scholarly journals High-resolution distributed vertical strain and velocity from repeat borehole logging by optical televiewer: Derwael Ice Rise, Antarctica

2020 ◽  
Vol 66 (258) ◽  
pp. 523-529
Author(s):  
Bryn Hubbard ◽  
Morgane Philippe ◽  
Frank Pattyn ◽  
Reinhard Drews ◽  
Tun Jan Young ◽  
...  
Keyword(s):  
High Resolution ◽  
Strain Rate ◽  
Effective Means ◽  
Borehole Logging ◽  
Vertical Strain ◽  
Direct Measurements ◽  
Spatially Distributed ◽  
Measured Strain ◽  
Different Depths ◽  
Depth Ranges

AbstractDirect measurements of spatially distributed vertical strain within ice masses are scientifically valuable but challenging to acquire. We use manual marker tracking and automatic cross correlation between two repeat optical televiewer (OPTV) images of an ~100 m-long borehole at Derwael Ice Rise (DIR), Antarctica, to reconstruct discretised, vertical strain rate and velocity at millimetre resolution. The resulting profiles decay with depth, from −0.07 a−1 at the surface to ~−0.002 a−1 towards the base in strain and from −1.3 m a−1 at the surface to ~−0.5 m a−1 towards the base in velocity. Both profiles also show substantial local variability. Three coffee-can markers installed at different depths into adjacent boreholes record consistent strain rates and velocities, although averaged over longer depth ranges and subject to greater uncertainty. Measured strain-rate profiles generally compare closely with output from a 2-D ice-flow model, while the former additionally reveal substantial high-resolution variability. We conclude that repeat OPTV borehole logging represents an effective means of measuring distributed vertical strain at millimetre scale, revealing high-resolution variability along the uppermost ~100 m of DIR, Antarctica.

scholarly journals Vertical strain-rate measurements in an arctic ice cap and gerductions freom them

1976 ◽  
Vol 17 (75) ◽  
pp. 3-12 ◽  
Author(s):  
W. S. B. Paterson
Keyword(s):  
Strain Rate ◽  
Accumulation Rate ◽  
Vertical Component ◽  
Contraction Rate ◽  
Devon Island ◽  
Vertical Strain ◽  
The Past ◽  
Ice Cap ◽  
Measured Strain ◽  
Arctic Ice

AbstractClosely spaced measurements of diameter of thermally drilled bore holes reveal a pattern of small variations. These patterns serve to igerntify points on the bore-hole wall; thus the change in length of sections of bore hole can be gertermined as a function of time. This method has been used to measure vertical strain-rate as a function of gerpth in two bore holes near the crest of the Devon Island ice cap. The measured strain-rate, corrected for firn compaction, varies significantly with gerpth. The vertical component of velocity at the surface was gertermined freom the contraction rate of a bore hole that penetrated to the base of the ice. Comparison of this velocity with the present accumulation rate suggests that the ice cap, in the vicinity of the bore hole, is thickening slightly at present. The age of the ice at various gerpths, as calculated freom the measured vertical velocities, is in broad agreement with radio-carbon dates covering the past 6 000 years. This suggests that the flow of the ice cap has not varied significantly over this period, and thus that the present accumulation rate, which is causing thickening, is slightly above the average for the period.

scholarly journals Vertical Strain-rate Measurements in an Arctic Ice Cap and deductions from them

1976 ◽  
Vol 17 (75) ◽  
pp. 3-12 ◽  
Author(s):  
W. S. B. Paterson
Keyword(s):  
Strain Rate ◽  
Accumulation Rate ◽  
Vertical Component ◽  
Contraction Rate ◽  
Devon Island ◽  
Vertical Strain ◽  
The Past ◽  
Ice Cap ◽  
Measured Strain ◽  
Arctic Ice

AbstractClosely spaced measurements of diameter of thermally drilled bore holes reveal a pattern of small variations. These patterns serve to igerntify points on the bore-hole wall; thus the change in length of sections of bore hole can be gertermined as a function of time. This method has been used to measure vertical strain-rate as a function of gerpth in two bore holes near the crest of the Devon Island ice cap. The measured strain-rate, corrected for firn compaction, varies significantly with gerpth. The vertical component of velocity at the surface was gertermined freom the contraction rate of a bore hole that penetrated to the base of the ice. Comparison of this velocity with the present accumulation rate suggests that the ice cap, in the vicinity of the bore hole, is thickening slightly at present. The age of the ice at various gerpths, as calculated freom the measured vertical velocities, is in broad agreement with radio-carbon dates covering the past 6 000 years. This suggests that the flow of the ice cap has not varied significantly over this period, and thus that the present accumulation rate, which is causing thickening, is slightly above the average for the period.

scholarly journals TNO-MACC_II emission inventory; a multi-year (2003–2009) consistent high-resolution European emission inventory for air quality modelling

2014 ◽  
Vol 14 (20) ◽  
pp. 10963-10976 ◽  
Author(s):  
J. J. P. Kuenen ◽  
A. J. H. Visschedijk ◽  
M. Jozwicka ◽  
H. A. C. Denier van der Gon
Keyword(s):  
Particulate Matter ◽  
Air Quality ◽  
High Resolution ◽  
Emission Inventory ◽  
Point Sources ◽  
Air Quality Modelling ◽  
Emission Data ◽  
Data Set ◽  
Spatially Distributed ◽  
Reported Data

Abstract. Emissions to air are reported by countries to EMEP. The emissions data are used for country compliance checking with EU emission ceilings and associated emission reductions. The emissions data are also necessary as input for air quality modelling. The quality of these "official" emissions varies across Europe. As alternative to these official emissions, a spatially explicit high-resolution emission inventory (7 × 7 km) for UNECE-Europe for all years between 2003 and 2009 for the main air pollutants was made. The primary goal was to supply air quality modellers with the input they need. The inventory was constructed by using the reported emission national totals by sector where the quality is sufficient. The reported data were analysed by sector in detail, and completed with alternative emission estimates as needed. This resulted in a complete emission inventory for all countries. For particulate matter, for each source emissions have been split in coarse and fine particulate matter, and further disaggregated to EC, OC, SO4, Na and other minerals using fractions based on the literature. Doing this at the most detailed sectoral level in the database implies that a consistent set was obtained across Europe. This allows better comparisons with observational data which can, through feedback, help to further identify uncertain sources and/or support emission inventory improvements for this highly uncertain pollutant. The resulting emission data set was spatially distributed consistently across all countries by using proxy parameters. Point sources were spatially distributed using the specific location of the point source. The spatial distribution for the point sources was made year-specific. The TNO-MACC_II is an update of the TNO-MACC emission data set. Major updates included the time extension towards 2009, use of the latest available reported data (including updates and corrections made until early 2012) and updates in distribution maps.

Strain accumulation in Owens Valley, California, 1974 to 1988

1995 ◽  
Vol 85 (1) ◽  
pp. 151-158
Author(s):  
J. C. Savage ◽  
M. Lisowski
Keyword(s):  
Strain Rate ◽  
Coordinate System ◽  
Strain Accumulation ◽  
Lateral Deformation ◽  
Lateral Shear ◽  
Owens Valley ◽  
Conventional Model ◽  
Measured Strain ◽  
Standard Deviations ◽  
Buried Fault

Abstract Strain accumulation observed over the 1974 to 1988 interval in a 25 by 100 km aperture trilateration network spanning Owens Valley is adequately described by a strain rate that is uniform in space and time. The tensor strain-rate components referred to a coordinate system with the 2 axis directed N18°W (parallel to the trend of the valley) and the 1 axis N72°E are ∈˙11′ = 0.042 ± 0.014 μstrain/yr, ∈˙12′ = -0.058 ± 0.007 μstrain/yr, and ∈˙22′ = 0.002 ± 0.014 μstrain/yr; quoted uncertainties are standard deviations and extension is reckoned positive. Across the 25-km breadth of the network, this amounts to 1.0 ± 0.3 mm/yr extension normal to the axis of the valley, 2.9 ± 0.4 mm/yr right-lateral shear across the axis, and no extension parallel to the axis. If the measured strain accumulation is attributed to slip on the deeper section of the Owens Valley fault with the uppermost 10 km of the fault locked, the observed right-lateral deformation would imply about 7 mm/yr right-lateral slip on the buried fault, much greater than the geologic estimate of 2 ± 0.5 mm/yr right-lateral secular slip (Beanland and Clark, 1994). Nor is the observed uplift profile across the valley consistent with continuing normal slip on just the deep segment of the Owens Valley fault; normal slip at depth on the Sierra frontal fault also seems to be required. The observed deformation across Owens Valley apparently implies processes more complicated than those represented by the conventional model of strain accumulation along a throughgoing fault.

scholarly journals Feasability of Diaphragmatic Speckle Tracking In Intensive Care Units

2021 ◽  
Author(s):  
Michael Poette ◽  
Laure Crognier ◽  
Fanny Vardon-Bounes ◽  
Stéphanie Ruiz ◽  
Bernard Georges ◽  
...  
Keyword(s):  
Intensive Care ◽  
Strain Rate ◽  
Intensive Care Units ◽  
Strongly Correlated ◽  
Diaphragmatic Dysfunction ◽  
Good Reliability ◽  
Diaphragmatic Function ◽  
Strain And Strain Rate ◽  
Measured Strain ◽  
The Right

Abstract Background: Diaphragmatic dysfunction is a common condition in intensive care units (ICU). Its presence correlates with prolonged weaning from mechanical ventilation and mortality. Diaphragmatic excursion (EXdi) and thickening fraction (TFdi) are the 2 main measures currently described in diaphragmatic ultrasound, but each has its limitations. Strain and strain rate are already used cardiac sonography and could be of interest in the assessment of diaphragmatic function in ICU. The aim of this work was to evaluate the feasibility of diaphragmatic strain and strain rate in ICU and to describe their distribution, reproducibility and agreement with existing parameters. Methods: All patients who underwent a T-tube weaning test were prospectively included. Ultrasound loops were recorded on each side of the patient during the last 30 minutes of the weaning test. Two operators measured strain, strain rate, EXdi, and TFdi blind to each other in post-treatment analysis. Results: Thirty patients were analyzed. The median values for strain and strain rate were -6.74% and -0.23.s-1 on the left side and -8.17% and -0.22.s-1 on the right side. Concerning strain and strain rate, intra-class coefficients showed systematically a very good reliability between operators. Conclusion: Diaphragmatic strain and strain rate measurements appeared feasible in an ICU environment and seemed reproducible and not strongly correlated with EXdi and TFdi. An improvement of the analysis software is needed to improve the ease of interpretation. The interest of these parameters in clinical practice should be explored in forthcoming studies.

scholarly journals Solar-like oscillations in subgiant and red-giant stars: mixed modes

2013 ◽  
Vol 9 (S301) ◽  
pp. 325-331 ◽  
Author(s):  
S. Hekker ◽  
A. Mazumdar
Keyword(s):  
High Resolution ◽  
Outer Part ◽  
Space Missions ◽  
Giant Stars ◽  
Internal Structures ◽  
Different Depths ◽  
Mixed Modes ◽  
Red Giant Stars ◽  
Red Giant

AbstractThanks to significant improvements in high-resolution spectrographs and the launch of dedicated space missions MOST, CoRoT and Kepler, the number of subgiants and red-giant stars with detected oscillations has increased significantly over the last decade. The amount of detail that can now be resolved in the oscillation patterns does allow for in-depth investigations of the internal structures of these stars. One phenomenon that plays an important role in such studies are mixed modes. These are modes that carry information of the inner radiative region as well as from the convective outer part of the star allowing to probe different depths of the stars.Here, we describe mixed modes and highlight some recent results obtained using mixed modes observed in subgiants and red-giant stars.

Type II Dislocation Loops and their Effect on Strain in Ion Implanted Silicon as Studied by High Resolution X-ray Diffraction

1995 ◽  
Vol 378 ◽  
Author(s):  
R. H. Thompson ◽  
V. Krishnamoorthy ◽  
J. Liu ◽  
K. S. Jones
Keyword(s):  
High Resolution ◽  
Type Ii ◽  
Dislocation Loops ◽  
X Ray Diffraction ◽  
Empirical Constant ◽  
Plan View ◽  
X Ray ◽  
Transmission Electron ◽  
Measured Strain ◽  
P Type

AbstractP-type (100) silicon wafers were implanted with 28Si+ ions at an energy of 50 keV and to doses of 1 × 1015, 5 × 1015 and 1 × 1016 cm−2, respectively, and annealed in a N2 ambient at temperatures ranging from 700°C to 1000°C for times ranging from 15 minutes to 16 hours. The resulting microstructure consisted of varying distributions of Type II end of range dislocation loops. The size distribution of these loops was quantified using plan-view transmission electron microscopy and the strain arising from these loops was investigated using high resolution x-ray diffraction. The measured strain values were found to be constant in the loop coarsening regime wherein the number of atoms bound by the loops remained a constant. Therefore, an empirical constant of 7.7 × 10−12 interstitial/ppm of strain was evaluated to relate the number of interstitials bound by these dislocation loops and the strain. This value was used successfully in estimating the number of interstitials bound by loops at the various doses studied provided the annealing conditions were such that the loop microstructure was in the coarsening or dissolution regime.

scholarly journals Estimation of the advection effects induced by surface heterogeneities in the surface energy budget

2016 ◽  
Author(s):  
J. Cuxart ◽  
B. Wrenger ◽  
D. Martínez-Villagrasa ◽  
J. Reuder ◽  
M.O. Jonassen ◽  
...  
Keyword(s):  
High Resolution ◽  
Surface Energy ◽  
Energy Budget ◽  
Surface Energy Budget ◽  
Temperature Fields ◽  
Direct Measurements ◽  
Advection Term ◽  
Thermal Cameras ◽  
Remotely Piloted Aircraft ◽  
Order Of Magnitude

Abstract. The effect of terrain heterogeneities in one-point measurements is a continuous subject of discussion. Here we focus on the order of magnitude of the advection term in the equation of the temperature as generated by documented terrain heterogeneities and we estimate its importance as a term in the surface energy budget (SEB). The heterogeneities are estimated from satellite and model fields for scales near 1 kilometer or broader, while the smaller scales are estimated through direct measurements with remotely-piloted aircraft, thermal cameras and also by high-resolution modeling. The variability of the surface temperature fields is not found to decrease clearly with increasing resolution, and consequently the advection term becomes more important as the scales become finer. The advection term provides non-significant values to the SEB at scales larger than few kilometers. On the contrary, surface heterogeneities at the meter scale yield large values of the advection, which are probably only significant in the first centimeters above the ground. The motions that seem to contribute significantly to the advection term in the SEB equation in our case are roughly those around the hectometer scales.

Depth Distribution of the Carotenoid Pigments and Lipids of Some Oceanic Animals 1. Mixed Zooplankton, Copepods and Euphausiids

1972 ◽  
Vol 52 (1) ◽  
pp. 179-189 ◽  
Author(s):  
Peter J. Herring
Keyword(s):  
Lipid Content ◽  
Depth Distribution ◽  
Carotenoid Pigments ◽  
Carotenoid Pigment ◽  
Protective Coloration ◽  
Close Relationship ◽  
Different Depths ◽  
Pigment Concentrations ◽  
Depth Ranges ◽  
Related Increase

Analysis of the carotenoid pigment and lipid concentrations of groups of the smaller zooplankton organisms from different depths has suggested a midwater maximum for carotenoid concentrations and a slight depth-related increase in lipid content. Similar analysis of seventeen species of euphausiid has not indicated similar trends, but has shown a close relationship between size and pigment content in all species other than those ofStylocheiron,which have significantly lower pigment concentrations. Comparisons of the data of Fisher, Kon & Thompson (1964) on the pigment and lipid concentrations of copepods with the known depth ranges of the various species have suggested a midwater maximum in pigment concentrations, but no consistent trends in the lipid concentrations. A midwater pigment peak is explicable in terms of pigment accessibility and requirement for protective coloration, and the significance of the pigments is discussed.

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