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Build Time Estimations for Large Scale Modelling
Achieving speedy results in model making is very much desired if not a necessity in ahnost any
manufacturing industry. There is no doubt that rapid prototyping contributes to this process. It is
generally considered that when compared to conventional machining techniques like nlilling, the
current rapid prototyping systems appear to be much faster. This is certainly true for complex,slnall
objects. I-Iowever, this is not alwaysa,pplicable to simple, large and bulky parts.
There are a number of projects and systems concentrating on the fabrication of large models. Work
is being carried out at the University ofHong Kong, using milling. along with slicing technology.
This.report compares some ofthe rapid prototyping systems witl1milling. Milling is an established
technology and recent developments in materials and nlachines used in Inilling nlake it a good
alternative to rapid prototyping when itcomes to largesyale nl0delling.Mechanical Engineerin
The Impact of Professional Sports on Cities’ Economic Performance
The purpose of this paper is to estimate the impact of professional sports on cities’ economic performance as measured by real per capita income growth and changes in the unemployment rate. We use a panel model across 43 cities over eight years. Explanatory variables include the number of professional sports franchises in a city and the performance of those franchises. We find no statistically significant evidence suggesting that professional sports franchises impact cities’ real per capita income growth. We do, however, find that professional sports franchises have a statistically significant impact on unemployment rates
Theoretical investigations of r-f induction heated plasmas
Radio frequency induction heated plasmas with power deposition and energy remova
Experimental investigations of heavy-gas containment in r-f heated and unheated two- component vortexes
Heavy gas concentration in light gas vortices for heated and unheated vortex flow
Stigma Reduction Techniques/Campaigns for Practitioners in a Rural Community Mental Health Practice
The purpose of this project was to systematically review the literature on the negative effects of stigma on the therapy seeking clients of rural mental health centers. Also to provide information on anti-stigma campaign efforts. The goal of anti-stigma programs are to create awareness about how stigma affects people with mental illnesses, and to have participants develop a sense of what it means to walk in the shoes of a person with mental illness (Corrigan, 2004, p. 19). The research question was how do we help people from being victimized by the prejudice and discrimination that arises from stigma
Mass selected low energy ion-assisted growth of epitaxial GaN thin films: Impact of the nitrogen ion species
In this thesis, a custom quadrupole mass filter setup was established to independently investigate the impact of the most prominent ion species that are present during ion-assisted deposition. The setup was applied to the low temperature epitaxial growth of GaN thin films on 6H-SiC substrates. Atomic nitrogen ions at higher ion kinetic energies were for the first time independently identified to be the predominant cause of deteriorating crystalline qualities during growth. Precise control of the ion beam parameters yielded the capability to vary the average GaN phase content from almost purely wurtzite to the meta-stable zinc blende GaN phase. Even in case of comparably high crystalline quality, the atomic and molecular nitrogen ions were independently determined to yield distinct thin film topographies throughout the entire observed evolution of the thin film formation.:Bibliographical Description
1 Introduction
1.1 Epitaxial Thin Film Growth
1.2 Ion-Beam Assisted Deposition
1.2.1 Influence of Energetic Particles
1.2.2 Ion-atom Arrival Ratio
1.3 Gallium Nitride
2 Methods
2.1 Setup of the Deposition System
2.1.1 Knudsen Effusion Cell
2.1.2 Reflection High-Energy Electron Diffraction
2.1.3 Auger Electron Spectroscopy
2.1.4 Ion Sources
2.2 Quadrupole Mass Filter System
2.2.1 Components
2.2.2 Working Principle of a Quadrupole Mass Filter
2.2.3 Alternative Mass Filters
2.3 X-ray Diffraction and Reflectivity
2.4 Atomic Force Microscopy
2.5 Transmission Electron Microscopy
3 Results and Discussions
3.1 Characterization of the Quadrupole Mass Filter System
3.1.1 Mass Filter Performance and Resolution
3.1.2 Ion Beam Characteristics
3.1.3 Space Charge Considerations
3.1.4 Conclusions
3.2 Influence of the I/A Ratio and Ion Kinetic Energy
3.2.1 Determination of the GaN Phase Composition
3.2.2 Film Topography and Growth Mode
3.2.3 Crystal Structure and Orientation
3.2.4 Microstructure at the Interface
3.2.5 Conclusions
3.3 Impact of the Ion Species on Growth Instabilities
3.3.1 Growth Rates and Thin Film Topography
3.3.2 Crystal Structure
3.3.3 Growth Mode and RHEED pattern evolution
3.3.4 Conclusions
4 Summary and Conclusions
Bibliography
Complete Publication List of the Author
Acknowledgments
Declaration of AuthorshipIn dieser Arbeit wurde ein maßgefertigter Quadrupol-Massenfilteraufbau etabliert, um die Auswirkungen der prominentesten Ionenspezies, die während der ionengestützten Abscheidung vorhanden sind, unabhängig voneinander zu untersuchen. Der Aufbau wurde für das epitaktische Niedertemperatur-Wachstum von GaN-Dünnschichten auf 6H-SiC-Substraten angewendet. Atomare Stickstoffionen bei höheren kinetischen Ionenenergien wurden zum ersten Mal in der Abwesenheit anderer Spezies als die dominierende Ursache für die Verschlechterung der kristallinen Qualität während des Wachstums identifiziert. Eine präzise Kontrolle der Ionenstrahlparameter ergab die Fähigkeit, den durchschnittlichen GaN-Phasengehalt von der fast reinen Wurtzit- bis zur metastabilen Zinkblende-GaN-Phase zu variieren. Selbst bei vergleichbar hoher kristalliner Qualität weisen die mit atomaren und molekularen Stickstoffionen hergestellten Schichten unabhängig voneinander verschiedene Topographien auf, die sich während der gesamten beobachteten Entwicklung der Dünnschichtbildung deutlich abzeichneten.:Bibliographical Description
1 Introduction
1.1 Epitaxial Thin Film Growth
1.2 Ion-Beam Assisted Deposition
1.2.1 Influence of Energetic Particles
1.2.2 Ion-atom Arrival Ratio
1.3 Gallium Nitride
2 Methods
2.1 Setup of the Deposition System
2.1.1 Knudsen Effusion Cell
2.1.2 Reflection High-Energy Electron Diffraction
2.1.3 Auger Electron Spectroscopy
2.1.4 Ion Sources
2.2 Quadrupole Mass Filter System
2.2.1 Components
2.2.2 Working Principle of a Quadrupole Mass Filter
2.2.3 Alternative Mass Filters
2.3 X-ray Diffraction and Reflectivity
2.4 Atomic Force Microscopy
2.5 Transmission Electron Microscopy
3 Results and Discussions
3.1 Characterization of the Quadrupole Mass Filter System
3.1.1 Mass Filter Performance and Resolution
3.1.2 Ion Beam Characteristics
3.1.3 Space Charge Considerations
3.1.4 Conclusions
3.2 Influence of the I/A Ratio and Ion Kinetic Energy
3.2.1 Determination of the GaN Phase Composition
3.2.2 Film Topography and Growth Mode
3.2.3 Crystal Structure and Orientation
3.2.4 Microstructure at the Interface
3.2.5 Conclusions
3.3 Impact of the Ion Species on Growth Instabilities
3.3.1 Growth Rates and Thin Film Topography
3.3.2 Crystal Structure
3.3.3 Growth Mode and RHEED pattern evolution
3.3.4 Conclusions
4 Summary and Conclusions
Bibliography
Complete Publication List of the Author
Acknowledgments
Declaration of Authorshi
Package Conveyance Stability Project
Dematic’s new model of conveyor is called the 9570 unit and is a highspeed live roller conveyor. This new model is designed to transport packages while maintaining a high speed of at least 3 m/s. While this new unit was being tested at the Dematic Tech center, it was discovered that when small and light weight packages get diverted onto the unit, they experience turbulence which causes the packages to spin or flip over. Orientation of packages on conveyor is extremely important for scanning purposes. In order to fix this problem, the problem first had to be replicated. A piece of the 9570 unit was sent to Central Washington University (CWU) to be reconstructed and manipulated. Once the conveyor was assembled, initial testing was done to recreate the same problem. After the problem was replicated, different variables were manipulated in order to determine how they affect the turbulence of packages. These variables included, changing the diverting location onto the conveyor or changing the speed the packages are diverted onto the conveyor. The testing concluded that in order to decrease the turbulence of small packages when being diverted onto the 9570, the diverting speed needs to be adjusted so that the packages are coming into contact with the rollers at a higher speed that what the unit is running at
USDA Organic: Ecopornography or a Label Worth Searching For?
Ecopornography,” more commonly known as greenwashing, is a term that applies to any entity that disseminates disinformation in order to promote an environmentally friendly public image without actually taking significant action to protect the environment. Greenwashing is pervasive and a nearly unavoidable component of consumers’ evaluations of potential purchases. Food producers and packagers are often guilty of greenwashing their products to appeal to the environmentally conscious consumer by using such terms as “free range” or “all natural.” The United States Department of Agriculture (“USDA”) has set standards for the use of the word “organic” on food labels. These standards, while significantly more meaningful than those behind the “free range” label, are by no means the most stringent in the world. Is the USDA organic label indicative of an environmentally friendly product or is it greenwashing
Experimental investigation of the spectral emission characteristics of argon-tungsten and argon-uranium induction heated plasmas
Spectral emission characteristics of gaseous tungsten and uranium in induction heated argon plasma
Containment experiments in vortex tubes with radial outflow and large superimposed axial flows
Containment tests of vortexes with radial outflow in basic vortex tube, and in axial-flow vortex tub
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