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Modeling And Simulation Of Mineral Processing Systems  by R.P. King.

An approach was developed to aid in the integration of many of the biomedical findings of space flight, using systems analysis. The mathematical tools used in accomplishing this task include an automated data base, a biostatistical and data analysis system, and a wide variety of mathematical simulation models of physiological systems. A keystone of this effort was the evaluation of physiological hypotheses using the simulation models and the prediction of the consequences of these hypotheses on many physiological quantities, some of which were not amenable to direct measurement. This approach led to improvements in the model, refinements of the hypotheses, a tentative integrated hypothesis for adaptation to weightlessness, and specific recommendations for new flight experiments.

An approach was developed to aid in the integration of many of the biomedical findings of space flight, using systems analysis. The mathematical tools used in accomplishing this task include an automated data base, a biostatistical and data analysis system, and a wide variety of mathematical simulation models of physiological systems. A keystone of this effort was the evaluation of physiological hypotheses using the simulation models and the prediction of the consequences of these hypotheses on many physiological quantities, some of which were not amenable to direct measurement. This approach led to improvements in the model, refinements of the hypotheses, a tentative integrated hypothesis for adaptation to weightlessness, and specific recommendations for new flight experiments.

Models and simulations (M&S) are critical resources in the exploration of space. They support program management, systems engineering, integration, analysis, test, and operations and provide critical information and data supporting key analyses and decisions (technical, cost and schedule). Consequently, there is a clear need to establish a solid understanding of M&S strengths and weaknesses, and the bounds within which they can credibly support decision-making. Their usage requires the implementation of a rigorous approach to verification, validation and accreditation (W&A) and establishment of formal process and practices associated with their application. To ensure decision-making is suitably supported by information (data, models, test beds) from activities (studies, exercises) from M&S applications that are understood and characterized, ESMD is establishing formal, tailored W&A processes and practices. In addition, to ensure the successful application of M&S within ESMD, a formal process for the certification of analysts that use M&S is being implemented. This presentation will highlight NASA's Exploration Systems Mission Directorate (ESMD) management approach for M&S W&A to ensure decision-makers receive timely information on the model's fidelity, credibility, and quality.

This document contains the proceedings of the Training Workshop on Multiscale Modeling, Simulation and Visualization and Their Potential for Future Aerospace Systems held at NASA Langley Research Center, Hampton, Virginia, March 5 - 6, 2002. The workshop was jointly sponsored by Old Dominion University's Center for Advanced Engineering Environments and NASA. Workshop attendees were from NASA, other government agencies, industry, and universities. The objectives of the workshop were to give overviews of the diverse activities in hierarchical approach to material modeling from continuum to atomistics; applications of multiscale modeling to advanced and improved material synthesis; defects, dislocations, and material deformation; fracture and friction; thin-film growth; characterization at nano and micro scales; and, verification and validation of numerical simulations, and to identify their potential for future aerospace systems.

This document contains the proceedings of the Training Workshop on Multiscale Modeling, Simulation and Visualization and Their Potential for Future Aerospace Systems held at NASA Langley Research Center, Hampton, Virginia, March 5 - 6, 2002. The workshop was jointly sponsored by Old Dominion University's Center for Advanced Engineering Environments and NASA. Workshop attendees were from NASA, other government agencies, industry, and universities. The objectives of the workshop were to give overviews of the diverse activities in hierarchical approach to material modeling from continuum to atomistics; applications of multiscale modeling to advanced and improved material synthesis; defects, dislocations, and material deformation; fracture and friction; thin-film growth; characterization at nano and micro scales; and, verification and validation of numerical simulations, and to identify their potential for future aerospace systems.

A probabilistic structure on sequential dynamical systems is introduced here, the new model will be called Probabilistic Sequential Network, PSN. The morphisms of Probabilistic Sequential Networks are defined using two algebraic conditions. It is proved here that two homomorphic Probabilistic Sequential Networks have the same equilibrium or steady state probabilities if the morphism is either an epimorphism or a monomorphism. Additionally, the proof of the set of PSN with its morphisms form the category PSN, having the category of sequential dynamical systems SDS, as a full subcategory is given. Several examples of morphisms, subsystems and simulations are given.

A probabilistic structure on sequential dynamical systems is introduced here, the new model will be called Probabilistic Sequential Network, PSN. The morphisms of Probabilistic Sequential Networks are defined using two algebraic conditions. It is proved here that two homomorphic Probabilistic Sequential Networks have the same equilibrium or steady state probabilities if the morphism is either an epimorphism or a monomorphism. Additionally, the proof of the set of PSN with its morphisms form the category PSN, having the category of sequential dynamical systems SDS, as a full subcategory is given. Several examples of morphisms, subsystems and simulations are given.

A probabilistic structure on sequential dynamical systems is introduced here, the new model will be called Probabilistic Sequential Network, PSN. The morphisms of Probabilistic Sequential Networks are defined using two algebraic conditions. It is proved here that two homomorphic Probabilistic Sequential Networks have the same equilibrium or steady state probabilities if the morphism is either an epimorphism or a monomorphism. Additionally, the proof of the set of PSN with its morphisms form the category PSN, having the category of sequential dynamical systems SDS, as a full subcategory is given. Several examples of morphisms, subsystems and simulations are given.

These Proceedings consist of the papers and discussions presented at the Avionics Panel Meeting on Modeling and Simulation held in Paris, France, October 1979. Papers were divided as follows: 6-Tutorial, 8-C3 System Simulation, 5-Airborne Surveillance System Simulation, 5-Manned Flight Simulators, 4-Identification, Communication Navigation, and Countermeasure Simulation, and 11 on Avionics System Simulation.

Digital control systems for applications such as aircraft avionics and multibody systems must maintain adequate control integrity in adverse as well as nominal operating conditions. For example, control systems for advanced aircraft, and especially those with relaxed static stability, will be critical to flight and will, therefore, have very high reliability specifications which must be met regardless of operating conditions. In addition, multibody systems such as robotic manipulators performing critical functions must have control systems capable of robust performance in any operating environment in order to complete the assigned task reliably. Severe operating conditions for electronic control systems can result from electromagnetic disturbances caused by lightning, high energy radio frequency (HERF) transmitters, and nuclear electromagnetic pulses (NEMP). For this reason, techniques must be developed to evaluate the integrity of the control system in adverse operating environments. The most difficult and illusive perturbations to computer-based control systems that can be caused by an electromagnetic environment (EME) are functional error modes that involve no component damage. These error modes are collectively known as upset, can occur simultaneously in all of the channels of a redundant control system, and are software dependent. Upset studies performed to date have not addressed the assessment of fault tolerant systems and do not involve the evaluation of a control system operating in a closed-loop with the plant. A methodology for performing a real-time simulation of the closed-loop dynamics of a fault tolerant control system with a simulated plant operating in an electromagnetically harsh environment is presented. In particular, considerations for performing upset tests on the controller are discussed. Some of these considerations are the generation and coupling of analog signals representative of electromagnetic disturbances to a control system under test, analog data acquisition, and digital data acquisition from fault tolerant systems. In addition, a case study of an upset test methodology for a fault tolerant electromagnetic aircraft engine control system is presented.

Numerical simulations and analysis of ballistic impact and penetration by tungsten alloy rods into composite targets consisting of layers of aluminum nitride ceramic tile(s), polymer laminae, and aluminum backing are conducted over a range of impact velocities on the order of 1.0 to 1.2 km/s. Computational results for ballistic efficiency are compared with experimental data from the literature. Simulations and experiments both demonstrate a trend of decreasing ballistic efficiency with increasing impact velocity. Predicted absolute residual penetration depths often exceed corresponding experimental values. The closest agreement between model and experiment is obtained when polymer interfaces are not explicitly represented in the numerical calculations, suggesting that the current model representation of such interfaces may be overly compliant. The present results emphasize the importance of proper resolution of geometry and constitutive properties of thin layers and interfaces between structural constituents for accurate numerical evaluation of performance of modern composite protection systems.

This paper combines recent developments in the area of generation of dependent random variables with the advantages of the use of common and antithetic random numbers. This combination yields new efficient methods for estimating complicated stochastic quantities by simulation. Some theoretical and practical aspects of use of antithetic and common random numbers for variance reduction while using the total hazard construction are given. A proof of their optimality in estimating the expected value of the response sum or the response difference of functions of vector arguments with dependent components is presented. Some numerical examples illustrate the theory. (Author)

Frequently, the objective of computer simulation experiments of accounting and business systems is to find the best policy, procedure, or decision rule. Previous accounting or business simulation studies assumed that observations taken from each population were normally distributed with unknown means and known or equal variances. Unfortunately, only in rare cases can such assumptions be expected to hold. This paper introduces a multiple-ranking procedures, which allows for unknown and unequal variances, to analyze simulations of production planning and accounting control systems. The model under study is a hypothetical firm with profit and sales as multiple objectives. Two multiple objective planning models with uncertain demands are formulated, and two accounting variance analysis techniques are used and incorporated into the two planning models. A two-stage sampling procedure is used to determine the sample size. The simulated data are analyzed by a multiple-ranking procedure and then the best policy with respect to profit and sales is selected separately. Possible accounting and business applications are also mentioned. (Author)

An essential component of a Fully Distributed Processing System (FDPS) is the distributed and decentralized control. This component unifies the management of the resources of the FDPS and provides system transparency to the user. In a previous study, the problems of distributed and decentralized control were analyzed resulting in the specification of several control models. This study continues that work by further specifying the control models defined in the first report and comparing the performance of these models in various environments. This performance analysis is accomplished by means of simulation experiments. The results of the experiments indicate that the control message traffic generated by the distributed and decentralized control is much less than expected and probably does not present a barrier to the implementation of FDPSs. Comparison of the results of the simulation of a uniprocessor and that of an FDPS indicate that little or no loss of performance is experienced by the FDPS. An important limitation of these initial performance studies is the fact that user traffic is not included in this series of tests. (Author)

A method of simulating operation of a VLSI interconnect structure having capacitive and inductive coupling between nodes thereof. A matrix X and a matrix Y containing different combinations of passive circuit element values for the interconnect structure are obtained where the element values for each matrix include inductance L and inverse capacitance P. An adjacency matrix A associated with the interconnect structure is obtained. Numerical integration is used to solve first and second equations, each including as a factor the product of the inverse matrix X.sup.-1 and at least one other matrix, with first equation including X.sup.-1Y, X.sup.-1A, and X.sup.-1P, and the second equation including X.sup.-1A and X.sup.-1P.

Climate change, increased climate variability, extreme weather events, and increasing salinization pose a serious challenge to the sustainability of crop production in coastal Bangladesh. This study assessed yield performance of rice and non-rice crops under farmers’ current practices across five climate and three salinity scenarios in the south-western coastal zone. Representative village case studies in Khulna District were used to obtain data on current cropping practices and yields. A validated biophysical crop simulation model (APSIM) was used to simulate performance of crops within 10 cropping systems, representing both existing and potential future cropping patterns. The salinity impact on rice crops was simulated directly using an improved APSIM model, capable of simulating both soil salinity dynamics and the resulting rice crop response. The salinity impact on maize, wheat and sunflower was assessed by developing crop salinity response functions and applying these post-simulation to the crop yields simulated in the absence of salinity. The future performance of some existing crops, namely, watermelon, and pumpkin were extrapolated from data available in the literature and expert knowledge. Climate change is projected to have both positive and negative impacts on crop yields but growing salinity is projected to have substantial negative effects. Allowing for uncertainties inherent in the modelling process, the results indicate that loss of crop production would be negligible under projected 2030 conditions for climate and salinity, even with farmers’ current practices. Under 2060 conditions, the adverse impacts on wet-season rice, dry-season rice, and wheat remained negligible, while sunflower experienced notable yield decline. However, the effects of 2060 conditions on early wet season rice and dry-season maize were positive. Climate change in itself does not pose a major risk to crop production and aquaculture in south-west coastal Bangladesh over the next 15–45 years but increasingly salinity will have an unambiguously negative influence.

Bibliography: p. 277-285

Coarse-grain models provide an efficient means to simulate and investigate systems in which the desired behavior, property, or response is inherently at the mesoscale those that are both inaccessible to full atomistic representations and inapplicable to continuum theory. Granted, a developed coarse-grain model can only reflect the behavior included in their governing potentials and associated parameters, and consequently, the source of such parameters typically determines the accuracy and utility of the coarse-grain model. It is our contention that a complete theoretical foundation for any system requires synergistic multiscale transitions from atomic to mesoscale to macroscale descriptions. Hierarchical handshaking at each scale is crucial to predict structure property relationships, to provide fundamental mechanistic understanding, and to enable predictive modeling and material optimization to guide synthetic design efforts. Indeed, a finer-trains-coarser approach is not limited to bridge atomistic to mesoscopic scales (which is the focus of the current discussion), but can also refer to hierarchical parameterization transcending any scale, such as mesoscopic to continuum levels. Such a multiscale modeling paradigm establishes a fundamental link between atomistic behavior and the coarse-grain representation, providing a consistent theoretical approach to develop coarse-grain models for systems of various scales, constituent materials, and intended applications.

Coarse-grain models provide an efficient means to simulate and investigate systems in which the desired behavior, property, or response is inherently at the mesoscale those that are both inaccessible to full atomistic representations and inapplicable to continuum theory. Granted, a developed coarse-grain model can only reflect the behavior included in their governing potentials and associated parameters, and consequently, the source of such parameters typically determines the accuracy and utility of the coarse-grain model. It is our contention that a complete theoretical foundation for any system requires synergistic multiscale transitions from atomic to mesoscale to macroscale descriptions. Hierarchical handshaking at each scale is crucial to predict structure property relationships, to provide fundamental mechanistic understanding, and to enable predictive modeling and material optimization to guide synthetic design efforts. Indeed, a finer-trains-coarser approach is not limited to bridge atomistic to mesoscopic scales (which is the focus of the current discussion), but can also refer to hierarchical parameterization transcending any scale, such as mesoscopic to continuum levels. Such a multiscale modeling paradigm establishes a fundamental link between atomistic behavior and the coarse-grain representation, providing a consistent theoretical approach to develop coarse-grain models for systems of various scales, constituent materials, and intended applications.

AMTESS is the Army's attempt to develop an operational model and framework for acquiring modularized, generic simulation systems for maintenance training. More broadly, the AMTESS program is designed to lead toward a proven, systematized, institutionalized approach to task analysis, training requirements analysis, and fidelity analysis in support of training device acquisition. It is also designed to produce a model hardware configuration which includes a common two-dimensional display subsystem and a unique three dimensional hardware subsystem. Two prototype versions of the hardware model which vary along a number of significant dimensions (e.g., passive vs interactive use of video) Maryland. In this paper, the AMTESS prototypes will be described, along with plans and procedures for their evaluations.

Capstone is a geometry-centric platform for a unified representation of the geometry, mesh and attribution needed for engineering analyses with varying fidelity. Meshes and the attributes are both associated with a robust mathematical model of the geometry enabling any change in the geometry to be automatically propagated to the meshes and attributes needed for analyses. It provides a software platform with well abstracted and compact interfaces to create, modify and query geometry, mesh and attribution information for a model. This forms a foundation for geometry-based design environments and solvers that access geometry at runtime for scalable and accurate a-posteriori mesh adaptation.

Capstone is a geometry-centric platform for a unified representation of the geometry, mesh and attribution needed for engineering analyses with varying fidelity. Meshes and the attributes are both associated with a robust mathematical model of the geometry enabling any change in the geometry to be automatically propagated to the meshes and attributes needed for analyses. It provides a software platform with well abstracted and compact interfaces to create, modify and query geometry, mesh and attribution information for a model. This forms a foundation for geometry-based design environments and solvers that access geometry at runtime for scalable and accurate a-posteriori mesh adaptation.

Capstone is a geometry-centric platform for a unified representation of the geometry, mesh and attribution needed for engineering analyses with varying fidelity. Meshes and the attributes are both associated with a robust mathematical model of the geometry enabling any change in the geometry to be automatically propagated to the meshes and attributes needed for analyses. It provides a software platform with well abstracted and compact interfaces to create, modify and query geometry, mesh and attribution information for a model. This forms a foundation for geometry-based design environments and solvers that access geometry at runtime for scalable and accurate a-posteriori mesh adaptation.

Capstone is a geometry-centric platform for a unified representation of the geometry, mesh and attribution needed for engineering analyses with varying fidelity. Meshes and the attributes are both associated with a robust mathematical model of the geometry enabling any change in the geometry to be automatically propagated to the meshes and attributes needed for analyses. It provides a software platform with well abstracted and compact interfaces to create, modify and query geometry, mesh and attribution information for a model. This forms a foundation for geometry-based design environments and solvers that access geometry at runtime for scalable and accurate a-posteriori mesh adaptation.

Includes bibliographical references

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ADA136182

In this paper, we present an analytical model for the diffusive molecular communication (MC) system with a reversible adsorption receiver in a fluid environment. The widely used concentration shift keying (CSK) is considered for modulation. The time-varying spatial distribution of the information molecules under the reversible adsorption and desorption reaction at the surface of a receiver is analytically characterized. Based on the spatial distribution, we derive the net number of newly-adsorbed information molecules expected in any time duration. We further derive the number of newly-adsorbed molecules expected at the steady state to demonstrate the equilibrium concentration. Given the number of newly-adsorbed information molecules, the bit error probability of the proposed MC system is analytically approximated. Importantly, we present a simulation framework for the proposed model that accounts for the diffusion and reversible reaction. Simulation results show the accuracy of our derived expressions, and demonstrate the positive effect of the adsorption rate and the negative effect of the desorption rate on the error probability of reversible adsorption receiver with last transmit bit-1. Moreover, our analytical results simplify to the special cases of a full adsorption receiver and a partial adsorption receiver, both of which do not include desorption.

In this paper, we present an analytical model for the diffusive molecular communication (MC) system with a reversible adsorption receiver in a fluid environment. The widely used concentration shift keying (CSK) is considered for modulation. The time-varying spatial distribution of the information molecules under the reversible adsorption and desorption reaction at the surface of a receiver is analytically characterized. Based on the spatial distribution, we derive the net number of newly-adsorbed information molecules expected in any time duration. We further derive the number of newly-adsorbed molecules expected at the steady state to demonstrate the equilibrium concentration. Given the number of newly-adsorbed information molecules, the bit error probability of the proposed MC system is analytically approximated. Importantly, we present a simulation framework for the proposed model that accounts for the diffusion and reversible reaction. Simulation results show the accuracy of our derived expressions, and demonstrate the positive effect of the adsorption rate and the negative effect of the desorption rate on the error probability of reversible adsorption receiver with last transmit bit-1. Moreover, our analytical results simplify to the special cases of a full adsorption receiver and a partial adsorption receiver, both of which do not include desorption.

Modeling and simulation have proven invaluable to the design of various systems and planning of many experiments since the free-electron laser was invented in the 1970s. This thesis illustrates methods used for these tasks and for the validation and development of further theory. FEL systems and their components are described, briefly discussing how they fit into design considerations. Basic theory of FEL operation is reviewed, including the resonance condition, FEL wave and pendulum equations, and the concepts of undulator taper, extraction and beam quality. Two computer programs used for FEL simulation (FEL3D/FEL4D, developed at the Naval Postgraduate School, and Ginger, developed at Lawrence Berkeley National Laboratory) are discussed and compared, then applied to specific FEL cases. The cases studied serve to evaluate key performance characteristics of FELs. The final case study directly compares output from the two programs. In addition to this type of physics simulation, computer tools are also vital for component design. Relevant methods are illustrated using the example of an electrostatic cathode test cell and drawings made using the Los Alamos National Laboratories design tool, Poisson Superfish. After reviewing the principles involved and system constraints, a new test cell is designed for use with future NPS experiments. The effects of anodecathode spacing and anode aperture size are examined for two different anode configurations and recommendations are made for future design iterations.

The voltage stability of the system has become an important component for the steady and dependable functioning of the power system as a result of multiple blackouts around the world (particularly in Iraq). Distributed photovoltaic systems are a subset of decentralized power generating systems that generate electricity using renewable energy sources like solar cells, wind turbines, and water power plants. In order to size a solar-grid-connected home system properly and to confirm the impact of photovoltaics on the system, this article will also do a steady-state analysis. The heating and cooling loads were taken into account when evaluating the residential load profile. With the help of predicted energy use, the photovoltaic (PV) system was sized. The solar system's power output was calculated, and the key variables affecting system performance were examined. The DigSilent power factory 15.2 was used to simulate all of the investigations. This article achieves better system stability outcomes.

The voltage stability of the system has become an important component for the steady and dependable functioning of the power system as a result of multiple blackouts around the world (particularly in Iraq). Distributed photovoltaic systems are a subset of decentralized power generating systems that generate electricity using renewable energy sources like solar cells, wind turbines, and water power plants. In order to size a solar-grid-connected home system properly and to confirm the impact of photovoltaics on the system, this article will also do a steady-state analysis. The heating and cooling loads were taken into account when evaluating the residential load profile. With the help of predicted energy use, the photovoltaic (PV) system was sized. The solar system's power output was calculated, and the key variables affecting system performance were examined. The DigSilent power factory 15.2 was used to simulate all of the investigations. This article achieves better system stability outcomes.

This volume was digitized and made accessible online due to deterioration of the original print copy.

This volume was digitized and made accessible online due to deterioration of the original print copy.

The properties of polymer liquids on hard and soft substrates are investigated by molecular dynamics simulation of a coarse-grained bead-spring model and dynamic single-chain-in-mean-field (SCMF) simulations of a soft, coarse-grained polymer model. Hard, corrugated substrates are modelled by an FCC Lennard-Jones solid while polymer brushes are investigated as a prototypical example of a soft, deformable surface. From the molecular simulation we extract the coarse-grained parameters that characterise the equilibrium and flow properties of the liquid in contact with the substrate: the surface and interface tensions, and the parameters of the hydrodynamic boundary condition. The so-determined parameters enter a continuum description like the Stokes equation or the lubrication approximation.

We discuss two methods of an exact stochastic representation of the non-Markovian quantum dynamics of open systems. The first method employs a pair of stochastic product vectors in the total system's state space, while the second method uses a pair of state vectors in the open system's state space and a random operator acting on the state space of the environment. Both techniques lead to an exact solution of the von Neumann equation for the density matrix of the total system. Employing a spin star model describing a central spin coupled to bath of surrounding spins, we perform Monte Carlo simulations for both variants of the stochastic dynamics. In addition, we derive analytical expression for the expectation values of the stochastic dynamics to obtain the exact solution for the density matrix of the central spin.

A simulation toolbox has been developed for the creation of both steady-state and dynamic thermodynamic software models. This paper describes the Toolbox for the Modeling and Analysis of Thermodynamic Systems (T-MATS), which combines generic thermodynamic and controls modeling libraries with a numerical iterative solver to create a framework for the development of thermodynamic system simulations, such as gas turbine engines. The objective of this paper is to present an overview of T-MATS, the theory used in the creation of the module sets, and a possible propulsion simulation architecture. A model comparison was conducted by matching steady-state performance results from a T-MATS developed gas turbine simulation to a well-documented steady-state simulation. Transient modeling capabilities are then demonstrated when the steady-state T-MATS model is updated to run dynamically.

A simulation toolbox has been developed for the creation of both steady-state and dynamic thermodynamic software models. This paper describes the Toolbox for the Modeling and Analysis of Thermodynamic Systems (T-MATS), which combines generic thermodynamic and controls modeling libraries with a numerical iterative solver to create a framework for the development of thermodynamic system simulations, such as gas turbine engines. The objective of this paper is to present an overview of T-MATS, the theory used in the creation of the module sets, and a possible propulsion simulation architecture. A model comparison was conducted by matching steady-state performance results from a T-MATS developed gas turbine simulation to a well-documented steady-state simulation. Transient modeling capabilities are then demonstrated when the steady-state T-MATS model is updated to run dynamically.

A simulation toolbox has been developed for the creation of both steady-state and dynamic thermodynamic software models. This paper describes the Toolbox for the Modeling and Analysis of Thermodynamic Systems (T-MATS), which combines generic thermodynamic and controls modeling libraries with a numerical iterative solver to create a framework for the development of thermodynamic system simulations, such as gas turbine engines. The objective of this paper is to present an overview of T-MATS, the theory used in the creation of the module sets, and a possible propulsion simulation architecture. A model comparison was conducted by matching steady-state performance results from a T-MATS developed gas turbine simulation to a well-documented steady-state simulation. Transient modeling capabilities are then demonstrated when the steady-state T-MATS model is updated to run dynamically.

This work is devoted to modeling the motion of a dispersed phase in a gas flow in two cases: i) the dynamic characteristics of the gas flow (velocity components, stream functions and vorticity, ii) are found by numerically solving the Navier-Stokes equations with the subsequent construction of the droplet trajectory; study of the coalescence of droplets in a given model gas flow with analysis of the swarming of dispersed particles. In the first approach, the size and location of vortex and stagnant zones in a channel with a streamlined plate and with a turning flow are determined by numerically solving the equations of gas dynamics in Helmholtz variables. To study the coalescence of drops that occurs when the trajectories of two or more drops come into contact, a second approach has been developed-a computer model of inertial swarming in dispersed systems using the Delphi10 programming environment based on stochastic lattice algorithms and computable lattice enlargement. This approach is needed to pre-define the media flow rate profile. Also in this article, were analyzed the grouping and redistribution of particles for the manifestation of the "swarm of drops" effect.

This volume was digitized and made accessible online due to deterioration of the original print copy.

The analog work performed included the six-degree-of-freedom hover simulation; the longitudinal three-degree-of-freedom transition simulation; the longitudinal three-degree-of-freedom conversion simulation, the six-degree-of-freedom perturbation conventional flight simulation, and the simulation of gas generator control for wing-fan thrust. Supporting analyses included roll-yaw coupling and structural feedback in the pitch mode. Further work accomplished involved the stability augmentation system specification; the development of the bridge concept for roll and yaw louver control; support of various hardware tests; the generation of the specification for the DeFlorez point light source visual display; furnishing consolation services during the DeFlorez display installation and testing, and developing the yaw, roll and pitch direction cosine relationships.

and Accreditation (VV&A) session audience, a snapshot review of the Exploration Space Mission Directorate s (ESMD) investigation into implementation of a modeling and simulation (M&S) VV&A program. The presentation provides some legacy ESMD reference material, including information on the then-current organizational structure, and M&S (Simulation Based Acquisition (SBA)) focus contained therein, to provide a context for the proposed M&S VV&A approach. This reference material briefly highlights the SBA goals and objectives, and outlines FY05 M&S development and implementation consistent with the Subjective Assessment, Constructive Assessment, Operator-in-the-Loop Assessment, Hardware-in-the-Loop Assessment, and In Service Operations Assessment M&S construct, the NASA Exploration Information Ontology Model (NExIOM) data model, and integration with the Windchill-based Integrated Collaborative Environment (ICE). The presentation then addresses the ESMD team s initial conclusions regarding an M&S VV&A program, summarizes the general VV&A implementation approach anticipated, and outlines some of the recognized VV&A program challenges, all within a broader context of the overarching Integrated Modeling and Simulation (IM&S) environment at both the ESMD and Agency (NASA) levels. The presentation concludes with a status on the current M&S organization s progress to date relative to the recommended IM&S implementation activity. The overall presentation was focused to provide, for the Verification, Validation,

Several night nap-of-the-earth mission tasks were evaluated using a helmet-mounted display which provided a limited field-of-view image with superimposed flight control symbology. A wide range of stability and control augmentation designs was investigated. Variations in controller force-deflection characteristics and the number of axes controlled through an integrated side-stick controller were studied. In general, a small displacement controller is preferred over a stiffstick controller particularly for maneuvering flight. Higher levels of stability augmentation were required for IMC tasks to provide handling qualities comparable to those achieved for the same tasks conducted under simulated visual flight conditions.

A model for the optimization of simulation-based training systems was developed using a systematic, top-down design procedure. The model consists of five tools that address the following problems: (a) determining which tasks should be trained by part-mission devices, full-mission simulators, or actual equipment; (b) specifying instructional features needed to train a set of tasks efficiently; (c) specifying the levels of fidelity that should be provided along several fidelity dimensions in order to meet task training requirements and satisfy cost limits; (d) determining the family of training devices that can train all required tasks at minimum cost; and (e) determining the optimal allocation of training time to training devices, given constraints on device use. The tools share common data on task requirements, training device features, and costs. A prototype decision support system was developed, and a formative evaluation was conducted. The model was demonstrated on Army rotary-wing aviation tasks, and specifications for application to armor maintenance were deployed. The report describes the model using the IDEFO (Integrated Computer- Aided Manufacturing Definition) system modeling language.

The objective of this research was to expand the capabilities of large eddy simulation technology to contribute to the solution of urgent problems in propulsion systems and to contribute to the physical understanding of such flows. Work was initiated on both external and internal cooling flows in turbines. Results on the effects of rotation on heat transfer in channel flow are reported for heating and cooling rates of magnitudes large enough to cause significant variation in temperature dependent fluid properties. The effect of rotation was to reduce the turbulent transport near the leading wall and increase it near the trailing wall. The effect was larger for the heating flows than for the cooling flow. The ratio of Nusselt numbers on the two walls ranged between two and five, whereas the friction coefficients at the trailing wall were about twice as large as those at the leading wall. The magnitudes of streamwise and spanwise velocity fluctuations were observed to differ by about a factor of two near the two walls.

This report presents a numerical framework for analyzing the statics and dynamics of cable structures commonly encountered in oceanographic engineering practice. The numerical program, WHOI Cable, features a nonlinear solver that includes the effects of geometric and material nonlinearities, bending stiffness for seamless modeling of slack cables, and a model for the interaction of cable segments with the seafloor. The program solves both surface and subsurface single-point mooring problems, systems with both ends anchored on the bottom, and towing and drifter problems. Forcing includes waves, current, ship speed, and pay-out of cable. The programs that make-up WHOI Cable run under Unix, DOS, and Windows. There is a familiar Windows style interface available for Windows 95 and Windows NT platforms. In the report, the mathematical and numerical framework for WHOI Cable is described, followed by detailed instructions for formulating problem input files and running the codes. Examples are included in an appendix to highlight the range of problems that WHOI Cable can solve.

Briefing Charts.

The U.S. Department of Defense builds many weapons systems as Systems of Systems (SoSs). Operational testing is used to test capabilities in these SoSs, but testing all configurations of the SoSs may not be possible due to cost and the environment. Modeling and simulation (M&S) is an alternative to operationally testing all functionality and interfaces in these SoSs. An inherent deficiency of existing M&S approaches, however, lies in the emergent behavior that occurs as a result of interactions among the component systems. Applying M&S to individual components cannot detect this emergent behavior, but not detecting emergent behavior of an SoS as a whole diminishes its testing process. This dissertation develops a software architecture for an M&S framework, based on Ziegler’s theory, that makes the identification and quantification of emergent behavior possible in an SoS M&S by providing a collector of SoS metrics. This software architecture has a great advantage over the current approaches because it supports swappable and configurable components to make simulation possible over different models and parameters without costly reprogramming. This dissertation also develops an improved process for the analyst to identify and quantify emergent behavior in an SoS M&S.