A Barkhausen noise (BN) testing system was developed for the non-destructive evaluation (NDE) of residual stresses in CANDU reactor feeder pipes. The system consists of a four-channel arbitrary waveform flux control system (FCS), and the spring-loaded tetrapole prototype (SL4P) BN probe. The combination of the FCS and SL4P was shown to provide repeatable BN measurements on feeder pipe samples, with variations in air gaps between the SL4P poles and the sample from 0.43 mm to 1.29 mm, and typical pickup coil coupling uncertainties for the total BN energy from ±2% to ±7%. Precision for elastic strain estimation in feeder pipes was found to be between ±7 MPa and ±9 MPa in tension, depending on the excitation field configuration, and negligible in compression. Modelling of the BN penetration depth as a function of the excitation field was used to estimate the BN penetration depth between 5 μm at 300 kHz to a maximum of 500 μm at 3 kHz. The modelling, engineering, and procedures developed for this BN testing system provide an improved basis for the future advancement of BN testing, and ferromagnetic NDE in general. / Thesis (Ph.D, Physics, Engineering Physics and Astronomy) -- Queen's University, 2009-07-22 15:34:28.967

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The syntheses, structures, and magnetic properties of a series of di/trivalent hydridotris(3,5-dimethylpyrazol-1-yl)borate (Tp*) cyanomanganates were investigated. Treatment of manganese(III)acetylacetonate with KTp* followed by tetra(ethyl)- ammonium cyanide affords [NEt4][(Tp*)MnII(acac)(CN)] (1). Attempts to oxidize 1 with iodine affords {(Tp*)MnII(κ2O-acac-CN)}n (7); a minor complex {[NEt4][(Tp*)MnII(κ2O-acac-3-CN)]2(µ-CN) (8) was also isolated. The manganese(II) complex [NEt4][(Tp*)MnII(κ2O-acac-3-CN)(κ1N -3-NC-acac)] (2) was obtained via treatment of Mn(3-acacCN)3 with KTp* and [NEt4]CN. [NEt4]2[MnII(CN)4] (3) was prepared via treatment of Mn(OTf)2 with excess [NEt4]CN. [NEt4][(Tp*)MnIII(CN)3] (4), is prepared via treatment of 4 with Mn(3-acacCN)3, KTp* and excess [NEt4]CN. [PPN][(Tp*)MnIII(CN)3] (5) is obtained via treatment of [PPN]3[MnII(CN)6] with (Tp*)SnBu2Cl. Combination of 4 with [MnII(bipy)2(OH2)2][OTf]2 afforded a tetranuclear rectangular cluster {MnIII 2MnII 2} (9). At low temperature, {MnIII2NiII2} (10) was prepared via treatment of 4 and [Ni(II)(bipy)2(H2O)2][OTf]2. Treatment of 4 with [CoII(bipy)2(OH2)2][OTf]2 at low temperature failed to give the desired {MnIII2CoII2} complex. Magnetic measurements indicate that 1, 2, and 7 contain high-spin isotropic MnII with no long-range magnetic order observed for 7 (T > 2 K); 4 contains low-spin MnIII that likely adopt an isotropic 3A2 spin ground state. Surprisingly 9 and 10 do not exhibit slow relaxation of the magnetization (for T > 1.8 K) despite the presence of significant molecular anisotropy.

The Forsmark area, the main study area in this thesis, is located about 140 km north of Stockholm, central Sweden. It belongs to the Paleoproterozoic Svecokarelian orogen and contains several major ductile and brittle deformation zones including the Forsmark, Eckarfjärden and Singö zones. The bedrock between these zones, in general is less deformed and considered suitable for a nuclear waste repository. While several site investigations have already been carried out in the area, this thesis focuses primarily on (i) re-processing some of the existing reflection seismic lines to improve imaging of deeper structures, (ii) acquiring and processing high-resolution reflection and refraction data for better characterization of the near surface geology for the planning of a new access ramp, (iii) studying possible seismic anisotropy from active sources recorded onto sparse three-component receivers and multi-offset-azimuth vertical seismic profiling data (VSP). Reflection seismic surveys are an important component of these investigations. The re-processing helped in improving the deeper parts (1-5 km) of the seismic images and allowing three major deeper reflections to be better characterized, one of which is sub-horizontal while the other two are dipping moderately. These reflections were attributed to originate from either dolerite sills or brittle fault systems. First break traveltime tomography allowed delineating an undulating bedrock-surface topography, which is typical in the Forsmark area. Shallow reflections imaged in 3D, thanks to the acquisition design were compared with existing borehole data and explained by fractured or weak zones in the bedrock. The analysis of seismic anisotropy indicates the presence of shear-wave splitting due to transverse isotropy with a vertical symmetry axis in the uppermost hundreds of meters of crust. Open fractures and joints were interpreted to be responsible for the large delays observed between the transverse and radial components of the shear-wave arrivals, both on surface and VSP data.

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Geotechnical engineering design has relied upon deterministic methods of analysis whereby values for analysis parameters and conditions are selected subjectively based on judgment with the intent of providing acceptable margins of safety. The objective of this research was to improve the use of probabilistic slope stability analysis in practice so that the design of slopes can be made on a consistent and probabilistic basis. The current research involved the development of a methodology for the measurement and modeling of the anisotropic autocorrelation distance of cohesive soils, which was demonstrated at Dyke 17 West of the McArthur Falls Generating Station. In-situ testing using the piezocone and laboratory testing was conducted to characterize the spatial variability of the effective-shear strength envelope. Vertical (down-hole) and horizontal (cross-hole) geostatistical analysis was conducted to assess the anisotropy of the semivariogram. The investigation identified that heterogeneous inclusions had significant impacts on the results, but that simplistic (visual) identification and filtering procedures were adequate. The effective-stress shear strength envelope was statistically characterized as a random field, which was simulated as a first-order Markov process using customized add-in functions in a limit-equilibrium slope stability analysis. The analysis accounts for the spatial variability of shear strength and is capable of simulating both isotropic and anisotropic autocorrelation functions. The study showed that the critical slip surface geometry and the probability of failure can be significantly different when the anisotropy of spatial correlation is accounted for. The study also showed that neglecting spatial correlation may over-estimate the probability of failure, however this finding was noted to be likely case-specific. The primary conclusion of the study was that appropriate representation of spatial correlation is essential to calculating the probability of failure. Finally, convergence of the probabilistic simulation was evaluated using bootstrapping of the simulated factor of safety distribution to assess the standard error in the mean factor of safety, standard deviation of factor of safety and the probability of failure. A convergence criterion based on the percentage standard error in the probability of failure was proposed and used to define the number of Monte-Carlo iterations required.

The demonstration of an electrically pumped organic laser remains a major issue of organic optoelectronics for several decades. This goal requires an improved device configuration so as to reduce losses which are intrinsically higher under electrical excitation compared to optical pumping. Moreover a systematic investigation of the material properties is still missing and should lead to a reliable estimate of the lasing threshold under optical pumping, and then to a lower limit for electrical pumping. In this thesis we addressed the issue of gain and polarization properties of organic materials in the case of dye-doped polymer thin films. The originality of this work lies in the study of materials via the features of dielectric micro-lasers, allowing to investigate the issues of gain and mode coupling and the physics of open systems. We propose a quantitative description of amplification in organic materials. The "gain-loss-threshold" relation was developed and demonstrated for a Fabry-Perot type cavity, opening the way to study both amplification in organic materials and light out-coupling in dielectric micro-cavities via the lasing threshold. Within this context, different cavity shapes were studied, for instance squares, where light out-coupling takes place by diffraction at dielectric corners. We evidence that polarization properties of such lasing system originate from the intrinsic fluorescence anisotropy of dyes, which required to develop a specific anisotropic model going beyond the existing theory. We also investigated the role of the cavity geometry on the polarization states of the micro-lasers and proposed different ways to influence these features.

Aquifer storage and recovery (ASR) is a particular scheme of artificial recharge of groundwater by injecting fresh water into aquifers and subsequently recovering the stored water during times of peak demand or extended drought. In the era of combating climate change, ASR, as an effective means for water reuse and sustainable management of water resources in concert with the natural environment, represents a huge opportunity for climate change adaptation to mitigate water availability stress.The success of an ASR scheme is quantified by the recovery efficiency (RE), defined as the volume of stored water that can be recovered for supply purposes divided by the total volume injected. It is not uncommon that RE may be significantly lower than 100% because of the water quality changes as a consequence of the mixing between the injected water and native groundwater and the interaction between injected water and soil. Thus, the key of a successful ASR scheme is (1) to select appropriate aquifers and (2) to design optimal operational processes to build up a bubble of injected water with minimized negative impact from such mixing and interaction. To achieve this, this thesis develops an integrated knowledge base with sound interdisciplinary science and understanding of the mixing processes under operational ASR management in aquifers with various hydrogeological conditions. Analytical and numerical modeling are conducted to improve the scientific understanding of mixing processes involved in ASR schemes and to provide specific technical guidance for improving ASR efficiency under complex hydrogeological conditions. (1) An efficient approach is developed to analytically evaluate solute transport in a horizontal radial flow field with a multistep pumping and examine the ASR performance in homogeneous, isotropic aquifer with advective and dispersive transport processes. (2) Numerical and analytical studies are conducted to investigate the efficiency of an ASR system in dual-domain aquifers with mass transfer limitations under various hydrogeological and operational conditions. Simple and effective relationships between transport parameters and ASR operational parameters are derived to quantify the effectiveness and ascertain the potential of ASR systems with mass transfer limitations.(3) Effects of hydrogeological and operational parameters on ASR efficiency are assessed in homogeneous/stratified, isotropic/anisotropic coastal aquifers. Effects of transverse dispersion are particularly investigated in such aquifers.(4) Finally, we test and study an innovative ASR scheme for improving the RE in brackish aquifers: injection through a fully-penetrated well and recovery through a partially-penetrated well.