Selection and Scheduling of Advanced Missions for NASA Using 0-1 Integer Linear Programming

A 0-1 integer linear programme for the selection and scheduling of US National Aeronautics and Space Administration (NASA) missions over a long planning horizon is presented. This model was formulated to allow a higher-level user-interaction with an advanced missions database currently being developed. The model implicitly considers the multi-objective nature of the problem, which results from the desire to maximize benefits in several categories as well as from the desire to minimize cost. In addition, the model allows the planner much flexibility in the selection process. This is accomplished by allowing the planner the ability to specify long- or short-term budget constraints, precursor/follow-on mission requirements, or any number of other idiosyncratic constraints which might be of importance in the decision process. Small example problems are solved in order to illustrate the approach, and areas for further research are discussed.     

Radiation-induced fermion resonance

The Dirac equation is solved for two novel terms which describe the interaction energy between the half-integral spin of a fermion and the classical, circularly polarized, electromagnetic field. A simple experiment is suggested to test the new terms and the existence of radiation-induced fermion resonance.     

The optical-mechanical analogy in general relativity: Exact Newtonian forms for the equations of motion of particles and photons

In many metrics of physical interest, the gravitational field can be represented as an optical medium with an effective index of refraction. We show that, in such a metric, the orbits of both massive and massless particles are governed by a variational principle which involves the index of refraction and which assumes the form of Fermat's principle or of Maupertuis's principle. From this variational principle we derive exact equations of motion of Newtonian form which govern both massless and massive particles. These equations of motion are applied to some problems of physical interest.     

Assignment of the 5,6-Double-Bond Configuration in Iloprost and Isoiloprost from 13C-NMR Shifts Determined by 2D Methods

The configurations of the 5,6-double bond in the carbacyclins iloprost ( 3 ; (E)) and isoiloprost ( 4 ; (Z)) are based on a complete assignment of the ¹³C and ¹H resonances determined by 1D and 2D ¹³C-NMR and ¹H-NMR methods.     

Synthesis of substituted 5-aminomethyl tetrahydro-isoquinolines and dihydro-isoindoles

The synthesis of ten substituted aminomethylene tetrahydro-isoquinolines is described, proceeding in eight steps from 5-hydroxyisoquinoline via reductive amination of N-Boc tetrahydro-isoquinoline 5-carboxaldehyde. Likewise, reductive amination was used to prepare four substituted dihydro-isoindoles from the corresponding aldehyde. The dihydro-isoindole ring system was conveniently accessed via a 2+2+2 cycloaddition reaction.     

The effect of dipole-dipole interaction on zero-THz frequency polarisation

The effect of intramolecular dipole-dipole interaction on polarisation at frequencies from 0 – 10¹² Hz in dipolar media is investigated using a numerical solution of the Sturm-Liouville eigenvalue problem to which the governing Smoluchowski equation reduces. The results of Budó for the long-wavelength limit are extended to all frequencies up to the far infrared, where the predominant inertial effects are treated using a preliminary first-order correction. The numerical method of Pryce may be used to investigate much more realistic interaction potentials than the simple harmonic and cosine form considered by Budó. These simple forms are, however, sufficient to indicate that the integrated absorption intensity per molecule in the far infrared is very sensitive to dipole-dipole interaction and relative hydrodynamic drag on both interacting groups. Applications of the theory to the disordered solid and nematic phases are considered.     

A study of the oxidation of vegetable oils by inverse gas chromatography

Summary Inverse gas chromatography is shown to be suitable for the study of the oxidation of vegetable oils. With air as carrier gas characteristic plots of retention index versus time are obtained for hydroxylic test solutes that are consistent with the oxidation behaviour of vegetable oils. Shifts of retention are found to be accompanied by changes of column efficiency due to the oxidative crosslinking of polyunsaturated vegetable oils. The technique also leads to useful information concerning the oxidation of antioxidant inhibited systems. Presented at the 15th International Symposium on Chromatography, Nürnberg, October 1984