This thesis investigates the variation of the chlorophyll-a concentration near Dongsha Atoll derived from MODIS Aqua and Terra satellite images, and their relationship to physical environments including sea surface temperature, CTD water qualities, tides, currents and surface winds for the period 2005 to 2008. The results revealed that the seasonal variation of chlorophyll-a concentration was higher in the winter than in the summer, and had inverse relationship with sea surface temperature. The increased chlorophyll-a concentration was due to entrainment of lower layer cold water with high nutrient. The upwelling water was induced by mixing of surface wind and internal wave shoaling. When the internal waves propagated westward to the Dongsha Atoll, the bottom topography and coastline oriented the cold deep water surged up slope to the northeastern corner of the Atoll, which produced high chlorophyll-a concentration a few days after. The comparison of MODIS images and CTD data revealed that the chlorophyll-a concentration didn¡¦t increase immediately after the passage of internal waves.

Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (leaves 102-107).

Thèse de doctorat : Chimie : Strasbourg 1 : 2008. / Titre provenant de l'écran-titre. Bibliogr. p. 207-220.

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 142-154). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph.D.)--Murdoch University, 2006. / Thesis submitted to the Division of Arts. Includes bibliographical references (leaves 284-327)

Thesis (M.S.)--Mississippi State University. Department of Electrical and Computer Engineering. / Title from title screen. Includes bibliographical references.

Thesis (Ph.D)--Industrial and Systems Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Bartholdi, John; Committee Co-Chair: Gue, Kevin; Committee Member: Goldsman, Dave; Committee Member: Griffin, Paul; Committee Member: Zhou, Chen. Part of the SMARTech Electronic Thesis and Dissertation Collection.

The load distribution across the contact line(s) of spur gears is essential for the gear designer to be able to accurately stress gears for a given application. Existing gear standards (eg BS 436, AGMA 218 DIN 3990) use a thin slice (2D) model of the meshing gear teeth to estimate the contact line load distribution. This approach clearly fails to model properly teeth subjected to mal-distributed loads, since the buttressing effect of adjacent tooth sections tends to flatten the load distribution. Non-linear tooth modifications such as crowning and some forms of lead correction are also inadequately modelled. This thesis sets out the theory for a 3D elastic model of widefaced- spur gears that has been implemented on a micro-computer. The required 3D contact line influence coefficients for standard form zero modification spur gears with 18 to 100 teeth have been determined by Finite Element analysis. These theoretical values have been compared with results from experiments carried out on a complete large module (18. Omm) wide-faced spur gear. The effect of the various elemental gear errors (eg pitch, profile, lead) and profile modifications have been investigated using the 3D computer model; the results compared with results predicted by the existing gear design standards. The existing gear standards use 2D tooth compliance values up to 50% less than those obtained in this work, largely due to inadequate modelling of the gear body compliance, which is most significant in gear wheels. Comparison of 3D tooth compliance values shows a large discrepancy between author's results again due to inadequate modelling of the gear body.

Impedance-based methods are used to locate faults on distribution systems because of their simplicity and ease of implementation. These methods require fault voltage and current data along with the positive- and zero-sequence line impedance values (in ohm per unit length) to estimate the reactance or distance to fault location. Inaccuracies in line impedance values, which arise from circuit model errors, have an adverse impact on fault location estimates of the impedance-based methods. Measurement errors in current and voltage transformers can also lead to inaccuracy in estimation. Further, all methods use simplistic models to represent the system load. The load in a practical distribution system does not conform to the oversimplified models leading to errors in estimation of fault location. This thesis presents sensitivity analysis of four impedance-based methods. It focuses on the Takagi, positive-sequence reactance, loop reactance and balanced-load methods. Amongst these four methods, the first three are commonly used for fault location. The fourth method was developed as a part of this work. The objective of sensitivity analysis is to study and quantify the effect of circuit model, measurement and load model errors, on the fault location estimates of the four methods. The results of this analysis are used to establish upper and lower bounds on the estimation errors for each method. The analysis begins with creation of a baseline case using a modified version of the IEEE 34 Node Test Feeder. All the methods estimate the reactance to fault location as a part of this analysis. The baseline case uses accurate line impedances and measurement values in the four methods. The fault location estimates for this case serve as a means of comparison for all subsequent analyzes. Secondly, various circuit model errors are introduced while computing the line impedance values. These errors include inaccurate modeling of four parameters viz. phase conductor distances, conductor sizes, phase to neutral conductor distances and earth resistivity. The erroneous line impedance values, which arise from these circuit model errors, are used in the four methods. The resultant location estimates are compared with those for the baseline case. It is observed that modeling errors in earth resistivity can cause estimation errors of 2% to 5% in the Takagi and positive-sequence reactance methods. These errors can be positive or negative depending upon whether the modeled earth resistivity value is more than or less than the accurate value. The effect of inaccurate modeling of the other three parameters is marginal. Additionally, the Takagi and positive-sequence reactance methods assume line impedances to be uniform while estimating fault location. Although this assumption is a type of circuit model error, it does not lead to significant errors in estimation. The loop reactance and balanced-load methods are insensitive to circuit model errors as they do not use line impedance values while estimating reactance to fault location. The next part is analysis of effect of measurement errors on fault location estimates. Ratio and phase angle errors are deliberately introduced in the current and voltage transformers and the erroneous measurements are used to conduct fault location. This causes 5% to 6% errors in estimation for the Takagi and positive-sequence reactance methods. These estimation errors can be positive or negative depending upon the magnitude of the CT and VT ratio errors and the sign of the phase angle errors. For the loop reactance method, erroneous measurements introduce 8% to 30% errors in fault location. This indicates that the loop reactance method is highly sensitive to measurement errors. The balanced-load method is moderately sensitive and experiences 6% to 7% errors in fault location estimates. Lastly, the effect of load current on fault location estimates is analyzed. When the Takagi and positive-sequence reactance methods are used on a heavily loaded system, they estimate fault location with an error of 5% to 8%. The loop reactance method is severely affected by the level of load current in the system. This method can estimate fault location with nearly 100% accuracy, on a lightly loaded system. However, the estimation errors for this method increase significantly and are in the range of 15% to 30%, as load current in the system increases. In case of the balanced-load method, unbalanced, heavy loads can cause estimation errors of 7% to 25%. The combined effect of all the error sources is taken into account by creating a confidence interval for each method. For the Takagi and positive-sequence reactance methods, the actual fault location can be expected to lie within ±10% of the estimated value. The fault location estimation error for the loop reactance and balanced-load methods is always positive. The actual reactance-to-fault is within -30% of the value estimated by these methods. / text

The k-distribution method for treating the spectral properties of and absorbing-emitting medium represents an alternative to line-by-line calculations which reduces the number of evaluations of the radiative transport equation from the order of a million to the order of ten without any significant loss of accuracy. For problems where an appropriate reference temperature can be defined, the k-distribution method is formally exact and consists only of a change of variables in the spectral domain. However, when no appropriate reference temperature can be defined such as for strongly non-isothermal media, the method results in errors. These errors are difficult to quantify. There have been several attempts to implement corrections to the k-distribution method to extend its application to inhomogeneous media by modeling the effects of temperature, pressure, and concentration gradient. The Multi-Source Full Spectrum K-Distribution Method (MSFSK) introduced here extends the k-distribution method to non-isothermal media without variations in pressure or concentration. The MSFSK method manages to attain this goal by applying the superposition principle to the original RTE before applying the k-distribution transformation to decompose the problem into a set of sub-problems each of which is able to be solved effectively via the ordinary or modified full spectrum k-distribution method. The concept behind this new Multi-Source Full Spectrum K-Distribution Method is to break up the problem domain into isothermal or nearly isothermal emission zones. For each zone, the heat flux and flux divergence are calculated considering only emission from that zone. The RTE is solved using the full spectrum k-distribution method. The k-distribution for each gas volume is generated using the temperature of the current emission zone as the reference temperature. This process is repeated for each emission zone and the heat flux and flux divergence are summed. This method is applied to a variety of one dimensional slab geometry problems are results are presented. It is shown that the MSFSK method provides very accurate results for the radiative heat flux and flux divergence in these geometries. The effect of different quadrature schemes for performing the spectral integration on solution accuracy. / text