Stainless steel profiled walls have increasingly been used in the process and other industries to protect people and personnel against hydrocarbon or chemical explosions. The existence of various uncertainties, in particular the ones associated with explosion loading and parameters, make the current design and assessment which are based on single degree of freedom (SDOF) and deterministic approach, very complicated and in many cases leading to unreliable design assessment. Therefore, developing an appropriate reliability approach for assessing and designing blast wall structures would greatly assist in improving the safety of personnel and plant facilities. The objective of this research study is to develop a practical framework for performance based design of stainless steel profiled barrier blast walls, with specific focus on reliability assessment by implementing stochastic finite element analysis (SFEA). Initially, the current traditional SDOF method is reviewed to identify the related issues and weaknesses and accordingly an appropriate method for structural assessments of the blast walls is proposed. Furthermore, a comprehensive investigation on various available methods is carried out to identify a suitable probabilistic approach for the reliability assessments. The corresponding reliability of these structures is evaluated with a MCS method, implementing the Latin Hypercube Sampling (LHS) approach. A programming package is developed using Ansys Parametric Design Language (APDL), to generate parametric finite element models and to perform automated reliability assessments. The significant uncertainties are combined with an advanced analysis model to investigate the influence of loading, material and geometric uncertainties on the response of these structures under realistic boundary conditions and connection configuration. Effective implementation of the framework is achieved by the development of a combined programming package to deal with both finite element and reliability analyses. A further development for this research study is associated with the development of performance based design approach, using the results of the probabilistic and finite element assessments. This can be utilised for optimum and appropriate design of the blast wall structures, based on the defined performance levels. Application and practicality of the developed approach and associated programming package is demonstrated through a number of case studies of realistic stainless steel profiled barriers subject to explosion loading. The results of the preliminary probabilistic case studies confirm that the explosion loading is the main influential input parameter and also nonlinearities are more critical than dynamic effects for unstiffened profiled barrier blast walls. An appropriate dynamic load factor (DLF) is proposed for the preliminary stage of the design and assessments. It is observed that using the probabilistic approach can help identify the important variables and parameters to optimize the design of profiled blast walls, and to perform risk assessments for these structures. The study is expanded to develop a performance based design methodology, linking the probabilistic results with various performance levels and associated parameters (e.g., damage levels). The results and discussions of the case studies associated with performance based design assessments confirm the suitability of the proposed framework, and also highlight the complications in defining intermediate levels, without preliminary investigations. This shows that QRA approach and involvement of professionals can play an important role to develop performance levels and the associated objectives. The developed programming package and associated framework are expected to provide valuable guidance to professional design engineers and researchers, by obviating the need for complex computational requirements.

The loss of ice from the Greenland ice sheet is an important contributor to current and future sea level rise occurring due to ongoing changes in the global climate. A significant portion of this ice mass loss comes through the calving of large icebergs at Greenland’s many marine-terminating outlet glaciers. However, the dynamics of calving at these glaciers is currently not well understood, complicating projections of future behaviour of these glaciers and mass loss from the Greenland ice sheet. The use of seismological tools has shown promise as a means of both monitoring and better understanding the dynamics of the calving process at these glaciers. On the global scale, data from the long-standing global seismic network has recorded the occurrence of glacial earthquakes, large long period earthquakes that occur during large calving events at near-grounded outlet glaciers. The occurrence and source parameters of these earthquakes provide insight into the link between glacier calving and climatic and oceanic forcings, as well as information on the large-scale glacier-dynamic conditions under which these major calving events occur. On the more local scale, a deployment of seismometers around an individual glacier has provided insights on the seismic environment of a calving glacier, as well as the more immediate, short-term external drivers of calving events. We consider both local and global seismic data in order to further understanding of the dynamics of the calving process at Greenland outlet glaciers, and find that glacial earthquake production is indicative of a near-grounded terminus at the source glacier. We find that the locations derived from these events are accurate and are sensitive to changes in the calving-front position of the source glacier, and that the active-force azimuths are representative of the orientation of the glacier at the time of calving. We also find that these glaciers are the source of abundant small icequakes, which are strongly tied to the occurrence of major calving events. The small icequakes that occur at Helheim glacier are modulated by semi-diurnal variations in tide height, and potentially control the timing of major calving events by progressively damaging the glacier tongue.

Unexpected melting of Northern Hemisphere ice sheets during periods of regional cooling characterizes the climate of the last glacial period. While the Heinrich Events are the most well-studied example of this phenomenon, Samuel Toucanne and colleagues recently documented evidence of Fennoscandian Ice Sheet melting during Heinrich Stadials, the cold periods during which Heinrich Events occur. In this dissertation, I use the geographic provenance of sediments in the Bay of Biscay, a proxy for Fennoscandian Ice Sheet melting, along with other paleoclimate records to: (1) demonstrate the persistence of abrupt Fennoscandian Ice Sheet melting as a feature of the Pleistocene climate system, (2) develop a self-consistent explanation for the synchronous melting of ice sheets in the North Atlantic region, and (3) elucidate the timing of abrupt climate change in the Northern Hemisphere. I begin by introducing a framework for inferring the subglacial transport distance of fine sediments from coupled provenance and grain size analyses. This chapter untangles the relationships between the source, size, transport history, and geochemical signature of glacigenic sediments in northern Europe, clarifying the geographical significance of sediment provenance in the Bay of Biscay. I then develop a new method for the spectral analysis of unevenly sampled time series. In the following chapter, I apply the new spectral method to time series of Fennoscandian Ice Sheet melting, Laurentide Ice Sheet melting, and solar activity changes during the last glacial period. Doing so reveals a coherence between ice sheet melting and solar activity and helps explain the quasi-periodic melting of ice sheets on millennial timescales. I then extend the neodymium isotope provenance record of Fennoscandian Ice Sheet melting through Marine Isotope Stage 6, demonstrating that enhanced summertime melting of the FIS during Heinrich Stadials is a recurring feature of glacial periods. In the final chapter, I document a relationship between the occurrence of abrupt ice sheet melting in the Northern Hemisphere and the precession of Earth’s spin axis to reveal an astronomical forcing of millennial-scale climate change.

No description available.

No description available.

Novel plastic sheets and foams from vegetable oil-based monomers were produced. These new polyurethanes were synthesized from aromatic polyols, with erucic acid as the starting material. These monomers have the unique feature of containing an aromatic ring which was hypothesized to improve the rigidity of the polyurethane matrices and the overall physical properties of the plastics and foams. The benefits of the aromatic ring were proposed to be enhanced due to three terminal primary hydroxyl groups within the structure of the polyols. Reactions to produce hexasubstituted benzene derivatives containing alcohol groups in positions 1,2,4- and 1,3,5- around the benzene ring were suitably scaled up to provide amounts necessary for polyurethane production and characterization. These isomers (asymmetric and symmetric triols) were separated using chromatography. The pure triols were crosslinked with 4,4-methylenebis(phenyl isocyanate) into polyurethanes sheets (asymmetric and symmetric polyurethane respectively). The physico-chemical properties of these PUs were studied by Fourier transform infrared spectroscopy, x-ray diffraction,, differential scanning calorimetry dynamic mechanical analysis, thermogravimetric analysis coupled with Fourier transform infrared spectroscopy, and tensile analysis. The asymmetric polyurethane sheet and the symmetric polyurethane sheet differed in their glass transition temperatures and crosslinking densities. This variation could be explained by the differences in crosslinking densities, related to the increase in steric hindrance between adjacent hydroxyl groups of the asymmetric triol monomers. It was found that both polyurethanes had similar mechanical and thermal properties. Due to the similar properties of the asymmetric polyurethane and symmetric polyurethane sheets, the monomers were combined together in order to synthesize PU foams. The physical properties of these foams were studied by Fourier transform infrared spectroscopy, differential scanning calorimetry, dynamic mechanical analysis, scanning electron microscopy, thermogravimetric analysis and were analyzed for close cell content and compression strength. The effect of the benzene ring in the monomer structure on the physical properties of these new polyurethane foams was mainly compared with high density canola polyurethane foams previously investigated. It was demonstrated that the physical properties of polyurethane foams made with aromatic monomers are comparable to those made with aliphatic monomers when enhanced with glycerol. / Bioresource and Food Engineering

The miraculous birth of a new life starts by the formation of an embryo. The process by which an embryo is formed, embryogenesis, has been studied and shown to consist of three types of processes: mitosis, cell differentiation and morphogenetic movements. Scientists and medical doctors are still at a loss to explain the fundamental forces driving embryo development and the causes of birth defects remain largely unknown. Recent efforts by the Embryo Biomechanics Lab at the University of Waterloo have shown a relationship between morphogenetic movements that occur during embryo formation and the frequency and orientation of mitosis. To further study this relationship a means of automatically identifying the frequency and orientation of mitosis on time-lapse images of embryo epithelia is needed. Past efforts at identifying mitosis have been limited to the study of cell cultures and stained tissue segments. Two methods for identifying mitosis in contiguous sheets of cells are developed. The first method is based on local motion analysis and the second method is based on intensity analysis. These algorithms were tested on images of early and late stage embryos of the axolotl (Ambystoma mexicanum), a type of amphibian. The performance of the algorithms were measured using the F-Measure. The F-Measure determines the performance of the algorithm as the true mitosis detection rate penalized by the false mitosis detection rate. The motion based algorithm had performance rates of 68.2% on an early stage image set and 66.7% on a late stage image set, whereas the intensity based algorithm had a performance rates of 73.9% on early stage image set and 90.0% on late stage image set. The mitosis orientation errors for the motion based algorithm were 27.3 degrees average error with a standard deviation (std.) of 19.8 degrees for early stage set and 34.8 degrees average error with a std. of 23.5 degrees for the late stage set. For the intensity based algorithm the orientation errors were 39.8 degrees average with std. of 28.9 degrees for the early stage image set and 15.7 degrees average with std. of 18.9 degrees for the late stage image set. The intensity based algorithm had the best performance of the two algorithms presented, and the intensity based algorithm performs best on high-magnification images. Its performance is limited by mitoses in adjacent cells and by the presence of natural cell pigment variations. The algorithms presented here offer a powerful new set of tools for evaluating the role of mitoses in embryo morphogenesis.

This thesis discusses the differences between an automated and design centered layout process. The work has beenconducted at CBG Konsult AB, a service provider of multilingual solutions, translations and localization.The purpose with this work was to investigate some limitations and issues with the layout process involving the languagefamily XSL used for automated layout at CBG Konsult AB.

The miraculous birth of a new life starts by the formation of an embryo. The process by which an embryo is formed, embryogenesis, has been studied and shown to consist of three types of processes: mitosis, cell differentiation and morphogenetic movements. Scientists and medical doctors are still at a loss to explain the fundamental forces driving embryo development and the causes of birth defects remain largely unknown. Recent efforts by the Embryo Biomechanics Lab at the University of Waterloo have shown a relationship between morphogenetic movements that occur during embryo formation and the frequency and orientation of mitosis. To further study this relationship a means of automatically identifying the frequency and orientation of mitosis on time-lapse images of embryo epithelia is needed. Past efforts at identifying mitosis have been limited to the study of cell cultures and stained tissue segments. Two methods for identifying mitosis in contiguous sheets of cells are developed. The first method is based on local motion analysis and the second method is based on intensity analysis. These algorithms were tested on images of early and late stage embryos of the axolotl (Ambystoma mexicanum), a type of amphibian. The performance of the algorithms were measured using the F-Measure. The F-Measure determines the performance of the algorithm as the true mitosis detection rate penalized by the false mitosis detection rate. The motion based algorithm had performance rates of 68.2% on an early stage image set and 66.7% on a late stage image set, whereas the intensity based algorithm had a performance rates of 73.9% on early stage image set and 90.0% on late stage image set. The mitosis orientation errors for the motion based algorithm were 27.3 degrees average error with a standard deviation (std.) of 19.8 degrees for early stage set and 34.8 degrees average error with a std. of 23.5 degrees for the late stage set. For the intensity based algorithm the orientation errors were 39.8 degrees average with std. of 28.9 degrees for the early stage image set and 15.7 degrees average with std. of 18.9 degrees for the late stage image set. The intensity based algorithm had the best performance of the two algorithms presented, and the intensity based algorithm performs best on high-magnification images. Its performance is limited by mitoses in adjacent cells and by the presence of natural cell pigment variations. The algorithms presented here offer a powerful new set of tools for evaluating the role of mitoses in embryo morphogenesis.

Energy use index (EUI) is an important measure of energy use which normalizes energy use by dividing by building area. Energy use indices and associated coefficients of variation are computed for major industry categories for electricity and natural gas use in small and medium-sized plants in the U.S. The data is very scattered with the coefficients of variation (CoV) often exceeding the average EUI for an energy type. The combined CoV from all of the industries considered, which accounts for 8,200 plants from all areas of the continental U.S., is 290%. This paper discusses EUIs and their variations based on electricity and natural gas consumption. Data from milder climates appears more scattered than that from colder climates. For example, the ratio of the average of coefficient of variations for all industry types in warm versus cold regions of the U.S. varies from 1.1 to 1.7 depending on the energy sources considered. The large data scatter indicates that predictions of energy use obtained by multiplying standard EUI data by plant area may be inaccurate and are less accurate in warmer than colder climates (warmer and colder are determined by annual average temperature weather data). Data scatter may have several explanations, including climate, plant area accounting, the influence of low cost energy and low cost buildings used in the south of the U.S. This analysis uses electricity and natural gas energy consumption and area data of manufacturing plants available in the U.S. Department of Energy’s national Industrial Assessment Center (IAC) database. The data there come from Industrial Assessment Centers which employ university engineering students, faculty and staff to perform energy assessments for small to medium-sized manufacturing plants. The nation-wide IAC program is sponsored by the U.S. Department of Energy. A collection of six general energy saving recommendations were also written with Texas manufacturing plants in mind. These are meant to provide an easily accessible starting point for facilities that wish to reduce costs and energy consumption, and are based on common recommendations from the Texas A&M University IAC program.