Universal Technical Institute

About: Universal Technical Institute is a education organization based out in Scottsdale, Arizona, United States. It is known for research contribution in the topics: Carbon nanotube & Thermal conductivity. The organization has 226 authors who have published 468 publications receiving 11280 citations. The organization is also known as: UTI & Universal Technical Institute of Phoenix.

A high frequency photodriven polymer oscillator

Abstract: High frequency and large amplitude oscillations are driven by laser exposure in cantilevers made from a photosensitive liquid crystal polymer.

Optimal Control of Shock Wave Turbulent Boundary Layer Interactions Using Micro-Array Actuation

Abstract: The intent of this study on micro-array flow control is to demonstrate the viability and economy of Response Surface Methodology (RSM) to determine optimal designs of micro-array actuation for controlling the shock wave turbulent boundary layer interactions within supersonic inlets and compare these concepts to conventional bleed performance. The term micro-array refers to micro-actuator arrays which have heights of 25 to 40 percent of the undisturbed supersonic boundary layer thickness. This study covers optimal control of shock wave turbulent boundary layer interactions using standard micro-vane, tapered micro-vane, and standard micro-ramp arrays at a free stream Mach number of 2.0. The effectiveness of the three micro-array devices was tested using a shock pressure rise induced by the 10 shock generator, which was sufficiently strong as to separate the turbulent supersonic boundary layer. The overall design purpose of the micro-arrays was to alter the properties of the supersonic boundary layer by introducing a cascade of counter-rotating micro-vortices in the near wall region. In this manner, the impact of the shock wave boundary layer (SWBL) interaction on the main flow field was minimized without boundary bleed.

Polyethylene glycol functionalized dicationic ionic liquids with alkyl or polyfluoroalkyl substituents as high temperature lubricants

Abstract: A series of new polyethylene glycol functionalized dicationic ionic liquids with alkyl or polyfluoroalkyl substitutents (9–17 and 19–24) has been prepared. Important physical properties of these liquids, including glass transition (Tg) and decomposition temperatures (Td), solubility in common solvents, density (d) and viscosity (η), were measured. These ionic liquids show high thermal stability and good lubricity. In general, imidazolium based dicationic liquids have higher Td (>415 °C) than their triazolium analogues. The introduction of polyfluoroalkyl groups boosts antiwear properties but also leads to a decrease in Td. These ionic liquids also exhibit excellent tribological characteristics even at 300 °C, which suggests use as high temperature lubricants.

Strain hardening due to deformation twinning in α-titanium: Mechanisms

Abstract: Novel experiments were conducted to elucidate the effect of deformation twinning on the mechanical response of high-purity α-titanium deformed at room temperature. Orientation-imaging microscopy (OIM), microhardness, and nanohardness evaluations were employed in conjunction with optical microscopy and quasi-static compression testing to obtain insight into the deformation mechanisms. Hardness measurements revealed that the newly formed deformation twins were harder than the matrix. This observation is perhaps the first experimental evidence for the Basinski mechanism for hardening associated with twinning, arising from the transition of glissile dislocations to a sessile configuration upon the lattice reorientation by twinning shear. This work also provided direct evidence for two competing effects of deformation twinning on the overall stress-strain response: (1) hardening via both a reduction of the effective slip length (Hall-Petch effect) and an increase in the hardness of twinned regions (Basinski mechanism) and (2) softening due to the lattice reorientation of the twinned regions.