Yes / This paper describes an automated event detection and location system for water distribution pipelines which is based upon low-cost sensor technology and signature analysis by an Artificial Neural Network (ANN). The development of a low cost failure sensor which measures the opacity or cloudiness of the local water flow has been designed, developed and validated, and an ANN based system is then described which uses time series data produced by sensors to construct an empirical model for time series prediction and classification of events. These two components have been installed, tested and verified in an experimental site in a UK water distribution system. Verification of the system has been achieved from a series of simulated burst trials which have provided real data sets. It is concluded that the system has potential in water distribution network management.

<p>The report begins with a general inventory of possible technical faults in a hydropower plant and of possible fault indicating measurements. Then an investigation is made concerning a few different faults. Based on this investigation a choice on seal box condition and water leakage is made as problem for a more thorough examination, in which it is concluded that the turbine water leakage is larger when the turbine is put into operation. The examination ultimately results in a computer alarm for faults related to the seal box. Finally a few things are mentioned about flow measurement and pressure measurement in relation to the project as a whole.</p> / <p>Rapporten inleds med en övergripande sammanställning av möjliga tekniska fel i en vattenkraftstation och av möjliga felindikerande mätningar. Därefter görs en probleminventering av ett antal olika fel. Baserat på denna inventering väljes sedan tätningsboxkondition och läckvatten som problem för en mer ingående undersökning, vid vilken det konstateras att turbinvattenläckaget är större när turbinen är i drift. Undersökningen utmynnar sedan i ett datalarm för fel relaterade till tätningsboxar. Slutligen nämns något om flödesmätning och tryckmätning i relation till projektet i sin helhet.</p>

The purpose of this work is to contribute to a process formaking buildings with good function and to avoid prematurefaults. The design, construction and installation of low-slopedroofs are important parts of creating a durable building. Mostof the leakages in low-sloped roofs occur where materials withdifferent thermomechanical properties are joined together. Withbetter knowledge about these joints, the expected service lifecould better be estimated. Common roofing materials onlow-sloped roofs are roof membranes. To avoid damages and to minimise energy consumption thedetection of air and water leaks is essential. It can bedifficult to localise a leak in e.g. a roof since water canflow far within the construction. Leakage detection can beapplied both as a quality assurance method after installationof low-sloped roofs and as field inspection methods. Theleakage detection can also be extended to terrace slabs and thewhole building envelope. To investigate the strength of jointsbetween sheet metaland roofing membranes, several small-scale tests and somelarge-scale tests were performed. The test methods weredeveloped to match the loads that can be expected on this kindof joints. A number of water leak-detection methods were evaluatedthrough application on test roofs. Some of the methods todetect leaks on low-sloped roofs can also be used to detect airleakage in other parts of the building envelope. To develop andevaluate air leak-detection procedures, selected methods wereused in two case studies. The circumstances regarding welding of the material jointswere found to have great impact on the strength. The roofshould be designed so no long-term strain will appear since acomparatively low stress may damage the joint over time. The performance of the leak-detection methods depends on theroofing material. All methods tested were an improvementcompared to visual inspections. Different recommendedapproaches for leakage detection and quality control is given.The case studies show that air leakage detection could beperformed with good accuracy. The potential difference methodcould without doubt be a tool for leakage localisation inwaterproofing layers both on roofs and in terrace slabs. <b>Keywords:</b>Roofing, roof membrane, durability,waterproofing, leakage, wind-load, non-destructive testing,NDT, BSL4, BSL3, air leakage, building envelope

Over the last four decades the integrated circuit industry has evolved in a tremendous pace. This success has been driven by the scaling of device sizes leading to higher and higher integration capability, which have enabled more functionality and higher performance. The impressive evolution of modern high-performance microprocessors have resulted in chips with over a billion transistors as well as multi-GHz clock frequencies. As the silicon integrated circuit industry moves further into the nanometer regime, scaling of device sizes is still predicted to continue at least into the near future. However, there are a number of challenges to overcome to be able to continue the increase of integration at the same pace. Three of the major challenges are increasing power dissipation due to clocking of synchronous circuit, increasing leakage currents causing growing static power dissipation and reduced circuit robustness, and finally increasing spread in circuit parameters due to physical limitations in the manufacturing process. This thesis presents a number of circuit techniques that aims to help in all three of the mentioned challenges.Power dissipation related to the clock generation and distribution is identified as the dominating contributor of the total active power dissipation for multi-GHz systems. As the complexity and size of synchronous systems continues to increase, clock power will also increase. This makes novel power reduction techniques absolutely crucial in future VLSI design. In this thesis an energy recovering clocking technique aimed at reducing the total chip clock power is presented. Based on theoretical analysis the technique is shown to enable considerable clock power savings. Moreover, the impact of the proposed technique on conventional flip-flop topologies is studied. Measurements on an experimental chip design proves the technique, and shows more than 56% lower clock power compared to conventional clock distribution techniques at clock frequencies up to 1.76 GHz.Static leakage power dissipation is a considerable contributor to the total power dissipation. This power is dissipated even for circuits that are idle and not contributing to the operation. Hence, with increasing number of transistors on each chip, circuit techniques which reduce the static leakage currents are necessary. In this thesis a technique is discussed which reduces the static leakage current in a microcode ROM resulting in 30% reduction of the leakage power with no area or performance penalty.Apart from increasing static power dissipation the increasing leakage currents also impact the robustness constraints of the circuits. This is important for regenerative circuits like flip-flops and latches where a changed state due to leakage will lead to loss of functionality. This is a serious issue especially for high-performance dynamic circuits, which are attractive in order to limit the clock load in the design. However, with the increasing leakage the robustness of dynamic circuits reduces dramatically. To improve the leakage robustness for sub-90 nm low clock load dynamic flip-flops, a novel keeper technique is proposed. The proposed keeper utilizes a scalable and simple leakage compensation technique, which is implemented on a reconfigurable flip-flop. At normal clock frequencies the flip-flop is configured in dynamic mode, and reduces the clock power by 25% due to the lower clock load. During any low-frequency operation, the flip-flop is configured as a static flip-flop retaining full functional robustness.As scaling continues further towards the fundamental atomistic limits, several challenges arise for continuing industrial device integration. Large inaccuracies in lithography process, impurities in manufacturing, and reduced control of dopant levels during implantation all cause increasing statistical spread of performance, power, and robustness of the devices. In order to compensate the impact of the increasingly large process variations on latches and flip-flops, a reconfigurable keeper technique is presented in this thesis. In contrast to the traditional design for worst-case process corners, a variable keeper circuit is utilized. The proposed reconfigurable keeper preserves the robustness of storage nodes across the process corners without degrading the overall chip performance.

The report begins with a general inventory of possible technical faults in a hydropower plant and of possible fault indicating measurements. Then an investigation is made concerning a few different faults. Based on this investigation a choice on seal box condition and water leakage is made as problem for a more thorough examination, in which it is concluded that the turbine water leakage is larger when the turbine is put into operation. The examination ultimately results in a computer alarm for faults related to the seal box. Finally a few things are mentioned about flow measurement and pressure measurement in relation to the project as a whole. / Rapporten inleds med en övergripande sammanställning av möjliga tekniska fel i en vattenkraftstation och av möjliga felindikerande mätningar. Därefter görs en probleminventering av ett antal olika fel. Baserat på denna inventering väljes sedan tätningsboxkondition och läckvatten som problem för en mer ingående undersökning, vid vilken det konstateras att turbinvattenläckaget är större när turbinen är i drift. Undersökningen utmynnar sedan i ett datalarm för fel relaterade till tätningsboxar. Slutligen nämns något om flödesmätning och tryckmätning i relation till projektet i sin helhet.

<p>The purpose of this work is to contribute to a process formaking buildings with good function and to avoid prematurefaults.</p><p>The design, construction and installation of low-slopedroofs are important parts of creating a durable building. Mostof the leakages in low-sloped roofs occur where materials withdifferent thermomechanical properties are joined together. Withbetter knowledge about these joints, the expected service lifecould better be estimated. Common roofing materials onlow-sloped roofs are roof membranes.</p><p>To avoid damages and to minimise energy consumption thedetection of air and water leaks is essential. It can bedifficult to localise a leak in e.g. a roof since water canflow far within the construction. Leakage detection can beapplied both as a quality assurance method after installationof low-sloped roofs and as field inspection methods. Theleakage detection can also be extended to terrace slabs and thewhole building envelope.</p><p>To investigate the strength of jointsbetween sheet metaland roofing membranes, several small-scale tests and somelarge-scale tests were performed. The test methods weredeveloped to match the loads that can be expected on this kindof joints.</p><p>A number of water leak-detection methods were evaluatedthrough application on test roofs. Some of the methods todetect leaks on low-sloped roofs can also be used to detect airleakage in other parts of the building envelope. To develop andevaluate air leak-detection procedures, selected methods wereused in two case studies.</p><p>The circumstances regarding welding of the material jointswere found to have great impact on the strength. The roofshould be designed so no long-term strain will appear since acomparatively low stress may damage the joint over time.</p><p>The performance of the leak-detection methods depends on theroofing material. All methods tested were an improvementcompared to visual inspections. Different recommendedapproaches for leakage detection and quality control is given.The case studies show that air leakage detection could beperformed with good accuracy. The potential difference methodcould without doubt be a tool for leakage localisation inwaterproofing layers both on roofs and in terrace slabs.</p><p><b>Keywords:</b>Roofing, roof membrane, durability,waterproofing, leakage, wind-load, non-destructive testing,NDT, BSL4, BSL3, air leakage, building envelope</p>

Increasing surface pressure buildup levels and surface venting flow rates on intermediate wellbore casing strings provided an opportunity to analyze wellbore field data to determine a distribution of leakage path permeability values. The gas leakage source in the leaky wellbore originated at depth, and formation gas/fluid traveled along defects in the cement to accumulate at the surface wellhead. The most likely pathway is the cement interface with casing or formation. Due to uncertainty about the location of the leak, and the different methods that were used for calculating leakage parameter values, a range of leakage path permeability values was produced. Most leakage pathway permeability values were greater than intact cement permeability (few microdarcies). This finding supports the practice of using cement filled annuli to provide a safe protective barrier against leakage and to prevent gas flow to surface. Proper cementing techniques are presented in order to identify possible reasons for cracks to form. It is hypothesized that the higher permeability values are a result of cracks in the cement interface with the casing or formation. These types of defects could also be found in wellbores that are in communication with CO2 sequestration reservoirs. The risk of leakage along such existing wellbores associated with CO2 sequestration projects is quantified by the distribution of leakage path permeability. The gas migration path through existing leaky wellbores is an analog for wellbores that are in contact with migrating CO2 plumes. Cracks in the leaky wellbores provide a highly permeable conduit for CO2 to migrate out of the injection zone to the surface. By quantifying leakage path permeability, proper leakage risk assessment can be further developed. / text

Large-scale geological storage of CO₂ is likely to bring CO₂ plumes into contact with existing wellbores and faults, which can act as pathways for leakage of stored CO₂ Modeling the flux of CO₂ along a leaky pathway requires transport properties along the pathway. We provide an approach based on the analogy between the leakage pathway in wells that exhibit sustained casing pressure (SCP) and the rate-limiting part of the leakage pathway in any wellbore that CO₂ might encounter. By using field observations of SCP to estimate transport properties of a CO₂ leakage pathway, we obtain a range of CO₂ fluxes for the cases of buoyancy-driven (post-injection) and pressure-driven (during injection) leakage. The fluxes in example wells range from background levels to three orders of magnitude higher than flux at the natural CO₂ seep in Crystal Geyser, Utah. We estimate a plausible range of fault properties from field data in the Mahogany Field using a shale gouge ratio correlation. The estimated worst-case CO₂ flux is slightly above background range. The flux along fault could be attenuated to zero by permeable layers that intersect the fault. The attenuation is temporary if layers are sealed at other end. Counterintuitively, greater elevation in pressure at the base of the fault can result in less CO₂ leakage at the top of the fault, because the capillary entry pressure is exceeded for more permeable layers. Since non-negligible leakage rates are possible along wellbores, it is important to be able to diagnose whether leakage is occurring. Concurrent pressure and temperature measurements are especially valuable because they independently constrain the effective permeability of a leakage path along wellbore. We describe a simple set of coupled analytical models that enable diagnosis of above-zone monitoring data. Application to data from a monitoring well during two years of steady CO₂ injection shows that the observed pressure elevation requires a model with an extremely large leakage rate, while the temperature model shows that this rate would be large enough to raise the temperature in the monitoring zone significantly, which is not observed. The observation well is unlikely to be leaking. Extraction of brine from the aquifer offers advantage over standard storage procedure by greatly mitigating pressure elevation during CO₂ injection. A proper management of the injection process helps reduce the risk of leakage associated with wellbores and faults. We provide strategies that optimize the injection of CO₂ which involve extraction of brine in two scenarios, namely injecting dissolved CO₂ and supercritical CO₂. For surface dissolution case we are concerned with bubble point contour, while for supercritical CO₂ injection we are concerned with breakthrough of CO₂ at extractors. In a surface dissolution project, the CO₂ concentration front shape when it reaches the saturation pressure contour defines the maximum areal extent of CO₂-saturated brine and hence the aquifer utilization efficiency. We illustrate the reduction of utilization efficiency due to heterogeneity of the aquifer. We develop an optimal control strategy of the injection/extraction rates to maximize the utilization efficiency. We further propose an optimal well pattern orientation strategy. Results show that the approach nearly compensates the reduction of utilization efficiency due to heterogeneity. In a supercritical CO₂ injection that involves brine extraction, the problem of avoiding breakthrough of CO₂ at extraction wells can be addressed by optimizing flow rates at each extractor and injector to delay breakthrough as long as possible. We use the Capacitance-Resistive Model (CRM) to conduct the optimization. CRM runs rapidly and requires no prior geologic model. Fitting the model to data recorded during early stages of CO₂ injection characterizes the connectivities between injection and brine-extraction wells. The fitted model parameters are used to optimize subsequent CO₂ injection in the formation. Field illustration shows a significant improvement in CO₂ storage efficiency. / text

The Little Grand Wash normal fault near Green River, eastern Utah, hosts a series of naturally occurring CO₂ seeps in the form of active and extinct CO₂-charged springs distributed along the fault zone. I have studied the association of fault structure with CO₂-related alteration as an analogue for the long-term (1,000- to 10,000-year) effects of leakage through faults in CO₂ sequestration reservoirs. Structure and alteration in a portion of the Little Grand Wash fault zone were mapped at a 1:700 scale in order to determine the association of faulting with CO₂-related diagenesis. I combined structural and diagenetic mapping were combined with laboratory analyses of mineralogical, isotopic and textural changes in order to assess controls on the migration of CO₂ traveling up the fault and its effects on the fault itself. The fault zone is 200 m wide at its widest and contains 4-5 major subparallel fault segments that form multiple soft- and hard-linked relay ramps. The area includes a travertine deposit and related sandstone alteration: outcrop-visible coloration, porosity-occluding calcite cement and veins occasionally so abundant that they obliterate the rock fabric. Structural mapping shows that the travertine is located at an intersection of major fault segments constituting the hard link of a 450-meter-long relay ramp. Sandstone alteration is confirmed to be related to the CO₂ seep by mapping its distribution, which shows a decrease in concentration away from the travertine, and by the unique isotopic signature of calcite cement near the travertine. At distances greater than 25 m from the travertine intense alteration disappears, though scattered fault-subparallel veins and patchy, burial-related calcite cement remain. Intense alteration is limited to major fault overlaps and does not permeate the fault zone along its entire length, nor does it extend outside the zone. This indicates that rising CO₂-laden fluids do not flow uniformly through the entire fault zone, but that vertical flow is channeled at fault intersections. In thin section, porosity near the travertine has been extensively or completely occluded by calcite cement. Permeability in some conduit samples is less than 1 mD, three or four orders of magnitude lower than sandstone away from the travertine. In active CO₂ conduits, such reduction in porosity and permeability would occlude the preferred flow conduit and ultimately restrict upward flow of CO₂-charged water. X-ray diffraction detects small amounts of goethite and hematite and a decrease in chlorite-smectite in altered conduit sandstones. Calcite is abundant, but many authigenic minerals predicted by geochemical models of CO₂ influx into sandstone reservoirs are not observed, including kaolinite, aragonite, dolomite, siderite, ankerite or dawsonite. This difference between observed and predicted mineral occurrence likely results from differences in mineral kinetics between natural and laboratory systems. Prediction of leakage risk based on fault geometry improves the ability to assess the suitability of potential carbon sequestration reservoirs, many of which will be faulted. The point seep nature of leakage through a fault zone limits the amount of CO₂ that can escape over time and also enables targeted surface monitoring for CO₂ escape into the atmosphere--both critical for ensuring the effectiveness of injection projects and earning the trust necessary for carbon sequestration to gain public acceptance. The point seep nature of leakage also accelerates the rate at which conduits may seal through mineralization, since precipitation from a large volume of fluid is focused in a narrow conduit. The presence of multiple fossil and active seep locations along the Little Grand Wash fault, active at different times in the geologic past, indicates that cementation may be effective in sealing single conduits but that fault systems with complex geometry such as Little Grand Wash may continue to leak for a long period of time. / text

With the MOSFET scaling practice, the performance of IC devices is improved tremendously as we experienced in the last decades. However, the small semiconductor devices also bring some drawbacks among which the high gate leakage current is becoming increasingly serious. This thesis work is focused on the of gate leakage current reduction in thin oxide semiconductor devices. The method being studied is the Phonon Energy Coupling Enhancement (PECE) effect induced by Rapid Thermal Processing (RTP). The basic MOS capacitors are used to check improvements of leakage current reduction after appropriate RTP process. Through sets of experiments, it is found that after RTP in Helium environment could bring about four orders reduction in gate leakage current of MOS capacitors.