Vehicle Design for Mars Landing and Return to Mars Orbit

This paper briefly describes three modes for accomplishing the Mars landing mission and compares them on a gross basis to indicate their probable order of merit and to identify design requirements placed on the Mars-excursion module (MEM) by the choice of mode. The paper shows that a flyby-rendezvous mode requiring low weight in earth orbit requires the MEM to enter the Mars atmosphere at velocities ranging from 20,000 to 30,000 ft/sec. The MEM for the flyby-rendezvous mode is not covered in this paper but merits further study. The MEM for the other modes of mission accomplishment begins its active operational sequence in Mars orbit and need not be greatly influenced by the method of delivery to Mars orbit. Parametric studies of the entry problem for two vehicles typifying a ballistic-type and a lifting-body-type were conducted to identify the problems associated with design of a MEM to accommodate the extremes of Mars atmospheric density presently predicted. This brief study indicates that: (a) the presently predicted density extremes of the Mars atmosphere present no serious design problems for a MEM which can operate across the entire band of predicted densities; (b) details of operational requirements and mission objectives will control the choice of configuration rather than entry requirements; and (c) the ballistic-type MEM is lighter and simpler but has less operational flexibility than a high L/D MEM

The changes in chemical composition during development of the bovine nuchal ligament

Whole bovine nuchal ligaments, or portions thereof (in the case of commercially valuable animals), were obtained from 45 animals (28 fetal and 17 postnatal) ranging in age from 110 days of gestation to 10 yr. Insoluble elastin was quantitatively prepared from the fresh ligaments by extraction with hot alkali and by a combination of multiple extractions with alkaline buffer and then repeated autoclaving. When adult samples were examined, the yields of insoluble residue by these two methods were very similar, but with young fetal samples the second method gave significantly higher values, because of incomplete purification of the elastin residue. The changes in the concentration of collagen, alkali-insoluble elastin, and DNA have been examined. DNA concentration, and, thus, cell population density, fell progressively during the fetal period of development, to reach a steady value soon after birth. Collagen appeared in appreciable quantities before elastin, but its concentration was rapidly halved at about the time of birth. Insoluble elastin concentration was low until the end of the 7th fetal month, at which time it began to rise rapidly. The rate of increase in elastin concentration remained high throughout the next 10–12 wk, by which time the adult value had been reached. Quantitative studies, on the basis of the whole ligament, showed that the total cell content rises to a maximum at birth, but falls soon after to a level about half that at birth. Total collagen production and elastin deposition continue at a steady, maximal rate over the interval from 235 days of gestation to the end of the 1st postnatal month. It is concluded that the immediate postnatal period would be the most favorable phase in which to attempt the isolation of the soluble precursor elastin

Spin-Statistics Violations in Superstring Theory

I describe how superstring theory may violate spin-statistics in an experimentally observable manner. Reviewing the basics of superstring interactions and how to utilize these to produce a statistical phase, I then apply these ideas to two specific examples. The first is the case of heterotic worldsheet linkings, whereby one small closed string momentarily enlarges sufficiently to pass over another, producing such a statistical phase. The second is the braneworld model with noncommutative geometry, whereby matter composed of open strings may couple to a background in which spacetime coordinates do not commute, modifying the field (anti)commutator algebra. I conclude with ways to sharpen and experimentally test these exciting avenues to possibly verify superstring theory.Comment: 18 pages, 3 figures; v2: references added and typos correcte

Elastic energy loss and longitudinal straggling of a hard jet

The elastic energy loss encountered by jets produced in deep-inelastic scattering (DIS) off a large nucleus is studied in the collinear limit. In close analogy to the case of (non-radiative) transverse momentum broadening, which is dependent on the medium transport coefficient $\hat{q}$, a class of medium enhanced higher twist operators which contribute to the non-radiative loss of the forward light-cone momentum of the jet ($q^-$) are identified and the leading correction in the limit of asymptotically high $q^-$ is isolated. Based on these operator products, a new transport coefficient $\hat{e}$ is motivated which quantifies the energy loss per unit length encountered by the hard jet. These operator products are then computed, explicitly, in the case of a similar hard jet traversing a deconfined quark-gluon-plasma (QGP) in the hard-thermal-loop (HTL) approximation. This is followed by an evaluation of sub-leading contributions which are suppressed by the light-cone momentum $q^-$, which yields the longitudinal "straggling" i.e., a slight change in light cone momentum due to the Brownian propagation through a medium with a fluctuating color field.Comment: 5 pages, 1 figure, Revtex

Investigation of light scattering in highly reflecting pigmented coatings. Volume 3 - Monte Carlo and other statistical investigations Final report, 1 May 1963 - 30 Sep. 1966

Monte Carlo methods, Mie theory, and random walk and screen models for predicting reflective properties of paint film

The incidence and position of melanocytic nevi for the purposes of forensic image comparison

Expert witness opinion based on the comparison of images has been accepted by UK courts as admissible evidence in relation to issues of identity. Within images of the hand are a multiplicity of anatomical features of different aetiology, incidence and distribution patterns and this includes melanocytic nevi, referred to more colloquially as moles and/or birthmarks. The hand is not a common place for these isolated features to develop and so their presence in this anatomical region has the potential to be useful for issues of identity. The results of this study show that approximately 9 % of individuals in a sample of 476 hands, displayed at least one nevus on the back of their hand and, contrary to the literature, the incidence was found to be greater in females (15 % of female cohort) than males (7 % of male cohort). Almost a third of all nevi identified on the dorsum of the hand were abnormal or dysplastic. The most frequent location for these aggregations of melanocytes was in the central region of the dorsum of the hand or at the base of the index finger. The relevance of nevi identified in the image of a perpetrator’s hand and also on that of a suspect/accused is discussed in relation to the issue of whether the images have originated from the same individual

Investigation of Light Scattering in Highly Reflecting Pigmented Coatings Quarterly Report, Feb. 1 - May 1, 1966

Monte Carlo method applied to pigment particle clusters, and relevance of Mie scattering function to reflected ligh

Investigation of light scattering in highly reflecting pigmented coatings Quarterly report, Nov. 1, 1965 - Feb. 1, 1966

Monte Carlo treatment to find light scattering parameters of metal filled, reflecting pigmented coating