For the last ten years, DVD-R media have played an important role in the storage of large amounts of digital data throughout the world. During this time it was assumed that the DVD-R was as long-lasting and stable as its predecessor, the CD-R. Several reports have surfaced over the last few years questioning the DVD-R's ability to maintain many of its claims regarding archival quality life spans. These reports have shown a wide range of longevity between the different brands. While some DVD-Rs may last a while, others may result in an early and unexpected failure. Compounding this problem is the lack of information available for consumers to know the quality of the media they own. While the industry works on devising a standard for labeling the quality of future media, it is currently up to the consumer to pay close attention to their own DVD-R archives and work diligently to prevent data loss. This research shows that through accelerated aging and the use of logistic regression analysis on data collected through periodic monitoring of disc read-back errors it is possible to accurately predict unrecoverable failures in the test discs. This study analyzed various measurements of PIE errors, PIE8 Sum errors, POF errors and jitter data from three areas of the disc: the whole disc, the region of the disc where it first failed as well as the last half of the disc. From this data five unique predictive equations were produced, each with the ability to predict disc failure. In conclusion, the relative value of these equations for end-of-life predictions is discussed.

The critically important nature of radical and radical ion mechanisms in biology and chemistry continues to be recognized as our understanding of these unique transient species grows. The work presented herein demonstrates the versatility of kinetic studies for understanding the elementary chemical reactions of radicals and radical ions. Chapter 2 discusses the use of direct ultrafast kinetics techniques for investigation of crucially important enzymatic systems; while Chapter 3 demonstrates the value of indirect competition kinetics techniques for development of synthetic methodologies for commercially valuable classes of compounds. The mechanism of decay for aminyl radical cations has received considerable attention because of their suspected role as intermediates in the oxidation of tertiary amines by monoamine oxygenases and the cytochrome P450 family of enzymes. Radical cations are believed to undergo deprotonation as a key step in catalysis. KIE studies performed by previous researchers indicate N,N-dimethylaniline radical cations deprotonate in the presence of the bases acetate and pyridine. By studying the electrochemical kinetics of the reaction of para substituted N,N-dimethylaniline radical cations with acetate anion, we have produced compelling evidence to the contrary. Rather than deprotonation, acetate reacts with N,N-dimethylaniline radical cation by electron transfer, generating the neutral amine and acetoxyl radical. Transport properties of reactants and solvent polarity changes were investigated and confirmed not to influence the electrochemical behavior forming the basis for our mechanistic hypothesis. To reconcile our conclusion with earlier results, KIEs were reinvestigated electrochemically and by nanosecond laser flash photolysis. Rather than a primary isotope effect (associated with C-H bond cleavage), we believe the observed KIEs are secondary, and can be rationalized on the basis of a quantum effect due to hyperconjugative stabilization in aromatic radical cations during an electron transfer reaction. Product studies performed by constant potential coulometry indicate N,N-dimethylaniline radical cations are catalytic in carboxylate oxidations. Collectively, our results suggest that aminyl radical cation deprotonations may not be as facile as was previously thought, and that in some cases, may not occur at all. Interest in design and synthesis of selenium containing heterocycles stems from their ability to function as antioxidants, anti-virals, anti-inflammatories, and immunomodulators. To establish synthetic feasibility of intramolecular homolytic substitution at selenium for preparation of selenocycles, we set out to determine what factors influence cyclization kinetics. A series of photochemically labile Barton and Kim esters have been syntheisized and employed as radical precursors. The effect of leaving radical stability on kinetics has been investigated through determination of rate constants and activation parameters for intramolecular homolytic substitution of the corresponding radicals via competition experiments. Notable leaving group effects on measured kinetic parameters show more facile reactions for radical precursors with more stable leaving radicals. Moreover, cyclizations to form six-membered (as opposed to five- membered) ring systems exhibited order of magnitude decreases in rate constants for a given leaving radical. Our results are congruent with expectations for radical cyclizations trends for the varied experimental parameters and suggest homolytic substitution affords a convenient means for synthesis of selenocycles. / Ph. D.

This thesis, conducted in collaboration with IKEA Components, explores the rate-temperature dependence of polyoxymethylene (POM) thermoplastic using dynamic mechanical thermal analysis (DMTA). A force-controlled DMTA study was carried out, and the experimental data were processed to derive the complex, storage, and loss modulus. Master curves were constructed using the time-temperature superposition (TTS) method, comparing the Arrhenius and William-Landel-Ferry (WLF) equations. Additionally, a master curve was manually created by shifting isothermal material properties. This manual curve was then compared to those generated using standard equations. The study found that the storage modulus was the dominant phenomenon in POM, with the loss modulus showing distortion likely due to measurement noise. Results indicated a slight softening of the storage modulus with increased cyclic loading. The manually constructed master curve was more coherent compared to those derived from the Arrhenius and WLF equations.

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Commercial fuels are mixtures with large numbers of components. Continuous thermodynamics is a technique for modelling fuel mixtures using a probability density function rather than dealing with each discreet component. The mean and standard deviation of the distribution are then used to model the chemical reactions of the mixture. This thesis develops the necessary theory to apply the technique of continuous thermodynamics to the oxidation reactions of hydrocarbon fuels. The theory is applied to three simplified models of hydrocarbon oxidation: a global one-step reaction, a two-step reaction with CO as the intermediate product, and the four-step reaction of Müller et al. (1992), which contains a high- and a low-temperature branch. These are all greatly simplified models of the complex reaction kinetics of hydrocarbons, and in this thesis they are applied specifically to n-paraffin hydrocarbons in the range from n-heptane to n-hexadecane. The model is tested numerically using a simple constant pressure homogeneous ignition problem using Cantera and compared to simplified and detailed mechanisms for n-heptane. The continuous thermodynamics models are able not only to predict ignition delay times and the development of temperature and species concentrations with time, but also changes in the mixture composition as reaction proceeds as represented by the mean and standard deviation of the distribution function. Continuous thermodynamics is therefore shown to be a useful tool for reactions of multicomponent mixtures, and an alternative to the "surrogate fuel" approach often used at present.

Ionic conductivity of solid polymer electrolytes (SPEs) can be enhanced by the addition of fillers, while maintaining good chemical stability, and compatibility with popular cathode and anode materials. Additionally, polymer composite electrolytes can replace the flammable organic liquid in a lithium-ion battery design and are compatible with lithium metal. Compatibility with Li-metal is a key development towards a next-generation rechargeable Li-ion battery, as a Li-metal anode has a specific capacity an order of magnitude higher than LiC6 anodes used today in everyday devices. The addition of fillers is understood to suppress the crystalline fraction in the polymer phase, increasing the ionic conductivity, as Li-ion conduction is most mobile through the amorphous phase. A full model for a conduction mechanism has not yet constructed, as there is evidence that a semi-crystalline PEO-based electrolyte performs better than a fully amorphous electrolyte. Furthermore, it is not yet fully understood why the weight load of fillers in PCEs can range from 2.5%wt to 52.5%wt, in order to achieve high ionic conductivity (~10-4S/cm). This work seeks to investigate the conduction mechanism in the PCE through the use of doped-Li7La3Zr2O12 as a filler and analysis of the PCE microstructure. In this work, a solid-state electrolyte, doped-Li7La3Zr2O12 (LLZO) was synthesized via a sol-gel method, and characterized. The effect of doping and co-doping the Li, La and Zr sites in the LLZO garnet was investigated. A PEO-based polymer composite electrolyte (PCE) was prepared by adding bismuth doped LLZO (Li7-xLa3Zr2-xBixO12) as a filler. The bismuth molar ratio was changed in value to study the dopant role on the bulk PCE ionic conductivity, polymer phase crystallinity and microstructure. Results suggest that small variations in dopant can determine the optimal weight load of filler at which the maximum ionic conductivity is reached. By understanding the relationship between filler properties and electrochemical properties, higher performance can be achieved with minimal filler content, lowering manufacturing costs a solid-state rechargeable Li-ion battery.<br>