Multitasking in background noise may involve greater cognitive processing demands than multitasking in quiet due to an increase in perceptual demands (Rabbitt, 1968; Pichora-Fuller & Schneider, 2000). This study investigated the effect of background noise in the listening environment on the ability of young adults with normal hearing and older adults with sensorineural hearing loss to perceive speech while performing a secondary task. A dual task paradigm, which included word recognition and visual serial recall, was used to examine ability to divide limited processing resources between two tasks. The number of digits to be recalled was varied in order to test the hypothesis that background noise would degrade multitasking abilities to a greater degree than in quiet for more difficult tasks. Participants included 37 native English speakers between 19-25 years of age with pure-tone thresholds better than or equal to 20 dB HL and 10 English speakers between 58-85 years of age with pure-tone thresholds greater than or equal to 25 dB HL in both ears. The results showed that background noise can have negative effects on the ability to multitask for both younger adults with normal hearing and older adults with hearing loss; however, this effect was greater for the older adults with hearing loss, especially when task demands were increased.

The pyrolysis of biomass is a thermochemical process in which woody biomass is converted to several high-value products such as bio-oil, bio-char and syngas. The forestry sector has shown particular interest in this process as a large quantity of biomass is produced as an underutilised by-product in this sector annually. Dual fluidised beds (DFBs) have been identified as a feasible reactor system for this process. However, little attention has been given to the optimisation or to the design of a scalable DFB for the pyrolysis of biomass process. Therefore, the objective of the current project was the design, modelling and construction of a scalable dual fluidised bed system for the pyrolysis of biomass. In order to achieve this objective, several tasks were performed, which included the following: <ul> <li> A literature study was done in order to obtain a theoretical foundation for the current project.</li> <li> A novel dual fluidised bed reactor system was designed, which included the block flow diagram and the process and instrumentation diagram for the system.</li> <li> A cold unit of the system was built in order to test the performance of the system.</li> <li> A comprehensive model for the system was developed, which included mass and energy balance considerations, hydrodynamics and reaction kinetics.</li> <li> A complete pilot-scale system of the proposed design was built and tested at the University of Pretoria.</li></ul> Solids are heated by means of combustion reactions in one of the fluidised beds in the proposed dual fluidised bed design. An overflow standpipe is then used to transport the solids to a second fluidised bed in order to provide the energy required for the endothermic pyrolysis reactions. The cooler solids are then fed back to the combustion fluidised bed by means of a screw-conveyor, creating a circulating system. A two-stage model was used to model the pyrolysis reactions. In this model, the wood is converted to bio-char, syngas and tar compounds. The tar compounds are the desired product as they can be condensed to form liquid bio-oil. However, these compounds undergo a second reaction in the gas phase in which they are converted to bio-char and syngas. It is therefore necessary to quench these gases rapidly in order to maximise the yield of bio-oil obtained from the system. Bio-oil is a source of many high-value chemicals and can also be upgraded to produce liquid bio-fuels. A portion of the syngas is recycled back to the pyrolysis fluidised bed in order to fluidise the bed. In this way, oxygen is prevented from entering the pyrolysis fluidised bed, which would cause the biomass in the bed to undergo combustion rather than pyrolysis. The operating temperatures of the combustion and pyrolysis fluidised beds were optimised at 900°C and 500°C respectively. A cold unit of the system was built at the Agricultural Research Service in Wyndmoor, Pennsylvania, USA. From the experiments performed on this unit it was found that the solid transport mechanism designed during the project is suitable for the pyrolysis of biomass process. In addition, the solids circulation rate between the two beds was easy to control, which is necessary in order to maximise the yield of bio-oil obtained from the system. A pilot-scale unit of the dual fluidised bed design was built in order to finalise the design and ensure that it could be scaled up. This system included all the downstream units, which had to be designed for the dual fluidised bed system. Several cold-run experiments were also performed on the pilot-scale system in order to ensure that it would perform as required during operation. It was found that the combustion fluidised bed could be fluidised as required and that the circulation of solids between the combustion and pyrolysis fluidised beds functioned well and could be easily controlled. Therefore, it was concluded that the proposed dual fluidised bed system is suitable for the pyrolysis of biomass process and is a feasible reactor system for the large-scale pyrolysis of biomass. The large-scale operation of the proposed dual fluidised bed system offers several advantages, particularly within the forestry sector. These advantages have important implications, as follows: <ul> <li> The current research offers the opportunity for the forestry sector to shift its focus from the production of traditional wood products, such as pulp and paper, to products such as specialised chemicals.</li> <li> The bio-oil produced in the dual fluidised bed system can be upgraded to renewable liquid fuels, which may help reduce the dependence of the infrastructure on fossil fuels.</li> <li> The dual fluidised bed system provides an opportunity for capturing and removing CO2 from the atmosphere in the form of bio-char. It is therefore considered to be a carbon-negative process, and may help reduce the concentration of greenhouse gases.</li> <li> The bio-char produced in the dual fluidised bed system can be used to feed nutrients back to plantation floors in the forestry sector, thereby aiding the growth of further plantations.</li></ul> Copyright / Dissertation (MEng)--University of Pretoria, 2013. / Chemical Engineering / unrestricted

Within Canada, high school sport is the most popular extracurricular activity (Statistics Canada, 2008). Previous research has found that teachers who take additional roles may increase their chances of role conflict and occupational dissatisfaction (Richards & Templin, 2012). Little research has examined the motivations teacher-coaches have for taking on a dual-role. Further, researchers assert that high school sport can facilitate positive youth development (Camiré, & Trudel, 2010). The purpose of this thesis was to gain a more in-depth understanding of this dual-role as well as perceptions related positive youth development. Results of the research are presented in two articles. The first article examines teacher-coaches motives for taking on a dual role position. The second article examines the perceptions teacher-coaches have related to the impact of participation in high school sport. Overall, the results produced rich insight into the world of volunteer teacher-coaches and student-athlete development in high school sport.

One of the most interesting aspects of Le Petit Prince by Antoine de Saint-Exupéry (1999[1946]) is its dual address. The illustrated narrative is at once a charming story for children and an allegory inviting adults to consider philosophical questions. In the graphic-novel adaptation of the book by Joann Sfar (2008), this allegory is obscured:; the abstract, philosophical ideas recede to the background while the material details of the story become more prominent. But this recession of the allegory does not mean that the adaptation turns its back on adult readers completely. The graphic novel creates a web of intertextual references, which, among other things, amplify the suggestion in the source text that the protagonist is Antoine de Saint-Exupéry himself. It thus displaces the adult interest from allegory to autobiography and the mechanism of adult address from allegory to intertextuality, restricting its adult audience. For those adult readers who remain addressed by the graphic novel, however, the text identifies itself explicitly as a translation, which has consequences for we should think about the “voice” of the translator. Un des aspects les plus intéressants du livre Le Petit Prince d’Antoine de Saint-Exupéry (1999 [1946]) tient au fait que le récit illustré est une histoire charmante pour les enfants en même temps qu’il invite les adultes à réfléchir à des questions philosophiques. Dans l’adaptation du récit en bande dessinée par Joann Sfar (2008), les éléments abstraits du livre s’estompent derrière les détails concrets de l’histoire. Cet effacement de l’allégorie ne signifie pourtant pas que la bande dessinée tourne le dos aux adultes : elle crée un réseau intertextuel qui renforce l’impression donnée par le texte source que le véritable protagoniste est Antoine de Saint-Exupéry. Ainsi, l’intérêt pour les questions philosophiques se reporte sur l’autobiographie et, passant de l’allégorie à l’intertextualité, la bande dessinée sollicite alors moins les adultes. Cependant, pour les adultes auquelles la bande dessinée s’addresse toujours, le texte s’identifie explicitement comme une traduction, ce qui implique une réévaluation du concept de la “voix” du traducteur.

There are currently millions of domestic workers as vulnerable and underclass workers in China. The demand for domestic workers will continue to increase in another millions of urban families in time of ageing and labour shortage. Domestic workers are predominantly working poor female, low-skilled migrant and informal: these three characteristics have determined their poor conditions in the cities. When such a large body of domestic workers live in the improvised, disadvantaged and discriminated conditions in urban China, it is crucial to undertake a critical analysis of this issue to explore why this has happened and why it has been so hard to change their conditions. This thesis seeks to explain: why is there a persistent lack of social and legal protection for these vulnerable workers in urban China? To do so, I first explore two lines of theoretical frameworks to construct the issues of domestic workers in 1) the gender implications of domestic work and 2) the relationship between migration and labour market mechanism. Second, I analyse the larger socioeconomic structures that shape the working and living conditions of domestic workers. The process of reconstructing the dual labour system integrated with the institutionalized urban registration system in China has exacerbated the divergence between countryside and cities, between men and women, and between formal and informal labour. Third, I use the case studies to present the consequences of the informality of domestic work service in China, including the unrecognition of labour law, the unequal power relationship between service employers and domestic workers, and the media’s biased position in promoting the in-home care model. I find that the state has designed multiple institutions to secure a pool of cheap labour from the rural regions to facilitate the urbanisation at a low price. In particular, the central government has prioritised the urban development by encouraging more women to participate in the labour force and justified its absence in the provision of public elderly care by outsourcing the care services to the private market of domestic workers.

Les aciers Dual-Phase constituent plus de 50% du poids des automobiles récentes. Ils associent une très bonne formabilité à une haute limite à rupture. Cet excellent compromis mécanique résulte de leur microstructure biphasée, constituée d’une phase martensitique dure englobée dans une matrice ferritique ductile. Ces aciers contiennent principalement du carbone et du manganèse. Les ségrégations chimiques formées lors de la coulée créent, à l’issue des traitements thermo-mécaniques ultérieurs, des structures en bandes ferrito-martensitiques néfastes aux propriétés d’endommagement. Les principaux objectifs de cette thèse étaient de comprendre les mécanismes de formation des bandes, et de relier leurs caractéristiques (intensité, topologie…) aux paramètres du procédé. Des cycles thermiques inspirés du procédé industriel ont été réalisés sur des échantillons d’une nuance représentative (Fe-0.15%C-1.5%Mn). Plusieurs techniques expérimentales (dilatométrie, microscopies, sonde électronique, EBSD…) ont été mises en oeuvre pour comprendre les mécanismes de développement des microstructures. Des outils de visualisation et de quantification de la topologie bidimensionnelle et tridimensionnelle des microstructures ont été développés, permettant d'évaluer l’influence des paramètres du traitement thermique sur la microstructure finale. Pour différentes topologies, les champs de contraintes locaux responsables de l’endommagement ont été estimés à l’aide de simulations par éléments finis. Les informations recueillies permettront d’alimenter des modélisations numériques visant à reproduire la genèse des microstructures et à prévoir leur comportement mécanique en grande déformation / Modern cars are composed in weight of more than 50% of Dual-Phase steels. They combine a very good formability and high level of strength. This excellent mechanical accommodation is due to their two-phase microstructure, composed of hard martensite phase in a ductile ferrite matrix. These steels contain principally carbon and manganese. Chemical segregations developed during the casting create, after subsequent thermo-mechanical treatment, banded structures of ferrite and martensite unfavorable for damaging properties. Main objectives of this thesis were to understand mechanism of bands formation, and link their characteristic (intensity, topology…) to the process parameters. Some heat treatment routes derived of the industrial process were realized on sample of representative grade (Fe-0.15%C-1.5%Mn). Several experimental techniques (dilatometry, microscopy, electronic probe, EBSD…) were operating to understand mechanism of microstructures development. Some tool of visualization and quantification of the two-dimensional and three-dimensional were developed, enable to evaluate the influence of heat treatment parameters on the final microstructure. For different topologies, the local stress fields liable of damaging were estimated with the support of finite elements simulations. The collected information will allow loading numerical modeling with the purpose to reproduce microstructures genesis and to predict their mechanical behavior in high strain

In general, Dual-Band technology enables microwave components to work at two different frequencies. This thesis introduces novel dual-band microwave components and their applications. Chapter 2 presents a novel compact dual-band balun (converting unbalanced signals to balanced ones). The ratio between two working frequencies is analyzed. A novel compact microstrip crossover (letting two lines to cross each other with very high isolation) and its dual-band application is the subject of chapter 3. A dual-frequency cloak based on lumped LC-circuits is introduced in chapter 4. In chapter 5, a dual-band RF device to detect dielectric constant changes of liquids in polydimethylsiloxane (PDMS) microfluidic channels has been presented. Such a device is very sensitive, and it has significantly improved the stability. Finally, conclusion of this thesis and future works are given in chapter 6.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2017-06-22T14:09:03Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Maria Rita Tese final pdf.pdf: 2723454 bytes, checksum: a5c4d5dde08d65f1641e2216cc5b4257 (MD5) / Made available in DSpace on 2017-06-22T14:09:04Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Maria Rita Tese final pdf.pdf: 2723454 bytes, checksum: a5c4d5dde08d65f1641e2216cc5b4257 (MD5) Previous issue date: 2016-05-19 / A tese reflete a interpretação adotada no Brasil, sobre o exercício da autonomia na constituição de filiação. Partindo de uma visão histórica do comportamento humano em família e a relativização dos conceitos e convenções no tempo, busca-se a justificativa para o limite binário do sistema de filiação que vem sendo criticado por crescente entendimento que o relativiza, em nome da ampliação da liberdade existencial. A socioafetividade e os avanços da biotecnologia na reprodução humana são frequentemente invocados pela doutrina e em decisões judiciais, que defendem a relativização da binariedade e a existência de novas “categorias” como a “multiparentalidade”. Tal relativização tornou-se uma tônica sem reflexões sobre o paradigma consequencialista, que é limitado em nosso sistema. A autonomia das relações privadas no Estado Liberal abstencionista pautou-se em um individualismo, que findou gerando sérios desequilíbrios na igualdade entre as partes. Já no Estado Social que intervém protetivamente, e busca garantir direitos fundamentais, a autonomia resvala de um interesse individual a um interesse coletivo e de ordem pública e submete o indivíduo a limites que visam a segurança e estabilidade nas relações existenciais. Nesse sentido, a tese conta com uma base doutrinária nacional e estrangeira, além de pesquisa jurisprudencial e sociojurídica na esfera da autonomia parental, contribuindo para uma revisão na aplicabilidade das normas de responsabilidade parental que proporcione soluções harmônicas em nosso sistema jurídico e garantia de sua unidade. / The thesis reflects the interpretation adopted in Brazil, on the exercise of autonomy in the constitution of membership. From a historical view of human behavior in the family and the relativization of the concepts and conventions in time, seeks the reason for the torque limit of the membership’system that has been criticized for growing understanding that relativize it, on behalf of the expansion of existential freedom. The partner affection and advances in biotechnology in human reproduction are often invoked by the doctrine and judicial decisions, defending the relativization of binarity and the existence of new "categories" like "multiparentality". Such relativism had become a tonic without reflections on the consequentialist paradigm, which is limited in our system. The autonomy of private relations in the Liberal State abstentionist was based on individualism, which ended causing serious imbalances in equality between the parties. In the welfare state intervening protectively, and seeks to ensure fundamental rights, autonomy slips of an individual interest to a public interest and public order and submits the individual limits that aimed at security and stability in existential relations. In this sense, the thesis has a national and foreign doctrinal basis, and jurisprudential and socio legal research in the sphere of parental autonomy, contributing to a review of the applicability of parental liability rules to provide harmonic solutions in our legal system and its unit warranty.

Introduction: The prefrontal cortex (PFC) is highly susceptible to age-related deterioration. As such, executive function deficits are commonly observed when older adults process two attention-demanding tasks simultaneously. Everyday tasks such as walking and talking on the phone involve executive functions and the integration of cognitive-motor pathways. However, less is known about this relationship as cognitive demands increase. Methods: Twenty healthy older adults (M = 71.8 years, SD = 6.4) performed four auditory cognitive tasks of increasing demand, including a simple reaction time (SRT), go/no-go (GNG), n-back (NBK), and double number sequence (DNS) task with or without self-paced walking (i.e., single- versus dual-task). Using a blocked design, prefrontal hemodynamic changes (i.e., oxy- [∆HbO2] and deoxyhemoglobin [∆HbR]) were measured using functional near-infrared spectroscopy (fNIRS) and performance was assessed using measures of response time (s), accuracy (% correct) and gait speed (m/s). Results: Prefrontal activation decreased between the single- and dual-tasks across all task demands. Behaviourally, the SRT response times were significantly faster than GNG and NBK. Accuracy decreased between single- and dual-tasks and with increasing demand, but the NBK and DNS tasks were not significantly different. An interaction between task and demand was observed for gait speed such that the DNS dual-task was significantly slower than the single-task. Conclusion: Neural findings support an automatic locomotor control strategy in that cerebral oxygenation decreased between single- and dual-tasks and gait speed was maintained up until the most demanding cognitive task. However, decreased prefrontal activation was inefficient at supporting response time and accuracy performance which may indicate that cognitive performance is differentially affected by cognitive demand and deficits in executive functioning.

BACKGROUND: Age-related deterioration in the nervous system results in the decline of motor and cognitive abilities, which both have been identified as contributing to fall risk in older adults. Dual-task gait, which involves walking while performing a secondary cognitive task, is a common way to assess the interactions between cognitive and motor function. Previous work has established associations between the cost of the cognitive load on gait parameters (e.g., velocity) and fall risk in older adults. However, to date, no study has explored the potential value of combining a direct measure of performance on the cognitive component of the dual-task with the gait measures in fall risk prediction modeling. RESEARCH QUESTIONS: Does including measures of performance on the cognitive task in dual-task walking with the gait velocity measures enhance the capacity to predict fall risk. Is this predictive capacity different in models employing dual-task gait velocity versus models including the cost of the cognitive load on gait velocity? METHODS: Thirty-two community-dwelling older adults (76 years ± 3.44) were classified as fallers (n = 17) and non-fallers (n = 15) based on self-report of having at least one fall in the past 12 months. They completed single-task and dual-task walking on a pressure-sensing electronic walkway system. A progressively enhanced series of logistic regression models were performed commencing with gait velocity during the dual-task (Loaded Gait Velocity, LGV) as the covariate in predicting fall risk. This model was subsequently augmented by adding a measure of cognitive performance covariate and then further augmented with the addition of the interaction variable between the LGV and the cognitive performance variables. This stepped series of modelling was then repeated with the dual-task cost gait velocity (DTCGV, difference in gait velocity between single and dual-task). RESULTS: With the addition of the cognitive measures (CM) and the interaction variables between the GV and CM variables, in both the LGV and DTC_GV models, the Nagelkerke’s R square increased as did the models’ respective sensitivity. Notably, the model including the LGV, CM and the interaction variables achieved 88.2% sensitivity, 80% specificity, with an overall classification accuracy of 84.4%. DISCUSSION: This study is the first to show that the ability to identify fallers and non-fallers is enhanced by using both gait and cognition measures as well as interaction variables between gait and cognition measures. Further, our findings suggest that the added value of the cognitive measures is best realized with LGV rather than DTCGV. It reasons that because DTC already encompasses the cost of the cognitive load on the motor performance (gait velocity), combining it with cognitive metrics does not enhance its predictive capacity. This work suggests there is clinical utility of including cognitive performance measures in fall risk modeling as well as it provides further evidence of the interplay between cognitive and motor function in fall risk. / Graduate