Analysis and design of a flat central finned-tube radiator

Computer program based on fixed conductance parameter yields minimum weight design. Second program employs variable conductance parameter and variable ratio of fin length to tube outside radius, and is used for radiator designs with geometric limitations. Major outputs of the two programs are given

Hybrid thermocouple development program

The design and development of a hybrid thermocouple, having a segmented SiGe-PbTe n-leg encapsulated within a hollow cylindrical p-SiGe leg, is described. Hybrid couple efficiency is calculated to be 10% to 15% better than that of a all-SiGe couple. A preliminary design of a planar RTG, employing hybrid couples and a water heat pipe radiator, is described as an example of a possible system application. Hybrid couples, fabricated initially, were characterized by higher than predicted resistance and, in some cases, bond separations. Couples made later in the program, using improved fabrication techniques, exhibited normal resistances, both as-fabricated and after 700 hours of testing. Two flat-plate sections of the reference design thermoelectric converter were fabricated and delivered to NASA Lewis for testing and evaluation

Use of computer-aided analysis techniques for cover type mapping in areas of mountainous terrain

There are no author-identified significant results in this report

Field methods for rodent studies in Asia and the Indo-Pacific

Farm Management,

Optically probing the fine structure of a single Mn atom in an InAs quantum dot

We report on the optical spectroscopy of a single InAs/GaAs quantum dot (QD) doped with a single Mn atom in a longitudinal magnetic field of a few Tesla. Our findings show that the Mn impurity is a neutral acceptor state A^0 whose effective spin J=1 is significantly perturbed by the QD potential and its associated strain field. The spin interaction with photo-carriers injected in the quantum dot is shown to be ferromagnetic for holes, with an effective coupling constant of a few hundreds of micro-eV, but vanishingly small for electrons.Comment: 5 pages, 3 figure

Concentration for One and Two Species One-Dimensional Reaction-Diffusion Systems

We look for similarity transformations which yield mappings between different one-dimensional reaction-diffusion processes. In this way results obtained for special systems can be generalized to equivalent reaction-diffusion models. The coagulation (A + A -> A) or the annihilation (A + A -> 0) models can be mapped onto systems in which both processes are allowed. With the help of the coagulation-decoagulation model results for some death-decoagulation and annihilation-creation systems are given. We also find a reaction-diffusion system which is equivalent to the two species annihilation model (A + B ->0). Besides we present numerical results of Monte Carlo simulations. An accurate description of the effects of the reaction rates on the concentration in one-species diffusion-annihilation model is made. The asymptotic behavior of the concentration in the two species annihilation system (A + B -> 0) with symmetric initial conditions is studied.Comment: 20 pages latex, uuencoded figures at the en

Multiple resource evaluation of region 2 US forest service lands utilizing LANDSAT MSS data

The author has identified the following significant results. LANDSAT MSS imagery provided an excellent overview which put a geomorphic study into a regional perspective, using scale 1:250,000 or smaller. It was used for deriving a data base for land use planning for southern San Juan Mountains. Stereo pairing of adjacent images was the best method for all geomorphic mapping. Combining this with snow enhancement, seasonal enhancement, and reversal aided in interpretation of geomorphic features. Drainage patterns were mapped in much greater detail from LANDSAT than from a two deg quadrangle base

Magnetic Properties of Epitaxial and Polycrystalline Fe/Si Multilayers

Fe/Si multilayers with antiferromagnetic interlayer coupling have been grown via ion-beam sputtering on both glass and single-crystal substrates. High-angle x-ray diffraction measurements show that both sets of films have narrow Fe peaks, implying a large crystallite size and crystalline iron silicide spacer layers. Low-angle x-ray diffraction measurements show that films grown on glass have rougher interfaces than those grown on single-crystal substrates. The multilayers grown on glass have a larger remanent magnetization than the multilayers grown on single-crystal substrates. The observation of magnetocrystalline anisotropy in hysteresis loops and $(hkl)$ peaks in x-ray diffraction demonstrates that the films grown on MgO and Ge are epitaxial. The smaller remanent magnetization in Fe/Si multilayers with better layering suggests that the remanence is not an intrinsic property.Comment: 9 pages, RevTex, 4 figures available by fax. Send email to [email protected] for more info. Submitted to '95 MMM proceeding

Observing non-classical crystallisation processes in gypsum via infrared attenuated total reflectance spectroscopy

The nature of crystallisation processes is of major interest, as they are among the most frequently occurring reactions associated with a variety of relevant processes in chemistry, biochemistry, and geochemistry. In this study, an innovative approach towards fundamentally understanding crystallisation pathways in a seemingly simple system-gypsum-has been developed via infrared spectroscopic techniques. Specifically, infrared attenuated total reflection spectroscopy (IR-ATR) was instrumental in revealing detailed information on inter- and intramolecular interactions during gypsum crystallization via subtle changes in the vibrational spectra of the involved reactants. When applying D2O as an isotope marker, it was shown that isotopically labelled water may serve as a viable spectroscopic probe during mid-infrared (3-15 µm) studies providing unique insight into the crystallization process at molecular-level detail. In addition, it was revealed that H2O and D2O give rise to distinctly different reaction kinetics during the crystallization process