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Molecular dynamics at constant temperature and pressureDecker, Mike W. 02 November 1995 (has links)
Molecular dynamics is a technique in which the
trajectories of a group of particles are calculated as a
function of time by integrating the equations of motion. In
this thesis we study the use of molecular dynamics for atoms
in a crystal.
A model is introduced which describes interactions of a
physical system with an external heat reservoir in molecular
dynamics simulations. This is accomplished by the addition
of a "virtual variable" to the Hamiltonian which is used to
scale time. Aspects of this model are discussed and
examples are presented for a simple system.
Similarly, a constant pressure model is introduced in
which additional virtual volume variables are added to the
Hamiltonian. The volume and shape of the molecular dynamics
cell are now free to vary. Simple examples are discussed.
Aspects of the computer programs and the algorithms are
explained. Particular attention is focused on the methods
used to integrate the equations of motion and to calculate
the coulomb interactions.
Examples of simulations using a zirconium oxide crystal
are presented. We study the effects of heat bath and
pressure bath simulations, both separately and in
combination. Various features of the behavior are
investigated with the primary focus on phase changes,
numerical errors, and parameters describing the heat and
pressure baths. / Graduation date: 1996
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Computer simulation of secondary structure of biological and synthetic macromoleculesZhang, Wei. January 2009 (has links)
Thesis (Ph.D)--Chemical Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Ludovice, Pete; Committee Member: Chen, Rachel; Committee Member: Harvey, Steve; Committee Member: Sambanis, Athanassios; Committee Member: Wartell, Roger. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Interface cohesion relations based on molecular dynamics simulationsSpearot, Douglas Edward 05 1900 (has links)
No description available.
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The development and application of a kinematic stormwater management modelColeman, Trevor John January 1990 (has links)
A project report submitted to the Faculty of Engineering, University
of the Witwatersrand, Johannesburg in partial fulfillment of the
requirements for the degree of Master of Science in Engineering. / Urban stormwater drainage designers and planners are having to deal
with the dramatic effect that urbanization has on the hydrological
regime.
To cope economically with the increases in runoff volumes and
peaks due to urbanization, more sophisticated approaches are required
for the design and planning of stormwater drainage systems. [Abbreviated abstract. Open document to view full version] / AC2017
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Initial spatial motion of a rigid body on removal of one constraintBatra, Ajoy 19 October 1993 (has links)
This thesis presents a discussion of motion of a six-legged walking
machine following removal of one leg constraint. To take a step, one leg
must be lifted and placed at some other position. As soon as the constraint
provided by the leg is removed, however the machine begins to fall. This
falling motion can be represented as screw motion of the body center of
mass and of body-leg attachments.
First a study of body workspace of the machine was done with all six
feet on the ground. Body workspace is the intersection of kinematic and
force workspaces. Kinematic workspace is the volume in space where the
center of mass can be placed such that all joint angles of legs are within
specified limits; and force workspace is the volume in space where the force
in all legs is compressive. The affect of various foot positions, pitches and
heights of the center of mass were investigated to find a set of three
symmetric foot positions that might constitute acceptable intermediate
positions in a walking sequence.
Motion of the center of mass in the forward direction is limited in the
force workspace by two points at which the force on a pair of legs goes to
zero. With the center of mass at each of these two positions, the screw
parameters resulting from the release of force on one leg (front, middle and
hind individually) could be determined.
Dynamic simulation of these body and foot positions used the
commercial software SD/FAST. Code was written in C to do both static and
dynamic simulation of machine and merged with code generated by
SD/FAST. Code was also written in Auto Lisp to plot the falling motion of
machine.
Screw parameters found in this study were such that sustained
forward motion of the body could not be achieved using the falling motion
alone. Other measures such as extending one or more of the remaining five
legs would be needed for effective forward body motion. / Graduation date: 1994
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Feature tracking in two dimensional time varying datasetsThampy, Sajjit. January 2003 (has links)
Thesis (M.S.)--Mississippi State University. Department of Computational Engineering. / Title from title screen. Includes bibliographical references.
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A hierarchy based interface for integration of scientific applicationsDoddamani, Niranjana Sharma. January 2003 (has links)
Thesis (M.S.)--Mississippi State University. Department of Computational Engineering. / Title from title screen. Includes bibliographical references.
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Flexible multibody analysis of thin structures with actuated componentsChoi, Jou-Young 12 1900 (has links)
No description available.
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A computer imaging method for fluid motion studies in metal castingPoland, John H. 17 August 1993 (has links)
Significant reductions in the number of defects in parts
produced by investment casting can be obtained by improving
the flow of the molten metal during pouring. Studies have
been done at Oregon State University with simulated casting
techniques to determine optimal mold configurations.
Better mold layouts have been shown to improve this flow.
The purpose of this project was to develop a computer
imaging system that would aid in reliably evaluating these
experiments. The completed system consisted of a computer,
a frame grabber, video equipment and operating software.
Videotapes made of the fluid flow in the mold during the
pouring process were replayed into the computer and
evaluated. Custom software reduced the collected data to a
representative evaluation number.
Results show that the computer evaluations are reliable
and reproducible, but applications are limited because of
the cost, speed and power of available computer systems. / Graduation date: 1994
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The computational fluid dynamics analysis and optimisation of process vessels used in the manufacture of military propellants and high explosivesLea, Jimmy, Chemical Sciences & Engineering, Faculty of Engineering, UNSW January 2007 (has links)
This research focuses on the computational fluid dynamics modelling and simulation of the existing reactors and mixing tanks employed by the Australian Defence Industries to manufacture military propellants for gun projectiles and small rockets; high explosives for naval gun projectiles and aerial bombs. The main objective of this research is to gain a thorough understanding of these process vessels via research and to provide recommendations to improve their performance. Reactors and mixing tanks were chosen as the test unit operations because although they contribute significantly to the manufacturing process, reactors have frequently been poorly understood or in the case of mixing tanks, taken for granted. Consequently, there is a lack of comprehensive knowledge to support successful operations of these process vessels. In addition, this research also recommends using photocatalysis technology to destroy liquid wastes produced from such manufacturing activities. For each product, a full characterisation was provided that included detailed theoretical analyses that presents a unique insight into the hydrodynamics occurring in these process vessels. The credibility of theoretical predictions was demonstrated via qualitative and quantitative validation using particle image velocimetry. Results from characterisation showed that the reactors and mixing tanks employed in the manufacture of military propellants, high explosives or aerial bombs were operating at sub-optimum conditions. To tackle this shortcoming, four ideal geometrical configurations that promised optimum performance were proposed for each of the test studies. These included a designer reactor for the manufacture of military propellants and effective mixing tanks for suspending high explosive particles, blending different high explosives and for manufacturing aerial bombs. The correct implementation of these recommendations will provide an optimum operation that achieves high product throughput and concurrently reduces reject rate. Research was also conducted to formulate a set of multipurpose design guidelines for a suspension mixing tank. The design template created from the results will provide valuable information to researchers across industries in their quest to optimise any unit suspension mixing tank operated on the principle of mechanical agitation. Finally, modelling of reactive species was conducted on a laboratory-scale photoreactor, involving physical experiments to destroy toxic effluent aqueous phase.
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