5,719 research outputs found

    Visualizing the Geology of Lake Trout Spawning Sites: Northern Lake Michigan

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    Geologists and biologists are working together to understand the links between lake floor geology (composition and shape) and the distribution of lake trout throughout their life cycle. Lake floor geology is one of the main factors determining where lake trout spawn, feed, and hide. In support of ongoing research to study Lake Michigan trout habitats, the U.S. Geological Survey in cooperation with the U.S. Army Corps of Engineers mapped the morphology of principle lake trout spawning sites. Using the Army Corps of Engineer\u27s SHOALS airborne lidar (Light Detection and Ranging) system we mapped six regions in Northern Lake Michigan in order to identify ideal spawning regions composed of shallow, clean, gravel/cobble substrate, adjacent to deeper water. Lidar mapping systems, which use laser pulses to measure water depths from an airplane, are now available to map the nearshore lake morphology at meter-scale detail. Maps generated from the bathymetric data are used to define regions with smooth homogeneous substrate, regions with higher relief, and mixed regions with both smooth and rough relief. This morphologic information combined with sediment samples and direct bottom observations enable geologists to map areas with rougher relief composed of rock outcrop, boulders, and cobbles, as well as smooth regions covered with sand or mud. This information helps biologists, fishery managers, and ecologists visualize the lake floor in significant detail which promotes better fishery management, species protection, and habitat identification. These maps present the maps and discuss the geology of the six lake trout spawning sites mapped by the lidar system. Where the mapping approached land, aerial photography of the land is combined with the bathymetric data to help visualize the scale of the offshore features. Map and perspective views of Boulder Reef, Hog Island Reef, and Little Traverse Bay are shown on sheet 1, whereas map and perspective views of Trout and High Island Shoal, Gull Island Reef, and Dahlia Shoal are shown on sheet 2. Additional information, bathymetric data, imagery, and metadata are available online athttp://geopubs.wr.usgs.gov/open-file/of03-120/

    Smart antenna beamforming network

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    Smart Antenna with RF beamforming capability can greatly improve the performance of the vehicle communication system by providing better link quality and high immunity to interference. Butler Matrix is a well-known beamforming network. It can be used for multibeam antennas. The Butler Matrix increases the system capacity and provides higher signal to interference ratio, consequently enhancing the overall system performance. Several studies have been conducted related to the cascading Butler Matrix. In an Multi Port Amplifier (MPA) application, a signal entering one port of the Butler Matrix is divided into equal parts. The signal is then amplified by all the amplifiers and then recombined by the combining Butler Matrix at the output port that corresponds to the particular input port.Suarez also reported that the introduction of the cascading Butler Matrices improves the performance of antenna parameters such as cross over and beam orthogonality

    The use of infrared spectroscopy to monitor bio-catalytic processes

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    This thesis was previously held under moratorium from 11th June 2013 until 11th June 2017.Industrial biotransformation processes are becoming increasingly important for the production of single enantiomers of both low value commodity and high value fine chemicals. Despite this demand and the regulatory authorities encouragement of a quality by design approach, the application of process analytical technology to these systems has, to date, been relatively limited. A more traditional off-line approach involving chromatographic methods is still commonly employed for the quantification of key analytes during the process. In-situ measurements tend to be limited to physical parameters of the system such as pH and dO₂, which give little information about the actual process progression. This study investigates the potential of applying infrared spectroscopic techniques to monitor and quantify the key components of de-racemisation and transaminase biotransformation processes. Multivariate models based on the near and mid infrared spectroscopic regions have been constructed for a variety of these processes. Each constructed model was subjected to an external validation procedure to ensure rigorous testing. Stoichiometric linkages were known to exist within these systems. Whilst steps were taken to ensure these linkages were broken, the contributors to each model were also carefully examined to ensure that co-linearity within the constructed models had been adequately addressed. Having constructed robust process models, mechanisms of ensuring the long-term suitability of the models were also investigated. This aimed to ensure the continued predictive ability of the constructed models following instrument maintenance, repair or replacement. Quantitative models resulted that were able to predict the key analyte concentrations of the external validation datasets over the course of the biotransformation processes. Predicted values from the constructed models were in good agreement with both the errors of calibration and cross validation associated with the models, and the actual concentrations predicted by the off-line chromatographic reference methods.Industrial biotransformation processes are becoming increasingly important for the production of single enantiomers of both low value commodity and high value fine chemicals. Despite this demand and the regulatory authorities encouragement of a quality by design approach, the application of process analytical technology to these systems has, to date, been relatively limited. A more traditional off-line approach involving chromatographic methods is still commonly employed for the quantification of key analytes during the process. In-situ measurements tend to be limited to physical parameters of the system such as pH and dO₂, which give little information about the actual process progression. This study investigates the potential of applying infrared spectroscopic techniques to monitor and quantify the key components of de-racemisation and transaminase biotransformation processes. Multivariate models based on the near and mid infrared spectroscopic regions have been constructed for a variety of these processes. Each constructed model was subjected to an external validation procedure to ensure rigorous testing. Stoichiometric linkages were known to exist within these systems. Whilst steps were taken to ensure these linkages were broken, the contributors to each model were also carefully examined to ensure that co-linearity within the constructed models had been adequately addressed. Having constructed robust process models, mechanisms of ensuring the long-term suitability of the models were also investigated. This aimed to ensure the continued predictive ability of the constructed models following instrument maintenance, repair or replacement. Quantitative models resulted that were able to predict the key analyte concentrations of the external validation datasets over the course of the biotransformation processes. Predicted values from the constructed models were in good agreement with both the errors of calibration and cross validation associated with the models, and the actual concentrations predicted by the off-line chromatographic reference methods

    A Study of Selected Aspects of Electromagnetic Formation Flight

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    Electromagnetic Formation Flight (EMFF) is a technique for electromagnetically controlling the relative position and velocity of satellites in close proximity, without using propellant.\nAn optimal design for an EMFF system for clusters of small satellites was calculated. Trends in parameters were identiï¬ ed, taking into account thermal issues.\nA power transfer system, using strongly coupled magnetic resonance, was simulated, using the same coils as the EMFF system. The eï¬ ciencies were calculated for the same parameters.\nA scheme for EMFF control was tested, in which two satellites at a time were active, with their dipoles aligned with each other on-axis. This system was shown to keep clusters of four satellites within speciï¬ ed boundaries

    Supplementary feeding of weaner sheep at Esperance

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    Cereal grains, particularly barley, have been the usual supplement fed to weaner sheep during summer and autumn along Western Australia\u27s south coast. This area is a major barley producer, and weather-damaged and other feed quality grain have a ready use. High protein lupin seed, and to a lesser extent silage, have gained wide acceptance recently as alternative supplements. This article discusses the results of the first two of a series of supplementary feeding experiments at Esperance Downs Research Station

    Concurrent dual-band high efficiency class-E power amplifier

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