The first part of this doctorate dissertation examines the factors influencing the occurrence and costs of pinhole leak corrosion as well as the household decisions for corrosion prevention and plumbing material selection. Three mail surveys of households were used to elicit the experiences with leaks as well as the optimal corrosion prevention and material choices. Probability modeling (i.e. MNL) and linear regression analysis were used to analyze survey responses. Pinhole leak occurrences were found associated with pipe type installed, property age, pipe failure history, and dwelling distance from a water treatment plant. The number and location of pinhole leaks in the dwelling and the pipe type are associated with the financial costs of pinhole leaks. The corrosion prevention choices as well as the plumbing materials depended on the risk of corrosion and cost associated with each option. Previous experiences with pinhole leak impacted the decision for household choices. Faster responses to pinhole leak outbreaks by utility managers and policymakers in terms of advising homeowners on the best ways of responding to leaks would assist homeowners in reducing costs of pinhole leak repairs and associated damages. The second part of this document deals with the debt financing issues. Debt financing decisions are made simultaneously by lenders and borrowers. Since lenders are unable to observe directly the firms’ investment decisions, the banks offer contracts based up on firms’ observable characteristics (i.e. wealth and size) and the prevailing market conditions. When deciding on the financing decisions, firms also take into account the changes in macroeconomic variables in order to lower the cost of borrowing. As a result, the goal for this article is to examine empirically the hypothesis of the effect of the debt determinant as well as the macroeconomic variables on the debt maturity structure. A reduced form of the simultaneous financing decisions model is estimated by employing several OLS estimation methods. The empirical findings offer strong support for firms with few growth options, large, and of low quality having more long-term debt in their capital structure. There was, however, no clear support for the impact of macroeconomic variables on debt maturity as some variables were not statistically significant. / Ph. D.

Pinhole leaks in copper plumbing pipes are a big concern for the homeowners. The problem is spread across the nation and remains a threat to plumbing systems of all ages. Due to the absence of a single acceptable mechanistic theory no preventive measure is available to date. Most of the present mechanistic theories are based on analysis of failed pipe samples however an objective comparison with other pipes that did not fail is seldom made. The variability in hydraulic and water quality parameters has made the problem complex and unquantifiable in terms of plumbing susceptibility to pinhole leaks. The present work determines the spatial and temporal spread of pinhole leaks across United States. The hotspot communities are identified based on repair histories and surveys. An assessment of variability in water quality is presented based on nationwide water quality data. A synthesis of causal factors is presented and a scoring system for copper pitting is developed using goal programming. A probabilistic model is presented to evaluate optimal replacement time for plumbing systems. Methodologies for mechanistic modeling based on corrosion thermodynamics and kinetics are presented. / Master of Science

Pinhole corrosion leak in home plumbing has emerged as a significant issue. In the major water distribution system managed by municipalities and water utilities the costs are distributed among all subscribers. The home plumbing repair/replacement cost and possible water damage cost must be addressed by the home owner. There are also issues of the value of home, insurance rates, health consequences, and taste and odor problems. These issues have become major concerns to home owners. Cradle to grave life cycle assessment is becoming an integral part of industrial manufacturing. In this thesis comprehensive details pertaining to life cycle assessment are presented. Copper tubing for plumbing installations is mainly obtained from recycled copper. Various stages of copper plumbing pipe manufacturing are explained. A comprehensive synthesis of various corrosion mechanisms is presented. Particular reference is given to copper plumbing pipe corrosion. A decision support tool for replacing copper plumbing pipes is presented. The deterioration process is grouped into early, normal and late stages. Because available data reflects late stage process, an optimization, neural network and curve fitting models are developed to infer early and normal stage behavior of the plumbing system. Utilizing the inferred leak rates a non-homogeneous poisson process model is developed to generate leak arrival times. An economically sustainable replacement criterion is adopted to determine optimal replacement time. / Master of Science