On the teaching of the aerodynamic heating problem

The problem of aerodynamic heating, along with some other topics, are lacking in most, if not all, heat transfer textbooks that are used for undergraduate and graduate education. There are many issues in the aerodynamic heating problem that are indeed very important from a convective heat transfer point of view. Although this topic is very important in any low or high speed application, the lack of analytical solutions in heat transfer, compressible flow and/or hypersonic flow textbooks has prompted this study. In practice, poor design and manufacture have led to undesired results, such as space shuttle disasters. Since, over the years, analysis has given way to numerical studies, the instructors do not take the necessary time to go through details. Thus the students just use the results without any awareness of how to get them and the inherent limitations of the analytical solution. The only intent of this paper, therefore, is to present the detailed analytical study that is shown step by step that could be used by heat transfer instructors in their courses and by students in their studies

On the origin and evolution of the material in 67P/Churyumov-Gerasimenko

International audiencePrimitive objects like comets hold important information on the material that formed our solar system. Several comets have been visited by spacecraft and many more have been observed through Earth- and space-based telescopes. Still our understanding remains limited. Molecular abundances in comets have been shown to be similar to interstellar ices and thus indicate that common processes and conditions were involved in their formation. The samples returned by the Stardust mission to comet Wild 2 showed that the bulk refractory material was processed by high temperatures in the vicinity of the early sun. The recent Rosetta mission acquired a wealth of new data on the composition of comet 67P/Churyumov-Gerasimenko (hereafter 67P/C-G) and complemented earlier observations of other comets. The isotopic, elemental, and molecular abundances of the volatile, semi-volatile, and refractory phases brought many new insights into the origin and processing of the incorporated material. The emerging picture after Rosetta is that at least part of the volatile material was formed before the solar system and that cometary nuclei agglomerated over a wide range of heliocentric distances, different from where they are found today. Deviations from bulk solar system abundances indicate that the material was not fully homogenized at the location of comet formation, despite the radial mixing implied by the Stardust results. Post-formation evolution of the material might play an important role, which further complicates the picture. This paper discusses these major findings of the Rosetta mission with respect to the origin of the material and puts them in the context of what we know from other comets and solar system objects

Minimal invasive technique in capitellum fracture treatment

The humeral capitellum fractures are rare, and surgical management of these fractures is difficult. The surgeon must achieve anatomic reconstruction with a reliable fixation allowing mobilization of the joint for early rehabilitation. Arthroscopic approach to capitellum fractures allows visualization of the articular surface without the soft tissue dissection required with open approaches. Here, we present a case of type 1 capitellum fracture of humerus that was fixed through arthroscopic assistance. © 2011, Lippincott Williams & Wilkins