8,843 research outputs found
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
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
Überprüfung der Bezugskurven der Schweizer Version des Freiburger Zahlen- und Einsilbertests
Zusammenfassung: Hintergrund: Die Schweizer Ausgabe des Freiburger Sprachverständlichkeitstests unterscheidet sich von der deutschen Version u.a. durch den Ersatz von 5 in der Schweiz ungebräuchlichen einsilbigen Testworten. Zudem wird keine Freifeldentzerrung benutzt und die die sich aus dem Freifeldübertragungsmaß ergebende Differenz von 6dB zwischen Lautsprecher und Kopfhörer wird bei der Kalibrierung nicht berücksichtigt. Der vor einiger Zeit eingeführte Pegelausgleich zwischen den Prüfworten und Anpassungen in der Kalibrierung veranlassten uns zur Überprüfung der Bezugskurven. Patienten/Methoden: Bei 20 normal hörenden Versuchpersonen wurde das Sprachverstehen von Zahlen und einsilbigen Wörtern mit Kopfhörern und Lautsprechern geprüft. Ergebnisse: Der Pegel für 50% Sprachverstehen lag bei Lautsprecherdarbietung im Mittel um 7,5dB niedriger ist als bei Kopfhörerdarbietung. Die mittlere Pegeldifferenz zwischen Zahlen und Einsilbern betrug 9,6dB, liegt also deutlich unter den 14dB der heute in der Schweiz empfohlenen Bezugskurven. Fazit: Die heute in der Schweiz empfohlenen Bezugskurven stimmen für Einsilber bei Kopfhörerdarbietung gut mit unseren Messungen überein, nicht aber für Zahlen und bei Lautsprecherdarbietun
Stickstoffnutzungseffizienz roher und anaerob vergorener Güllen: Eine Studie mit unterschiedlichen 15N Methoden
In agricultural biogas plants in Switzerland, in general 80 % or more of the digested organic matter is farmyard manure. Organic waste materials are used as cosubstrates. A field experiment with silage maize was conducted to test whether the apparent nitrogen use efficiency (NUE) of anaerobically digested slurries is higher than the one of raw slurries in the year of application. Two different 15N labelling
methods were used. In the 15N direct method, slurry NH4-N was labelled. In the indirect 15N isotope dilution method soil was pre-labelled by incorporating 15N labelled
clover-grass powder; maize received unlabelled slurry. In the 15N direct approach, raw slurries had the lowest apparent NUE of NH4-N, two anaerobically digested (AD)
slurries had an approximately 10 % higher NUE than raw slurries (not all results sign.). The NUE of total N in the non-isotopic difference calculation showed the same
patterns between treatments. In contrast, results gathered with the isotope dilution method showed different patterns. Incorporating clover-grass powder one month before maize sowing seems to be too short to pre-label the soil organic matter homogenously
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
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
Study of the general mechanism of stress corrosion of aluminum alloys and development of techniques for its detection Quarterly report, 1 Dec. 1967 - 29 Feb. 1968
Stress corrosion of aluminum alloys and techniques for its detectio
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
- …