Solid Lubrication Mechanisms in Laser Deposited Nickel-titanium-carbon Metal Matrix Composites

Solid Lubrication Mechanisms in Laser Deposited Nickel-titanium-carbon Metal Matrix Composites

Date: December 2012
Creator: Mogonye, Jon-Erik
Description: A Ni/TiC/C metal matrix composite (MMC) has been processed using the laser engineered net shaping (LENS) process from commercially available powders with a Ni-3Ti-20C (atomic %) composition. This processing route produces the in-situ formation of homogeneously distributed eutectic and primary titanium carbide and graphite precipitates throughout the Ni matrix. The composite exhibits promising tribological properties when tested in dry sliding conditions with a low steady state coefficient of friction (CoF) of ~0.1 and lower wear rates in comparison to LENS deposited pure Ni. The as deposited and tribologically worn composite has been characterized using Auger electron spectroscopy, scanning electron microscopy (SEM), X-ray diffraction, high resolution transmission electron microscopy (HRTEM) with energy dispersive spectroscopy (EDS), dual beam focused ion beam SEM (FIB/SEM) serial sectioning and Vickers micro-hardness testing. The evolution of subsurface stress states and precipitate motion during repeated sliding contact has been investigated using finite element analysis (FEA). The results of FIB/SEM serial sectioning, HRTEM, and Auger electron spectroscopy in conjunction with FEA simulations reveal that the improved tribological behavior is due to the in-situ formation of a low interfacial shear strength amorphous carbon tribofilm that is extruded to the surface via refined Ni grain boundaries.
Contributing Partner: UNT Libraries
Perceptions of Disaster Professionalism in Mexico: Adding a New Public Management Perspective to Emergency Management

Perceptions of Disaster Professionalism in Mexico: Adding a New Public Management Perspective to Emergency Management

Date: August 2010
Creator: Urby, Heriberto, Jr.
Description: This study investigated the perceptions of emergency managers regarding the degree of emergency management professionalism in Mexico and how it can be improved. The disaster of the Mexico City earthquake of 1985 was used as the starting point for this case study, as the prospects for more-frequent and more-intense disasters lend credence to the need for improved professionalism and, thus, effectiveness among emergency managers in the future. An expansive framework of emergency management professionalism mechanisms (or characteristics) and an additional compilation of new public management components (or values) were devised from the extant literatures found within the respective emergency management and public administration fields. The theory advanced by this study is that by integrating new public management components with emergency management mechanisms, professionalism in Mexico will improve and, thus, emergency managers will become more effective. ualitative field research was the methodology employed and it included interviews with 35 emergency managers in Mexico in corroboration with documentary evidence, to ascertain emergency managers' perceptions of professionalism in Mexico. The findings of this study determined that emergency managers in Mexico are implementing many of the mechanisms of professionalism but fewer new public management components. This study posits that by integrating new public management ...
Contributing Partner: UNT Libraries
Ptᴵᴵ-Catalyzed Ethylene Hydrophenylation: Influence of Dipyridyl Chelate RIng Size on Catalyst Activity and Longevity

Ptᴵᴵ-Catalyzed Ethylene Hydrophenylation: Influence of Dipyridyl Chelate RIng Size on Catalyst Activity and Longevity

Date: May 3, 2013
Creator: McKeown, Bradley A.; Gonzalez, Hector Emanuel; Gunnoe, T. Brent; Cundari, Thomas R., 1964- & Sabat, Michal
Description: Article discussing Ptᴵᴵ-catalyzed ethylene hydrophenylation.
Contributing Partner: UNT College of Arts and Sciences
Current Applications of Computational Chemistry in JACS - Molecules, Mechanisms, and Materials

Current Applications of Computational Chemistry in JACS - Molecules, Mechanisms, and Materials

Date: September 21, 2011
Creator: Borden, Weston T., 1943-
Description: Article discussing molecules, mechanisms, and materials and current applications of computational chemistry in the Journal of the American Chemical Society (JACS).
Contributing Partner: UNT College of Arts and Sciences
Thermodynamics, Kinetics, and Mechanism of (silox)3M(olefin) to (silox)3M(alkylidene) Rearrangements (silox = tBu3SiO; M = Nb, Ta)

Thermodynamics, Kinetics, and Mechanism of (silox)3M(olefin) to (silox)3M(alkylidene) Rearrangements (silox = tBu3SiO; M = Nb, Ta)

Date: March 10, 2005
Creator: Hirsekorn, Kurt F.; Veige, Adam S.; Marshak, Michael P.; Koldobskaya, Yelena; Wolczanski, Peter T.; Cundari, Thomas R., 1964- et al.
Description: Article discussing the thermodynamic, kinetic, and mechanism of (silox)3M(olefin) to (silox)3M(alkylidene) rearrangements (silox = tBu3SiO; M = Nb, Ta).
Contributing Partner: UNT College of Arts and Sciences