2005 MU theses - Freely available onlinehttps://hdl.handle.net/10355/40492024-03-19T12:30:35Z2024-03-19T12:30:35ZAnalysis of heat transfer in subcooled metal powder subjected to pulsed laser heatingKonrad, Chad E.https://hdl.handle.net/10355/43002020-08-06T03:50:44Z2005-01-01T00:00:00ZAnalysis of heat transfer in subcooled metal powder subjected to pulsed laser heating
Konrad, Chad E.
The interaction of metal powder and pulsed laser heat flux is investigated on two levels, the powder bed level and the particle level. The locations of the thermal penetration depth and the liquid-solid interface are obtained using the integral approximate method. Melting and resolidification of a subcooled, two-component metal powder bed subjected to temporal Gaussian heat flux is investigated analytically. An increase in heat source intensity or powder bed porosity will result in an increase of the melt pool depth, melt pool temperature, and the overall processing time. The melt pool becomes shallower with increasing subcooling. Heat conduction in a single subcooled metal powder particle subjected to nanosecond pulsed laser heating is also investigated analytically. A change in the repetition rate of the laser or an increase in maximum heat flux will result in a larger temperature rise on the surface of the particle, as well as a higher thermalized particle temperature after the laser pulse is finished. Although a discrepancy exists where peak surface temperatures are concerned, the thermalized temperatures of different-sized spheres are all the same. The time at which the particle is fully penetrated is only affected by a change in thermal diffusivity, laser pulse width, or particle radius. The physical model and results of this investigation pave the way for further modeling of Selective Laser Sintering (SLS) processes with a pulsed laser.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.; Title from title screen of research.pdf file viewed on (July 14, 2006); Includes bibliographical references.; Thesis (M.S.) University of Missouri-Columbia 2005.; Dissertations, Academic -- University of Missouri--Columbia -- Mechanical and aerospace engineering.
2005-01-01T00:00:00ZAnalysis of lubrication groove geometryNoronha, Noel Johnhttps://hdl.handle.net/10355/43172020-08-06T04:44:26Z2006-01-01T00:00:00ZAnalysis of lubrication groove geometry
Noronha, Noel John
Lubrication is process of using lubricants in moving machine components to reduce friction and wear between them and consequently to improve their running life. In this thesis, a groove is introduced in these components and the various groove parameters that could influence better lubrication has been analyzed. The lubricating system considered in this thesis is a moving flat plate with a rectangular groove in it while its external housing is stationary. Equations that govern the flow rate, force and torque for this groove have been derived and analyzed. Sensitivity analysis of flow, force and torque has been done taking into consideration a short groove with deep depth and a long groove with shallow depth. Based on the results obtained it is possible to determine the importance of each groove parameter in effective lubrication and to eliminate those that do not have any influence.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.; Title from title screen of research.pdf file viewed on (May 20, 2007); Includes bibliographical references.; Vita.; Thesis (M.S.) University of Missouri-Columbia 2006.; Dissertations, Academic -- University of Missouri--Columbia -- Mechanical and aerospace engineering.
2006-01-01T00:00:00ZAnalysis of the enzymatic networkMummaneni, Avanthihttps://hdl.handle.net/10355/42852020-11-24T16:28:52Z2005-01-01T00:00:00ZAnalysis of the enzymatic network
Mummaneni, Avanthi
A biochemical network is very large, complex system with very diverse components. In order to study the behavior of networks, the first step is to study their architecture. Studying network architecture raises many basic questions about its connectivity. In order for me to answer all these questions, I was embarked on the task of building a biochemical network. The Enzyme Nomenclature Database (END) contains information on all systematically classified enzymatic reactions. The data of END represent a basic notion of a biochemical network. I did various calculations and implemented several algorithms to study the architecture of the network of these enzymatic reactions in END. Most of the reactions in the network have reactive conjuction degrees of four and five and most compounds are connected to only one reaction. The network can be connected into a single large component by compounds of low degree. There are more branced regions in the network than simple straight paths. There are many more regions densely connected internally than their immediate context.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.; Title from title screen of research.pdf file viewed on (January 22, 2007); Includes bibliographical references.; Thesis (M.S.) University of Missouri-Columbia 2005.; Dissertations, Academic -- University of Missouri--Columbia -- Computer science.
2005-01-01T00:00:00ZAn application of machine learning techniques to interactive, constraint-based searchHarbert, Christopher W.https://hdl.handle.net/10355/43242020-08-06T04:44:36Z2005-01-01T00:00:00ZAn application of machine learning techniques to interactive, constraint-based search
Harbert, Christopher W.
Search engine users frequently place additional constraints on search results that are not included in the user's original query. To respond to these additional constraints, search engine designers frequently add an "advanced search" page. On these pages, the user supplies a set of constraints for the result items. While this is certainly more useful, it relies on two assumptions: that the user knows these constraints prior to the search, and that the constraints are independent. This is not always the case. This work presents a method to use an existing search engine to create an interactive, constraint-based search: the Query Expansion and Refinement Process (QUERP). In addition, this work provides an example of the method as applied to the popular eBay auction site. The experimental results show that using QUERP to provide an interactive, constraint-based search has the potential to provide higher precision and recall than the original search engine.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.; Title from title screen of research.pdf file viewed on (December 12, 2006); Includes bibliographical references.; Thesis (M.S.) University of Missouri-Columbia 2005.; Dissertations, Academic -- University of Missouri--Columbia -- Computer science.
2005-01-01T00:00:00Z