1,128 research outputs found

    Computer-Controlled Programmable Pulse Generator for a JEOL JNM-FT-1A Radio Frequency Amplifier Section of a Nuclear Magnetic Resonance Spectrometer

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    A microprocessor controlled programmable pulse generator was specifically designed to interface with the JEOL JNM-FT-1 A Radio Frequency (RF) section of a nuclear magnetic resonance (NMR) spectrometer. The programmable pulse generator was programmed and controlled by an IBM compatible computer. Statis rams were utilized as the programmable pulse generator\u27s on board memory which were used to store the pulse sequences. Pulse widths can be programmed from 0.2 microseconds to 14.3 minutes. The JEOL RF section is unique in that it allows the pulse generator to control the phase of the RF transmitted to the NMR probe and whether the sample will be decoupled. These two items set this programmable pulse generator apart from other pulse generators described in the literature and those systems which are commercially available. This programmable pulse generator was constructed to replace the old JEOL thumb wheel controlled pulse generator. Typical 180 degree pulse lengths for the JEOL NMR are approximately 20 microseconds

    Reed Canarygrass for Gully Control

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    For many Iowa farmers, reed canarygrass is most valuable for pasture on poorly drained soils where other palatable grasses won\u27t grow. But for healing and controlling gullies, reed canarygrass is unexcelled

    Birdsfoot Trefoil for in Iowa

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    Is birdsfoot trefoil a new legume

    Campus Vol VI N 4

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    Pierson, Pete. Untitled. Cartoon. 2. Hawk, Pete. The First Big Snow . Prose. 3. Smith, Orlo. A Day In the Life of Miss Campus . Picture. 5. Pierson, Pete. Old Seniors never Die... Cartoon. 8. Cole, Sam H. King . Just a Hobo . Prose. 10. Johnson, C. P. Some Sons Of Denison . Prose. 12. Anonymous. Last Will and Testament of the Senior Class . Prose. 14. Kat, Kitty. Untitled. Prose. 16. Spartan. Untitled. Prose. 16. Shaft. Untitled. Prose. 16. Pointer. Untitled. Prose. 16. Tarnation. Untitled. Prose. 17. Sundial. Untitled. Prose. 17. Pup. Untitled. Prose. 17. Aggrevator. Untitled. Prose. 17. Gander, Green. Untitled. Prose. 17. Mis-A-Sip. Untitled. Prose. 17. Lyke. Untitled. Prose. 17

    In vivo Spectroscopic and Imaging Studies of Photosensitizer in Photodynamic Therapy

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    Photodynamic Therapy (PDT) has emerged as a useful cancer treatment modality which utilizes a tumor localizing dye and activating light to selectively destroy neoplastic tissue. In an effort to understand the newly synthesized photosensitizers, we are studying them in a mouse tumor model grown on the dorsal side of the foot by in vivo magnetic resonance techniques. We have synthesized several photosensitizers which are specifically labeled with fluorine. Several coils appropriate for the tumor study by 19F NMR were designed and constructed for this project. The solenoid coil tunable to both 1Hand 19F nuclei was used to monitor the 19F labeled photosensitizer in the mouse foot tumor. An in vivo 19F NMR technique was used to study the retention of the photosensitizer over time in the tumor. We have used 31P NMR to study the outcome of PDT after using the new photosensitizer

    From Earth to Orbit: An assessment of transportation options

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    The report assesses the requirements, benefits, technological feasibility, and roles of Earth-to-Orbit transportation systems and options that could be developed in support of future national space programs. Transportation requirements, including those for Mission-to-Planet Earth, Space Station Freedom assembly and operation, human exploration of space, space science missions, and other major civil space missions are examined. These requirements are compared with existing, planned, and potential launch capabilities, including expendable launch vehicles (ELV's), the Space Shuttle, the National Launch System (NLS), and new launch options. In addition, the report examines propulsion systems in the context of various launch vehicles. These include the Advanced Solid Rocket Motor (ASRM), the Redesigned Solid Rocket Motor (RSRM), the Solid Rocket Motor Upgrade (SRMU), the Space Shuttle Main Engine (SSME), the Space Transportation Main Engine (STME), existing expendable launch vehicle engines, and liquid-oxygen/hydrocarbon engines. Consideration is given to systems that have been proposed to accomplish the national interests in relatively cost effective ways, with the recognition that safety and reliability contribute to cost-effectiveness. Related resources, including technology, propulsion test facilities, and manufacturing capabilities are also discussed

    Effect of Molybdenum on the Corrosion Behavior of High-Entropy Alloys CoCrFeNi 2

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    The corrosion behavior of high-entropy alloys (HEAs) CoCrFeNi2 and CoCrFeNi2Mo0.25 was investigated in 3.5 wt. percent sodium chloride (NaCl) at 25°C by electrochemical methods. Their corrosion parameters were compared to those of HASTELLOY® C-276 (UNS N10276) and stainless steel 316L (UNS 31600) to assess the suitability of HEAs for potential industrial applications in NaCl simulating seawater type environments. The corrosion rates were calculated using corrosion current determined from electrochemical experiments for each of the alloys. In addition, potentiodynamic polarization measurements can indicate active, passive, and transpassive behavior of the metal as well as potential susceptibility to pitting corrosion. Cyclic voltammetry (CV) can confirm the alloy susceptibility to pitting corrosion. Electrochemical impedance spectroscopy (EIS) elucidates the corrosion mechanism under studied conditions. The results of the electrochemical experiments and scanning electron microscopy (SEM) analyses of the corroded surfaces revealed general corrosion on alloy CoCrFeNi2Mo0.25 and HASTELLOY C-276 and pitting corrosion on alloy CoCrFeNi2 and stainless steel 316L

    Controllability and Design of Unmanned Multirotor Aircraft Robust to Rotor Failure

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    A new design method for multi-rotor aircraft with distributed electric propulsion is presented to ensure a property of robustness against rotor failure from the control perspective. Based on the concept of null controllability, a quality measure is derived to evaluate and quantify the performance of a given design with the consideration of rotor failure. An optimization problem whose cost function is based on the quality measure is formulated and its optimal solution identifies a set of optimal design parameters that maximizes an aircraft’s ability to control its attitude and hence its position. The effectiveness of the proposed design procedure is validated through the results of experimentation with the Autonomous Flying Ambulance model being developed at Caltech’s Center for Autonomous Systems and Technologies

    Adhesion Molecule Expression in Polymorphic Light Eruption

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    Endothelial leukocyte adhesion molecule-1 (ELAM-1), vascular cell adhesion molecule-1 (VCAM-1), and intercellular adhesion molecule-1 (ICAM-1) are cytokine-regulated cell-surface Ieukocyte adhesion molecules. We have investigated the in vivo kinetics and pattern of expression of these adhesion molecules in relation to tissue accumulation of leukocytes in the photodermatosis, polymorphic light eruption (PMLE), which is characterized by dense perivascular leukocytic infiltration. Immunohistology was performed on biopsies taken at varying time points from PMLE lesions induced in 11 subjects by suberythemal solar simulated irradiation. Vascular endothelial ELAM-1 expression was first observed at 5 h, maximal at 24 to 72 h, and remained elevated at 6 d. VCAM-1, minimally expressed in control skin, was induced above background levels on endothelium and some perivascular cells after 24h and maintained at 6 d. Endothelial cell ICAM-1 expression was increased above control levels at 72h and 6 d. Keratinocyte ICAM-1 expression, most marked overlying areas of dermal leukocytic infiltration, began at 5h and was strong at 72h and 6 d. In addition to lymphocytes, significant number of neutrophils of but not eosinophils were detected in the dermal leukocytic infiltrate that appeared at 5h and persisted at 6 d. The pattern of adhesion molecule expression that we have observed is similar to that seen in normal skin during a delayed hypersensitivity reaction: These observations support an immunologic basis for PMLE

    EROSIVE WEAR OF SELECTED MATERIALS FOR FOSSIL ENERGY APPLICATIONS

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    ABSTRACT A number of materials have been evaluated to determine their erosion resistance for fossil energy applications. This is part of a larger program to study wear and corrosion at Albany Research Center. This paper will present the results for some of these materials, including FeAl, FeAl cermets, WC-Co cemented carbides, Si 3 N 4 -MoSi 2 , Si 3 N 4 , Stellite 6B, white cast irons and 440C steel. Trends in erosion rates due to material properties and erosive conditions will be presented. FeAl cermets performed well compared to the WC-Co cemented carbides. The interparticle spacing of the WC-Co cemented carbides correlated with the erosion rate. The erosion rate of the WC-Co cemented carbides decreased as the interparticle spacing decreased. It is important to realize that erosion resistance is not an intrinsic material property, but is a system response. A change in the wear environment can significantly alter the relative rankings of materials with respect to their wear rate. For example, at relatively low velocities, the carbides in the white cast irons are more erosion resistant than the matrix, while at higher velocities the matrix is more erosion resistant
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