Miracle-dz/UniFAR-FTUs huggingface dataset:
Turbulent shear flow in a rapidly rotating spherical annulus

Title of dissertation: TURBULENT SHEAR FLOW IN A RAPIDLY ROTATING SPHERICAL ANNULUS Daniel S. Zimmerman, Doctor of Philosophy, 2010 Dissertation directed by: Professor Daniel P. Lathrop Department of Physics This dissertation presents experimental measurements of torque, wall shear stress, pressure, and velocity in the boundary-driven turbulent flow of water between concentric, independently rotating spheres, commonly known as spherical Couette flow. The spheres’ radius ratio is 0.35, geometrically similar to that of Earth’s core. The measurements are performed at unprecedented Reynolds number for this geometry, as high as fifty-six million. The role of rapid overall rotation on the turbulence is investigated. A number of different turbulent flow states are possible, selected by the Rossby number, a dimensionless measure of the differential rotation. In certain ranges of the Rossby number near state borders, bistable co-existence of states is possible. In these ranges the flow undergoes intermittent transitions between neighboring states. At fixed Rossby number, the flow properties vary with Reynolds number in a way similar to that of other turbulent flows. At most parameters investigated, the large scales of the turbulent flow are characterized by system-wide spatial and temporal correlations that co-exist with intense broadband velocity fluctuations. Some of these wave-like motions are identifiable as inertial modes. All waves are consistent with slowly drifting large scale patterns of vorticity, which include Rossby waves and inertial modes as a subset. The observed waves are generally very energetic, and imply significant inhomogeneity in the turbulent flow. Increasing rapidity of rotation as the Ekman number is lowered intensifies those waves identified as inertial modes with respect to other velocity fluctuations. The turbulent scaling of the torque on inner sphere is a focus of this dissertation. The Rossby-number dependence of the torque is complicated. We normalize the torque at a given Reynolds number in the rotating states by that when the outer sphere is stationary. We find that this normalized quantity can be considered a Rossby-dependent friction factor that expresses the effect of the self-organized flow geometry on the turbulent drag. We predict that this Rossby-dependence will change considerably in different physical geometries, but should be an important quantity in expressing the parameter dependence of other rapidly rotating shear flows. TURBULENT SHEAR FLOW IN A RAPIDLY ROTATING SPHERICAL ANNULUS
A simplified extension of the conventional theory of arching in soils

Abstract A general formulation is presented for the analysis of arching in soils as an extension of the conventional shear plane approach, in which the slip surfaces within the soil mass are considered as vertical planes. Such an assumption results in a low estimate of the design load on the yielding buried structure because of a considerable separation between the assumed vertical slip surfaces and the actual curved slip surfaces. The arching theory presented in this paper overcomes this limitation of the conventional theory by assuming inclined slip surfaces close to the actual slip surfaces. Based on this concept, an analytical expression for the vertical stress on the yielding structure is derived; a special case of this general expression reduces to the conventional expression. The variation of the vertical stress on the yielding structure with depth has been presented graphically along with a comparison with the conventional vertical shear plane approach. It is observed that the amount of arching increases with increase in the ratio of depth to width of the yielding structure as reported in the literature.
Evaluation of Linear and Non-Linear Downscaling Methods in Terms of Daily Variability and Climate Indices: Surface Temperature in Southern Ontario and Quebec, Canada

Abstract We downscaled atmospheric reanalysis data using linear regression and Bayesian neural network (BNN) ensembles to obtain daily maximum and minimum temperatures at ten weather stations in southern Quebec and Ontario, Canada. Performance of the linear and non-linear downscaling models was evaluated using four different sets of predictors, not only in terms of their ability to reproduce the magnitude of day-to-day variability (i.e., “weather,” mean absolute error between the daily values of the predictand(s) and the downscaled data) but also in terms of their ability to reproduce longer time scale variability (i.e., “climate,” indices of agreement between the predictand's observed annual climate indices and the corresponding downscaled values). The climate indices used were the 90th percentile of the daily maximum temperature, 10th percentile of the daily minimum temperature, number of frost days, heat wave duration, growing season length, and intra-annual temperature range. Our results show that the non-linear models usually outperform their linear counterparts in the magnitude of daily variability and, to a greater extent, in annual climate variability. In particular, the best model simulating weather and climate was a BNN ensemble using stepwise selection from 20 reanalysis predictors, followed by a BNN ensemble using the three leading principal components from the aforementioned predictors. Finally, we showed that, on average, the first three indices presented higher skills than the growing season length, number of frost days, and the heat wave duration.
THE SOCIO-ECONOMIC IMPORTANCE AND STATUS OF POPULATIONS OF BOSWELLIA PAPYRIFERA (DEL.) HOCHST. IN NORTHERN ETHIOPIA: THE CASE OF NORTH GONDER ZONE

ABSTRACT Boswellia papyrifera (Del.) Hochst, is a deciduous multipurpose tree growing in different parts of Ethiopia that provides oleo-gum—frankincense—from its stem. The species holds great actual and potential socio-economic, cultural and environmental importance locally, nationally and internationally. Despite its importance, various anthropogenic and natural factors are causing heavy pressure on the welfare of its populations and hampering regeneration. This study, which was carried out at two sites in North Gonder Zone, northern Ethiopia reports on: • its socio-economic importance: as a source of employment, income, revenue, and other goods and environmental services; • the status of its populations: soil seed bank, density, frequency, DBH. height and population structure; and • factors threatening its populations: human-induced fire, clearing of trees for crop cultivation, browsing and trampling. Recommendations to address the problems include: • making an inventory of the woodland resources with emphasis on the gum and resin producing species; • disseminating information and encouraging gum and resin collection in areas as yet untapped; • improving the harvesting and marketing of the produce.
Age of the Glen Dessary Syenite, Inverness-shire: diachronous Palaeozoic metamorphism Across the Great Glen

Synopsis Apparently igneous zircons from the Glen Dessary syenite complex give concordant U-Pb ages averaging 456 ± 5 Ma which is taken to date crystallization. The complex was deformed and metamorphosed to amphibolite facies subsequent to emplacement so that this age is a maximum for these orogenic events in the western Moine Series. Other age data indicate that amphibolite facies conditions associated with pegmatite emplacement continued until ca. 430 Ma contrasting with the north-east Highlands where tectonism and metamorphism was completed by 460 Ma ago. The disparity between hornblende and mica K-Ar ages suggests that cooling from 500 to 300°C took about 20 Ma. Higher blocking temperatures are indicated for U-Pb in monazite and sphene than for U-Pb in apatite.
2.62 Ga high‐temperature metamorphism in the central part of the Eastern Dharwar Craton: implications for late Archaean tectonothermal history

Aluminous metasediments occurring in the central part of the Eastern Dharwar Craton (EDC), southern India, develop contrasting mineral assemblages in closely spaced domains. Detailed petrographic, mineral chemical and geothermobarometry showed ‘peak’ metamorphic conditions of 780–820 °C and ~5 kbar that resulted in partial melting of biotite‐bearing protoliths. Initial bulk compositional heterogeneity and different degrees of melt extraction produced diverse restitic mineral assemblages. P–T pseudosections, constructed from effective bulk composition, and consideration of the sequence of mineral reactions, deduced from textural criteria, define a nearly isobaric heating–cooling P–T trajectory. Monazite in the metasediments has a detrital core age of 3161 ± 78 Ma and a metamorphic age of 2625 ± 26 Ma (EPMA chemical age), which is the first record of a pre‐2500 Ma high temperature–low pressure metamorphism event in the EDC. Based on age contemporaneity with the 2.7–2.62 Ga hot juvenile magmas of tonalite–trondhjemite–granodiorite (TTG)‐greenstone accretion and the deduced P–T history, we conclude that heat advecting from rising TTG magmas and mafic magmas (greenstones) as a consequence of mantle melting, resulted in a hot transient mid‐crust during a major late Archaean tectonothermal event in the Eastern Dharwar Craton. All the phenomena are consistent with a recently proposed model involving an arc setting during ridge subduction and consequent opening of a slab window. This study therefore provides new constraints on the thermal evolution of the Eastern Dharwar Craton. Copyright © 2011 John Wiley & Sons, Ltd.
Probabilistic identification of underground soil stratification using cone penetration tests

This paper develops Bayesian approaches for underground soil stratum identification and soil classification using cone penetration tests (CPTs). The uncertainty in the CPT-based soil classification using the Robertson chart is modeled explicitly in the Bayesian approaches, and the probability that the soil belongs to one of the nine soil types in the Robertson chart based on a set of CPT data is formulated using the maximum entropy principle. The proposed Bayesian approaches contain two major components: a Bayesian model class selection approach to identify the most probable number of underground soil layers and a Bayesian system identification approach to simultaneously estimate the most probable layer thicknesses and classify the soil types. Equations are derived for the Bayesian approaches, and the proposed approaches are illustrated using a real-life CPT performed at the National Geotechnical Experimentation Site (NGES) at Texas A&M University, USA. It has been shown that the proposed approaches prope.
Tectonic motion and deformation from satellite laser ranging to LAGEOS

Satellite laser ranging (SLR) to LAGEOS acquired during the period 1978–1988 has been analyzed to yield estimates of tectonic motion for 22 laser tracking stations situated on seven major plates. The analysis is based on the precise modeling of the orbit dynamics of LAGEOS and includes the determination of other geodynamic and nonconservative force model parameters involved in the orbit determination problem at the centimeter level. Site velocities were recovered from station positions determined each calendar quarter using a network adjustment procedure which maintains the reference frame. Within the stable interior of tectonic plates, the recovered motions indicate good agreement with existing estimates of stress fields, particularly across northern Europe, the eastern Pacific, and in the Basin and Range province of North America. A comparison of the intersite motions for stations centrally located on separate plates between SLR and those implied by the NUVEL 1 geologic motion model yield a strong positive correlation of 0.989 and a 3–7% scale difference which may be attributable to recent changes in relative velocities or geologic time scale uncertainties. Sites located at or within 250 km of convergent plate boundaries have additional components of motion, indicating a need for further tectonic modeling beyond that provided by simple rigid plate motions. For lines crossing the north Atlantic, the San Andreas fault, and within the Basin and Range province, the geodesic rates determined by SLR are in good agreement with those determined by very long baseline interferometry, an alternative space geodetic technique.
Drought indices and their application to East Africa

This study analysed and modified (where necessary) the properties of three drought indices: the Palmer drought severity index (PDSI), the Bhalme–Mooley index (BMI) and the standardized precipitation index (SPI). We modified the original PDSI's recursive formula, potential runoff, and Z index, which produced more realistic results than the original PDSI (designed for the USA) for East Africa. We improved the SPI by first using a plotting position formula designed for the Pearson type III (P3) distribution to transform the ‘smoothed’ precipitation data into non‐exceedance probabilities, which we then transformed into standard P3 variates by the regional flood index method. The modified SPI depicted East Africa's drought conditions more accurately than the original SPI. Using the three indices and East Africa as a case example, we identified eight assessment criteria to determine the most appropriate index for detecting drought events on a regional basis. BMI produced results that are highly correlated to those of the modified PDSI, which suggested that precipitation alone could explain most of the variability of East African droughts. Furthermore, among the three indices, SPI is more appropriate for monitoring East African droughts because it is more easily adapted to the local climate, has modest data requirements, can be computed at almost any time scale, provides relatively consistent power spectra spatially, has no theoretical upper or lower bounds, and is easy to interpret. Copyright © 2003 Royal Meteorological Society
Isothermal plateau fission‐Track age for a paleomagnetic excursion in the Mamaku Ignimbrite, New Zealand, and implications for Late Quaternary stratigraphy

Mamaku Ignimbrite, the youngest of the large, welded ignimbrite sheet-forming eruptions from the Taupo Volcanic Zone in New Zealand, is dated at 230±12 ka by the isothermal plateau fission-track (ITPFT) method on glass. This age is older and more precise than that indicated by previous studies, requiring the revision of loess/paleosol coverbed chronologies. The eruption occurred during a paleomagnetic excursion allowing the ignimbrite to be easily distinguished from other eruptive events by paleomagnetic methods. This excursion is one of the few such events recorded in igneous rocks in the Southern Hemisphere, may be widely recorded in New Zealand, and is now temporally well constrained.
Simulated climatology and evolution of aridity in the 21st century

Future changes in aridity, defined as the ratio of annual precipitation to potential evapotranspiration (PET), are analyzed using simulations from the Community Earth System Model (CESM) Large Ensemble (LE) and the phase 5 of the Coupled Model Intercomparison Project (CMIP5) during the period 1980–2080. Both CESM and CMIP5 ensembles can reproduce the observed temporal and spatial variability of aridity. On the interannual time scale, annual average PET is sensitive to the variability of relative humidity, net surface energy flux, and surface air temperature, while the precipitation variability is the dominant component of annual average aridity sensitivity. For the long‐term trends, differences between the two ensembles illustrate that the impact of the internal variability is smaller than that of the model structural uncertainty with the trends from the CMIP5 ensemble of models having a much larger spread than those from the single‐model CESM‐LE. The annual mean aridity averaged over global land increases (becomes drier) by 6.4% in 2055–2080 relative to 1980–2005. Aridity trends differ by region in the ensemble mean. In the future, increasing precipitation leads to decreasing aridity over northwest China and central (or tropical) Africa, while decreasing precipitation leads to drying (increasing aridity) in the subtropics, northern and southern Africa, and the Amazon. Increases in PET can lead to increasing aridity even in regions with increasing precipitation.
Basin evolution, diagenesis and uranium mineralization in the Paleoproterozic Thelon Basin, Nunavut, Canada

The Paleoproterozoic (Statherian) Thelon Basin is located in the Churchill Province of the Canadian Shield, formed following the Trans‐Hudson Orogeny. Basin formation followed an interval of felsic volcanism and weathering of underlying bedrock. The diagenetic evolution of the Thelon lasted about one billion years and was punctuated by fluid movement influenced by tectonic events. Early quartz cements formed in well‐sorted, quartz‐rich facies during diagenetic stage 1; fluids in which these overgrowths formed had δ18O values near 0‰ (Vienna Standard Mean Ocean Water). Uranium‐rich apatite cement (P1) also formed during diagenetic stage 1 indicating that oxygenated, uranium‐bearing pore water was present in the basin early in its diagenetic history. Syntaxial quartz cement (Q1) formed in water with δ18O from −4 to −0.8‰ in diagenetic stage 2. Diagenetic stage 3 occurred when the Thelon Formation was at ca. 5 km depth, and was marked by extensive illitization, alteration of detrital grains, and uranium mineralization. Basin‐wide, illite crystallized at ∼200 °C by fluids with δ18O values of 5–9‰ and δD values of −60 to −31‰, consistent with evolved basinal brines. Tectonism caused by the accretion of Nena at ca. 1600 Ma may have provided the mechanism for brine movement during deep burial. Diagenetic stage 4 is associated with fracturing and emplacement of mafic dikes at ca. 1300 Ma, quartz cement (Q3) in fractures and vugs, further illitization, and recrystallization of uraninite (U2). Q3 cements have fluid inclusions that suggest variable salinities, δ18O values of 1.5–9‰, and δD values of −97 to −83‰ for stage 4 brines. K‐feldspar and Mg‐chlorite formed during diagenetic stage 5 at ca. 1000 Ma in upper stratigraphic sequences, and in the west. These phases precipitated from low‐temperature, isotopically distinct fluids. Their distribution indicates that the basin hydrostratigraphy remained partitioned for >600 Ma.
Airborne geophysical surveying for hazardous waste site characterization on the Oak Ridge Reservation, Tennessee

Airborne geophysical methods that were developed for mineral and petroleum exploration can, with some modification, be applied to environmental problems where large areas must be characterized. A helicopter survey that deployed magnetic, electromagnetic, and radiometric sensors carried out one of the first large‐scale airborne environmental surveys at a U.S. government facility at Oak Ridge, Tennessee in 1993–1994. The survey included testing of a new airborne electromagnetic system designed specifically for environmental applications and for controlled field tests of magnetic systems. Helicopter‐borne magnetic measurements were capable of discriminating groups of as few as ten metallic 208-liter (55-gallon) storage drums under representative field conditions. Magnetic and electromagnetic sensors were able to distinguish groups of metal‐filled waste disposal trenches within disposal sites, but were unable to resolve individual trenches. Electromagnetic data proved to be the most effective airborne techniq.
Business Dynamics, Regulation and Performance

Building on an earlier study of patterns on firm entry, exit growth and survival based on new data from Eurostat covering nine European Union member countries (Brandt, 2004), this paper takes a closer look at the role of policies and institutions for firm entry and survival and at the link between new firm creation and economic performance. The earlier study revealed that firm entry rates, i.e. the number of new firms in a market in relation to all active enterprises, were particularly high in Information and Communication (ICT) related industries in recent years. This lends some support to the idea present in some theories of economic growth that new firms are important for the development and implementation of new technologies. This paper takes a closer look at the relationship between firm entry and economic performance. Results reveals that high rates of firm entry tend to coincide with rapid productivity, output and employment growth, especially in the ICT related services . Dynamique de l'entreprise, reglementation et performance S'appuyant sur une etude anterieure concernant les profils d'entree, de sortie, de croissance et de survie des entreprises, elle-meme fondee sur de nouvelles donnees d'Eurostat portant sur neuf pays membres de l'Union europeenne (Brandt, 2004), le present rapport examine de plus pres le role des politiques et des institutions dans l'entree sur le marche et la survie des entreprises, ainsi que le lien entre la creation de nouvelles entreprises et les performances economiques. L'etude initiale revelait que les taux d'entree des entreprises, c'est-a-dire le nombre de nouvelles entreprises en proportion de l'ensemble des entreprises en activite sur un marche, avaient ete particulierement eleves dans les branches d'activite liees a l'information et aux communications (TIC) ces dernieres annees. Cela tend a confirmer l'idee avancee dans certaines etudes theoriques sur la croissance economique selon laquelle les nouvelles entreprises jouent un role important dans le developpement et la .
Tooth enamel structure in the hyaenid Chasmaporthetes lunensis lunensis from the Late Pliocene of Italy, with implications for feeding behavior

ABSTRACT Hunter-Schreger Bands (HSB) and the outer enamel surface of the teeth of the hunting hyena Chasmaporthetes lunensis lunenesis Del Campana, from Olivola (late Pliocene, Italy) has been analysed. As in the bone crushing hyenas (Crocuta, Hyaena, and Pachycrocuta) C. I. lunensis possesses complex HSB, with both horizontal and vertical components. However the less intense folding of the HSB and the smooth outer enamel surface suggest a more primitive structure than that in the bone crushing hyenas. This is consistent with the hypothesis that Chasmaporthetes was not an extremely specialized bone eater.
The Subtropical Zhujiang (Pearl River) Estuary: Nutrient, Trace Species and Their Relationship to Photosynthesis

Two cruises were undertaken to study the nutrients and trace species and their relation to marine production in the Zhujiang (Pearl River) Estuary, which cover both wet (August–September, 1996) and dry (January–February, 1997) seasons. Concentrations of nutrients (NO3−, NH4+, PO43−, and dissolved SiO2) and other major and trace species (alkalinity, DOC and Al) in the Zhujiang are generally within the range of Chinese rivers and comparable to other large systems, like the Huanghe (Yellow River) and Changjiang (Yangtze River). In the estuary, some species (e.g. SiO2) illustrate a fairly defined relationship with chlorinity, whereas others show considerable remobilization and/or changes in freshwater end-members, owing to the fact that fresh water enters the South China Sea from eight channels with various water flow and different compositions. The incubation experiments using in situ water samples reveal that while phosphate is the limiting element in riverine effluent plume, the photosynthesis turns to be nitrogen and/or silicon limited further offshore on the shelf region. Trace species (e.g. Cu2+and Fe2+) have important impact on the photosynthesis in the Zhujiang Estuary, with Fe2+to be a more limiting element than Cu2+. Atmospheric wet deposition may well stimulate photosynthesis and hence demonstrate a potential link with algal blooms in this area. Atmospheric impact on the photosynthesis increases from estuary toward the interior of South China Sea. The experimental data further suggest that in the turbid region of the Zhujiang Estuary, radiation reduction by suspended materials could be an important issue limiting photosynthesis, although the eutrophication is quite common in coastal environments of China.