Based on a thorough examination of museum and field Climactichnites specimens, two species of this trace, which is restricted to North America, are recognized, each representing a unique behavioral variant. C. wilsoni represents surface-produced trackways, whereas C. youngi is re-erected for subsurface burrows. Burrowing behavior is supported by the presence of C. youngi within beds, the orientation of burrows inclined to bedding, and the presence of distinct burrow fills. Burrows are distinguished from surface traces by characteristics including the absence of lateral ridges and the presence of mm-sized striations superimposed on the trace. Burrowing behavior was previously unknown and represents a new behavior for the animal. A new ichnospecies, Musculopodus sedentarius, is erected for sedentary impressions of the animal. In the future Musculopodus may be expanded to include the resting traces of other soft-bodied animals known from fossils. Analysis of Climactichnites indicates that the trackmaker was elongate, bilaterally symmetric, dorsoventrally flattened, and soft-footed. These characteristics are consistent with the trackmaker being a primitive mollusk or mollusk-like animal. Unlike other Neoproterozoic and Cambrain mollusks, such as Matthevia, Wiwaxia, and Odontogriphus, the Climactichnites trackmaker could reach considerable size. At up to 29 cm wide and possibly 67 cm long, it was one of the largest animals of its time. During locomotion, the animal generated muscular waves along the sole of its foot, which was extended and clamped into the substrate. Contraction of pedal muscles then pulled the body forward. This method of locomotion is similar to that employed by some gastropods, including Bullia and Polinices, which make Climactichnites-like trackways in exposed intertidal settings today. However, these modern trackways are not preserved because they are eroded by wind, waves, tides and subsequent bioturbation, as experiments confirm. Abundant microbial sedimentary structures associated with Cambrian occurrences suggests that microbial binding may have mediated the preservation of Climactichnites. Two lines of evidence suggest that the Climactichnites trackmaker may have been one of the first animals to venture onto land: the co-occurrence of subaerially-produced sedimentary structures, such as adhesion structures and raindrop impressions, and trackways that span shoreline depth gradients and exhibit variable preservation quality along their length.

<p> The time relationship of metabolically important trace metals (Fe, Cu, Zn, Co, Cd, Cr) in Lake Erie plankton were analyzed from samples collected during an algal (Aphanizomenon) bloom. Iron and cobalt showed a rapid increase in concentretion during the initial period of the bloom, followed by a decrease and levelling off to an equilibrium value. Copper and zinc were found to behave similarily undergoing a slight decrease at the beginning and then steadily increasing in concentration with time. Different depths of sampling were correlated to the life-death cycle of the organism and specific metal concentration trends. Algae from the lowest level of sampling (9.7 m; dead organism level) exhibited an increasing nutrient concentration (Fe, Zn, Co, and PO4) with time.</p> <p> Factor analysis suggested a Fe, Co, depth, 1/Biomass relationship; a Cu, Zn relationship; and a PO4, time relationship. The first two were verified from the experimental results; the last was not.</p> / Thesis / Bachelor of Science (BSc)

The use of InGaAsP semiconductor lasers as radiation sources in gas and liquid detection is described in this thesis. Single mode operation and tunability were studied in several schemes including diode lasers with a short external cavity (SXC), diode lasers with multiple short external cavities (MSXC), and a grating external cavity (GEC) diode laser. Comparisons of SXC, MSXC and GEC lasers are given in terms of tunability, side mode suppression ratio (SMSR), stability, and ease of construction and operation. In highly sensitive gas detection, the harmonic content of residual amplitude modulation (RAM) for current modulation of the diode lasers was studied based on the concept that the light intensity rather than the electric field is directly modulated by the injection current. Formulae for RAM and the absorption signals are given for injection current modulation spectroscopy with diode lasers. Water vapour was detected by using InGaAsP SXC and DFB diode lasers, and an electronic subtracter was employed to reduce the detection noise. A sensitivity of ~ 1.6 x IO-6 in units of equivalent absorbance in an equivalent noise bandwidth of 1.25Hz was obtained. In liquid detection, InGaAsP laser diodes with multiple short external cavities (MSCX’s) were developed to provide a wide spectral coverage, up to 72nm spectral coverage was achieved. Liquid detection by MSXC diode lasers was studied in conjunction with multivariate calibration methods, i.e., principal component regression (PCR) and partial least squares (PLS). A sensitivity of 0.1% H2O in D2O was achieved and the limiting noise source was assessed. Three component mixtures of H2O, acetone and methanol were studied in terms of regression factors and outlier detection in the PCR and the PLS algorithms. To achieve even broader tunability by means of external cavity, work on making broad gain peak InGaAsP/InP lasers was initiated. / Thesis / Doctor of Philosophy (PhD)

The Neoarchean greenstone belts of the Canadian Superior Province host world-class Au and base metal (Cu-Zn-Pb) massive sulfide deposits with distinct geological features, including a wide range of different host rocks and crustal settings. The range of settings is reflected in the trace metal signatures of their ores. This study examines the trace element geochemistry of pyrite from 55 different Archean volcanogenic massive sulfide (VMS) deposits in Canada to test the relationship to their host rocks, the deposit sizes and their grades. The database includes 258 samples of pyrite from 47 deposits in the Abitibi Greenstone Belt (AGB), together with 30 samples from 8 deposits in the Western Superior (Sturgeon Lake, Uchi, Benny, and Manitouwadge belts) and 45 samples from 6 deposits in the Slave Province (Hackett River, Amooga Booga, and High Lake belts). We used statistical methods to characterize the trace element geochemistry of pyrite in grab samples from the deposits, as well as larger samples representing many thousand of tonnes of ore from monthly concentrates. The study focused on pyrite mineral separates comparing samples from different deposits and different ore types within individual deposits. The analysis shows the trace element geochemistry of pyrite is a useful fingerprint of the different mineralizing systems, with trace element enrichments and depletions reflecting different source rocks, inferred temperatures of ore formation, and the scales of the hydrothermal systems. A comparison of the Abitibi samples to other deposits in the Superior Province shows distinct trace element signatures between primitive and more evolved crustal settings of different age. Similar results are found among 102 samples of pyrite from 30 deposits in Proterozoic and Phanerozoic belts across Canada. District-scale variations in pyrite chemistry mainly reflect host rock and correlate different bulk Cu/(Cu+Zn) grade ratios of the deposits. Pyrite samples from Cu-rich deposits are enriched in Cu, Bi, Co, Ni, Se, Te and Mo; whereas pyrite samples from Zn-rich deposits are enriched in Pb, Ag, Cd, In, Ga, Sn, As, Sb, Hg and Tl. The same patterns are observed in Cu-rich versus Zn-rich zones of individual deposits. Statistical analyses reveal pyrite samples from VMS deposits in the AGB that are associated with primitive mafic-ultramafic tholeiitic rocks (e.g., Potter-Doal and Genex from Timmins, and East Sullivan and Dunraine from Val d'Or camps) are enriched in Cu (>5000 ppm), Co (>1500 ppm), Se (>4000 ppm), and Ni (>250 ppm), whereas pyrite from deposits associated with tholeiitic to calc-alkaline felsic rocks (e.g., Abcourt-Barvue from the Amos-Barraute camp) are commonly enriched in Pb, Ag, Au, Cd, In, Sn, As, Sb, Hg, Tl (10s to 100s of ppm). These variations closely match primary trace element abundances in unaltered volcanic rocks compiled from over 4000 high-quality analyses of samples from the Superior Province. Whole-rock data for rhyolite confirm high concentrations of Pb, Ag, Bi, Te, Cd, In, Ga, Sn, Hg, and Tl compared to basalt and komatiite, which have higher Cu, Co, Ni, and Se. The variation in trace element concentrations in pyrite is remarkably consistent for different deposits. We note that randomly sampled pyrite from almost any part of a deposit with a bulk enrichment in a particular element shows notable enrichment in that element compared to pyrite from other deposits. Pyrite from a deposit with a bulk enrichment in Te, for example (Quemont in the Noranda camp), will almost certainly contain more Te than pyrite from other Te-poor deposits. We test this observation among 47 deposits for 15 different elements. Pyrite samples from Au-rich VMS deposits (e.g., Horne, Quemont, Bousquet #2, and Dumagami) have anomalous Au (>6 ppm) and Te (>70 ppm). Co-enrichment in other elements such as Bi, Se, In and Sn may reflect a common felsic magmatic source. Other trace element enrichments appear to reflect the scale of the hydrothermal system (e.g., depth and extent of leaching). For example, pyrite samples from several large-tonnage deposits (Kidd Creek, Horne #5 Zone, and Geco) have high Sn concentrations (from 450 to 15000 ppm) possibly reflecting the large volumes of felsic rock from which the Sn was extracted. In other deposits, co-enrichment of Sn with Bi (>100 ppm) and In (>10 ppm) suggest a magmatic contribution to the ore fluids Principal Components Analysis (PCA) combined with hierarchal clustering confirms systematic trace element variability in pyrite from deposits with different host rocks and bulk Cu/(Cu+Zn) ratios. However, pyrite from deposits in different terranes seems to record major differences in the crustal compositions of those terranes. For example, pyrite samples from bimodal-felsic deposits show the same trace element signatures (i.e., enrichments in Ag, As, Sb, and Hg) in the AGB and in the Western Superior. In contrast, pyrite samples from deposits in the Slave craton tend to show a distinct enrichment in Pb, U and Th that may be related to the more mature and thicker crust in the Slave compared to the AGB. Other deposit types (magmatic Cu vein deposits, orogenic Au deposits) also show dramatically different pyrite compositions. Pyrite concentrates from magmatic Cu vein deposits in Chibougamau are enriched in Cu, Co, Ni, Te, As, Sb compared to VMS in the AGB, and samples from orogenic Au deposits in Timmins and Val d'Or are enriched in Au and Mo and depleted in Pb, Bi, As, and Sb compared to VMS. These differences highlight the potential application of the trace element signatures of pyrite during exploration for different deposit types in the same region. Trace element signatures of pyrite in grab samples compared favourably to much larger bulk samples from the same deposits (e.g., monthly concentrates and mine tailings) giving some confidence that the much smaller samples can provide a reliable first-order fingerprint of the deposits as a whole. LA-ICP-MS analyses of individual pyrite grains also agreed well with bulk analyses of pyrite over a wide range of trace element concentrations (10s to 100s of ppm).

Java Pathfinder (JPF) is a tool to debug Java-based software running multiple threads or processes, with a textual output that be may hard to understand. Recent development introduced the possibility to generate a trace from JPF and visualize it in Trace Compass (TC), a general-purpose trace viewing application. Due to difficulties in maintaining and developing new features for TC, Theia Trace Viewer (TTV) has emerged as the replacement for TC. TTV is a browser-based trace viewer and makes it possible to visualize traces without any download or installation by the user. In this work, we migrate the existing functionality of JPF Trace from TC to TTV and conduct a user study on how TTV supports users analyzing JPF traces. Our results show that TTV is a good start and has great potential, but requires further development before replacing JPF results in textual format. / Java Pathfinder (JPF) är ett verktyg för att hitta fel i Javabaserad mjukvara som exekverar med flera trådar eller processer, där resultat skickas ut som text och kan vara svårt att förstå. Nyligen utvecklades möjligheten att generera ett spår och visualisera i Trace Compass (TC), ett program som kan visualisera olika typer av spårformat. På grund av svårigheter med att underhålla och utveckla nya funktioner för TC, så har Theia Trace Viewer (TTV) vuxit fram som ersättaren för TC. TTV är en webbläsare-baserad traceviewer, där det är möjligt att visualisera spår utan att användaren behöver ladda ner eller installera något. I detta arbete, migrerar vi den befintliga funktionaliteten för JPF Trace i TC till TTV och genomför en användarstudie för att ta reda på hur TTV hjälper användare analysera JPF spår. Vårat resultat visar att TTV är en bra början med god potential, men behöver utvecklas vidare innan det går att ersätta JPF resultat i textformat.

Various lines of evidence indicate that levels of anthropogenic pollutants, such as lead, mercury and cadmium, have increased in terrestrial and atmospheric environments since the early 19th century and the advent of industrialization. While the exposure to these three trace elements is a global concern, this study focused primarily on marine environments located throughout the Caribbean. Using ICP-MS, this study aimed to detect and quantify anthropogenic pollutants, specifically lead (Pb), mercury (Hg) and cadmium (Cd), using skeletonized remains of sea turtles as biological proxies for environmental quality. Archaeologically derived (n=5) and mid-late 20th century (n=6) Hawksbill and Green turtles were used to create a chronology of pollution exposure in Caribbean marine environments and establish a pre-industrial baseline for pollution exposure, useful for precisely gauging how human activities in the Caribbean, namely industrialization and tourism, have changed the concentration of these elements over time. Results from this study revealed that the industrial, modern sea turtle sample and the archaeological sample exhibit similar distributions of lead and cadmium ppm levels. Whereas, the mercury datasets revealed that the two samples share differing distributions of ppm levels, but that the archaeological sample yielded the higher mercury concentrations. Based on these results, this study was unable to verify whether skeletal sea turtle remains, specifically humeri, can be used as a biological proxy to reconstruct anthropogenic pollution in marine environments. Furthermore, it failed to quantify pre-industrial to mid-late 20th century anthropogenic lead, mercury, and cadmium pollution in Caribbean Marine Environments.

This thesis explores the Natchez Trace Parkway using the method of repeat photography to determine whether or not the design intent of the Trace has changed since its beginning. Based upon fifteen matched pairs of photographs, which are evaluated based on a content analysis matrix, the original design intent, recent design guidelines, and planned land use maps, the degree of change that has occurred along the Trace is measured. Time has wrought inevitable change along the Trace. The changes that have occurred indicate a further effort to preserve the original design intent of the Trace rather than a shifting of the design intent. No change in design intent is evident in the matched pairs of photographs.

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The IAEA ICSP on Numerical Benchmarks for Multiphysics Simulation of Pressurized Heavy Water Reactor Transients was initiated in 2016 to facilitate the development of a set of open access, standardized, numerical test problems for postulated accident scenarios in a CANDU styled Reactor. The test problems include a loss of coolant accident resulting from an inlet header break, a loss of flow accident caused by a single pump trip, and a loss of regulation accident due to inadvertently withdrawn adjusters. The Benchmark was split into phases, which included stand-alone physics and thermal-hydraulics transients, coupled steady state simulations, and coupled transients. This thesis documents the results that were generated through an original TRACE/PARCS coupling methodology that was developed specifically for this work. There is a strong emphasis on development methods and step by step verification throughout the thesis, to provide a framework for future research in this area. In addition to the Benchmark results, additional studies on propagation of fundamental nuclear data uncertainty, and sensitivity analysis of coupled transients are reported in this thesis. Two Phenomena and Key Parameter Identification and Ranking Tables were generated for the loss of coolant accident scenario, to provide feedback to the Benchmark Team, and to add to the body of work on uncertainty/sensitivity analysis of CANDU style reactors. Some important results from the uncertainty analysis work relate to changes in the uncertainty of figures of merit such as integrated core power, and peak core power magnitude and time, between small and large break loss of coolant accidents. The analysis shows that the mean and standard deviation of the integrated core power and maximum integrated channel power, are very close between a 30% header break and a 60% header break, despite the peak core power being much larger in the 60% break case. Furthermore, it shows that there is a trade off between the uncertainty in the time of the peak core power, and the magnitude of the peak core power, with smaller breaks showing a smaller standard deviation in the magnitude of the peak core power, but a larger standard deviation in when this power is reached during the transient, and vice versa for larger breaks. From the results of the sensitivity analysis study, this thesis concludes that parameters related to coolant void reactivity and shutoff rod timing and effectiveness have the largest impact on loss of coolant accident progressions, while parameters that can have a large impact in other transients or reactor designs, such as fuel temperature reactivity feedback and control device incremental cross sections, are less important. / Thesis / Master of Science (MSc) / This thesis documents McMaster’s contribution to an International Atomic Energy Agency Benchmark on Pressurized Heavy Water Reactors that closely resemble the CANDU design. The Benchmark focus is on coupling of thermal-hydraulics and neutron physics codes, and simulation of postulated accident scenarios. This thesis contains some select results from the Benchmark, comparing the results generated by McMaster to other participants. This thesis also documents additional work that was performed to propagate fundamental nuclear data uncertainty through the coupled transient calculations and obtain an estimate of the uncertainty in key figures of merit. This work was beyond the scope of the Benchmark and is a unique contribution to the open literature. Finally, sensitivity studies were performed on one of the accident scenarios defined in the Benchmark, the loss of coolant accident, to determine which input parameters have the largest contribution to the variability of key figures of merit.