A PC based waveform acquisition and analysis system has been developed for use in aorta-iliac arterial assessment. A Motorola DSP56001 based system containing dual Analog to Digital converters is used to sample phase quadrature demodulated signals from a commercially available continuous wave Doppler unit. The Power Spectral Density is calculated using an autoregressive model from which the mean velocity waveform is calculated. This waveform is used to calculate the damping factor, vessel compliance and runoff resistance of a simple electrical model of the lower limb arterial circulation using a non-linear regression technique of curve fitting in the time domain. A pilot study using the system shows a significant separation (p < 0.001 Mann Whitney U-test) between the damping factors of a normal control group (quartile range = 0. 15 - 0.25 ; median = 0. 19) and a patient group with angiographically determined aorta-iliac arterial disease (quartile range = 0.45 - 0.89 ; median= 0.49).

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

<p>Advances in mass spectrometry (MS) instrumentation and techniques have provided approaches for complementing current biochemical research. Native mass spectrometry, which aims to analyze intact biomolecules and biomolecular complexes, has become a powerful tool for identifying and measuring different units of complex structures as well as probing interactions among the different units. Ion traps generally are important in native MS workflows because of their ability to accumulate ions and perform multi-stage analyses including fragmentation, photoreactions, and gas-phase reactions with reagent molecules or ions. Native MS, however, has shortcomings primarily due to the preferred ionization technique, electrospray ionization (ESI). ESI tends to distribute signal from a single analyte among a range of charge states. Additionally, the ions generated from droplets tend to carry adducted molecules and ions proportional to the size of the analyte. For analysis of high mass and heterogeneous biomolecular complexes, these shortcomings lead to wide overlapping charge states for different components that might be difficult to interpret correctly. Charge reduction via gas-phase ion/ion reactions facilitates interpretation of native mass spectra by generating product ions that are well separated in <i>m/z</i>. Current sine wave technology limits the upper <i>m/z</i> range of ion traps required for stabilizing and measuring high mass ion/ion reaction products. Digital ion trapping (DIT) technology circumvents the voltage limitations of sine wave technology by varying frequency to achieve high <i>m/z</i>. The combination of ion/ion reactions and DIT operation facilitates further unique probing reactions such as fragmentation reactions of charge reduced biomolecular complexes via neutral collisions and photoreactions. DIT operation also provides a straightforward approach for isolation of high <i>m/z</i> ions using duty cycle modulation to further facilitate analysis of heterogeneous mixtures. This work highlights developments of a home-built 3D ion trap mass spectrometer as a viable native MS platform.</p>

The thermodynamics inside the helium liquefier in the FREIA laboratory still contains many unknowns. The purpose of this project is to develop a theoretical model and implement it in MATLAB, with the help of the CoolProp library. This theoretical model of the FREIA liquefaction cycle aims at finding the unknown parameters not specified in the manual of the manufacturer, starting from the principle of enthalpy conservation. Inspiration was taken from the classical liquefaction cycles of Linde-Hampson, Claude and Collins. We developed a linear mathematical model for cycle components such as turboexpanders and heat exchangers, and a non-linear model for the liquefaction in the phase separator. Liquefaction yields of 10% and 6% were obtained in our model simulations, with and without liquid nitrogen pre-cooling respectively - similar to those in the FREIA liqueuefier within one percentage point. The sensors placed in FREIA showed similar pressure and temperature values, even though not every point could be verified due to the lack of sensors. We observed an increase of more than 50% in yield after adjustments of the heat exchanger design in the model, especially the first one. This constitutes a guideline for possible future improvements of the liquefier. / Termodynamiken bakom heliumförvätskaren i FREIA-laboratoriet innehåller fortfarande många okända aspekter. Detta kandidatarbete syftar till att utveckla en teoretisk modell och implementera den i MATLAB med hjälp av biblioteket CoolProp. Denna modell av FREIA:s förvätskningscykel syftar till att hitta de okända parametrar som inte specificerats av tillverkaren, och baserar sig på principen om entalpins bevarande. Inspiration togs från de klassiska förvätskningscyklerna Linde-Hampson, Claude och Collins. Vi utvecklade en linjär matematisk modell för cykelkomponenter såsom expansionsturbiner och värmeväxlare, och en icke-linjär modell för själva förvätskningen i fasseparatorn. En förvätskningsverkningsgrad på 10% och 6% uppnåddes i våra modellsimuleringar, med respektive utan förkylning med flytande kväve - liknande verkningsgraderna i FREIA- förvätskaren inom en procentenhet. Sensorerna placerade i FREIA visade på liknande tryck och temperaturer, även om bristen på sensorer gjorde att vi inte kunde bekräfta varje punkt. Vi observerade en ökning på mer än 50% i verkningsgrad efter att ha justerat värmeväxlardesignen något, speciellt för den första. Detta kan utgöra riktlinjer för var man framöver kan förbättra den faktiska förvätskaren. / <p>Subject reader/Ämnesgranskare: Roger Ruber</p>

Wireless networks are an iconic technology of today’s modern era, theyare present in our daily activities as can be exemplified by cellular communications,wi-fi, bluetooth, and others. Vector measurements play an importantrole in the design, simulation, and testing of wireless networks and are usedto characterize key devices operating in the radio interface, such as amplifiers,filters, and mixers.Accurate characterization is the key for improving the capacity and efficiencyof wireless networks. As the demand for network capacity continuouslyincreases, the accuracy of vector measurements must also improve. Further,it is anticipated that such trends will continue in the years to come. Consequently,the wireless industry needs to include nonlinear behavior in theircharacterization and analysis, to assess and guaranty the operation of the devices,and to comply to the specifications from governmental regulations. Incontrast to linear behavior, nonlinear behavior presents an additional bandwidthrequirement because the signal bandwidth grows when it passes throughnonlinear devices. In this thesis, vector measurements for devices operatingin wireless networks are studied, emphasizing a synthetic approach for theinstrumentation. This approach enables the use of digital post-processing algorithms,which enhances the measurement accuracy and/or speed and canovercome hardware impairments. This thesis presents the design of a vectorialmeasurement system for wireless devices considering the aforementionedtrends and requirements. It also explores the advantages of the proposedapproach, describes its limitations, and discusses the digital signal processingalgorithms used to reach its final functionality. Finally, measurement resultsof the proposed setup are presented, analyzed and compared to those of modernindustrial instruments. / <p>QC 20130204</p>

Indiana University-Purdue University Indianapolis (IUPUI) / Dynamic Binary Instrumentation (DBI) is one way to monitor a distributed system in real-time without modifying source code. Previous work has shown it is possible to instrument distributed systems using standards-based distributed middleware. Existing work, however, only applies to a single middleware, such as CORBA. This thesis therefore presents a tool named the Standards-based Distributed Middleware Monitor (SDMM), which generalizes two modern standards-based distributed middleware, the Data Distribution Service (DDS) and gRemote Procedure Call (gRPC). SDMM uses DBI to extract values and other data relevant to monitoring a distributed system in real-time. Using dynamic instrumentation allows SDMM to capture information without a priori knowledge of the distributed system under instrumentation. We applied SDMM to systems created with two DDS vendors, RTI Connext DDS and OpenDDS, as well as gRPC which is a complete remote procedure call framework. Our results show that the data collection process contributes to less than 2% of the run-time overhead in all test cases.

Polarization observations of the unique eclipsing binary, Epsilon Aurigae, are being carried out using a new dual beam imaging polarimeter on the 0.36m telescope of the Harry D. Powell Observatory. This bright binary system has a 27.1 year period with an eclipse duration of nearly two years. The primary is known to be a pulsating F0 supergiant with the secondary a large and essentially opaque disk. We report here on the characteristics of the polarimeter and on the status of V-band observations that are being obtained to better understand the system's geometry and the nature of its two components. In particular, the characteristics of the secondary disk remain a puzzle. Results are compared to polarization observations from the 1982-1984 eclipse.

The location of accessory pathways in Wolff-Parkinson-White syndrome patients is performed manually during open heart surgery at Groote Schuur Hospital, using a hand-held roving electrode. This manual procedure is slow and tedious, prolonging the operation and the time for which the patient remains on cardiac bypass. A multichannel electrogram acquisition and display system with a storage facility would significantly reduce the time taken and improve the reliability of locating the accessory pathways. Having considered a number of currently available cardiac mapping systems it was decided that a new system be developed for specific application within Groote Schuur Hospital. The main design goals of this system are to improve accuracy, increase reliability and enhance the speed of the entire mapping procedure with direct benefit to staff and patients. The system is based on an IBM compatible computer and allows for the acquisition of a maximum of thirty-two electrogram inputs. A typical configuration would acquire twenty epicardial, two references (one each from atrium and ventricle), one roving electrode and two surface lead signals. The epicardial signals are obtained from a custom-built electrode belt which is placed around the heart over the atrioventricular groove. The project includes the development of front-end hardware and software for processing, display and storage of electrogram signals. The relative activation times of the signals are displayed under software control in order to facilitate the location of any accessory pathway(s).

Mastitic milk was detected by obtaining conductance measurements using an impedance microbiology Bactometer® 120 SC instruments. Conductance readings taken after 30 min at 25'C separated normal and abnormal milks when readings differed by more than 3% from the variance among instrument module wells. Samples blended from four quarters of a cow indicated milk from one quarter was abnormal if the salt level in the abnormal quarter raised the blend conductivity above that of normal samples and variance among the wells. Either solid or liquid substrates that contained bacterial stimulants could be used to accelerate bacterial acid production or to reduce impedance detection times, each without adversely affecting the ability to detect abnormal milk. However, measurements with liquid substrates varied with the volume of sample in the well. Results suggested that a fixed volume of one ml be used. Such a volume would allow simultaneous detection of abnormal milk and bacterial load on the same sample.

No description available.