Advanced refractory alloy corrosion loop program quarterly progress report no. 1, quarter ending jul. 15, 1965

Material procurement and quality assurance for advanced refractory alloy corrosion loop progra

Pyrotechnic shock analysis and testing methods

Pyrotechnic shock analysis and testing methods for Ranger and Mariner spacecraft measurement

Centrifugally Obtained Artificial Gravity

Centrifugally obtained artificial gravity effects on space station crew performanc

T-111 Rankine system corrosion test loop, volume 2

For abstract, see N76-18258

Asymmetric hyperbolic L-spaces, Heegaard genus, and Dehn filling

An L-space is a rational homology 3-sphere with minimal Heegaard Floer homology. We give the first examples of hyperbolic L-spaces with no symmetries. In particular, unlike all previously known L-spaces, these manifolds are not double branched covers of links in S^3. We prove the existence of infinitely many such examples (in several distinct families) using a mix of hyperbolic geometry, Floer theory, and verified computer calculations. Of independent interest is our technique for using interval arithmetic to certify symmetry groups and non-existence of isometries of cusped hyperbolic 3-manifolds. In the process, we give examples of 1-cusped hyperbolic 3-manifolds of Heegaard genus 3 with two distinct lens space fillings. These are the first examples where multiple Dehn fillings drop the Heegaard genus by more than one, which answers a question of Gordon.Comment: 19 pages, 2 figures. v2: minor changes to intro. v3: accepted version, to appear in Math. Res. Letter

Tunable cavity resonator with ramp shaped supports

A cavity for a hydrogen maser is described consisting of three parts which provide highly stable mechanical and thermal expansion characteristics for the cavity and ease of tuning. The three parts which are made of a glass ceramic material having a very small thermal expansion coefficient (1) a top plate, (2) a cylinder with three interrupted helical ramps at its bottom, and (3) a base which includes a bottom plate and three ramp lugs on which the helical ramps of the cylinder rest when the cylinder is placed on the base with the bottom plate in the cylinder. Cavity tuning is achieved by rotating the cylinder and thereby raising or lowering it on the base, which results in changing the cylinder volume by changing the distance between the bottom and top plates

Nuclear Aspects of Nucleosynthesis in Massive Stars

Preliminary results of a new set of stellar evolution and nucleosynthesis calculations for massive stars are presented. These results were obtained with an extended reaction network up to Bi. The discussion focuses on the importance of nuclear rates in pre- and post-explosive nucleosynthesis. The need for further experiments to study specific reactions and nuclear properties (optical alpha+nucleus potentials) is emphasized.Comment: 6 pages, 2 figures; invited talk, to appear in the Proceedings of the Int. Conf. "Structure of the Nucleus at the Dawn of the Century", May 2000, Bologna, Ital

Nucleosynthesis in massive stars revisited

We have performed the first calculations to follow the evolution of all stable nuclei and their radioactive progenitors in a finely-zoned stellar model computed from the onset of central hydrogen burning through explosion as a Type II supernova. Calculations were done for 15, 20, and 25 solar masses Pop I stars using the most recently available set of experimental and theoretical nuclear data, revised opacity tables, and taking into account mass loss due to stellar winds. Here results are presented for one 15 solar masses model.Comment: 4 pages, 1 figure; needs espcrc1.sty; talk at "Nuclei in the Cosmos 2000", Aarhus, Denmark, June 2000; will appear in Nucl. Phys.