Nuclear orientation and coincidence studies of118I and118Cs isotopes

Gamma-gamma coincidence and on-line nuclear orientation experiments have been done on¹¹⁸I^g(2–),¹¹⁸I^m(7–),¹¹⁸Cs^g(2–) and¹¹⁸Cs^m(8–). The activities were produced by 175 MeV^32,34S beams on⁹³Nb and the products passed through an isotope separator. Nuclear moments for the¹¹⁸I isomers are deduced. The decay scheme of¹¹⁸Te is given and various spin assignments made, particularly 1944.3 KeV (3–) and 957.3 KeV (o⁺). Equilibrium distortion of the¹¹⁸I ground state is discussed briefly.     

Radio frequency excited waveguide CO2 lasers on sequence-band transitions

2 lasers based on either a quartz or an alumina waveguide were studied on the 00°2 - [10°1,02°1]_I,II sequence bands. A compact multisegment RF excitation with capacitive coupling was used for pumping the gain section of the laser waveguide. The use of a separate intracavity hot CO₂ waveguide suppresses the regular-band transitions. The quartz waveguide laser has a total of 62 lines lasing on both the 9.4 and 10.4 μm sequence bands. The alumina waveguide laser has 40 lines lasing on the 10.4 μm sequence band. These lasers can be either pulsed or continuous-wave (CW) operated on the selected line without a line jumping problem. Received: 29 September 1997/Revised version: 2 December 1997     

A pattern-directed approach to FMS scheduling

Scheduling in flexible manufacturing systems (FMS) must take into account the shorter lead time, the multiprocessing environment, and the dynamically changing states. In this paper, a pattern-directed approach is presented which incorporates a nonlinear planning method developed in the artificial intelligence field. The scheduling system described here is knowledge-based and utilizes both forward-and backward-chaining for generating schedules (treated as state-space plans). The pattern-directed approach is dynamically adjustable and thus can handle scheduling requirements unique to the FMS environment, such as dynamic scheduling, failure-recovery scheduling, or prioritized scheduling for meeting deadlines.     

Effects of fiber orientation on the stress distribution in model composites

A Raman-mechanical technique was used to study the relationship between stress distribution and fiber orientation in model composites. Our experimental data generally were consistent with most simplistic mechanical models. A more complete analysis, using the Eshelby equivalent inclusion method, fitted our experimental data exceptionally well. For large applied strains, compressive failure occurred for fibers which were oriented at high angles relative to the draw direction. This occurred because of the lateral shrinkage associated with the matrix when the sample was stretched. The effect of fiber end geometry on the stress distribution for these misaligned fibers was the same as observed earlier. Tapered-end fibers generally carried loads more efficiently in composites than blunt-end fibers.     

E0 transitions in the mid-shell even-even Xe nuclides: Decay of 31-s124Cs to levels of124Xe

The results of measurement of the gamma-ray and conversion-electron singles and coincidence spectra from the decay of 31-s¹²⁴Cs to levels of¹²⁴Xe are reported. Previously unobserved E0 transitions are identified and the X factors associated with their decay deduced. These results are discussed along with results of measurements on the structure of adjacent Xe nuclides     

The failure of specular limit formulae for Kirchhoff integrals associated with Gaussian surfaces with ocean-like spectra

We analyse the use of asymptotic expansions for Kirchhoff and related integrals for scattering from Gaussian surfaces, for the limit of high Rayleigh parameter (high frequency, near-normal incidence). An extension of the traditional analysis of this type has been given very recently by Tatarskii and Tatarskii. We show that such expansions are invalid for typical frequencies of interest (L-, C-, X-band radar) when the correlation function arises from a class of spectra with ocean-like characteristics, and present alternative numerical results for such integrals. The near-normal-incidence behaviour of these integrals can in fact be fitted quite well by a parametrized Gaussian, but with parameters not directly related to the distribution of slopes. This suggests that measurements of the cross section near normal incidence may not be the reliable indicator of surface-slope parameters that they are thought to have been. These results also illustrate the dangers of using asymptotic expansions in cases where the relevant parameters are insufficiently large for the asymptotic method to be valid.