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No description available.

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

The geographic location of Fezile Dabi District Municipality is unique in the sense that it is one of five district municipalities in the Free State Province that borders on five district municipalities and three provincial boundaries. The Vaal River, a valuable domestic, industrial and agricultural water resource for millions of South Africans, forms one of the administrative boundaries of this district municipality and of the Free State Province. However, despite the vital role the Vaal River plays in the Fezile Dabi region, there is poor water management and assessment system in place. There is a lack of intergovernmental and trans boundary efforts to assess water quality by both district municipalities and provinces. The status of the Vaal River as a visible aquatic boundary line provides an excellent opportunity to develop a trans boundary collaborative water quality monitoring strategy between Fezile Dabi District Municipality and its neighbouring district municipalities. The only way to ensure the safety of water and a healthy environment for all is by addressing the challenges of water quality monitoring in a Trans boundary, integrated and multidisciplinary manner. This study provides a strategy for Fezile Dabi District Municipality and its neighbours by proposing an ideal structure to optimise effective water quality monitoring between them. Firstly, it gives an explanation of what is meant by water quality monitoring as a key performance area of municipal health services. Secondly, information is provided and proposals made on how to integrate water quality monitoring across municipal boundaries. Thirdly, the study suggests how trans boundary collaboration can contribute to improving water quality assessment strategies between Fezile Dabi District Municipality and its adjacent district municipalities. Lastly, an exposition of an ideal organisational structure and methods to optimise effective water quality monitoring between Fezile Dabi District and these municipalities is provided. A way forward is proposed in terms of a structure negotiated and developed at an environmental health workshop held on 28–29 March 2012 in Sasolburg. / Thesis (M. Development and Management (Water Studies))--North-West University, Vaal Triangle Campus, 2013

The observed physiological dynamics of an infant receiving intensive care contain a great deal of information about factors which cannot be examined directly, including the state of health of the infant and the operation of the monitoring equipment. This type of data tends to contain both common, recognisable patterns (e.g. as caused by certain clinical operations or artifacts) and some which are rare and harder to interpret. The problem of identifying the presence of these patterns using prior knowledge is clinically significant, and one which is naturally described in terms of statistical machine learning. In this thesis I develop probabilistic dynamical models which are capable of making useful inferences from neonatal intensive care unit monitoring data. The Factorial Switching Kalman Filter (FSKF) in particular is adopted as a suitable framework for monitoring the condition of an infant. The main contributions are as follows: (1) the application of the FSKF for inferring common factors in physiological monitoring data, which includes finding parameterisations of linear dynamical models to represent common physiological and artifactual conditions, and adapting parameter estimation and inference techniques for the purpose; (2) the formulation of a model for novel physiological dynamics, used to infer the times in which something is happening which is not described by any of the known patterns. EM updates are derived for the latter model in order to estimate parameters. Experimental results are given which show the developed methods to be effective on genuine monitoring data.

A study was made of the phosphorus ecology of the Swale - Ouse river in northern England. It ranges from a stream draining a peat moorland to a mature river influenced by urbanisation (estimated population 250 000) and intensive agriculture. The aims were to assess the concentration and variability of aqueous N and P on spatial and temporal scales, and the response of two common mosses, Fontinalis antipyretica and Rhynchostegium riparioides, to those changes. Key aspects included analysis of water chemistry, internal nutrient contents of mosses, and 'surface' phosphatase activity. The rate of activity of m situ plants was measured over an annual period, in conjunction with short-term studies of transplanted populations. Studies of phosphatase activity in the water also were carried out to assess the biological cycling of phosphorus. Aqueous total phosphorus and total dissolved nitrogen concentration increased on passing down the river. In the upper reaches, total phosphorus comprised equal contributions of dissolved organic and inorganic phosphorus, which were almost certainly derived from diffuse sources. Further downstream, total phosphorus was almost entirely comprised of inorganic phosphorus from point source inputs. The nitrogen and phosphorus content of Fontinalis antipyretica and Rhynchostegium riparioides increased on passing downstream, consistent with the water chemistry. The rate of phosphomonoesterase activity of both mosses was high in the upper reaches of the river, and was inversely related to nutrient content. Fontinalis antipyretica sampled from streams draining peat moorland was shown to have a high phosphodiesterase : phosphomonoesterase ratio. A possible explanation for this is that peat is a potentially rich source of phosphodiester substrate, although increased phosphodiesterase activity may be a response to extreme phosphorus limitation. Transplantation of F. antipyretica showed that internal nutrient content and phosphatase activity respond to changes in ambient nutrients. Aqueous phosphomonoesterase activity was studied over a 12-month period. Laboratory and field studies suggest it plays an important role in the. phosphorus dynamics of the Swale - Ouse river system.

The gas turbine engine has a wide range of applications, these include industrial and aerospace applications on locomotive, ferry, compressor and power generation, and the most popular application will be for the air transportation. The application for air transportation including military and commercial aircraft is highly sensitive to safety concerns. The engine health monitoring system plays a major role for addressing this concern, a good engine monitoring system will not only to provide immediate and correct information to the engine user but also provide useful information for managing the maintenance activities. Without a reliable performance diagnosis module involved, there will be not possible to build a good health monitoring system. There are many methodologies had been proposed and studied during past three decades, and yet still struggling to search for some good techniques to handle instrumentation errors. In order to develop a reliable engine performance diagnosis technique, a fully understanding and proper handling of the instrumentation is essential. A engine performance fault pattern matching method has been proposed and developed in this study, two fault libraries contains a complete defined set of 51963 faults was created by using a newly serviced fighter engine component data. This pattern matching system had been verified by different approaches, such as compares with linear and nonlinear diagnosis results and compares with performance sensitivity analysis results by using LTF program engine data. The outcomes from the verications indicate an encouraging result for further exploring this method. In conclusion, this research has not only propose a feasible performance diagnosis techniques, but also developed and verified through different kind of approaches for this techniques. In addition to that, by proper manipulating the created fault library, a possible new tool for analyzing the application of instruments' implementation was discovered. The author believes there will be more to study by using this created fault pattern library. For instance, this fault pattern library can be treated as a very good initial training sets for neural networking to develop a neural diagnosis technique. This study has put a new milestone for further exploring gas turbine diagnosis technique by using fault pattern related methods.

Pedestrian traffic monitoring is in its infancy, and the volatility of pedestrian traffic creates a need for guidance on site selection in traffic monitoring programs. A robust knowledge base surrounding pedestrian traffic patterns and the degree to which a single counting station is representative of a larger area are essential in developing an accurate program for estimating pedestrian traffic volumes. This research analysed long term hourly data from automated pedestrian counting devices on four consecutive blocks along an entertainment area corridor to determine the shifts in temporal pedestrian traffic characteristics and volumes along a corridor. Features of the built environment were identified that can aid in estimating pedestrian traffic patterns along a corridor. Results indicate daily pedestrian traffic volumes can vary significantly between consecutive city blocks, limiting the applicability of a single count location to represent a larger area. Additionally, shifts in temporal traffic patterns occur over short distances. / May 2016

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Previous work in this laboratory revealed that hormone analysis using fecal samples may predict the number of fetuses carried by pregnant ewes at mid- to late gestation. Reliable lambing number prediction is useful to the producer. Using gas chromatography/mass spectrometry the 5��- and 5��-series of pregnanes and selected 4- and 5-pregnenes were monitored in the feces of 36 black and white-face cross ewes during early gestation. Feces were collected at d 5, 19, and 30 post-mating. Endoscopy was used at d 6 to determine the number of corpora lutea, and litter size data were collected at term. The number of copora lutea was not related (P>.05) to hormone concentrations at any of the sampling times (ANOVA-GLM). No differences in hormone levels were detected at d 5 in response to lambing number. At d 19, 5��-pregnane-3,20-dione and 5��-pregnane-3��,20��-diol were higher in ewes carrying triplets than ewes carrying twins (P���.008). At d 30, 3��-hydroxy-5��-pregnan-20-one was higher in ewes carrying triplets than twins (P<.05). Five progestins, including progesterone and 20��-hydroxy-4-pregnen-3- one, were lower at d 5 in ewes that conceived (n=26) than in ewes that did not conceive (n=6) at the first mating (P<.05). Concentrations of ten progestins were different (P<.05) (some higher and some lower) between groups of ewes that conceived at the first mating versus those that conceived at the second mating. In ewes that conceived at the second mating, pregnenolone and 5��-pregnane-3,20- dione were higher (P<.05) at d 5 than at d 5 of their previous non-conceptive cycle. Of the six ewes that were mated a second time, two still did not conceive but had elevated concentrations of three 5��-pregnanes (P<.05). Although there are differences in progestin profiles in ewes carrying different numbers of fetuses, concentrations alone are not adequate predictors of prolificacy at early gestation. It is inconclusive whether detection of pregnancy is possible as early as d 5 of gestation. / Graduation date: 2001