Design methodology for a school prototype: Jean Prouvé’s Jules Ferry School Group in Dieulouard, France, 1952–1953

The catastrophic destruction of buildings in France during World War II demanded that reconstruction become one of the primary objectives in the immediate post-war period. This favoured a culture of experimentation, and created a context for Jean Prouvé to develop designs for school buildings. He developed these designs with a research-based process focusing on technical solutions and their prototypes, and with models whose fundamental premises were rapid and easy assembly-disassembly, lightness and economy. The constant correlation between the projected object and the object created in the workshop shaped the basis for the precision of his designs. This article analyses the methodology followed by Prouvé in the Jules Ferry School Group in Dieulouard, France (1952–1953), in the singular context of the post-war period, illustrating the route followed in developing the model rather than the aesthetics of the building. The prototype used in his schools, and the models generated from this system, demonstrate his architectural methods

On the magnetic field of off-limb spicules

Determining the magnetic field related to solar spicules is vital for developing adequate models of these plasma jets, which are thought to play a key role in the thermal, dynamic and magnetic structure of the Chromosphere. Here we report on the magnetic properties of off-limb spicules in a very quiet region of the solar atmosphere, as inferred from new spectropolarimetric observations in the He I 10830 A triplet obtained with the Tenerife Infrared Polarimeter. We have used a novel inversion code for Stokes profiles caused by the joint action of atomic level polarization and the Hanle and Zeeman effects (HAZEL) to interpret the observations. Magnetic fields as strong as ~40G were detected in a very localized area of the slit, which could represent a possible lower value of the field strength of organized network spicules.Comment: Accepted for publication in ApJ, 24 pages, 5 Figure

Influence of atomic polarization and horizontal illumination on the Stokes profiles of the He I 10830 multiplet

The polarization observed in the spectral lines of the He I 10830 multiplet carries valuable information on the dynamical and magnetic properties of plasma structures in the solar chromosphere and corona, such as spicules, prominences, filaments, emerging magnetic flux regions, etc. Here we investigate the influence of atomic level polarization on the emergent Stokes profiles for a broad range of magnetic field strengths, in both 90 degree and forward scattering geometry. We show that, contrary to a widespread belief, the selective emission and absorption processes caused by the presence of atomic level polarization may have an important influence on the emergent linear polarization, even for magnetic field strengths as large as 1000 G. Consequently, the modeling of the Stokes Q and U profiles should not be done by taking only into account the contribution of the transverse Zeeman effect within the framework of the Paschen-Back effect theory, unless the magnetic field intensity of the observed plasma structure is sensibly larger than 1000 G. We point out also that in low-lying optically thick plasma structures, such as those of active region filaments, the (horizontal) radiation field generated by the structure itself may substantially reduce the positive contribution to the anisotropy factor caused by the (vertical) radiation field coming from the underlying solar photosphere, so that the amount of atomic level polarization may turn out to be negligible. Only under such circumstances may the emergent linear polarization of the He I 10830 multiplet in such regions of the solar atmosphere be dominated by the contribution caused by the transverse Zeeman effect.Comment: Accepted for publication in The Astrophysical Journal (It is tentatively scheduled for the ApJ January 20, 2007 issue