Abundance and Partitioning of OH in a High-pressure Magmatic System: Megacrysts from the Monastery Kimberlite, South Africa

Concentrations of OH, and major and trace elements were determined in a suite of mantle-derived megacrysts that represent the crystallization products of a kimberlite-like magma at ~5 GPa and ~1400–1100°C. OH concentrations, determined by single-crystal Fourier transform infrared spectroscopy, display the following ranges (ppmw H2O): olivine 54–262, orthopyroxene 215–263, garnet 15–74, clinopyroxene 195–620, and zircon 28–34. High OH concentrations in olivine imply mantle conditions of origin, with limited H loss during ascent. OH is consistently correlated with megacryst composition, exhibiting trends with Mg-number that are similar to those of other minor and trace elements and indicating a record of high-pressure magmatic evolution. H substitution is not coupled to minor elements in olivine, but may be in ortho- and clinopyroxene. The OH–Mg-number trends of garnet and clinopyroxene show inflections related to co-precipitation of ilmenite, suggesting minor element (Ti) influence on OH partitioning. During differentiation, relative OH enrichment in clinopyroxene and olivine is consistent with proportional dependence on water activity, whereas that in garnet suggests a higher power-law dependence and/or influence of temperature. Inter-mineral distribution coefficients for OH between cpx, opx, olivine and zircon are thus constant, whereas partitioning between these minerals and garnet shows a factor 4–10 variation, correlated regularly with composition (and temperature). Calculation of solid–melt partition coefficients for H at 5 GPa over a range of magmatic evolution from 1380 to 1250°C yields: ol 0·0053–0·0046, opx 0·0093–0·0059, cpx 0·016–0·013, gt 0·0014–0·0003, bulk (garnet lherzolite–melt) 0·0063–0·0051. These are consistent with experimental studies and similar to values inferred from mid-ocean ridge basalt geochemistry, confirming the moderate incompatibility of H in mantle melting

Investigation of thermionic energy conversion final report, 9 jul. - 9 sep. 1962

Refractory ceramic oxide for thermionic diode

Structure of the Alkali-metal-atom-Strontium molecular ions: towards photoassociation and formation of cold molecular ions

The potential energy curves, permanent and transition dipole moments, and the static dipolar polarizability, of molecular ions composed of one alkali-metal atom and a Strontium ion are determined with a quantum chemistry approach. The molecular ions are treated as effective two-electron systems and are treated using effective core potentials including core polarization, large gaussian basis sets, and full configuration interaction. In the perspective of upcoming experiments aiming at merging cold atom and cold ion traps, possible paths for radiative charge exchange, photoassociation of a cold Lithium or Rubidium atom and a Strontium ion are discussed, as well as the formation of stable molecular ions

New Attractors and Area Codes

In this note we give multiple examples of the recently proposed New Attractors describing supersymmetric flux vacua and non-supersymmetric extremal black holes in IIB string theory. Examples of non-supersymmetric extremal black hole attractors arise on a hypersurface in $WP^{4}_{1,1,1,1,2}$. For flux vacua on the orientifold of the same hypersurface existence of multiple basins of attraction is established. It is explained that certain fluxes may give rise to multiple supersymmetric flux vacua in a finite region on moduli space, say at the Landau-Ginzburg point and close to conifold point. This suggests the existence of multiple basins for flux vacua and domain walls in the landscape for a fixed flux and at interior points in moduli space.Comment: 16 pages, harvmac. v2: acknowledgement update

High efficiency compound semiconductor concentrator photovoltaics

Special emphasis was given to the high yield pilot production of packaged AlGaAs/GaAs concentrator solar cells, using organometallic VPE for materials growth, the demonstration of a concentrator module using 12 of these cells which achieved 16.4 percent conversion efficiency at 50 C coolant inlet temperature, and the demonstration of a spectral splitting converter module that achieved in excess of 20 percent efficiency. This converter employed ten silicon and ten AlGaAs cells with a dichroic filter functioning as the beam splitter. A monolithic array of AlGaAs/GaAs solar cells is described

Master agreement task order 2 - Analyses and limited evaluations of payload and landing system structures for the survivable soft landing of instrument payloads

Computer programs for analysis and evaluation of payload and landing system structures for soft landing of instrument package

The Semiclassical and Quantum Regimes of Superradiant Light Scattering from a Bose-Einstein Condensate

We show that many features of the recent experiments of Schneble et al. [D. Schneble, Y. Torii, M. Boyd, E.W. Streed, D.E. Pritchard and W. Ketterle, Science vol. 300, p. 475 (2003)], which demonstrate two different regimes of light scattering by a Bose-Einstein condensate, can be described using a one-dimensional mean-field quantum CARL model, where optical amplification occurs simultaneously with the production of a periodic density modulation in the atomic medium. The two regimes of light scattering observed in these experiments, originally described as ``Kapiza-Dirac scattering'' and ``Superradiant Rayleigh scattering'', can be interpreted as the semiclassical and quantum limits respectively of CARL lasing.Comment: 10 pages, 5 figures - to appear in Journal of Optics

Implications of bio-efficacy and persistence of insecticides when indoor residual spraying and longlasting insecticide nets are combined for malaria prevention.

Bio-efficacy and residual activity of insecticides used for indoor residual spraying (IRS) and long-lasting insecticide nets (LLINs) were assessed against laboratory-reared and wild populations of the malaria vector, Anopheles arabiensis in south eastern Tanzania. Implications of the findings are examined in the context of potential synergies and redundancies where IRS and LLINs are combined. METHODS: Bioassays were conducted monthly for six months on three LLIN types (Olyset(R) PermaNet 2.0(R),and Icon Life(R)) and three IRS treatments (2 g/m2 pirimiphos-methyl, 2 g/m2 DDT and 0.03 g/m2 lambda-cyhalothrin, sprayed on mud walls and palm ceilings of experimental huts). Tests used susceptible laboratory-reared An. arabiensis exposed in cones (nets and IRS) or wire balls (nets only). Susceptibility of wild populations was assessed using WHO diagnostic concentrations and PCR for knock-down resistance (kdr) genes. IRS treatments killed [greater than or equal to] 85% of mosquitoes exposed on palm ceilings and [greater than or equal to] 90% of those exposed on mud walls, but up to 50% of this toxicity decayed within 1-3 months, except for DDT. By 6th month, only 7.5%, 42.5% and 30.0% of mosquitoes died when exposed to ceilings sprayed with pirimiphos-methyl, DDT or lambda-cyhalothrin respectively, while 12.5%, 36.0% and 27.5% died after exposure to mud walls sprayed with the same insecticides. In wire-ball assays, mortality decreased from 98.1% in 1st month to 92.6% in 6th month in tests on PermaNet 2.0(R), from 100% to 61.1% on Icon Life(R) and from 93.2% to 33.3% on Olyset(R) nets. In cone bioassays, mortality reduced from 92.8% in 1st month to 83.3% in 6th month on PermaNet 2.0(R), from 96.9% to 43.80% on Icon Life(R) and from 85.6% to 14.6% on Olyset(R). Wild An. arabiensis were 100% susceptible to DDT, 95.8% to deltamethrin, 90.2% to lambda cyhalothrin and 95.2% susceptible to permethrin. No kdr gene mutations were detected. CONCLUSIONS: In bioassays where sufficient contact with treated surfaces is assured, LLINs and IRS kill high proportions of susceptible An. arabiensis mosquitoes, though these efficacies decay gradually for LLINs and rapidly for IRS. It is, therefore, important to always add intact nets in sprayed houses, guaranteeing protection even after the IRS decays, and to ensure accurate timing, quality control and regular re-spraying in IRS programmes. By contrast, adding IRS in houses with intact LLINs is unlikely to improve protection relative to LLINs alone, since there is no guarantee that unfed vectors would rest long enough on the sprayed surfaces, and because of the rapid IRS decay. However, there is need to clarify these effects using data from observations of free flying mosquitoes in huts. Physiological susceptibility of An. arabiensis in the area remains 100% against DDT, but is slightly reduced against pyrethroids, necessitating caution over possible spread of resistance. The loss of LLIN toxicity, particularly Olyset(R) nets suggests that protection offered by these nets against An. arabiensis may be primarily due to physical bite prevention rather than insecticidal efficacy

Rethinking the concept of small-scale mining for technologically advanced raw materials production

This is the final version. Available from Elsevier via the DOI in this record.The purpose of this paper is conceptual analysis and critique, informing development of a modern technologically-advanced small-scale mining (SSM) concept. The need for SSM has recently been articulated in a European mining policy context. In an attempt to secure access to minerals, European strategy includes the development of new approaches to the extraction of resources from ore deposits, including by SSM operations. However, the application of traditional thinking and definitions of small-scale mining to a European context is problematic, such that the evolution of modern smaller scale mining also requires re-thinking of the underpinning concepts. We discuss various company structures, scales of mining and their specific features. We differentiate SSM from “artisanal small-scale mining” (ASM) and discuss its relationship to “large-scale mining” (LSM). From this analysis, we distill the key features and criteria of SSM and raise important questions concerning social and environmental sustainability in relation to SSM. We suggest that greater definition of what constitutes technological small-scale mining in a European context will substantially improve further research in the development of mining solutions and contribute to the discussion on the future of mining both within and outside of Europe.European Commissio