673 research outputs found

    1990 Kentucky Winter Annual Legume Variety Test

    Get PDF
    Cover crops are often used in Kentucky following the harvest of row crops such as tobacco, corn, and soybeans. Living cover crops can prevent erosion, reduce leaching of nutrients, and supply grazing, green manure, or a plant cover in which to no-till the following spring

    1990 Kentucky Red Clover Variety Test

    Get PDF
    Red clover is a high quality, shortlived perennial legume that is used in mixed or pure stands for pasture, hay, silage, green chop, and soil improvement. This species is adapted to a wide range of climatic and soil conditions and therefore is very versatile as a forage crop. Stands are generally productive for two or three years with the highest yields occurring in the year following establishment. Red clover is used primarily as a renovation legume for grass pastures. It is the dominant legume in Kentucky because it is high in seedling vigor, quality, yield, and animal acceptance

    Phase II Study of Ifosfamide+Doxorubicin in Patients With Advanced Synovial Sarcomas (E1793): A Trial of the Eastern Cooperative Oncology Group

    Get PDF
    Purpose Because we had observed in the synovial sarcoma subgroup of a broad phase III advanced soft tissue sarcoma study a significantly greater objective regression rate from ifosfamide+doxorubicin (88%) than from doxorubicin alone (20%) (P = 0.02), the Eastern Cooperative Oncology Group (ECOG) decided to further assess this two drug combination in a subsequent Phase II study

    Deployment Technology of a Heliogyro Solar Sail for Long Duration Propulsion

    Get PDF
    Interplanetary, multi-mission, station-keeping capabilities will require that a spacecraft employ a highly efficient propulsion-navigation system. The majority of space propulsion systems are fuel-based and require the vehicle to carry and consume fuel as part of the mission. Once the fuel is consumed, the mission is set, thereby limiting the potential capability. Alternatively, a method that derives its acceleration and direction from solar photon pressure using a solar sail would eliminate the requirement of onboard fuel to meet mission objectives. MacNeal theorized that the heliogyro-configured solar sail architecture would be lighter, less complex, cheaper, and less risky to deploy a large sail area versus a masted sail. As sail size increases, the masted sail requires longer booms resulting in increased mass, and chaotic uncontrollable deployment. With a heliogyro, the sail membrane is stowed as a roll of thin film forming a blade when deployed that can extend up to kilometers. Thus, a benefit of using a heliogyro-configured solar sail propulsion technology is the mission scalability as compared to masted versions, which are size constrained. Studies have shown that interplanetary travel is achievable by the heliogyro solar sail concept. Heliogyro solar sail concept also enables multi-mission missions such as sample returns, and supply transportation from Earth to Mars as well as station-keeping missions to provide enhanced warning of solar storm. This paper describes deployment technology being developed at NASA Langley Research Center to deploy and control the center-of-mass/center-of-pressure using a twin bladed heliogyro solar sail 6-unit (6U) CubeSat. The 6U comprises 2x2U blade deployers and 2U for payload. The 2U blade deployers can be mounted to 6U or larger scaled systems to serve as a non-chemical in-space propulsion system. A single solar sail blade length is estimated to be 2.4 km with a total area from two blades of 720 m2; total allowable weight of a 6U CubeSat is approximately 8 kg. This makes the theoretical characteristic acceleration of approximately 0.75 mm/s2 at I AU (astronomical unit), when compared to IKAROS (0.005 mm/s2) and NanoSail-D (0.02 mm/s2)

    Spectral Engineering of Optical Fiber Preforms Through Active Nanoparticle Doping

    Get PDF
    Europium doped alkaline earth fluoride [Eu:AEF2 (AE = Ca, Sr, Ba)] nanoparticles were synthesized and systematically incorporated into the core of modified chemical vapor deposition (MCVD)-derived silica-based preforms by solution doping. The resulting preforms were examined to determine the impact of the nanoparticles chemistry on the spectroscopic behavior of the glass. The dominant existence of Eu3+ was demonstrated in all preforms, which is in contrast to conventional solution doped preforms employing dissolved europium salts where Eu2+ is primarily observed. Raman spectroscopy and fluorescence lifetime measurements indicated that the nanoparticles composition is effective in controlling, at a local chemical and structural level, the spectroscopic properties of active dopants in optical fiber glasses. Further, there is a systematic and marked increase in radiative lifetime, τ, of the Eu3+ emission that follows the cationic mass; τCa \u3c τSr \u3c τBa with the BaF2-derived sample yielding a 37% lengthening of the lifetime over the CaF2-derived one. Such nanoscale control of what otherwise is silica glass could be useful for realizing property-enhanced and tailored spectroscopic performance from otherwise “standard” materials, e.g., vapor-derived silica, in next generation optical fibers

    Spectral engineering of optical fiber preforms through active nanoparticle doping

    Get PDF
    Europium doped alkaline earth fluoride [Eu:AEF(2) (AE = Ca, Sr, Ba)] nanoparticles were synthesized and systematically incorporated into the core of modified chemical vapor deposition (MCVD)-derived silica-based preforms by solution doping. The resulting preforms were examined to determine the impact of the nanoparticles chemistry on the spectroscopic behavior of the glass. The dominant existence of Eu3+ was demonstrated in all preforms, which is in contrast to conventional solution doped preforms employing dissolved europium salts where Eu2+ is primarily observed. Raman spectroscopy and fluorescence lifetime measurements indicated that the nanoparticles composition is effective in controlling, at a local chemical and structural level, the spectroscopic properties of active dopants in optical fiber glasses. Further, there is a systematic and marked increase in radiative lifetime, tau, of the Eu3+ emission that follows the cationic mass; tau(Ca) \u3c tau(Sr) \u3c tau(Ba) with the BaF2-derived sample yielding a 37% lengthening of the lifetime over the CaF2-derived one. Such nanoscale control of what otherwise is silica glass could be useful for realizing property-enhanced and tailored spectroscopic performance from otherwise standard materials, e.g., vapor-derived silica, in next generation optical fibers
    corecore