Airborne Wind Shear Detection and Warning Systems. Second Combined Manufacturers' and Technologists' Conference, part 1

The Second Combined Manufacturers' and Technologists' Conference hosted jointly by NASA Langley (LaRC) and the Federal Aviation Administration (FAA) was held in Williamsburg, Virginia, on October 18 to 20, 1988. The purpose of the meeting was to transfer significant, ongoing results gained during the second year of the joint NASA/FAA Airborne Wind Shear Program to the technical industry and to pose problems of current concern to the combined group. It also provided a forum for manufacturers to review forward-look technology concepts and for technologists to gain an understanding of the problems encountered by the manufacturers during the development of airborne equipment and the FAA certification requirements

Polarimetric Synthetic Aperture Radar

This open access book focuses on the practical application of electromagnetic polarimetry principles in Earth remote sensing with an educational purpose. In the last decade, the operations from fully polarimetric synthetic aperture radar such as the Japanese ALOS/PalSAR, the Canadian Radarsat-2 and the German TerraSAR-X and their easy data access for scientific use have developed further the research and data applications at L,C and X band. As a consequence, the wider distribution of polarimetric data sets across the remote sensing community boosted activity and development in polarimetric SAR applications, also in view of future missions. Numerous experiments with real data from spaceborne platforms are shown, with the aim of giving an up-to-date and complete treatment of the unique benefits of fully polarimetric synthetic aperture radar data in five different domains: forest, agriculture, cryosphere, urban and oceans

Remote Sensing Observations of Tundra Snow with Ku- and X-band Radar

Seasonal patterns of snow accumulation in the Northern Hemisphere are changing in response to variations in Arctic climate. These changes have the potential to influence global climate, regional hydrology, and sensitive ecosystems as they become more pronounced. To refine our understanding of the role of snow in the Earth system, improved methods to characterize global changes in snow extent and mass are needed. Current space-borne observations and ground-based measurement networks lack the spatial resolution to characterize changes in volumetric snow properties at the scale of ground observed variation. Recently, radar has emerged as a potential complement to existing observation methods with demonstrated sensitivity to snow volume at high spatial resolutions (< 200 m). In 2009, this potential was recognized by the proposed European Space Agency Earth Explorer mission, the Cold Regions High Resolution Hydrology Observatory (CoReH2O); a satellite based dual frequency (17.2 and 9.6 GHz) radar for observation of cryospheric variables including snow water equivalent (SWE). Despite increasing international attention, snow-radar interactions specific to many snow cover types remain unevaluated at 17.2 or 9.6 GHz, including those common to the Canadian tundra. This thesis aimed to use field-based experimentation to close gaps in knowledge regarding snow-microwave interaction and to improve our understanding of how these interactions could be exploited to retrieve snow properties in tundra environments. Between September 2009 and March 2011, a pair of multi-objective field campaigns were conducted in Churchill, Manitoba, Canada to collect snow, ice, and radar measurements in a number of unique sub-arctic environments. Three distinct experiments were undertaken to characterize and evaluate snow-radar response using novel seasonal, spatial, and destructive sampling methods in previously untested terrestrial tundra environments. Common to each experiment was the deployment of a sled-mounted dual-frequency (17.2 and 9.6 GHz) scatterometer system known as UW-Scat. This adaptable ground-based radar system was used to collect backscatter measurements across a range of representative tundra snow conditions at remote terrestrial sites. The assembled set of measurements provide an extensive database from which to evaluate the influence of seasonal processes of snow accumulation and metamorphosis on radar response. Several advancements to our understanding of snow-radar interaction were made in this thesis. First, proof-of-concept experiments were used to establish seasonal and spatial observation protocols for ground-based evaluation. These initial experiments identified the presence of frequency dependent sensitivity to evolving snow properties in terrestrial environments. Expanding upon the preliminary experiments, a seasonal observation protocol was used to demonstrate for the first time Ku-band and X-band sensitivity to evolving snow properties at a coastal tundra observation site. Over a 5 month period, 13 discrete scatterometer observations were collected at an undisturbed snow target where Ku-band measurements were shown to hold strong sensitivity to increasing snow depth and water equivalent. Analysis of longer wavelength X-band measurements was complicated by soil response not easily separable from the target snow signal. Definitive evidence of snow volume scattering was shown by removing the snowpack from the field of view which resulted in a significant reduction in backscatter at both frequencies. An additional set of distributed snow covered tundra targets were evaluated to increase knowledge of spatiotemporal Ku-band interactions. In this experiment strong sensitivities to increasing depth and SWE were again demonstrated. To further evaluate the influence of tundra snow variability, detailed characterization of snow stratigraphy was completed within the sensor field of view and compared against collocated backscatter response. These experiments demonstrated Ku-band sensitivity to changes in tundra snow properties observed over short distances. A contrasting homogeneous snowpack showed a reduction in variation of the radar signal in comparison to a highly variable open tundra site. Overall, the results of this thesis support the single frequency Ku-band (17.2 GHz) retrieval of shallow tundra snow properties and encourage further study of X-band interactions to aid in decomposition of the desired snow volume signal.4 month

Polarimetric Synthetic Aperture Radar, Principles and Application

Demonstrates the benefits of the usage of fully polarimetric synthetic aperture radar data in applications of Earth remote sensing, with educational and development purposes. Includes numerous up-to-date examples with real data from spaceborne platforms and possibility to use a software to support lecture practicals. Reviews theoretical principles in an intuitive way for each application topic. Covers in depth five application domains (forests, agriculture, cryosphere, urban, and oceans), with reference also to hazard monitorin

Ecohydrological impacts of climate change on a riparian chalk valley wetland

This thesis assesses the impacts of climate change on the CEH River Lambourn Observatory, Boxford, UK. This comprises a 10 ha chalk valley, riparian wetland and 600 m of the River Lambourn, designated for its conservation value and scientific interest. A field campaign targeted knowledge gaps in previous research to enable development of a conceptual model of hydrological functioning. The physically based, distributed model MIKE SHE was chosen to simulate hydrology due to flexibility in process representation and proven applicability to wetland hydrology. Model results were consistent with field observations and confirmed the conceptual model. Findings showed that groundwater/surface-water interaction dominates hydrological processes. Channel head boundaries broadly control water levels across the wetland. Areas of groundwater upwelling control discrete head elevations and contain high concentrations of nitrate. These support confined growth of Carex paniculata surrounded by poor fen communities in reducing higher-phosphate waters. In-channel macrophyte growth and its management through cutting acutely affect water levels. Impacts of climate change were assessed by driving the MIKE SHE model with projected changes in hydrometeorological inputs for the 2080s, derived from UKCP09. Areas of groundwater upwelling caused amplified response of water levels at distinct locations. Simulated water levels were linked to requirements of the MG8 plant community and Desmoulin’s whorl snail (Vertigo moulinsiana). Impacts on each differed spatially, in line with hydrological impacts. The PHABSIM habitat modelling methodology was modified to assess river habitat response for brown trout (Salmo trutta), using outputs from the 1D hydraulic component of MIKE SHE, MIKE 11. Reductions in habitat availability were pronounced through periods of low flows, more so for adult than juvenile trout. Different hydrological requirements for species in distinct areas of the site support separate management strategies. Multiple objective management may be achieved through adaptive modification of the current management regime

An experimental investigation into the effectiveness of steel fibre-reinforced concrete relative to conventional mesh-reinforced concrete in thin shell construction

Includes bibliographical references.This report presents the results of an investigation into the suitability of steel-fibre reinforced concrete (SFRC) as a building material. The performance of the SFRC is gauged relative to conventional steel mesh-reinforced concrete. The report begins with the historical background of fibre-reinforcing, its development and diversity in modern times. The theoretical principles governing the strength of SFRC are formulated, followed by an extensive review of factors influencing the fibre's potential and its subsequent effect on the mechanical properties of a concrete matrix. The experimental program is thereafter detailed in two stages: the "Efficiency and Proving Phase" followed by the "Application Phase". The former involves a series of tests to determine the most promising fibre of the five types available, while the latter compares the strength properties of slabs and arches reinforced with this fibre to those reinforced with wire mesh. The test results obtained from the two phases are evaluated and discussed in the succeeding two sections and the report ends with the conclusions drawn and recommendations regarding the effectiveness of SFRC relative to mesh-reinforced concrete

Gender construction and the individual in the work of Mona Caird

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Radiation Simulation for Air and Oxy-fuel Combustion using Computational Fluid Dynamics

Coal consumption is predicted to account for about 21% of the total global primary energy in 2040 and this continues to be a challenge for global warming and air pollution. Oxyfuel combustion is one of the leading options for carbon capture and storage (CCS) technologies to reduce the impact on the environment. Initially this technology has been studied successfully on small-scale facilities but it needs to be developed for large-scale applications. CFD has been demonstrated to be a key tool for the development and optimisation of pulverised coal combustion processes and it is still an important tool for new designs and retro-fitting of conventional power plants for oxyfuel combustion. Radiation heat transfer plays an important role, influencing the overall combustion efficiency, pollutant formation and flame ignition and propagation. This thesis focuses on the radiation properties of the particles as well as gas property models on the overall influence of the prediction of the formation of NOx pollutants in pulverised coal combustion. The radiative properties of the particles are investigated with a focus on the effect of the optical properties and approximate solutions to determine the radiative properties, with different experimental data for the optical properties and approximate solutions being employed. The effects of the radiative properties on the radiative heat transfer are investigated in three dimensional enclosures for small and large-scale furnaces and implemented on a 250 kW pilot scale combustion for both air and oxyfuel conditions. The results from the study highlights the best selection for the particle properties for simulations in small and large-scale pulverised coal furnaces and employing radiation models for the gases and particles to improve the NOx predictions in pulverised coal combustion under air and oxy-fired environments

Third International Symposium on Space Mission Operations and Ground Data Systems, part 1

Under the theme of 'Opportunities in Ground Data Systems for High Efficiency Operations of Space Missions,' the SpaceOps '94 symposium included presentations of more than 150 technical papers spanning five topic areas: Mission Management, Operations, Data Management, System Development, and Systems Engineering. The papers focus on improvements in the efficiency, effectiveness, productivity, and quality of data acquisition, ground systems, and mission operations. New technology, techniques, methods, and human systems are discussed. Accomplishments are also reported in the application of information systems to improve data retrieval, reporting, and archiving; the management of human factors; the use of telescience and teleoperations; and the design and implementation of logistics support for mission operations