Enhancement of aeroelastic rotor airload prediction methods

The accurate prediction of rotor air loads is a current topic of interest in the rotorcraft community. The complex nature of this loading makes this problem especially difficult. Some of the issues that must be considered include transonic effects on the advancing blade, dynamic stall effects on the retreating blade, and wake vortex interactions with the blades, fuselage, and other components. There are numerous codes to perform these predictions, both aerodynamic and structural, but until recently each code has refined either the structural or aerodynamic aspect of the analysis without serious consideration to the other, using only simplified modules to represent the physics. More recent research has concentrated on combining high fidelity CFD and CSD computations to be able to use the most accurate codes available to compute both the structural and the aerodynamic aspects. The objective of the research is to both evaluate and extend a range of prediction methods comparing both accuracy and computational expense. This range covers many methods where the highest accuracy method shown is a delta loads coupling between an unstructured CFD code and a comprehensive code, and the lowest accuracy, but highest efficiency, is found through a free wake and comprehensive code coupling using simplified 2D aerodynamics. From here methods to improve the efficiency and accuracy of the CFD code will be considered through implementation of steady-state grid adaptation, a time accurate low Mach number preconditioning method, and the use of fully articulated rigid blade motion. The exact formulation of the 2D aerodynamic model used in the CSD code will be evaluated, as will efficiency improvements to the free wake code. The advantages of the free-wake code will be tested against a dynamic inflow model. A comparison of all of these methods will show the advantages and consequences of each combination, including the types of physics that each method is able to, or not able to, capture through examination of how closely each method matches flight test data.Ph.D.Committee Chair: Smith, Marilyn; Committee Member: Bauchau, Olivier; Committee Member: Costello, Mark; Committee Member: Moulton, Marvin; Committee Member: Ruffin, Stephe

The rise and fall of institutional entrepreneurship in Islamic financial reporting standardisation projects

This paper explores the institutional entrepreneurship process. It focuses on how institutional entrepreneurs implement their vision of accounting change in the Islamic financial reporting standardisation initiatives while providing insights into why these actors may fail in this process. Research findings informed by semi-structured interviews and document analysis demonstrate that institutional entrepreneurs’ attainment of accounting change is subject to their ability to collectively and skilfully frame, promote and institutionalise their entrepreneurial vision, mobilise allies and alleviate the resistance of field’s “incumbents”. The paper contributes to the accounting change literature by expanding our understanding of the determinants of successful accounting change and of how institutional entrepreneurs can effect change in the contemporary accounting system. It also contributes to the ongoing institutional entrepreneurship theorisation by revealing the contingencies through which actors may overcome the barriers to change in highly institutionalised systems

Designing specialized technology to aid assistance dogs

Interest is growing in studying canine and human relationships, especially working canines and their role in society. Interest is also growing in designing informed, user centered interactive technologies for animals. Combining these two themes, my doctoral research looks at creating user-centered, ethnographically informed designs for working animals (working dogs). The work examines existing design methodologies and posits new ones to contribute to a wider Animal-Computer Interaction (ACI) framework to design for and with animal users. Here I review the initial findings of the on-going work to develop an emergency alert alarm for assistance dog use

Perspectives d'amélioration du conseil prévisionnel de fertilisation azotée à la parcelle en Wallonie par l'utilisation du logiciel AzoFert®

Prospects for improving the provisional nitrogen fertilization recommendation at field scale in Wallonia using the AzoFert® software. The French software AzoFert® for nitrogen fertilization recommendation is currently under adaptation and validation for soil and climatic conditions in Wallonia by the CRA-W within the INTERREG IV project "SUN" (Sustainable Use of Nitrogen). This adaptation has raised the need for a change of values in the parameter tables and catalogs relating to meadow residues, crop residues, catch crop practices, crops, organic amendments and soil type. Data from 25 trials of increasing nitrogen fertilizer rates conducted by CRA-W between 1996 and 2011 in cereal, potato and vegetable crops located on loam and sandy loam soil were used to validate the AzoFert® software adapted for Wallonia. The difference between nitrogen rates recommended on the one hand by AzoFert® or Azobil® (software currently used in the reference lab for Nitrate [Requasud] at CRA-W) and the optimal dose of nitrogen fertilizer assessed in each trial on the other hand shows that, in most cases, AzoFert® gives a recommendation closer to the optimum than Azobil®. The nitrogen uptake measured in the plants collected in the unfertilized control plot also shows a higher correlation with nitrogen supply from the soil assessed by AzoFert® than for plants assessed by Azobil®. The more accurate estimate of the mineralization of organic sources, probably linked to the dynamic soil nitrogen supply approach integrated into AzoFert®, may explain the gain in the greater accuracy of the AzoFert® recommendation in comparison with that of Azobil®

DURAÇÃO E TAXA DE SAÍDA DO DESEMPREGO: EVIDÊNCIAS DE AUSÊNCIA DE DEPENDÊNCIA NA DURAÇÃO PARA AS REGIÕES METROPOLITANAS DO BRASIL (1984-2000)

The proportion of long-term unemployed (6 or more months) in the six major metropolitan areas in Brazil has grown 72% between 1986 and 2000. At the same time, the average duration of unemployment has risen 43% for the same period. This worrisome information motivates our purpose in this work: study the relation between exit probabilities and unemployment duration. Former studies for Brazil have found a negative relation between those two variables, considered the effect of the existence of a negative unemployment duration dependence. We try to respond below to what extent this is due to the heterogeneity of the unemployment group and to what extent to a true effect of duration dependence, being that question most relevant for policy-oriented decisions. In order to evaluate this matter, we uses the eyeball test proposed in Jackman and Layard (1991) applied to PME data (1984 to 2000). This test analyzes the impact of the average duration variation along the years on the probability of leaving unemployment for different duration classes, separating the effect of heterogeneity from genuine duration dependence. The results contradict former studies for Brazil since we consider that the fall in exit probabilities raises with unemployment duration due to the effect of heterogeneity of unemployed in observed and unobserved characteristics and not to unemployment negative duration dependence. Nevertheless, our findings are in accordance with studies for developed economies, with exception for England.