After water vapour, CO₂ is the most abundant gas associated with magmatic hydrothermal systems. The detection of anomalous soil temperature gradients, and/or a significant flux of magmatic volatiles, is commonly the only surface signature of an underlying high temperature reservoir. For both heat (as water vapour) and gas to ascend to the surface, structural permeability must exist, as the unmodified bulk permeability of reservoir rock is too low to generate the focussed fluid flow typical of magmatic hydrothermal systems. This thesis reports the investigation into the surface heat and mass flow of the Ohaaki hydrothermal field using detailed surface measurements of CO₂ flux and heat flow. Detailed surface measurements form the basis of geostatistical models that quantify and depict the spatial variability of surface heat and mass flow, across the surface of both major thermal areas, as high resolution pixel plots. These maps, in conjunction with earlier heat and mass flow studies, enable: (i) estimates of the pre-production and current CO₂ emissions and heat flow for the Ohaaki Field; (ii) interpretation of the shallow permeability structures governing fluid flow, and; (iii) the spatial relationships between pressure-induced ground subsidence and permeability. Heat flow and CO₂ flux surveys indicate that at Ohaaki the soil zone is the dominant (≥ 70% and up to 99%) pathway of heat and mass release to the atmosphere from the underlying hydrothermal reservoir. Modelling indicates that although the total surface heat and mass flow at Ohaaki is small, it is highly focused (i.e., high volume per unit area) relative to other fields within the Taupo Volcanic Zone (TVZ). Normalised CO₂ emissions are comparable to other volcanic and hydrothermal fields both regionally and globally. Despite 20 years of production, there is little difference between pre-production and current CO₂ emission rates. However, the similarity of CO₂ emission rates masks a 40% increase in CO₂ emissions from new areas of intense steaming ground that have developed in response to production of the field for electrical energy production. This increase in thermal ground emissions is offset by emission losses associated with the drying up of all steam heated pools and alkali-Cl outflows from the Ohaaki West (OHW) thermal area, in response to production-induced pressure decline. The location of surface thermal areas is governed by the occurrence of buried or partially emergent lava domes, whereas the magnitude of CO₂ flux, mass flow, and heat flow occurring within each thermal area is determined by the proximity of each dome (thermal areas) to major upflow zones. Buried or partially emergent silicic lava domes act as cross-stratal pathways for fluid flow, connecting the underlying reservoir to the surface, and bypassing several hundred metres of the poorly permeable Huka Falls Formation (HFF) caprock. For each dome complex the permeable structures governing fluid flow are varied. At Ohaaki West, thermal activity is controlled by a deep-rooted concentric fracture zone, developed during eruption of the Ohaaki Rhyolite dome. Within the steam-heated Ohaaki East (OHE) thermal area, flow is controlled by a high permeability fault damage zone (Broadlands Fault) developed within the apex of the Broadlands Dacite dome. Structures controlling alkali-Cl fluid flow at OHW also iii appear to control the occurrence and shape of major subsidence bowls (e.g., the Main Ohaaki Subsidence Bowl), the propagation of pressure decline to surface, and the development and localization of pore fluid drainage. Across the remainder of the Ohaaki field low amplitude ground subsidence is controlled by the extent of aquifer and aquitard units that underlie the HFF, and proximity to the margins of the hot water reservoir. The correlation between the extent of low amplitude ground subsidence and the margins of the field reflects the coupled relationship between the hot water reservoir and reservoir pressure. Only where thick vapour-phase zones buffer the vertical propagation of deep-seated pressure decline to the surface (i.e., OHE thermal area), is ground subsidence not correlated with subvertical structural permeability developed within the HFF. This thesis makes contributions to regional and global research on geothermal and hydrothermal systems by: (i) quantifying the origin, mass, and upward transport of magmatic carbon from geothermal reservoirs; (ii) assessing the changes to the natural surface heat and mass flow of the Ohaaki Field following 20 years of production; (iii) establishing the utility of surface CO₂ flux and heat flow surveys to identify major upflow zones, estimate minimum mass flow, and determine the enthalpy of reservoirs; (iv) providing insight into the hydrothermal, structural and lithological controls over hydrothermal fluid flow; (v) demonstrating the influence of extinct silicic lava domes as important structural elements in the localisation of hydrothermal fluid flow; (vi) identifying the hydrostructural controls governing the spatial variability in the magnitude of pressure-induced ground subsidence, from which predictive models of subsidence risk may be defined, and; (vii) developing new technologies and characterising methods used for detailed assessment of surface heat and mass flow.

The Skellefte ore district in northern Sweden is a Palaeoproterozoic volcanic arc and one of the most important ones hosting volcanogenic massive sulfide (VMS) deposits, producing mainly base metals and orogenic gold deposits. Due to high metal prices and increased difficulties in finding shallow deposits, the exploration for and exploitation of mineral resources is quickly being moved to greater depths. For this reason, a better understanding of the geological structures in 3D down to a few kilometers depth is required as a tool for ore targeting. As exploration and mining go deeper, it becomes more and more evident why a good understanding of geology in 3D at exploration depths, and even greater, is important to optimize both exploration and mining. Following a successful pilot 3D geological modeling project in the western part of the district, the Kristineberg mining area, a new project "VINNOVA 4D modeling of the Skellefte district" was launched in 2008, with the aim of improving the existing models, especially at shallow depth and extending the models to the central district. More than 100 km of reflection seismic (crooked) profiles were acquired, processed and interpreted in conjunction with geological observations and potential field data. Results were used to constrain the 3D geological model of the study area and provided new insights about the geology and mineral potential at depth. Results along the seismic profiles in the Kristineberg mining area proved the capability of the method for imaging reflections associated with mineralization zones in the area, and we could suggest that the Kristineberg mineralization and associated structures dip to the south down to at least a depth of about 2 km. In the central Skellefte area, we were able to correlate main reflections and diffractions with the major faults and shear zones. Cross-dip analysis, reflection modeling, pre-stack time migration, swath 3D processing and finite-difference seismic modeling allowed insights about the origin of some of the observed reflections and in defining the imaging challenges in the associated geological environments. / VINNOVA 4D modeling of the Skellefte district

Background: The incidence of injuries in rugby union has increased on both professional and amateur levels since the introduction of professionalism in 1995. Although rugby union is a body contact sport with an expected high injury rate, limited research has been done regarding the postural and biomechanical characteristics of the players and the effect these variables have on the incidence and nature of rugby union injuries. Large body size is a significant predictor of success in rugby union and the body mass and mesomorphy of players has increased over the last years. It has, however, not been thoroughly investigated whether changes in body composition have any effect on the incidence of rugby union injuries. Intrinsic risk factors that have been identified to contribute to rugby union injuries are Hyper-mobility of joints, lack of dynamic mobility and core stability, previous injuries, aerobic and anaerobic fitness as well as the personalities and characteristics of players which affect their on-field awareness. The findings of studies investigating the relation between player characteristics and rugby union injuries are inconsistent because of the differences in player characteristics under investigation and playing conditions, different research methodologies used as well as differences in the way injury is defined. Therefore, the need exists to determine the differences in the biomechanical, postural and anthropometrical characteristics of injured and uninjured rugby union players by making use of a prospective design and a standardized injury definition. Objectives: The objectives of this study were firstly, to determine the incidence and nature of injuries among U/21 rugby union players at the Rugby Institute (RI) of the North-West University (NWU) (South Africa) and secondly, to determine which of the selected biomechanical, postural and anthropometrical characteristics contributed to musculoskeletal injuries obtained during the first five months of the 2005 season. Method: s A prospective once-off subject availability study was performed that included forty-nine U/21-rugby union players of the RI of the NWU. Biomechanical, postural and anthropometrical assessments were performed on all subjects before the start of the 2005- season. All the injuries sustained during the first five months of the 2005 season were recorded by means of a validated rugby union injury report questionnaire. A stepwise discriminant analysis identified the independent variables that discriminated mostly between the players with and without injuries within the different body regions. Back-classification by means of the "Jack-knife method" determined whether the independent characteristics that were selected to contribute to injuries was valid and the effect size, I ("better than chance"), was then determined, with I > 0.3 accepted as practically significant. Results: A total of 66 injuries with an injury rate of 8.611000 training hours and 61.811000 game hours were reported. Severe injuries accounted for 53% of all injuries to forward players with the ankle being the most injured anatomical region. In the backline severe injuries accounted for 11% with the shoulder being the most injured region. The tackle was the phase of play in which most injuries occurred. The statistical analysis identified uneven hips, pronated feet, tight hamstrings, anatomical leg length differences, gait pronation and a tall stature to be practically significant predictors for lower extremity injuries (I>0.3). No practical significance was obtained for the selected biomechanical, postural and anthropometrical characteristics related to shoulder girdle as well as back or spine injuries. Conclusions: The conclusions that can be drawn from this study are that the injury incidence of rugby union players of the U/21-squad of the RI of the NWU is high in comparison with those of other club level players and that postural and biomechanical imbalances of the lower extremities may increase the risk for injury in this area. / Thesis (M.A. (Human Movement Science))--North-West University, Potchefstroom Campus, 2007.

At the frontal ridge near the base of the slope off Vancouver Island, wide-angle ocean bottom seismometer (OBS) data were acquired in summer 2005, in support of the Integrated Ocean Drilling Program (IODP) Expedition 311. Marine gas hydrate is present beneath the ridge based on the observation of the 'Bottom Simulating Reflector' (BSR) that is interpreted to coincide with the base of the methane hydrate stability zone. Hydrate was also observed in downhole logs and drilling by IODP. The BSR has been identified on single-channel seismic data at -250-260 m depth beneath the ridge crest and on its seaward slope. The OBS data have been analyzed with the objective of determining the velocity structure in the upper portion of the accretionary wedge especially the hydrate stability zone and underlying free gas. As identified by a clear refracted phase, the velocity structure above the BSR shows anomalous high velocities of about 1.95 (±0.5) km/s at shallow depths of 80 - 110 m. On vertical incidence data, high amplitude reflectors are observed near this depth. Below the BSR, the velocities increase to -2.4 km/s at sub-seafloor depths of about 600 m. A strong refracted phase with a velocity of 4.0 km/s is generated at a depth of about 1700 mbsf. Velocities from traveltime inversion of OBS data are in general agreement with the Integrated Ocean Drilling Program (IODP) X311 downhole sonic velocities. In particular, on the log data, a layer with low porosity and high velocities of 2.4 - 2.8 km/s was observed at depths of 50 - 75 m. This probably corresponds with the 1.95 km/s layer at depths of 80-110 m interpreted from the OBS data. The refraction data thus suggest that this high-velocity layer varies laterally through the frontal ridge region, out to distances of at least 4 km from the drillhole. BSR depths (250-280 m) estimated in the present work also agree with the IODP X311 depths. From the velocity structure, we can make estimates of hydrate concentration in a region close to the deformation front, where fluid flow velocities are expected to be large. The gas hydrates concentrations vary from -35% for the shallow phase to -22% for the layer above the BSR. The deep refracted phase with a velocity of 4.0 km/s at 1700 m depth indicates the presence of highly compacted accreted wedge sediments. On the SW side of the frontal ridge, a collapse structure is observed in newly acquired multi-beam bathymetry data from the University of Washington and in seismic reflection data. The BSR is present in the region surrounding the slump. There are only weak indications of its presence within the slide region. Since hydrates may prevent normal sediment compaction, their dissociation in sediment pores is thought to decrease seafloor strength, potentially facilitating submarine landslides on continental slopes. The head wall of the frontal ridge slide is -250 m high, extending close to the BSR depth, and the slump has eroded a -2.5 km long section into the ridge, along strike. Migrated seismic reflection data image a set of normal faults in the frontal ridge striking NE-SW, perpendicular to the strike of the ridge and the direction of plate convergence. These faults outcrop at the seafloor and can be traced from the surface through the sedimentary section to depths well below the BSR in some locations. Seafloors scarps show that fault seafloor displacements of -25 m to 75 m are generated. The two faults with the largest seafloor scarps bound the region of slope failure on the frontal ridge, suggesting that the lateral extent of slumping is fault-controlled. The triggering mechanism for the slope failure may have been a combination of various effects. The possible mechanisms explored include gas hydrate dissociation, high pore pressure fluid expulsion along the faults, and salinity elevation in faults which would inhibit the formation of gas hydrates along the faults. However, an earthquake may induce initial slope failure, which can not only start gas hydrate dissociation but also increase fluid expulsion and pore pressure.

This dissertation presents algorithms for achieving communication in the presence of adversarial attacks in large, decentralized, resource-constrained networks. We consider abstract single-hop communication settings where a set of senders 𝙎 wishes to directly communicate with a set of receivers 𝙍. These results are then extended to provide resource-efficient, multi-hop communication in wireless sensor networks (WSNs), where energy is critically scarce, and peer-to-peer (P2P) networks, where bandwidth and computational power are limited. Our algorithms are provably correct in the face of attacks by a computationally bounded adversary who seeks to disrupt communication between correct participants. The first major result in this dissertation addresses a general scenario involving single-hop communication in a time-slotted network where a single sender in 𝙎 wishes to transmit a message 𝘮 to a single receiver in 𝙍. The two players share a communication channel; however, there exists an adversary who aims to prevent the transmission of 𝘮 by periodically blocking this channel. There are costs to send, receive or block 𝘮 on the channel, and we ask: How much do the two players need to spend relative to the adversary in order to guarantee transmission of the message? This problem abstracts many types of conflict in information networks, and the associated costs represent an expenditure of network resources. We show that it is significantly more costly for the adversary to block 𝘮 than for the two players to achieve communication. Specifically, if the cost to send, receive and block 𝘮 in a slot are fixed constants, and the adversary spends a total of 𝘉 slots to try to block the message, then both the sender and receiver must be active in only O(𝘉ᵠ⁻¹ + 1) slots in expectation to transmit 𝘮, where φ = (1+ √5)/2 is the golden ratio. Surprisingly, this result holds even if (1) the value of 𝘉 is unknown to either player; (2) the adversary knows the algorithms of both players, but not their random bits; and (3) the adversary is able to launch attacks using total knowledge of past actions of both players. Finally, these results are applied to two concrete problems. First, we consider jamming attacks in WSNs and address the fundamental task of propagating 𝘮 from a single device to all others in a WSN in the presence of faults; this is the problem of reliable broadcast. Second, we examine how our algorithms can mitigate application-level distributed denial-of-service attacks in wired client-server scenarios. The second major result deals with a single-hop communication problem where now 𝙎 consists of multiple senders and there is still a single receiver who wishes to obtain a message 𝘮. However, many of the senders (strictly less than half) can be faulty, failing to send 𝘮 or sending incorrect messages. While the majority of the senders possess 𝘮, rather than listening to all of 𝙎 and majority filtering on the received data, we desire an algorithm that allows the single receiver to decide on 𝘮 in a more efficient manner. To investigate this scenario, we define and devise algorithms for a new data streaming problem called the Bad Santa problem which models the selection dilemma faced by the receiver. With our results for the Bad Santa problem, we consider the problem of energy-efficient reliable broadcast. All previous results on reliable broadcast require devices to spend significant time in the energy-expensive receiving state which is a critical problem in WSNs where devices are typically battery powered. In a popular WSN model, we give a reliable broadcast protocol that achieves optimal fault tolerance (i.e., tolerates the maximum number of faults in this WSN model) and improves over previous results by achieving an expected quadratic decrease in the cost to each device. For the case where the number of faults is within a (1-∊)-factor of the optimal fault tolerance, for any constant ∊>0, we give a reliable broadcast protocol that improves further by achieving an expected (roughly) exponential decrease in the cost to each device. The third and final major result of this dissertation addresses single-hop communication where 𝙎 and 𝙍 both consist of multiple peers that need to communicate in an attack-resistant P2P network. There are several analytical results on P2P networks that can tolerate an adversary who controls a large number of peers and uses them to disrupt network functionality. Unfortunately, in such systems, operations such as data retrieval and message sending incur significant communication costs. Here, we employ cryptographic techniques to define two protocols both of which are more efficient than existing solutions. For a network of 𝘯 peers, our first protocol is deterministic with O(log²𝘯) message complexity and our second protocol is randomized with expected O(log 𝘯) message complexity; both improve over all previous results. The hidden constants and setup costs for our protocols are small and no trusted third party is required. Finally, we present an analysis showing that our protocols are practical for deployment under significant churn and adversarial behaviour.

The recent earthquakes in Turkey have shown the poor seismic performance of reinforced concrete. This led to widespread utilization of several strengthening methods, each of which is convenient in different aspects. However, what is required to apply any of these methods is to evacuate the building in question since the interruptions are mostly within the building and to the structural members. This study proposes a method for external strengthening of typical five storey reinforced concrete buildings that represent the majority of the built environment in Turkey. The method suggests addition of shear walls, which are connected to each other by means of diaphragms on two floor levels, to the existing external columns at four corners of the building. The positive effect of shear walls in seismic performance is already known / however / basically, the aim of this study is to discuss the feasibility of the proposed method in terms of architectural viewpoint since the method unavoidably covers great modifications on the architectural form of the building. Hence, the research mostly explores whether it is possible to give the reinforced concrete residential buildings, which constitute the majority of the built environment especially after 1950s due to the unhealthy urbanization period in Turkey, a common characteristic appearance by means of external structural members. As a whole, proposing an external strengthening method that provides not to evacuate the space, the study searches to obtain a typical fa&ccedil / ade resemblance by means of additional structural members.

The Alpine Fault is the major structure of the Pacific-Australian plate boundary through New Zealand�s South Island. During dextral reverse fault slip, a <5 million year old, ~1 km thick mylonite zone has been exhumed in the hanging-wall, providing unique exposure of material deformed to very high strains at deep crustal levels under boundary conditions constrained by present-day plate motions. The purpose of this study was to investigate the fault zone rheology and mechanisms of strain localisation, to obtain further information about how the structural development of this shear zone relates to the kinematic and thermal boundary constraints, and to investigate the mechanisms by which the viscously deforming mylonite zone is linked to the brittle structure, that fails episodically causing large earthquakes. This study has focussed on the central section of the fault from Harihari to Fox Glacier. In this area, mylonites derived from a quartzofeldspathic Alpine Schist protolith are most common, but slivers of Western Province-derived footwall material, which can be differentiated using mineralogy and bulk rock geochemistry, were also incorporated into the fault zone. These footwall-derived mylonites are increasingly common towards the north. At amphibolite-facies conditions mylonitic deformation was localised to the mylonite and ultramylonite subzones of the schist-derived mylonites. Most deformation was accommodated by dislocation creep of quartz, which developed strong Y-maximum crystallographic preferred orientation (CPO) patterns by prism (a) dominant slip. Formation of this highly-oriented fabric would have led to significant geometric softening and enhanced strain localisation. During this high strain deformation, pre-existing Alpine Schist fabrics in polyphase rocks were reconstituted to relatively well-mixed, finer-grained aggregates. As a result of this fabric homogenisation, strong syn-mylonitic object lineations were not formed. Strain models show that weak lineations trending towards ~090� and kinematic directions indicated by asymmetric fabrics and CPO pattern symmetry could have formed during pure shear stretches up-dip of the fault of ~3.5, coupled with simple shear strains [greater than or equal to]30. The preferred estimate of simple:pure shear strain gives a kinematc vorticity number, W[k] [greater than or equal to]̲ 0.9997. Rapid exhumation due to fault slip resulted in advection of crustal isotherms. New thermobarometric and fluid inclusion analyses from fault zone materials allow the thermal gradient along an uplift path in the fault rocks to be more precisely defined than previously. Fluid inclusion data indicate temperatures of 325+̲15�C were experienced at depths of ~45 km, so that a high thermal gradient of ~75�C km⁻� is indicated in the near-surface. This gradient must fall off to [ less than approximately]l0�C km⁻� below the brittle-viscous transition since feldspar thermobarometry, Ti-inbiotite thermometry and the absence of prism(c)-slip quartz CPO fabrics indicate deformation temperatures did not exceed ~ 650�C at [greater than or equal to] 7.0-8.5�1.5 kbar, ie. 26-33 km depth. During exhumation, the strongly oriented quartzite fabrics were not favourably oriented for activation of the lower temperature basal(a) slip system, which should have dominated at depths [less than approximately]20 km. Quartz continued to deform by crystal-plastic mechanisms to shallow levels. However, pure dislocation creep of quartz was replaced by a frictional-viscous deformation mechanism of sliding on weak mica basal planes coupled with dislocation creep of quartz. Such frictional-viscous flow is particularly favoured during high-strain rate events as might be expected during rupture of the overlying brittle fault zone. Maximum flow stresses supported by this mechanism are ~65 Mpa, similar to those indicated by recrystallised grain size paleopiezometry of quartz (D>25[mu]m, indicating [Delta][sigma][max] ~55 MPa for most mylonites). It is likely that the preferentially oriented prism (a) slip system was activated during these events, so the Y-maximum CPO fabrics were preserved. Simple numerical models show that activation of this slip system is favoured over the basal (a) system, which has a lower critical resolved shear stress (CRSS) at low temperatures, for aggregates with strong Y-maximum orientations. Absence of pervasive crystal-plastic deformation of micas and feldspars during activation of this mechanism also resulted in preservation of mineral chemistries from the highest grades of mylonitic deformation (ie. amphibolite-facies). Retrograde, epidote-amphibolite to greenschist-facies mineral assemblages were pervasively developed in ultramylonites and cataclasites immediately adjacent to the fault core and in footwall-derived mylonites, perhaps during episodic transfer of this material into and subsequently out of the cooler footwall block. In the more distal protomylonites, retrograde assemblages were locally developed along shear bands that also accommodated most of the mylonitic deformation in these rocks. Ti-in-biotite thermometry suggests biotite in these shear bands equilibrated down to ~500+̲50�C, suggesting crystal-plastic deformation of this mineral continued to these temperatures. Crossed-girdle quartz CPO fabrics were formed in these protomylonites by basal (a) dominant slip, indicating a strongly oriented fabric had not previously formed at depth due to the relatively small strains, and that dislocation creep of quartz continued at depths [less than or equal to]20 km. Lineation orientations, CPO fabric symmetry and shear-band fabrics in these protomylonites are consistent with a smaller simple:pure shear strain ratio than that observed closer to the fault core (W[k] [greater than approximately] 0.98), but require a similar total pure shear component. Furthermore, they indicate an increase in the simple shear component with time, consistent with incorporation of new hanging-wall material into the fault zone. Pre-existing lineations were only slowly rotated into coincidence with the mylonitic simple shear direction in the shear bands since they lay close to the simple shear plane, and inherited orientations were not destroyed until large finite strains (<100) were achieved. As the fault rocks were exhumed through the brittle-viscous transition, they experienced localised brittle shear failures. These small-scale seismic events formed friction melts (ie. pseudotachylytes). The volume of pseudotachylyte produced is related to host rock mineralogy (more melt in host rocks containing hydrated minerals), and fabric (more melt in isotropic host rocks). Frictional melting also occurred within cataclastic hosts, indicating the cataclasites around the principal slip surface of the Alpine Fault were produced by multiple episodes of discrete shear rather than distributed cataclastic flow. Pseudotachylytes were also formed in the presence of fluids, suggesting relatively high fault gouge permeabilities were transiently attained, probably during large earthquakes. Frictional melting contributed to formation of phyllosilicate-rich fault gouges, weakening the brittle structure and promoting slip localisation. The location of faulting and pseudotachylyte formation, and the strength of the fault in the brittle regime were strongly influenced by cyclic hydrothermal cementation processes. A thermomechanical model of the central Alpine Fault zone has been defined using the results of this study. The mylonites represent a localised zone of high simple shear strain, embedded in a crustal block that underwent bulk pure shear. The boundaries of the simple shear zone moved into the surrounding material with time. This means that the exhumed sequence does not represent a simple 'time slice' illustrating progressive fault rock development during increasing simple shear strains. The deformation history of the mylonites at deep crustal P-T conditions had a profound influence on subsequent deformation mechanisms and fabric development during exhumation.

Electrified fencing is commonly used throughout the world to control animals with smaller and cheaper fence constructions than would otherwise be necessary with non-electrified wires. Typical installations have a long wire or wires starting from an electric fence energiser and then surrounding fields in various complex configurations. Faults on electric fences can be difficult to locate, with the average fence using tens of kilometres of wire. Basic fault-finding tools allow an operator to read the peak fence voltage, requiring the user to decide whether a fault is present and to randomly search for the source of the problem. The focus of this thesis is to develop a device that reduces the time to locate faults on a fence by providing more information about the location and nature of a fault, and will point in the direction of the fault.

Condition assessment of water distribution pipeline assets has been the focus of water authorities for many years. Transient response analysis, including Inverse Transient Analysis (ITA), provides a new potential method for performing specific nondestructive tests that gives much broader information regarding the condition of pipelines than existing technologies. The basic concept involves inducing a transient in a pipeline and measuring its pressure response. The pressure response is theoretically a function of the condition of the pipeline wall (which is the fundamental characteristic related to the propagation of a transient wavefront) and reflections and damping from any fault that may be present. If an accurate transient model of the pipeline under examination can be developed then it may then be possible to isolate particular parameters in it (relating to the wall thickness of the pipeline or faults such as blockages, air pockets and leaks) and fit these to give optimal matches between the model predicted and measured response of the pipeline. This process is often referred to as inverse analysis (and hence the derivation of the name Inverse Transient Analysis). While a significant amount of numerical and laboratory investigation has been carried out focussing on the use of ITA for leak detection, few field studies have been undertaken. The goal of this research is to determine whether transient response analysis and Inverse Transient Analysis (ITA) can be applied in field situations to provide useful information regarding the condition of pipeline walls and the presence of specific faults such as blockages, air pockets and leaks. Numerous field tests are conducted on large scale transmission pipelines, small scale distribution pipelines and a distribution network in order to obtain a view of the nature of the measured transient responses at each scale and to identify any common characteristics. The capacity of existing transient models to replicate the measured responses is then assessed and they are found to be generally incapable of replicating the field data. Given the physical complexity of field pipelines, and a number of complex phenomena that have been traditionally neglected, this result is not unexpected. The research proposes the development of transient models that can be calibrated to measured responses. These models incorporate mechanisms for including mechanical dispersion and damping and follow precedents developed in other fields of engineering in which damping of transient phenomena is significant. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1325427 / Thesis (Ph.D.) -- University of Adelaide, School of Civil and Environmental Engineering, 2008

Thesis (M. Sc.)--University of Canterbury, 2007. / Typescript (photocopy). "September 2007." Includes bibliographical references (leaves 83-89). Also available via the World Wide Web.