Le développement d'outils prédictifs est nécessaire pour la conception des nouvelles générations de transmission à variation continue (CVT) à courroie de caoutchouc. Ce mémoire présente un modèle de CVT à courroie de caoutchouc, capable de prédire la réponse temporelle du rapport de transmission pour des variations de la force de serrage de la poulie motrice, du couple et du régime moteur. Pour ce faire, la courroie est discrétisée en noeuds sur lesquels s'exercent les forces internes de la courroie ainsi que les forces de contact imposées par les poulies. Les relations permettant de déterminer ces dernières sont développées, considérant la physique du contact entre les poulies et la courroie. La réponse temporelle du rapport de transmission est obtenue par la solution des équations différentielles découlant de l'application des lois de la mécanique classique sur les noeuds. Les résultats du modèle concordent avec les mesures expérimentales prises dans des conditions d'opération représentatives de l'exploitation normale des CVT. La similarité des prédictions du modèle et des résultats de tests est présentée à la fois pour le régime transitoire et les conditions stabilisées, validant que l'approche utilisée est valable et qu'elle permet l'obtention de résultats inatteignables jusqu'à présent. L'utilisation du modèle présenté dans ce mémoire aidera les concepteurs des futures générations de CVT en leur permettant d'anticiper le comportement de la transmission, sans avoir recours au prototypage.

Until very recently language development research classified the language learner as belonging to one of two discrete groups – monolingual or bilingual. This thesis explores the hypothesis that this is an insufficient description of language input and that there are sub-groups within the monolingual category based on the phonological variability of their exposure that could be considered akin to that of bilingual toddlers. For some monolingual toddlers, classified as monodialectal, their language exposure is generally consistent, because both of their parents speak the dialect of the local area. Yet for other toddlers, classified as multidialectal, the language environment is more variable, because at least one of their parents speaks with a dialect that differs from the local area. It is considered that by testing this group of multidialectal toddlers it will be possible to explore the effect of variability on language development and how increased variability in the bilingual linguistic environment might be influencing aspects of language development. This thesis approaches the influence of variability from three areas of interest: phonetic specificity of familiar words using a mispronunciation paradigm (Experiments 1 and 2), target recognition of naturally occurring pronunciation alternatives (Experiments 3 and 4) and use of the Mutual Exclusivity strategy in novel word learning (Experiment 5). Results show that there are differences between the two dialect groups (monodialectal and multidialectal) in a mispronunciation detection task but that toddlers perform similarly with naturally occurring pronunciation alternatives and in their application of the Mutual Exclusivity strategy. This programme of work highlights that there is an influence of linguistic variability on aspects of language development, justifying the parallel between bilingualism and multidialectalism.

Studien är utförd på ett fallföretag med syftet att skapa en djupare förståelse för hur stabilisering av en produktionsprocess påverkar kapacitetsutnyttjandet. Nuläget analyserades genom observationer, intervjuer och företagets egen dokumentation. Två experiment utfördes vilket resulterade i att ett samband hittades mellan variationer och kapacitetsutnyttjandet i en produktionsprocess. Vidare avgränsades vilka produktionsförutsättningar som gav högst kapacitetsutnyttjande. Slutligen presenteras hur det ökade kapacitetsutnyttjandet påverkar de ekonomiska resultaten samt studiens slutsats och rekommendationer till fallföretaget.

Detta arbete syftar till att undersöka lärares syn på att variera undervisningsmetoderna i matematik. I kapitlet tidigare bakgrund presenteras flera olika forskningsbeprövade metoder som kan användas för att variera undervisningen. Det är dessa metoder som är grunden för analysen av den data som samlas in i studien. Semistrukturerade intervjuer valdes som metod för att samla in data till denna studie. Det är sex lärare som har intervjuats och dessa är alla verksamma inom årskurs 4-6 och undervisar i ämnet matematik. Respondenterna valdes ut genom att skolledningen på flera skolor kontaktades med en förfrågan om att vi ville komma i kontakt med lärare som undervisade i matematik och sedan fick de lärare som var intresserade höra av sig till oss för att vara med i studien. I metodkapitlet redogörs det även för hur arbetet lever upp till de etiska krav som finns och hur detta arbete lever upp till kraven på trovärdighet, tillförlitlighet och överförbarhet. Resultatet och analysen visar att alla lärare använder sig av flera olika metoder i sin undervisning och att alla anser att det är viktigt att variera undervisningsmetoderna då detta leder till att eleverna ser matematiken ur olika perspektiv och lär sig behandla det matematiska innehållet på flera sätt. Enligt lärarna tycker eleverna även att matematiken blir mer lustfylld om undervisningsmetoderna varieras. De nackdelar som lärarna lyfter är främst att elever som har det svårt med matematiken kan tycka att det är jobbigt att undervisningen varieras och att det kan ta mycket tid att variera undervisningen så att allt som ska göras inte hinns med. Av de sex lärare vi har pratat med så menar majoriteten att när de varierar undervisningsmetoderna så är det främst elevernas motivation som stärks. Det är enbart en av lärarna som säger att förmågorna kan tränas genom att variera metoderna och att detta då gör att eleverna lär sig mer.

published_or_final_version / abstract / Microbiology / Doctoral / Doctor of Philosophy

ABSTRACT This Thesis investigates ionospheric plasma flows (commonly referred to as “convection”) at high latitudes with the objectives to assess seasonal and solar cycle variations in the shape of the flow patterns and the flow intensity in terms of external drivers of the flow, first of all the magnitude and orientation of the interplanetary magnetic field (IMF). Multi-year (2001-1011) line-of-sight Doppler velocity data collected by the Super Dual Auroral Network (SuperDARN) HF radars are considered. Two approaches are used: 1) analysis of monthly-averaged 2-dimentional patterns inferred from data of all SuperDARN radars operated and 2) analysis of near magnetic noon data from only two SuperDARN radars, Rankin Inlet and Inuvik monitoring meridional component of the flow in the near North Pole areas (polar cap). We show and discuss seasonal and solar cycle variations of three characteristics of the flows: magnetic latitudes of the region where plasma flow direction changes from toward the noon to away from the noon (convection reversal boundary), the magnetic local time location of the near noon region with stagnated flow (throat region) and, finally, the magnitude of the flow. All three parameters show trends, although not strong and consistent all the time, which agrees with previous publications where different analysis approaches and more limited data sets were used. For two specific points, one at the magnetic latitude of 72 degrees, representing the auroral oval latitudes (region where optical arcs occur most frequently) and the other one at 82 degrees, representing the polar cap latitudes we demonstrate that the average flow magnitude increases with the IMF intensity, and the effect is much stronger for the negative vertical component of the IMF Bz. In our second approach we demonstrate that the flow velocity increases almost linearly with an increase of the reconnection electric fields characterizing processes of interaction between the solar wind/IMF and the Earth`s magnetic dipole. Saturation effect is seen for strongest electric field. More clear seasonal effects are noticeable in these data; the velocity response to the reconnection electric field enhancement is stronger summer (winter) time for positive (negative) IMF Bz. The data are consistent with previous reports, where highly smoothed velocity data were considered.

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The current research program was designed to evaluate the impact of various dietary and ingredient nutrient profiles and exogenous enzyme inclusion on growth performance and energy utilization in broilers. Experiment one was designed to observe increasing levels of distillers’ dried grains with Solubles (DDGS) and a non-starch polysaccharide degrading enzyme (NSPase) on energy digestibility. Experiment two evaluated the influence nutrient variation in corn and xylanase supplementation on growth performance and nutrient utilization. In experiment one, DDGS concentration was increased from 0 to 15% in 5% increments and included the addition of an NSPase enzyme. Early broiler body weight and FCR was negatively affected with increasing DDGS concentration up to 15%. The decreased growth performance was associated with a decrease in energy and nitrogen utilization as a linear decrease was observed in IDE, INDC, and AMEn. Addition of the NSPase negated many of the negative effects on nutrient utilization as improvements in all digestibility measurements were observed. Interactions were observed with DDGS concentration and NSPase inclusion as the benefit of enzyme inclusion was augmented as DDGS level increase. Experiment two evaluated different corn crops from six geographical locations in the US in an effort to determine the effects of xylanase inclusion and corn nutrient variation on growth performance and nutrient utilization. Significant differences were observed in growth performance, IDE, and AMEn in broilers when fed corn. Corn source impacted early body weights, and FCR throughout the experiment. Energy utilization was also impacted on all measured parameters, following the starter phase (day 17) and at the conclusion of the trial (day 41) by corn source. Xylanase inclusion improved FCR during the finisher phase as well as the cumulative FCR (day 1-41). Digestibility data indicates that corn source impacts the xylanase effectiveness in young broilers, as improvements were not observed in all corn types. Xylanase inclusion, however, did increase IDE and AMEn in all corn sources on day 41 of age. Data from this research program confirm that ingredient nutrient content, through the presence of ingredients with anti-nutritive properties or the incidence of varying nutrient profiles, does impact observed growth performance as related to reduced nutrient digestibility. Additionally, the inclusion of a dietary exogenous enzyme does improve energy and nitrogen digestibility in broilers, ultimately improving growth performance of broilers and improving efficiency.