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Douze ans constituent un délai raisonnable pour faire un bilan global de la procédure de l'article L. 521-1 du Code de justice administrative. L'examen des évolutions jurisprudentielles et l'analyse des dernières dispositions législatives font percevoir l'élargissement du domaine d'application du mécanisme qui est, dans l'ensemble, cohérent. Doté de nouvelles prérogatives subtiles et redoutables, le juge du référé-suspension assume parfaitement son rôle du juge de l'équilibre et de la nécessité. Il est le garant de la protection provisoire. L'efficacité est le noyau dur de sa fonction. Le changement d'état d'esprit et d'attitude du juge administratif a eu des conséquences à la fois théoriques et pratiques en la matière. De part sa gestion rapide, son accessibilité, son mode de raisonnement et sa créativité, le juge du référé-suspension est juge de la rupture. À cela, s'ajoutent la préoccupation du juge des effets de ses interventions et la flexibilité des mesures prononcées. Disposant ainsi d'une véritable culture de l'urgence, le juge a gagné de la crédibilité et de la légitimité et est, surtout, devenu un concurrent redoutable face à ses homologues, que ce soit au niveau national ou européen. Bien que performant, le juge des référés n'est pas au bout de ses potentialités. La continuité entre le référé- suspension et son ancêtre est tangible. Le système reste imparfait. Nombreux en sont les points perfectibles. Pour y remédier, le juge ainsi que le législateur doivent rester en mouvement. / Twelve years represent reasonable time to make a global report on the procedure of article L.521-1 of Code of adminstrative law. The examination of case law evolution and the analysis of last legal measures allow us to detect an enlargment of field which is consistent. Equipped with new subtly and dreaded prerogatives, summary's judge of suspension of administrative act, assumes perfectly his duty of judging balance and necessity. He is the guarantor of the temporary protection. Efficacity constitutes his function'hard core. The change of state of mind and attitude of administrative judge had consequences both theorical and practical in the subject. Due to his fast management, his accessibility, his way of reasoning and its creativity, the summary's judge of suspension is the judge of breach. Beyond that, are added the judge's preoccupation of teh effects of his intervention and the flexibility of delivered sentences. The judge has won credibility and legitimacy by having a real cukture of emrgency and became a tremendous rival opposite to his homolog on nation-wide or European-wide. Although efficient, summary's judge has more potentialities. The continuity from summary-suspension and his ancestor is real. The system is still imperfect. To solve this, the judge and lawmaker have to stay in alert.

En raison de leur utilisation répandue dans les soins de santé humaine et animale, les antibiotiques et autres résidus de médicaments sont omniprésents dans l’environnement en général et le milieu aquatique particulièrement. Compte tenu de leurs impacts potentiels sur le fonctionnement de l'écosystème et la santé publique, la quantification des résidus de médicaments sur l'environnement est devenue une nécessité. Diverses techniques d'analyse se sont avérées être appropriées pour la détection fiable de tels composés. Cependant, la quantification peut être difficile car ces contaminants émergents sont présents à l’état de traces ou d'ultra-traces. Par conséquent, l'exactitude des analyses environnementales dépend à la fois de l'efficacité et de la robustesse de la méthode d'extraction et de quantification. Des procédures d’analyse de traces de ces contaminants émergents, ont été donc mise au point et des méthodes basées sur des analyses LC-MS/MS ont été développées. Pour les échantillons aqueux, l’extraction est menée sur phase solide (SPE, OASIS HLB). Les MLOQ sont comprises entre 0.2 et 3 ng/L. Pour la matrice solide, la procédure d’extraction à haute température et pression a été utilisée suivie d’une purification SPE. Afin d’évaluer le contexte de la pollution totale, la méthodologique analytique validée a été appliquée à des échantillons d’eaux potables et usées provenant de la France et de la Tunisie. Les résidus de médicament associés à la matière solide en suspension (MES) ont également été quantifiés pour compléter l’évaluation du degré de pollution environnementale. / Due to their widespread use in human and animal health care, antibiotics and other drug residues are ubiquitous in the environment in general and the aquatic environment in particular. Given their potential impacts on the functioning of the ecosystem and public health, the quantification of drug residues on the environment has become a necessity. Various assay techniques have been found to be suitable for the reliable detection of such compounds. However, quantification can be difficult because these emerging contaminants are present in the trace or ultra-trace state. Therefore, the accuracy of environmental analyzes depends on both the effectiveness and the robustness of the extraction and quantification method. Trace analysis procedures for these emerging contaminants were therefore developed and methods based on LC-MS / MS analyzes were also developed. For aqueous samples, extraction is carried out on solid phase (SPE, OASIS HLB). MLOQs range from 0.2 to 3 ng / L. For the solid matrix, the extraction procedure at high temperature and pressure was used followed by SPE purification. To assess the context of total pollution, the validated analytical methodology was applied to drinking and wastewater samples from France and Tunisia. Drug residues associated with suspended solid matter (SSM) were also quantified to complete the assessment of the degree of environmental pollution.

Employers often wrestle with whether or not to suspend an employee and the issue is what needs to be done before an employee could be suspended. Suspending an employee means to deprive him or her from entering the work place for a period of time, due to alleged misconduct which, due to the nature of the alleged misconduct and in the opinion of the employer, warrants the employee not to be in or near the workplace. Section 23 of the Constitution of the Republic of South Africa, affords every employee the right to fair labour practices and this right should be affected by the Labour Relations Act, 1995 (LRA). Unfortunately the LRA only deals with the unfair suspension under the definition of an unfair labour practice in section 186(2) by stating that the meaning of unfair labour practice is any act or omission that arises between an employer and an employee involving the unfair suspension of an employee or any other unfair disciplinary action short of dismissal in respect of an employee. The focus of this document thus is to scrutinise the lack of legislative guidelines relating to the procedural fairness of suspension of employees. It would thus necessitate an overview of the nature of suspension which would be discussed in length by way of referring to the right to suspend an employee as well as the application of the courts in such cases, the distinction between suspension as a preventative, or as a punitive measure and the possibility of suspension resulting in an unfair labour practice. The distinction between preventative and punitive suspensions are highlighted. Since it is not clear when, how and for how long an employee may be suspended, in the absence of clear guidelines, employers have to turn to the courts’ interpretation to get the necessary guidance on the application of a suspension. In order to ensure that the employer, experiencing unnecessary difficulty with the implementation of procedural fairness of suspensions, in a meaningful way, be assisted by the proposal that legislature consider to address this by including clear guidelines under Item 3 of Schedule 8 of the LRA.

This thesis concerns design of two pieces of suspension dewatering equipment (i.e. transient batch settlers and steady state continuous gravity thickeners). In a transient batch settler, very slow densification of aggregates within the suspension is considered whilst the drag on the solids in the suspension is assumed to be negligible. The interface of the suspension is then determined by a balance between gravity and the gradient of the compressive yield stress of the gelled suspension. The compressive yield stress functional form in general could be either a weakly gelled formula, or a strongly gelled formula. These formulae differ in the way they behave for solids concentrations in the neighbourhood of the suspension gel point. The effects of the above two gel formulae, the evolution of the compressive yield stress functional form over time during aggregate densification, different initial suspension heights, and different initial feed solids volume fractions upon the predictions of consolidated bed structures and solids volume fractions obtained at the bottom of a batch settler, and upon the evolution of the heights of the suspension and the consolidated bed have been explored. A sufficiently tall initial suspension height might lead to insignificant increases in the solids volume fractions obtained at the bottom of batch settlers after time-dependent aggregate densification. The interfaces of the suspension and the consolidation zone coincide after aggregate densification if the gel point, which increases with time, is larger than the initial feed solids volume fractions. Moreover, the maximum permitted underflow solids fluxes predicted from steady state thickeners have been investigated and compared. Pre-shearing of aggregates which densifies aggregates to have smaller diameters upon entering the thickener is necessary if large underflow solids fluxes and small underflow solids volume fractions are specified. The solids volume fraction at the top of the consolidated bed which is the densified gel point is influenced by the extent of pre-shearing of aggregates. An algorithm for determining this densified gel point has also been developed. In reality, thickeners contain not just a consolidating bed, but also a hindered settling region above it. When the hindered settling region is considered in a thickener, the effects of the extent of aggregate densification that has occurred in the hindered settling region and how that impacts upon thickener performance and sludge rheological properties have been explored in this thesis. A new algorithm for predicting the densified gel point obtained at the top of the consolidated bed has been developed when the hindered settling region is present. The effects of underflow solids volume fractions, aggregate densification rate parameters and pre-shearing of aggregates upon the predictions of maximum permitted underflow solids fluxes, sludge rheological properties, and thickener performance have been explored. The predictions of thickener performance using both the weakly and strongly gelled formulae have also been achieved. In cases where it is possible to neglect the hindered settling region, substantial increases in the maximum permitted underflow solids fluxes, and substantial decreases in the consolidated bed heights and the total solids residence times have been achieved after aggregate densification for a comparatively small underflow solids volume fraction. The benefits arising from aggregate densification are more modest if the underflow solids volume fraction is larger. On the other hand, when the hindered settling region is included, more densification of aggregates occurring in the hindered settling region might lead to taller consolidated bed heights for a specified suspension flux and a specified aggregate densification rate parameter due to higher underflow solids volume fractions.

Magnetic bearings have recently begun to be employed in rotating machinery for vibration reduction, elimination of oil lubrication problems and prevention of failures. This thesis presents an analysis and design of an experimental model of a magnetic suspension system. The magnetic bearing, its control circuit and the supported object are modeled. Formulas are developed for the position and current stiffness of the bearing and the analogy with a mechanical system is shown. The transfer function is obtained for the control and experimental results are presented for the double pole one axis magnetic support system. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

To create a legible building, the structure's form must describe and reinforce the mission of the organization that inhabits it. This proposal for a regional competition, training and recreational aquatics facility demonstrates ideas of physical fitness through an exploration of muscles, cables, tension, joints, and bones. The building is part of a larger urban strategy for redeveloping the Washington Channel waterfront in Southwest Washington, D.C. Early images of transformed beach glass, thread, and basswood generated the inspiration for the basic architectural components: the wall, the columns, and the suspended jewels. The following document gives definition to the basic elements. / Master of Architecture

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Dans ce travail, nous choisissons, dans l'optique de mieux comprendre le rôle joué par les éthers de cellulose dans les mortiers monocouches, d'utiliser la rhéomètrie pour identifier les mécanismes d'action de ces molécules au sein d'une pâte de ciment. Nous développons ainsi les protocoles et l'analyse associée nous permettant, à partir de mesures macroscopiques, d'affiner notre compréhension de ces molécules à une échelle microscopique. Puis, nous extrapolons de nos résultats les conséquences d'une modification du dosage ou des paramètres moléculaires de l'éther dans le cas du mortier monocouche et de sa mise en œuvre. Dans une première partie, nous étudions l'influence de l'ajout d'éthers sur la viscosité du fluide interstitiel d'une suspension cimentaire et le rôle de ce paramètre sur la rétention d'eau. Dans une deuxième partie, nous étudions l'effet des éthers de cellulose sur le seuil d'écoulement et la déformation critique de pâtes de ciment et le rôle de ces paramètres sur la capacité d'adhésion du mortier. Dans une troisième partie, nous étudions l'effet des éthers de cellulose sur la viscosité d'une pâte de ciment et le rôle de ce paramètre sur la facilité de lissage / We choose in this work to use rheology to understand the role of cellulose ethers in render mortars and identify their mechanisms of action in a cement paste. We develop some protocols and their analysis to improve, from macroscopic measurements, our understanding of these molecules at a microscopic scale. We then extrapolate from our results the consequences of a change in amount, nature or chemical structure of the ether on the render mortar fresh properties. In a first part, we study the influence of ethers on the viscosity of a cement paste interstitial fluid and the effect of this viscosity on water retention. In a second part, we study the effect of cellulose ethers on the yield stress and critical deformation of cement pastes and the role of these rheological parameters on the properties of the render mortar. In a third part, we focus on the influence of cellulose ethers on the viscosity of cement pastes and the role of this parameter on the application easiness of the render mortar

L’objectif de ce travail est de réaliser des suspensions aqueuses d’alumine, écoresponsables, dont le comportement rhéologique est adapté à la mise en forme par coulage en bande. En effet, les suspensions utilisées dans le procédé de coulage en bande sont classiquement composées d’une poudre céramique, d’un solvant, d’un dispersant, d’un liant et d’un plastifiant. Ces additifs sont généralement des polymères issus de la pétrochimie susceptibles de présenter des risques pour la santé de l’opérateur et/ou pour l’environnement (en particulier avec les solvants organiques). Ces travaux visent donc de substituer tous les additifs venant de la pétrochimie par des additifs écoresponsables, ne présentant aucun risque pour la santé de l’opérateur et pour l’environnement. Les travaux menés dans le cadre de cette thèse ont alors permis d’identifier des polymères naturels extraits de plantes comme des candidats prometteurs pour le remplacement des additifs organiques classiques. Puis, l’étude des interactions entre ces bio-polymères et l’alumine a mené au développement d’un protocole spécifique adapté à la formulation de suspensions d’alumine à base de ces bio-molécules. Ainsi, à l’aide de ce protocole, des suspensions aqueuses ont été réalisées avec ces additifs écoresponsables qui ont abouti à la réalisation de bandes crues facilement manipulables et ne présentant ni craquelures, ni bulles. Enfin, les densités après frittage obtenues sont proches des valeurs rencontrées dans la littérature / The aim of this work is focused on the elaboration of new alumina suspensions with biopolymer additives and rheological properties adapted to the tape casting process. The suspensions used in the tape casting process are basically composed of a ceramic powder, a solvent, a dispersant, a binder and a plasticizer. These additives are usually polymers coming from the petrochemical sector which show risks for the operator health or the environment (in particular with organic solvents). Thus, natural polymers extracted from plants were identified as promising candidates in order to substitute the classical organic additives. Then, the study of the interactions between different organic additives with alumina led to a specific protocol for the formulation of aqueous alumina suspensions with these bio-polymers. Then, mechanical properties of the green and sintered tapes were evaluated in relation with the nature of bio-polymer additives. The obtained densities are close to the values reported in the litterature