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Oil and Gas Supply Modeling

Description: Abstract: The symposium on Oil and Gas Supply Modeling, held at the Department of Commerce, Washington, DC (June 18-20, 1980), was funded by the Energy Information Administration of the Department of Energy and co-sponsored by the National Bureau of Standards' Operations Research Division. The symposium was organized to be a forum in which the theoretical and applied state-of-the-art of oil and gas supply models could be presented and discussed. Speakers addressed the following areas: the realities of oil and gas supply, prediction of oil and gas production, problems in oil and gas modeling, resource appraisal procedures, forecasting field size and production, investment and production strategies, estimating cost and production schedules for undiscovered fields production regulations, resource data, sensitivity analysis of forecasts, econometric analysis of resource depletion, oil and gas finding rates, and various models of oil and gas supply. This volume documents the proceedings (papers and discussion) of the symposium.
Date: May 1982
Creator: Gass, Saul I.
Partner: UNT Libraries Government Documents Department

Excitation of a TEM Cell by a Vertical Electric Hertzian Dipole

Description: From abstract: The excitation of a transverse electromagnetic (TEM) cell by a vertical electric Hertzian dipole is analyzed where the gap between the septum and side wall is assumed to be small. Approximate expressions for the field distribution and characteristic impedance are derived. These expressions are numerically evaluated for some typical geometries, and good agreement with previously published results is shown. The formation also allows a vertical offset for the septum position, thus offering more flexibility of increasing the size of the test area to accommodate larger pieces of test equipment.
Date: March 1981
Creator: Wilson, Perry F.; Chang, David C. & Ma, Mark T.
Partner: UNT Libraries Government Documents Department

Input Impedance of a Probe Antenna Exciting a TEM Cell

Description: Abstract: The input impedance of a probe antenna exciting a transverse electromagnetic (TEM) transmission line cell is formulated by a variational approach. The formulation also utilizes the results from a previous work on the field distribution inside a TEM cell excited by a vertical electrical Hertzian dipole. The final result of imoedance is shown to consist of two distinct terms, which are respectively contributed by the ordinary rectangular waveguide and the gap perturbation. Numerical results for both the real and imaginary parts of the impedance are given. The resistive part is found to be proportional to the square of the probe length, and the reactive part largely capacitive.
Date: April 1982
Creator: Wilson, Perry F.; Chang, David C. & Ma, Mark T.
Partner: UNT Libraries Government Documents Department

Binary Solution Model for Computation of Equilibrium Compositions

Description: A NASA computer program (CEC) for calculation of complex equilibrium compositions has been modified to take into account the formation of an ideal binary solution from pure condensed species. The thermodynamics of the modification are discussed. Applications are presented.
Date: June 1978
Creator: Hsu, Chen C.; Land, Robert H. & Blander, Milton
Partner: UNT Libraries Government Documents Department

Dynamics of Wheeled Vehicles, Report 1: A Mathematical Model for the Traversal of Rigid Obstacles by a Pneumatic Tire, Appendix B: Digital Implementation of Segmented Tire Model

Description: Summary: "This appendix presents the procedures for digital implementation of the segmented tire model, developed in the basic report for an analog computer. Two procedures are required: (a) determination of the segment spring coefficient from measured load-deflection test results, and (b) computation of the resultant force vector transmitted to the axle. Digital programs for both procedures were written in Fortran IV for a GE-420 system, and are included" (p. xi).
Date: August 1969
Creator: Murphy, N. R., Jr.
Partner: UNT Libraries Government Documents Department

Digital-Transport Model Study of the Potential Effects of Coal-Resource Development on the Ground-Water System in the Yampa River Basin, Moffat and Routt Counties, Colorado

Description: From abstract: Large increases in coal mining currently (1979) taking place in the Yampa River basin are expected to continue during the 1980's and may adversely impact both the ground-water and surface-water quality in the basin. One potential source of adverse impact is the dissolution of soluble minerals contained in the overburden material disturbed during the mining. This potential impact was investigated using digital ground-water transport-modeling techniques.
Date: 1982
Creator: Warner, James W. & Dale, Robert H.
Partner: UNT Libraries Government Documents Department

Numerical Modeling Analysis of Stress Transfer Modification Concepts for Deep Longwall Mines

Description: Abstract: This U. S. Bureau of Mines (USBM) report evaluates three stress-transfermodification concepts for their potential in reducing longwall gate road stresses and closures. In each of the three concepts - packwalling, gob infilling, and entry filling - support structures are constructed on the headgate side of the panel parallel with or inby the face line. When the headgate becomes the tailgate of the adjacent panel, these structures are in place to accept stresses transferred from the mined-out panel. Using the USBM nonlinear boundary-element program MULSIM/NL, baseline models of typical longwall stress transfer behavior were developed for both intermediate depth and deep mining conditions. These models were verified by comparing model results with field measurements and observations. The stresstransfer-modification concepts were then incorporated into the deep baseline model to quantify the effects of each concept on tailgate closure. Modeling results indicated that entry filling is the most effective concept in reducing tailgate escapeway closure. Using only 18 m3 of a weak fill per meter of face advance (7.3 yd3 per ft of face advance), tailgate escapeway closure was reduced by 33%. By improving the quality of the fill, similar results were achieved using 50% less volume.
Date: 1995
Creator: Vandergrift, Thomas L. & Jude, Charles V.
Partner: UNT Libraries Government Documents Department

Climate Change Modeling and Downscaling

Description: The National Climate Assessment (NCA) Report Series summarizes regional, sectoral, and process-related workshops and discussions being held as part of the third National Climate Assessment process. This workshop focused on questions, issues, and methodological perspectives regarding the use of mathematical models for the NCA, as well as the complexities that arise when applying data and models to multiple spatial and temporal scales.
Date: 2010-12-08/2010-12-10
Creator: U.S. Global Change Research Program
Partner: UNT Libraries Government Documents Department

Digital Models of a Glacial Outwash Aquifer in the Pearl-Sallie Lakes Area, West-Central Minnesota

Description: From purpose and scope: The purpose of this investigation is to 1) study the hydrologic system in a glaciated terrain typified by numerous lakes, with particular focus on the effects of lake-ground-water interchange, 2) simulate the natural system by using two digital modeling methods--areal (map view) and vertical section, and 3) evaluate the utility of the models and determine the kinds and amount of basic data needed to obtain reasonable simulations.
Date: November 1975
Creator: Larson, Steven P.; McBride, Mark S. & Wolf, Ronald J.
Partner: UNT Libraries Government Documents Department

Constitutive models in LAME.

Description: The Library of Advanced Materials for Engineering (LAME) provides a common repository for constitutive models that can be used in computational solid mechanics codes. A number of models including both hypoelastic (rate) and hyperelastic (total strain) constitutive forms have been implemented in LAME. The structure and testing of LAME is described in Scherzinger and Hammerand ([3] and [4]). The purpose of the present report is to describe the material models which have already been implemented into LAME. The descriptions are designed to give useful information to both analysts and code developers. Thus far, 33 non-ITAR/non-CRADA protected material models have been incorporated. These include everything from the simple isotropic linear elastic models to a number of elastic-plastic models for metals to models for honeycomb, foams, potting epoxies and rubber. A complete description of each model is outside the scope of the current report. Rather, the aim here is to delineate the properties, state variables, functions, and methods for each model. However, a brief description of some of the constitutive details is provided for a number of the material models. Where appropriate, the SAND reports available for each model have been cited. Many models have state variable aliases for some or all of their state variables. These alias names can be used for outputting desired quantities. The state variable aliases available for results output have been listed in this report. However, not all models use these aliases. For those models, no state variable names are listed. Nevertheless, the number of state variables employed by each model is always given. Currently, there are four possible functions for a material model. This report lists which of these four methods are employed in each material model. As far as analysts are concerned, this information is included only for the awareness purposes. The analyst can take ...
Date: September 1, 2007
Creator: Hammerand, Daniel Carl & Scherzinger, William Mark
Partner: UNT Libraries Government Documents Department

The power of sensitivity analysis and thoughts on models with large numbers of parameters

Description: The regulatory systems that allow cells to adapt to their environments are exceedingly complex, and although we know a great deal about the intricate mechanistic details of many of these systems, our ability to make accurate predictions about their system-level behaviors is severely limited. We would like to make such predictions for a number of reasons. How can we reverse dysfunctional molecular changes of these systems that cause disease? More generally, how can we harness and direct cellular activities for beneficial purposes? Our ability to make accurate predictions about a system is also a measure ofour fundamental understanding of that system. As evidenced by our mastery of technological systems, a useful understanding ofa complex system can often be obtained through the development and analysis ofa mathematical model, but predictive modeling of cellular regulatory systems, which necessarily relies on quantitative experimentation, is still in its infancy. There is much that we need to learn before modeling for practical applications becomes routine. In particular, we need to address a number of issues surrounding the large number of parameters that are typically found in a model for a cellular regulatory system.
Date: January 1, 2008
Creator: Havlacek, William
Partner: UNT Libraries Government Documents Department

Testing of constitutive models in LAME.

Description: Constitutive models for computational solid mechanics codes are in LAME--the Library of Advanced Materials for Engineering. These models describe complex material behavior and are used in our finite deformation solid mechanics codes. To ensure the correct implementation of these models, regression tests have been created for constitutive models in LAME. A selection of these tests is documented here. Constitutive models are an important part of any solid mechanics code. If an analysis code is meant to provide accurate results, the constitutive models that describe the material behavior need to be implemented correctly. Ensuring the correct implementation of constitutive models is the goal of a testing procedure that is used with the Library of Advanced Materials for Engineering (LAME) (see [1] and [2]). A test suite for constitutive models can serve three purposes. First, the test problems provide the constitutive model developer a means to test the model implementation. This is an activity that is always done by any responsible constitutive model developer. Retaining the test problem in a repository where the problem can be run periodically is an excellent means of ensuring that the model continues to behave correctly. A second purpose of a test suite for constitutive models is that it gives application code developers confidence that the constitutive models work correctly. This is extremely important since any analyst that uses an application code for an engineering analysis will associate a constitutive model in LAME with the application code, not LAME. Therefore, ensuring the correct implementation of constitutive models is essential for application code teams. A third purpose of a constitutive model test suite is that it provides analysts with example problems that they can look at to understand the behavior of a specific model. Since the choice of a constitutive model, and the properties that are used in ...
Date: September 1, 2007
Creator: Hammerand, Daniel Carl & Scherzinger, William Mark
Partner: UNT Libraries Government Documents Department

Burner Stabilized Flames in Fluids

Description: In this report it is shown that a burner placed in a combustible fluid can have a stabilizing effect on a plane flame. A mathematical model is derived in which the flame is modeled as a surface of discontinuity in the flow field. Jump conditions for the fluid variables, as well as an expression for the flame speed, are obtained from an asymptotic analysis of the detailed structure of the flame. The model is applied to investigate the linear stability of a plane flame. Stable behavior is shown to exist for certain regimes of the parameters: Lewis number, burner strength, heat release and inflow velocity.
Date: July 1984
Creator: Kaper, H. G.; Leaf, Gary K.; Matalon, Moshe & Matkowsky, Bernard J.
Partner: UNT Libraries Government Documents Department

Reference Flat Pulse Generator

Description: Introduction: A reference step-like pulse generator is described which has been developed at NBS. This generator can be used for accurately characterizing the step response of various kinds of trap ient recording equipment (oscilloscopes, waveform recorders, transient digitizers, etc.). Basic design principles are given as well as complete circuit diagrams and descriptions. An analysis of the output stage of the generator is presented together with the circuit models for developing a time-domain computer simulation program using extended- SCEPTRE. Preliminary specifications indicate that the NBS Reference Flat Pulse Generator provides a negative-going reference transition duration (90 to 10 percent) of 600 ps, *20 percent with baseline perturbations of less than *2 percent for less than 5 ns.
Date: October 1983
Creator: Andrews, J. R.; Bell, B. A. & Baldwin, E. E.
Partner: UNT Libraries Government Documents Department