HARVEST
University of Saskatchewan's Repository for Research, Scholarship, and Artistic Work
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THE EVOLUTIONARY HISTORY OF Larix, Picea, and Pseudolarix (PINACEAE) BASED ON FOSSILS FROM THE BUCHANAN LAKE FORMATION, AXEL HEIBERG ISLAND, N.W.T., ARCTIC CANADA
(1993) LePage, Ben A.; Basinger, J.F.
Exquisitely preserved fertile and vegetative remains of Larix, Picea, and Pseudolarix have been recovered from middle Eocene sediments of the Buchanan Lake Formation on eastern Axel Heiberg Island, Canadian Arctic Archipelago. These remains, as well as a review of the fossil record of Larix, Picea, and Pseudolarix, provide a basis for examination and interpretation of the evolutionary and biogeographic history of these representatives of the Pinaceae. The quality and large number of specimens available for study have provided the opportunity to study, in detail, the morphological features of the seed cones. The results indicate that the bracts, together with other features of the cones, are species specific and useful for the identification and separation of fossil, as well as living representatives of these genera. On the basis of seed-cone morphology, one species of Larix, three species of Picea, and two species of Pseudolarix are recognized from the Axel Heiberg Island deposits. The spatial and temporal distribution patterns of Larix, Picea, and Pseudolarix fossils indicate that displacement of taxa between North America and Eurasia likely occurred through Beringia, and that the establishment of these genera in Europe appears not to have occurred until Miocene or Pliocene time, once the climate had sufficiently cooled.
An ecological quantification of the relationships between water, sanitation and infant, child, and maternal mortality
(Environmental Health, 2012) Cheng, June J.; Schuster Wallace, Corinne; Watt, Susan; Newbold, Bruce; Mente, Andrew
Background: Water and sanitation access are known to be related to newborn, child, and maternal health. Our study attempts to quantify these relationships globally using country-level data: How much does improving access to water and sanitation influence infant, child, and maternal mortality?
Methods: Data for 193 countries were abstracted from global databases (World Bank, WHO, and UNICEF). Linear regression was used for the outcomes of under-five mortality rate and infant mortality rate (IMR). These results are presented as events per 1000 live births. Ordinal logistic regression was used to compute odds ratios for the outcome of maternal mortality ratio (MMR).
Results: Under-five mortality rate decreased by 1.17 (95%CI 1.08-1.26) deaths per 1000,p< 0.001, for every quartile increase in population water access after adjustments for confounders. There was a similar relationship between quartile increase of sanitation access and under-five mortality rate, with a decrease of 1.66 (95%CI 1.11-1.32) deaths per 1000,p<0.001. Improved water access was also related to IMR, with the IMR decreasing by 1.14 (95%CI 1.05-1.23) deaths per 1000,p< 0.001, with increasing quartile of access to improved water source. The significance of this relationship was retained with quartile improvement in sanitation access, where the decrease in IMR was 1.66 (95%CI 1.11-1.32) deaths per 1000,p< 0.001. The estimated odds ratio that increased quartile of water access was significantly associated with increased quartile of MMR was 0.58 (95%CI 0.39-0.86),p= 0.008. The corresponding odds ratio for sanitation was 0.52 (95%CI 0.32-0.85),p= 0.009, both suggesting that better water and sanitation were associated with decreased MMR.
Conclusions: Our analyses suggest that access to water and sanitation independently contribute to child and maternal mortality outcomes. If the world is to seriously address the Millennium Development Goals of reducing child and maternal mortality, then improved water and sanitation accesses are key strategies.
The Impacts of Climate Change on Water-, Food-, Vector- and Rodent-Borne Diseases
(Health Canada, 2008) Charron, Dominique; Fleury, Manon; Lindsay, Robbin; Ogden, Nicholas; Schuster Wallace, Corinne
THEORETICAL AND EXPERIMENTAL INVESTIGATIONS ON RESONANT FREQUENCIES AND NATURAL RESPONSE OF STATORS OF ELECTRICAL MACHINES
(1978-02) Girgis, Ramsis Sedhom; Verma, S. P.
Accurate assessment of values of resonant frequencies and natural response of stators is essential for the purpose of acquiring a quiet operation of electrical machines. In this thesis, an analysis of a general nature is developed for the determination of values of resonant frequencies and natural response of stators of encased construction. The derived frequency equation is applicable to all modes of vibration and can deliver information about all possible resonant frequencies of a stator. The analysis is based on the three-dimensional theory of elasticity; and it is capable of delivering information about not only the radial vibrations of stators but also about the torsional and axial vibrations.
Simplified frequency equations are also derived from the general frequency equation for the special cases of uniform vibrations along the stator circumference and along the stator length.
In order to examine the validity of the analysis, extensive experimental investigations were carried out on nine different models which represent stators of small, medium, and large electrical machines. The comparisons made between the experimental and the analytical results prove the general validity of the analysis. The experimental results also confirm the actual existence of several important phenomena predicted by the analysis. These are the phenomenon of dual resonance, the phenomenon of coupling between components of displacement, and the phenomenon of multiple resonances.
The thesis also presents a fundamental experimental study of the manner in which values of resonant frequencies, amplitudes of vibration and frequency response of stators at resonance are affected by the dynamics of teeth, windings, frame, and laminations. The findings of this study would be helpful for proper incorporation of the effects of teeth, windings, frame, and laminations in the process of accurate determination of resonant frequencies and natural response of stators. The physical interpretations of the results given in the thesis would also help in acquiring a better understanding of the vibration behavior of stators in relation to the problem of electromagnetic acoustic noise in electrical machines.
A LEAST ERROR SQUARES TECHNIQUE FOR ESTIMATING THE MAGNITUDE AND FREQUENCY OF A VOLTAGE SIGNAL
(1986-10) Giray, Mahmut Mustafa; Sachdev, M. S.
The use of digital processors in implementing protective relaying functions has attracted considerable attention in the past several years. A major part of a digital processor based relay is the algorithm which estimates the system parameters such as voltage, current and frequency, using the- digitized samples obtained from the system. Developments of suitable algorithms to detect these parameters have been a major challenge to many researchers.
This project is concerned with the development of an algorithm for estimating the magnitude and frequency of a voltage signal using the least error squares curve fitting technique. One of the main considerations is the validity of the algorithm when the magnitude and/or the frequency of the voltage substantially deviate from their nominal values. The effective use of the algorithm under such conditions has been accomplished. The use of the proposed algorithm for implementing a software based volts-per-hertz relay is also demonstrated in this project.
A DIGITAL FREQUENCY-CUM-RATE OF CHANGE OF FREQUENCY RELAY
(1978-11) Giray, Mahmut Mustafa; Sachdev, M. S.
Under-frequency relays are often used to detect deficiency of generation in a power system and to shed load to restore generation-load balance. These relays operate somewhat after the frequency falls to a prespecified level. The difference between the set frequency and the frequency at which load shedding is initiated depends on the rate at which the frequency continues to change. To eliminate this delay frequency-cum-rate of change of frequency relays have been proposed, developed and used. These relays are designed using analog electronic circuits.
The availability of digital processing devices has considerably increased during the last few years while the cost of these devices has been rapidly decreasing. The use of digital processors in system control and protection is at the verge of becoming economically competitive.
This thesis examines the presently used methods of measuring frequency and rate of change of frequency at a power system bus. A few new and novel approaches are then proposed. Also examined are the relative advantages and suitability of these approaches for use in relays based on digital processors. A relay design using the selected techniques of measuring frequency and rate of change of frequency is then outlined. Implementation of this design and relay tests performed in the laboratory are also described.
DESIGN AND IMPLEMENTATION OF A DIGITAL CONTROLLER DEVELOPMENT SYSTEM
(1977-11) Gilchrist, Rodney Dale; Bollinger, K. E.
This thesis describes the design and implementation of a minicomputer based system to develop and evaluate general purpose digital feedback controllers that will operate in the frequency range below ten hertz. An immediate area of application is in the control of turbo generators where additional signals, beyond the standard terminal voltage feedback, are used to provide damping. The feedback of such signals as the machine output electrical power has recently proved advantageous. The controller development system will be a powerful tool in further research in this area. It will allow the development of digital control techniques that could not previously be conveniently tested.
Field test results are described where, as a convenient test case, the digital system satisfactorily emulated an existing power system stabilizer on Calgary Power's Sundance unit 3. Stripchart traces are included that, illustrate the performance of the digital controller relative to the existing installed analog controller. These tests were performed with the generator operating on-line near rated load conditions. The tests point out some of the attributes and shortcomings of the prototype digital controller.
DESIGN AND IMPLEMENTATION OF A VLSI SYSTOLIC ARRAY FOR THE TRANSPORTATION SIMPLEX ALGORITHM
(1989-07) Ghatraju, Lakshmikanth; Bolton, R. J.; Abd-Al-Barr, M. H.
The increasing demand for high speed and improved performance in modem signal and image processing applications, and the availability of low-cost, high-density, high-speed VLSI devices have facilitated the design and implementation of massively parallel processors. The decreasing hardware cost and the emerging computer-aided design facilities have inspired many innovative designs in array processor architecture. One of the important advances in array processor architecture is the "systolic architecture".
In this thesis, a design of a systolic array for the transportation simplex algorithm is proposed. The transportation problem is one of the most important linear programming problems. It is a general problem of allocating limited resources among competing activities in an optimal way. A basic systolic cell design for the transportation matrix array of size n x m is presented.
A simulator for the transportation simplex algorithm was written to verify the proposed design and architecture. The initial basic feasible solution was obtained using Russell's approximation method. Another algorithm to obtain the initial basic feasible solution to the transportation problem based on the "greedy" approach is proposed. The hardware implementation of the basic cell was carried out using the QUISC silicon compiler and the associated standard cell library. The fabricated chips were found to be operational as expected at a maximum operational speed of 10 MHz.
OPTIMIZATION OF A SYSTEM USING STATISTICAL CONTROL THEORY
(1970-01) Ganesan, Krishnamurthy; Fleming, R. J.
The earlier methods for finding the optimum settings of the variable control parameters of a speed governor of a hydro-electric turbine employed arbitrary performance indices and assumed deterministic system disturbances. In this thesis, the Generalized Mean Square Error, the GMSE, is used as a performance index. The GMSE is a function of the correlation functions of input and output and is ideally suited for situations where the disturbance is non-deterministic. A method is developed to describe the random input disturbance statistically and hence to evaluate the input autocorrelation. The other correlation functions required for the evaluation of the GMSE are then derived using the input autocorrelation function and the frequency response function of the system under study. The model used in this study is a particular example of a non-minimum phase, time invariant feedback control system with a transport delay subject to a random disturbance. It is an electric turbo-generator supplying an isolated load. The turbine is provided with the conventional mechanical type governor. The trends in the variations of the GMSE resulting from changes in the statistics of the input disturbance and in the control parameters are shown.
UTILIZATION OF MONTE CARLO SIMULATION IN GENERATING CAPACITY PLANNING
(1986-09) Ghajar, Raymond; Billington, Roy
This thesis presents a formalized and practical approach using Monte Carlo simulation to assess the adequacy of generating systems. A Monte Carlo simulation method is developed to model base load generating units and utilized to calculate the state probabilities in both Markovian and non-Markovian systems. The results obtained from the simulation method are compared with those calculated by analytical methods to determine the effectiveness of simulation. A range of studies for selected unit models is conducted to examine the effect of various distributions on the system state probabilities. The basic simulation model is extended to include the duty cycle of peaking units and to examine the effect of distributional assumptions on the conditional probabilities of failure. The generating capacity models which were developed are then combined with the load model to produce generating capacity adequacy indices. These models provide a method of analysis which relaxes many of the traditional assumptions incorporated in the analytical methods used to calculate reliability indices. The models which were developed are applied to the IEEE Reliability Test System (RTS) and a test system (RBS) developed at the University of Saskatchewan. The potential application of Monte Carlo simulation to calculate an estimate of reliability worth from the individual load loss event data is also illustrated in this thesis.
The models developed in this thesis are capable of explicitly recognizing many unit and system operating considerations which influence system reliability. These models can be utilized to study a wide range of alternatives which differ in terms of unit function and system operation.