1,302 research outputs found
Detecting slope deformation using two-pass differential interferometry:Implications for landslide studies on Earth and other planetary bodies
No full textLandslide features have been identified on Earth and the Moon, Mars, Venus, as well on the Jovian moons. By focusing on a terrestrial landslide complex we test the operational parameters of RADARSAT-1 and the use of two-pass differential interferometry to detect change, to map its extent, and to measure the amount of movement over a given time period. RADARSAT-1 was chosen because of its variable imaging modes and geometry. For investigations of landslide motions using remote sensing techniques, repeat-pass data are required. Synthetic aperture radar (SAR) interferometry (InSAR) can ideally monitor movements across the whole surface of a landslide to a millimeteric precision, yielding a coverage significantly better than that obtained by ground instrumentation. Obtaining optimal data for InSAR analysis requires controlled orbital characteristics and imaging geometries, an understanding of the landslide characteristics and behavior, a cooperative surface, and mitigation of the factors that can affect phase. Using two-pass differential interferometry, a slope deformation map has been generated from RADARSAT-1 data for part of the Black Ven landslide (2°52′W, 50°40′N), on the south coast of England. Four months separate the InSAR pair during which time 0.03 m of subsidence was measured. From this a movement rate of 0.09 m/yr can be calculated. This agrees well with ground observations and an in situ record of movement, thus demonstrating that the technique can be used to investigate landslides. With further refinement it can provide more direct measurements of landslide deformation on Earth and other planetary bodies than are currently available
Components of learning and assessment in linear algebra
No full textLinear algebra provides theory and technology that are the cornerstones of\ud
a range of cutting edge mathematical applications, from designing\ud
computer games to complex industrial problems, as well as more traditional\ud
applications in statistics and mathematical modelling. Once past\ud
introductions to matrices and vectors, the challenges of balancing theory,\ud
applications and computational work across mathematical and statistical\ud
topics and problems are considerable, particularly given the diversity of\ud
abilities and interests in typical cohorts. This paper considers two such\ud
cohorts in a second level linear algebra course in different years. The\ud
course objectives and materials were almost the same, but some changes\ud
were made in the assessment package. In addition to considering effects of\ud
these changes, the links with achievement in first year courses are analysed,\ud
together with achievement in a following computational mathematics\ud
course. Some results that may initially appear surprising provide insight\ud
into the components of student learning in linear algebra
SAR Interferometry in landslide monitorino: experience from Black Ven Landslide, Dorset 2001
No full text
The use of surface monitoring data for the interpretation of landslide movement patterns
No full textThe Tessina landslide is a large, seasonally active slope failure located on the southern slopes of Mt. Teverone, in the Alpago valley of NE Italy, consisting of a complex system that has developed in Tertiary Flysch deposits. The landslide, which first became active in 1960, threatens two villages and is hence subject to detailed monitoring, with high quality data being collected using piezometers, inclinometers, extensometers, and through the use of a highly innovative, automated Electronic Distance Measurement (EDM) system, which surveys the location of a large number of reflector targets once every 6 h. These systems form the basis of a warning system that protects the villages, but they also provide a very valuable insight into the patterns of movement of the landslide. In this paper, analysis is presented of the movement of the landslide, concentrating on the EDM dataset, which provides a remarkable record of surface displacement patterns. It is proposed that four distinct moveme..
The application of SAR data to the interpretation of landslides.
No full textFall AGU, American Geophysical Union Meeting- S. Francisco, CA, US
Axisymmetric oscillations at L-H transitions in JET: M-mode
No full textL to H transition studies at JET have revealed an n = 0, m = 1 magnetic oscillation starting immediately at the L to H transition (called M-mode for brevity). While the magnetic oscillation is present a weak ELM-less H-mode regime is obtained, with a clear increase of density and a weak electron temperature pedestal. It is an intermediate state between L and H-mode. In ICRH heated plasmas or low density NBI plasmas the magnetic mode and the pedestal can remain steady (with small oscillations) for the duration of the heating phase, of order 10 s or more. The axisymmetric magnetic oscillation has period ∼0.5-2 ms, and poloidal mode number m = 1: it looks like a pedestal localised up/down oscillation, although it is clearly a natural oscillation of the plasma, not driven by the position control system. Electron cyclotron emission, interferometry, reflectometry and fast Li beam measurements locate the mode in the pedestal region. Dα, fast infrared camera and Langmuir probe measurements show that the mode modulates heat and particle fluxes to the target. The mode frequency appears to scale with the poloidal Alfvén velocity, and not with sound speed (i.e. it is not a geodesic acoustic mode). A heuristic model is proposed for the frequency scaling of the mode. We discuss the relationship between the M-mode and other related observations near the L-H transition
The interpretation of landslide monitoring data for movement forecasting; an analysis of data from the Tessina landslide in Italy.
No full textRecommended from our members
Mirror Fusion Test Facility magnet system
No full textIn 1979, R.H. Bulmer of Lawrence Livermore National Laboratory (LLNL) discussed a proposed tandem-mirror magnet system for the Mirror Fusion Test Facility (MFTF) at the 8th symposium on Engineering Problems in Fusion Research. Since then, Congress has voted funds for expanding LLNL's MFTF to a tandem-mirror facility (designated MFTF-B). The new facility, scheduled for completion by 1985, will seek to achieve two goals: (1) Energy break-even capability (Q or the ratio of fusion energy to plasma heating energy = 1) of mirror fusion, (2) Engineering feasibility of reactor-scale machines. Briefly stated, 22 superconducting magnets contained in a 11-m-diam by 65-m-long vacuum vessel will confine a fusion plasma fueled by 80 axial streaming-plasma guns and over 40 radial neutral beams. We have already completed a preliminary design of this magnet system
Decreasing resistance in the maternal uterine and peripheral arterial system is apparently unrelated to plasma and urinary levels of nitrite/nitrate and cyclic-guanosinmonophosohate during the course of normal pregnancies
No full textAims: The aim of the presented study was to clarify the relationship between the pulsatility index of the uterine arteries and the maternal cubital artery and peripheral concentrations of the metabolites of nitric oxide (NO) and its second messenger cyclic guanosinmonophophate (cGMP) during the normal course of pregnancy and postpartum. Methods: 49 uncomplicated pregnancies were investigated every 46 weeks until delivery, 29 of them were additionally investigated postpartum. Paralleling each Doppler sonografic investigation maternal blood and urine samples were taken. The measurements of nitrite/ nitrate and cGMP were performed with a colorimetric and radio immuno assay. We demonstrate a significant decrease of the PI of the uterine arteries and of the cubital artery with inverse correlation to advancing gestational age. Results: The concentrations of nitrite/nitrate and cGMP remain stable during gestation and do not correlate to the PI of the uterine and cubital artery. Postpartum a reincrease in the uterine and peripheral resistance can be shown. The concentrations of urinary cGMP and nitrite/ nitrate as well as plasma cGMP remain unchanged, whereas plasma nitrite/nitrate decreases postpartum. Conclusions: The status of NO biosyntheses in normal pregnancy remains controversial. We hypothesize further systemically acting mediators which contribute to the decreasing vascular resistance
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