4,215 research outputs found
A project to evaluate moisture stress in corn and soybean areas of western and southwestern Minnesota
Remote sensing techniques, particularly LANDSAT data, were used to assess soil moisture stress through crop signature in southwestern Minnesota. Related objectives were: localization of droughty, well drained, and poorly drained soils; detection of stress from hail, wind, and disease damage; and the use of remote sensing data for agricultural management. Since the amount and distribution of precipitation were adequate during the 1977 and 1978 growing seasons, no significant stress occurred. Crop conditions were very favorable. As a result, crop signatures were too uniform to reflect soilscape variations and crop condition changes. In 1979 precipitation was again adequate to excess, particularly in June and August. In some cases, poorly drained sites especially, stress conditions developed as a result of excess of water and could be identified on color infrared photographs
Modeling scenarios for water allocation in the Gediz Basin, Turkey
Water management / Water allocation / Models / River basin development / Hydrology / Decision making / Environmental effects / Water use efficiency / Climate / Irrigation water / Irrigated farming / Stream flow / Surface water / Salt water intrusion / Turkey / Gediz Basin
Water management for sustainable irrigated agriculture in the Zayandeh Rud Basin, Esfahan Province, Iran
Irrigation systemsCropping systemsIrrigated farmingRiver basinsTopographyGeomorphologyClimateHydrologyWater qualityGroundwaterSoil salinitySustainable agricultureIranEsfahan ProvinceZayandeh Rud BasinChadegan Reservoir
Application of ERTS-1 imagery to state wide land information system in Minnesota
There are no author-identified significant results in this report
Evolution of helicity in NOAA 10923 over three consecutive solar rotations
We have studied the evolution of magnetic helicity and chirality in an active
region over three consecutive solar rotations. The region when it first
appeared was named NOAA10923 and in subsequent rotations it was numbered NOAA
10930, 10935 and 10941. We compare the chirality of these regions at
photospheric, chromospheric and coronal heights. The observations used for
photospheric and chromospheric heights are taken from Solar Vector Magnetograph
(SVM) and H_alpha imaging telescope of Udaipur Solar Observatory (USO),
respectively. We discuss the chirality of the sunspots and associated H_alpha
filaments in these regions. We find that the twistedness of superpenumbral
filaments is maintained in the photospheric transverse field vectors also. We
also compare the chirality at photospheric and chromospheric heights with the
chirality of the associated coronal loops, as observed from the HINODE X-Ray
Telescope.Comment: 8 pages, 4 figure
Signal specific electric potential sensors for operation in noisy environments
Limitations on the performance of electric potential sensors are due to saturation caused by environmental electromagnetic noise. The work described involves tailoring the response of the sensors to reject the main components of the noise, thereby enhancing both the effective dynamic range and signal to noise. We show that by using real-time analogue signal processing it is possible to detect a human heartbeat at a distance of 40 cm from the front of a subject in an unshielded laboratory. This result has significant implications both for security sensing and biometric measurements in addition to the more obvious safety related applications
The role of the spin in quasiparticle interference
Quasiparticle interference patterns measured by scanning tunneling microscopy
(STM) can be used to study the local electronic structure of metal surfaces and
high temperature superconductors. Here, we show that even in non-magnetic
systems the spin of the quasiparticles can have a profound effect on the
interference patterns. On Bi(110), where the surface state bands are not
spin-degenerate, the patterns are not related to the dispersion of the
electronic states in a simple way. In fact, the features which are expected for
the spin-independent situation are absent and the observed interference
patterns can only be interpreted by taking spin-conserving scattering events
into account.Comment: 4 pages, 2 figure
Role of the electric field in surface electron dynamics above the vacuum level
Scanning tunneling spectroscopy (STS) is used to study the dynamics of hot
electrons trapped on a Cu(100) surface in field emission resonances (FER) above
the vacuum level. Differential conductance maps show isotropic electron
interference wave patterns around defects whenever their energy lies within a
surface projected band gap. Their Fourier analysis reveals a broad wave vector
distribution, interpreted as due to the lateral acceleration of hot electrons
in the inhomogeneous tip-induced potential. A line-shape analysis of the
characteristic constant-current conductance spectra permits to establish the
relation between apparent width of peaks and intrinsic line-width of FERs, as
well as the identification of the different broadening mechanisms.Comment: 7 pages, 4 figures, to appear in Phys. Rev.
Application of ERTS-1 imagery to state wide land information system in Minnesota
There are no author-identified significant results in this report
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