6,819 research outputs found
Data processing system for the intensity monitoring spectrometer flown on the Orbiting Geophysical Observatory-F (OGO-F) satellite
The system is discussed which was developed to process digitized telemetry data from the intensity monitoring spectrometer flown on the Orbiting Geophysical Observatory (OGO-F) Satellite. Functional descriptions and operating instructions are included for each program in the system
Automotive Stirling engine development program
The major accomplishments were the completion of the Basic Stirling Engine (BSE) and the Stirling Engine System (SES) designs on schedule, the approval and acceptance of those designs by NASA, and the initiation of manufacture of BSE components. The performance predictions indicate the Mod II engine design will meet or exceed the original program goals of 30% improvement in fuel economy over a conventional Internal Combustion (IC) powered vehicle, while providing acceptable emissions. This was accomplished while simultaneously reducing Mod II engine weight to a level comparable with IC engine power density, and packaging the Mod II in a 1985 Celebrity with no external sheet metal changes. The projected mileage of the Mod II Celebrity for the combined urban and highway CVS cycle is 40.9 mpg which is a 32% improvement over the IC Celebrity. If additional potential improvements are verified and incorporated in the Mod II, the mileage could increase to 42.7 mpg
Automotive Stirling engine development program
This is the ninth Semiannual Technical Progress Report prepared under the Automotive Stirling Engine Development Program. It covers the twenty-eighth and twenty-ninth quarters of activity after award of the contract. Quarterly Technical Progress Reports related program activities from the first through the thirteenth quarters; thereafter, reporting was changed to a Semiannual format. This report summarizes the study of higher-power kinematic Stirling engines for transportation use, development testing of Mod I Stirling engines, and component development activities. Component development testing included successful conical fuel nozzle testing and functional checkout of Mod II controls and auxiliaries on Mod I engine test beds. Overall program philosophy is outlined and data and test results are presented
Magnetic characterization of the frustrated three-leg ladder compound [(CuCl2tachH)3Cl]Cl2
We report the magnetic features of a new one-dimensional stack of
antiferromagnetically coupled equilateral copper(II) triangles. High-field
magnetization measurements show that the interaction between the copper
triangles is of the same order of magnitude as the intra-triangle exchange
although only coupled via hydrogen bonds. The infinite chain turns out to be an
interesting example of a frustrated cylindrical three-leg ladder with competing
intra- and inter-triangle interactions. We demonstrate that the ground state is
a spin singlet which is gaped from the triplet excitation.Comment: 6 pages, 9 figures, revised version submitted to Phys. Rev. B. More
information at http://obelix.physik.uni-osnabrueck.de/~schnack
Automotive Stirling Engine Development Program
Development test activities on Mod I engines directed toward evaluating technologies for potential inclusion in the Mod II engine are summarized. Activities covered include: test of a 12-tube combustion gas recirculation combustor; manufacture and flow-distribution test of a two-manifold annular heater head; piston rod/piston base joint; single-solid piston rings; and a digital air/fuel concept. Also summarized are results of a formal assessment of candidate technologies for the Mod II engine, and preliminary design work for the Mod II. The overall program philosophy weight is outlined, and data and test results are presented
Tunable Resonant Raman Scattering from Singly Resonant Single Wall Carbon Nanotubes
We perform tunable resonant Raman scattering on 17 semiconducting and 7
metallic singly resonant single wall carbon nanotubes. The measured scattering
cross-section as a function laser energy provides information about a tube's
electronic structure, the lifetime of intermediate states involved in the
scattering process and also energies of zone center optical phonons. Recording
the scattered Raman signal as a function of tube location in the microscope
focal plane allows us to construct two-dimensional spatial maps of singly
resonant tubes. We also describe a spectral nanoscale artifact we have coined
the "nano-slit effect"
Demonstration of multi-channel 80 Gbit/s integrated transmitter and receiver for wavelength-division multiplexing passive optical network and fronthauling applications
The performance evaluation of a multi-channel transmitter that employs an arrayed reflective electroabsorption modulator-based photonic integrated circuit and a low-power driver array in conjunction with a multi-channel receiver incorporating a pin photodiode array and integrated arrayed waveguide grating is reported. Due to their small footprint, low power consumption and potential low cost, these devices are attractive solutions for future mobile fronthaul and next generation optical access networks. A BER performance of <10(-9) at 10.3 Gbit/s per channel is achieved over 25 km of standard single mode fibre. The transmitter/receiver combination can achieve an aggregate bit rate of 82.4 Gbit/s when eight channels are active
Observations of the J = 2 → 1 line of carbon monoxide in the NGC 2024 nebula
Observations have been made of the J = 2 → 1 transition of 12CO and 13CO in the molecular cloud near NGC 2024. The most intense emission comes from the central regions of the nebula close to areas of high optical extinction. The source contains two hotspots, but no significant velocity gradient or line-broadening was observed. This is consistent with a model in which the emission arises mainly from the high-density interface between the expanding HII region and a neutral cloud. Measurements of the 13CO isotope indicates that τ13 > 1.7, but there is insufficient information to derive the density in the region. Analysis of data for Mon R2, however, using the radially collapsing cloud model, indicates a hydrogen density of ~2 × 104 cm-3 for that source
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