La combustion sans flamme est un mode de combustion innovant dans le domaine des économies d'énergie et de la réduction des émissions polluantes, qui reste toutefois encore peu étudié. L'objectif de cette étude est de caractériser ces mécanismes par une étude expérimentale. La première étape de cette étude a été réalisée sur une installation d'essais semi-industrielle. Différents moyens de mesure dans la flamme ont été utilisés pour caractériser le mode d'accrochage de la flamme, la structure des zones de réactives, les recirculations des produits de combustion et leur impact sur la combustion et les émissions polluantes. Parallèlement, une installation d'essais de laboratoire à été mise en place. La caractéristique essentielle de cette installation est la possibilité de changer une des dimensions de la chambre tout en gardant identiques les conditions opératoires. Différents paramètres (puissance, température de l'air, température des parois, taux d'aération, confinement de la flamme) sont modifiés afin de caractériser leur impact sur le régime de combustion sans flamme. <br />Les résultats montrent que la flamme peut être divisée en deux zones. Alors que la réaction principale se situe où le jet d'air et de gaz naturel se rejoignent, une première zone réactive est aussi observée dans la zone de recirculation interne, assurant la stabilisation de la flamme. La recirculation des produits de combustion est mise en évidence et quantifiée à partir des résultats des mesures dans la flamme. Entraînées par l'écoulement principal, ces recirculations induisent une importante dilution dans les zones réactives, où la concentration en CO et la température restent à de faibles niveaux. Les oxydes d'azote sont principalement produits par voie thermique, mais restent très faibles. Par ailleurs, un mécanisme de réduction dans la flamme des oxyde d'azote présents dans les recirculations peut être observé. L'étude paramétrique montre que si la puissance n'a pas d'influence sur le régime de combustion, la combustion sans flamme est possible avec de l'air non préchauffé. Par ailleurs, une augmentation du taux d'aération réduit la dilution de la zone réactive par les inertes. Pour de fortes augmentations du taux d'aération, on peut observer l'apparition d'une troisième zone de réaction à l'extérieur des jets de gaz naturel ; on quitte alors le régime de combustion sans flamme

A numerical study aimed at probabilistically assessing the coastal hazard posed by tsunamis induced by one-dimensional submarine rigid landslides that experience translational failure is presented. The numerical model here utilized is the finite-difference recreation of a linear, fully dispersive mild-slope equation model for wave generation and propagation. This recreated model has the capability to simulate submarine landslides that detach into multiple rigid pieces as failure occurs. An ad-hoc formulation describing the combined space-time coherency of the landslide is presented. Monte Carlo simulations are employed, with an emphasis on the shoreward-traveling waves, to construct probability of exceedance curves for the maximum dimensionless wave height from which wave statistics can be extracted. As inputs to the model, eight dimensionless parameters are specified both deterministically in the form of parameter spaces and probabilistically with normal distributions. Based on a sensitivity analysis, the results of this study indicate that submarine landslides with large width to thickness ratios and coherent failure behavior are most effective in generating tsunamis. Failures modes involving numerous slide pieces that fail in a very compact fashion, however, were observed to induce bigger waves than more coherent landslides. Rapid weakening in tsunami generation potential for some of the parameter combinations suggests that the hazard posed by submarine landslide tsunamis is strongly dependent on source features and local conditions and is only of concern for landslides of substantial dimensions.

Performance of two different waste heat recovery systems (one based on Rankine cycle and the other one using thermoelectricity) combined with non-hybrid, mild-hybrid and full hybrid systems are investigated. The vehicle under investigation was a 440hp Scania truck, loaded by 40 tons. Input data included logged data from a long haulage drive test in Sweden.All systems (waste heat recovery as well as hybrid) are implemented and simulated in Matlab/Simulink. Almost all systems are modeled using measured data or performance curves provided by one manufacturer. For Rankine system results from another investigation were used.Regardless of practical issues in implementing systems, reduction in fuel consumption for six different combination of waste heat recovery systems and hybrid systems with different degrees of hybridization are calculated. In general Rankine cycle shows a better performance. However, due to improvements achieved in laboratories, thermoelectricity could also be an option in future.This study focuses on “system” point of view and therefore high precision calculations is not included. However it can be useful in making decisions for further investigations.

In two separate studies, we used diffusion tensor imaging (DTI)to examine white matter changes secondary to traumatic brain injury (TBI) and spinal cord injury (SCI). The first study examined the utility of DTI for a single case diagnosis of mild TBI (mTBI) and demonstrated that the anterior limb of the internal capsule and the genu of the corpus callosum were sensitive and specific to mTBI. The second study examined the sub-acute effects of SCI on white matter tissue in the brain and demonstrated that SCI patients have a significantly greater degree of FA asymmetry than control subjects in the superior and posterior corona radiata. The first study has provided preliminary proof of principal evidence that DTI can be used to diagnose mTBI in individual cases. The second study suggests that the degree of asymmetry may be a useful biomarker for detecting subtle white matter changes.

Traumatic brain injury (TBI) is the leading cause of death and disability in the industrialized world. This pilot study investigated demographic, clinical and environmental factors associated with return to work (RTW) among workers who sustained a mild to moderate work-related TBI (WrTBI). Using a retrospective cohort design, participants were recruited through an outpatient clinic dedicated to evaluating injured workers after a WrTBI. A mailed survey and medical record abstraction tool were used for data collection. Of the 40 injured workers who participated in this study, 19 reported working at time of follow-up. Those who were unable to RTW scored significantly lower on measures of emotional well-being; there were no significant between-group differences in cognitive or physical impairments. Gradual RTW and workplace accommodations were reported as key factors facilitating RTW. Our findings provide information that addresses improved rehabilitation and management of WrTBI as well as better education and support for employers.

In two separate studies, we used diffusion tensor imaging (DTI)to examine white matter changes secondary to traumatic brain injury (TBI) and spinal cord injury (SCI). The first study examined the utility of DTI for a single case diagnosis of mild TBI (mTBI) and demonstrated that the anterior limb of the internal capsule and the genu of the corpus callosum were sensitive and specific to mTBI. The second study examined the sub-acute effects of SCI on white matter tissue in the brain and demonstrated that SCI patients have a significantly greater degree of FA asymmetry than control subjects in the superior and posterior corona radiata. The first study has provided preliminary proof of principal evidence that DTI can be used to diagnose mTBI in individual cases. The second study suggests that the degree of asymmetry may be a useful biomarker for detecting subtle white matter changes.

Traumatic brain injury (TBI) is the leading cause of death and disability in the industrialized world. This pilot study investigated demographic, clinical and environmental factors associated with return to work (RTW) among workers who sustained a mild to moderate work-related TBI (WrTBI). Using a retrospective cohort design, participants were recruited through an outpatient clinic dedicated to evaluating injured workers after a WrTBI. A mailed survey and medical record abstraction tool were used for data collection. Of the 40 injured workers who participated in this study, 19 reported working at time of follow-up. Those who were unable to RTW scored significantly lower on measures of emotional well-being; there were no significant between-group differences in cognitive or physical impairments. Gradual RTW and workplace accommodations were reported as key factors facilitating RTW. Our findings provide information that addresses improved rehabilitation and management of WrTBI as well as better education and support for employers.

The structure of phonological processing for typically developing children has been debated over the past two decades. Recent research has indicated that phonological processing is best explained by a single underlying phonological ability (e.g., Anthony and Lonigan, 2004). The current study had two goals. The first goal was to determine the structure of phonological processing for school-age children with mild intellectual disabilities (MID). The second goal was to determine the relationship between the components of phonological processing and expressive and receptive language ability. The participants were 222 school-age children identified by their schools as having MID. Confirmatory factor analysis was utilized to determine the structure of phonological processing. The results indicated that a model with one phonological awareness factor and one naming speed factor explained the data better than competing models with a single latent factor or more than two latent factors. There was a negative significant relationship between phonological processing and naming speed. There were positive bivariate relationships between phonological processing and expressive and receptive language. There were negative bivariate relationships between naming speed and expressive and receptive language. These results are consistent with other research findings with typically developing children, indicating a similarity in the relationships between phonological process and language for children with MID. Theoretical and instructional implications are discussed.

Deficiencies in mathematics skill constrain students’ educational achievement and subsequently, their employment outcomes. This study included 265 school-identified students with mild intellectual disabilities. The research questions investigated the extent to which phonological awareness, color naming speed, and vocabulary knowledge, was related to mathematics skill after controlling for grade level via regression analyses. Further, the mediating effects of expressive vocabulary on the relationship between receptive vocabulary and mathematics skill as well as the indirect effect of receptive vocabulary knowledge on mathematics skill through expressive vocabulary were examined. The findings indicated that after controlling for grade level, phonological awareness, naming speed, and vocabulary knowledge were significantly related to mathematics skill. The mediating effects of expressive vocabulary as well as the indirect effects of receptive vocabulary knowledge on mathematics skill were also significant.

It has been assumed that mathematics testing indicates the development of mathematics concepts, but the linguistic demands of assessment have not been evaluated, especially for children with mild intellectual disabilities. 244 children (grades 2 – 5) were recruited from a larger reading intervention study. Using a multilevel longitudinal SEM model, baseline and post-intervention time points were examined for the contribution of item linguistic complexity, child language skills, and their potential interaction in predicting item level mathematics assessment performance. Item linguistic complexity was an important, stable, and negative predictor of mathematics achievement with children’s language skills significantly and positively predicting mathematics achievement. The interaction between item linguistic complexity and language skills was significant though not stable across time. Following intervention, children with higher language skills performed better on linguistically complex mathematics items. Mathematics achievement may be related to an interaction between children’s language skills and the linguistic demands of the tests themselves.