In-Situ Uniaxial Compression Tests of Level Ice: Part II — Ice Strength Spatial Distribution

2006 ◽  
Author(s):  
Svetlana Shafrova ◽  
Per Olav Moslet
Keyword(s):  
Spatial Distribution ◽  
Field Tests ◽  
Ice Cover ◽  
Strength Distribution ◽  
Test Area ◽  
Compression Tests ◽  
Level Ice ◽  
Ice Strength ◽  
Strength Variability

Part I of this paper describes in-situ field tests of ice strength estimation in relation to the different length scales. Part II deals with the spatial heterogeneity of the ice strength in landfast level ice for the different tests areas. The paper presents a statistical analysis of the ice strength distribution for a Point-area, for a line and for an area in the ice cover. The ice strength distribution for a Point-area varied seasonally. It was estimated in terms of the coefficient of variation about 24.9% at the end of the season. For the coldest months the ice strength variability was around 40%. For the test area the strength spatial variability for the ice samples from the certain ice depth below the ice cover surface was about 19.4% for warm ice and 35.8% for cold ice. The ice strength heterogeneity for a line was determined of 14.4% in case of warm ice.

In-Situ Uniaxial Compression Tests of Level Ice: Part I — Ice Strength Variability Versus Length Scale

2006 ◽  
Author(s):  
Svetlana Shafrova ◽  
Per Olav Moslet
Keyword(s):  
Uniaxial Compression ◽  
Ice Cores ◽  
Length Scale ◽  
Horizontal Distance ◽  
Compression Tests ◽  
Strength Determination ◽  
Level Ice ◽  
Ice Strength ◽  
Strength Variability

Field programs of the ice strength determination through the uniaxial compression tests were carried out on the landfast level ice both in the Van Mijenfjorden and in the Adventfjorden on Svalbard, Norway in 2004 and 2005. The ice strength was examined in relation to the different length scales. The step (horizontal distance) between the ice samples was continuously reduced in order to find out how the ice strength variability develops. The spatial variation of the physical properties of the ice such as temperature, salinity, density has been measured. The typical ice strength variability for the areas larger than 40 m2 is found about 20–30 % for the vertical ice cores of the certain depth from the ice cover surface. For the horizontal ones it is slightly less about 10–20 %.

Ultrastructural analysis of the spatial distribution of MRNA

1992 ◽  
Vol 50 (1) ◽  
pp. 552-553
Author(s):  
Gary Bassell ◽  
Robert H. Singer
Keyword(s):  
Electron Microscopy ◽  
Spatial Distribution ◽  
In Situ Hybridization ◽  
High Resolution ◽  
Nucleic Acids ◽  
Colloidal Gold ◽  
Dna Probe ◽  
Nucleotide Analogs ◽  
Gold Particles

We have been investigating the spatial distribution of nucleic acids intracellularly using in situ hybridization. The use of non-isotopic nucleotide analogs incorporated into the DNA probe allows the detection of the probe at its site of hybridization within the cell. This approach therefore is compatible with the high resolution available by electron microscopy. Biotinated or digoxigenated probe can be detected by antibodies conjugated to colloidal gold. Because mRNA serves as a template for the probe fragments, the colloidal gold particles are detected as arrays which allow it to be unequivocally distinguished from background.

scholarly journals Hot Workability of 300M Steel Investigated by In Situ and Ex Situ Compression Tests

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 880 ◽  
Author(s):  
Rongchuang Chen ◽  
Haifeng Xiao ◽  
Min Wang ◽  
Jianjun Li
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Hot Working ◽  
Ex Situ ◽  
Lower Strain Rate ◽  
Hot Workability ◽  
Compression Tests ◽  
300M Steel ◽  
Lower Strain

In this work, hot compression experiments of 300M steel were performed at 900–1150 °C and 0.01–10 s−1. The relation of flow stress and microstructure evolution was analyzed. The intriguing finding was that at a lower strain rate (0.01 s−1), the flow stress curves were single-peaked, while at a higher strain rate (10 s−1), no peak occurred. Metallographic observation results revealed the phenomenon was because dynamic recrystallization was more complete at a lower strain rate. In situ compression tests were carried out to compare with the results by ex situ compression tests. Hot working maps representing the influences of strains, strain rates, and temperatures were established. It was found that the power dissipation coefficient was not only related to the recrystallized grain size but was also related to the volume fraction of recrystallized grains. The optimal hot working parameters were suggested. This work provides comprehensive understanding of the hot workability of 300M steel in thermal compression.

scholarly journals Underwater Holographic Sensor for Plankton Studies In Situ Including Accompanying Measurements

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4863
Author(s):  
Victor Dyomin ◽  
Alexandra Davydova ◽  
Igor Polovtsev ◽  
Alexey Olshukov ◽  
Nikolay Kirillov ◽  
...  
Keyword(s):  
World Ocean ◽  
Field Tests ◽  
Field Measurements ◽  
Measuring Systems ◽  
Water Turbidity ◽  
Background Data ◽  
Average Size ◽  
Size Dispersion

The paper presents an underwater holographic sensor to study marine particles—a miniDHC digital holographic camera, which may be used as part of a hydrobiological probe for accompanying (background) measurements. The results of field measurements of plankton are given and interpreted, their verification is performed. Errors of measurements and classification of plankton particles are estimated. MiniDHC allows measurement of the following set of background data, which is confirmed by field tests: plankton concentration, average size and size dispersion of individuals, particle size distribution, including on major taxa, as well as water turbidity and suspension statistics. Version of constructing measuring systems based on modern carriers of operational oceanography for the purpose of ecological diagnostics of the world ocean using autochthonous plankton are discussed. The results of field measurements of plankton using miniDHC as part of a hydrobiological probe are presented and interpreted, and their verification is carried out. The results of comparing the data on the concentration of individual taxa obtained using miniDHC with the data obtained by the traditional method using plankton catching with a net showed a difference of no more than 23%. The article also contains recommendations for expanding the potential of miniDHC, its purpose indicators, and improving metrological characteristics.

PRESSURE AMPLITUDES OF SEISMIC SIGNALS IN OFFSHORE LOUISIANA

Geophysics ◽  
1977 ◽  
Vol 42 (1) ◽  
pp. 3-16
Author(s):  
M. E. Arnold
Keyword(s):  
Field Tests ◽  
Signal Amplitude ◽  
Test Area ◽  
Seismic Signals ◽  
Code Generators ◽  
Single Detector ◽  
First Arrival ◽  
Reflected Signal ◽  
Refracted Waves ◽  
Seismic Lines

Pressure amplitudes were determined for various kinds of seismic signals observed on special test records obtained during field tests conducted along a 14,000-ft seismic lines in Eugene Island Block 184, offshore Louisiana. Vibrators attached to a Seismograph Service Corp. (SSC) boat generated swept‐frequency and monofrequency signals. Signals from detectors on a streamer cable towed by the boat were recorded by an SSC recording system. Signals from a vertical spread of detectors were recorded by a DFS/9000 recorder on the Transco 184 platform centrally located in the test area. Location of the boat was determined by analysis of time relations of signals from responders located at established positions some distance from the test area. Clock times from manually referenced timing code generators were recorded by both the SSC and DFS recorders to permit synchronization between separately recorded signals. The signals analyzed were separated into three classes: [Formula: see text] includes direct and refracted waves; [Formula: see text] consists of primary reflections; and [Formula: see text] includes signals diffracted from scatterers. The average level of first‐arrival signal [Formula: see text] and reflected signal [Formula: see text] for frequency sets 25, 40, 42.2, 50, and 70.4 Hz in the range of 1414 and 2143 ft, which encompasses streamer cable single‐detector groups, is 337 and 29.6 microbars, respectively. The amplitude of signals [Formula: see text], believed to be diffracted from the contact between key reflectors and a salt dome, ranges from 13 to 20 microbars and is 10 to 100 times the amplitudes of towing and ambient noise, respectively. The observed decay of first‐arrival signal amplitude is approximately proportional to the square root of range distance, or about 2 dB/1000 ft. The observed decay of reflected signal amplitude with range distance is approximately 1 dB/1000 ft.

scholarly journals Characterization of interferences to in situ observations of <i>δ</i><sup>13</sup>CH<sub>4</sub> and C<sub>2</sub>H<sub>6</sub> when using a cavity ring-down spectrometer at industrial sites

2017 ◽  
Vol 10 (6) ◽  
pp. 2077-2091 ◽  
Author(s):  
Sabina Assan ◽  
Alexia Baudic ◽  
Ali Guemri ◽  
Philippe Ciais ◽  
Valerie Gros ◽  
...  
Keyword(s):  
Near Infrared ◽  
Field Tests ◽  
Isotopic Signature ◽  
Ambient Conditions ◽  
Industrial Sites ◽  
Source Determination ◽  
Infrared Spectral ◽  
The Subject

Abstract. Due to increased demand for an understanding of CH4 emissions from industrial sites, the subject of cross sensitivities caused by absorption from multiple gases on δ13CH4 and C2H6 measured in the near-infrared spectral domain using CRDS has become increasingly important. Extensive laboratory tests are presented here, which characterize these cross sensitivities and propose corrections for the biases they induce. We found methane isotopic measurements to be subject to interference from elevated C2H6 concentrations resulting in heavier δ13CH4 by +23.5 ‰ per ppm C2H6 ∕ ppm CH4. Measured C2H6 is subject to absorption interference from a number of other trace gases, predominantly H2O (with an average linear sensitivity of 0.9 ppm C2H6 per  % H2O in ambient conditions). Yet, this sensitivity was found to be discontinuous with a strong hysteresis effect and we suggest removing H2O from gas samples prior to analysis. The C2H6 calibration factor was calculated using a GC and measured as 0.5 (confirmed up to 5 ppm C2H6). Field tests at a natural gas compressor station demonstrated that the presence of C2H6 in gas emissions at an average level of 0.3 ppm shifted the isotopic signature by 2.5 ‰, whilst after calibration we find that the average C2H6 : CH4 ratio shifts by +0.06. These results indicate that, when using such a CRDS instrument in conditions of elevated C2H6 for CH4 source determination, it is imperative to account for the biases discussed within this study.

scholarly journals Assessment of the Accuracy of a Multi-Beam LED Scanner Sensor for Measuring Olive Canopies

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4406 ◽  
Author(s):  
Rafael Sola-Guirado ◽  
Sergio Bayano-Tejero ◽  
Antonio Rodríguez-Lizana ◽  
Jesús Gil-Ribes ◽  
Antonio Miranda-Fuentes
Keyword(s):  
Laboratory Test ◽  
Real Time ◽  
Relative Error ◽  
Laser Scanner ◽  
Field Tests ◽  
High Accuracy ◽  
Field Conditions ◽  
Canopy Trees ◽  
Canopy Volume

Canopy characterization has become important when trying to optimize any kind of agricultural operation in high-growing crops, such as olive. Many sensors and techniques have reported satisfactory results in these approaches and in this work a 2D laser scanner was explored for measuring canopy trees in real-time conditions. The sensor was tested in both laboratory and field conditions to check its accuracy, its cone width, and its ability to characterize olive canopies in situ. The sensor was mounted on a mast and tested in laboratory conditions to check: (i) its accuracy at different measurement distances; (ii) its measurement cone width with different reflectivity targets; and (iii) the influence of the target’s density on its accuracy. The field tests involved both isolated and hedgerow orchards, in which the measurements were taken manually and with the sensor. The canopy volume was estimated with a methodology consisting of revolving or extruding the canopy contour. The sensor showed high accuracy in the laboratory test, except for the measurements performed at 1.0 m distance, with 60 mm error (6%). Otherwise, error remained below 20 mm (1% relative error). The cone width depended on the target reflectivity. The accuracy decreased with the target density.

scholarly journals Heat Budget in the Ice Cover of the Southern Okhotsk Sea Derived from In-situ Observations

2000 ◽  
Vol 78 (5) ◽  
pp. 585-596 ◽  
Author(s):  
Takenobu Toyota ◽  
Toshiyuki Kawamura ◽  
Masaaki Wakatsuchi
Keyword(s):  
Heat Budget ◽  
Ice Cover ◽  
Okhotsk Sea ◽  
In Situ Observations
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