The numerical simulation of large-scale virtual acoustics and physical modelling synthesis is a computationally expensive process. Time stepping methods, such as finite difference time domain, can be used to simulate wave behaviour in models of three-dimensional room acoustics and virtual instruments. In the absence of any form of simplifying assumptions, and at high audio sample rates, this can lead to simulations that require many hours of computation on a standard Central Processing Unit (CPU). In recent years the video game industry has driven the development of Graphics Processing Units (GPUs) that are now capable of multi-teraflop performance using highly parallel architectures. Whilst these devices are primarily designed for graphics calculations, they can also be used for general purpose computing. This thesis explores the use of such hardware to accelerate simulations of three-dimensional acoustic wave propagation, and embedded systems that create physical models for the synthesis of sound. Test case simulations of virtual acoustics are used to compare the performance of workstation CPUs to that of Nvidia’s Tesla GPU hardware. Using representative multicore CPU benchmarks, such simulations can be accelerated in the order of 5X for single precision and 3X for double precision floating-point arithmetic. Optimisation strategies are examined for maximising GPU performance when using single devices, as well as for multiple device codes that can compute simulations using billions of grid points. This allows the simulation of room models of several thousand cubic metres at audio rates such as 44.1kHz, all within a useable time scale. The performance of alternative finite difference schemes is explored, as well as strategies for the efficient implementation of boundary conditions. Creating physical models of acoustic instruments requires embedded systems that often rely on sparse linear algebra operations. The performance efficiency of various sparse matrix storage formats is detailed in terms of the fundamental operations that are required to compute complex models, with an optimised storage system achieving substantial performance gains over more generalised formats. An integrated instrument model of the timpani drum is used to demonstrate the performance gains that are possible using the optimisation strategies developed through this thesis.

<p>The purpose of this thesis work was to develop an automatic fault detection system for surveillance of bearing temperature in hydropower turbines. The parameters used except the bearing temperature were cooling water temperature and cooling water flow. A simple static model based on data sampled every minute was developed to estimate the bearing temperature. Then a detector for detection of change in bearing temperature based on the CUSUM-algorithm was designed. Since the amount of data was very small the developed model was too uncertain to be used in a working system.</p><p>The designed fault detection system showed to work well for the available data. It is, however, recommended that the performance of the system should be evaluated using more data. Another model based on data sampled once every minute for at least a year has to be developed before the system can be fully evaluated. The results shown were:</p><p>• The fault detection system can discover fast and slow changes in bearing temperature.</p><p>• No false alarms were given for measuring faults and sensor faults of the types used in this thesis. If a measuring fault occurs for too long there will be an alarm.</p><p>The fault detection algorithm was also implemented in Delphi to be used in a working system over the Internet where for example trends and alarms will be presented.</p> / <p>Syftet med examensarbetet var att utveckla ett automatiskt feldetekteringssystem för övervakning av bärlagertemperaturen i vattenkraftturbiner. De ingående parametrarna förutom bärlagertemperaturen var kylvattentemperaturen och kylvattenflödet. En enkel statisk modell baserad på data samplat en gång per minut togs fram för att estimera bärlagertemperaturen. Därefter utvecklades en detektor för att upptäcka avvikelser i bärlagertemperaturen baserad på CUSUM-algoritmen. På grund av en för liten mängd data var den framtagna modellen alltför osäker för att kunna implementeras i ett fungerande system.</p><p>Det framtagna feldetekteringssystemet visade sig fungera bra för de data som fanns tillgängliga. Det är däremot rekommenderat att utvärdera systemets prestanda med längre dataserier. En ytterligare modell baserad på minutdata över ett år måste tas fram innan systemet kan fungera på riktigt. De resultat som erhölls var:</p><p>• Feldetekteringssystemet klarar av att upptäcka abrupta och långsamma avvikelser av bärlagertemperaturen.</p><p>• Inga falsklarm ges då det är enstaka mätfel eller givarfel av sådan typ som tagits upp i arbetet. Pågår ett mätfel alltför länge ges dock ett larm.</p><p>Feldetekteringsalgoritmen implementerades även i Delphi för att kunna användas i ett fungerande system över Internet där t.ex. trendkurvor och larmsignaler skall kunna presenteras.</p>

Early warning of slope instability will enable evacuation of vulnerable people and timely repair and maintenance of critical infrastructure. However, currently available warning systems are too expensive for wide-scale use or have technical limitations. The acoustic emission (AE) monitoring approach using active waveguides (i.e. a steel tube with granular backfill surround installed in a borehole through a slope), in conjunction with the Slope ALARMS AE measurement system, has the potential to be an affordable early warning system for slope instability. However, the challenge has been to develop strategies to interpret and quantify deformation behaviour from measured AE. The development of an approach to quantify slope deformation behaviour from measured AE will enable the AE monitoring system to provide early warning of slope instability through detecting, quantifying and communicating accelerations in slope movement. Field monitoring and full-scale physical modelling have been conducted to characterise the AE response from the system to both reactivated slope movements and first-time slope failure. Definitive field evidence has been obtained showing AE monitoring can measure slope movements and generated AE rates are proportional to slope displacement rates, which was confirmed through comparisons with both conventional inclinometer and continuous ShapeAccelArray deformation measurements. A field monitoring case study demonstrated that the AE approach can detect very slow slope movements of 0.075 mm/day. In addition, the concept of retrofitting inclinometer casings with active waveguides to convert the manually read instrument to a real-time monitoring system has been demonstrated using a field trial. Dynamic strain-controlled shear tests on active waveguide physical models demonstrated that AE monitoring can be used to quantify slope displacement rates, continuously and in real-time, with accuracy to within an order of magnitude. Large-scale first-time slope failure experiments allowed the AE response to slope failure to be characterised. AE was detected after shear deformations of less than a millimetre in previously un-sheared material, and AE rates increased proportionally with displacement rates as failure occurred. The AE rate-displacement rate relationship can be approximated as linear up to 100 mm/hour and shear surface deformations less than 10-20 mm. At greater velocities and larger deformations the gradient of the relationship progressively increases and is best represented using a polynomial. This is because complex pressure distributions develop along the active waveguide analogous to a laterally loaded pile, and the confining pressures increase. Variables that influence the AE rate-displacement rate relationship have been quantified using physical model experiments and empirical relationships. A framework has been developed to allow AE rate-displacement rate calibration relationships to be determined for any AE system installation. This provides a universal method that can be used by practitioners when installing AE systems, to calibrate them to deliver alarm statuses/warning levels that are related to slope displacement rates. Use of this framework has been demonstrated using a case study example, and decision making protocols have been suggested that use trends in alarms with time to trigger decisions, which could be to send an engineer to inspect the slope, manage traffic, or evacuate people.

Le contrôle de la qualité de l'eau est fondé naturellement et traditionnellement sur des mesures et des prélèvements in situ. Des images satellites étalonnées à partir des données mesurées in situ fournissent une information quantitative et continue sur le milieu aquatique et peuvent être employées pour estimer, avec une approximation raisonnable, les facteurs affectant la qualité de l’eau L’objectif de ce travail consiste à modéliser les propriétés optiques de l’eau de mer et les paramètres physico-chimiques qui caractérisent les eaux côtières. L'application est basée sur le développement d’un Système d’Information Marin caractérisant un système de gestion de base de données géoréférencié POlGIS dédié à la gestion de l'information marine dans le cas de contrôle, suivi et surveillance de la pollution. Nous présentons des modèles exprimant les variables indicatrices de la qualité des eaux du littoral Algérois et la réflectance calculée de chaque pixel à partir d’un modèle physique de correction radiométrique. Les mesures in- situ sont effectuées pour des zones de différentes qualités d’eaux et leurs réflectances sont calculées à partir des images satellites SPOT, Landsat TM, MSS, IRS1C et Seawifs Finalement, des modèles sont établies avec les réflectances permettent d’obtenir des images satellites indicatrices de la pollution et de la bathymétrie des zones côtières à partir du logiciel de traitement d’image PCSATWIN développé afin d’estimer pour chaque pixel le degré de pollution du milieu. / In order to protect the natural medium and to control the pollution caused by such rejects, it is necessary to achieve a continuous survey of the reject zones. The goal of this study is a developed a methodology for modelling pollution and bathymetry from the digital satellite images.Indeed, our objective consists of the development of a software POLGIS intended for the management of the marine databases for the control and the monitoring of the pollution Satellite imagery can be used to estimate, with a reasonable accuracy, the factors affecting the water quality .It has a great importance to achieve the necessary continuous monitoring of the relevant area with an overall analysis of its pollution. A modelling analysis between the pollution contents and the reflectance calculated by the satellite images allow us to transform rough images into images treated and combined using a software of satellite image processing PCSATWIN developed in this study. This complex phenomena us developed an analytic model of radiatif transfer simulation in water coupled to an atmospheric model in order to simulate measure by satellite. This direct model permits to follow the solar radiance in his trajectory Sun-Atmosphere - Sea - Depth of sea- sensor. The goal of this simulation is to show for every satellite of observation (Spot, Landsat MSS, TM) possibilities that can offer in domain of bathymetry.The reflectance coefficient is calculated from satellite image, the detection and the possible determination of the zones contaminated by pollution using the space techniques constitute an effective means to intervene in order to ensure the monitoring of the Algerian coasts. The analysis shows us that each sensor offers useful information and that the combination between these various informations makes it possible to propose a procedure of maps establishment that can be interpreted as pollution maps.

Pipeline ploughs are commonly used to bury offshore pipelines for their protection from loading by currents, damage from fishing trawler vessels and to provide thermal insulation to the line allowing the product to flow more efficiently. The rate of progress of pipeline ploughs in sand is complicated by a rate effect which causes the required tow force to increase drastically with velocity. In this research plough performance in sand is investigated by means of physical scale model tests. Scale model tests are the most practical method by which to conduct a parametric study on plough behaviour as full sized testing would be prohibitively expensive. Scale model tests also provide accurate control of sand conditions which allows investigation of the effect of soil parameters on plough behaviour. Model ploughs were manufactured at 50th, 25th and 10th scale so that scale effects could be explored. Each of the model ploughs had a detachable forecutter to allow its effect on plough performance to be observed. The forecutter was found to reduce the rate effect but increase the non-velocity dependant resistance of the plough. Ploughing tests were conducted at various relative densities in three sands of different permeability. The effects of ploughing rate on model plough behaviour under these various conditions was explored using an instrumented model plough, with particular attention paid to the resulting tow force. Results from the model ploughing tests were interpreted to determine the effect of permeability, relative density and plough depth on the tow forces generated during ploughing. The rate effect was found to increase strongly with reduction in permeability of the sand. Increasing the relative density of the sand was found to increase the rate effect but had little influence on the passive resistance of the plough. The test results were compared to an empirical model developed by Cathie and Wintgens (2001). New coefficients (Cw, Cs and Cd) have been proposed and therefore design procedures modified which may allow trenching contractors to make better predictions of plough performance in sands.

The purpose of this thesis work was to develop an automatic fault detection system for surveillance of bearing temperature in hydropower turbines. The parameters used except the bearing temperature were cooling water temperature and cooling water flow. A simple static model based on data sampled every minute was developed to estimate the bearing temperature. Then a detector for detection of change in bearing temperature based on the CUSUM-algorithm was designed. Since the amount of data was very small the developed model was too uncertain to be used in a working system. The designed fault detection system showed to work well for the available data. It is, however, recommended that the performance of the system should be evaluated using more data. Another model based on data sampled once every minute for at least a year has to be developed before the system can be fully evaluated. The results shown were: • The fault detection system can discover fast and slow changes in bearing temperature. • No false alarms were given for measuring faults and sensor faults of the types used in this thesis. If a measuring fault occurs for too long there will be an alarm. The fault detection algorithm was also implemented in Delphi to be used in a working system over the Internet where for example trends and alarms will be presented. / Syftet med examensarbetet var att utveckla ett automatiskt feldetekteringssystem för övervakning av bärlagertemperaturen i vattenkraftturbiner. De ingående parametrarna förutom bärlagertemperaturen var kylvattentemperaturen och kylvattenflödet. En enkel statisk modell baserad på data samplat en gång per minut togs fram för att estimera bärlagertemperaturen. Därefter utvecklades en detektor för att upptäcka avvikelser i bärlagertemperaturen baserad på CUSUM-algoritmen. På grund av en för liten mängd data var den framtagna modellen alltför osäker för att kunna implementeras i ett fungerande system. Det framtagna feldetekteringssystemet visade sig fungera bra för de data som fanns tillgängliga. Det är däremot rekommenderat att utvärdera systemets prestanda med längre dataserier. En ytterligare modell baserad på minutdata över ett år måste tas fram innan systemet kan fungera på riktigt. De resultat som erhölls var: • Feldetekteringssystemet klarar av att upptäcka abrupta och långsamma avvikelser av bärlagertemperaturen. • Inga falsklarm ges då det är enstaka mätfel eller givarfel av sådan typ som tagits upp i arbetet. Pågår ett mätfel alltför länge ges dock ett larm. Feldetekteringsalgoritmen implementerades även i Delphi för att kunna användas i ett fungerande system över Internet där t.ex. trendkurvor och larmsignaler skall kunna presenteras.

<p>This thesis work aimed at increasing the knowledge regarding phenomena occurring when gas is injected using a top-blown lance on to a bath. All results are based on physical modeling studies carried out both using low and high gas flow rates and nozzle diameters ranging from 0.8 mm to 3.0 mm. At the low gas flow rates, the penetration depth in the bath was studied. The experiments focused on studying the effect of nozzle diameter, lance height and gas flow rate on the penetration depth. It was found that the penetration depth increases with decreasing nozzle diameter, decreasing lance height and with increasing gas flow rate. The results were also compared with previous work. More specifically, it was studied how the previous published empirical relationships fitted the current experimental data. It was found that the relationships of Banks [1], Davenport [2], Chatterjee [3] and Qian [4] agreed well with the experimental data of this investigation for nozzle diameters of 2.0 mm and 3.0 mm. However, for smaller nozzle diameters there were considerable deviations. Therefore, a new correlation heuristically derived from energy conservation consideration was suggested and showed better agreement for small nozzle diameters.</p><p>The experiments carried out at higher gas flow rates focused on the study of swirl motion. The effects of nozzle diameter, lance height, gas flow rate and aspect ratio on the swirl motion were investigated. The amplitude and period of the swirl as well as the starting time and the damping time of the swirl were determined. The amplitude was found to increase with an increased nozzle diameter and gas flow rate, while the period had a constant value of about 0.5 s for all nozzle diameters, gas flow rates and lance heights. The starting time for the swirl motion was found to decrease with an increased gas flow, while the damping time was found to be independent of gas flow rate, nozzle diameter, lance height and ratio of depth to diameter.</p>

Muskeg or peat deposits cover large areas in northern Manitoba. Test sections of a newly constructed highway on peat were instrumented to investigate their performance and to develop more economical means of construction method. Test Section ‘A’ was constructed with geotextile base layer while Section ‘B’ was with geotextile and corduroys (timber logs). The test sections were constructed during winter for ease in mobilizing construction equipment at the site when the ground was frozen and were instrumented to observe its behaviour and performance. Settlements were measured using monitoring plates and pins. Ground temperatures were measured using thermistors. Porewater pressures were measured using vibrating wire piezometers. Peat in the study area has an average thickness of 4m, with the upper layer classified as fibrous and the lower layer as amorphous with strong to complete decomposition. Standard laboratory tests were conducted on bored samples from the site. Hydraulic conductivity tests were carried out at different vertical pressures to determine its permeability. Thermal conductivity was determined at frozen and unfrozen state of peat. Conventional incremental oedometer tests were conducted to determine the compressibility parameters and secondary compression indices of the peat layers. Constant-rate-of-strain (CRS) tests were also performed to supplement the results obtained from the conventional method. Isotropically-Consolidated Undrained (CIŪ) triaxial tests were carried out to determine the shear strength of peat. A commercially-available computer program was used in the numerical modelling to simulate the field performance of the instrumented sections. The results from numerical modelling were reasonably close to the measured values in the field. Laboratory-scale physical modelling was undertaken to understand further the operating mechanisms involved in the performance of the two test sections under a more controlled environment. Artificial transparent clay that has similar deformation properties with most of the natural clays and peats was used as foundation material. It allows determination of spatial deformations beneath the embankment using Particle Image Velocimetry (PIV) technique. The load-settlement behaviour in the field was also reasonably simulated in the laboratory-scaled physical model. Deformation patterns from PIV indicate that embankment with geotextile layer and corduroy has smaller settlements and lateral movements in the foundation compared to that of the embankment with only geotextile layer.

Element test results reported in the literature under both triaxial and plane strain conditions indicate that loose saturated granular specimens can experience softening instability at stress ratios lower than what might otherwise be expected given the critical state friction angle of the soil. The region of potential softening instability in stress-space is often explained using the framework of the instability line. This phenomenon is particularly relevant to shallow slopes of 1 to 2 m depth. However, the practical realities of sample preparation for triaxial testing make performing tests below 20 to 30 kPa of confining stress exceptionally difficult. In this thesis, the development of a centrifuge tilt-table test device is described which aims to test the behaviour of loose granular slopes under stress paths of increasing slope inclination or increasing pore water pressure. A system of instrumentation including pore pressure transducers, inclinometers, displacement transducers, and high-resolution cameras was designed to monitor the behaviour of the slope model. The development of a system to provide a controlled groundwater level within the slope model proved to be particularly challenging. The results of two competing design concepts are presented for the water boundary condition and discussed. The centrifuge tilt-table is used to compare the physical response of a slope to the behaviour predicted by the infinite slope and softening instability models using scale model centrifuge testing. If softening instability is a rigorous concept, it should be the primary observed failure mechanism as it will occur at a stress state below the failure line. Tests were performed on loose Ottawa F110 sand at 1g, 20g and 40g and 60g. Deviatoric strain-softening was observed in loose dry sand. The softening instability event resulted in a rapid increase in shear strain at constant shear stress while the soil was at a stress state below the failure envelope. Any soil that can experience softening instability (i.e. granular, loose, saturated, and behaves undrained) will undergo two failures: one caused by deviatoric strain-softening (softening instability) and a second caused by shear failure at a larger slope angle. / Thesis (Master, Civil Engineering) -- Queen's University, 2014-04-29 22:01:36.786

The exchange of mass (gases, water & salts) between the oceans and the atmosphere is vital to the maintenance of life on earth. At high wind velocities most of this exchange is attributable to breaking wave entrained air bubbles. A vertical supported planar plunging jet experiment was used to model the entrainment process. The bubbles were detected with a dual tip conductivity probe and a video camera. At plunging jet velocities below 1.0m/s there is no bubble entrainment. This inception velocity appears to have a Froude and Weber number scaling for large rough turbulent jets. At jet velocities up to 5m/s air appeared to be entrained via intermittent air cavities at the jet - plunge pool intersection. The entrained air packets subsequently break in the two phase free shear layer under the entrainment point. At higher jet velocities there may be partial penetration of the aerated jet surface via pulsating induction cavities plus air entrainment via jet self aeration before impact. Plunging jet air flow data displays the different types of entrainment mechanisms. Mono-phase diffusion models can be successfully adapted to describe the shear layer developing zone. The diffusion of the air bubbles is approximately a Gaussian self similar process. The mean bubble velocity profiles can be modelled using the Goertler Error function or Hyperbolic Tangent models. The bubble spectra is approximately Lognormal with a geometric mean diameter of 1.0-2.0mm for a range of jet velocities. A bubble Weber number is found to model the maximum bubble size of approximately 10mm diameter. An original adaptation of the potential flow solution for the vortex sheet is shown to be a simple and reasonably accurate finite amplitude model for water surface gravity waves, especially in deep water. This model has some interesting features, such as both vertical and horizontal asymmetry and standing wave water profile modelling. A simple and possibly insightful model of wave growth due to the wind is introduced, using a constant sea surface Reynolds number U*.sqrt(L.F)/Gamma , where U* = wind friction velocity, L = wavelength, F = fetch, and Gamma = wave field vortex circulation per wavelength. The results may have application in the modelling of air - sea gas exchanges, predicting breaking wave forces on structures and the use of the planar plunging jet as an aeration device in industry.