Procedure for utilizing the lift and thrust forces of ornithopters

This procedure is distinguished by two beating wings which together describe, in space, a succession of interlaced triangles. On these wings, whose incidence varies automatically, identical forces are exerted: simultaneous lift and thrust when they make their descent, which is inclined toward the front of the craft, and lift alone when they make their ascent, which is inclined toward the rear of the craft and follows a slide horizontal movement. A mechanical device makes these movements possible. It includes: two wings with hollow profiles, connected by a framework located above a rigid frame and attached to it by bars with joints. These bars are moved with control rods which gear down the drive force. A mechanism with elastic bands or springs automatically varies the incidence of the wings

A model of the spatial and temporal variation of the Uranus thermal structure

Seasonal variability of the temperature structure of Uranus is modeled for all latitudes in the .0004 to 2 bar pressure range in anticipation of the Voyager encounter in January 1986. Atmospheric heating in the model results on the one hand from an internal heat source and, on the other hand, from absorption of solar energy by methane and by non-conservative aerosols located between the 0.5 and 2 bar levels. Various cases for the behavior of the internal heat flux are investigated, such as constant with latitude or constrained to yield a time-averaged thermal emission independent of latitude. Meridional transport of heat in the stably stratified atmosphere is not taken into account. The results indicate that the Voyager encounter time, very small north-south temperature asymmetry should be expected. Moreover, the northern hemisphere, although not illuminated, should emit as much energy (within one percent) as the southern hemisphere at this date. At a given latitude, extreme temperatures are reached at the equinoxes. At the poles, seasonal amplitudes of about 10 K in the upper stratosphere and 6 K at the 0.6 bar level are predicted, and the variation with time of the emission to space is found to be at most 20 percent. The atmosphere of Uranus appears to be characterized by very long radiative response times (mainly due to its cold temperature) which inhibit the large seasonal variations that one could otherwise expect in view of the high obliquity of the planet and its long orbital period

A Time-Dependent Model of HD209458b

We developed a time-dependent radiative model for the atmosphere of HD209458b to investigate its thermal structure and chemical composition. Time-dependent temperature profiles were calculated, using a uniform zonal wind modelled as a solid body rotation. We predict day/night temperature variations of 600K around 0.1 bar, for a 1 km/s wind velocity, in good agreement with the predictions by Showman & Guillot (2002). On the night side, the low temperature allows the sodium to condense. Depletion of sodium in the morning limb may explain the lower than expected abundance found by Charbonneau et al (2002).Comment: 2 pages, LaTeX with 1 EPS figure embedded, using newpasp.sty (supplied). To appear in the proceedings of the XIXth IAP colloquium "Extrasolar Planets: Today and Tomorrow" held in Paris, France, 2003 June 30 -- July 4, ASP Conf. Se

Spatial variation of the thermal structure of Jupiter's atmosphere

The radiative seasonal model described by Bezard and Gautier for the case of Saturn was adapted to Jupiter. That the atmosphere is radiatively controlled above the 500 mb pressure level and that the temperature at the radiative-convective boundary level is constant for all latitudes is assumed. An internal heat source and absorption by methane and aerosols contribute to atmospheric heating. Absorption by aerosols was adjusted to give a planetary Bond albedo equal to 0.343. Despite Jupiter's low obliquity, the model predicts seasonal variations of temperature of several degrees for the 1 mb pressure level at mid-latitude regions

Impact of crustal assimilation on the Lesser Antilles arc lava geochemistry

Characterization of the mantle source of arc magmas using the composition of erupted lavas is only possible after the assessment of the effects of crustal assimilation. While the impact of crustal assimilation on continental arc lavas is commonly investigated, it is often ignored or debated in oceanic arcs. Nowhere has the debate been more acute than in the Lesser Antilles arc which is characterised by extreme ranges in geochemistry from typical oceanic arc to continental crust-like compositions. Given the oceanic provenance of the arc, these geochemical features can be inherited either from subducted sediments, or from crustal contamination by continental sediments intercalated in the arc crust. In this thesis, the problem is reassessed using a whole rock-to sub-grain scale trace element and isotopic (Sr-Nd-Hf-Pb- O isotopes) investigation of volcanic rocks from St Lucia Island, thought to encompass most of the arc’s isotopic heterogeneities. In addition, an Os isotopic investigation of some of the most mafic and well constrained lavas from along the arc was performed. New isotopic composition of St Lucia lavas confirm that the island covers most of the arc’s compositional variations. Intra-crystal 87Sr/86Sr heterogeneities as well as the co-variation of lava radiogenic isotopes and trace elements with SiO2 and mineral d18O suggest that crustal assimilation affected lavas as mafic as basaltic andesites and is responsible for the isotopic and trace element heterogeneities observed in the Island. The assimilant is thought to be a mix of detrital and organic sediments, likely to have been part of the sedimentary basin intruded by the arc. Assimilation of sediment is thought to occur in the middle crust of the arc and to be tightly linked with the production of silicic magmas. Sr, Nd, Hf and Pb isotopic compositions of the lavas that avoided significant sediment assimilation suggest that no more than 2% of slab-derived sediment was added to the source of St Lucia magmas. However, an along arc 187Os/188Os investigation suggests that even the most mafic lavas, having escaped sediment assimilation, were modified on their way to the surface by assimilation of the igneous arc roots, possibly a plagioclase-rich cumulate. Care must therefore be applied before characterising the source using mafic lava compositions since this process is thought to modify the Os and Sr isotopes, as well as La/Sm and Sr/Th ratios. This suggests that, in the Lesser Antilles arc, very few lavas preserved their original mantle source characteristics

Analytical Blowup Solutions to the 2-dimensional Isothermal Euler-Poisson Equations of Gaseous Stars

We study the Euler-Poisson equations of describing the evolution of the gaseous star in astrophysics. Firstly, we construct a family of analytical blowup solutions for the isothermal case in R^2. Furthermore the blowup rate of the above solutions is also studied and some remarks about the applicability of such solutions to the Navier-Stokes-Poisson equations and the drift-diffusion model in semiconductors are included. Finally, for the isothermal case, the result of Makino and Perthame for the tame solutions is extended to show that the life span of such solutions must be finite if the initial data is with compact support.Comment: 15 page

Developing Multicultural Self-awareness Through a Transformative Learning Experience

The purpose of this qualitative case study was to explore the ways that a change in perspective can create a better understanding of cultural identity. This study addressed: (1) How does a self-awareness transformative learning experience develop critical cultural competence in career and technical education instructors? (2) How does the practice of critical reflection construct career and technical education instructors’ ability to develop self-awareness of critical cultural competence? (3) How does involvement in critical discourse construct career and technical education instructors’ ability to develop self-awareness of critical cultural competence? A three-phase professional development experience rooted in multicultural education provided key elements of transformative learning

Composition of late summer diet by semi-domesticated reindeer (Rangifer tarandus tarandus) in different grazing areas in northernmost Finland

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Deuterium on Venus: Observations from Earth

In view of the importance of the deuterium-to-hydrogen ratio in understanding the evolutionary scenario of planetary atmospheres and its relationship to understanding the evolution of our own Earth, we undertook a series of observations designed to resolve previous observational conflicts. We observed the dark side of Venus in the 2.3 micron spectral region in search of both H2O and HDO, which would provide us with the D/H ratio in Venus' atmosphere. We identified a large number of molecular lines in the region, belonging to both molecules, and, using synthetic spectral techniques, obtained mixing ratios of 34 plus or minus 10 ppm and 1.3 plus or minus 0.2 ppm for H2O and HDO, respectively. These mixing ratios yield a D/H ratio for Venus of D/H equals 1.9 plus or minus 0.6 times 10 (exp 12) and 120 plus or minus 40 times the telluric ratio. Although the detailed interpretation is difficult, our observations confirm that the Pioneer Venus Orbiter results and establish that indeed Venus had a period in its early history in which it was very wet, perhaps not unlike the early wet period that seems to have been present on Mars, and that, in contrast to Earth, lost much of its water over geologic time