This dissertation includes two fluid dynamics studies that involve fluid flows on vastly different scales, and therefore vastly different physics. The first study is of bacterial swimming using a flagellum for propulsive motion. Because bacteria are only about 10 [micrometers] in length, they swim in a very low Reynolds number (10⁻⁴) world, which is described by the linear set of governing equations known as the Stokes equations, that are a simplified version of the Navier-Stokes equations. The second study is of harmonic generation from nonlinear effects in internal, ocean-like wave beams that reflect from boundaries in a density stratified fluid. Internal wave reflection is an important oceanic process and may help sustain ocean circulation and affect global weather patterns. Such ocean processes have typical Reynold's numbers of 10¹⁰ or more and are only described by the full, nonlinear Navier-Stokes equations. In the low Reynolds number study, I examine theories by Gray et al.(1956) and Lighthill (1975) that describe swimming microorganisms using a helical flagellum for propulsive motion. I determine the resistance matrix, which can fully describe the dynamics of a flagellum, for flagella with different geometries, defined by: filament radius a, helical radius R, helical pitch [lambda], and axial length L. I use laboratory experiments and numerical simulations conducted in collaboration with Dr. Hepeng Zhang. The experiments, conducted with assistance from a fellow graduate student Chih-Hung Chen, use macroscopic scale models of bacterial flagella in a bath of highly viscous silicone oil. Numerical simulations use the Regularized Stokeslet method, which approximates the Stokeslet representation of an immersed body in a low Reynolds number flow. My study covers a biologically relevant parameter regime: 1/10R < a < 1/25R, R < [lambda] < 20R, and 2R< L <40R. I determine the three elements of the resistance matrix by measuring propulsive force and torque generated by a rotating, non-translating flagellum, and the drag force on a translating, non-rotating flagellum. I investigate the dependences of the resistance matrix elements on both the flagellum's axial length and its wavelength. The experimental and numerical results are in excellent agreement, but they compare poorly with the predictions of resistive force theory. The theory's neglect of hydrodynamic interactions is the source of the discrepancies in both the length dependence and wavelength dependence studies. I show that the experimental and simulation data scale as L/ln(L/r), a scaling analytically derived from slender body theory by my other collaborator Dr. Bin Liu. This logarithmic scaling is new and missing from the widely used resistive force theory. Dr. Zhang's work also includes a new parameterized version of resistive force theory. The second part of the dissertation is a study of harmonic generation by internal waves reflected from boundaries. I conduct laboratory experiments and two-dimensional numerical simulations of the Navier-Stokes equations to determine the value of the topographic slope that gives the most intense generation of second harmonic waves in the reflection process. The results from my experiments and simulations agree well but differ markedly from theoretical predictions by Thorpe (1987) and by Tabaei et al. (2005), except for nearly inviscid, weakly nonlinear flow. However, even for weakly nonlinear flow (where the dimensionless Dauxois-Young amplitude parameter value is only 0.01), I find that the ratio of the reflected wavenumber to the incoming wavenumber is very different from the prediction of weakly nonlinear theory. Further, I observe that for incident beams with a wide range of angles, frequencies, and intensities, the second harmonic beam produced in reflection has a maximum intensity when its width is the same as the width of the incident beam. This observation yields a prediction for the angle corresponding to the maximum in second harmonic intensity that is in excellent accord with my results from experiments and numerical simulations. / text

In the conventional approach to geophysical fluid dynamics, only the horizontal components of the Coriolis force due to horizontal motions of the fluid are taken into account. All the other components of the Coriolis force, which are called the non-traditional (NT) terms, are considered to be small second order quantities and are usually dropped. This effectively simplifies the system and the nice and clean quasi-geostrophic (QG) equation can be obtained, which is widely used in analytical studies of climate systems. Interest has been drawn to the dropped terms in recent studies. It is shown that in some special cases these second order terms actually have a noticeable influence on the dynamics of the system. However, a full picture of these terms in the dynamics of the real ocean is still lacking. Here, we will start from the fundamental equations of fluid dynamics, and through careful scaling analysis conduct a detailed study of the governing equations of geophysical fluid dynamics while keeping the NT terms. We will specifically investigate the influence of these NT terms on equatorial waves, since near the equator the NT components of the Coriolis force are the most significant. / text

The assessment of fragmentation is an important aspect of the design and planning of any excavation. The distribution of fragment sizes in situ helps assess the requirement of explosive energy to excavate the rock material. In addition, the information can also be used to evaluate the ground water flow, leaching characteristics and the requirement of additional rock handling equipment in construction projects. In the block cave mining method, the assessment of in situ and secondary fragmentation is an integral part of the design of the excavations at the extraction level and the selection of material handling systems for transporting the ore to the processing stations. Secondary blasting requirements can also be estimated based on the fragment size distributions developed for the block cave. Methods of estimating fragment size distributions in block cave mines have been based on joint set parameters estimated from structural mapping in available excavations or outcrops. While this is acceptable in the absence of any other means of assessing the fragmentation, the results can often be misleading since the structural mapping is often carried out in limited areas and the results applied uniformly to the entire deposit. This new study proposes to use the core piece lengths information gathered from the boreholes to develop in situ and primary fragmentation estimates for block cave operations. Under this proposed study, drill core piece lengths from an exploration program in Indonesia will be used along with structural mapping data to develop estimates for in situ and primary fragment size distributions. Methods for estimating secondary fragmentation from primary fragmentation will be evaluated and the estimates of secondary fragmentation from the different methods will be compared with the actual fragmentation characteristics observed at the drawpoints. The primary assumption in the development of primary fragment size distributions from drill core data is that each drill hole piece represents one in situ rock block. The relationships between the joint spacings and lengths of the different joint sets, evaluated from the joint set characteristics gathered from available excavations, outcrops or oriented core drilling programs, can be utilized for estimating the shape of the rock blocks.

The loading cycle in an Open Pit mine is a critical stage in the production process that needs to be controlled in detail for performance optimization. A comprehensive Alert System designed to notify supervisors of cycle times that are below the required performance standards is proposed. The system gives an alert message when one or several trucks are idle or the time of completing production tasks are over a predefined value. This alert is identified by the system and compared with pre-established Key Performance Indicators (KPIs) in order to determine corrective actions. The goal is to determine the strategies that help the production supervisor to optimize the haulage cycle model. A discrete-event simulator has been built in order to analyze different scenarios for route design and queue analysis. A methodology that utilizes different algorithms has been developed in order to identify the least productive times of the fleet. These results are displayed every time the simulation has finished. This research focuses on the optimization of haulage. However, the system is intended for implementation in subsequent stages of the production process, and the resulting improvement could impact mine planning and management as well. Topographic and drilling exploration data from a mine located hypothetically in the state of Arizona, were used to build a block model and to design an open pit; an Arena-based simulation was used to generate operating cycles that represent actual operations (As-Is model). Once the Alert System is implemented, adjustments were applied, and a new simulation was performed taking into consideration these adjustments (To-Be model), including comparative analysis and statistical results.

Covering approximately (57%) of the country's surface area the main basin of the geology of the Karoo Supergroup in South Africa has an important influence on the materials used in the construction of transport infrastructure in South Africa. The Karoo Dolerite Suite often serves as the only competent material in this otherwise sedimentary basin but on numerous occasions rapid premature failures of pavements constructed with Karoo Dolerite base courses have been attributed to the poor durability of these materials. The research presented here attempts to determine if the cause of such rapid failures can be attributed to dolerite durability deficiencies and if so if the durability of the material can be predicted using the current specifications to which these materials are required to conform with. The methodology followed was to perform comprehensive material investigations on selected pavement sections where Karoo Dolerite had been used as a base course aggregate. Eight suitable sites, ranging in age from two months to 10 years, were selected and comparative testing performed on samples of material obtained from the source quarries and pavement layers at each. Three of these sites experienced rapid failure that was suspected to be due to base course aggregate degradation. The tests performed included those specified by South African standards and a selection of new tests derived from published literature on alternative tests and proposed basic igneous rock degradation models. Well established tests were completed with relative ease while newer tests and newly proposed tests required additional development. The materials from at least two poor performance sites was shown to have undergone various degrees of degradation after quarrying which manifested itself primarily as a loss in resistance to attrition and abrasion forces. The variability in the inherent resistance of the material to these forces was also noted to have contributed to the poor performance of at least two sites. It is therefore proven that degradation of Karoo Dolerites after quarrying can occur and contribute to the poor performance of pavements but also that the variability in a source quarry can result in poor performance without material degradation. The prediction of material durability is possible but requires numerous tests to be performed on representative samples, particularly to identify variations in material properties. Petrographic properties that result in variable material properties and a susceptibility to further alteration included high degrees of deuteric and metasomatic alteration of primary minerals, especially the fine matrix minerals. It has been shown that the accurate quantification of such alteration is not feasible using easily available analysis techniques and therefore that no specifications can be based thereon. The current material specifications have been shown to not accurately predict the durability of Karoo Dolerite, primarily due to the inability to activate the mechanism by which material physical degradation occurs, namely the expansion of clay minerals within the aggregate. The only exception was the water absorption test performed on core samples, which was able to identify poor materials. Tests that were able to predict the durability included the modified versions of previously specified tests (e.g. ethylene glycol soaked aggregate impact value and ethylene glycol soaked modified durability mill index) and newly proposed testing methods (e.g. modified ethylene glycol durability index and shear wave velocity). Preliminary specifications for these have been proposed. The initial development of an aggregate expansion test has also shown a strong ability to predict Karoo Dolerite durability and is proposed for further development. Ultimately the use of poor durability Karoo Dolerite results in two changes in the material properties. The first effect is the production of more fines during construction, which can result in an unsuitable amount of fines (as identified by a low coarse sand ratio). The second effect is an increase in plasticity index and linear shrinkage of the material<0.425mm to levels considered marginal based on the current specifications. The shear strength of a Karoo Dolerite base course layer has been shown to be sensitive to such changes in plasticity index and linear shrinkage and the reduction of the current specification limit to ensure materials are non-plastic and/or non-expansive may therefore be justified.

This article provides a comprehensive reference list to the extensive studies of marine natural gas hydrate surveys and studies on the northern Cascadian margin of Western Canada. The references are divided into each of the major study methods, surveys, analyses and conclusions. A number of MSc and PhD theses are included. We first refer to the articles that address the local tectonics and sedimentary accretionary prism in which the hydrate forms, then those that describe the numerous geophysical and geological surveys and studies, and finally the articles that address the most important conclusions that have resulted from this work on the distribution , concentrations, and amounts of hydrates, and on the processes of hydrate formation and dissociation.

The self-potential method responds to the electrokinetic phenomenon of streaming potential and has been applied in hydrogeologic and engineering investigations to aid in the evaluation of subsurface hydraulic conditions. Of specific interest is the application of the method to embankment dam seepage monitoring and detection. This demands a quantitative interpretation of seepage conditions from the geophysical data. To enable the study of variably saturated flow problems of complicated geometry, a three-dimensional finite volume algorithm is developed to evaluate the self-potential distribution resulting from subsurface fluid flow. The algorithm explicitly calculates the distribution of streaming current sources and solves for the self-potential given a model of hydraulic head and prescribed distributions of the streaming current cross-coupling conductivity and electrical resistivity. A new laboratory apparatus is developed to measure the streaming potential coupling coefficient and resistivity in unconsolidated soil samples. Measuring both of these parameters on the same sample under the same conditions enables us to properly characterize the streaming current cross-coupling conductivity coefficient. I present the results of a laboratory investigation to study the influence of soil and fluid parameters on the cross-coupling coefficient, and characterize this property for representative well-graded embankment soils. The streaming potential signals associated with preferential seepage through the core of a synthetic embankment dam model are studied using the forward modelling algorithm and measured electrical properties to assess the sensitivity of the self-potential method in detecting internal erosion. Maximum self-potential anomalies are shown to be linked to large localized hydraulic gradients that develop in response to piping, prior to any detectable increase in seepage flow through the dam. A linear inversion algorithm is developed to evaluate the three-dimensional distribution of hydraulic head from self-potential data, given a known distribution of the cross-coupling coefficient and electrical resistivity. The inverse problem is solved by minimizing an objective function, which consists of a data misfit that accounts for measurement error and a model objective function that incorporates a priori information. The algorithm is suitable for saturated flow problems or where the position of the phreatic surface is known.

The occurrence of conductive sulphide in an otherwise highly-resistive host rock is the ideal situation for exploring using high-frequency electromagnetic methods. The FARA radio imaging (RIM) system was deployed to explore the rock properties between two boreholes MAC104 and MAC100G, which are about 182 m apart, on the Nickel Rim South property (MacLennan Township) 22 km northeast of Sudbury. Tomographic data were collected and processed at 625 kHz and 1250 kHz. One data set has the transmitter in MAC100G and the receiver in MAC104; the other “reciprocal” data set has the transmitter in MAC104 and the receiver in MAC100G. The amplitude data were reduced, edited, and processed to generate tomograms employing the SIRT algorithm. Separate tomograms were created for the reciprocal data sets in the ImageWin software. A sensitivity analysis was conducted to assess the influence that perturbations in the ImageWin processing parameters have on the resulting tomograms. The sensitivity study of the tomograms along with the information obtained from the value of fit analysis can be used to select appropriate processing parameters. Finally, the two reciprocal sets of conductivity values were averaged and imported into Geosoft to create a final tomogram for the panel. The resistivity values of the studied zone obtained from the FARA modeling package agree fairly well with the conductivity data set generated by the ImageWin modeling package when compared using the Geosoft and GOCAD visualization software. Differences between the two tomograms are attributed to the different solver methods employed by FARA and ImageWin and the statistical analysis used for averaging the attenuation value over ray paths. Furthermore, it is shown that the tomographic results are consistent with the location of conductive zones that were identified using down-hole geophysical logging. The main focus of the project is to understand how the radio imaging (RIM) data is processed with the ImageWin software to construct an attenuation tomogram. This research showed that both tomograms created by ImageWin and FARA illustrate the same pattern with two conductive zones at the same depth; however, the values of conductivity are slightly different. The FARA resistivity values obtained for the upper zone is a factor of two lower than the resistivity calculated by ImageWin. The resistivity values obtained for the lower zone using the FARA processing is a factor of eight lower than the resistivity calculated by ImageWin. Also, there is a slight discrepancy in the orientation of the upper and lower zones on the two tomographic images generated using the two processing packages. In the tomograms generated by FARA software both upper and lower zones are continuous linear zones from one hole to the other with dips from MAC104 towards MAC100G, whereas in the tomograms created by ImageWin the upper and lower zones are less linear and do not have obvious dips.

No description available.

The purpose of this investigation is to determine the effectiveness of projective well log analysis based upon data collected from Plummer Field located in Greene County, Indiana. Projective well log analysis consists of analyzing spontaneous potential (SP) logs from existing oil and gas wells in order to determine SP gradients that may be applied to locate other undiscovered hydrocarbon accumulations. Projective well log analysis was developed in 1963 by S.J. Pirson, however, the specific parameters employed in the Plummer Field investigation were developed in 1988 by Dr. R.H. Fluegeman in order to apply to the geologic conditions in southwestern Indiana.The results of this investigation indicate that SP gradients can be interpreted to determine hydrocarbon production potential in Plummer Field with a 62% to 73% certainty. Given the petroleum industry exploration success rate of 3% to 20%, it is believed that the SP gradients established in Plummer Field can be used to identify economical hydrocarbon accumulations in areas of similar geology such as other portions of the Illinois Basin and the Michigan Basin. / Department of Geology