No description available.

We report the discovery and orbit of a new dwarf planet candidate, 2015 RR245, by the Outer Solar System Origins Survey (OSSOS). The orbit of 2015 RR245 is eccentric (e = 0.586), with a semimajor axis near 82 au, yielding a perihelion distance of 34 au. 2015 RR245 has g - r = 0.59 +/- 0.11 and absolute magnitude H-r = 3.6 +/- 0.1; for an assumed albedo of p(V) = 12%, the object has a diameter of similar to 670. km. Based on astrometric measurements from OSSOS and Pan-STARRS1, we find that 2015 RR245 is securely trapped on ten-megayear timescales in the 9: 2 mean-motion resonance with Neptune. It is the first trans-Neptunian object (TNO) identified in this resonance. On hundred-megayear. timescales, particles in 2015 RR245-like orbits depart and sometimes return to the resonance, indicating that 2015 RR245 likely forms part of the long-lived metastable population of distant TNOs that drift between resonance sticking and actively scattering via gravitational encounters with Neptune. The discovery of a 9: 2 TNO stresses the role of resonances in the long-term evolution of objects in the scattering disk. and reinforces the view that distant resonances are heavily populated in the current solar system. This object further motivates detailed modeling of the transient sticking population.

A thesis submitted to the Faculty of Science at the University of the Witwatersrand, in fulfilment of the requirements for the degree of Doctor of Philosophy in Geology. Johannesburg 2017. / The Magondi Belt is a NE-trending Palaeoproterozoic mobile belt, composed of a succession of supracrustal metasediments and minor metavolcanics that is subdivided into the Deweras, Lomagundi and Piriwiri Groups. The Magondi Belt is located in north-west Zimbabwe and is bounded on its eastern flank by the Archaean Zimbabwe Craton and the Pan-African Zambezi Belt to the north. A connection between the Superior and Zimbabwe cratons has previously been made based on similarly aged dyke swarms across the two cratons. This matching magmatic barcode implies that the Superior and Zimbabwe cratons rifted away from one another circa 2.26 Ga based on the ages obtained for the Deweras lavas and the Chimbadzi Hill mafic intrusion. It was into this continental rift margin that the Magondi Supergroup sediments were deposited. The majority of the detrital and xenocrystic zircon ages from the Deweras Group are Archaean (2.86 to 2.63 Ga, with some inherited grains as old as 3.34 Ga); although a maximum depositional age of circa 2.29 Ga for the Deweras Group sedimentary rocks has been determined. Unconformably overlying these sediments, within an environment gradually transitioning from a passive margin into a back-arc basin environment, is the Lomagundi Group. These shallow marine sediments are then followed by those of the Piriwiri Group, deposited within a deeper water environment. Deposition of these two groups is constrained between 2.20 and 2.16 Ga, but may have continued up until the termination of the Magondi orogeny circa 1.99 Ga. According to the currently accepted model, the Magondi orogeny is the result of the Zimbabwe Craton colliding with an unknown continental mass, “Terra Incognita”, resulting in the formation of a Palaeoproterozoic Andean-type magmatic arc along the western margin of the Zimbabwe Craton (the arc is typified by the 2.06 - 2.02 Ga granites and gneisses of the Dete-Kamativi Inlier), which was subsequently thrust over the margin of the Zimbabwe Craton, the consequence of which was a Himalayan-style collision that resulted in high-grade metamorphism and the formation of collisional granitoids (e.g. the Hurungwe Granite) circa 1.99 Ga ago. It has also been established that the Dete-Kamativi Inlier, which flanks the western margin of the Zimbabwe Craton, is an extension of the Magondi Belt. Detrital zircons from paragneisses of the Malaputese Formation have ages ranging from 2.8 to 2.5 Ga, with the youngest grains constraining the maximum depositional age to be around 2.3 Ga. Thus, in terms of age and lithology, the correlation of the Malaputese Formation with the Deweras Group (maximum age of 2.29 Ga) is permissible. A south westward extension of 2.06 - 2.02 Ga granitoids – emplaced during the Magondi orogeny – is indicated by a number of localities in north-eastern Botswana and is believed to also be related to the Palaeoproterozoic magmatic arc. This study has recorded the first evidence of Archaean-aged basement within the Dete-Kamativi Inlier. Two orthogneisses with ages of 2.76 and 2.69 Ga provide strong evidence to suggest that the western margin of the Zimbabwe Craton may extend further to the west than previously recognised. It has also been confirmed, based on the recurrence of ~2.64 Ga aged zircons, in addition to older inherited grains ranging from 3.34 to 2.72 Ga, that the crust below the Magondi Belt is Archaean in age. This is not so, however, for the high-grade gneisses in the northern reaches of the Magondi Belt. It has been previously suggested that these supposed basement granites and gneisses represent an Archaean orogeny, but they are in fact Palaeoproterozoic in age, as represented by the syn-to-post-tectonic 2.02 Ga Hurungwe orthogneiss and the 1.95 Ga Kariba Granite. Additionally, a second, 1.96 Ga, orthogneiss contains zircons with younger metamorphic overgrowth rims that are Pan-African in age (545 Ma) and are attributed to the collision between the Kalahari and Congo cratons in the Neoproterozoic. It is therefore apparent that there is not enough evidence to support the existence of an Archaean “Hurungwe orogeny”. The Magondi orogeny was the heat source for a widespread mineralisation and metamorphic event between 2.15 and 2.03 Ga, based on titanite and apatite ages from samples of the Archaean Copper King and Copper Queen Domes within the Magondi Belt. There is also evidence of a second, younger, mineralisation event, which primarily affected both the Dete-Kamativi Inlier and the Choma-Kalomo Block (south east Zambia). U-Pb data on columbite-tantalite grains (corroborated by 40Ar-39Ar dating of mica separates) from tin-bearing pegmatites within both the Choma-Kalomo Block and the Dete-Kamativi Inlier indicates that mineralisation occurred simultaneously within these two terranes between 1.06 and 0.98 Ga. The similarities (particularly with regards to mineralisation), between the Choma-Kalomo Block and the Dete-Kamativi Inlier imply that these two terranes had a shared history, potentially as far back as the Palaeoproterozoic, but were certainly juxtaposed by 1.06 Ga when the pegmatites were emplaced. The previously undated metasediments of the Choma-Kalomo Block have revealed an abundant Palaeoproterozoic component (2.04 - 1.86 Ga), contradicting the prevailing understanding that the Choma-Kalomo Block is solely Mesoproterozoic in age (on account of the granitoids, which were previously dated at 1.37 and 1.18 Ga). The Choma-Kalomo Block was also thought to constitute an exotic terrane with respect to the neighbouring Dete-Kamativi Inlier and Archaean Zimbabwe Craton. Based on the geochronology presented here, a new model is proposed whereby the thinner lithosphere beneath the Choma-Kalomo Block is either a primary feature or one that resulted from subduction erosion and delamination processes associated with the formation of multiple continental margin magmatic arcs. / MT 2017

La chaîne actuelle du Tian Shan (Asie centrale) est considérée comme une conséquence directe de la réactivation d'une ceinture orogénique du Paléozoïque due à la collision Inde-Asie, au Cénozoïque. Un travail détaillé a été réalisé le long du piémont nord de la chaîne en intégrant les observations géologiques de terrain, analyses structurales, profils sismiques, nouvelles mesures des anomalies gravimétriques et des données de forages. Tout d'abord cette étude apporte de nouvelles preuves directes, à différentes échelles, sur l'existence d'un paléo-relief majeur le long du front nord du Tian Shan au cours du Mésozoïque, et plus particulièrement pendant le Jurassique. Deuxièmement, la quantité de raccourcissement calculée à travers cette ceinture de plis et chevauchements nord du Tian Shan est relativement faible et les structures reconnues le long du front de la chaîne présentent une hétérogénéité latérale forte. Ainsi, alors qu’un chevauchement du socle paléozoïque sur les séries sédimentaires mésozoïques et cénozoïques du bassin est remarquablement exposé le long de certaines vallées, d'autres sections montrent que les séries sédimentaires du Trias au Jurassique peuvent être suivies de manière continue, depuis le bassin jusque sur le toit du socle Paléozoïque où ils reposent en discordance relativement haut dans la chaîne. Quatre coupes géologiques ont été construites par l'intégration des données pluridisciplinaires acquises. La restauration de ces coupes montre que les taux de raccourcissement sont inférieurs à 20% et peuvent descendre à un minimum de 6%. Ces observations suggèrent que le piémont nord du Tian Shan est plutôt «jeune» et que la chaîne d’avant pays est encore à un stade primaire de son évolution tectonique. En d'autres termes, le piémont nord du Tian Shan peut être considéré comme un exemple type de front de chaîne immature. / The modern Tian Shan (Central Asia) is considered as a direct consequence of the reactivation of a Paleozoic orogenic belt due to the India – Asia collision, during Cenozoic times. A detailed work has been investigated along the northern piedmont of Tian Shan, integrating the field work, structural analysis, seismic profile data, gravity anomaly measurements and drilled wells. Firstly, this study brings new and direct evidences, at different scales, for the existence of a major paleo-relief along the northern Tian Shan range during Mesozoic, and particularly during Jurassic times. Secondly, the calculated shortening amount in the northern piedmont of Tian Shan is rather small and the structural pattern of its front is heterogeneous along-strike. While, thrusting of the Paleozoic basement on the Mesozoic or Cenozoic sedimentary series of the basin is remarkably exposed along several river valleys, other sections display continuous Triassic to Jurassic sedimentary series from the basin to the range where they unconformably overlie on the Carboniferous basement. Four cross-sections are made by integrating multi-method data, showing that shortening amounts are less than 20% and could be even until to 6%. This suggests that the Tian Shan intracontinental range is rather “young” and still at a primary stage of its tectonic evolution. In other words, its front may be considered as a typical example of an immature range front.

A laboratory was built at Prairie Swine Centre Inc. (PSCI) to study air quality in swine barns and its effect on pigs and people. The first focus of that research program was to design and test a manure handling system to control the air contamination from the excreta. The goal was to get close to zero air contamination from manure with these systems, in order to measure the contamination from other sources, and to also have a range of contamination levels for future health and productivity testing. Two manure handling systems were designed and tested: a washing gutter system with pressurized heated wash water periodically directed across the dunging area, and a washed inclined conveyor belt used directly as a dunging area. Ammonia emissions were used as a measure of the air contamination originating from the excreta in two experimental chambers. Ammonia originates only from the manure and is released quickly from any manure (especially urine) in contact with the air. Both systems were tested with 30 kg pigs at running time intervals of 30, 60 and 120 minutes. Trials lasted one week, with three trials completed at each frequency. The average ammonia emissions from the washing gutter and the conveyor belt systems were 48.7 mg day-1 kgpig-1 and 57.0 mg day-1 kgpig-1, respectively. Even though these emissions were 38% and 47% lower than previous observations from grower-finisher rooms with a pit plug design in the same swine building, both systems failed to give the desired close-to-zero contamination. This means another system will have to be found to totally eliminate air contamination from manure in the chambers when testing for the origin of the individual contaminants. There were no differences at a statistically significant level (P>0.05) between the ammonia emissions from the two manure handling systems or the three frequencies tested. However, the washing gutter system was simpler and easier to run, and is recommended for future studies dealing with the effects of different ranges of air quality on pigs and people.

A laboratory was built at Prairie Swine Centre Inc. (PSCI) to study air quality in swine barns and its effect on pigs and people. The first focus of that research program was to design and test a manure handling system to control the air contamination from the excreta. The goal was to get close to zero air contamination from manure with these systems, in order to measure the contamination from other sources, and to also have a range of contamination levels for future health and productivity testing. Two manure handling systems were designed and tested: a washing gutter system with pressurized heated wash water periodically directed across the dunging area, and a washed inclined conveyor belt used directly as a dunging area. Ammonia emissions were used as a measure of the air contamination originating from the excreta in two experimental chambers. Ammonia originates only from the manure and is released quickly from any manure (especially urine) in contact with the air. Both systems were tested with 30 kg pigs at running time intervals of 30, 60 and 120 minutes. Trials lasted one week, with three trials completed at each frequency. The average ammonia emissions from the washing gutter and the conveyor belt systems were 48.7 mg day-1 kgpig-1 and 57.0 mg day-1 kgpig-1, respectively. Even though these emissions were 38% and 47% lower than previous observations from grower-finisher rooms with a pit plug design in the same swine building, both systems failed to give the desired close-to-zero contamination. This means another system will have to be found to totally eliminate air contamination from manure in the chambers when testing for the origin of the individual contaminants. There were no differences at a statistically significant level (P>0.05) between the ammonia emissions from the two manure handling systems or the three frequencies tested. However, the washing gutter system was simpler and easier to run, and is recommended for future studies dealing with the effects of different ranges of air quality on pigs and people.

Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2010. / Committee Chair: Leamy, Michael; Committee Member: Costello, Mark; Committee Member: Ferri, Aldo. Part of the SMARTech Electronic Thesis and Dissertation Collection.

This thesis investigates the architectural role of green belts and recreational zones as one solution to urban sprawl, ultimately creating healthier, more livable cities. A list of concepts and guidelines will be derived from both historical and modern green belt efforts, for the development of a more livable city in the 21st century. These concepts will then be tested as a tool on the city of Halifax. The concepts and guidelines will be used in the development of a green belt master plan. The plan will connect Halifax through existing and proposed parks and recreation. Secondly, it will develop a series of networks and connections enhancing the ability for alternate methods of transportation into and out of the urban core, facilitated by the design of a pedestrian bridge. Finally, a second design will support the existing program of mountain biking and create a unique architectural cycling experience for both the user and the observer.

No description available.

The Fox River Belt forms a segment of the Circum-Superior Belt that comprises a series of ca. 1900 Ma volcanosedimentary belts located around the margins of the Superior Province. The Fox River Belt is a north-facing homoclinal sequence, composed of a rift-related sedimentary sequence, intercalated with thick sequences of komatiites and tholeiites, and intruded by mafic-ultramafic intrusions. Geological mapping, whole rock geochemistry and S, Nd- and Hf-isotope geochemistry of the magmatic and sedimentary units within the belt were used to obtain a better understanding of the magmatic and tectonic history of the belt and its relation with other segments of the Circum-Superior Belt. The compositional variation observed in the volcanic rocks (19% to 5% MgO) can be accounted for as the product of fractional crystallization. Trace element patterns as well as εNd and εHf values (-4 to +8 and +4 to +18 respectively) indicate that the magmatism within the belt was the product of partial melting of depleted mantle that was locally contaminated with sediments or gneiss. A plume origin for this melting event is proposed based on the high degree of partial melting, the large volume of magma, and the presence of a radiating dyke swarm. The 250 km long Fox River Sill appears to have behaved as a magma conduit during part of its history. Several intervals within the sill show enrichment and depletion of PGE. The KO Zone PGE-Cu-Ni mineralization (up to 5ppm PGE) formed from magmatic sulphides whose tenor was upgraded by the upward percolation of evolved intercumulus magma. Contaminated Lower Intrusions and the lower margin of the Fox River Sill are considered particularly prospective for hosting Ni- Cu-PGE mineralization.