Clay minerals and sedimentary basin history

Clay minerals in the mud and soil that coat the Earth's surface are part of a clay cycle that breaks down and creates rock in the crust. Clays generated by surface weathering and shallow diagenetic processes are transformed into mature clay mineral assemblages in the mudrocks found in sedimentary basins. During metamorphism, the release of alkali elements and boron from clay minerals generates magmas that are subsequently weathered and recycled, representing the magma-to-mud pathway of the clay cycle. Volcanogenic clay represents an important but hitherto underestimated proportion of recycled clay. Within sedimentary basins, immature clays are transformed to mature and supermature clay assemblages by a series of reactions that generally obey the Ostwald Step Rule. Bedding-parallel microfabric generated by these reactions produce significant changes in the physical properties of deeply buried mudrocks. Clay minerals react to form equilibrium assemblages in 1 x 104 years in some hydrothermal systems, but immature clays may survive for up to 2 x 109 years in mid-continental rift basins. Clay mineral assemblages and the b cell dimension of K-white mica can be used to infer the geotectonic settings of sedimentary basins

Coding of geodesics on some modular surfaces and applications to odd and even continued fractions

The connection between geodesics on the modular surface $\operatorname{PSL}(2,{\mathbb Z})\backslash {\mathbb H}$ and regular continued fractions, established by Series, is extended to a connection between geodesics on $\Gamma\backslash {\mathbb H}$ and odd and grotesque continued fractions, where $\Gamma\cong {\Bbb Z}_3 \ast {\Bbb Z}_3$ is the index two subgroup of $\operatorname{PSL}(2,{\mathbb Z})$ generated by the order three elements $\left( \begin{smallmatrix} 0 & -1 \\ 1 & 1 \end{smallmatrix} \right)$ and $\left( \begin{smallmatrix} 0 & 1 \\ -1 & 1 \end{smallmatrix} \right)$, having an ideal quadrilateral as fundamental domain. A similar connection between geodesics on $\Theta\backslash {\mathbb H}$ and even continued fractions is discussed in our framework, where $\Theta$ denotes the Theta subgroup of $\operatorname{PSL}(2,{\mathbb Z})$ generated by $\left( \begin{smallmatrix} 0 & -1 \\ 1 & 0 \end{smallmatrix} \right)$ and $\left( \begin{smallmatrix} 1 & 2 \\ 0 & 1 \end{smallmatrix} \right)$.Comment: 19 pages, minor typos corrected and clarifications added in the published versio

Abundance and behavioural ecology of bottlenose dolphins (Tursiops truncatus) in the Marlborough Sounds, New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Conservation Biology at Massey University

In order to survive, animals require both food and protection from predators. These ecological factors are major determinants in habitat selection and social interactions. Determining the causes of habitat selection and examining the behavioural ecology of marine mammals is often a difficult task. In the ever-changing marine environment, factors such as shifts in prey availability, turbidity, sea surface temperature, and salinity result in a highly dynamic ecosystem that influences distribution. This research's primary focus was to establish baseline information on the behavioural ecology of bottlenose dolphins, Tursiops truncatus in and around the Marlborough Sounds, New Zealand. Boat based surveys, photo-identification, and group focal follows were used to assess spatial distribution, abundance, home range, and social interactions. Boat based surveys were conducted from 2003 to 2005. Photo-identification data collected from 1997 to 2005 were used in analysis. Uniquely marked individuals (n = 335) were sighted throughout the Marlborough Sounds and long-term site fidelity was observed among members in this large open population. Aggregations of between 3 to 172 individuals were observed with a median group size of 12. Group size was influenced by the presence of calves, with groups tending to be larger when calves were present. Larger groups were found to rest more than smaller groups and resting occurred less in the spring months. Association patterns revealed long- and short-term preferred associations between individuals throughout the Sounds. Distribution and movement patterns of dolphins showed they used all areas within the Marlborough Sounds. The population of bottlenose dolphins observed in the Marlborough Sounds were found to be semi-resident with 211.5 (C.I. = 195 - 232) individuals utilising the Sounds year round while other individuals were found to migrate in and out of the area on an annual basis. The Marlborough Sounds appear to be only a portion of a much larger home range for this population

SSME turbopump bearing analytical study

Three shuttle pump bearings operating under severe overspeed and shut-down conditions are evaluated. The specific parameters investigated include outer race stresses, cage stresses, cage-race drag, bearing heating, and crush loading. A quasi-dynamic version of the BASDAP computer code was utilized which involved the calculation of ball-race forces (inner and outer), contact pressures, contact dimensions, and contact angles as a function of (1) axial load, (2) radial load, and (3) centrifugal load on the bearing. Generally, radial loads on the order of 13,300 N (3000 pounds) per bearing or 26,700 N (6000 pounds) per bearing pair, could be expected to cause severe problems to any of the bearings with a 17,800 N (4000 pounds) axial load. Further, when possible temperature excursions are considered, even a load of 8900 N (2000 pounds) may be excessive. However, high momentary radial loads with a 3800 N (850 pounds) axial load would not be anticipated to cause catastrophic failure of the fuel pump bearing

High pressure oxygen turbopump bearing cage stability analyses

The low service life of the high pressure oxygen turbopump (HPOTP) bearings used in the space shuttle main engine was examined by use of the Battelle "BASDAP' bearing computer stability model. The dynamic instability of the bearing cage resulted in excessive wear and eventual failure of the unit. By maintaining a cage/race clearance of no more than 0.25 millimeters (0.010 inches), ball/pocket clearance of no less than 0.54 millimeters (0.025 inches), dynamic balancing of the cages, and maintaining adequate lubricant films between the balls and races, cage instability and subsequent bearing degradation can be reduced

Main drivers of the ECB financial accounts and ECB financial strength over the first 11 years

This paper analyses the main drivers of the ECB’s balance sheet and profit and loss account over the first 11 years of the ECB’s existence. Furthermore, the paper assesses the financial strength of the ECB. As monetary policy operations are normally conducted by national central banks under the impulse and instructions from the ECB, the Eurosystem balance sheet is the primary reference for the analysis of Eurosystem monetary policy operations. Three main drivers of the balance sheet and profit and loss account are identified. Firstly, financial market developments and portfolio management decisions imply changes in the value of the foreign reserve and own funds portfolios, which represent a substantial part of the balance sheet (with the share of own funds becoming increasingly larger over the period under review). At the same time, the profit and loss account depends to an important degree on interest income and expenses, realised gains and losses, and write-downs on these portfolios. Secondly, strong banknote demand has gradually increased the size of the balance sheet since the euro changeover in 2002. Banknotes in circulation also provide a strong base for seigniorage income, which is an important item of the profit and loss account. Thirdly, the liquidity-providing operations in foreign currency, which the Eurosystem has undertaken since 2007 in response to the fi nancial crisis, increased significantly the size of the ECB’s (and the Eurosystem’s) balance sheet. In terms of income and expenses, these operations were rather immaterial at the level of the ECB, although the income generated was substantial at the Eurosystem level. The ECB has remained financially strong over the 11-year period. Factors that support the financial position are strong legislative provisions on e.g. independence and income, the use of financial buffers, seigniorage as a reliable income source and an effective loss-coverage mechanism. JEL Classification: D21, D92, E22, E52central bank balance sheet, central banking, financial accounts, financial strength