Relevant bibliographies by topics / Velocity variations

Academic literature on the topic 'Velocity variations'

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Published: 10 March 2023

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Journal articles on the topic "Velocity variations"

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Wang, A., D. Leparoux, O. Abraham, and M. Le Feuvre. "Frequency derivative of Rayleigh wave phase velocity for fundamental mode dispersion inversion: parametric study and experimental application." Geophysical Journal International 224, no. 1 (September 4, 2020): 649–68. http://dx.doi.org/10.1093/gji/ggaa417.

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SUMMARY Monitoring the small variations of a medium is increasingly important in subsurface geophysics due to climate change. Classical seismic surface wave dispersion methods are limited to quantitative estimations of these small variations when the variation ratio is smaller than 10 per cent, especially in the case of variations in deep media. Based on these findings, we propose to study the contributions of the Rayleigh wave phase velocity derivative with respect to frequency. More precisely, in the first step of assessing its feasibility, we analyse the effects of the phase velocity derivative on the inversion of the fundamental mode in the simple case of a two-layer model. The behaviour of the phase velocity derivative is first analysed qualitatively: the dispersion curves of phase velocity, group velocity and the phase velocity derivative are calculated theoretically for several series of media with small variations. It is shown that the phase velocity derivatives are more sensitive to variations of a medium. The sensitivity curves are then calculated for the phase velocity, the group velocity and the phase velocity derivative to perform quantitative analyses. Compared to the phase and group velocities, the phase velocity derivative is sensitive to variations of the shallow layer and the deep layer shear wave velocity in the same wavelength (frequency) range. Numerical data are used and processed to obtain dispersion curves to test the feasibility of the phase velocity derivative in the inversion. The inversion results of the phase velocity derivative are compared with those of phase and group velocities and show improved estimations for small variations (variation ratio less than 5 per cent) of deep layer shear wave velocities. The study is focused on laboratory experiments using two reduced-scale resin-epoxy models. The differences of these two-layer models are in the deep layer in which the variation ratio is estimated as 16.4 ± 1.1 per cent for the phase velocity inversion and 17.1 ± 0.3 per cent for the phase velocity derivative. The latter is closer to the reference value 17 per cent, with a smaller error.
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Hatzes, Artie P. "Radial Velocity Variations from Starspots." International Astronomical Union Colloquium 170 (1999): 259–63. http://dx.doi.org/10.1017/s0252921100048648.

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AbstractIn this contribution the radial velocity (RV) variations expected for starspots on solar-type stars are examined. The spot-induced RV amplitude is found to vary linearly with spot filling factor and is less than 1 m−1 for spot sizes comparable to large sunspots and as high as 20 m s−1 for spot filling factors of 1%. Also, for a given spot size the RV amplitude increases linearly with υ sin i. All of these findings confirm the results of Saar & Donahue (1997). It is also shown that two spectral lines with different temperature sensitivity can have different RV amplitudes which may provide a diagnostic for confirming planet detections. The RV variations due to starspots correlate well with the displacement of the line core and centroid and this can be used to correct RV measurements for the effects of cool starspots.
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de Cacqueray, Benoit, Philippe Roux, Michel Campillo, and Stefan Catheline. "Tracking of velocity variations at depth in the presence of surface velocity fluctuations." GEOPHYSICS 78, no. 1 (January 1, 2013): U1—U8. http://dx.doi.org/10.1190/geo2012-0071.1.

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We tested a small-scale experiment that is dedicated to the study of the wave separation algorithm and to the velocity variations monitoring problem itself. It handles the case in which velocity variations at depth are hidden by near-surface velocity fluctuations. Using an acquisition system that combines an array of sources and an array of receivers, coupled with controlled velocity variations, we tested the ability of beam-forming techniques to track velocity variations separately for body waves and surface waves. After wave separation through double beam forming, the arrival time variations of the different waves were measured through the phase difference between the extracted wavelets. Finally, a method was tested to estimate near-surface velocity variations using surface waves or shallow reflection and compute a correction to isolate target velocity variations at depth.
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Zhang, Yu-Shen, and Thorne Lay. "Global surface wave phase velocity variations." Journal of Geophysical Research: Solid Earth 101, B4 (April 10, 1996): 8415–36. http://dx.doi.org/10.1029/96jb00167.

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Andreasen, Jørn-Ole. "Apparent Short-Term Glacier Velocity Variations." Journal of Glaciology 31, no. 107 (1985): 49–53. http://dx.doi.org/10.1017/s0022143000004986.

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AbstractIn connection with a glacier-hydrological project at a sub-polar glacier in West Greenland, short-term glacier velocity variations were measured. Both the horizontal and the vertical velocity components showed distinct diurnal variations. Close examination indicates that these variations are caused by the change in atmospheric refraction during the day, with the vertical component as the most important.
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Moreno, M., J. Torra, and E. Oblak. "Local Variations of the Velocity Ellipsoid." Symposium - International Astronomical Union 169 (1996): 525–26. http://dx.doi.org/10.1017/s0074180900230271.

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We have analyzed the distribution of residual velocities of nearby stars (within 200 pc of the Sun) looking for space variations on the velocity ellipsoid. We used a sample of 1071 main sequence stars of spectral types B, A and F selected from the Hipparcos Input Catalogue [7] with uvbyHβ photometric data. Ages have been calculated following [1]. Six subsamples with 8.07 ≤ log(age) ≤ 9.45 have been considered.
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Andreasen, Jørn-Ole. "Apparent Short-Term Glacier Velocity Variations." Journal of Glaciology 31, no. 107 (1985): 49–53. http://dx.doi.org/10.3189/s0022143000004986.

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AbstractIn connection with a glacier-hydrological project at a sub-polar glacier in West Greenland, short-term glacier velocity variations were measured. Both the horizontal and the vertical velocity components showed distinct diurnal variations. Close examination indicates that these variations are caused by the change in atmospheric refraction during the day, with the vertical component as the most important.
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Chauhan, A., P. Mullins, M. C. Petch, and P. M. Schofield. "Variations in Resting Coronary Flow Velocity." Clinical Science 84, s28 (March 1, 1993): 14P. http://dx.doi.org/10.1042/cs084014p.

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Ranum, Madeline, Carl Foster, Clayton Camic, Glenn Wright, Flavia Guidotti, Jos J. de Koning, Christopher Dodge, and John P. Porcari. "Effect of Running Velocity Variation on the Aerobic Cost of Running." International Journal of Environmental Research and Public Health 18, no. 4 (February 19, 2021): 2025. http://dx.doi.org/10.3390/ijerph18042025.

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The aerobic cost of running (CR), an important determinant of running performance, is usually measured during constant speed running. However, constant speed does not adequately reflect the nature of human locomotion, particularly competitive races, which include stochastic variations in pace. Studies in non-athletic individuals suggest that stochastic variations in running velocity produce little change in CR. This study was designed to evaluate whether variations in running speed influence CR in trained runners. Twenty competitive runners (12 m, VO2max = 73 ± 7 mL/kg; 8f, VO2max = 57 ± 6 mL/kg) ran four 6-minute bouts at an average speed calculated to require ~90% ventilatory threshold (VT) (measured using both v-slope and ventilatory equivalent). Each interval was run with minute-to-minute pace variation around average speed. CR was measured over the last 2 min. The coefficient of variation (CV) of running speed was calculated to quantify pace variations: ±0.0 m∙s−1 (CV = 0%), ±0.04 m∙s−1 (CV = 1.4%), ±0.13 m∙s−1(CV = 4.2%), and ±0.22 m∙s−1(CV = 7%). No differences in CR, HR, or blood lactate (BLa) were found amongst the variations in running pace. Rating of perceived exertion (RPE) was significantly higher only in the 7% CV condition. The results support earlier studies with short term (3s) pace variations, that pace variation within the limits often seen in competitive races did not affect CR when measured at running speeds below VT.
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González, Diego M., Klaus Bataille, Tom Eulenfeld, and Luis E. Franco. "Temporal seismic wave velocity variations at Láscar volcano." Andean Geology 43, no. 2 (May 19, 2016): 240. http://dx.doi.org/10.5027/andgeov43n2-a05.

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We report on the first study using Seismic Wave Interferometry to determine variations of seismic velocities through time, in the vicinity of Láscar volcano in Chile. Seismic Wave Interferometry has been used as a powerful tool to determine spatial and temporal changes of seismic velocities within the Earth. Spatial variations of seismic velocities are related to heterogeneities of material properties, which are expected to occur in a complex structure. However, temporal changes are indicative of dynamic process within the elastic media, and thus, this tool can be used to monitor dynamic processes at volcanic zones. We find consistent variations on three stations close to the volcano, with dv/v of ±0.6%, most likely related to the inflation/deflation process due to fluid movement of magmatic or hydrothermal origin within the volcanic structure. During the observed period of velocity variation, OVDAS reported an increase of volcanic activity evidenced by the increase of the number of long period seismic events, increase of gas emissions and the formation of incandescence above the crater. We suggest that this tool can contribute to the understanding of volcano related dynamic processes, as well as for routine volcano monitoring purposes.
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Dissertations / Theses on the topic "Velocity variations"

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Darling, Samantha. "Velocity Variations of the Kaskawulsh Glacier, Yukon Territory, 2009-2011." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23511.

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Laser altimetry and satellite gravity surveys indicate that the St Elias Icefields are currently losing mass and are among the largest non-polar sea level contributors in the world. However, a poor understanding of glacier dynamics in the region is a major hurdle in evaluating regional variations in ice motion and the relationship between changing surface conditions and ice flux. This study combines in-situ dGPS measurements and advanced Radarsat-2 (RS-2) processing techniques to determine daily and seasonal ice velocities for the Kaskawulsh Glacier from summer 2009 to summer 2011. Three permanent dGPS stations were installed along the centreline of the glacier in 2009, with an additional permanent station on the South Arm in 2010. The Precise Point Positioning (PPP) method is used to process the dGPS data using high accuracy orbital reconstruction. RS-2 imagery was acquired on a 24-day cycle from January to March 2010, and from October to March 2010-2011 in a combination of ultra-fine and fine beam modes. Seasonal velocity regimes are readily identifiable in the dGPS results, with distinct variations in both horizontal velocity and vertical motion. The Spring Regime consists of an annual peak in horizontal velocity that corresponds closely with the onset of the melt season and progresses up-glacier, following the onset of melt at each station. The Summer Regime sees variable horizontal velocity and vertical uplift, superimposed on a long-term decline in motion. The Fall Regime sees a gradual slowing at all stations with little variation in horizontal velocity or vertical position. Rapid but short accelerations lasting up to 10 days were seen in the Winter regimes in both 2010 and 2011, occurring at various times throughout each regime. These events initiated at the Upper Station and progress down-glacier at propagation speeds up to 16,380 m day-1 and were accompanied by vertical uplift lasting for similar periods. Three velocity maps, one from the winter of 2010 and two from the fall/winter of 2011, produced from speckle tracking were validated by comparison with dGPS velocity, surface flow direction, and bedrock areas of zero motion, with an average velocity error of 2.0% and average difference in orientation of 4.3º.
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Unwin, Beverley Victoria. "Arctic ice cap velocity variations revealed using ERS SAR interferometry." Thesis, University College London (University of London), 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287749.

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This thesis will examine the velocity structure of Austfonna, a large ice cap in the Svalbard archipelago. The remoteness of its location had previously hindered detailed observation by traditional methods, but indirect evidence suggested that it had the potential to be dynamically interesting. A recently developed remote sensing technique, SAR interferometry (inSAR), has allowed us to obtain the most detailed map of Austfonna's topography to date, plus unprecedented synoptic measurements of its velocity field. A four year time series of data acquired by the European Remote Sensing satellites ERS-1 and ERS-2 has been used to delineate active and inactive areas of the ice cap, which suggest that past ideas about Austfonna's thermal structure may need to be re-examined. It has also revealed large temporal velocity variations in one of its major drainage basins. These are difficult to classify because intermittent sampling has prevented us from determining their temporal wavelength, and also because globally the database of observed glacier velocity variations is so sparse that the range of possible variable flow scenarios is unknown. The work here demonstrates the huge potential for inSAR in helping to resolve such issues, and in providing an invaluable resource for scientists monitoring the stability of the world's ice fields.
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Smith, Saskia. "Seismic wave phase-velocity variations in the state of Ohio /." Connect to resource, 2010. http://hdl.handle.net/1811/45057.

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Bertrand, Alexandre. "The impact of seawater velocity variations on time-lapse seismic monitoring." Thesis, Heriot-Watt University, 2005. http://hdl.handle.net/10399/274.

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Tziranis, Alexander Konstantinos 1968. "Temperature, heat flux, and velocity measurements in oscillating flows with pressure variations." Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/12790.

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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1992.
Vita.
Includes bibliographical references (leaves 99-101).
by Alexander Konstantinos Tziranis.
M.S.
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Ghaychi, Afrouz Setareh. "Seismic Wave Velocity Variations in Deep Hard Rock Underground Mines by Passive Seismic Tomography." Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/97890.

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Mining engineers are tasked with ensuring that underground mining operations be both safe and efficiently productive. Induced stress in deep mines has a significant role in the stability of the underground mines and hence the safety of the mining workplace because the behavior of the rock mass associated with mining-induced seismicity is poorly-understood. Passive seismic tomography is a tool with which the performance of a rock mass can be monitored in a timely manner. Using the tool of passive seismic tomography, the advance rate of operation and mining designs can be updated considering the induced stress level in the abutting rock. Most of our current understanding of rock mass behavior associated with mining-induced seismicity comes from numerical modeling and a limited set of case studies. Therefore, it is critical to continuously monitor the rock mass performance under induced stress. Underground stress changes directly influence the seismic wave velocity of the rock mass, which can be measured by passive seismic tomography. The precise rock mass seismicity can be modeled based on the data recorded by seismic sensors such as geophones of an in-mine microseismic system. The seismic velocity of rock mass, which refers to the propagated P-wave velocity, varies associated with the occurrence of major seismic events (defined as having a local moment magnitude between 2 to 4). Seismic velocity changes in affected areas can be measured before and after a major seismic event in order to determine the highly stressed zones. This study evaluates the seismic velocity trends associated with five major seismic events with moment magnitude of 1.4 at a deep narrow-vein mine in order to recognize reasonable patterns correlated to induced stress redistribution. This pattern may allow recognizing areas and times which are prone to occurrence of a major seismic event and helpful in taking appropriate actions in order to mitigate the risk such as evacuation of the area in abrupt cases and changing the aggressive mine plans in gradual cases. In other words, the high stress zones can be distinguished at their early stage and correspondingly optimizing the mining practices to prevent progression of high stress zones which can be ended to a rock failure. For this purpose a block cave mine was synthetically modeled and numerically analyzed in order to evaluate the capability of the passive seismic tomography in determining the induced stress changes through seismic velocity measurement in block cave mines. Next the same method is used for a narrow vein mine as a case study to determine the velocity patterns corresponding to each major seismic event.
Doctor of Philosophy
Mining activities unbalance the stress distribution underground, which is called mining induced stress. The stability of the underground mines is jeopardized due to accumulation of induced stress thus it is critical for the safety of the miners to prevent excessive induced stress accumulation. Hence it is important to continuously monitor the rock mass performance under the induced stress which can form cracks or slide along the existing discontinuities in rock mass. Cracking or sliding releases energy as the source of the seismic wave propagation in underground rocks, known as a seismic event. The velocity of seismic wave propagation can be recorded and monitored by installing seismic sensors such as geophones underground. The seismic events are similar to earthquakes but on a much smaller scale. The strength of seismic events is measured on a scale of moment magnitude. The strongest earthquakes in the world are around magnitude 9, most destructive earthquakes are magnitude 7 or higher, and earthquakes below magnitude 5 generally do not cause significant damage. The moment magnitude of mining induced seismic events is typically less than 3. In order to monitor mining induced stress variations, the propagated seismic wave velocity in rock mass is measured by a series of mathematical computations on recorded seismic waves called passive seismic tomography, which is similar to the medical CT-scan machine. Seismic wave velocity is like the velocity of the vibrating particles of rock due to the released energy from a seismic event. This study proposes to investigate trends of seismic velocity variations before and after each seismic event. The areas which are highly stressed have higher seismic velocities compared to the average seismic velocity of the entire area. Therefore, early recognition of highly stressed zones, based on the seismic velocity amount prior the occurrence of major seismic events, will be helpful to apply optimization of mining practices to prevent progression of high stress zones which can be ended to rock failures. For this purpose, time-dependent seismic velocity of a synthetic mine was compared to its stress numerically. Then, the seismic data of a narrow vein mine is evaluated to determine the seismic velocity trends prior to the occurrence of at least five major seismic events as the case study.
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Bastien, Fabienne Anne. "Empirically Interrelating Stellar Chromospheric Activity, Photometric Variability and Radial Velocity Variations to Enhance Planet Discovery." Thesis, Vanderbilt University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3584409.

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H, Purdie. "Intra-annual variations in abaltion and surface velocity on the lower Fox Glacier, South Westland, New Zealand." Thesis, University of Canterbury. Geography, 2005. http://hdl.handle.net/10092/10451.

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Magoba, Moses. "Investigation of the acoustic impedance variations of the upper shallow marine sandstone reservoirs in the Bredasdorp basin, offshore South Africa." University of the Western Cape, 2019. http://hdl.handle.net/11394/7028.

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Philosophiae Doctor - PhD
Investigation of the acoustic impedance variations in the upper shallow marine sandstone reservoirs was extensively studied from 10 selected wells, namely: F-O1, F-O2, E-M4, E-CN1, E-G1, E-W1, F-A10, F-A11, F-A13, and F-L1 in the Bredasdorp Basin, offshore, South Africa. The studied wells were selected randomly across the upper shallow marine interval with the purpose of conducting a regional study to assess the variations in the acoustic impedance across the reservoirs using wireline log and core data. The datasets used in this study were geophysical wireline logs, conventional core analysis, geological well completion reports, core plugs, and core samples. The physical rock properties such as lithology, fluid type, and hydrocarbon bearing zone were identified while different parameters like the volume of clay, porosity, and water saturation were quantitatively estimated. The reservoirs were penetrated at a different depth ranging from a shallow depth of 2442m at well F-L1 to a deeper depth of 4256.7m at well E-CN1. The average volume of clay, average effective porosity from wireline log, and average water saturation ranged from 8.6%- 43%, 9%- 16% and 12%- 68%, respectively. Porosity distribution was fairly equal across the field from east to west except in well F-A10, F-A13, and F-A11 where a much higher porosity was shown with F-A13 showing the highest average value of 16%. Wells E-CN1, E-W1, F-O1, F-L1 and E-G1 had lower porosity with E-CN1 showing the lowest average value of 9%. The acoustic properties of the reservoirs were determined from geophysical wireline logs in order to calculate acoustic impedance and also investigate factors controlling density and acoustic velocities of these sediments. The acoustic impedance proved to be highest on the central to the western side of the field at E-CN1 with an average value of 11832 g/cm3s whereas, well F-A13 reservoir in the eastern side of the field proved to have the lowest average acoustic impedance of 9821 g/cm3s. There was a good linear negative relationship between acoustic impedance and porosity, compressional velocity vs porosity and porosity vs bulk density. A good linear negative relationship between acoustic impedance and porosity was obtained where the reservoir was homogenous, thick sandstone. However, interbedded shale units within the reservoir appeared to hinder a reliable correlation between acoustic impedance and porosity. The cross-plots results showed that porosity was one of the major factors controlling bulk density, compressional velocity (Vp) and acoustic impedance. The Gassmann equation was used for the determination of the effects of fluid substitution on acoustic properties using rock frame properties. Three fluid substitution models (brine, oil, and gas) were determined for pure sandstones and were used to measure the behaviour of the different sandstone saturations. A significant decrease was observed in Vp when the initial water saturation was substituted with a hydrocarbon (oil or gas) in all the wells. The value of density decreased quite visibly in all the wells when the brine (100% water saturation) was substituted with gas or oil. The fluid substitution affected the rock property significantly. The Vp slightly decreases when brine was substituted with water in wells F-A13, F-A10, F-O2, F-O1 F-A11, F-L1, and E-CN1. Wells E-G1, E-W1, and E-M4 contain oil and gas and therefore showed a notable decrease from brine to oil and from oil to gas respectively. Shear velocity (Vs) remained unaffected in all the wells. The acoustic impedance logs showed a decrease when 100% water saturation was replaced with a hydrocarbon (oil or gas) in all the wells. Clay presence significantly affects the behaviour of the acoustic properties of the reservoir rocks as a function of mineral type, volume, and distribution. The presence of glauconite mineral was observed in all the wells. Thirty-two thin sections, XRD and SEM/EDS from eight out of ten wells were studied to investigate lithology, diagenesis and the effect of mineralogy on porosity and acoustic properties (Compressional velocity and bulk density) within the studied reservoir units. Cementation (calcite and quartz), dissolution, compaction, clay mineral authigenesis, and stylolitization were the most significant diagenetic processes affecting porosity, velocity, and density.Well E-CN1 reservoir quality was very poor due to the destruction of intergranular porosity by extensive quartz and illite cementation, and compaction whereas well F-A13 show a highly porous sandstone reservoir with rounded monocrystalline quartz grain and only clusters of elongate to disc-like, authigenic chlorite crystals partly filling a depression within altered detrital grains. Overall, the results show that the porosity, lithology mineralogy, compaction and pore fluid were the major factors causing the acoustic impedance variations in the upper shallow marine sandstone reservoirs.
2021-09-01
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Balise, Michael John. "The relation between surface and basal velocity variations in glacier, with application to the mini-surges of variegated glacier /." Thesis, Connect to this title online; UW restricted, 1988. http://hdl.handle.net/1773/6846.

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Books on the topic "Velocity variations"

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Swain, Eric D. Effects of horizontal velocity variations on ultrasonic velocity measurements in open channels. Tallahassee, Fla: U.S. Dept. of the Interior, U.S. Geological Survey, 1992.

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Swain, Eric D. Effects of horizontal velocity variations on ultrasonic velocity measurements in open channels. Tallahassee, Fla: U.S. Dept. of the Interior, U.S. Geological Survey, 1992.

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Rasmussen, L. A. Surface velocity variations of the lower part of Columbia Glacier, Alaska, 1977-1981. Washington: U.S. G.P.O., 1989.

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Rasmussen, L. A. Surface velocity variations of the lower part of Columbia Glacier, Alaska, 1977-1981. Washington, DC: Dept. of the Interior, 1989.

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Generazio, Edward R. Imaging subtle microstructural variations in ceramics with precision ultrasonic velocity and attenuation measurements. Cleveland, Ohio: National Aeronautics and Space Administration, Lewis Research Center, 1987.

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George C. Marshall Space Flight Center, ed. North Atlantic basin tropical cyclone activity in relation to temperature and decadal-length oscillation patterns. Huntsville], Ala: National Aeronautics and Space Administration, Marshall Space Flight Center, 2009.

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James, VanFossen G., and United States. National Aeronautics and Space Administration., eds. Increased heat transfer to a cylindrical leading edge due to spanwise variations in the freestream velocity. [Washington, D.C.]: National Aeronautics and Space Administration, 1991.

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D, Ashcroft Peter, Remote Sensing Systems (Firm), and United States. National Aeronautics and Space Administration., eds. SSM/I and ECMWF wind vector comparison: Contract NASW-4714. Santa Rosa, CA: The Systems, 1996.

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Jet Propulsion Laboratory (U.S.), ed. 1982-1983 El Niño atlas: Nimbus-7 microwave radiometer data. Pasadena, Calif: National Aeronautics and Space Administration, Jet Propulsion Laboratory, California Institute of Technology, 1987.

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Jet Propulsion Laboratory (U.S.), ed. 1982-1983 El Niño atlas: Nimbus-7 microwave radiometer data. Pasadena, Calif: National Aeronautics and Space Administration, Jet Propulsion Laboratory, California Institute of Technology, 1987.

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Book chapters on the topic "Velocity variations"

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Tuominen, I., and H. Virtanen. "Solar Rotation Variations from Sunspot Group Statistics." In The Internal Solar Angular Velocity, 83–88. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-3903-5_12.

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Moreno, M., J. Torra, and E. Oblak. "Local Variations of the Velocity Ellipsoid." In Unsolved Problems of the Milky Way, 525–26. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-009-1687-6_83.

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Niemela, V. S., R. H. Barbá, and M. M. Shara. "The Radial Velocity Variations of WR46 (WN3p)." In Wolf-Rayet Stars: Binaries, Colliding Winds, Evolution, 245–47. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-0205-6_56.

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Duffy, Thomas S., and Thomas J. Ahrens. "Lateral Variations in Lower Mantle Seismic Velocity." In High-Pressure Research: Application to Earth and Planetary Sciences, 197–205. Washington, D. C.: American Geophysical Union, 2013. http://dx.doi.org/10.1029/gm067p0197.

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Raveendran, A. V., B. N. Ashoka, and N. Kameswara Rao. "Photometric and Radial Velocity Variations of RCrB Near Maximum Light." In Hydrogen Deficient Stars and Related Objects, 191–97. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4744-3_20.

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Edelmann, H., U. Heber, and C. Karl. "Radial Velocity Variations and Metal Abundances of Three Bright SDB Stars." In White Dwarfs, 87–88. Dordrecht: Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-010-0215-8_23.

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Gerth, E. "Short-Periodic Radial Velocity Variations of the B9p Star ET And." In Upper Main Sequence Stars with Anomalous Abundances, 235–38. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4714-6_39.

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Lin, Yu-Pin. "Crustal Velocity Variations in Taiwan Revealed by Active-Source Seismic Observations." In Isotropic and Anisotropic Seismic Tomography Using Active Source and Earthquake Records, 35–59. Singapore: Springer Singapore, 2017. http://dx.doi.org/10.1007/978-981-10-5068-8_3.

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Medina, Ricardo, Jean E. Elkhoury, Joseph P. Morris, Romain Prioul, Jean Desroches, and Russell L. Detwiler. "Flow of concentrated suspensions through fractures: small variations in solid concentration cause significant in-plane velocity variations." In Crustal Permeability, 27–38. Chichester, UK: John Wiley & Sons, Ltd, 2016. http://dx.doi.org/10.1002/9781119166573.ch5.

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Jiménez, A. "Phase differences between irradiance and velocity low degree solar acoustic modes revisited." In The Sun as a Variable Star: Solar and Stellar Irradiance Variations, 319. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-011-0950-5_53.

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Conference papers on the topic "Velocity variations"

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Fried, Jonathan, and Scott MacKay. "Removing distortions caused by water velocity variations: Water velocity determination." In SEG Technical Program Expanded Abstracts 2002. Society of Exploration Geophysicists, 2002. http://dx.doi.org/10.1190/1.1817109.

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Obilo, J. C., E. de Bazelaire, D. Rousset, H. Perroud, and D. Rappin. "Amplitude Spectrum Variations due to Velocity Gradient." In 64th EAGE Conference & Exhibition. European Association of Geoscientists & Engineers, 2002. http://dx.doi.org/10.3997/2214-4609-pdb.5.c031.

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Wombell, Richard. "Water velocity variations in 3D seismic processing." In SEG Technical Program Expanded Abstracts 1996. Society of Exploration Geophysicists, 1996. http://dx.doi.org/10.1190/1.1826447.

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Margrave, Gary F. "Direct Fourier migration for vertical velocity variations." In SEG Technical Program Expanded Abstracts 1998. Society of Exploration Geophysicists, 1998. http://dx.doi.org/10.1190/1.1820256.

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Santos, H. B., T. A. Coimbra, J. Schleicher, and A. Novais. "Remigration-trajectory Time-migration Velocity Analysis in Regions with Strong Velocity Variations." In 77th EAGE Conference and Exhibition 2015. Netherlands: EAGE Publications BV, 2015. http://dx.doi.org/10.3997/2214-4609.201413048.

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Santos*, H. B., T. A. Coimbra, J. Schleicher, and A. Novais. "Remigration-trajectory time-migration velocity analysis in regions with strong velocity variations." In 14th International Congress of the Brazilian Geophysical Society & EXPOGEF, Rio de Janeiro, Brazil, 3-6 August 2015. Brazilian Geophysical Society, 2015. http://dx.doi.org/10.1190/sbgf2015-209.

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Santos*, Henrique B., Tiago A. Coimbra, Joerg Schleicher, and Amélia Novais. "Migration velocity analysis using time-remigration trajectory: regions with strong velocity variations." In SEG Technical Program Expanded Abstracts 2015. Society of Exploration Geophysicists, 2015. http://dx.doi.org/10.1190/segam2015-5932576.1.

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Lacombe, C., J. Schultzen, S. Butt, and D. Lecerf. "Correction for Water Velocity Variations and Tidal Statics." In 68th EAGE Conference and Exhibition incorporating SPE EUROPEC 2006. European Association of Geoscientists & Engineers, 2006. http://dx.doi.org/10.3997/2214-4609.201402385.

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Guerra, Claudio, José Carbonesi, and Gerson Ritter. "Dynamic correction for water-velocity and tidal variations." In 14th International Congress of the Brazilian Geophysical Society & EXPOGEF, Rio de Janeiro, Brazil, 3-6 August 2015. Brazilian Geophysical Society, 2015. http://dx.doi.org/10.1190/sbgf2015-268.

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Cochran, William D., and Artie P. Hatzes. "High-precision measurement of stellar radial velocity variations." In Spectroscopy '90, 4-6 June, Los Cruces, edited by Bernard J. McNamara and Jeremy M. Lerner. SPIE, 1990. http://dx.doi.org/10.1117/12.22107.

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Reports on the topic "Velocity variations"

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Poppeliers, Christian, and Leiph Preston. The Effects of Stochastic Velocity Variations on Estimating Time Dependent Seismic Moment Tensors: Applications to the Blue Mountain Well Perforation Data. Office of Scientific and Technical Information (OSTI), June 2018. http://dx.doi.org/10.2172/1476894.

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Smith, S. Jarrell, David W. Perkey, and Kelsey A. Fall. Cohesive Sediment Field Study : James River, Virginia. U.S. Army Engineer Research and Development Center, August 2021. http://dx.doi.org/10.21079/11681/41640.

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Estuaries trap much of the fine sediment delivered to them by rivers. This phenomenon presents challenges to the US Army Corps of Engineers (USACE) navigation mission, which maintains navigable waterways for waterborne commerce through estuarine regions. The USACE Regional Sediment Management Program and the USACE Norfolk District are conducting a regional sediment transport modeling study to identify cost-effective sediment management schemes in the James River, a tributary estuary of Chesapeake Bay. A key element of the sediment transport modeling study is the definition of cohesive sediment transport processes, such as erosion and settling velocity. This report describes field-based measurements of cohesive sediment erosion and settling velocity conducted in November 2017. The team conducted erosion testing on 15 cores collected throughout the tidal system. Additionally, two anchor stations were occupied to measure tidal variations in vertical distributions of suspended sediment concentration, particle size, and settling velocity. Recommended cohesive sediment transport parameters were developed from the field measurements.
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Tremblay, T., and M. Lamothe. New contributions to the ice-flow chronology in the Boothia-Lancaster ice-stream catchment area, Nunavut. Natural Resources Canada/CMSS/Information Management, 2023. http://dx.doi.org/10.4095/331424.

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Within the Boothia-Lancaster ice stream (BLIS) catchment area, ice-flow patterns were reconstructed based on the synthesis of striation directions and crosscutting relationships, transport patterns of erratic boulders, glacial landforms, cold-based glacial landsystems, and ice-retreat chronology. New ArcticDEM data, high-definition satellite imagery, and multibeam echosounder bathymetric data sets provided increased details on ice-flow indicators. Convergent high-velocity ice flows through the BLIS main axis were major, persistent features in the northeastern Laurentide Ice Sheet through the last glaciation, and this study highlights intensity fluctuations and ice-flow pattern variations that occurred during that time. Highly contrasting glacial geomorphology, notably in the abundance of moraines, reflects marked differences in ice-margin retreat rates and patterns during deglaciation between the western and eastern sides of the BLIS.
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Tremblay, T., and M. Lamothe. New contributions to the ice-flow chronology in the Boothia-Lancaster Ice Stream catchment area. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/331062.

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Within the Boothia-Lancaster Ice Stream (BLIS) catchment area, ice flow patterns were reconstructed based on the synthesis of striation directions and cross-cutting relationships, transport patterns of erratic boulders, glacial landforms, cold-based glacial landsystems, and ice-retreat chronology. New ArcticDEM data, high-definition satellite imagery and multibeam echosounder bathymetric datasets provided increased details on ice flow indicators. Convergent high-velocity ice flows through the BLIS main axis were major, persistent features in the northeastern Laurentide Ice Sheet through the last glaciation, and this study highlights intensity fluctuations and ice flow pattern variations that occurred during that time. Highly contrasting glacial geomorphology, notably in the abundance of moraines, reflects marked differences in ice-margin retreat rates and patterns during deglaciation between the western and eastern sides of the BLIS.
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Ostashev, Vladimir, Michael Muhlestein, and D. Wilson. Extra-wide-angle parabolic equations in motionless and moving media. Engineer Research and Development Center (U.S.), September 2021. http://dx.doi.org/10.21079/11681/42043.

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Wide-angle parabolic equations (WAPEs) play an important role in physics. They are derived by an expansion of a square-root pseudo-differential operator in one-way wave equations, and then solved by finite-difference techniques. In the present paper, a different approach is suggested. The starting point is an extra-wide-angle parabolic equation (EWAPE) valid for small variations of the refractive index of a medium. This equation is written in an integral form, solved by a perturbation technique, and transformed to the spectral domain. The resulting split-step spectral algorithm for the EWAPE accounts for the propagation angles up to 90° with respect to the nominal direction. This EWAPE is also generalized to large variations in the refractive index. It is shown that WAPEs known in the literature are particular cases of the two EWAPEs. This provides an alternative derivation of the WAPEs, enables a better understanding of the underlying physics and ranges of their applicability, and opens an opportunity for innovative algorithms. Sound propagation in both motionless and moving media is considered. The split-step spectral algorithm is particularly useful in the latter case since complicated partial derivatives of the sound pressure and medium velocity reduce to wave vectors (essentially, propagation angles) in the spectral domain.
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Peters, Susan T. Velocity Variation Over Time for NACO Rounds. Fort Belvoir, VA: Defense Technical Information Center, February 1996. http://dx.doi.org/10.21236/ada307046.

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Artley, C. T. Dip-movement processing for depth-variable velocity. [Correction for variation of velocity with depth]. Office of Scientific and Technical Information (OSTI), December 1992. http://dx.doi.org/10.2172/6912912.

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Nishida, Kenji, Tetsuya Kaneko, Yoichi Takahashi, and Koji Aoki. Estimation of Indicated Mean Effective Pressure Using Crankshaft Angular Velocity Variation. Warrendale, PA: SAE International, November 2011. http://dx.doi.org/10.4271/2011-32-0510.

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Larner, K., and J. K. Cohen. Migration error in transversely isotropic media with linear velocity variation in depth. Office of Scientific and Technical Information (OSTI), January 1992. http://dx.doi.org/10.2172/7201810.

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Larner, K., and J. K. Cohen. Migration error in transversely isotropic media with linear velocity variation in depth. Office of Scientific and Technical Information (OSTI), October 1992. http://dx.doi.org/10.2172/10184162.

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