The free energy balance equation applied to gyrokinetic instabilities, the effect of the charge flux constraint, and application to simplified kinetic models

The free energy balance equation for gyrokinetic fluctuations is derived and applied to instabilities. An additional term due to electromagnetic sources is included. This can provide a simpler way to compute the free energy balance in practical applications, and is also conceptually clarifying. The free energy balance, by itself, is not sufficient to determine an eigenfrequency. The preceding results are derived in general geometry. The charge flux constraint in gyrokinetics can provide a necessary additional relation, and the combination of these two can be equivalent to a dispersion relation. The charge flux constraint can prevent the appearance of an unstable eigenmode even though the free energy balance would allow strongly growing fluctuations. The application of these concepts to simplified kinetic models in simplified geometry is also indicated.Comment: 5 page

Heterogeneous uptake of the C1 to C4 organic acids on a swelling clay mineral

Mineral aerosol is of interest due to its physiochemical impacts on the Earth's atmosphere. However, adsorbed organics could influence the chemical and physical properties of atmospheric mineral particles and alter their impact on the biosphere and climate. In this work, the heterogeneous uptake of a series of small organic acids on the swelling clay, Na-montmorillonite, was studied at 212 K as a function of relative humidity (RH), organic acid pressure and clay mass. A high vacuum chamber equipped with a quadrupole mass spectrometer and a transmission Fourier transform infrared spectrometer was used to detect the gas and condensed phases, respectively. Our results show that while the initial uptake efficiency was found to be independent of organic acid pressure, it increased linearly with increasing clay mass. Thus, the small masses studied allow access to the entire surface area of the clay sample with minimal effects due to surface saturation. Additionally, results from this study show that the initial uptake efficiency for butanoic (butyric) acid on the clay increases by an order of magnitude as the RH is raised from 0% to 45% RH at 212 K while the initial uptake efficiency of formic, acetic and propanoic (propionic) acids increases only slightly at higher humidities. However, the initial uptake efficiency decreases significantly in a short amount of time due to surface saturation effects. Thus, although the initial uptake efficiencies are appropriate for initial times, the fact that the uptake efficiency will decrease over time as the surface saturates should be considered in atmospheric models. Surface saturation results in sub-monolayer coverage of organic acid on montmorillonite under dry conditions and relevant organic acid pressures that increases with increasing humidity for all organic acids studied. Additionally, the presence of large organic acids may slightly enhance the water content of the clay above 45% RH. Our results indicate that heterogeneous uptake of organic acids on swelling clay minerals provides an important irreversible heterogeneous sink for these species

Evidence for early Mesoproterozoic arc magmatism in the Musgrave Block, central Australia: Implications for Proterozoic crustal growth and tectonic reconstructions of Australia

The Musgrave Block in central southern Australia separates the dominantly Paleoproterozoic North Australian Craton from the Late Archean to early Mesoproterozoic Gawler Craton in southern Australia. Geochemical and Nd isotopic data from ∼1.59–1.55-Ga felsic rocks in the Mann Ranges suggest that the early history of the Musgrave Block was linked to the development of subduction along the northern margin of the Gawler Craton. Characteristic geochemical patterns of these felsic rocks include negative anomalies in Nb, Ti, and Y and are accompanied by steep light rare earth element patterns and comparatively juvenile Nd isotopic compositions (εNd(1550) values from -1.2 to 0.9). The geochemical and isotopic signatures of these early Mesoproterozoic felsic rocks have similarities with island arc systems involving residual Ti-bearing minerals and garnet. We propose that the 1.59–1.55-Ga arclike rocks in the Musgrave Block indicate the presence of an active margin between the North Australian Craton and the South Australian Craton, with subsequent suturing of the Australian continent during the early Mesoproterozoic. The existence of arclike magmatism in the Musgrave Block during the early Mesoproterozoic suggests a period of major crustal growth in the Australian Proterozoic that has important implications for current Proterozoic reconstructions of Australia and Australia’s fit within the supercontinent Rodinia.B. P. Wade, K. M. Barovich, M. Hand, I. R. Scrimgeour and D. F. Clos

Evidence for early Mesoproterozoic arc magmatism in the Musgrave Block, central Australia: Implications for Proterozoic crustal growth and tectonic reconstructions of Australia

The Musgrave Block in central southern Australia separates the dominantly Paleoproterozoic North Australian Craton from the Late Archean to early Mesoproterozoic Gawler Craton in southern Australia. Geochemical and Nd isotopic data from ∼1.59–1.55-Ga felsic rocks in the Mann Ranges suggest that the early history of the Musgrave Block was linked to the development of subduction along the northern margin of the Gawler Craton. Characteristic geochemical patterns of these felsic rocks include negative anomalies in Nb, Ti, and Y and are accompanied by steep light rare earth element patterns and comparatively juvenile Nd isotopic compositions (εNd(1550) values from -1.2 to 0.9). The geochemical and isotopic signatures of these early Mesoproterozoic felsic rocks have similarities with island arc systems involving residual Ti-bearing minerals and garnet. We propose that the 1.59–1.55-Ga arclike rocks in the Musgrave Block indicate the presence of an active margin between the North Australian Craton and the South Australian Craton, with subsequent suturing of the Australian continent during the early Mesoproterozoic. The existence of arclike magmatism in the Musgrave Block during the early Mesoproterozoic suggests a period of major crustal growth in the Australian Proterozoic that has important implications for current Proterozoic reconstructions of Australia and Australia’s fit within the supercontinent Rodinia.B. P. Wade, K. M. Barovich, M. Hand, I. R. Scrimgeour and D. F. Clos

Magnetohydrodynamics (MHD) Engineering Test Facility (ETF) 200 MWe power plant. Design Requirements Document (DRD)

A description and the design requirements for the 200 MWe (nominal) net output MHD Engineering Test Facility (ETF) Conceptual Design, are presented. Performance requirements for the plant are identified and process conditions are indicated at interface stations between the major systems comprising the plant. Also included are the description, functions, interfaces and requirements for each of these major systems. The lastest information (1980-1981) from the MHD technology program are integrated with elements of a conventional steam electric power generating plant