ANALYZING NANOSCALE THERMAL TRANSPORT USING TIME-RESOLVED X-RAY DIFFRACTION

Classical models of thermal transport breakdown at lengthscales below a few microns in many materials, including the surfaces of bulk semiconductors. This presents difficulties in the analysis and design of small electronic devices, where unexpected thermal effects can occur such as hot spots that deteriorate performance and limit speed. Time-resolved x-ray diffraction has been proposed as one method to investigate this regime of nanoscale thermal transport, especially inside semiconductor materials where other techniques can not penetrate or yield quantitative results. Towards this goal, this thesis benchmarks a new, portable, and fast open-source x-ray dynamical diffraction code (TRXD) for strained crystals developed by DePaul University against an existing standard server-based closed-source calculation tool (GID_SL, Grazing Incidence Diffraction for Superlattices). TRXD is also validated against experimental x-ray peak lineshapes by convolving the calculation results with an appropriate instrumentation resolution function. TRXD is shown to properly predict the long time-scale classical thermal behavior of a cooling semiconductor, while revealing discrepancies at the short time-scale where new nanoscale thermal transport models are under development. A new high-resolution x-ray diffraction data set is compared to a previously published low-resolution data set, and found to give the same result for delayed thermal transport in ultrafast laser-excited 100 nm metal film on a Gallium Arsenide crystal substrate

Growing pains: how risk perception and risk communication research can help to manage the challenges of global population growth

In 2011 the global human population reached seven billion and medium variant projections indicate that it will exceed nine billion before 2045. Theoretical and empirical perspectives suggest that this growth could lead to an increase in the likelihood of adverse events (e.g., food shortages, climate change, etc.) and/or the severity of adverse events (e.g., famines, natural disasters, etc.). Several scholars have posited that the size to which the global population grows and the extent to which this growth increases the likelihood of adverse outcomes will largely be shaped by individuals� decisions (in households, organizations, Governments, etc.). In light of the strong relationship between perceived risk and decision behaviors, it is surprising that there remains a dearth of empirical research that specifically examines the perceived risks of population growth and how these perceptions might influence related decisions. In an attempt to motivate this important strand of research, this paper examines the major risks that may be exacerbated by global population growth and draws upon empirical work concerning the perception and communication of risk to identify potential directions for future research. The paper also considers how individuals might perceive both the risks and benefits of population growth and be helped to better understand and address the related issues. The answers to these questions could help humanity better manage the emerging consequences of its continuing success in increasing infant survival and adult longevit

Trends in the DoD Industrial Base

Naval Postgraduate School Acquisition Research Progra

Many Faiths of Many Regions: Continuities and Changes Among Religious Adherents Across U.S. Counties

U.S. religious bodies continue to vary by their geographic distribution and their rates of growth. The changing landscape of religious adherence has many implications for communities on myriad issues (e.g., health, policy, social change). An examination of recently tabulated county-level numbers of religious adherents shows Evangelical Protestants continuing to grow, but at slower rates than that of the population. Mainline Protestants continue to decrease, even in areas of some population growth. Catholics are increasing slightly, but likely only because of Hispanic and immigrant population influxes. Precisely comparable trend data on total Jewish population growth are not readily available, but there appears to have been a considerable redistribution of the Jewish population in recent decades. Earlier county-level on other non-Christian religions is not available, but recent data show Muslims concentrated in large metropolitan counties and Eastern religious congregations concentrated in counties with Asian populations. This paper examines these changes and distributions of religious populations in light of existing theories that could account for these variations. The recent results confirm some of these theories, but suggest further examination or possible modifications for others. Further analysis of these data may also yield some insights on the interplay between political and religious population change, as well as on efforts to meet social needs through faith-based institutions.