. Since land is an essential element in a land application system, securing adequate and suitable land involves legal constraints. Involuntary acquisition and zoning procedures can delay and frustrate land application programs. Securing indemnity insurance for possible damage to land to which sludge is applied has also been an obstacle to implementation of utilization programs

  2. Toward making the constraint hypersurface an attractor in free evolution

    International Nuclear Information System (INIS)

    Fiske, David R.


    When constructing numerical solutions to systems of evolution equations subject to a constraint, one must decide what role the constraint equations will play in the evolution system. In one popular choice, known as free evolution, a simulation is treated as a Cauchy problem, with the initial data constructed to satisfy the constraint equations. This initial data are then evolved via the evolution equations with no further enforcement of the constraint equations. The evolution, however, via the discretized evolution equations introduce constraint violating modes at the level of truncation error, and these constraint violating modes will behave in a formalism dependent way. This paper presents a generic method for incorporating the constraint equations into the evolution equations so that the off-constraint dynamics are biased toward the constraint satisfying solutions

  3. Advantageous Reservoir Characterization Technology in Extra Low Permeability Oil Reservoirs

    Directory of Open Access Journals (Sweden)

    Yutian Luo


    Full Text Available This paper took extra low permeability reservoirs in Dagang Liujianfang Oilfield as an example and analyzed different types of microscopic pore structures by SEM, casting thin sections fluorescence microscope, and so on. With adoption of rate-controlled mercury penetration, NMR, and some other advanced techniques, based on evaluation parameters, namely, throat radius, volume percentage of mobile fluid, start-up pressure gradient, and clay content, the classification and assessment method of extra low permeability reservoirs was improved and the parameter boundaries of the advantageous reservoirs were established. The physical properties of reservoirs with different depth are different. Clay mineral variation range is 7.0%, and throat radius variation range is 1.81 μm, and start pressure gradient range is 0.23 MPa/m, and movable fluid percentage change range is 17.4%. The class IV reservoirs account for 9.56%, class II reservoirs account for 12.16%, and class III reservoirs account for 78.29%. According to the comparison of different development methods, class II reservoir is most suitable for waterflooding development, and class IV reservoir is most suitable for gas injection development. Taking into account the gas injection in the upper section of the reservoir, the next section of water injection development will achieve the best results.

  4. Contestation in multi-level party systems with institutional constraints: A look at ethnically divided countries in Central and Eastern Europe

    DEFF Research Database (Denmark)

    Bochsler, Daniel


    of party systems restricts party plurality at the local or regional level, non-partisan candidates and groups will emerge. Hypotheses are tested, looking at the political representation and plurality of representation in minority regions in Central and Eastern Europe, investigating ethnic minorities...... in Romania, Slovakia, Moldova, and Macedonia. The effect of national electoral laws in these countries allows for substantial variation in its degree of restrictiveness...

  5. Field Demonstration of Horizontal Infill Drilling Using Cost-effective Integrated Reservoir Modeling--Mississippian Carbonates, Central Kansas

    Energy Technology Data Exchange (ETDEWEB)

    Saibal Bhattacharya


    Mississippian carbonate reservoirs have produced in excess of 1 billion barrels of oil in Kansas accounting for over 16% of the state's production. With declining production from other age reservoirs, the contribution of Mississippian reservoirs to Kansas's oil production has risen to 43% as of 2004. However, solution-enhanced features such as vertical shale intervals extending from the karst erosional surface at the top introduce complexities/compartmentalizations in Mississippian carbonate reservoirs. Coupled with this, strong water drives charge many of these reservoirs resulting in limited drainage from vertical wells due to high water cuts after an initial period of low water production. Moreover, most of these fields are operated by small independent operators without access to the knowledge bank of modern research in field characterization and exploitation/development practices. Thus, despite increasing importance of Mississippian fields to Kansas production, these fields are beset with low recovery factors and high abandonment rates leaving significant resources in the ground. Worldwide, horizontal infill wells have been successful in draining compartmentalized reservoirs with limited pressure depletion. The intent of this project was to demonstrate the application of horizontal wells to successfully exploit the remaining potential in mature Mississippian fields of the mid-continent. However, it is of critical importance that for horizontal wells to be economically successful, they must be selectively targeted. This project demonstrated the application of initial and secondary screening methods, based on publicly available data, to quickly shortlist fields in a target area for detailed studies to evaluate their potential to infill horizontal well applications. Advanced decline curve analyses were used to estimate missing well-level production data and to verify if the well produced under unchanging bottom-hole conditions--two commonly occurring

  6. Scalable and Robust BDDC Preconditioners for Reservoir and Electromagnetics Modeling

    KAUST Repository

    Zampini, S.


    The purpose of the study is to show the effectiveness of recent algorithmic advances in Balancing Domain Decomposition by Constraints (BDDC) preconditioners for the solution of elliptic PDEs with highly heterogeneous coefficients, and discretized by means of the finite element method. Applications to large linear systems generated by div- and curl- conforming finite elements discretizations commonly arising in the contexts of modelling reservoirs and electromagnetics will be presented.

  7. [Ultraviolet-visible (UV-Vis) and fluorescence spectral characteristics of dissolved organic matter (DOM) in soils of water-level fluctuation zones of the Three Gorges Reservoir Region]. (United States)

    Gao, Jie; Jiang Tao; Li, Lu-lu; Chen, Xue-shuang; Wei, Shi-qiang; Wang, Ding-yong; Yan, Jin- long; Zhao, Zheng


    Ultraviolet-visible (UV-Vis) absorption spectroscopy and three-dimensional fluorescence spectroscopy, combined with fluorescence regional integration were conducted to investigate the geochemical characteristics of DOM extracted from soils of water-level fluctuation zones of the Three Gorges Reservoir Region. The results showed that the average CDOM concentrations in soils were in order of Zhongxian > Fengdu > Fuling > Wanzhou > Wushan > Yunyang > Fengjie > Kaixian. Additionally, in Zhongxian, Fengdu and Fuling, the CDOM concentration [a (355)], aromaticity (SUVA254) and hydrophobicity (SUVA260) were all much higher than those at the other sampling sites, but the humification index (HIX) was lower. Four fluorophores were observed in all soil DOM samples, including three humic-like fluorescence peaks (A, C and M respectively) and one tryptophan-like fluorescence peak (T). Proportion of fluorescence regional integration of ultraviolet region humic-like A fluorophore was the highest as compared with the others. More importantly, tryptophan-like fluorophore (T) and a(355) showed significant correlation (r = 0.674, P < 0.01), indicating the variance of CDOM concentration was possibly dependent on T fluorophore. Meanwhile, the total integrated fluorescence intensity(TOT) of 3D- EEM was an appropriate parameter to characterize the total contributions of fluorophores in DOM. Furthermore, the humification degree of DOM in soils was low in comparison with higher biological availability. Conclusively it seemed that the influence of "alternation of wetting and drying" resulted from water-level fluctuation on the geochemical characteristics of soil DOM was not significant as expected. It might be related to local agricultural activity, littoral plant growth and DOM mineralization process.

  8. Constraint-based reachability

    Directory of Open Access Journals (Sweden)

    Arnaud Gotlieb


    Full Text Available Iterative imperative programs can be considered as infinite-state systems computing over possibly unbounded domains. Studying reachability in these systems is challenging as it requires to deal with an infinite number of states with standard backward or forward exploration strategies. An approach that we call Constraint-based reachability, is proposed to address reachability problems by exploring program states using a constraint model of the whole program. The keypoint of the approach is to interpret imperative constructions such as conditionals, loops, array and memory manipulations with the fundamental notion of constraint over a computational domain. By combining constraint filtering and abstraction techniques, Constraint-based reachability is able to solve reachability problems which are usually outside the scope of backward or forward exploration strategies. This paper proposes an interpretation of classical filtering consistencies used in Constraint Programming as abstract domain computations, and shows how this approach can be used to produce a constraint solver that efficiently generates solutions for reachability problems that are unsolvable by other approaches.

  9. Two Monthly Continuous Dynamic Model Based on Nash Bargaining Theory for Conflict Resolution in Reservoir System.

    Directory of Open Access Journals (Sweden)

    Mehran Homayounfar

    Full Text Available So far many optimization models based on Nash Bargaining Theory associated with reservoir operation have been developed. Most of them have aimed to provide practical and efficient solutions for water allocation in order to alleviate conflicts among water users. These models can be discussed from two viewpoints: (i having a discrete nature; and (ii working on an annual basis. Although discrete dynamic game models provide appropriate reservoir operator policies, their discretization of variables increases the run time and causes dimensionality problems. In this study, two monthly based non-discrete optimization models based on the Nash Bargaining Solution are developed for a reservoir system. In the first model, based on constrained state formulation, the first and second moments (mean and variance of the state variable (water level in the reservoir is calculated. Using moment equations as the constraint, the long-term utility of the reservoir manager and water users are optimized. The second model is a dynamic approach structured based on continuous state Markov decision models. The corresponding solution based on the collocation method is structured for a reservoir system. In this model, the reward function is defined based on the Nash Bargaining Solution. Indeed, it is used to yield equilibrium in every proper sub-game, thereby satisfying the Markov perfect equilibrium. Both approaches are applicable for water allocation in arid and semi-arid regions. A case study was carried out at the Zayandeh-Rud river basin located in central Iran to identify the effectiveness of the presented methods. The results are compared with the results of an annual form of dynamic game, a classical stochastic dynamic programming model (e.g. Bayesian Stochastic Dynamic Programming model, BSDP, and a discrete stochastic dynamic game model (PSDNG. By comparing the results of alternative methods, it is shown that both models are capable of tackling conflict issues in

  10. Two Monthly Continuous Dynamic Model Based on Nash Bargaining Theory for Conflict Resolution in Reservoir System. (United States)

    Homayounfar, Mehran; Zomorodian, Mehdi; Martinez, Christopher J; Lai, Sai Hin


    So far many optimization models based on Nash Bargaining Theory associated with reservoir operation have been developed. Most of them have aimed to provide practical and efficient solutions for water allocation in order to alleviate conflicts among water users. These models can be discussed from two viewpoints: (i) having a discrete nature; and (ii) working on an annual basis. Although discrete dynamic game models provide appropriate reservoir operator policies, their discretization of variables increases the run time and causes dimensionality problems. In this study, two monthly based non-discrete optimization models based on the Nash Bargaining Solution are developed for a reservoir system. In the first model, based on constrained state formulation, the first and second moments (mean and variance) of the state variable (water level in the reservoir) is calculated. Using moment equations as the constraint, the long-term utility of the reservoir manager and water users are optimized. The second model is a dynamic approach structured based on continuous state Markov decision models. The corresponding solution based on the collocation method is structured for a reservoir system. In this model, the reward function is defined based on the Nash Bargaining Solution. Indeed, it is used to yield equilibrium in every proper sub-game, thereby satisfying the Markov perfect equilibrium. Both approaches are applicable for water allocation in arid and semi-arid regions. A case study was carried out at the Zayandeh-Rud river basin located in central Iran to identify the effectiveness of the presented methods. The results are compared with the results of an annual form of dynamic game, a classical stochastic dynamic programming model (e.g. Bayesian Stochastic Dynamic Programming model, BSDP), and a discrete stochastic dynamic game model (PSDNG). By comparing the results of alternative methods, it is shown that both models are capable of tackling conflict issues in water allocation

  11. The Economic Benefits Of Multipurpose Reservoirs In The United States- Federal Hydropower Fleet

    Energy Technology Data Exchange (ETDEWEB)

    Hadjerioua, Boualem [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Witt, Adam M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Stewart, Kevin M. [Dept. of Energy (DOE), Washington DC (United States). Office of Energy Efficiency and Renewable Energy (EERE); Bonnet Acosta, Marisol [Dept. of Energy (DOE), Washington DC (United States). Office of Energy Efficiency and Renewable Energy (EERE); Mobley, Miles [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)


    The United States is home to over 80,000 dams, of which approximately 3% are equipped with hydroelectric generating capabilities. When a dam serves as a hydropower facility, it provides a variety of energy services that range from clean, reliable power generation to load balancing that supports grid stability. In most cases, the benefits of dams and their associated reservoirs go far beyond supporting the nation s energy demand. As evidenced by the substantial presence of non-powered dams with the ability to store water in large capacities, the primary purpose of a dam may not be hydropower, but rather one of many other purposes. A dam and reservoir may support navigation, recreation, flood control, irrigation, and water supply, with each multipurpose benefit providing significant social and economic impacts on a local, regional, and national level. When hydropower is one of the services provided by a multipurpose reservoir, it is then part of an integrated system of competing uses. Operating rules, management practices, consumer demands, and environmental constraints must all be balanced to meet the multipurpose project s objectives. When federal dams are built, they are authorized by Congress to serve one or more functions. Legislation such as the Water Resources Development Act regulates the operation of the facility in order to coordinate the authorized uses and ensure the dam s intended objectives are being met. While multipurpose reservoirs account for billions of dollars in contributions to National Economic Development (NED) every year, no attempt has been made to evaluate their benefits on a national scale. This study is an on-going work conducted by Oak Ridge National Laboratory in an effort to estimate the economic benefits of multipurpose hydropower reservoirs in the United States. Given the important role that federal hydropower plays in the U.S., the first focus of this research will target the three main federal hydropower owners Tennessee Valley

  12. Integrating gravimetric and interferometric synthetic aperture radar data for enhancing reservoir history matching of carbonate gas and volatile oil reservoirs

    KAUST Repository

    Katterbauer, Klemens


    Reservoir history matching is assuming a critical role in understanding reservoir characteristics, tracking water fronts, and forecasting production. While production data have been incorporated for matching reservoir production levels and estimating critical reservoir parameters, the sparse spatial nature of this dataset limits the efficiency of the history matching process. Recently, gravimetry techniques have significantly advanced to the point of providing measurement accuracy in the microgal range and consequently can be used for the tracking of gas displacement caused by water influx. While gravity measurements provide information on subsurface density changes, i.e., the composition of the reservoir, these data do only yield marginal information about temporal displacements of oil and inflowing water. We propose to complement gravimetric data with interferometric synthetic aperture radar surface deformation data to exploit the strong pressure deformation relationship for enhancing fluid flow direction forecasts. We have developed an ensemble Kalman-filter-based history matching framework for gas, gas condensate, and volatile oil reservoirs, which synergizes time-lapse gravity and interferometric synthetic aperture radar data for improved reservoir management and reservoir forecasts. Based on a dual state-parameter estimation algorithm separating the estimation of static reservoir parameters from the dynamic reservoir parameters, our numerical experiments demonstrate that history matching gravity measurements allow monitoring the density changes caused by oil-gas phase transition and water influx to determine the saturation levels, whereas the interferometric synthetic aperture radar measurements help to improve the forecasts of hydrocarbon production and water displacement directions. The reservoir estimates resulting from the dual filtering scheme are on average 20%-40% better than those from the joint estimation scheme, but require about a 30% increase in

  13. Geothermal reservoir management

    Energy Technology Data Exchange (ETDEWEB)

    Scherer, C.R.; Golabi, K.


    The optimal management of a hot water geothermal reservoir was considered. The physical system investigated includes a three-dimensional aquifer from which hot water is pumped and circulated through a heat exchanger. Heat removed from the geothermal fluid is transferred to a building complex or other facility for space heating. After passing through the heat exchanger, the (now cooled) geothermal fluid is reinjected into the aquifer. This cools the reservoir at a rate predicted by an expression relating pumping rate, time, and production hole temperature. The economic model proposed in the study maximizes discounted value of energy transferred across the heat exchanger minus the discounted cost of wells, equipment, and pumping energy. The real value of energy is assumed to increase at r percent per year. A major decision variable is the production or pumping rate (which is constant over the project life). Other decision variables in this optimization are production timing, reinjection temperature, and the economic life of the reservoir at the selected pumping rate. Results show that waiting time to production and production life increases as r increases and decreases as the discount rate increases. Production rate decreases as r increases and increases as the discount rate increases. The optimal injection temperature is very close to the temperature of the steam produced on the other side of the heat exchanger, and is virtually independent of r and the discount rate. Sensitivity of the decision variables to geohydrological parameters was also investigated. Initial aquifer temperature and permeability have a major influence on these variables, although aquifer porosity is of less importance. A penalty was considered for production delay after the lease is granted.

  14. Resources, constraints and capabilities

    NARCIS (Netherlands)

    Dhondt, S.; Oeij, P.R.A.; Schröder, A.


    Human and financial resources as well as organisational capabilities are needed to overcome the manifold constraints social innovators are facing. To unlock the potential of social innovation for the whole society new (social) innovation friendly environments and new governance structures

  15. Advances in photonic reservoir computing (United States)

    Van der Sande, Guy; Brunner, Daniel; Soriano, Miguel C.


    We review a novel paradigm that has emerged in analogue neuromorphic optical computing. The goal is to implement a reservoir computer in optics, where information is encoded in the intensity and phase of the optical field. Reservoir computing is a bio-inspired approach especially suited for processing time-dependent information. The reservoir's complex and high-dimensional transient response to the input signal is capable of universal computation. The reservoir does not need to be trained, which makes it very well suited for optics. As such, much of the promise of photonic reservoirs lies in their minimal hardware requirements, a tremendous advantage over other hardware-intensive neural network models. We review the two main approaches to optical reservoir computing: networks implemented with multiple discrete optical nodes and the continuous system of a single nonlinear device coupled to delayed feedback.

  16. Dynamics and causality constraints

    International Nuclear Information System (INIS)

    Sousa, Manoelito M. de


    The physical meaning and the geometrical interpretation of causality implementation in classical field theories are discussed. Causality in field theory are kinematical constraints dynamically implemented via solutions of the field equation, but in a limit of zero-distance from the field sources part of these constraints carries a dynamical content that explains old problems of classical electrodynamics away with deep implications to the nature of physicals interactions. (author)

  17. Vocabulary Constraint on Texts

    Directory of Open Access Journals (Sweden)

    C. Sutarsyah


    Full Text Available This case study was carried out in the English Education Department of State University of Malang. The aim of the study was to identify and describe the vocabulary in the reading text and to seek if the text is useful for reading skill development. A descriptive qualitative design was applied to obtain the data. For this purpose, some available computer programs were used to find the description of vocabulary in the texts. It was found that the 20 texts containing 7,945 words are dominated by low frequency words which account for 16.97% of the words in the texts. The high frequency words occurring in the texts were dominated by function words. In the case of word levels, it was found that the texts have very limited number of words from GSL (General Service List of English Words (West, 1953. The proportion of the first 1,000 words of GSL only accounts for 44.6%. The data also show that the texts contain too large proportion of words which are not in the three levels (the first 2,000 and UWL. These words account for 26.44% of the running words in the texts.  It is believed that the constraints are due to the selection of the texts which are made of a series of short-unrelated texts. This kind of text is subject to the accumulation of low frequency words especially those of content words and limited of words from GSL. It could also defeat the development of students' reading skills and vocabulary enrichment.

  18. Momentum constraint relaxation

    International Nuclear Information System (INIS)

    Marronetti, Pedro


    Full relativistic simulations in three dimensions invariably develop runaway modes that grow exponentially and are accompanied by violations of the Hamiltonian and momentum constraints. Recently, we introduced a numerical method (Hamiltonian relaxation) that greatly reduces the Hamiltonian constraint violation and helps improve the quality of the numerical model. We present here a method that controls the violation of the momentum constraint. The method is based on the addition of a longitudinal component to the traceless extrinsic curvature A ij -tilde, generated by a vector potential w i , as outlined by York. The components of w i are relaxed to solve approximately the momentum constraint equations, slowly pushing the evolution towards the space of solutions of the constraint equations. We test this method with simulations of binary neutron stars in circular orbits and show that it effectively controls the growth of the aforementioned violations. We also show that a full numerical enforcement of the constraints, as opposed to the gentle correction of the momentum relaxation scheme, results in the development of instabilities that stop the runs shortly

  19. High resolution reservoir geological modelling using outcrop information

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Changmin; Lin Kexiang; Liu Huaibo [Jianghan Petroleum Institute, Hubei (China)] [and others


    This is China`s first case study of high resolution reservoir geological modelling using outcrop information. The key of the modelling process is to build a prototype model and using the model as a geological knowledge bank. Outcrop information used in geological modelling including seven aspects: (1) Determining the reservoir framework pattern by sedimentary depositional system and facies analysis; (2) Horizontal correlation based on the lower and higher stand duration of the paleo-lake level; (3) Determining the model`s direction based on the paleocurrent statistics; (4) Estimating the sandbody communication by photomosaic and profiles; (6) Estimating reservoir properties distribution within sandbody by lithofacies analysis; and (7) Building the reservoir model in sandbody scale by architectural element analysis and 3-D sampling. A high resolution reservoir geological model of Youshashan oil field has been built by using this method.

  20. Encapsulated microsensors for reservoir interrogation

    Energy Technology Data Exchange (ETDEWEB)

    Scott, Eddie Elmer; Aines, Roger D.; Spadaccini, Christopher M.


    In one general embodiment, a system includes at least one microsensor configured to detect one or more conditions of a fluidic medium of a reservoir; and a receptacle, wherein the receptacle encapsulates the at least one microsensor. In another general embodiment, a method include injecting the encapsulated at least one microsensor as recited above into a fluidic medium of a reservoir; and detecting one or more conditions of the fluidic medium of the reservoir.

  1. Data Assimilation under Geological Constraints

    NARCIS (Netherlands)

    Sebacher, B.M.


    An important key in reservoirs engineering is the development of reliable reservoir models with high predictive capacity of production behavior in the existing and new drilled wells. The reservoir predictability is the starting point for guiding the production plan to an optimum. In order to achieve

  2. Decision Support System for Reservoir Management and Operation in Africa (United States)

    Navar, D. A.


    Africa is currently experiencing a surge in dam construction for flood control, water supply and hydropower production, but ineffective reservoir management has caused problems in the region, such as water shortages, flooding and loss of potential hydropower generation. Our research aims to remedy ineffective reservoir management by developing a novel Decision Support System(DSS) to equip water managers with a technical planning tool based on the state of the art in hydrological sciences. The DSS incorporates a climate forecast model, a hydraulic model of the watershed, and an optimization model to effectively plan for the operation of a system of cascade large-scale reservoirs for hydropower production, while treating water supply and flood control as constraints. Our team will use the newly constructed hydropower plants in the Omo Gibe basin of Ethiopia as the test case. Using the basic HIDROTERM software developed in Brazil, the General Algebraic Modeling System (GAMS) utilizes a combination of linear programing (LP) and non-linear programming (NLP) in conjunction with real time hydrologic and energy demand data to optimize the monthly and daily operations of the reservoir system. We compare the DSS model results with the current reservoir operating policy used by the water managers of that region. We also hope the DSS will eliminate the current dangers associated with the mismanagement of large scale water resources projects in Africa.

  3. Misconceptions and constraints

    International Nuclear Information System (INIS)

    Whitten, M.; Mahon, R.


    In theory, the sterile insect technique (SIT) is applicable to a wide variety of invertebrate pests. However, in practice, the approach has been successfully applied to only a few major pests. Chapters in this volume address possible reasons for this discrepancy, e.g. Klassen, Lance and McInnis, and Robinson and Hendrichs. The shortfall between theory and practice is partly due to the persistence of some common misconceptions, but it is mainly due to one constraint, or a combination of constraints, that are biological, financial, social or political in nature. This chapter's goal is to dispel some major misconceptions, and view the constraints as challenges to overcome, seeing them as opportunities to exploit. Some of the common misconceptions include: (1) released insects retain residual radiation, (2) females must be monogamous, (3) released males must be fully sterile, (4) eradication is the only goal, (5) the SIT is too sophisticated for developing countries, and (6) the SIT is not a component of an area-wide integrated pest management (AW-IPM) strategy. The more obvious constraints are the perceived high costs of the SIT, and the low competitiveness of released sterile males. The perceived high up-front costs of the SIT, their visibility, and the lack of private investment (compared with alternative suppression measures) emerge as serious constraints. Failure to appreciate the true nature of genetic approaches, such as the SIT, may pose a significant constraint to the wider adoption of the SIT and other genetically-based tactics, e.g. transgenic genetically modified organisms (GMOs). Lack of support for the necessary underpinning strategic research also appears to be an important constraint. Hence the case for extensive strategic research in ecology, population dynamics, genetics, and insect behaviour and nutrition is a compelling one. Raising the competitiveness of released sterile males remains the major research objective of the SIT. (author)

  4. [Hematophagous bats as reservoirs of rabies]. (United States)

    Scheffer, Karin Corrêa; Iamamoto, Keila; Asano, Karen Miyuki; Mori, Enio; Estevez Garcia, Andrea Isabel; Achkar, Samira M; Fahl, Williande Oliveira


    Rabies continues to be a challenge for public health authorities and a constraint to the livestock industry in Latin America. Wild and domestic canines and vampire bats are the main transmitter species and reservoirs of the disease. Currently, variations observed in the epidemiological profile of rabies, where the species of hematophagous bat Desmodus rotundus constitutes the main transmitting species. Over the years, knowledge has accumulated about the ecology, biology and behavior of this species and the natural history of rabies, which should lead to continuous development of methods of population control of d. Rotundus as well as prevention and diagnostic tools for rabies. Ecological relationships of this species with other hematophagous and non-hematophagous bats is unknown, and there is much room for improvement in reporting systems and surveillance, as well as creating greater awareness among the farming community. Understanding the impact of human-induced environmental changes on the rabies virus in bats should be cause for further investigation. This will require a combination of field studies with mathematical models and new diagnostic tools. This review aims to present the most relevant issues on the role of hematophagous bats as reservoirs and transmitters of the rabies virus.

  5. Reservoir Simulations of Low-Temperature Geothermal Reservoirs (United States)

    Bedre, Madhur Ganesh

    The eastern United States generally has lower temperature gradients than the western United States. However, West Virginia, in particular, has higher temperature gradients compared to other eastern states. A recent study at Southern Methodist University by Blackwell et al. has shown the presence of a hot spot in the eastern part of West Virginia with temperatures reaching 150°C at a depth of between 4.5 and 5 km. This thesis work examines similar reservoirs at a depth of around 5 km resembling the geology of West Virginia, USA. The temperature gradients used are in accordance with the SMU study. In order to assess the effects of geothermal reservoir conditions on the lifetime of a low-temperature geothermal system, a sensitivity analysis study was performed on following seven natural and human-controlled parameters within a geothermal reservoir: reservoir temperature, injection fluid temperature, injection flow rate, porosity, rock thermal conductivity, water loss (%) and well spacing. This sensitivity analysis is completed by using ‘One factor at a time method (OFAT)’ and ‘Plackett-Burman design’ methods. The data used for this study was obtained by carrying out the reservoir simulations using TOUGH2 simulator. The second part of this work is to create a database of thermal potential and time-dependant reservoir conditions for low-temperature geothermal reservoirs by studying a number of possible scenarios. Variations in the parameters identified in sensitivity analysis study are used to expand the scope of database. Main results include the thermal potential of reservoir, pressure and temperature profile of the reservoir over its operational life (30 years for this study), the plant capacity and required pumping power. The results of this database will help the supply curves calculations for low-temperature geothermal reservoirs in the United States, which is the long term goal of the work being done by the geothermal research group under Dr. Anderson at

  6. Open System Models of Isotopic Evolution in Earth's Silicate Reservoirs (United States)

    Kumari, S.; Paul, D.; Stracke, A.


    The present-day elemental and isotopic composition of Earth's terrestrial reservoirs can be used as geochemical constraints to study evolution of the crust-mantle system. A flexible open system evolutionary model of the Earth, comprising continental crust (CC), upper depleted mantle (UM) -source of mid-ocean ridge basalts (MORB), and lower mantle (LM) reservoir with an isolated reservoir-source of ocean island basalts (OIB), and incorporating key radioactive isotope systematics (Rb-Sr, Sm-Nd, and U-Th-Pb), is solved numerically at 1 Ma time step for 4.55 Ga, the age of the Earth. The best possible model-derived solution is the one that produces the present-day concentrations as well as isotopic ratios in terrestrial reservoirs, constrained from published data. Various crustal growth scenarios (continuous versus episodic and early versus late) and its effect on the evolution of isotope systematics in the silicate reservoirs have been evaluated. Modeling results suggest that a whole mantle that is compositionally similar to the present-day MORB source is not consistent with observational constraints. However, a heterogeneous mantle model, in which the present-day UM is 60% of the total mantle mass and a lower non-chondritic mantle, reproduces the estimated isotopic ratios and abundances in Earth's silicate reservoirs. Our results shows that mode of crustal growth strongly affects isotopic evolution of silicate Earth; only an exponential crustal growth pattern satisfactorily explains the chemical and isotopic evolution of the crust-mantle system. One notable feature of successful models is an early depletion of incompatible elements (and a rapid decrease in Th/U ratio, κ, in the UM) by the initial 500 Ma, as a result of early formation of continental crust. Assuming a slightly younger age of the Earth (4.45 Ga), our model better satisfies the Pb-isotope systematics in the respective silicate reservoirs, particularly in the UM, and explains the origin of several OIBs

  7. A review of reservoir desiltation

    DEFF Research Database (Denmark)

    Brandt, Anders


    physical geography, hydrology, desilation efficiency, reservoir flushing, density-current venting, sediment slucing, erosion pattern, downstream effects, flow characteristics, sedimentation......physical geography, hydrology, desilation efficiency, reservoir flushing, density-current venting, sediment slucing, erosion pattern, downstream effects, flow characteristics, sedimentation...

  8. Reservoir sedimentation; a literature survey

    NARCIS (Netherlands)

    Sloff, C.J.


    A survey of literature is made on reservoir sedimentation, one of the most threatening processes for world-wide reservoir performance. The sedimentation processes, their impacts, and their controlling factors are assessed from a hydraulic engineering point of view with special emphasis on


    Energy Technology Data Exchange (ETDEWEB)

    Abbas Firoozabadi


    The four chapters that are described in this report cover a variety of subjects that not only give insight into the understanding of multiphase flow in fractured porous media, but they provide also major contribution towards the understanding of flow processes with in-situ phase formation. In the following, a summary of all the chapters will be provided. Chapter I addresses issues related to water injection in water-wet fractured porous media. There are two parts in this chapter. Part I covers extensive set of measurements for water injection in water-wet fractured porous media. Both single matrix block and multiple matrix blocks tests are covered. There are two major findings from these experiments: (1) co-current imbibition can be more efficient than counter-current imbibition due to lower residual oil saturation and higher oil mobility, and (2) tight fractured porous media can be more efficient than a permeable porous media when subjected to water injection. These findings are directly related to the type of tests one can perform in the laboratory and to decide on the fate of water injection in fractured reservoirs. Part II of Chapter I presents modeling of water injection in water-wet fractured media by modifying the Buckley-Leverett Theory. A major element of the new model is the multiplication of the transfer flux by the fractured saturation with a power of 1/2. This simple model can account for both co-current and counter-current imbibition and computationally it is very efficient. It can be orders of magnitude faster than a conventional dual-porosity model. Part II also presents the results of water injection tests in very tight rocks of some 0.01 md permeability. Oil recovery from water imbibition tests from such at tight rock can be as high as 25 percent. Chapter II discusses solution gas-drive for cold production from heavy-oil reservoirs. The impetus for this work is the study of new gas phase formation from in-situ process which can be significantly

  10. Reservoir engineering and hydrogeology

    International Nuclear Information System (INIS)



    Summaries are included which show advances in the following areas: fractured porous media, flow in single fractures or networks of fractures, hydrothermal flow, hydromechanical effects, hydrochemical processes, unsaturated-saturated systems, and multiphase multicomponent flows. The main thrust of these efforts is to understand the movement of mass and energy through rocks. This has involved treating fracture rock masses in which the flow phenomena within both the fractures and the matrix must be investigated. Studies also address the complex coupling between aspects of thermal, hydraulic, and mechanical processes associated with a nuclear waste repository in a fractured rock medium. In all these projects, both numerical modeling and simulation, as well as field studies, were employed. In the theoretical area, a basic understanding of multiphase flow, nonisothermal unsaturated behavior, and new numerical methods have been developed. The field work has involved reservoir testing, data analysis, and case histories at a number of geothermal projects

  11. Chalk as a reservoir

    DEFF Research Database (Denmark)

    Fabricius, Ida Lykke

    basin, so stylolite formation in the chalk is controlled by effective burial stress. The stylolites are zones of calcite dissolution and probably are the source of calcite for porefilling cementation which is typical in water zone chalk and also affect the reservoirs to different extent. The relatively...... 50% calcite, leaving the remaining internal surface to the fine grained silica and clay. The high specific surface of these components causes clay- and silica rich intervals to have high irreducible water saturation. Although chalks typically are found to be water wet, chalk with mixed wettability...... stabilizes chemically by recrystallization. This process requires energy and is promoted by temperature. This recrystallization in principle does not influence porosity, but only specific surface, which decreases during recrystallization, causing permeability to increase. The central North Sea is a warm...

  12. Pacifiers: a microbial reservoir. (United States)

    Comina, Elodie; Marion, Karine; Renaud, François N R; Dore, Jeanne; Bergeron, Emmanuelle; Freney, Jean


    The permanent contact between the nipple part of pacifiers and the oral microflora offers ideal conditions for the development of biofilms. This study assessed the microbial contamination on the surface of 25 used pacifier nipples provided by day-care centers. Nine were made of silicone and 16 were made of latex. The biofilm was quantified using direct staining and microscopic observations followed by scraping and microorganism counting. The presence of a biofilm was confirmed on 80% of the pacifier nipples studied. This biofilm was mature for 36% of them. Latex pacifier nipples were more contaminated than silicone ones. The two main genera isolated were Staphylococcus and Candida. Our results confirm that nipples can be seen as potential reservoirs of infections. However, pacifiers do have some advantages; in particular, the potential protection they afford against sudden infant death syndrome. Strict rules of hygiene and an efficient antibiofilm cleaning protocol should be established to answer the worries of parents concerning the safety of pacifiers.

  13. Occupational dose constraint

    International Nuclear Information System (INIS)

    Heilbron Filho, Paulo Fernando Lavalle; Xavier, Ana Maria


    The revision process of the international radiological protection regulations has resulted in the adoption of new concepts, such as practice, intervention, avoidable and restriction of dose (dose constraint). The latter deserving of special mention since it may involve reducing a priori of the dose limits established both for the public and to individuals occupationally exposed, values that can be further reduced, depending on the application of the principle of optimization. This article aims to present, with clarity, from the criteria adopted to define dose constraint values to the public, a methodology to establish the dose constraint values for occupationally exposed individuals, as well as an example of the application of this methodology to the practice of industrial radiography

  14. Psychological constraints on egalitarianism

    DEFF Research Database (Denmark)

    Kasperbauer, Tyler Joshua


    Debates over egalitarianism for the most part are not concerned with constraints on achieving an egalitarian society, beyond discussions of the deficiencies of egalitarian theory itself. This paper looks beyond objections to egalitarianism as such and investigates the relevant psychological...... processes motivating people to resist various aspects of egalitarianism. I argue for two theses, one normative and one descriptive. The normative thesis holds that egalitarians must take psychological constraints into account when constructing egalitarian ideals. I draw from non-ideal theories in political...... philosophy, which aim to construct moral goals with current social and political constraints in mind, to argue that human psychology must be part of a non-ideal theory of egalitarianism. The descriptive thesis holds that the most fundamental psychological challenge to egalitarian ideals comes from what...

  15. Bathymetry and capacity of Blackfoot Reservoir, Caribou County, Idaho, 2011 (United States)

    Wood, Molly S.; Skinner, Kenneth D.; Fosness, Ryan L.


    The U.S. Geological Survey (USGS), in cooperation with the Shoshone-Bannock Tribes, surveyed the bathymetry and selected above-water sections of Blackfoot Reservoir, Caribou County, Idaho, in 2011. Reservoir operators manage releases from Government Dam on Blackfoot Reservoir based on a stage-capacity relation developed about the time of dam construction in the early 1900s. Reservoir operation directly affects the amount of water that is available for irrigation of agricultural land on the Fort Hall Indian Reservation and surrounding areas. The USGS surveyed the below-water sections of the reservoir using a multibeam echosounder and real-time kinematic global positioning system (RTK-GPS) equipment at full reservoir pool in June 2011, covering elevations from 6,090 to 6,119 feet (ft) above the North American Vertical Datum of 1988 (NAVD 88). The USGS used data from a light detection and ranging (LiDAR) survey performed in 2000 to map reservoir bathymetry from 6,116 to 6,124 ft NAVD 88, which were mostly in depths too shallow to measure with the multibeam echosounder, and most of the above-water section of the reservoir (above 6,124 ft NAVD 88). Selected points and bank erosional features were surveyed by the USGS using RTK-GPS and a total station at low reservoir pool in September 2011 to supplement and verify the LiDAR data. The stage-capacity relation was revised and presented in a tabular format. The datasets show a 2.0-percent decrease in capacity from the original survey, due to sedimentation or differences in accuracy between surveys. A 1.3-percent error also was detected in the previously used capacity table and measured water-level elevation because of questionable reference elevation at monitoring stations near Government Dam. Reservoir capacity in 2011 at design maximum pool of 6,124 ft above NAVD 88 was 333,500 acre-ft.

  16. Advances in photonic reservoir computing

    Directory of Open Access Journals (Sweden)

    Van der Sande Guy


    Full Text Available We review a novel paradigm that has emerged in analogue neuromorphic optical computing. The goal is to implement a reservoir computer in optics, where information is encoded in the intensity and phase of the optical field. Reservoir computing is a bio-inspired approach especially suited for processing time-dependent information. The reservoir’s complex and high-dimensional transient response to the input signal is capable of universal computation. The reservoir does not need to be trained, which makes it very well suited for optics. As such, much of the promise of photonic reservoirs lies in their minimal hardware requirements, a tremendous advantage over other hardware-intensive neural network models. We review the two main approaches to optical reservoir computing: networks implemented with multiple discrete optical nodes and the continuous system of a single nonlinear device coupled to delayed feedback.

  17. Decay of HIV DNA in the Reservoir and the Impact of Short Treatment Interruption in Kenyan Infants. (United States)

    Pankau, Mark D; Wamalwa, Dalton; Benki-Nugent, Sarah; Tapia, Kenneth; Ngugi, Evelyn; Langat, Agnes; Otieno, Vincent; Moraa, Helen; Maleche-Obimbo, Elizabeth; Overbaugh, Julie; John-Stewart, Grace C; Lehman, Dara A


    We compared change in HIV reservoir DNA following continued antiretroviral therapy (ART) vs short treatment interruption (TI) in early ART-treated Kenyan infants. While HIV DNA in the reservoir decayed with continued ART, HIV DNA levels were similar to pre-TI HIV DNA reservoir levels in most children after short TI.

  18. Gravity observations for hydrocarbon reservoir monitoring

    NARCIS (Netherlands)

    Glegola, M.A.


    In this thesis the added value of gravity observations for hydrocarbon reservoir monitoring and characterization is investigated. Reservoir processes and reservoir types most suitable for gravimetric monitoring are identified. Major noise sources affecting time-lapse gravimetry are analyzed. The

  19. [The Nature and Issues of Drug Addiction Treatment under Constraint]. (United States)

    Quirion, Bastien


    This article is exploring different forms of constraint that are exerted in the field of drug addiction treatment. The objective of this article is to establish benchmarks and to stimulate reflection about the ethical and clinical implications of those constraints in the field of drug addiction treatment. This article is presenting a critical review of different forms of constraint that can be exerted in Canada in regard to the treatment of drug addiction. In the first section of the article, a definition of therapeutic intervention is proposed, that includes the dimension of power, which justifies the importance of considering the coercive aspects of treatment. The second section, which represents the core section of the paper, is devoted to the presentation of different levels of constraint that can be distinguished in regard to drug addicts who are under treatment. Three levels of constraint are exposed: judicial constraint, institutional constraint and relational constraint. The coercive aspect of treatment can then be recognized as a combination of all tree levels of constraint. Judicial constraint refers to any form of constraint in which the court or the judge is imposing or recommending treatment. This particular level of constraint can take different forms, such as therapeutic remands, conditions of a probation order, conditions of a conditional sentence of imprisonment, and coercive treatment such as the ones provided through drug courts. Institutional constraint refers to any form of constraint exerted within any institutional setting, such as correctional facilities and programs offered in community. Correctional facilities being limited by their own specific mission, it might have a major impact on the way the objectives of treatment are defined. Those limitations can then be considered as a form of constraint, in which drug users don't have much space to express their personal needs. Finally, relational constraint refers to any form of constraint in

  20. Nonlinear Filtering Effects of Reservoirs on Flood Frequency Curves at the Regional Scale: RESERVOIRS FILTER FLOOD FREQUENCY CURVES

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wei; Li, Hong-Yi; Leung, Lai-Yung; Yigzaw, Wondmagegn Y.; Zhao, Jianshi; Lu, Hui; Deng, Zhiqun; Demissie, Yonas; Bloschl, Gunter


    Anthropogenic activities, e.g., reservoir operation, may alter the characteristics of Flood Frequency Curve (FFC) and challenge the basic assumption of stationarity used in flood frequency analysis. This paper presents a combined data-modeling analysis of the nonlinear filtering effects of reservoirs on the FFCs over the contiguous United States. A dimensionless Reservoir Impact Index (RII), defined as the total upstream reservoir storage capacity normalized by the annual streamflow volume, is used to quantify reservoir regulation effects. Analyses are performed for 388 river stations with an average record length of 50 years. The first two moments of the FFC, mean annual maximum flood (MAF) and coefficient of variations (CV), are calculated for the pre- and post-dam periods and compared to elucidate the reservoir regulation effects as a function of RII. It is found that MAF generally decreases with increasing RII but stabilizes when RII exceeds a threshold value, and CV increases with RII until a threshold value beyond which CV decreases with RII. The processes underlying the nonlinear threshold behavior of MAF and CV are investigated using three reservoir models with different levels of complexity. All models capture the non-linear relationships of MAF and CV with RII, suggesting that the basic flood control function of reservoirs is key to the non-linear relationships. The relative roles of reservoir storage capacity, operation objectives, available storage prior to a flood event, and reservoir inflow pattern are systematically investigated. Our findings may help improve flood-risk assessment and mitigation in regulated river systems at the regional scale.

  1. Constraint-based scheduling applying constraint programming to scheduling problems

    CERN Document Server

    Baptiste, Philippe; Nuijten, Wim


    Constraint Programming is a problem-solving paradigm that establishes a clear distinction between two pivotal aspects of a problem: (1) a precise definition of the constraints that define the problem to be solved and (2) the algorithms and heuristics enabling the selection of decisions to solve the problem. It is because of these capabilities that Constraint Programming is increasingly being employed as a problem-solving tool to solve scheduling problems. Hence the development of Constraint-Based Scheduling as a field of study. The aim of this book is to provide an overview of the most widely used Constraint-Based Scheduling techniques. Following the principles of Constraint Programming, the book consists of three distinct parts: The first chapter introduces the basic principles of Constraint Programming and provides a model of the constraints that are the most often encountered in scheduling problems. Chapters 2, 3, 4, and 5 are focused on the propagation of resource constraints, which usually are responsibl...

  2. Analysis of real-time reservoir monitoring : reservoirs, strategies, & modeling.

    Energy Technology Data Exchange (ETDEWEB)

    Mani, Seethambal S.; van Bloemen Waanders, Bart Gustaaf; Cooper, Scott Patrick; Jakaboski, Blake Elaine; Normann, Randy Allen; Jennings, Jim (University of Texas at Austin, Austin, TX); Gilbert, Bob (University of Texas at Austin, Austin, TX); Lake, Larry W. (University of Texas at Austin, Austin, TX); Weiss, Chester Joseph; Lorenz, John Clay; Elbring, Gregory Jay; Wheeler, Mary Fanett (University of Texas at Austin, Austin, TX); Thomas, Sunil G. (University of Texas at Austin, Austin, TX); Rightley, Michael J.; Rodriguez, Adolfo (University of Texas at Austin, Austin, TX); Klie, Hector (University of Texas at Austin, Austin, TX); Banchs, Rafael (University of Texas at Austin, Austin, TX); Nunez, Emilio J. (University of Texas at Austin, Austin, TX); Jablonowski, Chris (University of Texas at Austin, Austin, TX)


    The project objective was to detail better ways to assess and exploit intelligent oil and gas field information through improved modeling, sensor technology, and process control to increase ultimate recovery of domestic hydrocarbons. To meet this objective we investigated the use of permanent downhole sensors systems (Smart Wells) whose data is fed real-time into computational reservoir models that are integrated with optimized production control systems. The project utilized a three-pronged approach (1) a value of information analysis to address the economic advantages, (2) reservoir simulation modeling and control optimization to prove the capability, and (3) evaluation of new generation sensor packaging to survive the borehole environment for long periods of time. The Value of Information (VOI) decision tree method was developed and used to assess the economic advantage of using the proposed technology; the VOI demonstrated the increased subsurface resolution through additional sensor data. Our findings show that the VOI studies are a practical means of ascertaining the value associated with a technology, in this case application of sensors to production. The procedure acknowledges the uncertainty in predictions but nevertheless assigns monetary value to the predictions. The best aspect of the procedure is that it builds consensus within interdisciplinary teams The reservoir simulation and modeling aspect of the project was developed to show the capability of exploiting sensor information both for reservoir characterization and to optimize control of the production system. Our findings indicate history matching is improved as more information is added to the objective function, clearly indicating that sensor information can help in reducing the uncertainty associated with reservoir characterization. Additional findings and approaches used are described in detail within the report. The next generation sensors aspect of the project evaluated sensors and packaging

  3. Well testing in gas hydrate reservoirs


    Kome, Melvin Njumbe


    Reservoir testing and analysis are fundamental tools in understanding reservoir hydraulics and hence forecasting reservoir responses. The quality of the analysis is very dependent on the conceptual model used in investigating the responses under different flowing conditions. The use of reservoir testing in the characterization and derivation of reservoir parameters is widely established, especially in conventional oil and gas reservoirs. However, with depleting conventional reserves, the ...

  4. Constraints and Creativity in NPD - Testing the Impact of 'Late Constraints'

    DEFF Research Database (Denmark)

    Onarheim, Balder; Valgeirsdóttir, Dagný

    The aim of the presented work is to investigate how the timing of project constraints can influence the creativity of the output in New Product Development (NPD) projects. When seeking to produce a creative output, is it beneficial to know all constraints when initiating a project......, or will constraints introduced throughout a project potentially lead to a more creative output? While the relationship between constraints and creativity is fairly well studied, the question of how introducing constraints late in a project can influence creativity is still unanswered. A single factor, two level...... was assessed for creativity using the Consensual Assessment Technique (CAT), and a comparative within-subjects analysis found no significant different between the two conditions. Controlling for task and assessor a small but non-significant effect was found, in favor of the ‘late constraint’ condition. Thus...

  5. Gradient-based methods for production optimization of oil reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Suwartadi, Eka


    Production optimization for water flooding in the secondary phase of oil recovery is the main topic in this thesis. The emphasis has been on numerical optimization algorithms, tested on case examples using simple hypothetical oil reservoirs. Gradientbased optimization, which utilizes adjoint-based gradient computation, is used to solve the optimization problems. The first contribution of this thesis is to address output constraint problems. These kinds of constraints are natural in production optimization. Limiting total water production and water cut at producer wells are examples of such constraints. To maintain the feasibility of an optimization solution, a Lagrangian barrier method is proposed to handle the output constraints. This method incorporates the output constraints into the objective function, thus avoiding additional computations for the constraints gradient (Jacobian) which may be detrimental to the efficiency of the adjoint method. The second contribution is the study of the use of second-order adjoint-gradient information for production optimization. In order to speedup convergence rate in the optimization, one usually uses quasi-Newton approaches such as BFGS and SR1 methods. These methods compute an approximation of the inverse of the Hessian matrix given the first-order gradient from the adjoint method. The methods may not give significant speedup if the Hessian is ill-conditioned. We have developed and implemented the Hessian matrix computation using the adjoint method. Due to high computational cost of the Newton method itself, we instead compute the Hessian-timesvector product which is used in a conjugate gradient algorithm. Finally, the last contribution of this thesis is on surrogate optimization for water flooding in the presence of the output constraints. Two kinds of model order reduction techniques are applied to build surrogate models. These are proper orthogonal decomposition (POD) and the discrete empirical interpolation method (DEIM

  6. Ecosystems emerging. 5: Constraints

    Czech Academy of Sciences Publication Activity Database

    Patten, B. C.; Straškraba, Milan; Jorgensen, S. E.


    Roč. 222, č. 16 (2011), s. 2945-2972 ISSN 0304-3800 Institutional research plan: CEZ:AV0Z50070508 Keywords : constraint * epistemic * ontic Subject RIV: EH - Ecology, Behaviour Impact factor: 2.326, year: 2011

  7. Temporal Concurrent Constraint Programming

    DEFF Research Database (Denmark)

    Valencia, Frank Dan

    Concurrent constraint programming (ccp) is a formalism for concurrency in which agents interact with one another by telling (adding) and asking (reading) information in a shared medium. Temporal ccp extends ccp by allowing agents to be constrained by time conditions. This dissertation studies...

  8. Constraints on Dbar uplifts

    International Nuclear Information System (INIS)

    Alwis, S.P. de


    We discuss constraints on KKLT/KKLMMT and LVS scenarios that use anti-branes to get an uplift to a deSitter vacuum, coming from requiring the validity of an effective field theory description of the physics. We find these are not always satisfied or are hard to satisfy.

  9. Sediment Characteristics of Tennessee Streams and Reservoirs

    National Research Council Canada - National Science Library

    Trimble, Stanley W; Carey, William P


    Suspended-sediment and reservoir sedimentation data have been analyzed to determine sediment yields and transport characteristics of Tennessee streams Data from 31 reservoirs plus suspended-sediment...

  10. Changes to the Bakomi Reservoir

    Directory of Open Access Journals (Sweden)

    Kubinský Daniel


    Full Text Available This article is focused on the analysis and evaluation of the changes of the bottom of the Bakomi reservoir, the total volume of the reservoir, ecosystems, as well as changes in the riparian zone of the Bakomi reservoir (situated in the central Slovakia. Changes of the water component of the reservoir were subject to the deposition by erosion-sedimentation processes, and were identifed on the basis of a comparison of the present relief of the bottom of reservoir obtained from feld measurements (in 2011 with the relief measurements of the bottom obtained from the 1971 historical maps, (i.e. over a period of 40 years. Changes of landscape structures of the riparian zone have been mapped for the time period of 1949–2013; these changes have been identifed with the analysis of ortophotomaps and the feld survey. There has been a signifcant rise of disturbed shores with low herb grassland. Over a period of 40 years, there has been a deposition of 667 m3 of sediments. The results showed that there were no signifcant changes in the local ecosystems of the Bakomi reservoir in comparison to the other reservoirs in the vicinity of Banská Štiavnica.


    Energy Technology Data Exchange (ETDEWEB)

    Lam, P.S.; Morgan, M.J


    The burst test is used to assess the material performance of tritium reservoirs in the surveillance program in which reservoirs have been in service for extended periods of time. A materials system model and finite element procedure were developed under a Savannah River Site Plant-Directed Research and Development (PDRD) program to predict the structural response under a full range of loading and aged material conditions of the reservoir. The results show that the predicted burst pressure and volume ductility are in good agreement with the actual burst test results for the unexposed units. The material tensile properties used in the calculations were obtained from a curved tensile specimen harvested from a companion reservoir by Electric Discharge Machining (EDM). In the absence of exposed and aged material tensile data, literature data were used for demonstrating the methodology in terms of the helium-3 concentration in the metal and the depth of penetration in the reservoir sidewall. It can be shown that the volume ductility decreases significantly with the presence of tritium and its decay product, helium-3, in the metal, as was observed in the laboratory-controlled burst tests. The model and analytical procedure provides a predictive tool for reservoir structural integrity under aging conditions. It is recommended that benchmark tests and analysis for aged materials be performed. The methodology can be augmented to predict performance for reservoir with flaws.

  12. Assesment of bathymetric maps via GIS for water in reservoir

    Directory of Open Access Journals (Sweden)

    Ayhan Ceylan

    Full Text Available In order to adopt measures for storing more water in reservoirs, lakes and ponds; to prevent water pollution, protect water sources and extend the service life of these facilities, it is important for manager (Municipalities, Directorates of the State Hydraulic Works (DSHW, Irrigation Unions etc. to know the current topographic conditions and any changes in the storage capacities of these facilities. This study aimed to identify the updated topographic and bathymetric data required for the efficient management and usage of Altınapa reservoir, changes in surface area and volume of the facility, and to form a Reservoir Information System (RIS. Two digital elevation models, from 2009 and 1984, were used to determine changes in the storage capacity of the reservoir. The calculations indicated that, within this 25-year period, the storage capacity of the reservoir decreased by 12.7% due to sedimentation. A Dam Information System (RIS was developed from a wide range of data sources, including topographic and bathymetric data of the reservoir and its surrounding area, data on specific features such as plant cover, water quality characteristics (Temperature, Dissolved Oxygen (DO, Secchi Disk Depth (SDD and pH, geological structure, average water level, water supplied from springs, evaporation value of the reservoir, and precipitation.

  13. Relative influence of deposition and diagenesis on carbonate reservoir layering

    Energy Technology Data Exchange (ETDEWEB)

    Poli, Emmanuelle [Total E and P, Courbevoie (France); Javaux, Catherine [Total E and P, Pointe Noire (Congo)


    The architecture heterogeneities and petrophysical properties of carbonate reservoirs result from a combination of platform morphology, related depositional environments, relative sea level changes and diagenetic events. The reservoir layering built for static and dynamic modelling purposes should reflect the key heterogeneities (depositional or diagenetic) which govern the fluid flow patterns. The layering needs to be adapted to the goal of the modelling, ranging from full field computations of hydrocarbon volumes, to sector-based fine-scale simulations to test the recovery improvement. This paper illustrates various reservoir layering types, including schemes dominated by depositional architecture, and those more driven by the diagenetic overprint. The examples include carbonate platform reservoirs from different stratigraphic settings (Tertiary, Cretaceous, Jurassic and Permian) and different regions (Europe, Africa and Middle East areas). This review shows how significant stratigraphic surfaces (such as sequence boundaries or maximum flooding) with their associated facies shifts, can be often considered as key markers to constrain the reservoir layering. Conversely, how diagenesis (dolomitization and karst development), resulting in units with particular poroperm characteristics, may significantly overprint the primary reservoir architecture by generating flow units which cross-cut depositional sequences. To demonstrate how diagenetic processes can create reservoir bodies with geometries that cross-cut the depositional fabric, different types of dolomitization and karst development are illustrated. (author)

  14. Putting integrated reservoir characterization into practice - in house training

    Energy Technology Data Exchange (ETDEWEB)

    Wright, F.M. Jr.; Best, D.A.; Clarke, R.T. [Mobile Exploration and Producing Technical Center, Dallas, TX (United States)


    The need for even more efficient reservoir characterization and management has forced a change in the way Mobil Oil provides technical support to its production operations. We`ve learned that to be successful, a good understanding of the reservoir is essential. This includes an understanding of the technical and business significance of reservoir heterogeneities at different stages of field development. A multi-disciplinary understanding of the business of integrated reservoir characterization is essential and to facilitate this understanding, Mobil has developed a highly successful {open_quotes}Reservoir Characterization Field Seminar{close_quotes}. Through specific team based case studies that incorporate outcrop examples and data the program provides participants the opportunity to explore historic and alternative approaches to reservoir description, characterization and management. We explore appropriate levels and timing of data gathering, technology applications, risk assessment and management practices at different stages of field development. The case studies presented throughout the course are a unique element of the program which combine real life and hypothetical problem sets that explore how different technical disciplines interact, the approaches to a problem solving they use, the assumptions and uncertainties contained in their contributions and the impact those conclusions may have on other disciplines involved in the overall reservoir management process. The team building aspect of the course was an added bonus.

  15. Optimized reservoir operation model of regional wind and hydro power integration case study: Zambezi basin and South Africa

    International Nuclear Information System (INIS)

    Gebretsadik, Yohannes; Fant, Charles; Strzepek, Kenneth; Arndt, Channing


    Highlights: • The study introduced reliability assessment method of integrated wind–hydropower operation. • The method identifies optimum target power operations that maximizes the firm generation. • We test the proposed method on interconnected system of reservoirs in Southern Africa region. • Results indicate that higher penetration of wind power can be achieved through the proposed frame work of operation. - Abstract: The present study develops a reliability assessment method of wind resource using optimum reservoir target power operations that maximizes the firm generation of integrated wind and hydropower. A combination of water resources model for a system of reservoirs that implements a demand–priority based linear programing algorithm and a single node power grid system model is implemented on hourly time step. This model was accompanied by a global genetic algorithm solver to determine optimum operation targets for each storage reservoir aiming at maximizing the 90th percentile power generation produced by the integration of wind and hydro over the entire simulation period. This model was applied on the reservoir storages and hydropower system in the Zambezi river basin to test if the storage reservoirs could be efficiently be used to offset wind power intermittence in South Africa subjected to the different physical and policy constraints. Based on the optimized target operation and hourly annual real data for the year 2010, the water resources system and power interconnection system were simulated together to assess the maximum firm generation of power as a result of the new wind and hydro combination target for storage hydropower plants. The result obtained indicates that high regulation of wind and hydro can be achieved as a result of combined operation and showed 45% increase in the level of wind penetration in South Africa’s power system over the reference scenario. The result also indicated a reduced level of coal power utilization and

  16. A reservoir simulation approach for modeling of naturally fractured reservoirs

    Directory of Open Access Journals (Sweden)

    H. Mohammadi


    Full Text Available In this investigation, the Warren and Root model proposed for the simulation of naturally fractured reservoir was improved. A reservoir simulation approach was used to develop a 2D model of a synthetic oil reservoir. Main rock properties of each gridblock were defined for two different types of gridblocks called matrix and fracture gridblocks. These two gridblocks were different in porosity and permeability values which were higher for fracture gridblocks compared to the matrix gridblocks. This model was solved using the implicit finite difference method. Results showed an improvement in the Warren and Root model especially in region 2 of the semilog plot of pressure drop versus time, which indicated a linear transition zone with no inflection point as predicted by other investigators. Effects of fracture spacing, fracture permeability, fracture porosity, matrix permeability and matrix porosity on the behavior of a typical naturally fractured reservoir were also presented.


    Directory of Open Access Journals (Sweden)

    Niculae Iulian TEODORESCU


    Full Text Available The Surduc reservoir was projected to ensure more water when water is scarce and to thus provide especially the city Timisoara, downstream of it with water.The accumulation is placed on the main affluent of the Bega river, Gladna in the upper part of its watercourse.The dam behind which this accumulation was created is of a frontal type made of enrochements with a masque made of armed concrete on the upstream part and protected/sustained by grass on the downstream. The dam is 130m long on its coping and a constructed height of 34 m. It is also endowed with spillway for high water and two bottom outlets formed of two conduits, at the end of which is the microplant. The second part of my paper deals with the hydrometric analysis of the Accumulation Surduc and its impact upon the flow, especially the maximum run-off. This influence is exemplified through the high flood from the 29th of July 1980, the most significant flood recorded in the basin with an apparition probability of 0.002%.


    Directory of Open Access Journals (Sweden)

    Ewa Jachniak


    Full Text Available In this publication the trophy level of Wapienica dam reservoir, based on the composition species of planktonic algae and their biomass, and concentrations of chlorophyll a, was defined. The research was conducted during the vegetative season in 2013 year; the samples were taken from two research points (W1 – the part of river Wapienica inflow to reservoir and W2 – the part of the reservoir dam by using bathometer. The whole biomass of planktonic algae and concentration of chlorophyll a from two research areas were low and it allowed to classify water of this reservoir to oligo-/ mesotrophic. Only in the part of the reservoir dam, in summer season, an increased trophy level was observed (Heinonen 1980. A similar trophic character (oligo-/ mesotrophic of the water reservoir was also indicated by algae species: Achnanthes lanceolata (Bréb. Grun. in Cl. and Grun., Chrysoccoccus minutus (Fritsch Nygaard. For a temporary increase of the trophy level, the diatom Nitzschia acicularis (Kütz. W. Sm. could indicate, because it is a typical species in poorly eutrophic water. The green algae (Pediastrum and Coelastrum, which were observed in summer season could also indicate for a rise of the trophic state, because they are typical for eutrophic water.

  19. An ensemble-based method for constrained reservoir life-cycle optimization

    NARCIS (Netherlands)

    Leeuwenburgh, O.; Egberts, P.J.P.; Chitu, A.G.


    We consider the problem of finding optimal long-term (life-cycle) recovery strategies for hydrocarbon reservoirs by use of simulation models. In such problems the presence of operating constraints, such as for example a maximum rate limit for a group of wells, may strongly influence the range of

  20. A constraint algorithm for singular Lagrangians subjected to nonholonomic constraints

    Energy Technology Data Exchange (ETDEWEB)

    de Leon, M. [Instituto de Matematicas y Fisica Fundamental, Consejo Superior de Investigaciones Cientificas, Serrano 123, 28006 Madrid (Spain); de Diego, D.M. [Departamento de Economia Aplicada Cuantitativa, Facultad de Ciencias Economicas y Empresariales, UNED, 28040 Madrid (Spain)


    We construct a constraint algorithm for singular Lagrangian systems subjected to nonholonomic constraints which generalizes that of Dirac for constrained Hamiltonian systems. {copyright} {ital 1997 American Institute of Physics.}

  1. A parallel adaptive finite difference algorithm for petroleum reservoir simulation

    Energy Technology Data Exchange (ETDEWEB)

    Hoang, Hai Minh


    Adaptive finite differential for problems arising in simulation of flow in porous medium applications are considered. Such methods have been proven useful for overcoming limitations of computational resources and improving the resolution of the numerical solutions to a wide range of problems. By local refinement of the computational mesh where it is needed to improve the accuracy of solutions, yields better solution resolution representing more efficient use of computational resources than is possible with traditional fixed-grid approaches. In this thesis, we propose a parallel adaptive cell-centered finite difference (PAFD) method for black-oil reservoir simulation models. This is an extension of the adaptive mesh refinement (AMR) methodology first developed by Berger and Oliger (1984) for the hyperbolic problem. Our algorithm is fully adaptive in time and space through the use of subcycling, in which finer grids are advanced at smaller time steps than the coarser ones. When coarse and fine grids reach the same advanced time level, they are synchronized to ensure that the global solution is conservative and satisfy the divergence constraint across all levels of refinement. The material in this thesis is subdivided in to three overall parts. First we explain the methodology and intricacies of AFD scheme. Then we extend a finite differential cell-centered approximation discretization to a multilevel hierarchy of refined grids, and finally we are employing the algorithm on parallel computer. The results in this work show that the approach presented is robust, and stable, thus demonstrating the increased solution accuracy due to local refinement and reduced computing resource consumption. (Author)

  2. University Course Timetabling using Constraint Programming

    Directory of Open Access Journals (Sweden)

    Hadi Shahmoradi


    Full Text Available University course timetabling problem is a challenging and time-consuming task on the overall structure of timetable in every academic environment. The problem deals with many factors such as the number of lessons, classes, teachers, students and working time, and these are influenced by some hard and soft constraints. The aim of solving this problem is to assign courses and classes to teachers and students, so that the restrictions are held. In this paper, a constraint programming method is proposed to satisfy maximum constraints and expectation, in order to address university timetabling problem. For minimizing the penalty of soft constraints, a cost function is introduced and AHP method is used for calculating its coefficients. The proposed model is tested on department of management, University of Isfahan dataset using OPL on the IBM ILOG CPLEX Optimization Studio platform. A statistical analysis has been conducted and shows the performance of the proposed approach in satisfying all hard constraints and also the satisfying degree of the soft constraints is on maximum desirable level. The running time of the model is less than 20 minutes that is significantly better than the non-automated ones.


    Directory of Open Access Journals (Sweden)

    Joanna Szczykowska


    Full Text Available The study was carried out using water samples from two small retention reservoirs located in the communes: Czarna Białostocka and Turośń Kościelna in Podlaskie Voivodeship. The main tasks of both reservoirs are to improve the water balance by means of regulating the levels and water outflow. Three characteristic measurement and control points were selected on both reservoirs in accordance to the water flow in the longitudinal section. The first and third points were located near the inflow and outflow of water, while the second in the middle of the reservoirs. Samples of water for the study were collected from the surface layer of the shore zone of the reservoirs once a month from March 2015 to February 2017 (water from two hydrological years was analyzed. Water samples were subject to determination of total phosphorus, total nitrogen, and chlorophyll “a” concentrations, as well as turbidity. Contamination of the water reservoirs with biogenic compounds is a common problem and at the same time difficult to eliminate due to the scattered nature of external sources of pollution, especially in the case of agricultural catchments, as well as the inflow of untreated sewage from areas directly adjacent to the reservoirs. Based on achieved results, high values of TSI (TN, TSI (TP, TSI (Chl, and overall TSI, clearly indicate the progressive degradation of water quality in analyzed reservoirs. Appearing water blooms due to the mass development of phytoplankton adversely affect the quality of water in the reservoirs and biochemical processes occurring both in water and bottom sediments, are conditioned by progressive eutrophication.

  4. Evaluation of field development plans using 3-D reservoir modelling

    Energy Technology Data Exchange (ETDEWEB)

    Seifert, D.; Lewis, J.J.M. [Heriot-Watt Univ., Edinburgh (United Kingdom); Newbery, J.D.H. [Conoco, UK Ltd., Aberdeen (United Kingdom)] [and others


    Three-dimensional reservoir modelling has become an accepted tool in reservoir description and is used for various purposes, such as reservoir performance prediction or integration and visualisation of data. In this case study, a small Northern North Sea turbiditic reservoir was to be developed with a line drive strategy utilising a series of horizontal producer and injector pairs, oriented north-south. This development plan was to be evaluated and the expected outcome of the wells was to be assessed and risked. Detailed analyses of core, well log and analogue data has led to the development of two geological {open_quotes}end member{close_quotes} scenarios. Both scenarios have been stochastically modelled using the Sequential Indicator Simulation method. The resulting equiprobable realisations have been subjected to detailed statistical well placement optimisation techniques. Based upon bivariate statistical evaluation of more than 1000 numerical well trajectories for each of the two scenarios, it was found that the wells inclinations and lengths had a great impact on the wells success, whereas the azimuth was found to have only a minor impact. After integration of the above results, the actual well paths were redesigned to meet external drilling constraints, resulting in substantial reductions in drilling time and costs.

  5. Understanding the True Stimulated Reservoir Volume in Shale Reservoirs

    KAUST Repository

    Hussain, Maaruf


    Successful exploitation of shale reservoirs largely depends on the effectiveness of hydraulic fracturing stimulation program. Favorable results have been attributed to intersection and reactivation of pre-existing fractures by hydraulically-induced fractures that connect the wellbore to a larger fracture surface area within the reservoir rock volume. Thus, accurate estimation of the stimulated reservoir volume (SRV) becomes critical for the reservoir performance simulation and production analysis. Micro-seismic events (MS) have been commonly used as a proxy to map out the SRV geometry, which could be erroneous because not all MS events are related to hydraulic fracture propagation. The case studies discussed here utilized a fully 3-D simulation approach to estimate the SRV. The simulation approach presented in this paper takes into account the real-time changes in the reservoir\\'s geomechanics as a function of fluid pressures. It is consisted of four separate coupled modules: geomechanics, hydrodynamics, a geomechanical joint model for interfacial resolution, and an adaptive re-meshing. Reservoir stress condition, rock mechanical properties, and injected fluid pressure dictate how fracture elements could open or slide. Critical stress intensity factor was used as a fracture criterion governing the generation of new fractures or propagation of existing fractures and their directions. Our simulations were run on a Cray XC-40 HPC system. The studies outcomes proved the approach of using MS data as a proxy for SRV to be significantly flawed. Many of the observed stimulated natural fractures are stress related and very few that are closer to the injection field are connected. The situation is worsened in a highly laminated shale reservoir as the hydraulic fracture propagation is significantly hampered. High contrast in the in-situ stresses related strike-slip developed thereby shortens the extent of SRV. However, far field nature fractures that were not connected to

  6. Chickamauga reservoir embayment study - 1990

    Energy Technology Data Exchange (ETDEWEB)

    Meinert, D.L.; Butkus, S.R.; McDonough, T.A.


    The objectives of this report are three-fold: (1) assess physical, chemical, and biological conditions in the major embayments of Chickamauga Reservoir; (2) compare water quality and biological conditions of embayments with main river locations; and (3) identify any water quality concerns in the study embayments that may warrant further investigation and/or management actions. Embayments are important areas of reservoirs to be considered when assessments are made to support water quality management plans. In general, embayments, because of their smaller size (water surface areas usually less than 1000 acres), shallower morphometry (average depth usually less than 10 feet), and longer detention times (frequently a month or more), exhibit more extreme responses to pollutant loadings and changes in land use than the main river region of the reservoir. Consequently, embayments are often at greater risk of water quality impairments (e.g. nutrient enrichment, filling and siltation, excessive growths of aquatic plants, algal blooms, low dissolved oxygen concentrations, bacteriological contamination, etc.). Much of the secondary beneficial use of reservoirs occurs in embayments (viz. marinas, recreation areas, parks and beaches, residential development, etc.). Typically embayments comprise less than 20 percent of the surface area of a reservoir, but they often receive 50 percent or more of the water-oriented recreational use of the reservoir. This intensive recreational use creates a potential for adverse use impacts if poor water quality and aquatic conditions exist in an embayment.


    Directory of Open Access Journals (Sweden)

    A. S. Amar


    Full Text Available The construction of dams and reservoirs in a river can give significant impacts on its flow of water and sediment, and can cause long-term morphological changes on the river. Reservoir sedimentation can reduce a reservoir’s effective flood control volume, and in some severe cases can cause overtopping during floods. Sediment deposition against a dam can reduce its stability, and affect the operation of low-level outlet works, gates, and valves. The abrasive action of sediment particles can roughen the surface of release facilities and can cause cavitations and vibration. Sedimentation can also affect a reservoir’s water quality, and reduce its flood control, water supply, hydropower, and recreation benefits. Consequently, taking sedimentation into consideration not only in the planning and design, but also in the operation and maintenance of a dam and reservoir is important. Keywords: Erosion rate, reservoir deposit, shear stress.

  8. Identification of genetic polymorphism in Mystus cavasius (Hamilton-Buchanan, 1822 from Gandhisagar reservoir and Bansagar reservoir, Madhya Pradesh, India

    Directory of Open Access Journals (Sweden)

    R.K. Garg


    Full Text Available Genetic relatedness was estimated among 30 genotypes of two populations of Mystus cavasius i.e., Gandhisagar reservoir (n = 15 and Bansagar reservoir (n = 15 using 5 random amplified polymorphic DNA (RAPD-PCR markers. Ten primers were primarily scored of which, 05 primers showed polymorphism and these were selected for polymerase chain reaction (PCR to be used in the final molecular analyses. 64 scorable loci were generated in genotypes from Gandhisagar reservoir of which 62 loci (70.45% were polymorphic; whereas, 108 loci were obtained in genotypes from Bansagar reservoir out of which 87 (98.86% were polymorphic. RAPD analysis showed that the Bansagar reservoir population had higher genetic polymorphism than the Gandhisagar reservoir population. Analysis of Molecular Variance (AMOVA indicated low genetic diversity (Hpop = 0.2017 ± 0.1836; I = 0.312 ± 0.2599 and relative genetic differentiation among the populations (Gst = 0.2052 and restricted gene flow (Nm = 1.9369. The phylogenetic tree constructed by un-weighted pair-group method of analysis (UPGMA showed that all genotypes formed two major clusters representing their respective geographical locations i.e., Gandhisagar reservoir population and Bansagar reservoir population. Present investigation elucidates effectiveness of balancing approaches to make polymorphism as descriptive and determined for optimum genetic amelioration and successful conservation of its genotypic variability. This study also showed high levels of morphometric and genetic variation in Bansagar reservoir population indicated dynamic evolution as revealed by genetic variations in genotypes.

  9. The NCL natural constraint language

    CERN Document Server

    Zhou, Jianyang


    This book presents the Natural Constraint Language (NCL) language, a description language in conventional mathematical logic for modeling and solving constraint satisfaction problems. It uses illustrations and tutorials to detail NCL and its applications.

  10. Carbonate reservoir characterization with lithofacies clustering and porosity prediction

    International Nuclear Information System (INIS)

    Al Moqbel, Abdulrahman; Wang, Yanghua


    One of the objectives in reservoir characterization is to quantitatively or semi-quantitatively map the spatial distribution of its heterogeneity and related properties. With the availability of 3D seismic data, artificial neural networks are capable of discovering the nonlinear relationship between seismic attributes and reservoir parameters. For a target carbonate reservoir, we adopt a two-stage approach to conduct characterization. First, we use an unsupervised neural network, the self-organizing map method, to classify the reservoir lithofacies. Then we apply a supervised neural network, the back-propagation algorithm, to quantitatively predict the porosity of the carbonate reservoir. Based on porosity maps at different time levels, we interpret the target reservoir vertically related to three depositional phases corresponding to, respectively, a lowstand system tract before sea water immersion, a highstand system tract when water covers organic deposits and a transition zone for the sea level falling. The highstand system is the most prospective zone, given the organic content deposited during this stage. The transition zone is also another prospective feature in the carbonate depositional system due to local build-ups

  11. Generation of hybrid meshes for the simulation of petroleum reservoirs; Generation de maillages hybrides pour la simulation de reservoirs petroliers

    Energy Technology Data Exchange (ETDEWEB)

    Balaven-Clermidy, S.


    Oil reservoir simulations study multiphase flows in porous media. These flows are described and evaluated through numerical schemes on a discretization of the reservoir domain. In this thesis, we were interested in this spatial discretization and a new kind of hybrid mesh has been proposed where the radial nature of flows in the vicinity of wells is directly taken into account in the geometry. Our modular approach described wells and their drainage area through radial circular meshes. These well meshes are inserted in a structured reservoir mesh (a Corner Point Geometry mesh) made up with hexahedral cells. Finally, in order to generate a global conforming mesh, proper connections are realized between the different kinds of meshes through unstructured transition ones. To compute these transition meshes that we want acceptable in terms of finite volume methods, an automatic method based on power diagrams has been developed. Our approach can deal with a homogeneous anisotropic medium and allows the user to insert vertical or horizontal wells as well as secondary faults in the reservoir mesh. Our work has been implemented, tested and validated in 2D and 2D1/2. It can also be extended in 3D when the geometrical constraints are simplicial ones: points, segments and triangles. (author)

  12. Petroleum reservoir data for testing simulation models

    Energy Technology Data Exchange (ETDEWEB)

    Lloyd, J.M.; Harrison, W.


    This report consists of reservoir pressure and production data for 25 petroleum reservoirs. Included are 5 data sets for single-phase (liquid) reservoirs, 1 data set for a single-phase (liquid) reservoir with pressure maintenance, 13 data sets for two-phase (liquid/gas) reservoirs and 6 for two-phase reservoirs with pressure maintenance. Also given are ancillary data for each reservoir that could be of value in the development and validation of simulation models. A bibliography is included that lists the publications from which the data were obtained.

  13. Advancing reservoir operation description in physically based hydrological models (United States)

    Anghileri, Daniela; Giudici, Federico; Castelletti, Andrea; Burlando, Paolo


    Last decades have seen significant advances in our capacity of characterizing and reproducing hydrological processes within physically based models. Yet, when the human component is considered (e.g. reservoirs, water distribution systems), the associated decisions are generally modeled with very simplistic rules, which might underperform in reproducing the actual operators' behaviour on a daily or sub-daily basis. For example, reservoir operations are usually described by a target-level rule curve, which represents the level that the reservoir should track during normal operating conditions. The associated release decision is determined by the current state of the reservoir relative to the rule curve. This modeling approach can reasonably reproduce the seasonal water volume shift due to reservoir operation. Still, it cannot capture more complex decision making processes in response, e.g., to the fluctuations of energy prices and demands, the temporal unavailability of power plants or varying amount of snow accumulated in the basin. In this work, we link a physically explicit hydrological model with detailed hydropower behavioural models describing the decision making process by the dam operator. In particular, we consider two categories of behavioural models: explicit or rule-based behavioural models, where reservoir operating rules are empirically inferred from observational data, and implicit or optimization based behavioural models, where, following a normative economic approach, the decision maker is represented as a rational agent maximising a utility function. We compare these two alternate modelling approaches on the real-world water system of Lake Como catchment in the Italian Alps. The water system is characterized by the presence of 18 artificial hydropower reservoirs generating almost 13% of the Italian hydropower production. Results show to which extent the hydrological regime in the catchment is affected by different behavioural models and reservoir

  14. Plankton diversity and limnological characterization in two shallow tropical urban reservoirs of Pernambuco State, Brazil. (United States)

    Almeida, Viviane L S; Melão, Maria da Graça G; Moura, Ariadne N


    Plankton diversity, physical and chemical variables and chlorophyll a were analyzed in two shallow urban reservoirs with different trophic degrees on Pernambuco State, northeastern Brazil. High eutrophication levels were observed in Apipucos reservoir, while Prata reservoir was considered oligotrophic. Values reported for physical and chemical variables and chlorophyll a differed among the studied ecosystems. Richness and plankton diversity were higher in Apipucos reservoir especially for phytoplankton. The presence of potential toxic Cyanophyceae in both reservoirs reflects a problem mainly to Prata reservoir, which is used for public water supply. Differences were observed for some variables among sites of study in Apipucos reservoir, while the differences among strata were negligible in both reservoirs, reflecting the water column mixing by wind action. Rainfall regulated the temporal dynamics for the analyzed variables, with significant seasonal differences, mainly for the major of limnological variables in Apipucos reservoir. Plankton diversity was higher in Apipucos reservoir, especially to phytoplankton, showing that eutrophication and pollution can favor plankton diversity in tropical urban shallow reservoirs.

  15. Parallel Handling of Integrity Constraints

    NARCIS (Netherlands)

    Grefen, P.W.P.J.; Flokstra, Jan; Apers, Peter M.G.


    Integrity constraints form an important part of a data model. Therefore, a complete integrity constraint handling subsystem is considered an important part of any modern DBMS. In implementing an integrity constraint handling subsystem, there are two major problem areas: providing enough

  16. Permeability restoration in underground disposal reservoirs

    International Nuclear Information System (INIS)

    Grubbs, D.M.; Haynes, C.D.; Whittle, G.P.


    The aim of the research performed was to explore methods of permeability restoration in underground disposal reservoirs that may improve the receptive capacity of a well to a level that will allow continued use of the disposal zone without resorting to elevated injection pressures. The laboratory investigation employed a simulated open-hole completion in a disposal well wherein the entire formation face is exposed to the well bore. Cylindrical core samples from representative reservoir rocks through which a central vertical opening or borehole had been drilled were injected with a liquid waste obtained from a chemical manufacturing plant. This particular waste material was found to have a moderate plugging effect when injected into samples of reservoir rocks in a prior study. A review was made of the chemical considerations that might account for the reduction of permeability in waste injection. Purpose of this study was to ascertain the conditions under which the precipitation of certain compounds might occur in the injection of the particular waste liquid employed. A summary of chemical calculations is contained in Appendix B. The data may be useful in the treatment of wastes prior to injection and in the design of restoration procedures where analyses of waste liquids and interstitial materials are available. The results of permeability restoration tests were analyzed mathematically by curve-fitting techniques performed by a digital computer. A summary of the analyses is set forth in the discussion of test results and examples of computer printouts are included in Appendix A

  17. Gravity observations for hydrocarbon reservoir monitoring


    Glegola, M.A.


    In this thesis the added value of gravity observations for hydrocarbon reservoir monitoring and characterization is investigated. Reservoir processes and reservoir types most suitable for gravimetric monitoring are identified. Major noise sources affecting time-lapse gravimetry are analyzed. The added value of gravity data for reservoir monitoring and characterization is analyzed within closed-loop reservoir management concept. Synthetic 2D and 3D numerical experiments are performed where var...

  18. Application of magnetic method to assess the extent of high temperature geothermal reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Soengkono, S.; Hochstein, M.P.


    The extent of thermally altered rocks in high temperature geothermal reservoirs hosted by young volcanic rocks can be assessed from magnetic surveys. Magnetic anomalies associated with many geothermal field in New Zealand and Indonesia can be interpreted in terms of thick (up to 1 km) demagnetized reservoir rocks. Demagnetization of these rocks has been confirmed by core studies and is caused by hydrothermal alteration produced from fluid/rock interactions. Models of the demagnetized Wairakei (NZ) and Kamojang (Indonesia) reservoirs are presented which include the productive areas. Magnetic surveys give fast and economical investigations of high temperature prospects if measurements are made from the air. The magnetic interpretation models can provide important constraints for reservoir models. Magnetic ground surveys can also be used to assess the extent of concealed near surface alteration which can be used in site selection of engineering structures.

  19. Limno-reservoirs as a new landscape, environmental and touristic resource: Pareja Limno-reservoir as a case of study (Guadalajara, Spain) (United States)

    Díaz-Carrión, I.; Sastre-Merlín, A.; Martínez-Pérez, S.; Molina-Navarro, E.; Bienes-Allas, R.


    A limno-reservoir is a hydrologic infrastructure with the main goal of generating a body of water with a constant level in the riverine zone of a reservoir, building a dam that makes de limno-reservoir independent from the main body of water. This dam can be built in the main river supplying the reservoir or any tributary as well flowing into it. Despite its novel conception and design, around a dozen are already operative in some Spanish reservoirs. This infrastructure allows the new water body to be independent of the main reservoir management, so the water level stability is its main distinctive characteristic. It leads to the development of environmental, sports and cultural initiatives; which may be included in a touristic exploitation in a wide sense. An opinion poll was designed in 2009 to be carried out the Pareja Limno-reservoir (Entrepeñas reservoir area, Tajo River Basin, central Spain). The results showed that for both, Pareja inhabitants and occasional visitors, the limno-reservoir has become an important touristic resource, mainly demanded during summer season. The performance of leisure activities (especially swimming) are being the main brand of this novel hydraulic and environmental infrastructure, playing a role as corrective and/or compensatory action which is needed to apply in order to mitigate the environmental impacts of the large hydraulic constructions.

  20. Optimization In Searching Daily Rule Curve At Mosul Regulating Reservoir, North Iraq Using Genetic Algorithms

    Directory of Open Access Journals (Sweden)

    Thair M. Al-Taiee


    Full Text Available To obtain optimal operating rules for storage reservoirs, large numbers of simulation and optimization models have been developed over the past several decades, which vary significantly in their mechanisms and applications. Rule curves are guidelines for long term reservoir operation. An efficient technique is required to find the optimal rule curves that can mitigate water shortage in long term operation. The investigation of developed Genetic Algorithm (GA technique, which is an optimization approach base on the mechanics of natural selection, derived from the theory of natural evolution, was carried out to through the application to predict the daily rule curve of  Mosul regulating reservoir in Iraq.  Record daily inflows, outflow, water level in the reservoir for 19 year (1986-1990 and (1994-2007 were used in the developed model for assessing the optimal reservoir operation. The objective function is set to minimize the annual sum of squared deviation from the desired downstream release and desired storage volume in the reservoir. The decision variables are releases, storage volume, water level and outlet (demand from the reservoir. The results of the GA model gave a good agreement during the comparison with the actual rule curve and the designed rating curve of the reservoir. The simulated result shows that GA-derived policies are promising and competitive and can be effectively used for daily reservoir operation in addition to the rational monthly operation and predicting also rating curve of reservoirs.

  1. Methane emissions from northern Amazon savanna wetlands and Balbina Reservoir (United States)

    Kemenes, A.; Belger, L.; Forsberg, B.; Melack, J. M.


    To improve estimates of methane emission for the Amazon basin requires information from aquatic environments not represented in the central basin near the Solimoes River, where most of the current data were obtained. We have combined intensive, year-long measurements of methane emission and water levels made in interfluvial wetlands located in the upper Negro basin with calculations of inundation based on a time series of Radarsat synthetic aperature radar images. These grass-dominated savannas emitted methane at an average rate of 18 mg C per m squared per day, a low rate compared to the habitats with floating grasses the occur in the Solimoes floodplains. Reservoirs constructed in the Amazon typically flood forested landscapes and lead to conditions conducive for methane production. The methane is released to the atmosphere from the reservoir and as the water exits the turbines and from the downstream river. Balbina Reservoir near Manaus covers about 2400 km squared along the Uatuma River. Annual averages of measurements of methane emission from the various habitats in the reservoir range from 23 to 64 mg C per m squared per day. Total annual emission from the reservoir is about 58 Gg C. In addition, about 39 Gg C per year are released below the dam, about 50 percent of which is released as the water passes through the turbines. On an annual areal basis, Balbina Reservoir emits 40 Mg C km squared, in contrast to 30 Mg km squared for the Solimoes mainstem floodplain

  2. Constraints on hadronically decaying dark matter

    International Nuclear Information System (INIS)

    Garny, Mathias; Ibarra, Alejandro; Tran, David; Minnesota Univ., Minneapolis, MN


    We present general constraints on dark matter stability in hadronic decay channels derived from measurements of cosmic-ray antiprotons.We analyze various hadronic decay modes in a model-independent manner by examining the lowest-order decays allowed by gauge and Lorentz invariance for scalar and fermionic dark matter particles and present the corresponding lower bounds on the partial decay lifetimes in those channels. We also investigate the complementarity between hadronic and gamma-ray constraints derived from searches for monochromatic lines in the sky, which can be produced at the quantum level if the dark matter decays into quark-antiquark pairs at leading order.

  3. Fish habitat degradation in U.S. reservoirs (United States)

    Miranda, Leandro E.; Spickard, M.; Dunn, T.; Webb, K.M.; Aycock, J.N.; Hunt, K.


    As the median age of the thousands of large reservoirs (> 200 ha) in the United States tops 50, many are showing various signs of fish habitat degradation. Our goal was to identify major factors degrading fish habitat in reservoirs across the country, and to explore regional degradation patterns. An online survey including 14 metrics was scored on a 0 (no degradation) to 5 (high degradation) point scale by 221 fisheries scientists (92% response rate) to describe degradation in 482 reservoirs randomly distributed throughout the continental United States. The highest scored sources of degradation were lack of aquatic macrophytes (41% of the reservoirs scored as 4–5), lack or loss of woody debris (35% scored 4–5), mistimed water level fluctuations (34% scored 4–5), and sedimentation (31% scored 4–5). Factor analysis identified five primary degradation factors that accounted for most of the variability in the 14 degradation metrics. The factors reflected siltation, structural habitat, eutrophication, water regime, and aquatic plants. Three degradation factors were driven principally by in-reservoir processes, whereas the other two were driven by inputs from the watershed. A comparison across U.S. regions indicated significant geographical differences in degradation relative to the factors emphasized by each region. Reservoirs sometimes have been dismissed as unnatural and disruptive, but they are a product of public policy, a critical feature of landscapes, and they cannot be overlooked if managers are to effectively conserve river systems. Protection and restoration of reservoir habitats may be enhanced with a broader perspective that includes watershed management, in addition to in reservoir activities.

  4. Artisanal fisheries in a Brazilian hypereutrophic reservoir: Barra Bonita reservoir, middle Tietê river

    Directory of Open Access Journals (Sweden)

    JLC. Novaes

    Full Text Available This study examines the qualitative and quantitative aspects of fishery landings at the hypereutrophic Barra Bonita reservoir, Brazil. Data were collected each month (July/2004-June/2006 at three localities and the reported catch, fishing effort and fishing techniques were recorded from 745 landings, comprising a total fish catch of 86,691.9 kg. The most caught species were exotic tilapias, especially the Nile tilapia (Oreochromis niloticus L., which represented 82.5% of the total biomass. The reservoir's fishery productivity was 11.1 kg/ha-1/day-1 with a Catch Per Unit Effort of 62.4 kg/fisher-1/day-1. Five fishing techniques were identified: cast net, gill net, trawl net, beating gill net, and beating gill net + gill net. The analysis of DCA related the active strategies for the tilapia catch, to the passive strategies for the Pimelodus maculatus (Lacepède and Triportheus angulatus catches (Spix & Agassiz, and the mixed strategies for the tilapia, catfish and Prochilodus lineatus (Valenciennes catches. ANCOVA results were significant for all the variables analysed (season, fishing location and fishing technique. The results showed that fishing for "corvina" Plagioscion squamosissimus (Heckel, predominant in the 1990s, had been replaced by fishing focused on the Nile tilapia. This substitution appears to be due to the increasing levels of eutrophication in the reservoir, combined with changes in fishing techniques. The pattern of the fisheries in Barra Bonita Reservoir follow those in other eutrophic Brazilian reservoirs, with catches of the exotic Nile tilapia predominating.

  5. Reservoir structural model updating using the Ensemble Kalman Filter

    Energy Technology Data Exchange (ETDEWEB)

    Seiler, Alexandra


    time, as new measurements become available. Updates in the structural model impact the reservoir grid, and when the grid architecture is modified, all the cell-referenced and grid-region parameters need to be updated as well. The entire reservoir modeling work flow, from structural modeling to flow simulation, needs to be rerun, and thus, automated. Furthermore, a major constraint is that the current EnKF implementation considers a fixed dimension of the state vector, which implies a constant number of active cells in the reservoir grid. The requirements of an automated work flow and a fixed grid architecture leads to the proposed method, where the geometry of the base-case grid, representing the most likely interpretation, is deformed to match the different realizations of the structural model. In this project, grid deformation algorithms for updating the geometry of a corner-point grid have been developed and integrated in the EnKF model-updating work flow. The proposed method for updating the structural-model uncertainties has been applied to synthetic cases and is implemented on real field cases. The result is an updated ensemble of structural models, conditioned to all production data, and with reduced and quantified uncertainty. The updated ensemble of structures provides a more reliable characterization of the reservoir architecture, including the top and bottom horizons and the fault geometry, and a better estimate of the field oil-in-place. (Author)

  6. Reduction Of Constraints For Coupled Operations

    International Nuclear Information System (INIS)

    Raszewski, F.; Edwards, T.


    the High Level Waste (HLW) System Plan. As with the first phase of testing for sludge-only operations, replacement of the homogeneity constraint with the alumina and sum of alkali constraints will ensure acceptable product durability over the compositional region evaluated. Although these study glasses only provide limited data in a large compositional region, the approach and results are consistent with previous studies that challenged the homogeneity constraint for sludge-only operations. That is, minimal benefit is gained by imposing the homogeneity constraint if the other PCCS constraints are satisfied. The normalized boron releases of all of the glasses are well below the Environmental Assessment (EA) glass results, regardless of thermal history. Although one of the glasses had a normalized boron release of approximately 10 g/L and was not predictable, the glass is still considered acceptable. This particular glass has a low Al 2 O 3 concentration, which may have attributed to the anomalous behavior. Given that poor durability has been previously observed in other glasses with low Al 2 O 3 and Fe 2 O 3 concentrations, including the sludge-only reduction of constraints study, further investigations appear to be warranted. Based on the results of this study, it is recommended that the homogeneity constraint (in its entirety with the associated low frit/high frit constraints) be eliminated for coupled operations as defined by Revision 14 of the HLW System Plan with up to 2 wt% TiO 2 . The use of the alumina and sum of alkali constraints should be continued along with the variability study to determine the predictability of the current durability models and/or that the glasses are acceptable with respect to durability. The use of a variability study for each batch is consistent with the glass product control program and it will help to assess new streams or compositional changes. It is also recommended that the influence of alumina and alkali on durability be studied

  7. Searching for genomic constraints

    International Nuclear Information System (INIS)

    Lio', P.; Ruffo, S.


    The authors have analyzed general properties of very long DNA sequences belonging to simple and complex organisms, by using different correlation methods. They have distinguished those base compositional rules that concern the entire genome which they call 'genomic constraints' from the rules that depend on the 'external natural selection' acting on single genes, i. e. protein-centered constraints. They show that G + C content, purine / pyrimidine distributions and biological complexity of the organism are the most important factors which determine base compositional rules and genome complexity. Three main facts are here reported: bacteria with high G + C content have more restrictions on base composition than those with low G + C content; at constant G + C content more complex organisms, ranging from prokaryotes to higher eukaryotes (e.g. human) display an increase of repeats 10-20 nucleotides long, which are also partly responsible for long-range correlations; work selection of length 3 to 10 is stronger in human and in bacteria for two distinct reasons. With respect to previous studies, they have also compared the genomic sequence of the archeon Methanococcus jannaschii with those of bacteria and eukaryotes: it shows sometimes an intermediate statistical behaviour

  8. Design with Nonlinear Constraints

    KAUST Repository

    Tang, Chengcheng


    Most modern industrial and architectural designs need to satisfy the requirements of their targeted performance and respect the limitations of available fabrication technologies. At the same time, they should reflect the artistic considerations and personal taste of the designers, which cannot be simply formulated as optimization goals with single best solutions. This thesis aims at a general, flexible yet e cient computational framework for interactive creation, exploration and discovery of serviceable, constructible, and stylish designs. By formulating nonlinear engineering considerations as linear or quadratic expressions by introducing auxiliary variables, the constrained space could be e ciently accessed by the proposed algorithm Guided Projection, with the guidance of aesthetic formulations. The approach is introduced through applications in different scenarios, its effectiveness is demonstrated by examples that were difficult or even impossible to be computationally designed before. The first application is the design of meshes under both geometric and static constraints, including self-supporting polyhedral meshes that are not height fields. Then, with a formulation bridging mesh based and spline based representations, the application is extended to developable surfaces including origami with curved creases. Finally, general approaches to extend hard constraints and soft energies are discussed, followed by a concluding remark outlooking possible future studies.

  9. Data Driven Constraints for the SVM

    DEFF Research Database (Denmark)

    Darkner, Sune; Clemmensen, Line Katrine Harder


    classifier solution, compared to the SVM i.e. reduces variance and improves classification rates. We present a quantitative measure of the information level contained in the pairing and test the method on simulated as well as a high-dimensional paired data set of ear-canal surfaces.......We propose a generalized data driven constraint for support vector machines exemplified by classification of paired observations in general and specifically on the human ear canal. This is particularly interesting in dynamic cases such as tissue movement or pathologies developing over time....... Assuming that two observations of the same subject in different states span a vector, we hypothesise that such structure of the data contains implicit information which can aid the classification, thus the name data driven constraints. We derive a constraint based on the data which allow for the use...

  10. Application of Integrated Reservoir Management and Reservoir Characterization to Optimize Infill Drilling

    Energy Technology Data Exchange (ETDEWEB)



    Infill drilling if wells on a uniform spacing without regard to reservoir performance and characterization foes not optimize reservoir development because it fails to account for the complex nature of reservoir heterogeneities present in many low permeability reservoirs, and carbonate reservoirs in particular. New and emerging technologies, such as geostatistical modeling, rigorous decline curve analysis, reservoir rock typing, and special core analysis can be used to develop a 3-D simulation model for prediction of infill locations.

  11. Constraints in the Adoption of Eco Friendly Conservation Practices


    L. Murali Krishnan; H. Philip; M. Chinnadurai; V. Ravichandran


    Adoption of Eco Friendly Conservation Practices requires strong attitude and good knowledge level. Further, the adoption of Eco Friendly Conservation Practices has put fourth many constraints. This study was conducted in The Nilgiris district to assess the constraints and suggestions to overcome the constraints in the adoption of Eco Friendly Conservation Practices. Thus, to analyse the constraints Garett ranking method was used (Garett, H.E. et al 1973). The study revealed that the constrain...

  12. Reservoir effects in radiocarbon dating

    International Nuclear Information System (INIS)

    Head, M.J.


    Full text: The radiocarbon dating technique depends essentially on the assumption that atmospheric carbon dioxide containing the cosmogenic radioisotope 14 C enters into a state of equilibrium with all living material (plants and animals) as part of the terrestrial carbon cycle. Terrestrial reservoir effects occur when the atmospheric 14 C signal is diluted by local effects where systems depleted in 14 C mix with systems that are in equilibrium with the atmosphere. Naturally, this can occur with plant material growing close to an active volcano adding very old CO 2 to the atmosphere (the original 14 C has completely decayed). It can also occur in highly industrialised areas where fossil fuel derived CO 2 dilutes the atmospheric signal. A terrestrial reservoir effect can occur in the case of fresh water shells living in rivers or lakes where there is an input of ground water from springs or a raising of the water table. Soluble bicarbonate derived from the dissolution of very old limestone produces a 14 C dilution effect. Land snail shells and stream carbonate depositions (tufas and travertines) can be affected by a similar mechanism. Alternatively, in specific cases, these reservoir effects may not occur. This means that general interpretations assuming quantitative values for these terrestrial effects are not possible. Each microenvironment associated with samples being analysed needs to be evaluated independently. Similarly, the marine environment produces reservoir effects. With respect to marine shells and corals, the water depth at which carbonate growth occurs can significantly affect quantitative 14 C dilution, especially in areas where very old water is uplifted, mixing with top layers of water that undergo significant exchange with atmospheric CO 2 . Hence, generalisations with respect to the marine reservoir effect also pose problems. These can be exacerbated by the mixing of sea water with either terrestrial water in estuaries, or ground water where

  13. Flood risk management for large reservoirs

    International Nuclear Information System (INIS)

    Poupart, M.


    Floods are a major risk for dams: uncontrolled reservoir water level may cause dam overtopping, and then its failure, particularly for fill dams. Poor control of spillway discharges must be taken into consideration too, as it can increase the flood consequences downstream. In both cases, consequences on the public or on properties may be significant. Spillway design to withstand extreme floods is one response to these risks, but must be complemented by strict operating rules: hydrological forecasting, surveillance and periodic equipment controls, operating guides and the training of operators are mandatory too, in order to guarantee safe operations. (author)

  14. Sustainability constraints on UK bioenergy development

    International Nuclear Information System (INIS)

    Thornley, Patricia; Upham, Paul; Tomei, Julia


    Use of bioenergy as a renewable resource is increasing in many parts of the world and can generate significant environmental, economic and social benefits if managed with due regard to sustainability constraints. This work reviews the environmental, social and economic constraints on key feedstocks for UK heat, power and transport fuel. Key sustainability constraints include greenhouse gas savings achieved for different fuels, land availability, air quality impacts and facility siting. Applying those constraints, we estimate that existing technologies would facilitate a sustainability constrained level of medium-term bioenergy/biofuel supply to the UK of 4.9% of total energy demand, broken down into 4.3% of heat demands, 4.3% of electricity, and 5.8% of transport fuel. This suggests that attempts to increase the supply above these levels could have counterproductive sustainability impacts in the absence of compensating technology developments or identification of additional resources. The barriers that currently prevent this level of supply being achieved have been analysed and classified. This suggests that the biggest policy impacts would be in stimulating the market for heat demand in rural areas, supporting feedstock prices in a manner that incentivised efficient use/maximum greenhouse gas savings and targeting investment capital that improves yield and reduces land-take. (author)

  15. Guiding rational reservoir flood operation using penalty-type genetic algorithm (United States)

    Chang, Li-Chiu


    SummaryReal-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. This study proposes a reservoir flood control optimization model with linguistic description of requirements and existing regulations for rational operating decisions. The approach involves formulating reservoir flood operation as an optimization problem and using the genetic algorithm (GA) as a search engine. The optimizing formulation is expressed not only by mathematical forms of objective function and constraints, but also by no analytic expression in terms of parameters. GA is used to search a global optimum of a mixture of mathematical and nonmathematical formulations. Due to the great number of constraints and flood control requirements, it is difficult to reach a solution without violating constraints. To tackle this bottleneck, the proper penalty strategy for each parameter is proposed to guide the GA searching process. The proposed approach is applied to the Shihmen reservoir in North Taiwan for finding the rational release and desired storage as a case study. The hourly historical data sets of 29 typhoon events that have hit the area in last thirty years are investigated bye the proposed method. To demonstrate the effectiveness of the proposed approach, the simplex method was performed. The results demonstrated that a penalty-type genetic algorithm could effectively provide rational hydrographs to reduce flood damage during the flood operation and to increase final storage for future usages.

  16. Constraints to Rural Women Farmers' Involvement in Food ...

    African Journals Online (AJOL)


    Items 1 - 7 ... Majority of women in rural areas in Nigeria are involved in food production. They face a lot of challenges and constraints, which adversely affect their level of food production. Some examples of such constraints are illiteracy, poverty, lack of application of appropriate technology. Anyakoha and. Mbanefo (2002) had ...

  17. Sedimentological and Geomorphological Effects of Reservoir Flushing: The Cachi Reservoir, Costa Rica, 1996

    DEFF Research Database (Denmark)

    Brandt, Anders; Swenning, Joar


    Physical geography, hydrology, geomorphology, sediment transport, erosion, sedimentation, dams, reservoirs......Physical geography, hydrology, geomorphology, sediment transport, erosion, sedimentation, dams, reservoirs...

  18. Application of Integrated Reservoir Management and Reservoir Characterization to Optimize Infill Drilling

    Energy Technology Data Exchange (ETDEWEB)

    P. K. Pande


    Initial drilling of wells on a uniform spacing, without regard to reservoir performance and characterization, must become a process of the past. Such efforts do not optimize reservoir development as they fail to account for the complex nature of reservoir heterogeneities present in many low permeability reservoirs, and carbonate reservoirs in particular. These reservoirs are typically characterized by: o Large, discontinuous pay intervals o Vertical and lateral changes in reservoir properties o Low reservoir energy o High residual oil saturation o Low recovery efficiency

  19. Diversity of larvae of littoral Chironomidae (Diptera: Insecta and their role as bioindicators in urban reservoirs of different trophic levels Diversidade de larvas de Chironomidae (Diptera: Insecta e seu papel como bioindicadores na região litorânea de reservatórios urbanos em diferentes níveis tróficos

    Directory of Open Access Journals (Sweden)

    SS. Morais


    Full Text Available The Chironomidae (Diptera: Insecta have a high species richness, with species adapted to live under widely different environmental conditions. The study of the taxonomic composition of chironomid larvae and the percentage of occurrence of deformities in mouthparts, mainly in the mentum, are used in biomonitoring programmes in order to obtain information on the levels of organic and chemical pollution of aquatic ecosystems. The objective of this study was to evaluate the abundance of chironomid larvae and to quantify the occurrence of mentum deformities in the specimens collected in three urban reservoirs with different trophic levels. The reservoirs are located in the hydrographic basin of the Paraopeba River, an affluent of the São Francisco River basin (Minas Gerais State, southeastern Brazil. The Serra Azul Reservoir is oligotrophic, the Vargem das Flores Reservoir is mesotrophic, and the Ibirité Reservoir is eutrophic. Along the littoral zone of each reservoir, 30 samples were collected during each sampling campaign. Sampling was carried out every three months for one year, with two sampling campaigns during the wet season and two during the dry season in 2008. Physical and chemical parameters measured in the water column included the water depth, Secchi depth, air and water temperature, electrical conductivity, total dissolved solids, redox potential, dissolved oxygen, pH, turbidity, Total-N, Total-P, P-ortho, and chlorophyll-a. The chironomid larvae were identified to the genus level. The structure of the chironomid assemblages was evaluated based on taxonomic richness (24 genera, density, equitability, and diversity. The potential indicator taxa for each reservoir were established through an Indicator Species Analysis. The values for taxonomic richness (20 taxa, equitability (0.737, and Shannon-Wiener diversity (2.215 were highest in the Serra Azul Reservoir. Fissimentum was the indicator taxon in Serra Azul, the oligotrophic reservoir


    Directory of Open Access Journals (Sweden)

    Daniel Constantin DIACONU


    Full Text Available Siriu reservoir, owes it`s creation to the dam built on the river Buzau, in the town which bears the same name. The reservoir has a hydro energetic role, to diminish the maximum flow and to provide water to the localities below. The partial exploitation of the lake, began in 1984; Since that time, the initial bed of the river began to accumulate large quantities of alluvia, reducing the retention capacity of the lake, which had a volume of 125 million m3. The changes produced are determined by many topographic surveys at the bottom of the lake.

  1. Assessing reservoir operations risk under climate change (United States)

    Brekke, Levi D.; Maurer, Edwin P.; Anderson, Jamie D.; Dettinger, Michael D.; Townsley, Edwin S.; Harrison, Alan; Pruitt, Tom


    Risk-based planning offers a robust way to identify strategies that permit adaptive water resources management under climate change. This paper presents a flexible methodology for conducting climate change risk assessments involving reservoir operations. Decision makers can apply this methodology to their systems by selecting future periods and risk metrics relevant to their planning questions and by collectively evaluating system impacts relative to an ensemble of climate projection scenarios (weighted or not). This paper shows multiple applications of this methodology in a case study involving California's Central Valley Project and State Water Project systems. Multiple applications were conducted to show how choices made in conducting the risk assessment, choices known as analytical design decisions, can affect assessed risk. Specifically, risk was reanalyzed for every choice combination of two design decisions: (1) whether to assume climate change will influence flood-control constraints on water supply operations (and how), and (2) whether to weight climate change scenarios (and how). Results show that assessed risk would motivate different planning pathways depending on decision-maker attitudes toward risk (e.g., risk neutral versus risk averse). Results also show that assessed risk at a given risk attitude is sensitive to the analytical design choices listed above, with the choice of whether to adjust flood-control rules under climate change having considerably more influence than the choice on whether to weight climate scenarios.

  2. Assessing reservoir operations risk under climate change (United States)

    Brekke, L.D.; Maurer, E.P.; Anderson, J.D.; Dettinger, M.D.; Townsley, E.S.; Harrison, A.; Pruitt, T.


    Risk-based planning offers a robust way to identify strategies that permit adaptive water resources management under climate change. This paper presents a flexible methodology for conducting climate change risk assessments involving reservoir operations. Decision makers can apply this methodology to their systems by selecting future periods and risk metrics relevant to their planning questions and by collectively evaluating system impacts relative to an ensemble of climate projection scenarios (weighted or not). This paper shows multiple applications of this methodology in a case study involving California's Central Valley Project and State Water Project systems. Multiple applications were conducted to show how choices made in conducting the risk assessment, choices known as analytical design decisions, can affect assessed risk. Specifically, risk was reanalyzed for every choice combination of two design decisions: (1) whether to assume climate change will influence flood-control constraints on water supply operations (and how), and (2) whether to weight climate change scenarios (and how). Results show that assessed risk would motivate different planning pathways depending on decision-maker attitudes toward risk (e.g., risk neutral versus risk averse). Results also show that assessed risk at a given risk attitude is sensitive to the analytical design choices listed above, with the choice of whether to adjust flood-control rules under climate change having considerably more influence than the choice on whether to weight climate scenarios. Copyright 2009 by the American Geophysical Union.

  3. Environmental impact assessments of the Xiaolangdi Reservoir on the most hyperconcentrated laden river, Yellow River, China. (United States)

    Kong, Dongxian; Miao, Chiyuan; Wu, Jingwen; Borthwick, Alistair G L; Duan, Qingyun; Zhang, Xiaoming


    The Yellow River is the most hyperconcentrated sediment-laden river in the world. Throughout recorded history, the Lower Yellow River (LYR) experienced many catastrophic flood and drought events. To regulate the LYR, a reservoir was constructed at Xiaolangdi that became operational in the early 2000s. An annual water-sediment regulation scheme (WSRS) was then implemented, aimed at flood control, sediment reduction, regulated water supply, and power generation. This study examines the eco-environmental and socioenvironmental impacts of Xiaolangdi Reservoir. In retrospect, it is found that the reservoir construction phase incurred huge financial cost and required large-scale human resettlement. Subsequent reservoir operations affected the local geological environment, downstream riverbed erosion, evolution of the Yellow River delta, water quality, and aquatic biodiversity. Lessons from the impact assessment of the Xiaolangdi Reservoir are summarized as follows: (1) The construction of large reservoirs is not merely an engineering challenge but must also be viewed in terms of resource exploitation, environmental protection, and social development; (2) long-term systems for monitoring large reservoirs should be established, and decision makers involved at national policy and planning levels must be prepared to react quickly to the changing impact of large reservoirs; and (3) the key to solving sedimentation in the LYR is not Xiaolangdi Reservoir but instead soil conservation in the middle reaches of the Yellow River basin. Proper assessment of the impacts of large reservoirs will help promote development strategies that enhance the long-term sustainability of dam projects.

  4. Escape of H and D from Mars' Atmosphere and the Evolution of its Crustal Water Reservoirs (United States)

    Hartle, Richard E.; Einaudi, Franco (Technical Monitor)


    The evolution of water on Mars involves preferential escape of hydrogen over deuterium, producing its deuterium rich atmosphere with a D/H ratio 5.2 times that of terrestrial water. In the past decade, several estimates have been made of the magnitudes of current and ancient crustal water reservoirs on Mars that freely exchange with its atmosphere. Some of the differences in the magnitudes of the reservoirs are influenced by differences in the following basic parameters: composition of H, D, H2 and HD at the exobase; thermal history of the atmosphere; escape mechanisms; and the D/H ratio of earlier epochs as inferred from meteorites. The dominant escape mechanism used in the estimates is Jeans escape. However, the Jeans escape flux is enhanced considerably when atmospheric winds and rotation are applied at the exobase . This constraint is of particular importance because the enhancement of the D escape flux can be an order of magnitude greater than the enhancement of the H escape flux. This preferential enhancement of the D escape flux over that of H means that a great deal more H must escape (than in the case without winds and rotation) to attain the same D/H ratio in the today's atmosphere. Another new constraint on reservoir magnitudes comes from the recent interpretation of Martian meteorite data, which suggests that the D/H ratio was 2 times that of terrestrial water at the end of the heavy bombardment period (1). These two constraints together lead to larger current and ancient crustal water reservoirs. Applying Rayleigh fractionation, new estimates of the sizes of the water reservoirs are made using the above constraints along with plausible values for hydrogen and deuterium densities, temperatures, wind speeds and rotation rates at the exobase.

  5. Reservoir Sedimentation Based on Uncertainty Analysis

    Directory of Open Access Journals (Sweden)

    Farhad Imanshoar


    Full Text Available Reservoir sedimentation can result in loss of much needed reservoir storage capacity, reducing the useful life of dams. Thus, sufficient sediment storage capacity should be provided for the reservoir design stage to ensure that sediment accumulation will not impair the functioning of the reservoir during the useful operational-economic life of the project. However, an important issue to consider when estimating reservoir sedimentation and accumulation is the uncertainty involved in reservoir sedimentation. In this paper, the basic factors influencing the density of sediments deposited in reservoirs are discussed, and uncertainties in reservoir sedimentation have been determined using the Delta method. Further, Kenny Reservoir in the White River Basin in northwestern Colorado was selected to determine the density of deposits in the reservoir and the coefficient of variation. The results of this investigation have indicated that by using the Delta method in the case of Kenny Reservoir, the uncertainty regarding accumulated sediment density, expressed by the coefficient of variation for a period of 50 years of reservoir operation, could be reduced to about 10%. Results of the Delta method suggest an applicable approach for dead storage planning via interfacing with uncertainties associated with reservoir sedimentation.

  6. Solving Sudoku with Constraint Programming (United States)

    Crawford, Broderick; Castro, Carlos; Monfroy, Eric

    Constraint Programming (CP) is a powerful paradigm for modeling and solving Complex Combinatorial Problems (generally issued from Decision Making). In this work, we model the known Sudoku puzzle as a Constraint Satisfaction Problems and solve it with CP comparing the performance of different Variable and Value Selection Heuristics in its Enumeration phase. We encourage this kind of benchmark problem because it may suggest new techniques in constraint modeling and solving of complex systems, or aid the understanding of its main advantages and limits.

  7. Data assimilation in reservoir management

    NARCIS (Netherlands)

    Rommelse, J.R.


    The research presented in this thesis aims at improving computer models that allow simulations of water, oil and gas flows in subsurface petroleum reservoirs. This is done by integrating, or assimilating, measurements into physics-bases models. In recent years petroleum technology has developed

  8. Reservoirs in the United States (United States)

    Harbeck, G. Earl


    Man has engaged in the control of flowing water since history began. Among his early recorded efforts were reservoirs for muncipal water-supplies constructed near ancient Jerusalem to store water which was brought there in masonry conduits. 1/  Irrigation was practiced in Egypt as early as 2000 B. C. There the "basin system" was used from ancient times until the 19th century. The land was divided , into basins of approximately 40,000 acres, separated by earthen dikes. 2/  Flood waters of the Nile generally inundated the basins through canals, many of which were built by the Pharaohs. Even then the economic consequences of a deficient annual flood were recognized. Lake Maeris, which according to Herodotus was an ancient storage reservoir, is said to have had an area of 30,000 acres. In India, the British found at the time of their occupancy of the Presidency of Madras about 50,000 reservoirs for irrigation, many believed to be of ancient construction. 3/ During the period 115-130 A. D. reservoirs were built to improve the water-supply of Athens. Much has been written concerning the elaborate collection and distribution system built to supply Rome, and parts of it remain to this day as monuments to the engineering skill employed by the Romans in solving the problem of large-scale municipal water-supplies.

  9. Reasons for reservoir effect variability

    DEFF Research Database (Denmark)

    Philippsen, Bente


    , aquatic plants and fish from the rivers Alster and Trave range between zero and about 3,000 radiocarbon years. The reservoir age of water DIC depends to a large extent on the origin of the water and is for example correlated with precipitation amounts. These short-term variations are smoothed out in water...

  10. Policy Considerations for Greenhouse Gas Emissions from Freshwater Reservoirs

    Directory of Open Access Journals (Sweden)

    Kirsi Mäkinen


    Full Text Available Emerging concern over greenhouse gas (GHG emissions from wetlands has prompted calls to address the climate impact of dams in climate policy frameworks. Existing studies indicate that reservoirs can be significant sources of emissions, particularly in tropical areas. However, knowledge on the role of dams in overall national emission levels and abatement targets is limited, which is often cited as a key reason for political inaction and delays in formulating appropriate policies. Against this backdrop, this paper discusses the current role of reservoir emissions in existing climate policy frameworks. The distance between a global impact on climate and a need for local mitigation measures creates a challenge for designing appropriate mechanisms to combat reservoir emissions. This paper presents a range of possible policy interventions at different scales that could help address the climate impact of reservoirs. Reservoir emissions need to be treated like other anthropogenic greenhouse gases. A rational treatment of the issue requires applying commonly accepted climate change policy principles as well as promoting participatory water management plans through integrated water resource management frameworks. An independent global body such as the UN system may be called upon to assess scientific information and develop GHG emissions policy at appropriate levels.

  11. The influence of a severe reservoir drawdown on springtime zooplankton and larval fish assemblages in Red Willow Reservoir, Nebraska (United States)

    DeBoer, Jason A.; Webber, Christa M.; Dixon, Taylor A.; Pope, Kevin L.


    Reservoirs can be dynamic systems, often prone to unpredictable and extreme water-level fluctuations, and can be environments where survival is difficult for zooplankton and larval fish. Although numerous studies have examined the effects of extreme reservoir drawdown on water quality, few have examined extreme drawdown on both abiotic and biotic characteristics. A fissure in the dam at Red Willow Reservoir in southwest Nebraska necessitated an extreme drawdown; the water level was lowered more than 6 m during a two-month period, reducing reservoir volume by 76%. During the subsequent low-water period (i.e., post-drawdown), spring sampling (April–June) showed dissolved oxygen concentration was lower, while turbidity and chlorophyll-a concentration were greater, relative to pre-drawdown conditions. Additionally, there was an overall increase in zooplankton density, although there were differences among taxa, and changes in mean size among taxa, relative to pre-drawdown conditions. Zooplankton assemblage composition had an average dissimilarity of 19.3% from pre-drawdown to post-drawdown. The ratio of zero to non-zero catches was greater post-drawdown for larval common carp and for all larval fishes combined, whereas we observed no difference for larval gizzard shad. Larval fish assemblage composition had an average dissimilarity of 39.7% from pre-drawdown to post-drawdown. Given the likelihood that other dams will need repair or replacement in the near future, it is imperative for effective reservoir management that we anticipate the likely abiotic and biotic responses of reservoir ecosystems as these management actions will continue to alter environmental conditions in reservoirs.

  12. A numerical investigation of combined heat storage and extraction in deep geothermal reservoirs

    DEFF Research Database (Denmark)

    Major, Márton; Poulsen, Søren Erbs; Balling, Niels


    Heat storage capabilities of deep sedimentary geothermal reservoirs are evaluated through numerical model simulations. We combine storage with heat extraction in a doublet well system when storage phases are restricted to summer months. The effects of stored volume and annual repetition on energy...... efficiency. Additional simulations concerning pressure build-up in the reservoir are carried out to show that safety levels may not be reached. Reservoir characteristics are inspired by Danish geothermal conditions, but results are assumed to have more general validity. Thus, deep sedimentary reservoirs...

  13. Minimal Flavor Constraints for Technicolor

    DEFF Research Database (Denmark)

    Sakuma, Hidenori; Sannino, Francesco


    We analyze the constraints on the the vacuum polarization of the standard model gauge bosons from a minimal set of flavor observables valid for a general class of models of dynamical electroweak symmetry breaking. We will show that the constraints have a strong impact on the self-coupling and mas......We analyze the constraints on the the vacuum polarization of the standard model gauge bosons from a minimal set of flavor observables valid for a general class of models of dynamical electroweak symmetry breaking. We will show that the constraints have a strong impact on the self...

  14. Constraint Programming for Context Comprehension

    DEFF Research Database (Denmark)

    Christiansen, Henning


    A close similarity is demonstrated between context comprehension, such as discourse analysis, and constraint programming. The constraint store takes the role of a growing knowledge base learned throughout the discourse, and a suitable con- straint solver does the job of incorporating new pieces...... of knowledge. The language of Constraint Handling Rules, CHR, is suggested for defining constraint solvers that reflect “world knowledge” for the given domain, and driver algorithms may be ex- pressed in Prolog or additional rules of CHR. It is argued that this way of doing context comprehension is an instance...

  15. Coverage-based constraints for IMRT optimization (United States)

    Mescher, H.; Ulrich, S.; Bangert, M.


    Radiation therapy treatment planning requires an incorporation of uncertainties in order to guarantee an adequate irradiation of the tumor volumes. In current clinical practice, uncertainties are accounted for implicitly with an expansion of the target volume according to generic margin recipes. Alternatively, it is possible to account for uncertainties by explicit minimization of objectives that describe worst-case treatment scenarios, the expectation value of the treatment or the coverage probability of the target volumes during treatment planning. In this note we show that approaches relying on objectives to induce a specific coverage of the clinical target volumes are inevitably sensitive to variation of the relative weighting of the objectives. To address this issue, we introduce coverage-based constraints for intensity-modulated radiation therapy (IMRT) treatment planning. Our implementation follows the concept of coverage-optimized planning that considers explicit error scenarios to calculate and optimize patient-specific probabilities q(\\hat{d}, \\hat{v}) of covering a specific target volume fraction \\hat{v} with a certain dose \\hat{d} . Using a constraint-based reformulation of coverage-based objectives we eliminate the trade-off between coverage and competing objectives during treatment planning. In-depth convergence tests including 324 treatment plan optimizations demonstrate the reliability of coverage-based constraints for varying levels of probability, dose and volume. General clinical applicability of coverage-based constraints is demonstrated for two cases. A sensitivity analysis regarding penalty variations within this planing study based on IMRT treatment planning using (1) coverage-based constraints, (2) coverage-based objectives, (3) probabilistic optimization, (4) robust optimization and (5) conventional margins illustrates the potential benefit of coverage-based constraints that do not require tedious adjustment of target volume objectives.

  16. Reservoir Cathode for Electric Space Propulsion Project (United States)

    National Aeronautics and Space Administration — We propose a reservoir cathode to improve performance in both ion and Hall-effect thrusters. We propose to adapt our existing reservoir cathode technology to this...

  17. 49 CFR 236.792 - Reservoir, equalizing. (United States)


    ... Reservoir, equalizing. An air reservoir connected with and adding volume to the top portion of the equalizing piston chamber of the automatic brake valve, to provide uniform service reductions in brake pipe...

  18. Dissolved methane in Indian freshwater reservoirs

    Digital Repository Service at National Institute of Oceanography (India)

    Narvenkar, G.; Naqvi, S.W.A.; Kurian, S.; Shenoy, D.M.; Pratihary, A.K.; Naik, H.; Patil, S.; Sarkar, A.; Gauns, M.

    Emission of methane (CH4), a potent greenhouse gas, from tropical reservoirs is of interest because such reservoirs experience conducive conditions for CH4 production through anaerobic microbial activities. It has been suggested that Indian...

  19. The Methane Hydrate Reservoir System (United States)

    Flemings, P. B.; Liu, X.


    We use multi phase flow modeling and field examples (Hydrate Ridge, offshore Oregon and Blake Ridge, offshore North Carolina) to demonstrate that the methane hydrate reservoir system links traditional and non- traditional hydrocarbon system components: free gas flow is a fundamental control on this system. As in a traditional hydrocarbon reservoir, gas migrates into the hydrate reservoir as a separate phase (secondary migration) where it is trapped in a gas column beneath the base of the hydrate layer. With sufficient gas supply, buoyancy forces exceed either the capillary entry pressure of the cap rock or the fracture strength of the cap rock, and gas leaks into the hydrate stability zone, or cap rock. When gas enters the hydrate stability zone and forms hydrate, it becomes a very non traditional reservoir. Free gas forms hydrate, depletes water, and elevates salinity until pore water is too saline for further hydrate formation: salinity and hydrate concentration increase upwards from the base of the regional hydrate stability zone (RHSZ) to the seafloor and the base of the hydrate stability zone has significant topography. Gas chimneys couple the free gas zone to the seafloor through high salinity conduits that are maintained at the three-phase boundary by gas flow. As a result, significant amounts of gaseous methane can bypass the RHSZ, which implies a significantly smaller hydrate reservoir than previously envisioned. Hydrate within gas chimneys lie at the three-phase boundary and thus small increases in temperature or decreases in pressure can immediately transport methane into the ocean. This type of hydrate deposit may be the most economical for producing energy because it has very high methane concentrations (Sh > 70%) located near the seafloor, which lie on the three-phase boundary.

  20. Understanding the Role of Reservoir Size on Probable Maximum Precipitation (United States)

    Woldemichael, A. T.; Hossain, F.


    This study addresses the question 'Does surface area of an artificial reservoir matter in the estimation of probable maximum precipitation (PMP) for an impounded basin?' The motivation of the study was based on the notion that the stationarity assumption that is implicit in the PMP for dam design can be undermined in the post-dam era due to an enhancement of extreme precipitation patterns by an artificial reservoir. In addition, the study lays the foundation for use of regional atmospheric models as one way to perform life cycle assessment for planned or existing dams to formulate best management practices. The American River Watershed (ARW) with the Folsom dam at the confluence of the American River was selected as the study region and the Dec-Jan 1996-97 storm event was selected for the study period. The numerical atmospheric model used for the study was the Regional Atmospheric Modeling System (RAMS). First, the numerical modeling system, RAMS, was calibrated and validated with selected station and spatially interpolated precipitation data. Best combinations of parameterization schemes in RAMS were accordingly selected. Second, to mimic the standard method of PMP estimation by moisture maximization technique, relative humidity terms in the model were raised to 100% from ground up to the 500mb level. The obtained model-based maximum 72-hr precipitation values were named extreme precipitation (EP) as a distinction from the PMPs obtained by the standard methods. Third, six hypothetical reservoir size scenarios ranging from no-dam (all-dry) to the reservoir submerging half of basin were established to test the influence of reservoir size variation on EP. For the case of the ARW, our study clearly demonstrated that the assumption of stationarity that is implicit the traditional estimation of PMP can be rendered invalid to a large part due to the very presence of the artificial reservoir. Cloud tracking procedures performed on the basin also give indication of the

  1. Drought and reservoirs: intended benefits and unintended consequences (United States)

    Di Baldassarre, Giuliano; AghaKouchak, Amir; Rangecroft, Sally; Wanders, Niko; Kuil, Linda; Veldkamp, Ted; van Loon, Anne


    Socioeconomic drought can be broadly defined as a condition whereby water demand cannot be satisfied by water supply. Here we posit that while reservoirs often alleviate socioeconomic drought, they can lead to unintended consequences in the medium-long term. Losses caused by socioeconomic drought tend to trigger public pressure for action, which can result in the introduction or expansion of reservoirs to store more water during high flow conditions, and release it during low flow conditions. In the short term, increasing reservoir storage is often beneficial because frequency, magnitude, and duration of drought can be significantly reduced. Yet, it is important to note that reservoirs may fail in mitigating major, prolonged drought, because reservoir storage is unavoidably limited. In the medium-long term, two main dynamics tend to emerge, which often generate unintended consequences. The first one, termed here as "supply-demand cycle", is when increasing water supply triggers additional development and thus generates higher demand, which then offsets the benefit of reservoirs as a water supply source. This is a self-reinforcing feedback, or vicious cycle, as the occurrence of a new socioeconomic drought will then likely trigger further expansion of reservoir storage to, again, increase water supply. A second dynamic, termed here as "reservoir effect" (after White's "levee effect"), is when extended periods of abundant water supply, secured by reservoirs, generate a decline of coping capacities through increased competition for water and reduced shocks to the system, which in turn increases the vulnerability of the system to socio-economic drought. In other words, while a frequent experience of water shortages can help keep high levels of preparedness, some elements of system's resilience can be lost when minor-to-moderate events are avoided. As a result, the development of reservoirs can generate a shift from frequent socioeconomic drought conditions to rare

  2. Fractured Petroleum Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Firoozabadi, Dr. Abbas


    In this report the results of experiments of water injection in fractured porous media comprising a number of water-wet matrix blocks are reported for the first time. The blocks experience an advancing fracture-water level (FWL). Immersion-type experiments are performed for comparison; the dominant recovery mechanism changed from co-current to counter-current imbibition when the boundary conditions changed from advancing FWL to immersion-type. Single block experiments of co-current and counter-current imbibition was performed and co-current imbibition leads to more efficient recovery was found.

  3. Constraint rescaling in refined algebraic quantisation: Momentum constraint

    International Nuclear Information System (INIS)

    Louko, Jorma; Martinez-Pascual, Eric


    We investigate refined algebraic quantisation within a family of classically equivalent constrained Hamiltonian systems that are related to each other by rescaling a momentum-type constraint. The quantum constraint is implemented by a rigging map that is motivated by group averaging but has a resolution finer than what can be peeled off from the formally divergent contributions to the averaging integral. Three cases emerge, depending on the asymptotics of the rescaling function: (i) quantisation is equivalent to that with identity scaling; (ii) quantisation fails, owing to nonexistence of self-adjoint extensions of the constraint operator; (iii) a quantisation ambiguity arises from the self-adjoint extension of the constraint operator, and the resolution of this purely quantum mechanical ambiguity determines the superselection structure of the physical Hilbert space. Prospects of generalising the analysis to systems with several constraints are discussed.

  4. Reservoir characterization of the Snorre Field


    Gjestvang, Jørgen


    Master's thesis in Petroleum engineering The fluvial sandstone in the Snorre field consists of braided to meander streams deposited in arid and in humid climate that show a clear differences in the sedimentology and reservoir properties, especially the silt content in large part of the reservoir which decrease the reservoir properties and water saturation. The heterogeneity of these fluvial formations combined with the faulting history makes this reservoir highly complex with many local an...

  5. Reservoir resistivity characterization incorporating flow dynamics

    KAUST Repository

    Arango, Santiago


    Systems and methods for reservoir resistivity characterization are provided, in various aspects, an integrated framework for the estimation of Archie\\'s parameters for a strongly heterogeneous reservoir utilizing the dynamics of the reservoir are provided. The framework can encompass a Bayesian estimation/inversion method for estimating the reservoir parameters, integrating production and time lapse formation conductivity data to achieve a better understanding of the subsurface rock conductivity properties and hence improve water saturation imaging.

  6. Seismological Constraints on Geodynamics (United States)

    Lomnitz, C.


    Earth is an open thermodynamic system radiating heat energy into space. A transition from geostatic earth models such as PREM to geodynamical models is needed. We discuss possible thermodynamic constraints on the variables that govern the distribution of forces and flows in the deep Earth. In this paper we assume that the temperature distribution is time-invariant, so that all flows vanish at steady state except for the heat flow Jq per unit area (Kuiken, 1994). Superscript 0 will refer to the steady state while x denotes the excited state of the system. We may write σ 0=(J{q}0ṡX{q}0)/T where Xq is the conjugate force corresponding to Jq, and σ is the rate of entropy production per unit volume. Consider now what happens after the occurrence of an earthquake at time t=0 and location (0,0,0). The earthquake introduces a stress drop Δ P(x,y,z) at all points of the system. Response flows are directed along the gradients toward the epicentral area, and the entropy production will increase with time as (Prigogine, 1947) σ x(t)=σ 0+α {1}/(t+β )+α {2}/(t+β )2+etc A seismological constraint on the parameters may be obtained from Omori's empirical relation N(t)=p/(t+q) where N(t) is the number of aftershocks at time t following the main shock. It may be assumed that p/q\\sim\\alpha_{1}/\\beta times a constant. Another useful constraint is the Mexican-hat geometry of the seismic transient as obtained e.g. from InSAR radar interferometry. For strike-slip events such as Landers the distribution of \\DeltaP is quadrantal, and an oval-shaped seismicity gap develops about the epicenter. A weak outer triggering maxiμm is found at a distance of about 17 fault lengths. Such patterns may be extracted from earthquake catalogs by statistical analysis (Lomnitz, 1996). Finally, the energy of the perturbation must be at least equal to the recovery energy. The total energy expended in an aftershock sequence can be found approximately by integrating the local contribution over

  7. Tenth workshop on geothermal reservoir engineering: proceedings

    Energy Technology Data Exchange (ETDEWEB)


    The workshop contains presentations in the following areas: (1) reservoir engineering research; (2) field development; (3) vapor-dominated systems; (4) the Geysers thermal area; (5) well test analysis; (6) production engineering; (7) reservoir evaluation; (8) geochemistry and injection; (9) numerical simulation; and (10) reservoir physics. (ACR)

  8. 32 CFR 644.4 - Reservoir Projects. (United States)


    ... 32 National Defense 4 2010-07-01 2010-07-01 true Reservoir Projects. 644.4 Section 644.4 National... HANDBOOK Project Planning Civil Works § 644.4 Reservoir Projects. (a) Joint land acquisition policy for reservoir projects. The joint policies of the Department of the Interior and the Department of the Army...

  9. Amplitude various angles (AVA) phenomena in thin layer reservoir: Case study of various reservoirs

    International Nuclear Information System (INIS)

    thfloor, Physics Dept., FMIPA, Institut Teknologi Bandung (Indonesia); Rock Fluid Imaging Lab., Bandung (Indonesia))" data-affiliation=" (Wave Inversion and Subsurface Fluid Imaging Research Laboratory (WISFIR), Basic Science Center A 4thfloor, Physics Dept., FMIPA, Institut Teknologi Bandung (Indonesia); Rock Fluid Imaging Lab., Bandung (Indonesia))" >Nurhandoko, Bagus Endar B.; Susilowati


    Amplitude various offset is widely used in petroleum exploration as well as in petroleum development field. Generally, phenomenon of amplitude in various angles assumes reservoir’s layer is quite thick. It also means that the wave is assumed as a very high frequency. But, in natural condition, the seismic wave is band limited and has quite low frequency. Therefore, topic about amplitude various angles in thin layer reservoir as well as low frequency assumption is important to be considered. Thin layer reservoir means the thickness of reservoir is about or less than quarter of wavelength. In this paper, I studied about the reflection phenomena in elastic wave which considering interference from thin layer reservoir and transmission wave. I applied Zoeppritz equation for modeling reflected wave of top reservoir, reflected wave of bottom reservoir, and also transmission elastic wave of reservoir. Results show that the phenomena of AVA in thin layer reservoir are frequency dependent. Thin layer reservoir causes interference between reflected wave of top reservoir and reflected wave of bottom reservoir. These phenomena are frequently neglected, however, in real practices. Even though, the impact of inattention in interference phenomena caused by thin layer in AVA may cause inaccurate reservoir characterization. The relation between classes of AVA reservoir and reservoir’s character are different when effect of ones in thin reservoir and ones in thick reservoir are compared. In this paper, I present some AVA phenomena including its cross plot in various thin reservoir types based on some rock physics data of Indonesia

  10. Increasing Waterflooding Reservoirs in the Wilmington Oil Field through Improved Reservoir Characterization and Reservoir Management, Class III

    Energy Technology Data Exchange (ETDEWEB)

    Koerner, Roy; Clarke, Don; Walker, Scott; Phillips, Chris; Nguyen, John; Moos, Dan; Tagbor, Kwasi


    This project was intended to increase recoverable waterflood reserves in slope and basin reservoirs through improved reservoir characterization and reservoir management. The particular application of this project is in portions of Fault Blocks IV and V of the Wilmington Oil Field, in Long Beach, California, but the approach is widely applicable in slope and basin reservoirs, transferring technology so that it can be applied in other sections of the Wilmington field and by operators in other slope and basin reservoirs is a primary component of the project.

  11. Integrity Constraints in Trust Management

    NARCIS (Netherlands)

    Etalle, Sandro; Winsborough, William H.

    We introduce the use, monitoring, and enforcement of integrity constraints in trust managementstyle authorization systems. We consider what portions of the policy state must be monitored to detect violations of integrity constraints. Then we address the fact that not all participants in a trust

  12. Market segmentation using perceived constraints (United States)

    Jinhee Jun; Gerard Kyle; Andrew Mowen


    We examined the practical utility of segmenting potential visitors to Cleveland Metroparks using their constraint profiles. Our analysis identified three segments based on their scores on the dimensions of constraints: Other priorities--visitors who scored the highest on 'other priorities' dimension; Highly Constrained--visitors who scored relatively high on...

  13. Fixed Costs and Hours Constraints (United States)

    Johnson, William R.


    Hours constraints are typically identified by worker responses to questions asking whether they would prefer a job with more hours and more pay or fewer hours and less pay. Because jobs with different hours but the same rate of pay may be infeasible when there are fixed costs of employment or mandatory overtime premia, the constraint in those…


    Directory of Open Access Journals (Sweden)

    Cucu Sutarsyah


    Full Text Available The aim of the study is to identify and describe the vocabulary in reading materials and to seek if the texts are useful for reading skill development. A descriptive qualitative design was applied to obtain the data. Some available computer programs were used to find the description of vocabulary in the texts. It was found that the texts are dominated by low frequency words which compose 16.97% of the words in the texts. In terms of high frequency words occurring in the texts, function words dominate the texts. In the case of word levels, it was found that the texts being used have very limited number of words from GSL (West, 1953. The proportion of the first 1,000 words of GSL only comprises 44.6%. The data also show that the texts contain too large proportion of words which are not in the three levels (the first 2,000 and UWL. These words constitute account for 26.44% of the running words in the texts.  It is believed that the constraints are due to the selection of the texts which are made of a series of short-unrelated texts. This kind of text is subject to the accumulation of low frequency words especially those of content words and limited of words from GSL. It could also impede the development of students' reading skills and vocabulary enrichment.

  15. Conservation constraints on random matrices

    CERN Document Server

    Ma Wen Jong; Hsieh, J


    We study the random matrices constrained by the summation rules that are present in the Hessian of the potential energy surface in the instantaneous normal mode calculations, as a result of momentum conservation. In this paper, we analyse the properties related to such conservation constraints in two classes of real symmetric matrices: one with purely row-wise summation rules and the other with the constraints on the blocks of each matrix, which underscores partially the spatial dimension. We show explicitly that the constraints are removable by separating the degrees of freedom of the zero-eigenvalue modes. The non-spectral degrees of freedom under the constraints can be realized in terms of the ordinary constraint-free orthogonal symmetry but with the rank deducted by the block dimension. We propose that the ensemble of real symmetric matrices with full randomness, constrained by the summation rules, is equivalent to the Gaussian orthogonal ensemble (GOE) with lowered rank. Independent of the joint probabil...

  16. Studies Regarding the Safety in Operation of Ezer Reservoir

    Directory of Open Access Journals (Sweden)

    Balan Isabela


    Full Text Available The dam of the non-permanent reservoir Ezer, located on Jijia river is an earth dam with a maximum height of 6.18 m, which provides a global retention to the canopy of 10.330 million cubic meters. The dam founded on weak, muddy soils suffered in the years 1989 and 1992 downstream slope failures of the fillings. It was found that hydrostatic levels were high in the piezometric wells and that consolidation of the foundation soil was reduced. This paper presents a brief history of the dam and aspects regarding the behaviour monitoring of Ezer non-permanent reservoir during the years 2000-2012.

  17. Mercury content in fish from newly impounded reservoirs

    International Nuclear Information System (INIS)

    Frick, K.


    During the seventies elevated mercury content in fish was observed in newly created reservoirs although background levels were normal. The initial rise of reservoir mercury levels is probably caused by the dramatically increased amount of organic matter originating from flooded top-soil and vegetation. Mercury is introduced in the food-chain by methylating bacteria that utilize the surplus of organic matter. This microbial methylation is probably also favoured by reductions in oxygen content and pH that accompanies the decomposition of organic material. It is difficult to make reliable estimates of the duration and maximum levels of the elevated mercury levels since the end result is affected by several biological and chemical processes in combination. Variations may occur on the basis of the type and amount of flooded organic and inorganic material, water chemistry, specific combination of fish and residence time of reservoir water. All available preventive and ameliorating measures are untried in reservoir water bodies, at least in large scale experiments. Vegetation and top-soil stripping could be efficient but also very costly. Liming is a possible method in cases of ongoing or expected acidification. Addition of selenium is a potentially powerful way of lowering the mercury content in fish and this method is well suited to neutral water bodies. Large reductions in fish mercury content have been documented, but since selenium also has been shown to have strong negative effects on biota this method is not yet recommended. (57 refs.)

  18. preliminary assessment of heavy metal pollution of opa reservoir, ile

    African Journals Online (AJOL)

    big timmy

    Ni), Mercury (Hg), Cadmium. (Cd) and Selenium(Se) were determined in water and tissues of two fish species from Opa reservoir in Obafemi. Awolowo .... Table 1: Permissible Level of Heavy Metal in Raw Water/Drinking Water (mg/L).

  19. Multiparameter Elastic Full Waveform Inversion with Facies-based Constraints (United States)

    Zhang, Zhen-dong; Alkhalifah, Tariq; Naeini, Ehsan Zabihi; Sun, Bingbing


    Full waveform inversion (FWI) incorporates all the data characteristics to estimate the parameters described by the assumed physics of the subsurface. However, current efforts to utilize full waveform inversion beyond improved acoustic imaging, like in reservoir delineation, faces inherent challenges related to the limited resolution and the potential trade-off between the elastic model parameters. Some anisotropic parameters are insufficiently updated because of their minor contributions to the surface collected data. Adding rock physics constraints to the inversion helps mitigate such limited sensitivity, but current approaches to add such constraints are based on including them as a priori knowledge mostly valid around the well or as a global constraint for the whole area. Since similar rock formations inside the Earth admit consistent elastic properties and relative values of elasticity and anisotropy parameters (this enables us to define them as a seismic facies), utilizing such localized facies information in FWI can improve the resolution of inverted parameters. We propose a novel approach to use facies-based constraints in both isotropic and anisotropic elastic FWI. We invert for such facies using Bayesian theory and update them at each iteration of the inversion using both the inverted models and a prior information. We take the uncertainties of the estimated parameters (approximated by radiation patterns) into consideration and improve the quality of estimated facies maps. Four numerical examples corresponding to different acquisition, physical assumptions and model circumstances are used to verify the effectiveness of the proposed method.

  20. Multiparameter Elastic Full Waveform Inversion with Facies-based Constraints

    KAUST Repository

    Zhang, Zhendong


    Full waveform inversion (FWI) incorporates all the data characteristics to estimate the parameters described by the assumed physics of the subsurface. However, current efforts to utilize full waveform inversion beyond improved acoustic imaging, like in reservoir delineation, faces inherent challenges related to the limited resolution and the potential trade-off between the elastic model parameters. Some anisotropic parameters are insufficiently updated because of their minor contributions to the surface collected data. Adding rock physics constraints to the inversion helps mitigate such limited sensitivity, but current approaches to add such constraints are based on including them as a priori knowledge mostly valid around the well or as a global constraint for the whole area. Since similar rock formations inside the Earth admit consistent elastic properties and relative values of elasticity and anisotropy parameters (this enables us to define them as a seismic facies), utilizing such localized facies information in FWI can improve the resolution of inverted parameters. We propose a novel approach to use facies-based constraints in both isotropic and anisotropic elastic FWI. We invert for such facies using Bayesian theory and update them at each iteration of the inversion using both the inverted models and a prior information. We take the uncertainties of the estimated parameters (approximated by radiation patterns) into consideration and improve the quality of estimated facies maps. Four numerical examples corresponding to different acquisition, physical assumptions and model circumstances are used to verify the effectiveness of the proposed method.

  1. Development of Reservoir Characterization Techniques and Production Models for Exploiting Naturally Fractured Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Wiggins, M.L.; Evans, R.D.; Brown, R.L.; Gupta, A.


    This report focuses on integrating geoscience and engineering data to develop a consistent characterization of the naturally fractured reservoirs. During this reporting period, effort was focused on relating seismic data to reservoir properties of naturally fractured reservoirs, scaling well log data to generate interwell descriptors of these reservoirs, enhancing and debugging a naturally fractured reservoir simulator, and developing a horizontal wellbore model for use in the simulator.

  2. The radiocarbon reservoir age of the Chukchi Sea, Arctic Ocean (United States)

    Pearce, C.; Gyllencreutz, R.; West, G.; O'Regan, M.; Jakobsson, M.


    Radiocarbon (14C) dating is the standard method for obtaining the age of marine sediments of Holocene and late Pleistocene age. For accurate calibrations, however, this tool relies on precise knowledge of the local radiocarbon reservoir age of the surface ocean, i.e. the regional difference (ΔR) from the average global marine calibration dataset. This parameter has become impossible to measure from modern mollusk samples because of 14C contamination from extensive testing of thermo-nuclear bombs in the second half of the twentieth century. The local reservoir age can thus only be calculated from the radiocarbon age of samples collected before AD 1950 or from sediment records containing absolute age markers, derived from e.g. tephrochronology or paleomagnetism. Knowledge of the marine reservoir age in the Arctic Ocean is extremely sparse, and relies on work by only a few studies. No information exists for the entire East Siberian Sea, and the Chukchi Sea is represented solely by sites along the Alaskan coast. Here we present new radiocarbon measurements on historical mollusk collections from the East Siberian and Chukchi margins. Our results show a clear and consistent signal of "old" Pacific Water in the Chukchi Sea with ΔR values around 450 years. Towards the East Siberian Sea the values drop as Pacific Water has decreased influence further away from the Bering Strait. Complementing the modern data, we also provide constraints on the reservoir age during the late Holocene. These are based on tephrochronology and high resolution analyses of paleomagnetic secular variation from a sediment archive from Herald Canyon, Chukchi Sea.

  3. 4. International reservoir characterization technical conference

    Energy Technology Data Exchange (ETDEWEB)



    This volume contains the Proceedings of the Fourth International Reservoir Characterization Technical Conference held March 2-4, 1997 in Houston, Texas. The theme for the conference was Advances in Reservoir Characterization for Effective Reservoir Management. On March 2, 1997, the DOE Class Workshop kicked off with tutorials by Dr. Steve Begg (BP Exploration) and Dr. Ganesh Thakur (Chevron). Tutorial presentations are not included in these Proceedings but may be available from the authors. The conference consisted of the following topics: data acquisition; reservoir modeling; scaling reservoir properties; and managing uncertainty. Selected papers have been processed separately for inclusion in the Energy Science and Technology database.

  4. Reservoir microseismicity at the Ekofisk Oil Field

    Energy Technology Data Exchange (ETDEWEB)

    Rutledge, J.T.; Fairbanks, T.D. [Nambe Geophysical, Inc., Santa Fe, NM (United States); Albright, J.N. [Los Alamos National Lab., NM (United States); Boade, R.R. [Phillips Petroleum Co., Bartlesville, OK (United States); Dangerfield, J.; Landa, G.H. [Phillips Petroleum Co., Tananger (Norway)


    A triaxial, downhole geophone was deployed within the Ekofisk oil reservoir for monitoring ambient microseismicity as a test to determine if microearthquake signals generated from discrete shear failure of the reservoir rock could be detected. The results of the test were positive. During 104 hours of monitoring, 572 discrete events were recorded which have been identified as shear-failure microearthquakes. Reservoir microseismicity was detected at large distances (1000 m) from the monitor borehole and at rates (> 5 events per hour) which may allow practical characterization of the reservoir rock and overburden deformation induced by reservoir pressure changes.

  5. Smart Waterflooding in Carbonate Reservoirs

    DEFF Research Database (Denmark)

    Zahid, Adeel

    During the last decade, smart waterflooding has been developed into an emerging EOR technology both for carbonate and sandstone reservoirs that does not require toxic or expensive chemicals. Although it is widely accepted that different salinity brines may increase the oil recovery for carbonate...... reservoirs, understanding of the mechanism of this increase is still developing. To understand this smart waterflooding process, an extensive research has been carried out covering a broad range of disciplines within surface chemistry, thermodynamics of crude oil and brine, as well as their behavior...... that a heavy oil (that with a large fraction of heavy components) exhibited viscosity reduction in contact with brine, while a light crude oil exhibited emulsion formation. Most of reported high salinity waterflooding studies were carried out with outcrop chalk core plugs, and by performing spontaneous...

  6. Production Optimization of Oil Reservoirs

    DEFF Research Database (Denmark)

    Völcker, Carsten

    With an increasing demand for oil and diculties in nding new major oil elds, research on methods to improve oil recovery from existing elds is more necessary now than ever. The subject of this thesis is to construct ecient numerical methods for simulation and optimization of oil recovery...... programming (SQP) with line-search and BFGS approximations of the Hessian, and the adjoint method for ecient computation of the gradients. We demonstrate that the application of NMPC for optimal control of smart-wells has the potential to increase the economic value of an oil reservoir....... with emphasis on optimal control of water ooding with the use of smartwell technology. We have implemented immiscible ow of water and oil in isothermal reservoirs with isotropic heterogenous permeability elds. We use the method of lines for solution of the partial differential equation (PDE) system that governs...

  7. Multilevel techniques for Reservoir Simulation

    DEFF Research Database (Denmark)

    Christensen, Max la Cour

    for both variational upscaling and the construction of linear solvers. In particular, it is found to be beneficial (or even necessary) to apply an AMGe based multigrid solver to solve the upscaled problems. It is found that the AMGe upscaling changes the spectral properties of the matrix, which renders...... is extended to include a hybrid strategy, where FAS is combined with Newton’s method to construct a multilevel nonlinear preconditioner. This method demonstrates high efficiency and robustness. Second, an improved IMPES formulated reservoir simulator is implemented using a novel variational upscaling approach...... based on element-based Algebraic Multigrid (AMGe). In particular, an advanced AMGe technique with guaranteed approximation properties is used to construct a coarse multilevel hierarchy of Raviart-Thomas and L2 spaces for the Galerkin coarsening of a mixed formulation of the reservoir simulation...


    Directory of Open Access Journals (Sweden)

    M. A. Salmanov


    Full Text Available Aim. It is hardly possible to predict the continued stability of the watercourse ecosystems without the study of biological characteristics and composition of organisms inhabiting them. In the last 35-40 years, environmental conditions of the Mingachevir reservoir are determined by the stationary anthropogenic pressure. It was found that such components of plankton as algae, bacteria and fungi play a leading role in the transformation and migration of pollutants. The role of the three groups of organisms is very important in maintaining the water quality by elimination of pollutants. Among the organisms inhabiting the Mingachevir Reservoir, micromycetes have not yet been studied. Therefore, the study of the species composition and seasonal dynamics, peculiarities of their growth and development in the environment with the presence of some of the pollutants should be considered to date.Methods. In order to determine the role of micromycetes-migrants in the mineralization of organic substrates, as an active participant of self-purification process, we used water samples from the bottom sediments as well as decaying and skeletonized stalks of cane, reeds, algae, macrophytes, exuvia of insects and fish remains submerged in water.Findings. For the first time, we obtained the data on the quality and quantity of microscopic mycelial fungi in freshwater bodies on the example of the Mingachevir water reservoir; we also studied the possibilities for oxygenating the autochthonous organic matter of allochthonous origin with micromycetes-migrants.Conclusions. It was found that the seasonal development of micromycetes-migrants within the Mingachevir reservoir is characterized by an increase in the number of species in the summer and a gradual reduction in species diversity in the fall. 

  9. Measurement of Lake Roosevelt biota in relation to reservoir operations. 1991 Annual report

    International Nuclear Information System (INIS)

    Griffith, J.R.; McDowell, A.C.; Scholz, A.T.


    The purpose of this study was to collect biological data from Lake Roosevelt to be used in the design of a computer model that would predict biological responses to reservoir operations as part of the System Operation Review program. Major components of the Lake Roosevelt model included: quantification of impacts to phytoplankton, zooplanktons, benthic invertebrates, and fish caused by reservoir drawdowns and low water retention times; quantification of number, distribution, and use of fish food organisms in the reservoir by season; determination of seasonal growth of fish species as related to reservoir operations, prey abundance and utilization; and quantification of entrainment levels of zooplankton and fish as related to reservoir operations and water retention times. This report summarized the data collected on Lake Roosevelt for 1991 and includes limnological, zooplankton, benthic macroinvertebrate, fishery, and reservoir operation data. Discussions cover reservoir operation affect upon zooplankton, benthic macroinvertebrates, and fish. Reservoir operations brought reservoir elevations to a low of 1,221.7 in April, the result of power operations and a flood control shift from Dworshak Dam, in Idaho, to Grand Coulee Dam. Water retention times were correspondingly low reaching a minimum of 14.7 days on April 27th

  10. Measurement of Lake Roosevelt Biota in Relation to Reservoir Operations; 1991 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Griffith, Janelle R.; McDowell, Amy C.; Scholz, Allan T.


    The purpose of this study was to collect biological data from Lake Roosevelt to be used in the design of a computer model that would predict biological responses to reservoir operations as part of the System Operation Review program. Major components of the Lake Roosevelt model included: quantification of impacts to phytoplankton, zooplanktons, benthic invertebrates, and fish caused by reservoir drawdowns and low water retention times; quantification of number, distribution, and use of fish food organisms in the reservoir by season; determination of seasonal growth of fish species as related to reservoir operations, prey abundance and utilization; and quantification of entrainment levels of zooplankton and fish as related to reservoir operations and water retention times. This report summarized the data collected on Lake Roosevelt for 1991 and includes limnological, zooplankton, benthic macroinvertebrate, fishery, and reservoir operation data. Discussions cover reservoir operation affect upon zooplankton, benthic macroinvertebrates, and fish. Reservoir operations brought reservoir elevations to a low of 1,221.7 in April, the result of power operations and a flood control shift from Dworshak Dam, in Idaho, to Grand Coulee Dam. Water retention times were correspondingly low reaching a minimum of 14.7 days on April 27th.

  11. Identification and assessment of potential water quality impact factors for drinking-water reservoirs. (United States)

    Gu, Qing; Deng, Jinsong; Wang, Ke; Lin, Yi; Li, Jun; Gan, Muye; Ma, Ligang; Hong, Yang


    Various reservoirs have been serving as the most important drinking water sources in Zhejiang Province, China, due to the uneven distribution of precipitation and severe river pollution. Unfortunately, rapid urbanization and industrialization have been continuously challenging the water quality of the drinking-water reservoirs. The identification and assessment of potential impacts is indispensable in water resource management and protection. This study investigates the drinking water reservoirs in Zhejiang Province to better understand the potential impact on water quality. Altogether seventy-three typical drinking reservoirs in Zhejiang Province encompassing various water storage levels were selected and evaluated. Using fifty-two reservoirs as training samples, the classification and regression tree (CART) method and sixteen comprehensive variables, including six sub-sets (land use, population, socio-economy, geographical features, inherent characteristics, and climate), were adopted to establish a decision-making model for identifying and assessing their potential impacts on drinking-water quality. The water quality class of the remaining twenty-one reservoirs was then predicted and tested based on the decision-making model, resulting in a water quality class attribution accuracy of 81.0%. Based on the decision rules and quantitative importance of the independent variables, industrial emissions was identified as the most important factor influencing the water quality of reservoirs; land use and human habitation also had a substantial impact on water quality. The results of this study provide insights into the factors impacting the water quality of reservoirs as well as basic information for protecting reservoir water resources.

  12. Microbial quality and phylogenetic diversity of fresh rainwater and tropical freshwater reservoir. (United States)

    Kaushik, Rajni; Balasubramanian, Rajasekhar; Dunstan, Hugh


    The impact of rainwater on the microbial quality of a tropical freshwater reservoir through atmospheric wet deposition of microorganisms was studied for the first time. Reservoir water samples were collected at four different sampling points and rainwater samples were collected in the immediate vicinity of the reservoir sites for a period of four months (January to April, 2012) during the Northeast monsoon period. Microbial quality of all fresh rainwater and reservoir water samples was assessed based on the counts for the microbial indicators: Escherichia coli (E. coli), total coliforms, and Enterococci along with total heterotrophic plate counts (HPC). The taxonomic richness and phylogenetic relationship of the freshwater reservoir with those of the fresh rainwater were also assessed using 16 S rRNA gene clone library construction. The levels of E. coli were found to be in the range of 0 CFU/100 mL-75 CFU/100 mL for the rainwater, and were 10-94 CFU/100 mL for the reservoir water. The sampling sites that were influenced by highway traffic emissions showed the maximum counts for all the bacterial indicators assessed. There was no significant increase in the bacterial abundances observed in the reservoir water immediately following rainfall. However, the composite fresh rainwater and reservoir water samples exhibited broad phylogenetic diversity, including sequences representing Betaproteobacteria, Alphaproteobacteria, Gammaproteobacteria, Actinobacteria, Lentisphaerae and Bacteriodetes. Members of the Betaproteobacteria group were the most dominant in both fresh rainwater and reservoir water, followed by Alphaproteobacteria, Sphingobacteria, Actinobacteria and Gammaproteobacteria.

  13. The role of reservoir characterization in the reservoir management process (as reflected in the Department of Energy`s reservoir management demonstration program)

    Energy Technology Data Exchange (ETDEWEB)

    Fowler, M.L. [BDM-Petroleum Technologies, Bartlesville, OK (United States); Young, M.A.; Madden, M.P. [BDM-Oklahoma, Bartlesville, OK (United States)] [and others


    Optimum reservoir recovery and profitability result from guidance of reservoir practices provided by an effective reservoir management plan. Success in developing the best, most appropriate reservoir management plan requires knowledge and consideration of (1) the reservoir system including rocks, and rock-fluid interactions (i.e., a characterization of the reservoir) as well as wellbores and associated equipment and surface facilities; (2) the technologies available to describe, analyze, and exploit the reservoir; and (3) the business environment under which the plan will be developed and implemented. Reservoir characterization is the essential to gain needed knowledge of the reservoir for reservoir management plan building. Reservoir characterization efforts can be appropriately scaled by considering the reservoir management context under which the plan is being built. Reservoir management plans de-optimize with time as technology and the business environment change or as new reservoir information indicates the reservoir characterization models on which the current plan is based are inadequate. BDM-Oklahoma and the Department of Energy have implemented a program of reservoir management demonstrations to encourage operators with limited resources and experience to learn, implement, and disperse sound reservoir management techniques through cooperative research and development projects whose objectives are to develop reservoir management plans. In each of the three projects currently underway, careful attention to reservoir management context assures a reservoir characterization approach that is sufficient, but not in excess of what is necessary, to devise and implement an effective reservoir management plan.


    Energy Technology Data Exchange (ETDEWEB)

    Joel Walls; M.T. Taner; Naum Derzhi; Gary Mavko; Jack Dvorkin


    We have developed and tested technology for a new type of direct hydrocarbon detection. The method uses inelastic rock properties to greatly enhance the sensitivity of surface seismic methods to the presence of oil and gas saturation. These methods include use of energy absorption, dispersion, and attenuation (Q) along with traditional seismic attributes like velocity, impedance, and AVO. Our approach is to combine three elements: (1) a synthesis of the latest rock physics understanding of how rock inelasticity is related to rock type, pore fluid types, and pore microstructure, (2) synthetic seismic modeling that will help identify the relative contributions of scattering and intrinsic inelasticity to apparent Q attributes, and (3) robust algorithms that extract relative wave attenuation attributes from seismic data. This project provides: (1) Additional petrophysical insight from acquired data; (2) Increased understanding of rock and fluid properties; (3) New techniques to measure reservoir properties that are not currently available; and (4) Provide tools to more accurately describe the reservoir and predict oil location and volumes. These methodologies will improve the industry's ability to predict and quantify oil and gas saturation distribution, and to apply this information through geologic models to enhance reservoir simulation. We have applied for two separate patents relating to work that was completed as part of this project.

  15. Reservoir Model Information System: REMIS (United States)

    Lee, Sang Yun; Lee, Kwang-Wu; Rhee, Taehyun; Neumann, Ulrich


    We describe a novel data visualization framework named Reservoir Model Information System (REMIS) for the display of complex and multi-dimensional data sets in oil reservoirs. It is aimed at facilitating visual exploration and analysis of data sets as well as user collaboration in an easier way. Our framework consists of two main modules: the data access point module and the data visualization module. For the data access point module, the Phrase-Driven Grammar System (PDGS) is adopted for helping users facilitate the visualization of data. It integrates data source applications and external visualization tools and allows users to formulate data query and visualization descriptions by selecting graphical icons in a menu or on a map with step-by-step visual guidance. For the data visualization module, we implemented our first prototype of an interactive volume viewer named REMVR to classify and to visualize geo-spatial specific data sets. By combining PDGS and REMVR, REMIS assists users better in describing visualizations and exploring data so that they can easily find desired data and explore interesting or meaningful relationships including trends and exceptions in oil reservoir model data.

  16. Modeling compliant grasps exploiting environmental constraints


    Salvietti, Gionata; Malvezzi, Monica; Gioioso, Guido; Prattichizzo, Domenico


    In this paper we present a mathematical framework to describe the interaction between compliant hands and environmental constraints during grasping tasks. In the proposed model, we considered compliance at wrist, joint and contact level. We modeled the general case in which the hand is in contact with the object and the surrounding environment. All the other contact cases can be derived from the proposed system of equations. We performed several numerical simulation using the SynGrasp Matlab ...

  17. Reservoir Characterisation Using Wireline Evaluation And Poststack Seismic Inversion: A Lancelot Field, Southern North Sea, U.K. case study

    International Nuclear Information System (INIS)

    Mojisola, A.


    Improved reservoir characterization has been a major factor in the worldwide gain in oil recovery efficiencies over the last decades. This is because inadequate reservoir characterization, usually due to lack of appropriate tools can cause significant errors in petroleum reservoir performance prediction thereby preventing the full potential of a reservoir from being achieved. This work employs the use of wireline logs and the seismic inversion process to characterize the reservoirs in the Lancelot field. An initial reservoir analysis was carried out using the wireline evaluation. Five potential reservoirs were delineated. Thereafter reservoir parameters such as porosity, water saturation, water saturation, net-to-gross ratio of the delineated reservoirs were estimated. The seismic inversion process depends on four factors; the wavelet, the tie between the well logs and the seismic, the inversion algorithm employed and the initial model. Therefore before the main inversion, parameter tests were carried out to determine the best wavelet extraction algorithm and best inversion algorithm suited for he available data. A wavelet with a length of 70ms and a taper length of 20ms gave a close approximation of a zero phase wavelet with a stable spectrum and high dominant frequency. Based on quantitative assessment of the available inversion algorithms, the constrained blocky inversion produced the best result. Acoustic impedance, velocity and porosity sections were produced from the inverted input seismic. By incorporating geological and wireline evaluation results as constraints, the output from the inversion process were analysed. The result shows lateral variation in the reservoirs qualities of the delineated reservoirs. The seismic inversion process confirmed the Rotliegend sandstone as a prospect with a range of porosity predicted from the inversion

  18. Reservoir triggering seismicity in Greece: An evidence based review (United States)

    Pavlou, Kyriaki; Drakatos, George; Kouskouna, Vasiliki; Makropoulos, Konstantinos


    First filling and water fluctuation in artificial lakes and reservoirs are known causes of local seismicity. In Greece, 117 dams were built over the past 60 years, of which, however, only 22 have a capacity greater than 20x206cm3 and could thus affect seismicity in a meaningful way. Most of these larger dams have been constructed and operated by the Greek Public Power Corporation (PPC). The paper aims at a comprehensive review of all relevant studies, undertaken so far, and critically examines the evidence of reservoir triggering seismicity and possible accelerated earthquake occurrence provided. The main reservoirs examined include the Marathon, Kremasta, Pournari, Ilarion and Polyphyto artificial lakes, all of which have recorded seismic events associated with their filling and/or operation for the time period up to 2010. Seismic activity that correlates with maximum or minimum water level fluctuations leads to conclusions about a possible triggering seismicity due to a pore pressure diffusion (drained or un-drained response). In each case we review the cross-correlation coefficients between the reservoir levels and triggered events, and discuss the reasons for their association from an engineering geological (mechanical properties of rocks and formations) and seismological (triggered events) perspective. Our work suggests that, whilst in these cases PCC performs very well the task of hydrological and energy management of the reservoirs, it is crucially important to monitor and validate the daily seismicity at and around the artificial lakes for a better understanding of the upmost limit of triggered seismicity, and possible triggered landslides in the areas surrounding its main reservoirs.

  19. On the mechanisms of reservoir-induced seismicity (United States)

    Chen, Linyue

    Reservoir-induced seismicity (RIS) is caused by failure of pre-existing fractures due to reservoir impoundment or water level changes. More than one hundred RIS cases have been observed around the world, with the largest event reaching a magnitude M6.3. We have used detailed data collected around the world to study the mechanisms of RIS. Impoundment of a reservoir can change the frictional strength of a fault by elastic loading and by pore pressure diffusion. Stress and strength changes were calculated for 53 well-located earthquakes at Monticello Reservoir, South Carolina where detailed information of the fault planes and reservoir filling was known. The calculations showed that the diffusion of pore pressure is primarily responsible for the earthquakes, and that strength changes ≤0.1 MPa are enough to trigger RIS, indicating that large parts of crust are very near the state of critical failure. Monticello Reservoir was impounded in 1977 and the seismicity had decayed to background level by 1992. There was a sudden increase in seismicity starting at the end of 1996, at a time when there were no water level changes in the reservoir. This new seismicity occurred in isolated new hypocentral areas with no previous earthquakes. Analyses showed that the new seismicity was caused by the coupled effects of chemical reactions and pore pressure diffusion. Of the nineteen cases of RIS in China, fifteen are located in carbonate rocks. Chemical reactions between water and the carbonate rocks are responsible for the seismicity. Detailed spatial and temporal data of seismicity associated with reservoir impoundment, geothermal and oilfield exploitation and fluid injection were collected in the study. Hydraulic diffusivity and permeability values in the seismogenic areas were estimated from these data. The results showed that in the seismogenic areas with induced seismicity, hydraulic diffusivity values lie in the range of 0.1 to 10 m2/s and the permeability values are in the

  20. Location of the major seepage zones in ''Las alazanas'' dam reservoir

    International Nuclear Information System (INIS)

    Ortiz A, J.L.; Andreu, B.


    The reservoir of the ''Las Alazanas'' dam is located on the Soto La Marina River in the State of Tamaulipas. The filling of the reservoir began on December 24, 1971, and beginning on January 18, 1972, a 10 cm. daily (corresponding to an approximate 5 m 3 /sec outflow) fall in the reservoir level was noted, exclusively due to infiltration and evaporation. It is important to call attention to the existence of several springs below the curtain on the river approximately 8 kms. downstream. There is an increase in the outflow from these springs in accordance with raises in the reservoir level, causing thought about a connection between them. A study made with tracers to verify this connection and to locate the reservoir's infiltration zones is presented in this paper. A geophysical study was made to learn the thickness of the drifting material and the consequent possibility of carrying out some work tending to decrease infiltration. (author)

  1. Groundwater Salinity Simulation of a Subsurface Reservoir in Taiwan (United States)

    Fang, H. T.


    to input parameter. The simulation of water level and chloride concentration already showed the real situation, and the result can be applied to the future study of the Chi-Ken subsurface reservoir salinity problems.

  2. Limnological characteristics and trophic state of a newly created site: the Pareja Limno-reservoir (United States)

    Molina-Navarro, E.; Martínez-Pérez, S.; Sastre-Merlín, A.


    The creation of dams in the riverine zone of large reservoirs is an innovative action whose primary goal is to generate water bodies that ensure a stable level of water there. We have termed these bodies of water "limno-reservoirs" because their water level becomes constant and independent of the fluctuations occurring in the main reservoir. In addition, limno-reservoirs represent environmental initiatives with corrective and/or compensatory effects. Pareja Limno-reservoir, located near the left side of Entrepeñas Reservoir (Guadalajara province, central Spain), is one of the first initiatives of this type in Spain. We are investigating the hydrology, limnology, microbiology, siltation risk and other aspects of this site. This research has a special interest since the building of limno-reservoirs is rising in Spain. To acquire knowledge about their behavior may be helpful for further constructions. In fact, every new reservoir building project usually includes a limno-reservoir. Moreover, there are many initiatives related with the construction of this kind of hydraulic infrastructures in the reservoirs under exploitation. This work focuses on the limnological study of the Pareja Limno-reservoir. To conduct this research, twelve seasonal sample collections at two sampling points (the dam and inflow zones) have been made in Pareja Limno-reservoir, from spring 2008 to winter 2011. The primary goal of this study is to describe the limnological characteristics of the limno-reservoir. Special interest is placed in the study of the trophic state through different indicators (nutrients, transparency, phytoplankton and zooplankton populations), as the European Water Framework Directive objective is to achieve a "good ecological status" in every aquatic ecosystem by 2015. The results of the study show that the Pareja Limno-reservoir follows a warm monomictic water stratification pattern. Water was slightly alkaline and conductivity values were mostly over 1000 μS cm-1 due

  3. Optimal reservoir operation policies using novel nested algorithms (United States)

    Delipetrev, Blagoj; Jonoski, Andreja; Solomatine, Dimitri


    Historically, the two most widely practiced methods for optimal reservoir operation have been dynamic programming (DP) and stochastic dynamic programming (SDP). These two methods suffer from the so called "dual curse" which prevents them to be used in reasonably complex water systems. The first one is the "curse of dimensionality" that denotes an exponential growth of the computational complexity with the state - decision space dimension. The second one is the "curse of modelling" that requires an explicit model of each component of the water system to anticipate the effect of each system's transition. We address the problem of optimal reservoir operation concerning multiple objectives that are related to 1) reservoir releases to satisfy several downstream users competing for water with dynamically varying demands, 2) deviations from the target minimum and maximum reservoir water levels and 3) hydropower production that is a combination of the reservoir water level and the reservoir releases. Addressing such a problem with classical methods (DP and SDP) requires a reasonably high level of discretization of the reservoir storage volume, which in combination with the required releases discretization for meeting the demands of downstream users leads to computationally expensive formulations and causes the curse of dimensionality. We present a novel approach, named "nested" that is implemented in DP, SDP and reinforcement learning (RL) and correspondingly three new algorithms are developed named nested DP (nDP), nested SDP (nSDP) and nested RL (nRL). The nested algorithms are composed from two algorithms: 1) DP, SDP or RL and 2) nested optimization algorithm. Depending on the way we formulate the objective function related to deficits in the allocation problem in the nested optimization, two methods are implemented: 1) Simplex for linear allocation problems, and 2) quadratic Knapsack method in the case of nonlinear problems. The novel idea is to include the nested


    Directory of Open Access Journals (Sweden)

    G.W. Groves


    Full Text Available

    ENGLISH ABSTRACT: The technology of Constraint Programming is rapidly becoming a popular alternative for solving large-scale industry problems. This paper provides an introduction to Constraint Programming and to Constraint Logic Programming (CLP, an enabler of constraint programming. The use of Constraint Logic Programming is demonstrated by describing a system developed for scheduling university timetables. Timetabling problems have a high degree of algorithmic complexity (they are usually NP-Complete, and share features with scheduling problems encountered in industry. The system allows the declaration of both hard requirements, which must always be satisfied, and soft constraints which need not be satisfied, though this would be an advantage.

    AFRIKAANSE OPSOMMING: Hierdie artikel beskryf ’n familie van probleem-oplossingstegnieke bekend as “Constraint Programming”, wat al hoe meer gebruik word om groot-skaalse industriële probleme op te los. Die nut van hierdie tegnieke word gedemonstreer deur die beskrywing van ’n skeduleringsisteem om die roosters vir ’n universiteit te genereer. Roosterskeduleringsprobleme is in praktiese gevalle NP-volledig en deel baie eienskappe met industriële skeduleringsprobleme. Die sisteem wat hier beskryf word maak gebruik van beide harde beperkings (wat altyd bevredig moet word en sagte beperkings (bevrediging hiervan is wel voordelig maar dit is opsioneel.

  5. Optimization of practical trusses with constraints on eigenfrequencies, displacements, stresses, and buckling

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard; Nielsen, A.


    and the objective of the optimizations is minimum mass with constraints on (possibly multiple) eigenfrequencies, displacements, and stresses. For the case of stress constraints, we deal differently with tensile and compressive stresses, for which we control buckling on the element level. The stress constraints...


    Energy Technology Data Exchange (ETDEWEB)

    Timothy R. Carr; Don W. Green; G. Paul Willhite


    This annual report describes progress during the final year of the project entitled ''Improved Oil Recovery in Mississippian Carbonate Reservoirs in Kansas''. This project funded under the Department of Energy's Class 2 program targets improving the reservoir performance of mature oil fields located in shallow shelf carbonate reservoirs. The focus of the project was development and demonstration of cost-effective reservoir description and management technologies to extend the economic life of mature reservoirs in Kansas and the mid-continent. As part of the project, tools and techniques for reservoir description and management were developed, modified and demonstrated, including PfEFFER spreadsheet log analysis software. The world-wide-web was used to provide rapid and flexible dissemination of the project results through the Internet. A summary of demonstration phase at the Schaben and Ness City North sites demonstrates the effectiveness of the proposed reservoir management strategies and technologies. At the Schaben Field, a total of 22 additional locations were evaluated based on the reservoir characterization and simulation studies and resulted in a significant incremental production increase. At Ness City North Field, a horizontal infill well (Mull Ummel No.4H) was planned and drilled based on the results of reservoir characterization and simulation studies to optimize the location and length. The well produced excellent and predicted oil rates for the first two months. Unexpected presence of vertical shale intervals in the lateral resulted in loss of the hole. While the horizontal well was not economically successful, the technology was demonstrated to have potential to recover significant additional reserves in Kansas and the Midcontinent. Several low-cost approaches were developed to evaluate candidate reservoirs for potential horizontal well applications at the field scale, lease level, and well level, and enable the small

  7. Analysis of optical flow constraints. (United States)

    Del Bimbo, A; Nesi, P; Sanz, J C


    Different constraint equations have been proposed in the literature for the derivation of optical flow. Despite of the large number of papers dealing with computational techniques to estimate optical flow, only a few authors have investigated conditions under which these constraints exactly model the velocity field, that is, the perspective projection on the image plane of the true 3-D velocity. These conditions are analyzed under different hypotheses, and the departures of the constraint equations in modeling the velocity field are derived for different motion conditions. Experiments are also presented giving measures of these departures and of the induced errors in the estimation of the velocity field.

  8. Challenges of reservoir properties and production history matching in a CHOPS reservoir study

    Energy Technology Data Exchange (ETDEWEB)

    Alam, Mahbub [Department of Geoscience, University of Calgary (Canada)


    In order to meet increasing world energy demand, wells have to be drilled within very thin reservoir beds. This paper, we present one of the solutions for optimizing the reservoir characterization. Reservoir characterization is the process between the discovery of a property and the reservoir management phase. Principal data for reservoir modeling are: 4D Seismic interpretation, wireline log interpretation, core analysis, and petrophysical analysis. Reservoir conditions, perforation and completion technology are the key issues to the production rate of cold production. Reservoir modeling intends to minimize the risk factor, maximize production, and help determine the location for infill drillings. Cold heavy oil production with sand (CHOPS) is a method for enhancing primary production from heavy oil reservoirs. Gravitational forces, natural fluid pressure gradients and foamy oil flow phenomena are the major driving forces of the CHOPS mechanism. Finally, Reservoir characterization allows better understanding of permeability and porosity prediction.

  9. Limnological evaluation of the fisheries potentials and productivity of a small shallow tropical African reservoir. (United States)

    Mustapha, Moshood K


    Morphometrics and physico-chemical parameters of Oyun reservoir, Offa, Nigeria (a small shallow tropical African Reservoir) were used to estimate the potential fish yield of the reservoir according to the morpho-edaphic index (MEI). Physico-chemical characteristics of the water body were sampled monthly from three stations between January 2002 and December 2003 with standard methods. Estimates of the potential fish yield were obtained using the physico-chemical characteristics of the reservoir and the relationship Y = 23.281 MEI(0.447), where Y is the potential fish yield in kg/ha, MEI is the morpho-edaphic index (given in microS/cm and estimated by dividing the mean conductivity by the mean depth). The reservoir mean depth and conductivity values were 2.6m and 113.10 microS/cm respectively, while its potential fish yield was estimated at 125.72 kg/ha. This estimate was higher than other small shallower and larger African reservoirs. The reservoir high ionic content, high nutrient and dissolved oxygen levels, good pH, low level of pollution and shallow depth were responsible for the high estimate of the fish yield. In order to realize this high potential fish yield and sustainable exploration of the fisheries, effective management of the reservoir to curb eutrophication should be adopted, while other management practices such as stocking and conservation of desirable and indigenous fish species, implementation of fishing regulations and adoption of best management practices should be implemented.

  10. Deduction of reservoir operating rules for application in global hydrological models

    Directory of Open Access Journals (Sweden)

    H. M. Coerver


    Full Text Available A big challenge in constructing global hydrological models is the inclusion of anthropogenic impacts on the water cycle, such as caused by dams. Dam operators make decisions based on experience and often uncertain information. In this study information generally available to dam operators, like inflow into the reservoir and storage levels, was used to derive fuzzy rules describing the way a reservoir is operated. Using an artificial neural network capable of mimicking fuzzy logic, called the ANFIS adaptive-network-based fuzzy inference system, fuzzy rules linking inflow and storage with reservoir release were determined for 11 reservoirs in central Asia, the US and Vietnam. By varying the input variables of the neural network, different configurations of fuzzy rules were created and tested. It was found that the release from relatively large reservoirs was significantly dependent on information concerning recent storage levels, while release from smaller reservoirs was more dependent on reservoir inflows. Subsequently, the derived rules were used to simulate reservoir release with an average Nash–Sutcliffe coefficient of 0.81.

  11. Deduction of reservoir operating rules for application in global hydrological models (United States)

    Coerver, Hubertus M.; Rutten, Martine M.; van de Giesen, Nick C.


    A big challenge in constructing global hydrological models is the inclusion of anthropogenic impacts on the water cycle, such as caused by dams. Dam operators make decisions based on experience and often uncertain information. In this study information generally available to dam operators, like inflow into the reservoir and storage levels, was used to derive fuzzy rules describing the way a reservoir is operated. Using an artificial neural network capable of mimicking fuzzy logic, called the ANFIS adaptive-network-based fuzzy inference system, fuzzy rules linking inflow and storage with reservoir release were determined for 11 reservoirs in central Asia, the US and Vietnam. By varying the input variables of the neural network, different configurations of fuzzy rules were created and tested. It was found that the release from relatively large reservoirs was significantly dependent on information concerning recent storage levels, while release from smaller reservoirs was more dependent on reservoir inflows. Subsequently, the derived rules were used to simulate reservoir release with an average Nash-Sutcliffe coefficient of 0.81.

  12. Will building new reservoirs always help increase the water supply reliability? - insight from a modeling-based global study (United States)

    Zhuang, Y.; Tian, F.; Yigzaw, W.; Hejazi, M. I.; Li, H. Y.; Turner, S. W. D.; Vernon, C. R.


    More and more reservoirs are being build or planned in order to help meet the increasing water demand all over the world. However, is building new reservoirs always helpful to water supply? To address this question, the river routing module of Global Change Assessment Model (GCAM) has been extended with a simple yet physical-based reservoir scheme accounting for irrigation, flood control and hydropower operations at each individual reservoir. The new GCAM river routing model has been applied over the global domain with the runoff inputs from the Variable Infiltration Capacity Model. The simulated streamflow is validated at 150 global river basins where the observed streamflow data are available. The model performance has been significantly improved at 77 basins and worsened at 35 basins. To facilitate the analysis of additional reservoir storage impacts at the basin level, a lumped version of GCAM reservoir model has been developed, representing a single lumped reservoir at each river basin which has the regulation capacity of all reservoir combined. A Sequent Peak Analysis is used to estimate how much additional reservoir storage is required to satisfy the current water demand. For basins with water deficit, the water supply reliability can be improved with additional storage. However, there is a threshold storage value at each basin beyond which the reliability stops increasing, suggesting that building new reservoirs will not help better relieve the water stress. Findings in the research can be helpful to the future planning and management of new reservoirs.

  13. The grain size distribution of settled sediment within storage reservoir Otmuchów

    Directory of Open Access Journals (Sweden)

    Głowski Robert


    Full Text Available The grain size distribution of settled sediment within storage reservoir Otmuchów. The river Nysa Kłodzka is flowing through the flat-reduction Otmuchów. There are localized two storage reservoirs Otmuchów and Nysa. The first of these reservoirs have been constructed in the period 1928-1933 and the filling was completed in 1934. Reservoir Nysa was completed in 1971. Both reservoirs are located within walking distance of each other, creating since 1971 cascade. Reservoir Otmuchów is located above the Nysa reservoir what cause, that in the bowl of the Otmuchów reservoir, the significant part of transported by Nysa Kłodzka sediments is deposited. When established after the 1997 flood damming levels, summer and winter, the length of the reservoir Otmuchów is suitably from 4.5 to 5 km. At the maximum impoundment level and a maximal capacity of 130.45 million m3 the reservoir length reach approx. 7 km. From the analysis of the satellite image can be seen advancing silting of the reservoir Otmuchów especially in the estuary zone of the Nysa Kłodzka. Obtained archival data about changes of the sediment grain size distribution in the longitudinal reservoir profile cover only the region of the still capacity extending a distance of 3 km from the cross-section of the dam. In this zone the fine particles of the suspended load with characteristic diameters ranging from 0.030 to 0.088 mm were embedded. In 2010, the authors presented the results of preliminary analysis of the silting process of the reservoir Otmuchów. The authors pointed out that there is a lack of the data about the dimension of the particles embedded in the usable capacity and flood capacity reserve (above 3 km from the dam causing visible on satellite photo silting. This paper presents the results of the sediment grain size distribution in the usable capacity of the reservoir and in the estuary region of the Nysa Kłodzka located in flood capacity reserve, obtained from the

  14. Decentralized systems with design constraints

    CERN Document Server

    Mahmoud, Magdi S


    This volume provides a rigorous examination of the analysis, stability and control of large-scale systems, and addresses the difficulties that arise because of dimensionality, information structure constraints, parametric uncertainty and time-delays.

  15. Machine tongues. X. Constraint languages

    Energy Technology Data Exchange (ETDEWEB)

    Levitt, D.

    Constraint languages and programming environments will help the designer produce a lucid description of a problem domain, and then of particular situations and problems in it. Early versions of these languages were given descriptions of real world domain constraints, like the operation of electrical and mechanical parts. More recently, the author has automated a vocabulary for describing musical jazz phrases, using constraint language as a jazz improviser. General constraint languages will handle all of these domains. Once the model is in place, the system will connect built-in code fragments and algorithms to answer questions about situations; that is, to help solve problems. Bugs will surface not in code, but in designs themselves. 15 references.

  16. An Introduction to 'Creativity Constraints'

    DEFF Research Database (Denmark)

    Onarheim, Balder; Biskjaer, Michael Mose

    Constraints play a vital role as both restrainers and enablers in innovation processes by governing what the creative agent/s can and cannot do, and what the output can and cannot be. Notions of constraints are common in creativity research, but current contributions are highly dispersed due...... to no overall conceptual framing or shared terminology. This lack of unity hinders overt opportunities for cross-disciplinary interchange. We argue that an improved understanding of constraints in creativity holds a promising potential for advancements in creativity research across domains and disciplines. Here......, we give an overview of the growing, but incohesive body of research into creativity and constraints, which leads us to introduce ‘creativity constraints’ as a unifying concept to help bridge these disjoint contributions to facilitate cross- disciplinary interchange. Finally, we suggest key topics...

  17. Xe isotopic constraints on cycling of deep Earth volatiles (United States)

    Parai, R.; Mukhopadhyay, S.


    The modern deep Earth volatile budget reflects primordial volatiles delivered during accretion, radiogenic ingrowth of volatile species (e.g., 40Ar produced by 40K decay), outgassing in association with mantle processing, and regassing via subduction. The noble gases are unique volatile tracers in that they are chemically inert, but are thought to be trapped within hydrous alteration phases in downwelling lithologies. Noble gases thus provide a tracer of volatile transport between the deep Earth and surface reservoirs. Constraints on the fluxes of noble gases between deep Earth and surface reservoirs over time can accordingly be used to provide insight into temperature conditions at subduction zones, limits on volatile cycling, and the evolving distribution of major volatile species in terrestrial reservoirs over time. Xe isotope systematics in mantle-derived rocks show that 80-90% of the mantle Xe budget is derived from recycling of atmospheric Xe, indicating that atmospheric Xe is retained in subducting slabs beyond depths of magma generation in subduction zones over Earth history. We present an integrated model of Xe cycling between the mantle and atmosphere in association with mantle processing over Earth history. We test a wide variety of outgassing and regassing rates and take the evolution of the atmospheric Xe isotopic composition [e.g., 1] into account. Models in which the deep Earth transitions from a net outgassing to net regassing regime best satisfy Xe isotopic constraints from mantle-derived rocks [2-6]. [1] Avice et al., 2017; Nature Communications, 8; [2] Mukhopadhyay, 2012, Nature 486, 101-104; [3] Parai et al., 2012, EPSL 359-360, 227-239; [4] Parai and Mukhopadhay, 2015, G-cubed 16, 719-735; [5] Peto et al., 2013, EPSL 369-370, 13-23; [6] Tucker et al., 2012, EPSL 355-356, 244-254.

  18. Physical, chemical, and biological characteristics of Pueblo Reservoir, Colorado, 1985-89 (United States)

    Lewis, Michael E.; Edelmann, Patrick


    the reservoir inflow because of settling of particulate organic carbon. Levels of gross-alpha and gross-beta radioactivity generally were relatively low. In 7 of 31 samples collected, dissolved gross-alpha radioactivity, as natural uranium, exceeded 5 picocuries per liter, the level at which additional radiochemical analyses are recommended for drinking-water supplies. Potential sources of uranium in Pueblo Reservoir include weathering of exposed uranium ore deposits in the upper Arkansas River Basin and a uranium milling operation near Canon City.Phytoplankton densities and biovolumes measured during the winter, spring, and fall generally were indicative of a small to moderate algal biomass. Phytoplankton production tended to be largest during the summer. During the summer, phytoplankton densities and biovolumes generally were indicative of a moderate to large algal biomass. However, excessive algal production and biomass periodically occurred during the spring, summer, and fall. Three species of phytoplankton that are specifically associated with taste-and-odor problems in drinking water were identified on several occasions in water samples collected from Pueblo Reservoir. Reservoir operations and hydrodynamics can substantially affect processes that affect reservoir water quality. Stratification, underflow, and hypolimnetic withdrawals affect concentrations of dissolved solids, availability of nutrients, and concentrations of metals in the reservoir. Stratification impedes the mixing of epilimnetic and hypolimnetic waters, and the prevalent underflow that occurs during the summer results in a decrease in the potential dilution of inflowing river water with reservoir water. The underflow also decreases the maximum available nutrient load to the euphotic zone, which can, in turn, offset the maximum algal growth potential. Increased dissolved-solids, nutrient, and metal concentrations that occur in the hypolimnion during the summer are partially offset by hypolimnetic

  19. An Introduction to 'Creativity Constraints'

    DEFF Research Database (Denmark)

    Onarheim, Balder; Biskjær, Michael Mose


    to no overall conceptual framing or shared terminology. This lack of unity hinders overt opportunities for cross-disciplinary interchange. We argue that an improved understanding of constraints in creativity holds a promising potential for advancements in creativity research across domains and disciplines. Here...... and sub-concepts, including ‘late’, ‘self-imposed’, and ‘continua of creativity constraints’, to inform future cross-disciplinary work on creativity constraints....

  20. Natural Constraints to Species Diversification.

    Directory of Open Access Journals (Sweden)

    Eric Lewitus


    Full Text Available Identifying modes of species diversification is fundamental to our understanding of how biodiversity changes over evolutionary time. Diversification modes are captured in species phylogenies, but characterizing the landscape of diversification has been limited by the analytical tools available for directly comparing phylogenetic trees of groups of organisms. Here, we use a novel, non-parametric approach and 214 family-level phylogenies of vertebrates representing over 500 million years of evolution to identify major diversification modes, to characterize phylogenetic space, and to evaluate the bounds and central tendencies of species diversification. We identify five principal patterns of diversification to which all vertebrate families hold. These patterns, mapped onto multidimensional space, constitute a phylogenetic space with distinct properties. Firstly, phylogenetic space occupies only a portion of all possible tree space, showing family-level phylogenies to be constrained to a limited range of diversification patterns. Secondly, the geometry of phylogenetic space is delimited by quantifiable trade-offs in tree size and the heterogeneity and stem-to-tip distribution of branching events. These trade-offs are indicative of the instability of certain diversification patterns and effectively bound speciation rates (for successful clades within upper and lower limits. Finally, both the constrained range and geometry of phylogenetic space are established by the differential effects of macroevolutionary processes on patterns of diversification. Given these properties, we show that the average path through phylogenetic space over evolutionary time traverses several diversification stages, each of which is defined by a different principal pattern of diversification and directed by a different macroevolutionary process. The identification of universal patterns and natural constraints to diversification provides a foundation for understanding the

  1. Natural Constraints to Species Diversification. (United States)

    Lewitus, Eric; Morlon, Hélène


    Identifying modes of species diversification is fundamental to our understanding of how biodiversity changes over evolutionary time. Diversification modes are captured in species phylogenies, but characterizing the landscape of diversification has been limited by the analytical tools available for directly comparing phylogenetic trees of groups of organisms. Here, we use a novel, non-parametric approach and 214 family-level phylogenies of vertebrates representing over 500 million years of evolution to identify major diversification modes, to characterize phylogenetic space, and to evaluate the bounds and central tendencies of species diversification. We identify five principal patterns of diversification to which all vertebrate families hold. These patterns, mapped onto multidimensional space, constitute a phylogenetic space with distinct properties. Firstly, phylogenetic space occupies only a portion of all possible tree space, showing family-level phylogenies to be constrained to a limited range of diversification patterns. Secondly, the geometry of phylogenetic space is delimited by quantifiable trade-offs in tree size and the heterogeneity and stem-to-tip distribution of branching events. These trade-offs are indicative of the instability of certain diversification patterns and effectively bound speciation rates (for successful clades) within upper and lower limits. Finally, both the constrained range and geometry of phylogenetic space are established by the differential effects of macroevolutionary processes on patterns of diversification. Given these properties, we show that the average path through phylogenetic space over evolutionary time traverses several diversification stages, each of which is defined by a different principal pattern of diversification and directed by a different macroevolutionary process. The identification of universal patterns and natural constraints to diversification provides a foundation for understanding the deep-time evolution of

  2. On the constraints violation in forward dynamics of multibody systems

    Energy Technology Data Exchange (ETDEWEB)

    Marques, Filipe [University of Minho, Department of Mechanical Engineering (Portugal); Souto, António P. [University of Minho, Department of Textile Engineering (Portugal); Flores, Paulo, E-mail: [University of Minho, Department of Mechanical Engineering (Portugal)


    It is known that the dynamic equations of motion for constrained mechanical multibody systems are frequently formulated using the Newton–Euler’s approach, which is augmented with the acceleration constraint equations. This formulation results in the establishment of a mixed set of partial differential and algebraic equations, which are solved in order to predict the dynamic behavior of general multibody systems. The classical solution of the equations of motion is highly prone to constraints violation because the position and velocity constraint equations are not fulfilled. In this work, a general and comprehensive methodology to eliminate the constraints violation at the position and velocity levels is offered. The basic idea of the described approach is to add corrective terms to the position and velocity vectors with the intent to satisfy the corresponding kinematic constraint equations. These corrective terms are evaluated as a function of the Moore–Penrose generalized inverse of the Jacobian matrix and of the kinematic constraint equations. The described methodology is embedded in the standard method to solve the equations of motion based on the technique of Lagrange multipliers. Finally, the effectiveness of the described methodology is demonstrated through the dynamic modeling and simulation of different planar and spatial multibody systems. The outcomes in terms of constraints violation at the position and velocity levels, conservation of the total energy and computational efficiency are analyzed and compared with those obtained with the standard Lagrange multipliers method, the Baumgarte stabilization method, the augmented Lagrangian formulation, the index-1 augmented Lagrangian, and the coordinate partitioning method.

  3. Financial Constraints and Nominal Price Rigidities

    DEFF Research Database (Denmark)

    Menno, Dominik Francesco; Balleer, Almut; Hristov, Nikolay

    This paper investigates how financial market imperfections and the frequency of price adjustment interact. Based on new firm-level evidence for Germany, we document that financially constrained firms adjust prices more often than their unconstrained counterparts, both upwards and downwards. We show...... that these empirical patterns are consistent with a partial equilibrium menu-cost model with a working capital constraint. We then use the model to show how the presence of financial frictions changes profits and the price distribution of firms compared to a model without financial frictions. Our results suggest...... that tighter financial constraints are associated with higher nominal rigidities, higher prices and lower output. Moreover, in response to aggregate shocks, aggregate price rigidity moves substantially, the response of inflation is dampened, while output reacts more in the presence of financial frictions...

  4. Decoupling Coupled Constraints Through Utility Design

    Energy Technology Data Exchange (ETDEWEB)

    Li, N; Marden, JR


    Several multiagent systems exemplify the need for establishing distributed control laws that ensure the resulting agents' collective behavior satisfies a given coupled constraint. This technical note focuses on the design of such control laws through a game-theoretic framework. In particular, this technical note provides two systematic methodologies for the design of local agent objective functions that guarantee all resulting Nash equilibria optimize the system level objective while also satisfying a given coupled constraint. Furthermore, the designed local agent objective functions fit into the framework of state based potential games. Consequently, one can appeal to existing results in game-theoretic learning to derive a distributed process that guarantees the agents will reach such an equilibrium.

  5. Mercury bioaccumulation in the food web of Three Gorges Reservoir (China): Tempo-spatial patterns and effect of reservoir management

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jun [College of Fisheries, Huazhong Agricultural University, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Wuhan 430070 (China); Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan 430070 (China); Zhou, Qiong, E-mail: [College of Fisheries, Huazhong Agricultural University, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Wuhan 430070 (China); Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan 430070 (China); Yuan, Gailing; He, Xugang [College of Fisheries, Huazhong Agricultural University, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Wuhan 430070 (China); Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan 430070 (China); Xie, Ping [College of Fisheries, Huazhong Agricultural University, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Wuhan 430070 (China); Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology of China, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072 (China)


    Tempo-spatial patterns of mercury bioaccumulation and tropho-dynamics, and the potential for a reservoir effect were evaluated in the Three Gorges Reservoir (TGR, China) from 2011 to 2012, using total mercury concentrations (THg) and stable isotopes (δ{sup 13}C and δ{sup 15}N) of food web components (seston, aquatic invertebrates and fish). Hg concentrations in aquatic invertebrates and fish indicated a significant temporal trend associated with regular seasonal water-level manipulation. This includes water level lowering to allow for storage of water during the wet season (summer); a decrease of water levels from September to June providing a setting for flood storage. Hg concentrations in organisms were the highest after flooding. Higher Hg concentrations in fish were observed at the location farthest from the dam. Hg concentrations in water and sediment were correlated. Compared with the reservoirs of United States and Canada, TGR had lower trophic magnification factors (0.046–0.066), that are explained primarily by organic carbon concentrations in sediment, and the effect of “growth dilution”. Based on comparison before and after the impoundment of TGR, THg concentration in biota did not display an obvious long-term reservoir effect due to (i) short time since inundation, (ii) regular water discharge associated with water-level regulation, and/or (iii) low organic matter content in the sediment. - Highlights: • Hg concentrations were measured in biota of the main stem of 3 Gorges Reservoir. • Fish Hg concentration post-flood period > pre-flood period > flood period. • Fish Hg concentrations were the highest farthest from the dam. • THg in fish 2 years after inundation were the same as before impoundment. • Low biomagnification was ascribed to low DOC content in the sediment.

  6. Are Geotehrmal Reservoirs Stressed Out? (United States)

    Davatzes, N. C.; Laboso, R. C.; Layland-Bachmann, C. E.; Feigl, K. L.; Foxall, W.; Tabrez, A. R.; Mellors, R. J.; Templeton, D. C.; Akerley, J.


    Crustal permeability can be strongly influenced by developing connected networks of open fractures. However, the detailed evolution of a fracture network, its extent, and the persistence of fracture porosity are difficult to analyze. Even in fault-hosted geothermal systems, where heat is brought to the surface from depth along a fault, hydrothermal flow is heterogeneously distributed. This is presumably due to variations in fracture density, connectivity, and attitude, as well as variations in fracture permeability caused by sealing of fractures by precipitated cements or compaction. At the Brady Geothermal field in Nevada, we test the relationship between the modeled local stress state perturbed by dislocations representing fault slip or volume changes in the geothermal reservoir inferred from surface deformation measured by InSAR and the location of successful geothermal wells, hydrothermal activity, and seismicity. We postulate that permeability is favored in volumes that experience positive Coulomb stress changes and reduced compression, which together promote high densities of dilatant fractures. Conversely, permeability can be inhibited in locations where Coulomb stress is reduced, compression promotes compaction, or where the faults are poorly oriented in the stress field and consequently slip infrequently. Over geologic time scales spanning the development of the fault system, these local stress states are strongly influenced by the geometry of the fault network relative to the remote stress driving slip. At shorter time scales, changes in fluid pressure within the fracture network constituting the reservoir cause elastic dilations and contractions. We integrate: (1) direct observations of stress state and fractures in boreholes and the mapped geometry of the fault network; (2) evidence of permeability from surface hydrothermal features, production/injection wells and surface deformations related to pumping history; and (3) seismicity to test the

  7. Incorporation Between AHP and N-TSP for Plant Surveillance Routing with Multiple Constraints

    International Nuclear Information System (INIS)

    Djoko Hari Nugroho


    This paper observed plant on-line surveillance routing for maintenance management with multiple constraints using TSP (Traveling Salesman Problem). In the research N-TSP (nomadic TSP) type was used. In this case, on-line surveillance could be implemented on moving robot. Route for preventive maintenance management was observed sequentially per stage using multiple constraints (a) distance between components, and (b) failure probability of components using AHP (Analytical Hierarchy Process). Simulation was observed utilizing DURESS as a complex system. The simulation result showed that the route with single constraint distance between components represents the sequence of 1 - 6 - 2 - 4 - 3 - 5. Routing for DURESS with multiple constraints using incorporation of AHP and TSP showed that the first priority in the route is flow sensor FB2 with the value of comparation of 0.1042. The next priority is sequentially FB1, FA2, FA1, FA, FB, VB, VA, VA1, VA2, VB1, VB2, pump B, pump A, FR1, FR2, reservoir 2, and reservoir 1. Numerical experiment obtained that the incorporation between AHP and N-TSP has successfully constructed the surveillance routing with multiple constraints. (author)


    Directory of Open Access Journals (Sweden)

    I.Ol. Blynov


    Full Text Available Article compiling the main ideas of creating propagation-based constraint solver, theoretical basis of constraint programming and its implementation in IMS (Insertion Modeling System

  9. Financial Constraints and Exports: Evidence from Portuguese Manufacturing Firms

    Directory of Open Access Journals (Sweden)

    Armando Silva


    Full Text Available This paper analyses the links between financial constraints and firm export behaviour, at the firm level, by using data on Portuguese manufacturing enterprises. Previous empirical literature has not yet reached a consensus on these subjects and there is a great heterogeneity in measuring financial constraints. In line with a very recent trend, we approximate credit constraints by using a financial score built on eight variables. In order to assess the effects of exports on the financial status of firms we apply, for the first time to these types of studies, a propensity score matching with difference in differences. We find that new exporters show significant improvements in their financial situation.

  10. Inward FDI and credit constraints in the CEEC

    DEFF Research Database (Denmark)

    Rutkowski, Aleksander

    (FDI). In theory, foreign investment may only initially bring scarce capital and the subsequent investment can be financed locally. Foreign-owned companies may appear more attractive borrowers, and crowd out domestic firms from hostcountry imperfect capital markets. Both hypotheses are rejected because......This study attempts to find out, firstly, if domestically owned firms in Central and Eastern Europe confront higher credit constraints compared with the foreign-owned enterprises, and secondly, if the domestic enterprises' financial constraints are caused by the incoming foreign direct investments......-level regression methods, a direct one using perception-based assessment of the constraints and an indirect one with financial indicators....

  11. Nonlinear Multigrid for Reservoir Simulation

    DEFF Research Database (Denmark)

    Christensen, Max la Cour; Eskildsen, Klaus Langgren; Engsig-Karup, Allan Peter


    modeled after local linearization, leading to a nonlinear multigrid method in the form of the full-approximation scheme (FAS). It is demonstrated through numerical experiments that, without loss of robustness, the FAS method can outperform the conventional techniques in terms of algorithmic and numerical...... efficiency for a black-oil model. Furthermore, the use of the FAS method enables a significant reduction in memory usage compared with conventional techniques, which suggests new possibilities for improved large-scale reservoir simulation and numerical efficiency. Last, nonlinear multilevel preconditioning...

  12. A reservoir trap for antiprotons

    CERN Document Server

    Smorra, Christian; Franke, Kurt; Nagahama, Hiroki; Schneider, Georg; Higuchi, Takashi; Van Gorp, Simon; Blaum, Klaus; Matsuda, Yasuyuki; Quint, Wolfgang; Walz, Jochen; Yamazaki, Yasunori; Ulmer, Stefan


    We have developed techniques to extract arbitrary fractions of antiprotons from an accumulated reservoir, and to inject them into a Penning-trap system for high-precision measurements. In our trap-system antiproton storage times > 1.08 years are estimated. The device is fail-safe against power-cuts of up to 10 hours. This makes our planned comparisons of the fundamental properties of protons and antiprotons independent from accelerator cycles, and will enable us to perform experiments during long accelerator shutdown periods when background magnetic noise is low. The demonstrated scheme has the potential to be applied in many other precision Penning trap experiments dealing with exotic particles.

  13. Geological and production characteristics of strandplain/barrier island reservoirs in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Cole, E.L.; Fowler, M.; Jackson, S.; Madden, M.P.; Reeves, T.K.; Salamy, S.P.; Young, M.A.


    The Department of Energy`s (DOE`s) primary mission in the oil research program is to maximize the economically and environmentally sound recovery of oil from domestic reservoirs and to preserve access to this resource. The Oil Recovery Field Demonstration Program supports DOE`s mission through cost-shared demonstrations of improved Oil Recovery (IOR) processes and reservoir characterization methods. In the past 3 years, the DOE has issued Program Opportunity Notices (PONs) seeking cost-shared proposals for the three highest priority, geologically defined reservoir classes. The classes have been prioritized based on resource size and risk of abandonment. This document defines the geologic, reservoir, and production characteristics of the fourth reservoir class, strandplain/barrier islands. Knowledge of the geological factors and processes that control formation and preservation of reservoir deposits, external and internal reservoir heterogeneities, reservoir characterization methodology, and IOR process application can be used to increase production of the remaining oil-in-place (IOR) in Class 4 reservoirs. Knowledge of heterogeneities that inhibit or block fluid flow is particularly critical. Using the TORIS database of 330 of the largest strandplain/barrier island reservoirs and its predictive and economic models, the recovery potential which could result from future application of IOR technologies to Class 4 reservoirs was estimated to be between 1.0 and 4.3 billion barrels, depending on oil price and the level of technology advancement. The analysis indicated that this potential could be realized through (1) infill drilling alone and in combination with polymer flooding and profile modification, (2) chemical flooding (sufactant), and (3) thermal processes. Most of this future potential is in Texas, Oklahoma, and the Rocky Mountain region. Approximately two-thirds of the potentially recoverable resource is at risk of abandonment by the year 2000.

  14. Effect of reservoir heterogeneity on air injection performance in a light oil reservoir

    Directory of Open Access Journals (Sweden)

    Hu Jia


    Full Text Available Air injection is a good option to development light oil reservoir. As well-known that, reservoir heterogeneity has great effect for various EOR processes. This also applies to air injection. However, oil recovery mechanisms and physical processes for air injection in heterogeneous reservoir with dip angle are still not well understood. The reported setting of reservoir heterogeneous for physical model or simulation model of air injection only simply uses different-layer permeability of porous media. In practice, reservoir heterogeneity follows the principle of geostatistics. How much of contrast in permeability actually challenges the air injection in light oil reservoir? This should be investigated by using layered porous medial settings of the classical Dykstra-Parsons style. Unfortunately, there has been no work addressing this issue for air injection in light oil reservoir. In this paper, Reservoir heterogeneity is quantified based on the use of different reservoir permeability distribution according to classical Dykstra-Parsons coefficients method. The aim of this work is to investigate the effect of reservoir heterogeneity on physical process and production performance of air injection in light oil reservoir through numerical reservoir simulation approach. The basic model is calibrated based on previous study. Total eleven pseudo compounders are included in this model and ten complexity of reactions are proposed to achieve the reaction scheme. Results show that oil recovery factor is decreased with the increasing of reservoir heterogeneity both for air and N2 injection from updip location, which is against the working behavior of air injection from updip location. Reservoir heterogeneity sometimes can act as positive effect to improve sweep efficiency as well as enhance production performance for air injection. High O2 content air injection can benefit oil recovery factor, also lead to early O2 breakthrough in heterogeneous reservoir. Well

  15. Optimization of conventional rule curves coupled with hedging rules for reservoir operation

    DEFF Research Database (Denmark)

    Taghian, Mehrdad; Rosbjerg, Dan; Haghighi, Ali


    As a common approach to reservoir operating policies, water levels at the end of each time interval should be kept at or above the rule curve. In this study, the policy is captured using rationing of the target yield to reduce the intensity of severe water shortages. For this purpose, a hybrid...... to achieve the optimal water allocation and the target storage levels for reservoirs. As a case study, a multipurpose, multireservoir system in southern Iran is selected. The results show that the model has good performance in extracting the optimum policy for reservoir operation under both normal...

  16. Spatial and Temporal Variations of Water Quality and Trophic Status in Sembrong Reservoir, Johor (United States)

    Intan Najla Syed Hashim, Syarifah; Hidayah Abu Talib, Siti; Salleh Abustan, Muhammad


    A study of spatial and temporal variations on water quality and trophic status was conducted to determine the temporal (average reading by month) and spatial variations of water quality in Sembrong reservoir and to evaluate the trophic status of the reservoir. Water samples were collected once a month from November 2016 to June 2017 in seventeen (17) sampling stations at Sembrong Reservoir. Results obtained on the concentration of dissolved oxygen (DO), water temperature, pH and secchi depth had no significant differences compared to Total Phosphorus (TP) and chlorophyll-a. The water level has significantly decreased the value of the water temperature, pH and TP. The water quality of Sembrong reservoir is classified in Class II which is suitable for recreational uses and required conventional treatment while TSI indicates that sembrong reservoir was in lower boundary of classical eutrophic (TSI > 50).

  17. Spatial and Temporal Variations of Water Quality and Trophic Status in Sembrong Reservoir, Johor

    Directory of Open Access Journals (Sweden)

    Hashim Syarifah Intan Najla Syed


    Full Text Available A study of spatial and temporal variations on water quality and trophic status was conducted to determine the temporal (average reading by month and spatial variations of water quality in Sembrong reservoir and to evaluate the trophic status of the reservoir. Water samples were collected once a month from November 2016 to June 2017 in seventeen (17 sampling stations at Sembrong Reservoir. Results obtained on the concentration of dissolved oxygen (DO, water temperature, pH and secchi depth had no significant differences compared to Total Phosphorus (TP and chlorophyll-a. The water level has significantly decreased the value of the water temperature, pH and TP. The water quality of Sembrong reservoir is classified in Class II which is suitable for recreational uses and required conventional treatment while TSI indicates that sembrong reservoir was in lower boundary of classical eutrophic (TSI > 50.

  18. The effects of thermomechanical heterogeneities in island arc crust on time-dependent preeruptive stresses and the failure of an andesitic reservoir (United States)

    Gottsmann, J.; Odbert, H.


    Using ground deformation data from Soufrière Hills volcano (SHV), we present results from numerical modeling of the temperature- and time-dependent stress evolution in a mechanically heterogeneous crust prior to reservoir failure and renewed eruptive activity. The best fit models do not allow us to discriminate between a magmatic plumbing system consisting of either a single vertically elongated reservoir or a series of stacked reservoirs. A prolate reservoir geometry with volumes between 50 and 100 km3, reservoir pressure changes between 4 and 7 MPa, and reservoir volume changes between 0.03 and 0.04 km3 with magma compressibility between 4 × 10-11 and 1 × 10-9 Pa-1 provide plausible thermomechanical model parameters to explain the deformation time series; around an order of magnitude less overpressure than is generally inferred from homogeneous, elastic crustal models. Reservoir failure is predicted to occur at the crest of the reservoir except for reservoirs with highly compressible magma (≳4×10-9 Pa) for which subhorizontal sill formation is predicted upon reservoir failure. Introducing a deep-crustal hot zone modulates the partitioning of strains into the hotter underlying crust and results in a further reduction in overpressure estimates to values of around 1-2 MPa upon reservoir failure. Deduced volume fluxes are consistent with constraints from thermal modeling of active subvolcanic systems and imply dynamic failure of a compressible magma mush column feeding eruptions at SHV. Our interpretation of the results is that the combined thermomechanical effects of a deep-crustal hot zone and hot encasing rocks around a midcrustal andesitic reservoir fundamentally alter the time-dependent subsurface stress and strain partitioning upon reservoir priming. These effects substantially influence surface strains recorded by volcano geodetic monitoring.

  19. Stretch due to Penile Prosthesis Reservoir Migration

    Directory of Open Access Journals (Sweden)

    E. Baten


    Full Text Available A 43-year old patient presented to the emergency department with stretch, due to impossible deflation of the penile prosthesis, 4 years after successful implant. A CT-scan showed migration of the reservoir to the left rectus abdominis muscle. Refilling of the reservoir was inhibited by muscular compression, causing stretch. Removal and replacement of the reservoir was performed, after which the prosthesis was well-functioning again. Migration of the penile prosthesis reservoir is extremely rare but can cause several complications, such as stretch.

  20. Global Reservoir and Dam Database, Version 1 (GRanDv1): Reservoirs, Revision 01 (United States)

    National Aeronautics and Space Administration — The Global Reservoir and Dam (GRanD) Database, Version 1.1 contains 6,862 records of reservoirs and their associated dams with a cumulative storage capacity of 6,197...

  1. Role of reservoirs in sustained seismicity of Koyna-Warna region—a statistical analysis (United States)

    Yadav, Amrita; Gahalaut, Kalpna; Purnachandra Rao, N.


    Koyna-Warna region in western India is a globally recognized site of reservoir-triggered seismicity near the Koyna and Warna reservoirs. The region has been reported with several M > 5 earthquakes in the last five decades including M6.3 Koyna earthquake which is considered as the largest triggered earthquake worldwide. In the present study, a detailed statistical analysis has been done for long period earthquake catalogues during 1968-2004 of MERI and 2005-2012 of CSIR-NGRI to find out the spatio-temporal influence of the Koyna and Warna reservoirs impoundment on the seismicity of the region. Depending upon the earthquake clusters, we divided the region into three different zones and performed power spectrum and singular spectrum analysis (SSA) on them. For the time period 1983-1995, the earthquake zone near the Warna reservoir; for 1996-2004, the earthquake zone near the Koyna reservoir; and for 2005-2012, the earthquake zone near the Warna reservoir found to be influenced by the annual water level variations in the reservoirs that confirm the continuous role of both the reservoirs in the seismicity of the Koyna-Warna region.

  2. Potosi Reservoir Modeling; History and Recommendations

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Valerie; Leetaru, Hannes


    from using data from a single well in 2010 to the inclusion of data from three wells in 2013 which largely leverage the porosity and permeability logs plus knowledge of lost circulation zones. The first Potosi model (Potosi Geobody Model 2010) attempted to use the available seismic inversion data to inform the geomodel and predict vugular zones in advance of drilling VW1. Lost circulation zones in VW1 came in as the geologists predicted. The model was not implemented in subsequent simulation work. To date, reservoir models used for flow simulation work have relied predominately on Gaussian distributed properties (porosity and permeability) and have employed a single injection well. Potosi Model 2013b incorporated the new VW2 logs, and exhibited an extra level of sophistication by delineating the vugular intervals. This method added further realism that likely represents the best reservoir approximation to date. Where the 2010 reservoir models were 10 by 10 mi (16 by 16 km) in area, the 2013 models were expanded in size to 30 by 30 mi (48 by 48 km). The latest reservoir simulations show that a minimum of four injectors might be required to meet target injection rates. Still, there is data that requires further scrutiny and modeling methodologies that require testing for the Potosi Formation. This work is currently ongoing, and the next phase of the reservoir modeling intends to implement valuable data like porosity derived from seismic inversion, seismically derived geobodies, or a combination of both to further define vugular zones and the porosity distribution within the Potosi Formation. Understanding the dual porosity, dual permeability character of the Potosi remains the greatest challenge in representing this formation. Further analysis of the FMI* fullbore formation microimager data may aid in assessing this uncertainty. The Potosi Formation is indeed an interesting formation, and recommendations to further characterize it are included in the following list

  3. Derivation of Optimal Operating Rules for Large-scale Reservoir Systems Considering Multiple Trade-off (United States)

    Zhang, J.; Lei, X.; Liu, P.; Wang, H.; Li, Z.


    Flood control operation of multi-reservoir systems such as parallel reservoirs and hybrid reservoirs often suffer from complex interactions and trade-off among tributaries and the mainstream. The optimization of such systems is computationally intensive due to nonlinear storage curves, numerous constraints and complex hydraulic connections. This paper aims to derive the optimal flood control operating rules based on the trade-off among tributaries and the mainstream using a new algorithm known as weighted non-dominated sorting genetic algorithm II (WNSGA II). WNSGA II could locate the Pareto frontier in non-dominated region efficiently due to the directed searching by weighted crowding distance, and the results are compared with those of conventional operating rules (COR) and single objective genetic algorithm (GA). Xijiang river basin in China is selected as a case study, with eight reservoirs and five flood control sections within four tributaries and the mainstream. Furthermore, the effects of inflow uncertainty have been assessed. Results indicate that: (1) WNSGA II could locate the non-dominated solutions faster and provide better Pareto frontier than the traditional non-dominated sorting genetic algorithm II (NSGA II) due to the weighted crowding distance; (2) WNSGA II outperforms COR and GA on flood control in the whole basin; (3) The multi-objective operating rules from WNSGA II deal with the inflow uncertainties better than COR. Therefore, the WNSGA II can be used to derive stable operating rules for large-scale reservoir systems effectively and efficiently.

  4. EMSE: Synergizing EM and seismic data attributes for enhanced forecasts of reservoirs

    KAUST Repository

    Katterbauer, Klemens


    New developments of electromagnetic and seismic techniques have recently revolutionized the oil and gas industry. Time-lapse seismic data is providing engineers with tools to more accurately track the dynamics of multi-phase reservoir fluid flows. With the challenges faced in distinguishing between hydrocarbons and water via seismic methods, the industry has been looking at electromagnetic techniques in order to exploit the strong contrast in conductivity between hydrocarbons and water. Incorporating this information into reservoir simulation is expected to considerably enhance the forecasting of the reservoir, hence optimizing production and reducing costs. Conventional approaches typically invert the seismic and electromagnetic data in order to transform them into production parameters, before incorporating them as constraints in the history matching process and reservoir simulations. This makes automatization difficult and computationally expensive due to the necessity of manual processing, besides the potential artifacts. Here we introduce a new approach to incorporate seismic and electromagnetic data attributes directly into the history matching process. To avoid solving inverse problems and exploit information in the dynamics of the flow, we exploit petrophysical transformations to simultaneously incorporate time lapse seismic and electromagnetic data attributes using different ensemble Kalman-based history matching techniques. Our simulation results show enhanced predictability of the critical reservoir parameters and reduce uncertainties in model simulations, outperforming with only production data or the inclusion of either seismic or electromagnetic data. A statistical test is performed to confirm the significance of the results. © 2014 Elsevier B.V. All rights reserved.

  5. Seasonal assessment, treatment and removal of heavy metal concentrations in a tropical drinking water reservoir

    Directory of Open Access Journals (Sweden)

    Mustapha Moshood Keke


    Full Text Available Heavy metals are present in low concentrations in reservoirs, but seasonal anthropogenic activities usually elevate the concentrations to a level that could become a health hazard. The dry season concentrations of cadmium, copper, iron, lead, mercury, nickel and zinc were assessed from three sites for 12 weeks in Oyun reservoir, Offa, Nigeria. Triplicate surface water samples were collected and analysed using atomic absorption spectrophotometry. The trend in the level of concentrations in the three sites is site C > B > A, while the trend in the levels of the concentrations in the reservoir is Ni > Fe > Zn > Pb > Cd > Cu > Hg. Ni, Cd, Pb and Hg were found to be higher than the WHO guidelines for the metals in drinking water. The high concentration of these metals was from anthropogenic watershed run-off of industrial effluents, domestic sewages and agricultural materials into the reservoir coming from several human activities such as washing, bathing, fish smoking, especially in site C. The health effects of high concentration of these metals in the reservoir were highlighted. Methods for the treatment and removal of the heavy metals from the reservoir during water purification such as active carbon adsorption, coagulation-flocculation, oxidation-filtration, softening treatment and reverse osmosis process were highlighted. Other methods that could be used include phytoremediation, rhizofiltration, bisorption and bioremediation. Watershed best management practices (BMP remains the best solution to reduce the intrusion of the heavy metals from the watershed into the reservoir.

  6. Characterization of biocenoses in the storage reservoirs of liquid radioactive wastes of Mayak PA. Initial descriptive report

    International Nuclear Information System (INIS)

    Pryakhin, E.A.; Mokrov, Yu.G.; Tryapitsina, G.A.; Ivanov, I.A.; Osipov, D.I.; Atamanyuk, N.I.; Deryabina, L.V.; Shaposhnikova, I.A.; Shishkina, E.A.; Obvintseva, N.A.; Egoreichenkov, E.A.; Styazhkina, E.V.; Osipova, O.F.; Mogilnikova, N.I.; Andreev, S.S.; Tarasov, O.V.; Geras'kin, S.A.; Trapeznikov, A.V.; Akleyev, A.V.


    As a result of operation of the Mayak Production Association (Mayak PA), Chelyabinsk Oblast, Russia, an enterprise for production and separation of weapon-grade plutonium in the Soviet Union, ecosystems of a number of water bodies have been radioactively contaminated. The article presents information about the current state of ecosystems of 6 special industrial storage reservoirs of liquid radioactive waste from Mayak PA: reservoirs R-3, R-4, R-9, R-10, R-11 and R-17. At present the excess of the radionuclide content in the water of the studied reservoirs and comparison reservoirs (Shershnyovskoye and Beloyarskoye reservoirs) is 9 orders of magnitude for 90 Sr and 137 Cs, and 6 orders of magnitude for alpha-emitting radionuclides. According to the level of radioactive contamination, the reservoirs of the Mayak PA could be arranged in the ascending order as follows: R-11, R-10, R-4, R-3, R-17 and R-9. In 2007–2012 research of the status of the biocenoses of these reservoirs in terms of phytoplankton, zooplankton, bacterioplankton, zoobenthos, aquatic plants, ichthyofauna, avifauna parameters was performed. The conducted studies revealed decrease in species diversity in reservoirs with the highest levels of radioactive and chemical contamination. This article is an initial descriptive report on the status of the biocenoses of radioactively contaminated reservoirs of the Mayak PA, and is the first article in a series of publications devoted to the studies of the reaction of biocenoses of the fresh-water reservoirs of the Mayak PA to a combination of natural and man-made factors, including chronic radiation exposure. - Highlights: • The current state of storage reservoirs of liquid radioactive waste of the Mayak Production Association is presented. • Radionuclides contents in water and sediments of the reservoirs of Mayak PA are presented. • The status of the major ecological groups of hydrobionts of the given reservoirs is described.

  7. Multiparameter Elastic Full Waveform Inversion With Facies Constraints

    KAUST Repository

    Zhang, Zhendong


    Full waveform inversion (FWI) aims fully benefit from all the data characteristics to estimate the parameters describing the assumed physics of the subsurface. However, current efforts to utilize full waveform inversion as a tool beyond acoustic imaging applications, for example in reservoir analysis, faces inherent challenges related to the limited resolution and the potential trade-off between the elastic model parameters. Adding rock physics constraints does help to mitigate these issues, but current approaches to add such constraints are based on including them as a priori knowledge mostly valid around the well or as a boundary condition for the whole area. Since certain rock formations inside the Earth admit consistent elastic properties and relative values of elastic and anisotropic parameters (facies), utilizing such localized facies information in FWI can improve the resolution of inverted parameters. We propose a novel confidence map based approach to utilize the facies-based constraints in both isotropic and anisotropic elastic FWI. We invert for such a confidence map using Bayesian theory, in which the confidence map is updated at each iteration of the inversion using both the inverted models and a prior information. The numerical examples show that the proposed method can reduce the trade-offs and also can improve the resolution of the inverted elastic and anisotropic properties.

  8. Data assimilation with inequality constraints (United States)

    Thacker, W. C.

    If values of variables in a numerical model are limited to specified ranges, these restrictions should be enforced when data are assimilated. The simplest option is to assimilate without regard for constraints and then to correct any violations without worrying about additional corrections implied by correlated errors. This paper addresses the incorporation of inequality constraints into the standard variational framework of optimal interpolation with emphasis on our limited knowledge of the underlying probability distributions. Simple examples involving only two or three variables are used to illustrate graphically how active constraints can be treated as error-free data when background errors obey a truncated multi-normal distribution. Using Lagrange multipliers, the formalism is expanded to encompass the active constraints. Two algorithms are presented, both relying on a solution ignoring the inequality constraints to discover violations to be enforced. While explicitly enforcing a subset can, via correlations, correct the others, pragmatism based on our poor knowledge of the underlying probability distributions suggests the expedient of enforcing them all explicitly to avoid the computationally expensive task of determining the minimum active set. If additional violations are encountered with these solutions, the process can be repeated. Simple examples are used to illustrate the algorithms and to examine the nature of the corrections implied by correlated errors.

  9. Estimation of Bank Erosion Due To Reservoir Operation in Cascade (Case Study: Citarum Cascade Reservoir

    Directory of Open Access Journals (Sweden)

    Sri Legowo


    Full Text Available Sedimentation is such a crucial issue to be noted once the accumulated sediment begins to fill the reservoir dead storage, this will then influence the long-term reservoir operation. The sediment accumulated requires a serious attention for it may influence the storage capacity and other reservoir management of activities. The continuous inflow of sediment to the reservoir will decrease the capacity of reservoir storage, the reservoir value in use, and the useful age of reservoir. Because of that, the rate of the sediment needs to be delayed as possible. In this research, the delay of the sediment rate is considered based on the rate of flow of landslide of the reservoir slope. The rate of flow of the sliding slope can be minimized by way of each reservoir autonomous efforts. This effort can be performed through; the regulation of fluctuating rate of reservoir surface current that does not cause suddenly drawdown and upraising as well. The research model is compiled using the searching technique of Non Linear Programming (NLP.The rate of bank erosion for the reservoir variates from 0.0009 to 0.0048 MCM/year, which is no sigrificant value to threaten the life time of reservoir.Mean while the rate of watershed sediment has a significant value, i.e: 3,02 MCM/year for Saguling that causes to fullfill the storage capacity in 40 next years (from years 2008.

  10. Impact of Reservoir Operation to the Inflow Flood - a Case Study of Xinfengjiang Reservoir (United States)

    Chen, L.


    Building of reservoir shall impact the runoff production and routing characteristics, and changes the flood formation. This impact, called as reservoir flood effect, could be divided into three parts, including routing effect, volume effect and peak flow effect, and must be evaluated in a whole by using hydrological model. After analyzing the reservoir flood formation, the Liuxihe Model for reservoir flood forecasting is proposed. The Xinfengjiang Reservoir is studied as a case. Results show that the routing effect makes peak flow appear 4 to 6 hours in advance, volume effect is bigger for large flood than small one, and when rainfall focus on the reservoir area, this effect also increases peak flow largely, peak flow effect makes peak flow increase 6.63% to 8.95%. Reservoir flood effect is obvious, which have significant impact to reservoir flood. If this effect is not considered in the flood forecasting model, the flood could not be forecasted accurately, particularly the peak flow. Liuxihe Model proposed for Xinfengjiang Reservoir flood forecasting has a good performance, and could be used for real-time flood forecasting of Xinfengjiang Reservoir.Key words: Reservoir flood effect, reservoir flood forecasting, physically based distributed hydrological model, Liuxihe Model, parameter optimization

  11. A stochastic conflict resolution model for water quality management in reservoir river systems (United States)

    Kerachian, Reza; Karamouz, Mohammad


    In this paper, optimal operating rules for water quality management in reservoir-river systems are developed using a methodology combining a water quality simulation model and a stochastic GA-based conflict resolution technique. As different decision-makers and stakeholders are involved in the water quality management in reservoir-river systems, a new stochastic form of the Nash bargaining theory is used to resolve the existing conflict of interests related to water supply to different demands, allocated water quality and waste load allocation in downstream river. The expected value of the Nash product is considered as the objective function of the model which can incorporate the inherent uncertainty of reservoir inflow. A water quality simulation model is also developed to simulate the thermal stratification cycle in the reservoir, the quality of releases from different outlets as well as the temporal and spatial variation of the pollutants in the downstream river. In this study, a Varying Chromosome Length Genetic Algorithm (VLGA), which has computational advantages comparing to other alternative models, is used. VLGA provides a good initial solution for Simple Genetic Algorithms and comparing to Stochastic Dynamic Programming (SDP) reduces the number of state transitions checked in each stage. The proposed model, which is called Stochastic Varying Chromosome Length Genetic Algorithm with water Quality constraints (SVLGAQ), is applied to the Ghomrud Reservoir-River system in the central part of Iran. The results show, the proposed model for reservoir operation and waste load allocation can reduce the salinity of the allocated water demands as well as the salinity build-up in the reservoir.

  12. Tail Risk Constraints and Maximum Entropy

    Directory of Open Access Journals (Sweden)

    Donald Geman


    Full Text Available Portfolio selection in the financial literature has essentially been analyzed under two central assumptions: full knowledge of the joint probability distribution of the returns of the securities that will comprise the target portfolio; and investors’ preferences are expressed through a utility function. In the real world, operators build portfolios under risk constraints which are expressed both by their clients and regulators and which bear on the maximal loss that may be generated over a given time period at a given confidence level (the so-called Value at Risk of the position. Interestingly, in the finance literature, a serious discussion of how much or little is known from a probabilistic standpoint about the multi-dimensional density of the assets’ returns seems to be of limited relevance. Our approach in contrast is to highlight these issues and then adopt throughout a framework of entropy maximization to represent the real world ignorance of the “true” probability distributions, both univariate and multivariate, of traded securities’ returns. In this setting, we identify the optimal portfolio under a number of downside risk constraints. Two interesting results are exhibited: (i the left- tail constraints are sufficiently powerful to override all other considerations in the conventional theory; (ii the “barbell portfolio” (maximal certainty/ low risk in one set of holdings, maximal uncertainty in another, which is quite familiar to traders, naturally emerges in our construction.

  13. Games and teams with shared constraints. (United States)

    Kulkarni, Ankur A


    Energy systems of the future are envisaged to encompass multiple interacting autonomous entities. The theory of games provides the foundations for the design and analysis of such systems. This paper reviews models and results that would be of use for such analysis. Classically, games have involved players whose strategies are coupled only through the dependence of utility functions on strategies of other players. However, in many practical settings in the energy domain, system-level limitations bind the choices players can make. In 1965, Rosen ( Econometrica 33 , 520-534 (doi:10.2307/1911749)) pioneered the study of a class of games where there is a common constraint, called a shared constraint , that couples the strategies available to the players. We discuss how this seemingly benign extension has important ramifications, ranging from the very definition of an equilibrium concept, to other key issues such as existence, uniqueness and efficiency of equilibria. We show how the presence of a shared constraint naturally leads to notions of a price and forms the motivations for more recent models. Although most of the paper has the character of a survey, occasionally we also prove new results.This article is part of the themed issue 'Energy management: flexibility, risk and optimization'. © 2017 The Author(s).

  14. Current constraints on the cosmic growth history

    International Nuclear Information System (INIS)

    Bean, Rachel; Tangmatitham, Matipon


    We present constraints on the cosmic growth history with recent cosmological data, allowing for deviations from ΛCDM as might arise if cosmic acceleration is due to modifications to general relativity or inhomogeneous dark energy. We combine measures of the cosmic expansion history, from Type 1a supernovae, baryon acoustic oscillations, and the cosmic microwave background (CMB), with constraints on the growth of structure from recent galaxy, CMB, and weak lensing surveys along with integated Sachs Wolfe-galaxy cross correlations. Deviations from ΛCDM are parameterized by phenomenological modifications to the Poisson equation and the relationship between the two Newtonian potentials. We find modifications that are present at the time the CMB is formed are tightly constrained through their impact on the well-measured CMB acoustic peaks. By contrast, constraints on late-time modifications to the growth history, as might arise if modifications are related to the onset of cosmic acceleration, are far weaker, but remain consistent with ΛCDM at the 95% confidence level. For these late-time modifications we find that differences in the evolution on large and small scales could provide an interesting signature by which to search for modified growth histories with future wide angular coverage, large scale structure surveys.

  15. A quantum Szilard engine without heat from a thermal reservoir (United States)

    Hamed Mohammady, M.; Anders, Janet


    We study a quantum Szilard engine that is not powered by heat drawn from a thermal reservoir, but rather by projective measurements. The engine is constituted of a system { S }, a weight { W }, and a Maxwell demon { D }, and extracts work via measurement-assisted feedback control. By imposing natural constraints on the measurement and feedback processes, such as energy conservation and leaving the memory of the demon intact, we show that while the engine can function without heat from a thermal reservoir, it must give up at least one of the following features that are satisfied by a standard Szilard engine: (i) repeatability of measurements; (ii) invariant weight entropy; or (iii) positive work extraction for all measurement outcomes. This result is shown to be a consequence of the Wigner–Araki–Yanase theorem, which imposes restrictions on the observables that can be measured under additive conservation laws. This observation is a first-step towards developing ‘second-law-like’ relations for measurement-assisted feedback control beyond thermality.

  16. Notes on Timed Concurrent Constraint Programming

    DEFF Research Database (Denmark)

    Nielsen, Mogens; Valencia, Frank D.


    A constraint is a piece of (partial) information on the values of the variables of a system. Concurrent constraint programming (ccp) is a model of concurrency in which agents (also called processes) interact by telling and asking information (constraints) to and from a shared store (a constraint...

  17. Constraints on the creation of a HIMU-Like isotopic reservoir beneath New Zealand

    DEFF Research Database (Denmark)

    van der Meer, Quinten; Waight, Tod Earle; Scott, James


    and the intrusion of mafic dikes (~88 to 68 Ma). Subsequently, Zealandia has been punctuated by volumetrically minor, intermittent yet widespread intraplate magmatism from ~100 Ma through to recent times. This magmatism has typical OIB-like trace element abundances and radiogenic isotope compositions that trend...

  18. Analysis of environmental constraints on expanding reserves in current and future reservoirs in wetlands. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Harder, B.J.


    Louisiana wetlands require careful management to allow exploitation of non-renewable resources without destroying renewable resources. Current regulatory requirements have been moderately successful in meeting this goal by restricting development in wetland habitats. Continuing public emphasis on reducing environmental impacts of resource development is causing regulators to reassess their regulations and operators to rethink their compliance strategies. We examined the regulatory system and found that reducing the number of applications required by going to a single application process and having a coherent map of the steps required for operations in wetland areas would reduce regulatory burdens. Incremental changes can be made to regulations to allow one agency to be the lead for wetland permitting at minimal cost to operators. Operators need cost effective means of access that will reduce environmental impacts, decrease permitting time, and limit future liability. Regulators and industry must partner to develop incentive based regulations that can provide significant environmental impact reduction for minimal economic cost. In addition regulators need forecasts of future E&P trends to estimate the impact of future regulations. To determine future activity we attempted to survey potential operators when this approach was unsuccessful we created two econometric models of north and south Louisiana relating drilling activity, success ratio, and price to predict future wetland activity. Results of the econometric models indicate that environmental regulations have a small but statistically significant effect on drilling operations in wetland areas of Louisiana. We examined current wetland practices and evaluated those practices comparing environmental versus economic costs and created a method for ranking the practices.

  19. Constraint programming and decision making

    CERN Document Server

    Kreinovich, Vladik


    In many application areas, it is necessary to make effective decisions under constraints. Several area-specific techniques are known for such decision problems; however, because these techniques are area-specific, it is not easy to apply each technique to other applications areas. Cross-fertilization between different application areas is one of the main objectives of the annual International Workshops on Constraint Programming and Decision Making. Those workshops, held in the US (El Paso, Texas), in Europe (Lyon, France), and in Asia (Novosibirsk, Russia), from 2008 to 2012, have attracted researchers and practitioners from all over the world. This volume presents extended versions of selected papers from those workshops. These papers deal with all stages of decision making under constraints: (1) formulating the problem of multi-criteria decision making in precise terms, (2) determining when the corresponding decision problem is algorithmically solvable; (3) finding the corresponding algorithms, and making...

  20. Reservoir description and development of a mature oil field

    Energy Technology Data Exchange (ETDEWEB)

    Demiral, B.; Gumrah, F.; Okandan, E.


    The Mishovdag oil field is located in the southwest of Baku, Azerbaijan. The sandstone reservoirs consisting of five middle Pliocene age Horizons I, II, III, IV, and XII provide 40% of total oil production from the Sirvan oil field region. The reservoir trap is an anticline, and its size is approximately 15 x 5 km. Since its discovery in 1956, 516 wells had been drilled and 198 of them are still producing from successive layers of sandstone formations. This study was conducted to describe Horizon I of Block-9, prepare input data for a modeling study, and suggest development scenarios for this block. From this point of view, it was aimed to properly describe the reservoir properties with the use of core and, mainly, well log data. In this respect, these data set were evaluated to define the reservoir. According to field reports, seven producing layers were present in Horizon I of Block-9. From the results of further analysis on well logs, it was recognized that the reported seven layers were not continuous within Block-9 so, for modeling studies, these sandstone layers could be grouped under three main sand layers, namely, S1, S2, and S3, that were separated by two clay zones. The results of the modeling study showed that oil production was mainly from level S3 and level S1 was less swept by water injection. The oil saturation distribution at three levels at the end of 39 years of production indicated that there was still recoverable oil in levels S1 and S2. No free gas could be observed in any of the levels because the pressure maintenance provided by water injection caused free gas to redissolve in oil. (author)

  1. Aggregating energy flexibilities under constraints

    DEFF Research Database (Denmark)

    Valsomatzis, Emmanouil; Pedersen, Torben Bach; Abello, Alberto


    The flexibility of individual energy prosumers (producers and/or consumers) has drawn a lot of attention in recent years. Aggregation of such flexibilities provides prosumers with the opportunity to directly participate in the energy market and at the same time reduces the complexity of scheduling...... and amount dimensions. We define the problem of aggregating FOs taking into account grid power constraints. We also propose two constraint-based aggregation techniques that efficiently aggregate FOs while retaining flexibility. We show through a comprehensive evaluation that our techniques, in contrast...

  2. An index of reservoir habitat impairment (United States)

    Miranda, L.E.; Hunt, K.M.


    Fish habitat impairment resulting from natural and anthropogenic watershed and in-lake processes has in many cases reduced the ability of reservoirs to sustain native fish assemblages and fisheries quality. Rehabilitation of impaired reservoirs is hindered by the lack of a method suitable for scoring impairment status. To address this limitation, an index of reservoir habitat impairment (IRHI) was developed by merging 14 metrics descriptive of common impairment sources, with each metric scored from 0 (no impairment) to 5 (high impairment) by fisheries scientists with local knowledge. With a plausible range of 5 to 25, distribution of the IRHI scores ranged from 5 to 23 over 482 randomly selected reservoirs dispersed throughout the USA. The IRHI reflected five impairment factors including siltation, structural habitat, eutrophication, water regime, and aquatic plants. The factors were weakly related to key reservoir characteristics including reservoir area, depth, age, and usetype, suggesting that common reservoir descriptors are poor predictors of fish habitat impairment. The IRHI is rapid and inexpensive to calculate, provides an easily understood measure of the overall habitat impairment, allows comparison of reservoirs and therefore prioritization of restoration activities, and may be used to track restoration progress. The major limitation of the IRHI is its reliance on unstandardized professional judgment rather than standardized empirical measurements. ?? 2010 US Government.

  3. Water resources review: Wheeler Reservoir, 1990

    Energy Technology Data Exchange (ETDEWEB)

    Wallus, R.; Cox, J.P.


    Protection and enhancement of water quality is essential for attaining the full complement of beneficial uses of TVA reservoirs. The responsibility for improving and protecting TVA reservoir water quality is shared by various federal, state, and local agencies, as well as the thousands of corporations and property owners whose individual decisions affect water quality. TVA's role in this shared responsibility includes collecting and evaluating water resources data, disseminating water resources information, and acting as a catalyst to bring together agencies and individuals that have a responsibility or vested interest in correcting problems that have been identified. This report is one in a series of status reports that will be prepared for each of TVA's reservoirs. The purpose of this status report is to provide an up-to-date overview of the characteristics and conditions of Wheeler Reservoir, including: reservoir purposes and operation; physical characteristics of the reservoir and the watershed; water quality conditions: aquatic biological conditions: designated, actual, and potential uses of the reservoir and impairments of those uses; ongoing or planned reservoir management activities. Information and data presented here are form the most recent reports, publications, and original data available. 21 refs., 8 figs., 29 tabs.

  4. Time-lapse seismic within reservoir engineering

    NARCIS (Netherlands)

    Oldenziel, T.


    Time-lapse 3D seismic is a fairly new technology allowing dynamic reservoir characterisation in a true volumetric sense. By investigating the differences between multiple seismic surveys, valuable information about changes in the oil/gas reservoir state can be captured. Its interpretation involves

  5. Monitoring programme of water reservoir Grliste

    International Nuclear Information System (INIS)

    Vuckovic, M; Milenkovic, P.; Lukic, D.


    The quality of surface waters is a very important problem incorporated in the environment protection, especially in water resources. The Timok border-land hasn't got sufficient underground and surface waters. This is certificated by the International Association for Water Resource. That was reason for building the water reservoir 'Grliste'. Drinking water from water reservoir 'Grliste' supplies Zajecar and the surroundings. (author)

  6. 49 CFR 393.50 - Reservoirs required. (United States)


    ... depressing the brake pedal or treadle valve to the limit of its travel. (c) Safeguarding of air and vacuum... NECESSARY FOR SAFE OPERATION Brakes § 393.50 Reservoirs required. (a) Reservoir capacity for air-braked... driver to make a full service brake application with the engine stopped without depleting the air...

  7. Geothermal reservoir insurance study. Final report

    Energy Technology Data Exchange (ETDEWEB)


    The principal goal of this study was to provide analysis of and recommendations on the need for and feasibility of a geothermal reservoir insurance program. Five major tasks are reported: perception of risk by major market sectors, status of private sector insurance programs, analysis of reservoir risks, alternative government roles, and recommendations.

  8. Electromagnetic Heating Methods for Heavy Oil Reservoirs

    International Nuclear Information System (INIS)

    Sahni, A.; Kumar, M.; Knapp, R.B.


    The most widely used method of thermal oil recovery is by injecting steam into the reservoir. A well-designed steam injection project is very efficient in recovering oil, however its applicability is limited in many situations. Simulation studies and field experience has shown that for low injectivity reservoirs, small thickness of the oil-bearing zone, and reservoir heterogeneity limits the performance of steam injection. This paper discusses alternative methods of transferring heat to heavy oil reservoirs, based on electromagnetic energy. They present a detailed analysis of low frequency electric resistive (ohmic) heating and higher frequency electromagnetic heating (radio and microwave frequency). They show the applicability of electromagnetic heating in two example reservoirs. The first reservoir model has thin sand zones separated by impermeable shale layers, and very viscous oil. They model preheating the reservoir with low frequency current using two horizontal electrodes, before injecting steam. The second reservoir model has very low permeability and moderately viscous oil. In this case they use a high frequency microwave antenna located near the producing well as the heat source. Simulation results presented in this paper show that in some cases, electromagnetic heating may be a good alternative to steam injection or maybe used in combination with steam to improve heavy oil production. They identify the parameters which are critical in electromagnetic heating. They also discuss past field applications of electromagnetic heating including technical challenges and limitations

  9. Ichthyofauna of the reservoirs of Central Vietnam

    Directory of Open Access Journals (Sweden)

    I. A. Stolbunov


    Full Text Available Species composition, distribution and abundance of fish in the pelagic and littoral zone of four reservoirs of Central Vietnam (Suoi Chau, Kam Lam, Da Ban and Suoi Dau were studied first. According to the research data the fish community of the reservoirs is represented by 43 species of 19 fish families.

  10. Zooplankton of the Zaporiz’ke Reservoir

    Directory of Open Access Journals (Sweden)

    T. V. Mykolaichuk


    Full Text Available The paper is devoted to zooplankton species composition in the Zaporiz’ke Reservoir. The greatest species diversity was found in the macrophyte communities of the upper reservoir’s littoral, but the least zooplankton diversity – in the pelagic zone of the lower reservoir.

  11. Carbon emission from global hydroelectric reservoirs revisited. (United States)

    Li, Siyue; Zhang, Quanfa


    Substantial greenhouse gas (GHG) emissions from hydropower reservoirs have been of great concerns recently, yet the significant carbon emitters of drawdown area and reservoir downstream (including spillways and turbines as well as river reaches below dams) have not been included in global carbon budget. Here, we revisit GHG emission from hydropower reservoirs by considering reservoir surface area, drawdown zone and reservoir downstream. Our estimates demonstrate around 301.3 Tg carbon dioxide (CO2)/year and 18.7 Tg methane (CH4)/year from global hydroelectric reservoirs, which are much higher than recent observations. The sum of drawdown and downstream emission, which is generally overlooked, represents 42 % CO2 and 67 % CH4 of the total emissions from hydropower reservoirs. Accordingly, the global average emissions from hydropower are estimated to be 92 g CO2/kWh and 5.7 g CH4/kWh. Nonetheless, global hydroelectricity could currently reduce approximate 2,351 Tg CO2eq/year with respect to fuel fossil plant alternative. The new findings show a substantial revision of carbon emission from the global hydropower reservoirs.

  12. Incorporating EM Inversion into Reservoir Monitoring

    NARCIS (Netherlands)

    Wirianto, M.; Mulder, W.A.; Slob, E.C.


    In the application of controlled source electromagnetics for reservoir monitoring on land, the timelapse signal measured with a surface-to-surface acquisition can reveal the lateral extent on the surface of resistivity changes at depth in a hydrocarbon reservoir under production. However, a direct

  13. Multiscale ensemble filtering for reservoir engineering applications

    NARCIS (Netherlands)

    Lawniczak, W.; Hanea, R.G.; Heemink, A.; McLaughlin, D.


    Reservoir management requires periodic updates of the simulation models using the production data available over time. Traditionally, validation of reservoir models with production data is done using a history matching process. Uncertainties in the data, as well as in the model, lead to a nonunique

  14. Optimization of Multiple and Multipurpose Reservoir System Operations by Using Matrix Structure (Case Study: Karun and Dez Reservoir Dams.

    Directory of Open Access Journals (Sweden)

    Mohammad Heydari

    Full Text Available Optimal operation of water resources in multiple and multipurpose reservoirs is very complicated. This is because of the number of dams, each dam's location (Series and parallel, conflict in objectives and the stochastic nature of the inflow of water in the system. In this paper, performance optimization of the system of Karun and Dez reservoir dams have been studied and investigated with the purposes of hydroelectric energy generation and providing water demand in 6 dams. On the Karun River, 5 dams have been built in the series arrangements, and the Dez dam has been built parallel to those 5 dams. One of the main achievements in this research is the implementation of the structure of production of hydroelectric energy as a function of matrix in MATLAB software. The results show that the role of objective function structure for generating hydroelectric energy in weighting method algorithm is more important than water supply. Nonetheless by implementing ε- constraint method algorithm, we can both increase hydroelectric power generation and supply around 85% of agricultural and industrial demands.

  15. Optimization of Multiple and Multipurpose Reservoir System Operations by Using Matrix Structure (Case Study: Karun and Dez Reservoir Dams). (United States)

    Heydari, Mohammad; Othman, Faridah; Taghieh, Mahmood


    Optimal operation of water resources in multiple and multipurpose reservoirs is very complicated. This is because of the number of dams, each dam's location (Series and parallel), conflict in objectives and the stochastic nature of the inflow of water in the system. In this paper, performance optimization of the system of Karun and Dez reservoir dams have been studied and investigated with the purposes of hydroelectric energy generation and providing water demand in 6 dams. On the Karun River, 5 dams have been built in the series arrangements, and the Dez dam has been built parallel to those 5 dams. One of the main achievements in this research is the implementation of the structure of production of hydroelectric energy as a function of matrix in MATLAB software. The results show that the role of objective function structure for generating hydroelectric energy in weighting method algorithm is more important than water supply. Nonetheless by implementing ε- constraint method algorithm, we can both increase hydroelectric power generation and supply around 85% of agricultural and industrial demands.

  16. Quantification of Interbasin Transfers into the Addicks Reservoir during Hurricane Harvey (United States)

    Sebastian, A.; Juan, A.; Gori, A.; Maulsby, F.; Bedient, P. B.


    Between August 25 and 30, Hurricane Harvey dropped unprecedented rainfall over southeast Texas causing widespread flooding in the City of Houston. Water levels in the Addicks and Barker reservoirs, built in the 1940s to protect downtown Houston, exceeded previous records by approximately 2 meters. Concerns regarding structural integrity of the dams and damage to neighbourhoods in within the reservoir pool resulted in controlled releases into Buffalo Bayou, flooding an estimated 4,000 additional structures downstream of the dams. In 2016, during the Tax Day it became apparent that overflows from Cypress Creek in northern Harris County substantially contribute to water levels in Addicks. Prior to this event, little was known about the hydrodynamics of this overflow area or about the additional stress placed on Addicks and Barker reservoirs due to the volume of overflow. However, this information is critical for determining flood risk in Addicks Watershed, and ultimately Buffalo Bayou. In this study, we utilize the recently developed HEC-RAS 2D model the interbasin transfer that occurs between Cypress Creek Watershed and Addicks Reservoir to quantify the volume and rate at which water from Cypress enters the reservoir during extreme events. Ultimately, the results of this study will help inform the official hydrologic models used by HCFCD to determine reservoir operation during future storm events and better inform residents living in or above the reservoir pool about their potential flood risk.

  17. Monitoring small reservoirs' storage with satellite remote sensing in inaccessible areas (United States)

    Avisse, Nicolas; Tilmant, Amaury; François Müller, Marc; Zhang, Hua


    In river basins with water storage facilities, the availability of regularly updated information on reservoir level and capacity is of paramount importance for the effective management of those systems. However, for the vast majority of reservoirs around the world, storage levels are either not measured or not readily available due to financial, political, or legal considerations. This paper proposes a novel approach using Landsat imagery and digital elevation models (DEMs) to retrieve information on storage variations in any inaccessible region. Unlike existing approaches, the method does not require any in situ measurement and is appropriate for monitoring small, and often undocumented, irrigation reservoirs. It consists of three recovery steps: (i) a 2-D dynamic classification of Landsat spectral band information to quantify the surface area of water, (ii) a statistical correction of DEM data to characterize the topography of each reservoir, and (iii) a 3-D reconstruction algorithm to correct for clouds and Landsat 7 Scan Line Corrector failure. The method is applied to quantify reservoir storage in the Yarmouk basin in southern Syria, where ground monitoring is impeded by the ongoing civil war. It is validated against available in situ measurements in neighbouring Jordanian reservoirs. Coefficients of determination range from 0.69 to 0.84, and the normalized root-mean-square error from 10 to 16 % for storage estimations on six Jordanian reservoirs with maximal water surface areas ranging from 0.59 to 3.79 km2.

  18. Calibration of Seismic Attributes for Reservoir Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Wayne D. Pennington


    The project, "Calibration of Seismic Attributes for Reservoir Characterization," is now complete. Our original proposed scope of work included detailed analysis of seismic and other data from two to three hydrocarbon fields; we have analyzed data from four fields at this level of detail, two additional fields with less detail, and one other 2D seismic line used for experimentation. We also included time-lapse seismic data with ocean-bottom cable recordings in addition to the originally proposed static field data. A large number of publications and presentations have resulted from this work, inlcuding several that are in final stages of preparation or printing; one of these is a chapter on "Reservoir Geophysics" for the new Petroleum Engineering Handbook from the Society of Petroleum Engineers. Major results from this project include a new approach to evaluating seismic attributes in time-lapse monitoring studies, evaluation of pitfalls in the use of point-based measurements and facies classifications, novel applications of inversion results, improved methods of tying seismic data to the wellbore, and a comparison of methods used to detect pressure compartments. Some of the data sets used are in the public domain, allowing other investigators to test our techniques or to improve upon them using the same data. From the public-domain Stratton data set we have demonstrated that an apparent correlation between attributes derived along 'phantom' horizons are artifacts of isopach changes; only if the interpreter understands that the interpretation is based on this correlation with bed thickening or thinning, can reliable interpretations of channel horizons and facies be made. From the public-domain Boonsville data set we developed techniques to use conventional seismic attributes, including seismic facies generated under various neural network procedures, to subdivide regional facies determined from logs into productive and non-productive subfacies, and we


    Energy Technology Data Exchange (ETDEWEB)

    Wayne D. Pennington; Horacio Acevedo; Aaron Green; Joshua Haataja; Shawn Len; Anastasia Minaeva; Deyi Xie


    The project, ''Calibration of Seismic Attributes for Reservoir Calibration,'' is now complete. Our original proposed scope of work included detailed analysis of seismic and other data from two to three hydrocarbon fields; we have analyzed data from four fields at this level of detail, two additional fields with less detail, and one other 2D seismic line used for experimentation. We also included time-lapse seismic data with ocean-bottom cable recordings in addition to the originally proposed static field data. A large number of publications and presentations have resulted from this work, including several that are in final stages of preparation or printing; one of these is a chapter on ''Reservoir Geophysics'' for the new Petroleum Engineering Handbook from the Society of Petroleum Engineers. Major results from this project include a new approach to evaluating seismic attributes in time-lapse monitoring studies, evaluation of pitfalls in the use of point-based measurements and facies classifications, novel applications of inversion results, improved methods of tying seismic data to the wellbore, and a comparison of methods used to detect pressure compartments. Some of the data sets used are in the public domain, allowing other investigators to test our techniques or to improve upon them using the same data. From the public-domain Stratton data set we have demonstrated that an apparent correlation between attributes derived along ''phantom'' horizons are artifacts of isopach changes; only if the interpreter understands that the interpretation is based on this correlation with bed thickening or thinning, can reliable interpretations of channel horizons and facies be made. From the public-domain Boonsville data set we developed techniques to use conventional seismic attributes, including seismic facies generated under various neural network procedures, to subdivide regional facies determined from logs into

  20. A remote sensing method for estimating regional reservoir area and evaporative loss (United States)

    Zhang, Hua; Gorelick, Steven M.; Zimba, Paul V.; Zhang, Xiaodong


    Evaporation from the water surface of a reservoir can significantly affect its function of ensuring the availability and temporal stability of water supply. Current estimations of reservoir evaporative loss are dependent on water area derived from a reservoir storage-area curve. Such curves are unavailable if the reservoir is located in a data-sparse region or questionable if long-term sedimentation has changed the original elevation-area relationship. We propose a remote sensing framework to estimate reservoir evaporative loss at the regional scale. This framework uses a multispectral water index to extract reservoir area from Landsat imagery and estimate monthly evaporation volume based on pan-derived evaporative rates. The optimal index threshold is determined based on local observations and extended to unobserved locations and periods. Built on the cloud computing capacity of the Google Earth Engine, this framework can efficiently analyze satellite images at large spatiotemporal scales, where such analysis is infeasible with a single computer. Our study involves 200 major reservoirs in Texas, captured in 17,811 Landsat images over a 32-year period. The results show that these reservoirs contribute to an annual evaporative loss of 8.0 billion cubic meters, equivalent to 20% of their total active storage or 53% of total annual water use in Texas. At five coastal basins, reservoir evaporative losses exceed the minimum freshwater inflows required to sustain ecosystem health and fishery productivity of the receiving estuaries. Reservoir evaporative loss can be significant enough to counterbalance the positive effects of impounding water and to offset the contribution of water conservation and reuse practices. Our results also reveal the spatially variable performance of the multispectral water index and indicate the limitation of using scene-level cloud cover to screen satellite images. This study demonstrates the advantage of combining satellite remote sensing and

  1. Duck Valley Reservoirs Fish Stocking and Operation and Maintenance, 2005-2006 Annual Progress Report.

    Energy Technology Data Exchange (ETDEWEB)

    Sellman, Jake; Dykstra, Tim [Shoshone-Paiute Tribes


    The Duck Valley Reservoirs Fish Stocking and Operations and Maintenance (DV Fisheries) project is an ongoing resident fish program designed to enhance both subsistence fishing, educational opportunities for Tribal members of the Shoshone-Paiute Tribes, and recreational fishing facilities for non-Tribal members. In addition to stocking rainbow trout (Oncorhynchus mykiss) in Mountain View, Lake Billy Shaw, and Sheep Creek Reservoirs, the program also intends to afford and maintain healthy aquatic conditions for fish growth and survival, to provide superior facilities with wilderness qualities to attract non-Tribal angler use, and to offer clear, consistent communication with the Tribal community about this project as well as outreach and education within the region and the local community. Tasks for this performance period are divided into operations and maintenance plus monitoring and evaluation. Operation and maintenance of the three reservoirs include fences, roads, dams and all reservoir structures, feeder canals, water troughs and stock ponds, educational signs, vehicles and equipment, and outhouses. Monitoring and evaluation activities included creel, gillnet, wildlife, and bird surveys, water quality and reservoir structures monitoring, native vegetation planting, photo point documentation, control of encroaching exotic vegetation, and community outreach and education. The three reservoirs are monitored in terms of water quality and fishery success. Sheep Creek Reservoir was the least productive as a result of high turbidity levels and constraining water quality parameters. Lake Billy Shaw trout were in poorer condition than in previous years potentially as a result of water quality or other factors. Mountain View Reservoir trout exhibit the best health of the three reservoirs and was the only reservoir to receive constant flows of water.

  2. The freshwater reservoir effect in radiocarbon dating

    DEFF Research Database (Denmark)

    Philippsen, Bente


    effect on radiocarbon dating in an estuarine environment is examined. Here, freshwater influence causes reservoir ages to vary between 250 and 700 14C years during the period 5400 BC - AD 700. The examples in this study show clearly that the freshwater reservoir effect can seriously corrupt radiocarbon......The freshwater reservoir effect can result in anomalously old radiocarbon ages of samples from lakes and rivers. This includes the bones of people whose subsistence was based on freshwater fish, and pottery in which fish was cooked. Water rich in dissolved ancient calcium carbonates, commonly known...... as hard water, is the most common reason for the freshwater reservoir effect. It is therefore also called hardwater effect. Although it has been known for more than 60 years, it is still less well-recognized by archaeologists than the marine reservoir effect. The aim of this study is to examine the order...

  3. IAEA '77: between politics and factual constraints

    International Nuclear Information System (INIS)

    Freytag, A.


    The IAEA's organization of its 20th General Conference at Rio de Janeiro clearly underlined the importance of a comprehensive international transfer of nuclear technology. Despite all efforts to keep the Agency out of general political confrontations, the Conference was tinged politically by the PLO and South Africa problems. Besides the next five year program, which was agreed upon in the light of existing factual constraints, the support and control functions of the IAEA and next year's Salzburg Fuel Cycle Conference were other main topics of discussion. The 1977 IAEA budget was approved at a level of 43.5 million, the General Fund at 6.5 million. (orig.) [de

  4. EWPD Constraints on Flavor Symmetric Vector Fields

    CERN Document Server

    Grinstein, Benjamín; Trott, Michael


    Electroweak precision data constraints on flavor symmetric vector fields are determined. The flavor multiplets of spin one that we examine are the complete set of fields that couple to quark bi-linears at tree level while not initially breaking the quark global flavor symmetry group. Flavor safe vector masses proximate to, and in some cases below, the electroweak symmetry breaking scale are found to be allowed. Many of these fields provide a flavor safe mechanism to explain the t tbar forward backward anomaly, and can simultaneously significantly raise the allowed values of the Standard Model Higgs mass consistent with electroweak precision data.

  5. Some practical aspects of reservoir management

    Energy Technology Data Exchange (ETDEWEB)

    Fowler, M.L.; Young, M.A.; Cole, E.L.; Madden, M.P. [BDM-Oklahoma, Bartlesville, OK (United States)


    The practical essence of reservoir management is the optimal application of available resources-people, equipment, technology, and money to maximize profitability and recovery. Success must include knowledge and consideration of (1) the reservoir system, (2) the technologies available, and (3) the reservoir management business environment. Two Reservoir Management Demonstration projects (one in a small, newly-discovered field and one in a large, mature water-flood) implemented by the Department of Energy through BDM-Oklahoma illustrate the diversity of situations suited for reservoir management efforts. Project teams made up of experienced engineers, geoscientists, and other professionals arrived at an overall reservoir management strategy for each field. in 1993, Belden & Blake Corporation discovered a regionally significant oil reservoir (East Randolph Field) in the Cambrian Rose Run formation in Portage County, Ohio. Project objectives are to improve field operational economics and optimize oil recovery. The team focused on characterizing the reservoir geology and analyzing primary production and reservoir data to develop simulation models. Historical performance was simulated and predictions were made to assess infill drilling, water flooding, and gas repressurization. The Citronelle Field, discovered in 1955 in Mobile County, Alabama, has produced 160 million barrels from fluvial sandstones of the Cretaceous Rodessa formation. Project objectives are to address improving recovery through waterflood optimization and problems related to drilling, recompletions, production operations, and regulatory and environmental issues. Initial efforts focused on defining specific problems and on defining a geographic area within the field where solutions might best be pursued. Geologic and reservoir models were used to evaluate past performance and to investigate improved recovery operations.

  6. Reservoir Identification: Parameter Characterization or Feature Classification (United States)

    Cao, J.


    The ultimate goal of oil and gas exploration is to find the oil or gas reservoirs with industrial mining value. Therefore, the core task of modern oil and gas exploration is to identify oil or gas reservoirs on the seismic profiles. Traditionally, the reservoir is identify by seismic inversion of a series of physical parameters such as porosity, saturation, permeability, formation pressure, and so on. Due to the heterogeneity of the geological medium, the approximation of the inversion model and the incompleteness and noisy of the data, the inversion results are highly uncertain and must be calibrated or corrected with well data. In areas where there are few wells or no well, reservoir identification based on seismic inversion is high-risk. Reservoir identification is essentially a classification issue. In the identification process, the underground rocks are divided into reservoirs with industrial mining value and host rocks with non-industrial mining value. In addition to the traditional physical parameters classification, the classification may be achieved using one or a few comprehensive features. By introducing the concept of seismic-print, we have developed a new reservoir identification method based on seismic-print analysis. Furthermore, we explore the possibility to use deep leaning to discover the seismic-print characteristics of oil and gas reservoirs. Preliminary experiments have shown that the deep learning of seismic data could distinguish gas reservoirs from host rocks. The combination of both seismic-print analysis and seismic deep learning is expected to be a more robust reservoir identification method. The work was supported by NSFC under grant No. 41430323 and No. U1562219, and the National Key Research and Development Program under Grant No. 2016YFC0601

  7. Assessment of disturbance at three spatial scales in two large tropical reservoirs

    Directory of Open Access Journals (Sweden)

    Letícia de Morais


    Full Text Available Large reservoirs are an increasingly common feature across tropical landscapes because of their importance for water supply, flood control and hydropower, but their ecological conditions are infrequently evaluated. Our objective was to assess the range of disturbances for two large tropical reservoirs and their influences on benthic macroinvertebrates. We tested three hypotheses: i a wide variation in the level of environmental disturbance can be observed among sites in the reservoirs; ii the two reservoirs would exhibit a different degree of disturbance level; and iii the magnitude of disturbance would influence the structure and composition of benthic assemblages. For each reservoir, we assessed land use (macroscale, physical habitat structure (mesoscale, and water quality (microscale. We sampled 40 sites in the littoral zones of both Três Marias and São Simão Reservoirs (Minas Gerais, Brazil. At the macroscale, we measured cover percentages of land use categories in buffer areas at each site, where each buffer was a circular arc of 250 m. At the mesoscale, we assessed the presence of human disturbances in the riparian and drawdown zones at the local (site scale. At the microscale, we assessed water quality at each macroinvertebrate sampling station using the Micro Disturbance Index (MDI. To evaluate anthropogenic disturbance of each site, we calculated an integrated disturbance index (IDI from a buffer disturbance index (BDI and a local disturbance index (LDI. For each site, we calculated richness and abundance of benthic macroinvertebrates, Chironomidae genera richness, abundance and percent Chironomidae individuals, abundance and percent EPT individuals, richness and percent EPT taxa, abundance and percent resistant individuals, and abundance and percent non-native individuals. We also evaluated the influence of disturbance on benthic macroinvertebrate assemblages at the entire-reservoir scale. The BDI, LDI and IDI had significantly

  8. Dynamics and maintenance of bipartite entanglement via the Stark shift effect inside dissipative reservoirs (United States)

    Golkar, S.; Tavassoly, M. K.


    In this paper, the exact entanglement dynamics are obtained of two two-level atoms with two-photon transitions accompanied by the Stark shift, where each atom is independently coupled to a dissipative reservoir at zero temperature. The results show that, in the presence of Stark shift, entanglement can be preserved for a long time and the decoherence process of entanglement slows down. In particular, we find that while the Stark shift has a constructive effect on entanglement protection for both Markovian and non-Markovian reservoirs, this positive effect can be more visible in the non-Markovian reservoir even with low Stark shift parameter values.

  9. Simulation and optimisation modelling approach for operation of the Hoa Binh Reservoir, Vietnam

    DEFF Research Database (Denmark)

    Ngo, Long le; Madsen, Henrik; Rosbjerg, Dan


    . This paper proposes to optimise the control strategies for the Hoa Binh reservoir operation by applying a combination of simulation and optimisation models. The control strategies are set up in the MIKE 11 simulation model to guide the releases of the reservoir system according to the current storage level......, the hydro-meteorological conditions, and the time of the year. A heuristic global optimisation tool, the shuffled complex evolution (SCE) algorithm, is adopted for optimising the reservoir operation. The optimisation puts focus on the trade-off between flood control and hydropower generation for the Hoa...

  10. Correlation functions and susceptibilities of photonics band gap reservoirs

    International Nuclear Information System (INIS)

    Konopka, M.


    We investigate quantum statistical properties of photonic band gap reservoirs in terms of correlation functions and susceptibilities in time and spectral domains. Typical features are oscillations of the time-dependent correlation functions and susceptibilities. This is because photonic bad gap reservoirs are intrinsically non-Markovian reservoirs. The results help us to understand better how intrinsic quantum-statistical properties of a reservoir influence dynamics of an atom interacting with this reservoir. Boundary conditions influence time and spectral properties of the electromagnetic field. This well-known fact has a great importance in optics and generally in electromagnetism. Specific examples are resonators used in laser technique and cavity electrodynamics. In quantum optics high-Q micro cavities are used for single-atom experiments when an atom can interact in a coherent way with an electromagnetic field which has its mode structure totally different from those in free space. In particular, interaction of an (effectively) two-level atom with a single-mode cavity field was observed in the region of microwaves (with the wavelength about 1 cm). In 1987 Yablonovitch and John independently proposed that certain periodic dielectric structures can present forbidden frequency gaps (or pseudo gaps in partially disordered structures) for transverse modes. Such periodic structures were named 'photonic band structures' or 'photonic crystals', in analogy with electronic crystals which also have a (forbidden) gap for electronic energy. For true photonic crystals the basic property of blocking electromagnetic wave propagation must be fulfilled for all waves within some frequency range, i.e. for all wavevector and polarization directions

  11. Reservoir management under geological uncertainty using fast model update

    NARCIS (Netherlands)

    Hanea, R.; Evensen, G.; Hustoft, L.; Ek, T.; Chitu, A.; Wilschut, F.


    Statoil is implementing "Fast Model Update (FMU)," an integrated and automated workflow for reservoir modeling and characterization. FMU connects all steps and disciplines from seismic depth conversion to prediction and reservoir management taking into account relevant reservoir uncertainty. FMU

  12. Evaluation of Gaussian approximations for data assimilation in reservoir models

    KAUST Repository

    Iglesias, Marco A.


    The Bayesian framework is the standard approach for data assimilation in reservoir modeling. This framework involves characterizing the posterior distribution of geological parameters in terms of a given prior distribution and data from the reservoir dynamics, together with a forward model connecting the space of geological parameters to the data space. Since the posterior distribution quantifies the uncertainty in the geologic parameters of the reservoir, the characterization of the posterior is fundamental for the optimal management of reservoirs. Unfortunately, due to the large-scale highly nonlinear properties of standard reservoir models, characterizing the posterior is computationally prohibitive. Instead, more affordable ad hoc techniques, based on Gaussian approximations, are often used for characterizing the posterior distribution. Evaluating the performance of those Gaussian approximations is typically conducted by assessing their ability at reproducing the truth within the confidence interval provided by the ad hoc technique under consideration. This has the disadvantage of mixing up the approximation properties of the history matching algorithm employed with the information content of the particular observations used, making it hard to evaluate the effect of the ad hoc approximations alone. In this paper, we avoid this disadvantage by comparing the ad hoc techniques with a fully resolved state-of-the-art probing of the Bayesian posterior distribution. The ad hoc techniques whose performance we assess are based on (1) linearization around the maximum a posteriori estimate, (2) randomized maximum likelihood, and (3) ensemble Kalman filter-type methods. In order to fully resolve the posterior distribution, we implement a state-of-the art Markov chain Monte Carlo (MCMC) method that scales well with respect to the dimension of the parameter space, enabling us to study realistic forward models, in two space dimensions, at a high level of grid refinement. Our

  13. Comparison of Mercury in Water, Bottom Sediment, and Zooplankton in Two Front Range Reservoirs in Colorado, 2008-09 (United States)

    Mast, M. Alisa; Krabbenhoft, David P.


    concentrations in hypolimnetic water indicate low potential for increased methylmercury production following the development of anoxic conditions in summer. Based on the limited dataset, water-level fluctuations and shoreline characteristics appear to best explain differences in fish-tissue mercury concentrations between the reservoirs. Due to the shallow depth and the large annual water-level fluctuations at Brush Hollow Reservoir, proportionally larger areas of shoreline at Brush Hollow Reservoir are subjected to annual reflooding compared to Pueblo Reservoir. Moreover, presence of macrophyte beds and regrowth of terrestrial vegetation likely increase the organic content of near-shore sediments in Brush Hollow Reservoir, which may stimulate methylmercury production in littoral areas subject to reflooding. Results of a laboratory incubation experiment were consistent with this hypothesis.

  14. Sterile neutrino constraints from cosmology

    DEFF Research Database (Denmark)

    Hamann, Jan; Hannestad, Steen; Raffelt, Georg G.


    The presence of light particles beyond the standard model's three neutrino species can profoundly impact the physics of decoupling and primordial nucleosynthesis. I review the observational signatures of extra light species, present constraints from recent data, and discuss the implications of po...... of possible sterile neutrinos with O(eV)-masses for cosmology....

  15. Constraint Programming versus Mathematical Programming

    DEFF Research Database (Denmark)

    Hansen, Jesper


    Constraint Logic Programming (CLP) is a relatively new technique from the 80's with origins in Computer Science and Artificial Intelligence. Lately, much research have been focused on ways of using CLP within the paradigm of Operations Research (OR) and vice versa. The purpose of this paper...

  16. Conjoined Constraints and Phonological Acquisition

    Directory of Open Access Journals (Sweden)

    Giovana Bonilha


    Full Text Available Since the start of Optimality Theory (Prince & Smolensky, 1993, research on phonological acquisition has explored the explanatory potential of constraint theories. This study, also based on Optimality Theory, attempts to analyze the acquisition of CVVC syllable structure by Brazilian Portuguese children and addresses the issue of Local Conjunction (Smolensky, 1995, 1997 in research that deals with problems of phonological acquisition.

  17. Efficient Searching with Linear Constraints

    DEFF Research Database (Denmark)

    Agarwal, Pankaj K.; Arge, Lars Allan; Erickson, Jeff


    We show how to preprocess a set S of points in d into an external memory data structure that efficiently supports linear-constraint queries. Each query is in the form of a linear constraint xd a0+∑d−1i=1 aixi; the data structure must report all the points of S that satisfy the constraint....... This problem is called halfspace range searching in the computational geometry literature. Our goal is to minimize the number of disk blocks required to store the data structure and the number of disk accesses (I/Os) required to answer a query. For d=2, we present the first data structure that uses linear...... space and answers linear-constraint queries using an optimal number of I/Os in the worst case. For d=3, we present a near-linear-size data structure that answers queries using an optimal number of I/Os on the average. We present linear-size data structures that can answer d-dimensional linear...

  18. Financial Constraints: Explaining Your Position. (United States)

    Cargill, Jennifer


    Discusses the importance of educating library patrons about the library's finances and the impact of budget constraints and the escalating cost of serials on materials acquisition. Steps that can be taken in educating patrons by interpreting and publicizing financial information are suggested. (MES)

  19. Observational constraints on cluster evolution

    NARCIS (Netherlands)

    Larsen, S.S.


    Current observational constraints on the dynamical evolution of star clusters are reviewed. Theory and observations now agree nicely on the mass dependency and time scales for disruption of young star clusters in galactic disks, but many problems still await resolution. The origin of the mass

  20. Variability, Constraints, and Creativity: Shedding Light on Claude Monet. (United States)

    Stokes, Patricia D.


    Discusses how creative individuals maintain high levels of variability, examining how Claude Monet's habitually high level of variability in painting was acquired during his childhood and early apprenticeship and maintained throughout his adult career by a continuous series of task constraints imposed by the artist on his own work. For Monet,…

  1. Organic and weed control in water supply reservoirs of power plants

    International Nuclear Information System (INIS)

    Eswaran, M.S.


    Aquatic weeds and algal control in water supply reservoirs used for multipurpose use need specific attention, since they pose a lot of problem for the operating plants by affecting (a) the water quality of boiler and feed waters, (b) the performance of DM plants by reducing the efficiency of Anion beds, (c) the performance of Activated Carbon Filters (ACF) and (d) fouling induced corrosion problems in cooling water systems (Heat Exchangers and Piping materials) causing plant outages leading to production losses. The photosynthetic activity of planktonic plants which are growing abundantly in the open reservoir, sustained by the relatively high inorganic phosphate levels shoots up the pH of the reservoir water to very high levels. High pH, Total Dissolved Solids (TDS) and depleted plants can increase corrosion problems affecting plant performance. This paper focuses on the type of weeds prominent in the water supply reservoir at Kalpakkam and the associated problems in the Nuclear Power Plants (NPPs). (author)

  2. Top-Down, Intelligent Reservoir Model (United States)

    Mohaghegh, Shahab


    Conventional reservoir simulation and modeling is a bottom-up approach. It starts with building a geological model of the reservoir that is populated with the best available petrophysical and geophysical information at the time of development. Engineering fluid flow principles are added and solved numerically so as to arrive at a dynamic reservoir model. The dynamic reservoir model is calibrated using the production history of multiple wells and the history matched model is used to strategize field development in order to improve recovery. Top-Down, Intelligent Reservoir Modeling approaches the reservoir simulation and modeling from an opposite angle by attempting to build a realization of the reservoir starting with the measured well production behavior (history). The production history is augmented by core, log, well test and seismic data in order to increase the accuracy of the Top-Down modeling technique. Although not intended as a substitute for the conventional reservoir simulation of large, complex fields, this novel approach to reservoir modeling can be used as an alternative (at a fraction of the cost) to conventional reservoir simulation and modeling in cases where performing conventional modeling is cost (and man-power) prohibitive. In cases where a conventional model of a reservoir already exists, Top-Down modeling should be considered as a compliment to, rather than a competition for the conventional technique, to provide an independent look at the data coming from the reservoir/wells for optimum development strategy and recovery enhancement. Top-Down, Intelligent Reservoir Modeling starts with well-known reservoir engineering techniques such as Decline Curve Analysis, Type Curve Matching, History Matching using single well numerical reservoir simulation, Volumetric Reserve Estimation and calculation of Recovery Factors for all the wells (individually) in the field. Using statistical techniques multiple Production Indicators (3, 6, and 9 months cum

  3. An experimental unification of reservoir computing methods. (United States)

    Verstraeten, D; Schrauwen, B; D'Haene, M; Stroobandt, D


    Three different uses of a recurrent neural network (RNN) as a reservoir that is not trained but instead read out by a simple external classification layer have been described in the literature: Liquid State Machines (LSMs), Echo State Networks (ESNs) and the Backpropagation Decorrelation (BPDC) learning rule. Individual descriptions of these techniques exist, but a overview is still lacking. Here, we present a series of experimental results that compares all three implementations, and draw conclusions about the relation between a broad range of reservoir parameters and network dynamics, memory, node complexity and performance on a variety of benchmark tests with different characteristics. Next, we introduce a new measure for the reservoir dynamics based on Lyapunov exponents. Unlike previous measures in the literature, this measure is dependent on the dynamics of the reservoir in response to the inputs, and in the cases we tried, it indicates an optimal value for the global scaling of the weight matrix, irrespective of the standard measures. We also describe the Reservoir Computing Toolbox that was used for these experiments, which implements all the types of Reservoir Computing and allows the easy simulation of a wide range of reservoir topologies for a number of benchmarks.

  4. Stochastic Reservoir Characterization Constrained by Seismic Data

    Energy Technology Data Exchange (ETDEWEB)

    Eide, Alfhild Lien


    In order to predict future production of oil and gas from a petroleum reservoir, it is important to have a good description of the reservoir in terms of geometry and physical parameters. This description is used as input to large numerical models for the fluid flow in the reservoir. With increased quality of seismic data, it is becoming possible to extend their use from the study of large geologic structures such as seismic horizons to characterization of the properties of the reservoir between the horizons. Uncertainties because of the low resolution of seismic data can be successfully handled by means of stochastic modeling, and spatial statistics can provide tools for interpolation and simulation of reservoir properties not completely resolved by seismic data. This thesis deals with stochastic reservoir modeling conditioned to seismic data and well data. Part I presents a new model for stochastic reservoir characterization conditioned to seismic traces. Part II deals with stochastic simulation of high resolution impedance conditioned to measured impedance. Part III develops a new stochastic model for calcite cemented objects in a sandstone background; it is a superposition of a marked point model for the calcites and a continuous model for the background.

  5. Reflection Phenomena in Underground Pumped Storage Reservoirs

    Directory of Open Access Journals (Sweden)

    Elena Pummer


    Full Text Available Energy storage through hydropower leads to free surface water waves in the connected reservoirs. The reason for this is the movement of water between reservoirs at different elevations, which is necessary for electrical energy storage. Currently, the expansion of renewable energies requires the development of fast and flexible energy storage systems, of which classical pumped storage plants are the only technically proven and cost-effective technology and are the most used. Instead of classical pumped storage plants, where reservoirs are located on the surface, underground pumped storage plants with subsurface reservoirs could be an alternative. They are independent of topography and have a low surface area requirement. This can be a great advantage for energy storage expansion in case of environmental issues, residents’ concerns and an unusable terrain surface. However, the reservoirs of underground pumped storage plants differ in design from classical ones for stability and space reasons. The hydraulic design is essential to ensure their satisfactory hydraulic performance. The paper presents a hybrid model study, which is defined here as a combination of physical and numerical modelling to use the advantages and to compensate for the disadvantages of the respective methods. It shows the analysis of waves in ventilated underground reservoir systems with a great length to height ratio, considering new operational aspects from energy supply systems with a great percentage of renewable energies. The multifaceted and narrow design of the reservoirs leads to complex free surface flows; for example, undular and breaking bores arise. The results show excessive wave heights through wave reflections, caused by the impermeable reservoir boundaries. Hence, their knowledge is essential for a successful operational and constructive design of the reservoirs.

  6. Spatial and temporal variations in fish assemblage: testing the zonation concept in small reservoirs. (United States)

    Baumgartner, M T; Baumgartner, G; Gomes, L C


    Large reservoirs usually present spatial gradients in fish assemblage, distinguishing three strata (littoral, pelagic, and bathypelagic) along the vertical and horizontal axes, and three zones (fluvial, transitional, and lacustrine) along the longitudinal axis. The main objective of this study was to assess if small reservoirs also present the spatial gradients in fish assemblage attributes and structure as already observed in large reservoirs. Fish surveys were conducted quarterly, from 2003 to 2008, in the Mourão Reservoir (Mourão River, Paraná, Brazil), using gillnets with different mesh sizes, arranged in all strata of all three zones. Community attributes (species richness and evenness) were calculated for each sample, and differences were tested using three-way ANOVA (factors: zone, strata, year). Community composition was summarized using Correspondence Analysis (CA) and differences were tested with three-way ANOVA for each axis, controlling the same three factors. Because of the high variability in reservoir water level through time, all analyses were made considering temporal variations. Species richness presented a decreasing trend from fluvial to lacustrine zones, and higher values in littoral strata, possibly because upper reaches and littoral regions provide better conditions for fish to feed and to reproduce. Evenness was considerably low, presenting high variability, and no evident pattern. The expected longitudinal gradient was not found in this study indicating longitudinal similarity, contrary to observed in large reservoirs. Vertical and horizontal gradients were observed in all sampling stations, indicating that abiotic and biotic conditions are influencing fish distributions within the reservoir.

  7. Biofilm composition in the Olt River (Romania) reservoirs impacted by a chlor-alkali production plant. (United States)

    Dranguet, P; Cosio, C; Le Faucheur, S; Hug Peter, D; Loizeau, J-L; Ungureanu, V-Gh; Slaveykova, V I


    Freshwater biofilms can be useful indicators of water quality and offer the possibility to assess contaminant effects at the community level. The present field study examines the effects of chlor-alkali plant effluents on the community composition of biofilms grown in the Olt River (Romania) reservoirs. The relationship between ambient water quality variables and community composition alterations was explored. Amplicon sequencing revealed a significant modification of the composition of microalgal, bacterial and fungal communities in the biofilms collected in the impacted reservoirs in comparison with those living in the uncontaminated control reservoir. The abundance corrected Simpson index showed lower richness and diversity in biofilms collected in the impacted reservoirs than in the control reservoir. The biofilm bacterial communities of the impacted reservoirs were characterized by the contaminant-tolerant Cyanobacteria and Bacteroidetes, whereas microalgal communities were predominantly composed of Bacillariophyta and fungal communities of Lecanoromycetes and Paraglomycetes. A principal component analysis revealed that major contaminants present in the waste water of the chlor-alkali production plant, i.e. Na + , Ca 2+ , Cl - and Hg, were correlated with the alteration of biofilm community composition in the impacted reservoirs. However, the biofilm composition was also influenced by water quality variables such as NO 3 - , SO 4 2- , DOC and Zn from unknown sources. The results of the present study imply that, even when below the environmental quality standards, typical contaminants of chlor-alkali plant releases may affect biofilm composition and that their impacts on the microbial biodiversity might be currently overlooked.

  8. Managing Constraint Generators in Retail Design Processes

    DEFF Research Database (Denmark)

    Münster, Mia Borch; Haug, Anders

    case studies of fashion store design projects, the present paper addresses this gap. The and six case studies of fashion store design projects, the present paper sheds light on the types of constraints generated by the relevant constraint generators. The paper shows that in the cases studied......, the influence of the constraints generated by these constraint generators decreased during the design process except for supplier-generated constraints, which increased in the final stages of the design process. The paper argues that a thorough design preparation phase would be beneficial, and that constraints...

  9. Creativity from Constraints in Engineering Design

    DEFF Research Database (Denmark)

    Onarheim, Balder


    This paper investigates the role of constraints in limiting and enhancing creativity in engineering design. Based on a review of literature relating constraints to creativity, the paper presents a longitudinal participatory study from Coloplast A/S, a major international producer of disposable...... and ownership of formal constraints played a crucial role in defining their influence on creativity – along with the tacit constraints held by the designers. The designers were found to be highly constraint focused, and four main creative strategies for constraint manipulation were observed: blackboxing...

  10. The 12.4 ka Upper Apoyeque Tephra, Nicaragua: stratigraphy, dispersal, composition, magma reservoir conditions and trigger of the plinian eruption (United States)

    Wehrmann, Heidi; Freundt, Armin; Kutterolf, Steffen


    Upper Apoyeque Tephra (UAq) was formed by a rhyodacitic plinian eruption in west-central Nicaragua at 12.4 ka BP. The fallout tephra was dispersed from a progressively rising plinian eruption column that became exposed to different wind speeds and directions at different heights in the stratosphere, leading to an asymmetric tephra fan with different facies in the western and southern sector. Tephra dispersal data integrated with geochemical compositions of lava flows in the area facilitate delimitation of the source vent to the south of Chiltepe Peninsula. UAq, Lower Apoyeque Tephra, Apoyeque Ignimbrite, and two lava lithic clasts in San Isidro Tephra together form a differentiation trend distinct from that of the younger tephras and lavas at Chiltepe Volcanic Complex in a TiO2 versus K2O diagram, compositionally precluding a genetic relationship of UAq with the present-day Apoyeque stratovolcano. Apoyeque Volcano in its present shape did not exist at the time of the UAq eruption. The surface expression of the UAq vent is now obscured by younger eruption products and lake water. Pressure-temperature constraints based on mineral-melt equilibria and fluid inclusions in plagioclase indicate at least two magma storage levels. Clinopyroxenes crystallised in a deep crustal reservoir at ˜24 km depth as inferred from clinopyroxene-melt inclusion pairs. Chemical disequilibrium between clinopyroxenes and matrix glasses indicates rapid magma ascent to the shallower reservoir at ˜5.4 km depth, where magnesiohornblendes and plagioclase fractionated at a temperature of ˜830 °C. Water concentrations were ˜5.5 wt.% as derived from congruent results of amphibole and plagioclase-melt hygrometry. The eruption was triggered by injection of a hotter, more primitive melt into a water-supersaturated reservoir.

  11. Reservoir-induced landslides and risk control in Three Gorges Project on Yangtze River, China

    Directory of Open Access Journals (Sweden)

    Yueping Yin


    Full Text Available The Three Gorges region in China was basically a geohazard-prone area prior to construction of the Three Gorges Reservoir (TGR. After construction of the TGR, the water level was raised from 70 m to 175 m above sea level (ASL, and annual reservoir regulation has caused a 30-m water level difference after impoundment of the TGR since September 2008. This paper first presents the spatiotemporal distribution of landslides in six periods of 175 m ASL trial impoundments from 2008 to 2014. The results show that the number of landslides sharply decreased from 273 at the initial stage to less than ten at the second stage of impoundment. Based on this, the reservoir-induced landslides in the TGR region can be roughly classified into five failure patterns, i.e. accumulation landslide, dip-slope landslide, reversed bedding landslide, rockfall, and karst breccia landslide. The accumulation landslides and dip-slope landslides account for more than 90%. Taking the Shuping accumulation landslide (a sliding mass volume of 20.7 × 106 m3 in Zigui County and the Outang dip-slope landslide (a sliding mass volume of about 90 × 106 m3 in Fengjie County as two typical cases, the mechanisms of reactivation of the two landslides are analyzed. The monitoring data and factor of safety (FOS calculation show that the accumulation landslide is dominated by water level variation in the reservoir as most part of the mass body is under 175 m ASL, and the dip-slope landslide is controlled by the coupling effect of reservoir water level variation and precipitation as an extensive recharge area of rainfall from the rear and the front mass is below 175 m ASL. The characteristics of landslide-induced impulsive wave hazards after and before reservoir impoundment are studied, and the probability of occurrence of a landslide-induced impulsive wave hazard has increased in the reservoir region. Simulation results of the Ganjingzi landslide in Wushan County indicate the

  12. Estimating Water Levels with Google Earth Engine (United States)

    Lucero, E.; Russo, T. A.; Zentner, M.; May, J.; Nguy-Robertson, A. L.


    Reservoirs serve multiple functions and are vital for storage, electricity generation, and flood control. For many areas, traditional ground-based reservoir measurements may not be available or data dissemination may be problematic. Consistent monitoring of reservoir levels in data-poor areas can be achieved through remote sensing, providing information to researchers and the international community. Estimates of trends and relative reservoir volume can be used to identify water supply vulnerability, anticipate low power generation, and predict flood risk. Image processing with automated cloud computing provides opportunities to study multiple geographic areas in near real-time. We demonstrate the prediction capability of a cloud environment for identifying water trends at reservoirs in the US, and then apply the method to data-poor areas in North Korea, Iran, Azerbaijan, Zambia, and India. The Google Earth Engine cloud platform hosts remote sensing data and can be used to automate reservoir level estimation with multispectral imagery. We combine automated cloud-based analysis from Landsat image classification to identify reservoir surface area trends and radar altimetry to identify reservoir level trends. The study estimates water level trends using three years of data from four domestic reservoirs to validate the remote sensing method, and five foreign reservoirs to demonstrate the method application. We report correlations between ground-based reservoir level measurements in the US and our remote sensing methods, and correlations between the cloud analysis and altimetry data for reservoirs in data-poor areas. The availability of regular satellite imagery and an automated, near real-time application method provides the necessary datasets for further temporal analysis, reservoir modeling, and flood forecasting. All statements of fact, analysis, or opinion are those of the author and do not reflect the official policy or position of the Department of Defense or any

  13. The freshwater reservoir effect in radiocarbon dating

    DEFF Research Database (Denmark)

    Philippsen, Bente

    case studies will show the degree of variability of the freshwater reservoir effect over short and long timescales. Radiocarbon dating of recent water samples, aquatic plants and animals, shows that age differences of up to 2000 years can occur within one river. In the Limfjord, freshwater influence...... caused reservoir ages to vary between 250 and 700 years during the period 5400 BC - AD 700. Finally, I will discuss the implications of the freshwater reservoir effect for radiocarbon dating of Mesolithic pottery from inland sites of the Ertebølle culture in Northern Germany....

  14. Constraints, Trade-offs and the Currency of Fitness. (United States)

    Acerenza, Luis


    Understanding evolutionary trajectories remains a difficult task. This is because natural evolutionary processes are simultaneously affected by various types of constraints acting at the different levels of biological organization. Of particular importance are constraints where correlated changes occur in opposite directions, called trade-offs. Here we review and classify the main evolutionary constraints and trade-offs, operating at all levels of trait hierarchy. Special attention is given to life history trade-offs and the conflict between the survival and reproduction components of fitness. Cellular mechanisms underlying fitness trade-offs are described. At the metabolic level, a linear trade-off between growth and flux variability was found, employing bacterial genome-scale metabolic reconstructions. Its analysis indicates that flux variability can be considered as the currency of fitness. This currency is used for fitness transfer between fitness components during adaptations. Finally, a discussion is made regarding the constraints which limit the increase in the amount of fitness currency during evolution, suggesting that occupancy constraints are probably the main restrictions.

  15. Constraints Faced by Stakeholders under Agriculture Technology Management Agency (ATMA

    Directory of Open Access Journals (Sweden)

    J. Yoga Narasimhalu Naidu


    Full Text Available Agriculture Technology Management Agency (ATMA is a registered society in India with key stakeholders enmeshed with various agricultural activities for sustainable agricultural development in the state, with focus at district level. It is a hotbed for integrating research, extension and marketing activities and decentralizing day-to-day management of the public Agricultural Technology Development and Dissemination System. The present study was carried out in Andhra Pradesh state to explore the constraints faced by the extension functionaries at each level of decentralized management. Moreover, constraints perceived by the farmers with the support of ATMA in realizing their needs were also studied.

  16. Shifting relative importance of climatic constraints on land surface phenology (United States)

    Garonna, Irene; de Jong, Rogier; Stöckli, Reto; Schmid, Bernhard; Schenkel, David; Schimel, David; Schaepman, Michael E.


    Land surface phenology (LSP), the study of seasonal dynamics of vegetated land surfaces from remote sensing, is a key indicator of global change, that both responds to and influences weather and climate. The effects of climatic changes on LSP depend on the relative importance of climatic constraints in specific regions—which are not well understood at global scale. Understanding the climatic constraints that underlie LSP is crucial for explaining climate change effects on global vegetation phenology. We used a combination of modelled and remotely-sensed vegetation activity records to quantify the interplay of three climatic constraints on land surface phenology (namely minimum temperature, moisture availability, and photoperiod), as well as the dynamic nature of these constraints. Our study examined trends and the relative importance of the three constrains at the start and the end of the growing season over eight global environmental zones, for the past three decades. Our analysis revealed widespread shifts in the relative importance of climatic constraints in the temperate and boreal biomes during the 1982-2011 period. These changes in the relative importance of the three climatic constraints, which ranged up to 8% since 1982 levels, varied with latitude and between start and end of the growing season. We found a reduced influence of minimum temperature on start and end of season in all environmental zones considered, with a biome-dependent effect on moisture and photoperiod constraints. For the end of season, we report that the influence of moisture has on average increased for both the temperate and boreal biomes over 8.99 million km2. A shifting relative importance of climatic constraints on LSP has implications both for understanding changes and for improving how they may be modelled at large scales.

  17. Optimization of the Infrastructure of Reinforced Concrete Reservoirs by a Particle Swarm Algorithm

    Directory of Open Access Journals (Sweden)

    Kia Saeed