Effect of substrate surface roughening and cold spray coating on the fatigue life of AA2024 specimens

The effects of cold spray coating and substrate surface preparation on crack initiation under cyclic loading have been studied on Al2024 alloy specimens. Commercially pure (CP) aluminum feedstock powder has been deposited on Al2024-T351 samples using a cold-spray coating technique known as high velocity particle consolidation. Substrate specimens were prepared by surface grit blasting or shot peening prior to coating. The fatigue behavior of both coated and uncoated specimens was then tested under rotating bend conditions at two stress levels, 180 MPa and 210 MPa. Scanning electron microscopy was used to analyze failure surfaces and identify failure mechanisms. The results indicate that the fatigue strength was significantly improved on average, up to 50% at 180 MPa and up to 38% at 210 MPa, by the deposition of the cold-sprayed CP-Al coatings. Coated specimens first prepared by glass bead grit blasting experienced the largest average increase in fatigue life over bare specimens. The results display a strong dependency of the fatigue strength on the surface preparation and cold spray parameters

Exploring the Life of Edith Fetherston through her Clothing

This research is an examination of the life of Edith Fetherston through studying her clothing and comparing her clothes to fashion history. The authors of Survey of Historic Costume, Tortora and Eubank, state that: 'Dress serves as a means of communication,' and that 'historic dress provides readers with some context for the period in which costumes were worn'. Most importantly, they state that clothing is 'a glimpse of attitudes and values as they were expressed by individuals of [a] period.' (4). Studying clothing history is a way to understand the attitudes of the times; it has a relationship with the attitudes of the society in which it is or was worn. Studying garments can identify personalities, as well as professions, and economic status. My research is based on the wardrobe of Edith Fetherston between the early twenties and late sixties. This thesis begins by examining Edith herself, then it examines each decade and its major characteristics, and finally my research examines at least two garments from each of the five decades.