Explosives place large demands on the lateral load carrying capacity of structures. If these loads are applied on columns, the high pressure transient loads from explosives can result in significant damage to the primary gravity load carrying elements. The loss of these elements, which are responsible from overall strength and stability of the structure, may cause collapse of all or parts of the structure. Therefore, it is important to mitigate the blast loads effects on columns. A comprehensive research study into the design, application, and use of different retrofit systems to mitigate damage to columns under blast loads has been undertaken. This research program, consisting of experimental testing and analytical investigation, sought out retrofits that address the strength of columns as well as those that enhance ductility are explored. Different materials and resistance mechanisms are used to increase column capacity. An experimental testing program was conducted using a shock tube to test the capacity of columns under blast loads. For this program, a total of sixteen reinforced concrete columns were constructed and the data from a further two columns from a previous study was compiled. Of these columns, a total of thirteen were retrofitted to mitigate the effects of blast. Carbon fibre reinforced polymer (CFRP) was applied to eight of the columns in the form of jacketing, longitudinal reinforcement, or the combination of the two. The other retrofits included steel prestressed confinement applied to one column, steel bracing acting as compression members applied to one column, and steel bracing acting as tension members applied to three columns. The columns were tested under incrementally increasing shock tube induced shock wave loading up to failure of the specimen or capacity of the shock tube. The performance of the retrofitted columns was compared with the control columns and against other retrofits. Quantitative comparisons of displacements and strains were made along with qualitative assessments of damage. The results indicated that all the retrofits increased capacity to the column, however, certain retrofits out performed others. The best FRP retrofit technique was found to be the combination of longitudinal and transverse FRP. The prestressed steel jacketing proved to be effective at increasing ductility capacity of the column. The compression brace retrofit was found to be effective in significantly increasing capacity of the column. The tension brace retrofits had the best performance over all the retrofits including the compression brace retrofit. The experimental data was used to validate analysis techniques to model the behaviour of the specimens. This technique reduced the columns to an equivalent single-degree-of-freedom (SDOF) system for dynamic analysis purposes. The reduction to the SDOF system was achieved by computing a resistance to lateral load and lateral displacement relationship. Each retrofit was carefully considered in this analysis including the retrofit’s possible effect on material and sectional properties as well as any force resistance mechanism that the retrofit introduces. The results of the modeling and experimental program were used to develop retrofit design guidelines. These guidelines are presented in detail in this thesis.

The performance of ebullated bed hydroprocessors depends on the fluids distribution system and liquid recycle pan. Given that bubbles do not readily coalesce in the bed, the original bubble size distribution generated at the bubble cap distributor likely impacts buoyancy-based phase separation at the recycle pan. Gas entrained in the liquid recycle increases bed gas holdup at the expense of liquid holdup and product yield. The aim of this work was to investigate the impact of gas-liquid distribution system on resulting bubble properties and dynamics and incorporate a distributor sub-model into an existing fluid dynamics model of the industrial hydroprocessor. The size of initial bubbles formed in the plenum chamber was found to have negligible impact on phase holdups above the distributor. However, resulting bubble properties were found to depend on distributor geometry, distributor power dissipation and gas-liquid velocity ratio. In addition, a new set of scaling laws for gas-liquid distributors, based on dimensional analysis and similitude, was proposed. Geometric scaling was based on matching distributor fractional open area and ratios of critical dimensions. Dynamic similarity was based on matching three dimensionless groups and bubble coalescence behaviour. A bubble size distribution model was then developed. Both pressure and distributor were found to have an impact on individual bubble drag coefficients, as they both altered bubble size distribution. A novel drag model was thus also developed at industrially relevant conditions. Finally, a new gas-liquid distributor sub-model, including bubble size distribution and drag models previously developed, was incorporated into an overall fluid dynamics model of the hydroprocessor. The bubble size distribution model was also coupled with existing gas-liquid separation sub-model to better predict recycled gas and liquid fractions. A sensitivity analysis performed with the overall model revealed distributor configurations with potential of improving the processing capacity of the hydroprocessor.

In vitro and in situ experiments were conducted to evaluate the hypothesis that the nonclassical opioid peptide nociceptin acting on sympathetic preganglionic neurons (SPNs) inhibits spinal sympathetic outflow. First, whole cell patch recordings were made from antidromically identified SPNs from immature (12-16 day old) rat spinal cord slices. Nociceptin (0.1, 0.3, and 1 μM) concentration dependently suppressed the excitatory postsynaptic potentials (EPSPs) evoked by focal stimulation and hyperpolarized a population of SPNs; these effects were naloxone insensitive. L-Glutamate-induced depolarizations were not significantly changed by nociceptin. Results from this series of experiments indicate that nociceptin inhibits the activity of SPNs by either a presynaptic or postsynaptic site of action, whereby the peptide reduces, respectively, the amplitude of EPSPs or the excitability of SPNs. Second, intrathecal injection of nociceptin (3, 10, and 30 nmol) to urethan-anesthetized rats dose dependently reduced the mean arterial pressure and heart rate; these effects were not prevented by prior intravenous administration of naloxone (1 mg/kg). Physiological saline given intrathecally was without appreciable effects. These results, together with earlier observations of the detection of nociceptin-immunoreactive nerve fibers and nociceptin receptor immunoreactivity in the rat intermediolateral cell column, raise the possibility that the opioid peptide, which may be released endogenously, reduces spinal sympathetic outflow by depressing the activity of SPNs.

Cocaine- and amphetamine-regulated transcript (CART) is widely expressed in the rat central nervous system, notably in areas involved in control of autonomic and neuroendocrine functions. The aim of this study was to evaluate the effects of CART peptide fragment 55-102, referred to herein as CARTp, by intrathecal injection on blood pressure (BP) and heart rate (HR) before and after intrathecal glutamate in urethane-anesthetized male Sprague-Dawley rats. CARTp (0.1-10 nmol) administered intrathecally caused no or a small, statistically insignificant increase of blood pressure and heart rate, except at the concentration of 10 nmol, which caused a significant increase of blood pressure and heart rate. Intrathecal glutamate (0.1-10 nmol) produced a dose-dependent increase in arterial pressure and heart rate. Pretreatment with CARTp dose-dependently potentiated the pressor effects of glutamate (1 nmol), which by itself elicited a moderate increase of blood pressure and heart rate. Further, CARTp significantly potentiated the tachycardic effect of glutamate at 1 and 5 nmol, but attenuated the response at 10 nmol. The effect of CARTp was long-lasting, as it enhanced glutamatergic responses up to 90 min after administration. Prior injection of CARTp antiserum (1:500) but not normal rabbit serum nullified the potentiating effect of CARTp on glutamatergic responses. The result suggests that CARTp, whose immunoreactivity is detectable in sympathetic preganglionic neurons as well as in fibers projecting into the intermediolateral cell column, augments spinal sympathetic outflow elicited by glutamate at lower concentrations and may directly excite neurons in the intermediolateral cell column at higher concentrations.

Current procedures for estimating effective length factors for web-tapered members rely heavily on the use of charts and graphs. This makes them difficult to implement using a computer. In addition, they are often based on unrealistic assumptions. In cases where these assumptions are not satisfied, design errors may result. This investigation proposes a modification to an effective length factor expression developed by Lui (1992). This modification allows the expression to be applied to web-tapered members with good accuracy. A derivation of the proposed expression is presented, and the results obtained by applying the expression to a range of frames are compared to the results obtained from second-order finite element analyses. Calculations involved in using the expression are presented. / Master of Science

The gas phase flow patterns in a bubbling column were investigated, using tracer methods to establish the residence time dis­tributive An analogue computer obtained the moments if this distribution directly. The air flow rate and column height were varied. The results showed that as the air flow rate in­creased, although the voidage increased, the mean residence tine decreased. Thus an increasing proportion if the gas phase behaved as a stagnant volume. The results are correlated in terms of a mixed region model. Other work showed that an increase of liquid viscosity, or the inhibition of coalescence, affected only the stagnant volume. The rate of coalescence was investigated and an estimate of its magnitude was obtained. / Thesis / Master of Engineering (ME)

Column flotation cells have become the most popular machine designed for industrial applications that require the separation and concentration of wanted or unwanted minerals from the rest material associated in a pulp. To achieve this process separation an air sparging device, which is required to produce bubbles in the flotation cell is required. In column flotation operations, Sparger sparging devices are employed in column flotation operations to generate small bubbles into the cell with the aim to carry the the desired mineral to the surface for later be recovered and proceeded. However, field studies suggest that air injector sparging systems are not always optimized. Two of the reasonsReasons that contributinge to the lack of optimization areis unfavorable state are: (i) ineffective internal design of the sparging system, and (ii) poor operation techniques employed inby the industrial processing industrial plants. The present project intends to better understand sparging performance into the column cell and how to optimize sparging systems more effectively. To achieve this end, With this in mind, data of for gas-water injection rate, froth addition, and inlet-pressure have been collected and analyzed. The This data not only will facilitate an insight of to better operational practices that plant operators can employ to improve column performance, but it also will make it possible to correct flaws in the design of the sparging systems currently used in column flotation operations. / Master of Science

Column flotation is commonly employed in the processing and recovery of fine mineral particles due to an increase in flotation selectivity unattainable using conventional flotation methods. Such an increase in selectivity is due to the employment of wash water, minimizing hydraulic entrainment of fine gangue particles, and the presence of quiescent operating conditions assisted by the use of various air sparging technologies. High performance air spargers increase the probability of collision and attachment between air bubbles and particles, thereby improving recovery of fine and coarse mineral particles otherwise misplaced to the tailings fraction in conventional flotation cells. Although many high-pressure spargers, including the static mixer and cavitation tube, are currently employed for the aeration of column cells, a low pressure sparger capable of providing equivalent performance while resisting a reduction in aeration efficiency does not exist. In light of escalated energy requirements for operation of air compressors necessary to provide high pressure air to existing external and internal spargers, a low-pressure and porous sparger capable of resisting plugging and scaling was developed. Following the design, construction, and optimization of such a prototype, air holdup and flotation performance testing was completed to verify the viability of the sparger as a replacement to existing aerators. Performance evaluations suggest that the sparger is capable of providing similar functionality to currently employed sparging technologies, but further work is required with regards to manipulation of the porous medium to prevent sparger fouling and sustain high aeration efficiencies. / Master of Science

A tool for analyzing and understanding the behavior of structural systems based on the principle of virtual work was developed by Dr. Finley Charney in the early 1990s. The program was called DISPAR, which stands for DISplacement PARticipation factors, and was written to work in accordance with SAP90 and ETABS. This program became outdated once newer versions of SAP90 and ETABS were released. Starting with version 11 of SAP2000, Computers and Structures released an Open Application Programming Interface (OAPI) which allowed programmers efficient access to the information in SAP2000. With this release came the motivation to update the program DISPAR to work with SAP2000 version 11 and other versions to follow. This thesis provides an overview of how the new version of DISPAR was programmed using VB.Net and OpenGL. This thesis starts off with an in depth discussion and literature review on the development of the principle of virtual work. The literature review covers how virtual work can be used as a tool to understand structural behavior as well as optimize structural performance. The updated version of DISPAR (DISPAR for SAP2000) was then used to analyze the behavior of metal building frames under various loadings. The focus of this study was to determine the effect modeling the column base connection as partially rigid has on wind drift in metal building frames. Before beginning the study, a literature review was conducted on the rotation stiffness provided by typical column base connections. The information obtain in the literature review was then used to create a finite element model of a typical column base connection in a metal building. Once the finite element model was completed, DISPAR for SAP2000 was used to conduct a study on the sensitivity of the rotational stiffness of the column base connection. / Master of Science

The potential for improved selectivity has made column flotation cells a popular choice for upgrading fine coal. Unfortunately, recent production data from full-scale column plants indicate that many industrial installations have failed to meet original expectations in terms of clean coal recovery. Theoretical studies performed using a simple dispersion model showed that this inherent shortcoming could be largely minimized by reconfiguring the columns to operate in series as a cell-to-cell circuit. Follow-up field data showed that this low-cost modification increased flotation recovery as predicted by the dispersion model. This study presents the key findings obtained from the field investigation and provides generic guidelines for designing multi-stage column circuits. / Master of Science