The transport and adsorption phenomena in cement-based materials are the most important processes in the durability of concrete structures or nuclear waste containers, as they are precursors to a number of deterioration processes such as chloride-induced corrosion, sulfate attack, carbonation, etc. Despite this importance, our understanding of these processes remains limited because the pore structure and composition of concrete are complex. In addition, the range of the pore sizes, from nanometers to millimeters, requires the multi-scale modeling of the transport and adsorption processes. Among the various environments that cement-based materials are exposed to, aqueous and saline environments represent the most common types. Therefore, this dissertation investigates the adsorption and transport phenomena of cement-based materials exposed to an aqueous and saline environment from atomic to macro-scales using different arrays of novel spectroscopic techniques and simulation methods, such as scanning transmission X-ray microscopy (STXM), X-ray absorption near edge structure (XANES), molecular dynamics (MD), and finite element method (FEM). The structure and transport of water molecules through interlayer spacing of tobermorite was investigated using MD simulations because the interlayer water of calcium silicate hydrate (C-S-H) gel influences various material properties of concrete. The adsorption processes of cementitious phases interacting with sodium and chloride ions at the nano-scale were identified using STXM and XANES measurements. A mathematical model and FEM procedure were developed to identify the effect of surface treatments at macro-scale on ionic transport phenomena of surface-treated concrete. Finally, this dissertation introduced a new material, calcined layered double hydroxide (CLDH), to prevent chloride-induced deterioration.

The categories of space and time are crucial variables in the constitution of what many scholars deem as modernity. However, due to the almost exclusive interpretation of space and time as components of a modernity coupled with global capitalism (Harvey, Jameson), discussions of a socialist space and time as a construction of an alternate modernity during the 60s and 70s—in particular across the Third World—have been neglected. Julius Nyerere’s project of collectivation, or ujamaa, in Tanzania during this period is a prime example of an attempt to develop the nation state outside of the capitalist format. While it would be interesting to explore the connections Nyerere had with other socialist Third World countries like China within the international context and their attempts at nation building, this paper will focus on an analysis of the Tanzanian government’s decision in 1973 to move the capital of the country from the Eastern port city of Dar es Salaam, to the more centrally located Dodoma. The questions of primary importance are: How did moving the Tanzanian capital from Dar es Salaam to Dodoma in 1973 embody Nyerere’s vision of socialist African development? Or more specifically, how did the socialist urban planning of Dodoma fit into the greater project of ujamaa and rural development? And finally, how was the planned construction of a new urban capital an attempt at a definition of socialist space and time?

This note shows that a very simple model can generate returns that resemble most of the temporal and distributional behavior of long returns surprisingly well. The model is based on the stochastic unit root process introduced in Granger and Swanson (1997).