The objective of this thesis is to introduce an alternative temperature sensor in CMOS technology with small area, low power consumption, and high resolution that can be easily interfaced. A novel temperature sensor utilizing the interface–trap charge pumping phenomenon and the temperature sensitivity of generation current is proposed. This thesis presents the design and characterization of the proposed temperature sensor fabricated in 0.18µm CMOS technology. The prototype sensor is characterized for the temperature range of 27oC–120oC. It has frequency output and exhibits linear transfer characteristics, high sensitivity, and high resolution. This temperature sensor is proposed for microprocessor thermal management applications.

Multiple Pseudacteon phorid fly species, including P. tricuspis and P. curvatus, have been released in the southern United States beginning in 1997 and 2003 (respectively) to serve as biological control agents against red imported fire ants Solenopsis invicta Buren (hereafter referred to as RIFA). Field research in the United States on phorid/RIFA interactions has addressed establishment and spread of released species. Additionally, studies are needed on phorid biology and ecology with respect to spatial distribution and phenology, phorid/habitat associations and phorid-mediated affects on RIFA foraging patterns. A suite of manipulative laboratory and field experiments/observations were conducted to 1) develop a novel phorid sampling device to provide uniform and repeatable sampling of flies, 2) assess spatial distributions and phenology of Pseudacteon tricuspis and P. curvatus, 3) assess P. tricuspis and P. curvatus habitat associations and 4) assess phorid-mediated affects on RIFA foraging patterns and caste ratios. PTS Traps (developed for this research) are significantly more effective than previous sampling methods in terms of mean number of flies collected, efficiency of use and % trap success. Data collected with these traps allowed for the determination of patterns of species-specific phenology and relative densities through time and speciesspecific numerical/spatial superiority (Chapter IV). P. curvatus was significantly more abundant than P. tricuspis in only one of the habitat types sampled (df (160) = 4.57, P < 0.005). P. tricuspis densities did not differ significantly among habitat type. Llaboratory experiments revealed that phorid-exposed RIFA colonies foraged less intensively diurnally (df = 1,558; P < 0.05) and more intensively nocturnally (df = 778; P < 0.05) relative to control colonies. Field data regarding this compensatory nocturnal foraging shift did not corroborate those of the laboratory work. In the field there was no significant difference in foraging intensity during nocturnal (df (18) = -0.486, P = 0.633) and diurnal (df (18) = 1.375 P = 0.186) sampling periods. Lastly, chi-square analysis of RIFA forager size-classes revealed significant differences between phorid-infested (treatment) and phorid-free (control) sites (X 2 = 6811.85, df = 3, P < 0.05) with a significantly greater proportion of small RIFA foragers at the phorid-infested site.

Cold trapped ions have many applications in quantum information science and precision metrology. In this thesis, we present progress toward two objectives involving ions confined to linear RF traps: the strong coupling of Ba+ ions with a high finesse optical cavity, and the observation of an optical nuclear transition in 229Th3+. In pursuit of the first objective, a novel high-temperture vapor cell for the spectroscopy of neutral barium was constructed. Using this vapor cell, a new technique for isotope-selective photoionization loading of Ba+ in an ion trap was developed. In pursuit of the second objective, techniques ultimately to be used in creating, trapping, and observing 229Th3+ are studied using 232Th3+. Ion traps are loaded with 232Th3+ via laser ablation of thorium targets. 232Th3+ is detected optically using laser-induced fluorescence and electronically using a channel electron multiplier. A technique for creating ablation targets from trace quantities of thorium nitrate is presented. The primary loss mechanisms of Th3+, charge exchange and chemical reactions, are studied.

Within the framework of an Institutional Partnership of the Alexander von Humboldt Foundation, the Budker Institute of Nuclear Physics Novisibirsk (BINP) and Forschungszentrum Dresden-Rossendorf worked together in a joint project devoted to the research at the coupled GDT-SHIP facility of the BINP with the focus on the study of plasma phenomena within the SHIP mirror section. The project began at July 1st, 2005 and ended on August 30th, 2008. It included work packages of significant theoretical, computational and analyzing investigations. The focus of this final report is on the presentation of results achieved whereas the work that was done is described briefly only. Chapter 2 illustrates the GDT-SHIP facility and describes shortly the planned topics of the SHIP plasma research. Chapter 3 explains the main extensions and modifications of the Integrated Transport Code System (ITCS) which were necessary for the calculations of the fast ion and neutral gas particle fields in SHIP, describes briefly the scheme of computations and presents significant results of pre-calculations from which conclusions were drawn regarding the experimental program of SHIP. In chapter 4, the theoretical and computational investigations of self-organizing processes in two-component plasmas of the GDT-SHIP device are explained and the results hitherto achieved are presented. In chapter 5, significant results of several experiments with moderate and with enhanced plasma parameters are presented and compared with computational results obtained with the ITCS. Preparing neutron measurements which are planned for neutron producing experiments with deuterium injection, Monte Carlo neutron transport calculations with the MCNP code were also carried out. The results are presented. Finally, from the results obtained within the joint research project important conclusions are drawn in chapter 6.

Fat, oil, and grease residues, food particles, solids and some kitchen wastewaters are collected in grease traps which are separate from the municipal wastewater stream. Grease traps are emptied periodically and grease trap waste (GTW) is hauled for treatment. This dissertation focuses on anaerobic co-digestion of un-dewatered (raw) GTW with municipal wastewater treatment sludge (MWS) at wastewater treatment plants. In particular, this research focuses on the biochemical methane potential of un-dewatered GTW as well as the stability and performance of anaerobic co-digestion of MWS and un-dewatered GTW. A set of modified biochemical methane potential tests was performed to determine the methane potential of un-dewatered GTW under mesophilic conditions (35 °C). Methane potential of un-dewatered GTW in this study was 606 mL CH₄/g VS [subscript added] which is less than previously reported methane potentials of 845 - 1050 mL CH₄/g VS [subscript added] for concentrated/dewatered GTW. However, the methane potential of un-dewatered GTW (606 mL CH₄/g VS [subscript added]) was more than two times greater than the 223 mL CH₄/g VS [subscript added] reported for MWS digestion alone. A comprehensive study was performed to determine the stability and performance of anaerobic co-digestion of MWS with un-dewatered GTW as a function of increasing GTW feed ratios. The performance of two semi-continuously fed anaerobic digesters at 35 °C was evaluated as a function of increasing GTW feed ratios. Anaerobic co-digestion of MWS with un-dewatered GTW at a 46% GTW feed ratio (on a volatile solids basis) resulted in a 67% increase in methane production and a 26% increase in volatile solids reduction compared to anaerobic digestion of MWS alone. On the other hand, anaerobic co-digestion of un-dewatered GTW resulted in a higher inhibition threshold (46% on VS basis) than that of dewatered GTW. These results indicate that using un-dewatered GTW instead of dewatered GTW can reduce the inhibition risk of anaerobic co-digestion of MWS and GTW. Recovery of the anaerobic digesters following upset conditions was also evaluated and semi-continuous feed of digester effluent into upset digesters yielded of the biogas production level of the undisrupted digestion. Finally, a mathematical model was used to describe the relationship between methane potential and GTW feed ratio on a VS basis. The results of this research can be used to predict methane production and identify suitable GTW feeding ratios for successful co-digestion of un-dewatered GTW and MWS. / text

Universal quantum computation requires precision control of the dynamics of qubits. Frequently accurate quantum control is impeded by systematic drifts and other errors. Compensating composite pulse sequences are a resource efficient technique for quantum error reduction. This work describes compensating sequences for ion-trap quantum computers. We introduce a Lie-algebraic framework which unifies all known fully-compensating sequences and admits a novel geometric interpretation where sequences are treated as vector paths on a dynamical Lie algebra. Using these techniques, we construct new narrowband sequences with improved error correction and reduced time costs. We use these sequences to achieve laser addressing of single trapped 40Ca+ ions, even if neighboring ions experience significant field intensity. We also use broadband sequences to achieve robust control of 171Yb+ ions even with inhomogeneous microwave fields. Further, we generalize compensating sequences to correct certain multi-qubit interactions. We show that multi-qubit gates may be corrected to arbitrary accuracy if there exists either two non-commuting controls with correlated errors or one error-free control. A practical ion-trap quantum computer must be extendible to many trapped ions. One solution is to employ microfabricated surface-electrode traps, which are well-suited for scalable designs and integrated systems. We describe two novel surface-electrode traps, one with on-chip microwave waveguides for hyperfine 171Yb+ qubit manipulations, and a second trap with an integrated high numerical aperture spherical micromirror for enhanced fluorescence collection.

AEgIS is an experiment at CERN where the goal is to directly measure the gravitational force on antimatter by producing antihydrogen. The antihydrogen will be produced by a charge exchange reaction using laser excited positronium and cold antiprotons. Having a well-characterized positron plasma with at least 108 positrons and knowing how it can be controlled is essential for the positronium production. This thesis is based on the goals of AEgIS experiment and describes the positron plasma manipulations being used in AEgIS in order to achieve the required plasma properties for the experiment. The positron system is made up by a source, a Surko trap and a Penning-Malmberg trap. This system was first optimized to increase the number of positrons. The plasma was then moved to the main traps of the experiment where it was systematically characterized in terms of lifetime, cooling efficiency and compression. Positron plasma compression in time, trapping and cooling was tested for the first time in AEgIS using a buncher and Penning-Malmberg traps respectively. In this thesis, it is shown that a compression of more than 50 % in time of the positron cloud using a buncher can be achieved. It is also shown that trapping and cooling with an efficiency of nearly 100 % in the main traps using a “V” shaped potential trap was successful. On top of that, the lifetime inside this “V” shaped potential trap was observed to be longer than 30 minutes.

No description available.

This dissertation consists of three essays on income risk and aggregate demand over the business cycle, each addressing an aspect of the Great Recession. The first chapter reframes the standard liquidity trap model to illustrate the costly feedback loop between idiosyncratic risk and aggregate demand. I first show that a liquidity trap can result from excess demand for precautionary savings in times of high uncertainty. Second, I show that the output and welfare costs of the ensuing recession depend crucially on how the drop in demand for output is translated into a reduction in demand for labor. Increased unemployment risk compounds the original rise in idiosyncratic productivity risk and reinforces precautionary motives, deepening the recession. Third, I show that increasing social insurance can raise output and welfare at the zero bound. I decompose these effects to distinguish the component unique to the liquidity trap environment and show that social insurance is most effective at the zero bound when it targets the type of idiosyncratic risk households face, which in turns depends on the labor market adjustment mechanism. The second paper offers a novel model of the connection between the consumer credit and home mortgage markets through an individual’s credit history. This paper introduces a novel justification for the home mortgage interest deduction. In an economy with both housing assets and consumer credit, the mortgage interest deduction is modeled as a subsidy for the accumulation of collateralizable assets by households who have maintained good credit. As such, the subsidy loosens participation constraints and facilitates risk-sharing. Empirical evidence and a calibration exercise reveal that the subsidy has a sizable impact on the availability of credit. The third paper assesses the role of policy uncertainty in the Great Recession. The Great Recession features substantial geographic variation in employment losses, a fact that is often presented as a challenge to uncertainty-based models of the downturn. In this paper we show that there is a substantial correlation between the distribution of employment losses and the increases in local measures of both economic and policy uncertainty. This relationship is robust across a wide range of measures. / Economics

In this collection of essays I study individuals' health related decision-making and the consequences of those decisions for health and labor market productivity.