Inducer dynamics full-flow, full-admission hydraulic turbine drive Interim report for tasks 1, 2, and 3

Hydrodynamical and mechanical design layout for two-speed hydraulic turbine inducer, computer simulation of pumping system and test facility performance, and study of demonstration uni

Contrasting photosynthetic characteristics of forest vs. savanna species (Far North Queensland, Australia)

Forest and savanna are the two dominant vegetation types of the tropical regions with very few tree species common to both. At a broad scale, it has long been recognised that the distributions of these two biomes are principally governed by precipitation and its seasonality, but with soil physical and chemical properties also potentially important. For tree species drawn from a range of forest and savanna sites in tropical Far North Queensland, Australia, we compared leaf traits of photosynthetic capacity, structure and nutrient concentrations. Area-based photosynthetic capacity was higher for the savanna species with a steeper slope to the photosynthesis ← nitrogen (N) relationship compared with the forest group. Higher leaf mass per unit leaf area for the savanna trees derived from denser rather than thicker leaves and did not appear to restrict rates of light-saturated photosynthesis when expressed on either an area or mass basis. Median ratios of foliar N to phosphorus (P) were relatively high (>20) at all sites, but we found no evidence for a dominant P limitation of photosynthesis for either forest or savanna trees. A parsimonious mixed-effects model of area-based photosynthetic capacity retained vegetation type and both N and P as explanatory terms. Resulting model-fitted predictions suggested a good fit to the observed data (R2 Combining double low line 0.82). The model's random component found variation in area-based photosynthetic response to be much greater among species (71% of response variance) than across sites (9%). These results suggest that, on a leaf-area basis, savanna trees of Far North Queensland, Australia, are capable of photosynthetically outperforming forest species at their common boundaries.This work was supported by the UK Natural Environment Research Council (reference NE/F002165/1), a Royal Society of London UK–Australia Exchange Award to Jon Lloyd, and the Australian Research Council (reference DP0986823)

Three-Body Dynamics and Self-Powering of an Electrodynamic Tether in a Plasmasphere

The dynamics of an electrodynamic tether in a three-body gravitational environment are investigated. In the classical two-body scenario the extraction of power is at the expense of orbital kinetic energy. As a result of power extraction, an electrodynamic tether satellite system loses altitude and deorbits. This concept has been proposed and well investigated in the past, for example for orbital debris mitigation and spent stages reentry. On the other hand, in the three-body scenario an electrodynamic tether can be placed in an equilibrium position fixed with respect to the two primary bodies without deorbiting, and at the same time generate power for onboard use. The appearance of new equilibrium positions in the perturbed three-body problem allow this to happen as the electrical power is extracted at the expenses of the plasma corotating with the primary body. Fundamental differences between the classical twobody dynamics and the new phenomena appearing in the circular restricted three-body problem perturbed by the electrodynamic force of the electrodynamic tether are shown in the paper. An interesting application of an electrodynamic tether placed in the Jupiter plasma torus is then considered, in which the electrodynamic tether generates useful electrical power of about 1 kW with a 20-km-long electrodynamic tether from the environmental plasma without losing orbital energy

Survey of highly non-Keplerian orbits with low-thrust propulsion

Celestial mechanics has traditionally been concerned with orbital motion under the action of a conservative gravitational potential. In particular, the inverse square gravitational force due to the potential of a uniform, spherical mass leads to a family of conic section orbits, as determined by Isaac Newton, who showed that Kepler‟s laws were derivable from his theory of gravitation. While orbital motion under the action of a conservative gravitational potential leads to an array of problems with often complex and interesting solutions, the addition of non-conservative forces offers new avenues of investigation. In particular, non-conservative forces lead to a rich diversity of problems associated with the existence, stability and control of families of highly non-Keplerian orbits generated by a gravitational potential and a non-conservative force. Highly non-Keplerian orbits can potentially have a broad range of practical applications across a number of different disciplines. This review aims to summarize the combined wealth of literature concerned with the dynamics, stability and control of highly non-Keplerian orbits for various low thrust propulsion devices, and to demonstrate some of these potential applications

A Review of Basic Energy Reconstruction Techniques in Liquid Xenon and Argon Detectors for Dark Matter and Neutrino Physics Using NEST

Detectors based upon the noble elements, especially liquid xenon as well as liquid argon, as both single- and dual-phase types, require reconstruction of the energies of interacting particles, both in the field of direct detection of dark matter (Weakly Interacting Massive Particles or WIMPs, axions, etc.) and in neutrino physics. Experimentalists, as well as theorists who reanalyze/reinterpret experimental data, have used a few different techniques over the past few decades. In this paper, we review techniques based on solely the primary scintillation channel, the ionization or secondary channel available at non-zero drift electric fields, and combined techniques that include a simple linear combination and weighted averages, with a brief discussion of the applications of profile likelihood, maximum likelihood, and machine learning. Comparing results for electron recoils (beta and gamma interactions) and nuclear recoils (primarily from neutrons) from the Noble Element Simulation Technique (NEST) simulation to available data, we confirm that combining all available information generates higher-precision means, lower widths (energy resolution), and more symmetric shapes (approximately Gaussian) especially at keV-scale energies, with the symmetry even greater when thresholding is addressed. Near thresholds, bias from upward fluctuations matters. For MeV-GeV scales, if only one channel is utilized, an ionization-only-based energy scale outperforms scintillation; channel combination remains beneficial. We discuss here what major collaborations use.Comment: 42 Pages, 2 Tables, 11 Figures, 13 Equation

Carbon stable isotope analysis of cereal remains as a way to reconstruct water availability: preliminary results

Reconstructing past water availability, both as rainfall and irrigation, is important to answer questions about the way society reacts to climate and its changes and the role of irrigation in the development of social complexity. Carbon stable isotope analysis of archaeobotanical remains is a potentially valuable method for reconstructing water availability. To further define the relationship between water availability and plant carbon isotope composition and to set up baseline values for the Southern Levant, grains of experimentally grown barley and sorghum were studied. The cereal crops were grown at three stations under five different irrigation regimes in Jordan. Results indicate that a positive but weak relationship exists between irrigation regime and total water input of barley grains, but no relationship was found for sorghum. The relationship for barley is site-specific and inter-annual variation was present at Deir ‘Alla, but not at Ramtha and Khirbet as-Samra

Impact testing to determine the mechanical properties of articular cartilage in isolation and on bone

The original publication is available at www.springerlink.comNon peer reviewedPostprin

Analysis of Capture Trajectories into Periodic Orbits About Libration Points

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77033/1/AIAA-33796-456.pd

A fresh approach to investigating CO2 storage: Experimental CO2-water-rock interactions in a low-salinity reservoir system

The interactions between CO2, water and rock in low-salinity host formations remain largely unexplored for conditions relevant to CO2 injection and storage. Core samples and sub-plugs from five Jurassic-aged Surat Basin sandstones and siltstones of varying mineralogy have been experimentally reacted in low-salinity water with supercritical CO2 at simulated in situ reservoir conditions (P=12MPa and T=60°C) for 16days (384h), with a view to characterising potential CO2-water-rock interactions in fresh or low-salinity potential siliclastic CO2 storage targets located in Queensland, Australia. CO2-water-rock reactions were coupled with detailed mineral and porosity characterisation, obtained prior to and following reaction, to identify changes in the mineralogy and porosity of selected reservoir and seal rocks during simulated CO2 injection. Aqueous element concentrations were measured from fluid extracts obtained periodically throughout the experiments to infer fluid-rock reactions over time. Fluid analyses show an evolution of dissolved concentration over time, with most major (e.g. Ca, Fe, Si, Mg, Mn) and minor (e.g. S, Sr, Ba, Zn) components increasing in concentration during reaction with CO2. Similar trends between elements reflect shared sources and/or similar release mechanisms, such as dissolution and desorption with decreasing pH. Small decreases in concentration of selected elements were observed towards the end of some experiments; however, no precipitation of minerals was directly observed in petrography. Sample characterisation on a fine scale allowed direct scrutiny of mineralogical and porosity changes by comparing pre- and post-reaction observations. Scanning electron microscopy and registered 3D images from micro-computed tomography (micro-CT) indicate dissolution of minerals, including carbonates, chlorite, biotite members, and, to a lesser extent, feldspars. Quantitative mineral mapping of sub-plugs identified dissolution of calcite from carbonate cemented core, with a decrease in calcite content from 17vol.% to 15vol.% following reaction, and a subsequent increase in porosity of 1.1vol.%. Kinetic geochemical modelling of the CO2-water-rock experiments successfully reproduced the general trends observed in aqueous geochemistry for the investigated major elements. After coupling experimental geochemistry with detailed sample characterisation and numerical modelling, expected initial reactions in the near-well region include partial dissolution and desorption of calcite, mixed carbonates, chloritic clays and annite due to pH decrease, followed in the longer-term by dissolution of additional silicates, such as feldspars. Dissolution of carbonates is predicted to improve injectivity in the near-well environment and contribute to the eventual re-precipitation of carbonates in the far field