Relevant bibliographies by topics / Surface marine / Dissertations / Theses
To see the other types of publications on this topic, follow the link: Surface marine.

Dissertations / Theses on the topic 'Surface marine'

Author: Grafiati
Published: 4 June 2021
Last updated: 1 February 2022

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 dissertations / theses for your research on the topic 'Surface marine.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.

1

Alme, Jon. "Autotuned Dynamic Positioning for Marine Surface Vessels." Thesis, Norwegian University of Science and Technology, Department of Engineering Cybernetics, 2008. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-8861.

Full text
Abstract:

Dynamic positioning of surface vessels involves control of vessels with changing dynamics, shifting conditions, for different operational tasks. A controller with fixed controller parameters cannot have an optimal performance for all these different cases, and autotuning of the controller would be very valuable. However, dynamic positioning is a complex task, and thus automatic tuning of a dynamic positioning controller is not less so. This thesis does not solve all problems that comes with autotuning of dynamic positioning systems, but it gives an overview of the problem and presents a novel performance index for station keeping. Furthermore, a hybrid controller that can function as a first step in solving the autotuning problem is suggested. The hybrid controller has a fixed controller structure and is a combination of a gain-scheduling controller and an adaptive controller. The adaptive controller is used in an idle (training/learning) mode to populate a look-up table with controller parameters, while the gain-scheduling controller work as a fast-changing dynamical controller, using the controller parameters stored in the look-up table. Each controller parameter set in the look-up table is optimized according to a vessel operational condition, which is defined as a function of environmental conditions (wind, waves, ocean current), vessel draught, and water depth. Optimization of the controller parameters for the different vessel operational conditions is carried out by two different autotuning methods; a genetic algorithm and a rule-based algorithm. Both of these autotuning methods are optimizing the controller gains in a nonlinear PID-controller. The performance index and the two autotuning methods are implemented in Matlab/Simulink, where simulation tests are performed for a 3 DOF mathematical model of a supply vessel. The test scenario includes two different vessel operational conditions, where the controller has been automatically tuned both for minimal position and heading deviation as well as weighting on the use of forces. A comparison of the two autotuning methods is also performed and finally a discussion of the behaviour and tuning of the suggested performance index is carried out.

APA, Harvard, Vancouver, ISO, and other styles
2

Angelopoulos, Christos K. "String stability of multiple surface marine vessels." Thesis, Monterey, California. Naval Postgraduate School, 2011. http://hdl.handle.net/10945/5676.

Full text
Abstract:
Approved for public release; distribution is unlimited.
The phenomenon of string instability is well known in a platoon of cars moving forward in an Automated Highway System (AHS). It is also known that ships can experience a similar instability phenomenon from mis-coordination of guidance and control laws. The proposed research studies the latter phenomenon, generalized in the case of multiple marine surface vessels moving in a platoon. The question of how it is possible for ships raveling in formation to exhibit the phenomenon of string instability is answered. Moreover, we examine under what conditions this phenomenon can be exhibited, as well as how it can be prevented.
APA, Harvard, Vancouver, ISO, and other styles
3

Zúñiga, Carlos A. "Small flux buoy for characterizing marine surface layers." Monterey, California: Naval Postgraduate School, 2013. http://hdl.handle.net/10945/34767.

Full text
Abstract:
Approved for public release; distribution is unlimited
A small easily deployable buoy, Marine-Air-Sea-Flux System (MASFlux), has been developed by the Meteorology Department of the Naval Postgraduate School. This system measures turbulence perturbations, mean wind and thermodynamic profiles, surface wave, and upper ocean temperature simultaneously. This research focuses on testing, documenting, and evaluating the MASFlux performance. The buoy system was tested in the Monterey Bay since August 2012 using small vessels, with the first three deployments focusing on sensor and buoy performance improvements. Concurrent measurements of wave and turbulence fluxes in the lower part of the atmospheric boundary layer during the last three deployments were not subject to apparent sensor errors or excessive mast rotations. Data from these deployments are analyzed here. The two-dimensional wave measurements were compared with those from the Datawell DWR-G4 wave buoys and showed consistent results in all deployments. Turbulent spectra analyses for data before and after buoy motion correction demonstrate the effectiveness in motion correction for the MASFlux. The spectra revealed a significant amount of energy in the atmospheric turbulence at frequencies of the dominant swell. The mean vertical wind profiles also indicated the effects of swell. These initial measurements and results point to great potential for the MASFlux for future air-sea-wave study.
APA, Harvard, Vancouver, ISO, and other styles
4

Qi, Yusheng Ph D. Massachusetts Institute of Technology. "Sea surface wave reconstruction from marine radar images." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/74939.

Full text
Abstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 103-105).
The X-band marine radar is one type of remote sensing technology which is being increasingly used to measure sea surface waves nowadays. In this thesis, how to reconstruct sea surface wave elevation maps from X-band marine radar images and do wave field prediction over short term in real time are discussed. The key idea of reconstruction is using dispersion relation based on the linear wave theory to separate the wave-related signal from non-wave signal in radar images. The reconstruction process involves three-dimensional Fourier analysis and some radar imaging mechanism. In this thesis, an improved shadowing simulation model combined with wave field simulation models for the study of the correction function in the reconstruction process and an improved wave scale estimation model using non-coherent radar data are proposed, which are of great importance in the reconstruction process. A radar image calibration method based on wave field simulation is put forward in order to improve the quality of reconstructed sea surface wave. Besides, a theoretical wave scale estimation model using Doppler spectra of the coherent radar is put forward, which is proposed to be a good alternative to the current wave scale estimation model. The reconstructed sea surface wave can be used for wave field simulation in order to predict the wave field, which is not only an application of this reconstruction process, but also a parameter optimizing tool for the reconstruction process.
by Yusheng Qi.
S.M.
APA, Harvard, Vancouver, ISO, and other styles
5

Lidbury, Ian. "Microbial methylated amine metabolism in marine surface waters." Thesis, University of Warwick, 2015. http://wrap.warwick.ac.uk/68959/.

Full text
Abstract:
Methylated amines, such as trimethylamine (TMA) and trimethylamine N-oxide, are nitrogenous compounds that are thought to be ubiquitous in the marine environment. TMA is a product of the anaerobic degradation of quaternary amines, such as glycine betaine and choline. Through a set of complex chemical and biological interactions, methylated amines play a role in regulating the planet’s climate. Microbial degradation of methylated amines is thought to be a sink for these compounds in the marine environment, however some of the key genes and enzymes responsible for the degradation of methylated amines are unknown. Using Ruegeria pomeroyi DSS-3 as the model organism, the key enzymes for the uptake and catabolism of trimethylamine N-oxide were identified and it was discovered that these genes and enzymes are highly expressed in the seawater, as revealed by the re-analysis of a number of recent metatranscriptomic and metaproteomic datasets. Again using R. pomeroyi as the model organism, it was shown that trimethylamine and trimethylamine N-oxide can be oxidised to CO2 to generate reducing equivalents and ATP. The generation of this reducing power results in a number of physiological benefits which are further discussed in detail. It was determined that bacteria possessing trimethylamine monooxygenase, the key enzyme required for the oxidation of TMA could also oxidise the reduced sulfur compound, dimethylsulfide, when supplemented with methylated amines. The ecology of methylated amine-utilising bacteria was investigated using a newly designed primer set targeting the trimethylamine N-oxide demethylase. The results are presented in detail within. The key genes and enzymes essential for the catabolism of the quaternary amine, choline were also discovered, again using R. pomeroyi as the model organism. The occurrence of genes required for the catabolism of choline are widespread among certain groups of marine bacteria known to interaction with eukaryotic biota, suggesting that this compound may be an essential nutrient for these organisms.
APA, Harvard, Vancouver, ISO, and other styles
6

Boppe, Ravi Shankar. "Structure of turbulence in the marine atmospheric surface layer." Diss., Virginia Tech, 1995. http://hdl.handle.net/10919/37461.

Full text
Abstract:
Turbulence research in the laboratory has confirmed the existence of quasi-coherent structures amidst the chaos of a turbulent boundary layer. It has been observed that a quasi-periodic phenomena called “bursting” accounts for a major contribution to the turbulent Reynolds stress and the production of turbulent kinetic energy. Bursting is the term used for a sequence of events, where a low-speed streak of fluid from the near wall region lifts away from the wall, slowly at first, and then rapidly moves away from the wall as it convects downstream where it becomes unstable and breaks up violently upon interaction with the outer flow. This ejection of low speed fluid into the mean flow is responsible for locally high values of turbulent kinetic energy. Although a great deal is known about these structures in laboratory flows, little has been done to investigate if such structures are universal in turbulent flows, i.e., their existence in large Reynolds number flows such as the turbulent air flow over the ocean. It would seem, intuitively, that such structures, if present in the marine atmospheric boundary layer, would play a major role in the transfer of momentum, mass and heat across the air-sea interface. It is speculated that these motions may also be associated with large scale organized motions in wall bounded turbulent shear flows. The effort aimed at elucidating the physics underlying such structures would be invaluable in contributing to our understanding of the air-sea flux mechanism. In this dissertation, standard ejection detection schemes like the quadrant, the VITA and the modified u-level techniques have been applied to turbulent wind data measured over the ocean to confirm the existence of burst like structures. The proportions of contributions to the Reynolds stress from the four quadrants of the u’w’ plane are in close agreement with the corresponding contributions for a laboratory flow. Ejection detection followed by the grouping of ejections into bursts yielded a mean burst period of 47 s, at a height of 8.2 m above the water surface, where the mean wind velocity was 6.74 m/s. This burst period corresponds well with the peaks obtained from the autocorrelation of the streamwise velocity signal and the first moment of the stress spectrum, confirming the quasi-periodic nature of this phenomena. Furthermore, phase averages of these events show a structure which is similar to the structure of events detected in laboratory flows. The ejection periods are seen to decrease with increasing wind speed. The burst periods decrease at first with increasing wind speed and then appear to attain a constant value after a wind speed of 6-7 m/s. This has been attributed to the breakdown of the grouping algorithm at higher wind speeds. Ejection and burst frequencies exhibit no discernible dependence on the surface wave field. Ejection and sweep motions have been studied at various length scales. The original velocity signal is bandpass filtered for various frequency bands. For each band, the percentage contributions to the Reynolds stress from the quadrants of the u'w’ plane are close to the corresponding quadrant contributions of the other bands. This indicates similar turbulence structure at different scales. The velocity signals for each band have been normalized by their root mean square (RMS) value. Visualizing the signals on nondimensional time shows the signals from each band to be very similar. These results can also be interpreted as evidence for the ejection and sweep motions existing simultaneously at different scales, indicating the fractal nature of these events. Large scale motions, which appear to be associated with ejection and sweep motions, have been identified in the marine atmospheric surface layer using velocity probe measurements at multiple heights. Visualizing these velocity signals suggests that the organized features extend across the depth of the surface layer. Converting the temporal signals to spatial fluctuations suggests that these structures are inclined at an angle while convecting downstream. The inclination angle near the surface (z < 18 m) is approximately 15° and it increases with increasing height to about 45° when z = 45 m. The spatial velocity fluctuations also indicate that these organized features may be large transverse vortical arches.
Ph. D.
APA, Harvard, Vancouver, ISO, and other styles
7

Battista, Thomas Andrew. "Lagrangian Mechanics Modeling of Free Surface-Affected Marine Craft." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/82928.

Full text
Abstract:
Although ships have been used for thousands of years, modeling the dynamics of marine craft has historically been restricted by the complex nature of the hydrodynamics. The principal challenge is that the vehicle motion is coupled to the ambient fluid motion, effectively requiring one to solve an infinite dimensional set of equations to predict the hydrodynamic forces and moments acting on a marine vehicle. Additional challenges arise in parametric modeling, where one approximates the fluid behavior using reduced-order ordinary differential equations. Parametric models are typically required for model-based state estimation and feedback control design, while also supporting other applications including vehicle design and submarine operator training. In this dissertation, Lagrangian mechanics is used to derive nonlinear, parametric motion models for marine craft operating in the presence of a free surface. In Lagrangian mechanics, one constructs the equations of motion for a dynamic system using a system Lagrangian, a scalar energy-like function canonically defined as the system kinetic energy minus the system potential energies. The Lagrangian functions are identified under ideal flow assumptions and are used to derive two sets of equations. The first set of equations neglects hydrodynamic forces due to exogenous fluid motions and may be interpreted as a nonlinear calm water maneuvering model. The second set of equations incorporates effects due to exogenous fluid motion, and may be interpreted as a nonlinear, unified maneuvering and seakeeping model. Having identified the state- and time-dependent model parameters, one may use these models to rapidly simulate surface-affected marine craft maneuvers, enabling model-based control design and state estimation algorithms.
Ph. D.
APA, Harvard, Vancouver, ISO, and other styles
8

Shuai, Hua. "Characteristics of Coherent Structures in Marine Atmospheric Surface Layer." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/36931.

Full text
Abstract:
Wind speed data of multi-heights have been examined to investigate the spatial and temporal characteristics of coherent structures in the near neutral marine atmospheric surface layer. With Taylor's hypothesis, the temporal velocity signals have been transformed to spatial fluctuations and then visualize these spatial velocity fluctuations to identify the coherent structures. It has been confirmed that there exist similar coherent structures in the marine atmospheric surface layer to those in laboratory turbulent boundary layer. These similar coherent structures include ejections, sweeps, shear layers, transverse vortices, and combined events of the shear layers and transverse vortices. Besides these similar coherent structures, there exist the plume and downdraft motions in the unstable marine atmospheric surface layer.

It has been observed that the streamwise spatial length of the ejections and sweeps is 20-250 m and their mean frequency is of order of 0.01-0.001 /s at mean wind speed of 5-12.6 m/s. Between the region of the upstream ejection and downstream sweep motions an inclined shear layer is often seen. The inclined angle of the shear layer has been observed to vary from 30 to 70 degree with the height and length of the the shear layer. The transverse vortices are seen to exist in every region from the wall up to a height of 45 m and their diameter is up to 40 m. The mean frequency of the shear layers and the transverse vortices is of order of 0.001 /s. In the fully developed stage of the combined event of the shear layer and transverse vortex, the shear layer is generally longer and the diameter of the transverse vortex is larger. The mean frequency of the combined event of the shear layers and the transverse vortices is of order of 0.001 /s. The streamwise spatial length of the plume and downdraft motions is generally from 20 m to 50 m.

Analysis indicates that the mean wind speed is a dominant factor in affecting the spatial and temporal characteristics of the coherent structures in the near neutral marine atmospheric surface layer. As the mean wind speed increases, the frequency of the shear related coherent events will increase, while the frequency of the buoyancy related coherent events (plumes and downdrafts) will decrease. The temperature difference between higher level of the surface layer and sea surface is the second main factor in affecting the spatial and temporal characteristics of the coherent structures. As the marine atmospheric surface layer becomes more stable the coherent motions will be suppressed. The effect of the temperature difference on the buoyancy related plume and downdraft motions is more evident than on the other shear related coherent motions.
Master of Science

APA, Harvard, Vancouver, ISO, and other styles
9

Johnston, Rodney G. K. "Deterministic free surface multiple removal of marine seismic data." Thesis, University of Edinburgh, 2000. http://hdl.handle.net/1842/12311.

Full text
Abstract:
This thesis presents a new method for sea surface multiple removal which includes in its solution the information at the source from the oscillating bubbles which generate the propagating wavefield. Arrays of interacting oscillating bubbles excite the earth with sound energy which is recorded as marine seismic reflection data. In the manipulation of the data to produce a detailed image of the earth's subsurface, the first task is the removal of multiple reflections related to the sea surface. The new formulation, in common with other wave-theoretical methods, requires a two-dimensional grid of receivers to record a two-dimensional grid of shots. Using the data themselves, and no information about the subsurface, all multiples are removed in a three-dimensional earth by calculating the plane wave reflection response in the frequency-wavenumber domain. Applying the plane wave concept to waves in three dimensions permits a complicated reflected wave to be decomposed into plane wave components. Each of these scattered upgoing plane wave components comprises primary and multiple reflections. The primaries result from a multiplication of an incident downgoing plane wave component with a plane wave reflection response, unique for the particular downgoing and upgoing plane wave components chosen. The multiples represent a sum of products of scattered downgoing plane wave components with plane wave reflection responses, related to the chosen downgoing and upgoing plane wave components. The result is a set of simultaneous equations whose unknowns form the three-dimensional reflection response. The wavefield from the oscillating bubbles produces the downgoing incident plane wave. There are various methods of measuring this input energy. They depend on the acquisition configuration being used, and the feasibility of placing hydrophones at certain distances from the sources of the oscillating bubbles. Consideration of the fluid dynamics of these oscillating bubbles, in isolation and together, and the wave propagation produced by them, reveals the requisite measurements to describe fully the acoustic output of the source.
APA, Harvard, Vancouver, ISO, and other styles
10

Johnson, Stuart. "Surface microtopography and the fate of seaweed propagules." Thesis, University of Liverpool, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333579.

Full text
APA, Harvard, Vancouver, ISO, and other styles
11

Loo, Hui. "Effect of surface waves on pollutant dispersion." Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk/hkuto/record.jsp?B23273185.

Full text
APA, Harvard, Vancouver, ISO, and other styles
12

Ulvé, Stephane. "Influence des propriétés de surface des peintures antisalissures marines sur le microfouling." Lorient, 2004. http://www.theses.fr/2004LORIS044.

Full text
Abstract:
Toute surface immergée en environnement marin est progressivement recouverte de biosalissures ou "Biofouling". La lutte contre cessalissures passe par l'utilisation de peintures antifouling dont la législation impose de réduire la toxicité imposant la compréhension des phénomènes impliqués et la recherche de nouvelles formulations. Une approche physico-chimique et microbiologique a permis de caractériser l'évolution des propriétés de surface des peintures, de leur polymère constitutif, et d'étudier leur influence sur l'adhésion de bactéries marines. L'analyse des propriétés de surface a montré que les peintures sont relativement proches les unes des autres et que leur hydrophilie est accrue après immersion. L'étude de la biodiversité in situ sur des peintures a montré une sélection des bactéries adhérentes basée sur la production de tensioactifs. Un grand nombre de paramètres sont à étudier et hiérarchiser pour progresser dans la compréhension du fonctionnement des peintures antifouling
Any surface immersed in sea water is gradually covered by biofouling. The use of antifouling paint is the best way to avoid biofouling. Legislation becomes more and more draconian. A better comprehension of involved phenomena is then required to find new formulations in order to reduce toxicity of marine paints. A physicochemical and microbiological approache made it possible by characterising the evolution of surface properties of paints and their constitutive polymers and by studying their influence on marine bacteria adhesion. The analysis of surface properties showed that paints had quite similar properties and that their hydrophily increased after immersion. In situ, a selection of adherent bacteria was found to be based on production of biosurfactant. A great number of parameters have to be studied in order to improve antifouling paint formulations
APA, Harvard, Vancouver, ISO, and other styles
13

Leedekerken, Jacques Chadwick. "Mapping of complex marine environments using an unmanned surface craft." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/68492.

Full text
Abstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2011.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 185-199).
Recent technology has combined accurate GPS localization with mapping to build 3D maps in a diverse range of terrestrial environments, but the mapping of marine environments lags behind. This is particularly true in shallow water and coastal areas with man-made structures such as bridges, piers, and marinas, which can pose formidable challenges to autonomous underwater vehicle (AUV) operations. In this thesis, we propose a new approach for mapping shallow water marine environments, combining data from both above and below the water in a robust probabilistic state estimation framework. The ability to rapidly acquire detailed maps of these environments would have many applications, including surveillance, environmental monitoring, forensic search, and disaster recovery. Whereas most recent AUV mapping research has been limited to open waters, far from man-made surface structures, in our work we focus on complex shallow water environments, such as rivers and harbors, where man-made structures block GPS signals and pose hazards to navigation. Our goal is to enable an autonomous surface craft to combine data from the heterogeneous environments above and below the water surface - as if the water were drained, and we had a complete integrated model of the marine environment, with full visibility. To tackle this problem, we propose a new framework for 3D SLAM in marine environments that combines data obtained concurrently from above and below the water in a robust probabilistic state estimation framework. Our work makes systems, algorithmic, and experimental contributions in perceptual robotics for the marine environment. We have created a novel Autonomous Surface Vehicle (ASV), equipped with substantial onboard computation and an extensive sensor suite that includes three SICK lidars, a Blueview MB2250 imaging sonar, a Doppler Velocity Log, and an integrated global positioning system/inertial measurement unit (GPS/IMU) device. The data from these sensors is processed in a hybrid metric/topological SLAM state estimation framework. A key challenge to mapping is extracting effective constraints from 3D lidar data despite GPS loss and reacquisition. This was achieved by developing a GPS trust engine that uses a semi-supervised learning classifier to ascertain the validity of GPS information for different segments of the vehicle trajectory. This eliminates the troublesome effects of multipath on the vehicle trajectory estimate, and provides cues for submap decomposition. Localization from lidar point clouds is performed using octrees combined with Iterative Closest Point (ICP) matching, which provides constraints between submaps both within and across different mapping sessions. Submap positions are optimized via least squares optimization of the graph of constraints, to achieve global alignment. The global vehicle trajectory is used for subsea sonar bathymetric map generation and for mesh reconstruction from lidar data for 3D visualization of above-water structures. We present experimental results in the vicinity of several structures spanning or along the Charles River between Boston and Cambridge, MA. The Harvard and Longfellow Bridges, three sailing pavilions and a yacht club provide structures of interest, having both extensive superstructure and subsurface foundations. To quantitatively assess the mapping error, we compare against a georeferenced model of the Harvard Bridge using blueprints from the Library of Congress. Our results demonstrate the potential of this new approach to achieve robust and efficient model capture for complex shallow-water marine environments. Future work aims to incorporate autonomy for path planning of a region of interest while performing collision avoidance to enable fully autonomous surveys that achieve full sensor coverage of a complete marine environment.
by Jacques Chadwick Leedekerken.
Ph.D.
APA, Harvard, Vancouver, ISO, and other styles
14

Carella, Giulia. "New estimates of uncertainty in the marine surface temperature record." Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/415483/.

Full text
Abstract:
Sea Surface Temperature (SST) represents the marine component of surface global temperature, the indicator underpinning the Paris Agreement. This thesis presents major advances in the understanding of the systematic biases and their uncertainty associated with changes in the observing protocol in the ship-only SST record since about 1850. First, by developing a method that probabilistically groups the observations in plausible ship tracks (and therefore potentially associates observations made with the same measurement method), the length of the tracks and the percentage of reports associated with individual platforms increased substantially. Following this analysis, the consistency of the SST was also found to have improved. Secondly, by comparing the SST diurnal variations observed by individual ships with a reference derived from drifting buoys, the SST measurement method was verified or estimated. Following this new classification of the changing ratio of bucket to engine-room inlet (ERI) observations, the difference between bucket and ERI SST anomalies in the period 1955 - 70 increased more rapidly when compared to existing estimates. Better and well validated physical models of SST biases in observations made with buckets were developed by comparing measurements made in the laboratory to predictions of models used in common gridded analyses to bias adjust SST observations made with buckets. Uncertainties due to the effects of turbulence and the assumption of well-mixed water samples were identified as a substantial limiting factor for the direct application of these models to the historical record. Building on the improved platform and observational metadata, SST observations from ships in the period 1992 - 2007 were bias adjusted by modelling their differences from climate-quality satellite data within a Bayesian hierarchical spatial model and as a function of the leading drivers characteristic to the observational biases for each measurement type. A comparison with existing bias adjustments, showed that current SST estimates for the past two decades might be characterized by undetected biases, especially in the ERI record, that could affect the estimates of global and regional surface temperature trends.
APA, Harvard, Vancouver, ISO, and other styles
15

Goodall, Robert Harry. "3D tooth surface texture analysis : methodological variability and marine mammals." Thesis, University of Leicester, 2017. http://hdl.handle.net/2381/39953.

Full text
Abstract:
Tooth microwear occurs when an animal processes food, producing microscopic pits and scratches on tooth surfaces, providing evidence of tooth movements and food properties. 3D microwear analysis is a growing field of study, where sub-micron scale tooth surface textures are used to compare populations with dietary differences. It has been primarily employed to study terrestrial vertebrates, however, the technique has rarely been applied to aquatic vertebrates, and never to aquatic mammals. Furthermore, the technique suffers from methodological variability. To address these points this thesis presents the results of five studies using 3D microwear analysis, three of which investigate different aspects of methodological variability, and two investigate the utility of 3D microwear analysis to differentiate diet in marine mammals, both across multiple species, and within a single species. An investigation of seven commonly used moulding compounds of varying viscosity demonstrated that mid-viscosity President Jet Regular Body produced the most accurate and precise moulds of tooth surface texture. An investigation was also carried out to test the effect of scale limiting 3D surfaces using 40 different combinations of operator (Nth order of polynomial) and filter to produce roughness surfaces. It was shown that high variability exists between resulting surfaces depending on the operator and the filter used. A combination of 6th order of polynomial, robust Gaussian filter and 0.025mm nesting index produced the greatest separation of known dietary groups while also being comparable to surfaces generated using many other combinations. An investigation into the effect of using four different microscopes to collect 3D tooth surface texture data showed high variability between resulting roughness parameter values and sensitivity to dietary differences depending on the microscope used. When testing the ability of 3D microwear analysis to separate ten marine mammal species into four known dietary groups, it was shown that this technique is highly sensitive to dietary differences, and provides information about the dietary evolution of extinct cetaceans. Finally, when using dentin tooth surfaces to test the ability of 3D microwear to detect differences between Orcinus orca dietary populations, it was found that their surface texture appears highly variable, and that little separation was possible between dietary groups.
APA, Harvard, Vancouver, ISO, and other styles
16

Kenny, Stephen. "In situ surface analysis of novel marine foul-release coatings." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/42564/.

Full text
Abstract:
Exposure of artificial surfaces such as ship hulls to a marine environment leads to the attachment of assorted biomolecules, single celled organisms and marine invertebrates such as barnacles or mussels. Together, they form a structure known as a biofilm. These films lead to higher fuel consumption and add considerable expense to the operation of ships used by industrial and naval organisations. The work presented in this thesis describes the surface analysis of a novel poly(dimethylsiloxane) (PDMS) based foul-release coating. The coating also contains poly(ethylene glycol) groups (PEG). The differing chemical properties between these two domains led to an observed surface modification effect in water, whereby contact angle measurements decreased from ~110o to ~65 o over a period of five minutes. This effect was rapidly reversible on drying. Time of Flight-Secondary Ion Mass Spectrometry cryogenic depth profiling experiments confirmed this change in surface chemistry where the frozen surface of the coating was shown to have a higher intensity of ions associated with PEG groups at the surface compared to that in the bulk. Water immersion also led to a swelling of the surface seen by a change in the surface topography by Atomic Force Microscopy investigations. When applied to glass surfaces the coatings were flat and generally defect free regardless of the application method used. On exposure to Pseudomonas aeruginosa the coatings were found to be ten times more effective at preventing bacterial adhesion in the first instance than a PDMS standard. The mechanism of action was shown to be non-toxic by live/dead staining and did not appear to affect the way in which bacteria move on a surface. A flow adhesion assay demonstrated that a flow rate of almost two orders of magnitude lower was required to remove fifty percent of bacteria from a coated surface than on a glass standard, demonstrating the foul-release ability of the switching coating. Sea trials in a French coastal region highlighted the importance of exposing candidate coatings to a true marine environment for a suitable duration in order to determine their potential for use. Ultimately we show that the coating presented is a candidate for use as an effective coating for preventing marine biofouling and surface analysis was deemed to be an appropriate methodology to analyse coatings that have changing properties on exposure to water.
APA, Harvard, Vancouver, ISO, and other styles
17

盧慧 and Hui Loo. "Effect of surface waves on pollutant dispersion." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31224866.

Full text
APA, Harvard, Vancouver, ISO, and other styles
18

Graham, Paul. "The non-stick approach to the control of marine fouling." Thesis, University of Portsmouth, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343379.

Full text
APA, Harvard, Vancouver, ISO, and other styles
19

DeRensis, Thomas P. "A robust linear dynamic positioning controller for a marine surface vehicle." Thesis, University of Rhode Island, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=1545508.

Full text
Abstract:

The autonomous surface vehicle (ASV) owned by the University of Rhode Island currently uses a PID controller that is insufficient for its maneuvering goals. The goal develop a robust linear controller based on state space models that is able to follow a given path with minimal error. A linear controller was developed that used inverse filters to follow a desired path with greater accuracy and used new methods for choosing feedback gains to provide greater H∞ robustness. The controller was tested in simulation by performing an ellipse maneuver on a nonlinear dynamic positioning model of the CyberShip II under disturbances, measurement noise, and model perturbations. It was found that these new methods tracked the desired ellipse with lower error than existing pole placement methods and no inverse filter. These methods show promise for real world implementation on URI's ASV once resources become available for approximate modeling.

APA, Harvard, Vancouver, ISO, and other styles
20

Oreopoulos, Lazaros. "Tropical marine stratocumulus albedo and its relation to sea surface temperature." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=56668.

Full text
Abstract:
A review of studies tackling problems on marine stratiform clouds is presented. The strong effect of marine stratocumulus clouds on the top-of-the-atmosphere radiation budget is demonstrated using 5 years of Earth Radiation Budget Experiment (ERBE) data. A relationship between albedo and sea surface temperature (SST) is shown to exist in two areas of the globe that tend to be covered by marine stratocumulus. Albedo increases when SST decreases and vice-versa in both regions when examined on an annual, interannual or spatial basis. The magnitude of the albedo response to a given SST change (1) varies within the regions; (2) differs between the two regions; (3) depends on the type of variability examined; (4) depends on the SST. No useful relations were found between albedo and other meteorological variables. Climatic implications on a global scale arising from the albedo-SST anticorrelation are also discussed.
APA, Harvard, Vancouver, ISO, and other styles
21

Mentzelos, Konstantinos. "Object localization and identification for autonomous operation of surface marine vehicles." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104299.

Full text
Abstract:
Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.
Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2016.
"June 2016." Cataloged from PDF version of thesis.
Includes bibliographical references (pages 99-100).
A method for autonomous navigation of surface marine vehicles is developed A camera video stream is utilized as input to achieve object localization and identification by application of state-of-the-art Machine Learning algorithms. In particular, deep Convolutional Neural Networks are first trained offline using a collection of images of possible objects to be encountered (navy ships, sail boats, power boats, buoys, bridges, etc.). The trained network applied to new images returns real-time classification predictions with more than 93% accuracy. This information, along with distance and heading relative to the objects taken from the calibrated camera, allows for the precise determination of vehicle position with respect to its surrounding environment and is used to compute safe maneuvering and path planning strategy that conforms to the established marine navigation rules. These algorithms can be used in association with existing tools, such as LiDAR and GPS, to enable a completely autonomous marine vehicle.
by Konstantinos Mentzelos.
Nav. E.
S.M.
APA, Harvard, Vancouver, ISO, and other styles
22

Breteau, Thomas. "USINAGE 5 AXES DE SURFACES GAUCHES CARACTÉRISÉES PAR UN CRITÈRE D'ÉTAT DE SURFACE ADAPTATIF." Phd thesis, Ecole centrale de nantes - ECN, 2010. http://tel.archives-ouvertes.fr/tel-00560042.

Full text
Abstract:
Ce travail, réalisé dans le cadre d'une thèse Allocation Couplée et un contexte inter-laboratoires fort : IRCCyN – IRENav – IFMA offrant de multiples ressources en productique et en hydrodynamique, vise à améliorer le processus de réalisation des hélices marines. Certaines des spécifications géométriques établies durant la conception perdent définitivement, lors de l'étape de définition de la stratégie de fabrication en finition, leur caractère fonctionnel au travers de leur traduction en paramètres liés à la machine d'usinage. Cette étude vise à proposer une alternative au polissage en renforçant les liens fonctionnels entre les propriétés de l'hélice et les paramètres géométriques des opérations de fraisage. La première partie du travail est consacrée à l'étude du processus de conception et de réalisation ainsi qu'au cycle de vieillissement des hélices marines. Les trajectoires d'usinage sont généralement obtenues par post-traitement du modèle numérique créé en C.A.O. ; passer directement des lois hydrodynamiques au trajet outil permet de mieux répondre aux exigences fonctionnelles des propulseurs marins. Ainsi des critères multiphysiques doivent être à la source de la spécification de l'état de surface, du format d'interpolation support des trajectoires et, dans le cadre d'une approche générique du processus d'usinage, du choix de l'ensemble des intervenants du processus de réalisation des hélices. Dans un second temps les relations entre les différentes activités du processus de fabrication des hélices sont restructurées et de nouvelles liaisons sont proposées entre les domaines dits « fonctionnel », « virtuel » et « physique » pour prendre en compte des contraintes fonctionnelles et ainsi aboutir à la mise en place d'un nouveau concept de génération de trajectoires d'usinage. Les lignes de frottements, signature hydrodynamique de l'hélice, sont suggérées pour supporter les trajectoires d'usinage. La complexité de ces données d'une part et celle de la géométrie hélice d'autre part nécessitent le développement d'une nouvelle stratégie de génération de trajectoires d'usinage. Ainsi, basés sur le formalisme de Bézier, des algorithmes d'interpolation sont proposés pour aboutir à des trajectoires continues au bord d'attaque, contrainte fonctionnelle incontournable et, chose essentielle, exploitables en usinage. Le passage par le bord d'attaque, lieu où la cavitation ne doit pas apparaître sous peine de se propager à l'ensemble de la pale, est l'objet de toutes les attentions. Les contraintes fonctionnelles insuffisantes en cet endroit sont, dans le cadre d'une approche multimétier, suppléées par des contraintes géométriques et des contraintes liées à la cinématique du centre d'usinage. Le trajet outil étant déterminé, une analyse de sa pertinence hydrodynamique est menée ; un découpage de la pale en zones d'application pertinente de la méthode est défini. Suite à cela, un modèle d'hélice de patrouilleur P400 de la Marine nationale est retenu comme cas d'étude. A partir de celui-ci, une étude expérimentale en bassin est mise en place en vue d'analyser, par comparaison avec une pale d'hélice étalon polie miroir, les effets de stries d'usinage orientées sur le comportement du fluide au voisinage d'une pale usinée selon la stratégie développée. Un fluide différent de celui d'évolution et une caméra rapide sont utilisés pour observer les modifications de comportement du fluide dues à l'état de surface dirigé. Les résultats de la campagne d'essais, qui reposent sur les techniques de traitement d'images, sont détaillés et analysés pour conclure sur les apports de la méthode en terme de coût et de temps de fabrication.
APA, Harvard, Vancouver, ISO, and other styles
23

Thorpe, Adrian A. "Alkyl and perfluoroalkyl siloxanes : synthesis, surface energies and antifouling performance." Thesis, University of Portsmouth, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322715.

Full text
APA, Harvard, Vancouver, ISO, and other styles
24

Pieper, Robert Joseph. "Surface Property Modification of Coatings via Self-Stratification." Diss., North Dakota State University, 2010. https://hdl.handle.net/10365/26491.

Full text
Abstract:
Biological fouling occurs everywhere in the marine environment and is a significant problem for marine vessels. Anti-fouling coatings have been used effectively to prevent fouling; however, these coatings harm non-targeted sea-life. Fouling-release coatings (FRC) appear to be an alternative way to combat fouling. FRC do not necessarily prevent the settlement of marine organisms but rather allow their easy removal with application of shear to the coatings surface. These coatings must be non-toxic, non-leaching, have low surface energy, low modulus, and durability to provide easy removal of marine organisms. Here the goal is to develop FRC based on thermosetting siloxane-polyurethane, amphiphilic polyurethane, and zwitterionic/amphiphilic polyurethane systems. A combinatorial high-throughput approach has been taken in order to explore the variables that may affect the performance of the final coatings. Libraries of acrylic polyols were synthesized using combinatorial high-throughput techniques by either batch or semi-batch processes. The design of the experiments for the batch and semi-batch processes were done combinatorially to explore a range of compositions and various reaction process variables that cannot be accomplished or are not suitable for single reaction experiments. Characterization of Rapid-GPC, high-throughput DSC, and gravimetrically calculated percent solids verified the effects of different reaction conditions on the MW, glass transition temperatures, and percent conversion of the different compositions of acrylic polyols. Coatings were characterized for their surface energy, pseudobarnacle pull-off adhesion, and were subjected to bioassays including marine bacteria, algae, and barnacles. From the performance properties results the acrylic polyol containing 20% hydroxyethyl acrylate and 80% butyl acrylate was selected for further siloxane-polyurethane formulations and were subjected to the same physical, mechanical, and performance testing. Amiphiphilic copolymers based on PDMS molecular weight and the addition of PEG based polymer blocks on the properties of acrylic-polyurethane coatings were explored. The key properties screened were surface energy, determined by contact angle measurements using water and methylene iodide, dynamic water contact angle, and pseudobarnacle adhesion properties. The data from all of the biological assays indicates that the novel coatings were able to resist fouling and have low fouling adhesion for the broad variety of fouling organisms tested.
APA, Harvard, Vancouver, ISO, and other styles
25

Zurn, Constanze Maria. "The interrelationships between surface and environmental properties, marine biofilms and larval settlement." Thesis, University of Newcastle Upon Tyne, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.512190.

Full text
APA, Harvard, Vancouver, ISO, and other styles
26

Xiao, Linlin [Verfasser], and Michael [Akademischer Betreuer] Grunze. "Influence of Surface Topography on Marine Biofouling / Linlin Xiao ; Betreuer: Michael Grunze." Heidelberg : Universitätsbibliothek Heidelberg, 2014. http://d-nb.info/1177888726/34.

Full text
APA, Harvard, Vancouver, ISO, and other styles
27

Black, Scott D. (Scott Donald). "Integrated lifting-surface/Navier-Stokes design and analysis methods for marine propulsors." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10398.

Full text
APA, Harvard, Vancouver, ISO, and other styles
28

Brinis, Anissa. "Biogéochimie de la microcouche de surface marine : approche par les biomarqueurs organiques." Paris 6, 2004. http://www.theses.fr/2004PA066027.

Full text
APA, Harvard, Vancouver, ISO, and other styles
29

Galhenage, Teluka Pasan. "Surface Optimization of Siloxane-Polyurethane Marine Coatings for Improved Fouling-Release Properties." Diss., North Dakota State University, 2016. https://hdl.handle.net/10365/29092.

Full text
Abstract:
Biofouling has been an economically and environmentally costly problem to mankind ever since they set sail. Biofouling causes frictional drag leading to slow vessel speeds, and increased fuel costs. Antifouling (AF) coatings containing biocides have been used for decades, however, since some biocides have shown undesired effects towards the environment, a non-toxic solution to combat fouling is desired. Subsequently, fouling release (FR) coatings quickly gained acceptance as a non-toxic approach to contend with biofouling. Unlike AF coatings, FR coatings not necessarily prevent settlement of organisms, they permit weak adhesion which is easily released by water shear or light grooming. The siloxane-polyurethane (SiPU) coatings based on the concept of self-stratification is a non-toxic and durable approach to prepare FR coatings. In this work, several approaches were considered to optimize surface properties of SiPU coatings. Incorporation of phenyl-methyl silicone oils led to improved FR properties towards several marine organisms in laboratory assays and in ocean field immersion. Enhancement in FR properties may be attributed to slowly exuding silicone oil providing surface lubricity, weakening the adhesion of marine organisms. Addition of diphenyldimethyl siloxane in to SiPU coatings at different ratios resulted in micro-scale surface topographical features which negatively affected microfouling-release while several coatings displayed good FR performance towards macrofouling organisms. In another study, decreasing the acid group content helped to improve FR performance towards barnacles, but FR performance towards diatoms were compromised. Novel amphiphilic siloxane-polyurethane (AmSiPU) coatings from polyisocyanate pre-polymers modified with polydimethyl siloxane and polyethylene glycol displayed excellent FR properties towards several marine organisms during laboratory assays. These AmSiPU coatings show promise as contenders to commercial FR standards. Initial development of SiPU coatings with hydrophilic surfaces showed promise, as the coatings showed rapidly rearranging surfaces with comparable FR performance to commercial standards which claim hydrophilic surface properties. During freshwater field immersion trials, SiPU coatings displayed excellent mussel FR performance up to 3 years. Surface analysis suggested that solvent content affected self-stratification and morphology of SiPU coatings. The SiPU coating system is a highly tunable, tough, environmentally friendly, and practical FR solution which can evolve along with non-toxic commercial marine coatings.
Office of Naval Research (Grant number N00014-12-1-0482)
SSPC
Valpar
American Coatings Association
North Dakota State University. College of Science and Mathematics
APA, Harvard, Vancouver, ISO, and other styles
30

Jeong, Seongsu. "Time Series Reconstruction of Surface Flow Velocity on Marine-terminating Outlet Glaciers." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1437602064.

Full text
APA, Harvard, Vancouver, ISO, and other styles
31

Sadri, Saeed Seyed. "Investigation of microplastic debris in marine surface waters using different sampling methods." Thesis, University of Plymouth, 2015. http://hdl.handle.net/10026.1/3363.

Full text
Abstract:
‘Microplastics’ are pieces of plastic debris < 5mm in diameter. They are introduced into the marine environment directly for example via release of small pieces of plastics used as abrasives and indirectly through the fragmentation of larger items. The European Marine Strategy Framework Directive 2008/56/EC (MSFD) regards microplastics as an emerging issue of concern and calls for more data on the quantity, distribution and composition of this debris. This thesis examines the amount, composition and distribution of buoyant microplastic debris in marine waters using different sampling devices and methodologies. To investigate the spatial distribution, abundance and composition of microplastic debris between nearshore and offshore marine subsurface waters a subset of samples from the Continuous Plankton Recorder (CPR) survey were examined. Abundance was generally higher in nearshore coastal waters than the offshore oceanic samples, with the highest mean concentrations observed in the UK’s coastal waters of the northeast Atlantic and the southern North Sea. To validate the accuracy of the presence/absence of microplastic debris reported in the Continuous Plankton Recorder (CPR) samples by analysts at the Sir Alister Hardy Foundation for Ocean Science (SAHFOS) a subset of data was formally analysed using Fourier Transform Infrared (FTIR) spectroscopy. This analysis indicated a good level of accuracy (~66%) in the ability of the SAHFOS’ analysts to detect visually microplastic fragments during their normal processing of plankton samples. To compare quantity and composition of buoyant microplastic debris collected by two different approaches (CPR vs. Manta net) samples were collected from a similar body of coastal waters. The results showed significantly higher abundance of microplastic in samples collected by the manta net per unit of distance but no significant difference once the results were standardised per cubic volume of water. To assess the susceptibility of each method to ‘procedural contamination’, repetitive controlled tests were conducted to quantify the amount and composition of contaminants before, during and after the sampling programme. In both methods the highest number of contaminants was found on the net and prior to the deployment to sea. The semi synthetic Rayon fibres were the most abundant type of contaminants in both cases. To compare the abundance and composition of buoyant plastic debris in estuarine waters according to daily and lunar tidal cycles a mensurative experiment was conducted in a macrotidal Estuary. Microplastics comprised 82% of the debris and there was a significant difference in size frequency distribution between the spring and neap tides with more fragments of larger size observed during spring tides. In conclusion, this study shows further evidence of the spatial heterogeneity of microplastic debris distribution in marine waters and therefore also highlights the need for more comparable data from different marine habitats using standardised methodologies.
APA, Harvard, Vancouver, ISO, and other styles
32

Wright, Alexander Mitchell. "Automated adaptation of spatial grids for flow solutions around marine bodies of complex geometry." Thesis, University of Southampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326861.

Full text
APA, Harvard, Vancouver, ISO, and other styles
33

Skandrani, Chafih. "Contribution à l'étude de la dynamique non linéaire des champs de vagues tridimensionnels en profondeur infinie." Aix-Marseille 2, 1997. http://www.theses.fr/1997AIX22123.

Full text
Abstract:
Le probleme de la dynamique des ondes de surfaces dans l'eau est toujours d'actualite et comporte plusieurs aspects qui restent a eclaircir malgre les efforts deployes jusqu'a present par plusieurs chercheurs. Meme en l'absence de vent, il existe divers phenomenes physiques, notamment ceux qui se rattachent aux interactions non lineaires des vagues qui demeurent incompletement expliques, d'ou la necessite de la poursuite des investigations sur la physique des interactions non lineaires entre les diverses composantes d'un champ d'ondes. Les resultats issus des modeles analytiques utilisant les equations de zakharov et de schrodinger non lineaire sont exposes. Leur limitation aux problemes faiblement non lineaire, leur fait preferer la modelisation numerique pour traiter les problemes d'ondes de forte cambrure. Notre etude a donc consiste, a explorer par voie numerique l'evolution de trains d'ondes bi et tridimensionnels en l'absence de vent et de deferlement. S'inspirant du formalisme de zakharov, le probleme est formule en termes de systeme dynamique complexe. La methode numerique utilisee est basee sur l'approximation pseudo-spectrale. En prenant comme condition initiale un train d'ondes de stokes soumis a des instabilites bidimensionnelles de type benjamin-feir en fluide parfait sans tension de surface, on a reproduit quelques resultats obtenus auparavant par differents auteurs, incluant le phenomene bien connu de la recurrence de fermi-pasta-ulam caracterise par le comportement symetrique des modes instables. Puis, on a etudie en detail, l'influence de la viscosite et de la tension de surface. Comme resultat, on a demontre que l'action combinee de ces deux effets conduit a un phenomene interessant deja observe experimentalement par plusieurs chercheurs, celui de la transition sous-harmonique en frequence et en nombre d'onde. Il se caracterise par le comportement dissymetrique des modes instables avec l'apparition d'une nouvelle frequence dominante plus basse du train. Nous avons etudie ce phenomene en detail, en utilisant aussi bien les transformees de fourier et de hilbert que l'analyse en ondelettes. L'extension du modele au cas tridimensionnel a permi d'observer et d'identifier deux types de structures tridimensionnelles en forme de fer a cheval. Nous avons pu etablir aussi la predominance du caractere bidimensionnel des instabilites.
APA, Harvard, Vancouver, ISO, and other styles
34

Zisman, Zachary Samuel. "On the Simulation of an All Electric Ship Powertrain Utilizing a Surface Piercing Propeller Via a Modular Main Propulsion Plant Model." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/33241.

Full text
Abstract:
A modular simulation model of a marine powertrain consisting of a prime mover, propeller shaft, propulsor, and control system was developed, tested, and used to demonstrate the ability to analyze the marine powertrain numerically. The modularity of the model allows for the user to easily substitute different or more advanced modules, or add additional modules to obtain a greater level of detail or simulate more complex interactions of systems with the marine powertrain. Current and historical trends indicate an interest in all electric ship design, and the use of surface piercing propellers for small craft. Due to the availability of towing tank data from a surface piercing propeller, an all electric prime mover module, surface piercing propeller module, propeller shaft module, and PID control module were coded, integrated, and operated, simulating a complete powertrain. Simulations were conducted using full-scale real-world conditions to demonstrate the model functionality and level of detail. Simulation results provided insight into the vibrational excitation, stability, and control of such a powertrain.
Master of Science
APA, Harvard, Vancouver, ISO, and other styles
35

Williamson, Robert I. "Relating an archive of in situ vertical chlorophyll-a profiles to concurrent remotely sensed surface data." Master's thesis, University of Cape Town, 2007. http://hdl.handle.net/11427/6443.

Full text
Abstract:
Includes bibliographical references (leaves 56-67).
Knowledge of the vertical distribution of phytoplankton in the upper ocean is essential for accurate estimates of primary production. Satellite remote sensing has given scientists an unprecedented view of near-surface chlorophyll distribution and other surface conditions, including sea surface temperature and wind data, from regional to global scales but little information on the dynamics below the surface. As a result estimates of global production tend to use regional profile averages but these methods oversimplify the smaller scale dynamics, particularly in coastal regions where productivity is highly variable on time scales of weeks. A pilot study by computer science honours students in 2006 showed the viability of using a Dynamic Bayesian Network (DBN) in predicting a representative profile per pixel of a satellite map based on a database of time series satellite surface data. In this study, 5813 in situ profiles were obtained from the highly dynamic upwelling region around the southwestern coastline of southern Africa. The samples were collected between 1988 and 2006 between the coast and the continental slope. The region was divided into three sub-regions according to biophysical processes: the west Coast; the west Agulhas Bank; and the east Agulhas Bank. Of the 5813 profiles, 5557 were included in the sub-regions. Two consecutive processes were then applied to the profile database. First, the profiles were clustered using a k-means clustering program which produced 16 representative clusters.
APA, Harvard, Vancouver, ISO, and other styles
36

Sandroni, Valérie-Anne. "Apports atmosphériques en mer Ligure : modes de dépôt, impact sur la couche marine de surface , implication dans les flux marins." Corte, 2000. http://www.theses.fr/2000CORT3050.

Full text
APA, Harvard, Vancouver, ISO, and other styles
37

Versteeg, Connie S. "Surface Associated Amoebae on the Ctenophore, Mnemiopsis sp." NSUWorks, 2007. http://nsuworks.nova.edu/occ_stuetd/103.

Full text
Abstract:
Previous work by Moss et al. (2001) reported surface associated protists on the ctenophore Mnemiopsis sp. They frequently observed the ciliate Trichodina ctenophorii and a Flabellula-like amoeba attached to the comb plate surface. They noted that the ciliate and the amoeba were found on the subsagittal, subtentacular, and the auricular comb plates. The amoeba had a maximum width of about 15 μm and cells were crescent shaped. Ultrastructural evidence suggested that these protists were parasites although the exact nature of the association remained to be determined. This was the background for the present study. The present investigation documented the frequency of occurrence of gymnamoebae on ctenophores around Florida to assess the universality of this association. In addition, the study estimated the number of Flabellula-like comb plate amoebae per comb surface. The study also set out to isolate all surface associated amoebae, including the Flabellula-like amoeba ‘symbiont’, using a variety of media formulations. The goal was to provide material to facilitate the identification and characterization of this amoeba. Over the 2 year duration of the project, 140 Mnemiopsis sp. were collected from 16 locations around Florida and surface tissue was processed for attached gymnamoebae. Eleven morphotypes of amoebae were isolated from 52 of the 140 Mnemiopsis sp. The Flabellula-like gymnamoeba was present on 85% of the specimens, and the greatest concentration on Florida ctenophores was 946 amoebae mm-2 of comb plate surface. One isolated amoeba closely resembled the Flabellula-like amoeba described by Moss et al. (2001). It is interesting to note that although most ctenophores harbored the ‘symbiont’ it was only isolated into culture 2% of the time. No geographic factors appeared to favor the presence of amoebae on ctenophores. The shortest generation time (ie. fastest growth) calculated for the flabellulid amoeba was 20.9 hours at a salinity of 10 ppt and a temperature of 23°C. The amoeba grew best in seawater supplemented with malt/yeast extract to stimulate the growth of attendant prey bacteria. The results suggest that this amoeba, which was numerous on the surface, was predisposed to life on the ctenophore surface and could only be switched to laboratory conditions with difficulty. The amoeba had an unusual stage in the life cycle forming large fused, multinucleate cells in old cultures. This, together with its unique appearance (not resembling any published species) and the problems in amplifying its DNA by PCR (encountered by collaborators at Wood’s Hole Oceanographic Center) suggest that it an interesting amoeba new to science.
APA, Harvard, Vancouver, ISO, and other styles
38

Gilliam, Robert Chad. "Influence of Surface Heterogeneities on the Boundary Layer Structure and Diffusion of Pollutants." NCSU, 2002. http://www.lib.ncsu.edu/theses/available/etd-20011228-115426.

Full text
Abstract:

Boundary layer processes are the dominating factors in the diffusion and transport of pollutants. Air pollution dispersion is known to be controlled by several boundary layer factors. Eddy diffusion, described by the amount of turbulent kinetic energy, is the main influence on how quickly a parcel of polluted air expands and boundary layer depth determines the extent of vertical mixing potential. This thesis explores the influence that mesoscale surface related features have on the boundary layer meteorology and air pollution dispersion through a combination of numerical model simulations and observations. Mesoscale processes including sea breeze and land breeze circulations, vegetation and soil type gradient induced circulations, urban heat island and terrain modified flows are addressed in this research through the use of various numerical simulations. Surface based observations from a meso-network and ground based remote sensing observations using two SODARs are examined. These observations are also utilized for model validation.

An observational analysis of 10 m micrometeorological tower measurements and collocated SODAR measurements is conducted for two different boundary layer events, which correspond to near neutral and convective conditions. SODAR data analysis of reflectivity and wind speed profiles is presented along with tower measurements of wind speed/direction (at 2 m, 5 m and 10 m levels) and the temperature difference between 10 m and 2 m. The analysis indicated dramatically different boundary layer structures during these events.

The near-neutral case shows that the boundary layer properties remained relatively constant during the 24-hour period, as indicated by the SODAR reflectivity that consisted of homogeneous echoes up to a height of about 100 m. The static stability, implied by the observed 10 m - 2 m temperature difference (ÄT10m-2m), supports a neutral, well-mixed boundary layer. The wind speed profile indicated time dependent fluctuations in magnitude associated with shear induced boundary layer eddies.

The convective case shows a rapidly increasing boundary layer during the early morning, just after sunrise. Strong fluctuating periods of high reflectivity during the day allude to convective boundary layer thermals. At the same time, near surface temperature gradient (ÄT10m-2m) shows strong buoyant instability. The overall convective pattern and associated boundary layer momentum is much different than that of the neutral case.

Numerical simulations, using the Advance Regional Prediction System (ARPS) includes an idealized tropical seabreeze simulation over India, a regional scale simulation over eastern North Carolina and a city scale simulation over Raleigh, North Carolina. Using both the seabreeze and city scale meteorological simulations, coupled ARPS-CALPUFF dispersion simulations are conducted to investigate the influence of the boundary layer meteorology on dispersion patterns.

The 5 km resolution seabreeze simulation shows that the boundary layer properties are distinctly different across a region that is affected by seabreeze circulations. The dispersion experiment from a point source near the coastline indicated that the seabreeze has a very noticeable effect on atmospheric dispersion overland. Higher surface concentrations are modeled during the seabreeze episode and the post seabreeze period later in the evening.

The regional numerical simulation (6 km grid spacing) over eastern North Carolina combined several interesting boundary layer scenarios. The typically warmer Sandhills region and some of the larger urban centers are simulated as warmer surfaces. Turbulence is also higher over these warmer locations. Landuse is shown to have a definite impact on the degree of simulated turbulence as well as the boundary layer height.

The high-resolution atmospheric simulation conducted over Raleigh, North Carolina is for the same case presented by the regional simulation. The 1 km model forecast shows large distinctions within the microscale boundary layer structure over the city scale domain. The boundary layer variations are directly related to the landuse parameterization. During the night, the model is sensitive to terrain variations. Over the more elevated areas the wind speed was overall higher, while noticeably weaker over low-lying areas. A simulated down slope flow at night is detected and associated temperatures are less in the low-lying areas. The data from both SODARs compares well with the simulated profiles.

Dispersion patterns utilizing the high-resolution meteorology are influenced by the landuse in several respects. The 1 km ARPS simulation showed microscale convergence zones develop along strong surface temperature and sensible heat flux gradients, which are mostly a result of vegetation differences between the urban areas in/around Raleigh and surrounding rural areas. In the dispersion simulation, these convergence zones are directly related to higher surface concentrations.

The elevation is shown to influence the wind field at night, therefore modifying the concentrations field. More elevated areas, specifically the higher north-south ridge in the western part of the domain is associated with slightly stronger wind at night and therefore lower concentrations. The lower lying areas are more stable as a cooler slope flow is established at night. This drainage flow allows pollutants to collect over some of the highly populated suburbs around Raleigh.

APA, Harvard, Vancouver, ISO, and other styles
39

Runco, Susan K. "The relationship between marine aerosol optical depth and satellite-sensed sea surface temperature." Thesis, Monterey, Calif. : Naval Postgraduate School, 1986. http://catalog.hathitrust.org/api/volumes/oclc/58046373.html.

Full text
APA, Harvard, Vancouver, ISO, and other styles
40

Song, Rui. "Path planning and collision avoidance of unmanned surface vehicles in the marine environment." Thesis, University College London (University of London), 2018. http://discovery.ucl.ac.uk/10042821/.

Full text
Abstract:
Efficient maritime navigation with the ability to avoid obstructions is an intensive research topic for autonomous navigation in ‘practical’ Unmanned Surface Vehicles (USVs). However, only few of the existing USVs have applied path planning in their navigation systems. Most studies present validation results at the simulation level and do not consider any environmental disturbances. The aim of this research project is to develop practical and efficient path planning algorithms that can generate and optimise the path based on known (or predicted) traffic and environment data with the ability to adapt to different criteria or missions. New risk assessment strategies together with three novel path planning algorithms have been developed to process and evaluate the real-time environmental conditions, to minimise the adverse effects caused by surface currents, and to improve the safety of the generated path for those circumstances where the reliability of the fused navigational data is uncertain. All these algorithms have been tested and verified in simulations with results proving the effectiveness of path generation and low-cost of energy consumption. Experiments using a practical USV have also been carried out to validate the capabilities of the algorithms.
APA, Harvard, Vancouver, ISO, and other styles
41

Wong, Felicia Wong Yen Myan. "The influence of physical attributes of surface topographies in relation to marine biofouling." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/38837/.

Full text
Abstract:
Solid surfaces that spend long periods of time in aquatic environments are susceptible to the accumulation of marine fouling organisms and this phenomenon is known as marine biofouling. This is a natural process which has significant impacts on marine industries. Research to develop new antifouling solutions focuses on the development of non-toxic solutions that can deter biofouling. A non-toxic antifouling approach that has gained interest in recent years is to modify the surface’s structure to disrupt organism settlement (Kirschner and Brennan 2012; Magin et al. 2010; Myan et al. 2013). Many studies determined that uniform arrays of single layered, micro-topographies are effective at deterring the initial settlement of fouling organisms. In contrast, most studies that tested uniform arrays of single layered, macro-topographies concluded that these topographies are not suitable for antifouling applications. Both single layered, micro-topographies and single layered, macro-topographies were determined to have limitations at mitigating biofouling. This resulted in the interest to develop hierarchical topographies. Hierarchical topographies are surfaces that consist of features that are varied in size and shape. It was suggested that the diverse nature of hierarchical topographies might be able to deter biofouling from a wider array of organisms. This research fabricated and tested a wide range of topographies (uniform, non-uniform, micro, macro, hierarchical, etc.) in a field study. A field study was preferred over lab experiments because results will reflect the antifouling efficacy of the surfaces in a marine environment. These results will indicate the topographies’ viability and future potential for industrial applications. Antifouling efficiency was evaluated by measuring fouling resistance (during the field test) and fouling removal (after the field test) of all topographies. Physical attributes (pattern geometry, pattern size, and surface roughness) of topographies were characterised with Scanning Electron Microscopy (SEM) and Laser Scanning Confocal Microscopy (LSCM). Statistical analysis was carried out to evaluate the significance of the topographies’ physical attributes on the antifouling efficiency of the topographies. The research hypotheses predicted that topography size, geometry and surface roughness will affect the topographies’ ability to resist biofouling. All patterned surfaces were predicted to have a higher resistance to biofouling in comparison to un-patterned control surfaces (i.e. smooth surfaces). The possibility that hierarchical topographies would have better fouling resistance properties than micro-topographies was considered as well. Hierarchical topographies and micro-topographies were also hypothesised to demonstrate better resistance to biofouling than macro-topographies. Topographies with straight ridges and hierarchical shapes were predicted to be more fouling resistant than sandpaper surfaces. Topographies with average roughness (RSa) that were less than 100µm were assumed to exhibit better antifouling efficacy in comparison to topographies with average roughness greater than 100µm. Results showed that pattern size and pattern geometry affects the antifouling efficiency of topographies. Unexpectedly, surface roughness did not show strong correlations with the fouling resistance of the topographies. With the exception of Sandpaper 50 and Sandpaper 1mm samples, all topographies were more fouling resistant than the control samples (i.e. smooth surfaces). Among the 16 topographies, sandpaper 1mm samples demonstrated the worst defence against biofouling. The mean total fouling coverage on these samples after 10 weeks of tests was 98.7%. Straight, single layer ridges demonstrated the best resistance to total fouling during the field test. Barnacle and polychaete settlement trends were affected by the size and geometry of single layer, single sized topographies. After 10 weeks, the mean total fouling coverage on these ridges was only 37.5%. The field test also showed that the topography with the best prolonged resistance to fouling was the 1mm straight ridges. The combination of structured surfaces and a low modulus material is likely to have contributed to the fouling removal properties of all topographies. Lastly, results from the field study also showed that hierarchical topographies do not necessarily have better antifouling properties than single layer, single sized topographies. The field study demonstrated that the physical attributes of topographies contributed to their antifouling efficiency. It has been suggested that the physical characteristics of topographies induces hydrodynamic variations that affects the surfaces’ antifouling properties. However, it is difficult to observe these changes in lab experiments or through field studies because these variations take place at a very small scale. Recent research has applied Computational Fluid Dynamics (CFD) to numerically simulate and analyse flow characteristics in the surrounding areas of antifouling topographies. As a continuation from the field study, the next study in this research applied CFD to analyse flow characteristics over several topographies that were tested in the field study. This was to determine if the settlement trends exhibited by organisms in the field study could have been affected by hydrodynamic variations that were induced by the presence of the topographies. The CFD analysis showed that rotational vortices formed between topography patterns. These vortices could have aided in the accumulation of biofouling material on all topographies during the field test. The analysis also showed that the topographies’ resistance to fouling could be attributed to high shear stress and strain rate zones at the peaks of the topographies. Comparisons between CFD and field test results indicate that higher stresses and strain rate zones around the topographies are likely to lead to a surface’s better resistance to marine biofouling. This is likely because high shear stress and strain rate zones could have disrupted organism motility and made the surface less conducive for settlement.
APA, Harvard, Vancouver, ISO, and other styles
42

Hanson, Christopher J. (Christopher John) 1971. "Integrated lifting-surface and Euler/boundary-layer theory analysis method for marine propulsors." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/91328.

Full text
Abstract:
Thesis (Nav.E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001.
Includes bibliographical references (leaves 62-63).
by Christopher J. Hanson.
Nav.E.
S.M.
APA, Harvard, Vancouver, ISO, and other styles
43

Kampezidou, Dimitra. "Spatial distribution of heavy metals in surface marine sediments in the Mediterranean region." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-111066.

Full text
Abstract:
Several scientific articles were mainly reviewed from Umeå’ s university database in order to determine the distribution, degree of contamination, and the sources of 7 selected heavy metals (Cr, Pb, Cu, Zn, Cd, Hg, Ni) in surface sediments along the coasts of the Mediterranean Sea. The Enrichment factor (EF) was used as pollution indicator to evaluate the extent of metal contamination in all the investigated areas. According to Abrahim and Parker (2008) the EF is defined as the ratio of the determined metal to Al (or Fe) in the sample divided by the ratio of background metal to background Al (or Fe) ratio. According to the results of this study, EF values for Cr, Pb, Cu, Cd and Ni presented an upward trend along the west to east shoreline of the Mediterranean sea, whereas Zn and Hg EF values showed a downward trend along this region. Cr generally exhibited no enrichment in places to the west (EF<1.5) whereas in the eastern side displayed moderate enrichment (EF=1.95). Pb EF values showed moderate enrichment (EF=5) along the western section of the sea, whilst in the eastern part revealed significant enrichment (5.45). Zn pollution levels were minimal (EF=1.6) in places to the west and moderate (EF=2.2) to the east. The enrichment for Cd was considered moderate in the western part of the basin and significant in the eastern section. These heavy metals distribution can be explained by the fact that different inputs (mainly due to anthropogenic activities) from the inshore environment may take place in each area of the sea. However, Cu and Ni presented the same degree of pollution (moderate) in the whole sea, presumably indicating similar Cu and Ni inputs from the terrestrial environment. However, conclusions for Hg were not possible to be drawn as the collected data were not sufficient.
APA, Harvard, Vancouver, ISO, and other styles
44

Roberts, Scott D. "Stability analysis of a towed body for shipboard unmanned surface vehicle recovery." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Mar%5FRoberts.pdf.

Full text
APA, Harvard, Vancouver, ISO, and other styles
45

O'Donoghue, Thomas. "The dynamic behaviour of a surface hose attached to a calm buoy." Thesis, Heriot-Watt University, 1987. http://hdl.handle.net/10399/1045.

Full text
APA, Harvard, Vancouver, ISO, and other styles
46

Jagodziński, Robert. "Petrography and geochemistry of surface sediments from Sunda and Vietnamese shelves (South China Sea) /." Poznań : Wydawn. Naukowe, 2005. http://www.loc.gov/catdir/toc/fy0801/2007422802.html.

Full text
APA, Harvard, Vancouver, ISO, and other styles
47

Bowie, Andrew Ross. "Flow injection with chemiluminescence detection for the determination of iron in surface Atlantic waters." Thesis, University of Plymouth, 1999. http://hdl.handle.net/10026.1/1683.

Full text
Abstract:
This thesis describes the design, optimisation and shipboard deployment of a flow injection - chemiluminescence (FI-CL) technique for the determination of iron (Fe) in seawater. Chapter One presents an overview of the marine biogeochemistry of Fe, including its speciation, sources and sinks, abundance and limitation for phytoplankton growth in the Wodd*s oceans. Current analytical methods for the determination of Fe in natural waters are also reviewed. Chapter Two reports the instrumental development of the FI - CL method. Each component is described and its suitability to the flow manifold discussed. Different CL detection systems are evaluated and a charge coupled device used to investigate the spectral profile of the Fe-catalysed luminol reaction. Automation of the FI manifold is also detailed along with acquisition of CL signals. Chapter Three details the optimisation of a FI - CL procedure for the determination of Fe in seawater. Reagent clean-up techniques, blank procedures and a standard addition operating routine are detailed. Fe(III) reduction using sulphite is treated theoretically. Matrix effects are investigated and the synthesis of an 8-hydroxyquinoline resin used for in-line matrix elimination and preconcentration is reported. The optimised method is selective to Fe(II+IIl) in the linear range 0.04-10 nM, with a precision of 3.2% (n=5) for a LO nM standard and a limit of detection (3s) of 40 pM for a load time of 1 min. Chapter Four presents the results of an investigation into the kinetic effect of Fe on luminol CL using the continuous addition of reagent (CAR) technique. Instrumental and chemical parameters are optimised, interferences investigated and the CAR-CL technique compared with alternative flow configurations. In Chapter Five, the application of the F - CL method to the shipboard determination of Fe in the surface North and South Atlantic (SO'^N to 50°S) is presented. Data are reported for samples collected from the upper water column (<200 m) in eight different biogeochemical provinces, which represent coastal, upwelling and oligotrophic regions of the Adbntic Ocean. Total dissolvable iron (unfiltered, TD-Fe) levels range ftom <0.1 to 6.1 nM and indicate that high and spatially variable TD-Fe (>2 nM) concentrations exist in Equatorial and tropical North Atlantic regions influenced by atmospheric deposition from the West African continent. Away from strong input mechanisms, TD-Fe concentrations in the upper water column average 0.6 nM. Input sources are fingerprinted via correlation with other trace metals (Al, Co, Ni), nutrients and hydrography, whilst active biological uptake is shown to be the dominant sink. TD-Fe vertical distributions through the upper mixed layer display strong relationships with chlorophyll a concentrations, and measurements in the deep chlorophyll maximum of the South Atlantic oligotrophic gyre show that, despite elevated nitrate at such depths, Fe concentrations are at a minimum (ca. 0.1 nM) and may be low enough to (co-)limit phytoplankton growth.
APA, Harvard, Vancouver, ISO, and other styles
48

Lockwood, Amy M. "Evaluation of Corrosion and Wear of Non-Skid Deck Surfaces in Marine Environments." Digital WPI, 2010. https://digitalcommons.wpi.edu/etd-theses/470.

Full text
Abstract:
The annual cost of corrosion in the United States Navy and Coast Guard is in excess of $2.7 billion dollars. The salt water environment provides a ripe surrounding for rapid corrosion and deterioration of ship decking, which requires frequent and expensive maintenance. Decks of ships are susceptible to corrosion and wear, but must also maintain a non-slip surface in a constantly wet environment. Few options for non-skid deck materials are currently approved for use by the Navy and require frequent and expensive maintenance or replacement. A new material known as Laser Deposited Non-Skid, currently used in industrial flooring applications, shows potential for serving as a more durable non-skid material with extended service life and greater resistance to corrosion. The purpose of this research is to investigate the feasibility of Laser Deposited Non-Skid in decks of ships and to compare the corrosion, wear and cost data with existing deck materials. Sample plates of A36 and A572 steel and 5086 and 5456 marine grade aluminum alloy were coated with selected non-skid materials and subjected to laboratory salt fog testing and corrosion in environmental conditions in the Caribbean Sea. Wear behavior among non-skid materials was evaluated through wear cycles, measurement of coefficient of friction, and surface characterization. Salt fog testing was more corrosive than the actual operational environment in all cases and the Laser Deposited Non-Skid samples had the best resistance to wear and corrosion. The Peel and Stick Non-Skid demonstrated corrosion by undercutting while the Traditional Non-Skid corroded through the material. The relative area did not correlate well with friction or wear mass loss. Aluminum Laser Deposited Non-Skid appears suitable for use as a deck material on small boats. More research is needed to evaluate maintenance issues and possible stress cracking associated with the Laser Deposited Non-Skid on steel decks.
APA, Harvard, Vancouver, ISO, and other styles
49

Grossman, Laura A. "The Impact of Sea Surface Temperature on Outbreaks of Acanthaster planci on the Great Barrier Reef." Scholarship @ Claremont, 2014. http://scholarship.claremont.edu/scripps_theses/306.

Full text
Abstract:
The causes of increasing outbreaks of Acanthaster planci on the Great Barrier Reef have been a point of hot debate in recent years. It is unknown whether the increased success is due to nutrient runoff, salinity levels, or a decrease in predation, among other possibilities. In this paper I argue that the primary influence on outbreak status is sea surface temperature. From existing literature, I demonstrate that sea surface temperature in the Great Barrier Reef has increased by 0.4°C per year over the past three decades. I attempt to tie this increase with an increase in frequency of A. planci outbreaks on a selection of reefs throughout the Great Barrier Reef region. Due to the development of A. planci, specifically the fact that it takes them between 2 and 3 years to reach full maturity, I examined the potential relationship between an outbreak and the sea surface temperature 1 and 2 years before the event. Through my exploration of the data and my subsequent data analysis, it is clear that there are no statistically significant results when comparing the three classifications of outbreak (active, incipient, and recovering) and not outbreaking populations with temperature at each of the three time relationships. However, when I considered the three stages of outbreak to be “affected” and those not outbreaking to be “unaffected”, I found a statistically significant relationship. This finding has important implications when looking at the temperature changes that have been predicted for the Great Barrier Reef region due to global climate change. If the water temperature continues to increase, A. planci will more often be living within their optimal temperature range and will be more successful, continue to have major outbreaks that devastate the reef ecosystem, and eventually destroy it all together.
APA, Harvard, Vancouver, ISO, and other styles
50

Palmer, Trisha Denise. "The Role of Land-Surface Hydrology on Small Stream Flash Flooding in Central North Carolina." NCSU, 2004. http://www.lib.ncsu.edu/theses/available/etd-08122004-004241/.

Full text
Abstract:
In order to determine the influence of various factors on flash flooding, six case studies during which flash flooding occurred across central North Carolina are examined: 1) 26 August 2002, 2) 11 October 2002, 3) 9-10 April 2003, 4) 16 June 2003, 5) 29 July 2003, and 6) 9 August 2003. Utilizing stream gage data from the United States Geological Survey combined with radar-estimated precipitation from the Weather Surveillance Radar-1988 Doppler (WSR-88D) KRAX near Clayton, NC, several statistical conclusions are drawn. These conclusions are based on relationships between the inputs ? rain rate and precipitation amount ? to the stream responses: the amount of time between when the stream began its rise and when the maximum stage was reached, the amount of time between the onset of precipitation and the initial response of the stream, the maximum stage reached, the change in height of the stream, and the rate of change of height of the stream. Results indicate that precipitation rate and amount tend to dominate the influence of stream response; however, in many situations, land-surface characteristics play an important role. The notable situations where precipitation rate and amount do not dominate are along the major rivers, in locations with sandy soils where infiltration is high, and in urban areas, where runoff occurs rapidly and streams thus respond quickly regardless of precipitation rate or amount. In addition, rain rate and precipitation amount do not necessarily have similar relationships with the stream response variables; rain rate has a stronger correlation with rate of change of stream rise, while precipitation amount has a stronger correlation with change in stream height. However, it is not enough to study rainfall rates and precipitation amounts if a flash flood warning is to be issued. The results of this research show that there is value and necessity in understanding the role of land-surface characteristics when determining if flash flooding is going to occur.
APA, Harvard, Vancouver, ISO, and other styles
You might also be interested in the bibliographies on the topic 'Surface marine' for other source types:
Journal articles Books
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography