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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

LAUNCH VEHICLE EXHAUST PLASMA / PLUME EFFECTS ON GROUND TELEMETRY RECEPTION, STARS FT-04-1

McWhorter, Mark 10 1900 (has links)
ITC/USA 2006 Conference Proceedings / The Forty-Second Annual International Telemetering Conference and Technical Exhibition / October 23-26, 2006 / Town and Country Resort & Convention Center, San Diego, California / This paper discusses the effect of vehicle exhaust plasma/plume on the ability to receive telemetered data via an S-band RF link. The data presented herein were captured during the launch of the STARS FT-04-1 on February 23, 2006 from Kodiak Launch Center, Kodiak, Alaska using Alaska Aerospace Development Corporation’s (AADC) Range Safety and Telemetry System (RSTS), designed and integrated by Honeywell.
32

LAUNCH VEHICLE EXHAUST PLASMA / PLUME EFFECTS ON GROUND TELEMETRY RECEPTION, STARS IFT-14

McWhorter, Mark 10 1900 (has links)
ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, Nevada / This paper discusses the effect of vehicle exhaust plasma/plume on the ability to receive telemetered data via an S-band RF link. The data discussed herein was captured during the launch of the STARS IFT-14 on February 13, 2005 from Kodiak Launch Center, Kodiak, Alaska using Alaska Aerospace Development Corporation’s (AADC) Range Safety and Telemetry System (RSTS), designed and integrated by Honeywell.
33

ROCKET MOTOR PLUME EFFECTS ON TM SIGNALS - MODEL CORROBORATION

Johnston, Jerry W., LaPoint, Steve 10 1900 (has links)
International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / This paper presents the interim results of an effort to corroborate analytic model predictions of the effects of rocket motor plume on telemetry signal RF propagation. When space is available, telemetry receiving stations are purposely positioned to be outside the region of a rocket motor's plume interaction with the RF path; therefore, little historical data has been available to corroborate model predictions for specific rocket motor types and altitudes. RF signal strength data was collected during the flight of HERA target missile by White Sands Missile Range (WSMR) using a transportable telemetry receiving site specifically positioned to be within the rocket plume region of influence at intermediate altitudes. The collected data was analyzed and compared to an RF plume attenuation model developed for pre-mission predictions. This work was directed by the US Army Kwajalein Atoll (USAKA)/ Kwajalein Missile Range (KMR) Safety Division.
34

LAUNCH VEHICLE EXHAUST PLASMA / PLUME EFFECTS ON GROUND TELEMETRY RECEPTION, QRLV-2

McWhorter, Mark 10 1900 (has links)
International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / This paper discusses the effect of vehicle exhaust plasma/plume on the ability to receive telemetered data via an S-band RF link. The data discussed herein was captured during the launch of the QRLV-2 (Quick Reaction Launch Vehicle) on April 24, 2002 from Kodiak Launch Center, Kodiak, Alaska using Honeywell’s BMRST (Ballistic Missile Range Safety Technology) system.
35

Evolution of the Earth's mantle-crust-atmosphere system from the trace element and isotope geochemistry of the plume-mantle reservoir

Starkey, Natalie January 2009 (has links)
The 62 million year old lava flows of Baffin Island and West Greenland represent the earliest phase of magmatism in the North Atlantic Igneous Province (NAIP). These picritic lavas are characterised by high magnesium contents owing to their high proportion of olivine crystals. The parental magmas for the picrites are likely to have accumulated olivine crystals on their transit through the lithosphere and crust. Debate over the origin of accumulated crystals in the lavas results in uncertainty in the temperature and composition of the parental magmas for the early NAIP. The magnesium-rich olivine crystals (up to Fo93) in the picrites of this study are shown not to have a xenocrystic origin. The samples, therefore, support the inference of high potential temperatures for the Baffin Island-West Greenland magmas, ~200oC above ambient mantle. The picrites of Baffin Island and West Greenland display the highest terrestrial magmatic 3He/4He (up to 50 Ra, where Ra is the atmospheric value 1.39 x 10-6), values that are considerably higher than the highest 3He/4He in contemporary ocean island basalts, which reach a maximum of ~30 Ra. High 3He/4He in Baffin Island and West Greenland are associated with a wide range of incompatible trace element and lithophile radiogenic isotopic compositions, not dissimilar to the range of compositions displayed by lavas at mid-ocean ridges, and overlapping the range displayed by most northern hemisphere ocean island basalts. Crustal contamination modelling in which high-grade Proterozoic crustal basement rocks are mixed with depleted parents cannot account for the compositional trends displayed by the picrites. Major and trace element compositions were determined on melt inclusions in high- 3He/4He picrites that span a wide range of whole-rock incompatible trace element and radiogenic isotopic compositions. The melt inclusions support the findings from the whole-rock study since melt inclusion compositions reflect the composition of their associated whole-rock, with no anomalous compositions present. In addition, there is no evidence for a contribution of a proportion of depleted melts to the source of the relatively enriched whole-rock samples. Therefore, since all melt inclusions were contained within high-3He/4He samples, it is shown that high 3He/4He is a feature of both depleted and relatively enriched melt compositions. The wide range in whole-rock compositions of the Baffin Island and West Greenland picrites represents that of the sub-lithospheric mantle source region and is inconsistent with derivation of the picrites from residues of ancient mantle depletion. The apparent decoupling of helium from trace elements and radiogenic isotopes is hard to reconcile with simple mixing of a high-helium concentration, high-3He/4He reservoir with various depleted and enriched helium-poor mantle reservoirs. It is possible that primordial helium has diffused into a reservoir with a composition similar to that of the convecting upper mantle. However, this must have occurred after the development of existing mantle heterogeneity. The high-3He/4He picrites require the existence of a deep, primordial helium-rich reservoir. Whether this reservoir is present in the upper or deep mantle, or even the core, remains uncertain.
36

Dispersion and mixing of plumes in wall-bounded and isotropic turbulent flows

Nasseri Oskouie, Shahin 26 August 2016 (has links)
The dispersion and mixing of passive scalars released from two concentrated sources into open-channel and homogeneous isotropic turbulent flows are studied using direct numerical simulation (DNS). The simulations are conducted using two fully-parallelized in-house codes developed using the FORTRAN 90/95 programming language. A comparative study has been conducted to investigate the effects of the source separation distance, Reynolds number, relative length scales of the plume and turbulent flow, and source elevation on the dispersion and mixing of two plumes. For both flow configurations, four distinct stages in the downwind development of the cross correlation between the fluctuating concentration fields have been identified which feature zero, destructive and constructive interferences and a complete mixing state. Differences between the exceedance probability of concentrations for the single and total plumes are highlighted and analyzed, and the effects of destructive and constructive interference on the exceedance probabilities for the total plume are used to explain these differences. It is found that the relationship between the third- and fourth-order concentration moments and the second-order concentration moment can be well predicted using a clipped-gamma model. This leads to an interesting conclusion that all the higher-order (third-order and above) moments of the total concentration can be inferred from a knowledge of only the first- and second-order concentration moments of each single plume and of the cross correlation coefficient. From a spectral analysis, it is observed that there exists a range of `leading scales' at which the rate of turbulent mixing of the two plumes becomes the most efficient and the coherency spectrum of the plumes approaches the asymptotic value of unity quicker than at any other scales. / October 2016
37

Meltwater delivery from the tidewater glacier Kronebreen to Kongsfjorden, Svalbard : insights from in-situ and remote-sensing analyses of sediment plumes

Darlington, Eleanor F. January 2015 (has links)
Tidewater glaciers form a significant drainage catchment of glacierised areas, directly transporting meltwater from the terrestrial to the marine environment. Surface melt of glaciers in the Arctic is increasing in response to warmer atmospheric temperatures, whilst tidewater glaciers are also exposed to warmer ocean temperatures, stimulating submarine melt. Increased freshwater discharge not only freshens fjord waters, but also plays a key role in glacimarine sedimentary processes, transporting sediment to glacial fjords. Despite this, the temporal evolution of meltwater production, storage and release from tidewater glacier systems at seasonal and interannual time scales is poorly understood. This leaves large uncertainties in the predictions for future sea level rise, ocean circulation and the impacts on the marine ecosystem. This study focuses on Kronebreen, a tidewater glacier which flows into the head of Kongsfjorden, north west Svalbard. Surface melt produces freshwater runoff, which is discharged from the grounding line as a buoyant, sediment laden plume, which spreads laterally across the surface water. This supraglacial melt is the dominant freshwater source, contributing an order of magnitude more freshwater to Kongsfjorden, than direct submarine melting of the ice face. Calibration of MODIS band 1 satellite imagery with in situ measurements of Total Suspended Solids and spectral reflectance, provides a method to quantify meltwater and sediment discharge. Plume extent has been determined for each cloud free day, from June to September, 2002 - 2013. Analysis of plume extent with atmospheric temperature and modeled surface runoff, gives a source to sea insight to meltwater production, storage and discharge. The extent of the plume changes in response to meltwater; larger plumes form when discharge increases. These results reveal that meltwater discharge into Kongsfjorden lags atmospheric temperature, the primary driver of meltwater production, by over a week during June and July. This is reduced to only 1 - 2 days in August and September, indicating a decline in meltwater storage as the ablation season progresses, and the development of more efficient glacial drainage. Sediment plumes respond to meltwater production, making them a valuable tool for quantifying meltwater discharge from a tidewater glacier. Insights to glacier hydrology can also be obtained when surface processes are also considered. This furthers the understanding of tidewater glacier hydrology, which is valuable for improving the accuracy of sea level rise predictions.
38

Water Quality Study and Plume Behavior Modeling for Lake Pontchartrain at the Mouth of the Tchefuncte River

Leal Castellano, Jeimmy C. 08 May 2004 (has links)
Over the last several decades, the Lake Pontchartrain Basin has been impacted by the presence of high levels of Fecal Coliform bacteria following periods of rainfall. This is a potential problem for recreational uses of the area. In 2003 a field sampling study was initiated in the north shore area of the Lake at the mouth of the Tchefuncte River. The objectives were to determine the water quality in the area and to simulate the plume patterns from the Tchefuncte River. Twenty eight stations at the mouth of the Tchefuncte River, and a station at the Madisonville Bridge were selected for study on the basis of proximity to the mouth of the River. Fecal coliform counts were found to be “wet” weather-dependent at the mouth of the River and unsuitable for primary contact recreation for at least two to three days following a rain event. A 3-D finite volume hydrodynamics model (A coupled Hydrodynamical-Ecological Model for Regional and Shelf Seas – COHERENS) and the TECPLOT™ equation feature were used for the prediction of contaminant plumes from the Tchefuncte River into the Lake Pontchartrain. The field data were used to validate the model. The upper limits predicted by the model and those measured in the field were in good agreement. The model used river flow and tidal forcing without wind shear. The model verified that that the wet weather effect lasted for two to three-day after a high storm water discharges at the mouth of the river.
39

Qualitative Study of the Effect of a Compartment Enclosure on Fire Plume Entrainment

Anderson, Scott Kenneth 10 February 2005 (has links)
Zone Models are a widely used tool in fire protection engineering to predict how fires will develop in compartments. Zone models use entrainment algorithms for plumes in the open and the effect of enclosures on the entrainment is currently unclear. This work was a systematic study of six global parameters that effect flame height and the enclosure effect on fire plume entrainment.
40

The detection threshold for odor plume tracking in the smooth dogfish, Mustelus canis.

Jennings, Ashley Robina 12 March 2016 (has links)
The survival of Elasmobranch fishes (sharks, skates and rays) depends critically on their ability to sense odor cues. The outstanding question of detection thresholds to food odors in the shark is investigated in this study. The tracking behavior of Mustelus canis (the smooth dogfish) was analyzed using a binary choice flume designed specifically for testing odor preferences of aquatic animals. To determine threshold, odor was serially diluted until no tracking responses were observed. Sharks spent significantly more time in the odor side of the flume, regardless of their individual side bias, until the "squid juice" was diluted several orders of magnitude. For the whole flume the two greatest dilutions (10-4-10-5 at the odor source) did not cause significant choice and for the upstream flume half, all but the greatest dilution (10-5 at the odor source) caused significant odor side preference. To interpret these results fully we need to consider the structure of odor plumes and the function of the sharks' olfactory responses. Nonetheless, assuming that M. canis represent sharks in general, these findings demonstrate that their extraordinary sensitivity to food attractants may indicate aspects still unknown about life history of elasmobranch fishes including the ranges that benthic elasmobranchs are capable of traveling to feed.

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