This thesis describes Monte-Carlo computer simulations of binary alloys, with comparisons between small angle neutron scattering (SANS) data, and numerically integrated solutions to the Cahn-Hilliard-Cook (CHC) equation. Elementary theories for droplet growth are also compared with computer simulated data. Monte-Carlo dynamical algorithms are investigated in detail, with special regard for universal dynamical times. The computer simulated systems are Fourier transformed to yield partial structure functions which are compared with SANS data for the binary Iron-Chromium system. A relation between real time and simulation time is found. Cluster statistics are measured in the simulated systems, and compared to droplet formation in the Copper-Cobalt system. Some scattering data for the complex steel PE16 is also discussed. The characterisation of domain size and its growth with time are investigated, and scaling laws fitted to real and simulated data. The simple scaling law of Lifshitz and Slyozov is found to be inadequate, and corrections such as those suggested by Huse, are necessary. Scaling behaviour is studied for the low-concentration nucleation regime and the high-concentration spinodal-decomposition regime. The need for multi-scaling is also considered. The effect of noise and fluctuations in the simulations is considered in the MonteCarlo model, a cellular-automaton (CA) model and in the Cahn-Billiard-Cook equation. The Cook noise term in the CHC equation is found to be important for correct growth scaling properties.

Thesis. 1975. Ph.D.--Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science. / Vita. / Bibliography: leaves 121-125. / Ph.D.

[by] Bernard Gold and Lawrence R. Rabiner. / Bibliography: p. 36. / Contract DA 28-043-AMC-02536(E). Project no. 200-14501-B31F.

One of the commonly used simulation approaches is process orientation. This is based on the use of nodes (or blocks) that perform functions in series. In spite of the compactness and ease of learning that characterize process-based simulation, many languages are somewhat complex, primarily the result of the large number of nodes that users have to deal with and the considerable gulf between a user's abstract notion of the model and the details required to implement it. This paper describes a process-based simulation system that integrates object-oriented programming, visual interactive simulation and graphical model specification. Object-oriented programming techniques and simulation seem to be a natural match. The process classes are represented as network blocks or network nodes, and the process as a network diagram or directed graph. Arcs connect the nodes and specify the next step in the process. Each block type has its own icon. Developing an application model requires selecting a set of nodes, connecting them, and specifying the parameters (such as activity durations and random number streams) of the nodes through dialog boxes or inspection panels. Nodes have been designed to accomplish the major requirements in simulation modeling, including creation and termination of entities, attribute assignment, branching, queues and resources, activity specification and statistics collection and display. Additional system features include: statistics manipulation for steady state results, execution trace utilities, and limited animation capabilities. The system has been implemented for the NeXT programming environment using Objective-C. The NeXT includes an extensive object-oriented user interface library, relatively powerful hardware, and a modern multi-tasking and virtual memory operating system. Objective-C allows object-oriented concepts such as inheritance and subclassing while adding only a few constructs to that of the C language. The system modeling environment developed in this research enhances the applicability and usability of high level modeling tools. The program also provides a platform for further work on the distribution of the modeling process over several cooperating, communicating applications. / Graduation date: 1992

The intent of this thesis is to show the usefulness simulating of an instruction set in software and to demonstrate the feasibility of doing so by providing the framework of a simulation program.The design of new computer architectures and computer based control systems is a trial and error process. Normal design practice is to design and build a prototype of the new system and then evaluate the performance of the prototype. Designing complex systems in this manner is very time consuming and expensive; using a software program to simulate the operation of the new system can help solve certain design problems and shorten the development time and effort.The instruction set simulator executes a subset of the 8086 instruction set and contains routines that are useful in debugging the target software.The feasibility of implementing an instruction set simulator to solve certain design problems has been demonstrated by implementing the most commonly used op codes from the 8086 instruction set.Ball State UniversityMuncie, IN 47306

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 154-176). Available also in a digital version from Dissertation Abstracts.

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