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Materials Degradation in Mechanical Design Wear, Corrosion, Fatigue and their Interactions

Materials degradation from environmental conditions is a common factor that will often occur in mechanical equipment used in every type of environment. These processes can frequently materialize in unpredicted and harmful ways, especially when they interact and lead to early component damage or failure. This five-session course will summarize the mechanisms that cause materials and mechanical components to degrade in service through exposure to deleterious mechanical and environmental conditions.
Training / Education

Fuel Systems Material Selection and Compatibility with Alternative Fuels

This course will introduce the participants to the factors governing fuel-material compatibility and methods to predict and empirically determine compatibility for new alternative fuel chemistries.  By understanding the mechanisms and factors associated with chemically-induced degradation, participants will be able to assess the impact of fuel chemistry to infrastructure components, including those associated with vehicle fuel systems.  This course is unique in that it looks at compatibility from a fuel chemistry perspective, especially new fuel types such as alcohols and other biofuels. 
Technical Paper

Effects of In-cylinder flow structures on soot formation and oxidation in a swirl-supported light-duty diesel engine

In this paper, computation fluid dynamics (CFD) simulations are performed to describe the effect of in-cylinder flow structures on the formation and oxidation of soot in a swirl-supported light-duty diesel engine. The focus of the paper is on the effect of swirl motion and injection pressure on late cycle soot oxidation. The structure of the flow at different swirl numbers is studied to investigate the effect that varying swirl number imposes on the coherent flow structures. These coherent flow structures are studied to understand the mechanism that leads to efficient soot oxidation in late cycle. Effect of varying injection pressure at different swirl numbers and the interaction between spray and swirl motions are discussed. The complexity of diesel combustion, especially when soot and other emissions are of interest, requires using a detailed chemical mechanism to have a correct estimation of temperature and species distribution.
Technical Paper

Reactivity Analysis and Modeling of NOx purification Considering Reactions on Cu active sites and Brønsted acid sites in a Cu-chabazite SCR catalyst

In this study, the NOx purification reactivity of a Cu-chabazite SCR catalyst was analyzed over a wide temperature range based on the NH3-SCR mechanism considering Cu redox reactions and reactions on a Brønsted acid site. It was revealed that the De-NOx reactions on the active site of Cu proceeded in different paths at lower and higher temperatures. This means that the rate-limiting step of SCR reactions was changed as each temperature. The reaction rate of NOx purification on a Cu site less than 200 °C was determined by the reaction rate of oxidation of Cu sites. On the other hand, the NH3 adsorption on Cu sites played a dominant role in NOx purification at temperature range higher than 300°C. Moreover, it was also observed that the Cu reaction site took different states at low and high temperatures during the NOx purification and was estimated that the valence state of a Cu site was changed as the temperature increased.
Technical Paper

Analysis of TWC operation characteristics in a Euro6 gasoline light duty vehicle

A Euro6 gasoline light duty vehicle has been tested at the engine dynamometer and the emissions have been analyzed upstream and downstream the Three-Way-Catalyst (TWC) during the WLTP cycle. Catalyst simulations have been used for assessing the processes inside the catalytic converter using a reaction scheme based on 19 brutto reactions (Direct oxidation and reduction, selective catalytic re-ductions with CO, C3H6 and H2, steam reforming, water-gas shift and bulk Ceria as well as surface Ce-ria reactions). The reactions have been parametrized in order to best approximate the measurements. Based on the reactions taken into account, the real vehicle emissions can be predicted with good accu-racy. The simulations show that the cycle emissions are comprising mainly by the cold start contribution as well as discrete emission break-through events during transients.

Magnesium Alloys in Aircraft Seats - Engineering Design and Fabrication Recommended Practices

This document is a guide to the application of magnesium alloys to aircraft interior components including but not limited to aircraft seats. It provides background information on magnesium, its alloys and readily available forms such as extrusions and plate. It also contains guidelines for “enabling technologies” for the application of magnesium to engineering solutions including: machining, joining, forming, cutting, surface treatment, flammability issues, and designing from aluminum to magnesium.
Technical Paper

Fault Feature Extraction of Elliptically Shaped Bearing Raceway

The elliptically shaped bearing (ESB) with a rigid, elliptical inner race and a flexible, thin-walled outer race is the most easily damaged core component of harmonic drive. The ESB rotates under cycle load of alternating stress due to its special elliptic structure. Hence, the fault features of ESB such as fatigue spalling and pitting are apt to be concealed by the excitation of impulses caused by alternating between major axis and minor axis. In order to diagnose the fault on raceway surfaces of ESB, a new method of CMWT-FH based on Continuous Morlet Wavelet Transform (CMWT) and FFT-based Hilbert (FH) spectrum analysis is proposed to extract the fault feature.