We give a projective resolution of a finite dimensional 𝛫-algebra 𝛬 over its enveloping algebra 𝛬<SUP>𝑒</SUP> = 𝛬<SUP>𝑜𝑝</SUP> ⨂<SUB>𝛫</SUB>𝛬. The description of this resolution is related to decompositions of the first syzygy module of 𝛬 as an 𝛬<SUP>𝑒</SUP> module. Resolutions of right 𝛬 modules 𝑀<SUB>𝛬</SUB> may be obtained by tensoring 𝑀 over 𝛬 with this bimodule resoution. We describe how to obtain such a resolution when 𝑀 is simple or when 𝑀 is given in the form of a projective presentation. Computations of <I>𝐸𝑥𝑡</I><SUB>𝛬</SUB><SUP>𝑛</SUP>(𝑆<SUB>𝑣</SUB>,𝑆<SUB>𝑤</SUB>) for certain classes of algebras 𝛬 are made using these resolutions, and applied to obtain results on global dimension. / Ph. D.

This research investigates alternate methods of implementing a redundant communications ring for polled network applications. FDDI and a unique solution (the tone method) designed specifically for this application are compared. In polled networks one of the most critical parameters is the time required to interrogate all of the nodes in the network. This parameter, called the poll time, is compared for the two solutions under various operating conditions, including the instances when the ring is intact and when the ring has experienced a failure, causing it to operate in the redundant mode. As expected, the solution designed specifically for this application performed better than FDDI. The tone method, which requires very little overhead and is not limited by distance or number of nodes, is described in detail, as are the results of poll time comparisons. / Master of Science

A study of the oxidation reactions of annotinine lactamdiol provided chemical evidence that ring A of annotinine was sixmembered and confirmed that the ether ring in annotinine was an epoxide ring. The detailed structure of ring B of annotinine was elucidated through a study of the reactions of diphenyldesoxodihydroannotinine. Unsuccessful attempts were made to correlate the structure of annotinine with the structures of lycopodine and other Lycopodium alkaloids. / Dissertation / Doctor of Philosophy (PhD)

Tires play an extremely important role in the operation of a vehicle as they transmit forces between the ground and the vehicle. Consistent efforts have been made over the years towards modeling and simulation of tires and more recently, there has been an increasing need to understand the transient response of tires to various high-frequency events such as anti-lock braking and short-wavelength disturbances from the road. Major thrust has been provided by the tire industry to develop simulation models that accurately predict the dynamic response of tires without the use of computationally intensive tools such as FEA. The objective of this research is to explain the development, implementation and validation of a simulation tool based on a dynamic tire model that would assist in the analysis of the effect of tire belt vibrations on the braking performance of a vehicle. A rigid ring tire model, tandem elliptical cam enveloping model and a rule-based ABS model have been developed for this purpose. These were combined together in a quarter vehicle model and implemented in Matlab-Simulink. These models were developed for adaptation with CarSim to provide a simulation tool that can be utilized in both tire and vehicle design processes. In addition to model implementation, a parameterization procedure was developed to estimate the parameters of the rigid ring tire and enveloping model based on experimental data for a given tire. Validation studies have also been performed to ensure the accuracy and validity of the tire model. Following this, the braking performance of ABS under different road surfaces were evaluated. Based on the simulation results, final conclusions were drawn with regards to the analysis and detailed recommendations for future work directed towards the improvement of the tool were provided. / Master of Science

Yes / A laser induced fluorescence system has been developed to visualise the oil film thickness between the piston ring and cylinder wall of a fired gasoline engine via a small optical window mounted in the cylinder wall. A fluorescent dye was added to the lubricant in the sump to allow the lubricant to fluoresce when absorbing laser radiation. The concentration of the dye did not disturb the lubricant chemistry or its performance. Degraded engine oil samples were used to investigate the influence of lubricant quality on ring pack lubricant film thickness measurements. The results show significant differences in the lubricant film thickness profiles for the ring pack when the lubricant degrades which will affect ring pack friction and ultimately fuel economy.

Making use of linear and homological algebra techniques we study the linearization map between the generalized Burnside and rational representation rings of a group G. For groups G and H, the generalized Burnside ring is the Grothendieck construction of the semiring of G × H-sets with a free H-action. The generalized representation ring is the Grothendieck construction of the semiring of rational G×H-modules that are free as rational H-modules. The canonical map between these two rings mapping the isomorphism class of a G-set X to the class of its permutation module is known as the linearization map. For p a prime number and H the unique group of order p, we describe the generators of the kernel of this map in the cases where G is an elementary abelian p-group or a cyclic p-group. In addition we introduce the methods needed to study the Bredon homology theory of a G-CW-complex with coefficients coming from the classical Burnside ring.

Les histones acetyl transférase sont une classe de protéines jouant un rôle primordial dans la modification de l'état de la structure chromatinienne. Leur capacité à réaliser des modifications post-traductionnelles des queues N-terminales d'histone contribue à l'élaboration du « code histone ». Son interprétation permet d'influer sur le recrutement de co-facteurs, l'activité des complexes de remodelage et la possibilité pour certaines d'être maintenues à travers les divisions cellulaires, mettant en évidence un mécanisme primordial dans le contrôle de l'expression des gènes. Le gène chm code pour l'une de ces protéines de la famille MYST. Découvert dans le laboratoire, son étude a révélé sa capacité à maintenir la transcription de gènes Hox, à moduler l'activité transcriptionnelle de Fos/Jun par l'acétylation de l'histone H4 aux loci des gènes cibles dans la voie de signalisation Jun N-terminal Kinase (JNK) et enfin de contrôler l'origine de réplication. Aux phénotypes majeurs des mutants zygotiques pour chm ; qui sont : un défaut de fermeture du thorax adulte et la mort au stade pupe pharate ; s'ajoute : l'apparition de soies sensorielles extra-numéraire en position dorsocentral et scutellaire, des phénotypes reliés à un défaut des voies hormonales (hormone juvénile, peptide insulinique) : anomalies lors de la métamorphose, accroissement de la susceptibilité aux stress durant le stade adulte. Mes travaux de thèse m'ont permis d'identifier la place de Chm dans la voie de régulation de la formation de cluster prérequis à l'apparition de soies sensorielles. / The histone acetyltransferase (HAT) Chameau (Chm) plays in various epigenetic mechanisms of transcription control : maintenance of Hox gene transcription ; modulation of Fos/Jun transcriptional activity by histone H4 acetylation at target gene loci; control of replication origins. Here, I will discuss about a neural function of Chm, which acts in few brain neurosecretory neurons to control the activity of neurohaemal organs. Genetic evidences for a neuroendocrine function of Chm are the following. On the one hand, chm inactivation causes phenotypes suggesting hormonal signaling defects : null mutation prevents abdominal differentiation and hatching – correlated to an juvenile hormone (JH) excess - chm late inactivation allows the emergence of adults that are highly susceptible to different types of stress (starvation, oxidative, infections) – related to a defect in insulin signaling. On the other hand, these two phenotype classes are rescued by providing back Chm in 6 neurons of the pars lateralis (CA-LPs, which innervate the CA) during development, and in 12 neurons of pars intercerabralis (IPCs, which produce insulin-like peptides and innervate the CC/CA complex) in adult. DNA chip experiments showed that chm mutation affects 6 functional classes of genes (defined by ‘biological process' Gene Ontology term) : (i) neurotransmission, synaptic activity; ii) hormones, JH and ecdysone; iii) nutritional control; iv) oxidative stress; v) life span; vi) immune defense. These classes match perfectly the phenotypes described above. Furthermore a significant fraction of these genes are similarly affected by the mutation of chm and by the inactivation of CA-LPs and IPCs neurons.

FLEXOMAT

Sejam $D$ um anel com divisão, $K$ um subanel com divisão de $D$ e $X$ um conjunto. O $D$-anel livre sobre $K$ em $X$, $D_K\\langle X angle=D\\underset{\\ast} K \\langle X angle$, possui um corpo universal de frações denominado corpo livre e denotado por $D_K\\X$. Neste trabalho fazemos uma investigação acerca de condições que, quando satisfeitas por um anel com divisão, sejam suficientes para garantir a existência de um subanel isomorfo a algum corpo livre não-comutativo, e também descrevemos famílias de anéis com divisão que satisfazem as condições encontradas. Os anéis com divisão que provamos conter um corpo livre são, em sua maioria, completamentos de corpos de frações de domínios noetherianos com topologia definida por uma valorização. / Let $D$ be a division ring, $K$ a subfield of $D$ and $X$ a set. The $D$-free ring over $K$ on $X$, $D_K\\langle X angle=D\\underset{\\ast} K\\langle X angle$, has an universal field of fractions called a free field and denoted by $D_K\\X$. In this work we look into conditions which, when satisfied by a division ring, are sufficient to guarantee the existence of a subring isomorphic to some non-commutative free field, and we also describe families of division rings which satisfy the conditions that were found. The majority of the division rings that we proved to contain a free field are completions of fields of fractions of Noetherian domains with topology defined by a valuation.

Sejam $D$ um anel com divisão, $K$ um subanel com divisão de $D$ e $X$ um conjunto. O $D$-anel livre sobre $K$ em $X$, $D_K\\langle X angle=D\\underset{\\ast} K \\langle X angle$, possui um corpo universal de frações denominado corpo livre e denotado por $D_K\\X$. Neste trabalho fazemos uma investigação acerca de condições que, quando satisfeitas por um anel com divisão, sejam suficientes para garantir a existência de um subanel isomorfo a algum corpo livre não-comutativo, e também descrevemos famílias de anéis com divisão que satisfazem as condições encontradas. Os anéis com divisão que provamos conter um corpo livre são, em sua maioria, completamentos de corpos de frações de domínios noetherianos com topologia definida por uma valorização. / Let $D$ be a division ring, $K$ a subfield of $D$ and $X$ a set. The $D$-free ring over $K$ on $X$, $D_K\\langle X angle=D\\underset{\\ast} K\\langle X angle$, has an universal field of fractions called a free field and denoted by $D_K\\X$. In this work we look into conditions which, when satisfied by a division ring, are sufficient to guarantee the existence of a subring isomorphic to some non-commutative free field, and we also describe families of division rings which satisfy the conditions that were found. The majority of the division rings that we proved to contain a free field are completions of fields of fractions of Noetherian domains with topology defined by a valuation.