Railway track ballast fouling is an ongoing issue without a clear understanding regarding either the cause for generation or the source of the fouling materials. This study was conducted to determine what physical processes are likely causing ballast fouling, where in the track sub-structure fouling material is concentrating, and what factors affect the severity of ballast fouling. A field investigation on a CN railway track was conducted in Joliette, QC during undercutting maintenance operations. Data for in-situ ballast, sub-ballast, and subgrade samples were gathered from a series of trenches excavated through the track embankment. The geotechnical and mineralogical characteristics of a selected set of ballast samples were gathered through a regime of laboratory testing. Grain size distribution data for the select samples was collected from sieve and hydrometer testing. Three sets of LA abrasion tests were conducted on both in-situ and freshly quarried ballast rock to determine the degradation characteristics of the various ballast types. The petrographic analysis of the sample types was conducted using bulk hand sample characterization, thin-section analysis, and X-Ray Diffraction Analysis. The petrographic, grain size, and LA abrasion combined analysis indicated that ballast fouling was primarily caused through degradation of the ballast. The fouling material within the ballast pores was sourced to the abraded pieces of ballast that had degraded over time through XRD and grain size distribution analysis. It was found with statistical confidence that ballast layers with harder, structureless rock types have less fouling material form within the ballast void spaces compared to ballast rock types that are soft on the Mohs hardness scale or have planes of weakness due to structural factors. Analysis of the grain size data also showed that ballast fouling was generally concentrated within the section of the ballast layer directly underlying the steel rail, within the topmost parts of the ballast layers. Overall it was recommended that the effects of chemical degradation on ballast rock types and the historical operational duration of ballast be incorporated into future ballast fouling studies. / Thesis (Master, Geological Sciences & Geological Engineering) -- Queen's University, 2011-09-27 10:01:46.141

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The Mars Science Laboratory Curiosity rover performed coordinated measurements to examine the textures and compositions of aeolian sands in the active Bagnold dune field. The Bagnold sands are rounded to subrounded, very fine to medium sized (similar to 45-500m) with 6 distinct grain colors. In contrast to sands examined by Curiosity in a dust-covered, inactive bedform called Rocknest and soils at other landing sites, Bagnold sands are darker, less red, better sorted, have fewer silt-sized or smaller grains, and show no evidence for cohesion. Nevertheless, Bagnold mineralogy and Rocknest mineralogy are similar with plagioclase, olivine, and pyroxenes in similar proportions comprising >90% of crystalline phases, along with a substantial amorphous component (35%15%). Yet Bagnold and Rocknest bulk chemistry differ. Bagnold sands are Si enriched relative to other soils at Gale crater, and H2O, S, and Cl are lower relative to all previously measured Martian soils and most Gale crater rocks. Mg, Ni, Fe, and Mn are enriched in the coarse-sieved fraction of Bagnold sands, corroborated by visible/near-infrared spectra that suggest enrichment of olivine. Collectively, patterns in major element chemistry and volatile release data indicate two distinctive volatile reservoirs in Martian soils: (1) amorphous components in the sand-sized fraction (represented by Bagnold) that are Si-enriched, hydroxylated alteration products and/or H2O- or OH-bearing impact or volcanic glasses and (2) amorphous components in the fine fraction (<40m; represented by Rocknest and other bright soils) that are Fe, S, and Cl enriched with low Si and adsorbed and structural H2O. Plain Language Summary The Bagnold dune field is an active sand field with moving dunes and sits between the landing site of the Curiosity rover and rocks of interest higher up on Mount Sharp. When passing through the dune field, we used all of Curiosity's instruments to measure the chemistry, mineralogy, and grain size of sands in the Bagnold dune field in order to figure out where they came from, how the sands are transported, and what volatile materials (like water) lie within Martian soils. We found that the Bagnold sand dunes are very well sorted; no dusty materials are found within them, in stark contrast to soils seen previously with Curiosity and with rovers at other landing sites. We found that the coarser sand grains are enriched in the volcanic minerals olivine and pyroxene, confirming a prediction from orbit that wind-related activity seems to concentrate these phases. We also found that the dunes were much lower in water and other volatile elements like sulfur and chlorine versus all previous Mars soils. Using a combination of the rover's sieving system and chemical measurement tools, we figured out that two types of materials host water. In the first type of material, common in these sands, water is low in abundance (similar to 1%), very tightly bound to the grains, and is not released until temperatures >200 degrees C. In the second type of material, water is higher in abundance (2%) and more easily released by heating. Sieved water-bearing fine materials may be a useful resource for human explorers.

Loess is an unique record of the paleoclimate of the Quaternary. Because it is directly deposited from the atmosphere, it can be used as a proxy for wind speed and circulation patterns. It can also be directly dated using luminescence. The site of the loess being investigated for this paper is PrimelTrégastel (Brittany), which lies in north-western France of the shore to the English Channel. The English Channel may be one of the sources for loess of the last glaciation, the Wichselian, and is the reason for choosing Primel-Trégastel to investigate. It is the purpose of this paper to investigate the climate of the time the loess was formed at Primel-Trégastel using grain-size distribution analysis, as well as comparing its properties to other loess sites in north-western Europe. The results show that the loess of Primel-Trégastel is coarse and have a relatively high sand content. That may imply that the loess was deposited during cold and arid conditions by high wind speeds, and at that it may have had a relatively close source. The results also exhibit cycles in the coarseness of the grain-size, indicative of the climate varying between cold and relatively warmer, resulting in relatively higher and lower wind speeds respectively. The loess of Nantois and Pegwell Bay are also relatively coarse, and the loess of Pegwell Bay also have a high sand content. The loess of Nussloch was in comparison more unlike the one of Primel-Trégastel, possibly due to the lack of a local source of sand at Nussloch.

An investigation of austenite grain growth of two bearing steel grades; 100Cr6 and100CrMnMoSi8-4-6 is performed. Austenitization treatments were performed between 860°C and 1200 °C for 5 minutes to 5 hours and the grain size was determined for each sample.Grain boundary etching was carried out using a water based, picric-acid etchant. Generally,100CrMnMoSi8-4-6 was harder to etch than 100Cr6. Therefore, a precipitation heattreatment was performed in order to facilitate etching of prior austenite grain boundaries in100CrMnMoSi8-4-6. The precipitation treatment was found to be effective. However, theprecipitation heat treatment was not suitable for 100Cr6 as the grain size increased duringthe precipitation heat treatment.Light optical microscope equipped with a camera was utilized to take micrographs for grainsize evaluation. Jeffries' standard procedure according to ASTM E112-96 was used tomeasure the grain size. The results shows that the austenite grain size increases withtemperature and time as expected. The experimental data was fitted to a well-known graingrowth model. The model only worked for the temperatures investigated and could not bemade to fit different temperatures.Local grain size variation was studied and its influence on fatigue properties was evaluated.The result showed that variation in local grain size can significantly alter the fatigueproperties. The findings are only theoretical and have not been tested practically.Two different spheroidization heat treatments and one homogenization heat treatmentwere performed. Both spheroidization heat treatments investigated exhibited similar grainsize. The homogenization heat treatment reduced the local grain size variation.Homogenization treatment prior to the spheroidization treatments did not increase ordecrease the grain size. The long heating, holding and cooling times in the secondspheroidization heat treatment is probably the reason for the lack of grain refinementcompared to the first spheroidization heat treatment. The grains had time to grow to theinitial austenite grain size during each cycle.