Reproduction de : Thèse de doctorat : Chimie, Chimie-physique : Metz : 2002. / Titre provenant de l'écran-titre. Notes bibliographiques.

Reproduction de : Thèse doctorat : Physique : Optique : Metz : 2004. / Titre provenant de l'écran-titre. Notes bibliographiques.

Thèse de doctorat : Sciences et Technologies Industrielles : Nancy 1 : 2007. / Titre provenant de l'écran-titre. Bibliogr. Index.

published_or_final_version / Mechanical Engineering / Master / Master of Philosophy

Darbe pateiktas sluoksniuotų erdvių normalizacijos modelis, tiriama normalizuotų erdvių geometrija, randami gaunamos geometrijos vidinių siečių konstravimo metodai. Šiuo tikslu nagrinėjamos neholonominės sietys Lie sluoksniuotėse, išskiriamas vertikalų Lie sluoksniuočių ir vertikalių siečių atvejis. Nustatomi ryšiai tarp neholonominių siečių. Normalizuotų erdvių vidinių neholonominių siečių teorija yra pradedama struktūrinių modulių ir konstravimu, leidžiančiu vidines , ir - sietis apibrėžti reikalavimais , ir . Sietys, gaunamos normalizuojančioje Lie sluoksniuotoje vadinamos normalinėmis sietimis. Normalinės sietys, suderintos su vidinėmis sietimis, yra vidinėmis normalinėmis sietimis. / This paper deals with the normalization model of the fiber spaces . The geometry of normalized space is researched. The methods of derivable geometric intrinsic transfer construction are discovered. For this purpose non-holonomy transfers in Lie fibers are analyzed, the case of vertical Lie fibres and vertical transfer is distinguished. The links among non-holonomy transfers are established. The proposed model of the fiber space is distinguished for the rich geometry of normal spaces, allowing to anticipate its further developmental possibilities.

Despite the prominent role played by open tubular columns in gas chromatography, they have enjoyed comparatively little success as supports for open tubular liquid chromatography (OTLC), owing to impractical channel diameters (3-5 μm) required to facilitate retention in the liquid phase. In an effort to circumvent the technical issues associated with such narrow diameters, columns with multiple parallel channels have been suggested as alternatives – to this end, micro-structured fibres (MSFs) have been proposed as supports for OTLC. Much research has been conducted using MSFs for chromatography in the Oleschuk group, and although some success has been achieved, performance has been continuously hindered by flow velocity variation among the channels stemming from differences in channel sizes (or channel variance) as well as differences in stationary phase coverage, which serve to degrade column efficiency. Recent efforts have focused on devising a novel method for assessing the channel variance of MSFs. This method seeks to determine hole tolerance through evaluation of the extent of band broadening that occurs when performing chromatography in the absence of a retentive mechanism. Using this method, a linear correlation between the relative standard deviation of the channel diameters and the amount of broadening was revealed. To supplement the results, computational fluid dynamics was employed to simulate fluid flow through multi-channel columns. The results of these simulations again provided a linear correlation between the RSD of the channel diameters and the extent of flow velocity variation among the channels. / Thesis (Master, Chemistry) -- Queen's University, 2012-08-15 11:57:28.915

No description available.

The use of fibre-reinforced polymer matrix composite materials is growing at a faster rate than GDP in many countries. An improved understanding of their processing and mechanical behaviour would extend the potential applications of these materials. For unidirectional composites, it is predicted that localised absence of fibres is related to longitudinal compression failure. The use of woven reinforcements permits more effective manufacture than for unidirectional fibres. It has been demonstrated experimentally that compression strengths of woven composites are reduced when fibres are clustered. Summerscales predicted that clustering of fibres would increase the permeability of the reinforcement and hence expedite the processing of these materials. Commercial fabrics are available which employ this concept using flow-enhancing bound tows. The net effect of clustering fibres is to enhance processability whilst reducing the mechanical properties. The effects reported above were qualitative correlations. Gross differences in the appearance of laminate sections are apparent for different weave styles. For the quantification of subtle changes in fabric architecture, the use of automated image analysis is essential. Griffm used Voronoi tessellation to measure the microstructures of composites made using flow-enhancing tows. The data was presented as histograms with no single parameter to quantify microstructure. This thesis describes the use of automated image analysis for the measurement of the microstructures of woven fibre-reinforced composites, and pioneers the use of fractal dimensions as a single parameter for their quantification. It further considers the process-property- structure relationships for commercial and experimental fabric reinforcements in an attempt to resolve the processing versus properties dilemma. A new flow-enhancement concept has been developed which has a reduced impact on laminate mechanical properties.

No description available.

The effect of orientation and crystallinity of certain polymers, polyethylene, polypropylene, polyethylene terephthalate (PET) and poly (ether ether ketone) (PEEK) , upon the extent and nature of plasma oxidation was studied. It was found that increasing the extent of surface ordering lessened susceptibility to plasma oxidation and reduced the subsequent decay of surface treatment. The surface ageing of plasma oxidised PEEK was extensively studied with regards to the transient increase in hydrophilicity that has been observed after plasma modification. The decay and transient increase in hydrophilicity were found to be dependent upon crystallinity and storage temperature. An estimate of the activation energies for processes leading to the increase in contact angle after plasma modification were calculated and found to suggest that these processes were rotational reorganisations at the surface as opposed to migrational reorganisations. The decay of other plasma modified surfaces revealed that plasma oxidised PET and plasma fluorinated PEEK both underwent transitional reorganisations at the surface, however no such change was observed for ammonia plasma treated PEEK. Plasma modification of carbon fibres was investigated with regards to improving composite performance. Microwave plasma treatments were found to be as good as standard commercial treatments. Graphitic carbon was investigated as a model for carbon fibre surfaces, however, the plasma modified surface was found to age more readily and to be too labile for useful comparison.