199,349 research outputs found
CRYSTAL-CHEMISTRY AND INTRACRYSTALLINE RELATIONSHIPS OF ORTHO-PYROXENE IN A SUITE OF HIGH-PRESSURE ULTRAMAFIC NODULES FROM THE NEWER VOLCANICS OF VICTORIA, AUSTRALIA
No full textA suite of orthopyroxenes from spinel lherzolite xenoliths associated with basanites occurring in the Victorian (Australia) post-Pliocene 'Newer Volcanics' province was investigated by means of a crystal chemical methodology which provides accurate site occupancy and site configuration parameters.
The M1 configuration is essentially constrained by Al(IV) rather than Fe2+. In addition, Fe3+, Cr3+ and Ti4+ are confined to M1 (Molin, 1989) and Al(IV) to TB. M2 is controlled by Fe(M2)2+ half arrow right over half arrow left constrained by (Fe2+ + Ca)M2 > 0.14 atoms per formula unit (p.fu.). Cation substitution in TB and M2 constrains the sum of the volumes of the respective polyhedra V(TB) + V(M2) to remain essentially constant. Therefore, M2 favours the retention of the large Fe2+ up to melting-point, causing nonideality of this iron-depleted orthopyroxene. As a consequence, the investigated orthopyroxene can be considered an ultimate Fe2+ carrier during partial mantle melting
M. Molin (dir), Les Régulations sociales dans l'Antiquité
No full textMartin Paul-Marius. M. Molin (dir), Les Régulations sociales dans l'Antiquité. In: Vita Latina, N°180, 2009. pp. 109-111
Subulura suctoria Molin
No full textSubulura suctoria (Molin) Caprimulgus candicans (Pelzeln), intestine, Rio de Janeiro (Vicente et al. 1995). Superfamily Thelazioidea OerleyPublished as part of Muniz-Pereira, Luís C., Vieira, Fabiano M. & Luque, José L., 2009, Checklist of helminth parasites of threatened vertebrate species from Brazil, pp. 1-45 in Zootaxa 2123 on page 13, DOI: 10.5281/zenodo.18817
Pelecitus helicinus Molin
No full textPelecitus helicinus (Molin) Anodorhynchus hyacinthinus (Latham), tendon of the foot, Mato Grosso do Sul (Vicente et al. 1995).Published as part of Muniz-Pereira, Luís C., Vieira, Fabiano M. & Luque, José L., 2009, Checklist of helminth parasites of threatened vertebrate species from Brazil, pp. 1-45 in Zootaxa 2123 on page 9, DOI: 10.5281/zenodo.18817
Oxyspirura cephaloptera Molin
No full textOxyspirura cephaloptera (Molin) Momotus momota marcgraviana Pinto & Camargo, eyes, Mato Grosso (Vicente et al. 1995).Published as part of Muniz-Pereira, Luís C., Vieira, Fabiano M. & Luque, José L., 2009, Checklist of helminth parasites of threatened vertebrate species from Brazil, pp. 1-45 in Zootaxa 2123 on page 13, DOI: 10.5281/zenodo.18817
Fe2+-Mg order-disorder in orthopyroxene: equilibrium fractionation between the octahedral sites and thermodynamic analysis
No full textThe equilibrium intracrystalline distribution coefficient, k*(D), of Fe* (i.e. Fe2+ + Mn) and Mg between the M1 and M2 sites of three natural nearly binary Fe2+-Mg orthopyroxene crystals (FS14 FS15 and Fs(49)) were determined by annealing experiments at several temperatures between 550 and 1000 degrees C and single crystal X-ray structure refinements. In addition, the X-ray data of an orthopyroxene crystal (Fs(23)) which were collected earlier by Molin et al. (1991) between 700 and 1000 degrees C, were re-refined. The data were processed through two different refinement programs (SHELXL-93 and RFINE90) using both unit and individual weights and also both ionic and atomic scattering factors. The calculated site occupancies were found to agree within their estimated standard errors. However, the use of ionic scattering factors led to significantly better goodness of fit and agreement index, and smaller standard deviations of the site occupancies than those obtained from the use of atomic scattering factors. Furthermore, the weighted refinements yielded significantly smaller standard deviations of the site occupancies than the unweighted refinements even when the same set of reflections was used in the two procedures. The site occupancy data from this study were combined with selected published data to develop expressions of k*(D) as a function of temperature and composition. Calculation of the excess configurational entropy, Delta S-XS, suggests that orthopyroxene should be treated as a two parameter symmetric solution instead of as a "simple mixture" The calculated Delta S-XS values and the excess Gibbs free energy of mixing suggested by available cation exchange data lead to a slightly negative enthalpy of mixing in the orthopyroxene solid solution
Perforated fairings for landing gear noise control
No full textLanding gears of commercial aircraft make an important contribution to total aircraft noise in the approach configuration. Using fairings to shield components from high speed impingement reduces noise. Furthermore, perforating these fairings has been confirmed by flight tests to further enable noise reduction. Following a more fundamental study on the application of perforated fairings, a study has been performed to investigate and optimize the benefits of bleeding air through landing gear fairings. By means of wind tunnel tests, an aerodynamic and acoustic survey has been performed on a simplified generic main landing gear to explore the influence of (perforated) fairings on the lower part of the gear. The results show that for this specific case, the application of impermeable fairings reduces noise in the mid- and high frequency range by shielding sharp edged components from high velocity impingement. However, below 1 kHz the noise is shown to increase significantly. Application of the perforations is shown to diminish this low frequency increase whilst maintaining the reduction in the mid- and high frequency range. The aerodynamic and acoustic measurements point in the direction of the separated flow of the fairings interacting with the downstream gear components responsible for the low frequency noise increase. Bleeding of the air through the fairings reduces the large scale turbulence in the proximity of these components and hence diminishes the low frequency increase. A sharp noise increase is present in the ground view direction at the 500 Hz centred tertsband for the solid fairing, which is confirmed to originate from the articulation link fairing. The flow around the wheels remains largely unaltered by application of the fairings. Furthermore the application of fairings is shown to suppress vortex shedding from the lower part of the main leg. A study on the effectiveness of perforation location reveals that the stagnation area perforations are responsible for most of the low frequency noise decrease. Both articulation link and undertray fairing contribute to the reduction. Exposing the perforate outside the stagnation area induces perforate self-noise, most significantly on the sides of the lower articulation link fairing. Agreeing with previous studies, the phenomenon scales with the local component of the shearing flow velocity and orifice diameter
15. Images et représentations du pouvoir et de l'ordre social dans l'Antiquité, Molin (M.) éd
No full textHinard François. 15. Images et représentations du pouvoir et de l'ordre social dans l'Antiquité, Molin (M.) éd. In: Revue des Études Grecques, tome 115, Juillet-décembre 2002. pp. 819-820
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