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In recent years, there has been considerable interest in developing efficient machine diagnostics and prognostics tools for quantitative estimation of systems condition and remaining useful life. Often, it is beneficial to combine several measures into a single feature for machine condition monitoring purposes. Selection of appropriate features represents a key step to satisfy machine condition monitoring requirements. Gearboxes represent one of those complex systems where classification of fault stages and types (diagnostics) and remaining useful life prediction (prognostics) remain a challenging task. This thesis focuses on certain aspects of engineering tribology related to gearbox components diagnostics and prognostics based on multi-sensor measurements. A dynamic large-scale mechanical system test-bed has been designed, built, and commissioned. This apparatus is based on the accessory gearbox of the GE J85 turbojet engine, which operates in a number of aircrafts, such as the Canadair CT-114 Tutor. The test rig is equipped with a high speed data acquisition system along with a variety of sensing technologies such as vibration, sound, and acoustic emission transducers in addition to thermocouples, power cells and loading mechanisms. Various attributes are compared for detecting faulty gears and a non-parametric statistical method is used as a quantitative measure of transmission quality. The feature importance level is determined by the significant difference level; and the independent coefficient of the candidate feature is used to compare and rank different time and frequency features. An optimal feature set is then evaluated using the support vector machine classification method by considering a monotonically increasing classification rate. In addition, the selected feature subset has the potential to achieve a better recognition rate than those selected by other heuristic methods such as the mutual information method. This thesis also introduces two metrics which identify the appropriate prognostic feature: load stability ratio and degradation value. The two criteria can be used to compare candidate prognostic features to determine which are most useful for prognosis. An optimization-based method is then used to obtain the optimal feature. The optimized feature can be used with a degradation path modeling to estimate RUL (remaining useful life) for the specific gear system. / Thesis (Ph.D, Mechanical and Materials Engineering) -- Queen's University, 2013-04-27 16:51:19.654

Master of Engineering / Turbulent propagating premixed flames are encountered in spark ignition engines, gas turbines, industrial burners, as well as in vented gas explosions. In all these applications, the flame fronts interact with complex solid boundaries which not only distort the flame structure but directly affect the propagation rate in ways that are not yet fully understood. This thesis aims to provide both a quantitative and qualitative understanding of the link between overpressure, flame front wrinkling and turbulence levels generated in the propagating medium. This is an issue of importance for the provision of improved sub-models for the burning rates of premixed flames. An experimental chamber was constructed where controlled premixed flames were ignited from rest to propagate past solid obstacles and/or baffle plates strategically positioned in the chamber. Laser Doppler Anemometry was used to measure the velocity field and turbulence fields while pressure transducers were used to obtain pressure-time traces. In addition to this Laser-Induced Fluorescence of the Hydroxyl radical is was to image the flame front as it consumes the unburnt fuel captured in the re-circulation zone behind the main obstruction. The thesis reports on the effects of various parameters such as the inclusion of grids and obstructions, blockage ratio, and repeated obstacles to explore possible correlations between the pressure and the flow-fields. Pressure, velocity and LIF images were correlated and analysed to prove the significance of grid location and number on overall turbulence intensity. Corresponding flow field parameters such as flame front wrinkling, peak overpressure and RMS all combine to conclusively demonstrate their interaction and influence to turbulence intensity. By progressively positioning more grids further downstream, consequent rises in the flow field parameters and the establishment of positive trends indicates the overall significance of kernel development and flow disturbances in relation to turbulence generation.

Turbulent liquid sheets have been proposed to protect solid structures in fusion power plants by attenuating damaging radiation. For the High-Yield Lithium-Injection Fusion Energy (HYLIFE-II) inertial fusion energy (IFE) power plant concept, arrays of molten-salt sheets form a sacrificial barrier between the fusion event and the chamber first wall while permitting target injection and ignition. Thick liquid protection can help make fusion energy commercially attractive by reducing chamber size and prolonging chamber lifetime. Establishing an experimental design database for this basic building block flow will provide valuable information about various thick liquid protection schemes and allow reactor designers to establish acceptable tolerances between chamber components. Turbulent water sheets issuing downwards into ambient air were studied experimentally at Reynolds numbers of 53,000 ??0,000 and Weber numbers of 2,900 ??,000 based on average velocity and the short dimension of the nozzle exit ( and delta). Initial conditions were quantified by the streamwise (x) and transverse (z) velocity components using laser-Doppler velocimetry just upstream of the nozzle exit. Characterization of the mean free-surface position and free-surface fluctuations, or surface ripple, and estimation of the amount of mass ejected as droplets from the free surface were quantified in the near-field (within 25 and delta of the nozzle exit). Surface ripple and mean sheet geometry were determined directly from planar laser-induced fluorescence visualizations of the free surface. The droplets due to the turbulent breakup of the jet, termed here the hydrodynamic source term, were measured using a simple collection technique to within 1 and delta of the nominal free surface of the jet. The influence of various passive flow control techniques such as removing low-momentum fluid at the free surface (boundary-layer cutting) on sheet geometry, surface ripple, and turbulent breakup were also quantified. The data obtained in this research will allow designers of inertial fusion energy systems to identify the parameter ranges necessary for successful implementation of the thick liquid wall protection system.

In this dissertation, three types of paper-based analytical devices for point-of-care biosensing, a potentiometric method for analyzing percent hemoglobin A1c (%HbA1c) and a PDMS-glass microelectrochemical device for highly reproducible amperometric measurement in microdroplet, are described. The first paper-based sensing device is fabricated using the principles of origami (paper folding). The three-dimensional origami paper analytical device (oPAD) is fabricated on a single sheet of flat paper in a single photolithographic step and assembled by simply folding the paper by hand. Following analysis, the device can be unfolded to reveal each layer for optical and fluorescent read-out. The second type of paper-based device has an integral aluminum/air battery as the power source and reports its output using Prussian blue as an electrochromic indicator. The integrated aluminum/air battery powers both the electrochemical sensor and the electrochromic read-out. The applicability of the device to point-of-care sensing is demonstrated by qualitative detection of glucose and H2O2 in artificial urine. The third type of paper-based device (oPAD 2) uses an aptamer to recognize the analyte, adenosine, a glucose oxidase tag to modify the relative concentrations of an electroactive redox couple, and a digital multimeter to transduce the result of the assay. Adenosine is quantitatively determined using this device with a detection limit of 11.8 uM. The method for measuring HbA1c concentration, hemoglobin concentration, and thus %HbA1c in human blood is based on potentiometry. We use Alizarin red s (ARS) as a redox indicator. The potential shift of ARS owing to diol-boronic acid complexation is used to determine the HbA1c, which is a competitor of ARS for the complexation reaction. The concentration of Hb is determined by reacting it with Fe(CN)₆³⁻ and measuring the potential shift arising from the reduction of Fe(CN)₆³⁻ by Hb. The results obtained for %HBA1c in human blood are in good agreement with those determined using a reference method. The method for highly reproducible chronoamperometric analysis of the contents of microdroplets is developed. Aqueous microdroplets (~ 1 nL) and separated by a fluorocarbon solvent are generated within a microfluidic device using a T-shaped junction. Highly reproducible quasi-steady-state currents (relative standard deviations = ~ 2%) are observed when the microdroplets are stretched by a factor of 10 in a narrowed segment of a microchannel, which leads to desirable intradroplet mass transfer characteristics. Importantly, the design of the microelectrochemical device ensures direct contact between intradroplet redox molecules and the electrode surface to study inner-sphere electrocatalytic processes such as the oxygen reduction reaction. Finite-element simulations are presented that are in accord with the experimental findings. / text

ITC/USA 2014 Conference Proceedings / The Fiftieth Annual International Telemetering Conference and Technical Exhibition / October 20-23, 2014 / Town and Country Resort & Convention Center, San Diego, CA / While great strides have been made in recent years by government agencies in deploying proactive network security tools, the federal government as a whole desires to continue to press the state of the art in protecting its IT infrastructure. To this end, the US Department of Homeland Security (DHS) has created the Continuous Diagnostic and Mitigation (CDM) program [1] (also known as Continuous Monitoring, CM). It strives to establish a technology framework whereby agency federal government IT networks can be continuously monitored for threats and vulnerabilities, providing an analysis and correlation capability that will enable entities to better evaluate risk. It also defines a hierarchical dash-boarding capability that facilitates both aggregation and communication of each agency's network health status into abstracted levels of summary so the federal system as a whole can be better evaluate their IT security posture. Going forward, these technologies will dramatically impact all government agencies, the Department of Defense (DOD), and commercial entities.

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No description available.

The ability to rapidly, sensitively, and accurately detect the presence of a pathogen is a vital capability for first responders in the assessment and treatment of scenarios such as disease outbreak and bioterrorism. Nucleic acid tests such as the polymerase chain reaction (PCR) are supplanting traditional techniques due to the improved speed, specificity, sensitivity, and simplicity. Still, amplification by PCR is often the bottleneck when processing genetic samples. Conventional PCR machines are bulky, slow, and consume large reagent volumes and an affordable, compact, efficient, easy-to-use alternative has yet to emerge. In this work, a microfluidic PCR platform was developed consisting of a low-cost, multi-chamber polymer microchip and a laser-mediated thermocycler capable of independent thermal control of each reaction chamber. Innovations in polymer microchip modeling, fabrication, and characterization yielded a low-cost solution for sample handling. A simple optical system featuring an infrared laser diode and solenoid-driven optical shutter was combined with a microfluidic temperature measurement system utilizing embedded thermocouples to achieve rapid thermocycling capable of multiplexed temperature control. We validated the instrument with sensitive amplifications of multiple viral targets simultaneously. This technology is a breakthrough in practical microfluidic PCR instrumentation, providing the foundation for a paradigm shift in low-cost, high-throughput genetic diagnostics.