Galactic cosmic ray heavy primary secondary doses

Results of a calculation which estimates the heavy primary secondary doses from cosmic ray interaction data are reported. The incident galactic cosmic ray heavy primary spectrum is represented as the sum of helium, nitrogen, magnesium, and iron components. The incident iron nuclei are allowed to fragment into lesser Z secondaries, which are assumed to travel in the same direction and start with the same energy per nucleon as the interacting primary. The total emergent particle energy spectra and dose are then presented for the galactic heavy primary spectrum incident on aluminum and tissue slabs. The importance of the fragmentation parameters assumed is also evaluated. The total dose from the heavy primaries and their secondaries is found to be reduced by only a factor of two in 20 g/sq cm of shielding

A study of radiation environment in space and its biological effects

Biological effects on man in space resulting from galactic and solar cosmic radiation are discussed. Importance of secondary ions which contribute to galactic cosmic radiation hazards is analyzed. Mathematical model to show rate of production of secondary ions of given atomic number at various points in absorber is presented

Study of radiation hazards to man on extended missions

Radiation hazards on extended manned space flight

A Moorean argument for the full moral status of those with profound intellectual disability

This paper is about the moral status of those human beings with profound intellectual disabilities (PIDs). We hold the common sense view that they have equal status to 'normal' human beings, and a higher status than any non-human animal. We start with an admission, however: we don’t know how to give a fully satisfying theoretical account of the grounds of moral status that explains this view. And in fact, not only do we not know how to give such an account, but the most satisfying account of moral status that we know (which we call 'the standard account') entails that our view is false. It entails that those with PIDs have a lower status than ordinary human beings and an equal status to non-human animals. Now, in this paper, we do absolutely nothing to try to show where the standard account goes wrong, and we do absolutely nothing to resolve the difficulties we see in developing an alternative account that supports our view. Indeed, we do not give any argument against the standard account or in favour of our own view. Instead, we raise the following question: in order to be justified in continuing to hold our view, are we obliged to give such an account? Our answer will be that we are not. In section 1 we emphasise just how common our view is, and how deeply held it is, before outlining the difficulties surrounding giving a theoretical account that justifies it. After introducing the Moorean strategy in section 2, in section 3 we argue that despite these difficulties, and despite the fact that we do not know how to overcome them, it is not the case that we ought to abandon our view. The Moorean strategy we employ is drawn from a common interpretation of G. E. Moore's famous proof of the external world (due to William Lycan). Our argument is that the strategy that Lycan's Moore applies in that case can be successfully applied in the case of our view too

Study of radiation hazards to man on extended near earth missions

Radiation hazards to man on extended near earth mission

Definition of ground test for verification of large space structure control

Control theory and design, dynamic system modelling, and simulation of test scenarios are the main ideas discussed. The overall effort is the achievement at Marshall Space Flight Center of a successful ground test experiment of a large space structure. A simplified planar model of ground test experiment of a large space structure. A simplified planar model of ground test verification was developed. The elimination from that model of the uncontrollable rigid body modes was also examined. Also studied was the hardware/software of computation speed

Gauge covariance and the fermion-photon vertex in three- and four- dimensional, massless quantum electrodynamics

In the quenched approximation, the gauge covariance properties of three vertex Ans\"{a}tze in the Schwinger-Dyson equation for the fermion self energy are analysed in three- and four- dimensional quantum electrodynamics. Based on the Cornwall-Jackiw-Tomboulis effective action, it is inferred that the spectral representation used for the vertex in the gauge technique cannot support dynamical chiral symmetry breaking. A criterion for establishing whether a given Ansatz can confer gauge covariance upon the Schwinger-Dyson equation is presented and the Curtis and Pennington Ansatz is shown to satisfy this constraint. We obtain an analytic solution of the Schwinger-Dyson equation for quenched, massless three-dimensional quantum electrodynamics for arbitrary values of the gauge parameter in the absence of dynamical chiral symmetry breaking.Comment: 17 pages, PHY-7143-TH-93, REVTE