A laboratory experimental programme was carried out to investigate the behaviour of the piezocone in lightly over consolidated clay. The clay samples were prepared from reconstituted kaolin. The powdered form of this clay was mixed with water to form a slurry at a moisture content of approximately 120% under vacuum. The clay slurry was consolidated and then allowed to swell in chambers which were well instrumented. Penetration tests were carried out with two sizes of piezocones. The smaller piezocone had a cross sectional area of 1cm² with pore pressure measurement at the cone shoulder. The larger piezocone with a cross sectional area of 5cm² had pore pressure measurements at four locations. In addition to penetration testing, further information on the strength and consolidation characteristics of the test chamber samples was obtained form shear vane, restricted flow consolidation, flow pump permeability and consolidated undrained triaxial tests. The horizontal effective stress and the vertical stress ratio were found to influence the generated excess pore pressure at all four different locations on the piezocone shaft and the net tip resistance. This led to the establishment of direct correlations for the tip resistance factor Q with the coefficient for lateral earth pressure at rest Ko and the vertical effective stress ratio (OCR). Direct correlations for the excess pore pressure ratio at all four measuring positions with Ko and OCR were also established. Several methods of estimating over consolidation ratio were examined. One of the factors examined was Bq which was found to correlate poorly with OCR before tending asymptotically to a value of approximately 0.4. Other examples of factors which showed promising results as estimators of OCR were Bmi, the excess pore pressure ratio, and Q, the tip resistance factor. The excess pore pressures well behind the cone shoulder, which are partly generated by the shear stress in the area, showed promising correlations with the undrained shear strength. However, because correlations with pore pressure on the piezocone are dependent upon the position of the filter element, the particular results from this series may only be used for piezocones whose filter elements are at equivalent positions. The undrained strength ratio was also correlated with the tip resistance factor Q and the result was very promising for future interpretation of piezocone data.

The cone-pressuremeter is a new site investigation device which incorporates a pressuremeter behind a standard cone penetrometer tip. This dissertation is concerned with an understanding of the new device, and in particular the establishment of a detailed procedure to allow the test to be used to determine the engineering properties of cohesionless soils. A series of 34 calibration tests was performed, in which three cone-pressuremeter prototypes with cross-sectional areas corresponding to 15cm², 10cm² and 5cm² were used. The tests were carried out on cylindrical samples, enclosed in a chamber 1.0 m in diameter and 1.5 m in height. Stress controlled boundaries allowed independent control of vertical and horizontal stress in the range of 50 kPa to 300 kPa. A raining deposition technique was used to produce three sand densities, corresponding to loose, medium and dense samples. A programme of calibration was designed to provide an examination of the influence of relative density, stress level and stress ratio on cone-pressuremeter test data. Soil properties were related to the values of the limit pressure obtained from the pressuremeter test and the cone resistance values from the cone test. Empirical relationships were proposed for deriving density, friction angle and horizontal stress. Cone-pressuremeter tests were used for assessing directly the shear stiffness of the soil. A series of calibrations was needed to obtain the best possible estimation of the unload-reload shear modulus. Interpretation of the measured modulus was made by examining appropriate methods of calculating the modulus from unload-reload loops. Strain arm measurements and volume change measurements were compared. A method has been presented that allows the shear modulus values to be correlated to the relevant stress level acting around the pressuremeter during the test. The values of shear modulus obtained with the cone- pressuremeter were compatible with those obtained from the self-boring pressuremeter. An assessment of chamber size effects yielded useful information regarding the applicability of test correlations derived from calibration chambers to field problems. An additional study identified experimentally the influence of length to diameter ratio on the pressuremeter pressure-expansion curve.

The quasi-static penetration of a cone penetrometer into clay can be formulated as a steady state problem by considering a steady flow of soil past a stationary cone. The soil velocities are estimated from the flow field of an inviscid fluid, and the incompressibility condition is achieved by adopting a stream function formulation. Emphasis is placed on obtaining an accurate velocity estimate and this is accomplished by a solution of the Navier-Stokes equations. The strain rates are evaluated from the flow field using a finite difference scheme. The clay is modelled as a homogeneous incompressible elastic-perfectly plastic material and the soil stresses are computed by integrating along streamlines from some initial stress state in the upstream region. These stresses do not in general obey the equilibrium equations, although one of the two equations can be satisfied by an appropriate choice of the mean stress. Several attempts have been made to use the remaining equilibrium equation to obtain an improved velocity estimate and three plausible iterative methods are detailed in this thesis. In a second study, a series of finite element calculations on the cone penetration problem is performed. In modelling the penetration process, the cone is introduced in a pre-formed hole and some initial stresses assumed in the soil, incremental displacements are then applied to the cone until a failure condition is reached. Although the equilibrium condition is satisfied very closely in the finite element calculations, it is extremely difficult to achieve a steady state solution. In a third series of computations, the stresses evaluated by the strain path method are used as the starting condition for the finite element analysis. This is believed to give the most realistic solution of the cone penetration problem because both the steady state and equilibrium conditions are approximately satisfied. Numerically derived cone factors are presented and these are found to depend on the rigidity index of the soil and the in situ stresses. The pore pressure distribution in the soil around the penetrometer is estimated using Henkel's empirical equation. The dissipation analysis is based on Terzaghi's uncoupled consolidation theory. The governing equation is formulated in the Alternating-Direction-Implicit finite difference scheme. This formulation is unconditionally stable and variable time steps are used to optimise the solution procedure. The dissipation curves are found to be significantly affected by the rigidity index of the soil and a dimensionless time factor is proposed to account for this effect.

The research was intended to enhance the understanding of penetrometer behaviour in normally consolidated clay. The effects of varying penetration rate and clay shear strength were studies and the distribution of pore pressures determined. The meet these objectives laboratory testing was undertaken. Penetration tests were to be performed in tanks of clay consolidated from slurry and maintained under known stresses. An initial series of tests examined the effect of stiff tank walls. These showed unexpectedly high radial boundary stresses were generated with tank to probe diameter ratios of 50:1. This finding dictated laboratory tests with small scale penetrometers in the largest practical size of tank. Field tests with small scale and full size penetrometers demonstrated an absence of scale effect in the penetrometer pore pressures and total stress data. Two consolidation tanks of 580mm diameter and one of 1000mm diameter were built with the facility for maintaining constant stresses on top of the sample during penetration. Piezocone penetrometers of 5cm2 and 1cm2 cross-section were built. Penetration tests were performed from 2cm/s to 3m/s with hydraulic insertion equipment. At lower rates the total cone resistance factor Nkt was shown to be 10.3±0.9 in normally consolidated kaolin. The corresponding pore pressure factor NΔu was 8.25±1.0 at the cone shoulder. A hundredfold increase in the penetration rate increased the Nkt factor by 40% but the NΔu factor was unchanged. Various subsidiary points emerged. The type of strength test used for comparison with penetrometer data is significant. Major strength reductions occur on sample depressurization. These were demonstrated with vane and triaxial tests. Baligh and Levadoux’s method for determining ch from pore pressure dissipation around penetrometers matched experimental data. Ratios of excess pore pressures on the cone face and shoulder show some promise in the evaluation of OCR.

An essential component for evaluating the performance of a mine site after its closure includes the tracking of water movement through mine waste such as tailings and overburden. A critical element of this evaluation is the measurement of the volume of water stored in the closure landform. The objective of this project was to design a time domain reflectometry (TDR) device that could be used to measure the volumetric water content of a soil profile to depths of 10 to 20 m. Upon completion of this project, the device will be integrated onto ConeTec’s cone penetration testing (CPT) shaft for initially monitoring Syncrude Canada Limited’s northeastern Alberta oil sands mine site. The objective of this project will be achieved through at least two phases of research and development; this thesis concentrates on the first phase. In this phase, research focused on prototype development through laboratory testing to determine appropriate TDR probe geometries and configurations that could be integrated onto a CPT shaft. Considerations also had to be made for protecting the integrity of the probe during field use and mitigating the effects of highly electrically conductive soils common in reclaimed mine sites. A number of different prototype designs were initially investigated in this research, leading to the development of a refined prototype for advanced testing. Testing for the project was carried out first in solutions of known dielectric constants and salinities, and then proceeded to soils with a range of known water contents and salinities. Good quality electrical connections were found to be crucial for generating waveforms that were easy to interpret; bad connections resulted in poor results in a number of cases. Decreased probe sensitivity was observed in response to increased rod embedment within the probe variants. A far greater decrease in sensitivity was seen in the results of the fully sheathed rods, although the sheathing was effective for extending the range of the probe in electrically conductive testing conditions. Despite poor results that were seen in some of the tests, overall the results were promising. In particular, results from the push-test showed that the probe was able to monitor changes in water content with depth.

In mass spectrometry an electrospray is commonly used as an ion source. At high sample flow rates a sheath co-flow of gas around the electrospray emitter is employed. The co-flow of gas reduces contamination and increases signal sensitivity in the mass spectrometer’s results. This work characterizes the operation of an electrospray with co-flowing air for various operating conditions. It is found that a co-flowing air has a negligible effect on droplet size for the spindle and cone jet modes while it only reduces the droplet size marginally in the unstable mode. In the high flow rate unstable mode, the addition of air seems to have no real effect on droplet size. In summary, the electrospray with co-flowing air produces a denser and more focused spray with similar droplet size and distribution than that of the un-nebulized spray. This explains why using co-flowing air in mass spectrometry applications improves the signal quality, since it allows for the focusing of droplets produced into the inlet and also aids in the breakup of larger droplets.

In mass spectrometry an electrospray is commonly used as an ion source. At high sample flow rates a sheath co-flow of gas around the electrospray emitter is employed. The co-flow of gas reduces contamination and increases signal sensitivity in the mass spectrometer’s results. This work characterizes the operation of an electrospray with co-flowing air for various operating conditions. It is found that a co-flowing air has a negligible effect on droplet size for the spindle and cone jet modes while it only reduces the droplet size marginally in the unstable mode. In the high flow rate unstable mode, the addition of air seems to have no real effect on droplet size. In summary, the electrospray with co-flowing air produces a denser and more focused spray with similar droplet size and distribution than that of the un-nebulized spray. This explains why using co-flowing air in mass spectrometry applications improves the signal quality, since it allows for the focusing of droplets produced into the inlet and also aids in the breakup of larger droplets.

This study assessed the accuracy and reliability of tooth length measurements through axial, coronal and sagittal serial slices of CBCT volumes; conventional panoramic radiographs; and CBCT panoramic reconstructions to that of a digital caliper gold standard. Samples consisted of maxillary premolars collected from patients requiring extractions for routine orthodontic treatment. Extracted teeth were measured directly with digital calipers and images were digitally measured in Dolphin 3D software. Analysis of CBCT serial slices resulted in highly accurate and reliable tooth length measurements for all slice orientations compared to the gold standard. Conventional panoramic radiographs were relatively inaccurate, overestimating tooth lengths by 29%, while CBCT panoramic reconstructions underestimated lengths by 4%. CBCT serial slice volume analysis provides clinicians with greater measurement confidence, while panoramic radiographs, produced either by conventional means or reconstructed from 3-D volumes should be considered less accurate and reliable for the detection of mild root resorption. / Medical Sciences - Orthodontics

The purpose of this research was to compare skeletal and dental changes assessed by digital volumetric images produced during and after rapid maxillary expansion (RME) between a bone-borne anchored expansion appliance and a conventional tooth-borne RME. Initial steps included the development of a methodology to analyze CBCT images. Reliability of traditional two dimensional (2D) cephalometric landmarks identified in CBCT images was explored, and new landmarks identifiable on the CBCT images were also evaluated. This methodology was later tested through a clinical trial with 62 patients where skeletal and dental changes found after maxillary expansion using either a bone-borne or tooth-borne maxillary expander and compared to a non-treated control group. The conclusions that were obtained from this thesis were that the NewTom 9” and 12” three dimensional (3D) images present a 1-to-1 ratio with real coordinates, linear and angular distances obtained by a coordinate measurement machine (CMM). Landmark intra- and inter-reliability (ICC) was high for all CBCT landmarks and for most of the 2D lateral cephalometric landmarks. Foramen Spinosum, foramen Ovale, foramen Rotundum and the Hypoglossal canal all provided excellent intra-observer reliability and accuracy. Midpoint between both foramen Spinosums (ELSA) presented a high intra-reliability and is an adequate landmark to be used as a reference point in 3D cephalometric analysis. ELSA, both AEM and DFM points presented a high intra-reliability when located on 3D images. Minor variations in location of these landmarks produced unacceptable uncertainty in coordinate system alignment. The potential error associated with location of distant landmarks is unacceptable for analysis of growth and treatment changes. Thus, an alternative is the use of vectors. Selection of landmarks for use in 3D image analysis should follow certain characteristics and modifications in their definitions should be applied. When measuring 3D maxillary complex structural changes during maxillary expansion treatments using CBCT, both tooth-anchored and bone-anchored expanders presented similar results. The greatest changes occurred in the transverse dimension while changes in the vertical and antero-posterior dimension were negligible. Dental expansion was also greater than skeletal expansion. Bone-anchored maxillary expanders can be considered as an alternative choice for tooth-anchored maxillary expanders. / Medical Sciences in Orthodontics

Cartilage tissue provides compressive resistance in diarthrodial joints, and has been shown to be regulated by mechanical signals, in particular with regard to production of extracellular matrix proteins. However, less is understood about how chondrocytes in regions not solely purposed to provide compressive resistance may also be affected by mechanical forces. The growth plate is a small layer of cartilage that functions to facilitate longitudinal growth of the long bones from in utero through post-adolescent development. The growth plate maintains distinct regions of chondrocytes at carefully regulated stages of endochondral ossification that are in part characterized by their morphology and differential responsiveness to vitamin D metabolites. Understanding if mechanical cues could be harnessed to accelerate or delay the process of endochondral ossification might be beneficial for optimizing tissue engineering of cartilage or osteochondral interfaces. This study focused on three aims to provide a basis for future work in this area: 1) Develop a cell line culture model useful for studying growth plate chondrocytes, 2) Determine the response of primary growth plate chondrocytes and the cell line model to fluid shear stress, and 3) determine if expression of integrin beta 1 is important for the observed responses to shear stress. The findings of this study suggest that inorganic phosphate can promote differentiation in coordination with the 24,25(OH)2D3 metabolite of vitamin D, and that fluid shear stress generally inhibits differentiation and proliferation of growth plate chondrocytes in part through an integrin beta 1 mediated pathway.