The ability of surface-treated silica nanoparticles to stabilize oil/water emulsions presents us with many interesting avenues of study. The goal of this research is to assess the ability of a dispersion of specially surface-treated nanoparticles to stabilize an oil/water emulsion of prescribed internal structure created by flow within a fracture. We hypothesize that for a set of conditions (nanoparticle concentration, salinity, aqueous to organic phase ratio) a critical shear rate exists. That is, for flow rates that exceed this critical shear rate, an emulsion can be created. Flow experiments were conducted within fractured Boise sandstone and cement cylinders. The Boise sandstone core (D = 1 in and L = 12 in) was cut down its length and propped open to a specific aperture with beads. The fracture was saturated with dodecane then displaced with nanoparticle dispersion, and vice versa while pressure drop across the fracture was recorded. Class H cement cylinders (D = 1 in and L = 3 in) were allowed to set, then failed in compression to create a rough-walled fracture along their length. These fractured cement cylinders were then sealed and encased in epoxy to isolate the fractures. CT scans of the encased fractures were used to determine the aperture width, which is utilized when calculating the shear rate inside of the fracture maintained during an experiment. A dispersion of surface-modified silica nanoparticles and decane were coinjected into both the Boise sandstone and cement fractures and the pressure drop was measured across the fractures at a variety of shear rates. The effluent of each experiment was collected in sample tubes. Observation of the effluent and pressure drop data both support our hypothesis of emulsion generation being possible once a critical shear rate has been reached. Alteration of the injected phase ratio and increased residence time of the two phases inside of a fracture both affect the amount of emulsification occurring within the fractures. Increasing the residence time of both phases within a fracture allows for more opportunities for emulsification to occur, resulting in a greater amount of emulsion to be generated. Injection of high or low volumetric ratios of nanoparticle dispersion to organic phase results in little amounts of emulsion generation; however, between the nanoparticle dispersion to organic phase ratios of 0.25:1 and 2:1 significant amounts of emulsion are generated. / text

published_or_final_version / Civil Engineering / Master / Master of Philosophy

No description available.

There are many variants of leader election algorithm in distributed networks. In this research, an agent based approach to leader election in distributed networks is investigated. Agents have shown to be useful in several ways. In the theoretical perspective, agents sometime help in reducing the message complexity of the system and sometimes help in lowering time complexity. In a more practical sense, agents perform operations independent of the processors, thereby lending a more flexible algorithm supporting different types of networks.

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It is impossible to improve the quality of the machines, to increase their reliability and lifetime if the working conditions and the properties of the material are not analyzed. We must know the type of the material (hardening, softening or cyclically stabile), what is chosen for the constructions in low cycle loading, because strain and stress change during the exploitation and depend on this type. If we know the type of the material, we can determine the possibility of its application in concrete exploitation conditions. Real working conditions of the most constructions are close to loading with limited strain (hard straining), because elastic and plastic deformation is met in the zones of crack and stress concentration, that are surrounded with elastically deformed material. The low cycle loading curves parameters A, and are used for the computation of elastic plastic strain curves. These parameters are obtained from the soft low cycle loading results in many cases. The other possible ways for the determination of parameters A, and are shown in this work. The most investigated materials had the initial instability in the interval . For more objective evaluation of stress strain curves parameters A, and , all values of width of hysteresis loop up to semicycle were rejected as insignificant in comparison with the rest lifetime in cycles range . The parameter for the evaluation of hardening (softening) intensity was determined, when the values of... [to full text]

Solidification/Stabilization (S/S) is a low cost remedial technology that is being used with success to remediate sites that contain higher molecular weight organic compounds, leading to a need to research the interaction of organic contaminants with cement-based S/S materials. The objective of this study was to examine the sorption levels of naphthalene to cement-based S/S materials. Batch testing was performed with S/S materials containing different amounts of organic carbon to investigate the sorption of naphthalene. It was found that sorption values varied, but appear to be dependent on the organic carbon present. Dynamic leach test (ANS16.1 methodology) and SPLP analysis results are presented for intact cement-based S/S materials. Contaminant migration modeling was performed to use the information obtained in the study to compare the sorption capacity of cement-based S/S systems. It was shown that cement-based S/S remediation systems can provide long-term protection against naphthalene contaminant migration.

Filter Cake, which contains leachable nickel and vanadium above the criteria in the Alberta Waste Control Regulation, is produced at an oil sands facility operated by Nexen Inc. and is currently being disposed in a landfill. Bench scale and field tests were performed with stabilization/solidification (S/S) treatment reagents such as Portland cement, fly ash, elemental sulphur, and CETCO Oilfield Service’s proprietary reagents to assess their efficacy at reducing leachable metals in Filter Cake. The CETCO reagents were the most effective treatment for reducing leachable nickel and vanadium in Filter Cake. Treatments with Portland cement were successful in bench scale tests, but inconsistent in field tests. The inconsistent results obtained for Portland cement may have been due to interferences of the cement reactions from factors such as fine particulates. S/S treatments of Filter Cake present a viable waste management option. However, the associated reduced cost and environmental impacts were not substantial.

No description available.

The purposes of this dissertation were to determine: 1) the relationship betweenmuscle thickness change (MTC) as measured by rehabilitative ultrasound imaging(RUSI) and EMG activity in the lumbar multifidus (LM), 2) if motor control changesproduced by experimentally induced pain are measurable with RUSI, 3) if a differenceexists in MTC between subjects with low back pain (LBP) classified in the treatmentbasedclassification system (TBC) system and controls, 4) if MTC improves followingintervention.Current literature suggests sub-groups of patients with LBP exist and responddifferently to treatment, challenging whether the majority of LBP is "nonspecific". TheTBC system categorizes subjects into one of four categories (stabilization, mobilization,direction specific exercise, or traction). Currently, only stabilization subjects receive anintervention emphasizing stability. Because recent research has demonstrated that motorcontrol impairments of lumbar stabilizing muscles are present in most subjects with LBP,it is hypothesized that impairments may be present across the TBC classifications.Study 1: Established the relationship between MTC as measured by RUSI andEMG in the LM. Study 2: Assessed MTC of the LM during control and painfulconditions to determine if induced pain changes in LM and transverse abdominis (TrA)are measurable with RUSI. Study 3: Measured MTC of the LM and TrA in subjects withLBP classified in the TBC system and 20 controls. Subjects completed a stabilizationprogram and were re-tested.The inter-tester reliability of the RUSI measurements was excellent (ICC3,3 =.91,SEM=3.2%). There was a curvilinear relationship (r = .79) between thickness changeand EMG activity. There was a significant difference (p andlt; .01) between control andpainful conditions on 4 of the 5 LM tasks tested and on the TrA task. There was adifference in MTC between subjects and controls on the loaded LM test which varied bylevel and category. All categories were different from control on the TrA. Followingintervention the TrA MTC improved (p andlt; .01). The LM MTC did not (p values from .13-.86).These findings suggest MTC can be clinically measured and that deficits existwithin TBC system. Significant disability and pain reduction were measured.