The story of the "cylindrical saxophone" started with Benade (1988). The basic idea is that when the length of the missing part of a truncated cone is smaller than the wavelength, and therefore smaller than the length of the truncated cone, the behavior of a conical reed instrument has similarities with that of a cylindrical pipe excited by a reed on its side, at an intermediate location. The s...

Structural analysis and design of efficient pressurized fuselage configurations for the advanced BlendedWing-Body (BWB) flight vehicle is a challenging problem. Unlike a conventional cylindrical pressurized fuselage, stress level in a box type BWB fuselage is an order of magnitude higher, because internal pressure primarily results in bending stress instead of skin-membrane stress. In addition,...

A method for solving the shell-model eigenproblem in a severely truncated space, spanned by properly selected correlated states obtained by partitioning the full configuration space, is proposed. The method describes in a practically exact way the low energy spectroscopic properties of nuclei, as exemplified in schematic models. The applicability of the method to heavy nuclei as well as in cont...

We have investigated the segregation of Pt atoms to the surfaces of Pt-Re nanoparticles using the Monte Carlo method and modified embedded-atom method potentials that we have developed for Pt-Re alloys. The Pt(75)Re(25) nanoparticles (containing from 586 to 4,033 atoms) are assumed to have disordered fcc configurations and cubo-octahedral shapes (terminated by [111] and [100] facets), while the...

The problem of a thin spherical linearly-elastic shell, perfectly bonded to an infinite linearly-elastic medium is considered. A constant axisymmetric stress field is applied at infinity in the matrix, and the displacement and stress fields in the shell and matrix are evaluated by means of harmonic potential functions. In order to examine the stability of this solution, the buckling problem of ...

We present a practical solution to the " sign problem " in the auxiliary field Monte Carlo approach to the nuclear shell model. The method is based on extrapolation from a continuous family of problem-free Hamiltonians. To demonstrate the resultant ability to treat large shell-model problems, we present results for 54 Fe in the full f p-shell basis using the Brown-Richter interaction. We find t...

A method of truncating the large shell model basis is outlined. It relies on the order given by the unperturbed energies of the basis states and on the constancy of their spreading widths. Both quantities can be calculated by a simple averaging procedure. The method is tested in the sd shell where the JT dimensions are of the order of a few thousand. It proves to be very effective in the middle...

We propose a procedure to determine the effective nuclear shell-model Hamiltonian in a truncated space from a self-consistent mean-field model, e.g., the Skyrme model. The parameters of pairing plus quadrupole-quadrupole interaction with monopole force are obtained so that the potential energy surface of the Skyrme HartreeFock + BCS calculation is reproduced. We test our method for N = Z nuclei...

A method of truncating the large shell model basis is outlined. It relies on the order given by the unperturbed energies of the basis states and on the constancy of their spreading widths. Both quantities can be calculated by a simple averaging procedure. The method is tested in the sd shell where the JT dimensions are of the order of a few thousand. It proves to be very effective in the middle...

A preliminary study of structural concepts for noncircular fuselage configurations is presented. For an unconventional flying-wing type aircraft, in which the fuselage is inside the wing, multiple fuselage bays with non-circular sections need to be considered. In a conventional circular fuselage section, internal pressure is carried efficiently by a thin skin via hoop tension. If the section is...