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Load capacity predictions of continuous concrete deep beams reinforced with GFRP barsShalookh, Othman H. Zinkaah, Ashour, Ashraf 26 February 2019 (has links)
Yes / Nine continuous concrete deep beams reinforced with glass fibre reinforced polymer (GFRP) bars were experimentally tested to failure. Three main parameters were investigated, namely, shear span-to-overall depth ratio, web reinforcement and size effect. The experimental results confirmed the impacts of web reinforcement and size effect that were not considered by the strut-and-tie method (STM) of the only code provision, the Canadian S806-12, that addressed such elements. The experimental results were employed to evaluate the applicability of the methods suggested by the American, European and Canadian codes as well as the previous studies to predict the load capacities of continuous deep beams reinforced with GFRP bars. It was found that these methods were unable to reflect the influences of size effect and/or web reinforcement, the impact of which has been confirmed by the current experimental investigation. Therefore, a new effectiveness factor was recommended to be used with the STM. Additionally, an upper-bound analysis was developed to predict the load capacity of the tested specimens considering a reduced bond strength of GFRP bars. A good agreement between the predicted results and the experimental ones was obtained with the mean and coefficient of variation values of 1.02 and 5.9%, respectively, for the STM and 1.03 and 8.6%, respectively, for the upper-bound analysis. / Higher Committee of Education Development in Iraq (HCED)
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L-phenylalanine preloading reduces the 10B(n,α)7Li dose to the normal brain by inhibiting the uptake of boronophenylalanine in boron neutron capture therapy for brain tumours. / L-フェニルアラニンの前投与はホウ素中性子捕捉療法に用いるボロノフェニルアラニンの正常脳の取り込みを抑制するWatanabe, Tsubasa 23 March 2017 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第20227号 / 医博第4186号 / 新制||医||1019(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 増永 慎一郎, 教授 宮本 享, 教授 伊佐 正 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM
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Effect of nutrient momentum and mass transport on membrane gradostat reactor efficiencyGodongwana, Buntu January 2016 (has links)
Thesis submitted in fulfilment of the requirements for the degree Doctor technologiae (engineering: chemical) In the faculty of engineering at the cape peninsula university of technology / Since the first uses of hollow-fiber membrane bioreactors (MBR’s) to immobilize whole cells were reported in the early 1970’s, this technology has been used in as wide ranging applications as enzyme production to bone tissue engineering. The potential of these devices in industrial applications is often diminished by the large diffusional resistances of the membranes. Currently, there are no analytical studies on the performance of the MBR which account for both convective and diffusive transport. The purpose of this study was to quantify the efficiency of a biocatalytic membrane reactor used for the production of enzymes. This was done by developing exact solutions of the concentration and velocity profiles in the different regions of the membrane bioreactor (MBR). The emphasis of this study was on the influence of radial convective flows, which have generally been neglected in previous analytical studies. The efficiency of the MBR was measured by means of the effectiveness factor.
An analytical model for substrate concentration profiles in the lumen of the MBR was developed. The model was based on the solution of the Navier-Stokes equations and Darcy’s law for velocity profiles, and the convective-diffusion equation for the solute concentration profiles. The model allowed for the evaluation of the influence of both hydrodynamic and mass transfer operating parameters on the performance of the MBR. These parameters include the fraction retentate, the transmembrane pressure, the membrane hydraulic permeability, the Reynolds number, the axial and radial Peclet numbers, and the dimensions of the MBR. The significant findings on the hydrodynamic studies were on the influence of the fraction retentate. In the dead-end mode it was found that there was increased radial convective flow, and hence more solute contact with the enzymes/biofilm immobilised on the surface of the membrane. The improved solute-biofilm contact however was only limited to the entrance half of the MBR. In the closed shell mode there was uniform distribution of solute, however, radial convective flows were significantly reduced. The developed model therefore allowed for the evaluation of an optimum fraction retentate value, where both the distribution of solutes and radial convective flows could be maximised.
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L'efficacité de la gestion des ressources humaines en contexte de gestion de projet de systèmes d'informationCipresso, Bruno January 2008 (has links)
Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.
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L'efficacité de la gestion des ressources humaines en contexte de gestion de projet de systèmes d'informationCipresso, Bruno January 2008 (has links)
Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal
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Synthèse et évaluation catalytique de cristaux creux de zéolithe Y / Synthesis and catalytic performance of hollow Y zeolite crystalsPagis, Céline 03 October 2018 (has links)
Les zéolithes sont des aluminosilicates cristallisés possédant une microporosité organisée et régulière de dimension moléculaire. Plus particulièrement, les zéolithes de type structural FAU sont très employées dans l’industrie comme tamis moléculaires, adsorbants ou catalyseurs grâce à leur faible coût de fabrication, leur grand volume poreux et leur large taille de pores. Cependant, leurs canaux purement microporeux limitent grandement la diffusion de molécules lors de réactions catalytiques ce qui affecte directement les vitesses de réaction et réduit la fraction utile de chaque cristal. L’objectif de cette thèse a été de créer une cavité interne (macroporosité) au sein de chaque cristal de zéolithe Y dont la taille globale et l’épaisseur de parois permettront de réduire les problèmes de diffusion tout en gardant des solides facilement manipulables. Durant cette étude, deux stratégies ont été imaginées et brevetées : la première consiste à préparer des capsules polycristallines de zéolithe Y en faisant croitre des nanocristaux de zéolithe Y en périphérie de cristaux de zéolithe Beta servant directement de nutriment et se détruisant au cours de la synthèse. La seconde stratégie consiste à éliminer le coeur de chaque cristal d’une zéolithe Y par une méthode de dissolution préférentielle. Une méthode multi-étapes alliant désalumination et désilication sélectives a été développée et a permis d’obtenir des monocristaux creux de zéolithe Y. Ensuite, dans le but de tester leurs propriétés diffusionnelles et catalytiques, ces deux nouveaux matériaux ont été imprégnés de nanoparticules de platine puis utilisés dans des réactions modèles d’hydrogénation et d’hydro-isomérisation. Dans le cas des monocristaux creux, ces réactions ont permis de mettre en évidence l’influence positive de la morphologie et plus particulièrement de la longueur de diffusion sur l’activité et l’efficacité catalytiques de ces nouveaux matériaux / Zeolites are crystalline microporous aluminosilicates whose structure contains channels, voids and cavities of molecular dimensions. Zeolites with FAU framework type are extensively used as molecular sieves, adsorbents or catalysts thanks to their low fabrication cost, their high porous volume and their large pore size. However, the intrinsic microporosity of these solids often imposes molecular diffusion limitations due to hindered access and slow intra-crystalline transport. The objective of this PhD thesis was to synthetize hollow Y zeolite crystals with an internal cavity (macroporosity) and walls sufficiently thin to reduce significantly diffusion limitations while preventing handling issues. During the PhD, two strategies have been developed to synthetize these materials. The first one consists in the synthesis of polycrystalline capsules of zeolite Y by overgrowing Y nanocrystals onto Beta zeolite crystals that serve as template as well as nutrients. The second strategy involves the selective removal of the core of each zeolite Y crystals through a multi-step original method combining dealumination and selective desilication. Stating from a standard NaY zeolite, this strategy enables effective preparation of hollow single crystals with well controlled morphology and composition. The influence of the morphology on diffusion and catalytic properties was estimated by comparing the activity of the platinum-impregnated new materials with those of bulk analogs in hydrogenation and hydro-isomerization model reactions. In the case of hollow single crystals, these reactions enable to highlight the positive influence of the morphology and particularly of the diffusion path length on the catalytic efficiency and activity of these new materials
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Behaviour of continuous concrete deep beams reinforced with GFRP barsShalookh, Othman H. Zinkaah January 2019 (has links)
This research aims to investigate the behaviour of glass fibre reinforced
polymer bars (GFRP) reinforced continuous concrete deep beams. For this
purpose, experimental, analytical and numerical studies were conducted.
Nine continuous concrete deep beams reinforced with GFRP bars and one
specimen reinforced with steel bars were experimentally tested to failure. The
investigated parameters included shear span-to-overall depth ratio (𝑎/ℎ), size
effect and web reinforcement ratio. Two 𝑎/ℎ ratios of 1.0 and 1.7 and three
section heights of 300 mm, 600 mm and 800 mm as well as two web
reinforcement ratios of 0% and 0.4% were used. The longitudinal
reinforcement, compressive strength and beam width were kept constant at
1.2%, ≈55 MPa and 175 mm, respectively. The web reinforcement ratio
achieved the minimum requirements of the CSA S806-12. The experimental
results highlighted that the web reinforcement ratio improved the load
capacities by about 10% and 18% for specimens having 𝑎/ℎ ratios of 1.0 and
1.7, respectively. For specimens with web reinforcement, the increase of 𝑎/ℎ
ratio from 1.0 to 1.7 led to reductions in the load carrying capacity by about
33% and 29% for beams with overall depths of 300 mm and 600 mm,
respectively. Additionally, a considerable reduction occurred in the shear
strength due to the increase of the section depth from 300 mm to 600 mm. The
experimental results confirmed the impacts of web reinforcement and size
effect that were not considered by the strut-and-tie method (STM) of the only
code provision, the Canadian S806-12, that addressed such elements.
In this study, the STM was illustrated and simplified to be adopted for GFRP
RC continuous deep beams, and then, the experimental results obtained from
this study were employed to assess the performance of the effectiveness
factors suggested by the STMs of the American (ACI 318-2014), European
(EC2-04) and Canadian (S806-12) codes as well as those factors
recommended by the previous studies to predict the load capacities. It was
found that these methods were unable to reflect the influences of member size
and/or web reinforcement reasonably, the impact of which has been confirmed
by the current experimental investigation. Therefore, a new effectiveness
factor was recommended to be used with the STM. Additionally, an upper bound analysis was developed to predict the load capacities of the tested specimens considering a reduced bond strength of GFRP bars after assessing
the old version recommended for steel RC continuous deep beams. A good
agreement between the predicted results and the measured ones was
obtained with the mean and coefficient of variation values for
experimental/calculated results of 1.02 and 5.9%, respectively, for the STM
and 1.03 and 8.6%, respectively, for the upper-bound analysis.
A 2D finite element analysis using ABAQUS/Explicit approach was carried out
to introduce a model able to estimate the response of GFRP RC continuous
deep beams. Based on the experimental results extracted from the pullout
tests, the interface between the longitudinal reinforcement and concrete
surface was modelled using a cohesive element (COH2D4) tool available in
ABAQUS. Furthermore, a perfect bond between the longitudinal reinforcement
and surrounding concrete was also modelled to evaluate the validity of this
assumption introduced by many previous FE studies. To achieve a reasonable
agreement with the test results, a sensitivity analysis was implemented to
select the proper mesh size and concrete model variables. The suitability and
capability of the developed FE model were demonstrated by comparing its
predictions with the test results of beams tested experimentally. Model
validation showed a reasonable agreement with the experiments in terms of
the failure mode, total failure load and the load-deflection responses. The
perfect bond model has overestimated the predicted results in terms of
stiffness behaviour and failure load, while the cohesive element model was
more suitable to reflect the behaviour of those specimens. The validated FE
model was then employed to implement a parametric study for the key
parameters that govern the behaviour of beams tested and to achieve an in depth understanding of such elements. The parametric study showed that the
higher the 𝑎/ℎ ratio the more pronounced the effect of web and the longitudinal
reinforcements and the lower the effect of concrete compressive strength; and
vice versa when 𝑎/ℎ ratio reduces.
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