9,285 research outputs found

    Comparison of ERTS-1 and Skylab-EREP for interdisciplinary coastal investigations

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    The author has identified the following significant results. NASA's ERTS-1 satellite and Skylab EREP have both provided imagery suitable for investigating coastal vegetation, land use, current circulation, water turbidity, waste disposal, and sea state. Based on high contrast targets, such as piers and breakwaters, the ERTS-1 MSS seems to have a resolution of 70-100 meters, Skylab's S190A about 30-70 meters, and its S190B about 10-30 meters. Important coastal land use details can be more readily mapped using Skylab's imagery. On the other hand, the regular eighteen day cycle of ERTS-1 allows observation of important manmade and natural changes, and facilitates collection of ground truth. The Skylab/EREP multispectral scanner offers 13 spectral bands as compared to 4 bands on ERTS-1. However, EREP scanner tapes require special filtering to remove several types of noise and their conical line scan pattern must be linearized before one can identify small targets based on spatial features

    Skylab and ERTS-1 investigations of coastal land use and water properties

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    The author has identified the following significant results. ERTS-1 multispectral scanner and Skylab's S190A, S190B, and S192 data products were evaluated for their utility in studying current circulation, suspended sediment concentrations and pollution dispersal in Delaware Bay and in mapping coastal vegetation and land use. Imagery from the ERTS-1 MSS, S190A and S190B cameras shows considerable detail in water structure, circulation, suspended sediment distribution and within waste disposal plumes in shelf waters. These data products were also used in differentiating and mapping twelve coastal vegetation and land use classes. The spatial resolution of the S190A multispectral facility appears to be about 30 to 70 meters while that of the S190B earth terrain camera is about 10 to 30 meters. Such resolution, along with good cartographic quality, indicates a considerable potential for mapping coastal land use and monitoring water properties in estuaries and on the continental shelf. The ERTS-1 MSS has a resolution of about 70-100 meters. Moreover, its regular 18-day cycle permits observation of important changes, including the environmental impact of coastal zone development on coastal vegetation and ecology

    Application of LANDSAT-2 to the Management of Delaware's Marine and Wetland Resources

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    The author has identified the following significant results. The duPont waste disposal plume was observed in 12 NASA/LANDSAT satellite images during dump up to 54 hours after dump. The circulation processes at the acid waste disposal site are highly event-dominated, with the majority of the water transport occurring strong northeasters. There is a mean flow to the south alongshore. During the warm months, the ocean stratifies with warm water over cold water. During stratified conditions, the near-bottom drogues showed very little movement. LANDSAT, aircraft, and boats were used successfully to study estuarine and coastal fronts or boundaries. By capturing and holding oil slicks, frontal systems significantly influence the movement and dispersion of oil slicks in Delaware Bay. Recent oil slick tracking experiments conducted to verify a predictive oil dispersion and movement model have shown that during certain parts of the tidal cycle the oil slicks tend to line up along boundaries

    Magnetic resonance imaging (MRI) of heavy-metal transport and fate in an artificial biofilm

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    Unlike planktonic systems, reaction rates in biofilms are often limited by mass transport, which controls the rate of supply of contaminants into the biofilm matrix. To help understand this phenomenon, we investigated the potential of magnetic resonance imaging (MRI) to spatially quantify copper transport and fate in biofilms. For this initial study we utilized an artificial biofilm composed of a 50:50 mix of bacteria and agar. MRI successfully mapped Cu2+ uptake into the artificial biofilm by mapping T2 relaxation rates. A calibration protocol was used to convert T2 values into actual copper concentrations. Immobilization rates in the artificial biofilm were slow compared to the rapid equilibration of planktonic systems. Even after 36 h, the copper front had migrated only 3 mm into the artificial biofilm and at this distance from the copper source, concentrations were very low. This slow equilibration is a result of (1) the time it takes copper to diffuse over such distances and (2) the adsorption of copper onto cell surfaces, which further impedes copper diffusion. The success of this trial run indicates MRI could be used to quantitatively map heavy metal transport and immobilization in natural biofilms

    Inventories of Delaware's coastal vegetation and land-use utilizing digital processing of ERTS-1 imagery

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    There are no author-identified significant results in this report

    Application of LANDSAT-2 to the management of Delaware's marine and wetland resources

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    The author has identified the following significant results. The problem of remote sensing of suspended matter in water was analyzed in terms of the single scattering albedo, and a semiempirical relationship between satellite radiance measurements and the concentration of suspended matter in the water was developed. The relationship was tested using data from the 7 July 1973 LANDSAT overpass of Delaware Bay with good results

    Identification of marsh vegetation and coastal land use in ERTS-1 imagery

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    Coastal vegetation species appearing in the ERTS-1 images taken of Delaware Bay on August 16, and October 10, 1972 have been correlated with ground truth vegetation maps and imagery obtained from high altitude RB-57 and U-2 overflights. The vegetation maps of the entire Delaware Coast were prepared during the summer of 1972 and checked out with ground truth data collected on foot, in small boats, and from low-altitude aircraft. Multispectral analysis of high altitude RB-57 and U-2 photographs indicated that five vegetation communities could be clearly discriminated from 60,000 feet altitude including: (1) salt marsh cord grass, (2) salt marsh hay and spike grass, (3) reed grass, (4) high tide bush and sea myrtle, and (5) a group of fresh water species found in impoundments built to attract water fowl. All of these species are shown in fifteen overlay maps, covering all of Delaware's wetlands prepared to match the USGS topographic map size of 1:24,000

    Energy efficient transport technology: Program summary and bibliography

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    The Energy Efficient Transport (EET) Program began in 1976 as an element of the NASA Aircraft Energy Efficiency (ACEE) Program. The EET Program and the results of various applications of advanced aerodynamics and active controls technology (ACT) as applicable to future subsonic transport aircraft are discussed. Advanced aerodynamics research areas included high aspect ratio supercritical wings, winglets, advanced high lift devices, natural laminar flow airfoils, hybrid laminar flow control, nacelle aerodynamic and inertial loads, propulsion/airframe integration (e.g., long duct nacelles) and wing and empennage surface coatings. In depth analytical/trade studies, numerous wind tunnel tests, and several flight tests were conducted. Improved computational methodology was also developed. The active control functions considered were maneuver load control, gust load alleviation, flutter mode control, angle of attack limiting, and pitch augmented stability. Current and advanced active control laws were synthesized and alternative control system architectures were developed and analyzed. Integrated application and fly by wire implementation of the active control functions were design requirements in one major subprogram. Additional EET research included interdisciplinary technology applications, integrated energy management, handling qualities investigations, reliability calculations, and economic evaluations related to fuel savings and cost of ownership of the selected improvements

    Adiabatic Flip-Flops and Sequential Circuit Design using Novel Resettable Adiabatic Buffers

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    We propose novel resettable adiabatic buffers for five adiabatic logic families namely; Efficient Adiabatic Charge Recovery Logic (EACRL), Improved Efficient Charge Recovery Logic (IECRL), Positive Feedback Adiabatic Logic (PFAL), Complementary Pass-transistor Adiabatic Logic (CPAL) and Clocked Adiabatic Logic (CAL). We present the design of resettable flip-flops using the proposed buffers. The proposed flip-flops alleviate the problem of increased energy and area consumption incurred by the existing mux-based resettable flip-flops. We then design the 3-bit up-down counters and extended our comparison beyond energy dissipation using the above five adiabatic logic families. PFAL based sequential circuit designs gives the best performance trade-offs in terms of complexity, energy, speed and area compared to the other adiabatic designs
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