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Articles 1 - 7 of 7

Full-Text Articles in Engineering Science and Materials

Trifluoroiodomethane As An Environmentally Friendly Gas For Water Patterning By Plasma Etching Process, Krit Aryusook Jan 1997

Trifluoroiodomethane As An Environmentally Friendly Gas For Water Patterning By Plasma Etching Process, Krit Aryusook

Theses

Trifluoroiodomethane (CF3I), a non-global warming gas, has been investigated with study as a substitute for typical CFC etchants, such as CF4 and C2F6, used in wafer pattering technology. This investigation was carried out by exposing dielectric films of silicon oxide (SiO2) and silicon nitride (Si3N4) in CF3I and C2F6/O2 (used as a reference) plasma environments. The etch rate of these films was ascertained as function of applied rf power, etchant gas flow rate, reaction chamber operating pressure, and O2 to CF3 ...


Microporous Silicon Dioxide/Vycor Membranes For Gas Separation, Justin R. Barone Jan 1997

Microporous Silicon Dioxide/Vycor Membranes For Gas Separation, Justin R. Barone

Theses

This study focused on producing membranes for molecular sieving of gases by reducing the pore size of an already existing membrane structure. To do this, SiO2 was deposited inside the pores of a Vycor tube with initial pore diameter of 4 nm. The film deposition took place by a low pressure chemical vapor deposition (LPCVD) process where diethylsilane (DES) and nitrous oxide (N2O) were used as precursor gases. A counterflow reactant geometry was used where the precursor gases were flowed on both sides of the porous membrane. This deposition geometry gave higher selectivities and better mechanical stability ...


Synthesis And Characterization Of Silicon Dioxide Thin Films By Low Pressure Chemical Vapor Deposition, Sutham Niyomwas Jan 1997

Synthesis And Characterization Of Silicon Dioxide Thin Films By Low Pressure Chemical Vapor Deposition, Sutham Niyomwas

Theses

Ditertiarybutylsilane ( DTBS ) and oxygen have been used as precursors to produce silicon dioxide films by low pressure chemical vapor deposition. These films were synthesized in the temperature range of 600°C to 800°C at constant pressure, and at different gas flow composition. The films were found to be uniform with a composition that varied with deposition temperature and gas flow ratio. The growth rate was found to follow an Arrhenius behavior with an apparent activation energy of 2.62 kcal/mol. The growth rate was seen to increase with higher distance between wafers and to vary as a function ...


Measurement And Analysis Of Lawn Mower Performance And Noise, Matthew D. Moore Jan 1997

Measurement And Analysis Of Lawn Mower Performance And Noise, Matthew D. Moore

Retrospective Theses and Dissertations

Reducing the noise radiated by internal combustion engine and electric powered rotary lawn mowers is becoming a topic of great concern among many members of the Outdoor Power Equipment Industry (OPEl). This concern has been fueled by a comprehensive legislative directive designed to limit the noise levels of outdoor power equipment sold to member states of the European Union (EU) has recently been issued. This directive will have a dramatic effect on the existing trade markets of both European and U.S. manufacturers and pose entry barriers for new markets because these limitations are believed to be beyond the present ...


Molecular-Level Modeling Of The Viscoelasticity Of Crosslinked Polymers: Effect Of Time And Temperature, P. P. Simon, Harry J. Ploehn Jan 1997

Molecular-Level Modeling Of The Viscoelasticity Of Crosslinked Polymers: Effect Of Time And Temperature, P. P. Simon, Harry J. Ploehn

Faculty Publications

We present a new molecular-level picture of chain dynamics for describing the viscoelasticity of crosslinked polymers. The associated mathematical model consists of a time-dependent momentum balance on a representative polymer segment in the crosslinked network, plus phenomenological expressions for forces acting on the segments. These include a cohesive force that accounts for intermolecular attraction, an entropic force describing the thermodynamics governing chain conformations, and a frictional force that captures the temperature dependence of relative chain motion. We treat the case of oscillatory uniaxial deformation. Solution of the model equations in the frequency domain yields the dynamic moduli as functions of ...


An Investigation Of Mechanical Properties Of Composites Containing Recycled Rubber Particles, Ryan C. Archey Jan 1997

An Investigation Of Mechanical Properties Of Composites Containing Recycled Rubber Particles, Ryan C. Archey

Masters Theses

In order to promote applications of recycled automobile tires, composite materials of recycled rubber tire particles with ethylene co-vinyl acetate (EVA), polybutadiene (PB), and Primacor were studied in the thesis. The composites were processed using a single screw extruder and a pelletizer. Compression molding was used to form specimens for hardness and impact tests. Mechanical properties of the composites were investigated in terms of tensile strength, percent elongation, Durometer hardness, and impact energy.

In this study, the content of recycled rubber was between 0 and 40 percent. Various matrices were processed using a combination of EVA, PB, or Primacor to ...


Part Form Errors Predicted From Machine Tool Performance Measurements, R. G. Wilhelm, N. Srinivasan, F. Farabaugh, R. Hocken Jan 1997

Part Form Errors Predicted From Machine Tool Performance Measurements, R. G. Wilhelm, N. Srinivasan, F. Farabaugh, R. Hocken

Mechanical & Materials Engineering Faculty Publications

Machine tool performance testing, as defined by IS0 230 and ANSI B5.54 has been successfully used to maintain and improve the accuracy and repeatability of production-level machine tools. In this study, a controlled series of experiments have been used to test the efficacy of these performance tests in the prediction of part form errors. Results are shown for flatness, squareness, position, and profile tolerances. The experimental results suggest that standard machine tool performance tests can also be used to predict the “best-case” tolerances that can be achieved for particular part features.