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Reuse of record except for individual research requires license from Congressional Information Service, Inc. ; At head of title: 93d Congress, 2d session. Committee print. ; CIS Microfiche Accession Numbers: CIS 74 S382-15 ; Microfiche. ; Mode of access: Internet.

Oligotrophic catchments with short spatey streams, upland lakes and peaty soils characterise northwest European Atlantic coastal regions. These catchments are important biodiversity refuges, particularly for sensitive diadromous fish populations but are subject to changes in land use and land management practices associated with afforestation, agriculture and rural development. Quantification of the degree of catchment degradation resulting from such anthropogenic impacts is often limited by a lack of long-term baseline data in what are generally relatively isolated, poorly studied catchments. This research uses a combination of palaeolimnological (radiometrically-dated variations in sedimentary geochemical elements, pollen, diatoms and remains of cladocera), census, and instrumental data, along with hindcast estimates to quantify environmental changes and their aquatic impacts since the late 19th century. The most likely drivers of any change are also identified. Results confirm an aquatic biotic response (phyto- and zooplankton) to soil erosion and nutrient enrichment associated with the onset of commercial conifer afforestation, effects that were subsequently enhanced as a result of increased overgrazing in the catchment and, possibly, climate warming. The implications for the health of aquatic resources in the catchment are discussed Environmental Protection Agency in Ireland (ILLUMINATE 2005-W-MS-40, P.McGinnity was supported by the Beaufort Marine Research Award in Fish Population Genetics funded by the Irish Government under the Sea Change Programme.

Photonic innovation is becoming ever more important in the modern world. Optical systems are dominating shorter and shorter communications distances, LED's are rapidly emerging for a variety of applications, and solar cells show potential to be a mainstream technology in the energy space. The need for novel, energy-efficient photonic and optoelectronic devices will only increase. This work unites fundamental physics and a novel computational inverse design approach towards such innovation. The first half of the dissertation is devoted to the physics of high-efficiency solar cells. As solar cells approach fundamental efficiency limits, their internal physics transforms. Photonic considerations, instead of electronic ones, are the key to reaching the highest voltages and efficiencies. Proper photon management led to Alta Device's recent dramatic increase of the solar cell efficiency record to 28.3%. Moreover, approaching the Shockley-Queisser limit for any solar cell technology will require light extraction to become a part of all future designs.The second half of the dissertation introduces inverse design as a new computational paradigm in photonics. An assortment of techniques (FDTD, FEM, etc.) have enabled quick and accurate simulation of the "forward problem" of finding fields for a given geometry. However, scientists and engineers are typically more interested in the inverse problem: for a desired functionality, what geometry is needed? Answering this question breaks from the emphasis on the forward problem and forges a new path in computational photonics. The framework of shape calculus enables one to quickly find superior, non-intuitive designs. Novel designs for optical cloaking and sub-wavelength solar cell applications are presented.

Over the last 18 months Public Service Company of New Mexico (PNM), El Camino Real Engineering, Inc. (CRE), Los Alamos National Laboratory (LANL) and Sandia National Laboratories (SNL) have worked on the development of disturbance-free power at the medium voltage substation level. The work resulted in the Secure Bus concept, a system in which a medium voltage bus in a substation is immune to power outages and voltage sags on the utility source. The Secure Bus voltage is also immune to voltage sags resulting from faults on any distribution feeder connected to the bus. The Secure Bus concept originated from work conducted to improve power quality for large high-tech manufacturing facilities, in particular for large semiconductor manufacturing plants. For the demands on quality power of a modern facility conventional equipment is not adequate for protecting the end user. For example, the operation of conventional vacuum breakers during short circuit conditions on a feeder circuit, requiring 3 to 5 cycles for breaker opening, does not allow for fast enough current interruption to avoid a voltage dip on the main bus. A sever voltage sag could result in a shut down of sensitive equipment being supplied by the other feeder circuits, which are connected to the main bus. The circumvent the problem, a fast breaker was introduced which interrupts the short circuit before the current causes a significant voltage disturbance. To make the bus immune also to power disturbances caused by power outages, energy storage is introduced to provide the necessary energy back-up in case the primary source is not available.

In the pursuit of creating efficient CdTe p-n homojunctions, we developed iodine (I) n-type doped CdTe using Cadmium Iodide (CdI2) as a dopant in varying concentrations (1018 cm-3, 1019 cm-3 and 1020 atoms·cm-3 target concentrations) in CdTe. Iodide doped crystals were grown using a Modified Vertical Bridgman furnace (MVB). Single crystals were characterized using XRD (X-Ray Diffraction), Hall effect, IR (Infrared) Microscopy, UV-VIS-NIR (Ultraviolet-Visible-Near infrared Spectroscopy) and FTIR (Fourier Transform Infrared Spectroscopy). Partners at the National Renewable Energy Laboratory (NREL) also provided data for Hall Effect and Two Photon Excitation Time Resolved Photoluminescence (2PE TRPL) of wafers and films. Photoluminescence mapping (PL mapping) was obtained from Klar scientific, and glow discharge mass spectrometry (GDMS) for purity and final doping concentration was obtained from the National Research Council Canada. Due to poor carrier properties in the crystals as-grown, two annealing treatments were explored, in either tellurium or cadmium vapor. Homojunctions were made at NREL by depositing n-type films from these crystals on p-type single crystals, CdTe:P grown and WSU. The n-type films were created using the close-space sublimation epitaxy (CSSE) process. Herein is reported the results of the grown CdTe:I crystals and, to a lesser extent, the properties of the CdTe:I thin films formed by CSSE.

The 17th International Conference on Knowledge Management was held in the historic city of Potsdam, Germany. Since the conference was among the first post-pandemic face to face conferences, the overall theme of the 17th edition of the ICKM conference rightly focused on “Knowledge, Uncertainty and Risks: From individual to global scale†at different levels of analysis and agency. This document highlighted one of the local keynote speeches by Prof. Ortwin Renn, scientific director at the International Institute for Advanced Sustainability Studies (IASS) in Potsdam (Germany) and professor for environmental sociology and technology assessment at the University of Stuttgart.

Predicted performance during both steady state and transient reactor operation determines the steady state operating limits on LMFBRs. Unnecessary conservatism in performance predictions will not contribute to safety, but will restrict the reactor to more conservative, less economical steady state operation. The most general method for reducing analytical conservatism in LMFBR's without compromising safety is to develop, validate and apply more sophisticated computer models to the limiting performance analyses. The purpose of the on-going Natural Circulation Verification Program (NCVP) is to develop and validate computer codes to analyze natural circulation transients in LMFBRs, and thus, replace unnecessary analytical conservatism with demonstrated calculational capability.

M.S.

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