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American Indian Homicide; A County Level Analysis Utilizing Social Disorganization Theory Revisted
Title
American Indian Homicide; A County Level Analysis Utilizing Social Disorganization Theory Revisted.
Creator
Ward, Kayla, Reckdenwald, Amy, Gay, David, Corzine, Harold, University of Central Florida
Abstract / Description
Lanier and Huff-Corzine's (2006) article (")American Indian Homicide: A County-Level Analysis Utilizing Social Disorganization Theory(") has been referred to as a highly influential piece of literature on American Indian homicide. The study looked at American Indian homicide victimization incidents by county between 1986 and 1992 in the continental United States using the framework of social disorganization theory. Despite the violent crime drop in the 1990s, little research exists that...
Show moreLanier and Huff-Corzine's (2006) article (")American Indian Homicide: A County-Level Analysis Utilizing Social Disorganization Theory(") has been referred to as a highly influential piece of literature on American Indian homicide. The study looked at American Indian homicide victimization incidents by county between 1986 and 1992 in the continental United States using the framework of social disorganization theory. Despite the violent crime drop in the 1990s, little research exists that examines current dynamics of American Indian homicide. This study provides an updated replication of Lanier and Huff-Corzine (2006) by examining the impact of social disorganization on American Indian homicide victimization between 2006 and 2012. Results differ from Lanier and Huff-Corzine (2006). Reasons for the different outcomes are explored and implications for future research are discussed.
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Date Issued
2015
Identifier
CFE0005902, ucf:50865
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0005902
Graphene Oxide Reinforcement in Plasma Sprayed Nickel-5%Aluminum Coatings
Title
Graphene Oxide Reinforcement in Plasma Sprayed Nickel-5%Aluminum Coatings.
Creator
Ward, David, Seal, Sudipta, Vaidyanathan, Raj, Heinrich, Helge, Zhai, Lei, University of Central Florida
Abstract / Description
Metallic plasma sprayed coatings are widely used in the aerospace industry for repair on worn engine components. However, the inherent defects in these coatings limit the variety of repairs and reduce the service life of the repaired parts. A potential solution to overcome this problem is to mix small amounts of inexpensive graphene oxide in the powder feedstock. The incredible strength to weight ratio of graphene oxide makes it a viable additive to improve mechanical properties of metallic...
Show moreMetallic plasma sprayed coatings are widely used in the aerospace industry for repair on worn engine components. However, the inherent defects in these coatings limit the variety of repairs and reduce the service life of the repaired parts. A potential solution to overcome this problem is to mix small amounts of inexpensive graphene oxide in the powder feedstock. The incredible strength to weight ratio of graphene oxide makes it a viable additive to improve mechanical properties of metallic plasma sprayed coatings. The powder system chosen for this research is Nickel-5Aluminum since it is a common coating for such repairs. The greatest challenge was retaining graphene oxide, which combusts at 400(&)deg;C, while melting the Nickel above 1450(&)deg;C using a high temperature plasma plume. Graphene oxide was successfully retained in the coatings using either of two configurations: (1) Injecting the graphene oxide powder via solution suspension separately from the metal powder, or (2) Installing a shroud on the front of the plasma gun and backfilling with Argon to inhibit combustion. The uniquely designed solution suspension configuration resulted in a higher deposition efficiency of graphene oxide while the inert shroud configuration had a more homogeneous distribution and retention of graphene oxide in the coatings. The best overall coating was achieved using the inert shroud configuration using a powder mixture containing 2% weight Edge Functionalized Graphene Oxide. Vickers microhardness increased 46% and tensile adhesion strength increased 26% over control samples. This is possible due to the mechanisms of dislocation strengthening and stress transfer previously reported in graphene oxide reinforced Aluminum composites formed by flake powder metallurgy. It was also observed that the energy released by the combustion of graphene oxide helps to uniformly melt the Nickel particles and improve the coating microstructure, allowing for more forgiving spray parameters. The methods developed and results attained in this research open opportunities for graphene oxide to be added as inexpensive reinforcements to other metallic compositions for widespread use in metal matrix composite manufacturing.
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Date Issued
2014
Identifier
CFE0005901, ucf:50857
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0005901