• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 287
  • 60
  • 60
  • 60
  • 60
  • 60
  • 59
  • 8
  • 3
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 415
  • 415
  • 138
  • 116
  • 106
  • 80
  • 80
  • 80
  • 80
  • 80
  • 80
  • 80
  • 60
  • 53
  • 49
  • 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.
41

A DIAGNOSTIC MODEL OF CONTINENTAL SHELF CIRCULATION

Unknown Date (has links)
Source: Dissertation Abstracts International, Volume: 38-04, Section: B, page: 1629. / Thesis (Ph.D.)--The Florida State University, 1976.
42

THE GEOCHEMISTRY OF MERCURY IN THREE ESTUARIES FROM THE GULF OF MEXICO

Unknown Date (has links)
Source: Dissertation Abstracts International, Volume: 34-04, Section: B, page: 1657. / Thesis (Ph.D.)--The Florida State University, 1973.
43

THE EFFECTS OF HYDROSTATIC PRESSURE AND TEMPERATURE ON UCA PUGILATOR (BOSC)

Unknown Date (has links)
Source: Dissertation Abstracts International, Volume: 34-06, Section: B, page: 2810. / Thesis (Ph.D.)--The Florida State University, 1973.
44

TASMAN BASIN SEDIMENTATION: PATTERNS AND PROCESSES

Unknown Date (has links)
Source: Dissertation Abstracts International, Volume: 33-05, Section: B, page: 2238. / Thesis (Ph.D.)--The Florida State University, 1972.
45

FLORIDA CURRENT SPIN-OFF EDDIES

Unknown Date (has links)
Source: Dissertation Abstracts International, Volume: 34-02, Section: B, page: 0787. / Thesis (Ph.D.)--The Florida State University, 1973.
46

CATION EXCHANGE CAPACITY AND EXCHANGEABLE METALS IN A SOUTH FLORIDA WATERSHED

Unknown Date (has links)
Source: Dissertation Abstracts International, Volume: 33-11, Section: B, page: 5420. / Thesis (Ph.D.)--The Florida State University, 1973.
47

THE COOLING AND SINKING OF WARM-CORE RINGS (GULF STREAM)

Unknown Date (has links)
Intense cooling of a warm-core ring can cause the ring to sink under the surrounding fluids. A simple model of this process in a two and one-half layer (two active and one passive layer) ocean consisting of an inviscid Boussinesq fluid on an f-plane is presented. The model assumes that the cooling is limited to just the ring and occurs in such a way as to maintain a uniform density throughout the ring. This special cooling allows the results for various ring densities to be connected through the conservation of potential vorticity. The analytic solution that is derived for this model is examined to establish the physical processes accompanying the cooling and sinking of a ring. / Results show that warm-core rings can sink in a matter of days when exposed to typical cold air outbreaks of 500 to 1000 W m('-2). The model predicts that when the ring sinks it is overwashed completely, but this overwashing layer is very thin near the center of the ring. Thus the overwashing fluid would slow (but not eliminate) the cooling of the ring. Further analysis of the system assuming that the ring continues to be cooled after sinking shows that the overwashing fluids spiral in towards the center of the ring. These spiral trajectories steepen as the cooling rate increases, achieving spiral angles approaching those observed in Gulf Stream rings for cooling rates of about 1000 W m('-2). It is proposed that this mechanism can lead to the formation of streamers when one portion of the overwashing fluid has been passively marked with a visible tracer such as temperature or chlorophyll. / It is shown that the fluid that initially overwashes the ring originates under the ring, and not from outside the ring. When the ring sinks, this fluid is pushed out to the edge of the ring and spun up in the process. The theory further provides a mechanism for the entrainment of shelf-water organisms that are observed in warm-core rings. / Source: Dissertation Abstracts International, Volume: 48-03, Section: B, page: 0688. / Thesis (Ph.D.)--The Florida State University, 1987.
48

A NUMERICAL STUDY ON THE INFLUENCE OF THE MID-ATLANTIC RIDGE ON NON-LINEAR BAROTROPIC AND FIRST MODE BAROCLINIC ROSSBY WAVES GENERATED BY SEASONAL WINDS

Unknown Date (has links)
A numerical model simulation investigates the influence of the mid-Atlantic ridge on non-linear barotropic and first-mode baroclinic Rossby waves generated by seasonal wind fluctuations. The north Atlantic is simulated by a square-box, two-layer quasi-geostrophic model. The bottom topography is ridge-like and compromises the QG approximation and the actual shape of the ridge. Sponge layers protect all boundaries except the eastern one from wave reflexion. The model is forced by a purely fluctuating wind stress curl derived from the most significant EOF's of the FGGE winds. A flat bottom and a ridge experiment are compared. The topography is an important source of barotropic variability for the eastern basin. The topographic Rossby waves generated over the ridge, either by wave reflexion or by direct wind forcing, account for at least 50% of the barotropic variability of that basin. Their frequencies range from 0.01 to 0.05 cpd. / In both experiments the eastern boundary is an important source of annual-period baroclinic Rossby waves. Wavetrains having a wavelength of about 1060 km and a westward phase speed around 3.4 cm sec('-1) propagate energy westward at 3 cm sec('-1). In the flat bottom experiment a source of directly wind-forced baroclinic waves of annual period is found in the middle of the basin. Their amplitude is smaller and they have a noticeable northward phase propagation resulting in a southward group velocity component. The topography blocks the waves coming from the eastern boundary but generates new wavetrains whose phase vector is almost normal to the ridge crest. Those waves propagate energy mostly westward at 2.9 cm sec('-1). The northern waves are out of phase with the southern ones because of the structure of the dominant wind pattern over the ridge region where they are generated. All waves have a small group velocity component in the meridional direction. It is northward (at 0.34 cm sec('-1)) for the northern waves and southward (at 0.32 cm sec('-1)) for the southern waves. / Source: Dissertation Abstracts International, Volume: 47-12, Section: B, page: 4811. / Thesis (Ph.D.)--The Florida State University, 1986.
49

RELEASE AND TRANSPORT OF RADIUM DURING WEATHERING IN CENTRAL AND NORTH FLORIDA

Unknown Date (has links)
Samples of fresh and weathered Florida phosphate rock were analyzed for several uranium decay-series radionuclides. In bulk samples, almost all radionuclides display higher activities in weathered samples compared to fresh material. ('230)Th is normally in isotopic equilibrium with ('234)U in fresh material but is often depleted and occasionally enriched in highly weathered samples. ('226)Ra is close to equilibrium with its parent ('230)Th in most samples. ('210)Pb/('226)Ra activity ratios were less than 1.00, as expected, due to radon leakage. Less than unity activity ratios of ('210)Po/('210)Pb in a few weathered samples indicates a preferential release of ('210)Po under some conditions. / Highly weathered samples contain the most significant portion of their activity within the finest size fraction, while radionuclide activity in fresh samples tends to follow the predominant size of the phosphate particles. The finest size material of nearly all weathered samples shows a significant depletion of ('226)Ra relative to ('238)U, while fresher samples show a small excess ('226)Ra activity. Radionuclide concentrations are governed by 2 processes which occur during intense weathering of phosphate rock: (1) increased surface area with enhanced adsorption and (2) transformation of phosphate pellets into more CARFAP-pure "pebble" phases. / Based on over 2 years of measurements, the mean concentration of dissolved ('226)Ra in the Suwannee River is 26 dpm 100L('-1), 2-4 times higher than most other world's rivers. Radium in the Suwannee River appears to be controlled by two processes: (1) relative mixing of water from surface drainage (low radium); and (2) interaction between soluble radium and particulate matter in the suspended load of the river. / The annual long-term discharge of dissolved ('226)Ra to the Gulf of Mexico is approximately 3.3 x 10('12) dpm yr('-1), about two orders of magnitude less than that discharged by the Mississippi River. Upon entrance into the Gulf, a portion of the particulate radium is released accounting for part of the high ('226)Ra concentrations observed in the estuary. Other possible radium sources to the estuary include submarine springs, seepage of coastal ground water and salt marshes. / Source: Dissertation Abstracts International, Volume: 47-12, Section: B, page: 4811. / Thesis (Ph.D.)--The Florida State University, 1986.
50

THEORY OF COASTALLY TRAPPED WAVES AND ITS APPLICATION TO THE YELLOW SEA

Unknown Date (has links)
The theory of coastally trapped waves has been developed for the bottom topography of two opposite continental shelves that meet along a common trough. The double shelf topography supports two sets of waves propagating in opposite directions. For this topography, the Kelvin waves are an important mode of motion; therefore the inclusion of the horizontal divergence effect is crucial. Other modes of motion are made up by the continental shelf waves. The double shelf model of straight coasts and constant cross-shore slope is applied to the Yellow Sea for the period of January 10 to April 12, 1986, during which direct observations in the trough of currents and bottom pressure were made. There is good agreement between the model results and the observations. The fluctuations of bottom pressure are chiefly accounted for by the Kelvin wave mode and those of the currents by the continental shelf wave modes. / Source: Dissertation Abstracts International, Volume: 48-07, Section: B, page: 1924. / Thesis (Ph.D.)--The Florida State University, 1987.

Page generated in 0.0801 seconds