In situ diagnostics and prognostics of solder fatigue in IGBT modules for electric vehicle drives

This paper proposes an in situ diagnostic and prognostic (D&P) technology to monitor the health condition of insulated gate bipolar transistors (IGBTs) used in EVs with a focus on the IGBTs' solder layer fatigue. IGBTs' thermal impedance and the junction temperature can be used as health indicators for through-life condition monitoring (CM) where the terminal characteristics are measured and the devices' internal temperature-sensitive parameters are employed as temperature sensors to estimate the junction temperature. An auxiliary power supply unit, which can be converted from the battery's 12-V dc supply, provides power to the in situ test circuits and CM data can be stored in the on-board data-logger for further offline analysis. The proposed method is experimentally validated on the developed test circuitry and also compared with finite-element thermoelectrical simulation. The test results from thermal cycling are also compared with acoustic microscope and thermal images. The developed circuitry is proved to be effective to detect solder fatigue while each IGBT in the converter can be examined sequentially during red-light stopping or services. The D&P circuitry can utilize existing on-board hardware and be embedded in the IGBT's gate drive unit.

Reliability-based calibration for a mechanics-based fatigue cracking design procedure

Most pavement design procedures incorporate reliability to account for design inputs-associated uncertainty and variability effect on predicted performance. The load and resistance factor design (LRFD) procedure, which delivers economical section while considering design inputs variability separately, has been recognised as an effective tool to incorporate reliability into design procedures. This paper presents a new reliability-based calibration in LRFD format for a mechanics-based fatigue cracking analysis framework. This paper employs a two-component reliability analysis methodology that utilises a central composite design-based response surface approach and a first-order reliability method. The reliability calibration was achieved based on a number of field pavement sections that have well-documented performance history and high-quality field and laboratory data. The effectiveness of the developed LRFD procedure was evaluated by performing pavement designs of various target reliabilities and design conditions. The result shows an excellent agreement between the target and actual reliabilities. Furthermore, it is clear from the results that more design features need to be included in the reliability calibration to minimise the deviation of the actual reliability from the target reliability.

Dynamic Behavior and Fatigue Life of Highway Bridges Due to Doubling Heavy Vehicles

An increase in the demand for the freight shipping in the United States has been predicted for the near future and Longer Combination Vehicles (LCVs), which can carry more loads in each trip, seem like a good solution for the problem. Currently, utilizing LCVs is not permitted in most states of the US and little research has been conducted on the effects of these heavy vehicles on the roads and bridges. In this research, efforts are made to study these effects by comparing the dynamic and fatigue effects of LCVs with more common trucks. Ten Steel and prestressed concrete bridges with span lengths ranging from 30’ to 140’ are designed and modeled using the grid system in MATLAB. Additionally, three more real bridges including two single span simply supported steel bridges and a three span continuous steel bridge are modeled using the same MATLAB code. The equations of motion of three LCVs as well as eight other trucks are derived and these vehicles are subjected to different road surface conditions and bumps on the roads and the designed and real bridges. By forming the bridge equations of motion using the mass, stiffness and damping matrices and considering the interaction between the truck and the bridge, the differential equations are solved using the ODE solver in MATLAB and the results of the forces in tires as well as the deflections and moments in the bridge members are obtained. The results of this study show that for most of the bridges, LCVs result in the smallest values of Dynamic Amplification Factor (DAF) whereas the Single Unit Trucks cause the highest values of DAF when traveling on the bridges. Also in most cases, the values of DAF are observed to be smaller than the 33% threshold suggested by the design code. Additionally, fatigue analysis of the bridges in this study confirms that by replacing the current truck traffic with higher capacity LCVs, in most cases, the remaining fatigue life of the bridge is only slightly decreased which means that taking advantage of these larger vehicles can be a viable option for decision makers.

Determining Pathways to Improvements in Fatigue in Rheumatoid Arthritis : Results From the British Society for Rheumatology Biologics Register for Rheumatoid Arthritis

Funded by: The Institute of Applied Health Sciences, University of Aberdeen The British Society for Rheumatology Biologics Register for Rheumatoid Arthritis British Society for Rheumatology to the University of Manchester Schering-Plough Wyeth Laboratories Abbott Laboratories Amgen

Determining Pathways to Improvements in Fatigue in Rheumatoid Arthritis : Results From the British Society for Rheumatology Biologics Register for Rheumatoid Arthritis

Funded by: The Institute of Applied Health Sciences, University of Aberdeen The British Society for Rheumatology Biologics Register for Rheumatoid Arthritis British Society for Rheumatology to the University of Manchester Schering-Plough Wyeth Laboratories Abbott Laboratories Amgen

The Longitudinal Course of Fatigue in Rheumatoid Arthritis : Results from the Norfolk Arthritis Register

Acknowledgment: The authors would like to thank the University of Manchester for access to the Norfolk Arthritis Register data and Professor Deborah Symmons for comments on an earlier draft of the manuscript. K.L.D. is funded by a studentship from the Institute of Applied Health Sciences, University of Aberdeen.

The changes in pain which mediate Reductions in fatigue likely reflect central not peripheral mechanisms : Results from the BSRBR-RA

Peer reviewed

Fatigue is associated with excess mortality in the general population : results from the EPIC-Norfolk study

This work was supported by programme grants from the Medical Research Council G1000143 and the Cancer Research UK 8257. Funders have no roles in study design, analysis, and interpretation of the findings.

Determining Pathways to Improvements in Fatigue in Rheumatoid Arthritis : Results From the British Society for Rheumatology Biologics Register for Rheumatoid Arthritis

Funded by: The Institute of Applied Health Sciences, University of Aberdeen The British Society for Rheumatology Biologics Register for Rheumatoid Arthritis British Society for Rheumatology to the University of Manchester Schering-Plough Wyeth Laboratories Abbott Laboratories Amgen

La signification de la qualité de vie de mères ayant un enfant atteint de dystrophie musculaire de Duchenne, traité au déflazacort

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

La fonction musculaire du plancher pelvien chez les femmes continentes et atteintes d'incontinence urinaire à l'effort

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Asymétrie et faiblesse musculaire lors des tâches de se lever et de s'asseoir chez l'adulte avec une hémiparésie

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Fils orthodontiques esthétiques : résistance en fatigue et résistance de la coloration

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Études du métabolisme cérébral et musculaire lors d'une insuffisance hépatique aiguë : implications pour de nouvelles stratégies thérapeutiques

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Caractérisation génétique d'un effet fondateur du sud-ouest du Québec : une nouvelle forme de dystrophie musculaire des ceintures

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.