381 research outputs found
Sucker Rumination: How Aversive Self-Directed Cognitions Affect Purchase Intentions
If there is a silver lining to having been tricked in an economic context, perhaps it is that one can be wiser for the experience. Presumably, people are able to learn from such transactions and avoid them in the future. The current study employed an experimental design in which some participants were assigned to a control condition and others were told that they had recently been duped. Results indicated that among those who felt duped, people high in sucker rumination were subsequently less likely to avoid the source of deception. That is, people with a tendency to blame themselves harshly for being duped were the least likely to be wiser for the experience. For people high in sucker rumination, there is a great deal of psychic discomfort in getting duped, but no silver lining of being wiser
Population Suppression of Western Corn Rootworm by Adult Control with ULV Malathion
ULV malathion (9.7 oz AI/acre) was applied by air to a 16 square-mile area during August of 1968, 1969, and 1970. Adult Diabrotica virgifera LeConte populations were reduced the following season by 39, 54, and 72%. No economic infestations occurred in the treated area the year following any application. Postspray migration of beetles was very limited, but adult migration during the peak emergence period the following season contributed to repopulation of the treated area. Migration and fecundity appear to be density-dependent factors which favor increases under low populations. Area suppression does not appear economically feasible, but adult control in individual fields may be an acceptable alternative to soil insecticides applied for larval control. A model was developed for timing treatments against adults; treatments between Aug. 1–15 should result in adequate population suppression to prevent damage the following season. Mid-August population levels of 1.0 beetle/ plant were an acceptable economic threshold for determining the need for control measures
Molecular Differentiation of Alfalfa Weevil Strains (Coleoptera: Curculionidae)
Mitochondrial DNA was amplified and sequenced from eastern, western, and Egyptian strains of alfalfa weevil, Hypera postica (Gyllenhal). Eastern and Egyptian weevils differed at only 2 nucleotide sites in 1,031 base pairs sequenced; western weevils differed by 5% sequence divergence. Three restriction sites were identified which separated eastern and western haplotypes. No intrastrain polymorphism was detected in 150 weevils from Nebraska. Collections from Lincoln in eastern Nebraska and Scottsbluff in western Nebraska were fixed for the eastern and western haplotypes, respectively. Eastern and western haplotypes were found together in the same fields in a broad overlap region in central Nebraska
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Development of inverse modeling techniques for geothermal applications
We have developed inverse modeling capabilities for the non-isothermal, multiphase, multicomponent numerical simulator TOUGH2 to facilitate automatic history matching and parameter estimation based on data obtained during testing and exploitation of geothermal fields. The TOUGH2 code allows one to estimate TOUGH2 input parameters based on any type of observation for which a corresponding simulation output can be calculated. In addition, a detailed residual and error analysis is performed, and the uncertainty of model predictions can be evaluated. One of the advantages of inverse modeling is that it overcomes the time and labor intensive tedium of trial- and error model calibration. Furthermore, the estimated parameters refer directly to the numerical model used for the subsequent predictions and optimization studies. This paper describes the methodology of inverse modeling and demonstrates an application of the method to data from a synthetic geothermal reservoir. We also illustrate its use for the optimization of fluid reinjection into a partly depleted reservoir
An adaptive algorithm for n-body field expansions
An expansion of a density field or particle distribution in basis functions
which solve the Poisson equation both provides an easily parallelized n-body
force algorithm and simplifies perturbation theories. The expansion converges
quickly and provides the highest computational advantage if the lowest-order
potential-density pair in the basis looks like the unperturbed galaxy or
stellar system. Unfortunately, there are only a handful of such basis in the
literature which limits this advantage. This paper presents an algorithm for
deriving these bases to match a wide variety of galaxy models. The method is
based on efficient numerical solution of the Sturm-Liouville equation and can
be used for any geometry with a separable Laplacian. Two cases are described in
detail. First for the spherical case, the lowest order basis function pair may
be chosen to be exactly that of the underlying model. The profile may be cuspy
or have a core and truncated or of infinite extent. Secondly, the method yields
a three-dimensional cylindrical basis appropriate for studying galaxian disks.
In this case, the vertical and radial bases are coupled; the lowest order
radial part of the basis function can be chosen to match the underlying profile
only in the disk plane. Practically, this basis is still a very good match to
the overall disk profile and converges in a small number of terms.Comment: 16 pages, 5 figures, submitted to A
Advanced Vadose Zone Simulations Using TOUGH
The vadose zone can be characterized as a complex subsurface system in which intricate physical and biogeochemical processes occur in response to a variety of natural forcings and human activities. This makes it difficult to describe, understand, and predict the behavior of this specific subsurface system. The TOUGH nonisothermal multiphase flow simulators are well-suited to perform advanced vadose zone studies. The conceptual models underlying the TOUGH simulators are capable of representing features specific to the vadose zone, and of addressing a variety of coupled phenomena. Moreover, the simulators are integrated into software tools that enable advanced data analysis, optimization, and system-level modeling. We discuss fundamental and computational challenges in simulating vadose zone processes, review recent advances in modeling such systems, and demonstrate some capabilities of the TOUGH suite of codes using illustrative examples
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Physical barriers formed from gelling liquids: 1. numerical design of laboratory and field experiments
The emplacement of liquids under controlled viscosity conditions is investigated by means of numerical simulations. Design calculations are performed for a laboratory experiment on a decimeter scale, and a field experiment on a meter scale. The purpose of the laboratory experiment is to study the behavior of multiple gout plumes when injected in a porous medium. The calculations for the field trial aim at designing a grout injection test from a vertical well in order to create a grout plume of a significant extent in the subsurface
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Application of inverse modeling to geothermal reservoir simulation
The authors have developed inverse modeling capabilities for the non-isothermal, multiphase, multicomponent numerical simulator TOUGH2 to facilitate automatic history matching and parameter estimation based on data obtained during testing and exploitation of geothermal fields.The ITOUGH2 code allows one to estimate TOUGH2 input parameters based on any type of observation for which a corresponding simulation output can be calculated. Furthermore, a detailed residual and error analysis is performed, and the uncertainty of model predictions can be evaluated. Automatic history matching using ITOUGH2 is robust and efficient so that model parameters affecting geothermal field performance can reliably be estimated based on a variety of field measurements such as pressures, temperatures, flow rates, and enthalpies. The paper describes the methodology of inverse modeling and provides a detailed discussion of sample problems to demonstrate the application of the method to data from geothermal reservoirs
T2Well/ECO2N Version 1.0: Multiphase and Non-Isothermal Model for Coupled Wellbore-Reservoir Flow of Carbon Dioxide and Variable Salinity Water
At its most basic level, the injection of CO{sub 2} into geologic CO{sub 2} storage sites involves a system comprising the wellbore and the target reservoir. The wellbore is the only conduit available to emplace CO{sub 2} into reservoirs for long-term storage. At the same time, wellbores in general have been identified as the most likely conduit for CO{sub 2} and brine leakage from geologic carbon sequestration (GCS) sites, especially those in sedimentary basins with historical hydrocarbon production. We have developed a coupled wellbore and reservoir model for simulating the dynamics of CO{sub 2} injection and leakage through wellbores. The model describes the following processes: (1) upward or downward wellbore flow of CO{sub 2} and variable salinity water with transition from supercritical to gaseous CO{sub 2} including Joule-Thomson cooling, (2) exsolution of CO{sub 2} from the aqueous phase as pressure drops, and (3) cross flow into or interaction with layers of surrounding rock (reservoirs). We use the Drift-Flux Model and related conservation equations for describing transient two-phase non-isothermal wellbore flow of CO{sub 2}-water mixtures under different flow regimes and interacting with surrounding rock. The mass and thermal energy balance equations are solved numerically by a finite difference scheme with wellbore heat transmission to the surrounding rock handled either semi-analytically or numerically. The momentum balance equation for the flow in the wellbore is solved numerically with a semi-explicit scheme. This manual provides instructions for compilation and use of the new model, and presents some example problems to demonstrate its use
Wellbore flow model for carbon dioxide and brine
Wellbores have been identified as the most likely conduit for CO{sub 2} and brine leakage from geologic carbon sequestration (GCS) sites, especially those in sedimentary basins with historical hydrocarbon production. In order to quantify the impacts of leakage of CO{sub 2} and brine through wellbores, we have developed a wellbore simulator capable of describing non-isothermal open well flow dynamics of CO{sub 2}-brine mixtures. The mass and thermal energy balance equations are solved numerically by a finite difference scheme with wellbore heat transmission handled semianalytically. This new wellbore simulator can take as input the pressure, saturation, and composition conditions from reservoir simulators and calculate CO{sub 2} and brine fluxes needed to assess impacts to vulnerable resources. This new capability is being incorporated into the Certification Framework (CF) developed for risk assessment of GCS sites
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