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Autogenous shrinkage is of concern in high performance concrete mixtures, when specific properties like strength and durability are enhanced. Factors like low watercement ratio, low porosity and increased hydration kinetics which are associated with high performance concrete mixtures are also responsible for the development of autogenous shrinkage. With about two decades of research into autogenous shrinkage, uncertainties still exist with testing procedure, effect of supplementary cementitious materials, modelling and prediction of autogenous shrinkage. The primary focus of this study is to understand mechanisms which have been postulated to cause autogenous shrinkage like chemical shrinkage and self desiccation. In addition, this study has considered properties like porosity and internal empty voids in the analysis of the causes of bulk volume deformations of the cementitious paste systems with and without mineral admixtures. The study begins with an experimental investigation of chemical shrinkage in hydrating cementitious paste systems with the addition of fly ash, slag and silica fume using the test method recently accepted by the ASTM. This was followed by the experimental investigation of autogenous shrinkage in cementitious paste. The autogenous shrinkage in paste mixtures is studied from an early age (~1.5 hours after addition of water) for cementitious systems at a water-cementitious ratio of 0.32 (w/c 0.25 for limited mixture proportions). A non-contact measurement method using eddy current sensors were adopted. The hydration mechanism of the cementitious paste systems was then modelled using CEMHYD3D, which is a 3 dimensional numerical modelling method successfully used to study, simulate and present the hydration developments in cementitious systems. Properties like chemical shrinkage, degree of hydration, total porosity and free water content; all of which have been obtained from the CEMHYD3D simulation have been cross correlated with the experimental results in order to more comprehensively understand the mechanism contributing to bulk volume change under sealed conditions. The experimental investigations are extended to study the development in concrete with and without mineral admixtures (i.e., silica fume, fly ash and slag). Self desiccation driving the development of autogenous shrinkage has been used extensively across literature but as an alternative the author has proposed using internal drying factor in modelling autogenous shrinkage. The "internal drying factor" is described as the ratio of the empty voids (due to chemical shrinkage) to the total porosity at any point of time of hydration. Independent of the mixture proportions, a linear trend was observed between the autogenous shrinkage strain and increase in internal drying factor. Thus the internal drying factor could be incorporated into semiempirical models while attempting to predict autogenous shrinkage. An increase in the compressive strength of matured concrete at 1 year had a strong correlation to the observed autogenous shrinkage strains irrespective of the cementitious system. It is believed this could be because of the increase in gel-space ratio which is intern linked to the degree of hydration and porosity of the microstructure. The author has obtained strong evidence that the micro-structural changes associated with high strength and durable concrete have a direct impact on the autogenous shrinkage of concrete. Hence, the author suggests that autogenous shrinkage should be investigated and allowable values be stipulated as design criterion in structures that use high strength-high performance concrete.

L’objectif de cette thèse est d’élargir la gamme des composés issus des aziridine-2-carboxylates, obtenues par leur utilisation comme matière première pour la synthèse d’azahétérocycles ciblés diversement substitués, via des réactions d’ouvertures nucléophiles et d’expansions de cycle. La synthèse d’hétérocycles azotés fluorés originaux sera abordée à partir d’aziridines-2-carboxylates trifluorométhylées ainsi que d’aminoalcools et aminoacides trifluorométhylés enantiopures. Les aziridines-2-carboxylates trifluorométhylées dont la synthèse à déjà été décrite dans la littérature conduiront à des hétérocycles fluorés variés selon des réactions d’ouverture et d’agrandissement de cycles faisant intervenir les méthodologies mise au point en série non fluorée par le partenaire Tunisien. Les aminoalcools et aminoacides trifluorométhylés conduiront également à des hétérocycles de type oxazolidinones. Les nouveaux hétérocycles synthétisés trouveront des applications en tant qu’unités pseudo-peptidiques utiles en chimie des peptides. / Our purpose in this thesis is to widen the range of compounds from aziridine-2-carboxylate, which obtained by its use as a feedstock for the synthesis of new hétérocycles through nucleophilic reactions openings and expansions cycle.The synthesis of fluorinated heterocycles will be approached from aziridine-2-carboxylate trifluorométhylées and amino alcohols and amino acids trifluoromethylated enantiopure.Fluorinated aziridines whose synthesis has already been described in the literature will lead to various fluorinated heterocycles according reactions and opening cycles of expansion methodologies involving setting the nonfluorinated series developed by the Tunisian partner.The new synthesized heterocycles find applications as chiral pseudo-peptide units useful in peptide chemistry.

The following report is an investigation of growth strategies for charter management organizations. The report begins with an overview of the School Choice Movement and its introduction of market forces into the public education system. Drawing from the private, nonprofit and education sectors, the report introduces three existing frameworks for organizational growth and new market entry. The report evaluates the robustness of each of these frameworks as well as their applicability to charter school expansion through the lens of a case-study investigation of IDEA Public Schools’ expansion from the Rio Grande Valley to the Austin, Texas education market. The report concludes by introducing a new, cross-sector framework for charter expansion that brings together the strengths of existing models as well as the lessons learned from the IDEA case. The framework consists of four phases: pre-expansion, geographic market selection, growth mechanism selection and implementation. / text

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Sustainable Built Environments Senior Capstone Project / In a society growing towards alternative modes of transportation, this study explores the phase 2 streetcar expansion for the Tucson area. Using case studies and research articles, a criteria of factors were created to best judge three predetermined expansion routes. A case study was then done on these routes to determine which route would be best for the area. In this study, the factors that were looked at and used to rank the three routes included; population density and average annual income of the surrounding area of the route (400 meter buffer), accessibility and connectivity, which includes; bus stops, bike lanes, walkability, traffic counts and possible park & ride development. The last factor used in the case study was proximity to destination, specifically how many ‘big destinations’ (destinations that experience high volumes of people) each route had. The proximity to destination factor also determined how good of a balance each route had with housing, work and amenities/leisure destinations.

“The charm of history and its enigmatic lesson consist in the fact that, from age to age, nothing changes and yet everything is completely different.” – Aldous Huxley Aldous Huxley perfectly captures the elusive nature of how difficult it is to analyze history to gain insight to the present and future. Especially because the recent exponential growth in information and technology seem to be changing how the world operates. In actuality though, the same patterns continue to reappear. This paper strives to look back and first understand on a macroeconomic level what causes the business cycle of expansion and recession. Particularly, what historically triggers recessions and what are the consequences of those recessions? Using this historical knowledge, this paper will leave the reader with a better understanding of how a company can grow and thrive in the current difficult economic climate. Even though the expansion/recession cycle is still prevalent today, the affects of these swings during the 1980’s and 1990’s were dramatically reduced in what historians call “The Great Moderation”. The potential reasons for this moderation will be examined and their validity evaluated. This historical perspective combined with an understanding of more recent events allows for this paper to create recommendations for companies to help navigate the stormy economic waters ahead as we try to recover from the current recession. These recommendations hinge on policy advisors and politicians heeding the advice of the past. Lastly, I will explore potential alternate outcomes given poor fiscal and legislative policy by the ruling elite. / text

<p>It is difficult to generalize the interconnection of the three themes when using a qualitative method. But the analysis made for each theme and conclusion is both interesting and informative. Throughout the thesis focus will be on the three cross-cutting themes that constitute our purpose. These themes are: Globalization, Expansion and Corporate Culture, and we will look into their interconnection. Focus will be on how IKEA handles external changes, changes due to globalization and expansion, and how these issues affect the corporate culture of IKEA. Everything will then be compiled in chapter six, where we also created a model to demonstrate our own conclusions.</p>

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